source: rtems-libbsd/freebsd/sys/dev/usb/usb_hid.c @ 66659ff

#include <machine/rtems-bsd-kernel-space.h>

/*      $NetBSD: hid.c,v 1.17 2001/11/13 06:24:53 lukem Exp $   */


#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
/*-
 * Copyright (c) 1998 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Lennart Augustsson (lennart@augustsson.net) at
 * Carlstedt Research & Technology.
 *
 * 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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/stdint.h>
#include <sys/stddef.h>
#include <rtems/bsd/sys/param.h>
#include <sys/queue.h>
#include <rtems/bsd/sys/types.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/bus.h>
#include <sys/module.h>
#include <rtems/bsd/sys/lock.h>
#include <sys/mutex.h>
#include <sys/condvar.h>
#include <sys/sysctl.h>
#include <sys/sx.h>
#include <rtems/bsd/sys/unistd.h>
#include <sys/callout.h>
#include <sys/malloc.h>
#include <sys/priv.h>

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

#define USB_DEBUG_VAR usb_debug

#include <dev/usb/usb_core.h>
#include <dev/usb/usb_debug.h>
#include <dev/usb/usb_process.h>
#include <dev/usb/usb_device.h>
#include <dev/usb/usb_request.h>

static void hid_clear_local(struct hid_item *);
static uint8_t hid_get_byte(struct hid_data *s, const uint16_t wSize);

#define MAXUSAGE 64
#define MAXPUSH 4
#define MAXID 16

struct hid_pos_data {
        int32_t rid;
        uint32_t pos;
};

struct hid_data {
        const uint8_t *start;
        const uint8_t *end;
        const uint8_t *p;
        struct hid_item cur[MAXPUSH];
        struct hid_pos_data last_pos[MAXID];
        int32_t usages_min[MAXUSAGE];
        int32_t usages_max[MAXUSAGE];
        int32_t usage_last;     /* last seen usage */
        uint32_t loc_size;      /* last seen size */
        uint32_t loc_count;     /* last seen count */
        uint8_t kindset;        /* we have 5 kinds so 8 bits are enough */
        uint8_t pushlevel;      /* current pushlevel */
        uint8_t ncount;         /* end usage item count */
        uint8_t icount;         /* current usage item count */
        uint8_t nusage;         /* end "usages_min/max" index */
        uint8_t iusage;         /* current "usages_min/max" index */
        uint8_t ousage;         /* current "usages_min/max" offset */
        uint8_t susage;         /* usage set flags */
};

/*------------------------------------------------------------------------*
 *      hid_clear_local
 *------------------------------------------------------------------------*/
static void
hid_clear_local(struct hid_item *c)
{

        c->loc.count = 0;
        c->loc.size = 0;
        c->usage = 0;
        c->usage_minimum = 0;
        c->usage_maximum = 0;
        c->designator_index = 0;
        c->designator_minimum = 0;
        c->designator_maximum = 0;
        c->string_index = 0;
        c->string_minimum = 0;
        c->string_maximum = 0;
        c->set_delimiter = 0;
}

static void
hid_switch_rid(struct hid_data *s, struct hid_item *c, int32_t next_rID)
{
        uint8_t i;

        /* check for same report ID - optimise */

        if (c->report_ID == next_rID)
                return;

        /* save current position for current rID */

        if (c->report_ID == 0) {
                i = 0;
        } else {
                for (i = 1; i != MAXID; i++) {
                        if (s->last_pos[i].rid == c->report_ID)
                                break;
                        if (s->last_pos[i].rid == 0)
                                break;
                }
        }
        if (i != MAXID) {
                s->last_pos[i].rid = c->report_ID;
                s->last_pos[i].pos = c->loc.pos;
        }

        /* store next report ID */

        c->report_ID = next_rID;

        /* lookup last position for next rID */

        if (next_rID == 0) {
                i = 0;
        } else {
                for (i = 1; i != MAXID; i++) {
                        if (s->last_pos[i].rid == next_rID)
                                break;
                        if (s->last_pos[i].rid == 0)
                                break;
                }
        }
        if (i != MAXID) {
                s->last_pos[i].rid = next_rID;
                c->loc.pos = s->last_pos[i].pos;
        } else {
                DPRINTF("Out of RID entries, position is set to zero!\n");
                c->loc.pos = 0;
        }
}

/*------------------------------------------------------------------------*
 *      hid_start_parse
 *------------------------------------------------------------------------*/
struct hid_data *
hid_start_parse(const void *d, usb_size_t len, int kindset)
{
        struct hid_data *s;

        if ((kindset-1) & kindset) {
                DPRINTFN(0, "Only one bit can be "
                    "set in the kindset\n");
                return (NULL);
        }

        s = malloc(sizeof *s, M_TEMP, M_WAITOK | M_ZERO);
        s->start = s->p = d;
        s->end = ((const uint8_t *)d) + len;
        s->kindset = kindset;
        return (s);
}

/*------------------------------------------------------------------------*
 *      hid_end_parse
 *------------------------------------------------------------------------*/
void
hid_end_parse(struct hid_data *s)
{
        if (s == NULL)
                return;

        free(s, M_TEMP);
}

/*------------------------------------------------------------------------*
 *      get byte from HID descriptor
 *------------------------------------------------------------------------*/
static uint8_t
hid_get_byte(struct hid_data *s, const uint16_t wSize)
{
        const uint8_t *ptr;
        uint8_t retval;

        ptr = s->p;

        /* check if end is reached */
        if (ptr == s->end)
                return (0);

        /* read out a byte */
        retval = *ptr;

        /* check if data pointer can be advanced by "wSize" bytes */
        if ((s->end - ptr) < wSize)
                ptr = s->end;
        else
                ptr += wSize;

        /* update pointer */
        s->p = ptr;

        return (retval);
}

/*------------------------------------------------------------------------*
 *      hid_get_item
 *------------------------------------------------------------------------*/
int
hid_get_item(struct hid_data *s, struct hid_item *h)
{
        struct hid_item *c;
        unsigned int bTag, bType, bSize;
        uint32_t oldpos;
        int32_t mask;
        int32_t dval;

        if (s == NULL)
                return (0);

        c = &s->cur[s->pushlevel];

 top:
        /* check if there is an array of items */
        if (s->icount < s->ncount) {
                /* get current usage */
                if (s->iusage < s->nusage) {
                        dval = s->usages_min[s->iusage] + s->ousage;
                        c->usage = dval;
                        s->usage_last = dval;
                        if (dval == s->usages_max[s->iusage]) {
                                s->iusage ++;
                                s->ousage = 0;
                        } else {
                                s->ousage ++;
                        }
                } else {
                        DPRINTFN(1, "Using last usage\n");
                        dval = s->usage_last;
                }
                s->icount ++;
                /* 
                 * Only copy HID item, increment position and return
                 * if correct kindset!
                 */
                if (s->kindset & (1 << c->kind)) {
                        *h = *c;
                        DPRINTFN(1, "%u,%u,%u\n", h->loc.pos,
                            h->loc.size, h->loc.count);
                        c->loc.pos += c->loc.size * c->loc.count;
                        return (1);
                }
        }

        /* reset state variables */
        s->icount = 0;
        s->ncount = 0;
        s->iusage = 0;
        s->nusage = 0;
        s->susage = 0;
        s->ousage = 0;
        hid_clear_local(c);

        /* get next item */
        while (s->p != s->end) {

                bSize = hid_get_byte(s, 1);
                if (bSize == 0xfe) {
                        /* long item */
                        bSize = hid_get_byte(s, 1);
                        bSize |= hid_get_byte(s, 1) << 8;
                        bTag = hid_get_byte(s, 1);
                        bType = 0xff;   /* XXX what should it be */
                } else {
                        /* short item */
                        bTag = bSize >> 4;
                        bType = (bSize >> 2) & 3;
                        bSize &= 3;
                        if (bSize == 3)
                                bSize = 4;
                }
                switch (bSize) {
                case 0:
                        dval = 0;
                        mask = 0;
                        break;
                case 1:
                        dval = (int8_t)hid_get_byte(s, 1);
                        mask = 0xFF;
                        break;
                case 2:
                        dval = hid_get_byte(s, 1);
                        dval |= hid_get_byte(s, 1) << 8;
                        dval = (int16_t)dval;
                        mask = 0xFFFF;
                        break;
                case 4:
                        dval = hid_get_byte(s, 1);
                        dval |= hid_get_byte(s, 1) << 8;
                        dval |= hid_get_byte(s, 1) << 16;
                        dval |= hid_get_byte(s, 1) << 24;
                        mask = 0xFFFFFFFF;
                        break;
                default:
                        dval = hid_get_byte(s, bSize);
                        DPRINTFN(0, "bad length %u (data=0x%02x)\n",
                            bSize, dval);
                        continue;
                }

                switch (bType) {
                case 0:         /* Main */
                        switch (bTag) {
                        case 8: /* Input */
                                c->kind = hid_input;
                                c->flags = dval;
                ret:
                                c->loc.count = s->loc_count;
                                c->loc.size = s->loc_size;

                                if (c->flags & HIO_VARIABLE) {
                                        /* range check usage count */
                                        if (c->loc.count > 255) {
                                                DPRINTFN(0, "Number of "
                                                    "items truncated to 255\n");
                                                s->ncount = 255;
                                        } else
                                                s->ncount = c->loc.count;

                                        /* 
                                         * The "top" loop will return
                                         * one and one item:
                                         */
                                        c->loc.count = 1;
                                } else {
                                        s->ncount = 1;
                                }
                                goto top;

                        case 9: /* Output */
                                c->kind = hid_output;
                                c->flags = dval;
                                goto ret;
                        case 10:        /* Collection */
                                c->kind = hid_collection;
                                c->collection = dval;
                                c->collevel++;
                                c->usage = s->usage_last;
                                *h = *c;
                                return (1);
                        case 11:        /* Feature */
                                c->kind = hid_feature;
                                c->flags = dval;
                                goto ret;
                        case 12:        /* End collection */
                                c->kind = hid_endcollection;
                                if (c->collevel == 0) {
                                        DPRINTFN(0, "invalid end collection\n");
                                        return (0);
                                }
                                c->collevel--;
                                *h = *c;
                                return (1);
                        default:
                                DPRINTFN(0, "Main bTag=%d\n", bTag);
                                break;
                        }
                        break;
                case 1:         /* Global */
                        switch (bTag) {
                        case 0:
                                c->_usage_page = dval << 16;
                                break;
                        case 1:
                                c->logical_minimum = dval;
                                break;
                        case 2:
                                c->logical_maximum = dval;
                                break;
                        case 3:
                                c->physical_minimum = dval;
                                break;
                        case 4:
                                c->physical_maximum = dval;
                                break;
                        case 5:
                                c->unit_exponent = dval;
                                break;
                        case 6:
                                c->unit = dval;
                                break;
                        case 7:
                                /* mask because value is unsigned */
                                s->loc_size = dval & mask;
                                break;
                        case 8:
                                hid_switch_rid(s, c, dval & mask);
                                break;
                        case 9:
                                /* mask because value is unsigned */
                                s->loc_count = dval & mask;
                                break;
                        case 10:        /* Push */
                                s->pushlevel ++;
                                if (s->pushlevel < MAXPUSH) {
                                        s->cur[s->pushlevel] = *c;
                                        /* store size and count */
                                        c->loc.size = s->loc_size;
                                        c->loc.count = s->loc_count;
                                        /* update current item pointer */
                                        c = &s->cur[s->pushlevel];
                                } else {
                                        DPRINTFN(0, "Cannot push "
                                            "item @ %d\n", s->pushlevel);
                                }
                                break;
                        case 11:        /* Pop */
                                s->pushlevel --;
                                if (s->pushlevel < MAXPUSH) {
                                        /* preserve position */
                                        oldpos = c->loc.pos;
                                        c = &s->cur[s->pushlevel];
                                        /* restore size and count */
                                        s->loc_size = c->loc.size;
                                        s->loc_count = c->loc.count;
                                        /* set default item location */
                                        c->loc.pos = oldpos;
                                        c->loc.size = 0;
                                        c->loc.count = 0;
                                } else {
                                        DPRINTFN(0, "Cannot pop "
                                            "item @ %d\n", s->pushlevel);
                                }
                                break;
                        default:
                                DPRINTFN(0, "Global bTag=%d\n", bTag);
                                break;
                        }
                        break;
                case 2:         /* Local */
                        switch (bTag) {
                        case 0:
                                if (bSize != 4)
                                        dval = (dval & mask) | c->_usage_page;

                                /* set last usage, in case of a collection */
                                s->usage_last = dval;

                                if (s->nusage < MAXUSAGE) {
                                        s->usages_min[s->nusage] = dval;
                                        s->usages_max[s->nusage] = dval;
                                        s->nusage ++;
                                } else {
                                        DPRINTFN(0, "max usage reached\n");
                                }

                                /* clear any pending usage sets */
                                s->susage = 0;
                                break;
                        case 1:
                                s->susage |= 1;

                                if (bSize != 4)
                                        dval = (dval & mask) | c->_usage_page;
                                c->usage_minimum = dval;

                                goto check_set;
                        case 2:
                                s->susage |= 2;

                                if (bSize != 4)
                                        dval = (dval & mask) | c->_usage_page;
                                c->usage_maximum = dval;

                        check_set:
                                if (s->susage != 3)
                                        break;

                                /* sanity check */
                                if ((s->nusage < MAXUSAGE) &&
                                    (c->usage_minimum <= c->usage_maximum)) {
                                        /* add usage range */
                                        s->usages_min[s->nusage] = 
                                            c->usage_minimum;
                                        s->usages_max[s->nusage] = 
                                            c->usage_maximum;
                                        s->nusage ++;
                                } else {
                                        DPRINTFN(0, "Usage set dropped\n");
                                }
                                s->susage = 0;
                                break;
                        case 3:
                                c->designator_index = dval;
                                break;
                        case 4:
                                c->designator_minimum = dval;
                                break;
                        case 5:
                                c->designator_maximum = dval;
                                break;
                        case 7:
                                c->string_index = dval;
                                break;
                        case 8:
                                c->string_minimum = dval;
                                break;
                        case 9:
                                c->string_maximum = dval;
                                break;
                        case 10:
                                c->set_delimiter = dval;
                                break;
                        default:
                                DPRINTFN(0, "Local bTag=%d\n", bTag);
                                break;
                        }
                        break;
                default:
                        DPRINTFN(0, "default bType=%d\n", bType);
                        break;
                }
        }
        return (0);
}

/*------------------------------------------------------------------------*
 *      hid_report_size
 *------------------------------------------------------------------------*/
int
hid_report_size(const void *buf, usb_size_t len, enum hid_kind k, uint8_t *id)
{
        struct hid_data *d;
        struct hid_item h;
        uint32_t temp;
        uint32_t hpos;
        uint32_t lpos;
        uint8_t any_id;

        any_id = 0;
        hpos = 0;
        lpos = 0xFFFFFFFF;

        for (d = hid_start_parse(buf, len, 1 << k); hid_get_item(d, &h);) {
                if (h.kind == k) {
                        /* check for ID-byte presense */
                        if ((h.report_ID != 0) && !any_id) {
                                if (id != NULL)
                                        *id = h.report_ID;
                                any_id = 1;
                        }
                        /* compute minimum */
                        if (lpos > h.loc.pos)
                                lpos = h.loc.pos;
                        /* compute end position */
                        temp = h.loc.pos + (h.loc.size * h.loc.count);
                        /* compute maximum */
                        if (hpos < temp)
                                hpos = temp;
                }
        }
        hid_end_parse(d);

        /* safety check - can happen in case of currupt descriptors */
        if (lpos > hpos)
                temp = 0;
        else
                temp = hpos - lpos;

        /* check for ID byte */
        if (any_id)
                temp += 8;
        else if (id != NULL)
                *id = 0;

        /* return length in bytes rounded up */
        return ((temp + 7) / 8);
}

/*------------------------------------------------------------------------*
 *      hid_locate
 *------------------------------------------------------------------------*/
int
hid_locate(const void *desc, usb_size_t size, int32_t u, enum hid_kind k,
    uint8_t index, struct hid_location *loc, uint32_t *flags, uint8_t *id)
{
        struct hid_data *d;
        struct hid_item h;

        for (d = hid_start_parse(desc, size, 1 << k); hid_get_item(d, &h);) {
                if (h.kind == k && !(h.flags & HIO_CONST) && h.usage == u) {
                        if (index--)
                                continue;
                        if (loc != NULL)
                                *loc = h.loc;
                        if (flags != NULL)
                                *flags = h.flags;
                        if (id != NULL)
                                *id = h.report_ID;
                        hid_end_parse(d);
                        return (1);
                }
        }
        if (loc != NULL)
                loc->size = 0;
        if (flags != NULL)
                *flags = 0;
        if (id != NULL)
                *id = 0;
        hid_end_parse(d);
        return (0);
}

/*------------------------------------------------------------------------*
 *      hid_get_data
 *------------------------------------------------------------------------*/
static uint32_t
hid_get_data_sub(const uint8_t *buf, usb_size_t len, struct hid_location *loc,
    int is_signed)
{
        uint32_t hpos = loc->pos;
        uint32_t hsize = loc->size;
        uint32_t data;
        uint32_t rpos;
        uint8_t n;

        DPRINTFN(11, "hid_get_data: loc %d/%d\n", hpos, hsize);

        /* Range check and limit */
        if (hsize == 0)
                return (0);
        if (hsize > 32)
                hsize = 32;

        /* Get data in a safe way */    
        data = 0;
        rpos = (hpos / 8);
        n = (hsize + 7) / 8;
        rpos += n;
        while (n--) {
                rpos--;
                if (rpos < len)
                        data |= buf[rpos] << (8 * n);
        }

        /* Correctly shift down data */
        data = (data >> (hpos % 8));
        n = 32 - hsize;

        /* Mask and sign extend in one */
        if (is_signed != 0)
                data = (int32_t)((int32_t)data << n) >> n;
        else
                data = (uint32_t)((uint32_t)data << n) >> n;

        DPRINTFN(11, "hid_get_data: loc %d/%d = %lu\n",
            loc->pos, loc->size, (long)data);
        return (data);
}

int32_t
hid_get_data(const uint8_t *buf, usb_size_t len, struct hid_location *loc)
{
        return (hid_get_data_sub(buf, len, loc, 1));
}

uint32_t
hid_get_data_unsigned(const uint8_t *buf, usb_size_t len, struct hid_location *loc)
{
        return (hid_get_data_sub(buf, len, loc, 0));
}

/*------------------------------------------------------------------------*
 *      hid_put_data
 *------------------------------------------------------------------------*/
void
hid_put_data_unsigned(uint8_t *buf, usb_size_t len,
    struct hid_location *loc, unsigned int value)
{
        uint32_t hpos = loc->pos;
        uint32_t hsize = loc->size;
        uint64_t data;
        uint64_t mask;
        uint32_t rpos;
        uint8_t n;

        DPRINTFN(11, "hid_put_data: loc %d/%d = %u\n", hpos, hsize, value);

        /* Range check and limit */
        if (hsize == 0)
                return;
        if (hsize > 32)
                hsize = 32;

        /* Put data in a safe way */    
        rpos = (hpos / 8);
        n = (hsize + 7) / 8;
        data = ((uint64_t)value) << (hpos % 8);
        mask = ((1ULL << hsize) - 1ULL) << (hpos % 8);
        rpos += n;
        while (n--) {
                rpos--;
                if (rpos < len) {
                        buf[rpos] &= ~(mask >> (8 * n));
                        buf[rpos] |= (data >> (8 * n));
                }
        }
}

/*------------------------------------------------------------------------*
 *      hid_is_collection
 *------------------------------------------------------------------------*/
int
hid_is_collection(const void *desc, usb_size_t size, int32_t usage)
{
        struct hid_data *hd;
        struct hid_item hi;
        int err;

        hd = hid_start_parse(desc, size, hid_input);
        if (hd == NULL)
                return (0);

        while ((err = hid_get_item(hd, &hi))) {
                 if (hi.kind == hid_collection &&
                     hi.usage == usage)
                        break;
        }
        hid_end_parse(hd);
        return (err);
}

/*------------------------------------------------------------------------*
 *      hid_get_descriptor_from_usb
 *
 * This function will search for a HID descriptor between two USB
 * interface descriptors.
 *
 * Return values:
 * NULL: No more HID descriptors.
 * Else: Pointer to HID descriptor.
 *------------------------------------------------------------------------*/
struct usb_hid_descriptor *
hid_get_descriptor_from_usb(struct usb_config_descriptor *cd,
    struct usb_interface_descriptor *id)
{
        struct usb_descriptor *desc = (void *)id;

        if (desc == NULL) {
                return (NULL);
        }
        while ((desc = usb_desc_foreach(cd, desc))) {
                if ((desc->bDescriptorType == UDESC_HID) &&
                    (desc->bLength >= USB_HID_DESCRIPTOR_SIZE(0))) {
                        return (void *)desc;
                }
                if (desc->bDescriptorType == UDESC_INTERFACE) {
                        break;
                }
        }
        return (NULL);
}

/*------------------------------------------------------------------------*
 *      usbd_req_get_hid_desc
 *
 * This function will read out an USB report descriptor from the USB
 * device.
 *
 * Return values:
 * NULL: Failure.
 * Else: Success. The pointer should eventually be passed to free().
 *------------------------------------------------------------------------*/
usb_error_t
usbd_req_get_hid_desc(struct usb_device *udev, struct mtx *mtx,
    void **descp, uint16_t *sizep,
    struct malloc_type *mem, uint8_t iface_index)
{
        struct usb_interface *iface = usbd_get_iface(udev, iface_index);
        struct usb_hid_descriptor *hid;
        usb_error_t err;

        if ((iface == NULL) || (iface->idesc == NULL)) {
                return (USB_ERR_INVAL);
        }
        hid = hid_get_descriptor_from_usb
            (usbd_get_config_descriptor(udev), iface->idesc);

        if (hid == NULL) {
                return (USB_ERR_IOERROR);
        }
        *sizep = UGETW(hid->descrs[0].wDescriptorLength);
        if (*sizep == 0) {
                return (USB_ERR_IOERROR);
        }
        if (mtx)
                mtx_unlock(mtx);

        *descp = malloc(*sizep, mem, M_ZERO | M_WAITOK);

        if (mtx)
                mtx_lock(mtx);

        if (*descp == NULL) {
                return (USB_ERR_NOMEM);
        }
        err = usbd_req_get_report_descriptor
            (udev, mtx, *descp, *sizep, iface_index);

        if (err) {
                free(*descp, mem);
                *descp = NULL;
                return (err);
        }
        return (USB_ERR_NORMAL_COMPLETION);
}

/*------------------------------------------------------------------------*
 *      hid_is_mouse
 *
 * This function will decide if a USB descriptor belongs to a USB mouse.
 *
 * Return values:
 * Zero: Not a USB mouse.
 * Else: Is a USB mouse.
 *------------------------------------------------------------------------*/
int
hid_is_mouse(const void *d_ptr, uint16_t d_len)
{
        struct hid_data *hd;
        struct hid_item hi;
        int mdepth;
        int found;

        hd = hid_start_parse(d_ptr, d_len, 1 << hid_input);
        if (hd == NULL)
                return (0);

        mdepth = 0;
        found = 0;

        while (hid_get_item(hd, &hi)) {
                switch (hi.kind) {
                case hid_collection:
                        if (mdepth != 0)
                                mdepth++;
                        else if (hi.collection == 1 &&
                             hi.usage ==
                              HID_USAGE2(HUP_GENERIC_DESKTOP, HUG_MOUSE))
                                mdepth++;
                        break;
                case hid_endcollection:
                        if (mdepth != 0)
                                mdepth--;
                        break;
                case hid_input:
                        if (mdepth == 0)
                                break;
                        if (hi.usage ==
                             HID_USAGE2(HUP_GENERIC_DESKTOP, HUG_X) &&
                            (hi.flags & (HIO_CONST|HIO_RELATIVE)) == HIO_RELATIVE)
                                found++;
                        if (hi.usage ==
                             HID_USAGE2(HUP_GENERIC_DESKTOP, HUG_Y) &&
                            (hi.flags & (HIO_CONST|HIO_RELATIVE)) == HIO_RELATIVE)
                                found++;
                        break;
                default:
                        break;
                }
        }
        hid_end_parse(hd);
        return (found);
}

/*------------------------------------------------------------------------*
 *      hid_is_keyboard
 *
 * This function will decide if a USB descriptor belongs to a USB keyboard.
 *
 * Return values:
 * Zero: Not a USB keyboard.
 * Else: Is a USB keyboard.
 *------------------------------------------------------------------------*/
int
hid_is_keyboard(const void *d_ptr, uint16_t d_len)
{
        if (hid_is_collection(d_ptr, d_len,
            HID_USAGE2(HUP_GENERIC_DESKTOP, HUG_KEYBOARD)))
                return (1);
        return (0);
}