drivers/hid/hid-core.c

   1 /*
   2  *  HID support for Linux
   3  *
   4  *  Copyright (c) 1999 Andreas Gal
   5  *  Copyright (c) 2000-2005 Vojtech Pavlik <vojtech@suse.cz>
   6  *  Copyright (c) 2005 Michael Haboustak <mike-@cinci.rr.com> for Concept2, Inc
   7  *  Copyright (c) 2006-2007 Jiri Kosina
   8  */
   9
  10 /*
  11  * This program is free software; you can redistribute it and/or modify it
  12  * under the terms of the GNU General Public License as published by the Free
  13  * Software Foundation; either version 2 of the License, or (at your option)
  14  * any later version.
  15  */
  16
  17 #include <linux/module.h>
  18 #include <linux/slab.h>
  19 #include <linux/init.h>
  20 #include <linux/kernel.h>
  21 #include <linux/list.h>
  22 #include <linux/mm.h>
  23 #include <linux/spinlock.h>
  24 #include <asm/unaligned.h>
  25 #include <asm/byteorder.h>
  26 #include <linux/input.h>
  27 #include <linux/wait.h>
  28 #include <linux/vmalloc.h>
  29
  30 #include <linux/hid.h>
  31 #include <linux/hiddev.h>
  32 #include <linux/hid-debug.h>
  33
  34 /*
  35  * Version Information
  36  */
  37
  38 #define DRIVER_VERSION "v2.6"
  39 #define DRIVER_AUTHOR "Andreas Gal, Vojtech Pavlik, Jiri Kosina"
  40 #define DRIVER_DESC "HID core driver"
  41 #define DRIVER_LICENSE "GPL"
  42
  43 #ifdef CONFIG_HID_DEBUG
  44 int hid_debug = 0;
  45 module_param_named(debug, hid_debug, bool, 0600);
  46 MODULE_PARM_DESC(debug, "Turn HID debugging mode on and off");
  47 EXPORT_SYMBOL_GPL(hid_debug);
  48 #endif
  49
  50 /*
  51  * Register a new report for a device.
  52  */
  53
  54 static struct hid_report *hid_register_report(struct hid_device *device, unsigned type, unsigned id)
  55 {
  56         struct hid_report_enum *report_enum = device->report_enum + type;
  57         struct hid_report *report;
  58
  59         if (report_enum->report_id_hash[id])
  60                 return report_enum->report_id_hash[id];
  61
  62         if (!(report = kzalloc(sizeof(struct hid_report), GFP_KERNEL)))
  63                 return NULL;
  64
  65         if (id != 0)
  66                 report_enum->numbered = 1;
  67
  68         report->id = id;
  69         report->type = type;
  70         report->size = 0;
  71         report->device = device;
  72         report_enum->report_id_hash[id] = report;
  73
  74         list_add_tail(&report->list, &report_enum->report_list);
  75
  76         return report;
  77 }
  78
  79 /*
  80  * Register a new field for this report.
  81  */
  82
  83 static struct hid_field *hid_register_field(struct hid_report *report, unsigned usages, unsigned values)
  84 {
  85         struct hid_field *field;
  86
  87         if (report->maxfield == HID_MAX_FIELDS) {
  88                 dbg_hid("too many fields in report\n");
  89                 return NULL;
  90         }
  91
  92         if (!(field = kzalloc(sizeof(struct hid_field) + usages * sizeof(struct hid_usage)
  93                 + values * sizeof(unsigned), GFP_KERNEL))) return NULL;
  94
  95         field->index = report->maxfield++;
  96         report->field[field->index] = field;
  97         field->usage = (struct hid_usage *)(field + 1);
  98         field->value = (unsigned *)(field->usage + usages);
  99         field->report = report;
 100
 101         return field;
 102 }
 103
 104 /*
 105  * Open a collection. The type/usage is pushed on the stack.
 106  */
 107
 108 static int open_collection(struct hid_parser *parser, unsigned type)
 109 {
 110         struct hid_collection *collection;
 111         unsigned usage;
 112
 113         usage = parser->local.usage[0];
 114
 115         if (parser->collection_stack_ptr == HID_COLLECTION_STACK_SIZE) {
 116                 dbg_hid("collection stack overflow\n");
 117                 return -1;
 118         }
 119
 120         if (parser->device->maxcollection == parser->device->collection_size) {
 121                 collection = kmalloc(sizeof(struct hid_collection) *
 122                                 parser->device->collection_size * 2, GFP_KERNEL);
 123                 if (collection == NULL) {
 124                         dbg_hid("failed to reallocate collection array\n");
 125                         return -1;
 126                 }
 127                 memcpy(collection, parser->device->collection,
 128                         sizeof(struct hid_collection) *
 129                         parser->device->collection_size);
 130                 memset(collection + parser->device->collection_size, 0,
 131                         sizeof(struct hid_collection) *
 132                         parser->device->collection_size);
 133                 kfree(parser->device->collection);
 134                 parser->device->collection = collection;
 135                 parser->device->collection_size *= 2;
 136         }
 137
 138         parser->collection_stack[parser->collection_stack_ptr++] =
 139                 parser->device->maxcollection;
 140
 141         collection = parser->device->collection +
 142                 parser->device->maxcollection++;
 143         collection->type = type;
 144         collection->usage = usage;
 145         collection->level = parser->collection_stack_ptr - 1;
 146
 147         if (type == HID_COLLECTION_APPLICATION)
 148                 parser->device->maxapplication++;
 149
 150         return 0;
 151 }
 152
 153 /*
 154  * Close a collection.
 155  */
 156
 157 static int close_collection(struct hid_parser *parser)
 158 {
 159         if (!parser->collection_stack_ptr) {
 160                 dbg_hid("collection stack underflow\n");
 161                 return -1;
 162         }
 163         parser->collection_stack_ptr--;
 164         return 0;
 165 }
 166
 167 /*
 168  * Climb up the stack, search for the specified collection type
 169  * and return the usage.
 170  */
 171
 172 static unsigned hid_lookup_collection(struct hid_parser *parser, unsigned type)
 173 {
 174         int n;
 175         for (n = parser->collection_stack_ptr - 1; n >= 0; n--)
 176                 if (parser->device->collection[parser->collection_stack[n]].type == type)
 177                         return parser->device->collection[parser->collection_stack[n]].usage;
 178         return 0; /* we know nothing about this usage type */
 179 }
 180
 181 /*
 182  * Add a usage to the temporary parser table.
 183  */
 184
 185 static int hid_add_usage(struct hid_parser *parser, unsigned usage)
 186 {
 187         if (parser->local.usage_index >= HID_MAX_USAGES) {
 188                 dbg_hid("usage index exceeded\n");
 189                 return -1;
 190         }
 191         parser->local.usage[parser->local.usage_index] = usage;
 192         parser->local.collection_index[parser->local.usage_index] =
 193                 parser->collection_stack_ptr ?
 194                 parser->collection_stack[parser->collection_stack_ptr - 1] : 0;
 195         parser->local.usage_index++;
 196         return 0;
 197 }
 198
 199 /*
 200  * Register a new field for this report.
 201  */
 202
 203 static int hid_add_field(struct hid_parser *parser, unsigned report_type, unsigned flags)
 204 {
 205         struct hid_report *report;
 206         struct hid_field *field;
 207         int usages;
 208         unsigned offset;
 209         int i;
 210
 211         if (!(report = hid_register_report(parser->device, report_type, parser->global.report_id))) {
 212                 dbg_hid("hid_register_report failed\n");
 213                 return -1;
 214         }
 215
 216         if (parser->global.logical_maximum < parser->global.logical_minimum) {
 217                 dbg_hid("logical range invalid %d %d\n", parser->global.logical_minimum, parser->global.logical_maximum);
 218                 return -1;
 219         }
 220
 221         offset = report->size;
 222         report->size += parser->global.report_size * parser->global.report_count;
 223
 224         if (!parser->local.usage_index) /* Ignore padding fields */
 225                 return 0;
 226
 227         usages = max_t(int, parser->local.usage_index, parser->global.report_count);
 228
 229         if ((field = hid_register_field(report, usages, parser->global.report_count)) == NULL)
 230                 return 0;
 231
 232         field->physical = hid_lookup_collection(parser, HID_COLLECTION_PHYSICAL);
 233         field->logical = hid_lookup_collection(parser, HID_COLLECTION_LOGICAL);
 234         field->application = hid_lookup_collection(parser, HID_COLLECTION_APPLICATION);
 235
 236         for (i = 0; i < usages; i++) {
 237                 int j = i;
 238                 /* Duplicate the last usage we parsed if we have excess values */
 239                 if (i >= parser->local.usage_index)
 240                         j = parser->local.usage_index - 1;
 241                 field->usage[i].hid = parser->local.usage[j];
 242                 field->usage[i].collection_index =
 243                         parser->local.collection_index[j];
 244         }
 245
 246         field->maxusage = usages;
 247         field->flags = flags;
 248         field->report_offset = offset;
 249         field->report_type = report_type;
 250         field->report_size = parser->global.report_size;
 251         field->report_count = parser->global.report_count;
 252         field->logical_minimum = parser->global.logical_minimum;
 253         field->logical_maximum = parser->global.logical_maximum;
 254         field->physical_minimum = parser->global.physical_minimum;
 255         field->physical_maximum = parser->global.physical_maximum;
 256         field->unit_exponent = parser->global.unit_exponent;
 257         field->unit = parser->global.unit;
 258
 259         return 0;
 260 }
 261
 262 /*
 263  * Read data value from item.
 264  */
 265
 266 static u32 item_udata(struct hid_item *item)
 267 {
 268         switch (item->size) {
 269                 case 1: return item->data.u8;
 270                 case 2: return item->data.u16;
 271                 case 4: return item->data.u32;
 272         }
 273         return 0;
 274 }
 275
 276 static s32 item_sdata(struct hid_item *item)
 277 {
 278         switch (item->size) {
 279                 case 1: return item->data.s8;
 280                 case 2: return item->data.s16;
 281                 case 4: return item->data.s32;
 282         }
 283         return 0;
 284 }
 285
 286 /*
 287  * Process a global item.
 288  */
 289
 290 static int hid_parser_global(struct hid_parser *parser, struct hid_item *item)
 291 {
 292         switch (item->tag) {
 293
 294                 case HID_GLOBAL_ITEM_TAG_PUSH:
 295
 296                         if (parser->global_stack_ptr == HID_GLOBAL_STACK_SIZE) {
 297                                 dbg_hid("global enviroment stack overflow\n");
 298                                 return -1;
 299                         }
 300
 301                         memcpy(parser->global_stack + parser->global_stack_ptr++,
 302                                 &parser->global, sizeof(struct hid_global));
 303                         return 0;
 304
 305                 case HID_GLOBAL_ITEM_TAG_POP:
 306
 307                         if (!parser->global_stack_ptr) {
 308                                 dbg_hid("global enviroment stack underflow\n");
 309                                 return -1;
 310                         }
 311
 312                         memcpy(&parser->global, parser->global_stack + --parser->global_stack_ptr,
 313                                 sizeof(struct hid_global));
 314                         return 0;
 315
 316                 case HID_GLOBAL_ITEM_TAG_USAGE_PAGE:
 317                         parser->global.usage_page = item_udata(item);
 318                         return 0;
 319
 320                 case HID_GLOBAL_ITEM_TAG_LOGICAL_MINIMUM:
 321                         parser->global.logical_minimum = item_sdata(item);
 322                         return 0;
 323
 324                 case HID_GLOBAL_ITEM_TAG_LOGICAL_MAXIMUM:
 325                         if (parser->global.logical_minimum < 0)
 326                                 parser->global.logical_maximum = item_sdata(item);
 327                         else
 328                                 parser->global.logical_maximum = item_udata(item);
 329                         return 0;
 330
 331                 case HID_GLOBAL_ITEM_TAG_PHYSICAL_MINIMUM:
 332                         parser->global.physical_minimum = item_sdata(item);
 333                         return 0;
 334
 335                 case HID_GLOBAL_ITEM_TAG_PHYSICAL_MAXIMUM:
 336                         if (parser->global.physical_minimum < 0)
 337                                 parser->global.physical_maximum = item_sdata(item);
 338                         else
 339                                 parser->global.physical_maximum = item_udata(item);
 340                         return 0;
 341
 342                 case HID_GLOBAL_ITEM_TAG_UNIT_EXPONENT:
 343                         parser->global.unit_exponent = item_sdata(item);
 344                         return 0;
 345
 346                 case HID_GLOBAL_ITEM_TAG_UNIT:
 347                         parser->global.unit = item_udata(item);
 348                         return 0;
 349
 350                 case HID_GLOBAL_ITEM_TAG_REPORT_SIZE:
 351                         if ((parser->global.report_size = item_udata(item)) > 32) {
 352                                 dbg_hid("invalid report_size %d\n", parser->global.report_size);
 353                                 return -1;
 354                         }
 355                         return 0;
 356
 357                 case HID_GLOBAL_ITEM_TAG_REPORT_COUNT:
 358                         if ((parser->global.report_count = item_udata(item)) > HID_MAX_USAGES) {
 359                                 dbg_hid("invalid report_count %d\n", parser->global.report_count);
 360                                 return -1;
 361                         }
 362                         return 0;
 363
 364                 case HID_GLOBAL_ITEM_TAG_REPORT_ID:
 365                         if ((parser->global.report_id = item_udata(item)) == 0) {
 366                                 dbg_hid("report_id 0 is invalid\n");
 367                                 return -1;
 368                         }
 369                         return 0;
 370
 371                 default:
 372                         dbg_hid("unknown global tag 0x%x\n", item->tag);
 373                         return -1;
 374         }
 375 }
 376
 377 /*
 378  * Process a local item.
 379  */
 380
 381 static int hid_parser_local(struct hid_parser *parser, struct hid_item *item)
 382 {
 383         __u32 data;
 384         unsigned n;
 385
 386         if (item->size == 0) {
 387                 dbg_hid("item data expected for local item\n");
 388                 return -1;
 389         }
 390
 391         data = item_udata(item);
 392
 393         switch (item->tag) {
 394
 395                 case HID_LOCAL_ITEM_TAG_DELIMITER:
 396
 397                         if (data) {
 398                                 /*
 399                                  * We treat items before the first delimiter
 400                                  * as global to all usage sets (branch 0).
 401                                  * In the moment we process only these global
 402                                  * items and the first delimiter set.
 403                                  */
 404                                 if (parser->local.delimiter_depth != 0) {
 405                                         dbg_hid("nested delimiters\n");
 406                                         return -1;
 407                                 }
 408                                 parser->local.delimiter_depth++;
 409                                 parser->local.delimiter_branch++;
 410                         } else {
 411                                 if (parser->local.delimiter_depth < 1) {
 412                                         dbg_hid("bogus close delimiter\n");
 413                                         return -1;
 414                                 }
 415                                 parser->local.delimiter_depth--;
 416                         }
 417                         return 1;
 418
 419                 case HID_LOCAL_ITEM_TAG_USAGE:
 420
 421                         if (parser->local.delimiter_branch > 1) {
 422                                 dbg_hid("alternative usage ignored\n");
 423                                 return 0;
 424                         }
 425
 426                         if (item->size <= 2)
 427                                 data = (parser->global.usage_page << 16) + data;
 428
 429                         return hid_add_usage(parser, data);
 430
 431                 case HID_LOCAL_ITEM_TAG_USAGE_MINIMUM:
 432
 433                         if (parser->local.delimiter_branch > 1) {
 434                                 dbg_hid("alternative usage ignored\n");
 435                                 return 0;
 436                         }
 437
 438                         if (item->size <= 2)
 439                                 data = (parser->global.usage_page << 16) + data;
 440
 441                         parser->local.usage_minimum = data;
 442                         return 0;
 443
 444                 case HID_LOCAL_ITEM_TAG_USAGE_MAXIMUM:
 445
 446                         if (parser->local.delimiter_branch > 1) {
 447                                 dbg_hid("alternative usage ignored\n");
 448                                 return 0;
 449                         }
 450
 451                         if (item->size <= 2)
 452                                 data = (parser->global.usage_page << 16) + data;
 453
 454                         for (n = parser->local.usage_minimum; n <= data; n++)
 455                                 if (hid_add_usage(parser, n)) {
 456                                         dbg_hid("hid_add_usage failed\n");
 457                                         return -1;
 458                                 }
 459                         return 0;
 460
 461                 default:
 462
 463                         dbg_hid("unknown local item tag 0x%x\n", item->tag);
 464                         return 0;
 465         }
 466         return 0;
 467 }
 468
 469 /*
 470  * Process a main item.
 471  */
 472
 473 static int hid_parser_main(struct hid_parser *parser, struct hid_item *item)
 474 {
 475         __u32 data;
 476         int ret;
 477
 478         data = item_udata(item);
 479
 480         switch (item->tag) {
 481                 case HID_MAIN_ITEM_TAG_BEGIN_COLLECTION:
 482                         ret = open_collection(parser, data & 0xff);
 483                         break;
 484                 case HID_MAIN_ITEM_TAG_END_COLLECTION:
 485                         ret = close_collection(parser);
 486                         break;
 487                 case HID_MAIN_ITEM_TAG_INPUT:
 488                         ret = hid_add_field(parser, HID_INPUT_REPORT, data);
 489                         break;
 490                 case HID_MAIN_ITEM_TAG_OUTPUT:
 491                         ret = hid_add_field(parser, HID_OUTPUT_REPORT, data);
 492                         break;
 493                 case HID_MAIN_ITEM_TAG_FEATURE:
 494                         ret = hid_add_field(parser, HID_FEATURE_REPORT, data);
 495                         break;
 496                 default:
 497                         dbg_hid("unknown main item tag 0x%x\n", item->tag);
 498                         ret = 0;
 499         }
 500
 501         memset(&parser->local, 0, sizeof(parser->local));       /* Reset the local parser environment */
 502
 503         return ret;
 504 }
 505
 506 /*
 507  * Process a reserved item.
 508  */
 509
 510 static int hid_parser_reserved(struct hid_parser *parser, struct hid_item *item)
 511 {
 512         dbg_hid("reserved item type, tag 0x%x\n", item->tag);
 513         return 0;
 514 }
 515
 516 /*
 517  * Free a report and all registered fields. The field->usage and
 518  * field->value table's are allocated behind the field, so we need
 519  * only to free(field) itself.
 520  */
 521
 522 static void hid_free_report(struct hid_report *report)
 523 {
 524         unsigned n;
 525
 526         for (n = 0; n < report->maxfield; n++)
 527                 kfree(report->field[n]);
 528         kfree(report);
 529 }
 530
 531 /*
 532  * Free a device structure, all reports, and all fields.
 533  */
 534
 535 void hid_free_device(struct hid_device *device)
 536 {
 537         unsigned i,j;
 538
 539         for (i = 0; i < HID_REPORT_TYPES; i++) {
 540                 struct hid_report_enum *report_enum = device->report_enum + i;
 541
 542                 for (j = 0; j < 256; j++) {
 543                         struct hid_report *report = report_enum->report_id_hash[j];
 544                         if (report)
 545                                 hid_free_report(report);
 546                 }
 547         }
 548
 549         kfree(device->rdesc);
 550         kfree(device->collection);
 551         kfree(device);
 552 }
 553 EXPORT_SYMBOL_GPL(hid_free_device);
 554
 555 /*
 556  * Fetch a report description item from the data stream. We support long
 557  * items, though they are not used yet.
 558  */
 559
 560 static u8 *fetch_item(__u8 *start, __u8 *end, struct hid_item *item)
 561 {
 562         u8 b;
 563
 564         if ((end - start) <= 0)
 565                 return NULL;
 566
 567         b = *start++;
 568
 569         item->type = (b >> 2) & 3;
 570         item->tag  = (b >> 4) & 15;
 571
 572         if (item->tag == HID_ITEM_TAG_LONG) {
 573
 574                 item->format = HID_ITEM_FORMAT_LONG;
 575
 576                 if ((end - start) < 2)
 577                         return NULL;
 578
 579                 item->size = *start++;
 580                 item->tag  = *start++;
 581
 582                 if ((end - start) < item->size)
 583                         return NULL;
 584
 585                 item->data.longdata = start;
 586                 start += item->size;
 587                 return start;
 588         }
 589
 590         item->format = HID_ITEM_FORMAT_SHORT;
 591         item->size = b & 3;
 592
 593         switch (item->size) {
 594
 595                 case 0:
 596                         return start;
 597
 598                 case 1:
 599                         if ((end - start) < 1)
 600                                 return NULL;
 601                         item->data.u8 = *start++;
 602                         return start;
 603
 604                 case 2:
 605                         if ((end - start) < 2)
 606                                 return NULL;
 607                         item->data.u16 = le16_to_cpu(get_unaligned((__le16*)start));
 608                         start = (__u8 *)((__le16 *)start + 1);
 609                         return start;
 610
 611                 case 3:
 612                         item->size++;
 613                         if ((end - start) < 4)
 614                                 return NULL;
 615                         item->data.u32 = le32_to_cpu(get_unaligned((__le32*)start));
 616                         start = (__u8 *)((__le32 *)start + 1);
 617                         return start;
 618         }
 619
 620         return NULL;
 621 }
 622
 623 /*
 624  * Parse a report description into a hid_device structure. Reports are
 625  * enumerated, fields are attached to these reports.
 626  */
 627
 628 struct hid_device *hid_parse_report(__u8 *start, unsigned size)
 629 {
 630         struct hid_device *device;
 631         struct hid_parser *parser;
 632         struct hid_item item;
 633         __u8 *end;
 634         unsigned i;
 635         static int (*dispatch_type[])(struct hid_parser *parser,
 636                                       struct hid_item *item) = {
 637                 hid_parser_main,
 638                 hid_parser_global,
 639                 hid_parser_local,
 640                 hid_parser_reserved
 641         };
 642
 643         if (!(device = kzalloc(sizeof(struct hid_device), GFP_KERNEL)))
 644                 return NULL;
 645
 646         if (!(device->collection = kzalloc(sizeof(struct hid_collection) *
 647                                    HID_DEFAULT_NUM_COLLECTIONS, GFP_KERNEL))) {
 648                 kfree(device);
 649                 return NULL;
 650         }
 651         device->collection_size = HID_DEFAULT_NUM_COLLECTIONS;
 652
 653         for (i = 0; i < HID_REPORT_TYPES; i++)
 654                 INIT_LIST_HEAD(&device->report_enum[i].report_list);
 655
 656         if (!(device->rdesc = kmalloc(size, GFP_KERNEL))) {
 657                 kfree(device->collection);
 658                 kfree(device);
 659                 return NULL;
 660         }
 661         memcpy(device->rdesc, start, size);
 662         device->rsize = size;
 663
 664         if (!(parser = vmalloc(sizeof(struct hid_parser)))) {
 665                 kfree(device->rdesc);
 666                 kfree(device->collection);
 667                 kfree(device);
 668                 return NULL;
 669         }
 670         memset(parser, 0, sizeof(struct hid_parser));
 671         parser->device = device;
 672
 673         end = start + size;
 674         while ((start = fetch_item(start, end, &item)) != NULL) {
 675
 676                 if (item.format != HID_ITEM_FORMAT_SHORT) {
 677                         dbg_hid("unexpected long global item\n");
 678                         hid_free_device(device);
 679                         vfree(parser);
 680                         return NULL;
 681                 }
 682
 683                 if (dispatch_type[item.type](parser, &item)) {
 684                         dbg_hid("item %u %u %u %u parsing failed\n",
 685                                 item.format, (unsigned)item.size, (unsigned)item.type, (unsigned)item.tag);
 686                         hid_free_device(device);
 687                         vfree(parser);
 688                         return NULL;
 689                 }
 690
 691                 if (start == end) {
 692                         if (parser->collection_stack_ptr) {
 693                                 dbg_hid("unbalanced collection at end of report description\n");
 694                                 hid_free_device(device);
 695                                 vfree(parser);
 696                                 return NULL;
 697                         }
 698                         if (parser->local.delimiter_depth) {
 699                                 dbg_hid("unbalanced delimiter at end of report description\n");
 700                                 hid_free_device(device);
 701                                 vfree(parser);
 702                                 return NULL;
 703                         }
 704                         vfree(parser);
 705                         return device;
 706                 }
 707         }
 708
 709         dbg_hid("item fetching failed at offset %d\n", (int)(end - start));
 710         hid_free_device(device);
 711         vfree(parser);
 712         return NULL;
 713 }
 714 EXPORT_SYMBOL_GPL(hid_parse_report);
 715
 716 /*
 717  * Convert a signed n-bit integer to signed 32-bit integer. Common
 718  * cases are done through the compiler, the screwed things has to be
 719  * done by hand.
 720  */
 721
 722 static s32 snto32(__u32 value, unsigned n)
 723 {
 724         switch (n) {
 725                 case 8:  return ((__s8)value);
 726                 case 16: return ((__s16)value);
 727                 case 32: return ((__s32)value);
 728         }
 729         return value & (1 << (n - 1)) ? value | (-1 << n) : value;
 730 }
 731
 732 /*
 733  * Convert a signed 32-bit integer to a signed n-bit integer.
 734  */
 735
 736 static u32 s32ton(__s32 value, unsigned n)
 737 {
 738         s32 a = value >> (n - 1);
 739         if (a && a != -1)
 740                 return value < 0 ? 1 << (n - 1) : (1 << (n - 1)) - 1;
 741         return value & ((1 << n) - 1);
 742 }
 743
 744 /*
 745  * Extract/implement a data field from/to a little endian report (bit array).
 746  *
 747  * Code sort-of follows HID spec:
 748  *     http://www.usb.org/developers/devclass_docs/HID1_11.pdf
 749  *
 750  * While the USB HID spec allows unlimited length bit fields in "report
 751  * descriptors", most devices never use more than 16 bits.
 752  * One model of UPS is claimed to report "LINEV" as a 32-bit field.
 753  * Search linux-kernel and linux-usb-devel archives for "hid-core extract".
 754  */
 755
 756 static __inline__ __u32 extract(__u8 *report, unsigned offset, unsigned n)
 757 {
 758         u64 x;
 759
 760         WARN_ON(n > 32);
 761
 762         report += offset >> 3;  /* adjust byte index */
 763         offset &= 7;            /* now only need bit offset into one byte */
 764         x = le64_to_cpu(get_unaligned((__le64 *) report));
 765         x = (x >> offset) & ((1ULL << n) - 1);  /* extract bit field */
 766         return (u32) x;
 767 }
 768
 769 /*
 770  * "implement" : set bits in a little endian bit stream.
 771  * Same concepts as "extract" (see comments above).
 772  * The data mangled in the bit stream remains in little endian
 773  * order the whole time. It make more sense to talk about
 774  * endianness of register values by considering a register
 775  * a "cached" copy of the little endiad bit stream.
 776  */
 777 static __inline__ void implement(__u8 *report, unsigned offset, unsigned n, __u32 value)
 778 {
 779         __le64 x;
 780         u64 m = (1ULL << n) - 1;
 781
 782         WARN_ON(n > 32);
 783
 784         WARN_ON(value > m);
 785         value &= m;
 786
 787         report += offset >> 3;
 788         offset &= 7;
 789
 790         x = get_unaligned((__le64 *)report);
 791         x &= cpu_to_le64(~(m << offset));
 792         x |= cpu_to_le64(((u64) value) << offset);
 793         put_unaligned(x, (__le64 *) report);
 794 }
 795
 796 /*
 797  * Search an array for a value.
 798  */
 799
 800 static __inline__ int search(__s32 *array, __s32 value, unsigned n)
 801 {
 802         while (n--) {
 803                 if (*array++ == value)
 804                         return 0;
 805         }
 806         return -1;
 807 }
 808
 809 static void hid_process_event(struct hid_device *hid, struct hid_field *field, struct hid_usage *usage, __s32 value, int interrupt)
 810 {
 811         hid_dump_input(usage, value);
 812         if (hid->claimed & HID_CLAIMED_INPUT)
 813                 hidinput_hid_event(hid, field, usage, value);
 814         if (hid->claimed & HID_CLAIMED_HIDDEV && interrupt && hid->hiddev_hid_event)
 815                 hid->hiddev_hid_event(hid, field, usage, value);
 816 }
 817
 818 /*
 819  * Analyse a received field, and fetch the data from it. The field
 820  * content is stored for next report processing (we do differential
 821  * reporting to the layer).
 822  */
 823
 824 void hid_input_field(struct hid_device *hid, struct hid_field *field, __u8 *data, int interrupt)
 825 {
 826         unsigned n;
 827         unsigned count = field->report_count;
 828         unsigned offset = field->report_offset;
 829         unsigned size = field->report_size;
 830         __s32 min = field->logical_minimum;
 831         __s32 max = field->logical_maximum;
 832         __s32 *value;
 833
 834         if (!(value = kmalloc(sizeof(__s32) * count, GFP_ATOMIC)))
 835                 return;
 836
 837         for (n = 0; n < count; n++) {
 838
 839                         value[n] = min < 0 ? snto32(extract(data, offset + n * size, size), size) :
 840                                                     extract(data, offset + n * size, size);
 841
 842                         if (!(field->flags & HID_MAIN_ITEM_VARIABLE) /* Ignore report if ErrorRollOver */
 843                             && value[n] >= min && value[n] <= max
 844                             && field->usage[value[n] - min].hid == HID_UP_KEYBOARD + 1)
 845                                 goto exit;
 846         }
 847
 848         for (n = 0; n < count; n++) {
 849
 850                 if (HID_MAIN_ITEM_VARIABLE & field->flags) {
 851                         hid_process_event(hid, field, &field->usage[n], value[n], interrupt);
 852                         continue;
 853                 }
 854
 855                 if (field->value[n] >= min && field->value[n] <= max
 856                         && field->usage[field->value[n] - min].hid
 857                         && search(value, field->value[n], count))
 858                                 hid_process_event(hid, field, &field->usage[field->value[n] - min], 0, interrupt);
 859
 860                 if (value[n] >= min && value[n] <= max
 861                         && field->usage[value[n] - min].hid
 862                         && search(field->value, value[n], count))
 863                                 hid_process_event(hid, field, &field->usage[value[n] - min], 1, interrupt);
 864         }
 865
 866         memcpy(field->value, value, count * sizeof(__s32));
 867 exit:
 868         kfree(value);
 869 }
 870 EXPORT_SYMBOL_GPL(hid_input_field);
 871
 872 /*
 873  * Output the field into the report.
 874  */
 875
 876 static void hid_output_field(struct hid_field *field, __u8 *data)
 877 {
 878         unsigned count = field->report_count;
 879         unsigned offset = field->report_offset;
 880         unsigned size = field->report_size;
 881         unsigned bitsused = offset + count * size;
 882         unsigned n;
 883
 884         /* make sure the unused bits in the last byte are zeros */
 885         if (count > 0 && size > 0 && (bitsused % 8) != 0)
 886                 data[(bitsused-1)/8] &= (1 << (bitsused % 8)) - 1;
 887
 888         for (n = 0; n < count; n++) {
 889                 if (field->logical_minimum < 0) /* signed values */
 890                         implement(data, offset + n * size, size, s32ton(field->value[n], size));
 891                 else                            /* unsigned values */
 892                         implement(data, offset + n * size, size, field->value[n]);
 893         }
 894 }
 895
 896 /*
 897  * Create a report.
 898  */
 899
 900 void hid_output_report(struct hid_report *report, __u8 *data)
 901 {
 902         unsigned n;
 903
 904         if (report->id > 0)
 905                 *data++ = report->id;
 906
 907         for (n = 0; n < report->maxfield; n++)
 908                 hid_output_field(report->field[n], data);
 909 }
 910 EXPORT_SYMBOL_GPL(hid_output_report);
 911
 912 /*
 913  * Set a field value. The report this field belongs to has to be
 914  * created and transferred to the device, to set this value in the
 915  * device.
 916  */
 917
 918 int hid_set_field(struct hid_field *field, unsigned offset, __s32 value)
 919 {
 920         unsigned size = field->report_size;
 921
 922         hid_dump_input(field->usage + offset, value);
 923
 924         if (offset >= field->report_count) {
 925                 dbg_hid("offset (%d) exceeds report_count (%d)\n", offset, field->report_count);
 926                 hid_dump_field(field, 8);
 927                 return -1;
 928         }
 929         if (field->logical_minimum < 0) {
 930                 if (value != snto32(s32ton(value, size), size)) {
 931                         dbg_hid("value %d is out of range\n", value);
 932                         return -1;
 933                 }
 934         }
 935         field->value[offset] = value;
 936         return 0;
 937 }
 938 EXPORT_SYMBOL_GPL(hid_set_field);
 939
 940 int hid_input_report(struct hid_device *hid, int type, u8 *data, int size, int interrupt)
 941 {
 942         struct hid_report_enum *report_enum = hid->report_enum + type;
 943         struct hid_report *report;
 944         int n, rsize, i;
 945
 946         if (!hid)
 947                 return -ENODEV;
 948
 949         if (!size) {
 950                 dbg_hid("empty report\n");
 951                 return -1;
 952         }
 953
 954         dbg_hid("report (size %u) (%snumbered)\n", size, report_enum->numbered ? "" : "un");
 955
 956         n = 0;                          /* Normally report number is 0 */
 957         if (report_enum->numbered) {    /* Device uses numbered reports, data[0] is report number */
 958                 n = *data++;
 959                 size--;
 960         }
 961
 962         /* dump the report descriptor */
 963         dbg_hid("report %d (size %u) = ", n, size);
 964         for (i = 0; i < size; i++)
 965                 dbg_hid_line(" %02x", data[i]);
 966         dbg_hid_line("\n");
 967
 968         if (!(report = report_enum->report_id_hash[n])) {
 969                 dbg_hid("undefined report_id %d received\n", n);
 970                 return -1;
 971         }
 972
 973         rsize = ((report->size - 1) >> 3) + 1;
 974
 975         if (size < rsize) {
 976                 dbg_hid("report %d is too short, (%d < %d)\n", report->id, size, rsize);
 977                 memset(data + size, 0, rsize - size);
 978         }
 979
 980         if ((hid->claimed & HID_CLAIMED_HIDDEV) && hid->hiddev_report_event)
 981                 hid->hiddev_report_event(hid, report);
 982
 983         for (n = 0; n < report->maxfield; n++)
 984                 hid_input_field(hid, report->field[n], data, interrupt);
 985
 986         if (hid->claimed & HID_CLAIMED_INPUT)
 987                 hidinput_report_event(hid, report);
 988
 989         return 0;
 990 }
 991 EXPORT_SYMBOL_GPL(hid_input_report);
 992
 993 MODULE_LICENSE(DRIVER_LICENSE);
 994