sys/dev/usb/usb_hid.c

   1 /*      $NetBSD: hid.c,v 1.17 2001/11/13 06:24:53 lukem Exp $   */
   2
   3
   4 #include <sys/cdefs.h>
   5 __FBSDID("$FreeBSD$");
   6 /*-
   7  * Copyright (c) 1998 The NetBSD Foundation, Inc.
   8  * All rights reserved.
   9  *
  10  * This code is derived from software contributed to The NetBSD Foundation
  11  * by Lennart Augustsson (lennart@augustsson.net) at
  12  * Carlstedt Research & Technology.
  13  *
  14  * Redistribution and use in source and binary forms, with or without
  15  * modification, are permitted provided that the following conditions
  16  * are met:
  17  * 1. Redistributions of source code must retain the above copyright
  18  *    notice, this list of conditions and the following disclaimer.
  19  * 2. Redistributions in binary form must reproduce the above copyright
  20  *    notice, this list of conditions and the following disclaimer in the
  21  *    documentation and/or other materials provided with the distribution.
  22  *
  23  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
  24  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  25  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  26  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
  27  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  28  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  29  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  30  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  31  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  32  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  33  * POSSIBILITY OF SUCH DAMAGE.
  34  */
  35
  36 #include <sys/stdint.h>
  37 #include <sys/stddef.h>
  38 #include <sys/param.h>
  39 #include <sys/queue.h>
  40 #include <sys/types.h>
  41 #include <sys/systm.h>
  42 #include <sys/kernel.h>
  43 #include <sys/bus.h>
  44 #include <sys/linker_set.h>
  45 #include <sys/module.h>
  46 #include <sys/lock.h>
  47 #include <sys/mutex.h>
  48 #include <sys/condvar.h>
  49 #include <sys/sysctl.h>
  50 #include <sys/sx.h>
  51 #include <sys/unistd.h>
  52 #include <sys/callout.h>
  53 #include <sys/malloc.h>
  54 #include <sys/priv.h>
  55
  56 #include <dev/usb/usb.h>
  57 #include <dev/usb/usbdi.h>
  58 #include <dev/usb/usbdi_util.h>
  59 #include <dev/usb/usbhid.h>
  60
  61 #define USB_DEBUG_VAR usb_debug
  62
  63 #include <dev/usb/usb_core.h>
  64 #include <dev/usb/usb_debug.h>
  65 #include <dev/usb/usb_process.h>
  66 #include <dev/usb/usb_device.h>
  67 #include <dev/usb/usb_request.h>
  68
  69 static void hid_clear_local(struct hid_item *);
  70 static uint8_t hid_get_byte(struct hid_data *s, const uint16_t wSize);
  71
  72 #define MAXUSAGE 64
  73 #define MAXPUSH 4
  74 #define MAXID 16
  75
  76 struct hid_pos_data {
  77         int32_t rid;
  78         uint32_t pos;
  79 };
  80
  81 struct hid_data {
  82         const uint8_t *start;
  83         const uint8_t *end;
  84         const uint8_t *p;
  85         struct hid_item cur[MAXPUSH];
  86         struct hid_pos_data last_pos[MAXID];
  87         int32_t usages_min[MAXUSAGE];
  88         int32_t usages_max[MAXUSAGE];
  89         int32_t usage_last;     /* last seen usage */
  90         uint32_t loc_size;      /* last seen size */
  91         uint32_t loc_count;     /* last seen count */
  92         uint8_t kindset;        /* we have 5 kinds so 8 bits are enough */
  93         uint8_t pushlevel;      /* current pushlevel */
  94         uint8_t ncount;         /* end usage item count */
  95         uint8_t icount;         /* current usage item count */
  96         uint8_t nusage;         /* end "usages_min/max" index */
  97         uint8_t iusage;         /* current "usages_min/max" index */
  98         uint8_t ousage;         /* current "usages_min/max" offset */
  99         uint8_t susage;         /* usage set flags */
 100 };
 101
 102 /*------------------------------------------------------------------------*
 103  *      hid_clear_local
 104  *------------------------------------------------------------------------*/
 105 static void
 106 hid_clear_local(struct hid_item *c)
 107 {
 108
 109         c->loc.count = 0;
 110         c->loc.size = 0;
 111         c->usage = 0;
 112         c->usage_minimum = 0;
 113         c->usage_maximum = 0;
 114         c->designator_index = 0;
 115         c->designator_minimum = 0;
 116         c->designator_maximum = 0;
 117         c->string_index = 0;
 118         c->string_minimum = 0;
 119         c->string_maximum = 0;
 120         c->set_delimiter = 0;
 121 }
 122
 123 static void
 124 hid_switch_rid(struct hid_data *s, struct hid_item *c, int32_t next_rID)
 125 {
 126         uint8_t i;
 127
 128         /* check for same report ID - optimise */
 129
 130         if (c->report_ID == next_rID)
 131                 return;
 132
 133         /* save current position for current rID */
 134
 135         if (c->report_ID == 0) {
 136                 i = 0;
 137         } else {
 138                 for (i = 1; i != MAXID; i++) {
 139                         if (s->last_pos[i].rid == c->report_ID)
 140                                 break;
 141                         if (s->last_pos[i].rid == 0)
 142                                 break;
 143                 }
 144         }
 145         if (i != MAXID) {
 146                 s->last_pos[i].rid = c->report_ID;
 147                 s->last_pos[i].pos = c->loc.pos;
 148         }
 149
 150         /* store next report ID */
 151
 152         c->report_ID = next_rID;
 153
 154         /* lookup last position for next rID */
 155
 156         if (next_rID == 0) {
 157                 i = 0;
 158         } else {
 159                 for (i = 1; i != MAXID; i++) {
 160                         if (s->last_pos[i].rid == next_rID)
 161                                 break;
 162                         if (s->last_pos[i].rid == 0)
 163                                 break;
 164                 }
 165         }
 166         if (i != MAXID) {
 167                 s->last_pos[i].rid = next_rID;
 168                 c->loc.pos = s->last_pos[i].pos;
 169         } else {
 170                 DPRINTF("Out of RID entries, position is set to zero!\n");
 171                 c->loc.pos = 0;
 172         }
 173 }
 174
 175 /*------------------------------------------------------------------------*
 176  *      hid_start_parse
 177  *------------------------------------------------------------------------*/
 178 struct hid_data *
 179 hid_start_parse(const void *d, usb_size_t len, int kindset)
 180 {
 181         struct hid_data *s;
 182
 183         if ((kindset-1) & kindset) {
 184                 DPRINTFN(0, "Only one bit can be "
 185                     "set in the kindset\n");
 186                 return (NULL);
 187         }
 188
 189         s = malloc(sizeof *s, M_TEMP, M_WAITOK | M_ZERO);
 190         s->start = s->p = d;
 191         s->end = ((const uint8_t *)d) + len;
 192         s->kindset = kindset;
 193         return (s);
 194 }
 195
 196 /*------------------------------------------------------------------------*
 197  *      hid_end_parse
 198  *------------------------------------------------------------------------*/
 199 void
 200 hid_end_parse(struct hid_data *s)
 201 {
 202         if (s == NULL)
 203                 return;
 204
 205         free(s, M_TEMP);
 206 }
 207
 208 /*------------------------------------------------------------------------*
 209  *      get byte from HID descriptor
 210  *------------------------------------------------------------------------*/
 211 static uint8_t
 212 hid_get_byte(struct hid_data *s, const uint16_t wSize)
 213 {
 214         const uint8_t *ptr;
 215         uint8_t retval;
 216
 217         ptr = s->p;
 218
 219         /* check if end is reached */
 220         if (ptr == s->end)
 221                 return (0);
 222
 223         /* read out a byte */
 224         retval = *ptr;
 225
 226         /* check if data pointer can be advanced by "wSize" bytes */
 227         if ((s->end - ptr) < wSize)
 228                 ptr = s->end;
 229         else
 230                 ptr += wSize;
 231
 232         /* update pointer */
 233         s->p = ptr;
 234
 235         return (retval);
 236 }
 237
 238 /*------------------------------------------------------------------------*
 239  *      hid_get_item
 240  *------------------------------------------------------------------------*/
 241 int
 242 hid_get_item(struct hid_data *s, struct hid_item *h)
 243 {
 244         struct hid_item *c;
 245         unsigned int bTag, bType, bSize;
 246         uint32_t oldpos;
 247         int32_t mask;
 248         int32_t dval;
 249
 250         if (s == NULL)
 251                 return (0);
 252
 253         c = &s->cur[s->pushlevel];
 254
 255  top:
 256         /* check if there is an array of items */
 257         if (s->icount < s->ncount) {
 258                 /* get current usage */
 259                 if (s->iusage < s->nusage) {
 260                         dval = s->usages_min[s->iusage] + s->ousage;
 261                         c->usage = dval;
 262                         s->usage_last = dval;
 263                         if (dval == s->usages_max[s->iusage]) {
 264                                 s->iusage ++;
 265                                 s->ousage = 0;
 266                         } else {
 267                                 s->ousage ++;
 268                         }
 269                 } else {
 270                         DPRINTFN(1, "Using last usage\n");
 271                         dval = s->usage_last;
 272                 }
 273                 s->icount ++;
 274                 /*
 275                  * Only copy HID item, increment position and return
 276                  * if correct kindset!
 277                  */
 278                 if (s->kindset & (1 << c->kind)) {
 279                         *h = *c;
 280                         DPRINTFN(1, "%u,%u,%u\n", h->loc.pos,
 281                             h->loc.size, h->loc.count);
 282                         c->loc.pos += c->loc.size * c->loc.count;
 283                         return (1);
 284                 }
 285         }
 286
 287         /* reset state variables */
 288         s->icount = 0;
 289         s->ncount = 0;
 290         s->iusage = 0;
 291         s->nusage = 0;
 292         s->susage = 0;
 293         s->ousage = 0;
 294         hid_clear_local(c);
 295
 296         /* get next item */
 297         while (s->p != s->end) {
 298
 299                 bSize = hid_get_byte(s, 1);
 300                 if (bSize == 0xfe) {
 301                         /* long item */
 302                         bSize = hid_get_byte(s, 1);
 303                         bSize |= hid_get_byte(s, 1) << 8;
 304                         bTag = hid_get_byte(s, 1);
 305                         bType = 0xff;   /* XXX what should it be */
 306                 } else {
 307                         /* short item */
 308                         bTag = bSize >> 4;
 309                         bType = (bSize >> 2) & 3;
 310                         bSize &= 3;
 311                         if (bSize == 3)
 312                                 bSize = 4;
 313                 }
 314                 switch (bSize) {
 315                 case 0:
 316                         dval = 0;
 317                         mask = 0;
 318                         break;
 319                 case 1:
 320                         dval = (int8_t)hid_get_byte(s, 1);
 321                         mask = 0xFF;
 322                         break;
 323                 case 2:
 324                         dval = hid_get_byte(s, 1);
 325                         dval |= hid_get_byte(s, 1) << 8;
 326                         dval = (int16_t)dval;
 327                         mask = 0xFFFF;
 328                         break;
 329                 case 4:
 330                         dval = hid_get_byte(s, 1);
 331                         dval |= hid_get_byte(s, 1) << 8;
 332                         dval |= hid_get_byte(s, 1) << 16;
 333                         dval |= hid_get_byte(s, 1) << 24;
 334                         mask = 0xFFFFFFFF;
 335                         break;
 336                 default:
 337                         dval = hid_get_byte(s, bSize);
 338                         DPRINTFN(0, "bad length %u (data=0x%02x)\n",
 339                             bSize, dval);
 340                         continue;
 341                 }
 342
 343                 switch (bType) {
 344                 case 0:         /* Main */
 345                         switch (bTag) {
 346                         case 8: /* Input */
 347                                 c->kind = hid_input;
 348                                 c->flags = dval;
 349                 ret:
 350                                 c->loc.count = s->loc_count;
 351                                 c->loc.size = s->loc_size;
 352
 353                                 if (c->flags & HIO_VARIABLE) {
 354                                         /* range check usage count */
 355                                         if (c->loc.count > 255) {
 356                                                 DPRINTFN(0, "Number of "
 357                                                     "items truncated to 255\n");
 358                                                 s->ncount = 255;
 359                                         } else
 360                                                 s->ncount = c->loc.count;
 361
 362                                         /*
 363                                          * The "top" loop will return
 364                                          * one and one item:
 365                                          */
 366                                         c->loc.count = 1;
 367                                 } else {
 368                                         s->ncount = 1;
 369                                 }
 370                                 goto top;
 371
 372                         case 9: /* Output */
 373                                 c->kind = hid_output;
 374                                 c->flags = dval;
 375                                 goto ret;
 376                         case 10:        /* Collection */
 377                                 c->kind = hid_collection;
 378                                 c->collection = dval;
 379                                 c->collevel++;
 380                                 c->usage = s->usage_last;
 381                                 *h = *c;
 382                                 return (1);
 383                         case 11:        /* Feature */
 384                                 c->kind = hid_feature;
 385                                 c->flags = dval;
 386                                 goto ret;
 387                         case 12:        /* End collection */
 388                                 c->kind = hid_endcollection;
 389                                 if (c->collevel == 0) {
 390                                         DPRINTFN(0, "invalid end collection\n");
 391                                         return (0);
 392                                 }
 393                                 c->collevel--;
 394                                 *h = *c;
 395                                 return (1);
 396                         default:
 397                                 DPRINTFN(0, "Main bTag=%d\n", bTag);
 398                                 break;
 399                         }
 400                         break;
 401                 case 1:         /* Global */
 402                         switch (bTag) {
 403                         case 0:
 404                                 c->_usage_page = dval << 16;
 405                                 break;
 406                         case 1:
 407                                 c->logical_minimum = dval;
 408                                 break;
 409                         case 2:
 410                                 c->logical_maximum = dval;
 411                                 break;
 412                         case 3:
 413                                 c->physical_minimum = dval;
 414                                 break;
 415                         case 4:
 416                                 c->physical_maximum = dval;
 417                                 break;
 418                         case 5:
 419                                 c->unit_exponent = dval;
 420                                 break;
 421                         case 6:
 422                                 c->unit = dval;
 423                                 break;
 424                         case 7:
 425                                 /* mask because value is unsigned */
 426                                 s->loc_size = dval & mask;
 427                                 break;
 428                         case 8:
 429                                 hid_switch_rid(s, c, dval);
 430                                 break;
 431                         case 9:
 432                                 /* mask because value is unsigned */
 433                                 s->loc_count = dval & mask;
 434                                 break;
 435                         case 10:        /* Push */
 436                                 s->pushlevel ++;
 437                                 if (s->pushlevel < MAXPUSH) {
 438                                         s->cur[s->pushlevel] = *c;
 439                                         /* store size and count */
 440                                         c->loc.size = s->loc_size;
 441                                         c->loc.count = s->loc_count;
 442                                         /* update current item pointer */
 443                                         c = &s->cur[s->pushlevel];
 444                                 } else {
 445                                         DPRINTFN(0, "Cannot push "
 446                                             "item @ %d\n", s->pushlevel);
 447                                 }
 448                                 break;
 449                         case 11:        /* Pop */
 450                                 s->pushlevel --;
 451                                 if (s->pushlevel < MAXPUSH) {
 452                                         /* preserve position */
 453                                         oldpos = c->loc.pos;
 454                                         c = &s->cur[s->pushlevel];
 455                                         /* restore size and count */
 456                                         s->loc_size = c->loc.size;
 457                                         s->loc_count = c->loc.count;
 458                                         /* set default item location */
 459                                         c->loc.pos = oldpos;
 460                                         c->loc.size = 0;
 461                                         c->loc.count = 0;
 462                                 } else {
 463                                         DPRINTFN(0, "Cannot pop "
 464                                             "item @ %d\n", s->pushlevel);
 465                                 }
 466                                 break;
 467                         default:
 468                                 DPRINTFN(0, "Global bTag=%d\n", bTag);
 469                                 break;
 470                         }
 471                         break;
 472                 case 2:         /* Local */
 473                         switch (bTag) {
 474                         case 0:
 475                                 if (bSize != 4)
 476                                         dval = (dval & mask) | c->_usage_page;
 477
 478                                 /* set last usage, in case of a collection */
 479                                 s->usage_last = dval;
 480
 481                                 if (s->nusage < MAXUSAGE) {
 482                                         s->usages_min[s->nusage] = dval;
 483                                         s->usages_max[s->nusage] = dval;
 484                                         s->nusage ++;
 485                                 } else {
 486                                         DPRINTFN(0, "max usage reached\n");
 487                                 }
 488
 489                                 /* clear any pending usage sets */
 490                                 s->susage = 0;
 491                                 break;
 492                         case 1:
 493                                 s->susage |= 1;
 494
 495                                 if (bSize != 4)
 496                                         dval = (dval & mask) | c->_usage_page;
 497                                 c->usage_minimum = dval;
 498
 499                                 goto check_set;
 500                         case 2:
 501                                 s->susage |= 2;
 502
 503                                 if (bSize != 4)
 504                                         dval = (dval & mask) | c->_usage_page;
 505                                 c->usage_maximum = dval;
 506
 507                         check_set:
 508                                 if (s->susage != 3)
 509                                         break;
 510
 511                                 /* sanity check */
 512                                 if ((s->nusage < MAXUSAGE) &&
 513                                     (c->usage_minimum <= c->usage_maximum)) {
 514                                         /* add usage range */
 515                                         s->usages_min[s->nusage] =
 516                                             c->usage_minimum;
 517                                         s->usages_max[s->nusage] =
 518                                             c->usage_maximum;
 519                                         s->nusage ++;
 520                                 } else {
 521                                         DPRINTFN(0, "Usage set dropped\n");
 522                                 }
 523                                 s->susage = 0;
 524                                 break;
 525                         case 3:
 526                                 c->designator_index = dval;
 527                                 break;
 528                         case 4:
 529                                 c->designator_minimum = dval;
 530                                 break;
 531                         case 5:
 532                                 c->designator_maximum = dval;
 533                                 break;
 534                         case 7:
 535                                 c->string_index = dval;
 536                                 break;
 537                         case 8:
 538                                 c->string_minimum = dval;
 539                                 break;
 540                         case 9:
 541                                 c->string_maximum = dval;
 542                                 break;
 543                         case 10:
 544                                 c->set_delimiter = dval;
 545                                 break;
 546                         default:
 547                                 DPRINTFN(0, "Local bTag=%d\n", bTag);
 548                                 break;
 549                         }
 550                         break;
 551                 default:
 552                         DPRINTFN(0, "default bType=%d\n", bType);
 553                         break;
 554                 }
 555         }
 556         return (0);
 557 }
 558
 559 /*------------------------------------------------------------------------*
 560  *      hid_report_size
 561  *------------------------------------------------------------------------*/
 562 int
 563 hid_report_size(const void *buf, usb_size_t len, enum hid_kind k, uint8_t *id)
 564 {
 565         struct hid_data *d;
 566         struct hid_item h;
 567         uint32_t temp;
 568         uint32_t hpos;
 569         uint32_t lpos;
 570         uint8_t any_id;
 571
 572         any_id = 0;
 573         hpos = 0;
 574         lpos = 0xFFFFFFFF;
 575
 576         for (d = hid_start_parse(buf, len, 1 << k); hid_get_item(d, &h);) {
 577                 if (h.kind == k) {
 578                         /* check for ID-byte presense */
 579                         if ((h.report_ID != 0) && !any_id) {
 580                                 if (id != NULL)
 581                                         *id = h.report_ID;
 582                                 any_id = 1;
 583                         }
 584                         /* compute minimum */
 585                         if (lpos > h.loc.pos)
 586                                 lpos = h.loc.pos;
 587                         /* compute end position */
 588                         temp = h.loc.pos + (h.loc.size * h.loc.count);
 589                         /* compute maximum */
 590                         if (hpos < temp)
 591                                 hpos = temp;
 592                 }
 593         }
 594         hid_end_parse(d);
 595
 596         /* safety check - can happen in case of currupt descriptors */
 597         if (lpos > hpos)
 598                 temp = 0;
 599         else
 600                 temp = hpos - lpos;
 601
 602         /* check for ID byte */
 603         if (any_id)
 604                 temp += 8;
 605         else if (id != NULL)
 606                 *id = 0;
 607
 608         /* return length in bytes rounded up */
 609         return ((temp + 7) / 8);
 610 }
 611
 612 /*------------------------------------------------------------------------*
 613  *      hid_locate
 614  *------------------------------------------------------------------------*/
 615 int
 616 hid_locate(const void *desc, usb_size_t size, uint32_t u, enum hid_kind k,
 617     uint8_t index, struct hid_location *loc, uint32_t *flags, uint8_t *id)
 618 {
 619         struct hid_data *d;
 620         struct hid_item h;
 621
 622         for (d = hid_start_parse(desc, size, 1 << k); hid_get_item(d, &h);) {
 623                 if (h.kind == k && !(h.flags & HIO_CONST) && h.usage == u) {
 624                         if (index--)
 625                                 continue;
 626                         if (loc != NULL)
 627                                 *loc = h.loc;
 628                         if (flags != NULL)
 629                                 *flags = h.flags;
 630                         if (id != NULL)
 631                                 *id = h.report_ID;
 632                         hid_end_parse(d);
 633                         return (1);
 634                 }
 635         }
 636         if (loc != NULL)
 637                 loc->size = 0;
 638         if (flags != NULL)
 639                 *flags = 0;
 640         if (id != NULL)
 641                 *id = 0;
 642         hid_end_parse(d);
 643         return (0);
 644 }
 645
 646 /*------------------------------------------------------------------------*
 647  *      hid_get_data
 648  *------------------------------------------------------------------------*/
 649 static uint32_t
 650 hid_get_data_sub(const uint8_t *buf, usb_size_t len, struct hid_location *loc,
 651     int is_signed)
 652 {
 653         uint32_t hpos = loc->pos;
 654         uint32_t hsize = loc->size;
 655         uint32_t data;
 656         uint32_t rpos;
 657         uint8_t n;
 658
 659         DPRINTFN(11, "hid_get_data: loc %d/%d\n", hpos, hsize);
 660
 661         /* Range check and limit */
 662         if (hsize == 0)
 663                 return (0);
 664         if (hsize > 32)
 665                 hsize = 32;
 666
 667         /* Get data in a safe way */
 668         data = 0;
 669         rpos = (hpos / 8);
 670         n = (hsize + 7) / 8;
 671         rpos += n;
 672         while (n--) {
 673                 rpos--;
 674                 if (rpos < len)
 675                         data |= buf[rpos] << (8 * n);
 676         }
 677
 678         /* Correctly shift down data */
 679         data = (data >> (hpos % 8));
 680         n = 32 - hsize;
 681
 682         /* Mask and sign extend in one */
 683         if (is_signed != 0)
 684                 data = (int32_t)((int32_t)data << n) >> n;
 685         else
 686                 data = (uint32_t)((uint32_t)data << n) >> n;
 687
 688         DPRINTFN(11, "hid_get_data: loc %d/%d = %lu\n",
 689             loc->pos, loc->size, (long)data);
 690         return (data);
 691 }
 692
 693 int32_t
 694 hid_get_data(const uint8_t *buf, usb_size_t len, struct hid_location *loc)
 695 {
 696         return (hid_get_data_sub(buf, len, loc, 1));
 697 }
 698
 699 uint32_t
 700 hid_get_data_unsigned(const uint8_t *buf, usb_size_t len, struct hid_location *loc)
 701 {
 702         return (hid_get_data_sub(buf, len, loc, 0));
 703 }
 704
 705 /*------------------------------------------------------------------------*
 706  *      hid_is_collection
 707  *------------------------------------------------------------------------*/
 708 int
 709 hid_is_collection(const void *desc, usb_size_t size, uint32_t usage)
 710 {
 711         struct hid_data *hd;
 712         struct hid_item hi;
 713         int err;
 714
 715         hd = hid_start_parse(desc, size, hid_input);
 716         if (hd == NULL)
 717                 return (0);
 718
 719         while ((err = hid_get_item(hd, &hi))) {
 720                  if (hi.kind == hid_collection &&
 721                      hi.usage == usage)
 722                         break;
 723         }
 724         hid_end_parse(hd);
 725         return (err);
 726 }
 727
 728 /*------------------------------------------------------------------------*
 729  *      hid_get_descriptor_from_usb
 730  *
 731  * This function will search for a HID descriptor between two USB
 732  * interface descriptors.
 733  *
 734  * Return values:
 735  * NULL: No more HID descriptors.
 736  * Else: Pointer to HID descriptor.
 737  *------------------------------------------------------------------------*/
 738 struct usb_hid_descriptor *
 739 hid_get_descriptor_from_usb(struct usb_config_descriptor *cd,
 740     struct usb_interface_descriptor *id)
 741 {
 742         struct usb_descriptor *desc = (void *)id;
 743
 744         if (desc == NULL) {
 745                 return (NULL);
 746         }
 747         while ((desc = usb_desc_foreach(cd, desc))) {
 748                 if ((desc->bDescriptorType == UDESC_HID) &&
 749                     (desc->bLength >= USB_HID_DESCRIPTOR_SIZE(0))) {
 750                         return (void *)desc;
 751                 }
 752                 if (desc->bDescriptorType == UDESC_INTERFACE) {
 753                         break;
 754                 }
 755         }
 756         return (NULL);
 757 }
 758
 759 /*------------------------------------------------------------------------*
 760  *      usbd_req_get_hid_desc
 761  *
 762  * This function will read out an USB report descriptor from the USB
 763  * device.
 764  *
 765  * Return values:
 766  * NULL: Failure.
 767  * Else: Success. The pointer should eventually be passed to free().
 768  *------------------------------------------------------------------------*/
 769 usb_error_t
 770 usbd_req_get_hid_desc(struct usb_device *udev, struct mtx *mtx,
 771     void **descp, uint16_t *sizep,
 772     struct malloc_type *mem, uint8_t iface_index)
 773 {
 774         struct usb_interface *iface = usbd_get_iface(udev, iface_index);
 775         struct usb_hid_descriptor *hid;
 776         usb_error_t err;
 777
 778         if ((iface == NULL) || (iface->idesc == NULL)) {
 779                 return (USB_ERR_INVAL);
 780         }
 781         hid = hid_get_descriptor_from_usb
 782             (usbd_get_config_descriptor(udev), iface->idesc);
 783
 784         if (hid == NULL) {
 785                 return (USB_ERR_IOERROR);
 786         }
 787         *sizep = UGETW(hid->descrs[0].wDescriptorLength);
 788         if (*sizep == 0) {
 789                 return (USB_ERR_IOERROR);
 790         }
 791         if (mtx)
 792                 mtx_unlock(mtx);
 793
 794         *descp = malloc(*sizep, mem, M_ZERO | M_WAITOK);
 795
 796         if (mtx)
 797                 mtx_lock(mtx);
 798
 799         if (*descp == NULL) {
 800                 return (USB_ERR_NOMEM);
 801         }
 802         err = usbd_req_get_report_descriptor
 803             (udev, mtx, *descp, *sizep, iface_index);
 804
 805         if (err) {
 806                 free(*descp, mem);
 807                 *descp = NULL;
 808                 return (err);
 809         }
 810         return (USB_ERR_NORMAL_COMPLETION);
 811 }