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 #include <linux/sched.h>
  30
  31 #include <linux/hid.h>
  32 #include <linux/hiddev.h>
  33 #include <linux/hid-debug.h>
  34 #include <linux/hidraw.h>
  35
  36 /*
  37  * Version Information
  38  */
  39
  40 #define DRIVER_VERSION "v2.6"
  41 #define DRIVER_AUTHOR "Andreas Gal, Vojtech Pavlik, Jiri Kosina"
  42 #define DRIVER_DESC "HID core driver"
  43 #define DRIVER_LICENSE "GPL"
  44
  45 #ifdef CONFIG_HID_DEBUG
  46 int hid_debug = 0;
  47 module_param_named(debug, hid_debug, int, 0600);
  48 MODULE_PARM_DESC(debug, "HID debugging (0=off, 1=probing info, 2=continuous data dumping)");
  49 EXPORT_SYMBOL_GPL(hid_debug);
  50 #endif
  51
  52 /*
  53  * Register a new report for a device.
  54  */
  55
  56 static struct hid_report *hid_register_report(struct hid_device *device, unsigned type, unsigned id)
  57 {
  58         struct hid_report_enum *report_enum = device->report_enum + type;
  59         struct hid_report *report;
  60
  61         if (report_enum->report_id_hash[id])
  62                 return report_enum->report_id_hash[id];
  63
  64         if (!(report = kzalloc(sizeof(struct hid_report), GFP_KERNEL)))
  65                 return NULL;
  66
  67         if (id != 0)
  68                 report_enum->numbered = 1;
  69
  70         report->id = id;
  71         report->type = type;
  72         report->size = 0;
  73         report->device = device;
  74         report_enum->report_id_hash[id] = report;
  75
  76         list_add_tail(&report->list, &report_enum->report_list);
  77
  78         return report;
  79 }
  80
  81 /*
  82  * Register a new field for this report.
  83  */
  84
  85 static struct hid_field *hid_register_field(struct hid_report *report, unsigned usages, unsigned values)
  86 {
  87         struct hid_field *field;
  88
  89         if (report->maxfield == HID_MAX_FIELDS) {
  90                 dbg_hid("too many fields in report\n");
  91                 return NULL;
  92         }
  93
  94         if (!(field = kzalloc(sizeof(struct hid_field) + usages * sizeof(struct hid_usage)
  95                 + values * sizeof(unsigned), GFP_KERNEL))) return NULL;
  96
  97         field->index = report->maxfield++;
  98         report->field[field->index] = field;
  99         field->usage = (struct hid_usage *)(field + 1);
 100         field->value = (s32 *)(field->usage + usages);
 101         field->report = report;
 102
 103         return field;
 104 }
 105
 106 /*
 107  * Open a collection. The type/usage is pushed on the stack.
 108  */
 109
 110 static int open_collection(struct hid_parser *parser, unsigned type)
 111 {
 112         struct hid_collection *collection;
 113         unsigned usage;
 114
 115         usage = parser->local.usage[0];
 116
 117         if (parser->collection_stack_ptr == HID_COLLECTION_STACK_SIZE) {
 118                 dbg_hid("collection stack overflow\n");
 119                 return -1;
 120         }
 121
 122         if (parser->device->maxcollection == parser->device->collection_size) {
 123                 collection = kmalloc(sizeof(struct hid_collection) *
 124                                 parser->device->collection_size * 2, GFP_KERNEL);
 125                 if (collection == NULL) {
 126                         dbg_hid("failed to reallocate collection array\n");
 127                         return -1;
 128                 }
 129                 memcpy(collection, parser->device->collection,
 130                         sizeof(struct hid_collection) *
 131                         parser->device->collection_size);
 132                 memset(collection + parser->device->collection_size, 0,
 133                         sizeof(struct hid_collection) *
 134                         parser->device->collection_size);
 135                 kfree(parser->device->collection);
 136                 parser->device->collection = collection;
 137                 parser->device->collection_size *= 2;
 138         }
 139
 140         parser->collection_stack[parser->collection_stack_ptr++] =
 141                 parser->device->maxcollection;
 142
 143         collection = parser->device->collection +
 144                 parser->device->maxcollection++;
 145         collection->type = type;
 146         collection->usage = usage;
 147         collection->level = parser->collection_stack_ptr - 1;
 148
 149         if (type == HID_COLLECTION_APPLICATION)
 150                 parser->device->maxapplication++;
 151
 152         return 0;
 153 }
 154
 155 /*
 156  * Close a collection.
 157  */
 158
 159 static int close_collection(struct hid_parser *parser)
 160 {
 161         if (!parser->collection_stack_ptr) {
 162                 dbg_hid("collection stack underflow\n");
 163                 return -1;
 164         }
 165         parser->collection_stack_ptr--;
 166         return 0;
 167 }
 168
 169 /*
 170  * Climb up the stack, search for the specified collection type
 171  * and return the usage.
 172  */
 173
 174 static unsigned hid_lookup_collection(struct hid_parser *parser, unsigned type)
 175 {
 176         int n;
 177         for (n = parser->collection_stack_ptr - 1; n >= 0; n--)
 178                 if (parser->device->collection[parser->collection_stack[n]].type == type)
 179                         return parser->device->collection[parser->collection_stack[n]].usage;
 180         return 0; /* we know nothing about this usage type */
 181 }
 182
 183 /*
 184  * Add a usage to the temporary parser table.
 185  */
 186
 187 static int hid_add_usage(struct hid_parser *parser, unsigned usage)
 188 {
 189         if (parser->local.usage_index >= HID_MAX_USAGES) {
 190                 dbg_hid("usage index exceeded\n");
 191                 return -1;
 192         }
 193         parser->local.usage[parser->local.usage_index] = usage;
 194         parser->local.collection_index[parser->local.usage_index] =
 195                 parser->collection_stack_ptr ?
 196                 parser->collection_stack[parser->collection_stack_ptr - 1] : 0;
 197         parser->local.usage_index++;
 198         return 0;
 199 }
 200
 201 /*
 202  * Register a new field for this report.
 203  */
 204
 205 static int hid_add_field(struct hid_parser *parser, unsigned report_type, unsigned flags)
 206 {
 207         struct hid_report *report;
 208         struct hid_field *field;
 209         int usages;
 210         unsigned offset;
 211         int i;
 212
 213         if (!(report = hid_register_report(parser->device, report_type, parser->global.report_id))) {
 214                 dbg_hid("hid_register_report failed\n");
 215                 return -1;
 216         }
 217
 218         if (parser->global.logical_maximum < parser->global.logical_minimum) {
 219                 dbg_hid("logical range invalid %d %d\n", parser->global.logical_minimum, parser->global.logical_maximum);
 220                 return -1;
 221         }
 222
 223         offset = report->size;
 224         report->size += parser->global.report_size * parser->global.report_count;
 225
 226         if (!parser->local.usage_index) /* Ignore padding fields */
 227                 return 0;
 228
 229         usages = max_t(int, parser->local.usage_index, parser->global.report_count);
 230
 231         if ((field = hid_register_field(report, usages, parser->global.report_count)) == NULL)
 232                 return 0;
 233
 234         field->physical = hid_lookup_collection(parser, HID_COLLECTION_PHYSICAL);
 235         field->logical = hid_lookup_collection(parser, HID_COLLECTION_LOGICAL);
 236         field->application = hid_lookup_collection(parser, HID_COLLECTION_APPLICATION);
 237
 238         for (i = 0; i < usages; i++) {
 239                 int j = i;
 240                 /* Duplicate the last usage we parsed if we have excess values */
 241                 if (i >= parser->local.usage_index)
 242                         j = parser->local.usage_index - 1;
 243                 field->usage[i].hid = parser->local.usage[j];
 244                 field->usage[i].collection_index =
 245                         parser->local.collection_index[j];
 246         }
 247
 248         field->maxusage = usages;
 249         field->flags = flags;
 250         field->report_offset = offset;
 251         field->report_type = report_type;
 252         field->report_size = parser->global.report_size;
 253         field->report_count = parser->global.report_count;
 254         field->logical_minimum = parser->global.logical_minimum;
 255         field->logical_maximum = parser->global.logical_maximum;
 256         field->physical_minimum = parser->global.physical_minimum;
 257         field->physical_maximum = parser->global.physical_maximum;
 258         field->unit_exponent = parser->global.unit_exponent;
 259         field->unit = parser->global.unit;
 260
 261         return 0;
 262 }
 263
 264 /*
 265  * Read data value from item.
 266  */
 267
 268 static u32 item_udata(struct hid_item *item)
 269 {
 270         switch (item->size) {
 271                 case 1: return item->data.u8;
 272                 case 2: return item->data.u16;
 273                 case 4: return item->data.u32;
 274         }
 275         return 0;
 276 }
 277
 278 static s32 item_sdata(struct hid_item *item)
 279 {
 280         switch (item->size) {
 281                 case 1: return item->data.s8;
 282                 case 2: return item->data.s16;
 283                 case 4: return item->data.s32;
 284         }
 285         return 0;
 286 }
 287
 288 /*
 289  * Process a global item.
 290  */
 291
 292 static int hid_parser_global(struct hid_parser *parser, struct hid_item *item)
 293 {
 294         switch (item->tag) {
 295
 296                 case HID_GLOBAL_ITEM_TAG_PUSH:
 297
 298                         if (parser->global_stack_ptr == HID_GLOBAL_STACK_SIZE) {
 299                                 dbg_hid("global enviroment stack overflow\n");
 300                                 return -1;
 301                         }
 302
 303                         memcpy(parser->global_stack + parser->global_stack_ptr++,
 304                                 &parser->global, sizeof(struct hid_global));
 305                         return 0;
 306
 307                 case HID_GLOBAL_ITEM_TAG_POP:
 308
 309                         if (!parser->global_stack_ptr) {
 310                                 dbg_hid("global enviroment stack underflow\n");
 311                                 return -1;
 312                         }
 313
 314                         memcpy(&parser->global, parser->global_stack + --parser->global_stack_ptr,
 315                                 sizeof(struct hid_global));
 316                         return 0;
 317
 318                 case HID_GLOBAL_ITEM_TAG_USAGE_PAGE:
 319                         parser->global.usage_page = item_udata(item);
 320                         return 0;
 321
 322                 case HID_GLOBAL_ITEM_TAG_LOGICAL_MINIMUM:
 323                         parser->global.logical_minimum = item_sdata(item);
 324                         return 0;
 325
 326                 case HID_GLOBAL_ITEM_TAG_LOGICAL_MAXIMUM:
 327                         if (parser->global.logical_minimum < 0)
 328                                 parser->global.logical_maximum = item_sdata(item);
 329                         else
 330                                 parser->global.logical_maximum = item_udata(item);
 331                         return 0;
 332
 333                 case HID_GLOBAL_ITEM_TAG_PHYSICAL_MINIMUM:
 334                         parser->global.physical_minimum = item_sdata(item);
 335                         return 0;
 336
 337                 case HID_GLOBAL_ITEM_TAG_PHYSICAL_MAXIMUM:
 338                         if (parser->global.physical_minimum < 0)
 339                                 parser->global.physical_maximum = item_sdata(item);
 340                         else
 341                                 parser->global.physical_maximum = item_udata(item);
 342                         return 0;
 343
 344                 case HID_GLOBAL_ITEM_TAG_UNIT_EXPONENT:
 345                         parser->global.unit_exponent = item_sdata(item);
 346                         return 0;
 347
 348                 case HID_GLOBAL_ITEM_TAG_UNIT:
 349                         parser->global.unit = item_udata(item);
 350                         return 0;
 351
 352                 case HID_GLOBAL_ITEM_TAG_REPORT_SIZE:
 353                         if ((parser->global.report_size = item_udata(item)) > 32) {
 354                                 dbg_hid("invalid report_size %d\n", parser->global.report_size);
 355                                 return -1;
 356                         }
 357                         return 0;
 358
 359                 case HID_GLOBAL_ITEM_TAG_REPORT_COUNT:
 360                         if ((parser->global.report_count = item_udata(item)) > HID_MAX_USAGES) {
 361                                 dbg_hid("invalid report_count %d\n", parser->global.report_count);
 362                                 return -1;
 363                         }
 364                         return 0;
 365
 366                 case HID_GLOBAL_ITEM_TAG_REPORT_ID:
 367                         if ((parser->global.report_id = item_udata(item)) == 0) {
 368                                 dbg_hid("report_id 0 is invalid\n");
 369                                 return -1;
 370                         }
 371                         return 0;
 372
 373                 default:
 374                         dbg_hid("unknown global tag 0x%x\n", item->tag);
 375                         return -1;
 376         }
 377 }
 378
 379 /*
 380  * Process a local item.
 381  */
 382
 383 static int hid_parser_local(struct hid_parser *parser, struct hid_item *item)
 384 {
 385         __u32 data;
 386         unsigned n;
 387
 388         if (item->size == 0) {
 389                 dbg_hid("item data expected for local item\n");
 390                 return -1;
 391         }
 392
 393         data = item_udata(item);
 394
 395         switch (item->tag) {
 396
 397                 case HID_LOCAL_ITEM_TAG_DELIMITER:
 398
 399                         if (data) {
 400                                 /*
 401                                  * We treat items before the first delimiter
 402                                  * as global to all usage sets (branch 0).
 403                                  * In the moment we process only these global
 404                                  * items and the first delimiter set.
 405                                  */
 406                                 if (parser->local.delimiter_depth != 0) {
 407                                         dbg_hid("nested delimiters\n");
 408                                         return -1;
 409                                 }
 410                                 parser->local.delimiter_depth++;
 411                                 parser->local.delimiter_branch++;
 412                         } else {
 413                                 if (parser->local.delimiter_depth < 1) {
 414                                         dbg_hid("bogus close delimiter\n");
 415                                         return -1;
 416                                 }
 417                                 parser->local.delimiter_depth--;
 418                         }
 419                         return 1;
 420
 421                 case HID_LOCAL_ITEM_TAG_USAGE:
 422
 423                         if (parser->local.delimiter_branch > 1) {
 424                                 dbg_hid("alternative usage ignored\n");
 425                                 return 0;
 426                         }
 427
 428                         if (item->size <= 2)
 429                                 data = (parser->global.usage_page << 16) + data;
 430
 431                         return hid_add_usage(parser, data);
 432
 433                 case HID_LOCAL_ITEM_TAG_USAGE_MINIMUM:
 434
 435                         if (parser->local.delimiter_branch > 1) {
 436                                 dbg_hid("alternative usage ignored\n");
 437                                 return 0;
 438                         }
 439
 440                         if (item->size <= 2)
 441                                 data = (parser->global.usage_page << 16) + data;
 442
 443                         parser->local.usage_minimum = data;
 444                         return 0;
 445
 446                 case HID_LOCAL_ITEM_TAG_USAGE_MAXIMUM:
 447
 448                         if (parser->local.delimiter_branch > 1) {
 449                                 dbg_hid("alternative usage ignored\n");
 450                                 return 0;
 451                         }
 452
 453                         if (item->size <= 2)
 454                                 data = (parser->global.usage_page << 16) + data;
 455
 456                         for (n = parser->local.usage_minimum; n <= data; n++)
 457                                 if (hid_add_usage(parser, n)) {
 458                                         dbg_hid("hid_add_usage failed\n");
 459                                         return -1;
 460                                 }
 461                         return 0;
 462
 463                 default:
 464
 465                         dbg_hid("unknown local item tag 0x%x\n", item->tag);
 466                         return 0;
 467         }
 468         return 0;
 469 }
 470
 471 /*
 472  * Process a main item.
 473  */
 474
 475 static int hid_parser_main(struct hid_parser *parser, struct hid_item *item)
 476 {
 477         __u32 data;
 478         int ret;
 479
 480         data = item_udata(item);
 481
 482         switch (item->tag) {
 483                 case HID_MAIN_ITEM_TAG_BEGIN_COLLECTION:
 484                         ret = open_collection(parser, data & 0xff);
 485                         break;
 486                 case HID_MAIN_ITEM_TAG_END_COLLECTION:
 487                         ret = close_collection(parser);
 488                         break;
 489                 case HID_MAIN_ITEM_TAG_INPUT:
 490                         ret = hid_add_field(parser, HID_INPUT_REPORT, data);
 491                         break;
 492                 case HID_MAIN_ITEM_TAG_OUTPUT:
 493                         ret = hid_add_field(parser, HID_OUTPUT_REPORT, data);
 494                         break;
 495                 case HID_MAIN_ITEM_TAG_FEATURE:
 496                         ret = hid_add_field(parser, HID_FEATURE_REPORT, data);
 497                         break;
 498                 default:
 499                         dbg_hid("unknown main item tag 0x%x\n", item->tag);
 500                         ret = 0;
 501         }
 502
 503         memset(&parser->local, 0, sizeof(parser->local));       /* Reset the local parser environment */
 504
 505         return ret;
 506 }
 507
 508 /*
 509  * Process a reserved item.
 510  */
 511
 512 static int hid_parser_reserved(struct hid_parser *parser, struct hid_item *item)
 513 {
 514         dbg_hid("reserved item type, tag 0x%x\n", item->tag);
 515         return 0;
 516 }
 517
 518 /*
 519  * Free a report and all registered fields. The field->usage and
 520  * field->value table's are allocated behind the field, so we need
 521  * only to free(field) itself.
 522  */
 523
 524 static void hid_free_report(struct hid_report *report)
 525 {
 526         unsigned n;
 527
 528         for (n = 0; n < report->maxfield; n++)
 529                 kfree(report->field[n]);
 530         kfree(report);
 531 }
 532
 533 /*
 534  * Free a device structure, all reports, and all fields.
 535  */
 536
 537 void hid_free_device(struct hid_device *device)
 538 {
 539         unsigned i,j;
 540
 541         for (i = 0; i < HID_REPORT_TYPES; i++) {
 542                 struct hid_report_enum *report_enum = device->report_enum + i;
 543
 544                 for (j = 0; j < 256; j++) {
 545                         struct hid_report *report = report_enum->report_id_hash[j];
 546                         if (report)
 547                                 hid_free_report(report);
 548                 }
 549         }
 550
 551         kfree(device->rdesc);
 552         kfree(device->collection);
 553         kfree(device);
 554 }
 555 EXPORT_SYMBOL_GPL(hid_free_device);
 556
 557 /*
 558  * Fetch a report description item from the data stream. We support long
 559  * items, though they are not used yet.
 560  */
 561
 562 static u8 *fetch_item(__u8 *start, __u8 *end, struct hid_item *item)
 563 {
 564         u8 b;
 565
 566         if ((end - start) <= 0)
 567                 return NULL;
 568
 569         b = *start++;
 570
 571         item->type = (b >> 2) & 3;
 572         item->tag  = (b >> 4) & 15;
 573
 574         if (item->tag == HID_ITEM_TAG_LONG) {
 575
 576                 item->format = HID_ITEM_FORMAT_LONG;
 577
 578                 if ((end - start) < 2)
 579                         return NULL;
 580
 581                 item->size = *start++;
 582                 item->tag  = *start++;
 583
 584                 if ((end - start) < item->size)
 585                         return NULL;
 586
 587                 item->data.longdata = start;
 588                 start += item->size;
 589                 return start;
 590         }
 591
 592         item->format = HID_ITEM_FORMAT_SHORT;
 593         item->size = b & 3;
 594
 595         switch (item->size) {
 596
 597                 case 0:
 598                         return start;
 599
 600                 case 1:
 601                         if ((end - start) < 1)
 602                                 return NULL;
 603                         item->data.u8 = *start++;
 604                         return start;
 605
 606                 case 2:
 607                         if ((end - start) < 2)
 608                                 return NULL;
 609                         item->data.u16 = le16_to_cpu(get_unaligned((__le16*)start));
 610                         start = (__u8 *)((__le16 *)start + 1);
 611                         return start;
 612
 613                 case 3:
 614                         item->size++;
 615                         if ((end - start) < 4)
 616                                 return NULL;
 617                         item->data.u32 = le32_to_cpu(get_unaligned((__le32*)start));
 618                         start = (__u8 *)((__le32 *)start + 1);
 619                         return start;
 620         }
 621
 622         return NULL;
 623 }
 624
 625 /*
 626  * Parse a report description into a hid_device structure. Reports are
 627  * enumerated, fields are attached to these reports.
 628  */
 629
 630 struct hid_device *hid_parse_report(__u8 *start, unsigned size)
 631 {
 632         struct hid_device *device;
 633         struct hid_parser *parser;
 634         struct hid_item item;
 635         __u8 *end;
 636         unsigned i;
 637         static int (*dispatch_type[])(struct hid_parser *parser,
 638                                       struct hid_item *item) = {
 639                 hid_parser_main,
 640                 hid_parser_global,
 641                 hid_parser_local,
 642                 hid_parser_reserved
 643         };
 644
 645         if (!(device = kzalloc(sizeof(struct hid_device), GFP_KERNEL)))
 646                 return NULL;
 647
 648         if (!(device->collection = kzalloc(sizeof(struct hid_collection) *
 649                                    HID_DEFAULT_NUM_COLLECTIONS, GFP_KERNEL))) {
 650                 kfree(device);
 651                 return NULL;
 652         }
 653         device->collection_size = HID_DEFAULT_NUM_COLLECTIONS;
 654
 655         for (i = 0; i < HID_REPORT_TYPES; i++)
 656                 INIT_LIST_HEAD(&device->report_enum[i].report_list);
 657
 658         if (!(device->rdesc = kmalloc(size, GFP_KERNEL))) {
 659                 kfree(device->collection);
 660                 kfree(device);
 661                 return NULL;
 662         }
 663         memcpy(device->rdesc, start, size);
 664         device->rsize = size;
 665
 666         if (!(parser = vmalloc(sizeof(struct hid_parser)))) {
 667                 kfree(device->rdesc);
 668                 kfree(device->collection);
 669                 kfree(device);
 670                 return NULL;
 671         }
 672         memset(parser, 0, sizeof(struct hid_parser));
 673         parser->device = device;
 674
 675         end = start + size;
 676         while ((start = fetch_item(start, end, &item)) != NULL) {
 677
 678                 if (item.format != HID_ITEM_FORMAT_SHORT) {
 679                         dbg_hid("unexpected long global item\n");
 680                         hid_free_device(device);
 681                         vfree(parser);
 682                         return NULL;
 683                 }
 684
 685                 if (dispatch_type[item.type](parser, &item)) {
 686                         dbg_hid("item %u %u %u %u parsing failed\n",
 687                                 item.format, (unsigned)item.size, (unsigned)item.type, (unsigned)item.tag);
 688                         hid_free_device(device);
 689                         vfree(parser);
 690                         return NULL;
 691                 }
 692
 693                 if (start == end) {
 694                         if (parser->collection_stack_ptr) {
 695                                 dbg_hid("unbalanced collection at end of report description\n");
 696                                 hid_free_device(device);
 697                                 vfree(parser);
 698                                 return NULL;
 699                         }
 700                         if (parser->local.delimiter_depth) {
 701                                 dbg_hid("unbalanced delimiter at end of report description\n");
 702                                 hid_free_device(device);
 703                                 vfree(parser);
 704                                 return NULL;
 705                         }
 706                         vfree(parser);
 707                         return device;
 708                 }
 709         }
 710
 711         dbg_hid("item fetching failed at offset %d\n", (int)(end - start));
 712         hid_free_device(device);
 713         vfree(parser);
 714         return NULL;
 715 }
 716 EXPORT_SYMBOL_GPL(hid_parse_report);
 717
 718 /*
 719  * Convert a signed n-bit integer to signed 32-bit integer. Common
 720  * cases are done through the compiler, the screwed things has to be
 721  * done by hand.
 722  */
 723
 724 static s32 snto32(__u32 value, unsigned n)
 725 {
 726         switch (n) {
 727                 case 8:  return ((__s8)value);
 728                 case 16: return ((__s16)value);
 729                 case 32: return ((__s32)value);
 730         }
 731         return value & (1 << (n - 1)) ? value | (-1 << n) : value;
 732 }
 733
 734 /*
 735  * Convert a signed 32-bit integer to a signed n-bit integer.
 736  */
 737
 738 static u32 s32ton(__s32 value, unsigned n)
 739 {
 740         s32 a = value >> (n - 1);
 741         if (a && a != -1)
 742                 return value < 0 ? 1 << (n - 1) : (1 << (n - 1)) - 1;
 743         return value & ((1 << n) - 1);
 744 }
 745
 746 /*
 747  * Extract/implement a data field from/to a little endian report (bit array).
 748  *
 749  * Code sort-of follows HID spec:
 750  *     http://www.usb.org/developers/devclass_docs/HID1_11.pdf
 751  *
 752  * While the USB HID spec allows unlimited length bit fields in "report
 753  * descriptors", most devices never use more than 16 bits.
 754  * One model of UPS is claimed to report "LINEV" as a 32-bit field.
 755  * Search linux-kernel and linux-usb-devel archives for "hid-core extract".
 756  */
 757
 758 static __inline__ __u32 extract(__u8 *report, unsigned offset, unsigned n)
 759 {
 760         u64 x;
 761
 762         if (n > 32)
 763                 printk(KERN_WARNING "HID: extract() called with n (%d) > 32! (%s)\n",
 764                                 n, current->comm);
 765
 766         report += offset >> 3;  /* adjust byte index */
 767         offset &= 7;            /* now only need bit offset into one byte */
 768         x = le64_to_cpu(get_unaligned((__le64 *) report));
 769         x = (x >> offset) & ((1ULL << n) - 1);  /* extract bit field */
 770         return (u32) x;
 771 }
 772
 773 /*
 774  * "implement" : set bits in a little endian bit stream.
 775  * Same concepts as "extract" (see comments above).
 776  * The data mangled in the bit stream remains in little endian
 777  * order the whole time. It make more sense to talk about
 778  * endianness of register values by considering a register
 779  * a "cached" copy of the little endiad bit stream.
 780  */
 781 static __inline__ void implement(__u8 *report, unsigned offset, unsigned n, __u32 value)
 782 {
 783         __le64 x;
 784         u64 m = (1ULL << n) - 1;
 785
 786         if (n > 32)
 787                 printk(KERN_WARNING "HID: implement() called with n (%d) > 32! (%s)\n",
 788                                 n, current->comm);
 789
 790         if (value > m)
 791                 printk(KERN_WARNING "HID: implement() called with too large value %d! (%s)\n",
 792                                 value, current->comm);
 793         WARN_ON(value > m);
 794         value &= m;
 795
 796         report += offset >> 3;
 797         offset &= 7;
 798
 799         x = get_unaligned((__le64 *)report);
 800         x &= cpu_to_le64(~(m << offset));
 801         x |= cpu_to_le64(((u64) value) << offset);
 802         put_unaligned(x, (__le64 *) report);
 803 }
 804
 805 /*
 806  * Search an array for a value.
 807  */
 808
 809 static __inline__ int search(__s32 *array, __s32 value, unsigned n)
 810 {
 811         while (n--) {
 812                 if (*array++ == value)
 813                         return 0;
 814         }
 815         return -1;
 816 }
 817
 818 static void hid_process_event(struct hid_device *hid, struct hid_field *field, struct hid_usage *usage, __s32 value, int interrupt)
 819 {
 820         hid_dump_input(usage, value);
 821         if (hid->claimed & HID_CLAIMED_INPUT)
 822                 hidinput_hid_event(hid, field, usage, value);
 823         if (hid->claimed & HID_CLAIMED_HIDDEV && interrupt && hid->hiddev_hid_event)
 824                 hid->hiddev_hid_event(hid, field, usage, value);
 825 }
 826
 827 /*
 828  * Analyse a received field, and fetch the data from it. The field
 829  * content is stored for next report processing (we do differential
 830  * reporting to the layer).
 831  */
 832
 833 static void hid_input_field(struct hid_device *hid, struct hid_field *field,
 834                             __u8 *data, int interrupt)
 835 {
 836         unsigned n;
 837         unsigned count = field->report_count;
 838         unsigned offset = field->report_offset;
 839         unsigned size = field->report_size;
 840         __s32 min = field->logical_minimum;
 841         __s32 max = field->logical_maximum;
 842         __s32 *value;
 843
 844         if (!(value = kmalloc(sizeof(__s32) * count, GFP_ATOMIC)))
 845                 return;
 846
 847         for (n = 0; n < count; n++) {
 848
 849                         value[n] = min < 0 ? snto32(extract(data, offset + n * size, size), size) :
 850                                                     extract(data, offset + n * size, size);
 851
 852                         if (!(field->flags & HID_MAIN_ITEM_VARIABLE) /* Ignore report if ErrorRollOver */
 853                             && value[n] >= min && value[n] <= max
 854                             && field->usage[value[n] - min].hid == HID_UP_KEYBOARD + 1)
 855                                 goto exit;
 856         }
 857
 858         for (n = 0; n < count; n++) {
 859
 860                 if (HID_MAIN_ITEM_VARIABLE & field->flags) {
 861                         hid_process_event(hid, field, &field->usage[n], value[n], interrupt);
 862                         continue;
 863                 }
 864
 865                 if (field->value[n] >= min && field->value[n] <= max
 866                         && field->usage[field->value[n] - min].hid
 867                         && search(value, field->value[n], count))
 868                                 hid_process_event(hid, field, &field->usage[field->value[n] - min], 0, interrupt);
 869
 870                 if (value[n] >= min && value[n] <= max
 871                         && field->usage[value[n] - min].hid
 872                         && search(field->value, value[n], count))
 873                                 hid_process_event(hid, field, &field->usage[value[n] - min], 1, interrupt);
 874         }
 875
 876         memcpy(field->value, value, count * sizeof(__s32));
 877 exit:
 878         kfree(value);
 879 }
 880
 881 /*
 882  * Output the field into the report.
 883  */
 884
 885 static void hid_output_field(struct hid_field *field, __u8 *data)
 886 {
 887         unsigned count = field->report_count;
 888         unsigned offset = field->report_offset;
 889         unsigned size = field->report_size;
 890         unsigned bitsused = offset + count * size;
 891         unsigned n;
 892
 893         /* make sure the unused bits in the last byte are zeros */
 894         if (count > 0 && size > 0 && (bitsused % 8) != 0)
 895                 data[(bitsused-1)/8] &= (1 << (bitsused % 8)) - 1;
 896
 897         for (n = 0; n < count; n++) {
 898                 if (field->logical_minimum < 0) /* signed values */
 899                         implement(data, offset + n * size, size, s32ton(field->value[n], size));
 900                 else                            /* unsigned values */
 901                         implement(data, offset + n * size, size, field->value[n]);
 902         }
 903 }
 904
 905 /*
 906  * Create a report.
 907  */
 908
 909 void hid_output_report(struct hid_report *report, __u8 *data)
 910 {
 911         unsigned n;
 912
 913         if (report->id > 0)
 914                 *data++ = report->id;
 915
 916         for (n = 0; n < report->maxfield; n++)
 917                 hid_output_field(report->field[n], data);
 918 }
 919 EXPORT_SYMBOL_GPL(hid_output_report);
 920
 921 /*
 922  * Set a field value. The report this field belongs to has to be
 923  * created and transferred to the device, to set this value in the
 924  * device.
 925  */
 926
 927 int hid_set_field(struct hid_field *field, unsigned offset, __s32 value)
 928 {
 929         unsigned size = field->report_size;
 930
 931         hid_dump_input(field->usage + offset, value);
 932
 933         if (offset >= field->report_count) {
 934                 dbg_hid("offset (%d) exceeds report_count (%d)\n", offset, field->report_count);
 935                 hid_dump_field(field, 8);
 936                 return -1;
 937         }
 938         if (field->logical_minimum < 0) {
 939                 if (value != snto32(s32ton(value, size), size)) {
 940                         dbg_hid("value %d is out of range\n", value);
 941                         return -1;
 942                 }
 943         }
 944         field->value[offset] = value;
 945         return 0;
 946 }
 947 EXPORT_SYMBOL_GPL(hid_set_field);
 948
 949 int hid_input_report(struct hid_device *hid, int type, u8 *data, int size, int interrupt)
 950 {
 951         struct hid_report_enum *report_enum = hid->report_enum + type;
 952         struct hid_report *report;
 953         int n, rsize, i;
 954
 955         if (!hid)
 956                 return -ENODEV;
 957
 958         if (!size) {
 959                 dbg_hid("empty report\n");
 960                 return -1;
 961         }
 962
 963         dbg_hid("report (size %u) (%snumbered)\n", size, report_enum->numbered ? "" : "un");
 964
 965         n = 0;                          /* Normally report number is 0 */
 966         if (report_enum->numbered) {    /* Device uses numbered reports, data[0] is report number */
 967                 n = *data++;
 968                 size--;
 969         }
 970
 971         /* dump the report */
 972         dbg_hid("report %d (size %u) = ", n, size);
 973         for (i = 0; i < size; i++)
 974                 dbg_hid_line(" %02x", data[i]);
 975         dbg_hid_line("\n");
 976
 977         if (!(report = report_enum->report_id_hash[n])) {
 978                 dbg_hid("undefined report_id %d received\n", n);
 979                 return -1;
 980         }
 981
 982         rsize = ((report->size - 1) >> 3) + 1;
 983
 984         if (size < rsize) {
 985                 dbg_hid("report %d is too short, (%d < %d)\n", report->id, size, rsize);
 986                 memset(data + size, 0, rsize - size);
 987         }
 988
 989         if ((hid->claimed & HID_CLAIMED_HIDDEV) && hid->hiddev_report_event)
 990                 hid->hiddev_report_event(hid, report);
 991         if (hid->claimed & HID_CLAIMED_HIDRAW) {
 992                 /* numbered reports need to be passed with the report num */
 993                 if (report_enum->numbered)
 994                         hidraw_report_event(hid, data - 1, size + 1);
 995                 else
 996                         hidraw_report_event(hid, data, size);
 997         }
 998
 999         for (n = 0; n < report->maxfield; n++)
1000                 hid_input_field(hid, report->field[n], data, interrupt);
1001
1002         if (hid->claimed & HID_CLAIMED_INPUT)
1003                 hidinput_report_event(hid, report);
1004
1005         return 0;
1006 }
1007 EXPORT_SYMBOL_GPL(hid_input_report);
1008
1009 static int __init hid_init(void)
1010 {
1011         return hidraw_init();
1012 }
1013
1014 static void __exit hid_exit(void)
1015 {
1016         hidraw_exit();
1017 }
1018
1019 module_init(hid_init);
1020 module_exit(hid_exit);
1021
1022 MODULE_LICENSE(DRIVER_LICENSE);
1023