Mechanical change to use <sys/queue.h> macro API instead of

[FreeBSD/FreeBSD.git] / sys / cam / cam_xpt.c

/*
 * Implementation of the Common Access Method Transport (XPT) layer.
 *
 * Copyright (c) 1997, 1998, 1999 Justin T. Gibbs.
 * Copyright (c) 1997, 1998, 1999 Kenneth D. Merry.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions, and the following disclaimer,
 *    without modification, immediately at the beginning of the file.
 * 2. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * $FreeBSD$
 */
#include <sys/param.h>
#include <sys/bus.h>
#include <sys/systm.h>
#include <sys/types.h>
#include <sys/malloc.h>
#include <sys/kernel.h>
#include <sys/time.h>
#include <sys/conf.h>
#include <sys/fcntl.h>
#include <sys/md5.h>
#include <sys/devicestat.h>
#include <sys/interrupt.h>

#ifdef PC98
#include <pc98/pc98/pc98_machdep.h>     /* geometry translation */
#endif

#include <sys/ipl.h>

#include <cam/cam.h>
#include <cam/cam_ccb.h>
#include <cam/cam_periph.h>
#include <cam/cam_sim.h>
#include <cam/cam_xpt.h>
#include <cam/cam_xpt_sim.h>
#include <cam/cam_xpt_periph.h>
#include <cam/cam_debug.h>

#include <cam/scsi/scsi_all.h>
#include <cam/scsi/scsi_message.h>
#include <cam/scsi/scsi_pass.h>
#include "opt_cam.h"

/* Datastructures internal to the xpt layer */

/*
 * Definition of an async handler callback block.  These are used to add
 * SIMs and peripherals to the async callback lists.
 */
struct async_node {
        SLIST_ENTRY(async_node) links;
        u_int32_t       event_enable;   /* Async Event enables */
        void            (*callback)(void *arg, u_int32_t code,
                                    struct cam_path *path, void *args);
        void            *callback_arg;
};

SLIST_HEAD(async_list, async_node);
SLIST_HEAD(periph_list, cam_periph);
static STAILQ_HEAD(highpowerlist, ccb_hdr) highpowerq;

/*
 * This is the maximum number of high powered commands (e.g. start unit)
 * that can be outstanding at a particular time.
 */
#ifndef CAM_MAX_HIGHPOWER
#define CAM_MAX_HIGHPOWER  4
#endif

/* number of high powered commands that can go through right now */
static int num_highpower = CAM_MAX_HIGHPOWER;

/*
 * Structure for queueing a device in a run queue.
 * There is one run queue for allocating new ccbs,
 * and another for sending ccbs to the controller.
 */
struct cam_ed_qinfo {
        cam_pinfo pinfo;
        struct    cam_ed *device;
};

/*
 * The CAM EDT (Existing Device Table) contains the device information for
 * all devices for all busses in the system.  The table contains a
 * cam_ed structure for each device on the bus.
 */
struct cam_ed {
        TAILQ_ENTRY(cam_ed) links;
        struct  cam_ed_qinfo alloc_ccb_entry;
        struct  cam_ed_qinfo send_ccb_entry;
        struct  cam_et   *target;
        lun_id_t         lun_id;
        struct  camq drvq;              /*
                                         * Queue of type drivers wanting to do
                                         * work on this device.
                                         */
        struct  cam_ccbq ccbq;          /* Queue of pending ccbs */
        struct  async_list asyncs;      /* Async callback info for this B/T/L */
        struct  periph_list periphs;    /* All attached devices */
        u_int   generation;             /* Generation number */
        struct  cam_periph *owner;      /* Peripheral driver's ownership tag */
        struct  xpt_quirk_entry *quirk; /* Oddities about this device */
                                        /* Storage for the inquiry data */
        struct  scsi_inquiry_data inq_data;
        u_int8_t         inq_flags;     /*
                                         * Current settings for inquiry flags.
                                         * This allows us to override settings
                                         * like disconnection and tagged
                                         * queuing for a device.
                                         */
        u_int8_t         queue_flags;   /* Queue flags from the control page */
        u_int8_t         serial_num_len;
        u_int8_t         *serial_num;
        u_int32_t        qfrozen_cnt;
        u_int32_t        flags;
#define CAM_DEV_UNCONFIGURED            0x01
#define CAM_DEV_REL_TIMEOUT_PENDING     0x02
#define CAM_DEV_REL_ON_COMPLETE         0x04
#define CAM_DEV_REL_ON_QUEUE_EMPTY      0x08
#define CAM_DEV_RESIZE_QUEUE_NEEDED     0x10
#define CAM_DEV_TAG_AFTER_COUNT         0x20
#define CAM_DEV_INQUIRY_DATA_VALID      0x40
        u_int32_t        tag_delay_count;
#define CAM_TAG_DELAY_COUNT             5
        u_int32_t        refcount;
        struct           callout_handle c_handle;
};

/*
 * Each target is represented by an ET (Existing Target).  These
 * entries are created when a target is successfully probed with an
 * identify, and removed when a device fails to respond after a number
 * of retries, or a bus rescan finds the device missing.
 */
struct cam_et { 
        TAILQ_HEAD(, cam_ed) ed_entries;
        TAILQ_ENTRY(cam_et) links;
        struct  cam_eb  *bus;   
        target_id_t     target_id;
        u_int32_t       refcount;       
        u_int           generation;
        struct          timeval last_reset;
};

/*
 * Each bus is represented by an EB (Existing Bus).  These entries
 * are created by calls to xpt_bus_register and deleted by calls to
 * xpt_bus_deregister.
 */
struct cam_eb { 
        TAILQ_HEAD(, cam_et) et_entries;
        TAILQ_ENTRY(cam_eb)  links;
        path_id_t            path_id;
        struct cam_sim       *sim;
        struct timeval       last_reset;
        u_int32_t            flags;
#define CAM_EB_RUNQ_SCHEDULED   0x01
        u_int32_t            refcount;
        u_int                generation;
};

struct cam_path {
        struct cam_periph *periph;
        struct cam_eb     *bus;
        struct cam_et     *target;
        struct cam_ed     *device;
};

struct xpt_quirk_entry {
        struct scsi_inquiry_pattern inq_pat;
        u_int8_t quirks;
#define CAM_QUIRK_NOLUNS        0x01
#define CAM_QUIRK_NOSERIAL      0x02
#define CAM_QUIRK_HILUNS        0x04
        u_int mintags;
        u_int maxtags;
};
#define CAM_SCSI2_MAXLUN        8

typedef enum {
        XPT_FLAG_OPEN           = 0x01
} xpt_flags;

struct xpt_softc {
        xpt_flags       flags;
        u_int32_t       generation;
};

static const char quantum[] = "QUANTUM";
static const char sony[] = "SONY";
static const char west_digital[] = "WDIGTL";
static const char samsung[] = "SAMSUNG";
static const char seagate[] = "SEAGATE";
static const char microp[] = "MICROP";

static struct xpt_quirk_entry xpt_quirk_table[] = 
{
        {
                /* Reports QUEUE FULL for temporary resource shortages */
                { T_DIRECT, SIP_MEDIA_FIXED, quantum, "XP39100*", "*" },
                /*quirks*/0, /*mintags*/24, /*maxtags*/32
        },
        {
                /* Reports QUEUE FULL for temporary resource shortages */
                { T_DIRECT, SIP_MEDIA_FIXED, quantum, "XP34550*", "*" },
                /*quirks*/0, /*mintags*/24, /*maxtags*/32
        },
        {
                /* Reports QUEUE FULL for temporary resource shortages */
                { T_DIRECT, SIP_MEDIA_FIXED, quantum, "XP32275*", "*" },
                /*quirks*/0, /*mintags*/24, /*maxtags*/32
        },
        {
                /* Broken tagged queuing drive */
                { T_DIRECT, SIP_MEDIA_FIXED, microp, "4421-07*", "*" },
                /*quirks*/0, /*mintags*/0, /*maxtags*/0
        },
        {
                /* Broken tagged queuing drive */
                { T_DIRECT, SIP_MEDIA_FIXED, "HP", "C372*", "*" },
                /*quirks*/0, /*mintags*/0, /*maxtags*/0
        },
        {
                /* Broken tagged queuing drive */
                { T_DIRECT, SIP_MEDIA_FIXED, microp, "3391*", "x43h" },
                /*quirks*/0, /*mintags*/0, /*maxtags*/0
        },
        {
                /*
                 * Unfortunately, the Quantum Atlas III has the same
                 * problem as the Atlas II drives above.
                 * Reported by: "Johan Granlund" <johan@granlund.nu>
                 *
                 * For future reference, the drive with the problem was:
                 * QUANTUM QM39100TD-SW N1B0
                 * 
                 * It's possible that Quantum will fix the problem in later
                 * firmware revisions.  If that happens, the quirk entry
                 * will need to be made specific to the firmware revisions
                 * with the problem.
                 * 
                 */
                /* Reports QUEUE FULL for temporary resource shortages */
                { T_DIRECT, SIP_MEDIA_FIXED, quantum, "QM39100*", "*" },
                /*quirks*/0, /*mintags*/24, /*maxtags*/32
        },
        {
                /*
                 * 18 Gig Atlas III, same problem as the 9G version.
                 * Reported by: Andre Albsmeier
                 *              <andre.albsmeier@mchp.siemens.de>
                 *
                 * For future reference, the drive with the problem was:
                 * QUANTUM QM318000TD-S N491
                 */
                /* Reports QUEUE FULL for temporary resource shortages */
                { T_DIRECT, SIP_MEDIA_FIXED, quantum, "QM318000*", "*" },
                /*quirks*/0, /*mintags*/24, /*maxtags*/32
        },
        {
                /*
                 * Broken tagged queuing drive
                 * Reported by: Bret Ford <bford@uop.cs.uop.edu>
                 *         and: Martin Renters <martin@tdc.on.ca>
                 */
                { T_DIRECT, SIP_MEDIA_FIXED, seagate, "ST410800*", "71*" },
                /*quirks*/0, /*mintags*/0, /*maxtags*/0
        },
                /*
                 * The Seagate Medalist Pro drives have very poor write
                 * performance with anything more than 2 tags.
                 * 
                 * Reported by:  Paul van der Zwan <paulz@trantor.xs4all.nl>
                 * Drive:  <SEAGATE ST36530N 1444>
                 *
                 * Reported by:  Jeremy Lea <reg@shale.csir.co.za>
                 * Drive:  <SEAGATE ST34520W 1281>
                 *
                 * No one has actually reported that the 9G version
                 * (ST39140*) of the Medalist Pro has the same problem, but
                 * we're assuming that it does because the 4G and 6.5G
                 * versions of the drive are broken.
                 */
        {
                { T_DIRECT, SIP_MEDIA_FIXED, seagate, "ST34520*", "*"},
                /*quirks*/0, /*mintags*/2, /*maxtags*/2
        },
        {
                { T_DIRECT, SIP_MEDIA_FIXED, seagate, "ST36530*", "*"},
                /*quirks*/0, /*mintags*/2, /*maxtags*/2
        },
        {
                { T_DIRECT, SIP_MEDIA_FIXED, seagate, "ST39140*", "*"},
                /*quirks*/0, /*mintags*/2, /*maxtags*/2
        },
        {
                /*
                 * Slow when tagged queueing is enabled.  Write performance
                 * steadily drops off with more and more concurrent
                 * transactions.  Best sequential write performance with
                 * tagged queueing turned off and write caching turned on.
                 *
                 * PR:  kern/10398
                 * Submitted by:  Hideaki Okada <hokada@isl.melco.co.jp>
                 * Drive:  DCAS-34330 w/ "S65A" firmware.
                 *
                 * The drive with the problem had the "S65A" firmware
                 * revision, and has also been reported (by Stephen J.
                 * Roznowski <sjr@home.net>) for a drive with the "S61A"
                 * firmware revision.
                 *
                 * Although no one has reported problems with the 2 gig
                 * version of the DCAS drive, the assumption is that it
                 * has the same problems as the 4 gig version.  Therefore
                 * this quirk entries disables tagged queueing for all
                 * DCAS drives.
                 */
                { T_DIRECT, SIP_MEDIA_FIXED, "IBM", "DCAS*", "*" },
                /*quirks*/0, /*mintags*/0, /*maxtags*/0
        },
        {
                /* Broken tagged queuing drive */
                { T_DIRECT, SIP_MEDIA_REMOVABLE, "iomega", "jaz*", "*" },
                /*quirks*/0, /*mintags*/0, /*maxtags*/0
        },
        {
                /* Broken tagged queuing drive */ 
                { T_DIRECT, SIP_MEDIA_FIXED, "CONNER", "CFP2107*", "*" },
                /*quirks*/0, /*mintags*/0, /*maxtags*/0
        },
        {
                /*
                 * Broken tagged queuing drive.
                 * Submitted by:
                 * NAKAJI Hiroyuki <nakaji@zeisei.dpri.kyoto-u.ac.jp>
                 * in PR kern/9535
                 */
                { T_DIRECT, SIP_MEDIA_FIXED, samsung, "WN34324U*", "*" },
                /*quirks*/0, /*mintags*/0, /*maxtags*/0
        },
        {
                /*
                 * Slow when tagged queueing is enabled. (1.5MB/sec versus
                 * 8MB/sec.)
                 * Submitted by: Andrew Gallatin <gallatin@cs.duke.edu>
                 * Best performance with these drives is achieved with
                 * tagged queueing turned off, and write caching turned on.
                 */
                { T_DIRECT, SIP_MEDIA_FIXED, west_digital, "WDE*", "*" },
                /*quirks*/0, /*mintags*/0, /*maxtags*/0
        },
        {
                /*
                 * Slow when tagged queueing is enabled. (1.5MB/sec versus
                 * 8MB/sec.)
                 * Submitted by: Andrew Gallatin <gallatin@cs.duke.edu>
                 * Best performance with these drives is achieved with
                 * tagged queueing turned off, and write caching turned on.
                 */
                { T_DIRECT, SIP_MEDIA_FIXED, west_digital, "ENTERPRISE", "*" },
                /*quirks*/0, /*mintags*/0, /*maxtags*/0
        },
        {
                /*
                 * Doesn't handle queue full condition correctly,
                 * so we need to limit maxtags to what the device
                 * can handle instead of determining this automatically.
                 */
                { T_DIRECT, SIP_MEDIA_FIXED, samsung, "WN321010S*", "*" },
                /*quirks*/0, /*mintags*/2, /*maxtags*/32
        },
        {
                /* Really only one LUN */
                { T_ENCLOSURE, SIP_MEDIA_FIXED, "SUN", "SENA*", "*" },
                CAM_QUIRK_NOLUNS, /*mintags*/0, /*maxtags*/0
        },
        {
                /* I can't believe we need a quirk for DPT volumes. */
                { T_ANY, SIP_MEDIA_FIXED|SIP_MEDIA_REMOVABLE, "DPT", "*", "*" },
                CAM_QUIRK_NOSERIAL|CAM_QUIRK_NOLUNS,
                /*mintags*/0, /*maxtags*/255
        },
        {
                /*
                 * Many Sony CDROM drives don't like multi-LUN probing.
                 */
                { T_CDROM, SIP_MEDIA_REMOVABLE, sony, "CD-ROM CDU*", "*" },
                CAM_QUIRK_NOLUNS, /*mintags*/0, /*maxtags*/0
        },
        {
                /*
                 * This drive doesn't like multiple LUN probing.
                 * Submitted by:  Parag Patel <parag@cgt.com>
                 */
                { T_WORM, SIP_MEDIA_REMOVABLE, sony, "CD-R   CDU9*", "*" },
                CAM_QUIRK_NOLUNS, /*mintags*/0, /*maxtags*/0
        },
        {
                { T_WORM, SIP_MEDIA_REMOVABLE, "YAMAHA", "CDR100*", "*" },
                CAM_QUIRK_NOLUNS, /*mintags*/0, /*maxtags*/0
        },
        {
                /*
                 * The 8200 doesn't like multi-lun probing, and probably
                 * don't like serial number requests either.
                 */
                {
                        T_SEQUENTIAL, SIP_MEDIA_REMOVABLE, "EXABYTE",
                        "EXB-8200*", "*"
                },
                CAM_QUIRK_NOSERIAL|CAM_QUIRK_NOLUNS, /*mintags*/0, /*maxtags*/0
        },
        {
                /*
                 * These Hitachi drives don't like multi-lun probing.
                 * The PR submitter has a DK319H, but says that the Linux
                 * kernel has a similar work-around for the DK312 and DK314,
                 * so all DK31* drives are quirked here.
                 * PR:            misc/18793
                 * Submitted by:  Paul Haddad <paul@pth.com>
                 */
                { T_DIRECT, SIP_MEDIA_FIXED, "HITACHI", "DK31*", "*" },
                CAM_QUIRK_NOLUNS, /*mintags*/2, /*maxtags*/255
        },
        {
                /*
                 * This old revision of the TDC3600 is also SCSI-1, and
                 * hangs upon serial number probing.
                 */
                {
                        T_SEQUENTIAL, SIP_MEDIA_REMOVABLE, "TANDBERG",
                        " TDC 3600", "U07:"
                },
                CAM_QUIRK_NOSERIAL, /*mintags*/0, /*maxtags*/0
        },
        {
                /*
                 * Would repond to all LUNs if asked for.
                 */
                {
                        T_SEQUENTIAL, SIP_MEDIA_REMOVABLE, "CALIPER",
                        "CP150", "*"
                },
                CAM_QUIRK_NOLUNS, /*mintags*/0, /*maxtags*/0
        },
        {
                /*
                 * Would repond to all LUNs if asked for.
                 */
                {
                        T_SEQUENTIAL, SIP_MEDIA_REMOVABLE, "KENNEDY",
                        "96X2*", "*"
                },
                CAM_QUIRK_NOLUNS, /*mintags*/0, /*maxtags*/0
        },
        {
                /* Submitted by: Matthew Dodd <winter@jurai.net> */
                { T_PROCESSOR, SIP_MEDIA_FIXED, "Cabletrn", "EA41*", "*" },
                CAM_QUIRK_NOLUNS, /*mintags*/0, /*maxtags*/0
        },
        {
                /* Submitted by: Matthew Dodd <winter@jurai.net> */
                { T_PROCESSOR, SIP_MEDIA_FIXED, "CABLETRN", "EA41*", "*" },
                CAM_QUIRK_NOLUNS, /*mintags*/0, /*maxtags*/0
        },
        {
                /* TeraSolutions special settings for TRC-22 RAID */
                { T_DIRECT, SIP_MEDIA_FIXED, "TERASOLU", "TRC-22", "*" },
                  /*quirks*/0, /*mintags*/55, /*maxtags*/255
        },
        {
                /*
                 * Would respond to all LUNs.  Device type and removable
                 * flag are jumper-selectable.
                 */
                { T_ANY, SIP_MEDIA_REMOVABLE|SIP_MEDIA_FIXED, "MaxOptix",
                  "Tahiti 1", "*"
                },
                CAM_QUIRK_NOLUNS, /*mintags*/0, /*maxtags*/0
        },
        {
                /* Default tagged queuing parameters for all devices */
                {
                  T_ANY, SIP_MEDIA_REMOVABLE|SIP_MEDIA_FIXED,
                  /*vendor*/"*", /*product*/"*", /*revision*/"*"
                },
                /*quirks*/0, /*mintags*/2, /*maxtags*/255
        },
};

static const int xpt_quirk_table_size =
        sizeof(xpt_quirk_table) / sizeof(*xpt_quirk_table);

typedef enum {
        DM_RET_COPY             = 0x01,
        DM_RET_FLAG_MASK        = 0x0f,
        DM_RET_NONE             = 0x00,
        DM_RET_STOP             = 0x10,
        DM_RET_DESCEND          = 0x20,
        DM_RET_ERROR            = 0x30,
        DM_RET_ACTION_MASK      = 0xf0
} dev_match_ret;

typedef enum {
        XPT_DEPTH_BUS,
        XPT_DEPTH_TARGET,
        XPT_DEPTH_DEVICE,
        XPT_DEPTH_PERIPH
} xpt_traverse_depth;

struct xpt_traverse_config {
        xpt_traverse_depth      depth;
        void                    *tr_func;
        void                    *tr_arg;
};

typedef int     xpt_busfunc_t (struct cam_eb *bus, void *arg);
typedef int     xpt_targetfunc_t (struct cam_et *target, void *arg);
typedef int     xpt_devicefunc_t (struct cam_ed *device, void *arg);
typedef int     xpt_periphfunc_t (struct cam_periph *periph, void *arg);
typedef int     xpt_pdrvfunc_t (struct periph_driver **pdrv, void *arg);

/* Transport layer configuration information */
static struct xpt_softc xsoftc;

/* Queues for our software interrupt handler */
typedef TAILQ_HEAD(cam_isrq, ccb_hdr) cam_isrq_t;
static cam_isrq_t cam_bioq;
static cam_isrq_t cam_netq;

/* "Pool" of inactive ccbs managed by xpt_alloc_ccb and xpt_free_ccb */
static SLIST_HEAD(,ccb_hdr) ccb_freeq;
static u_int xpt_max_ccbs;      /*
                                 * Maximum size of ccb pool.  Modified as
                                 * devices are added/removed or have their
                                 * opening counts changed.
                                 */
static u_int xpt_ccb_count;     /* Current count of allocated ccbs */

struct cam_periph *xpt_periph;

static periph_init_t xpt_periph_init;

static periph_init_t probe_periph_init;

static struct periph_driver xpt_driver =
{
        xpt_periph_init, "xpt",
        TAILQ_HEAD_INITIALIZER(xpt_driver.units)
};

static struct periph_driver probe_driver =
{
        probe_periph_init, "probe",
        TAILQ_HEAD_INITIALIZER(probe_driver.units)
};

DATA_SET(periphdriver_set, xpt_driver);
DATA_SET(periphdriver_set, probe_driver);

#define XPT_CDEV_MAJOR 104

static d_open_t xptopen;
static d_close_t xptclose;
static d_ioctl_t xptioctl;

static struct cdevsw xpt_cdevsw = {
        /* open */      xptopen,
        /* close */     xptclose,
        /* read */      noread,
        /* write */     nowrite,
        /* ioctl */     xptioctl,
        /* poll */      nopoll,
        /* mmap */      nommap,
        /* strategy */  nostrategy,
        /* name */      "xpt",
        /* maj */       XPT_CDEV_MAJOR,
        /* dump */      nodump,
        /* psize */     nopsize,
        /* flags */     0,
        /* bmaj */      -1
};

static struct intr_config_hook *xpt_config_hook;

/* Registered busses */
static TAILQ_HEAD(,cam_eb) xpt_busses;
static u_int bus_generation;

/* Storage for debugging datastructures */
#ifdef  CAMDEBUG
struct cam_path *cam_dpath;
u_int32_t cam_dflags;
u_int32_t cam_debug_delay;
#endif

/* Pointers to software interrupt handlers */
struct intrhand *camnet_ih;
struct intrhand *cambio_ih;

#if defined(CAM_DEBUG_FLAGS) && !defined(CAMDEBUG)
#error "You must have options CAMDEBUG to use options CAM_DEBUG_FLAGS"
#endif

/*
 * In order to enable the CAM_DEBUG_* options, the user must have CAMDEBUG
 * enabled.  Also, the user must have either none, or all of CAM_DEBUG_BUS,
 * CAM_DEBUG_TARGET, and CAM_DEBUG_LUN specified.
 */
#if defined(CAM_DEBUG_BUS) || defined(CAM_DEBUG_TARGET) \
    || defined(CAM_DEBUG_LUN)
#ifdef CAMDEBUG
#if !defined(CAM_DEBUG_BUS) || !defined(CAM_DEBUG_TARGET) \
    || !defined(CAM_DEBUG_LUN)
#error "You must define all or none of CAM_DEBUG_BUS, CAM_DEBUG_TARGET \
        and CAM_DEBUG_LUN"
#endif /* !CAM_DEBUG_BUS || !CAM_DEBUG_TARGET || !CAM_DEBUG_LUN */
#else /* !CAMDEBUG */
#error "You must use options CAMDEBUG if you use the CAM_DEBUG_* options"
#endif /* CAMDEBUG */
#endif /* CAM_DEBUG_BUS || CAM_DEBUG_TARGET || CAM_DEBUG_LUN */

/* Our boot-time initialization hook */
static int cam_module_event_handler(module_t, int /*modeventtype_t*/, void *);

static moduledata_t cam_moduledata = {
        "cam",
        cam_module_event_handler,
        NULL
};

static void     xpt_init(void *);

DECLARE_MODULE(cam, cam_moduledata, SI_SUB_CONFIGURE, SI_ORDER_SECOND);
MODULE_VERSION(cam, 1);


static cam_status       xpt_compile_path(struct cam_path *new_path,
                                         struct cam_periph *perph,
                                         path_id_t path_id,
                                         target_id_t target_id,
                                         lun_id_t lun_id);

static void             xpt_release_path(struct cam_path *path);

static void             xpt_async_bcast(struct async_list *async_head,
                                        u_int32_t async_code,
                                        struct cam_path *path,
                                        void *async_arg);
static void             xpt_dev_async(u_int32_t async_code,
                                      struct cam_eb *bus,
                                      struct cam_et *target,
                                      struct cam_ed *device,
                                      void *async_arg);
static path_id_t xptnextfreepathid(void);
static path_id_t xptpathid(const char *sim_name, int sim_unit, int sim_bus);
static union ccb *xpt_get_ccb(struct cam_ed *device);
static int       xpt_schedule_dev(struct camq *queue, cam_pinfo *dev_pinfo,
                                  u_int32_t new_priority);
static void      xpt_run_dev_allocq(struct cam_eb *bus);
static void      xpt_run_dev_sendq(struct cam_eb *bus);
static timeout_t xpt_release_devq_timeout;
static timeout_t xpt_release_simq_timeout;
static void      xpt_release_bus(struct cam_eb *bus);
static void      xpt_release_devq_device(struct cam_ed *dev, u_int count,
                                         int run_queue);
static struct cam_et*
                 xpt_alloc_target(struct cam_eb *bus, target_id_t target_id);
static void      xpt_release_target(struct cam_eb *bus, struct cam_et *target);
static struct cam_ed*
                 xpt_alloc_device(struct cam_eb *bus, struct cam_et *target,
                                  lun_id_t lun_id);
static void      xpt_release_device(struct cam_eb *bus, struct cam_et *target,
                                    struct cam_ed *device);
static u_int32_t xpt_dev_ccbq_resize(struct cam_path *path, int newopenings);
static struct cam_eb*
                 xpt_find_bus(path_id_t path_id);
static struct cam_et*
                 xpt_find_target(struct cam_eb *bus, target_id_t target_id);
static struct cam_ed*
                 xpt_find_device(struct cam_et *target, lun_id_t lun_id);
static void      xpt_scan_bus(struct cam_periph *periph, union ccb *ccb);
static void      xpt_scan_lun(struct cam_periph *periph,
                              struct cam_path *path, cam_flags flags,
                              union ccb *ccb);
static void      xptscandone(struct cam_periph *periph, union ccb *done_ccb);
static xpt_busfunc_t    xptconfigbuscountfunc;
static xpt_busfunc_t    xptconfigfunc;
static void      xpt_config(void *arg);
static xpt_devicefunc_t xptpassannouncefunc;
static void      xpt_finishconfig(struct cam_periph *periph, union ccb *ccb);
static void      xptaction(struct cam_sim *sim, union ccb *work_ccb);
static void      xptpoll(struct cam_sim *sim);
static void      camisr(void *);
#if 0
static void      xptstart(struct cam_periph *periph, union ccb *work_ccb);
static void      xptasync(struct cam_periph *periph,
                          u_int32_t code, cam_path *path);
#endif
static dev_match_ret    xptbusmatch(struct dev_match_pattern *patterns,
                                    int num_patterns, struct cam_eb *bus);
static dev_match_ret    xptdevicematch(struct dev_match_pattern *patterns,
                                       int num_patterns, struct cam_ed *device);
static dev_match_ret    xptperiphmatch(struct dev_match_pattern *patterns,
                                       int num_patterns,
                                       struct cam_periph *periph);
static xpt_busfunc_t    xptedtbusfunc;
static xpt_targetfunc_t xptedttargetfunc;
static xpt_devicefunc_t xptedtdevicefunc;
static xpt_periphfunc_t xptedtperiphfunc;
static xpt_pdrvfunc_t   xptplistpdrvfunc;
static xpt_periphfunc_t xptplistperiphfunc;
static int              xptedtmatch(struct ccb_dev_match *cdm);
static int              xptperiphlistmatch(struct ccb_dev_match *cdm);
static int              xptbustraverse(struct cam_eb *start_bus,
                                       xpt_busfunc_t *tr_func, void *arg);
static int              xpttargettraverse(struct cam_eb *bus,
                                          struct cam_et *start_target,
                                          xpt_targetfunc_t *tr_func, void *arg);
static int              xptdevicetraverse(struct cam_et *target,
                                          struct cam_ed *start_device,
                                          xpt_devicefunc_t *tr_func, void *arg);
static int              xptperiphtraverse(struct cam_ed *device,
                                          struct cam_periph *start_periph,
                                          xpt_periphfunc_t *tr_func, void *arg);
static int              xptpdrvtraverse(struct periph_driver **start_pdrv,
                                        xpt_pdrvfunc_t *tr_func, void *arg);
static int              xptpdperiphtraverse(struct periph_driver **pdrv,
                                            struct cam_periph *start_periph,
                                            xpt_periphfunc_t *tr_func,
                                            void *arg);
static xpt_busfunc_t    xptdefbusfunc;
static xpt_targetfunc_t xptdeftargetfunc;
static xpt_devicefunc_t xptdefdevicefunc;
static xpt_periphfunc_t xptdefperiphfunc;
static int              xpt_for_all_busses(xpt_busfunc_t *tr_func, void *arg);
#ifdef notusedyet
static int              xpt_for_all_targets(xpt_targetfunc_t *tr_func,
                                            void *arg);
#endif
static int              xpt_for_all_devices(xpt_devicefunc_t *tr_func,
                                            void *arg);
#ifdef notusedyet
static int              xpt_for_all_periphs(xpt_periphfunc_t *tr_func,
                                            void *arg);
#endif
static xpt_devicefunc_t xptsetasyncfunc;
static xpt_busfunc_t    xptsetasyncbusfunc;
static cam_status       xptregister(struct cam_periph *periph,
                                    void *arg);
static cam_status       proberegister(struct cam_periph *periph,
                                      void *arg);
static void      probeschedule(struct cam_periph *probe_periph);
static void      probestart(struct cam_periph *periph, union ccb *start_ccb);
static void      proberequestdefaultnegotiation(struct cam_periph *periph);
static void      probedone(struct cam_periph *periph, union ccb *done_ccb);
static void      probecleanup(struct cam_periph *periph);
static void      xpt_find_quirk(struct cam_ed *device);
static void      xpt_set_transfer_settings(struct ccb_trans_settings *cts,
                                           struct cam_ed *device,
                                           int async_update);
static void      xpt_toggle_tags(struct cam_path *path);
static void      xpt_start_tags(struct cam_path *path);
static __inline int xpt_schedule_dev_allocq(struct cam_eb *bus,
                                            struct cam_ed *dev);
static __inline int xpt_schedule_dev_sendq(struct cam_eb *bus,
                                           struct cam_ed *dev);
static __inline int periph_is_queued(struct cam_periph *periph);
static __inline int device_is_alloc_queued(struct cam_ed *device);
static __inline int device_is_send_queued(struct cam_ed *device);
static __inline int dev_allocq_is_runnable(struct cam_devq *devq);

static __inline int
xpt_schedule_dev_allocq(struct cam_eb *bus, struct cam_ed *dev)
{
        int retval;

        if (dev->ccbq.devq_openings > 0) {
                if ((dev->flags & CAM_DEV_RESIZE_QUEUE_NEEDED) != 0) {
                        cam_ccbq_resize(&dev->ccbq,
                                        dev->ccbq.dev_openings
                                        + dev->ccbq.dev_active);
                        dev->flags &= ~CAM_DEV_RESIZE_QUEUE_NEEDED;
                }
                /*
                 * The priority of a device waiting for CCB resources
                 * is that of the the highest priority peripheral driver
                 * enqueued.
                 */
                retval = xpt_schedule_dev(&bus->sim->devq->alloc_queue,
                                          &dev->alloc_ccb_entry.pinfo,
                                          CAMQ_GET_HEAD(&dev->drvq)->priority); 
        } else {
                retval = 0;
        }

        return (retval);
}

static __inline int
xpt_schedule_dev_sendq(struct cam_eb *bus, struct cam_ed *dev)
{
        int     retval;

        if (dev->ccbq.dev_openings > 0) {
                /*
                 * The priority of a device waiting for controller
                 * resources is that of the the highest priority CCB
                 * enqueued.
                 */
                retval =
                    xpt_schedule_dev(&bus->sim->devq->send_queue,
                                     &dev->send_ccb_entry.pinfo,
                                     CAMQ_GET_HEAD(&dev->ccbq.queue)->priority);
        } else {
                retval = 0;
        }
        return (retval);
}

static __inline int
periph_is_queued(struct cam_periph *periph)
{
        return (periph->pinfo.index != CAM_UNQUEUED_INDEX);
}

static __inline int
device_is_alloc_queued(struct cam_ed *device)
{
        return (device->alloc_ccb_entry.pinfo.index != CAM_UNQUEUED_INDEX);
}

static __inline int
device_is_send_queued(struct cam_ed *device)
{
        return (device->send_ccb_entry.pinfo.index != CAM_UNQUEUED_INDEX);
}

static __inline int
dev_allocq_is_runnable(struct cam_devq *devq)
{
        /*
         * Have work to do.
         * Have space to do more work.
         * Allowed to do work.
         */
        return ((devq->alloc_queue.qfrozen_cnt == 0)
             && (devq->alloc_queue.entries > 0)
             && (devq->alloc_openings > 0));
}

static void
xpt_periph_init()
{
        make_dev(&xpt_cdevsw, 0, UID_ROOT, GID_OPERATOR, 0600, "xpt0");
}

static void
probe_periph_init()
{
}


static void
xptdone(struct cam_periph *periph, union ccb *done_ccb)
{
        /* Caller will release the CCB */
        wakeup(&done_ccb->ccb_h.cbfcnp);
}

static int
xptopen(dev_t dev, int flags, int fmt, struct proc *p)
{
        int unit;

        unit = minor(dev) & 0xff;

        /*
         * Only allow read-write access.
         */
        if (((flags & FWRITE) == 0) || ((flags & FREAD) == 0))
                return(EPERM);

        /*
         * We don't allow nonblocking access.
         */
        if ((flags & O_NONBLOCK) != 0) {
                printf("xpt%d: can't do nonblocking accesss\n", unit);
                return(ENODEV);
        }

        /*
         * We only have one transport layer right now.  If someone accesses
         * us via something other than minor number 1, point out their
         * mistake.
         */
        if (unit != 0) {
                printf("xptopen: got invalid xpt unit %d\n", unit);
                return(ENXIO);
        }

        /* Mark ourselves open */
        xsoftc.flags |= XPT_FLAG_OPEN;
        
        return(0);
}

static int
xptclose(dev_t dev, int flag, int fmt, struct proc *p)
{
        int unit;

        unit = minor(dev) & 0xff;

        /*
         * We only have one transport layer right now.  If someone accesses
         * us via something other than minor number 1, point out their
         * mistake.
         */
        if (unit != 0) {
                printf("xptclose: got invalid xpt unit %d\n", unit);
                return(ENXIO);
        }

        /* Mark ourselves closed */
        xsoftc.flags &= ~XPT_FLAG_OPEN;

        return(0);
}

static int
xptioctl(dev_t dev, u_long cmd, caddr_t addr, int flag, struct proc *p)
{
        int unit, error;

        error = 0;
        unit = minor(dev) & 0xff;

        /*
         * We only have one transport layer right now.  If someone accesses
         * us via something other than minor number 1, point out their
         * mistake.
         */
        if (unit != 0) {
                printf("xptioctl: got invalid xpt unit %d\n", unit);
                return(ENXIO);
        }

        switch(cmd) {
        /*
         * For the transport layer CAMIOCOMMAND ioctl, we really only want
         * to accept CCB types that don't quite make sense to send through a
         * passthrough driver. XPT_PATH_INQ is an exception to this, as stated
         * in the CAM spec.
         */
        case CAMIOCOMMAND: {
                union ccb *ccb;
                union ccb *inccb;

                inccb = (union ccb *)addr;

                switch(inccb->ccb_h.func_code) {
                case XPT_SCAN_BUS:
                case XPT_RESET_BUS:
                        if ((inccb->ccb_h.target_id != CAM_TARGET_WILDCARD)
                         || (inccb->ccb_h.target_lun != CAM_LUN_WILDCARD)) {
                                error = EINVAL;
                                break;
                        }
                        /* FALLTHROUGH */
                case XPT_PATH_INQ:
                case XPT_ENG_INQ:
                case XPT_SCAN_LUN:

                        ccb = xpt_alloc_ccb();

                        /*
                         * Create a path using the bus, target, and lun the
                         * user passed in.
                         */
                        if (xpt_create_path(&ccb->ccb_h.path, xpt_periph,
                                            inccb->ccb_h.path_id,
                                            inccb->ccb_h.target_id,
                                            inccb->ccb_h.target_lun) !=
                                            CAM_REQ_CMP){
                                error = EINVAL;
                                xpt_free_ccb(ccb);
                                break;
                        }
                        /* Ensure all of our fields are correct */
                        xpt_setup_ccb(&ccb->ccb_h, ccb->ccb_h.path,
                                      inccb->ccb_h.pinfo.priority);
                        xpt_merge_ccb(ccb, inccb);
                        ccb->ccb_h.cbfcnp = xptdone;
                        cam_periph_runccb(ccb, NULL, 0, 0, NULL);
                        bcopy(ccb, inccb, sizeof(union ccb));
                        xpt_free_path(ccb->ccb_h.path);
                        xpt_free_ccb(ccb);
                        break;

                case XPT_DEBUG: {
                        union ccb ccb;

                        /*
                         * This is an immediate CCB, so it's okay to
                         * allocate it on the stack.
                         */

                        /*
                         * Create a path using the bus, target, and lun the
                         * user passed in.
                         */
                        if (xpt_create_path(&ccb.ccb_h.path, xpt_periph,
                                            inccb->ccb_h.path_id,
                                            inccb->ccb_h.target_id,
                                            inccb->ccb_h.target_lun) !=
                                            CAM_REQ_CMP){
                                error = EINVAL;
                                break;
                        }
                        /* Ensure all of our fields are correct */
                        xpt_setup_ccb(&ccb.ccb_h, ccb.ccb_h.path,
                                      inccb->ccb_h.pinfo.priority);
                        xpt_merge_ccb(&ccb, inccb);
                        ccb.ccb_h.cbfcnp = xptdone;
                        xpt_action(&ccb);
                        bcopy(&ccb, inccb, sizeof(union ccb));
                        xpt_free_path(ccb.ccb_h.path);
                        break;

                }
                case XPT_DEV_MATCH: {
                        struct cam_periph_map_info mapinfo;
                        struct cam_path *old_path;

                        /*
                         * We can't deal with physical addresses for this
                         * type of transaction.
                         */
                        if (inccb->ccb_h.flags & CAM_DATA_PHYS) {
                                error = EINVAL;
                                break;
                        }

                        /*
                         * Save this in case the caller had it set to
                         * something in particular.
                         */
                        old_path = inccb->ccb_h.path;

                        /*
                         * We really don't need a path for the matching
                         * code.  The path is needed because of the
                         * debugging statements in xpt_action().  They
                         * assume that the CCB has a valid path.
                         */
                        inccb->ccb_h.path = xpt_periph->path;

                        bzero(&mapinfo, sizeof(mapinfo));

                        /*
                         * Map the pattern and match buffers into kernel
                         * virtual address space.
                         */
                        error = cam_periph_mapmem(inccb, &mapinfo);

                        if (error) {
                                inccb->ccb_h.path = old_path;
                                break;
                        }

                        /*
                         * This is an immediate CCB, we can send it on directly.
                         */
                        xpt_action(inccb);

                        /*
                         * Map the buffers back into user space.
                         */
                        cam_periph_unmapmem(inccb, &mapinfo);

                        inccb->ccb_h.path = old_path;

                        error = 0;
                        break;
                }
                default:
                        error = ENOTSUP;
                        break;
                }
                break;
        }
        /*
         * This is the getpassthru ioctl. It takes a XPT_GDEVLIST ccb as input,
         * with the periphal driver name and unit name filled in.  The other
         * fields don't really matter as input.  The passthrough driver name
         * ("pass"), and unit number are passed back in the ccb.  The current
         * device generation number, and the index into the device peripheral
         * driver list, and the status are also passed back.  Note that
         * since we do everything in one pass, unlike the XPT_GDEVLIST ccb,
         * we never return a status of CAM_GDEVLIST_LIST_CHANGED.  It is
         * (or rather should be) impossible for the device peripheral driver
         * list to change since we look at the whole thing in one pass, and
         * we do it with splcam protection.
         * 
         */
        case CAMGETPASSTHRU: {
                union ccb *ccb;
                struct cam_periph *periph;
                struct periph_driver **p_drv;
                char   *name;
                int unit;
                int cur_generation;
                int base_periph_found;
                int splbreaknum;
                int s;

                ccb = (union ccb *)addr;
                unit = ccb->cgdl.unit_number;
                name = ccb->cgdl.periph_name;
                /*
                 * Every 100 devices, we want to drop our spl protection to
                 * give the software interrupt handler a chance to run.
                 * Most systems won't run into this check, but this should
                 * avoid starvation in the software interrupt handler in
                 * large systems.
                 */
                splbreaknum = 100;

                ccb = (union ccb *)addr;

                base_periph_found = 0;

                /*
                 * Sanity check -- make sure we don't get a null peripheral
                 * driver name.
                 */
                if (*ccb->cgdl.periph_name == '\0') {
                        error = EINVAL;
                        break;
                }

                /* Keep the list from changing while we traverse it */
                s = splcam();
ptstartover:
                cur_generation = xsoftc.generation;

                /* first find our driver in the list of drivers */
                for (p_drv = (struct periph_driver **)periphdriver_set.ls_items;
                     *p_drv != NULL; p_drv++)
                        if (strcmp((*p_drv)->driver_name, name) == 0)
                                break;

                if (*p_drv == NULL) {
                        splx(s);
                        ccb->ccb_h.status = CAM_REQ_CMP_ERR;
                        ccb->cgdl.status = CAM_GDEVLIST_ERROR;
                        *ccb->cgdl.periph_name = '\0';
                        ccb->cgdl.unit_number = 0;
                        error = ENOENT;
                        break;
                }       

                /*
                 * Run through every peripheral instance of this driver
                 * and check to see whether it matches the unit passed
                 * in by the user.  If it does, get out of the loops and
                 * find the passthrough driver associated with that
                 * peripheral driver.
                 */
                for (periph = TAILQ_FIRST(&(*p_drv)->units); periph != NULL;
                     periph = TAILQ_NEXT(periph, unit_links)) {

                        if (periph->unit_number == unit) {
                                break;
                        } else if (--splbreaknum == 0) {
                                splx(s);
                                s = splcam();
                                splbreaknum = 100;
                                if (cur_generation != xsoftc.generation)
                                       goto ptstartover;
                        }
                }
                /*
                 * If we found the peripheral driver that the user passed
                 * in, go through all of the peripheral drivers for that
                 * particular device and look for a passthrough driver.
                 */
                if (periph != NULL) {
                        struct cam_ed *device;
                        int i;

                        base_periph_found = 1;
                        device = periph->path->device;
                        for (i = 0, periph = SLIST_FIRST(&device->periphs);
                             periph != NULL;
                             periph = SLIST_NEXT(periph, periph_links), i++) {
                                /*
                                 * Check to see whether we have a
                                 * passthrough device or not. 
                                 */
                                if (strcmp(periph->periph_name, "pass") == 0) {
                                        /*
                                         * Fill in the getdevlist fields.
                                         */
                                        strcpy(ccb->cgdl.periph_name,
                                               periph->periph_name);
                                        ccb->cgdl.unit_number =
                                                periph->unit_number;
                                        if (SLIST_NEXT(periph, periph_links))
                                                ccb->cgdl.status =
                                                        CAM_GDEVLIST_MORE_DEVS;
                                        else
                                                ccb->cgdl.status =
                                                       CAM_GDEVLIST_LAST_DEVICE;
                                        ccb->cgdl.generation =
                                                device->generation;
                                        ccb->cgdl.index = i;
                                        /*
                                         * Fill in some CCB header fields
                                         * that the user may want.
                                         */
                                        ccb->ccb_h.path_id =
                                                periph->path->bus->path_id;
                                        ccb->ccb_h.target_id =
                                                periph->path->target->target_id;
                                        ccb->ccb_h.target_lun =
                                                periph->path->device->lun_id;
                                        ccb->ccb_h.status = CAM_REQ_CMP;
                                        break;
                                }
                        }
                }

                /*
                 * If the periph is null here, one of two things has
                 * happened.  The first possibility is that we couldn't
                 * find the unit number of the particular peripheral driver
                 * that the user is asking about.  e.g. the user asks for
                 * the passthrough driver for "da11".  We find the list of
                 * "da" peripherals all right, but there is no unit 11.
                 * The other possibility is that we went through the list
                 * of peripheral drivers attached to the device structure,
                 * but didn't find one with the name "pass".  Either way,
                 * we return ENOENT, since we couldn't find something.
                 */
                if (periph == NULL) {
                        ccb->ccb_h.status = CAM_REQ_CMP_ERR;
                        ccb->cgdl.status = CAM_GDEVLIST_ERROR;
                        *ccb->cgdl.periph_name = '\0';
                        ccb->cgdl.unit_number = 0;
                        error = ENOENT;
                        /*
                         * It is unfortunate that this is even necessary,
                         * but there are many, many clueless users out there.
                         * If this is true, the user is looking for the
                         * passthrough driver, but doesn't have one in his
                         * kernel.
                         */
                        if (base_periph_found == 1) {
                                printf("xptioctl: pass driver is not in the "
                                       "kernel\n");
                                printf("xptioctl: put \"device pass0\" in "
                                       "your kernel config file\n");
                        }
                }
                splx(s);
                break;
                }
        default:
                error = ENOTTY;
                break;
        }

        return(error);
}

static int
cam_module_event_handler(module_t mod, int what, void *arg)
{
        if (what == MOD_LOAD) {
                xpt_init(NULL);
        } else if (what == MOD_UNLOAD) {
                return EBUSY;
        }

        return 0;
}

/* Functions accessed by the peripheral drivers */
static void
xpt_init(dummy)
        void *dummy;
{
        struct cam_sim *xpt_sim;
        struct cam_path *path;
        struct cam_devq *devq;
        cam_status status;

        TAILQ_INIT(&xpt_busses);
        TAILQ_INIT(&cam_bioq);
        TAILQ_INIT(&cam_netq);
        SLIST_INIT(&ccb_freeq);
        STAILQ_INIT(&highpowerq);

        /*
         * The xpt layer is, itself, the equivelent of a SIM.
         * Allow 16 ccbs in the ccb pool for it.  This should
         * give decent parallelism when we probe busses and
         * perform other XPT functions.
         */
        devq = cam_simq_alloc(16);
        xpt_sim = cam_sim_alloc(xptaction,
                                xptpoll,
                                "xpt",
                                /*softc*/NULL,
                                /*unit*/0,
                                /*max_dev_transactions*/0,
                                /*max_tagged_dev_transactions*/0,
                                devq);
        xpt_max_ccbs = 16;
                                
        xpt_bus_register(xpt_sim, /*bus #*/0);

        /*
         * Looking at the XPT from the SIM layer, the XPT is
         * the equivelent of a peripheral driver.  Allocate
         * a peripheral driver entry for us.
         */
        if ((status = xpt_create_path(&path, NULL, CAM_XPT_PATH_ID,
                                      CAM_TARGET_WILDCARD,
                                      CAM_LUN_WILDCARD)) != CAM_REQ_CMP) {
                printf("xpt_init: xpt_create_path failed with status %#x,"
                       " failing attach\n", status);
                return;
        }

        cam_periph_alloc(xptregister, NULL, NULL, NULL, "xpt", CAM_PERIPH_BIO,
                         path, NULL, 0, NULL);
        xpt_free_path(path);

        xpt_sim->softc = xpt_periph;

        /*
         * Register a callback for when interrupts are enabled.
         */
        xpt_config_hook =
            (struct intr_config_hook *)malloc(sizeof(struct intr_config_hook),
                                              M_TEMP, M_NOWAIT | M_ZERO);
        if (xpt_config_hook == NULL) {
                printf("xpt_init: Cannot malloc config hook "
                       "- failing attach\n");
                return;
        }

        xpt_config_hook->ich_func = xpt_config;
        if (config_intrhook_establish(xpt_config_hook) != 0) {
                free (xpt_config_hook, M_TEMP);
                printf("xpt_init: config_intrhook_establish failed "
                       "- failing attach\n");
        }

        /* Install our software interrupt handlers */
        camnet_ih = sinthand_add("camnet", NULL, camisr, &cam_netq,
                SWI_CAMNET, 0);
        cambio_ih = sinthand_add("cambio", NULL, camisr, &cam_bioq,
                SWI_CAMBIO, 0);
}

static cam_status
xptregister(struct cam_periph *periph, void *arg)
{
        if (periph == NULL) {
                printf("xptregister: periph was NULL!!\n");
                return(CAM_REQ_CMP_ERR);
        }

        periph->softc = NULL;

        xpt_periph = periph;

        return(CAM_REQ_CMP);
}

int32_t
xpt_add_periph(struct cam_periph *periph)
{
        struct cam_ed *device;
        int32_t  status;
        struct periph_list *periph_head;

        device = periph->path->device;

        periph_head = &device->periphs;

        status = CAM_REQ_CMP;

        if (device != NULL) {
                int s;

                /*
                 * Make room for this peripheral
                 * so it will fit in the queue
                 * when it's scheduled to run
                 */
                s = splsoftcam();
                status = camq_resize(&device->drvq,
                                     device->drvq.array_size + 1);

                device->generation++;

                SLIST_INSERT_HEAD(periph_head, periph, periph_links);

                splx(s);
        }

        xsoftc.generation++;

        return (status);
}

void
xpt_remove_periph(struct cam_periph *periph)
{
        struct cam_ed *device;

        device = periph->path->device;

        if (device != NULL) {
                int s;
                struct periph_list *periph_head;

                periph_head = &device->periphs;
                
                /* Release the slot for this peripheral */
                s = splsoftcam();
                camq_resize(&device->drvq, device->drvq.array_size - 1);

                device->generation++;

                SLIST_REMOVE(periph_head, periph, cam_periph, periph_links);

                splx(s);
        }

        xsoftc.generation++;

}

void
xpt_announce_periph(struct cam_periph *periph, char *announce_string)
{
        int s;
        u_int mb;
        struct cam_path *path;
        struct ccb_trans_settings cts;

        path = periph->path;
        /*
         * To ensure that this is printed in one piece,
         * mask out CAM interrupts.
         */
        s = splsoftcam();
        printf("%s%d at %s%d bus %d target %d lun %d\n",
               periph->periph_name, periph->unit_number,
               path->bus->sim->sim_name,
               path->bus->sim->unit_number,
               path->bus->sim->bus_id,
               path->target->target_id,
               path->device->lun_id);
        printf("%s%d: ", periph->periph_name, periph->unit_number);
        scsi_print_inquiry(&path->device->inq_data);
        if ((bootverbose)
         && (path->device->serial_num_len > 0)) {
                /* Don't wrap the screen  - print only the first 60 chars */
                printf("%s%d: Serial Number %.60s\n", periph->periph_name,
                       periph->unit_number, path->device->serial_num);
        }
        xpt_setup_ccb(&cts.ccb_h, path, /*priority*/1);
        cts.ccb_h.func_code = XPT_GET_TRAN_SETTINGS;
        cts.flags = CCB_TRANS_CURRENT_SETTINGS;
        xpt_action((union ccb*)&cts);
        if (cts.ccb_h.status == CAM_REQ_CMP) {
                u_int speed;
                u_int freq;

                if ((cts.valid & CCB_TRANS_SYNC_OFFSET_VALID) != 0
                  && cts.sync_offset != 0) {
                        freq = scsi_calc_syncsrate(cts.sync_period);
                        speed = freq;
                } else {
                        struct ccb_pathinq cpi;

                        /* Ask the SIM for its base transfer speed */
                        xpt_setup_ccb(&cpi.ccb_h, path, /*priority*/1);
                        cpi.ccb_h.func_code = XPT_PATH_INQ;
                        xpt_action((union ccb *)&cpi);

                        speed = cpi.base_transfer_speed;
                        freq = 0;
                }
                if ((cts.valid & CCB_TRANS_BUS_WIDTH_VALID) != 0)
                        speed *= (0x01 << cts.bus_width);
                mb = speed / 1000;
                if (mb > 0)
                        printf("%s%d: %d.%03dMB/s transfers",
                               periph->periph_name, periph->unit_number,
                               mb, speed % 1000);
                else
                        printf("%s%d: %dKB/s transfers", periph->periph_name,
                               periph->unit_number, speed);
                if ((cts.valid & CCB_TRANS_SYNC_OFFSET_VALID) != 0
                 && cts.sync_offset != 0) {
                        printf(" (%d.%03dMHz, offset %d", freq / 1000,
                               freq % 1000, cts.sync_offset);
                }
                if ((cts.valid & CCB_TRANS_BUS_WIDTH_VALID) != 0
                 && cts.bus_width > 0) {
                        if ((cts.valid & CCB_TRANS_SYNC_OFFSET_VALID) != 0
                         && cts.sync_offset != 0) {
                                printf(", ");
                        } else {
                                printf(" (");
                        }
                        printf("%dbit)", 8 * (0x01 << cts.bus_width));
                } else if ((cts.valid & CCB_TRANS_SYNC_OFFSET_VALID) != 0
                        && cts.sync_offset != 0) {
                        printf(")");
                }

                if (path->device->inq_flags & SID_CmdQue
                 || path->device->flags & CAM_DEV_TAG_AFTER_COUNT) {
                        printf(", Tagged Queueing Enabled");
                }

                printf("\n");
        } else if (path->device->inq_flags & SID_CmdQue
                || path->device->flags & CAM_DEV_TAG_AFTER_COUNT) {
                printf("%s%d: Tagged Queueing Enabled\n",
                       periph->periph_name, periph->unit_number);
        }

        /*
         * We only want to print the caller's announce string if they've
         * passed one in..
         */
        if (announce_string != NULL)
                printf("%s%d: %s\n", periph->periph_name,
                       periph->unit_number, announce_string);
        splx(s);
}


static dev_match_ret
xptbusmatch(struct dev_match_pattern *patterns, int num_patterns,
            struct cam_eb *bus)
{
        dev_match_ret retval;
        int i;

        retval = DM_RET_NONE;

        /*
         * If we aren't given something to match against, that's an error.
         */
        if (bus == NULL)
                return(DM_RET_ERROR);

        /*
         * If there are no match entries, then this bus matches no
         * matter what.
         */
        if ((patterns == NULL) || (num_patterns == 0))
                return(DM_RET_DESCEND | DM_RET_COPY);

        for (i = 0; i < num_patterns; i++) {
                struct bus_match_pattern *cur_pattern;

                /*
                 * If the pattern in question isn't for a bus node, we
                 * aren't interested.  However, we do indicate to the
                 * calling routine that we should continue descending the
                 * tree, since the user wants to match against lower-level
                 * EDT elements.
                 */
                if (patterns[i].type != DEV_MATCH_BUS) {
                        if ((retval & DM_RET_ACTION_MASK) == DM_RET_NONE)
                                retval |= DM_RET_DESCEND;
                        continue;
                }

                cur_pattern = &patterns[i].pattern.bus_pattern;

                /*
                 * If they want to match any bus node, we give them any
                 * device node.
                 */
                if (cur_pattern->flags == BUS_MATCH_ANY) {
                        /* set the copy flag */
                        retval |= DM_RET_COPY;

                        /*
                         * If we've already decided on an action, go ahead
                         * and return.
                         */
                        if ((retval & DM_RET_ACTION_MASK) != DM_RET_NONE)
                                return(retval);
                }

                /*
                 * Not sure why someone would do this...
                 */
                if (cur_pattern->flags == BUS_MATCH_NONE)
                        continue;

                if (((cur_pattern->flags & BUS_MATCH_PATH) != 0)
                 && (cur_pattern->path_id != bus->path_id))
                        continue;

                if (((cur_pattern->flags & BUS_MATCH_BUS_ID) != 0)
                 && (cur_pattern->bus_id != bus->sim->bus_id))
                        continue;

                if (((cur_pattern->flags & BUS_MATCH_UNIT) != 0)
                 && (cur_pattern->unit_number != bus->sim->unit_number))
                        continue;

                if (((cur_pattern->flags & BUS_MATCH_NAME) != 0)
                 && (strncmp(cur_pattern->dev_name, bus->sim->sim_name,
                             DEV_IDLEN) != 0))
                        continue;

                /*
                 * If we get to this point, the user definitely wants 
                 * information on this bus.  So tell the caller to copy the
                 * data out.
                 */
                retval |= DM_RET_COPY;

                /*
                 * If the return action has been set to descend, then we
                 * know that we've already seen a non-bus matching
                 * expression, therefore we need to further descend the tree.
                 * This won't change by continuing around the loop, so we
                 * go ahead and return.  If we haven't seen a non-bus
                 * matching expression, we keep going around the loop until
                 * we exhaust the matching expressions.  We'll set the stop
                 * flag once we fall out of the loop.
                 */
                if ((retval & DM_RET_ACTION_MASK) == DM_RET_DESCEND)
                        return(retval);
        }

        /*
         * If the return action hasn't been set to descend yet, that means
         * we haven't seen anything other than bus matching patterns.  So
         * tell the caller to stop descending the tree -- the user doesn't
         * want to match against lower level tree elements.
         */
        if ((retval & DM_RET_ACTION_MASK) == DM_RET_NONE)
                retval |= DM_RET_STOP;

        return(retval);
}

static dev_match_ret
xptdevicematch(struct dev_match_pattern *patterns, int num_patterns,
               struct cam_ed *device)
{
        dev_match_ret retval;
        int i;

        retval = DM_RET_NONE;

        /*
         * If we aren't given something to match against, that's an error.
         */
        if (device == NULL)
                return(DM_RET_ERROR);

        /*
         * If there are no match entries, then this device matches no
         * matter what.
         */
        if ((patterns == NULL) || (patterns == 0))
                return(DM_RET_DESCEND | DM_RET_COPY);

        for (i = 0; i < num_patterns; i++) {
                struct device_match_pattern *cur_pattern;

                /*
                 * If the pattern in question isn't for a device node, we
                 * aren't interested.
                 */
                if (patterns[i].type != DEV_MATCH_DEVICE) {
                        if ((patterns[i].type == DEV_MATCH_PERIPH)
                         && ((retval & DM_RET_ACTION_MASK) == DM_RET_NONE))
                                retval |= DM_RET_DESCEND;
                        continue;
                }

                cur_pattern = &patterns[i].pattern.device_pattern;

                /*
                 * If they want to match any device node, we give them any
                 * device node.
                 */
                if (cur_pattern->flags == DEV_MATCH_ANY) {
                        /* set the copy flag */
                        retval |= DM_RET_COPY;

                        
                        /*
                         * If we've already decided on an action, go ahead
                         * and return.
                         */
                        if ((retval & DM_RET_ACTION_MASK) != DM_RET_NONE)
                                return(retval);
                }

                /*
                 * Not sure why someone would do this...
                 */
                if (cur_pattern->flags == DEV_MATCH_NONE)
                        continue;

                if (((cur_pattern->flags & DEV_MATCH_PATH) != 0)
                 && (cur_pattern->path_id != device->target->bus->path_id))
                        continue;

                if (((cur_pattern->flags & DEV_MATCH_TARGET) != 0)
                 && (cur_pattern->target_id != device->target->target_id))
                        continue;

                if (((cur_pattern->flags & DEV_MATCH_LUN) != 0)
                 && (cur_pattern->target_lun != device->lun_id))
                        continue;

                if (((cur_pattern->flags & DEV_MATCH_INQUIRY) != 0)
                 && (cam_quirkmatch((caddr_t)&device->inq_data,
                                    (caddr_t)&cur_pattern->inq_pat,
                                    1, sizeof(cur_pattern->inq_pat),
                                    scsi_static_inquiry_match) == NULL))
                        continue;

                /*
                 * If we get to this point, the user definitely wants 
                 * information on this device.  So tell the caller to copy
                 * the data out.
                 */
                retval |= DM_RET_COPY;

                /*
                 * If the return action has been set to descend, then we
                 * know that we've already seen a peripheral matching
                 * expression, therefore we need to further descend the tree.
                 * This won't change by continuing around the loop, so we
                 * go ahead and return.  If we haven't seen a peripheral
                 * matching expression, we keep going around the loop until
                 * we exhaust the matching expressions.  We'll set the stop
                 * flag once we fall out of the loop.
                 */
                if ((retval & DM_RET_ACTION_MASK) == DM_RET_DESCEND)
                        return(retval);
        }

        /*
         * If the return action hasn't been set to descend yet, that means
         * we haven't seen any peripheral matching patterns.  So tell the
         * caller to stop descending the tree -- the user doesn't want to
         * match against lower level tree elements.
         */
        if ((retval & DM_RET_ACTION_MASK) == DM_RET_NONE)
                retval |= DM_RET_STOP;

        return(retval);
}

/*
 * Match a single peripheral against any number of match patterns.
 */
static dev_match_ret
xptperiphmatch(struct dev_match_pattern *patterns, int num_patterns,
               struct cam_periph *periph)
{
        dev_match_ret retval;
        int i;

        /*
         * If we aren't given something to match against, that's an error.
         */
        if (periph == NULL)
                return(DM_RET_ERROR);

        /*
         * If there are no match entries, then this peripheral matches no
         * matter what.
         */
        if ((patterns == NULL) || (num_patterns == 0))
                return(DM_RET_STOP | DM_RET_COPY);

        /*
         * There aren't any nodes below a peripheral node, so there's no
         * reason to descend the tree any further.
         */
        retval = DM_RET_STOP;

        for (i = 0; i < num_patterns; i++) {
                struct periph_match_pattern *cur_pattern;

                /*
                 * If the pattern in question isn't for a peripheral, we
                 * aren't interested.
                 */
                if (patterns[i].type != DEV_MATCH_PERIPH)
                        continue;

                cur_pattern = &patterns[i].pattern.periph_pattern;

                /*
                 * If they want to match on anything, then we will do so.
                 */
                if (cur_pattern->flags == PERIPH_MATCH_ANY) {
                        /* set the copy flag */
                        retval |= DM_RET_COPY;

                        /*
                         * We've already set the return action to stop,
                         * since there are no nodes below peripherals in
                         * the tree.
                         */
                        return(retval);
                }

                /*
                 * Not sure why someone would do this...
                 */
                if (cur_pattern->flags == PERIPH_MATCH_NONE)
                        continue;

                if (((cur_pattern->flags & PERIPH_MATCH_PATH) != 0)
                 && (cur_pattern->path_id != periph->path->bus->path_id))
                        continue;

                /*
                 * For the target and lun id's, we have to make sure the
                 * target and lun pointers aren't NULL.  The xpt peripheral
                 * has a wildcard target and device.
                 */
                if (((cur_pattern->flags & PERIPH_MATCH_TARGET) != 0)
                 && ((periph->path->target == NULL)
                 ||(cur_pattern->target_id != periph->path->target->target_id)))
                        continue;

                if (((cur_pattern->flags & PERIPH_MATCH_LUN) != 0)
                 && ((periph->path->device == NULL)
                 || (cur_pattern->target_lun != periph->path->device->lun_id)))
                        continue;

                if (((cur_pattern->flags & PERIPH_MATCH_UNIT) != 0)
                 && (cur_pattern->unit_number != periph->unit_number))
                        continue;

                if (((cur_pattern->flags & PERIPH_MATCH_NAME) != 0)
                 && (strncmp(cur_pattern->periph_name, periph->periph_name,
                             DEV_IDLEN) != 0))
                        continue;

                /*
                 * If we get to this point, the user definitely wants 
                 * information on this peripheral.  So tell the caller to
                 * copy the data out.
                 */
                retval |= DM_RET_COPY;

                /*
                 * The return action has already been set to stop, since
                 * peripherals don't have any nodes below them in the EDT.
                 */
                return(retval);
        }

        /*
         * If we get to this point, the peripheral that was passed in
         * doesn't match any of the patterns.
         */
        return(retval);
}

static int
xptedtbusfunc(struct cam_eb *bus, void *arg)
{
        struct ccb_dev_match *cdm;
        dev_match_ret retval;

        cdm = (struct ccb_dev_match *)arg;

        /*
         * If our position is for something deeper in the tree, that means
         * that we've already seen this node.  So, we keep going down.
         */
        if ((cdm->pos.position_type & CAM_DEV_POS_BUS)
         && (cdm->pos.cookie.bus == bus)
         && (cdm->pos.position_type & CAM_DEV_POS_TARGET)
         && (cdm->pos.cookie.target != NULL))
                retval = DM_RET_DESCEND;
        else
                retval = xptbusmatch(cdm->patterns, cdm->num_patterns, bus);

        /*
         * If we got an error, bail out of the search.
         */
        if ((retval & DM_RET_ACTION_MASK) == DM_RET_ERROR) {
                cdm->status = CAM_DEV_MATCH_ERROR;
                return(0);
        }

        /*
         * If the copy flag is set, copy this bus out.
         */
        if (retval & DM_RET_COPY) {
                int spaceleft, j;

                spaceleft = cdm->match_buf_len - (cdm->num_matches *
                        sizeof(struct dev_match_result));

                /*
                 * If we don't have enough space to put in another
                 * match result, save our position and tell the
                 * user there are more devices to check.
                 */
                if (spaceleft < sizeof(struct dev_match_result)) {
                        bzero(&cdm->pos, sizeof(cdm->pos));
                        cdm->pos.position_type = 
                                CAM_DEV_POS_EDT | CAM_DEV_POS_BUS;

                        cdm->pos.cookie.bus = bus;
                        cdm->pos.generations[CAM_BUS_GENERATION]=
                                bus_generation;
                        cdm->status = CAM_DEV_MATCH_MORE;
                        return(0);
                }
                j = cdm->num_matches;
                cdm->num_matches++;
                cdm->matches[j].type = DEV_MATCH_BUS;
                cdm->matches[j].result.bus_result.path_id = bus->path_id;
                cdm->matches[j].result.bus_result.bus_id = bus->sim->bus_id;
                cdm->matches[j].result.bus_result.unit_number =
                        bus->sim->unit_number;
                strncpy(cdm->matches[j].result.bus_result.dev_name,
                        bus->sim->sim_name, DEV_IDLEN);
        }

        /*
         * If the user is only interested in busses, there's no
         * reason to descend to the next level in the tree.
         */
        if ((retval & DM_RET_ACTION_MASK) == DM_RET_STOP)
                return(1);

        /*
         * If there is a target generation recorded, check it to
         * make sure the target list hasn't changed.
         */
        if ((cdm->pos.position_type & CAM_DEV_POS_BUS)
         && (bus == cdm->pos.cookie.bus)
         && (cdm->pos.position_type & CAM_DEV_POS_TARGET)
         && (cdm->pos.generations[CAM_TARGET_GENERATION] != 0)
         && (cdm->pos.generations[CAM_TARGET_GENERATION] !=
             bus->generation)) {
                cdm->status = CAM_DEV_MATCH_LIST_CHANGED;
                return(0);
        }

        if ((cdm->pos.position_type & CAM_DEV_POS_BUS)
         && (cdm->pos.cookie.bus == bus)
         && (cdm->pos.position_type & CAM_DEV_POS_TARGET)
         && (cdm->pos.cookie.target != NULL))
                return(xpttargettraverse(bus,
                                        (struct cam_et *)cdm->pos.cookie.target,
                                         xptedttargetfunc, arg));
        else
                return(xpttargettraverse(bus, NULL, xptedttargetfunc, arg));
}

static int
xptedttargetfunc(struct cam_et *target, void *arg)
{
        struct ccb_dev_match *cdm;

        cdm = (struct ccb_dev_match *)arg;

        /*
         * If there is a device list generation recorded, check it to
         * make sure the device list hasn't changed.
         */
        if ((cdm->pos.position_type & CAM_DEV_POS_BUS)
         && (cdm->pos.cookie.bus == target->bus)
         && (cdm->pos.position_type & CAM_DEV_POS_TARGET)
         && (cdm->pos.cookie.target == target)
         && (cdm->pos.position_type & CAM_DEV_POS_DEVICE)
         && (cdm->pos.generations[CAM_DEV_GENERATION] != 0)
         && (cdm->pos.generations[CAM_DEV_GENERATION] !=
             target->generation)) {
                cdm->status = CAM_DEV_MATCH_LIST_CHANGED;
                return(0);
        }

        if ((cdm->pos.position_type & CAM_DEV_POS_BUS)
         && (cdm->pos.cookie.bus == target->bus)
         && (cdm->pos.position_type & CAM_DEV_POS_TARGET)
         && (cdm->pos.cookie.target == target)
         && (cdm->pos.position_type & CAM_DEV_POS_DEVICE)
         && (cdm->pos.cookie.device != NULL))
                return(xptdevicetraverse(target,
                                        (struct cam_ed *)cdm->pos.cookie.device,
                                         xptedtdevicefunc, arg));
        else
                return(xptdevicetraverse(target, NULL, xptedtdevicefunc, arg));
}

static int
xptedtdevicefunc(struct cam_ed *device, void *arg)
{

        struct ccb_dev_match *cdm;
        dev_match_ret retval;

        cdm = (struct ccb_dev_match *)arg;

        /*
         * If our position is for something deeper in the tree, that means
         * that we've already seen this node.  So, we keep going down.
         */
        if ((cdm->pos.position_type & CAM_DEV_POS_DEVICE)
         && (cdm->pos.cookie.device == device)
         && (cdm->pos.position_type & CAM_DEV_POS_PERIPH)
         && (cdm->pos.cookie.periph != NULL))
                retval = DM_RET_DESCEND;
        else
                retval = xptdevicematch(cdm->patterns, cdm->num_patterns,
                                        device);

        if ((retval & DM_RET_ACTION_MASK) == DM_RET_ERROR) {
                cdm->status = CAM_DEV_MATCH_ERROR;
                return(0);
        }

        /*
         * If the copy flag is set, copy this device out.
         */
        if (retval & DM_RET_COPY) {
                int spaceleft, j;

                spaceleft = cdm->match_buf_len - (cdm->num_matches *
                        sizeof(struct dev_match_result));

                /*
                 * If we don't have enough space to put in another
                 * match result, save our position and tell the
                 * user there are more devices to check.
                 */
                if (spaceleft < sizeof(struct dev_match_result)) {
                        bzero(&cdm->pos, sizeof(cdm->pos));
                        cdm->pos.position_type = 
                                CAM_DEV_POS_EDT | CAM_DEV_POS_BUS |
                                CAM_DEV_POS_TARGET | CAM_DEV_POS_DEVICE;

                        cdm->pos.cookie.bus = device->target->bus;
                        cdm->pos.generations[CAM_BUS_GENERATION]=
                                bus_generation;
                        cdm->pos.cookie.target = device->target;
                        cdm->pos.generations[CAM_TARGET_GENERATION] =
                                device->target->bus->generation;
                        cdm->pos.cookie.device = device;
                        cdm->pos.generations[CAM_DEV_GENERATION] = 
                                device->target->generation;
                        cdm->status = CAM_DEV_MATCH_MORE;
                        return(0);
                }
                j = cdm->num_matches;
                cdm->num_matches++;
                cdm->matches[j].type = DEV_MATCH_DEVICE;
                cdm->matches[j].result.device_result.path_id =
                        device->target->bus->path_id;
                cdm->matches[j].result.device_result.target_id =
                        device->target->target_id;
                cdm->matches[j].result.device_result.target_lun =
                        device->lun_id;
                bcopy(&device->inq_data,
                      &cdm->matches[j].result.device_result.inq_data,
                      sizeof(struct scsi_inquiry_data));

                /* Let the user know whether this device is unconfigured */
                if (device->flags & CAM_DEV_UNCONFIGURED)
                        cdm->matches[j].result.device_result.flags =
                                DEV_RESULT_UNCONFIGURED;
                else
                        cdm->matches[j].result.device_result.flags =
                                DEV_RESULT_NOFLAG;
        }

        /*
         * If the user isn't interested in peripherals, don't descend
         * the tree any further.
         */
        if ((retval & DM_RET_ACTION_MASK) == DM_RET_STOP)
                return(1);

        /*
         * If there is a peripheral list generation recorded, make sure
         * it hasn't changed.
         */
        if ((cdm->pos.position_type & CAM_DEV_POS_BUS)
         && (device->target->bus == cdm->pos.cookie.bus)
         && (cdm->pos.position_type & CAM_DEV_POS_TARGET)
         && (device->target == cdm->pos.cookie.target)
         && (cdm->pos.position_type & CAM_DEV_POS_DEVICE)
         && (device == cdm->pos.cookie.device)
         && (cdm->pos.position_type & CAM_DEV_POS_PERIPH)
         && (cdm->pos.generations[CAM_PERIPH_GENERATION] != 0)
         && (cdm->pos.generations[CAM_PERIPH_GENERATION] !=
             device->generation)){
                cdm->status = CAM_DEV_MATCH_LIST_CHANGED;
                return(0);
        }

        if ((cdm->pos.position_type & CAM_DEV_POS_BUS)
         && (cdm->pos.cookie.bus == device->target->bus)
         && (cdm->pos.position_type & CAM_DEV_POS_TARGET)
         && (cdm->pos.cookie.target == device->target)
         && (cdm->pos.position_type & CAM_DEV_POS_DEVICE)
         && (cdm->pos.cookie.device == device)
         && (cdm->pos.position_type & CAM_DEV_POS_PERIPH)
         && (cdm->pos.cookie.periph != NULL))
                return(xptperiphtraverse(device,
                                (struct cam_periph *)cdm->pos.cookie.periph,
                                xptedtperiphfunc, arg));
        else
                return(xptperiphtraverse(device, NULL, xptedtperiphfunc, arg));
}

static int
xptedtperiphfunc(struct cam_periph *periph, void *arg)
{
        struct ccb_dev_match *cdm;
        dev_match_ret retval;

        cdm = (struct ccb_dev_match *)arg;

        retval = xptperiphmatch(cdm->patterns, cdm->num_patterns, periph);

        if ((retval & DM_RET_ACTION_MASK) == DM_RET_ERROR) {
                cdm->status = CAM_DEV_MATCH_ERROR;
                return(0);
        }

        /*
         * If the copy flag is set, copy this peripheral out.
         */
        if (retval & DM_RET_COPY) {
                int spaceleft, j;

                spaceleft = cdm->match_buf_len - (cdm->num_matches *
                        sizeof(struct dev_match_result));

                /*
                 * If we don't have enough space to put in another
                 * match result, save our position and tell the
                 * user there are more devices to check.
                 */
                if (spaceleft < sizeof(struct dev_match_result)) {
                        bzero(&cdm->pos, sizeof(cdm->pos));
                        cdm->pos.position_type = 
                                CAM_DEV_POS_EDT | CAM_DEV_POS_BUS |
                                CAM_DEV_POS_TARGET | CAM_DEV_POS_DEVICE |
                                CAM_DEV_POS_PERIPH;

                        cdm->pos.cookie.bus = periph->path->bus;
                        cdm->pos.generations[CAM_BUS_GENERATION]=
                                bus_generation;
                        cdm->pos.cookie.target = periph->path->target;
                        cdm->pos.generations[CAM_TARGET_GENERATION] =
                                periph->path->bus->generation;
                        cdm->pos.cookie.device = periph->path->device;
                        cdm->pos.generations[CAM_DEV_GENERATION] = 
                                periph->path->target->generation;
                        cdm->pos.cookie.periph = periph;
                        cdm->pos.generations[CAM_PERIPH_GENERATION] =
                                periph->path->device->generation;
                        cdm->status = CAM_DEV_MATCH_MORE;
                        return(0);
                }

                j = cdm->num_matches;
                cdm->num_matches++;
                cdm->matches[j].type = DEV_MATCH_PERIPH;
                cdm->matches[j].result.periph_result.path_id =
                        periph->path->bus->path_id;
                cdm->matches[j].result.periph_result.target_id =
                        periph->path->target->target_id;
                cdm->matches[j].result.periph_result.target_lun =
                        periph->path->device->lun_id;
                cdm->matches[j].result.periph_result.unit_number =
                        periph->unit_number;
                strncpy(cdm->matches[j].result.periph_result.periph_name,
                        periph->periph_name, DEV_IDLEN);
        }

        return(1);
}

static int
xptedtmatch(struct ccb_dev_match *cdm)
{
        int ret;

        cdm->num_matches = 0;

        /*
         * Check the bus list generation.  If it has changed, the user
         * needs to reset everything and start over.
         */
        if ((cdm->pos.position_type & CAM_DEV_POS_BUS)
         && (cdm->pos.generations[CAM_BUS_GENERATION] != 0)
         && (cdm->pos.generations[CAM_BUS_GENERATION] != bus_generation)) {
                cdm->status = CAM_DEV_MATCH_LIST_CHANGED;
                return(0);
        }

        if ((cdm->pos.position_type & CAM_DEV_POS_BUS)
         && (cdm->pos.cookie.bus != NULL))
                ret = xptbustraverse((struct cam_eb *)cdm->pos.cookie.bus,
                                     xptedtbusfunc, cdm);
        else
                ret = xptbustraverse(NULL, xptedtbusfunc, cdm);

        /*
         * If we get back 0, that means that we had to stop before fully
         * traversing the EDT.  It also means that one of the subroutines
         * has set the status field to the proper value.  If we get back 1,
         * we've fully traversed the EDT and copied out any matching entries.
         */
        if (ret == 1)
                cdm->status = CAM_DEV_MATCH_LAST;

        return(ret);
}

static int
xptplistpdrvfunc(struct periph_driver **pdrv, void *arg)
{
        struct ccb_dev_match *cdm;

        cdm = (struct ccb_dev_match *)arg;

        if ((cdm->pos.position_type & CAM_DEV_POS_PDPTR)
         && (cdm->pos.cookie.pdrv == pdrv)
         && (cdm->pos.position_type & CAM_DEV_POS_PERIPH)
         && (cdm->pos.generations[CAM_PERIPH_GENERATION] != 0)
         && (cdm->pos.generations[CAM_PERIPH_GENERATION] !=
             (*pdrv)->generation)) {
                cdm->status = CAM_DEV_MATCH_LIST_CHANGED;
                return(0);
        }

        if ((cdm->pos.position_type & CAM_DEV_POS_PDPTR)
         && (cdm->pos.cookie.pdrv == pdrv)
         && (cdm->pos.position_type & CAM_DEV_POS_PERIPH)
         && (cdm->pos.cookie.periph != NULL))
                return(xptpdperiphtraverse(pdrv,
                                (struct cam_periph *)cdm->pos.cookie.periph,
                                xptplistperiphfunc, arg));
        else
                return(xptpdperiphtraverse(pdrv, NULL,xptplistperiphfunc, arg));
}

static int
xptplistperiphfunc(struct cam_periph *periph, void *arg)
{
        struct ccb_dev_match *cdm;
        dev_match_ret retval;

        cdm = (struct ccb_dev_match *)arg;

        retval = xptperiphmatch(cdm->patterns, cdm->num_patterns, periph);

        if ((retval & DM_RET_ACTION_MASK) == DM_RET_ERROR) {
                cdm->status = CAM_DEV_MATCH_ERROR;
                return(0);
        }

        /*
         * If the copy flag is set, copy this peripheral out.
         */
        if (retval & DM_RET_COPY) {
                int spaceleft, j;

                spaceleft = cdm->match_buf_len - (cdm->num_matches *
                        sizeof(struct dev_match_result));

                /*
                 * If we don't have enough space to put in another
                 * match result, save our position and tell the
                 * user there are more devices to check.
                 */
                if (spaceleft < sizeof(struct dev_match_result)) {
                        struct periph_driver **pdrv;

                        pdrv = NULL;
                        bzero(&cdm->pos, sizeof(cdm->pos));
                        cdm->pos.position_type = 
                                CAM_DEV_POS_PDRV | CAM_DEV_POS_PDPTR |
                                CAM_DEV_POS_PERIPH;

                        /*
                         * This may look a bit non-sensical, but it is
                         * actually quite logical.  There are very few
                         * peripheral drivers, and bloating every peripheral
                         * structure with a pointer back to its parent
                         * peripheral driver linker set entry would cost
                         * more in the long run than doing this quick lookup.
                         */
                        for (pdrv =
                             (struct periph_driver **)periphdriver_set.ls_items;
                             *pdrv != NULL; pdrv++) {
                                if (strcmp((*pdrv)->driver_name,
                                    periph->periph_name) == 0)
                                        break;
                        }

                        if (pdrv == NULL) {
                                cdm->status = CAM_DEV_MATCH_ERROR;
                                return(0);
                        }

                        cdm->pos.cookie.pdrv = pdrv;
                        /*
                         * The periph generation slot does double duty, as
                         * does the periph pointer slot.  They are used for
                         * both edt and pdrv lookups and positioning.
                         */
                        cdm->pos.cookie.periph = periph;
                        cdm->pos.generations[CAM_PERIPH_GENERATION] =
                                (*pdrv)->generation;
                        cdm->status = CAM_DEV_MATCH_MORE;
                        return(0);
                }

                j = cdm->num_matches;
                cdm->num_matches++;
                cdm->matches[j].type = DEV_MATCH_PERIPH;
                cdm->matches[j].result.periph_result.path_id =
                        periph->path->bus->path_id;

                /*
                 * The transport layer peripheral doesn't have a target or
                 * lun.
                 */
                if (periph->path->target)
                        cdm->matches[j].result.periph_result.target_id =
                                periph->path->target->target_id;
                else
                        cdm->matches[j].result.periph_result.target_id = -1;

                if (periph->path->device)
                        cdm->matches[j].result.periph_result.target_lun =
                                periph->path->device->lun_id;
                else
                        cdm->matches[j].result.periph_result.target_lun = -1;

                cdm->matches[j].result.periph_result.unit_number =
                        periph->unit_number;
                strncpy(cdm->matches[j].result.periph_result.periph_name,
                        periph->periph_name, DEV_IDLEN);
        }

        return(1);
}

static int
xptperiphlistmatch(struct ccb_dev_match *cdm)
{
        int ret;

        cdm->num_matches = 0;

        /*
         * At this point in the edt traversal function, we check the bus
         * list generation to make sure that no busses have been added or
         * removed since the user last sent a XPT_DEV_MATCH ccb through.
         * For the peripheral driver list traversal function, however, we
         * don't have to worry about new peripheral driver types coming or
         * going; they're in a linker set, and therefore can't change
         * without a recompile.
         */

        if ((cdm->pos.position_type & CAM_DEV_POS_PDPTR)
         && (cdm->pos.cookie.pdrv != NULL))
                ret = xptpdrvtraverse(
                                (struct periph_driver **)cdm->pos.cookie.pdrv,
                                xptplistpdrvfunc, cdm);
        else
                ret = xptpdrvtraverse(NULL, xptplistpdrvfunc, cdm);

        /*
         * If we get back 0, that means that we had to stop before fully
         * traversing the peripheral driver tree.  It also means that one of
         * the subroutines has set the status field to the proper value.  If
         * we get back 1, we've fully traversed the EDT and copied out any
         * matching entries.
         */
        if (ret == 1)
                cdm->status = CAM_DEV_MATCH_LAST;

        return(ret);
}

static int
xptbustraverse(struct cam_eb *start_bus, xpt_busfunc_t *tr_func, void *arg)
{
        struct cam_eb *bus, *next_bus;
        int retval;

        retval = 1;

        for (bus = (start_bus ? start_bus : TAILQ_FIRST(&xpt_busses));
             bus != NULL;
             bus = next_bus) {
                next_bus = TAILQ_NEXT(bus, links);

                retval = tr_func(bus, arg);
                if (retval == 0)
                        return(retval);
        }

        return(retval);
}

static int
xpttargettraverse(struct cam_eb *bus, struct cam_et *start_target,
                  xpt_targetfunc_t *tr_func, void *arg)
{
        struct cam_et *target, *next_target;
        int retval;

        retval = 1;
        for (target = (start_target ? start_target :
                       TAILQ_FIRST(&bus->et_entries));
             target != NULL; target = next_target) {

                next_target = TAILQ_NEXT(target, links);

                retval = tr_func(target, arg);

                if (retval == 0)
                        return(retval);
        }

        return(retval);
}

static int
xptdevicetraverse(struct cam_et *target, struct cam_ed *start_device,
                  xpt_devicefunc_t *tr_func, void *arg)
{
        struct cam_ed *device, *next_device;
        int retval;

        retval = 1;
        for (device = (start_device ? start_device :
                       TAILQ_FIRST(&target->ed_entries));
             device != NULL;
             device = next_device) {

                next_device = TAILQ_NEXT(device, links);

                retval = tr_func(device, arg);

                if (retval == 0)
                        return(retval);
        }

        return(retval);
}

static int
xptperiphtraverse(struct cam_ed *device, struct cam_periph *start_periph,
                  xpt_periphfunc_t *tr_func, void *arg)
{
        struct cam_periph *periph, *next_periph;
        int retval;

        retval = 1;

        for (periph = (start_periph ? start_periph :
                       SLIST_FIRST(&device->periphs));
             periph != NULL;
             periph = next_periph) {

                next_periph = SLIST_NEXT(periph, periph_links);

                retval = tr_func(periph, arg);
                if (retval == 0)
                        return(retval);
        }

        return(retval);
}

static int
xptpdrvtraverse(struct periph_driver **start_pdrv,
                xpt_pdrvfunc_t *tr_func, void *arg)
{
        struct periph_driver **pdrv;
        int retval;

        retval = 1;

        /*
         * We don't traverse the peripheral driver list like we do the
         * other lists, because it is a linker set, and therefore cannot be
         * changed during runtime.  If the peripheral driver list is ever
         * re-done to be something other than a linker set (i.e. it can
         * change while the system is running), the list traversal should
         * be modified to work like the other traversal functions.
         */
        for (pdrv = (start_pdrv ? start_pdrv :
             (struct periph_driver **)periphdriver_set.ls_items);
             *pdrv != NULL; pdrv++) {
                retval = tr_func(pdrv, arg);

                if (retval == 0)
                        return(retval);
        }

        return(retval);
}

static int
xptpdperiphtraverse(struct periph_driver **pdrv,
                    struct cam_periph *start_periph,
                    xpt_periphfunc_t *tr_func, void *arg)
{
        struct cam_periph *periph, *next_periph;
        int retval;

        retval = 1;

        for (periph = (start_periph ? start_periph :
             TAILQ_FIRST(&(*pdrv)->units)); periph != NULL;
             periph = next_periph) {

                next_periph = TAILQ_NEXT(periph, unit_links);

                retval = tr_func(periph, arg);
                if (retval == 0)
                        return(retval);
        }
        return(retval);
}

static int
xptdefbusfunc(struct cam_eb *bus, void *arg)
{
        struct xpt_traverse_config *tr_config;

        tr_config = (struct xpt_traverse_config *)arg;

        if (tr_config->depth == XPT_DEPTH_BUS) {
                xpt_busfunc_t *tr_func;

                tr_func = (xpt_busfunc_t *)tr_config->tr_func;

                return(tr_func(bus, tr_config->tr_arg));
        } else
                return(xpttargettraverse(bus, NULL, xptdeftargetfunc, arg));
}

static int
xptdeftargetfunc(struct cam_et *target, void *arg)
{
        struct xpt_traverse_config *tr_config;

        tr_config = (struct xpt_traverse_config *)arg;

        if (tr_config->depth == XPT_DEPTH_TARGET) {
                xpt_targetfunc_t *tr_func;

                tr_func = (xpt_targetfunc_t *)tr_config->tr_func;

                return(tr_func(target, tr_config->tr_arg));
        } else
                return(xptdevicetraverse(target, NULL, xptdefdevicefunc, arg));
}

static int
xptdefdevicefunc(struct cam_ed *device, void *arg)
{
        struct xpt_traverse_config *tr_config;

        tr_config = (struct xpt_traverse_config *)arg;

        if (tr_config->depth == XPT_DEPTH_DEVICE) {
                xpt_devicefunc_t *tr_func;

                tr_func = (xpt_devicefunc_t *)tr_config->tr_func;

                return(tr_func(device, tr_config->tr_arg));
        } else
                return(xptperiphtraverse(device, NULL, xptdefperiphfunc, arg));
}

static int
xptdefperiphfunc(struct cam_periph *periph, void *arg)
{
        struct xpt_traverse_config *tr_config;
        xpt_periphfunc_t *tr_func;

        tr_config = (struct xpt_traverse_config *)arg;

        tr_func = (xpt_periphfunc_t *)tr_config->tr_func;

        /*
         * Unlike the other default functions, we don't check for depth
         * here.  The peripheral driver level is the last level in the EDT,
         * so if we're here, we should execute the function in question.
         */
        return(tr_func(periph, tr_config->tr_arg));
}

/*
 * Execute the given function for every bus in the EDT.
 */
static int
xpt_for_all_busses(xpt_busfunc_t *tr_func, void *arg)
{
        struct xpt_traverse_config tr_config;

        tr_config.depth = XPT_DEPTH_BUS;
        tr_config.tr_func = tr_func;
        tr_config.tr_arg = arg;

        return(xptbustraverse(NULL, xptdefbusfunc, &tr_config));
}

#ifdef notusedyet
/*
 * Execute the given function for every target in the EDT.
 */
static int
xpt_for_all_targets(xpt_targetfunc_t *tr_func, void *arg)
{
        struct xpt_traverse_config tr_config;

        tr_config.depth = XPT_DEPTH_TARGET;
        tr_config.tr_func = tr_func;
        tr_config.tr_arg = arg;

        return(xptbustraverse(NULL, xptdefbusfunc, &tr_config));
}
#endif /* notusedyet */

/*
 * Execute the given function for every device in the EDT.
 */
static int
xpt_for_all_devices(xpt_devicefunc_t *tr_func, void *arg)
{
        struct xpt_traverse_config tr_config;

        tr_config.depth = XPT_DEPTH_DEVICE;
        tr_config.tr_func = tr_func;
        tr_config.tr_arg = arg;

        return(xptbustraverse(NULL, xptdefbusfunc, &tr_config));
}

#ifdef notusedyet
/*
 * Execute the given function for every peripheral in the EDT.
 */
static int
xpt_for_all_periphs(xpt_periphfunc_t *tr_func, void *arg)
{
        struct xpt_traverse_config tr_config;

        tr_config.depth = XPT_DEPTH_PERIPH;
        tr_config.tr_func = tr_func;
        tr_config.tr_arg = arg;

        return(xptbustraverse(NULL, xptdefbusfunc, &tr_config));
}
#endif /* notusedyet */

static int
xptsetasyncfunc(struct cam_ed *device, void *arg)
{
        struct cam_path path;
        struct ccb_getdev cgd;
        struct async_node *cur_entry;

        cur_entry = (struct async_node *)arg;

        /*
         * Don't report unconfigured devices (Wildcard devs,
         * devices only for target mode, device instances
         * that have been invalidated but are waiting for
         * their last reference count to be released).
         */
        if ((device->flags & CAM_DEV_UNCONFIGURED) != 0)
                return (1);

        xpt_compile_path(&path,
                         NULL,
                         device->target->bus->path_id,
                         device->target->target_id,
                         device->lun_id);
        xpt_setup_ccb(&cgd.ccb_h, &path, /*priority*/1);
        cgd.ccb_h.func_code = XPT_GDEV_TYPE;
        xpt_action((union ccb *)&cgd);
        cur_entry->callback(cur_entry->callback_arg,
                            AC_FOUND_DEVICE,
                            &path, &cgd);
        xpt_release_path(&path);

        return(1);
}

static int
xptsetasyncbusfunc(struct cam_eb *bus, void *arg)
{
        struct cam_path path;
        struct ccb_pathinq cpi;
        struct async_node *cur_entry;

        cur_entry = (struct async_node *)arg;

        xpt_compile_path(&path, /*periph*/NULL,
                         bus->sim->path_id,
                         CAM_TARGET_WILDCARD,
                         CAM_LUN_WILDCARD);
        xpt_setup_ccb(&cpi.ccb_h, &path, /*priority*/1);
        cpi.ccb_h.func_code = XPT_PATH_INQ;
        xpt_action((union ccb *)&cpi);
        cur_entry->callback(cur_entry->callback_arg,
                            AC_PATH_REGISTERED,
                            &path, &cpi);
        xpt_release_path(&path);

        return(1);
}

void
xpt_action(union ccb *start_ccb)
{
        int iopl;

        CAM_DEBUG(start_ccb->ccb_h.path, CAM_DEBUG_TRACE, ("xpt_action\n"));

        start_ccb->ccb_h.status = CAM_REQ_INPROG;

        iopl = splsoftcam();
        switch (start_ccb->ccb_h.func_code) {
        case XPT_SCSI_IO:
        {
#ifdef CAMDEBUG
                char cdb_str[(SCSI_MAX_CDBLEN * 3) + 1];
                struct cam_path *path;

                path = start_ccb->ccb_h.path;
#endif

                /*
                 * For the sake of compatibility with SCSI-1
                 * devices that may not understand the identify
                 * message, we include lun information in the
                 * second byte of all commands.  SCSI-1 specifies
                 * that luns are a 3 bit value and reserves only 3
                 * bits for lun information in the CDB.  Later
                 * revisions of the SCSI spec allow for more than 8
                 * luns, but have deprecated lun information in the
                 * CDB.  So, if the lun won't fit, we must omit.
                 *
                 * Also be aware that during initial probing for devices,
                 * the inquiry information is unknown but initialized to 0.
                 * This means that this code will be exercised while probing
                 * devices with an ANSI revision greater than 2.
                 */
                if (SID_ANSI_REV(&start_ccb->ccb_h.path->device->inq_data) <= 2
                 && start_ccb->ccb_h.target_lun < 8
                 && (start_ccb->ccb_h.flags & CAM_CDB_POINTER) == 0) {

                        start_ccb->csio.cdb_io.cdb_bytes[1] |=
                            start_ccb->ccb_h.target_lun << 5;
                }
                start_ccb->csio.scsi_status = SCSI_STATUS_OK;
                CAM_DEBUG(path, CAM_DEBUG_CDB,("%s. CDB: %s\n",
                          scsi_op_desc(start_ccb->csio.cdb_io.cdb_bytes[0],
                                       &path->device->inq_data),
                          scsi_cdb_string(start_ccb->csio.cdb_io.cdb_bytes,
                                          cdb_str, sizeof(cdb_str))));
                /* FALLTHROUGH */
        }
        case XPT_TARGET_IO:
        case XPT_CONT_TARGET_IO:
                start_ccb->csio.sense_resid = 0;
                start_ccb->csio.resid = 0;
                /* FALLTHROUGH */
        case XPT_RESET_DEV:
        case XPT_ENG_EXEC:
        {
                struct cam_path *path;
                int s;
                int runq;

                path = start_ccb->ccb_h.path;
                s = splsoftcam();

                cam_ccbq_insert_ccb(&path->device->ccbq, start_ccb);
                if (path->device->qfrozen_cnt == 0)
                        runq = xpt_schedule_dev_sendq(path->bus, path->device);
                else
                        runq = 0;
                splx(s);
                if (runq != 0)
                        xpt_run_dev_sendq(path->bus);
                break;
        }
        case XPT_SET_TRAN_SETTINGS:
        {
                xpt_set_transfer_settings(&start_ccb->cts,
                                          start_ccb->ccb_h.path->device,
                                          /*async_update*/FALSE);
                break;
        }
        case XPT_CALC_GEOMETRY:
        {
                struct cam_sim *sim;

                /* Filter out garbage */
                if (start_ccb->ccg.block_size == 0
                 || start_ccb->ccg.volume_size == 0) {
                        start_ccb->ccg.cylinders = 0;
                        start_ccb->ccg.heads = 0;
                        start_ccb->ccg.secs_per_track = 0;
                        start_ccb->ccb_h.status = CAM_REQ_CMP;
                        break;
                }
#ifdef PC98
                /*
                 * In a PC-98 system, geometry translation depens on
                 * the "real" device geometry obtained from mode page 4.
                 * SCSI geometry translation is performed in the
                 * initialization routine of the SCSI BIOS and the result
                 * stored in host memory.  If the translation is available
                 * in host memory, use it.  If not, rely on the default
                 * translation the device driver performs.
                 */
                if (scsi_da_bios_params(&start_ccb->ccg) != 0) {
                        start_ccb->ccb_h.status = CAM_REQ_CMP;
                        break;
                }
#endif
                sim = start_ccb->ccb_h.path->bus->sim;
                (*(sim->sim_action))(sim, start_ccb);
                break;
        }
        case XPT_ABORT:
        {
                union ccb* abort_ccb;
                int s;                          

                abort_ccb = start_ccb->cab.abort_ccb;
                if (XPT_FC_IS_DEV_QUEUED(abort_ccb)) {

                        if (abort_ccb->ccb_h.pinfo.index >= 0) {
                                struct cam_ccbq *ccbq;

                                ccbq = &abort_ccb->ccb_h.path->device->ccbq;
                                cam_ccbq_remove_ccb(ccbq, abort_ccb);
                                abort_ccb->ccb_h.status =
                                    CAM_REQ_ABORTED|CAM_DEV_QFRZN;
                                xpt_freeze_devq(abort_ccb->ccb_h.path, 1);
                                s = splcam();
                                xpt_done(abort_ccb);
                                splx(s);
                                start_ccb->ccb_h.status = CAM_REQ_CMP;
                                break;
                        }
                        if (abort_ccb->ccb_h.pinfo.index == CAM_UNQUEUED_INDEX
                         && (abort_ccb->ccb_h.status & CAM_SIM_QUEUED) == 0) {
                                /*
                                 * We've caught this ccb en route to
                                 * the SIM.  Flag it for abort and the
                                 * SIM will do so just before starting
                                 * real work on the CCB.
                                 */
                                abort_ccb->ccb_h.status =
                                    CAM_REQ_ABORTED|CAM_DEV_QFRZN;
                                xpt_freeze_devq(abort_ccb->ccb_h.path, 1);
                                start_ccb->ccb_h.status = CAM_REQ_CMP;
                                break;
                        }
                } 
                if (XPT_FC_IS_QUEUED(abort_ccb)
                 && (abort_ccb->ccb_h.pinfo.index == CAM_DONEQ_INDEX)) {
                        /*
                         * It's already completed but waiting
                         * for our SWI to get to it.
                         */
                        start_ccb->ccb_h.status = CAM_UA_ABORT;
                        break;
                }
                /*
                 * If we weren't able to take care of the abort request
                 * in the XPT, pass the request down to the SIM for processing.
                 */
                /* FALLTHROUGH */
        }
        case XPT_ACCEPT_TARGET_IO:
        case XPT_EN_LUN:
        case XPT_IMMED_NOTIFY:
        case XPT_NOTIFY_ACK:
        case XPT_GET_TRAN_SETTINGS:
        case XPT_RESET_BUS:
        {
                struct cam_sim *sim;

                sim = start_ccb->ccb_h.path->bus->sim;
                (*(sim->sim_action))(sim, start_ccb);
                break;
        }
        case XPT_PATH_INQ:
        {
                struct cam_sim *sim;

                sim = start_ccb->ccb_h.path->bus->sim;
                (*(sim->sim_action))(sim, start_ccb);
                break;
        }
        case XPT_PATH_STATS:
                start_ccb->cpis.last_reset =
                        start_ccb->ccb_h.path->bus->last_reset;
                start_ccb->ccb_h.status = CAM_REQ_CMP;
                break;
        case XPT_GDEV_TYPE:
        {
                struct cam_ed *dev;
                int s;

                dev = start_ccb->ccb_h.path->device;
                s = splcam();
                if ((dev->flags & CAM_DEV_UNCONFIGURED) != 0) {
                        start_ccb->ccb_h.status = CAM_DEV_NOT_THERE;
                } else {
                        struct ccb_getdev *cgd;
                        struct cam_eb *bus;
                        struct cam_et *tar;

                        cgd = &start_ccb->cgd;
                        bus = cgd->ccb_h.path->bus;
                        tar = cgd->ccb_h.path->target;
                        cgd->inq_data = dev->inq_data;
                        cgd->ccb_h.status = CAM_REQ_CMP;
                        cgd->serial_num_len = dev->serial_num_len;
                        if ((dev->serial_num_len > 0)
                         && (dev->serial_num != NULL))
                                bcopy(dev->serial_num, cgd->serial_num,
                                      dev->serial_num_len);
                }
                splx(s);
                break; 
        }
        case XPT_GDEV_STATS:
        {
                struct cam_ed *dev;
                int s;

                dev = start_ccb->ccb_h.path->device;
                s = splcam();
                if ((dev->flags & CAM_DEV_UNCONFIGURED) != 0) {
                        start_ccb->ccb_h.status = CAM_DEV_NOT_THERE;
                } else {
                        struct ccb_getdevstats *cgds;
                        struct cam_eb *bus;
                        struct cam_et *tar;

                        cgds = &start_ccb->cgds;
                        bus = cgds->ccb_h.path->bus;
                        tar = cgds->ccb_h.path->target;
                        cgds->dev_openings = dev->ccbq.dev_openings;
                        cgds->dev_active = dev->ccbq.dev_active;
                        cgds->devq_openings = dev->ccbq.devq_openings;
                        cgds->devq_queued = dev->ccbq.queue.entries;
                        cgds->held = dev->ccbq.held;
                        cgds->last_reset = tar->last_reset;
                        cgds->maxtags = dev->quirk->maxtags;
                        cgds->mintags = dev->quirk->mintags;
                        if (timevalcmp(&tar->last_reset, &bus->last_reset, <))
                                cgds->last_reset = bus->last_reset;
                        cgds->ccb_h.status = CAM_REQ_CMP;
                }
                splx(s);
                break;
        }
        case XPT_GDEVLIST:
        {
                struct cam_periph       *nperiph;
                struct periph_list      *periph_head;
                struct ccb_getdevlist   *cgdl;
                int                     i;
                int                     s;
                struct cam_ed           *device;
                int                     found;


                found = 0;

                /*
                 * Don't want anyone mucking with our data.
                 */
                s = splcam();
                device = start_ccb->ccb_h.path->device;
                periph_head = &device->periphs;
                cgdl = &start_ccb->cgdl;

                /*
                 * Check and see if the list has changed since the user
                 * last requested a list member.  If so, tell them that the
                 * list has changed, and therefore they need to start over 
                 * from the beginning.
                 */
                if ((cgdl->index != 0) && 
                    (cgdl->generation != device->generation)) {
                        cgdl->status = CAM_GDEVLIST_LIST_CHANGED;
                        splx(s);
                        break;
                }

                /*
                 * Traverse the list of peripherals and attempt to find 
                 * the requested peripheral.
                 */
                for (nperiph = SLIST_FIRST(periph_head), i = 0;
                     (nperiph != NULL) && (i <= cgdl->index);
                     nperiph = SLIST_NEXT(nperiph, periph_links), i++) {
                        if (i == cgdl->index) {
                                strncpy(cgdl->periph_name,
                                        nperiph->periph_name,
                                        DEV_IDLEN);
                                cgdl->unit_number = nperiph->unit_number;
                                found = 1;
                        }
                }
                if (found == 0) {
                        cgdl->status = CAM_GDEVLIST_ERROR;
                        splx(s);
                        break;
                }

                if (nperiph == NULL)
                        cgdl->status = CAM_GDEVLIST_LAST_DEVICE;
                else
                        cgdl->status = CAM_GDEVLIST_MORE_DEVS;

                cgdl->index++;
                cgdl->generation = device->generation;

                splx(s);
                cgdl->ccb_h.status = CAM_REQ_CMP;
                break;
        }
        case XPT_DEV_MATCH:
        {
                int s;
                dev_pos_type position_type;
                struct ccb_dev_match *cdm;
                int ret;

                cdm = &start_ccb->cdm;

                /*
                 * Prevent EDT changes while we traverse it.
                 */
                s = splcam();
                /*
                 * There are two ways of getting at information in the EDT.
                 * The first way is via the primary EDT tree.  It starts
                 * with a list of busses, then a list of targets on a bus,
                 * then devices/luns on a target, and then peripherals on a
                 * device/lun.  The "other" way is by the peripheral driver
                 * lists.  The peripheral driver lists are organized by
                 * peripheral driver.  (obviously)  So it makes sense to
                 * use the peripheral driver list if the user is looking
                 * for something like "da1", or all "da" devices.  If the
                 * user is looking for something on a particular bus/target
                 * or lun, it's generally better to go through the EDT tree.
                 */

                if (cdm->pos.position_type != CAM_DEV_POS_NONE)
                        position_type = cdm->pos.position_type;
                else {
                        int i;

                        position_type = CAM_DEV_POS_NONE;

                        for (i = 0; i < cdm->num_patterns; i++) {
                                if ((cdm->patterns[i].type == DEV_MATCH_BUS)
                                 ||(cdm->patterns[i].type == DEV_MATCH_DEVICE)){
                                        position_type = CAM_DEV_POS_EDT;
                                        break;
                                }
                        }

                        if (cdm->num_patterns == 0)
                                position_type = CAM_DEV_POS_EDT;
                        else if (position_type == CAM_DEV_POS_NONE)
                                position_type = CAM_DEV_POS_PDRV;
                }

                switch(position_type & CAM_DEV_POS_TYPEMASK) {
                case CAM_DEV_POS_EDT:
                        ret = xptedtmatch(cdm);
                        break;
                case CAM_DEV_POS_PDRV:
                        ret = xptperiphlistmatch(cdm);
                        break;
                default:
                        cdm->status = CAM_DEV_MATCH_ERROR;
                        break;
                }

                splx(s);

                if (cdm->status == CAM_DEV_MATCH_ERROR)
                        start_ccb->ccb_h.status = CAM_REQ_CMP_ERR;
                else
                        start_ccb->ccb_h.status = CAM_REQ_CMP;

                break;
        }
        case XPT_SASYNC_CB:
        {
                struct ccb_setasync *csa;
                struct async_node *cur_entry;
                struct async_list *async_head;
                u_int32_t added;
                int s;

                csa = &start_ccb->csa;
                added = csa->event_enable;
                async_head = &csa->ccb_h.path->device->asyncs;

                /*
                 * If there is already an entry for us, simply
                 * update it.
                 */
                s = splcam();
                cur_entry = SLIST_FIRST(async_head);
                while (cur_entry != NULL) {
                        if ((cur_entry->callback_arg == csa->callback_arg)
                         && (cur_entry->callback == csa->callback))
                                break;
                        cur_entry = SLIST_NEXT(cur_entry, links);
                }

                if (cur_entry != NULL) {
                        /*
                         * If the request has no flags set,
                         * remove the entry.
                         */
                        added &= ~cur_entry->event_enable;
                        if (csa->event_enable == 0) {
                                SLIST_REMOVE(async_head, cur_entry,
                                             async_node, links);
                                csa->ccb_h.path->device->refcount--;
                                free(cur_entry, M_DEVBUF);
                        } else {
                                cur_entry->event_enable = csa->event_enable;
                        }
                } else {
                        cur_entry = malloc(sizeof(*cur_entry), M_DEVBUF,
                                           M_NOWAIT);
                        if (cur_entry == NULL) {
                                splx(s);
                                csa->ccb_h.status = CAM_RESRC_UNAVAIL;
                                break;
                        }
                        cur_entry->event_enable = csa->event_enable;
                        cur_entry->callback_arg = csa->callback_arg;
                        cur_entry->callback = csa->callback;
                        SLIST_INSERT_HEAD(async_head, cur_entry, links);
                        csa->ccb_h.path->device->refcount++;
                }

                if ((added & AC_FOUND_DEVICE) != 0) {
                        /*
                         * Get this peripheral up to date with all
                         * the currently existing devices.
                         */
                        xpt_for_all_devices(xptsetasyncfunc, cur_entry);
                }
                if ((added & AC_PATH_REGISTERED) != 0) {
                        /*
                         * Get this peripheral up to date with all
                         * the currently existing busses.
                         */
                        xpt_for_all_busses(xptsetasyncbusfunc, cur_entry);
                }
                splx(s);
                start_ccb->ccb_h.status = CAM_REQ_CMP;
                break;
        }
        case XPT_REL_SIMQ:
        {
                struct ccb_relsim *crs;
                struct cam_ed *dev;
                int s;

                crs = &start_ccb->crs;
                dev = crs->ccb_h.path->device;
                if (dev == NULL) {

                        crs->ccb_h.status = CAM_DEV_NOT_THERE;
                        break;
                }

                s = splcam();

                if ((crs->release_flags & RELSIM_ADJUST_OPENINGS) != 0) {

                        if ((dev->inq_data.flags & SID_CmdQue) != 0) {

                                /* Don't ever go below one opening */
                                if (crs->openings > 0) {
                                        xpt_dev_ccbq_resize(crs->ccb_h.path,
                                                            crs->openings);

                                        if (bootverbose) {
                                                xpt_print_path(crs->ccb_h.path);
                                                printf("tagged openings "
                                                       "now %d\n",
                                                       crs->openings);
                                        }
                                }
                        }
                }

                if ((crs->release_flags & RELSIM_RELEASE_AFTER_TIMEOUT) != 0) {

                        if ((dev->flags & CAM_DEV_REL_TIMEOUT_PENDING) != 0) {

                                /*
                                 * Just extend the old timeout and decrement
                                 * the freeze count so that a single timeout
                                 * is sufficient for releasing the queue.
                                 */
                                start_ccb->ccb_h.flags &= ~CAM_DEV_QFREEZE;
                                untimeout(xpt_release_devq_timeout,
                                          dev, dev->c_handle);
                        } else {

                                start_ccb->ccb_h.flags |= CAM_DEV_QFREEZE;
                        }

                        dev->c_handle =
                                timeout(xpt_release_devq_timeout,
                                        dev,
                                        (crs->release_timeout * hz) / 1000);

                        dev->flags |= CAM_DEV_REL_TIMEOUT_PENDING;

                }

                if ((crs->release_flags & RELSIM_RELEASE_AFTER_CMDCMPLT) != 0) {

                        if ((dev->flags & CAM_DEV_REL_ON_COMPLETE) != 0) {
                                /*
                                 * Decrement the freeze count so that a single
                                 * completion is still sufficient to unfreeze
                                 * the queue.
                                 */
                                start_ccb->ccb_h.flags &= ~CAM_DEV_QFREEZE;
                        } else {
                                
                                dev->flags |= CAM_DEV_REL_ON_COMPLETE;
                                start_ccb->ccb_h.flags |= CAM_DEV_QFREEZE;
                        }
                }

                if ((crs->release_flags & RELSIM_RELEASE_AFTER_QEMPTY) != 0) {

                        if ((dev->flags & CAM_DEV_REL_ON_QUEUE_EMPTY) != 0
                         || (dev->ccbq.dev_active == 0)) {

                                start_ccb->ccb_h.flags &= ~CAM_DEV_QFREEZE;
                        } else {
                                
                                dev->flags |= CAM_DEV_REL_ON_QUEUE_EMPTY;
                                start_ccb->ccb_h.flags |= CAM_DEV_QFREEZE;
                        }
                }
                splx(s);
                
                if ((start_ccb->ccb_h.flags & CAM_DEV_QFREEZE) == 0) {

                        xpt_release_devq(crs->ccb_h.path, /*count*/1,
                                         /*run_queue*/TRUE);
                }
                start_ccb->crs.qfrozen_cnt = dev->qfrozen_cnt;
                start_ccb->ccb_h.status = CAM_REQ_CMP;
                break;
        }
        case XPT_SCAN_BUS:
                xpt_scan_bus(start_ccb->ccb_h.path->periph, start_ccb);
                break;
        case XPT_SCAN_LUN:
                xpt_scan_lun(start_ccb->ccb_h.path->periph,
                             start_ccb->ccb_h.path, start_ccb->crcn.flags,
                             start_ccb);
                break;
        case XPT_DEBUG: {
#ifdef CAMDEBUG
                int s;
                
                s = splcam();
#ifdef CAM_DEBUG_DELAY
                cam_debug_delay = CAM_DEBUG_DELAY;
#endif
                cam_dflags = start_ccb->cdbg.flags;
                if (cam_dpath != NULL) {
                        xpt_free_path(cam_dpath);
                        cam_dpath = NULL;
                }

                if (cam_dflags != CAM_DEBUG_NONE) {
                        if (xpt_create_path(&cam_dpath, xpt_periph,
                                            start_ccb->ccb_h.path_id,
                                            start_ccb->ccb_h.target_id,
                                            start_ccb->ccb_h.target_lun) !=
                                            CAM_REQ_CMP) {
                                start_ccb->ccb_h.status = CAM_RESRC_UNAVAIL;
                                cam_dflags = CAM_DEBUG_NONE;
                        } else {
                                start_ccb->ccb_h.status = CAM_REQ_CMP;
                                xpt_print_path(cam_dpath);
                                printf("debugging flags now %x\n", cam_dflags);
                        }
                } else {
                        cam_dpath = NULL;
                        start_ccb->ccb_h.status = CAM_REQ_CMP;
                }
                splx(s);
#else /* !CAMDEBUG */
                start_ccb->ccb_h.status = CAM_FUNC_NOTAVAIL;
#endif /* CAMDEBUG */
                break;
        }
        case XPT_NOOP:
                if ((start_ccb->ccb_h.flags & CAM_DEV_QFREEZE) != 0)
                        xpt_freeze_devq(start_ccb->ccb_h.path, 1);
                start_ccb->ccb_h.status = CAM_REQ_CMP;
                break;
        default:
        case XPT_SDEV_TYPE:
        case XPT_TERM_IO:
        case XPT_ENG_INQ:
                /* XXX Implement */
                start_ccb->ccb_h.status = CAM_PROVIDE_FAIL;
                break;
        }
        splx(iopl);
}

void
xpt_polled_action(union ccb *start_ccb)
{
        int       s;
        u_int32_t timeout;
        struct    cam_sim *sim; 
        struct    cam_devq *devq;
        struct    cam_ed *dev;

        timeout = start_ccb->ccb_h.timeout;
        sim = start_ccb->ccb_h.path->bus->sim;
        devq = sim->devq;
        dev = start_ccb->ccb_h.path->device;

        s = splcam();

        /*
         * Steal an opening so that no other queued requests
         * can get it before us while we simulate interrupts.
         */
        dev->ccbq.devq_openings--;
        dev->ccbq.dev_openings--;       
        
        while((devq->send_openings <= 0 || dev->ccbq.dev_openings < 0)
           && (--timeout > 0)) {
                DELAY(1000);
                (*(sim->sim_poll))(sim);
                camisr(&cam_netq);
                camisr(&cam_bioq);
        }
        
        dev->ccbq.devq_openings++;
        dev->ccbq.dev_openings++;
        
        if (timeout != 0) {
                xpt_action(start_ccb);
                while(--timeout > 0) {
                        (*(sim->sim_poll))(sim);
                        camisr(&cam_netq);
                        camisr(&cam_bioq);
                        if ((start_ccb->ccb_h.status  & CAM_STATUS_MASK)
                            != CAM_REQ_INPROG)
                                break;
                        DELAY(1000);
                }
                if (timeout == 0) {
                        /*
                         * XXX Is it worth adding a sim_timeout entry
                         * point so we can attempt recovery?  If
                         * this is only used for dumps, I don't think
                         * it is.
                         */
                        start_ccb->ccb_h.status = CAM_CMD_TIMEOUT;
                }
        } else {
                start_ccb->ccb_h.status = CAM_RESRC_UNAVAIL;
        }
        splx(s);
}
        
/*
 * Schedule a peripheral driver to receive a ccb when it's
 * target device has space for more transactions.
 */
void
xpt_schedule(struct cam_periph *perph, u_int32_t new_priority)
{
        struct cam_ed *device;
        int s;
        int runq;

        CAM_DEBUG(perph->path, CAM_DEBUG_TRACE, ("xpt_schedule\n"));
        device = perph->path->device;
        s = splsoftcam();
        if (periph_is_queued(perph)) {
                /* Simply reorder based on new priority */
                CAM_DEBUG(perph->path, CAM_DEBUG_SUBTRACE,
                          ("   change priority to %d\n", new_priority));
                if (new_priority < perph->pinfo.priority) {
                        camq_change_priority(&device->drvq,
                                             perph->pinfo.index,
                                             new_priority);
                }
                runq = 0;
        } else {
                /* New entry on the queue */
                CAM_DEBUG(perph->path, CAM_DEBUG_SUBTRACE,
                          ("   added periph to queue\n"));
                perph->pinfo.priority = new_priority;
                perph->pinfo.generation = ++device->drvq.generation;
                camq_insert(&device->drvq, &perph->pinfo);
                runq = xpt_schedule_dev_allocq(perph->path->bus, device);
        }
        splx(s);
        if (runq != 0) {
                CAM_DEBUG(perph->path, CAM_DEBUG_SUBTRACE,
                          ("   calling xpt_run_devq\n"));
                xpt_run_dev_allocq(perph->path->bus);
        }
}


/*
 * Schedule a device to run on a given queue.
 * If the device was inserted as a new entry on the queue,
 * return 1 meaning the device queue should be run. If we
 * were already queued, implying someone else has already
 * started the queue, return 0 so the caller doesn't attempt
 * to run the queue.  Must be run at either splsoftcam
 * (or splcam since that encompases splsoftcam).
 */
static int
xpt_schedule_dev(struct camq *queue, cam_pinfo *pinfo,
                 u_int32_t new_priority)
{
        int retval;
        u_int32_t old_priority;

        CAM_DEBUG_PRINT(CAM_DEBUG_XPT, ("xpt_schedule_dev\n"));

        old_priority = pinfo->priority;

        /*
         * Are we already queued?
         */
        if (pinfo->index != CAM_UNQUEUED_INDEX) {
                /* Simply reorder based on new priority */
                if (new_priority < old_priority) {
                        camq_change_priority(queue, pinfo->index,
                                             new_priority);
                        CAM_DEBUG_PRINT(CAM_DEBUG_XPT,
                                        ("changed priority to %d\n",
                                         new_priority));
                }
                retval = 0;
        } else {
                /* New entry on the queue */
                if (new_priority < old_priority)
                        pinfo->priority = new_priority;

                CAM_DEBUG_PRINT(CAM_DEBUG_XPT,
                                ("Inserting onto queue\n"));
                pinfo->generation = ++queue->generation;
                camq_insert(queue, pinfo);
                retval = 1;
        }
        return (retval);
}

static void
xpt_run_dev_allocq(struct cam_eb *bus)
{
        struct  cam_devq *devq;
        int     s;

        CAM_DEBUG_PRINT(CAM_DEBUG_XPT, ("xpt_run_dev_allocq\n"));
        devq = bus->sim->devq;

        CAM_DEBUG_PRINT(CAM_DEBUG_XPT,
                        ("   qfrozen_cnt == 0x%x, entries == %d, "
                         "openings == %d, active == %d\n",
                         devq->alloc_queue.qfrozen_cnt,
                         devq->alloc_queue.entries,
                         devq->alloc_openings,
                         devq->alloc_active));

        s = splsoftcam();
        devq->alloc_queue.qfrozen_cnt++;
        while ((devq->alloc_queue.entries > 0)
            && (devq->alloc_openings > 0)
            && (devq->alloc_queue.qfrozen_cnt <= 1)) {
                struct  cam_ed_qinfo *qinfo;
                struct  cam_ed *device;
                union   ccb *work_ccb;
                struct  cam_periph *drv;
                struct  camq *drvq;
                
                qinfo = (struct cam_ed_qinfo *)camq_remove(&devq->alloc_queue,
                                                           CAMQ_HEAD);
                device = qinfo->device;

                CAM_DEBUG_PRINT(CAM_DEBUG_XPT,
                                ("running device %p\n", device));

                drvq = &device->drvq;

#ifdef CAMDEBUG
                if (drvq->entries <= 0) {
                        panic("xpt_run_dev_allocq: "
                              "Device on queue without any work to do");
                }
#endif
                if ((work_ccb = xpt_get_ccb(device)) != NULL) {
                        devq->alloc_openings--;
                        devq->alloc_active++;
                        drv = (struct cam_periph*)camq_remove(drvq, CAMQ_HEAD);
                        splx(s);
                        xpt_setup_ccb(&work_ccb->ccb_h, drv->path,
                                      drv->pinfo.priority);
                        CAM_DEBUG_PRINT(CAM_DEBUG_XPT,
                                        ("calling periph start\n"));
                        drv->periph_start(drv, work_ccb);
                } else {
                        /*
                         * Malloc failure in alloc_ccb
                         */
                        /*
                         * XXX add us to a list to be run from free_ccb
                         * if we don't have any ccbs active on this
                         * device queue otherwise we may never get run
                         * again.
                         */
                        break;
                }
        
                /* Raise IPL for possible insertion and test at top of loop */
                s = splsoftcam();

                if (drvq->entries > 0) {
                        /* We have more work.  Attempt to reschedule */
                        xpt_schedule_dev_allocq(bus, device);
                }
        }
        devq->alloc_queue.qfrozen_cnt--;
        splx(s);
}

static void
xpt_run_dev_sendq(struct cam_eb *bus)
{
        struct  cam_devq *devq;
        int     s;

        CAM_DEBUG_PRINT(CAM_DEBUG_XPT, ("xpt_run_dev_sendq\n"));
        
        devq = bus->sim->devq;

        s = splcam();
        devq->send_queue.qfrozen_cnt++;
        splx(s);
        s = splsoftcam();
        while ((devq->send_queue.entries > 0)
            && (devq->send_openings > 0)) {
                struct  cam_ed_qinfo *qinfo;
                struct  cam_ed *device;
                union ccb *work_ccb;
                struct  cam_sim *sim;
                int     ospl;

                ospl = splcam();
                if (devq->send_queue.qfrozen_cnt > 1) {
                        splx(ospl);
                        break;
                }

                qinfo = (struct cam_ed_qinfo *)camq_remove(&devq->send_queue,
                                                           CAMQ_HEAD);
                device = qinfo->device;

                /*
                 * If the device has been "frozen", don't attempt
                 * to run it.
                 */
                if (device->qfrozen_cnt > 0) {
                        splx(ospl);
                        continue;
                }

                CAM_DEBUG_PRINT(CAM_DEBUG_XPT,
                                ("running device %p\n", device));

                work_ccb = cam_ccbq_peek_ccb(&device->ccbq, CAMQ_HEAD);
                if (work_ccb == NULL) {
                        printf("device on run queue with no ccbs???");
                        splx(ospl);
                        continue;
                }

                if ((work_ccb->ccb_h.flags & CAM_HIGH_POWER) != 0) {

                        if (num_highpower <= 0) {
                                /*
                                 * We got a high power command, but we
                                 * don't have any available slots.  Freeze
                                 * the device queue until we have a slot
                                 * available.
                                 */
                                device->qfrozen_cnt++;
                                STAILQ_INSERT_TAIL(&highpowerq, 
                                                   &work_ccb->ccb_h, 
                                                   xpt_links.stqe);

                                splx(ospl);
                                continue;
                        } else {
                                /*
                                 * Consume a high power slot while
                                 * this ccb runs.
                                 */
                                num_highpower--;
                        }
                }
                devq->active_dev = device;
                cam_ccbq_remove_ccb(&device->ccbq, work_ccb);

                cam_ccbq_send_ccb(&device->ccbq, work_ccb);
                splx(ospl);

                devq->send_openings--;
                devq->send_active++;            
                
                if (device->ccbq.queue.entries > 0)
                        xpt_schedule_dev_sendq(bus, device);

                if (work_ccb && (work_ccb->ccb_h.flags & CAM_DEV_QFREEZE) != 0){
                        /*
                         * The client wants to freeze the queue
                         * after this CCB is sent.
                         */
                        ospl = splcam();
                        device->qfrozen_cnt++;
                        splx(ospl);
                }
                
                splx(s);

                /* In Target mode, the peripheral driver knows best... */
                if (work_ccb->ccb_h.func_code == XPT_SCSI_IO) {
                        if ((device->inq_flags & SID_CmdQue) != 0
                         && work_ccb->csio.tag_action != CAM_TAG_ACTION_NONE)
                                work_ccb->ccb_h.flags |= CAM_TAG_ACTION_VALID;
                        else
                                /*
                                 * Clear this in case of a retried CCB that
                                 * failed due to a rejected tag.
                                 */
                                work_ccb->ccb_h.flags &= ~CAM_TAG_ACTION_VALID;
                }

                /*
                 * Device queues can be shared among multiple sim instances
                 * that reside on different busses.  Use the SIM in the queue
                 * CCB's path, rather than the one in the bus that was passed
                 * into this function.
                 */
                sim = work_ccb->ccb_h.path->bus->sim;
                (*(sim->sim_action))(sim, work_ccb);

                ospl = splcam();
                devq->active_dev = NULL;
                splx(ospl);
                /* Raise IPL for possible insertion and test at top of loop */
                s = splsoftcam();
        }
        splx(s);
        s = splcam();
        devq->send_queue.qfrozen_cnt--;
        splx(s);
}

/*
 * This function merges stuff from the slave ccb into the master ccb, while
 * keeping important fields in the master ccb constant.
 */
void
xpt_merge_ccb(union ccb *master_ccb, union ccb *slave_ccb)
{
        /*
         * Pull fields that are valid for peripheral drivers to set
         * into the master CCB along with the CCB "payload".
         */
        master_ccb->ccb_h.retry_count = slave_ccb->ccb_h.retry_count;
        master_ccb->ccb_h.func_code = slave_ccb->ccb_h.func_code;
        master_ccb->ccb_h.timeout = slave_ccb->ccb_h.timeout;
        master_ccb->ccb_h.flags = slave_ccb->ccb_h.flags;
        bcopy(&(&slave_ccb->ccb_h)[1], &(&master_ccb->ccb_h)[1],
              sizeof(union ccb) - sizeof(struct ccb_hdr));
}

void
xpt_setup_ccb(struct ccb_hdr *ccb_h, struct cam_path *path, u_int32_t priority)
{
        CAM_DEBUG(path, CAM_DEBUG_TRACE, ("xpt_setup_ccb\n"));
        ccb_h->pinfo.priority = priority;
        ccb_h->path = path;
        ccb_h->path_id = path->bus->path_id;
        if (path->target)
                ccb_h->target_id = path->target->target_id;
        else
                ccb_h->target_id = CAM_TARGET_WILDCARD;
        if (path->device) {
                ccb_h->target_lun = path->device->lun_id;
                ccb_h->pinfo.generation = ++path->device->ccbq.queue.generation;
        } else {
                ccb_h->target_lun = CAM_TARGET_WILDCARD;
        }
        ccb_h->pinfo.index = CAM_UNQUEUED_INDEX;
        ccb_h->flags = 0;
}

/* Path manipulation functions */
cam_status
xpt_create_path(struct cam_path **new_path_ptr, struct cam_periph *perph,
                path_id_t path_id, target_id_t target_id, lun_id_t lun_id)
{
        struct     cam_path *path;
        cam_status status;

        path = (struct cam_path *)malloc(sizeof(*path), M_DEVBUF, M_NOWAIT);

        if (path == NULL) {
                status = CAM_RESRC_UNAVAIL;
                return(status);
        }
        status = xpt_compile_path(path, perph, path_id, target_id, lun_id);
        if (status != CAM_REQ_CMP) {
                free(path, M_DEVBUF);
                path = NULL;
        }
        *new_path_ptr = path;
        return (status);
}

static cam_status
xpt_compile_path(struct cam_path *new_path, struct cam_periph *perph,
                 path_id_t path_id, target_id_t target_id, lun_id_t lun_id)
{
        struct       cam_eb *bus;
        struct       cam_et *target;
        struct       cam_ed *device;
        cam_status   status;
        int          s;

        status = CAM_REQ_CMP;   /* Completed without error */
        target = NULL;          /* Wildcarded */
        device = NULL;          /* Wildcarded */

        /*
         * We will potentially modify the EDT, so block interrupts
         * that may attempt to create cam paths.
         */
        s = splcam();
        bus = xpt_find_bus(path_id);
        if (bus == NULL) {
                status = CAM_PATH_INVALID;
        } else {
                target = xpt_find_target(bus, target_id);
                if (target == NULL) {
                        /* Create one */
                        struct cam_et *new_target;

                        new_target = xpt_alloc_target(bus, target_id);
                        if (new_target == NULL) {
                                status = CAM_RESRC_UNAVAIL;
                        } else {
                                target = new_target;
                        }
                }
                if (target != NULL) {
                        device = xpt_find_device(target, lun_id);
                        if (device == NULL) {
                                /* Create one */
                                struct cam_ed *new_device;

                                new_device = xpt_alloc_device(bus,
                                                              target,
                                                              lun_id);
                                if (new_device == NULL) {
                                        status = CAM_RESRC_UNAVAIL;
                                } else {
                                        device = new_device;
                                }
                        }
                }
        }
        splx(s);

        /*
         * Only touch the user's data if we are successful.
         */
        if (status == CAM_REQ_CMP) {
                new_path->periph = perph;
                new_path->bus = bus;
                new_path->target = target;
                new_path->device = device;
                CAM_DEBUG(new_path, CAM_DEBUG_TRACE, ("xpt_compile_path\n"));
        } else {
                if (device != NULL)
                        xpt_release_device(bus, target, device);
                if (target != NULL)
                        xpt_release_target(bus, target);
                if (bus != NULL)
                        xpt_release_bus(bus);
        }
        return (status);
}

static void
xpt_release_path(struct cam_path *path)
{
        CAM_DEBUG(path, CAM_DEBUG_TRACE, ("xpt_release_path\n"));
        if (path->device != NULL) {
                xpt_release_device(path->bus, path->target, path->device);
                path->device = NULL;
        }
        if (path->target != NULL) {
                xpt_release_target(path->bus, path->target);
                path->target = NULL;
        }
        if (path->bus != NULL) {
                xpt_release_bus(path->bus);
                path->bus = NULL;
        }
}

void
xpt_free_path(struct cam_path *path)
{
        CAM_DEBUG(path, CAM_DEBUG_TRACE, ("xpt_free_path\n"));
        xpt_release_path(path);
        free(path, M_DEVBUF);
}


/*
 * Return -1 for failure, 0 for exact match, 1 for match with wildcards
 * in path1, 2 for match with wildcards in path2.
 */
int
xpt_path_comp(struct cam_path *path1, struct cam_path *path2)
{
        int retval = 0;

        if (path1->bus != path2->bus) {
                if (path1->bus->path_id == CAM_BUS_WILDCARD)
                        retval = 1;
                else if (path2->bus->path_id == CAM_BUS_WILDCARD)
                        retval = 2;
                else
                        return (-1);
        }
        if (path1->target != path2->target) {
                if (path1->target->target_id == CAM_TARGET_WILDCARD) {
                        if (retval == 0)
                                retval = 1;
                } else if (path2->target->target_id == CAM_TARGET_WILDCARD)
                        retval = 2;
                else
                        return (-1);
        }
        if (path1->device != path2->device) {
                if (path1->device->lun_id == CAM_LUN_WILDCARD) {
                        if (retval == 0)
                                retval = 1;
                } else if (path2->device->lun_id == CAM_LUN_WILDCARD)
                        retval = 2;
                else
                        return (-1);
        }
        return (retval);
}

void
xpt_print_path(struct cam_path *path)
{
        if (path == NULL)
                printf("(nopath): ");
        else {
                if (path->periph != NULL)
                        printf("(%s%d:", path->periph->periph_name,
                               path->periph->unit_number);
                else
                        printf("(noperiph:");

                if (path->bus != NULL)
                        printf("%s%d:%d:", path->bus->sim->sim_name,
                               path->bus->sim->unit_number,
                               path->bus->sim->bus_id);
                else
                        printf("nobus:");

                if (path->target != NULL)
                        printf("%d:", path->target->target_id);
                else
                        printf("X:");

                if (path->device != NULL)
                        printf("%d): ", path->device->lun_id);
                else
                        printf("X): ");
        }
}

path_id_t
xpt_path_path_id(struct cam_path *path)
{
        return(path->bus->path_id);
}

target_id_t
xpt_path_target_id(struct cam_path *path)
{
        if (path->target != NULL)
                return (path->target->target_id);
        else
                return (CAM_TARGET_WILDCARD);
}

lun_id_t
xpt_path_lun_id(struct cam_path *path)
{
        if (path->device != NULL)
                return (path->device->lun_id);
        else
                return (CAM_LUN_WILDCARD);
}

struct cam_sim *
xpt_path_sim(struct cam_path *path)
{
        return (path->bus->sim);
}

struct cam_periph*
xpt_path_periph(struct cam_path *path)
{
        return (path->periph);
}

/*
 * Release a CAM control block for the caller.  Remit the cost of the structure
 * to the device referenced by the path.  If the this device had no 'credits'
 * and peripheral drivers have registered async callbacks for this notification
 * call them now.
 */
void
xpt_release_ccb(union ccb *free_ccb)
{
        int      s;
        struct   cam_path *path;
        struct   cam_ed *device;
        struct   cam_eb *bus;

        CAM_DEBUG_PRINT(CAM_DEBUG_XPT, ("xpt_release_ccb\n"));
        path = free_ccb->ccb_h.path;
        device = path->device;
        bus = path->bus;
        s = splsoftcam();
        cam_ccbq_release_opening(&device->ccbq);
        if (xpt_ccb_count > xpt_max_ccbs) {
                xpt_free_ccb(free_ccb);
                xpt_ccb_count--;
        } else {
                SLIST_INSERT_HEAD(&ccb_freeq, &free_ccb->ccb_h, xpt_links.sle);
        }
        bus->sim->devq->alloc_openings++;
        bus->sim->devq->alloc_active--;
        /* XXX Turn this into an inline function - xpt_run_device?? */
        if ((device_is_alloc_queued(device) == 0)
         && (device->drvq.entries > 0)) {
                xpt_schedule_dev_allocq(bus, device);
        }
        splx(s);
        if (dev_allocq_is_runnable(bus->sim->devq))
                xpt_run_dev_allocq(bus);
}

/* Functions accessed by SIM drivers */

/*
 * A sim structure, listing the SIM entry points and instance
 * identification info is passed to xpt_bus_register to hook the SIM
 * into the CAM framework.  xpt_bus_register creates a cam_eb entry
 * for this new bus and places it in the array of busses and assigns
 * it a path_id.  The path_id may be influenced by "hard wiring"
 * information specified by the user.  Once interrupt services are
 * availible, the bus will be probed.
 */
int32_t
xpt_bus_register(struct cam_sim *sim, u_int32_t bus)
{
        struct cam_eb *new_bus;
        struct cam_eb *old_bus;
        struct ccb_pathinq cpi;
        int s;

        sim->bus_id = bus;
        new_bus = (struct cam_eb *)malloc(sizeof(*new_bus),
                                          M_DEVBUF, M_NOWAIT);
        if (new_bus == NULL) {
                /* Couldn't satisfy request */
                return (CAM_RESRC_UNAVAIL);
        }

        if (strcmp(sim->sim_name, "xpt") != 0) {

                sim->path_id =
                    xptpathid(sim->sim_name, sim->unit_number, sim->bus_id);
        }

        TAILQ_INIT(&new_bus->et_entries);
        new_bus->path_id = sim->path_id;
        new_bus->sim = sim;
        timevalclear(&new_bus->last_reset);
        new_bus->flags = 0;
        new_bus->refcount = 1;  /* Held until a bus_deregister event */
        new_bus->generation = 0;
        s = splcam();
        old_bus = TAILQ_FIRST(&xpt_busses);
        while (old_bus != NULL
            && old_bus->path_id < new_bus->path_id)
                old_bus = TAILQ_NEXT(old_bus, links);
        if (old_bus != NULL)
                TAILQ_INSERT_BEFORE(old_bus, new_bus, links);
        else
                TAILQ_INSERT_TAIL(&xpt_busses, new_bus, links);
        bus_generation++;
        splx(s);

        /* Notify interested parties */
        if (sim->path_id != CAM_XPT_PATH_ID) {
                struct cam_path path;

                xpt_compile_path(&path, /*periph*/NULL, sim->path_id,
                                 CAM_TARGET_WILDCARD, CAM_LUN_WILDCARD);
                xpt_setup_ccb(&cpi.ccb_h, &path, /*priority*/1);
                cpi.ccb_h.func_code = XPT_PATH_INQ;
                xpt_action((union ccb *)&cpi);
                xpt_async(AC_PATH_REGISTERED, xpt_periph->path, &cpi);
                xpt_release_path(&path);
        }
        return (CAM_SUCCESS);
}

int32_t
xpt_bus_deregister(path_id_t pathid)
{
        struct cam_path bus_path;
        cam_status status;

        status = xpt_compile_path(&bus_path, NULL, pathid,
                                  CAM_TARGET_WILDCARD, CAM_LUN_WILDCARD);
        if (status != CAM_REQ_CMP)
                return (status);

        xpt_async(AC_LOST_DEVICE, &bus_path, NULL);
        xpt_async(AC_PATH_DEREGISTERED, &bus_path, NULL);
        
        /* Release the reference count held while registered. */
        xpt_release_bus(bus_path.bus);
        xpt_release_path(&bus_path);

        return (CAM_REQ_CMP);
}

static path_id_t
xptnextfreepathid(void)
{
        struct cam_eb *bus;
        path_id_t pathid;
        char *strval;

        pathid = 0;
        bus = TAILQ_FIRST(&xpt_busses);
retry:
        /* Find an unoccupied pathid */
        while (bus != NULL
            && bus->path_id <= pathid) {
                if (bus->path_id == pathid)
                        pathid++;
                bus = TAILQ_NEXT(bus, links);
        }

        /*
         * Ensure that this pathid is not reserved for
         * a bus that may be registered in the future.
         */
        if (resource_string_value("scbus", pathid, "at", &strval) == 0) {
                ++pathid;
                /* Start the search over */
                goto retry;
        }
        return (pathid);
}

static path_id_t
xptpathid(const char *sim_name, int sim_unit, int sim_bus)
{
        path_id_t pathid;
        int i, dunit, val;
        char buf[32];

        pathid = CAM_XPT_PATH_ID;
        snprintf(buf, sizeof(buf), "%s%d", sim_name, sim_unit);
        i = -1;
        while ((i = resource_query_string(i, "at", buf)) != -1) {
                if (strcmp(resource_query_name(i), "scbus")) {
                        /* Avoid a bit of foot shooting. */
                        continue;
                }
                dunit = resource_query_unit(i);
                if (dunit < 0)          /* unwired?! */
                        continue;
                if (resource_int_value("scbus", dunit, "bus", &val) == 0) {
                        if (sim_bus == val) {
                                pathid = dunit;
                                break;
                        }
                } else if (sim_bus == 0) {
                        /* Unspecified matches bus 0 */
                        pathid = dunit;
                        break;
                } else {
                        printf("Ambiguous scbus configuration for %s%d "
                               "bus %d, cannot wire down.  The kernel "
                               "config entry for scbus%d should "
                               "specify a controller bus.\n"
                               "Scbus will be assigned dynamically.\n",
                               sim_name, sim_unit, sim_bus, dunit);
                        break;
                }
        }

        if (pathid == CAM_XPT_PATH_ID)
                pathid = xptnextfreepathid();
        return (pathid);
}

void
xpt_async(u_int32_t async_code, struct cam_path *path, void *async_arg)
{
        struct cam_eb *bus;
        struct cam_et *target, *next_target;
        struct cam_ed *device, *next_device;
        int s;

        CAM_DEBUG(path, CAM_DEBUG_TRACE, ("xpt_async\n"));

        /*
         * Most async events come from a CAM interrupt context.  In
         * a few cases, the error recovery code at the peripheral layer,
         * which may run from our SWI or a process context, may signal
         * deferred events with a call to xpt_async. Ensure async
         * notifications are serialized by blocking cam interrupts.
         */
        s = splcam();

        bus = path->bus;

        if (async_code == AC_BUS_RESET) { 
                int s;

                s = splclock();
                /* Update our notion of when the last reset occurred */
                microtime(&bus->last_reset);
                splx(s);
        }

        for (target = TAILQ_FIRST(&bus->et_entries);
             target != NULL;
             target = next_target) {

                next_target = TAILQ_NEXT(target, links);

                if (path->target != target
                 && path->target->target_id != CAM_TARGET_WILDCARD
                 && target->target_id != CAM_TARGET_WILDCARD)
                        continue;

                if (async_code == AC_SENT_BDR) {
                        int s;

                        /* Update our notion of when the last reset occurred */
                        s = splclock();
                        microtime(&path->target->last_reset);
                        splx(s);
                }

                for (device = TAILQ_FIRST(&target->ed_entries);
                     device != NULL;
                     device = next_device) {

                        next_device = TAILQ_NEXT(device, links);

                        if (path->device != device 
                         && path->device->lun_id != CAM_LUN_WILDCARD
                         && device->lun_id != CAM_LUN_WILDCARD)
                                continue;

                        xpt_dev_async(async_code, bus, target,
                                      device, async_arg);

                        xpt_async_bcast(&device->asyncs, async_code,
                                        path, async_arg);
                }
        }
        
        /*
         * If this wasn't a fully wildcarded async, tell all
         * clients that want all async events.
         */
        if (bus != xpt_periph->path->bus)
                xpt_async_bcast(&xpt_periph->path->device->asyncs, async_code,
                                path, async_arg);
        splx(s);
}

static void
xpt_async_bcast(struct async_list *async_head,
                u_int32_t async_code,
                struct cam_path *path, void *async_arg)
{
        struct async_node *cur_entry;

        cur_entry = SLIST_FIRST(async_head);
        while (cur_entry != NULL) {
                struct async_node *next_entry;
                /*
                 * Grab the next list entry before we call the current
                 * entry's callback.  This is because the callback function
                 * can delete its async callback entry.
                 */
                next_entry = SLIST_NEXT(cur_entry, links);
                if ((cur_entry->event_enable & async_code) != 0)
                        cur_entry->callback(cur_entry->callback_arg,
                                            async_code, path,
                                            async_arg);
                cur_entry = next_entry;
        }
}

/*
 * Handle any per-device event notifications that require action by the XPT.
 */
static void
xpt_dev_async(u_int32_t async_code, struct cam_eb *bus, struct cam_et *target,
              struct cam_ed *device, void *async_arg)
{
        cam_status status;
        struct cam_path newpath;

        /*
         * We only need to handle events for real devices.
         */
        if (target->target_id == CAM_TARGET_WILDCARD
         || device->lun_id == CAM_LUN_WILDCARD)
                return;

        /*
         * We need our own path with wildcards expanded to
         * handle certain types of events.
         */
        if ((async_code == AC_SENT_BDR)
         || (async_code == AC_BUS_RESET)
         || (async_code == AC_INQ_CHANGED))
                status = xpt_compile_path(&newpath, NULL,
                                          bus->path_id,
                                          target->target_id,
                                          device->lun_id);
        else
                status = CAM_REQ_CMP_ERR;

        if (status == CAM_REQ_CMP) {

                /*
                 * Allow transfer negotiation to occur in a
                 * tag free environment.
                 */
                if (async_code == AC_SENT_BDR
                 || async_code == AC_BUS_RESET)
                        xpt_toggle_tags(&newpath);

                if (async_code == AC_INQ_CHANGED) {
                        /*
                         * We've sent a start unit command, or
                         * something similar to a device that
                         * may have caused its inquiry data to
                         * change. So we re-scan the device to
                         * refresh the inquiry data for it.
                         */
                        xpt_scan_lun(newpath.periph, &newpath,
                                     CAM_EXPECT_INQ_CHANGE, NULL);
                }
                xpt_release_path(&newpath);
        } else if (async_code == AC_LOST_DEVICE) {
                device->flags |= CAM_DEV_UNCONFIGURED;
        } else if (async_code == AC_TRANSFER_NEG) {
                struct ccb_trans_settings *settings;

                settings = (struct ccb_trans_settings *)async_arg;
                xpt_set_transfer_settings(settings, device,
                                          /*async_update*/TRUE);
        }
}

u_int32_t
xpt_freeze_devq(struct cam_path *path, u_int count)
{
        int s;
        struct ccb_hdr *ccbh;

        s = splcam();
        path->device->qfrozen_cnt += count;

        /*
         * Mark the last CCB in the queue as needing
         * to be requeued if the driver hasn't
         * changed it's state yet.  This fixes a race
         * where a ccb is just about to be queued to
         * a controller driver when it's interrupt routine
         * freezes the queue.  To completly close the
         * hole, controller drives must check to see
         * if a ccb's status is still CAM_REQ_INPROG
         * under spl protection just before they queue
         * the CCB.  See ahc_action/ahc_freeze_devq for
         * an example.
         */
        ccbh = TAILQ_LAST(&path->device->ccbq.active_ccbs, ccb_hdr_tailq);
        if (ccbh && ccbh->status == CAM_REQ_INPROG)
                ccbh->status = CAM_REQUEUE_REQ;
        splx(s);
        return (path->device->qfrozen_cnt);
}

u_int32_t
xpt_freeze_simq(struct cam_sim *sim, u_int count)
{
        sim->devq->send_queue.qfrozen_cnt += count;
        if (sim->devq->active_dev != NULL) {
                struct ccb_hdr *ccbh;
                
                ccbh = TAILQ_LAST(&sim->devq->active_dev->ccbq.active_ccbs,
                                  ccb_hdr_tailq);
                if (ccbh && ccbh->status == CAM_REQ_INPROG)
                        ccbh->status = CAM_REQUEUE_REQ;
        }
        return (sim->devq->send_queue.qfrozen_cnt);
}

static void
xpt_release_devq_timeout(void *arg)
{
        struct cam_ed *device;

        device = (struct cam_ed *)arg;

        xpt_release_devq_device(device, /*count*/1, /*run_queue*/TRUE);
}

void
xpt_release_devq(struct cam_path *path, u_int count, int run_queue)
{
        xpt_release_devq_device(path->device, count, run_queue);
}

static void
xpt_release_devq_device(struct cam_ed *dev, u_int count, int run_queue)
{
        int     rundevq;
        int     s0, s1;

        rundevq = 0;
        s0 = splsoftcam();
        s1 = splcam();
        if (dev->qfrozen_cnt > 0) {

                count = (count > dev->qfrozen_cnt) ? dev->qfrozen_cnt : count;
                dev->qfrozen_cnt -= count;
                if (dev->qfrozen_cnt == 0) {

                        /*
                         * No longer need to wait for a successful
                         * command completion.
                         */
                        dev->flags &= ~CAM_DEV_REL_ON_COMPLETE;

                        /*
                         * Remove any timeouts that might be scheduled
                         * to release this queue.
                         */
                        if ((dev->flags & CAM_DEV_REL_TIMEOUT_PENDING) != 0) {
                                untimeout(xpt_release_devq_timeout, dev,
                                          dev->c_handle);
                                dev->flags &= ~CAM_DEV_REL_TIMEOUT_PENDING;
                        }

                        /*
                         * Now that we are unfrozen schedule the
                         * device so any pending transactions are
                         * run.
                         */
                        if ((dev->ccbq.queue.entries > 0)
                         && (xpt_schedule_dev_sendq(dev->target->bus, dev))
                         && (run_queue != 0)) {
                                rundevq = 1;
                        }
                }
        }
        splx(s1);
        if (rundevq != 0)
                xpt_run_dev_sendq(dev->target->bus);
        splx(s0);
}

void
xpt_release_simq(struct cam_sim *sim, int run_queue)
{
        int     s;
        struct  camq *sendq;

        sendq = &(sim->devq->send_queue);
        s = splcam();
        if (sendq->qfrozen_cnt > 0) {

                sendq->qfrozen_cnt--;
                if (sendq->qfrozen_cnt == 0) {
                        struct cam_eb *bus;

                        /*
                         * If there is a timeout scheduled to release this
                         * sim queue, remove it.  The queue frozen count is
                         * already at 0.
                         */
                        if ((sim->flags & CAM_SIM_REL_TIMEOUT_PENDING) != 0){
                                untimeout(xpt_release_simq_timeout, sim,
                                          sim->c_handle);
                                sim->flags &= ~CAM_SIM_REL_TIMEOUT_PENDING;
                        }
                        bus = xpt_find_bus(sim->path_id);
                        splx(s);

                        if (run_queue) {
                                /*
                                 * Now that we are unfrozen run the send queue.
                                 */
                                xpt_run_dev_sendq(bus);
                        }
                        xpt_release_bus(bus);
                } else
                        splx(s);
        } else
                splx(s);
}

static void
xpt_release_simq_timeout(void *arg)
{
        struct cam_sim *sim;

        sim = (struct cam_sim *)arg;
        xpt_release_simq(sim, /* run_queue */ TRUE);
}

void
xpt_done(union ccb *done_ccb)
{
        int s;

        s = splcam();

        CAM_DEBUG(done_ccb->ccb_h.path, CAM_DEBUG_TRACE, ("xpt_done\n"));
        if ((done_ccb->ccb_h.func_code & XPT_FC_QUEUED) != 0) {
                /*
                 * Queue up the request for handling by our SWI handler
                 * any of the "non-immediate" type of ccbs.
                 */
                switch (done_ccb->ccb_h.path->periph->type) {
                case CAM_PERIPH_BIO:
                        TAILQ_INSERT_TAIL(&cam_bioq, &done_ccb->ccb_h,
                                          sim_links.tqe);
                        done_ccb->ccb_h.pinfo.index = CAM_DONEQ_INDEX;
                        sched_swi(cambio_ih, SWI_NOSWITCH);
                        break;
                case CAM_PERIPH_NET:
                        TAILQ_INSERT_TAIL(&cam_netq, &done_ccb->ccb_h,
                                          sim_links.tqe);
                        done_ccb->ccb_h.pinfo.index = CAM_DONEQ_INDEX;
                        sched_swi(camnet_ih, SWI_NOSWITCH);
                        break;
                }
        }
        splx(s);
}

union ccb *
xpt_alloc_ccb()
{
        union ccb *new_ccb;

        new_ccb = malloc(sizeof(*new_ccb), M_DEVBUF, M_WAITOK);
        return (new_ccb);
}

void
xpt_free_ccb(union ccb *free_ccb)
{
        free(free_ccb, M_DEVBUF);
}



/* Private XPT functions */

/*
 * Get a CAM control block for the caller. Charge the structure to the device
 * referenced by the path.  If the this device has no 'credits' then the
 * device already has the maximum number of outstanding operations under way
 * and we return NULL. If we don't have sufficient resources to allocate more
 * ccbs, we also return NULL.
 */
static union ccb *
xpt_get_ccb(struct cam_ed *device)
{
        union ccb *new_ccb;
        int s;

        s = splsoftcam();
        if ((new_ccb = (union ccb *)SLIST_FIRST(&ccb_freeq)) == NULL) {
                new_ccb = malloc(sizeof(*new_ccb), M_DEVBUF, M_NOWAIT);
                if (new_ccb == NULL) {
                        splx(s);
                        return (NULL);
                }
                callout_handle_init(&new_ccb->ccb_h.timeout_ch);
                SLIST_INSERT_HEAD(&ccb_freeq, &new_ccb->ccb_h,
                                  xpt_links.sle);
                xpt_ccb_count++;
        }
        cam_ccbq_take_opening(&device->ccbq);
        SLIST_REMOVE_HEAD(&ccb_freeq, xpt_links.sle);
        splx(s);
        return (new_ccb);
}

static void
xpt_release_bus(struct cam_eb *bus)
{
        int s;

        s = splcam();
        if ((--bus->refcount == 0)
         && (TAILQ_FIRST(&bus->et_entries) == NULL)) {
                TAILQ_REMOVE(&xpt_busses, bus, links);
                bus_generation++;
                splx(s);
                free(bus, M_DEVBUF);
        } else
                splx(s);
}

static struct cam_et *
xpt_alloc_target(struct cam_eb *bus, target_id_t target_id)
{
        struct cam_et *target;

        target = (struct cam_et *)malloc(sizeof(*target), M_DEVBUF, M_NOWAIT);
        if (target != NULL) {
                struct cam_et *cur_target;

                TAILQ_INIT(&target->ed_entries);
                target->bus = bus;
                target->target_id = target_id;
                target->refcount = 1;
                target->generation = 0;
                timevalclear(&target->last_reset);
                /*
                 * Hold a reference to our parent bus so it
                 * will not go away before we do.
                 */
                bus->refcount++;

                /* Insertion sort into our bus's target list */
                cur_target = TAILQ_FIRST(&bus->et_entries);
                while (cur_target != NULL && cur_target->target_id < target_id)
                        cur_target = TAILQ_NEXT(cur_target, links);

                if (cur_target != NULL) {
                        TAILQ_INSERT_BEFORE(cur_target, target, links);
                } else {
                        TAILQ_INSERT_TAIL(&bus->et_entries, target, links);
                }
                bus->generation++;
        }
        return (target);
}

static void
xpt_release_target(struct cam_eb *bus, struct cam_et *target)
{
        int s;

        s = splcam();
        if ((--target->refcount == 0)
         && (TAILQ_FIRST(&target->ed_entries) == NULL)) {
                TAILQ_REMOVE(&bus->et_entries, target, links);
                bus->generation++;
                splx(s);
                free(target, M_DEVBUF);
                xpt_release_bus(bus);
        } else
                splx(s);
}

static struct cam_ed *
xpt_alloc_device(struct cam_eb *bus, struct cam_et *target, lun_id_t lun_id)
{
        struct     cam_ed *device;
        struct     cam_devq *devq;
        cam_status status;

        /* Make space for us in the device queue on our bus */
        devq = bus->sim->devq;
        status = cam_devq_resize(devq, devq->alloc_queue.array_size + 1);

        if (status != CAM_REQ_CMP) {
                device = NULL;
        } else {
                device = (struct cam_ed *)malloc(sizeof(*device),
                                                 M_DEVBUF, M_NOWAIT);
        }

        if (device != NULL) {
                struct cam_ed *cur_device;

                cam_init_pinfo(&device->alloc_ccb_entry.pinfo);
                device->alloc_ccb_entry.device = device;
                cam_init_pinfo(&device->send_ccb_entry.pinfo);
                device->send_ccb_entry.device = device;
                device->target = target;
                device->lun_id = lun_id;
                /* Initialize our queues */
                if (camq_init(&device->drvq, 0) != 0) {
                        free(device, M_DEVBUF);
                        return (NULL);
                }
                if (cam_ccbq_init(&device->ccbq,
                                  bus->sim->max_dev_openings) != 0) {
                        camq_fini(&device->drvq);
                        free(device, M_DEVBUF);
                        return (NULL);
                }
                SLIST_INIT(&device->asyncs);
                SLIST_INIT(&device->periphs);
                device->generation = 0;
                device->owner = NULL;
                /*
                 * Take the default quirk entry until we have inquiry
                 * data and can determine a better quirk to use.
                 */
                device->quirk = &xpt_quirk_table[xpt_quirk_table_size - 1];
                bzero(&device->inq_data, sizeof(device->inq_data));
                device->inq_flags = 0;
                device->queue_flags = 0;
                device->serial_num = NULL;
                device->serial_num_len = 0;
                device->qfrozen_cnt = 0;
                device->flags = CAM_DEV_UNCONFIGURED;
                device->tag_delay_count = 0;
                device->refcount = 1;
                callout_handle_init(&device->c_handle);

                /*
                 * Hold a reference to our parent target so it
                 * will not go away before we do.
                 */
                target->refcount++;

                /*
                 * XXX should be limited by number of CCBs this bus can
                 * do.
                 */
                xpt_max_ccbs += device->ccbq.devq_openings;
                /* Insertion sort into our target's device list */
                cur_device = TAILQ_FIRST(&target->ed_entries);
                while (cur_device != NULL && cur_device->lun_id < lun_id)
                        cur_device = TAILQ_NEXT(cur_device, links);
                if (cur_device != NULL) {
                        TAILQ_INSERT_BEFORE(cur_device, device, links);
                } else {
                        TAILQ_INSERT_TAIL(&target->ed_entries, device, links);
                }
                target->generation++;
        }
        return (device);
}

static void
xpt_release_device(struct cam_eb *bus, struct cam_et *target,
                   struct cam_ed *device)
{
        int s;

        s = splcam();
        if ((--device->refcount == 0)
         && ((device->flags & CAM_DEV_UNCONFIGURED) != 0)) {
                struct cam_devq *devq;

                if (device->alloc_ccb_entry.pinfo.index != CAM_UNQUEUED_INDEX
                 || device->send_ccb_entry.pinfo.index != CAM_UNQUEUED_INDEX)
                        panic("Removing device while still queued for ccbs");

                if ((device->flags & CAM_DEV_REL_TIMEOUT_PENDING) != 0)
                                untimeout(xpt_release_devq_timeout, device,
                                          device->c_handle);

                TAILQ_REMOVE(&target->ed_entries, device,links);
                target->generation++;
                xpt_max_ccbs -= device->ccbq.devq_openings;
                /* Release our slot in the devq */
                devq = bus->sim->devq;
                cam_devq_resize(devq, devq->alloc_queue.array_size - 1);
                splx(s);
                free(device, M_DEVBUF);
                xpt_release_target(bus, target);
        } else
                splx(s);
}

static u_int32_t
xpt_dev_ccbq_resize(struct cam_path *path, int newopenings)
{
        int     s;
        int     diff;
        int     result;
        struct  cam_ed *dev;

        dev = path->device;
        s = splsoftcam();

        diff = newopenings - (dev->ccbq.dev_active + dev->ccbq.dev_openings);
        result = cam_ccbq_resize(&dev->ccbq, newopenings);
        if (result == CAM_REQ_CMP && (diff < 0)) {
                dev->flags |= CAM_DEV_RESIZE_QUEUE_NEEDED;
        }
        /* Adjust the global limit */
        xpt_max_ccbs += diff;
        splx(s);
        return (result);
}

static struct cam_eb *
xpt_find_bus(path_id_t path_id)
{
        struct cam_eb *bus;

        for (bus = TAILQ_FIRST(&xpt_busses);
             bus != NULL;
             bus = TAILQ_NEXT(bus, links)) {
                if (bus->path_id == path_id) {
                        bus->refcount++;
                        break;
                }
        }
        return (bus);
}

static struct cam_et *
xpt_find_target(struct cam_eb *bus, target_id_t target_id)
{
        struct cam_et *target;

        for (target = TAILQ_FIRST(&bus->et_entries);
             target != NULL;
             target = TAILQ_NEXT(target, links)) {
                if (target->target_id == target_id) {
                        target->refcount++;
                        break;
                }
        }
        return (target);
}

static struct cam_ed *
xpt_find_device(struct cam_et *target, lun_id_t lun_id)
{
        struct cam_ed *device;

        for (device = TAILQ_FIRST(&target->ed_entries);
             device != NULL;
             device = TAILQ_NEXT(device, links)) {
                if (device->lun_id == lun_id) {
                        device->refcount++;
                        break;
                }
        }
        return (device);
}

typedef struct {
        union   ccb *request_ccb;
        struct  ccb_pathinq *cpi;
        int     pending_count;
} xpt_scan_bus_info;

/*
 * To start a scan, request_ccb is an XPT_SCAN_BUS ccb.
 * As the scan progresses, xpt_scan_bus is used as the
 * callback on completion function.
 */
static void
xpt_scan_bus(struct cam_periph *periph, union ccb *request_ccb)
{
        CAM_DEBUG(request_ccb->ccb_h.path, CAM_DEBUG_TRACE,
                  ("xpt_scan_bus\n"));
        switch (request_ccb->ccb_h.func_code) {
        case XPT_SCAN_BUS:
        {
                xpt_scan_bus_info *scan_info;
                union   ccb *work_ccb;
                struct  cam_path *path;
                u_int   i;
                u_int   max_target;
                u_int   initiator_id;

                /* Find out the characteristics of the bus */
                work_ccb = xpt_alloc_ccb();
                xpt_setup_ccb(&work_ccb->ccb_h, request_ccb->ccb_h.path,
                              request_ccb->ccb_h.pinfo.priority);
                work_ccb->ccb_h.func_code = XPT_PATH_INQ;
                xpt_action(work_ccb);
                if (work_ccb->ccb_h.status != CAM_REQ_CMP) {
                        request_ccb->ccb_h.status = work_ccb->ccb_h.status;
                        xpt_free_ccb(work_ccb);
                        xpt_done(request_ccb);
                        return;
                }

                if ((work_ccb->cpi.hba_misc & PIM_NOINITIATOR) != 0) {
                        /*
                         * Can't scan the bus on an adapter that
                         * cannot perform the initiator role.
                         */
                        request_ccb->ccb_h.status = CAM_REQ_CMP;
                        xpt_free_ccb(work_ccb);
                        xpt_done(request_ccb);
                        return;
                }

                /* Save some state for use while we probe for devices */
                scan_info = (xpt_scan_bus_info *)
                    malloc(sizeof(xpt_scan_bus_info), M_TEMP, M_WAITOK);
                scan_info->request_ccb = request_ccb;
                scan_info->cpi = &work_ccb->cpi;

                /* Cache on our stack so we can work asynchronously */
                max_target = scan_info->cpi->max_target;
                initiator_id = scan_info->cpi->initiator_id;

                /*
                 * Don't count the initiator if the
                 * initiator is addressable.
                 */
                scan_info->pending_count = max_target + 1;
                if (initiator_id <= max_target)
                        scan_info->pending_count--;

                for (i = 0; i <= max_target; i++) {
                        cam_status status;
                        if (i == initiator_id)
                                continue;

                        status = xpt_create_path(&path, xpt_periph,
                                                 request_ccb->ccb_h.path_id,
                                                 i, 0);
                        if (status != CAM_REQ_CMP) {
                                printf("xpt_scan_bus: xpt_create_path failed"
                                       " with status %#x, bus scan halted\n",
                                       status);
                                break;
                        }
                        work_ccb = xpt_alloc_ccb();
                        xpt_setup_ccb(&work_ccb->ccb_h, path,
                                      request_ccb->ccb_h.pinfo.priority);
                        work_ccb->ccb_h.func_code = XPT_SCAN_LUN;
                        work_ccb->ccb_h.cbfcnp = xpt_scan_bus;
                        work_ccb->ccb_h.ppriv_ptr0 = scan_info;
                        work_ccb->crcn.flags = request_ccb->crcn.flags;
#if 0
                        printf("xpt_scan_bus: probing %d:%d:%d\n",
                                request_ccb->ccb_h.path_id, i, 0);
#endif
                        xpt_action(work_ccb);
                }
                break;
        }
        case XPT_SCAN_LUN:
        {
                xpt_scan_bus_info *scan_info;
                path_id_t path_id;
                target_id_t target_id;
                lun_id_t lun_id;

                /* Reuse the same CCB to query if a device was really found */
                scan_info = (xpt_scan_bus_info *)request_ccb->ccb_h.ppriv_ptr0;
                xpt_setup_ccb(&request_ccb->ccb_h, request_ccb->ccb_h.path,
                              request_ccb->ccb_h.pinfo.priority);
                request_ccb->ccb_h.func_code = XPT_GDEV_TYPE;

                path_id = request_ccb->ccb_h.path_id;
                target_id = request_ccb->ccb_h.target_id;
                lun_id = request_ccb->ccb_h.target_lun;
                xpt_action(request_ccb);

#if 0
                printf("xpt_scan_bus: got back probe from %d:%d:%d\n",
                        path_id, target_id, lun_id);
#endif

                if (request_ccb->ccb_h.status != CAM_REQ_CMP) {
                        struct cam_ed *device;
                        struct cam_et *target;
                        int s, phl;

                        /*
                         * If we already probed lun 0 successfully, or
                         * we have additional configured luns on this
                         * target that might have "gone away", go onto
                         * the next lun.
                         */
                        target = request_ccb->ccb_h.path->target;
                        /*
                         * We may touch devices that we don't
                         * hold references too, so ensure they
                         * don't disappear out from under us.
                         * The target above is referenced by the
                         * path in the request ccb.
                         */
                        phl = 0;
                        s = splcam();
                        device = TAILQ_FIRST(&target->ed_entries);
                        if (device != NULL) {
                                phl = device->quirk->quirks & CAM_QUIRK_HILUNS;
                                if (device->lun_id == 0)
                                        device = TAILQ_NEXT(device, links);
                        }
                        splx(s);
                        if ((lun_id != 0) || (device != NULL)) {
                                if (lun_id < (CAM_SCSI2_MAXLUN-1) || phl)
                                        lun_id++;
                        }
                } else {
                        struct cam_ed *device;
                        
                        device = request_ccb->ccb_h.path->device;

                        if ((device->quirk->quirks & CAM_QUIRK_NOLUNS) == 0) {
                                /* Try the next lun */
                                if (lun_id < (CAM_SCSI2_MAXLUN-1) ||
                                    (device->quirk->quirks & CAM_QUIRK_HILUNS))
                                        lun_id++;
                        }
                }

                xpt_free_path(request_ccb->ccb_h.path);

                /* Check Bounds */
                if ((lun_id == request_ccb->ccb_h.target_lun)
                 || lun_id > scan_info->cpi->max_lun) {
                        /* We're done */

                        xpt_free_ccb(request_ccb);
                        scan_info->pending_count--;
                        if (scan_info->pending_count == 0) {
                                xpt_free_ccb((union ccb *)scan_info->cpi);
                                request_ccb = scan_info->request_ccb;
                                free(scan_info, M_TEMP);
                                request_ccb->ccb_h.status = CAM_REQ_CMP;
                                xpt_done(request_ccb);
                        }
                } else {
                        /* Try the next device */
                        struct cam_path *path;
                        cam_status status;

                        path = request_ccb->ccb_h.path;
                        status = xpt_create_path(&path, xpt_periph,
                                                 path_id, target_id, lun_id);
                        if (status != CAM_REQ_CMP) {
                                printf("xpt_scan_bus: xpt_create_path failed "
                                       "with status %#x, halting LUN scan\n",
                                       status);
                                xpt_free_ccb(request_ccb);
                                scan_info->pending_count--;
                                if (scan_info->pending_count == 0) {
                                        xpt_free_ccb(
                                                (union ccb *)scan_info->cpi);
                                        request_ccb = scan_info->request_ccb;
                                        free(scan_info, M_TEMP);
                                        request_ccb->ccb_h.status = CAM_REQ_CMP;
                                        xpt_done(request_ccb);
                                        break;
                                }
                        }
                        xpt_setup_ccb(&request_ccb->ccb_h, path,
                                      request_ccb->ccb_h.pinfo.priority);
                        request_ccb->ccb_h.func_code = XPT_SCAN_LUN;
                        request_ccb->ccb_h.cbfcnp = xpt_scan_bus;
                        request_ccb->ccb_h.ppriv_ptr0 = scan_info;
                        request_ccb->crcn.flags =
                                scan_info->request_ccb->crcn.flags;
#if 0
                        xpt_print_path(path);
                        printf("xpt_scan bus probing\n");
#endif
                        xpt_action(request_ccb);
                }
                break;
        }
        default:
                break;
        }
}

typedef enum {
        PROBE_TUR,
        PROBE_INQUIRY,
        PROBE_FULL_INQUIRY,
        PROBE_MODE_SENSE,
        PROBE_SERIAL_NUM,
        PROBE_TUR_FOR_NEGOTIATION
} probe_action;

typedef enum {
        PROBE_INQUIRY_CKSUM     = 0x01,
        PROBE_SERIAL_CKSUM      = 0x02,
        PROBE_NO_ANNOUNCE       = 0x04
} probe_flags;

typedef struct {
        TAILQ_HEAD(, ccb_hdr) request_ccbs;
        probe_action    action;
        union ccb       saved_ccb;
        probe_flags     flags;
        MD5_CTX         context;
        u_int8_t        digest[16];
} probe_softc;

static void
xpt_scan_lun(struct cam_periph *periph, struct cam_path *path,
             cam_flags flags, union ccb *request_ccb)
{
        struct ccb_pathinq cpi;
        cam_status status;
        struct cam_path *new_path;
        struct cam_periph *old_periph;
        int s;
        
        CAM_DEBUG(request_ccb->ccb_h.path, CAM_DEBUG_TRACE,
                  ("xpt_scan_lun\n"));
        
        xpt_setup_ccb(&cpi.ccb_h, path, /*priority*/1);
        cpi.ccb_h.func_code = XPT_PATH_INQ;
        xpt_action((union ccb *)&cpi);

        if (cpi.ccb_h.status != CAM_REQ_CMP) {
                if (request_ccb != NULL) {
                        request_ccb->ccb_h.status = cpi.ccb_h.status;
                        xpt_done(request_ccb);
                }
                return;
        }

        if ((cpi.hba_misc & PIM_NOINITIATOR) != 0) {
                /*
                 * Can't scan the bus on an adapter that
                 * cannot perform the initiator role.
                 */
                if (request_ccb != NULL) {
                        request_ccb->ccb_h.status = CAM_REQ_CMP;
                        xpt_done(request_ccb);
                }
                return;
        }

        if (request_ccb == NULL) {
                request_ccb = malloc(sizeof(union ccb), M_TEMP, M_NOWAIT);
                if (request_ccb == NULL) {
                        xpt_print_path(path);
                        printf("xpt_scan_lun: can't allocate CCB, can't "
                               "continue\n");
                        return;
                }
                new_path = malloc(sizeof(*new_path), M_TEMP, M_NOWAIT);
                if (new_path == NULL) {
                        xpt_print_path(path);
                        printf("xpt_scan_lun: can't allocate path, can't "
                               "continue\n");
                        free(request_ccb, M_TEMP);
                        return;
                }
                status = xpt_compile_path(new_path, xpt_periph,
                                          path->bus->path_id,
                                          path->target->target_id,
                                          path->device->lun_id);

                if (status != CAM_REQ_CMP) {
                        xpt_print_path(path);
                        printf("xpt_scan_lun: can't compile path, can't "
                               "continue\n");
                        free(request_ccb, M_TEMP);
                        free(new_path, M_TEMP);
                        return;
                }
                xpt_setup_ccb(&request_ccb->ccb_h, new_path, /*priority*/ 1);
                request_ccb->ccb_h.cbfcnp = xptscandone;
                request_ccb->ccb_h.func_code = XPT_SCAN_LUN;
                request_ccb->crcn.flags = flags;
        }

        s = splsoftcam();
        if ((old_periph = cam_periph_find(path, "probe")) != NULL) {
                probe_softc *softc;

                softc = (probe_softc *)old_periph->softc;
                TAILQ_INSERT_TAIL(&softc->request_ccbs, &request_ccb->ccb_h,
                                  periph_links.tqe);
        } else {
                status = cam_periph_alloc(proberegister, NULL, probecleanup,
                                          probestart, "probe",
                                          CAM_PERIPH_BIO,
                                          request_ccb->ccb_h.path, NULL, 0,
                                          request_ccb);

                if (status != CAM_REQ_CMP) {
                        xpt_print_path(path);
                        printf("xpt_scan_lun: cam_alloc_periph returned an "
                               "error, can't continue probe\n");
                        request_ccb->ccb_h.status = status;
                        xpt_done(request_ccb);
                }
        }
        splx(s);
}

static void
xptscandone(struct cam_periph *periph, union ccb *done_ccb)
{
        xpt_release_path(done_ccb->ccb_h.path);
        free(done_ccb->ccb_h.path, M_TEMP);
        free(done_ccb, M_TEMP);
}

static cam_status
proberegister(struct cam_periph *periph, void *arg)
{
        union ccb *request_ccb; /* CCB representing the probe request */
        probe_softc *softc;

        request_ccb = (union ccb *)arg;
        if (periph == NULL) {
                printf("proberegister: periph was NULL!!\n");
                return(CAM_REQ_CMP_ERR);
        }

        if (request_ccb == NULL) {
                printf("proberegister: no probe CCB, "
                       "can't register device\n");
                return(CAM_REQ_CMP_ERR);
        }

        softc = (probe_softc *)malloc(sizeof(*softc), M_TEMP, M_NOWAIT);

        if (softc == NULL) {
                printf("proberegister: Unable to probe new device. "
                       "Unable to allocate softc\n");                           
                return(CAM_REQ_CMP_ERR);
        }
        TAILQ_INIT(&softc->request_ccbs);
        TAILQ_INSERT_TAIL(&softc->request_ccbs, &request_ccb->ccb_h,
                          periph_links.tqe);
        softc->flags = 0;
        periph->softc = softc;
        cam_periph_acquire(periph);
        /*
         * Ensure we've waited at least a bus settle
         * delay before attempting to probe the device.
         * For HBAs that don't do bus resets, this won't make a difference.
         */
        cam_periph_freeze_after_event(periph, &periph->path->bus->last_reset,
                                      SCSI_DELAY);
        probeschedule(periph);
        return(CAM_REQ_CMP);
}

static void
probeschedule(struct cam_periph *periph)
{
        struct ccb_pathinq cpi;
        union ccb *ccb;
        probe_softc *softc;

        softc = (probe_softc *)periph->softc;
        ccb = (union ccb *)TAILQ_FIRST(&softc->request_ccbs);

        xpt_setup_ccb(&cpi.ccb_h, periph->path, /*priority*/1);
        cpi.ccb_h.func_code = XPT_PATH_INQ;
        xpt_action((union ccb *)&cpi);

        /*
         * If a device has gone away and another device, or the same one,
         * is back in the same place, it should have a unit attention
         * condition pending.  It will not report the unit attention in
         * response to an inquiry, which may leave invalid transfer
         * negotiations in effect.  The TUR will reveal the unit attention
         * condition.  Only send the TUR for lun 0, since some devices 
         * will get confused by commands other than inquiry to non-existent
         * luns.  If you think a device has gone away start your scan from
         * lun 0.  This will insure that any bogus transfer settings are
         * invalidated.
         *
         * If we haven't seen the device before and the controller supports
         * some kind of transfer negotiation, negotiate with the first
         * sent command if no bus reset was performed at startup.  This
         * ensures that the device is not confused by transfer negotiation
         * settings left over by loader or BIOS action.
         */
        if (((ccb->ccb_h.path->device->flags & CAM_DEV_UNCONFIGURED) == 0)
         && (ccb->ccb_h.target_lun == 0)) {
                softc->action = PROBE_TUR;
        } else if ((cpi.hba_inquiry & (PI_WIDE_32|PI_WIDE_16|PI_SDTR_ABLE)) != 0
              && (cpi.hba_misc & PIM_NOBUSRESET) != 0) {
                proberequestdefaultnegotiation(periph);
                softc->action = PROBE_INQUIRY;
        } else {
                softc->action = PROBE_INQUIRY;
        }

        if (ccb->crcn.flags & CAM_EXPECT_INQ_CHANGE)
                softc->flags |= PROBE_NO_ANNOUNCE;
        else
                softc->flags &= ~PROBE_NO_ANNOUNCE;

        xpt_schedule(periph, ccb->ccb_h.pinfo.priority);
}

static void
probestart(struct cam_periph *periph, union ccb *start_ccb)
{
        /* Probe the device that our peripheral driver points to */
        struct ccb_scsiio *csio;
        probe_softc *softc;

        CAM_DEBUG(start_ccb->ccb_h.path, CAM_DEBUG_TRACE, ("probestart\n"));

        softc = (probe_softc *)periph->softc;
        csio = &start_ccb->csio;

        switch (softc->action) {
        case PROBE_TUR:
        case PROBE_TUR_FOR_NEGOTIATION:
        {
                scsi_test_unit_ready(csio,
                                     /*retries*/4,
                                     probedone,
                                     MSG_SIMPLE_Q_TAG,
                                     SSD_FULL_SIZE,
                                     /*timeout*/60000);
                break;
        }
        case PROBE_INQUIRY:
        case PROBE_FULL_INQUIRY:
        {
                u_int inquiry_len;
                struct scsi_inquiry_data *inq_buf;

                inq_buf = &periph->path->device->inq_data;
                /*
                 * If the device is currently configured, we calculate an
                 * MD5 checksum of the inquiry data, and if the serial number
                 * length is greater than 0, add the serial number data
                 * into the checksum as well.  Once the inquiry and the
                 * serial number check finish, we attempt to figure out
                 * whether we still have the same device.
                 */
                if ((periph->path->device->flags & CAM_DEV_UNCONFIGURED) == 0) {
                        
                        MD5Init(&softc->context);
                        MD5Update(&softc->context, (unsigned char *)inq_buf,
                                  sizeof(struct scsi_inquiry_data));
                        softc->flags |= PROBE_INQUIRY_CKSUM;
                        if (periph->path->device->serial_num_len > 0) {
                                MD5Update(&softc->context,
                                          periph->path->device->serial_num,
                                          periph->path->device->serial_num_len);
                                softc->flags |= PROBE_SERIAL_CKSUM;
                        }
                        MD5Final(softc->digest, &softc->context);
                } 

                if (softc->action == PROBE_INQUIRY)
                        inquiry_len = SHORT_INQUIRY_LENGTH;
                else
                        inquiry_len = inq_buf->additional_length + 4;
        
                scsi_inquiry(csio,
                             /*retries*/4,
                             probedone,
                             MSG_SIMPLE_Q_TAG,
                             (u_int8_t *)inq_buf,
                             inquiry_len,
                             /*evpd*/FALSE,
                             /*page_code*/0,
                             SSD_MIN_SIZE,
                             /*timeout*/60 * 1000);
                break;
        }
        case PROBE_MODE_SENSE:
        {
                void  *mode_buf;
                int    mode_buf_len;

                mode_buf_len = sizeof(struct scsi_mode_header_6)
                             + sizeof(struct scsi_mode_blk_desc)
                             + sizeof(struct scsi_control_page);
                mode_buf = malloc(mode_buf_len, M_TEMP, M_NOWAIT);
                if (mode_buf != NULL) {
                        scsi_mode_sense(csio,
                                        /*retries*/4,
                                        probedone,
                                        MSG_SIMPLE_Q_TAG,
                                        /*dbd*/FALSE,
                                        SMS_PAGE_CTRL_CURRENT,
                                        SMS_CONTROL_MODE_PAGE,
                                        mode_buf,
                                        mode_buf_len,
                                        SSD_FULL_SIZE,
                                        /*timeout*/60000);
                        break;
                }
                xpt_print_path(periph->path);
                printf("Unable to mode sense control page - malloc failure\n");
                softc->action = PROBE_SERIAL_NUM;
                /* FALLTHROUGH */
        }
        case PROBE_SERIAL_NUM:
        {
                struct scsi_vpd_unit_serial_number *serial_buf;
                struct cam_ed* device;

                serial_buf = NULL;
                device = periph->path->device;
                device->serial_num = NULL;
                device->serial_num_len = 0;

                if ((device->quirk->quirks & CAM_QUIRK_NOSERIAL) == 0)
                        serial_buf = (struct scsi_vpd_unit_serial_number *)
                                malloc(sizeof(*serial_buf), M_TEMP,
                                        M_NOWAIT | M_ZERO);

                if (serial_buf != NULL) {
                        scsi_inquiry(csio,
                                     /*retries*/4,
                                     probedone,
                                     MSG_SIMPLE_Q_TAG,
                                     (u_int8_t *)serial_buf,
                                     sizeof(*serial_buf),
                                     /*evpd*/TRUE,
                                     SVPD_UNIT_SERIAL_NUMBER,
                                     SSD_MIN_SIZE,
                                     /*timeout*/60 * 1000);
                        break;
                }
                /*
                 * We'll have to do without, let our probedone
                 * routine finish up for us.
                 */
                start_ccb->csio.data_ptr = NULL;
                probedone(periph, start_ccb);
                return;
        }
        }
        xpt_action(start_ccb);
}

static void
proberequestdefaultnegotiation(struct cam_periph *periph)
{
        struct ccb_trans_settings cts;

        xpt_setup_ccb(&cts.ccb_h, periph->path, /*priority*/1);
        cts.ccb_h.func_code = XPT_GET_TRAN_SETTINGS;
        cts.flags = CCB_TRANS_USER_SETTINGS;
        xpt_action((union ccb *)&cts);
        cts.ccb_h.func_code = XPT_SET_TRAN_SETTINGS;
        cts.flags &= ~CCB_TRANS_USER_SETTINGS;
        cts.flags |= CCB_TRANS_CURRENT_SETTINGS;
        xpt_action((union ccb *)&cts);
}

static void
probedone(struct cam_periph *periph, union ccb *done_ccb)
{
        probe_softc *softc;
        struct cam_path *path;
        u_int32_t  priority;

        CAM_DEBUG(done_ccb->ccb_h.path, CAM_DEBUG_TRACE, ("probedone\n"));

        softc = (probe_softc *)periph->softc;
        path = done_ccb->ccb_h.path;
        priority = done_ccb->ccb_h.pinfo.priority;

        switch (softc->action) {
        case PROBE_TUR:
        {
                if ((done_ccb->ccb_h.status & CAM_STATUS_MASK) != CAM_REQ_CMP) {

                        if (cam_periph_error(done_ccb, 0,
                                             SF_NO_PRINT, NULL) == ERESTART)
                                return;
                        else if ((done_ccb->ccb_h.status & CAM_DEV_QFRZN) != 0)
                                /* Don't wedge the queue */
                                xpt_release_devq(done_ccb->ccb_h.path,
                                                 /*count*/1,
                                                 /*run_queue*/TRUE);
                }
                softc->action = PROBE_INQUIRY;
                xpt_release_ccb(done_ccb);
                xpt_schedule(periph, priority);
                return;
        }
        case PROBE_INQUIRY:
        case PROBE_FULL_INQUIRY:
        {
                if ((done_ccb->ccb_h.status & CAM_STATUS_MASK) == CAM_REQ_CMP) {
                        struct scsi_inquiry_data *inq_buf;
                        u_int8_t periph_qual;
                        u_int8_t periph_dtype;

                        path->device->flags |= CAM_DEV_INQUIRY_DATA_VALID;
                        inq_buf = &path->device->inq_data;

                        periph_qual = SID_QUAL(inq_buf);
                        periph_dtype = SID_TYPE(inq_buf);
                        
                        if (periph_dtype != T_NODEVICE) {
                                switch(periph_qual) {
                                case SID_QUAL_LU_CONNECTED:
                                {
                                        u_int8_t alen;

                                        /*
                                         * We conservatively request only
                                         * SHORT_INQUIRY_LEN bytes of inquiry
                                         * information during our first try
                                         * at sending an INQUIRY. If the device
                                         * has more information to give,
                                         * perform a second request specifying
                                         * the amount of information the device
                                         * is willing to give.
                                         */
                                        alen = inq_buf->additional_length;
                                        if (softc->action == PROBE_INQUIRY
                                         && alen > (SHORT_INQUIRY_LENGTH - 4)) {
                                                softc->action =
                                                    PROBE_FULL_INQUIRY;
                                                xpt_release_ccb(done_ccb);
                                                xpt_schedule(periph, priority);
                                                return;
                                        }

                                        xpt_find_quirk(path->device);

                                        if ((inq_buf->flags & SID_CmdQue) != 0)
                                                softc->action =
                                                    PROBE_MODE_SENSE;
                                        else
                                                softc->action =
                                                    PROBE_SERIAL_NUM;

                                        path->device->flags &= 
                                                ~CAM_DEV_UNCONFIGURED;

                                        xpt_release_ccb(done_ccb);
                                        xpt_schedule(periph, priority);
                                        return;
                                }
                                default:
                                        break;
                                }
                        }
                } else if (cam_periph_error(done_ccb, 0,
                                            done_ccb->ccb_h.target_lun > 0
                                            ? SF_RETRY_UA|SF_QUIET_IR
                                            : SF_RETRY_UA,
                                            &softc->saved_ccb) == ERESTART) {
                        return;
                } else if ((done_ccb->ccb_h.status & CAM_DEV_QFRZN) != 0) {
                        /* Don't wedge the queue */
                        xpt_release_devq(done_ccb->ccb_h.path, /*count*/1,
                                         /*run_queue*/TRUE);
                }
                /*
                 * If we get to this point, we got an error status back
                 * from the inquiry and the error status doesn't require
                 * automatically retrying the command.  Therefore, the
                 * inquiry failed.  If we had inquiry information before
                 * for this device, but this latest inquiry command failed,
                 * the device has probably gone away.  If this device isn't
                 * already marked unconfigured, notify the peripheral
                 * drivers that this device is no more.
                 */
                if ((path->device->flags & CAM_DEV_UNCONFIGURED) == 0)
                        /* Send the async notification. */
                        xpt_async(AC_LOST_DEVICE, path, NULL);

                xpt_release_ccb(done_ccb);
                break;
        }
        case PROBE_MODE_SENSE:
        {
                struct ccb_scsiio *csio;
                struct scsi_mode_header_6 *mode_hdr;

                csio = &done_ccb->csio;
                mode_hdr = (struct scsi_mode_header_6 *)csio->data_ptr;
                if ((csio->ccb_h.status & CAM_STATUS_MASK) == CAM_REQ_CMP) {
                        struct scsi_control_page *page;
                        u_int8_t *offset;

                        offset = ((u_int8_t *)&mode_hdr[1])
                            + mode_hdr->blk_desc_len;
                        page = (struct scsi_control_page *)offset;
                        path->device->queue_flags = page->queue_flags;
                } else if (cam_periph_error(done_ccb, 0,
                                            SF_RETRY_UA|SF_NO_PRINT,
                                            &softc->saved_ccb) == ERESTART) {
                        return;
                } else if ((done_ccb->ccb_h.status & CAM_DEV_QFRZN) != 0) {
                        /* Don't wedge the queue */
                        xpt_release_devq(done_ccb->ccb_h.path,
                                         /*count*/1, /*run_queue*/TRUE);
                }
                xpt_release_ccb(done_ccb);
                free(mode_hdr, M_TEMP);
                softc->action = PROBE_SERIAL_NUM;
                xpt_schedule(periph, priority);
                return;
        }
        case PROBE_SERIAL_NUM:
        {
                struct ccb_scsiio *csio;
                struct scsi_vpd_unit_serial_number *serial_buf;
                u_int32_t  priority;
                int changed;
                int have_serialnum;

                changed = 1;
                have_serialnum = 0;
                csio = &done_ccb->csio;
                priority = done_ccb->ccb_h.pinfo.priority;
                serial_buf =
                    (struct scsi_vpd_unit_serial_number *)csio->data_ptr;

                /* Clean up from previous instance of this device */
                if (path->device->serial_num != NULL) {
                        free(path->device->serial_num, M_DEVBUF);
                        path->device->serial_num = NULL;
                        path->device->serial_num_len = 0;
                }

                if (serial_buf == NULL) {
                        /*
                         * Don't process the command as it was never sent
                         */
                } else if ((csio->ccb_h.status & CAM_STATUS_MASK) == CAM_REQ_CMP
                        && (serial_buf->length > 0)) {

                        have_serialnum = 1;
                        path->device->serial_num =
                                (u_int8_t *)malloc((serial_buf->length + 1),
                                                   M_DEVBUF, M_NOWAIT);
                        if (path->device->serial_num != NULL) {
                                bcopy(serial_buf->serial_num,
                                      path->device->serial_num,
                                      serial_buf->length);
                                path->device->serial_num_len =
                                    serial_buf->length;
                                path->device->serial_num[serial_buf->length]
                                    = '\0';
                        }
                } else if (cam_periph_error(done_ccb, 0,
                                            SF_RETRY_UA|SF_NO_PRINT,
                                            &softc->saved_ccb) == ERESTART) {
                        return;
                } else if ((done_ccb->ccb_h.status & CAM_DEV_QFRZN) != 0) {
                        /* Don't wedge the queue */
                        xpt_release_devq(done_ccb->ccb_h.path, /*count*/1,
                                         /*run_queue*/TRUE);
                }
                
                /*
                 * Let's see if we have seen this device before.
                 */
                if ((softc->flags & PROBE_INQUIRY_CKSUM) != 0) {
                        MD5_CTX context;
                        u_int8_t digest[16];

                        MD5Init(&context);
                        
                        MD5Update(&context,
                                  (unsigned char *)&path->device->inq_data,
                                  sizeof(struct scsi_inquiry_data));

                        if (have_serialnum)
                                MD5Update(&context, serial_buf->serial_num,
                                          serial_buf->length);

                        MD5Final(digest, &context);
                        if (bcmp(softc->digest, digest, 16) == 0)
                                changed = 0;

                        /*
                         * XXX Do we need to do a TUR in order to ensure
                         *     that the device really hasn't changed???
                         */
                        if ((changed != 0)
                         && ((softc->flags & PROBE_NO_ANNOUNCE) == 0))
                                xpt_async(AC_LOST_DEVICE, path, NULL);
                }
                if (serial_buf != NULL)
                        free(serial_buf, M_TEMP);

                if (changed != 0) {
                        /*
                         * Now that we have all the necessary
                         * information to safely perform transfer
                         * negotiations... Controllers don't perform
                         * any negotiation or tagged queuing until
                         * after the first XPT_SET_TRAN_SETTINGS ccb is
                         * received.  So, on a new device, just retreive
                         * the user settings, and set them as the current
                         * settings to set the device up.
                         */
                        proberequestdefaultnegotiation(periph);
                        xpt_release_ccb(done_ccb);

                        /*
                         * Perform a TUR to allow the controller to
                         * perform any necessary transfer negotiation.
                         */
                        softc->action = PROBE_TUR_FOR_NEGOTIATION;
                        xpt_schedule(periph, priority);
                        return;
                }
                xpt_release_ccb(done_ccb);
                break;
        }
        case PROBE_TUR_FOR_NEGOTIATION:
                if ((done_ccb->ccb_h.status & CAM_DEV_QFRZN) != 0) {
                        /* Don't wedge the queue */
                        xpt_release_devq(done_ccb->ccb_h.path, /*count*/1,
                                         /*run_queue*/TRUE);
                }

                path->device->flags &= ~CAM_DEV_UNCONFIGURED;

                if ((softc->flags & PROBE_NO_ANNOUNCE) == 0) {
                        /* Inform the XPT that a new device has been found */
                        done_ccb->ccb_h.func_code = XPT_GDEV_TYPE;
                        xpt_action(done_ccb);

                        xpt_async(AC_FOUND_DEVICE, xpt_periph->path, done_ccb);
                }
                xpt_release_ccb(done_ccb);
                break;
        }
        done_ccb = (union ccb *)TAILQ_FIRST(&softc->request_ccbs);
        TAILQ_REMOVE(&softc->request_ccbs, &done_ccb->ccb_h, periph_links.tqe);
        done_ccb->ccb_h.status = CAM_REQ_CMP;
        xpt_done(done_ccb);
        if (TAILQ_FIRST(&softc->request_ccbs) == NULL) {
                cam_periph_invalidate(periph);
                cam_periph_release(periph);
        } else {
                probeschedule(periph);
        }
}

static void
probecleanup(struct cam_periph *periph)
{
        free(periph->softc, M_TEMP);
}

static void
xpt_find_quirk(struct cam_ed *device)
{
        caddr_t match;

        match = cam_quirkmatch((caddr_t)&device->inq_data,
                               (caddr_t)xpt_quirk_table,
                               sizeof(xpt_quirk_table)/sizeof(*xpt_quirk_table),
                               sizeof(*xpt_quirk_table), scsi_inquiry_match);

        if (match == NULL)
                panic("xpt_find_quirk: device didn't match wildcard entry!!");

        device->quirk = (struct xpt_quirk_entry *)match;
}

static void
xpt_set_transfer_settings(struct ccb_trans_settings *cts, struct cam_ed *device,
                          int async_update)
{
        struct  cam_sim *sim;
        int     qfrozen;

        sim = cts->ccb_h.path->bus->sim;
        if (async_update == FALSE) {
                struct  scsi_inquiry_data *inq_data;
                struct  ccb_pathinq cpi;
                struct  ccb_trans_settings cur_cts;

                if (device == NULL) {
                        cts->ccb_h.status = CAM_PATH_INVALID;
                        xpt_done((union ccb *)cts);
                        return;
                }

                /*
                 * Perform sanity checking against what the
                 * controller and device can do.
                 */
                xpt_setup_ccb(&cpi.ccb_h, cts->ccb_h.path, /*priority*/1);
                cpi.ccb_h.func_code = XPT_PATH_INQ;
                xpt_action((union ccb *)&cpi);
                xpt_setup_ccb(&cur_cts.ccb_h, cts->ccb_h.path, /*priority*/1);
                cur_cts.ccb_h.func_code = XPT_GET_TRAN_SETTINGS;
                cur_cts.flags = CCB_TRANS_CURRENT_SETTINGS;
                xpt_action((union ccb *)&cur_cts);
                inq_data = &device->inq_data;

                /* Fill in any gaps in what the user gave us */
                if ((cts->valid & CCB_TRANS_SYNC_RATE_VALID) == 0)
                        cts->sync_period = cur_cts.sync_period;
                if ((cts->valid & CCB_TRANS_SYNC_OFFSET_VALID) == 0)
                        cts->sync_offset = cur_cts.sync_offset;
                if ((cts->valid & CCB_TRANS_BUS_WIDTH_VALID) == 0)
                        cts->bus_width = cur_cts.bus_width;
                if ((cts->valid & CCB_TRANS_DISC_VALID) == 0) {
                        cts->flags &= ~CCB_TRANS_DISC_ENB;
                        cts->flags |= cur_cts.flags & CCB_TRANS_DISC_ENB;
                }
                if ((cts->valid & CCB_TRANS_TQ_VALID) == 0) {
                        cts->flags &= ~CCB_TRANS_TAG_ENB;
                        cts->flags |= cur_cts.flags & CCB_TRANS_TAG_ENB;
                }
                if (((device->flags & CAM_DEV_INQUIRY_DATA_VALID) != 0
                  && (inq_data->flags & SID_Sync) == 0)
                 || (cpi.hba_inquiry & PI_SDTR_ABLE) == 0) {
                        /* Force async */
                        cts->sync_period = 0;
                        cts->sync_offset = 0;
                }

                /*
                 * Don't allow DT transmission rates if the
                 * device does not support it.
                 */
                if ((device->flags & CAM_DEV_INQUIRY_DATA_VALID) != 0
                 && (inq_data->spi3data & SID_SPI_CLOCK_DT) == 0
                 && cts->sync_period <= 0x9)
                        cts->sync_period = 0xa;

                switch (cts->bus_width) {
                case MSG_EXT_WDTR_BUS_32_BIT:
                        if (((device->flags & CAM_DEV_INQUIRY_DATA_VALID) == 0
                          || (inq_data->flags & SID_WBus32) != 0)
                         && (cpi.hba_inquiry & PI_WIDE_32) != 0)
                                break;
                        /* Fall Through to 16-bit */
                case MSG_EXT_WDTR_BUS_16_BIT:
                        if (((device->flags & CAM_DEV_INQUIRY_DATA_VALID) == 0
                          || (inq_data->flags & SID_WBus16) != 0)
                         && (cpi.hba_inquiry & PI_WIDE_16) != 0) {
                                cts->bus_width = MSG_EXT_WDTR_BUS_16_BIT;
                                break;
                        }
                        /* Fall Through to 8-bit */
                default: /* New bus width?? */
                case MSG_EXT_WDTR_BUS_8_BIT:
                        /* All targets can do this */
                        cts->bus_width = MSG_EXT_WDTR_BUS_8_BIT;
                        break;
                }

                if ((cts->flags & CCB_TRANS_DISC_ENB) == 0) {
                        /*
                         * Can't tag queue without disconnection.
                         */
                        cts->flags &= ~CCB_TRANS_TAG_ENB;
                        cts->valid |= CCB_TRANS_TQ_VALID;
                }

                if ((cpi.hba_inquiry & PI_TAG_ABLE) == 0
                 || (inq_data->flags & SID_CmdQue) == 0
                 || (device->queue_flags & SCP_QUEUE_DQUE) != 0
                 || (device->quirk->mintags == 0)) {
                        /*
                         * Can't tag on hardware that doesn't support,
                         * doesn't have it enabled, or has broken tag support.
                         */
                        cts->flags &= ~CCB_TRANS_TAG_ENB;
                }
        }

        qfrozen = FALSE;
        if ((cts->valid & CCB_TRANS_TQ_VALID) != 0) {
                int device_tagenb;

                /*
                 * If we are transitioning from tags to no-tags or
                 * vice-versa, we need to carefully freeze and restart
                 * the queue so that we don't overlap tagged and non-tagged
                 * commands.  We also temporarily stop tags if there is
                 * a change in transfer negotiation settings to allow
                 * "tag-less" negotiation.
                 */
                if ((device->flags & CAM_DEV_TAG_AFTER_COUNT) != 0
                 || (device->inq_flags & SID_CmdQue) != 0)
                        device_tagenb = TRUE;
                else
                        device_tagenb = FALSE;

                if (((cts->flags & CCB_TRANS_TAG_ENB) != 0
                  && device_tagenb == FALSE)
                 || ((cts->flags & CCB_TRANS_TAG_ENB) == 0
                  && device_tagenb == TRUE)) {

                        if ((cts->flags & CCB_TRANS_TAG_ENB) != 0) {
                                /*
                                 * Delay change to use tags until after a
                                 * few commands have gone to this device so
                                 * the controller has time to perform transfer
                                 * negotiations without tagged messages getting
                                 * in the way.
                                 */
                                device->tag_delay_count = CAM_TAG_DELAY_COUNT;
                                device->flags |= CAM_DEV_TAG_AFTER_COUNT;
                        } else {
                                xpt_freeze_devq(cts->ccb_h.path, /*count*/1);
                                qfrozen = TRUE;
                                device->inq_flags &= ~SID_CmdQue;
                                xpt_dev_ccbq_resize(cts->ccb_h.path,
                                                    sim->max_dev_openings);
                                device->flags &= ~CAM_DEV_TAG_AFTER_COUNT;
                                device->tag_delay_count = 0;
                        }
                }
        }

        if (async_update == FALSE) {
                /*
                 * If we are currently performing tagged transactions to
                 * this device and want to change its negotiation parameters,
                 * go non-tagged for a bit to give the controller a chance to
                 * negotiate unhampered by tag messages.
                 */
                if ((device->inq_flags & SID_CmdQue) != 0
                 && (cts->flags & (CCB_TRANS_SYNC_RATE_VALID|
                                   CCB_TRANS_SYNC_OFFSET_VALID|
                                   CCB_TRANS_BUS_WIDTH_VALID)) != 0)
                        xpt_toggle_tags(cts->ccb_h.path);

                (*(sim->sim_action))(sim, (union ccb *)cts);
        }

        if (qfrozen) {
                struct ccb_relsim crs;

                xpt_setup_ccb(&crs.ccb_h, cts->ccb_h.path,
                              /*priority*/1);
                crs.ccb_h.func_code = XPT_REL_SIMQ;
                crs.release_flags = RELSIM_RELEASE_AFTER_QEMPTY;
                crs.openings
                    = crs.release_timeout 
                    = crs.qfrozen_cnt
                    = 0;
                xpt_action((union ccb *)&crs);
        }
}

static void
xpt_toggle_tags(struct cam_path *path)
{
        struct cam_ed *dev;

        /*
         * Give controllers a chance to renegotiate
         * before starting tag operations.  We
         * "toggle" tagged queuing off then on
         * which causes the tag enable command delay
         * counter to come into effect.
         */
        dev = path->device;
        if ((dev->flags & CAM_DEV_TAG_AFTER_COUNT) != 0
         || ((dev->inq_flags & SID_CmdQue) != 0
          && (dev->inq_flags & (SID_Sync|SID_WBus16|SID_WBus32)) != 0)) {
                struct ccb_trans_settings cts;

                xpt_setup_ccb(&cts.ccb_h, path, 1);
                cts.flags = 0;
                cts.valid = CCB_TRANS_TQ_VALID;
                xpt_set_transfer_settings(&cts, path->device,
                                          /*async_update*/TRUE);
                cts.flags = CCB_TRANS_TAG_ENB;
                xpt_set_transfer_settings(&cts, path->device,
                                          /*async_update*/TRUE);
        }
}

static void
xpt_start_tags(struct cam_path *path)
{
        struct ccb_relsim crs;
        struct cam_ed *device;
        struct cam_sim *sim;
        int    newopenings;

        device = path->device;
        sim = path->bus->sim;
        device->flags &= ~CAM_DEV_TAG_AFTER_COUNT;
        xpt_freeze_devq(path, /*count*/1);
        device->inq_flags |= SID_CmdQue;
        newopenings = min(device->quirk->maxtags, sim->max_tagged_dev_openings);
        xpt_dev_ccbq_resize(path, newopenings);
        xpt_setup_ccb(&crs.ccb_h, path, /*priority*/1);
        crs.ccb_h.func_code = XPT_REL_SIMQ;
        crs.release_flags = RELSIM_RELEASE_AFTER_QEMPTY;
        crs.openings
            = crs.release_timeout 
            = crs.qfrozen_cnt
            = 0;
        xpt_action((union ccb *)&crs);
}

static int busses_to_config;
static int busses_to_reset;

static int
xptconfigbuscountfunc(struct cam_eb *bus, void *arg)
{
        if (bus->path_id != CAM_XPT_PATH_ID) {
                struct cam_path path;
                struct ccb_pathinq cpi;
                int can_negotiate;

                busses_to_config++;
                xpt_compile_path(&path, NULL, bus->path_id,
                                 CAM_TARGET_WILDCARD, CAM_LUN_WILDCARD);
                xpt_setup_ccb(&cpi.ccb_h, &path, /*priority*/1);
                cpi.ccb_h.func_code = XPT_PATH_INQ;
                xpt_action((union ccb *)&cpi);
                can_negotiate = cpi.hba_inquiry;
                can_negotiate &= (PI_WIDE_32|PI_WIDE_16|PI_SDTR_ABLE);
                if ((cpi.hba_misc & PIM_NOBUSRESET) == 0
                 && can_negotiate)
                        busses_to_reset++;
                xpt_release_path(&path);
        }

        return(1);
}

static int
xptconfigfunc(struct cam_eb *bus, void *arg)
{
        struct  cam_path *path;
        union   ccb *work_ccb;

        if (bus->path_id != CAM_XPT_PATH_ID) {
                cam_status status;
                int can_negotiate;

                work_ccb = xpt_alloc_ccb();
                if ((status = xpt_create_path(&path, xpt_periph, bus->path_id,
                                              CAM_TARGET_WILDCARD,
                                              CAM_LUN_WILDCARD)) !=CAM_REQ_CMP){
                        printf("xptconfigfunc: xpt_create_path failed with "
                               "status %#x for bus %d\n", status, bus->path_id);
                        printf("xptconfigfunc: halting bus configuration\n");
                        xpt_free_ccb(work_ccb);
                        busses_to_config--;
                        xpt_finishconfig(xpt_periph, NULL);
                        return(0);
                }
                xpt_setup_ccb(&work_ccb->ccb_h, path, /*priority*/1);
                work_ccb->ccb_h.func_code = XPT_PATH_INQ;
                xpt_action(work_ccb);
                if (work_ccb->ccb_h.status != CAM_REQ_CMP) {
                        printf("xptconfigfunc: CPI failed on bus %d "
                               "with status %d\n", bus->path_id,
                               work_ccb->ccb_h.status);
                        xpt_finishconfig(xpt_periph, work_ccb);
                        return(1);
                }

                can_negotiate = work_ccb->cpi.hba_inquiry;
                can_negotiate &= (PI_WIDE_32|PI_WIDE_16|PI_SDTR_ABLE);
                if ((work_ccb->cpi.hba_misc & PIM_NOBUSRESET) == 0
                 && (can_negotiate != 0)) {
                        xpt_setup_ccb(&work_ccb->ccb_h, path, /*priority*/1);
                        work_ccb->ccb_h.func_code = XPT_RESET_BUS;
                        work_ccb->ccb_h.cbfcnp = NULL;
                        CAM_DEBUG(path, CAM_DEBUG_SUBTRACE,
                                  ("Resetting Bus\n"));
                        xpt_action(work_ccb);
                        xpt_finishconfig(xpt_periph, work_ccb);
                } else {
                        /* Act as though we performed a successful BUS RESET */
                        work_ccb->ccb_h.func_code = XPT_RESET_BUS;
                        xpt_finishconfig(xpt_periph, work_ccb);
                }
        }

        return(1);
}

static void
xpt_config(void *arg)
{
        /* Now that interrupts are enabled, go find our devices */

#ifdef CAMDEBUG
        /* Setup debugging flags and path */
#ifdef CAM_DEBUG_FLAGS
        cam_dflags = CAM_DEBUG_FLAGS;
#else /* !CAM_DEBUG_FLAGS */
        cam_dflags = CAM_DEBUG_NONE;
#endif /* CAM_DEBUG_FLAGS */
#ifdef CAM_DEBUG_BUS
        if (cam_dflags != CAM_DEBUG_NONE) {
                if (xpt_create_path(&cam_dpath, xpt_periph,
                                    CAM_DEBUG_BUS, CAM_DEBUG_TARGET,
                                    CAM_DEBUG_LUN) != CAM_REQ_CMP) {
                        printf("xpt_config: xpt_create_path() failed for debug"
                               " target %d:%d:%d, debugging disabled\n",
                               CAM_DEBUG_BUS, CAM_DEBUG_TARGET, CAM_DEBUG_LUN);
                        cam_dflags = CAM_DEBUG_NONE;
                }
        } else
                cam_dpath = NULL;
#else /* !CAM_DEBUG_BUS */
        cam_dpath = NULL;
#endif /* CAM_DEBUG_BUS */
#endif /* CAMDEBUG */

        /*
         * Scan all installed busses.
         */
        xpt_for_all_busses(xptconfigbuscountfunc, NULL);

        if (busses_to_config == 0) {
                /* Call manually because we don't have any busses */
                xpt_finishconfig(xpt_periph, NULL);
        } else  {
                if (busses_to_reset > 0 && SCSI_DELAY >= 2000) {
                        printf("Waiting %d seconds for SCSI "
                               "devices to settle\n", SCSI_DELAY/1000);
                }
                xpt_for_all_busses(xptconfigfunc, NULL);
        }
}

/*
 * If the given device only has one peripheral attached to it, and if that
 * peripheral is the passthrough driver, announce it.  This insures that the
 * user sees some sort of announcement for every peripheral in their system.
 */
static int
xptpassannouncefunc(struct cam_ed *device, void *arg)
{
        struct cam_periph *periph;
        int i;

        for (periph = SLIST_FIRST(&device->periphs), i = 0; periph != NULL;
             periph = SLIST_NEXT(periph, periph_links), i++);

        periph = SLIST_FIRST(&device->periphs);
        if ((i == 1)
         && (strncmp(periph->periph_name, "pass", 4) == 0))
                xpt_announce_periph(periph, NULL);

        return(1);
}

static void
xpt_finishconfig(struct cam_periph *periph, union ccb *done_ccb)
{
        struct  periph_driver **p_drv;
        int     i;

        if (done_ccb != NULL) {
                CAM_DEBUG(done_ccb->ccb_h.path, CAM_DEBUG_TRACE,
                          ("xpt_finishconfig\n"));
                switch(done_ccb->ccb_h.func_code) {
                case XPT_RESET_BUS:
                        if (done_ccb->ccb_h.status == CAM_REQ_CMP) {
                                done_ccb->ccb_h.func_code = XPT_SCAN_BUS;
                                done_ccb->ccb_h.cbfcnp = xpt_finishconfig;
                                xpt_action(done_ccb);
                                return;
                        }
                        /* FALLTHROUGH */
                case XPT_SCAN_BUS:
                default:
                        xpt_free_path(done_ccb->ccb_h.path);
                        busses_to_config--;
                        break;
                }
        }

        if (busses_to_config == 0) {
                /* Register all the peripheral drivers */
                /* XXX This will have to change when we have loadable modules */
                p_drv = (struct periph_driver **)periphdriver_set.ls_items;
                for (i = 0; p_drv[i] != NULL; i++) {
                        (*p_drv[i]->init)();
                }

                /*
                 * Check for devices with no "standard" peripheral driver
                 * attached.  For any devices like that, announce the
                 * passthrough driver so the user will see something.
                 */
                xpt_for_all_devices(xptpassannouncefunc, NULL);

                /* Release our hook so that the boot can continue. */
                config_intrhook_disestablish(xpt_config_hook);
                free(xpt_config_hook, M_TEMP);
                xpt_config_hook = NULL;
        }
        if (done_ccb != NULL)
                xpt_free_ccb(done_ccb);
}

static void
xptaction(struct cam_sim *sim, union ccb *work_ccb)
{
        CAM_DEBUG(work_ccb->ccb_h.path, CAM_DEBUG_TRACE, ("xptaction\n"));

        switch (work_ccb->ccb_h.func_code) {
        /* Common cases first */
        case XPT_PATH_INQ:              /* Path routing inquiry */
        {
                struct ccb_pathinq *cpi;

                cpi = &work_ccb->cpi;
                cpi->version_num = 1; /* XXX??? */
                cpi->hba_inquiry = 0;
                cpi->target_sprt = 0;
                cpi->hba_misc = 0;
                cpi->hba_eng_cnt = 0;
                cpi->max_target = 0;
                cpi->max_lun = 0;
                cpi->initiator_id = 0;
                strncpy(cpi->sim_vid, "FreeBSD", SIM_IDLEN);
                strncpy(cpi->hba_vid, "", HBA_IDLEN);
                strncpy(cpi->dev_name, sim->sim_name, DEV_IDLEN);
                cpi->unit_number = sim->unit_number;
                cpi->bus_id = sim->bus_id;
                cpi->base_transfer_speed = 0;
                cpi->ccb_h.status = CAM_REQ_CMP;
                xpt_done(work_ccb);
                break;
        }
        default:
                work_ccb->ccb_h.status = CAM_REQ_INVALID;
                xpt_done(work_ccb);
                break;
        }
}

/*
 * The xpt as a "controller" has no interrupt sources, so polling
 * is a no-op.
 */
static void
xptpoll(struct cam_sim *sim)
{
}

static void
camisr(void *V_queue)
{
        cam_isrq_t *queue = V_queue;
        int     s;
        struct  ccb_hdr *ccb_h;

        s = splcam();
        while ((ccb_h = TAILQ_FIRST(queue)) != NULL) {
                int     runq;

                TAILQ_REMOVE(queue, ccb_h, sim_links.tqe);
                ccb_h->pinfo.index = CAM_UNQUEUED_INDEX;
                splx(s);

                CAM_DEBUG(ccb_h->path, CAM_DEBUG_TRACE,
                          ("camisr"));

                runq = FALSE;

                if (ccb_h->flags & CAM_HIGH_POWER) {
                        struct highpowerlist    *hphead;
                        struct cam_ed           *device;
                        union ccb               *send_ccb;

                        hphead = &highpowerq;

                        send_ccb = (union ccb *)STAILQ_FIRST(hphead);

                        /*
                         * Increment the count since this command is done.
                         */
                        num_highpower++;

                        /* 
                         * Any high powered commands queued up?
                         */
                        if (send_ccb != NULL) {
                                device = send_ccb->ccb_h.path->device;

                                STAILQ_REMOVE_HEAD(hphead, xpt_links.stqe);

                                xpt_release_devq(send_ccb->ccb_h.path,
                                                 /*count*/1, /*runqueue*/TRUE);
                        }
                }
                if ((ccb_h->func_code & XPT_FC_USER_CCB) == 0) {
                        struct cam_ed *dev;

                        dev = ccb_h->path->device;

                        s = splcam();
                        cam_ccbq_ccb_done(&dev->ccbq, (union ccb *)ccb_h);

                        ccb_h->path->bus->sim->devq->send_active--;
                        ccb_h->path->bus->sim->devq->send_openings++;
                        splx(s);
                        
                        if ((dev->flags & CAM_DEV_REL_ON_COMPLETE) != 0
                         || ((dev->flags & CAM_DEV_REL_ON_QUEUE_EMPTY) != 0
                          && (dev->ccbq.dev_active == 0))) {
                                
                                xpt_release_devq(ccb_h->path, /*count*/1,
                                                 /*run_queue*/TRUE);
                        }

                        if ((dev->flags & CAM_DEV_TAG_AFTER_COUNT) != 0
                         && (--dev->tag_delay_count == 0))
                                xpt_start_tags(ccb_h->path);

                        if ((dev->ccbq.queue.entries > 0)
                         && (dev->qfrozen_cnt == 0)
                         && (device_is_send_queued(dev) == 0)) {
                                runq = xpt_schedule_dev_sendq(ccb_h->path->bus,
                                                              dev);
                        }
                }

                if (ccb_h->status & CAM_RELEASE_SIMQ) {
                        xpt_release_simq(ccb_h->path->bus->sim,
                                         /*run_queue*/TRUE);
                        ccb_h->status &= ~CAM_RELEASE_SIMQ;
                        runq = FALSE;
                } 

                if ((ccb_h->flags & CAM_DEV_QFRZDIS)
                 && (ccb_h->status & CAM_DEV_QFRZN)) {
                        xpt_release_devq(ccb_h->path, /*count*/1,
                                         /*run_queue*/TRUE);
                        ccb_h->status &= ~CAM_DEV_QFRZN;
                } else if (runq) {
                        xpt_run_dev_sendq(ccb_h->path->bus);
                }

                /* Call the peripheral driver's callback */
                (*ccb_h->cbfcnp)(ccb_h->path->periph, (union ccb *)ccb_h);

                /* Raise IPL for while test */
                s = splcam();
        }
        splx(s);
}