- Copy stable/10 (r259064) to releng/10.0 as part of the

[FreeBSD/releng/10.0.git] / sys / dev / usb / input / atp.c

/*-
 * Copyright (c) 2009 Rohit Grover
 * 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.
 */

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

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/module.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/bus.h>
#include <sys/conf.h>
#include <sys/fcntl.h>
#include <sys/file.h>
#include <sys/selinfo.h>
#include <sys/poll.h>
#include <sys/sysctl.h>
#include <sys/uio.h>

#include <dev/usb/usb.h>
#include <dev/usb/usbdi.h>
#include <dev/usb/usbdi_util.h>
#include <dev/usb/usbhid.h>
#include "usbdevs.h"

#define USB_DEBUG_VAR atp_debug
#include <dev/usb/usb_debug.h>

#include <sys/mouse.h>

#define ATP_DRIVER_NAME "atp"

/*
 * Driver specific options: the following options may be set by
 * `options' statements in the kernel configuration file.
 */

/* The multiplier used to translate sensor reported positions to mickeys. */
#ifndef ATP_SCALE_FACTOR
#define ATP_SCALE_FACTOR 48
#endif

/*
 * This is the age (in microseconds) beyond which a touch is
 * considered to be a slide; and therefore a tap event isn't registered.
 */
#ifndef ATP_TOUCH_TIMEOUT
#define ATP_TOUCH_TIMEOUT 125000
#endif

/*
 * A double-tap followed by a single-finger slide is treated as a
 * special gesture. The driver responds to this gesture by assuming a
 * virtual button-press for the lifetime of the slide. The following
 * threshold is the maximum time gap (in microseconds) between the two
 * tap events preceding the slide for such a gesture.
 */
#ifndef ATP_DOUBLE_TAP_N_DRAG_THRESHOLD
#define ATP_DOUBLE_TAP_N_DRAG_THRESHOLD 200000
#endif

/*
 * The device provides us only with pressure readings from an array of
 * X and Y sensors; for our algorithms, we need to interpret groups
 * (typically pairs) of X and Y readings as being related to a single
 * finger stroke. We can relate X and Y readings based on their times
 * of incidence. The coincidence window should be at least 10000us
 * since it is used against values from getmicrotime(), which has a
 * precision of around 10ms.
 */
#ifndef ATP_COINCIDENCE_THRESHOLD
#define ATP_COINCIDENCE_THRESHOLD  40000 /* unit: microseconds */
#if ATP_COINCIDENCE_THRESHOLD > 100000
#error "ATP_COINCIDENCE_THRESHOLD too large"
#endif
#endif /* #ifndef ATP_COINCIDENCE_THRESHOLD */

/*
 * The wait duration (in microseconds) after losing a touch contact
 * before zombied strokes are reaped and turned into button events.
 */
#define ATP_ZOMBIE_STROKE_REAP_WINDOW   50000
#if ATP_ZOMBIE_STROKE_REAP_WINDOW > 100000
#error "ATP_ZOMBIE_STROKE_REAP_WINDOW too large"
#endif

/* end of driver specific options */


/* Tunables */
static SYSCTL_NODE(_hw_usb, OID_AUTO, atp, CTLFLAG_RW, 0, "USB atp");

#ifdef USB_DEBUG
enum atp_log_level {
        ATP_LLEVEL_DISABLED = 0,
        ATP_LLEVEL_ERROR,
        ATP_LLEVEL_DEBUG,       /* for troubleshooting */
        ATP_LLEVEL_INFO,        /* for diagnostics */
};
static int atp_debug = ATP_LLEVEL_ERROR; /* the default is to only log errors */
SYSCTL_INT(_hw_usb_atp, OID_AUTO, debug, CTLFLAG_RW,
    &atp_debug, ATP_LLEVEL_ERROR, "ATP debug level");
#endif /* USB_DEBUG */

static u_int atp_touch_timeout = ATP_TOUCH_TIMEOUT;
SYSCTL_UINT(_hw_usb_atp, OID_AUTO, touch_timeout, CTLFLAG_RW,
    &atp_touch_timeout, 125000, "age threshold (in micros) for a touch");

static u_int atp_double_tap_threshold = ATP_DOUBLE_TAP_N_DRAG_THRESHOLD;
SYSCTL_UINT(_hw_usb_atp, OID_AUTO, double_tap_threshold, CTLFLAG_RW,
    &atp_double_tap_threshold, ATP_DOUBLE_TAP_N_DRAG_THRESHOLD,
    "maximum time (in micros) between a double-tap");

static u_int atp_mickeys_scale_factor = ATP_SCALE_FACTOR;
static int atp_sysctl_scale_factor_handler(SYSCTL_HANDLER_ARGS);
SYSCTL_PROC(_hw_usb_atp, OID_AUTO, scale_factor, CTLTYPE_UINT | CTLFLAG_RW,
    &atp_mickeys_scale_factor, sizeof(atp_mickeys_scale_factor),
    atp_sysctl_scale_factor_handler, "IU", "movement scale factor");

static u_int atp_small_movement_threshold = ATP_SCALE_FACTOR >> 3;
SYSCTL_UINT(_hw_usb_atp, OID_AUTO, small_movement, CTLFLAG_RW,
    &atp_small_movement_threshold, ATP_SCALE_FACTOR >> 3,
    "the small movement black-hole for filtering noise");
/*
 * The movement threshold for a stroke; this is the maximum difference
 * in position which will be resolved as a continuation of a stroke
 * component.
 */
static u_int atp_max_delta_mickeys = ((3 * ATP_SCALE_FACTOR) >> 1);
SYSCTL_UINT(_hw_usb_atp, OID_AUTO, max_delta_mickeys, CTLFLAG_RW,
    &atp_max_delta_mickeys, ((3 * ATP_SCALE_FACTOR) >> 1),
    "max. mickeys-delta which will match against an existing stroke");
/*
 * Strokes which accumulate at least this amount of absolute movement
 * from the aggregate of their components are considered as
 * slides. Unit: mickeys.
 */
static u_int atp_slide_min_movement = (ATP_SCALE_FACTOR >> 3);
SYSCTL_UINT(_hw_usb_atp, OID_AUTO, slide_min_movement, CTLFLAG_RW,
    &atp_slide_min_movement, (ATP_SCALE_FACTOR >> 3),
    "strokes with at least this amt. of movement are considered slides");

/*
 * The minimum age of a stroke for it to be considered mature; this
 * helps filter movements (noise) from immature strokes. Units: interrupts.
 */
static u_int atp_stroke_maturity_threshold = 2;
SYSCTL_UINT(_hw_usb_atp, OID_AUTO, stroke_maturity_threshold, CTLFLAG_RW,
    &atp_stroke_maturity_threshold, 2,
    "the minimum age of a stroke for it to be considered mature");

/* Accept pressure readings from sensors only if above this value. */
static u_int atp_sensor_noise_threshold = 2;
SYSCTL_UINT(_hw_usb_atp, OID_AUTO, sensor_noise_threshold, CTLFLAG_RW,
    &atp_sensor_noise_threshold, 2,
    "accept pressure readings from sensors only if above this value");

/* Ignore pressure spans with cumulative press. below this value. */
static u_int atp_pspan_min_cum_pressure = 10;
SYSCTL_UINT(_hw_usb_atp, OID_AUTO, pspan_min_cum_pressure, CTLFLAG_RW,
    &atp_pspan_min_cum_pressure, 10,
    "ignore pressure spans with cumulative press. below this value");

/* Maximum allowed width for pressure-spans.*/
static u_int atp_pspan_max_width = 4;
SYSCTL_UINT(_hw_usb_atp, OID_AUTO, pspan_max_width, CTLFLAG_RW,
    &atp_pspan_max_width, 4,
    "maximum allowed width (in sensors) for pressure-spans");

/* We support three payload protocols */
typedef enum {
        ATP_PROT_GEYSER1,
        ATP_PROT_GEYSER2,
        ATP_PROT_GEYSER3,
} atp_protocol;

/* Define the various flavours of devices supported by this driver. */
enum {
        ATP_DEV_PARAMS_0,
        ATP_DEV_PARAMS_PBOOK,
        ATP_DEV_PARAMS_PBOOK_15A,
        ATP_DEV_PARAMS_PBOOK_17,
        ATP_N_DEV_PARAMS
};
struct atp_dev_params {
        u_int            data_len;   /* for sensor data */
        u_int            n_xsensors;
        u_int            n_ysensors;
        atp_protocol     prot;
} atp_dev_params[ATP_N_DEV_PARAMS] = {
        [ATP_DEV_PARAMS_0] = {
                .data_len   = 64,
                .n_xsensors = 20,
                .n_ysensors = 10,
                .prot       = ATP_PROT_GEYSER3
        },
        [ATP_DEV_PARAMS_PBOOK] = {
                .data_len   = 81,
                .n_xsensors = 16,
                .n_ysensors = 16,
                .prot       = ATP_PROT_GEYSER1
        },
        [ATP_DEV_PARAMS_PBOOK_15A] = {
                .data_len   = 64,
                .n_xsensors = 15,
                .n_ysensors = 9,
                .prot       = ATP_PROT_GEYSER2
        },
        [ATP_DEV_PARAMS_PBOOK_17] = {
                .data_len   = 81,
                .n_xsensors = 26,
                .n_ysensors = 16,
                .prot       = ATP_PROT_GEYSER1
        },
};

static const STRUCT_USB_HOST_ID atp_devs[] = {
        /* Core Duo MacBook & MacBook Pro */
        { USB_VPI(USB_VENDOR_APPLE, 0x0217, ATP_DEV_PARAMS_0) },
        { USB_VPI(USB_VENDOR_APPLE, 0x0218, ATP_DEV_PARAMS_0) },
        { USB_VPI(USB_VENDOR_APPLE, 0x0219, ATP_DEV_PARAMS_0) },

        /* Core2 Duo MacBook & MacBook Pro */
        { USB_VPI(USB_VENDOR_APPLE, 0x021a, ATP_DEV_PARAMS_0) },
        { USB_VPI(USB_VENDOR_APPLE, 0x021b, ATP_DEV_PARAMS_0) },
        { USB_VPI(USB_VENDOR_APPLE, 0x021c, ATP_DEV_PARAMS_0) },

        /* Core2 Duo MacBook3,1 */
        { USB_VPI(USB_VENDOR_APPLE, 0x0229, ATP_DEV_PARAMS_0) },
        { USB_VPI(USB_VENDOR_APPLE, 0x022a, ATP_DEV_PARAMS_0) },
        { USB_VPI(USB_VENDOR_APPLE, 0x022b, ATP_DEV_PARAMS_0) },

        /* 12 inch PowerBook and iBook */
        { USB_VPI(USB_VENDOR_APPLE, 0x030a, ATP_DEV_PARAMS_PBOOK) },
        { USB_VPI(USB_VENDOR_APPLE, 0x030b, ATP_DEV_PARAMS_PBOOK) },

        /* 15 inch PowerBook */
        { USB_VPI(USB_VENDOR_APPLE, 0x020e, ATP_DEV_PARAMS_PBOOK) },
        { USB_VPI(USB_VENDOR_APPLE, 0x020f, ATP_DEV_PARAMS_PBOOK) },
        { USB_VPI(USB_VENDOR_APPLE, 0x0215, ATP_DEV_PARAMS_PBOOK_15A) },

        /* 17 inch PowerBook */
        { USB_VPI(USB_VENDOR_APPLE, 0x020d, ATP_DEV_PARAMS_PBOOK_17) },

};

/*
 * The following structure captures the state of a pressure span along
 * an axis. Each contact with the touchpad results in separate
 * pressure spans along the two axes.
 */
typedef struct atp_pspan {
        u_int width;   /* in units of sensors */
        u_int cum;     /* cumulative compression (from all sensors) */
        u_int cog;     /* center of gravity */
        u_int loc;     /* location (scaled using the mickeys factor) */
        boolean_t matched; /* to track pspans as they match against strokes. */
} atp_pspan;

typedef enum atp_stroke_type {
        ATP_STROKE_TOUCH,
        ATP_STROKE_SLIDE,
} atp_stroke_type;

#define ATP_MAX_PSPANS_PER_AXIS 3

typedef struct atp_stroke_component {
        /* Fields encapsulating the pressure-span. */
        u_int loc;              /* location (scaled) */
        u_int cum_pressure;     /* cumulative compression */
        u_int max_cum_pressure; /* max cumulative compression */
        boolean_t matched; /*to track components as they match against pspans.*/

        /* Fields containing information about movement. */
        int   delta_mickeys;    /* change in location (un-smoothened movement)*/
        int   pending;          /* cum. of pending short movements */
        int   movement;         /* current smoothened movement */
} atp_stroke_component;

typedef enum atp_axis {
        X = 0,
        Y = 1
} atp_axis;

#define ATP_MAX_STROKES         (2 * ATP_MAX_PSPANS_PER_AXIS)

/*
 * The following structure captures a finger contact with the
 * touchpad. A stroke comprises two p-span components and some state.
 */
typedef struct atp_stroke {
        atp_stroke_type      type;
        struct timeval       ctime; /* create time; for coincident siblings. */
        u_int                age;   /*
                                     * Unit: interrupts; we maintain
                                     * this value in addition to
                                     * 'ctime' in order to avoid the
                                     * expensive call to microtime()
                                     * at every interrupt.
                                     */

        atp_stroke_component components[2];
        u_int                velocity_squared; /*
                                                * Average magnitude (squared)
                                                * of recent velocity.
                                                */
        u_int                cum_movement; /* cum. absolute movement so far */

        uint32_t             flags;  /* the state of this stroke */
#define ATSF_ZOMBIE          0x1
} atp_stroke;

#define ATP_FIFO_BUF_SIZE        8 /* bytes */
#define ATP_FIFO_QUEUE_MAXLEN   50 /* units */

enum {
        ATP_INTR_DT,
        ATP_RESET,
        ATP_N_TRANSFER,
};

struct atp_softc {
        device_t               sc_dev;
        struct usb_device     *sc_usb_device;
#define MODE_LENGTH 8
        char                   sc_mode_bytes[MODE_LENGTH]; /* device mode */
        struct mtx             sc_mutex; /* for synchronization */
        struct usb_xfer       *sc_xfer[ATP_N_TRANSFER];
        struct usb_fifo_sc     sc_fifo;

        struct atp_dev_params *sc_params;

        mousehw_t              sc_hw;
        mousemode_t            sc_mode;
        u_int                  sc_pollrate;
        mousestatus_t          sc_status;
        u_int                  sc_state;
#define ATP_ENABLED            0x01
#define ATP_ZOMBIES_EXIST      0x02
#define ATP_DOUBLE_TAP_DRAG    0x04
#define ATP_VALID              0x08

        u_int                  sc_left_margin;
        u_int                  sc_right_margin;

        atp_stroke             sc_strokes[ATP_MAX_STROKES];
        u_int                  sc_n_strokes;

        int8_t                *sensor_data; /* from interrupt packet */
        int                   *base_x;      /* base sensor readings */
        int                   *base_y;
        int                   *cur_x;       /* current sensor readings */
        int                   *cur_y;
        int                   *pressure_x;  /* computed pressures */
        int                   *pressure_y;

        u_int                  sc_idlecount; /* preceding idle interrupts */
#define ATP_IDLENESS_THRESHOLD 10

        struct timeval         sc_reap_time;
        struct timeval         sc_reap_ctime; /*ctime of siblings to be reaped*/
};

/*
 * The last byte of the sensor data contains status bits; the
 * following values define the meanings of these bits.
 */
enum atp_status_bits {
        ATP_STATUS_BUTTON      = (uint8_t)0x01, /* The button was pressed */
        ATP_STATUS_BASE_UPDATE = (uint8_t)0x04, /* Data from an untouched pad.*/
};

typedef enum interface_mode {
        RAW_SENSOR_MODE = (uint8_t)0x04,
        HID_MODE        = (uint8_t)0x08
} interface_mode;

/*
 * function prototypes
 */
static usb_fifo_cmd_t   atp_start_read;
static usb_fifo_cmd_t   atp_stop_read;
static usb_fifo_open_t  atp_open;
static usb_fifo_close_t atp_close;
static usb_fifo_ioctl_t atp_ioctl;

static struct usb_fifo_methods atp_fifo_methods = {
        .f_open       = &atp_open,
        .f_close      = &atp_close,
        .f_ioctl      = &atp_ioctl,
        .f_start_read = &atp_start_read,
        .f_stop_read  = &atp_stop_read,
        .basename[0]  = ATP_DRIVER_NAME,
};

/* device initialization and shutdown */
static usb_error_t   atp_req_get_report(struct usb_device *udev, void *data);
static int           atp_set_device_mode(device_t dev, interface_mode mode);
static void          atp_reset_callback(struct usb_xfer *, usb_error_t);
static int           atp_enable(struct atp_softc *sc);
static void          atp_disable(struct atp_softc *sc);
static int           atp_softc_populate(struct atp_softc *);
static void          atp_softc_unpopulate(struct atp_softc *);

/* sensor interpretation */
static __inline void atp_interpret_sensor_data(const int8_t *, u_int, atp_axis,
                         int *, atp_protocol);
static __inline void atp_get_pressures(int *, const int *, const int *, int);
static void          atp_detect_pspans(int *, u_int, u_int, atp_pspan *,
                         u_int *);

/* movement detection */
static boolean_t     atp_match_stroke_component(atp_stroke_component *,
                         const atp_pspan *, atp_stroke_type);
static void          atp_match_strokes_against_pspans(struct atp_softc *,
                         atp_axis, atp_pspan *, u_int, u_int);
static boolean_t     atp_update_strokes(struct atp_softc *,
                         atp_pspan *, u_int, atp_pspan *, u_int);
static __inline void atp_add_stroke(struct atp_softc *, const atp_pspan *,
                         const atp_pspan *);
static void          atp_add_new_strokes(struct atp_softc *, atp_pspan *,
                         u_int, atp_pspan *, u_int);
static void          atp_advance_stroke_state(struct atp_softc *,
                         atp_stroke *, boolean_t *);
static void          atp_terminate_stroke(struct atp_softc *, u_int);
static __inline boolean_t atp_stroke_has_small_movement(const atp_stroke *);
static __inline void atp_update_pending_mickeys(atp_stroke_component *);
static void          atp_compute_smoothening_scale_ratio(atp_stroke *, int *,
                         int *);
static boolean_t     atp_compute_stroke_movement(atp_stroke *);

/* tap detection */
static __inline void atp_setup_reap_time(struct atp_softc *, struct timeval *);
static void          atp_reap_zombies(struct atp_softc *, u_int *, u_int *);
static void          atp_convert_to_slide(struct atp_softc *, atp_stroke *);

/* updating fifo */
static void          atp_reset_buf(struct atp_softc *sc);
static void          atp_add_to_queue(struct atp_softc *, int, int, uint32_t);


usb_error_t
atp_req_get_report(struct usb_device *udev, void *data)
{
        struct usb_device_request req;

        req.bmRequestType = UT_READ_CLASS_INTERFACE;
        req.bRequest = UR_GET_REPORT;
        USETW2(req.wValue, (uint8_t)0x03 /* type */, (uint8_t)0x00 /* id */);
        USETW(req.wIndex, 0);
        USETW(req.wLength, MODE_LENGTH);

        return (usbd_do_request(udev, NULL /* mutex */, &req, data));
}

static int
atp_set_device_mode(device_t dev, interface_mode mode)
{
        struct atp_softc     *sc;
        usb_device_request_t  req;
        usb_error_t           err;

        if ((mode != RAW_SENSOR_MODE) && (mode != HID_MODE))
                return (ENXIO);

        sc = device_get_softc(dev);

        sc->sc_mode_bytes[0] = mode;
        req.bmRequestType = UT_WRITE_CLASS_INTERFACE;
        req.bRequest = UR_SET_REPORT;
        USETW2(req.wValue, (uint8_t)0x03 /* type */, (uint8_t)0x00 /* id */);
        USETW(req.wIndex, 0);
        USETW(req.wLength, MODE_LENGTH);
        err = usbd_do_request(sc->sc_usb_device, NULL, &req, sc->sc_mode_bytes);
        if (err != USB_ERR_NORMAL_COMPLETION)
                return (ENXIO);

        return (0);
}

void
atp_reset_callback(struct usb_xfer *xfer, usb_error_t error)
{
        usb_device_request_t   req;
        struct usb_page_cache *pc;
        struct atp_softc      *sc = usbd_xfer_softc(xfer);

        switch (USB_GET_STATE(xfer)) {
        case USB_ST_SETUP:
                sc->sc_mode_bytes[0] = RAW_SENSOR_MODE;
                req.bmRequestType = UT_WRITE_CLASS_INTERFACE;
                req.bRequest = UR_SET_REPORT;
                USETW2(req.wValue,
                    (uint8_t)0x03 /* type */, (uint8_t)0x00 /* id */);
                USETW(req.wIndex, 0);
                USETW(req.wLength, MODE_LENGTH);

                pc = usbd_xfer_get_frame(xfer, 0);
                usbd_copy_in(pc, 0, &req, sizeof(req));
                pc = usbd_xfer_get_frame(xfer, 1);
                usbd_copy_in(pc, 0, sc->sc_mode_bytes, MODE_LENGTH);

                usbd_xfer_set_frame_len(xfer, 0, sizeof(req));
                usbd_xfer_set_frame_len(xfer, 1, MODE_LENGTH);
                usbd_xfer_set_frames(xfer, 2);
                usbd_transfer_submit(xfer);
                break;

        case USB_ST_TRANSFERRED:
        default:
                break;
        }
}

static int
atp_enable(struct atp_softc *sc)
{
        /* Allocate the dynamic buffers */
        if (atp_softc_populate(sc) != 0) {
                atp_softc_unpopulate(sc);
                return (ENOMEM);
        }

        /* reset status */
        memset(sc->sc_strokes, 0, sizeof(sc->sc_strokes));
        sc->sc_n_strokes = 0;
        memset(&sc->sc_status, 0, sizeof(sc->sc_status));
        sc->sc_idlecount = 0;
        sc->sc_state |= ATP_ENABLED;

        DPRINTFN(ATP_LLEVEL_INFO, "enabled atp\n");
        return (0);
}

static void
atp_disable(struct atp_softc *sc)
{
        atp_softc_unpopulate(sc);

        sc->sc_state &= ~(ATP_ENABLED | ATP_VALID);
        DPRINTFN(ATP_LLEVEL_INFO, "disabled atp\n");
}

/* Allocate dynamic memory for some fields in softc. */
static int
atp_softc_populate(struct atp_softc *sc)
{
        const struct atp_dev_params *params = sc->sc_params;

        if (params == NULL) {
                DPRINTF("params uninitialized!\n");
                return (ENXIO);
        }
        if (params->data_len) {
                sc->sensor_data = malloc(params->data_len * sizeof(int8_t),
                    M_USB, M_WAITOK);
                if (sc->sensor_data == NULL) {
                        DPRINTF("mem for sensor_data\n");
                        return (ENXIO);
                }
        }

        if (params->n_xsensors != 0) {
                sc->base_x = malloc(params->n_xsensors * sizeof(*(sc->base_x)),
                    M_USB, M_WAITOK);
                if (sc->base_x == NULL) {
                        DPRINTF("mem for sc->base_x\n");
                        return (ENXIO);
                }

                sc->cur_x = malloc(params->n_xsensors * sizeof(*(sc->cur_x)),
                    M_USB, M_WAITOK);
                if (sc->cur_x == NULL) {
                        DPRINTF("mem for sc->cur_x\n");
                        return (ENXIO);
                }

                sc->pressure_x =
                        malloc(params->n_xsensors * sizeof(*(sc->pressure_x)),
                            M_USB, M_WAITOK);
                if (sc->pressure_x == NULL) {
                        DPRINTF("mem. for pressure_x\n");
                        return (ENXIO);
                }
        }

        if (params->n_ysensors != 0) {
                sc->base_y = malloc(params->n_ysensors * sizeof(*(sc->base_y)),
                    M_USB, M_WAITOK);
                if (sc->base_y == NULL) {
                        DPRINTF("mem for base_y\n");
                        return (ENXIO);
                }

                sc->cur_y = malloc(params->n_ysensors * sizeof(*(sc->cur_y)),
                    M_USB, M_WAITOK);
                if (sc->cur_y == NULL) {
                        DPRINTF("mem for cur_y\n");
                        return (ENXIO);
                }

                sc->pressure_y =
                        malloc(params->n_ysensors * sizeof(*(sc->pressure_y)),
                            M_USB, M_WAITOK);
                if (sc->pressure_y == NULL) {
                        DPRINTF("mem. for pressure_y\n");
                        return (ENXIO);
                }
        }

        return (0);
}

/* Free dynamic memory allocated for some fields in softc. */
static void
atp_softc_unpopulate(struct atp_softc *sc)
{
        const struct atp_dev_params *params = sc->sc_params;

        if (params == NULL) {
                return;
        }
        if (params->n_xsensors != 0) {
                if (sc->base_x != NULL) {
                        free(sc->base_x, M_USB);
                        sc->base_x = NULL;
                }

                if (sc->cur_x != NULL) {
                        free(sc->cur_x, M_USB);
                        sc->cur_x = NULL;
                }

                if (sc->pressure_x != NULL) {
                        free(sc->pressure_x, M_USB);
                        sc->pressure_x = NULL;
                }
        }
        if (params->n_ysensors != 0) {
                if (sc->base_y != NULL) {
                        free(sc->base_y, M_USB);
                        sc->base_y = NULL;
                }

                if (sc->cur_y != NULL) {
                        free(sc->cur_y, M_USB);
                        sc->cur_y = NULL;
                }

                if (sc->pressure_y != NULL) {
                        free(sc->pressure_y, M_USB);
                        sc->pressure_y = NULL;
                }
        }
        if (sc->sensor_data != NULL) {
                free(sc->sensor_data, M_USB);
                sc->sensor_data = NULL;
        }
}

/*
 * Interpret the data from the X and Y pressure sensors. This function
 * is called separately for the X and Y sensor arrays. The data in the
 * USB packet is laid out in the following manner:
 *
 * sensor_data:
 *            --,--,Y1,Y2,--,Y3,Y4,--,Y5,...,Y10, ... X1,X2,--,X3,X4
 *  indices:   0  1  2  3  4  5  6  7  8 ...  15  ... 20 21 22 23 24
 *
 * '--' (in the above) indicates that the value is unimportant.
 *
 * Information about the above layout was obtained from the
 * implementation of the AppleTouch driver in Linux.
 *
 * parameters:
 *   sensor_data
 *       raw sensor data from the USB packet.
 *   num
 *       The number of elements in the array 'arr'.
 *   axis
 *       Axis of data to fetch
 *   arr
 *       The array to be initialized with the readings.
 *   prot
 *       The protocol to use to interpret the data
 */
static __inline void
atp_interpret_sensor_data(const int8_t *sensor_data, u_int num, atp_axis axis,
    int *arr, atp_protocol prot)
{
        u_int i;
        u_int di;   /* index into sensor data */

        switch (prot) {
        case ATP_PROT_GEYSER1:
                /*
                 * For Geyser 1, the sensors are laid out in pairs
                 * every 5 bytes.
                 */
                for (i = 0, di = (axis == Y) ? 1 : 2; i < 8; di += 5, i++) {
                        arr[i] = sensor_data[di];
                        arr[i+8] = sensor_data[di+2];
                        if (axis == X && num > 16)
                                arr[i+16] = sensor_data[di+40];
                }

                break;
        case ATP_PROT_GEYSER2:
        case ATP_PROT_GEYSER3:
                for (i = 0, di = (axis == Y) ? 2 : 20; i < num; /* empty */ ) {
                        arr[i++] = sensor_data[di++];
                        arr[i++] = sensor_data[di++];
                        di++;
                }
                break;
        }
}

static __inline void
atp_get_pressures(int *p, const int *cur, const int *base, int n)
{
        int i;

        for (i = 0; i < n; i++) {
                p[i] = cur[i] - base[i];
                if (p[i] > 127)
                        p[i] -= 256;
                if (p[i] < -127)
                        p[i] += 256;
                if (p[i] < 0)
                        p[i] = 0;

                /*
                 * Shave off pressures below the noise-pressure
                 * threshold; this will reduce the contribution from
                 * lower pressure readings.
                 */
                if ((u_int)p[i] <= atp_sensor_noise_threshold)
                        p[i] = 0; /* filter away noise */
                else
                        p[i] -= atp_sensor_noise_threshold;
        }
}

static void
atp_detect_pspans(int *p, u_int num_sensors,
    u_int       max_spans, /* max # of pspans permitted */
    atp_pspan  *spans,     /* finger spans */
    u_int      *nspans_p)  /* num spans detected */
{
        u_int i;
        int   maxp;             /* max pressure seen within a span */
        u_int num_spans = 0;

        enum atp_pspan_state {
                ATP_PSPAN_INACTIVE,
                ATP_PSPAN_INCREASING,
                ATP_PSPAN_DECREASING,
        } state; /* state of the pressure span */

        /*
         * The following is a simple state machine to track
         * the phase of the pressure span.
         */
        memset(spans, 0, max_spans * sizeof(atp_pspan));
        maxp = 0;
        state = ATP_PSPAN_INACTIVE;
        for (i = 0; i < num_sensors; i++) {
                if (num_spans >= max_spans)
                        break;

                if (p[i] == 0) {
                        if (state == ATP_PSPAN_INACTIVE) {
                                /*
                                 * There is no pressure information for this
                                 * sensor, and we aren't tracking a finger.
                                 */
                                continue;
                        } else {
                                state = ATP_PSPAN_INACTIVE;
                                maxp = 0;
                                num_spans++;
                        }
                } else {
                        switch (state) {
                        case ATP_PSPAN_INACTIVE:
                                state = ATP_PSPAN_INCREASING;
                                maxp  = p[i];
                                break;

                        case ATP_PSPAN_INCREASING:
                                if (p[i] > maxp)
                                        maxp = p[i];
                                else if (p[i] <= (maxp >> 1))
                                        state = ATP_PSPAN_DECREASING;
                                break;

                        case ATP_PSPAN_DECREASING:
                                if (p[i] > p[i - 1]) {
                                        /*
                                         * This is the beginning of
                                         * another span; change state
                                         * to give the appearance that
                                         * we're starting from an
                                         * inactive span, and then
                                         * re-process this reading in
                                         * the next iteration.
                                         */
                                        num_spans++;
                                        state = ATP_PSPAN_INACTIVE;
                                        maxp  = 0;
                                        i--;
                                        continue;
                                }
                                break;
                        }

                        /* Update the finger span with this reading. */
                        spans[num_spans].width++;
                        spans[num_spans].cum += p[i];
                        spans[num_spans].cog += p[i] * (i + 1);
                }
        }
        if (state != ATP_PSPAN_INACTIVE)
                num_spans++;    /* close the last finger span */

        /* post-process the spans */
        for (i = 0; i < num_spans; i++) {
                /* filter away unwanted pressure spans */
                if ((spans[i].cum < atp_pspan_min_cum_pressure) ||
                    (spans[i].width > atp_pspan_max_width)) {
                        if ((i + 1) < num_spans) {
                                memcpy(&spans[i], &spans[i + 1],
                                    (num_spans - i - 1) * sizeof(atp_pspan));
                                i--;
                        }
                        num_spans--;
                        continue;
                }

                /* compute this span's representative location */
                spans[i].loc = spans[i].cog * atp_mickeys_scale_factor /
                        spans[i].cum;

                spans[i].matched = FALSE; /* not yet matched against a stroke */
        }

        *nspans_p = num_spans;
}

/*
 * Match a pressure-span against a stroke-component. If there is a
 * match, update the component's state and return TRUE.
 */
static boolean_t
atp_match_stroke_component(atp_stroke_component *component,
    const atp_pspan *pspan, atp_stroke_type stroke_type)
{
        int   delta_mickeys;
        u_int min_pressure;

        delta_mickeys = pspan->loc - component->loc;

        if ((u_int)abs(delta_mickeys) > atp_max_delta_mickeys)
                return (FALSE); /* the finger span is too far out; no match */

        component->loc          = pspan->loc;

        /*
         * A sudden and significant increase in a pspan's cumulative
         * pressure indicates the incidence of a new finger
         * contact. This usually revises the pspan's
         * centre-of-gravity, and hence the location of any/all
         * matching stroke component(s). But such a change should
         * *not* be interpreted as a movement.
         */
        if (pspan->cum > ((3 * component->cum_pressure) >> 1))
                delta_mickeys = 0;

        component->cum_pressure = pspan->cum;
        if (pspan->cum > component->max_cum_pressure)
                component->max_cum_pressure = pspan->cum;

        /*
         * Disregard the component's movement if its cumulative
         * pressure drops below a fraction of the maximum; this
         * fraction is determined based on the stroke's type.
         */
        if (stroke_type == ATP_STROKE_TOUCH)
                min_pressure = (3 * component->max_cum_pressure) >> 2;
        else
                min_pressure = component->max_cum_pressure >> 2;
        if (component->cum_pressure < min_pressure)
                delta_mickeys = 0;

        component->delta_mickeys = delta_mickeys;
        return (TRUE);
}

static void
atp_match_strokes_against_pspans(struct atp_softc *sc, atp_axis axis,
    atp_pspan *pspans, u_int n_pspans, u_int repeat_count)
{
        u_int i, j;
        u_int repeat_index = 0;

        /* Determine the index of the multi-span. */
        if (repeat_count) {
                u_int cum = 0;
                for (i = 0; i < n_pspans; i++) {
                        if (pspans[i].cum > cum) {
                                repeat_index = i;
                                cum = pspans[i].cum;
                        }
                }
        }

        for (i = 0; i < sc->sc_n_strokes; i++) {
                atp_stroke *stroke  = &sc->sc_strokes[i];
                if (stroke->components[axis].matched)
                        continue; /* skip matched components */

                for (j = 0; j < n_pspans; j++) {
                        if (pspans[j].matched)
                                continue; /* skip matched pspans */

                        if (atp_match_stroke_component(
                                    &stroke->components[axis], &pspans[j],
                                    stroke->type)) {
                                /* There is a match. */
                                stroke->components[axis].matched = TRUE;

                                /* Take care to repeat at the multi-span. */
                                if ((repeat_count > 0) && (j == repeat_index))
                                        repeat_count--;
                                else
                                        pspans[j].matched = TRUE;

                                break; /* skip to the next stroke */
                        }
                } /* loop over pspans */
        } /* loop over strokes */
}

/*
 * Update strokes by matching against current pressure-spans.
 * Return TRUE if any movement is detected.
 */
static boolean_t
atp_update_strokes(struct atp_softc *sc, atp_pspan *pspans_x,
    u_int n_xpspans, atp_pspan *pspans_y, u_int n_ypspans)
{
        u_int       i, j;
        atp_stroke *stroke;
        boolean_t   movement = FALSE;
        u_int       repeat_count = 0;

        /* Reset X and Y components of all strokes as unmatched. */
        for (i = 0; i < sc->sc_n_strokes; i++) {
                stroke = &sc->sc_strokes[i];
                stroke->components[X].matched = FALSE;
                stroke->components[Y].matched = FALSE;
        }

        /*
         * Usually, the X and Y pspans come in pairs (the common case
         * being a single pair). It is possible, however, that
         * multiple contacts resolve to a single pspan along an
         * axis, as illustrated in the following:
         *
         *   F = finger-contact
         *
         *                pspan  pspan
         *        +-----------------------+
         *        |         .      .      |
         *        |         .      .      |
         *        |         .      .      |
         *        |         .      .      |
         *  pspan |.........F......F      |
         *        |                       |
         *        |                       |
         *        |                       |
         *        +-----------------------+
         *
         *
         * The above case can be detected by a difference in the
         * number of X and Y pspans. When this happens, X and Y pspans
         * aren't easy to pair or match against strokes.
         *
         * When X and Y pspans differ in number, the axis with the
         * smaller number of pspans is regarded as having a repeating
         * pspan (or a multi-pspan)--in the above illustration, the
         * Y-axis has a repeating pspan. Our approach is to try to
         * match the multi-pspan repeatedly against strokes. The
         * difference between the number of X and Y pspans gives us a
         * crude repeat_count for matching multi-pspans--i.e. the
         * multi-pspan along the Y axis (above) has a repeat_count of 1.
         */
        repeat_count = abs(n_xpspans - n_ypspans);

        atp_match_strokes_against_pspans(sc, X, pspans_x, n_xpspans,
            (((repeat_count != 0) && ((n_xpspans < n_ypspans))) ?
                repeat_count : 0));
        atp_match_strokes_against_pspans(sc, Y, pspans_y, n_ypspans,
            (((repeat_count != 0) && (n_ypspans < n_xpspans)) ?
                repeat_count : 0));

        /* Update the state of strokes based on the above pspan matches. */
        for (i = 0; i < sc->sc_n_strokes; i++) {
                stroke = &sc->sc_strokes[i];
                if (stroke->components[X].matched &&
                    stroke->components[Y].matched) {
                        atp_advance_stroke_state(sc, stroke, &movement);
                } else {
                        /*
                         * At least one component of this stroke
                         * didn't match against current pspans;
                         * terminate it.
                         */
                        atp_terminate_stroke(sc, i);
                }
        }

        /* Add new strokes for pairs of unmatched pspans */
        for (i = 0; i < n_xpspans; i++) {
                if (pspans_x[i].matched == FALSE) break;
        }
        for (j = 0; j < n_ypspans; j++) {
                if (pspans_y[j].matched == FALSE) break;
        }
        if ((i < n_xpspans) && (j < n_ypspans)) {
#ifdef USB_DEBUG
                if (atp_debug >= ATP_LLEVEL_INFO) {
                        printf("unmatched pspans:");
                        for (; i < n_xpspans; i++) {
                                if (pspans_x[i].matched)
                                        continue;
                                printf(" X:[loc:%u,cum:%u]",
                                    pspans_x[i].loc, pspans_x[i].cum);
                        }
                        for (; j < n_ypspans; j++) {
                                if (pspans_y[j].matched)
                                        continue;
                                printf(" Y:[loc:%u,cum:%u]",
                                    pspans_y[j].loc, pspans_y[j].cum);
                        }
                        printf("\n");
                }
#endif /* USB_DEBUG */
                if ((n_xpspans == 1) && (n_ypspans == 1))
                        /* The common case of a single pair of new pspans. */
                        atp_add_stroke(sc, &pspans_x[0], &pspans_y[0]);
                else
                        atp_add_new_strokes(sc,
                            pspans_x, n_xpspans,
                            pspans_y, n_ypspans);
        }

#ifdef USB_DEBUG
        if (atp_debug >= ATP_LLEVEL_INFO) {
                for (i = 0; i < sc->sc_n_strokes; i++) {
                        atp_stroke *stroke = &sc->sc_strokes[i];

                        printf(" %s%clc:%u,dm:%d,pnd:%d,cum:%d,max:%d,mv:%d%c"
                            ",%clc:%u,dm:%d,pnd:%d,cum:%d,max:%d,mv:%d%c",
                            (stroke->flags & ATSF_ZOMBIE) ? "zomb:" : "",
                            (stroke->type == ATP_STROKE_TOUCH) ? '[' : '<',
                            stroke->components[X].loc,
                            stroke->components[X].delta_mickeys,
                            stroke->components[X].pending,
                            stroke->components[X].cum_pressure,
                            stroke->components[X].max_cum_pressure,
                            stroke->components[X].movement,
                            (stroke->type == ATP_STROKE_TOUCH) ? ']' : '>',
                            (stroke->type == ATP_STROKE_TOUCH) ? '[' : '<',
                            stroke->components[Y].loc,
                            stroke->components[Y].delta_mickeys,
                            stroke->components[Y].pending,
                            stroke->components[Y].cum_pressure,
                            stroke->components[Y].max_cum_pressure,
                            stroke->components[Y].movement,
                            (stroke->type == ATP_STROKE_TOUCH) ? ']' : '>');
                }
                if (sc->sc_n_strokes)
                        printf("\n");
        }
#endif /* USB_DEBUG */

        return (movement);
}

/* Initialize a stroke using a pressure-span. */
static __inline void
atp_add_stroke(struct atp_softc *sc, const atp_pspan *pspan_x,
    const atp_pspan *pspan_y)
{
        atp_stroke *stroke;

        if (sc->sc_n_strokes >= ATP_MAX_STROKES)
                return;
        stroke = &sc->sc_strokes[sc->sc_n_strokes];

        memset(stroke, 0, sizeof(atp_stroke));

        /*
         * Strokes begin as potential touches. If a stroke survives
         * longer than a threshold, or if it records significant
         * cumulative movement, then it is considered a 'slide'.
         */
        stroke->type = ATP_STROKE_TOUCH;
        microtime(&stroke->ctime);
        stroke->age  = 1;       /* Unit: interrupts */

        stroke->components[X].loc              = pspan_x->loc;
        stroke->components[X].cum_pressure     = pspan_x->cum;
        stroke->components[X].max_cum_pressure = pspan_x->cum;
        stroke->components[X].matched          = TRUE;

        stroke->components[Y].loc              = pspan_y->loc;
        stroke->components[Y].cum_pressure     = pspan_y->cum;
        stroke->components[Y].max_cum_pressure = pspan_y->cum;
        stroke->components[Y].matched          = TRUE;

        sc->sc_n_strokes++;
        if (sc->sc_n_strokes > 1) {
                /* Reset double-tap-n-drag if we have more than one strokes. */
                sc->sc_state &= ~ATP_DOUBLE_TAP_DRAG;
        }

        DPRINTFN(ATP_LLEVEL_INFO, "[%u,%u], time: %u,%ld\n",
            stroke->components[X].loc,
            stroke->components[Y].loc,
            (unsigned int)stroke->ctime.tv_sec,
            (unsigned long int)stroke->ctime.tv_usec);
}

static void
atp_add_new_strokes(struct atp_softc *sc, atp_pspan *pspans_x,
    u_int n_xpspans, atp_pspan *pspans_y, u_int n_ypspans)
{
        atp_pspan spans[2][ATP_MAX_PSPANS_PER_AXIS];
        u_int nspans[2];
        u_int i;
        u_int j;

        /* Copy unmatched pspans into the local arrays. */
        for (i = 0, nspans[X] = 0; i < n_xpspans; i++) {
                if (pspans_x[i].matched == FALSE) {
                        spans[X][nspans[X]] = pspans_x[i];
                        nspans[X]++;
                }
        }
        for (j = 0, nspans[Y] = 0; j < n_ypspans; j++) {
                if (pspans_y[j].matched == FALSE) {
                        spans[Y][nspans[Y]] = pspans_y[j];
                        nspans[Y]++;
                }
        }

        if (nspans[X] == nspans[Y]) {
                /* Create new strokes from pairs of unmatched pspans */
                for (i = 0, j = 0; (i < nspans[X]) && (j < nspans[Y]); i++, j++)
                        atp_add_stroke(sc, &spans[X][i], &spans[Y][j]);
        } else {
                u_int    cum = 0;
                atp_axis repeat_axis;      /* axis with multi-pspans */
                u_int    repeat_count;     /* repeat count for the multi-pspan*/
                u_int    repeat_index = 0; /* index of the multi-span */

                repeat_axis  = (nspans[X] > nspans[Y]) ? Y : X;
                repeat_count = abs(nspans[X] - nspans[Y]);
                for (i = 0; i < nspans[repeat_axis]; i++) {
                        if (spans[repeat_axis][i].cum > cum) {
                                repeat_index = i;
                                cum = spans[repeat_axis][i].cum;
                        }
                }

                /* Create new strokes from pairs of unmatched pspans */
                i = 0, j = 0;
                for (; (i < nspans[X]) && (j < nspans[Y]); i++, j++) {
                        atp_add_stroke(sc, &spans[X][i], &spans[Y][j]);

                        /* Take care to repeat at the multi-pspan. */
                        if (repeat_count > 0) {
                                if ((repeat_axis == X) &&
                                    (repeat_index == i)) {
                                        i--; /* counter loop increment */
                                        repeat_count--;
                                } else if ((repeat_axis == Y) &&
                                    (repeat_index == j)) {
                                        j--; /* counter loop increment */
                                        repeat_count--;
                                }
                        }
                }
        }
}

/*
 * Advance the state of this stroke--and update the out-parameter
 * 'movement' as a side-effect.
 */
void
atp_advance_stroke_state(struct atp_softc *sc, atp_stroke *stroke,
    boolean_t *movement)
{
        stroke->age++;
        if (stroke->age <= atp_stroke_maturity_threshold) {
                /* Avoid noise from immature strokes. */
                stroke->components[X].delta_mickeys = 0;
                stroke->components[Y].delta_mickeys = 0;
        }

        /* Revitalize stroke if it had previously been marked as a zombie. */
        if (stroke->flags & ATSF_ZOMBIE)
                stroke->flags &= ~ATSF_ZOMBIE;

        if (atp_compute_stroke_movement(stroke))
                *movement = TRUE;

        if (stroke->type != ATP_STROKE_TOUCH)
                return;

        /* Convert touch strokes to slides upon detecting movement or age. */
        if (stroke->cum_movement >= atp_slide_min_movement) {
                atp_convert_to_slide(sc, stroke);
        } else {
                /* If a touch stroke is found to be older than the
                 * touch-timeout threshold, it should be converted to
                 * a slide; except if there is a co-incident sibling
                 * with a later creation time.
                 *
                 * When multiple fingers make contact with the
                 * touchpad, they are likely to be separated in their
                 * times of incidence.  During a multi-finger tap,
                 * therefore, the last finger to make
                 * contact--i.e. the one with the latest
                 * 'ctime'--should be used to determine how the
                 * touch-siblings get treated; otherwise older
                 * siblings may lapse the touch-timeout and get
                 * converted into slides prematurely.  The following
                 * loop determines if there exists another touch
                 * stroke with a larger 'ctime' than the current
                 * stroke (NOTE: zombies with a larger 'ctime' are
                 * also considered) .
                 */

                u_int i;
                for (i = 0; i < sc->sc_n_strokes; i++) {
                        if ((&sc->sc_strokes[i] == stroke) ||
                            (sc->sc_strokes[i].type != ATP_STROKE_TOUCH))
                                continue;

                        if (timevalcmp(&sc->sc_strokes[i].ctime,
                                &stroke->ctime, >))
                                break;
                }
                if (i == sc->sc_n_strokes) {
                        /* Found no other touch stroke with a larger 'ctime'. */
                        struct timeval tdiff;

                        /* Compute the stroke's age. */
                        getmicrotime(&tdiff);
                        if (timevalcmp(&tdiff, &stroke->ctime, >))
                                timevalsub(&tdiff, &stroke->ctime);
                        else {
                                /*
                                 * If we are here, it is because getmicrotime
                                 * reported the current time as being behind
                                 * the stroke's start time; getmicrotime can
                                 * be imprecise.
                                 */
                                tdiff.tv_sec  = 0;
                                tdiff.tv_usec = 0;
                        }

                        if ((tdiff.tv_sec > (atp_touch_timeout / 1000000)) ||
                            ((tdiff.tv_sec == (atp_touch_timeout / 1000000)) &&
                                (tdiff.tv_usec >=
                                    (atp_touch_timeout % 1000000))))
                                atp_convert_to_slide(sc, stroke);
                }
        }
}

/* Switch a given touch stroke to being a slide. */
void
atp_convert_to_slide(struct atp_softc *sc, atp_stroke *stroke)
{
        stroke->type = ATP_STROKE_SLIDE;

        /* Are we at the beginning of a double-click-n-drag? */
        if ((sc->sc_n_strokes == 1) &&
            ((sc->sc_state & ATP_ZOMBIES_EXIST) == 0) &&
            timevalcmp(&stroke->ctime, &sc->sc_reap_time, >)) {
                struct timeval delta;
                struct timeval window = {
                        atp_double_tap_threshold / 1000000,
                        atp_double_tap_threshold % 1000000
                };

                delta = stroke->ctime;
                timevalsub(&delta, &sc->sc_reap_time);
                if (timevalcmp(&delta, &window, <=))
                        sc->sc_state |= ATP_DOUBLE_TAP_DRAG;
        }
}

/*
 * Terminate a stroke. While SLIDE strokes are dropped, TOUCH strokes
 * are retained as zombies so as to reap all their siblings together;
 * this helps establish the number of fingers involved in the tap.
 */
static void
atp_terminate_stroke(struct atp_softc *sc,
    u_int index) /* index of the stroke to be terminated */
{
        atp_stroke *s = &sc->sc_strokes[index];

        if (s->flags & ATSF_ZOMBIE) {
                return;
        }

        if ((s->type == ATP_STROKE_TOUCH) &&
            (s->age > atp_stroke_maturity_threshold)) {
                s->flags |= ATSF_ZOMBIE;

                /* If no zombies exist, then prepare to reap zombies later. */
                if ((sc->sc_state & ATP_ZOMBIES_EXIST) == 0) {
                        atp_setup_reap_time(sc, &s->ctime);
                        sc->sc_state |= ATP_ZOMBIES_EXIST;
                }
        } else {
                /* Drop this stroke. */
                memcpy(&sc->sc_strokes[index], &sc->sc_strokes[index + 1],
                    (sc->sc_n_strokes - index - 1) * sizeof(atp_stroke));
                sc->sc_n_strokes--;

                /*
                 * Reset the double-click-n-drag at the termination of
                 * any slide stroke.
                 */
                sc->sc_state &= ~ATP_DOUBLE_TAP_DRAG;
        }
}

static __inline boolean_t
atp_stroke_has_small_movement(const atp_stroke *stroke)
{
        return (((u_int)abs(stroke->components[X].delta_mickeys) <=
                atp_small_movement_threshold) &&
            ((u_int)abs(stroke->components[Y].delta_mickeys) <=
                atp_small_movement_threshold));
}

/*
 * Accumulate delta_mickeys into the component's 'pending' bucket; if
 * the aggregate exceeds the small_movement_threshold, then retain
 * delta_mickeys for later.
 */
static __inline void
atp_update_pending_mickeys(atp_stroke_component *component)
{
        component->pending += component->delta_mickeys;
        if ((u_int)abs(component->pending) <= atp_small_movement_threshold)
                component->delta_mickeys = 0;
        else {
                /*
                 * Penalise pending mickeys for having accumulated
                 * over short deltas. This operation has the effect of
                 * scaling down the cumulative contribution of short
                 * movements.
                 */
                component->pending -= (component->delta_mickeys << 1);
        }
}


static void
atp_compute_smoothening_scale_ratio(atp_stroke *stroke, int *numerator,
    int *denominator)
{
        int   dxdt;
        int   dydt;
        u_int vel_squared; /* Square of the velocity vector's magnitude. */
        u_int vel_squared_smooth;

        /* Table holding (10 * sqrt(x)) for x between 1 and 256. */
        static uint8_t sqrt_table[256] = {
                10, 14, 17, 20, 22, 24, 26, 28,
                30, 31, 33, 34, 36, 37, 38, 40,
                41, 42, 43, 44, 45, 46, 47, 48,
                50, 50, 51, 52, 53, 54, 55, 56,
                57, 58, 59, 60, 60, 61, 62, 63,
                64, 64, 65, 66, 67, 67, 68, 69,
                70, 70, 71, 72, 72, 73, 74, 74,
                75, 76, 76, 77, 78, 78, 79, 80,
                80, 81, 81, 82, 83, 83, 84, 84,
                85, 86, 86, 87, 87, 88, 88, 89,
                90, 90, 91, 91, 92, 92, 93, 93,
                94, 94, 95, 95, 96, 96, 97, 97,
                98, 98, 99, 100, 100, 100, 101, 101,
                102, 102, 103, 103, 104, 104, 105, 105,
                106, 106, 107, 107, 108, 108, 109, 109,
                110, 110, 110, 111, 111, 112, 112, 113,
                113, 114, 114, 114, 115, 115, 116, 116,
                117, 117, 117, 118, 118, 119, 119, 120,
                120, 120, 121, 121, 122, 122, 122, 123,
                123, 124, 124, 124, 125, 125, 126, 126,
                126, 127, 127, 128, 128, 128, 129, 129,
                130, 130, 130, 131, 131, 131, 132, 132,
                133, 133, 133, 134, 134, 134, 135, 135,
                136, 136, 136, 137, 137, 137, 138, 138,
                138, 139, 139, 140, 140, 140, 141, 141,
                141, 142, 142, 142, 143, 143, 143, 144,
                144, 144, 145, 145, 145, 146, 146, 146,
                147, 147, 147, 148, 148, 148, 149, 149,
                150, 150, 150, 150, 151, 151, 151, 152,
                152, 152, 153, 153, 153, 154, 154, 154,
                155, 155, 155, 156, 156, 156, 157, 157,
                157, 158, 158, 158, 159, 159, 159, 160
        };
        const u_int N = sizeof(sqrt_table) / sizeof(sqrt_table[0]);

        dxdt = stroke->components[X].delta_mickeys;
        dydt = stroke->components[Y].delta_mickeys;

        *numerator = 0, *denominator = 0; /* default values. */

        /* Compute a smoothened magnitude_squared of the stroke's velocity. */
        vel_squared = dxdt * dxdt + dydt * dydt;
        vel_squared_smooth = (3 * stroke->velocity_squared + vel_squared) >> 2;
        stroke->velocity_squared = vel_squared_smooth; /* retained as history */
        if ((vel_squared == 0) || (vel_squared_smooth == 0))
                return; /* returning (numerator == 0) will imply zero movement*/

        /*
         * In order to determine the overall movement scale factor,
         * we're actually interested in the effect of smoothening upon
         * the *magnitude* of velocity; i.e. we need to compute the
         * square-root of (vel_squared_smooth / vel_squared) in the
         * form of a numerator and denominator.
         */

        /* Keep within the bounds of the square-root table. */
        while ((vel_squared > N) || (vel_squared_smooth > N)) {
                /* Dividing uniformly by 2 won't disturb the final ratio. */
                vel_squared        >>= 1;
                vel_squared_smooth >>= 1;
        }

        *numerator   = sqrt_table[vel_squared_smooth - 1];
        *denominator = sqrt_table[vel_squared - 1];
}

/*
 * Compute a smoothened value for the stroke's movement from
 * delta_mickeys in the X and Y components.
 */
static boolean_t
atp_compute_stroke_movement(atp_stroke *stroke)
{
        int   num;              /* numerator of scale ratio */
        int   denom;            /* denominator of scale ratio */

        /*
         * Short movements are added first to the 'pending' bucket,
         * and then acted upon only when their aggregate exceeds a
         * threshold. This has the effect of filtering away movement
         * noise.
         */
        if (atp_stroke_has_small_movement(stroke)) {
                atp_update_pending_mickeys(&stroke->components[X]);
                atp_update_pending_mickeys(&stroke->components[Y]);
        } else {                /* large movement */
                /* clear away any pending mickeys if there are large movements*/
                stroke->components[X].pending = 0;
                stroke->components[Y].pending = 0;
        }

        /* Get the scale ratio and smoothen movement. */
        atp_compute_smoothening_scale_ratio(stroke, &num, &denom);
        if ((num == 0) || (denom == 0)) {
                stroke->components[X].movement = 0;
                stroke->components[Y].movement = 0;
                stroke->velocity_squared >>= 1; /* Erode velocity_squared. */
        } else {
                stroke->components[X].movement =
                        (stroke->components[X].delta_mickeys * num) / denom;
                stroke->components[Y].movement =
                        (stroke->components[Y].delta_mickeys * num) / denom;

                stroke->cum_movement +=
                        abs(stroke->components[X].movement) +
                        abs(stroke->components[Y].movement);
        }

        return ((stroke->components[X].movement != 0) ||
            (stroke->components[Y].movement != 0));
}

static __inline void
atp_setup_reap_time(struct atp_softc *sc, struct timeval *tvp)
{
        struct timeval reap_window = {
                ATP_ZOMBIE_STROKE_REAP_WINDOW / 1000000,
                ATP_ZOMBIE_STROKE_REAP_WINDOW % 1000000
        };

        microtime(&sc->sc_reap_time);
        timevaladd(&sc->sc_reap_time, &reap_window);

        sc->sc_reap_ctime = *tvp; /* ctime to reap */
}

static void
atp_reap_zombies(struct atp_softc *sc, u_int *n_reaped, u_int *reaped_xlocs)
{
        u_int       i;
        atp_stroke *stroke;

        *n_reaped = 0;
        for (i = 0; i < sc->sc_n_strokes; i++) {
                struct timeval  tdiff;

                stroke = &sc->sc_strokes[i];

                if ((stroke->flags & ATSF_ZOMBIE) == 0)
                        continue;

                /* Compare this stroke's ctime with the ctime being reaped. */
                if (timevalcmp(&stroke->ctime, &sc->sc_reap_ctime, >=)) {
                        tdiff = stroke->ctime;
                        timevalsub(&tdiff, &sc->sc_reap_ctime);
                } else {
                        tdiff = sc->sc_reap_ctime;
                        timevalsub(&tdiff, &stroke->ctime);
                }

                if ((tdiff.tv_sec > (ATP_COINCIDENCE_THRESHOLD / 1000000)) ||
                    ((tdiff.tv_sec == (ATP_COINCIDENCE_THRESHOLD / 1000000)) &&
                     (tdiff.tv_usec > (ATP_COINCIDENCE_THRESHOLD % 1000000)))) {
                        continue; /* Skip non-siblings. */
                }

                /*
                 * Reap this sibling zombie stroke.
                 */

                if (reaped_xlocs != NULL)
                        reaped_xlocs[*n_reaped] = stroke->components[X].loc;

                /* Erase the stroke from the sc. */
                memcpy(&stroke[i], &stroke[i + 1],
                    (sc->sc_n_strokes - i - 1) * sizeof(atp_stroke));
                sc->sc_n_strokes--;

                *n_reaped += 1;
                --i; /* Decr. i to keep it unchanged for the next iteration */
        }

        DPRINTFN(ATP_LLEVEL_INFO, "reaped %u zombies\n", *n_reaped);

        /* There could still be zombies remaining in the system. */
        for (i = 0; i < sc->sc_n_strokes; i++) {
                stroke = &sc->sc_strokes[i];
                if (stroke->flags & ATSF_ZOMBIE) {
                        DPRINTFN(ATP_LLEVEL_INFO, "zombies remain!\n");
                        atp_setup_reap_time(sc, &stroke->ctime);
                        return;
                }
        }

        /* If we reach here, then no more zombies remain. */
        sc->sc_state &= ~ATP_ZOMBIES_EXIST;
}


/* Device methods. */
static device_probe_t  atp_probe;
static device_attach_t atp_attach;
static device_detach_t atp_detach;
static usb_callback_t  atp_intr;

static const struct usb_config atp_config[ATP_N_TRANSFER] = {
        [ATP_INTR_DT] = {
                .type      = UE_INTERRUPT,
                .endpoint  = UE_ADDR_ANY,
                .direction = UE_DIR_IN,
                .flags = {
                        .pipe_bof = 1,
                        .short_xfer_ok = 1,
                },
                .bufsize   = 0, /* use wMaxPacketSize */
                .callback  = &atp_intr,
        },
        [ATP_RESET] = {
                .type      = UE_CONTROL,
                .endpoint  = 0, /* Control pipe */
                .direction = UE_DIR_ANY,
                .bufsize = sizeof(struct usb_device_request) + MODE_LENGTH,
                .callback  = &atp_reset_callback,
                .interval = 0,  /* no pre-delay */
        },
};

static int
atp_probe(device_t self)
{
        struct usb_attach_arg *uaa = device_get_ivars(self);

        if (uaa->usb_mode != USB_MODE_HOST)
                return (ENXIO);

        if ((uaa->info.bInterfaceClass != UICLASS_HID) ||
            (uaa->info.bInterfaceProtocol != UIPROTO_MOUSE))
                return (ENXIO);

        return (usbd_lookup_id_by_uaa(atp_devs, sizeof(atp_devs), uaa));
}

static int
atp_attach(device_t dev)
{
        struct atp_softc      *sc = device_get_softc(dev);
        struct usb_attach_arg *uaa = device_get_ivars(dev);
        usb_error_t            err;

        DPRINTFN(ATP_LLEVEL_INFO, "sc=%p\n", sc);

        sc->sc_dev        = dev;
        sc->sc_usb_device = uaa->device;

        /*
         * By default the touchpad behaves like an HID device, sending
         * packets with reportID = 2. Such reports contain only
         * limited information--they encode movement deltas and button
         * events,--but do not include data from the pressure
         * sensors. The device input mode can be switched from HID
         * reports to raw sensor data using vendor-specific USB
         * control commands; but first the mode must be read.
         */
        err = atp_req_get_report(sc->sc_usb_device, sc->sc_mode_bytes);
        if (err != USB_ERR_NORMAL_COMPLETION) {
                DPRINTF("failed to read device mode (%d)\n", err);
                return (ENXIO);
        }

        if (atp_set_device_mode(dev, RAW_SENSOR_MODE) != 0) {
                DPRINTF("failed to set mode to 'RAW_SENSOR' (%d)\n", err);
                return (ENXIO);
        }

        mtx_init(&sc->sc_mutex, "atpmtx", NULL, MTX_DEF | MTX_RECURSE);

        err = usbd_transfer_setup(uaa->device,
            &uaa->info.bIfaceIndex, sc->sc_xfer, atp_config,
            ATP_N_TRANSFER, sc, &sc->sc_mutex);

        if (err) {
                DPRINTF("error=%s\n", usbd_errstr(err));
                goto detach;
        }

        if (usb_fifo_attach(sc->sc_usb_device, sc, &sc->sc_mutex,
                &atp_fifo_methods, &sc->sc_fifo,
                device_get_unit(dev), -1, uaa->info.bIfaceIndex,
                UID_ROOT, GID_OPERATOR, 0644)) {
                goto detach;
        }

        device_set_usb_desc(dev);

        sc->sc_params           = &atp_dev_params[uaa->driver_info];

        sc->sc_hw.buttons       = 3;
        sc->sc_hw.iftype        = MOUSE_IF_USB;
        sc->sc_hw.type          = MOUSE_PAD;
        sc->sc_hw.model         = MOUSE_MODEL_GENERIC;
        sc->sc_hw.hwid          = 0;
        sc->sc_mode.protocol    = MOUSE_PROTO_MSC;
        sc->sc_mode.rate        = -1;
        sc->sc_mode.resolution  = MOUSE_RES_UNKNOWN;
        sc->sc_mode.accelfactor = 0;
        sc->sc_mode.level       = 0;
        sc->sc_mode.packetsize  = MOUSE_MSC_PACKETSIZE;
        sc->sc_mode.syncmask[0] = MOUSE_MSC_SYNCMASK;
        sc->sc_mode.syncmask[1] = MOUSE_MSC_SYNC;

        sc->sc_state            = 0;

        sc->sc_left_margin  = atp_mickeys_scale_factor;
        sc->sc_right_margin = (sc->sc_params->n_xsensors - 1) *
                atp_mickeys_scale_factor;

        return (0);

detach:
        atp_detach(dev);
        return (ENOMEM);
}

static int
atp_detach(device_t dev)
{
        struct atp_softc *sc;

        sc = device_get_softc(dev);
        if (sc->sc_state & ATP_ENABLED) {
                mtx_lock(&sc->sc_mutex);
                atp_disable(sc);
                mtx_unlock(&sc->sc_mutex);
        }

        usb_fifo_detach(&sc->sc_fifo);

        usbd_transfer_unsetup(sc->sc_xfer, ATP_N_TRANSFER);

        mtx_destroy(&sc->sc_mutex);

        return (0);
}

static void
atp_intr(struct usb_xfer *xfer, usb_error_t error)
{
        struct atp_softc      *sc = usbd_xfer_softc(xfer);
        int                    len;
        struct usb_page_cache *pc;
        uint8_t                status_bits;
        atp_pspan  pspans_x[ATP_MAX_PSPANS_PER_AXIS];
        atp_pspan  pspans_y[ATP_MAX_PSPANS_PER_AXIS];
        u_int      n_xpspans = 0, n_ypspans = 0;
        u_int      reaped_xlocs[ATP_MAX_STROKES];
        u_int      tap_fingers = 0;

        usbd_xfer_status(xfer, &len, NULL, NULL, NULL);

        switch (USB_GET_STATE(xfer)) {
        case USB_ST_TRANSFERRED:
                if (len > (int)sc->sc_params->data_len) {
                        DPRINTFN(ATP_LLEVEL_ERROR,
                            "truncating large packet from %u to %u bytes\n",
                            len, sc->sc_params->data_len);
                        len = sc->sc_params->data_len;
                }
                if (len < (int)sc->sc_params->data_len)
                        goto tr_setup;

                pc = usbd_xfer_get_frame(xfer, 0);
                usbd_copy_out(pc, 0, sc->sensor_data, sc->sc_params->data_len);

                /* Interpret sensor data */
                atp_interpret_sensor_data(sc->sensor_data,
                    sc->sc_params->n_xsensors, X, sc->cur_x,
                    sc->sc_params->prot);
                atp_interpret_sensor_data(sc->sensor_data,
                    sc->sc_params->n_ysensors, Y,  sc->cur_y,
                    sc->sc_params->prot);

                /*
                 * If this is the initial update (from an untouched
                 * pad), we should set the base values for the sensor
                 * data; deltas with respect to these base values can
                 * be used as pressure readings subsequently.
                 */
                status_bits = sc->sensor_data[sc->sc_params->data_len - 1];
                if ((sc->sc_params->prot == ATP_PROT_GEYSER3 &&
                    (status_bits & ATP_STATUS_BASE_UPDATE)) ||
                    !(sc->sc_state & ATP_VALID)) {
                        memcpy(sc->base_x, sc->cur_x,
                            sc->sc_params->n_xsensors * sizeof(*(sc->base_x)));
                        memcpy(sc->base_y, sc->cur_y,
                            sc->sc_params->n_ysensors * sizeof(*(sc->base_y)));
                        sc->sc_state |= ATP_VALID;
                        goto tr_setup;
                }

                /* Get pressure readings and detect p-spans for both axes. */
                atp_get_pressures(sc->pressure_x, sc->cur_x, sc->base_x,
                    sc->sc_params->n_xsensors);
                atp_detect_pspans(sc->pressure_x, sc->sc_params->n_xsensors,
                    ATP_MAX_PSPANS_PER_AXIS,
                    pspans_x, &n_xpspans);
                atp_get_pressures(sc->pressure_y, sc->cur_y, sc->base_y,
                    sc->sc_params->n_ysensors);
                atp_detect_pspans(sc->pressure_y, sc->sc_params->n_ysensors,
                    ATP_MAX_PSPANS_PER_AXIS,
                    pspans_y, &n_ypspans);

                /* Update strokes with new pspans to detect movements. */
                sc->sc_status.flags &= ~MOUSE_POSCHANGED;
                if (atp_update_strokes(sc,
                        pspans_x, n_xpspans,
                        pspans_y, n_ypspans))
                        sc->sc_status.flags |= MOUSE_POSCHANGED;

                /* Reap zombies if it is time. */
                if (sc->sc_state & ATP_ZOMBIES_EXIST) {
                        struct timeval now;

                        getmicrotime(&now);
                        if (timevalcmp(&now, &sc->sc_reap_time, >=))
                                atp_reap_zombies(sc, &tap_fingers,
                                    reaped_xlocs);
                }

                sc->sc_status.flags &= ~MOUSE_STDBUTTONSCHANGED;
                sc->sc_status.obutton = sc->sc_status.button;

                /* Get the state of the physical buttton. */
                sc->sc_status.button = (status_bits & ATP_STATUS_BUTTON) ?
                        MOUSE_BUTTON1DOWN : 0;
                if (sc->sc_status.button != 0) {
                        /* Reset DOUBLE_TAP_N_DRAG if the button is pressed. */
                        sc->sc_state &= ~ATP_DOUBLE_TAP_DRAG;
                } else if (sc->sc_state & ATP_DOUBLE_TAP_DRAG) {
                        /* Assume a button-press with DOUBLE_TAP_N_DRAG. */
                        sc->sc_status.button = MOUSE_BUTTON1DOWN;
                }

                sc->sc_status.flags |=
                        sc->sc_status.button ^ sc->sc_status.obutton;
                if (sc->sc_status.flags & MOUSE_STDBUTTONSCHANGED) {
                        DPRINTFN(ATP_LLEVEL_INFO, "button %s\n",
                            ((sc->sc_status.button & MOUSE_BUTTON1DOWN) ?
                                "pressed" : "released"));
                } else if ((sc->sc_status.obutton == 0) &&
                    (sc->sc_status.button == 0) &&
                    (tap_fingers != 0)) {
                        /* Ignore single-finger taps at the edges. */
                        if ((tap_fingers == 1) &&
                            ((reaped_xlocs[0] <= sc->sc_left_margin) ||
                                (reaped_xlocs[0] > sc->sc_right_margin))) {
                                tap_fingers = 0;
                        }
                        DPRINTFN(ATP_LLEVEL_INFO,
                            "tap_fingers: %u\n", tap_fingers);
                }

                if (sc->sc_status.flags &
                    (MOUSE_POSCHANGED | MOUSE_STDBUTTONSCHANGED)) {
                        int   dx, dy;
                        u_int n_movements;

                        dx = 0, dy = 0, n_movements = 0;
                        for (u_int i = 0; i < sc->sc_n_strokes; i++) {
                                atp_stroke *stroke = &sc->sc_strokes[i];

                                if ((stroke->components[X].movement) ||
                                    (stroke->components[Y].movement)) {
                                        dx += stroke->components[X].movement;
                                        dy += stroke->components[Y].movement;
                                        n_movements++;
                                }
                        }
                        /*
                         * Disregard movement if multiple
                         * strokes record motion.
                         */
                        if (n_movements != 1)
                                dx = 0, dy = 0;

                        sc->sc_status.dx += dx;
                        sc->sc_status.dy += dy;
                        atp_add_to_queue(sc, dx, -dy, sc->sc_status.button);
                }

                if (tap_fingers != 0) {
                        /* Add a pair of events (button-down and button-up). */
                        switch (tap_fingers) {
                        case 1: atp_add_to_queue(sc, 0, 0, MOUSE_BUTTON1DOWN);
                                break;
                        case 2: atp_add_to_queue(sc, 0, 0, MOUSE_BUTTON2DOWN);
                                break;
                        case 3: atp_add_to_queue(sc, 0, 0, MOUSE_BUTTON3DOWN);
                                break;
                        default: break;/* handle taps of only up to 3 fingers */
                        }
                        atp_add_to_queue(sc, 0, 0, 0); /* button release */
                }

                /*
                 * The device continues to trigger interrupts at a
                 * fast rate even after touchpad activity has
                 * stopped. Upon detecting that the device has
                 * remained idle beyond a threshold, we reinitialize
                 * it to silence the interrupts.
                 */
                if ((sc->sc_status.flags  == 0) &&
                    (sc->sc_n_strokes     == 0) &&
                    (sc->sc_status.button == 0)) {
                        sc->sc_idlecount++;
                        if (sc->sc_idlecount >= ATP_IDLENESS_THRESHOLD) {
                                DPRINTFN(ATP_LLEVEL_INFO, "idle\n");

                                /*
                                 * Use the last frame before we go idle for
                                 * calibration on pads which do not send
                                 * calibration frames.
                                 */
                                if (sc->sc_params->prot < ATP_PROT_GEYSER3) {
                                        memcpy(sc->base_x, sc->cur_x,
                                            sc->sc_params->n_xsensors *
                                            sizeof(*(sc->base_x)));
                                        memcpy(sc->base_y, sc->cur_y,
                                            sc->sc_params->n_ysensors *
                                            sizeof(*(sc->base_y)));
                                }

                                sc->sc_idlecount = 0;
                                usbd_transfer_start(sc->sc_xfer[ATP_RESET]);
                        }
                } else {
                        sc->sc_idlecount = 0;
                }

        case USB_ST_SETUP:
        tr_setup:
                /* check if we can put more data into the FIFO */
                if (usb_fifo_put_bytes_max(
                            sc->sc_fifo.fp[USB_FIFO_RX]) != 0) {
                        usbd_xfer_set_frame_len(xfer, 0,
                            sc->sc_params->data_len);
                        usbd_transfer_submit(xfer);
                }
                break;

        default:                        /* Error */
                if (error != USB_ERR_CANCELLED) {
                        /* try clear stall first */
                        usbd_xfer_set_stall(xfer);
                        goto tr_setup;
                }
                break;
        }

        return;
}

static void
atp_add_to_queue(struct atp_softc *sc, int dx, int dy, uint32_t buttons_in)
{
        uint32_t buttons_out;
        uint8_t  buf[8];

        dx = imin(dx,  254); dx = imax(dx, -256);
        dy = imin(dy,  254); dy = imax(dy, -256);

        buttons_out = MOUSE_MSC_BUTTONS;
        if (buttons_in & MOUSE_BUTTON1DOWN)
                buttons_out &= ~MOUSE_MSC_BUTTON1UP;
        else if (buttons_in & MOUSE_BUTTON2DOWN)
                buttons_out &= ~MOUSE_MSC_BUTTON2UP;
        else if (buttons_in & MOUSE_BUTTON3DOWN)
                buttons_out &= ~MOUSE_MSC_BUTTON3UP;

        DPRINTFN(ATP_LLEVEL_INFO, "dx=%d, dy=%d, buttons=%x\n",
            dx, dy, buttons_out);

        /* Encode the mouse data in standard format; refer to mouse(4) */
        buf[0] = sc->sc_mode.syncmask[1];
        buf[0] |= buttons_out;
        buf[1] = dx >> 1;
        buf[2] = dy >> 1;
        buf[3] = dx - (dx >> 1);
        buf[4] = dy - (dy >> 1);
        /* Encode extra bytes for level 1 */
        if (sc->sc_mode.level == 1) {
                buf[5] = 0;                    /* dz */
                buf[6] = 0;                    /* dz - (dz / 2) */
                buf[7] = MOUSE_SYS_EXTBUTTONS; /* Extra buttons all up. */
        }

        usb_fifo_put_data_linear(sc->sc_fifo.fp[USB_FIFO_RX], buf,
            sc->sc_mode.packetsize, 1);
}

static void
atp_reset_buf(struct atp_softc *sc)
{
        /* reset read queue */
        usb_fifo_reset(sc->sc_fifo.fp[USB_FIFO_RX]);
}

static void
atp_start_read(struct usb_fifo *fifo)
{
        struct atp_softc *sc = usb_fifo_softc(fifo);
        int rate;

        /* Check if we should override the default polling interval */
        rate = sc->sc_pollrate;
        /* Range check rate */
        if (rate > 1000)
                rate = 1000;
        /* Check for set rate */
        if ((rate > 0) && (sc->sc_xfer[ATP_INTR_DT] != NULL)) {
                /* Stop current transfer, if any */
                usbd_transfer_stop(sc->sc_xfer[ATP_INTR_DT]);
                /* Set new interval */
                usbd_xfer_set_interval(sc->sc_xfer[ATP_INTR_DT], 1000 / rate);
                /* Only set pollrate once */
                sc->sc_pollrate = 0;
        }

        usbd_transfer_start(sc->sc_xfer[ATP_INTR_DT]);
}

static void
atp_stop_read(struct usb_fifo *fifo)
{
        struct atp_softc *sc = usb_fifo_softc(fifo);

        usbd_transfer_stop(sc->sc_xfer[ATP_INTR_DT]);
}


static int
atp_open(struct usb_fifo *fifo, int fflags)
{
        DPRINTFN(ATP_LLEVEL_INFO, "\n");

        if (fflags & FREAD) {
                struct atp_softc *sc = usb_fifo_softc(fifo);
                int rc;

                if (sc->sc_state & ATP_ENABLED)
                        return (EBUSY);

                if (usb_fifo_alloc_buffer(fifo,
                        ATP_FIFO_BUF_SIZE, ATP_FIFO_QUEUE_MAXLEN)) {
                        return (ENOMEM);
                }

                rc = atp_enable(sc);
                if (rc != 0) {
                        usb_fifo_free_buffer(fifo);
                        return (rc);
                }
        }

        return (0);
}

static void
atp_close(struct usb_fifo *fifo, int fflags)
{
        if (fflags & FREAD) {
                struct atp_softc *sc = usb_fifo_softc(fifo);

                atp_disable(sc);
                usb_fifo_free_buffer(fifo);
        }
}

int
atp_ioctl(struct usb_fifo *fifo, u_long cmd, void *addr, int fflags)
{
        struct atp_softc *sc = usb_fifo_softc(fifo);
        mousemode_t mode;
        int error = 0;

        mtx_lock(&sc->sc_mutex);

        switch(cmd) {
        case MOUSE_GETHWINFO:
                *(mousehw_t *)addr = sc->sc_hw;
                break;
        case MOUSE_GETMODE:
                *(mousemode_t *)addr = sc->sc_mode;
                break;
        case MOUSE_SETMODE:
                mode = *(mousemode_t *)addr;

                if (mode.level == -1)
                        /* Don't change the current setting */
                        ;
                else if ((mode.level < 0) || (mode.level > 1)) {
                        error = EINVAL;
                        goto done;
                }
                sc->sc_mode.level = mode.level;
                sc->sc_pollrate   = mode.rate;
                sc->sc_hw.buttons = 3;

                if (sc->sc_mode.level == 0) {
                        sc->sc_mode.protocol = MOUSE_PROTO_MSC;
                        sc->sc_mode.packetsize = MOUSE_MSC_PACKETSIZE;
                        sc->sc_mode.syncmask[0] = MOUSE_MSC_SYNCMASK;
                        sc->sc_mode.syncmask[1] = MOUSE_MSC_SYNC;
                } else if (sc->sc_mode.level == 1) {
                        sc->sc_mode.protocol = MOUSE_PROTO_SYSMOUSE;
                        sc->sc_mode.packetsize = MOUSE_SYS_PACKETSIZE;
                        sc->sc_mode.syncmask[0] = MOUSE_SYS_SYNCMASK;
                        sc->sc_mode.syncmask[1] = MOUSE_SYS_SYNC;
                }
                atp_reset_buf(sc);
                break;
        case MOUSE_GETLEVEL:
                *(int *)addr = sc->sc_mode.level;
                break;
        case MOUSE_SETLEVEL:
                if (*(int *)addr < 0 || *(int *)addr > 1) {
                        error = EINVAL;
                        goto done;
                }
                sc->sc_mode.level = *(int *)addr;
                sc->sc_hw.buttons = 3;

                if (sc->sc_mode.level == 0) {
                        sc->sc_mode.protocol = MOUSE_PROTO_MSC;
                        sc->sc_mode.packetsize = MOUSE_MSC_PACKETSIZE;
                        sc->sc_mode.syncmask[0] = MOUSE_MSC_SYNCMASK;
                        sc->sc_mode.syncmask[1] = MOUSE_MSC_SYNC;
                } else if (sc->sc_mode.level == 1) {
                        sc->sc_mode.protocol = MOUSE_PROTO_SYSMOUSE;
                        sc->sc_mode.packetsize = MOUSE_SYS_PACKETSIZE;
                        sc->sc_mode.syncmask[0] = MOUSE_SYS_SYNCMASK;
                        sc->sc_mode.syncmask[1] = MOUSE_SYS_SYNC;
                }
                atp_reset_buf(sc);
                break;
        case MOUSE_GETSTATUS: {
                mousestatus_t *status = (mousestatus_t *)addr;

                *status = sc->sc_status;
                sc->sc_status.obutton = sc->sc_status.button;
                sc->sc_status.button  = 0;
                sc->sc_status.dx = 0;
                sc->sc_status.dy = 0;
                sc->sc_status.dz = 0;

                if (status->dx || status->dy || status->dz)
                        status->flags |= MOUSE_POSCHANGED;
                if (status->button != status->obutton)
                        status->flags |= MOUSE_BUTTONSCHANGED;
                break;
        }
        default:
                error = ENOTTY;
        }

done:
        mtx_unlock(&sc->sc_mutex);
        return (error);
}

static int
atp_sysctl_scale_factor_handler(SYSCTL_HANDLER_ARGS)
{
        int error;
        u_int tmp;
        u_int prev_mickeys_scale_factor;

        prev_mickeys_scale_factor = atp_mickeys_scale_factor;

        tmp = atp_mickeys_scale_factor;
        error = sysctl_handle_int(oidp, &tmp, 0, req);
        if (error != 0 || req->newptr == NULL)
                return (error);

        if (tmp == prev_mickeys_scale_factor)
                return (0);     /* no change */

        atp_mickeys_scale_factor = tmp;
        DPRINTFN(ATP_LLEVEL_INFO, "%s: resetting mickeys_scale_factor to %u\n",
            ATP_DRIVER_NAME, tmp);

        /* Update dependent thresholds. */
        if (atp_small_movement_threshold == (prev_mickeys_scale_factor >> 3))
                atp_small_movement_threshold = atp_mickeys_scale_factor >> 3;
        if (atp_max_delta_mickeys == ((3 * prev_mickeys_scale_factor) >> 1))
                atp_max_delta_mickeys = ((3 * atp_mickeys_scale_factor) >>1);
        if (atp_slide_min_movement == (prev_mickeys_scale_factor >> 3))
                atp_slide_min_movement = atp_mickeys_scale_factor >> 3;

        return (0);
}

static device_method_t atp_methods[] = {
        /* Device interface */
        DEVMETHOD(device_probe,  atp_probe),
        DEVMETHOD(device_attach, atp_attach),
        DEVMETHOD(device_detach, atp_detach),
        { 0, 0 }
};

static driver_t atp_driver = {
        .name = ATP_DRIVER_NAME,
        .methods = atp_methods,
        .size = sizeof(struct atp_softc)
};

static devclass_t atp_devclass;

DRIVER_MODULE(atp, uhub, atp_driver, atp_devclass, NULL, 0);
MODULE_DEPEND(atp, usb, 1, 1, 1);
MODULE_VERSION(atp, 1);