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freebsd-dev/sys/dev/usb/usb_hid.c
Vladimir Kondratyev 99a4d2ce08 Raise "Report Count" value limit in HID descriptor parser. 
This fixes usage/report size calculation of Microsoft`s "Touch Hardware
Quality Assurance" certificate blob found in many touchscreens.

While here, join several "c->flags = dval" lines in to single line.

Reviewed by:	hselasky
MFC after:	2 weeks
Differential Revision:	https://reviews.freebsd.org/D16357
2018-07-21 14:20:17 +00:00

1002 lines
23 KiB
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/* $FreeBSD$ */
/* $NetBSD: hid.c,v 1.17 2001/11/13 06:24:53 lukem Exp $ */
/*-
* SPDX-License-Identifier: BSD-2-Clause-NetBSD
*
* 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.
*/
#ifdef USB_GLOBAL_INCLUDE_FILE
#include USB_GLOBAL_INCLUDE_FILE
#else
#include <sys/stdint.h>
#include <sys/stddef.h>
#include <sys/param.h>
#include <sys/queue.h>
#include <sys/types.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/bus.h>
#include <sys/module.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/condvar.h>
#include <sys/sysctl.h>
#include <sys/sx.h>
#include <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>
#endif /* USB_GLOBAL_INCLUDE_FILE */
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
#define MAXLOCCNT 1024
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 */
uint32_t ncount; /* end usage item count */
uint32_t icount; /* current usage item count */
uint8_t kindset; /* we have 5 kinds so 8 bits are enough */
uint8_t pushlevel; /* current pushlevel */
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;
ret:
c->flags = dval;
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 > MAXLOCCNT) {
DPRINTFN(0, "Number of "
"items(%u) truncated to %u\n",
(unsigned)(c->loc.count),
MAXLOCCNT);
s->ncount = MAXLOCCNT;
} 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;
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;
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 presence */
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);
}
/*------------------------------------------------------------------------*
* calculate HID item resolution. unit/mm for distances, unit/rad for angles
*------------------------------------------------------------------------*/
int32_t
hid_item_resolution(struct hid_item *hi)
{
/*
* hid unit scaling table according to HID Usage Table Review
* Request 39 Tbl 17 http://www.usb.org/developers/hidpage/HUTRR39b.pdf
*/
static const int64_t scale[0x10][2] = {
[0x00] = { 1, 1 },
[0x01] = { 1, 10 },
[0x02] = { 1, 100 },
[0x03] = { 1, 1000 },
[0x04] = { 1, 10000 },
[0x05] = { 1, 100000 },
[0x06] = { 1, 1000000 },
[0x07] = { 1, 10000000 },
[0x08] = { 100000000, 1 },
[0x09] = { 10000000, 1 },
[0x0A] = { 1000000, 1 },
[0x0B] = { 100000, 1 },
[0x0C] = { 10000, 1 },
[0x0D] = { 1000, 1 },
[0x0E] = { 100, 1 },
[0x0F] = { 10, 1 },
};
int64_t logical_size;
int64_t physical_size;
int64_t multiplier;
int64_t divisor;
int64_t resolution;
switch (hi->unit) {
case HUM_CENTIMETER:
multiplier = 1;
divisor = 10;
break;
case HUM_INCH:
multiplier = 10;
divisor = 254;
break;
case HUM_RADIAN:
multiplier = 1;
divisor = 1;
break;
case HUM_DEGREE:
multiplier = 573;
divisor = 10;
break;
default:
return (0);
}
if ((hi->logical_maximum <= hi->logical_minimum) ||
(hi->physical_maximum <= hi->physical_minimum) ||
(hi->unit_exponent < 0) || (hi->unit_exponent >= nitems(scale)))
return (0);
logical_size = (int64_t)hi->logical_maximum -
(int64_t)hi->logical_minimum;
physical_size = (int64_t)hi->physical_maximum -
(int64_t)hi->physical_minimum;
/* Round to ceiling */
resolution = logical_size * multiplier * scale[hi->unit_exponent][0] /
(physical_size * divisor * scale[hi->unit_exponent][1]);
if (resolution > INT32_MAX)
return (0);
return (resolution);
}
/*------------------------------------------------------------------------*
* 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);
}
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