Merge ACPICA 20191018.

[FreeBSD/FreeBSD.git] / sys / dev / mpr / mpr.c

/*-
 * Copyright (c) 2009 Yahoo! Inc.
 * Copyright (c) 2011-2015 LSI Corp.
 * Copyright (c) 2013-2016 Avago Technologies
 * Copyright 2000-2020 Broadcom Inc.
 * 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.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * 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.
 *
 * Broadcom Inc. (LSI) MPT-Fusion Host Adapter FreeBSD
 *
 */

#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");

/* Communications core for Avago Technologies (LSI) MPT3 */

/* TODO Move headers to mprvar */
#include <sys/types.h>
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/selinfo.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/module.h>
#include <sys/bus.h>
#include <sys/conf.h>
#include <sys/bio.h>
#include <sys/malloc.h>
#include <sys/uio.h>
#include <sys/sysctl.h>
#include <sys/smp.h>
#include <sys/queue.h>
#include <sys/kthread.h>
#include <sys/taskqueue.h>
#include <sys/endian.h>
#include <sys/eventhandler.h>
#include <sys/sbuf.h>
#include <sys/priv.h>

#include <machine/bus.h>
#include <machine/resource.h>
#include <sys/rman.h>
#include <sys/proc.h>

#include <dev/pci/pcivar.h>

#include <cam/cam.h>
#include <cam/cam_ccb.h>
#include <cam/scsi/scsi_all.h>

#include <dev/mpr/mpi/mpi2_type.h>
#include <dev/mpr/mpi/mpi2.h>
#include <dev/mpr/mpi/mpi2_ioc.h>
#include <dev/mpr/mpi/mpi2_sas.h>
#include <dev/mpr/mpi/mpi2_pci.h>
#include <dev/mpr/mpi/mpi2_cnfg.h>
#include <dev/mpr/mpi/mpi2_init.h>
#include <dev/mpr/mpi/mpi2_tool.h>
#include <dev/mpr/mpr_ioctl.h>
#include <dev/mpr/mprvar.h>
#include <dev/mpr/mpr_table.h>
#include <dev/mpr/mpr_sas.h>

static int mpr_diag_reset(struct mpr_softc *sc, int sleep_flag);
static int mpr_init_queues(struct mpr_softc *sc);
static void mpr_resize_queues(struct mpr_softc *sc);
static int mpr_message_unit_reset(struct mpr_softc *sc, int sleep_flag);
static int mpr_transition_operational(struct mpr_softc *sc);
static int mpr_iocfacts_allocate(struct mpr_softc *sc, uint8_t attaching);
static void mpr_iocfacts_free(struct mpr_softc *sc);
static void mpr_startup(void *arg);
static int mpr_send_iocinit(struct mpr_softc *sc);
static int mpr_alloc_queues(struct mpr_softc *sc);
static int mpr_alloc_hw_queues(struct mpr_softc *sc);
static int mpr_alloc_replies(struct mpr_softc *sc);
static int mpr_alloc_requests(struct mpr_softc *sc);
static int mpr_alloc_nvme_prp_pages(struct mpr_softc *sc);
static int mpr_attach_log(struct mpr_softc *sc);
static __inline void mpr_complete_command(struct mpr_softc *sc,
    struct mpr_command *cm);
static void mpr_dispatch_event(struct mpr_softc *sc, uintptr_t data,
    MPI2_EVENT_NOTIFICATION_REPLY *reply);
static void mpr_config_complete(struct mpr_softc *sc, struct mpr_command *cm);
static void mpr_periodic(void *);
static int mpr_reregister_events(struct mpr_softc *sc);
static void mpr_enqueue_request(struct mpr_softc *sc, struct mpr_command *cm);
static int mpr_get_iocfacts(struct mpr_softc *sc, MPI2_IOC_FACTS_REPLY *facts);
static int mpr_wait_db_ack(struct mpr_softc *sc, int timeout, int sleep_flag);
static int mpr_debug_sysctl(SYSCTL_HANDLER_ARGS);
static int mpr_dump_reqs(SYSCTL_HANDLER_ARGS);
static void mpr_parse_debug(struct mpr_softc *sc, char *list);

SYSCTL_NODE(_hw, OID_AUTO, mpr, CTLFLAG_RD, 0, "MPR Driver Parameters");

MALLOC_DEFINE(M_MPR, "mpr", "mpr driver memory");

/*
 * Do a "Diagnostic Reset" aka a hard reset.  This should get the chip out of
 * any state and back to its initialization state machine.
 */
static char mpt2_reset_magic[] = { 0x00, 0x0f, 0x04, 0x0b, 0x02, 0x07, 0x0d };

/* 
 * Added this union to smoothly convert le64toh cm->cm_desc.Words.
 * Compiler only supports uint64_t to be passed as an argument.
 * Otherwise it will throw this error:
 * "aggregate value used where an integer was expected"
 */
typedef union _reply_descriptor {
        u64 word;
        struct {
                u32 low;
                u32 high;
        } u;
} reply_descriptor, request_descriptor;

/* Rate limit chain-fail messages to 1 per minute */
static struct timeval mpr_chainfail_interval = { 60, 0 };

/* 
 * sleep_flag can be either CAN_SLEEP or NO_SLEEP.
 * If this function is called from process context, it can sleep
 * and there is no harm to sleep, in case if this fuction is called
 * from Interrupt handler, we can not sleep and need NO_SLEEP flag set.
 * based on sleep flags driver will call either msleep, pause or DELAY.
 * msleep and pause are of same variant, but pause is used when mpr_mtx
 * is not hold by driver.
 */
static int
mpr_diag_reset(struct mpr_softc *sc,int sleep_flag)
{
        uint32_t reg;
        int i, error, tries = 0;
        uint8_t first_wait_done = FALSE;

        mpr_dprint(sc, MPR_INIT, "%s entered\n", __func__);

        /* Clear any pending interrupts */
        mpr_regwrite(sc, MPI2_HOST_INTERRUPT_STATUS_OFFSET, 0x0);

        /*
         * Force NO_SLEEP for threads prohibited to sleep
         * e.a Thread from interrupt handler are prohibited to sleep.
         */
#if __FreeBSD_version >= 1000029
        if (curthread->td_no_sleeping)
#else //__FreeBSD_version < 1000029
        if (curthread->td_pflags & TDP_NOSLEEPING)
#endif //__FreeBSD_version >= 1000029
                sleep_flag = NO_SLEEP;

        mpr_dprint(sc, MPR_INIT, "sequence start, sleep_flag=%d\n", sleep_flag);
        /* Push the magic sequence */
        error = ETIMEDOUT;
        while (tries++ < 20) {
                for (i = 0; i < sizeof(mpt2_reset_magic); i++)
                        mpr_regwrite(sc, MPI2_WRITE_SEQUENCE_OFFSET,
                            mpt2_reset_magic[i]);

                /* wait 100 msec */
                if (mtx_owned(&sc->mpr_mtx) && sleep_flag == CAN_SLEEP)
                        msleep(&sc->msleep_fake_chan, &sc->mpr_mtx, 0,
                            "mprdiag", hz/10);
                else if (sleep_flag == CAN_SLEEP)
                        pause("mprdiag", hz/10);
                else
                        DELAY(100 * 1000);

                reg = mpr_regread(sc, MPI2_HOST_DIAGNOSTIC_OFFSET);
                if (reg & MPI2_DIAG_DIAG_WRITE_ENABLE) {
                        error = 0;
                        break;
                }
        }
        if (error) {
                mpr_dprint(sc, MPR_INIT, "sequence failed, error=%d, exit\n",
                    error);
                return (error);
        }

        /* Send the actual reset.  XXX need to refresh the reg? */
        reg |= MPI2_DIAG_RESET_ADAPTER;
        mpr_dprint(sc, MPR_INIT, "sequence success, sending reset, reg= 0x%x\n",
            reg);
        mpr_regwrite(sc, MPI2_HOST_DIAGNOSTIC_OFFSET, reg);

        /* Wait up to 300 seconds in 50ms intervals */
        error = ETIMEDOUT;
        for (i = 0; i < 6000; i++) {
                /*
                 * Wait 50 msec. If this is the first time through, wait 256
                 * msec to satisfy Diag Reset timing requirements.
                 */
                if (first_wait_done) {
                        if (mtx_owned(&sc->mpr_mtx) && sleep_flag == CAN_SLEEP)
                                msleep(&sc->msleep_fake_chan, &sc->mpr_mtx, 0,
                                    "mprdiag", hz/20);
                        else if (sleep_flag == CAN_SLEEP)
                                pause("mprdiag", hz/20);
                        else
                                DELAY(50 * 1000);
                } else {
                        DELAY(256 * 1000);
                        first_wait_done = TRUE;
                }
                /*
                 * Check for the RESET_ADAPTER bit to be cleared first, then
                 * wait for the RESET state to be cleared, which takes a little
                 * longer.
                 */
                reg = mpr_regread(sc, MPI2_HOST_DIAGNOSTIC_OFFSET);
                if (reg & MPI2_DIAG_RESET_ADAPTER) {
                        continue;
                }
                reg = mpr_regread(sc, MPI2_DOORBELL_OFFSET);
                if ((reg & MPI2_IOC_STATE_MASK) != MPI2_IOC_STATE_RESET) {
                        error = 0;
                        break;
                }
        }
        if (error) {
                mpr_dprint(sc, MPR_INIT, "reset failed, error= %d, exit\n",
                    error);
                return (error);
        }

        mpr_regwrite(sc, MPI2_WRITE_SEQUENCE_OFFSET, 0x0);
        mpr_dprint(sc, MPR_INIT, "diag reset success, exit\n");

        return (0);
}

static int
mpr_message_unit_reset(struct mpr_softc *sc, int sleep_flag)
{
        int error;

        MPR_FUNCTRACE(sc);

        mpr_dprint(sc, MPR_INIT, "%s entered\n", __func__);

        error = 0;
        mpr_regwrite(sc, MPI2_DOORBELL_OFFSET,
            MPI2_FUNCTION_IOC_MESSAGE_UNIT_RESET <<
            MPI2_DOORBELL_FUNCTION_SHIFT);

        if (mpr_wait_db_ack(sc, 5, sleep_flag) != 0) {
                mpr_dprint(sc, MPR_INIT|MPR_FAULT,
                    "Doorbell handshake failed\n");
                error = ETIMEDOUT;
        }

        mpr_dprint(sc, MPR_INIT, "%s exit\n", __func__);
        return (error);
}

static int
mpr_transition_ready(struct mpr_softc *sc)
{
        uint32_t reg, state;
        int error, tries = 0;
        int sleep_flags;

        MPR_FUNCTRACE(sc);
        /* If we are in attach call, do not sleep */
        sleep_flags = (sc->mpr_flags & MPR_FLAGS_ATTACH_DONE)
            ? CAN_SLEEP : NO_SLEEP;

        error = 0;

        mpr_dprint(sc, MPR_INIT, "%s entered, sleep_flags= %d\n",
            __func__, sleep_flags);

        while (tries++ < 1200) {
                reg = mpr_regread(sc, MPI2_DOORBELL_OFFSET);
                mpr_dprint(sc, MPR_INIT, "  Doorbell= 0x%x\n", reg);

                /*
                 * Ensure the IOC is ready to talk.  If it's not, try
                 * resetting it.
                 */
                if (reg & MPI2_DOORBELL_USED) {
                        mpr_dprint(sc, MPR_INIT, "  Not ready, sending diag "
                            "reset\n");
                        mpr_diag_reset(sc, sleep_flags);
                        DELAY(50000);
                        continue;
                }

                /* Is the adapter owned by another peer? */
                if ((reg & MPI2_DOORBELL_WHO_INIT_MASK) ==
                    (MPI2_WHOINIT_PCI_PEER << MPI2_DOORBELL_WHO_INIT_SHIFT)) {
                        mpr_dprint(sc, MPR_INIT|MPR_FAULT, "IOC is under the "
                            "control of another peer host, aborting "
                            "initialization.\n");
                        error = ENXIO;
                        break;
                }
                
                state = reg & MPI2_IOC_STATE_MASK;
                if (state == MPI2_IOC_STATE_READY) {
                        /* Ready to go! */
                        error = 0;
                        break;
                } else if (state == MPI2_IOC_STATE_FAULT) {
                        mpr_dprint(sc, MPR_INIT|MPR_FAULT, "IOC in fault "
                            "state 0x%x, resetting\n",
                            state & MPI2_DOORBELL_FAULT_CODE_MASK);
                        mpr_diag_reset(sc, sleep_flags);
                } else if (state == MPI2_IOC_STATE_OPERATIONAL) {
                        /* Need to take ownership */
                        mpr_message_unit_reset(sc, sleep_flags);
                } else if (state == MPI2_IOC_STATE_RESET) {
                        /* Wait a bit, IOC might be in transition */
                        mpr_dprint(sc, MPR_INIT|MPR_FAULT,
                            "IOC in unexpected reset state\n");
                } else {
                        mpr_dprint(sc, MPR_INIT|MPR_FAULT,
                            "IOC in unknown state 0x%x\n", state);
                        error = EINVAL;
                        break;
                }
        
                /* Wait 50ms for things to settle down. */
                DELAY(50000);
        }

        if (error)
                mpr_dprint(sc, MPR_INIT|MPR_FAULT,
                    "Cannot transition IOC to ready\n");
        mpr_dprint(sc, MPR_INIT, "%s exit\n", __func__);
        return (error);
}

static int
mpr_transition_operational(struct mpr_softc *sc)
{
        uint32_t reg, state;
        int error;

        MPR_FUNCTRACE(sc);

        error = 0;
        reg = mpr_regread(sc, MPI2_DOORBELL_OFFSET);
        mpr_dprint(sc, MPR_INIT, "%s entered, Doorbell= 0x%x\n", __func__, reg);

        state = reg & MPI2_IOC_STATE_MASK;
        if (state != MPI2_IOC_STATE_READY) {
                mpr_dprint(sc, MPR_INIT, "IOC not ready\n");
                if ((error = mpr_transition_ready(sc)) != 0) {
                        mpr_dprint(sc, MPR_INIT|MPR_FAULT, 
                            "failed to transition ready, exit\n");
                        return (error);
                }
        }

        error = mpr_send_iocinit(sc);
        mpr_dprint(sc, MPR_INIT, "%s exit\n", __func__);

        return (error);
}

static void
mpr_resize_queues(struct mpr_softc *sc)
{
        u_int reqcr, prireqcr, maxio, sges_per_frame, chain_seg_size;

        /*
         * Size the queues. Since the reply queues always need one free
         * entry, we'll deduct one reply message here.  The LSI documents
         * suggest instead to add a count to the request queue, but I think
         * that it's better to deduct from reply queue.
         */
        prireqcr = MAX(1, sc->max_prireqframes);
        prireqcr = MIN(prireqcr, sc->facts->HighPriorityCredit);

        reqcr = MAX(2, sc->max_reqframes);
        reqcr = MIN(reqcr, sc->facts->RequestCredit);

        sc->num_reqs = prireqcr + reqcr;
        sc->num_prireqs = prireqcr;
        sc->num_replies = MIN(sc->max_replyframes + sc->max_evtframes,
            sc->facts->MaxReplyDescriptorPostQueueDepth) - 1;

        /* Store the request frame size in bytes rather than as 32bit words */
        sc->reqframesz = sc->facts->IOCRequestFrameSize * 4;

        /*
         * Gen3 and beyond uses the IOCMaxChainSegmentSize from IOC Facts to
         * get the size of a Chain Frame.  Previous versions use the size as a
         * Request Frame for the Chain Frame size.  If IOCMaxChainSegmentSize
         * is 0, use the default value.  The IOCMaxChainSegmentSize is the
         * number of 16-byte elelements that can fit in a Chain Frame, which is
         * the size of an IEEE Simple SGE.
         */
        if (sc->facts->MsgVersion >= MPI2_VERSION_02_05) {
                chain_seg_size = htole16(sc->facts->IOCMaxChainSegmentSize);
                if (chain_seg_size == 0)
                        chain_seg_size = MPR_DEFAULT_CHAIN_SEG_SIZE;
                sc->chain_frame_size = chain_seg_size *
                    MPR_MAX_CHAIN_ELEMENT_SIZE;
        } else {
                sc->chain_frame_size = sc->reqframesz;
        }

        /*
         * Max IO Size is Page Size * the following:
         * ((SGEs per frame - 1 for chain element) * Max Chain Depth)
         * + 1 for no chain needed in last frame
         *
         * If user suggests a Max IO size to use, use the smaller of the
         * user's value and the calculated value as long as the user's
         * value is larger than 0. The user's value is in pages.
         */
        sges_per_frame = sc->chain_frame_size/sizeof(MPI2_IEEE_SGE_SIMPLE64)-1;
        maxio = (sges_per_frame * sc->facts->MaxChainDepth + 1) * PAGE_SIZE;

        /*
         * If I/O size limitation requested then use it and pass up to CAM.
         * If not, use MAXPHYS as an optimization hint, but report HW limit.
         */
        if (sc->max_io_pages > 0) {
                maxio = min(maxio, sc->max_io_pages * PAGE_SIZE);
                sc->maxio = maxio;
        } else {
                sc->maxio = maxio;
                maxio = min(maxio, MAXPHYS);
        }

        sc->num_chains = (maxio / PAGE_SIZE + sges_per_frame - 2) /
            sges_per_frame * reqcr;
        if (sc->max_chains > 0 && sc->max_chains < sc->num_chains)
                sc->num_chains = sc->max_chains;

        /*
         * Figure out the number of MSIx-based queues.  If the firmware or
         * user has done something crazy and not allowed enough credit for
         * the queues to be useful then don't enable multi-queue.
         */
        if (sc->facts->MaxMSIxVectors < 2)
                sc->msi_msgs = 1;

        if (sc->msi_msgs > 1) {
                sc->msi_msgs = MIN(sc->msi_msgs, mp_ncpus);
                sc->msi_msgs = MIN(sc->msi_msgs, sc->facts->MaxMSIxVectors);
                if (sc->num_reqs / sc->msi_msgs < 2)
                        sc->msi_msgs = 1;
        }

        mpr_dprint(sc, MPR_INIT, "Sized queues to q=%d reqs=%d replies=%d\n",
            sc->msi_msgs, sc->num_reqs, sc->num_replies);
}

/*
 * This is called during attach and when re-initializing due to a Diag Reset.
 * IOC Facts is used to allocate many of the structures needed by the driver.
 * If called from attach, de-allocation is not required because the driver has
 * not allocated any structures yet, but if called from a Diag Reset, previously
 * allocated structures based on IOC Facts will need to be freed and re-
 * allocated bases on the latest IOC Facts.
 */
static int
mpr_iocfacts_allocate(struct mpr_softc *sc, uint8_t attaching)
{
        int error;
        Mpi2IOCFactsReply_t saved_facts;
        uint8_t saved_mode, reallocating;

        mpr_dprint(sc, MPR_INIT|MPR_TRACE, "%s entered\n", __func__);

        /* Save old IOC Facts and then only reallocate if Facts have changed */
        if (!attaching) {
                bcopy(sc->facts, &saved_facts, sizeof(MPI2_IOC_FACTS_REPLY));
        }

        /*
         * Get IOC Facts.  In all cases throughout this function, panic if doing
         * a re-initialization and only return the error if attaching so the OS
         * can handle it.
         */
        if ((error = mpr_get_iocfacts(sc, sc->facts)) != 0) {
                if (attaching) {
                        mpr_dprint(sc, MPR_INIT|MPR_FAULT, "Failed to get "
                            "IOC Facts with error %d, exit\n", error);
                        return (error);
                } else {
                        panic("%s failed to get IOC Facts with error %d\n",
                            __func__, error);
                }
        }

        MPR_DPRINT_PAGE(sc, MPR_XINFO, iocfacts, sc->facts);

        snprintf(sc->fw_version, sizeof(sc->fw_version), 
            "%02d.%02d.%02d.%02d", 
            sc->facts->FWVersion.Struct.Major,
            sc->facts->FWVersion.Struct.Minor,
            sc->facts->FWVersion.Struct.Unit,
            sc->facts->FWVersion.Struct.Dev);

        mpr_dprint(sc, MPR_INFO, "Firmware: %s, Driver: %s\n", sc->fw_version,
            MPR_DRIVER_VERSION);
        mpr_dprint(sc, MPR_INFO,
            "IOCCapabilities: %b\n", sc->facts->IOCCapabilities,
            "\20" "\3ScsiTaskFull" "\4DiagTrace" "\5SnapBuf" "\6ExtBuf"
            "\7EEDP" "\10BiDirTarg" "\11Multicast" "\14TransRetry" "\15IR"
            "\16EventReplay" "\17RaidAccel" "\20MSIXIndex" "\21HostDisc"
            "\22FastPath" "\23RDPQArray" "\24AtomicReqDesc" "\25PCIeSRIOV");

        /*
         * If the chip doesn't support event replay then a hard reset will be
         * required to trigger a full discovery.  Do the reset here then
         * retransition to Ready.  A hard reset might have already been done,
         * but it doesn't hurt to do it again.  Only do this if attaching, not
         * for a Diag Reset.
         */
        if (attaching && ((sc->facts->IOCCapabilities &
            MPI2_IOCFACTS_CAPABILITY_EVENT_REPLAY) == 0)) {
                mpr_dprint(sc, MPR_INIT, "No event replay, resetting\n");
                mpr_diag_reset(sc, NO_SLEEP);
                if ((error = mpr_transition_ready(sc)) != 0) {
                        mpr_dprint(sc, MPR_INIT|MPR_FAULT, "Failed to "
                            "transition to ready with error %d, exit\n",
                            error);
                        return (error);
                }
        }

        /*
         * Set flag if IR Firmware is loaded.  If the RAID Capability has
         * changed from the previous IOC Facts, log a warning, but only if
         * checking this after a Diag Reset and not during attach.
         */
        saved_mode = sc->ir_firmware;
        if (sc->facts->IOCCapabilities &
            MPI2_IOCFACTS_CAPABILITY_INTEGRATED_RAID)
                sc->ir_firmware = 1;
        if (!attaching) {
                if (sc->ir_firmware != saved_mode) {
                        mpr_dprint(sc, MPR_INIT|MPR_FAULT, "new IR/IT mode "
                            "in IOC Facts does not match previous mode\n");
                }
        }

        /* Only deallocate and reallocate if relevant IOC Facts have changed */
        reallocating = FALSE;
        sc->mpr_flags &= ~MPR_FLAGS_REALLOCATED;

        if ((!attaching) &&
            ((saved_facts.MsgVersion != sc->facts->MsgVersion) ||
            (saved_facts.HeaderVersion != sc->facts->HeaderVersion) ||
            (saved_facts.MaxChainDepth != sc->facts->MaxChainDepth) ||
            (saved_facts.RequestCredit != sc->facts->RequestCredit) ||
            (saved_facts.ProductID != sc->facts->ProductID) ||
            (saved_facts.IOCCapabilities != sc->facts->IOCCapabilities) ||
            (saved_facts.IOCRequestFrameSize !=
            sc->facts->IOCRequestFrameSize) ||
            (saved_facts.IOCMaxChainSegmentSize !=
            sc->facts->IOCMaxChainSegmentSize) ||
            (saved_facts.MaxTargets != sc->facts->MaxTargets) ||
            (saved_facts.MaxSasExpanders != sc->facts->MaxSasExpanders) ||
            (saved_facts.MaxEnclosures != sc->facts->MaxEnclosures) ||
            (saved_facts.HighPriorityCredit != sc->facts->HighPriorityCredit) ||
            (saved_facts.MaxReplyDescriptorPostQueueDepth !=
            sc->facts->MaxReplyDescriptorPostQueueDepth) ||
            (saved_facts.ReplyFrameSize != sc->facts->ReplyFrameSize) ||
            (saved_facts.MaxVolumes != sc->facts->MaxVolumes) ||
            (saved_facts.MaxPersistentEntries !=
            sc->facts->MaxPersistentEntries))) {
                reallocating = TRUE;

                /* Record that we reallocated everything */
                sc->mpr_flags |= MPR_FLAGS_REALLOCATED;
        }

        /*
         * Some things should be done if attaching or re-allocating after a Diag
         * Reset, but are not needed after a Diag Reset if the FW has not
         * changed.
         */
        if (attaching || reallocating) {
                /*
                 * Check if controller supports FW diag buffers and set flag to
                 * enable each type.
                 */
                if (sc->facts->IOCCapabilities &
                    MPI2_IOCFACTS_CAPABILITY_DIAG_TRACE_BUFFER)
                        sc->fw_diag_buffer_list[MPI2_DIAG_BUF_TYPE_TRACE].
                            enabled = TRUE;
                if (sc->facts->IOCCapabilities &
                    MPI2_IOCFACTS_CAPABILITY_SNAPSHOT_BUFFER)
                        sc->fw_diag_buffer_list[MPI2_DIAG_BUF_TYPE_SNAPSHOT].
                            enabled = TRUE;
                if (sc->facts->IOCCapabilities &
                    MPI2_IOCFACTS_CAPABILITY_EXTENDED_BUFFER)
                        sc->fw_diag_buffer_list[MPI2_DIAG_BUF_TYPE_EXTENDED].
                            enabled = TRUE;

                /*
                 * Set flags for some supported items.
                 */
                if (sc->facts->IOCCapabilities & MPI2_IOCFACTS_CAPABILITY_EEDP)
                        sc->eedp_enabled = TRUE;
                if (sc->facts->IOCCapabilities & MPI2_IOCFACTS_CAPABILITY_TLR)
                        sc->control_TLR = TRUE;
                if ((sc->facts->IOCCapabilities &
                    MPI26_IOCFACTS_CAPABILITY_ATOMIC_REQ) &&
                    (sc->mpr_flags & MPR_FLAGS_SEA_IOC))
                        sc->atomic_desc_capable = TRUE;

                mpr_resize_queues(sc);

                /*
                 * Initialize all Tail Queues
                 */
                TAILQ_INIT(&sc->req_list);
                TAILQ_INIT(&sc->high_priority_req_list);
                TAILQ_INIT(&sc->chain_list);
                TAILQ_INIT(&sc->prp_page_list);
                TAILQ_INIT(&sc->tm_list);
        }

        /*
         * If doing a Diag Reset and the FW is significantly different
         * (reallocating will be set above in IOC Facts comparison), then all
         * buffers based on the IOC Facts will need to be freed before they are
         * reallocated.
         */
        if (reallocating) {
                mpr_iocfacts_free(sc);
                mprsas_realloc_targets(sc, saved_facts.MaxTargets +
                    saved_facts.MaxVolumes);
        }

        /*
         * Any deallocation has been completed.  Now start reallocating
         * if needed.  Will only need to reallocate if attaching or if the new
         * IOC Facts are different from the previous IOC Facts after a Diag
         * Reset. Targets have already been allocated above if needed.
         */
        error = 0;
        while (attaching || reallocating) {
                if ((error = mpr_alloc_hw_queues(sc)) != 0)
                        break;
                if ((error = mpr_alloc_replies(sc)) != 0)
                        break;
                if ((error = mpr_alloc_requests(sc)) != 0)
                        break;
                if ((error = mpr_alloc_queues(sc)) != 0)
                        break;
                break;
        }
        if (error) {
                mpr_dprint(sc, MPR_INIT|MPR_ERROR,
                    "Failed to alloc queues with error %d\n", error);
                mpr_free(sc);
                return (error);
        }

        /* Always initialize the queues */
        bzero(sc->free_queue, sc->fqdepth * 4);
        mpr_init_queues(sc);

        /*
         * Always get the chip out of the reset state, but only panic if not
         * attaching.  If attaching and there is an error, that is handled by
         * the OS.
         */
        error = mpr_transition_operational(sc);
        if (error != 0) {
                mpr_dprint(sc, MPR_INIT|MPR_FAULT, "Failed to "
                    "transition to operational with error %d\n", error);
                mpr_free(sc);
                return (error);
        }

        /*
         * Finish the queue initialization.
         * These are set here instead of in mpr_init_queues() because the
         * IOC resets these values during the state transition in
         * mpr_transition_operational().  The free index is set to 1
         * because the corresponding index in the IOC is set to 0, and the
         * IOC treats the queues as full if both are set to the same value.
         * Hence the reason that the queue can't hold all of the possible
         * replies.
         */
        sc->replypostindex = 0;
        mpr_regwrite(sc, MPI2_REPLY_FREE_HOST_INDEX_OFFSET, sc->replyfreeindex);
        mpr_regwrite(sc, MPI2_REPLY_POST_HOST_INDEX_OFFSET, 0);

        /*
         * Attach the subsystems so they can prepare their event masks.
         * XXX Should be dynamic so that IM/IR and user modules can attach
         */
        error = 0;
        while (attaching) {
                mpr_dprint(sc, MPR_INIT, "Attaching subsystems\n");
                if ((error = mpr_attach_log(sc)) != 0)
                        break;
                if ((error = mpr_attach_sas(sc)) != 0)
                        break;
                if ((error = mpr_attach_user(sc)) != 0)
                        break;
                break;
        }
        if (error) {
                mpr_dprint(sc, MPR_INIT|MPR_ERROR,
                    "Failed to attach all subsystems: error %d\n", error);
                mpr_free(sc);
                return (error);
        }

        /*
         * XXX If the number of MSI-X vectors changes during re-init, this
         * won't see it and adjust.
         */
        if (attaching && (error = mpr_pci_setup_interrupts(sc)) != 0) {
                mpr_dprint(sc, MPR_INIT|MPR_ERROR,
                    "Failed to setup interrupts\n");
                mpr_free(sc);
                return (error);
        }

        return (error);
}

/*
 * This is called if memory is being free (during detach for example) and when
 * buffers need to be reallocated due to a Diag Reset.
 */
static void
mpr_iocfacts_free(struct mpr_softc *sc)
{
        struct mpr_command *cm;
        int i;

        mpr_dprint(sc, MPR_TRACE, "%s\n", __func__);

        if (sc->free_busaddr != 0)
                bus_dmamap_unload(sc->queues_dmat, sc->queues_map);
        if (sc->free_queue != NULL)
                bus_dmamem_free(sc->queues_dmat, sc->free_queue,
                    sc->queues_map);
        if (sc->queues_dmat != NULL)
                bus_dma_tag_destroy(sc->queues_dmat);

        if (sc->chain_frames != NULL) {
                bus_dmamap_unload(sc->chain_dmat, sc->chain_map);
                bus_dmamem_free(sc->chain_dmat, sc->chain_frames,
                    sc->chain_map);
        }
        if (sc->chain_dmat != NULL)
                bus_dma_tag_destroy(sc->chain_dmat);

        if (sc->sense_busaddr != 0)
                bus_dmamap_unload(sc->sense_dmat, sc->sense_map);
        if (sc->sense_frames != NULL)
                bus_dmamem_free(sc->sense_dmat, sc->sense_frames,
                    sc->sense_map);
        if (sc->sense_dmat != NULL)
                bus_dma_tag_destroy(sc->sense_dmat);

        if (sc->prp_page_busaddr != 0)
                bus_dmamap_unload(sc->prp_page_dmat, sc->prp_page_map);
        if (sc->prp_pages != NULL)
                bus_dmamem_free(sc->prp_page_dmat, sc->prp_pages,
                    sc->prp_page_map);
        if (sc->prp_page_dmat != NULL)
                bus_dma_tag_destroy(sc->prp_page_dmat);

        if (sc->reply_busaddr != 0)
                bus_dmamap_unload(sc->reply_dmat, sc->reply_map);
        if (sc->reply_frames != NULL)
                bus_dmamem_free(sc->reply_dmat, sc->reply_frames,
                    sc->reply_map);
        if (sc->reply_dmat != NULL)
                bus_dma_tag_destroy(sc->reply_dmat);

        if (sc->req_busaddr != 0)
                bus_dmamap_unload(sc->req_dmat, sc->req_map);
        if (sc->req_frames != NULL)
                bus_dmamem_free(sc->req_dmat, sc->req_frames, sc->req_map);
        if (sc->req_dmat != NULL)
                bus_dma_tag_destroy(sc->req_dmat);

        if (sc->chains != NULL)
                free(sc->chains, M_MPR);
        if (sc->prps != NULL)
                free(sc->prps, M_MPR);
        if (sc->commands != NULL) {
                for (i = 1; i < sc->num_reqs; i++) {
                        cm = &sc->commands[i];
                        bus_dmamap_destroy(sc->buffer_dmat, cm->cm_dmamap);
                }
                free(sc->commands, M_MPR);
        }
        if (sc->buffer_dmat != NULL)
                bus_dma_tag_destroy(sc->buffer_dmat);

        mpr_pci_free_interrupts(sc);
        free(sc->queues, M_MPR);
        sc->queues = NULL;
}

/* 
 * The terms diag reset and hard reset are used interchangeably in the MPI
 * docs to mean resetting the controller chip.  In this code diag reset
 * cleans everything up, and the hard reset function just sends the reset
 * sequence to the chip.  This should probably be refactored so that every
 * subsystem gets a reset notification of some sort, and can clean up
 * appropriately.
 */
int
mpr_reinit(struct mpr_softc *sc)
{
        int error;
        struct mprsas_softc *sassc;

        sassc = sc->sassc;

        MPR_FUNCTRACE(sc);

        mtx_assert(&sc->mpr_mtx, MA_OWNED);

        mpr_dprint(sc, MPR_INIT|MPR_INFO, "Reinitializing controller\n");
        if (sc->mpr_flags & MPR_FLAGS_DIAGRESET) {
                mpr_dprint(sc, MPR_INIT, "Reset already in progress\n");
                return 0;
        }

        /*
         * Make sure the completion callbacks can recognize they're getting
         * a NULL cm_reply due to a reset.
         */
        sc->mpr_flags |= MPR_FLAGS_DIAGRESET;

        /*
         * Mask interrupts here.
         */
        mpr_dprint(sc, MPR_INIT, "Masking interrupts and resetting\n");
        mpr_mask_intr(sc);

        error = mpr_diag_reset(sc, CAN_SLEEP);
        if (error != 0) {
                panic("%s hard reset failed with error %d\n", __func__, error);
        }

        /* Restore the PCI state, including the MSI-X registers */
        mpr_pci_restore(sc);

        /* Give the I/O subsystem special priority to get itself prepared */
        mprsas_handle_reinit(sc);

        /*
         * Get IOC Facts and allocate all structures based on this information.
         * The attach function will also call mpr_iocfacts_allocate at startup.
         * If relevant values have changed in IOC Facts, this function will free
         * all of the memory based on IOC Facts and reallocate that memory.
         */
        if ((error = mpr_iocfacts_allocate(sc, FALSE)) != 0) {
                panic("%s IOC Facts based allocation failed with error %d\n",
                    __func__, error);
        }

        /*
         * Mapping structures will be re-allocated after getting IOC Page8, so
         * free these structures here.
         */
        mpr_mapping_exit(sc);

        /*
         * The static page function currently read is IOC Page8.  Others can be
         * added in future.  It's possible that the values in IOC Page8 have
         * changed after a Diag Reset due to user modification, so always read
         * these.  Interrupts are masked, so unmask them before getting config
         * pages.
         */
        mpr_unmask_intr(sc);
        sc->mpr_flags &= ~MPR_FLAGS_DIAGRESET;
        mpr_base_static_config_pages(sc);

        /*
         * Some mapping info is based in IOC Page8 data, so re-initialize the
         * mapping tables.
         */
        mpr_mapping_initialize(sc);

        /*
         * Restart will reload the event masks clobbered by the reset, and
         * then enable the port.
         */
        mpr_reregister_events(sc);

        /* the end of discovery will release the simq, so we're done. */
        mpr_dprint(sc, MPR_INIT|MPR_XINFO, "Finished sc %p post %u free %u\n", 
            sc, sc->replypostindex, sc->replyfreeindex);
        mprsas_release_simq_reinit(sassc);
        mpr_dprint(sc, MPR_INIT, "%s exit error= %d\n", __func__, error);

        return 0;
}

/* Wait for the chip to ACK a word that we've put into its FIFO 
 * Wait for <timeout> seconds. In single loop wait for busy loop
 * for 500 microseconds.
 * Total is [ 0.5 * (2000 * <timeout>) ] in miliseconds.
 * */
static int
mpr_wait_db_ack(struct mpr_softc *sc, int timeout, int sleep_flag)
{
        u32 cntdn, count;
        u32 int_status;
        u32 doorbell;

        count = 0;
        cntdn = (sleep_flag == CAN_SLEEP) ? 1000*timeout : 2000*timeout;
        do {
                int_status = mpr_regread(sc, MPI2_HOST_INTERRUPT_STATUS_OFFSET);
                if (!(int_status & MPI2_HIS_SYS2IOC_DB_STATUS)) {
                        mpr_dprint(sc, MPR_TRACE, "%s: successful count(%d), "
                            "timeout(%d)\n", __func__, count, timeout);
                        return 0;
                } else if (int_status & MPI2_HIS_IOC2SYS_DB_STATUS) {
                        doorbell = mpr_regread(sc, MPI2_DOORBELL_OFFSET);
                        if ((doorbell & MPI2_IOC_STATE_MASK) ==
                            MPI2_IOC_STATE_FAULT) {
                                mpr_dprint(sc, MPR_FAULT,
                                    "fault_state(0x%04x)!\n", doorbell);
                                return (EFAULT);
                        }
                } else if (int_status == 0xFFFFFFFF)
                        goto out;
                        
                /*
                 * If it can sleep, sleep for 1 milisecond, else busy loop for
                 * 0.5 milisecond
                 */
                if (mtx_owned(&sc->mpr_mtx) && sleep_flag == CAN_SLEEP)
                        msleep(&sc->msleep_fake_chan, &sc->mpr_mtx, 0, "mprdba",
                            hz/1000);
                else if (sleep_flag == CAN_SLEEP)
                        pause("mprdba", hz/1000);
                else
                        DELAY(500);
                count++;
        } while (--cntdn);

out:
        mpr_dprint(sc, MPR_FAULT, "%s: failed due to timeout count(%d), "
                "int_status(%x)!\n", __func__, count, int_status);
        return (ETIMEDOUT);
}

/* Wait for the chip to signal that the next word in its FIFO can be fetched */
static int
mpr_wait_db_int(struct mpr_softc *sc)
{
        int retry;

        for (retry = 0; retry < MPR_DB_MAX_WAIT; retry++) {
                if ((mpr_regread(sc, MPI2_HOST_INTERRUPT_STATUS_OFFSET) &
                    MPI2_HIS_IOC2SYS_DB_STATUS) != 0)
                        return (0);
                DELAY(2000);
        }
        return (ETIMEDOUT);
}

/* Step through the synchronous command state machine, i.e. "Doorbell mode" */
static int
mpr_request_sync(struct mpr_softc *sc, void *req, MPI2_DEFAULT_REPLY *reply,
    int req_sz, int reply_sz, int timeout)
{
        uint32_t *data32;
        uint16_t *data16;
        int i, count, ioc_sz, residual;
        int sleep_flags = CAN_SLEEP;
        
#if __FreeBSD_version >= 1000029
        if (curthread->td_no_sleeping)
#else //__FreeBSD_version < 1000029
        if (curthread->td_pflags & TDP_NOSLEEPING)
#endif //__FreeBSD_version >= 1000029
                sleep_flags = NO_SLEEP;

        /* Step 1 */
        mpr_regwrite(sc, MPI2_HOST_INTERRUPT_STATUS_OFFSET, 0x0);

        /* Step 2 */
        if (mpr_regread(sc, MPI2_DOORBELL_OFFSET) & MPI2_DOORBELL_USED)
                return (EBUSY);

        /* Step 3
         * Announce that a message is coming through the doorbell.  Messages
         * are pushed at 32bit words, so round up if needed.
         */
        count = (req_sz + 3) / 4;
        mpr_regwrite(sc, MPI2_DOORBELL_OFFSET,
            (MPI2_FUNCTION_HANDSHAKE << MPI2_DOORBELL_FUNCTION_SHIFT) |
            (count << MPI2_DOORBELL_ADD_DWORDS_SHIFT));

        /* Step 4 */
        if (mpr_wait_db_int(sc) ||
            (mpr_regread(sc, MPI2_DOORBELL_OFFSET) & MPI2_DOORBELL_USED) == 0) {
                mpr_dprint(sc, MPR_FAULT, "Doorbell failed to activate\n");
                return (ENXIO);
        }
        mpr_regwrite(sc, MPI2_HOST_INTERRUPT_STATUS_OFFSET, 0x0);
        if (mpr_wait_db_ack(sc, 5, sleep_flags) != 0) {
                mpr_dprint(sc, MPR_FAULT, "Doorbell handshake failed\n");
                return (ENXIO);
        }

        /* Step 5 */
        /* Clock out the message data synchronously in 32-bit dwords*/
        data32 = (uint32_t *)req;
        for (i = 0; i < count; i++) {
                mpr_regwrite(sc, MPI2_DOORBELL_OFFSET, htole32(data32[i]));
                if (mpr_wait_db_ack(sc, 5, sleep_flags) != 0) {
                        mpr_dprint(sc, MPR_FAULT,
                            "Timeout while writing doorbell\n");
                        return (ENXIO);
                }
        }

        /* Step 6 */
        /* Clock in the reply in 16-bit words.  The total length of the
         * message is always in the 4th byte, so clock out the first 2 words
         * manually, then loop the rest.
         */
        data16 = (uint16_t *)reply;
        if (mpr_wait_db_int(sc) != 0) {
                mpr_dprint(sc, MPR_FAULT, "Timeout reading doorbell 0\n");
                return (ENXIO);
        }
        data16[0] =
            mpr_regread(sc, MPI2_DOORBELL_OFFSET) & MPI2_DOORBELL_DATA_MASK;
        mpr_regwrite(sc, MPI2_HOST_INTERRUPT_STATUS_OFFSET, 0x0);
        if (mpr_wait_db_int(sc) != 0) {
                mpr_dprint(sc, MPR_FAULT, "Timeout reading doorbell 1\n");
                return (ENXIO);
        }
        data16[1] =
            mpr_regread(sc, MPI2_DOORBELL_OFFSET) & MPI2_DOORBELL_DATA_MASK;
        mpr_regwrite(sc, MPI2_HOST_INTERRUPT_STATUS_OFFSET, 0x0);

        /* Number of 32bit words in the message */
        ioc_sz = reply->MsgLength;

        /*
         * Figure out how many 16bit words to clock in without overrunning.
         * The precision loss with dividing reply_sz can safely be
         * ignored because the messages can only be multiples of 32bits.
         */
        residual = 0;
        count = MIN((reply_sz / 4), ioc_sz) * 2;
        if (count < ioc_sz * 2) {
                residual = ioc_sz * 2 - count;
                mpr_dprint(sc, MPR_ERROR, "Driver error, throwing away %d "
                    "residual message words\n", residual);
        }

        for (i = 2; i < count; i++) {
                if (mpr_wait_db_int(sc) != 0) {
                        mpr_dprint(sc, MPR_FAULT,
                            "Timeout reading doorbell %d\n", i);
                        return (ENXIO);
                }
                data16[i] = mpr_regread(sc, MPI2_DOORBELL_OFFSET) &
                    MPI2_DOORBELL_DATA_MASK;
                mpr_regwrite(sc, MPI2_HOST_INTERRUPT_STATUS_OFFSET, 0x0);
        }

        /*
         * Pull out residual words that won't fit into the provided buffer.
         * This keeps the chip from hanging due to a driver programming
         * error.
         */
        while (residual--) {
                if (mpr_wait_db_int(sc) != 0) {
                        mpr_dprint(sc, MPR_FAULT, "Timeout reading doorbell\n");
                        return (ENXIO);
                }
                (void)mpr_regread(sc, MPI2_DOORBELL_OFFSET);
                mpr_regwrite(sc, MPI2_HOST_INTERRUPT_STATUS_OFFSET, 0x0);
        }

        /* Step 7 */
        if (mpr_wait_db_int(sc) != 0) {
                mpr_dprint(sc, MPR_FAULT, "Timeout waiting to exit doorbell\n");
                return (ENXIO);
        }
        if (mpr_regread(sc, MPI2_DOORBELL_OFFSET) & MPI2_DOORBELL_USED)
                mpr_dprint(sc, MPR_FAULT, "Warning, doorbell still active\n");
        mpr_regwrite(sc, MPI2_HOST_INTERRUPT_STATUS_OFFSET, 0x0);

        return (0);
}

static void
mpr_enqueue_request(struct mpr_softc *sc, struct mpr_command *cm)
{
        request_descriptor rd;

        MPR_FUNCTRACE(sc);
        mpr_dprint(sc, MPR_TRACE, "SMID %u cm %p ccb %p\n",
            cm->cm_desc.Default.SMID, cm, cm->cm_ccb);

        if (sc->mpr_flags & MPR_FLAGS_ATTACH_DONE && !(sc->mpr_flags &
            MPR_FLAGS_SHUTDOWN))
                mtx_assert(&sc->mpr_mtx, MA_OWNED);

        if (++sc->io_cmds_active > sc->io_cmds_highwater)
                sc->io_cmds_highwater++;

        KASSERT(cm->cm_state == MPR_CM_STATE_BUSY, ("command not busy\n"));
        cm->cm_state = MPR_CM_STATE_INQUEUE;

        if (sc->atomic_desc_capable) {
                rd.u.low = cm->cm_desc.Words.Low;
                mpr_regwrite(sc, MPI26_ATOMIC_REQUEST_DESCRIPTOR_POST_OFFSET,
                    rd.u.low);
        } else {
                rd.u.low = cm->cm_desc.Words.Low;
                rd.u.high = cm->cm_desc.Words.High;
                rd.word = htole64(rd.word);
                mpr_regwrite(sc, MPI2_REQUEST_DESCRIPTOR_POST_LOW_OFFSET,
                    rd.u.low);
                mpr_regwrite(sc, MPI2_REQUEST_DESCRIPTOR_POST_HIGH_OFFSET,
                    rd.u.high);
        }
}

/*
 * Just the FACTS, ma'am.
 */
static int
mpr_get_iocfacts(struct mpr_softc *sc, MPI2_IOC_FACTS_REPLY *facts)
{
        MPI2_DEFAULT_REPLY *reply;
        MPI2_IOC_FACTS_REQUEST request;
        int error, req_sz, reply_sz;

        MPR_FUNCTRACE(sc);
        mpr_dprint(sc, MPR_INIT, "%s entered\n", __func__);

        req_sz = sizeof(MPI2_IOC_FACTS_REQUEST);
        reply_sz = sizeof(MPI2_IOC_FACTS_REPLY);
        reply = (MPI2_DEFAULT_REPLY *)facts;

        bzero(&request, req_sz);
        request.Function = MPI2_FUNCTION_IOC_FACTS;
        error = mpr_request_sync(sc, &request, reply, req_sz, reply_sz, 5);

        mpr_dprint(sc, MPR_INIT, "%s exit, error= %d\n", __func__, error);
        return (error);
}

static int
mpr_send_iocinit(struct mpr_softc *sc)
{
        MPI2_IOC_INIT_REQUEST   init;
        MPI2_DEFAULT_REPLY      reply;
        int req_sz, reply_sz, error;
        struct timeval now;
        uint64_t time_in_msec;

        MPR_FUNCTRACE(sc);
        mpr_dprint(sc, MPR_INIT, "%s entered\n", __func__);

        /* Do a quick sanity check on proper initialization */
        if ((sc->pqdepth == 0) || (sc->fqdepth == 0) || (sc->reqframesz == 0)
            || (sc->replyframesz == 0)) {
                mpr_dprint(sc, MPR_INIT|MPR_ERROR,
                    "Driver not fully initialized for IOCInit\n");
                return (EINVAL);
        }

        req_sz = sizeof(MPI2_IOC_INIT_REQUEST);
        reply_sz = sizeof(MPI2_IOC_INIT_REPLY);
        bzero(&init, req_sz);
        bzero(&reply, reply_sz);

        /*
         * Fill in the init block.  Note that most addresses are
         * deliberately in the lower 32bits of memory.  This is a micro-
         * optimzation for PCI/PCIX, though it's not clear if it helps PCIe.
         */
        init.Function = MPI2_FUNCTION_IOC_INIT;
        init.WhoInit = MPI2_WHOINIT_HOST_DRIVER;
        init.MsgVersion = htole16(MPI2_VERSION);
        init.HeaderVersion = htole16(MPI2_HEADER_VERSION);
        init.SystemRequestFrameSize = htole16((uint16_t)(sc->reqframesz / 4));
        init.ReplyDescriptorPostQueueDepth = htole16(sc->pqdepth);
        init.ReplyFreeQueueDepth = htole16(sc->fqdepth);
        init.SenseBufferAddressHigh = 0;
        init.SystemReplyAddressHigh = 0;
        init.SystemRequestFrameBaseAddress.High = 0;
        init.SystemRequestFrameBaseAddress.Low =
            htole32((uint32_t)sc->req_busaddr);
        init.ReplyDescriptorPostQueueAddress.High = 0;
        init.ReplyDescriptorPostQueueAddress.Low =
            htole32((uint32_t)sc->post_busaddr);
        init.ReplyFreeQueueAddress.High = 0;
        init.ReplyFreeQueueAddress.Low = htole32((uint32_t)sc->free_busaddr);
        getmicrotime(&now);
        time_in_msec = (now.tv_sec * 1000 + now.tv_usec/1000);
        init.TimeStamp.High = htole32((time_in_msec >> 32) & 0xFFFFFFFF);
        init.TimeStamp.Low = htole32(time_in_msec & 0xFFFFFFFF);
        init.HostPageSize = HOST_PAGE_SIZE_4K;

        error = mpr_request_sync(sc, &init, &reply, req_sz, reply_sz, 5);
        if ((reply.IOCStatus & MPI2_IOCSTATUS_MASK) != MPI2_IOCSTATUS_SUCCESS)
                error = ENXIO;

        mpr_dprint(sc, MPR_INIT, "IOCInit status= 0x%x\n", reply.IOCStatus);
        mpr_dprint(sc, MPR_INIT, "%s exit\n", __func__);
        return (error);
}

void
mpr_memaddr_cb(void *arg, bus_dma_segment_t *segs, int nsegs, int error)
{
        bus_addr_t *addr;

        addr = arg;
        *addr = segs[0].ds_addr;
}

void
mpr_memaddr_wait_cb(void *arg, bus_dma_segment_t *segs, int nsegs, int error)
{
        struct mpr_busdma_context *ctx;
        int need_unload, need_free;

        ctx = (struct mpr_busdma_context *)arg;
        need_unload = 0;
        need_free = 0;

        mpr_lock(ctx->softc);
        ctx->error = error;
        ctx->completed = 1;
        if ((error == 0) && (ctx->abandoned == 0)) {
                *ctx->addr = segs[0].ds_addr;
        } else {
                if (nsegs != 0)
                        need_unload = 1;
                if (ctx->abandoned != 0)
                        need_free = 1;
        }
        if (need_free == 0)
                wakeup(ctx);

        mpr_unlock(ctx->softc);

        if (need_unload != 0) {
                bus_dmamap_unload(ctx->buffer_dmat,
                                  ctx->buffer_dmamap);
                *ctx->addr = 0;
        }

        if (need_free != 0)
                free(ctx, M_MPR);
}

static int
mpr_alloc_queues(struct mpr_softc *sc)
{
        struct mpr_queue *q;
        int nq, i;

        nq = sc->msi_msgs;
        mpr_dprint(sc, MPR_INIT|MPR_XINFO, "Allocating %d I/O queues\n", nq);

        sc->queues = malloc(sizeof(struct mpr_queue) * nq, M_MPR,
             M_NOWAIT|M_ZERO);
        if (sc->queues == NULL)
                return (ENOMEM);

        for (i = 0; i < nq; i++) {
                q = &sc->queues[i];
                mpr_dprint(sc, MPR_INIT, "Configuring queue %d %p\n", i, q);
                q->sc = sc;
                q->qnum = i;
        }
        return (0);
}

static int
mpr_alloc_hw_queues(struct mpr_softc *sc)
{
        bus_addr_t queues_busaddr;
        uint8_t *queues;
        int qsize, fqsize, pqsize;

        /*
         * The reply free queue contains 4 byte entries in multiples of 16 and
         * aligned on a 16 byte boundary. There must always be an unused entry.
         * This queue supplies fresh reply frames for the firmware to use.
         *
         * The reply descriptor post queue contains 8 byte entries in
         * multiples of 16 and aligned on a 16 byte boundary.  This queue
         * contains filled-in reply frames sent from the firmware to the host.
         *
         * These two queues are allocated together for simplicity.
         */
        sc->fqdepth = roundup2(sc->num_replies + 1, 16);
        sc->pqdepth = roundup2(sc->num_replies + 1, 16);
        fqsize= sc->fqdepth * 4;
        pqsize = sc->pqdepth * 8;
        qsize = fqsize + pqsize;

        if (bus_dma_tag_create( sc->mpr_parent_dmat,    /* parent */
                                16, 0,                  /* algnmnt, boundary */
                                BUS_SPACE_MAXADDR_32BIT,/* lowaddr */
                                BUS_SPACE_MAXADDR,      /* highaddr */
                                NULL, NULL,             /* filter, filterarg */
                                qsize,                  /* maxsize */
                                1,                      /* nsegments */
                                qsize,                  /* maxsegsize */
                                0,                      /* flags */
                                NULL, NULL,             /* lockfunc, lockarg */
                                &sc->queues_dmat)) {
                mpr_dprint(sc, MPR_ERROR, "Cannot allocate queues DMA tag\n");
                return (ENOMEM);
        }
        if (bus_dmamem_alloc(sc->queues_dmat, (void **)&queues, BUS_DMA_NOWAIT,
            &sc->queues_map)) {
                mpr_dprint(sc, MPR_ERROR, "Cannot allocate queues memory\n");
                return (ENOMEM);
        }
        bzero(queues, qsize);
        bus_dmamap_load(sc->queues_dmat, sc->queues_map, queues, qsize,
            mpr_memaddr_cb, &queues_busaddr, 0);

        sc->free_queue = (uint32_t *)queues;
        sc->free_busaddr = queues_busaddr;
        sc->post_queue = (MPI2_REPLY_DESCRIPTORS_UNION *)(queues + fqsize);
        sc->post_busaddr = queues_busaddr + fqsize;
        mpr_dprint(sc, MPR_INIT, "free queue busaddr= %#016jx size= %d\n",
            (uintmax_t)sc->free_busaddr, fqsize);
        mpr_dprint(sc, MPR_INIT, "reply queue busaddr= %#016jx size= %d\n",
            (uintmax_t)sc->post_busaddr, pqsize);

        return (0);
}

static int
mpr_alloc_replies(struct mpr_softc *sc)
{
        int rsize, num_replies;

        /* Store the reply frame size in bytes rather than as 32bit words */
        sc->replyframesz = sc->facts->ReplyFrameSize * 4;

        /*
         * sc->num_replies should be one less than sc->fqdepth.  We need to
         * allocate space for sc->fqdepth replies, but only sc->num_replies
         * replies can be used at once.
         */
        num_replies = max(sc->fqdepth, sc->num_replies);

        rsize = sc->replyframesz * num_replies; 
        if (bus_dma_tag_create( sc->mpr_parent_dmat,    /* parent */
                                4, 0,                   /* algnmnt, boundary */
                                BUS_SPACE_MAXADDR_32BIT,/* lowaddr */
                                BUS_SPACE_MAXADDR,      /* highaddr */
                                NULL, NULL,             /* filter, filterarg */
                                rsize,                  /* maxsize */
                                1,                      /* nsegments */
                                rsize,                  /* maxsegsize */
                                0,                      /* flags */
                                NULL, NULL,             /* lockfunc, lockarg */
                                &sc->reply_dmat)) {
                mpr_dprint(sc, MPR_ERROR, "Cannot allocate replies DMA tag\n");
                return (ENOMEM);
        }
        if (bus_dmamem_alloc(sc->reply_dmat, (void **)&sc->reply_frames,
            BUS_DMA_NOWAIT, &sc->reply_map)) {
                mpr_dprint(sc, MPR_ERROR, "Cannot allocate replies memory\n");
                return (ENOMEM);
        }
        bzero(sc->reply_frames, rsize);
        bus_dmamap_load(sc->reply_dmat, sc->reply_map, sc->reply_frames, rsize,
            mpr_memaddr_cb, &sc->reply_busaddr, 0);
        mpr_dprint(sc, MPR_INIT, "reply frames busaddr= %#016jx size= %d\n",
            (uintmax_t)sc->reply_busaddr, rsize);

        return (0);
}

static void
mpr_load_chains_cb(void *arg, bus_dma_segment_t *segs, int nsegs, int error)
{
        struct mpr_softc *sc = arg;
        struct mpr_chain *chain;
        bus_size_t bo;
        int i, o, s;

        if (error != 0)
                return;

        for (i = 0, o = 0, s = 0; s < nsegs; s++) {
                for (bo = 0; bo + sc->chain_frame_size <= segs[s].ds_len;
                    bo += sc->chain_frame_size) {
                        chain = &sc->chains[i++];
                        chain->chain =(MPI2_SGE_IO_UNION *)(sc->chain_frames+o);
                        chain->chain_busaddr = segs[s].ds_addr + bo;
                        o += sc->chain_frame_size;
                        mpr_free_chain(sc, chain);
                }
                if (bo != segs[s].ds_len)
                        o += segs[s].ds_len - bo;
        }
        sc->chain_free_lowwater = i;
}

static int
mpr_alloc_requests(struct mpr_softc *sc)
{
        struct mpr_command *cm;
        int i, rsize, nsegs;

        rsize = sc->reqframesz * sc->num_reqs;
        if (bus_dma_tag_create( sc->mpr_parent_dmat,    /* parent */
                                16, 0,                  /* algnmnt, boundary */
                                BUS_SPACE_MAXADDR_32BIT,/* lowaddr */
                                BUS_SPACE_MAXADDR,      /* highaddr */
                                NULL, NULL,             /* filter, filterarg */
                                rsize,                  /* maxsize */
                                1,                      /* nsegments */
                                rsize,                  /* maxsegsize */
                                0,                      /* flags */
                                NULL, NULL,             /* lockfunc, lockarg */
                                &sc->req_dmat)) {
                mpr_dprint(sc, MPR_ERROR, "Cannot allocate request DMA tag\n");
                return (ENOMEM);
        }
        if (bus_dmamem_alloc(sc->req_dmat, (void **)&sc->req_frames,
            BUS_DMA_NOWAIT, &sc->req_map)) {
                mpr_dprint(sc, MPR_ERROR, "Cannot allocate request memory\n");
                return (ENOMEM);
        }
        bzero(sc->req_frames, rsize);
        bus_dmamap_load(sc->req_dmat, sc->req_map, sc->req_frames, rsize,
            mpr_memaddr_cb, &sc->req_busaddr, 0);
        mpr_dprint(sc, MPR_INIT, "request frames busaddr= %#016jx size= %d\n",
            (uintmax_t)sc->req_busaddr, rsize);

        sc->chains = malloc(sizeof(struct mpr_chain) * sc->num_chains, M_MPR,
            M_NOWAIT | M_ZERO);
        if (!sc->chains) {
                mpr_dprint(sc, MPR_ERROR, "Cannot allocate chain memory\n");
                return (ENOMEM);
        }
        rsize = sc->chain_frame_size * sc->num_chains;
        if (bus_dma_tag_create( sc->mpr_parent_dmat,    /* parent */
                                16, 0,                  /* algnmnt, boundary */
                                BUS_SPACE_MAXADDR,      /* lowaddr */
                                BUS_SPACE_MAXADDR,      /* highaddr */
                                NULL, NULL,             /* filter, filterarg */
                                rsize,                  /* maxsize */
                                howmany(rsize, PAGE_SIZE), /* nsegments */
                                rsize,                  /* maxsegsize */
                                0,                      /* flags */
                                NULL, NULL,             /* lockfunc, lockarg */
                                &sc->chain_dmat)) {
                mpr_dprint(sc, MPR_ERROR, "Cannot allocate chain DMA tag\n");
                return (ENOMEM);
        }
        if (bus_dmamem_alloc(sc->chain_dmat, (void **)&sc->chain_frames,
            BUS_DMA_NOWAIT | BUS_DMA_ZERO, &sc->chain_map)) {
                mpr_dprint(sc, MPR_ERROR, "Cannot allocate chain memory\n");
                return (ENOMEM);
        }
        if (bus_dmamap_load(sc->chain_dmat, sc->chain_map, sc->chain_frames,
            rsize, mpr_load_chains_cb, sc, BUS_DMA_NOWAIT)) {
                mpr_dprint(sc, MPR_ERROR, "Cannot load chain memory\n");
                bus_dmamem_free(sc->chain_dmat, sc->chain_frames,
                    sc->chain_map);
                return (ENOMEM);
        }

        rsize = MPR_SENSE_LEN * sc->num_reqs;
        if (bus_dma_tag_create( sc->mpr_parent_dmat,    /* parent */
                                1, 0,                   /* algnmnt, boundary */
                                BUS_SPACE_MAXADDR_32BIT,/* lowaddr */
                                BUS_SPACE_MAXADDR,      /* highaddr */
                                NULL, NULL,             /* filter, filterarg */
                                rsize,                  /* maxsize */
                                1,                      /* nsegments */
                                rsize,                  /* maxsegsize */
                                0,                      /* flags */
                                NULL, NULL,             /* lockfunc, lockarg */
                                &sc->sense_dmat)) {
                mpr_dprint(sc, MPR_ERROR, "Cannot allocate sense DMA tag\n");
                return (ENOMEM);
        }
        if (bus_dmamem_alloc(sc->sense_dmat, (void **)&sc->sense_frames,
            BUS_DMA_NOWAIT, &sc->sense_map)) {
                mpr_dprint(sc, MPR_ERROR, "Cannot allocate sense memory\n");
                return (ENOMEM);
        }
        bzero(sc->sense_frames, rsize);
        bus_dmamap_load(sc->sense_dmat, sc->sense_map, sc->sense_frames, rsize,
            mpr_memaddr_cb, &sc->sense_busaddr, 0);
        mpr_dprint(sc, MPR_INIT, "sense frames busaddr= %#016jx size= %d\n",
            (uintmax_t)sc->sense_busaddr, rsize);

        /*
         * Allocate NVMe PRP Pages for NVMe SGL support only if the FW supports
         * these devices.
         */
        if ((sc->facts->MsgVersion >= MPI2_VERSION_02_06) &&
            (sc->facts->ProtocolFlags & MPI2_IOCFACTS_PROTOCOL_NVME_DEVICES)) {
                if (mpr_alloc_nvme_prp_pages(sc) == ENOMEM)
                        return (ENOMEM);
        }

        nsegs = (sc->maxio / PAGE_SIZE) + 1;
        if (bus_dma_tag_create( sc->mpr_parent_dmat,    /* parent */
                                1, 0,                   /* algnmnt, boundary */
                                BUS_SPACE_MAXADDR,      /* lowaddr */
                                BUS_SPACE_MAXADDR,      /* highaddr */
                                NULL, NULL,             /* filter, filterarg */
                                BUS_SPACE_MAXSIZE_32BIT,/* maxsize */
                                nsegs,                  /* nsegments */
                                BUS_SPACE_MAXSIZE_32BIT,/* maxsegsize */
                                BUS_DMA_ALLOCNOW,       /* flags */
                                busdma_lock_mutex,      /* lockfunc */
                                &sc->mpr_mtx,           /* lockarg */
                                &sc->buffer_dmat)) {
                mpr_dprint(sc, MPR_ERROR, "Cannot allocate buffer DMA tag\n");
                return (ENOMEM);
        }

        /*
         * SMID 0 cannot be used as a free command per the firmware spec.
         * Just drop that command instead of risking accounting bugs.
         */
        sc->commands = malloc(sizeof(struct mpr_command) * sc->num_reqs,
            M_MPR, M_WAITOK | M_ZERO);
        if (!sc->commands) {
                mpr_dprint(sc, MPR_ERROR, "Cannot allocate command memory\n");
                return (ENOMEM);
        }
        for (i = 1; i < sc->num_reqs; i++) {
                cm = &sc->commands[i];
                cm->cm_req = sc->req_frames + i * sc->reqframesz;
                cm->cm_req_busaddr = sc->req_busaddr + i * sc->reqframesz;
                cm->cm_sense = &sc->sense_frames[i];
                cm->cm_sense_busaddr = sc->sense_busaddr + i * MPR_SENSE_LEN;
                cm->cm_desc.Default.SMID = i;
                cm->cm_sc = sc;
                cm->cm_state = MPR_CM_STATE_BUSY;
                TAILQ_INIT(&cm->cm_chain_list);
                TAILQ_INIT(&cm->cm_prp_page_list);
                callout_init_mtx(&cm->cm_callout, &sc->mpr_mtx, 0);

                /* XXX Is a failure here a critical problem? */
                if (bus_dmamap_create(sc->buffer_dmat, 0, &cm->cm_dmamap)
                    == 0) {
                        if (i <= sc->num_prireqs)
                                mpr_free_high_priority_command(sc, cm);
                        else
                                mpr_free_command(sc, cm);
                } else {
                        panic("failed to allocate command %d\n", i);
                        sc->num_reqs = i;
                        break;
                }
        }

        return (0);
}

/*
 * Allocate contiguous buffers for PCIe NVMe devices for building native PRPs,
 * which are scatter/gather lists for NVMe devices. 
 *
 * This buffer must be contiguous due to the nature of how NVMe PRPs are built
 * and translated by FW.
 *
 * returns ENOMEM if memory could not be allocated, otherwise returns 0.
 */
static int
mpr_alloc_nvme_prp_pages(struct mpr_softc *sc)
{
        int PRPs_per_page, PRPs_required, pages_required;
        int rsize, i;
        struct mpr_prp_page *prp_page;

        /*
         * Assuming a MAX_IO_SIZE of 1MB and a PAGE_SIZE of 4k, the max number
         * of PRPs (NVMe's Scatter/Gather Element) needed per I/O is:
         * MAX_IO_SIZE / PAGE_SIZE = 256
         * 
         * 1 PRP entry in main frame for PRP list pointer still leaves 255 PRPs
         * required for the remainder of the 1MB I/O. 512 PRPs can fit into one
         * page (4096 / 8 = 512), so only one page is required for each I/O.
         *
         * Each of these buffers will need to be contiguous. For simplicity,
         * only one buffer is allocated here, which has all of the space
         * required for the NVMe Queue Depth. If there are problems allocating
         * this one buffer, this function will need to change to allocate
         * individual, contiguous NVME_QDEPTH buffers.
         *
         * The real calculation will use the real max io size. Above is just an
         * example.
         *
         */
        PRPs_required = sc->maxio / PAGE_SIZE;
        PRPs_per_page = (PAGE_SIZE / PRP_ENTRY_SIZE) - 1;
        pages_required = (PRPs_required / PRPs_per_page) + 1;

        sc->prp_buffer_size = PAGE_SIZE * pages_required; 
        rsize = sc->prp_buffer_size * NVME_QDEPTH; 
        if (bus_dma_tag_create( sc->mpr_parent_dmat,    /* parent */
                                4, 0,                   /* algnmnt, boundary */
                                BUS_SPACE_MAXADDR_32BIT,/* lowaddr */
                                BUS_SPACE_MAXADDR,      /* highaddr */
                                NULL, NULL,             /* filter, filterarg */
                                rsize,                  /* maxsize */
                                1,                      /* nsegments */
                                rsize,                  /* maxsegsize */
                                0,                      /* flags */
                                NULL, NULL,             /* lockfunc, lockarg */
                                &sc->prp_page_dmat)) {
                mpr_dprint(sc, MPR_ERROR, "Cannot allocate NVMe PRP DMA "
                    "tag\n");
                return (ENOMEM);
        }
        if (bus_dmamem_alloc(sc->prp_page_dmat, (void **)&sc->prp_pages,
            BUS_DMA_NOWAIT, &sc->prp_page_map)) {
                mpr_dprint(sc, MPR_ERROR, "Cannot allocate NVMe PRP memory\n");
                return (ENOMEM);
        }
        bzero(sc->prp_pages, rsize);
        bus_dmamap_load(sc->prp_page_dmat, sc->prp_page_map, sc->prp_pages,
            rsize, mpr_memaddr_cb, &sc->prp_page_busaddr, 0);

        sc->prps = malloc(sizeof(struct mpr_prp_page) * NVME_QDEPTH, M_MPR,
            M_WAITOK | M_ZERO);
        for (i = 0; i < NVME_QDEPTH; i++) {
                prp_page = &sc->prps[i];
                prp_page->prp_page = (uint64_t *)(sc->prp_pages +
                    i * sc->prp_buffer_size);
                prp_page->prp_page_busaddr = (uint64_t)(sc->prp_page_busaddr +
                    i * sc->prp_buffer_size);
                mpr_free_prp_page(sc, prp_page);
                sc->prp_pages_free_lowwater++;
        }

        return (0);
}

static int
mpr_init_queues(struct mpr_softc *sc)
{
        int i;

        memset((uint8_t *)sc->post_queue, 0xff, sc->pqdepth * 8);

        /*
         * According to the spec, we need to use one less reply than we
         * have space for on the queue.  So sc->num_replies (the number we
         * use) should be less than sc->fqdepth (allocated size).
         */
        if (sc->num_replies >= sc->fqdepth)
                return (EINVAL);

        /*
         * Initialize all of the free queue entries.
         */
        for (i = 0; i < sc->fqdepth; i++) {
                sc->free_queue[i] = sc->reply_busaddr + (i * sc->replyframesz);
        }
        sc->replyfreeindex = sc->num_replies;

        return (0);
}

/* Get the driver parameter tunables.  Lowest priority are the driver defaults.
 * Next are the global settings, if they exist.  Highest are the per-unit
 * settings, if they exist.
 */
void
mpr_get_tunables(struct mpr_softc *sc)
{
        char tmpstr[80], mpr_debug[80];

        /* XXX default to some debugging for now */
        sc->mpr_debug = MPR_INFO | MPR_FAULT;
        sc->disable_msix = 0;
        sc->disable_msi = 0;
        sc->max_msix = MPR_MSIX_MAX;
        sc->max_chains = MPR_CHAIN_FRAMES;
        sc->max_io_pages = MPR_MAXIO_PAGES;
        sc->enable_ssu = MPR_SSU_ENABLE_SSD_DISABLE_HDD;
        sc->spinup_wait_time = DEFAULT_SPINUP_WAIT;
        sc->use_phynum = 1;
        sc->max_reqframes = MPR_REQ_FRAMES;
        sc->max_prireqframes = MPR_PRI_REQ_FRAMES;
        sc->max_replyframes = MPR_REPLY_FRAMES;
        sc->max_evtframes = MPR_EVT_REPLY_FRAMES;

        /*
         * Grab the global variables.
         */
        bzero(mpr_debug, 80);
        if (TUNABLE_STR_FETCH("hw.mpr.debug_level", mpr_debug, 80) != 0)
                mpr_parse_debug(sc, mpr_debug);
        TUNABLE_INT_FETCH("hw.mpr.disable_msix", &sc->disable_msix);
        TUNABLE_INT_FETCH("hw.mpr.disable_msi", &sc->disable_msi);
        TUNABLE_INT_FETCH("hw.mpr.max_msix", &sc->max_msix);
        TUNABLE_INT_FETCH("hw.mpr.max_chains", &sc->max_chains);
        TUNABLE_INT_FETCH("hw.mpr.max_io_pages", &sc->max_io_pages);
        TUNABLE_INT_FETCH("hw.mpr.enable_ssu", &sc->enable_ssu);
        TUNABLE_INT_FETCH("hw.mpr.spinup_wait_time", &sc->spinup_wait_time);
        TUNABLE_INT_FETCH("hw.mpr.use_phy_num", &sc->use_phynum);
        TUNABLE_INT_FETCH("hw.mpr.max_reqframes", &sc->max_reqframes);
        TUNABLE_INT_FETCH("hw.mpr.max_prireqframes", &sc->max_prireqframes);
        TUNABLE_INT_FETCH("hw.mpr.max_replyframes", &sc->max_replyframes);
        TUNABLE_INT_FETCH("hw.mpr.max_evtframes", &sc->max_evtframes);

        /* Grab the unit-instance variables */
        snprintf(tmpstr, sizeof(tmpstr), "dev.mpr.%d.debug_level",
            device_get_unit(sc->mpr_dev));
        bzero(mpr_debug, 80);
        if (TUNABLE_STR_FETCH(tmpstr, mpr_debug, 80) != 0)
                mpr_parse_debug(sc, mpr_debug);

        snprintf(tmpstr, sizeof(tmpstr), "dev.mpr.%d.disable_msix",
            device_get_unit(sc->mpr_dev));
        TUNABLE_INT_FETCH(tmpstr, &sc->disable_msix);

        snprintf(tmpstr, sizeof(tmpstr), "dev.mpr.%d.disable_msi",
            device_get_unit(sc->mpr_dev));
        TUNABLE_INT_FETCH(tmpstr, &sc->disable_msi);

        snprintf(tmpstr, sizeof(tmpstr), "dev.mpr.%d.max_msix",
            device_get_unit(sc->mpr_dev));
        TUNABLE_INT_FETCH(tmpstr, &sc->max_msix);

        snprintf(tmpstr, sizeof(tmpstr), "dev.mpr.%d.max_chains",
            device_get_unit(sc->mpr_dev));
        TUNABLE_INT_FETCH(tmpstr, &sc->max_chains);

        snprintf(tmpstr, sizeof(tmpstr), "dev.mpr.%d.max_io_pages",
            device_get_unit(sc->mpr_dev));
        TUNABLE_INT_FETCH(tmpstr, &sc->max_io_pages);

        bzero(sc->exclude_ids, sizeof(sc->exclude_ids));
        snprintf(tmpstr, sizeof(tmpstr), "dev.mpr.%d.exclude_ids",
            device_get_unit(sc->mpr_dev));
        TUNABLE_STR_FETCH(tmpstr, sc->exclude_ids, sizeof(sc->exclude_ids));

        snprintf(tmpstr, sizeof(tmpstr), "dev.mpr.%d.enable_ssu",
            device_get_unit(sc->mpr_dev));
        TUNABLE_INT_FETCH(tmpstr, &sc->enable_ssu);

        snprintf(tmpstr, sizeof(tmpstr), "dev.mpr.%d.spinup_wait_time",
            device_get_unit(sc->mpr_dev));
        TUNABLE_INT_FETCH(tmpstr, &sc->spinup_wait_time);

        snprintf(tmpstr, sizeof(tmpstr), "dev.mpr.%d.use_phy_num",
            device_get_unit(sc->mpr_dev));
        TUNABLE_INT_FETCH(tmpstr, &sc->use_phynum);

        snprintf(tmpstr, sizeof(tmpstr), "dev.mpr.%d.max_reqframes",
            device_get_unit(sc->mpr_dev));
        TUNABLE_INT_FETCH(tmpstr, &sc->max_reqframes);

        snprintf(tmpstr, sizeof(tmpstr), "dev.mpr.%d.max_prireqframes",
            device_get_unit(sc->mpr_dev));
        TUNABLE_INT_FETCH(tmpstr, &sc->max_prireqframes);

        snprintf(tmpstr, sizeof(tmpstr), "dev.mpr.%d.max_replyframes",
            device_get_unit(sc->mpr_dev));
        TUNABLE_INT_FETCH(tmpstr, &sc->max_replyframes);

        snprintf(tmpstr, sizeof(tmpstr), "dev.mpr.%d.max_evtframes",
            device_get_unit(sc->mpr_dev));
        TUNABLE_INT_FETCH(tmpstr, &sc->max_evtframes);
}

static void
mpr_setup_sysctl(struct mpr_softc *sc)
{
        struct sysctl_ctx_list  *sysctl_ctx = NULL;
        struct sysctl_oid       *sysctl_tree = NULL;
        char tmpstr[80], tmpstr2[80];

        /*
         * Setup the sysctl variable so the user can change the debug level
         * on the fly.
         */
        snprintf(tmpstr, sizeof(tmpstr), "MPR controller %d",
            device_get_unit(sc->mpr_dev));
        snprintf(tmpstr2, sizeof(tmpstr2), "%d", device_get_unit(sc->mpr_dev));

        sysctl_ctx = device_get_sysctl_ctx(sc->mpr_dev);
        if (sysctl_ctx != NULL)
                sysctl_tree = device_get_sysctl_tree(sc->mpr_dev);

        if (sysctl_tree == NULL) {
                sysctl_ctx_init(&sc->sysctl_ctx);
                sc->sysctl_tree = SYSCTL_ADD_NODE(&sc->sysctl_ctx,
                    SYSCTL_STATIC_CHILDREN(_hw_mpr), OID_AUTO, tmpstr2,
                    CTLFLAG_RD, 0, tmpstr);
                if (sc->sysctl_tree == NULL)
                        return;
                sysctl_ctx = &sc->sysctl_ctx;
                sysctl_tree = sc->sysctl_tree;
        }

        SYSCTL_ADD_PROC(sysctl_ctx, SYSCTL_CHILDREN(sysctl_tree),
            OID_AUTO, "debug_level", CTLTYPE_STRING | CTLFLAG_RW | CTLFLAG_MPSAFE,
            sc, 0, mpr_debug_sysctl, "A", "mpr debug level");

        SYSCTL_ADD_INT(sysctl_ctx, SYSCTL_CHILDREN(sysctl_tree),
            OID_AUTO, "disable_msix", CTLFLAG_RD, &sc->disable_msix, 0,
            "Disable the use of MSI-X interrupts");

        SYSCTL_ADD_INT(sysctl_ctx, SYSCTL_CHILDREN(sysctl_tree),
            OID_AUTO, "max_msix", CTLFLAG_RD, &sc->max_msix, 0,
            "User-defined maximum number of MSIX queues");

        SYSCTL_ADD_INT(sysctl_ctx, SYSCTL_CHILDREN(sysctl_tree),
            OID_AUTO, "msix_msgs", CTLFLAG_RD, &sc->msi_msgs, 0,
            "Negotiated number of MSIX queues");

        SYSCTL_ADD_INT(sysctl_ctx, SYSCTL_CHILDREN(sysctl_tree),
            OID_AUTO, "max_reqframes", CTLFLAG_RD, &sc->max_reqframes, 0,
            "Total number of allocated request frames");

        SYSCTL_ADD_INT(sysctl_ctx, SYSCTL_CHILDREN(sysctl_tree),
            OID_AUTO, "max_prireqframes", CTLFLAG_RD, &sc->max_prireqframes, 0,
            "Total number of allocated high priority request frames");

        SYSCTL_ADD_INT(sysctl_ctx, SYSCTL_CHILDREN(sysctl_tree),
            OID_AUTO, "max_replyframes", CTLFLAG_RD, &sc->max_replyframes, 0,
            "Total number of allocated reply frames");

        SYSCTL_ADD_INT(sysctl_ctx, SYSCTL_CHILDREN(sysctl_tree),
            OID_AUTO, "max_evtframes", CTLFLAG_RD, &sc->max_evtframes, 0,
            "Total number of event frames allocated");

        SYSCTL_ADD_STRING(sysctl_ctx, SYSCTL_CHILDREN(sysctl_tree),
            OID_AUTO, "firmware_version", CTLFLAG_RW, sc->fw_version,
            strlen(sc->fw_version), "firmware version");

        SYSCTL_ADD_STRING(sysctl_ctx, SYSCTL_CHILDREN(sysctl_tree),
            OID_AUTO, "driver_version", CTLFLAG_RW, MPR_DRIVER_VERSION,
            strlen(MPR_DRIVER_VERSION), "driver version");

        SYSCTL_ADD_INT(sysctl_ctx, SYSCTL_CHILDREN(sysctl_tree),
            OID_AUTO, "io_cmds_active", CTLFLAG_RD,
            &sc->io_cmds_active, 0, "number of currently active commands");

        SYSCTL_ADD_INT(sysctl_ctx, SYSCTL_CHILDREN(sysctl_tree),
            OID_AUTO, "io_cmds_highwater", CTLFLAG_RD,
            &sc->io_cmds_highwater, 0, "maximum active commands seen");

        SYSCTL_ADD_INT(sysctl_ctx, SYSCTL_CHILDREN(sysctl_tree),
            OID_AUTO, "chain_free", CTLFLAG_RD,
            &sc->chain_free, 0, "number of free chain elements");

        SYSCTL_ADD_INT(sysctl_ctx, SYSCTL_CHILDREN(sysctl_tree),
            OID_AUTO, "chain_free_lowwater", CTLFLAG_RD,
            &sc->chain_free_lowwater, 0,"lowest number of free chain elements");

        SYSCTL_ADD_INT(sysctl_ctx, SYSCTL_CHILDREN(sysctl_tree),
            OID_AUTO, "max_chains", CTLFLAG_RD,
            &sc->max_chains, 0,"maximum chain frames that will be allocated");

        SYSCTL_ADD_INT(sysctl_ctx, SYSCTL_CHILDREN(sysctl_tree),
            OID_AUTO, "max_io_pages", CTLFLAG_RD,
            &sc->max_io_pages, 0,"maximum pages to allow per I/O (if <1 use "
            "IOCFacts)");

        SYSCTL_ADD_INT(sysctl_ctx, SYSCTL_CHILDREN(sysctl_tree),
            OID_AUTO, "enable_ssu", CTLFLAG_RW, &sc->enable_ssu, 0,
            "enable SSU to SATA SSD/HDD at shutdown");

        SYSCTL_ADD_UQUAD(sysctl_ctx, SYSCTL_CHILDREN(sysctl_tree),
            OID_AUTO, "chain_alloc_fail", CTLFLAG_RD,
            &sc->chain_alloc_fail, "chain allocation failures");

        SYSCTL_ADD_INT(sysctl_ctx, SYSCTL_CHILDREN(sysctl_tree),
            OID_AUTO, "spinup_wait_time", CTLFLAG_RD,
            &sc->spinup_wait_time, DEFAULT_SPINUP_WAIT, "seconds to wait for "
            "spinup after SATA ID error");

        SYSCTL_ADD_PROC(sysctl_ctx, SYSCTL_CHILDREN(sysctl_tree),
            OID_AUTO, "dump_reqs", CTLTYPE_OPAQUE | CTLFLAG_RD | CTLFLAG_SKIP, sc, 0,
            mpr_dump_reqs, "I", "Dump Active Requests");

        SYSCTL_ADD_INT(sysctl_ctx, SYSCTL_CHILDREN(sysctl_tree),
            OID_AUTO, "use_phy_num", CTLFLAG_RD, &sc->use_phynum, 0,
            "Use the phy number for enumeration");

        SYSCTL_ADD_INT(sysctl_ctx, SYSCTL_CHILDREN(sysctl_tree),
            OID_AUTO, "prp_pages_free", CTLFLAG_RD,
            &sc->prp_pages_free, 0, "number of free PRP pages");

        SYSCTL_ADD_INT(sysctl_ctx, SYSCTL_CHILDREN(sysctl_tree),
            OID_AUTO, "prp_pages_free_lowwater", CTLFLAG_RD,
            &sc->prp_pages_free_lowwater, 0,"lowest number of free PRP pages");

        SYSCTL_ADD_UQUAD(sysctl_ctx, SYSCTL_CHILDREN(sysctl_tree),
            OID_AUTO, "prp_page_alloc_fail", CTLFLAG_RD,
            &sc->prp_page_alloc_fail, "PRP page allocation failures");
}

static struct mpr_debug_string {
        char *name;
        int flag;
} mpr_debug_strings[] = {
        {"info", MPR_INFO},
        {"fault", MPR_FAULT},
        {"event", MPR_EVENT},
        {"log", MPR_LOG},
        {"recovery", MPR_RECOVERY},
        {"error", MPR_ERROR},
        {"init", MPR_INIT},
        {"xinfo", MPR_XINFO},
        {"user", MPR_USER},
        {"mapping", MPR_MAPPING},
        {"trace", MPR_TRACE}
};

enum mpr_debug_level_combiner {
        COMB_NONE,
        COMB_ADD,
        COMB_SUB
};

static int
mpr_debug_sysctl(SYSCTL_HANDLER_ARGS)
{
        struct mpr_softc *sc;
        struct mpr_debug_string *string;
        struct sbuf *sbuf;
        char *buffer;
        size_t sz;
        int i, len, debug, error;

        sc = (struct mpr_softc *)arg1;

        error = sysctl_wire_old_buffer(req, 0);
        if (error != 0)
                return (error);

        sbuf = sbuf_new_for_sysctl(NULL, NULL, 128, req);
        debug = sc->mpr_debug;

        sbuf_printf(sbuf, "%#x", debug);

        sz = sizeof(mpr_debug_strings) / sizeof(mpr_debug_strings[0]);
        for (i = 0; i < sz; i++) {
                string = &mpr_debug_strings[i];
                if (debug & string->flag) 
                        sbuf_printf(sbuf, ",%s", string->name);
        }

        error = sbuf_finish(sbuf);
        sbuf_delete(sbuf);

        if (error || req->newptr == NULL)
                return (error);

        len = req->newlen - req->newidx;
        if (len == 0)
                return (0);

        buffer = malloc(len, M_MPR, M_ZERO|M_WAITOK);
        error = SYSCTL_IN(req, buffer, len);

        mpr_parse_debug(sc, buffer);

        free(buffer, M_MPR);
        return (error);
}

static void
mpr_parse_debug(struct mpr_softc *sc, char *list)
{
        struct mpr_debug_string *string;
        enum mpr_debug_level_combiner op;
        char *token, *endtoken;
        size_t sz;
        int flags, i;

        if (list == NULL || *list == '\0')
                return;

        if (*list == '+') {
                op = COMB_ADD;
                list++;
        } else if (*list == '-') {
                op = COMB_SUB;
                list++;
        } else
                op = COMB_NONE;
        if (*list == '\0')
                return;

        flags = 0;
        sz = sizeof(mpr_debug_strings) / sizeof(mpr_debug_strings[0]);
        while ((token = strsep(&list, ":,")) != NULL) {

                /* Handle integer flags */
                flags |= strtol(token, &endtoken, 0);
                if (token != endtoken)
                        continue;

                /* Handle text flags */
                for (i = 0; i < sz; i++) {
                        string = &mpr_debug_strings[i];
                        if (strcasecmp(token, string->name) == 0) {
                                flags |= string->flag;
                                break;
                        }
                }
        }

        switch (op) {
        case COMB_NONE:
                sc->mpr_debug = flags;
                break;
        case COMB_ADD:
                sc->mpr_debug |= flags;
                break;
        case COMB_SUB:
                sc->mpr_debug &= (~flags);
                break;
        }
        return;
}

struct mpr_dumpreq_hdr {
        uint32_t        smid;
        uint32_t        state;
        uint32_t        numframes;
        uint32_t        deschi;
        uint32_t        desclo;
};

static int
mpr_dump_reqs(SYSCTL_HANDLER_ARGS)
{
        struct mpr_softc *sc;
        struct mpr_chain *chain, *chain1;
        struct mpr_command *cm;
        struct mpr_dumpreq_hdr hdr;
        struct sbuf *sb;
        uint32_t smid, state;
        int i, numreqs, error = 0;

        sc = (struct mpr_softc *)arg1;

        if ((error = priv_check(curthread, PRIV_DRIVER)) != 0) {
                printf("priv check error %d\n", error);
                return (error);
        }

        state = MPR_CM_STATE_INQUEUE;
        smid = 1;
        numreqs = sc->num_reqs;

        if (req->newptr != NULL)
                return (EINVAL);

        if (smid == 0 || smid > sc->num_reqs)
                return (EINVAL);
        if (numreqs <= 0 || (numreqs + smid > sc->num_reqs))
                numreqs = sc->num_reqs;
        sb = sbuf_new_for_sysctl(NULL, NULL, 4096, req);

        /* Best effort, no locking */
        for (i = smid; i < numreqs; i++) {
                cm = &sc->commands[i];
                if (cm->cm_state != state)
                        continue;
                hdr.smid = i;
                hdr.state = cm->cm_state;
                hdr.numframes = 1;
                hdr.deschi = cm->cm_desc.Words.High;
                hdr.desclo = cm->cm_desc.Words.Low;
                TAILQ_FOREACH_SAFE(chain, &cm->cm_chain_list, chain_link,
                   chain1)
                        hdr.numframes++;
                sbuf_bcat(sb, &hdr, sizeof(hdr));
                sbuf_bcat(sb, cm->cm_req, 128);
                TAILQ_FOREACH_SAFE(chain, &cm->cm_chain_list, chain_link,
                    chain1)
                        sbuf_bcat(sb, chain->chain, 128);
        }

        error = sbuf_finish(sb);
        sbuf_delete(sb);
        return (error);
}

int
mpr_attach(struct mpr_softc *sc)
{
        int error;

        MPR_FUNCTRACE(sc);
        mpr_dprint(sc, MPR_INIT, "%s entered\n", __func__);

        mtx_init(&sc->mpr_mtx, "MPR lock", NULL, MTX_DEF);
        callout_init_mtx(&sc->periodic, &sc->mpr_mtx, 0);
        callout_init_mtx(&sc->device_check_callout, &sc->mpr_mtx, 0);
        TAILQ_INIT(&sc->event_list);
        timevalclear(&sc->lastfail);

        if ((error = mpr_transition_ready(sc)) != 0) {
                mpr_dprint(sc, MPR_INIT|MPR_FAULT,
                    "Failed to transition ready\n");
                return (error);
        }

        sc->facts = malloc(sizeof(MPI2_IOC_FACTS_REPLY), M_MPR,
            M_ZERO|M_NOWAIT);
        if (!sc->facts) {
                mpr_dprint(sc, MPR_INIT|MPR_FAULT,
                    "Cannot allocate memory, exit\n");
                return (ENOMEM);
        }

        /*
         * Get IOC Facts and allocate all structures based on this information.
         * A Diag Reset will also call mpr_iocfacts_allocate and re-read the IOC
         * Facts. If relevant values have changed in IOC Facts, this function
         * will free all of the memory based on IOC Facts and reallocate that
         * memory.  If this fails, any allocated memory should already be freed.
         */
        if ((error = mpr_iocfacts_allocate(sc, TRUE)) != 0) {
                mpr_dprint(sc, MPR_INIT|MPR_FAULT, "IOC Facts allocation "
                    "failed with error %d\n", error);
                return (error);
        }

        /* Start the periodic watchdog check on the IOC Doorbell */
        mpr_periodic(sc);

        /*
         * The portenable will kick off discovery events that will drive the
         * rest of the initialization process.  The CAM/SAS module will
         * hold up the boot sequence until discovery is complete.
         */
        sc->mpr_ich.ich_func = mpr_startup;
        sc->mpr_ich.ich_arg = sc;
        if (config_intrhook_establish(&sc->mpr_ich) != 0) {
                mpr_dprint(sc, MPR_INIT|MPR_ERROR,
                    "Cannot establish MPR config hook\n");
                error = EINVAL;
        }

        /*
         * Allow IR to shutdown gracefully when shutdown occurs.
         */
        sc->shutdown_eh = EVENTHANDLER_REGISTER(shutdown_final,
            mprsas_ir_shutdown, sc, SHUTDOWN_PRI_DEFAULT);

        if (sc->shutdown_eh == NULL)
                mpr_dprint(sc, MPR_INIT|MPR_ERROR,
                    "shutdown event registration failed\n");

        mpr_setup_sysctl(sc);

        sc->mpr_flags |= MPR_FLAGS_ATTACH_DONE;
        mpr_dprint(sc, MPR_INIT, "%s exit error= %d\n", __func__, error);

        return (error);
}

/* Run through any late-start handlers. */
static void
mpr_startup(void *arg)
{
        struct mpr_softc *sc;

        sc = (struct mpr_softc *)arg;
        mpr_dprint(sc, MPR_INIT, "%s entered\n", __func__);

        mpr_lock(sc);
        mpr_unmask_intr(sc);

        /* initialize device mapping tables */
        mpr_base_static_config_pages(sc);
        mpr_mapping_initialize(sc);
        mprsas_startup(sc);
        mpr_unlock(sc);

        mpr_dprint(sc, MPR_INIT, "disestablish config intrhook\n");
        config_intrhook_disestablish(&sc->mpr_ich);
        sc->mpr_ich.ich_arg = NULL;

        mpr_dprint(sc, MPR_INIT, "%s exit\n", __func__);
}

/* Periodic watchdog.  Is called with the driver lock already held. */
static void
mpr_periodic(void *arg)
{
        struct mpr_softc *sc;
        uint32_t db;

        sc = (struct mpr_softc *)arg;
        if (sc->mpr_flags & MPR_FLAGS_SHUTDOWN)
                return;

        db = mpr_regread(sc, MPI2_DOORBELL_OFFSET);
        if ((db & MPI2_IOC_STATE_MASK) == MPI2_IOC_STATE_FAULT) {
                if ((db & MPI2_DOORBELL_FAULT_CODE_MASK) ==
                    IFAULT_IOP_OVER_TEMP_THRESHOLD_EXCEEDED) {
                        panic("TEMPERATURE FAULT: STOPPING.");
                }
                mpr_dprint(sc, MPR_FAULT, "IOC Fault 0x%08x, Resetting\n", db);
                mpr_reinit(sc);
        }

        callout_reset(&sc->periodic, MPR_PERIODIC_DELAY * hz, mpr_periodic, sc);
}

static void
mpr_log_evt_handler(struct mpr_softc *sc, uintptr_t data,
    MPI2_EVENT_NOTIFICATION_REPLY *event)
{
        MPI2_EVENT_DATA_LOG_ENTRY_ADDED *entry;

        MPR_DPRINT_EVENT(sc, generic, event);

        switch (event->Event) {
        case MPI2_EVENT_LOG_DATA:
                mpr_dprint(sc, MPR_EVENT, "MPI2_EVENT_LOG_DATA:\n");
                if (sc->mpr_debug & MPR_EVENT)
                        hexdump(event->EventData, event->EventDataLength, NULL,
                            0);
                break;
        case MPI2_EVENT_LOG_ENTRY_ADDED:
                entry = (MPI2_EVENT_DATA_LOG_ENTRY_ADDED *)event->EventData;
                mpr_dprint(sc, MPR_EVENT, "MPI2_EVENT_LOG_ENTRY_ADDED event "
                    "0x%x Sequence %d:\n", entry->LogEntryQualifier,
                     entry->LogSequence);
                break;
        default:
                break;
        }
        return;
}

static int
mpr_attach_log(struct mpr_softc *sc)
{
        uint8_t events[16];

        bzero(events, 16);
        setbit(events, MPI2_EVENT_LOG_DATA);
        setbit(events, MPI2_EVENT_LOG_ENTRY_ADDED);

        mpr_register_events(sc, events, mpr_log_evt_handler, NULL,
            &sc->mpr_log_eh);

        return (0);
}

static int
mpr_detach_log(struct mpr_softc *sc)
{

        if (sc->mpr_log_eh != NULL)
                mpr_deregister_events(sc, sc->mpr_log_eh);
        return (0);
}

/*
 * Free all of the driver resources and detach submodules.  Should be called
 * without the lock held.
 */
int
mpr_free(struct mpr_softc *sc)
{
        int error;

        mpr_dprint(sc, MPR_INIT, "%s entered\n", __func__);
        /* Turn off the watchdog */
        mpr_lock(sc);
        sc->mpr_flags |= MPR_FLAGS_SHUTDOWN;
        mpr_unlock(sc);
        /* Lock must not be held for this */
        callout_drain(&sc->periodic);
        callout_drain(&sc->device_check_callout);

        if (((error = mpr_detach_log(sc)) != 0) ||
            ((error = mpr_detach_sas(sc)) != 0)) {
                mpr_dprint(sc, MPR_INIT|MPR_FAULT, "failed to detach "
                    "subsystems, error= %d, exit\n", error);
                return (error);
        }

        mpr_detach_user(sc);

        /* Put the IOC back in the READY state. */
        mpr_lock(sc);
        if ((error = mpr_transition_ready(sc)) != 0) {
                mpr_unlock(sc);
                return (error);
        }
        mpr_unlock(sc);

        if (sc->facts != NULL)
                free(sc->facts, M_MPR);

        /*
         * Free all buffers that are based on IOC Facts.  A Diag Reset may need
         * to free these buffers too.
         */
        mpr_iocfacts_free(sc);

        if (sc->sysctl_tree != NULL)
                sysctl_ctx_free(&sc->sysctl_ctx);

        /* Deregister the shutdown function */
        if (sc->shutdown_eh != NULL)
                EVENTHANDLER_DEREGISTER(shutdown_final, sc->shutdown_eh);

        mtx_destroy(&sc->mpr_mtx);
        mpr_dprint(sc, MPR_INIT, "%s exit\n", __func__);

        return (0);
}

static __inline void
mpr_complete_command(struct mpr_softc *sc, struct mpr_command *cm)
{
        MPR_FUNCTRACE(sc);

        if (cm == NULL) {
                mpr_dprint(sc, MPR_ERROR, "Completing NULL command\n");
                return;
        }

        cm->cm_state = MPR_CM_STATE_BUSY;
        if (cm->cm_flags & MPR_CM_FLAGS_POLLED)
                cm->cm_flags |= MPR_CM_FLAGS_COMPLETE;

        if (cm->cm_complete != NULL) {
                mpr_dprint(sc, MPR_TRACE,
                    "%s cm %p calling cm_complete %p data %p reply %p\n",
                    __func__, cm, cm->cm_complete, cm->cm_complete_data,
                    cm->cm_reply);
                cm->cm_complete(sc, cm);
        }

        if (cm->cm_flags & MPR_CM_FLAGS_WAKEUP) {
                mpr_dprint(sc, MPR_TRACE, "waking up %p\n", cm);
                wakeup(cm);
        }

        if (sc->io_cmds_active != 0) {
                sc->io_cmds_active--;
        } else {
                mpr_dprint(sc, MPR_ERROR, "Warning: io_cmds_active is "
                    "out of sync - resynching to 0\n");
        }
}

static void
mpr_sas_log_info(struct mpr_softc *sc , u32 log_info)
{
        union loginfo_type {
                u32     loginfo;
                struct {
                        u32     subcode:16;
                        u32     code:8;
                        u32     originator:4;
                        u32     bus_type:4;
                } dw;
        };
        union loginfo_type sas_loginfo;
        char *originator_str = NULL;
 
        sas_loginfo.loginfo = log_info;
        if (sas_loginfo.dw.bus_type != 3 /*SAS*/)
                return;
 
        /* each nexus loss loginfo */
        if (log_info == 0x31170000)
                return;
 
        /* eat the loginfos associated with task aborts */
        if ((log_info == 30050000) || (log_info == 0x31140000) ||
            (log_info == 0x31130000))
                return;
 
        switch (sas_loginfo.dw.originator) {
        case 0:
                originator_str = "IOP";
                break;
        case 1:
                originator_str = "PL";
                break;
        case 2:
                originator_str = "IR";
                break;
        }
 
        mpr_dprint(sc, MPR_LOG, "log_info(0x%08x): originator(%s), "
            "code(0x%02x), sub_code(0x%04x)\n", log_info, originator_str,
            sas_loginfo.dw.code, sas_loginfo.dw.subcode);
}

static void
mpr_display_reply_info(struct mpr_softc *sc, uint8_t *reply)
{
        MPI2DefaultReply_t *mpi_reply;
        u16 sc_status;
 
        mpi_reply = (MPI2DefaultReply_t*)reply;
        sc_status = le16toh(mpi_reply->IOCStatus);
        if (sc_status & MPI2_IOCSTATUS_FLAG_LOG_INFO_AVAILABLE)
                mpr_sas_log_info(sc, le32toh(mpi_reply->IOCLogInfo));
}

void
mpr_intr(void *data)
{
        struct mpr_softc *sc;
        uint32_t status;

        sc = (struct mpr_softc *)data;
        mpr_dprint(sc, MPR_TRACE, "%s\n", __func__);

        /*
         * Check interrupt status register to flush the bus.  This is
         * needed for both INTx interrupts and driver-driven polling
         */
        status = mpr_regread(sc, MPI2_HOST_INTERRUPT_STATUS_OFFSET);
        if ((status & MPI2_HIS_REPLY_DESCRIPTOR_INTERRUPT) == 0)
                return;

        mpr_lock(sc);
        mpr_intr_locked(data);
        mpr_unlock(sc);
        return;
}

/*
 * In theory, MSI/MSIX interrupts shouldn't need to read any registers on the
 * chip.  Hopefully this theory is correct.
 */
void
mpr_intr_msi(void *data)
{
        struct mpr_softc *sc;

        sc = (struct mpr_softc *)data;
        mpr_dprint(sc, MPR_TRACE, "%s\n", __func__);
        mpr_lock(sc);
        mpr_intr_locked(data);
        mpr_unlock(sc);
        return;
}

/*
 * The locking is overly broad and simplistic, but easy to deal with for now.
 */
void
mpr_intr_locked(void *data)
{
        MPI2_REPLY_DESCRIPTORS_UNION *desc;
        MPI2_DIAG_RELEASE_REPLY *rel_rep;
        mpr_fw_diagnostic_buffer_t *pBuffer;
        struct mpr_softc *sc;
        uint64_t tdesc;
        struct mpr_command *cm = NULL;
        uint8_t flags;
        u_int pq;

        sc = (struct mpr_softc *)data;

        pq = sc->replypostindex;
        mpr_dprint(sc, MPR_TRACE,
            "%s sc %p starting with replypostindex %u\n", 
            __func__, sc, sc->replypostindex);

        for ( ;; ) {
                cm = NULL;
                desc = &sc->post_queue[sc->replypostindex];

                /*
                 * Copy and clear out the descriptor so that any reentry will
                 * immediately know that this descriptor has already been
                 * looked at.  There is unfortunate casting magic because the
                 * MPI API doesn't have a cardinal 64bit type.
                 */
                tdesc = 0xffffffffffffffff;
                tdesc = atomic_swap_64((uint64_t *)desc, tdesc);
                desc = (MPI2_REPLY_DESCRIPTORS_UNION *)&tdesc;

                flags = desc->Default.ReplyFlags &
                    MPI2_RPY_DESCRIPT_FLAGS_TYPE_MASK;
                if ((flags == MPI2_RPY_DESCRIPT_FLAGS_UNUSED) ||
                    (le32toh(desc->Words.High) == 0xffffffff))
                        break;

                /* increment the replypostindex now, so that event handlers
                 * and cm completion handlers which decide to do a diag
                 * reset can zero it without it getting incremented again
                 * afterwards, and we break out of this loop on the next
                 * iteration since the reply post queue has been cleared to
                 * 0xFF and all descriptors look unused (which they are).
                 */
                if (++sc->replypostindex >= sc->pqdepth)
                        sc->replypostindex = 0;

                switch (flags) {
                case MPI2_RPY_DESCRIPT_FLAGS_SCSI_IO_SUCCESS:
                case MPI25_RPY_DESCRIPT_FLAGS_FAST_PATH_SCSI_IO_SUCCESS:
                case MPI26_RPY_DESCRIPT_FLAGS_PCIE_ENCAPSULATED_SUCCESS:
                        cm = &sc->commands[le16toh(desc->SCSIIOSuccess.SMID)];
                        KASSERT(cm->cm_state == MPR_CM_STATE_INQUEUE,
                            ("command not inqueue\n"));
                        cm->cm_state = MPR_CM_STATE_BUSY;
                        cm->cm_reply = NULL;
                        break;
                case MPI2_RPY_DESCRIPT_FLAGS_ADDRESS_REPLY:
                {
                        uint32_t baddr;
                        uint8_t *reply;

                        /*
                         * Re-compose the reply address from the address
                         * sent back from the chip.  The ReplyFrameAddress
                         * is the lower 32 bits of the physical address of
                         * particular reply frame.  Convert that address to
                         * host format, and then use that to provide the
                         * offset against the virtual address base
                         * (sc->reply_frames).
                         */
                        baddr = le32toh(desc->AddressReply.ReplyFrameAddress);
                        reply = sc->reply_frames +
                                (baddr - ((uint32_t)sc->reply_busaddr));
                        /*
                         * Make sure the reply we got back is in a valid
                         * range.  If not, go ahead and panic here, since
                         * we'll probably panic as soon as we deference the
                         * reply pointer anyway.
                         */
                        if ((reply < sc->reply_frames)
                         || (reply > (sc->reply_frames +
                             (sc->fqdepth * sc->replyframesz)))) {
                                printf("%s: WARNING: reply %p out of range!\n",
                                       __func__, reply);
                                printf("%s: reply_frames %p, fqdepth %d, "
                                       "frame size %d\n", __func__,
                                       sc->reply_frames, sc->fqdepth,
                                       sc->replyframesz);
                                printf("%s: baddr %#x,\n", __func__, baddr);
                                /* LSI-TODO. See Linux Code for Graceful exit */
                                panic("Reply address out of range");
                        }
                        if (le16toh(desc->AddressReply.SMID) == 0) {
                                if (((MPI2_DEFAULT_REPLY *)reply)->Function ==
                                    MPI2_FUNCTION_DIAG_BUFFER_POST) {
                                        /*
                                         * If SMID is 0 for Diag Buffer Post,
                                         * this implies that the reply is due to
                                         * a release function with a status that
                                         * the buffer has been released.  Set
                                         * the buffer flags accordingly.
                                         */
                                        rel_rep =
                                            (MPI2_DIAG_RELEASE_REPLY *)reply;
                                        if ((le16toh(rel_rep->IOCStatus) &
                                            MPI2_IOCSTATUS_MASK) ==
                                            MPI2_IOCSTATUS_DIAGNOSTIC_RELEASED)
                                        {
                                                pBuffer =
                                                    &sc->fw_diag_buffer_list[
                                                    rel_rep->BufferType];
                                                pBuffer->valid_data = TRUE;
                                                pBuffer->owned_by_firmware =
                                                    FALSE;
                                                pBuffer->immediate = FALSE;
                                        }
                                } else
                                        mpr_dispatch_event(sc, baddr,
                                            (MPI2_EVENT_NOTIFICATION_REPLY *)
                                            reply);
                        } else {
                                cm = &sc->commands[
                                    le16toh(desc->AddressReply.SMID)];
                                if (cm->cm_state == MPR_CM_STATE_INQUEUE) {
                                        cm->cm_reply = reply;
                                        cm->cm_reply_data =
                                            le32toh(desc->AddressReply.
                                                ReplyFrameAddress);
                                } else {
                                        mpr_dprint(sc, MPR_RECOVERY,
                                            "Bad state for ADDRESS_REPLY status,"
                                            " ignoring state %d cm %p\n",
                                            cm->cm_state, cm);
                                }
                        }
                        break;
                }
                case MPI2_RPY_DESCRIPT_FLAGS_TARGETASSIST_SUCCESS:
                case MPI2_RPY_DESCRIPT_FLAGS_TARGET_COMMAND_BUFFER:
                case MPI2_RPY_DESCRIPT_FLAGS_RAID_ACCELERATOR_SUCCESS:
                default:
                        /* Unhandled */
                        mpr_dprint(sc, MPR_ERROR, "Unhandled reply 0x%x\n",
                            desc->Default.ReplyFlags);
                        cm = NULL;
                        break;
                }

                if (cm != NULL) {
                        // Print Error reply frame
                        if (cm->cm_reply)
                                mpr_display_reply_info(sc,cm->cm_reply);
                        mpr_complete_command(sc, cm);
                }
        }

        if (pq != sc->replypostindex) {
                mpr_dprint(sc, MPR_TRACE, "%s sc %p writing postindex %d\n",
                    __func__, sc, sc->replypostindex);
                mpr_regwrite(sc, MPI2_REPLY_POST_HOST_INDEX_OFFSET,
                    sc->replypostindex);
        }

        return;
}

static void
mpr_dispatch_event(struct mpr_softc *sc, uintptr_t data,
    MPI2_EVENT_NOTIFICATION_REPLY *reply)
{
        struct mpr_event_handle *eh;
        int event, handled = 0;

        event = le16toh(reply->Event);
        TAILQ_FOREACH(eh, &sc->event_list, eh_list) {
                if (isset(eh->mask, event)) {
                        eh->callback(sc, data, reply);
                        handled++;
                }
        }

        if (handled == 0)
                mpr_dprint(sc, MPR_EVENT, "Unhandled event 0x%x\n",
                    le16toh(event));

        /*
         * This is the only place that the event/reply should be freed.
         * Anything wanting to hold onto the event data should have
         * already copied it into their own storage.
         */
        mpr_free_reply(sc, data);
}

static void
mpr_reregister_events_complete(struct mpr_softc *sc, struct mpr_command *cm)
{
        mpr_dprint(sc, MPR_TRACE, "%s\n", __func__);

        if (cm->cm_reply)
                MPR_DPRINT_EVENT(sc, generic,
                        (MPI2_EVENT_NOTIFICATION_REPLY *)cm->cm_reply);

        mpr_free_command(sc, cm);

        /* next, send a port enable */
        mprsas_startup(sc);
}

/*
 * For both register_events and update_events, the caller supplies a bitmap
 * of events that it _wants_.  These functions then turn that into a bitmask
 * suitable for the controller.
 */
int
mpr_register_events(struct mpr_softc *sc, uint8_t *mask,
    mpr_evt_callback_t *cb, void *data, struct mpr_event_handle **handle)
{
        struct mpr_event_handle *eh;
        int error = 0;

        eh = malloc(sizeof(struct mpr_event_handle), M_MPR, M_WAITOK|M_ZERO);
        if (!eh) {
                mpr_dprint(sc, MPR_EVENT|MPR_ERROR,
                    "Cannot allocate event memory\n");
                return (ENOMEM);
        }
        eh->callback = cb;
        eh->data = data;
        TAILQ_INSERT_TAIL(&sc->event_list, eh, eh_list);
        if (mask != NULL)
                error = mpr_update_events(sc, eh, mask);
        *handle = eh;

        return (error);
}

int
mpr_update_events(struct mpr_softc *sc, struct mpr_event_handle *handle,
    uint8_t *mask)
{
        MPI2_EVENT_NOTIFICATION_REQUEST *evtreq;
        MPI2_EVENT_NOTIFICATION_REPLY *reply = NULL;
        struct mpr_command *cm = NULL;
        struct mpr_event_handle *eh;
        int error, i;

        mpr_dprint(sc, MPR_TRACE, "%s\n", __func__);

        if ((mask != NULL) && (handle != NULL))
                bcopy(mask, &handle->mask[0], 16);
        memset(sc->event_mask, 0xff, 16);

        TAILQ_FOREACH(eh, &sc->event_list, eh_list) {
                for (i = 0; i < 16; i++)
                        sc->event_mask[i] &= ~eh->mask[i];
        }

        if ((cm = mpr_alloc_command(sc)) == NULL)
                return (EBUSY);
        evtreq = (MPI2_EVENT_NOTIFICATION_REQUEST *)cm->cm_req;
        evtreq->Function = MPI2_FUNCTION_EVENT_NOTIFICATION;
        evtreq->MsgFlags = 0;
        evtreq->SASBroadcastPrimitiveMasks = 0;
#ifdef MPR_DEBUG_ALL_EVENTS
        {
                u_char fullmask[16];
                memset(fullmask, 0x00, 16);
                bcopy(fullmask, (uint8_t *)&evtreq->EventMasks, 16);
        }
#else
                bcopy(sc->event_mask, (uint8_t *)&evtreq->EventMasks, 16);
#endif
        cm->cm_desc.Default.RequestFlags = MPI2_REQ_DESCRIPT_FLAGS_DEFAULT_TYPE;
        cm->cm_data = NULL;

        error = mpr_request_polled(sc, &cm);
        if (cm != NULL)
                reply = (MPI2_EVENT_NOTIFICATION_REPLY *)cm->cm_reply;
        if ((reply == NULL) ||
            (reply->IOCStatus & MPI2_IOCSTATUS_MASK) != MPI2_IOCSTATUS_SUCCESS)
                error = ENXIO;
        
        if (reply)
                MPR_DPRINT_EVENT(sc, generic, reply);

        mpr_dprint(sc, MPR_TRACE, "%s finished error %d\n", __func__, error);

        if (cm != NULL)
                mpr_free_command(sc, cm);
        return (error);
}

static int
mpr_reregister_events(struct mpr_softc *sc)
{
        MPI2_EVENT_NOTIFICATION_REQUEST *evtreq;
        struct mpr_command *cm;
        struct mpr_event_handle *eh;
        int error, i;

        mpr_dprint(sc, MPR_TRACE, "%s\n", __func__);

        /* first, reregister events */

        memset(sc->event_mask, 0xff, 16);

        TAILQ_FOREACH(eh, &sc->event_list, eh_list) {
                for (i = 0; i < 16; i++)
                        sc->event_mask[i] &= ~eh->mask[i];
        }

        if ((cm = mpr_alloc_command(sc)) == NULL)
                return (EBUSY);
        evtreq = (MPI2_EVENT_NOTIFICATION_REQUEST *)cm->cm_req;
        evtreq->Function = MPI2_FUNCTION_EVENT_NOTIFICATION;
        evtreq->MsgFlags = 0;
        evtreq->SASBroadcastPrimitiveMasks = 0;
#ifdef MPR_DEBUG_ALL_EVENTS
        {
                u_char fullmask[16];
                memset(fullmask, 0x00, 16);
                bcopy(fullmask, (uint8_t *)&evtreq->EventMasks, 16);
        }
#else
                bcopy(sc->event_mask, (uint8_t *)&evtreq->EventMasks, 16);
#endif
        cm->cm_desc.Default.RequestFlags = MPI2_REQ_DESCRIPT_FLAGS_DEFAULT_TYPE;
        cm->cm_data = NULL;
        cm->cm_complete = mpr_reregister_events_complete;

        error = mpr_map_command(sc, cm);

        mpr_dprint(sc, MPR_TRACE, "%s finished with error %d\n", __func__,
            error);
        return (error);
}

int
mpr_deregister_events(struct mpr_softc *sc, struct mpr_event_handle *handle)
{

        TAILQ_REMOVE(&sc->event_list, handle, eh_list);
        free(handle, M_MPR);
        return (mpr_update_events(sc, NULL, NULL));
}

/**
* mpr_build_nvme_prp - This function is called for NVMe end devices to build a
* native SGL (NVMe PRP). The native SGL is built starting in the first PRP entry
* of the NVMe message (PRP1). If the data buffer is small enough to be described
* entirely using PRP1, then PRP2 is not used. If needed, PRP2 is used to
* describe a larger data buffer. If the data buffer is too large to describe
* using the two PRP entriess inside the NVMe message, then PRP1 describes the
* first data memory segment, and PRP2 contains a pointer to a PRP list located
* elsewhere in memory to describe the remaining data memory segments. The PRP
* list will be contiguous.

* The native SGL for NVMe devices is a Physical Region Page (PRP). A PRP
* consists of a list of PRP entries to describe a number of noncontigous
* physical memory segments as a single memory buffer, just as a SGL does. Note
* however, that this function is only used by the IOCTL call, so the memory
* given will be guaranteed to be contiguous. There is no need to translate
* non-contiguous SGL into a PRP in this case. All PRPs will describe contiguous
* space that is one page size each.
*
* Each NVMe message contains two PRP entries. The first (PRP1) either contains
* a PRP list pointer or a PRP element, depending upon the command. PRP2 contains
* the second PRP element if the memory being described fits within 2 PRP
* entries, or a PRP list pointer if the PRP spans more than two entries.
*
* A PRP list pointer contains the address of a PRP list, structured as a linear
* array of PRP entries. Each PRP entry in this list describes a segment of
* physical memory.
*
* Each 64-bit PRP entry comprises an address and an offset field. The address
* always points to the beginning of a PAGE_SIZE physical memory page, and the
* offset describes where within that page the memory segment begins. Only the
* first element in a PRP list may contain a non-zero offest, implying that all
* memory segments following the first begin at the start of a PAGE_SIZE page.
*
* Each PRP element normally describes a chunck of PAGE_SIZE physical memory,
* with exceptions for the first and last elements in the list. If the memory
* being described by the list begins at a non-zero offset within the first page,
* then the first PRP element will contain a non-zero offset indicating where the
* region begins within the page. The last memory segment may end before the end
* of the PAGE_SIZE segment, depending upon the overall size of the memory being
* described by the PRP list. 
*
* Since PRP entries lack any indication of size, the overall data buffer length
* is used to determine where the end of the data memory buffer is located, and
* how many PRP entries are required to describe it.
*
* Returns nothing.
*/
void 
mpr_build_nvme_prp(struct mpr_softc *sc, struct mpr_command *cm,
    Mpi26NVMeEncapsulatedRequest_t *nvme_encap_request, void *data,
    uint32_t data_in_sz, uint32_t data_out_sz)
{
        int                     prp_size = PRP_ENTRY_SIZE;
        uint64_t                *prp_entry, *prp1_entry, *prp2_entry;
        uint64_t                *prp_entry_phys, *prp_page, *prp_page_phys;
        uint32_t                offset, entry_len, page_mask_result, page_mask;
        bus_addr_t              paddr;
        size_t                  length;
        struct mpr_prp_page     *prp_page_info = NULL;

        /*
         * Not all commands require a data transfer. If no data, just return
         * without constructing any PRP.
         */
        if (!data_in_sz && !data_out_sz)
                return;

        /*
         * Set pointers to PRP1 and PRP2, which are in the NVMe command. PRP1 is
         * located at a 24 byte offset from the start of the NVMe command. Then
         * set the current PRP entry pointer to PRP1.
         */
        prp1_entry = (uint64_t *)(nvme_encap_request->NVMe_Command +
            NVME_CMD_PRP1_OFFSET);
        prp2_entry = (uint64_t *)(nvme_encap_request->NVMe_Command +
            NVME_CMD_PRP2_OFFSET);
        prp_entry = prp1_entry;

        /*
         * For the PRP entries, use the specially allocated buffer of
         * contiguous memory. PRP Page allocation failures should not happen
         * because there should be enough PRP page buffers to account for the
         * possible NVMe QDepth.
         */
        prp_page_info = mpr_alloc_prp_page(sc);
        KASSERT(prp_page_info != NULL, ("%s: There are no PRP Pages left to be "
            "used for building a native NVMe SGL.\n", __func__));
        prp_page = (uint64_t *)prp_page_info->prp_page;
        prp_page_phys = (uint64_t *)(uintptr_t)prp_page_info->prp_page_busaddr;

        /*
         * Insert the allocated PRP page into the command's PRP page list. This
         * will be freed when the command is freed.
         */
        TAILQ_INSERT_TAIL(&cm->cm_prp_page_list, prp_page_info, prp_page_link);

        /*
         * Check if we are within 1 entry of a page boundary we don't want our
         * first entry to be a PRP List entry.
         */
        page_mask = PAGE_SIZE - 1;
        page_mask_result = (uintptr_t)((uint8_t *)prp_page + prp_size) &
            page_mask;
        if (!page_mask_result)
        {
                /* Bump up to next page boundary. */
                prp_page = (uint64_t *)((uint8_t *)prp_page + prp_size);
                prp_page_phys = (uint64_t *)((uint8_t *)prp_page_phys +
                    prp_size);
        }

        /*
         * Set PRP physical pointer, which initially points to the current PRP
         * DMA memory page.
         */
        prp_entry_phys = prp_page_phys;

        /* Get physical address and length of the data buffer. */
        paddr = (bus_addr_t)(uintptr_t)data;
        if (data_in_sz)
                length = data_in_sz;
        else
                length = data_out_sz;

        /* Loop while the length is not zero. */
        while (length)
        {
                /*
                 * Check if we need to put a list pointer here if we are at page
                 * boundary - prp_size (8 bytes).
                 */
                page_mask_result = (uintptr_t)((uint8_t *)prp_entry_phys +
                    prp_size) & page_mask;
                if (!page_mask_result)
                {
                        /*
                         * This is the last entry in a PRP List, so we need to
                         * put a PRP list pointer here. What this does is:
                         *   - bump the current memory pointer to the next
                         *     address, which will be the next full page.
                         *   - set the PRP Entry to point to that page. This is
                         *     now the PRP List pointer.
                         *   - bump the PRP Entry pointer the start of the next
                         *     page. Since all of this PRP memory is contiguous,
                         *     no need to get a new page - it's just the next
                         *     address.
                         */
                        prp_entry_phys++;
                        *prp_entry =
                            htole64((uint64_t)(uintptr_t)prp_entry_phys);
                        prp_entry++;
                }

                /* Need to handle if entry will be part of a page. */
                offset = (uint32_t)paddr & page_mask;
                entry_len = PAGE_SIZE - offset;

                if (prp_entry == prp1_entry)
                {
                        /*
                         * Must fill in the first PRP pointer (PRP1) before
                         * moving on.
                         */
                        *prp1_entry = htole64((uint64_t)paddr);

                        /*
                         * Now point to the second PRP entry within the
                         * command (PRP2).
                         */
                        prp_entry = prp2_entry;
                }
                else if (prp_entry == prp2_entry)
                {
                        /*
                         * Should the PRP2 entry be a PRP List pointer or just a
                         * regular PRP pointer? If there is more than one more
                         * page of data, must use a PRP List pointer.
                         */
                        if (length > PAGE_SIZE)
                        {
                                /*
                                 * PRP2 will contain a PRP List pointer because
                                 * more PRP's are needed with this command. The
                                 * list will start at the beginning of the
                                 * contiguous buffer.
                                 */
                                *prp2_entry =
                                    htole64(
                                    (uint64_t)(uintptr_t)prp_entry_phys);

                                /*
                                 * The next PRP Entry will be the start of the
                                 * first PRP List.
                                 */
                                prp_entry = prp_page;
                        }
                        else
                        {
                                /*
                                 * After this, the PRP Entries are complete.
                                 * This command uses 2 PRP's and no PRP list.
                                 */
                                *prp2_entry = htole64((uint64_t)paddr);
                        }
                }
                else
                {
                        /*
                         * Put entry in list and bump the addresses.
                         *
                         * After PRP1 and PRP2 are filled in, this will fill in
                         * all remaining PRP entries in a PRP List, one per each
                         * time through the loop.
                         */
                        *prp_entry = htole64((uint64_t)paddr);
                        prp_entry++;
                        prp_entry_phys++;
                }

                /*
                 * Bump the phys address of the command's data buffer by the
                 * entry_len.
                 */
                paddr += entry_len;

                /* Decrement length accounting for last partial page. */
                if (entry_len > length)
                        length = 0;
                else
                        length -= entry_len;
        }
}

/*
 * mpr_check_pcie_native_sgl - This function is called for PCIe end devices to
 * determine if the driver needs to build a native SGL. If so, that native SGL
 * is built in the contiguous buffers allocated especially for PCIe SGL
 * creation. If the driver will not build a native SGL, return TRUE and a
 * normal IEEE SGL will be built. Currently this routine supports NVMe devices
 * only.
 *
 * Returns FALSE (0) if native SGL was built, TRUE (1) if no SGL was built.
 */
static int
mpr_check_pcie_native_sgl(struct mpr_softc *sc, struct mpr_command *cm,
    bus_dma_segment_t *segs, int segs_left)
{
        uint32_t                i, sge_dwords, length, offset, entry_len;
        uint32_t                num_entries, buff_len = 0, sges_in_segment;
        uint32_t                page_mask, page_mask_result, *curr_buff;
        uint32_t                *ptr_sgl, *ptr_first_sgl, first_page_offset;
        uint32_t                first_page_data_size, end_residual;
        uint64_t                *msg_phys;
        bus_addr_t              paddr;
        int                     build_native_sgl = 0, first_prp_entry;
        int                     prp_size = PRP_ENTRY_SIZE;
        Mpi25IeeeSgeChain64_t   *main_chain_element = NULL;
        struct mpr_prp_page     *prp_page_info = NULL;

        mpr_dprint(sc, MPR_TRACE, "%s\n", __func__);

        /*
         * Add up the sizes of each segment length to get the total transfer
         * size, which will be checked against the Maximum Data Transfer Size.
         * If the data transfer length exceeds the MDTS for this device, just
         * return 1 so a normal IEEE SGL will be built. F/W will break the I/O
         * up into multiple I/O's. [nvme_mdts = 0 means unlimited]
         */
        for (i = 0; i < segs_left; i++)
                buff_len += htole32(segs[i].ds_len);
        if ((cm->cm_targ->MDTS > 0) && (buff_len > cm->cm_targ->MDTS))
                return 1;

        /* Create page_mask (to get offset within page) */
        page_mask = PAGE_SIZE - 1;

        /*
         * Check if the number of elements exceeds the max number that can be
         * put in the main message frame (H/W can only translate an SGL that
         * is contained entirely in the main message frame).
         */
        sges_in_segment = (sc->reqframesz -
            offsetof(Mpi25SCSIIORequest_t, SGL)) / sizeof(MPI25_SGE_IO_UNION);
        if (segs_left > sges_in_segment)
                build_native_sgl = 1;
        else
        {
                /*
                 * NVMe uses one PRP for each physical page (or part of physical
                 * page).
                 *    if 4 pages or less then IEEE is OK
                 *    if > 5 pages then we need to build a native SGL
                 *    if > 4 and <= 5 pages, then check the physical address of
                 *      the first SG entry, then if this first size in the page
                 *      is >= the residual beyond 4 pages then use IEEE,
                 *      otherwise use native SGL
                 */
                if (buff_len > (PAGE_SIZE * 5))
                        build_native_sgl = 1;
                else if ((buff_len > (PAGE_SIZE * 4)) &&
                    (buff_len <= (PAGE_SIZE * 5)) )
                {
                        msg_phys = (uint64_t *)(uintptr_t)segs[0].ds_addr;
                        first_page_offset =
                            ((uint32_t)(uint64_t)(uintptr_t)msg_phys &
                            page_mask);
                        first_page_data_size = PAGE_SIZE - first_page_offset;
                        end_residual = buff_len % PAGE_SIZE;

                        /*
                         * If offset into first page pushes the end of the data
                         * beyond end of the 5th page, we need the extra PRP
                         * list.
                         */
                        if (first_page_data_size < end_residual)
                                build_native_sgl = 1;

                        /*
                         * Check if first SG entry size is < residual beyond 4
                         * pages.
                         */
                        if (htole32(segs[0].ds_len) <
                            (buff_len - (PAGE_SIZE * 4)))
                                build_native_sgl = 1;
                }
        }

        /* check if native SGL is needed */
        if (!build_native_sgl)
                return 1;

        /*
         * Native SGL is needed.
         * Put a chain element in main message frame that points to the first
         * chain buffer.
         *
         * NOTE:  The ChainOffset field must be 0 when using a chain pointer to
         *        a native SGL.
         */

        /* Set main message chain element pointer */
        main_chain_element = (pMpi25IeeeSgeChain64_t)cm->cm_sge;

        /*
         * For NVMe the chain element needs to be the 2nd SGL entry in the main
         * message.
         */
        main_chain_element = (Mpi25IeeeSgeChain64_t *)
            ((uint8_t *)main_chain_element + sizeof(MPI25_IEEE_SGE_CHAIN64));

        /*
         * For the PRP entries, use the specially allocated buffer of
         * contiguous memory. PRP Page allocation failures should not happen
         * because there should be enough PRP page buffers to account for the
         * possible NVMe QDepth.
         */
        prp_page_info = mpr_alloc_prp_page(sc);
        KASSERT(prp_page_info != NULL, ("%s: There are no PRP Pages left to be "
            "used for building a native NVMe SGL.\n", __func__));
        curr_buff = (uint32_t *)prp_page_info->prp_page;
        msg_phys = (uint64_t *)(uintptr_t)prp_page_info->prp_page_busaddr;

        /*
         * Insert the allocated PRP page into the command's PRP page list. This
         * will be freed when the command is freed.
         */
        TAILQ_INSERT_TAIL(&cm->cm_prp_page_list, prp_page_info, prp_page_link);

        /*
         * Check if we are within 1 entry of a page boundary we don't want our
         * first entry to be a PRP List entry.
         */
        page_mask_result = (uintptr_t)((uint8_t *)curr_buff + prp_size) &
            page_mask;
        if (!page_mask_result) {
                /* Bump up to next page boundary. */
                curr_buff = (uint32_t *)((uint8_t *)curr_buff + prp_size);
                msg_phys = (uint64_t *)((uint8_t *)msg_phys + prp_size);
        }

        /* Fill in the chain element and make it an NVMe segment type. */
        main_chain_element->Address.High =
            htole32((uint32_t)((uint64_t)(uintptr_t)msg_phys >> 32));
        main_chain_element->Address.Low =
            htole32((uint32_t)(uintptr_t)msg_phys);
        main_chain_element->NextChainOffset = 0;
        main_chain_element->Flags = MPI2_IEEE_SGE_FLAGS_CHAIN_ELEMENT |
            MPI2_IEEE_SGE_FLAGS_SYSTEM_ADDR |
            MPI26_IEEE_SGE_FLAGS_NSF_NVME_PRP;

        /* Set SGL pointer to start of contiguous PCIe buffer. */
        ptr_sgl = curr_buff;
        sge_dwords = 2;
        num_entries = 0;

        /*
         * NVMe has a very convoluted PRP format. One PRP is required for each
         * page or partial page. We need to split up OS SG entries if they are
         * longer than one page or cross a page boundary. We also have to insert
         * a PRP list pointer entry as the last entry in each physical page of
         * the PRP list.
         *
         * NOTE: The first PRP "entry" is actually placed in the first SGL entry
         * in the main message in IEEE 64 format. The 2nd entry in the main
         * message is the chain element, and the rest of the PRP entries are
         * built in the contiguous PCIe buffer.
         */
        first_prp_entry = 1;
        ptr_first_sgl = (uint32_t *)cm->cm_sge;

        for (i = 0; i < segs_left; i++) {
                /* Get physical address and length of this SG entry. */
                paddr = segs[i].ds_addr;
                length = segs[i].ds_len;

                /*
                 * Check whether a given SGE buffer lies on a non-PAGED
                 * boundary if this is not the first page. If so, this is not
                 * expected so have FW build the SGL.
                 */
                if ((i != 0) && (((uint32_t)paddr & page_mask) != 0)) {
                        mpr_dprint(sc, MPR_ERROR, "Unaligned SGE while "
                            "building NVMe PRPs, low address is 0x%x\n",
                            (uint32_t)paddr);
                        return 1;
                }

                /* Apart from last SGE, if any other SGE boundary is not page
                 * aligned then it means that hole exists. Existence of hole
                 * leads to data corruption. So fallback to IEEE SGEs.
                 */
                if (i != (segs_left - 1)) {
                        if (((uint32_t)paddr + length) & page_mask) {
                                mpr_dprint(sc, MPR_ERROR, "Unaligned SGE "
                                    "boundary while building NVMe PRPs, low "
                                    "address: 0x%x and length: %u\n",
                                    (uint32_t)paddr, length);
                                return 1;
                        }
                }

                /* Loop while the length is not zero. */
                while (length) {
                        /*
                         * Check if we need to put a list pointer here if we are
                         * at page boundary - prp_size.
                         */
                        page_mask_result = (uintptr_t)((uint8_t *)ptr_sgl +
                            prp_size) & page_mask;
                        if (!page_mask_result) {
                                /*
                                 * Need to put a PRP list pointer here.
                                 */
                                msg_phys = (uint64_t *)((uint8_t *)msg_phys +
                                    prp_size);
                                *ptr_sgl = htole32((uintptr_t)msg_phys);
                                *(ptr_sgl+1) = htole32((uint64_t)(uintptr_t)
                                    msg_phys >> 32);
                                ptr_sgl += sge_dwords;
                                num_entries++;
                        }

                        /* Need to handle if entry will be part of a page. */
                        offset = (uint32_t)paddr & page_mask;
                        entry_len = PAGE_SIZE - offset;
                        if (first_prp_entry) {
                                /*
                                 * Put IEEE entry in first SGE in main message.
                                 * (Simple element, System addr, not end of
                                 * list.)
                                 */
                                *ptr_first_sgl = htole32((uint32_t)paddr);
                                *(ptr_first_sgl + 1) =
                                    htole32((uint32_t)((uint64_t)paddr >> 32));
                                *(ptr_first_sgl + 2) = htole32(entry_len);
                                *(ptr_first_sgl + 3) = 0;

                                /* No longer the first PRP entry. */
                                first_prp_entry = 0;
                        } else {
                                /* Put entry in list. */
                                *ptr_sgl = htole32((uint32_t)paddr);
                                *(ptr_sgl + 1) =
                                    htole32((uint32_t)((uint64_t)paddr >> 32));

                                /* Bump ptr_sgl, msg_phys, and num_entries. */
                                ptr_sgl += sge_dwords;
                                msg_phys = (uint64_t *)((uint8_t *)msg_phys +
                                    prp_size);
                                num_entries++;
                        }

                        /* Bump the phys address by the entry_len. */
                        paddr += entry_len;

                        /* Decrement length accounting for last partial page. */
                        if (entry_len > length)
                                length = 0;
                        else
                                length -= entry_len;
                }
        }

        /* Set chain element Length. */
        main_chain_element->Length = htole32(num_entries * prp_size);

        /* Return 0, indicating we built a native SGL. */
        return 0;
}

/*
 * Add a chain element as the next SGE for the specified command.
 * Reset cm_sge and cm_sgesize to indicate all the available space. Chains are
 * only required for IEEE commands.  Therefore there is no code for commands
 * that have the MPR_CM_FLAGS_SGE_SIMPLE flag set (and those commands
 * shouldn't be requesting chains).
 */
static int
mpr_add_chain(struct mpr_command *cm, int segsleft)
{
        struct mpr_softc *sc = cm->cm_sc;
        MPI2_REQUEST_HEADER *req;
        MPI25_IEEE_SGE_CHAIN64 *ieee_sgc;
        struct mpr_chain *chain;
        int sgc_size, current_segs, rem_segs, segs_per_frame;
        uint8_t next_chain_offset = 0;

        /*
         * Fail if a command is requesting a chain for SIMPLE SGE's.  For SAS3
         * only IEEE commands should be requesting chains.  Return some error
         * code other than 0.
         */
        if (cm->cm_flags & MPR_CM_FLAGS_SGE_SIMPLE) {
                mpr_dprint(sc, MPR_ERROR, "A chain element cannot be added to "
                    "an MPI SGL.\n");
                return(ENOBUFS);
        }

        sgc_size = sizeof(MPI25_IEEE_SGE_CHAIN64);
        if (cm->cm_sglsize < sgc_size)
                panic("MPR: Need SGE Error Code\n");

        chain = mpr_alloc_chain(cm->cm_sc);
        if (chain == NULL)
                return (ENOBUFS);

        /*
         * Note: a double-linked list is used to make it easier to walk for
         * debugging.
         */
        TAILQ_INSERT_TAIL(&cm->cm_chain_list, chain, chain_link);

        /*
         * Need to know if the number of frames left is more than 1 or not.  If
         * more than 1 frame is required, NextChainOffset will need to be set,
         * which will just be the last segment of the frame.
         */
        rem_segs = 0;
        if (cm->cm_sglsize < (sgc_size * segsleft)) {
                /*
                 * rem_segs is the number of segements remaining after the
                 * segments that will go into the current frame.  Since it is
                 * known that at least one more frame is required, account for
                 * the chain element.  To know if more than one more frame is
                 * required, just check if there will be a remainder after using
                 * the current frame (with this chain) and the next frame.  If
                 * so the NextChainOffset must be the last element of the next
                 * frame.
                 */
                current_segs = (cm->cm_sglsize / sgc_size) - 1;
                rem_segs = segsleft - current_segs;
                segs_per_frame = sc->chain_frame_size / sgc_size;
                if (rem_segs > segs_per_frame) {
                        next_chain_offset = segs_per_frame - 1;
                }
        }
        ieee_sgc = &((MPI25_SGE_IO_UNION *)cm->cm_sge)->IeeeChain;
        ieee_sgc->Length = next_chain_offset ?
            htole32((uint32_t)sc->chain_frame_size) :
            htole32((uint32_t)rem_segs * (uint32_t)sgc_size);
        ieee_sgc->NextChainOffset = next_chain_offset;
        ieee_sgc->Flags = (MPI2_IEEE_SGE_FLAGS_CHAIN_ELEMENT |
            MPI2_IEEE_SGE_FLAGS_SYSTEM_ADDR);
        ieee_sgc->Address.Low = htole32(chain->chain_busaddr);
        ieee_sgc->Address.High = htole32(chain->chain_busaddr >> 32);
        cm->cm_sge = &((MPI25_SGE_IO_UNION *)chain->chain)->IeeeSimple;
        req = (MPI2_REQUEST_HEADER *)cm->cm_req;
        req->ChainOffset = (sc->chain_frame_size - sgc_size) >> 4;

        cm->cm_sglsize = sc->chain_frame_size;
        return (0);
}

/*
 * Add one scatter-gather element to the scatter-gather list for a command.
 * Maintain cm_sglsize and cm_sge as the remaining size and pointer to the
 * next SGE to fill in, respectively.  In Gen3, the MPI SGL does not have a
 * chain, so don't consider any chain additions.
 */
int
mpr_push_sge(struct mpr_command *cm, MPI2_SGE_SIMPLE64 *sge, size_t len,
    int segsleft)
{
        uint32_t saved_buf_len, saved_address_low, saved_address_high;
        u32 sge_flags;

        /*
         * case 1: >=1 more segment, no room for anything (error)
         * case 2: 1 more segment and enough room for it
         */

        if (cm->cm_sglsize < (segsleft * sizeof(MPI2_SGE_SIMPLE64))) {
                mpr_dprint(cm->cm_sc, MPR_ERROR,
                    "%s: warning: Not enough room for MPI SGL in frame.\n",
                    __func__);
                return(ENOBUFS);
        }

        KASSERT(segsleft == 1,
            ("segsleft cannot be more than 1 for an MPI SGL; segsleft = %d\n",
            segsleft));

        /*
         * There is one more segment left to add for the MPI SGL and there is
         * enough room in the frame to add it.  This is the normal case because
         * MPI SGL's don't have chains, otherwise something is wrong.
         *
         * If this is a bi-directional request, need to account for that
         * here.  Save the pre-filled sge values.  These will be used
         * either for the 2nd SGL or for a single direction SGL.  If
         * cm_out_len is non-zero, this is a bi-directional request, so
         * fill in the OUT SGL first, then the IN SGL, otherwise just
         * fill in the IN SGL.  Note that at this time, when filling in
         * 2 SGL's for a bi-directional request, they both use the same
         * DMA buffer (same cm command).
         */
        saved_buf_len = sge->FlagsLength & 0x00FFFFFF;
        saved_address_low = sge->Address.Low;
        saved_address_high = sge->Address.High;
        if (cm->cm_out_len) {
                sge->FlagsLength = cm->cm_out_len |
                    ((uint32_t)(MPI2_SGE_FLAGS_SIMPLE_ELEMENT |
                    MPI2_SGE_FLAGS_END_OF_BUFFER |
                    MPI2_SGE_FLAGS_HOST_TO_IOC |
                    MPI2_SGE_FLAGS_64_BIT_ADDRESSING) <<
                    MPI2_SGE_FLAGS_SHIFT);
                cm->cm_sglsize -= len;
                /* Endian Safe code */
                sge_flags = sge->FlagsLength;
                sge->FlagsLength = htole32(sge_flags);
                sge->Address.High = htole32(sge->Address.High); 
                sge->Address.Low = htole32(sge->Address.Low);
                bcopy(sge, cm->cm_sge, len);
                cm->cm_sge = (MPI2_SGE_IO_UNION *)((uintptr_t)cm->cm_sge + len);
        }
        sge->FlagsLength = saved_buf_len |
            ((uint32_t)(MPI2_SGE_FLAGS_SIMPLE_ELEMENT |
            MPI2_SGE_FLAGS_END_OF_BUFFER |
            MPI2_SGE_FLAGS_LAST_ELEMENT |
            MPI2_SGE_FLAGS_END_OF_LIST |
            MPI2_SGE_FLAGS_64_BIT_ADDRESSING) <<
            MPI2_SGE_FLAGS_SHIFT);
        if (cm->cm_flags & MPR_CM_FLAGS_DATAIN) {
                sge->FlagsLength |=
                    ((uint32_t)(MPI2_SGE_FLAGS_IOC_TO_HOST) <<
                    MPI2_SGE_FLAGS_SHIFT);
        } else {
                sge->FlagsLength |=
                    ((uint32_t)(MPI2_SGE_FLAGS_HOST_TO_IOC) <<
                    MPI2_SGE_FLAGS_SHIFT);
        }
        sge->Address.Low = saved_address_low;
        sge->Address.High = saved_address_high;

        cm->cm_sglsize -= len;
        /* Endian Safe code */
        sge_flags = sge->FlagsLength;
        sge->FlagsLength = htole32(sge_flags);
        sge->Address.High = htole32(sge->Address.High); 
        sge->Address.Low = htole32(sge->Address.Low);
        bcopy(sge, cm->cm_sge, len);
        cm->cm_sge = (MPI2_SGE_IO_UNION *)((uintptr_t)cm->cm_sge + len);
        return (0);
}

/*
 * Add one IEEE scatter-gather element (chain or simple) to the IEEE scatter-
 * gather list for a command.  Maintain cm_sglsize and cm_sge as the
 * remaining size and pointer to the next SGE to fill in, respectively.
 */
int
mpr_push_ieee_sge(struct mpr_command *cm, void *sgep, int segsleft)
{
        MPI2_IEEE_SGE_SIMPLE64 *sge = sgep;
        int error, ieee_sge_size = sizeof(MPI25_SGE_IO_UNION);
        uint32_t saved_buf_len, saved_address_low, saved_address_high;
        uint32_t sge_length;

        /*
         * case 1: No room for chain or segment (error).
         * case 2: Two or more segments left but only room for chain.
         * case 3: Last segment and room for it, so set flags.
         */

        /*
         * There should be room for at least one element, or there is a big
         * problem.
         */
        if (cm->cm_sglsize < ieee_sge_size)
                panic("MPR: Need SGE Error Code\n");

        if ((segsleft >= 2) && (cm->cm_sglsize < (ieee_sge_size * 2))) {
                if ((error = mpr_add_chain(cm, segsleft)) != 0)
                        return (error);
        }

        if (segsleft == 1) {
                /*
                 * If this is a bi-directional request, need to account for that
                 * here.  Save the pre-filled sge values.  These will be used
                 * either for the 2nd SGL or for a single direction SGL.  If
                 * cm_out_len is non-zero, this is a bi-directional request, so
                 * fill in the OUT SGL first, then the IN SGL, otherwise just
                 * fill in the IN SGL.  Note that at this time, when filling in
                 * 2 SGL's for a bi-directional request, they both use the same
                 * DMA buffer (same cm command).
                 */
                saved_buf_len = sge->Length;
                saved_address_low = sge->Address.Low;
                saved_address_high = sge->Address.High;
                if (cm->cm_out_len) {
                        sge->Length = cm->cm_out_len;
                        sge->Flags = (MPI2_IEEE_SGE_FLAGS_SIMPLE_ELEMENT |
                            MPI2_IEEE_SGE_FLAGS_SYSTEM_ADDR);
                        cm->cm_sglsize -= ieee_sge_size;
                        /* Endian Safe code */
                        sge_length = sge->Length;
                        sge->Length = htole32(sge_length);
                        sge->Address.High = htole32(sge->Address.High); 
                        sge->Address.Low = htole32(sge->Address.Low);
                        bcopy(sgep, cm->cm_sge, ieee_sge_size);
                        cm->cm_sge =
                            (MPI25_SGE_IO_UNION *)((uintptr_t)cm->cm_sge +
                            ieee_sge_size);
                }
                sge->Length = saved_buf_len;
                sge->Flags = (MPI2_IEEE_SGE_FLAGS_SIMPLE_ELEMENT |
                    MPI2_IEEE_SGE_FLAGS_SYSTEM_ADDR |
                    MPI25_IEEE_SGE_FLAGS_END_OF_LIST);
                sge->Address.Low = saved_address_low;
                sge->Address.High = saved_address_high;
        }

        cm->cm_sglsize -= ieee_sge_size;
        /* Endian Safe code */
        sge_length = sge->Length;
        sge->Length = htole32(sge_length);
        sge->Address.High = htole32(sge->Address.High); 
        sge->Address.Low = htole32(sge->Address.Low);
        bcopy(sgep, cm->cm_sge, ieee_sge_size);
        cm->cm_sge = (MPI25_SGE_IO_UNION *)((uintptr_t)cm->cm_sge +
            ieee_sge_size);
        return (0);
}

/*
 * Add one dma segment to the scatter-gather list for a command.
 */
int
mpr_add_dmaseg(struct mpr_command *cm, vm_paddr_t pa, size_t len, u_int flags,
    int segsleft)
{
        MPI2_SGE_SIMPLE64 sge;
        MPI2_IEEE_SGE_SIMPLE64 ieee_sge;

        if (!(cm->cm_flags & MPR_CM_FLAGS_SGE_SIMPLE)) {
                ieee_sge.Flags = (MPI2_IEEE_SGE_FLAGS_SIMPLE_ELEMENT |
                    MPI2_IEEE_SGE_FLAGS_SYSTEM_ADDR);
                ieee_sge.Length = len;
                mpr_from_u64(pa, &ieee_sge.Address);

                return (mpr_push_ieee_sge(cm, &ieee_sge, segsleft));
        } else {
                /*
                 * This driver always uses 64-bit address elements for
                 * simplicity.
                 */
                flags |= MPI2_SGE_FLAGS_SIMPLE_ELEMENT |
                    MPI2_SGE_FLAGS_64_BIT_ADDRESSING;
                /* Set Endian safe macro in mpr_push_sge */
                sge.FlagsLength = len | (flags << MPI2_SGE_FLAGS_SHIFT);
                mpr_from_u64(pa, &sge.Address);

                return (mpr_push_sge(cm, &sge, sizeof sge, segsleft));
        }
}

static void
mpr_data_cb(void *arg, bus_dma_segment_t *segs, int nsegs, int error)
{
        struct mpr_softc *sc;
        struct mpr_command *cm;
        u_int i, dir, sflags;

        cm = (struct mpr_command *)arg;
        sc = cm->cm_sc;

        /*
         * In this case, just print out a warning and let the chip tell the
         * user they did the wrong thing.
         */
        if ((cm->cm_max_segs != 0) && (nsegs > cm->cm_max_segs)) {
                mpr_dprint(sc, MPR_ERROR, "%s: warning: busdma returned %d "
                    "segments, more than the %d allowed\n", __func__, nsegs,
                    cm->cm_max_segs);
        }

        /*
         * Set up DMA direction flags.  Bi-directional requests are also handled
         * here.  In that case, both direction flags will be set.
         */
        sflags = 0;
        if (cm->cm_flags & MPR_CM_FLAGS_SMP_PASS) {
                /*
                 * We have to add a special case for SMP passthrough, there
                 * is no easy way to generically handle it.  The first
                 * S/G element is used for the command (therefore the
                 * direction bit needs to be set).  The second one is used
                 * for the reply.  We'll leave it to the caller to make
                 * sure we only have two buffers.
                 */
                /*
                 * Even though the busdma man page says it doesn't make
                 * sense to have both direction flags, it does in this case.
                 * We have one s/g element being accessed in each direction.
                 */
                dir = BUS_DMASYNC_PREWRITE | BUS_DMASYNC_PREREAD;

                /*
                 * Set the direction flag on the first buffer in the SMP
                 * passthrough request.  We'll clear it for the second one.
                 */
                sflags |= MPI2_SGE_FLAGS_DIRECTION |
                          MPI2_SGE_FLAGS_END_OF_BUFFER;
        } else if (cm->cm_flags & MPR_CM_FLAGS_DATAOUT) {
                sflags |= MPI2_SGE_FLAGS_HOST_TO_IOC;
                dir = BUS_DMASYNC_PREWRITE;
        } else
                dir = BUS_DMASYNC_PREREAD;

        /* Check if a native SG list is needed for an NVMe PCIe device. */
        if (cm->cm_targ && cm->cm_targ->is_nvme &&
            mpr_check_pcie_native_sgl(sc, cm, segs, nsegs) == 0) {
                /* A native SG list was built, skip to end. */
                goto out;
        }

        for (i = 0; i < nsegs; i++) {
                if ((cm->cm_flags & MPR_CM_FLAGS_SMP_PASS) && (i != 0)) {
                        sflags &= ~MPI2_SGE_FLAGS_DIRECTION;
                }
                error = mpr_add_dmaseg(cm, segs[i].ds_addr, segs[i].ds_len,
                    sflags, nsegs - i);
                if (error != 0) {
                        /* Resource shortage, roll back! */
                        if (ratecheck(&sc->lastfail, &mpr_chainfail_interval))
                                mpr_dprint(sc, MPR_INFO, "Out of chain frames, "
                                    "consider increasing hw.mpr.max_chains.\n");
                        cm->cm_flags |= MPR_CM_FLAGS_CHAIN_FAILED;
                        mpr_complete_command(sc, cm);
                        return;
                }
        }

out:
        bus_dmamap_sync(sc->buffer_dmat, cm->cm_dmamap, dir);
        mpr_enqueue_request(sc, cm);

        return;
}

static void
mpr_data_cb2(void *arg, bus_dma_segment_t *segs, int nsegs, bus_size_t mapsize,
             int error)
{
        mpr_data_cb(arg, segs, nsegs, error);
}

/*
 * This is the routine to enqueue commands ansynchronously.
 * Note that the only error path here is from bus_dmamap_load(), which can
 * return EINPROGRESS if it is waiting for resources.  Other than this, it's
 * assumed that if you have a command in-hand, then you have enough credits
 * to use it.
 */
int
mpr_map_command(struct mpr_softc *sc, struct mpr_command *cm)
{
        int error = 0;

        if (cm->cm_flags & MPR_CM_FLAGS_USE_UIO) {
                error = bus_dmamap_load_uio(sc->buffer_dmat, cm->cm_dmamap,
                    &cm->cm_uio, mpr_data_cb2, cm, 0);
        } else if (cm->cm_flags & MPR_CM_FLAGS_USE_CCB) {
                error = bus_dmamap_load_ccb(sc->buffer_dmat, cm->cm_dmamap,
                    cm->cm_data, mpr_data_cb, cm, 0);
        } else if ((cm->cm_data != NULL) && (cm->cm_length != 0)) {
                error = bus_dmamap_load(sc->buffer_dmat, cm->cm_dmamap,
                    cm->cm_data, cm->cm_length, mpr_data_cb, cm, 0);
        } else {
                /* Add a zero-length element as needed */
                if (cm->cm_sge != NULL)
                        mpr_add_dmaseg(cm, 0, 0, 0, 1);
                mpr_enqueue_request(sc, cm);
        }

        return (error);
}

/*
 * This is the routine to enqueue commands synchronously.  An error of
 * EINPROGRESS from mpr_map_command() is ignored since the command will
 * be executed and enqueued automatically.  Other errors come from msleep().
 */
int
mpr_wait_command(struct mpr_softc *sc, struct mpr_command **cmp, int timeout,
    int sleep_flag)
{
        int error, rc;
        struct timeval cur_time, start_time;
        struct mpr_command *cm = *cmp;

        if (sc->mpr_flags & MPR_FLAGS_DIAGRESET) 
                return  EBUSY;

        cm->cm_complete = NULL;
        cm->cm_flags |= (MPR_CM_FLAGS_WAKEUP + MPR_CM_FLAGS_POLLED);
        error = mpr_map_command(sc, cm);
        if ((error != 0) && (error != EINPROGRESS))
                return (error);

        // Check for context and wait for 50 mSec at a time until time has
        // expired or the command has finished.  If msleep can't be used, need
        // to poll.
#if __FreeBSD_version >= 1000029
        if (curthread->td_no_sleeping)
#else //__FreeBSD_version < 1000029
        if (curthread->td_pflags & TDP_NOSLEEPING)
#endif //__FreeBSD_version >= 1000029
                sleep_flag = NO_SLEEP;
        getmicrouptime(&start_time);
        if (mtx_owned(&sc->mpr_mtx) && sleep_flag == CAN_SLEEP) {
                error = msleep(cm, &sc->mpr_mtx, 0, "mprwait", timeout*hz);
                if (error == EWOULDBLOCK) {
                        /*
                         * Record the actual elapsed time in the case of a
                         * timeout for the message below.
                         */
                        getmicrouptime(&cur_time);
                        timevalsub(&cur_time, &start_time);
                }
        } else {
                while ((cm->cm_flags & MPR_CM_FLAGS_COMPLETE) == 0) {
                        mpr_intr_locked(sc);
                        if (sleep_flag == CAN_SLEEP)
                                pause("mprwait", hz/20);
                        else
                                DELAY(50000);
                
                        getmicrouptime(&cur_time);
                        timevalsub(&cur_time, &start_time);
                        if (cur_time.tv_sec > timeout) {
                                error = EWOULDBLOCK;
                                break;
                        }
                }
        }

        if (error == EWOULDBLOCK) {
                if (cm->cm_timeout_handler == NULL) {
                        mpr_dprint(sc, MPR_FAULT, "Calling Reinit from %s, timeout=%d,"
                            " elapsed=%jd\n", __func__, timeout,
                            (intmax_t)cur_time.tv_sec);
                        rc = mpr_reinit(sc);
                        mpr_dprint(sc, MPR_FAULT, "Reinit %s\n", (rc == 0) ? "success" :
                            "failed");
                } else
                        cm->cm_timeout_handler(sc, cm);
                if (sc->mpr_flags & MPR_FLAGS_REALLOCATED) {
                        /*
                         * Tell the caller that we freed the command in a
                         * reinit.
                         */
                        *cmp = NULL;
                }
                error = ETIMEDOUT;
        }
        return (error);
}

/*
 * This is the routine to enqueue a command synchonously and poll for
 * completion.  Its use should be rare.
 */
int
mpr_request_polled(struct mpr_softc *sc, struct mpr_command **cmp)
{
        int error, rc;
        struct timeval cur_time, start_time;
        struct mpr_command *cm = *cmp;

        error = 0;

        cm->cm_flags |= MPR_CM_FLAGS_POLLED;
        cm->cm_complete = NULL;
        mpr_map_command(sc, cm);

        getmicrouptime(&start_time);
        while ((cm->cm_flags & MPR_CM_FLAGS_COMPLETE) == 0) {
                mpr_intr_locked(sc);

                if (mtx_owned(&sc->mpr_mtx))
                        msleep(&sc->msleep_fake_chan, &sc->mpr_mtx, 0,
                            "mprpoll", hz/20);
                else
                        pause("mprpoll", hz/20);

                /*
                 * Check for real-time timeout and fail if more than 60 seconds.
                 */
                getmicrouptime(&cur_time);
                timevalsub(&cur_time, &start_time);
                if (cur_time.tv_sec > 60) {
                        mpr_dprint(sc, MPR_FAULT, "polling failed\n");
                        error = ETIMEDOUT;
                        break;
                }
        }
        cm->cm_state = MPR_CM_STATE_BUSY;
        if (error) {
                mpr_dprint(sc, MPR_FAULT, "Calling Reinit from %s\n", __func__);
                rc = mpr_reinit(sc);
                mpr_dprint(sc, MPR_FAULT, "Reinit %s\n", (rc == 0) ? "success" :
                    "failed");

                if (sc->mpr_flags & MPR_FLAGS_REALLOCATED) {
                        /*
                         * Tell the caller that we freed the command in a
                         * reinit.
                         */
                        *cmp = NULL;
                }
        }
        return (error);
}

/*
 * The MPT driver had a verbose interface for config pages.  In this driver,
 * reduce it to much simpler terms, similar to the Linux driver.
 */
int
mpr_read_config_page(struct mpr_softc *sc, struct mpr_config_params *params)
{
        MPI2_CONFIG_REQUEST *req;
        struct mpr_command *cm;
        int error;

        if (sc->mpr_flags & MPR_FLAGS_BUSY) {
                return (EBUSY);
        }

        cm = mpr_alloc_command(sc);
        if (cm == NULL) {
                return (EBUSY);
        }

        req = (MPI2_CONFIG_REQUEST *)cm->cm_req;
        req->Function = MPI2_FUNCTION_CONFIG;
        req->Action = params->action;
        req->SGLFlags = 0;
        req->ChainOffset = 0;
        req->PageAddress = params->page_address;
        if (params->hdr.Struct.PageType == MPI2_CONFIG_PAGETYPE_EXTENDED) {
                MPI2_CONFIG_EXTENDED_PAGE_HEADER *hdr;

                hdr = &params->hdr.Ext;
                req->ExtPageType = hdr->ExtPageType;
                req->ExtPageLength = hdr->ExtPageLength;
                req->Header.PageType = MPI2_CONFIG_PAGETYPE_EXTENDED;
                req->Header.PageLength = 0; /* Must be set to zero */
                req->Header.PageNumber = hdr->PageNumber;
                req->Header.PageVersion = hdr->PageVersion;
        } else {
                MPI2_CONFIG_PAGE_HEADER *hdr;

                hdr = &params->hdr.Struct;
                req->Header.PageType = hdr->PageType;
                req->Header.PageNumber = hdr->PageNumber;
                req->Header.PageLength = hdr->PageLength;
                req->Header.PageVersion = hdr->PageVersion;
        }

        cm->cm_data = params->buffer;
        cm->cm_length = params->length;
        if (cm->cm_data != NULL) {
                cm->cm_sge = &req->PageBufferSGE;
                cm->cm_sglsize = sizeof(MPI2_SGE_IO_UNION);
                cm->cm_flags = MPR_CM_FLAGS_SGE_SIMPLE | MPR_CM_FLAGS_DATAIN;
        } else
                cm->cm_sge = NULL;
        cm->cm_desc.Default.RequestFlags = MPI2_REQ_DESCRIPT_FLAGS_DEFAULT_TYPE;

        cm->cm_complete_data = params;
        if (params->callback != NULL) {
                cm->cm_complete = mpr_config_complete;
                return (mpr_map_command(sc, cm));
        } else {
                error = mpr_wait_command(sc, &cm, 0, CAN_SLEEP);
                if (error) {
                        mpr_dprint(sc, MPR_FAULT,
                            "Error %d reading config page\n", error);
                        if (cm != NULL)
                                mpr_free_command(sc, cm);
                        return (error);
                }
                mpr_config_complete(sc, cm);
        }

        return (0);
}

int
mpr_write_config_page(struct mpr_softc *sc, struct mpr_config_params *params)
{
        return (EINVAL);
}

static void
mpr_config_complete(struct mpr_softc *sc, struct mpr_command *cm)
{
        MPI2_CONFIG_REPLY *reply;
        struct mpr_config_params *params;

        MPR_FUNCTRACE(sc);
        params = cm->cm_complete_data;

        if (cm->cm_data != NULL) {
                bus_dmamap_sync(sc->buffer_dmat, cm->cm_dmamap,
                    BUS_DMASYNC_POSTREAD);
                bus_dmamap_unload(sc->buffer_dmat, cm->cm_dmamap);
        }

        /*
         * XXX KDM need to do more error recovery?  This results in the
         * device in question not getting probed.
         */
        if ((cm->cm_flags & MPR_CM_FLAGS_ERROR_MASK) != 0) {
                params->status = MPI2_IOCSTATUS_BUSY;
                goto done;
        }

        reply = (MPI2_CONFIG_REPLY *)cm->cm_reply;
        if (reply == NULL) {
                params->status = MPI2_IOCSTATUS_BUSY;
                goto done;
        }
        params->status = reply->IOCStatus;
        if (params->hdr.Struct.PageType == MPI2_CONFIG_PAGETYPE_EXTENDED) {
                params->hdr.Ext.ExtPageType = reply->ExtPageType;
                params->hdr.Ext.ExtPageLength = reply->ExtPageLength;
                params->hdr.Ext.PageType = reply->Header.PageType;
                params->hdr.Ext.PageNumber = reply->Header.PageNumber;
                params->hdr.Ext.PageVersion = reply->Header.PageVersion;
        } else {
                params->hdr.Struct.PageType = reply->Header.PageType;
                params->hdr.Struct.PageNumber = reply->Header.PageNumber;
                params->hdr.Struct.PageLength = reply->Header.PageLength;
                params->hdr.Struct.PageVersion = reply->Header.PageVersion;
        }

done:
        mpr_free_command(sc, cm);
        if (params->callback != NULL)
                params->callback(sc, params);

        return;
}