root/drivers/hid/hid-core.c

DEFINITIONS

1. hid_register_report
2. hid_register_field
3. open_collection
4. close_collection
5. hid_lookup_collection
6. complete_usage
7. hid_add_usage
8. hid_add_field
9. item_udata
10. item_sdata
11. hid_parser_global
12. hid_parser_local
13. hid_concatenate_last_usage_page
14. hid_parser_main
15. hid_parser_reserved
16. hid_free_report
17. hid_close_report
18. hid_device_release
19. fetch_item
20. hid_scan_input_usage
21. hid_scan_feature_usage
22. hid_scan_collection
23. hid_scan_main
24. hid_scan_report
25. hid_parse_report
26. hid_validate_values
27. hid_calculate_multiplier
28. hid_apply_multiplier_to_field
29. hid_apply_multiplier
30. hid_setup_resolution_multiplier
31. hid_open_report
32. snto32
33. hid_snto32
34. s32ton
35. __extract
36. hid_field_extract
37. __implement
38. implement
39. search
40. hid_match_report
41. hid_match_usage
42. hid_process_event
43. hid_input_field
44. hid_output_field
45. hid_output_report
46. hid_alloc_report_buf
47. hid_set_field
48. hid_get_report
49. __hid_request
50. hid_report_raw_event
51. hid_input_report
52. hid_match_one_id
53. hid_match_id
54. hid_hiddev
55. read_report_descriptor
56. show_country
57. hid_connect
58. hid_disconnect
59. hid_hw_start
60. hid_hw_stop
61. hid_hw_open
62. hid_hw_close
63. new_id_store
64. hid_free_dynids
65. hid_match_device
66. hid_bus_match
67. hid_compare_device_paths
68. hid_device_probe
69. hid_device_remove
70. modalias_show
71. hid_uevent
72. hid_add_device
73. hid_allocate_device
74. hid_remove_device
75. hid_destroy_device
76. __hid_bus_reprobe_drivers
77. __hid_bus_driver_added
78. __bus_removed_driver
79. __hid_register_driver
80. hid_unregister_driver
81. hid_check_keys_pressed
82. hid_init
83. hid_exit

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *  HID support for Linux
   4  *
   5  *  Copyright (c) 1999 Andreas Gal
   6  *  Copyright (c) 2000-2005 Vojtech Pavlik <vojtech@suse.cz>
   7  *  Copyright (c) 2005 Michael Haboustak <mike-@cinci.rr.com> for Concept2, Inc
   8  *  Copyright (c) 2006-2012 Jiri Kosina
   9  */
  10 
  11 /*
  12  */
  13 
  14 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  15 
  16 #include <linux/module.h>
  17 #include <linux/slab.h>
  18 #include <linux/init.h>
  19 #include <linux/kernel.h>
  20 #include <linux/list.h>
  21 #include <linux/mm.h>
  22 #include <linux/spinlock.h>
  23 #include <asm/unaligned.h>
  24 #include <asm/byteorder.h>
  25 #include <linux/input.h>
  26 #include <linux/wait.h>
  27 #include <linux/vmalloc.h>
  28 #include <linux/sched.h>
  29 #include <linux/semaphore.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 #include "hid-ids.h"
  37 
  38 /*
  39  * Version Information
  40  */
  41 
  42 #define DRIVER_DESC "HID core driver"
  43 
  44 int hid_debug = 0;
  45 module_param_named(debug, hid_debug, int, 0600);
  46 MODULE_PARM_DESC(debug, "toggle HID debugging messages");
  47 EXPORT_SYMBOL_GPL(hid_debug);
  48 
  49 static int hid_ignore_special_drivers = 0;
  50 module_param_named(ignore_special_drivers, hid_ignore_special_drivers, int, 0600);
  51 MODULE_PARM_DESC(ignore_special_drivers, "Ignore any special drivers and handle all devices by generic driver");
  52 
  53 /*
  54  * Register a new report for a device.
  55  */
  56 
  57 struct hid_report *hid_register_report(struct hid_device *device,
  58                                        unsigned int type, unsigned int id,
  59                                        unsigned int application)
  60 {
  61         struct hid_report_enum *report_enum = device->report_enum + type;
  62         struct hid_report *report;
  63 
  64         if (id >= HID_MAX_IDS)
  65                 return NULL;
  66         if (report_enum->report_id_hash[id])
  67                 return report_enum->report_id_hash[id];
  68 
  69         report = kzalloc(sizeof(struct hid_report), GFP_KERNEL);
  70         if (!report)
  71                 return NULL;
  72 
  73         if (id != 0)
  74                 report_enum->numbered = 1;
  75 
  76         report->id = id;
  77         report->type = type;
  78         report->size = 0;
  79         report->device = device;
  80         report->application = application;
  81         report_enum->report_id_hash[id] = report;
  82 
  83         list_add_tail(&report->list, &report_enum->report_list);
  84 
  85         return report;
  86 }
  87 EXPORT_SYMBOL_GPL(hid_register_report);
  88 
  89 /*
  90  * Register a new field for this report.
  91  */
  92 
  93 static struct hid_field *hid_register_field(struct hid_report *report, unsigned usages, unsigned values)
  94 {
  95         struct hid_field *field;
  96 
  97         if (report->maxfield == HID_MAX_FIELDS) {
  98                 hid_err(report->device, "too many fields in report\n");
  99                 return NULL;
 100         }
 101 
 102         field = kzalloc((sizeof(struct hid_field) +
 103                          usages * sizeof(struct hid_usage) +
 104                          values * sizeof(unsigned)), GFP_KERNEL);
 105         if (!field)
 106                 return NULL;
 107 
 108         field->index = report->maxfield++;
 109         report->field[field->index] = field;
 110         field->usage = (struct hid_usage *)(field + 1);
 111         field->value = (s32 *)(field->usage + usages);
 112         field->report = report;
 113 
 114         return field;
 115 }
 116 
 117 /*
 118  * Open a collection. The type/usage is pushed on the stack.
 119  */
 120 
 121 static int open_collection(struct hid_parser *parser, unsigned type)
 122 {
 123         struct hid_collection *collection;
 124         unsigned usage;
 125         int collection_index;
 126 
 127         usage = parser->local.usage[0];
 128 
 129         if (parser->collection_stack_ptr == parser->collection_stack_size) {
 130                 unsigned int *collection_stack;
 131                 unsigned int new_size = parser->collection_stack_size +
 132                                         HID_COLLECTION_STACK_SIZE;
 133 
 134                 collection_stack = krealloc(parser->collection_stack,
 135                                             new_size * sizeof(unsigned int),
 136                                             GFP_KERNEL);
 137                 if (!collection_stack)
 138                         return -ENOMEM;
 139 
 140                 parser->collection_stack = collection_stack;
 141                 parser->collection_stack_size = new_size;
 142         }
 143 
 144         if (parser->device->maxcollection == parser->device->collection_size) {
 145                 collection = kmalloc(
 146                                 array3_size(sizeof(struct hid_collection),
 147                                             parser->device->collection_size,
 148                                             2),
 149                                 GFP_KERNEL);
 150                 if (collection == NULL) {
 151                         hid_err(parser->device, "failed to reallocate collection array\n");
 152                         return -ENOMEM;
 153                 }
 154                 memcpy(collection, parser->device->collection,
 155                         sizeof(struct hid_collection) *
 156                         parser->device->collection_size);
 157                 memset(collection + parser->device->collection_size, 0,
 158                         sizeof(struct hid_collection) *
 159                         parser->device->collection_size);
 160                 kfree(parser->device->collection);
 161                 parser->device->collection = collection;
 162                 parser->device->collection_size *= 2;
 163         }
 164 
 165         parser->collection_stack[parser->collection_stack_ptr++] =
 166                 parser->device->maxcollection;
 167 
 168         collection_index = parser->device->maxcollection++;
 169         collection = parser->device->collection + collection_index;
 170         collection->type = type;
 171         collection->usage = usage;
 172         collection->level = parser->collection_stack_ptr - 1;
 173         collection->parent_idx = (collection->level == 0) ? -1 :
 174                 parser->collection_stack[collection->level - 1];
 175 
 176         if (type == HID_COLLECTION_APPLICATION)
 177                 parser->device->maxapplication++;
 178 
 179         return 0;
 180 }
 181 
 182 /*
 183  * Close a collection.
 184  */
 185 
 186 static int close_collection(struct hid_parser *parser)
 187 {
 188         if (!parser->collection_stack_ptr) {
 189                 hid_err(parser->device, "collection stack underflow\n");
 190                 return -EINVAL;
 191         }
 192         parser->collection_stack_ptr--;
 193         return 0;
 194 }
 195 
 196 /*
 197  * Climb up the stack, search for the specified collection type
 198  * and return the usage.
 199  */
 200 
 201 static unsigned hid_lookup_collection(struct hid_parser *parser, unsigned type)
 202 {
 203         struct hid_collection *collection = parser->device->collection;
 204         int n;
 205 
 206         for (n = parser->collection_stack_ptr - 1; n >= 0; n--) {
 207                 unsigned index = parser->collection_stack[n];
 208                 if (collection[index].type == type)
 209                         return collection[index].usage;
 210         }
 211         return 0; /* we know nothing about this usage type */
 212 }
 213 
 214 /*
 215  * Concatenate usage which defines 16 bits or less with the
 216  * currently defined usage page to form a 32 bit usage
 217  */
 218 
 219 static void complete_usage(struct hid_parser *parser, unsigned int index)
 220 {
 221         parser->local.usage[index] &= 0xFFFF;
 222         parser->local.usage[index] |=
 223                 (parser->global.usage_page & 0xFFFF) << 16;
 224 }
 225 
 226 /*
 227  * Add a usage to the temporary parser table.
 228  */
 229 
 230 static int hid_add_usage(struct hid_parser *parser, unsigned usage, u8 size)
 231 {
 232         if (parser->local.usage_index >= HID_MAX_USAGES) {
 233                 hid_err(parser->device, "usage index exceeded\n");
 234                 return -1;
 235         }
 236         parser->local.usage[parser->local.usage_index] = usage;
 237 
 238         /*
 239          * If Usage item only includes usage id, concatenate it with
 240          * currently defined usage page
 241          */
 242         if (size <= 2)
 243                 complete_usage(parser, parser->local.usage_index);
 244 
 245         parser->local.usage_size[parser->local.usage_index] = size;
 246         parser->local.collection_index[parser->local.usage_index] =
 247                 parser->collection_stack_ptr ?
 248                 parser->collection_stack[parser->collection_stack_ptr - 1] : 0;
 249         parser->local.usage_index++;
 250         return 0;
 251 }
 252 
 253 /*
 254  * Register a new field for this report.
 255  */
 256 
 257 static int hid_add_field(struct hid_parser *parser, unsigned report_type, unsigned flags)
 258 {
 259         struct hid_report *report;
 260         struct hid_field *field;
 261         unsigned int usages;
 262         unsigned int offset;
 263         unsigned int i;
 264         unsigned int application;
 265 
 266         application = hid_lookup_collection(parser, HID_COLLECTION_APPLICATION);
 267 
 268         report = hid_register_report(parser->device, report_type,
 269                                      parser->global.report_id, application);
 270         if (!report) {
 271                 hid_err(parser->device, "hid_register_report failed\n");
 272                 return -1;
 273         }
 274 
 275         /* Handle both signed and unsigned cases properly */
 276         if ((parser->global.logical_minimum < 0 &&
 277                 parser->global.logical_maximum <
 278                 parser->global.logical_minimum) ||
 279                 (parser->global.logical_minimum >= 0 &&
 280                 (__u32)parser->global.logical_maximum <
 281                 (__u32)parser->global.logical_minimum)) {
 282                 dbg_hid("logical range invalid 0x%x 0x%x\n",
 283                         parser->global.logical_minimum,
 284                         parser->global.logical_maximum);
 285                 return -1;
 286         }
 287 
 288         offset = report->size;
 289         report->size += parser->global.report_size * parser->global.report_count;
 290 
 291         /* Total size check: Allow for possible report index byte */
 292         if (report->size > (HID_MAX_BUFFER_SIZE - 1) << 3) {
 293                 hid_err(parser->device, "report is too long\n");
 294                 return -1;
 295         }
 296 
 297         if (!parser->local.usage_index) /* Ignore padding fields */
 298                 return 0;
 299 
 300         usages = max_t(unsigned, parser->local.usage_index,
 301                                  parser->global.report_count);
 302 
 303         field = hid_register_field(report, usages, parser->global.report_count);
 304         if (!field)
 305                 return 0;
 306 
 307         field->physical = hid_lookup_collection(parser, HID_COLLECTION_PHYSICAL);
 308         field->logical = hid_lookup_collection(parser, HID_COLLECTION_LOGICAL);
 309         field->application = application;
 310 
 311         for (i = 0; i < usages; i++) {
 312                 unsigned j = i;
 313                 /* Duplicate the last usage we parsed if we have excess values */
 314                 if (i >= parser->local.usage_index)
 315                         j = parser->local.usage_index - 1;
 316                 field->usage[i].hid = parser->local.usage[j];
 317                 field->usage[i].collection_index =
 318                         parser->local.collection_index[j];
 319                 field->usage[i].usage_index = i;
 320                 field->usage[i].resolution_multiplier = 1;
 321         }
 322 
 323         field->maxusage = usages;
 324         field->flags = flags;
 325         field->report_offset = offset;
 326         field->report_type = report_type;
 327         field->report_size = parser->global.report_size;
 328         field->report_count = parser->global.report_count;
 329         field->logical_minimum = parser->global.logical_minimum;
 330         field->logical_maximum = parser->global.logical_maximum;
 331         field->physical_minimum = parser->global.physical_minimum;
 332         field->physical_maximum = parser->global.physical_maximum;
 333         field->unit_exponent = parser->global.unit_exponent;
 334         field->unit = parser->global.unit;
 335 
 336         return 0;
 337 }
 338 
 339 /*
 340  * Read data value from item.
 341  */
 342 
 343 static u32 item_udata(struct hid_item *item)
 344 {
 345         switch (item->size) {
 346         case 1: return item->data.u8;
 347         case 2: return item->data.u16;
 348         case 4: return item->data.u32;
 349         }
 350         return 0;
 351 }
 352 
 353 static s32 item_sdata(struct hid_item *item)
 354 {
 355         switch (item->size) {
 356         case 1: return item->data.s8;
 357         case 2: return item->data.s16;
 358         case 4: return item->data.s32;
 359         }
 360         return 0;
 361 }
 362 
 363 /*
 364  * Process a global item.
 365  */
 366 
 367 static int hid_parser_global(struct hid_parser *parser, struct hid_item *item)
 368 {
 369         __s32 raw_value;
 370         switch (item->tag) {
 371         case HID_GLOBAL_ITEM_TAG_PUSH:
 372 
 373                 if (parser->global_stack_ptr == HID_GLOBAL_STACK_SIZE) {
 374                         hid_err(parser->device, "global environment stack overflow\n");
 375                         return -1;
 376                 }
 377 
 378                 memcpy(parser->global_stack + parser->global_stack_ptr++,
 379                         &parser->global, sizeof(struct hid_global));
 380                 return 0;
 381 
 382         case HID_GLOBAL_ITEM_TAG_POP:
 383 
 384                 if (!parser->global_stack_ptr) {
 385                         hid_err(parser->device, "global environment stack underflow\n");
 386                         return -1;
 387                 }
 388 
 389                 memcpy(&parser->global, parser->global_stack +
 390                         --parser->global_stack_ptr, sizeof(struct hid_global));
 391                 return 0;
 392 
 393         case HID_GLOBAL_ITEM_TAG_USAGE_PAGE:
 394                 parser->global.usage_page = item_udata(item);
 395                 return 0;
 396 
 397         case HID_GLOBAL_ITEM_TAG_LOGICAL_MINIMUM:
 398                 parser->global.logical_minimum = item_sdata(item);
 399                 return 0;
 400 
 401         case HID_GLOBAL_ITEM_TAG_LOGICAL_MAXIMUM:
 402                 if (parser->global.logical_minimum < 0)
 403                         parser->global.logical_maximum = item_sdata(item);
 404                 else
 405                         parser->global.logical_maximum = item_udata(item);
 406                 return 0;
 407 
 408         case HID_GLOBAL_ITEM_TAG_PHYSICAL_MINIMUM:
 409                 parser->global.physical_minimum = item_sdata(item);
 410                 return 0;
 411 
 412         case HID_GLOBAL_ITEM_TAG_PHYSICAL_MAXIMUM:
 413                 if (parser->global.physical_minimum < 0)
 414                         parser->global.physical_maximum = item_sdata(item);
 415                 else
 416                         parser->global.physical_maximum = item_udata(item);
 417                 return 0;
 418 
 419         case HID_GLOBAL_ITEM_TAG_UNIT_EXPONENT:
 420                 /* Many devices provide unit exponent as a two's complement
 421                  * nibble due to the common misunderstanding of HID
 422                  * specification 1.11, 6.2.2.7 Global Items. Attempt to handle
 423                  * both this and the standard encoding. */
 424                 raw_value = item_sdata(item);
 425                 if (!(raw_value & 0xfffffff0))
 426                         parser->global.unit_exponent = hid_snto32(raw_value, 4);
 427                 else
 428                         parser->global.unit_exponent = raw_value;
 429                 return 0;
 430 
 431         case HID_GLOBAL_ITEM_TAG_UNIT:
 432                 parser->global.unit = item_udata(item);
 433                 return 0;
 434 
 435         case HID_GLOBAL_ITEM_TAG_REPORT_SIZE:
 436                 parser->global.report_size = item_udata(item);
 437                 if (parser->global.report_size > 256) {
 438                         hid_err(parser->device, "invalid report_size %d\n",
 439                                         parser->global.report_size);
 440                         return -1;
 441                 }
 442                 return 0;
 443 
 444         case HID_GLOBAL_ITEM_TAG_REPORT_COUNT:
 445                 parser->global.report_count = item_udata(item);
 446                 if (parser->global.report_count > HID_MAX_USAGES) {
 447                         hid_err(parser->device, "invalid report_count %d\n",
 448                                         parser->global.report_count);
 449                         return -1;
 450                 }
 451                 return 0;
 452 
 453         case HID_GLOBAL_ITEM_TAG_REPORT_ID:
 454                 parser->global.report_id = item_udata(item);
 455                 if (parser->global.report_id == 0 ||
 456                     parser->global.report_id >= HID_MAX_IDS) {
 457                         hid_err(parser->device, "report_id %u is invalid\n",
 458                                 parser->global.report_id);
 459                         return -1;
 460                 }
 461                 return 0;
 462 
 463         default:
 464                 hid_err(parser->device, "unknown global tag 0x%x\n", item->tag);
 465                 return -1;
 466         }
 467 }
 468 
 469 /*
 470  * Process a local item.
 471  */
 472 
 473 static int hid_parser_local(struct hid_parser *parser, struct hid_item *item)
 474 {
 475         __u32 data;
 476         unsigned n;
 477         __u32 count;
 478 
 479         data = item_udata(item);
 480 
 481         switch (item->tag) {
 482         case HID_LOCAL_ITEM_TAG_DELIMITER:
 483 
 484                 if (data) {
 485                         /*
 486                          * We treat items before the first delimiter
 487                          * as global to all usage sets (branch 0).
 488                          * In the moment we process only these global
 489                          * items and the first delimiter set.
 490                          */
 491                         if (parser->local.delimiter_depth != 0) {
 492                                 hid_err(parser->device, "nested delimiters\n");
 493                                 return -1;
 494                         }
 495                         parser->local.delimiter_depth++;
 496                         parser->local.delimiter_branch++;
 497                 } else {
 498                         if (parser->local.delimiter_depth < 1) {
 499                                 hid_err(parser->device, "bogus close delimiter\n");
 500                                 return -1;
 501                         }
 502                         parser->local.delimiter_depth--;
 503                 }
 504                 return 0;
 505 
 506         case HID_LOCAL_ITEM_TAG_USAGE:
 507 
 508                 if (parser->local.delimiter_branch > 1) {
 509                         dbg_hid("alternative usage ignored\n");
 510                         return 0;
 511                 }
 512 
 513                 return hid_add_usage(parser, data, item->size);
 514 
 515         case HID_LOCAL_ITEM_TAG_USAGE_MINIMUM:
 516 
 517                 if (parser->local.delimiter_branch > 1) {
 518                         dbg_hid("alternative usage ignored\n");
 519                         return 0;
 520                 }
 521 
 522                 parser->local.usage_minimum = data;
 523                 return 0;
 524 
 525         case HID_LOCAL_ITEM_TAG_USAGE_MAXIMUM:
 526 
 527                 if (parser->local.delimiter_branch > 1) {
 528                         dbg_hid("alternative usage ignored\n");
 529                         return 0;
 530                 }
 531 
 532                 count = data - parser->local.usage_minimum;
 533                 if (count + parser->local.usage_index >= HID_MAX_USAGES) {
 534                         /*
 535                          * We do not warn if the name is not set, we are
 536                          * actually pre-scanning the device.
 537                          */
 538                         if (dev_name(&parser->device->dev))
 539                                 hid_warn(parser->device,
 540                                          "ignoring exceeding usage max\n");
 541                         data = HID_MAX_USAGES - parser->local.usage_index +
 542                                 parser->local.usage_minimum - 1;
 543                         if (data <= 0) {
 544                                 hid_err(parser->device,
 545                                         "no more usage index available\n");
 546                                 return -1;
 547                         }
 548                 }
 549 
 550                 for (n = parser->local.usage_minimum; n <= data; n++)
 551                         if (hid_add_usage(parser, n, item->size)) {
 552                                 dbg_hid("hid_add_usage failed\n");
 553                                 return -1;
 554                         }
 555                 return 0;
 556 
 557         default:
 558 
 559                 dbg_hid("unknown local item tag 0x%x\n", item->tag);
 560                 return 0;
 561         }
 562         return 0;
 563 }
 564 
 565 /*
 566  * Concatenate Usage Pages into Usages where relevant:
 567  * As per specification, 6.2.2.8: "When the parser encounters a main item it
 568  * concatenates the last declared Usage Page with a Usage to form a complete
 569  * usage value."
 570  */
 571 
 572 static void hid_concatenate_last_usage_page(struct hid_parser *parser)
 573 {
 574         int i;
 575         unsigned int usage_page;
 576         unsigned int current_page;
 577 
 578         if (!parser->local.usage_index)
 579                 return;
 580 
 581         usage_page = parser->global.usage_page;
 582 
 583         /*
 584          * Concatenate usage page again only if last declared Usage Page
 585          * has not been already used in previous usages concatenation
 586          */
 587         for (i = parser->local.usage_index - 1; i >= 0; i--) {
 588                 if (parser->local.usage_size[i] > 2)
 589                         /* Ignore extended usages */
 590                         continue;
 591 
 592                 current_page = parser->local.usage[i] >> 16;
 593                 if (current_page == usage_page)
 594                         break;
 595 
 596                 complete_usage(parser, i);
 597         }
 598 }
 599 
 600 /*
 601  * Process a main item.
 602  */
 603 
 604 static int hid_parser_main(struct hid_parser *parser, struct hid_item *item)
 605 {
 606         __u32 data;
 607         int ret;
 608 
 609         hid_concatenate_last_usage_page(parser);
 610 
 611         data = item_udata(item);
 612 
 613         switch (item->tag) {
 614         case HID_MAIN_ITEM_TAG_BEGIN_COLLECTION:
 615                 ret = open_collection(parser, data & 0xff);
 616                 break;
 617         case HID_MAIN_ITEM_TAG_END_COLLECTION:
 618                 ret = close_collection(parser);
 619                 break;
 620         case HID_MAIN_ITEM_TAG_INPUT:
 621                 ret = hid_add_field(parser, HID_INPUT_REPORT, data);
 622                 break;
 623         case HID_MAIN_ITEM_TAG_OUTPUT:
 624                 ret = hid_add_field(parser, HID_OUTPUT_REPORT, data);
 625                 break;
 626         case HID_MAIN_ITEM_TAG_FEATURE:
 627                 ret = hid_add_field(parser, HID_FEATURE_REPORT, data);
 628                 break;
 629         default:
 630                 hid_warn(parser->device, "unknown main item tag 0x%x\n", item->tag);
 631                 ret = 0;
 632         }
 633 
 634         memset(&parser->local, 0, sizeof(parser->local));       /* Reset the local parser environment */
 635 
 636         return ret;
 637 }
 638 
 639 /*
 640  * Process a reserved item.
 641  */
 642 
 643 static int hid_parser_reserved(struct hid_parser *parser, struct hid_item *item)
 644 {
 645         dbg_hid("reserved item type, tag 0x%x\n", item->tag);
 646         return 0;
 647 }
 648 
 649 /*
 650  * Free a report and all registered fields. The field->usage and
 651  * field->value table's are allocated behind the field, so we need
 652  * only to free(field) itself.
 653  */
 654 
 655 static void hid_free_report(struct hid_report *report)
 656 {
 657         unsigned n;
 658 
 659         for (n = 0; n < report->maxfield; n++)
 660                 kfree(report->field[n]);
 661         kfree(report);
 662 }
 663 
 664 /*
 665  * Close report. This function returns the device
 666  * state to the point prior to hid_open_report().
 667  */
 668 static void hid_close_report(struct hid_device *device)
 669 {
 670         unsigned i, j;
 671 
 672         for (i = 0; i < HID_REPORT_TYPES; i++) {
 673                 struct hid_report_enum *report_enum = device->report_enum + i;
 674 
 675                 for (j = 0; j < HID_MAX_IDS; j++) {
 676                         struct hid_report *report = report_enum->report_id_hash[j];
 677                         if (report)
 678                                 hid_free_report(report);
 679                 }
 680                 memset(report_enum, 0, sizeof(*report_enum));
 681                 INIT_LIST_HEAD(&report_enum->report_list);
 682         }
 683 
 684         kfree(device->rdesc);
 685         device->rdesc = NULL;
 686         device->rsize = 0;
 687 
 688         kfree(device->collection);
 689         device->collection = NULL;
 690         device->collection_size = 0;
 691         device->maxcollection = 0;
 692         device->maxapplication = 0;
 693 
 694         device->status &= ~HID_STAT_PARSED;
 695 }
 696 
 697 /*
 698  * Free a device structure, all reports, and all fields.
 699  */
 700 
 701 static void hid_device_release(struct device *dev)
 702 {
 703         struct hid_device *hid = to_hid_device(dev);
 704 
 705         hid_close_report(hid);
 706         kfree(hid->dev_rdesc);
 707         kfree(hid);
 708 }
 709 
 710 /*
 711  * Fetch a report description item from the data stream. We support long
 712  * items, though they are not used yet.
 713  */
 714 
 715 static u8 *fetch_item(__u8 *start, __u8 *end, struct hid_item *item)
 716 {
 717         u8 b;
 718 
 719         if ((end - start) <= 0)
 720                 return NULL;
 721 
 722         b = *start++;
 723 
 724         item->type = (b >> 2) & 3;
 725         item->tag  = (b >> 4) & 15;
 726 
 727         if (item->tag == HID_ITEM_TAG_LONG) {
 728 
 729                 item->format = HID_ITEM_FORMAT_LONG;
 730 
 731                 if ((end - start) < 2)
 732                         return NULL;
 733 
 734                 item->size = *start++;
 735                 item->tag  = *start++;
 736 
 737                 if ((end - start) < item->size)
 738                         return NULL;
 739 
 740                 item->data.longdata = start;
 741                 start += item->size;
 742                 return start;
 743         }
 744 
 745         item->format = HID_ITEM_FORMAT_SHORT;
 746         item->size = b & 3;
 747 
 748         switch (item->size) {
 749         case 0:
 750                 return start;
 751 
 752         case 1:
 753                 if ((end - start) < 1)
 754                         return NULL;
 755                 item->data.u8 = *start++;
 756                 return start;
 757 
 758         case 2:
 759                 if ((end - start) < 2)
 760                         return NULL;
 761                 item->data.u16 = get_unaligned_le16(start);
 762                 start = (__u8 *)((__le16 *)start + 1);
 763                 return start;
 764 
 765         case 3:
 766                 item->size++;
 767                 if ((end - start) < 4)
 768                         return NULL;
 769                 item->data.u32 = get_unaligned_le32(start);
 770                 start = (__u8 *)((__le32 *)start + 1);
 771                 return start;
 772         }
 773 
 774         return NULL;
 775 }
 776 
 777 static void hid_scan_input_usage(struct hid_parser *parser, u32 usage)
 778 {
 779         struct hid_device *hid = parser->device;
 780 
 781         if (usage == HID_DG_CONTACTID)
 782                 hid->group = HID_GROUP_MULTITOUCH;
 783 }
 784 
 785 static void hid_scan_feature_usage(struct hid_parser *parser, u32 usage)
 786 {
 787         if (usage == 0xff0000c5 && parser->global.report_count == 256 &&
 788             parser->global.report_size == 8)
 789                 parser->scan_flags |= HID_SCAN_FLAG_MT_WIN_8;
 790 
 791         if (usage == 0xff0000c6 && parser->global.report_count == 1 &&
 792             parser->global.report_size == 8)
 793                 parser->scan_flags |= HID_SCAN_FLAG_MT_WIN_8;
 794 }
 795 
 796 static void hid_scan_collection(struct hid_parser *parser, unsigned type)
 797 {
 798         struct hid_device *hid = parser->device;
 799         int i;
 800 
 801         if (((parser->global.usage_page << 16) == HID_UP_SENSOR) &&
 802             type == HID_COLLECTION_PHYSICAL)
 803                 hid->group = HID_GROUP_SENSOR_HUB;
 804 
 805         if (hid->vendor == USB_VENDOR_ID_MICROSOFT &&
 806             hid->product == USB_DEVICE_ID_MS_POWER_COVER &&
 807             hid->group == HID_GROUP_MULTITOUCH)
 808                 hid->group = HID_GROUP_GENERIC;
 809 
 810         if ((parser->global.usage_page << 16) == HID_UP_GENDESK)
 811                 for (i = 0; i < parser->local.usage_index; i++)
 812                         if (parser->local.usage[i] == HID_GD_POINTER)
 813                                 parser->scan_flags |= HID_SCAN_FLAG_GD_POINTER;
 814 
 815         if ((parser->global.usage_page << 16) >= HID_UP_MSVENDOR)
 816                 parser->scan_flags |= HID_SCAN_FLAG_VENDOR_SPECIFIC;
 817 }
 818 
 819 static int hid_scan_main(struct hid_parser *parser, struct hid_item *item)
 820 {
 821         __u32 data;
 822         int i;
 823 
 824         hid_concatenate_last_usage_page(parser);
 825 
 826         data = item_udata(item);
 827 
 828         switch (item->tag) {
 829         case HID_MAIN_ITEM_TAG_BEGIN_COLLECTION:
 830                 hid_scan_collection(parser, data & 0xff);
 831                 break;
 832         case HID_MAIN_ITEM_TAG_END_COLLECTION:
 833                 break;
 834         case HID_MAIN_ITEM_TAG_INPUT:
 835                 /* ignore constant inputs, they will be ignored by hid-input */
 836                 if (data & HID_MAIN_ITEM_CONSTANT)
 837                         break;
 838                 for (i = 0; i < parser->local.usage_index; i++)
 839                         hid_scan_input_usage(parser, parser->local.usage[i]);
 840                 break;
 841         case HID_MAIN_ITEM_TAG_OUTPUT:
 842                 break;
 843         case HID_MAIN_ITEM_TAG_FEATURE:
 844                 for (i = 0; i < parser->local.usage_index; i++)
 845                         hid_scan_feature_usage(parser, parser->local.usage[i]);
 846                 break;
 847         }
 848 
 849         /* Reset the local parser environment */
 850         memset(&parser->local, 0, sizeof(parser->local));
 851 
 852         return 0;
 853 }
 854 
 855 /*
 856  * Scan a report descriptor before the device is added to the bus.
 857  * Sets device groups and other properties that determine what driver
 858  * to load.
 859  */
 860 static int hid_scan_report(struct hid_device *hid)
 861 {
 862         struct hid_parser *parser;
 863         struct hid_item item;
 864         __u8 *start = hid->dev_rdesc;
 865         __u8 *end = start + hid->dev_rsize;
 866         static int (*dispatch_type[])(struct hid_parser *parser,
 867                                       struct hid_item *item) = {
 868                 hid_scan_main,
 869                 hid_parser_global,
 870                 hid_parser_local,
 871                 hid_parser_reserved
 872         };
 873 
 874         parser = vzalloc(sizeof(struct hid_parser));
 875         if (!parser)
 876                 return -ENOMEM;
 877 
 878         parser->device = hid;
 879         hid->group = HID_GROUP_GENERIC;
 880 
 881         /*
 882          * The parsing is simpler than the one in hid_open_report() as we should
 883          * be robust against hid errors. Those errors will be raised by
 884          * hid_open_report() anyway.
 885          */
 886         while ((start = fetch_item(start, end, &item)) != NULL)
 887                 dispatch_type[item.type](parser, &item);
 888 
 889         /*
 890          * Handle special flags set during scanning.
 891          */
 892         if ((parser->scan_flags & HID_SCAN_FLAG_MT_WIN_8) &&
 893             (hid->group == HID_GROUP_MULTITOUCH))
 894                 hid->group = HID_GROUP_MULTITOUCH_WIN_8;
 895 
 896         /*
 897          * Vendor specific handlings
 898          */
 899         switch (hid->vendor) {
 900         case USB_VENDOR_ID_WACOM:
 901                 hid->group = HID_GROUP_WACOM;
 902                 break;
 903         case USB_VENDOR_ID_SYNAPTICS:
 904                 if (hid->group == HID_GROUP_GENERIC)
 905                         if ((parser->scan_flags & HID_SCAN_FLAG_VENDOR_SPECIFIC)
 906                             && (parser->scan_flags & HID_SCAN_FLAG_GD_POINTER))
 907                                 /*
 908                                  * hid-rmi should take care of them,
 909                                  * not hid-generic
 910                                  */
 911                                 hid->group = HID_GROUP_RMI;
 912                 break;
 913         }
 914 
 915         kfree(parser->collection_stack);
 916         vfree(parser);
 917         return 0;
 918 }
 919 
 920 /**
 921  * hid_parse_report - parse device report
 922  *
 923  * @device: hid device
 924  * @start: report start
 925  * @size: report size
 926  *
 927  * Allocate the device report as read by the bus driver. This function should
 928  * only be called from parse() in ll drivers.
 929  */
 930 int hid_parse_report(struct hid_device *hid, __u8 *start, unsigned size)
 931 {
 932         hid->dev_rdesc = kmemdup(start, size, GFP_KERNEL);
 933         if (!hid->dev_rdesc)
 934                 return -ENOMEM;
 935         hid->dev_rsize = size;
 936         return 0;
 937 }
 938 EXPORT_SYMBOL_GPL(hid_parse_report);
 939 
 940 static const char * const hid_report_names[] = {
 941         "HID_INPUT_REPORT",
 942         "HID_OUTPUT_REPORT",
 943         "HID_FEATURE_REPORT",
 944 };
 945 /**
 946  * hid_validate_values - validate existing device report's value indexes
 947  *
 948  * @device: hid device
 949  * @type: which report type to examine
 950  * @id: which report ID to examine (0 for first)
 951  * @field_index: which report field to examine
 952  * @report_counts: expected number of values
 953  *
 954  * Validate the number of values in a given field of a given report, after
 955  * parsing.
 956  */
 957 struct hid_report *hid_validate_values(struct hid_device *hid,
 958                                        unsigned int type, unsigned int id,
 959                                        unsigned int field_index,
 960                                        unsigned int report_counts)
 961 {
 962         struct hid_report *report;
 963 
 964         if (type > HID_FEATURE_REPORT) {
 965                 hid_err(hid, "invalid HID report type %u\n", type);
 966                 return NULL;
 967         }
 968 
 969         if (id >= HID_MAX_IDS) {
 970                 hid_err(hid, "invalid HID report id %u\n", id);
 971                 return NULL;
 972         }
 973 
 974         /*
 975          * Explicitly not using hid_get_report() here since it depends on
 976          * ->numbered being checked, which may not always be the case when
 977          * drivers go to access report values.
 978          */
 979         if (id == 0) {
 980                 /*
 981                  * Validating on id 0 means we should examine the first
 982                  * report in the list.
 983                  */
 984                 report = list_entry(
 985                                 hid->report_enum[type].report_list.next,
 986                                 struct hid_report, list);
 987         } else {
 988                 report = hid->report_enum[type].report_id_hash[id];
 989         }
 990         if (!report) {
 991                 hid_err(hid, "missing %s %u\n", hid_report_names[type], id);
 992                 return NULL;
 993         }
 994         if (report->maxfield <= field_index) {
 995                 hid_err(hid, "not enough fields in %s %u\n",
 996                         hid_report_names[type], id);
 997                 return NULL;
 998         }
 999         if (report->field[field_index]->report_count < report_counts) {
1000                 hid_err(hid, "not enough values in %s %u field %u\n",
1001                         hid_report_names[type], id, field_index);
1002                 return NULL;
1003         }
1004         return report;
1005 }
1006 EXPORT_SYMBOL_GPL(hid_validate_values);
1007 
1008 static int hid_calculate_multiplier(struct hid_device *hid,
1009                                      struct hid_field *multiplier)
1010 {
1011         int m;
1012         __s32 v = *multiplier->value;
1013         __s32 lmin = multiplier->logical_minimum;
1014         __s32 lmax = multiplier->logical_maximum;
1015         __s32 pmin = multiplier->physical_minimum;
1016         __s32 pmax = multiplier->physical_maximum;
1017 
1018         /*
1019          * "Because OS implementations will generally divide the control's
1020          * reported count by the Effective Resolution Multiplier, designers
1021          * should take care not to establish a potential Effective
1022          * Resolution Multiplier of zero."
1023          * HID Usage Table, v1.12, Section 4.3.1, p31
1024          */
1025         if (lmax - lmin == 0)
1026                 return 1;
1027         /*
1028          * Handling the unit exponent is left as an exercise to whoever
1029          * finds a device where that exponent is not 0.
1030          */
1031         m = ((v - lmin)/(lmax - lmin) * (pmax - pmin) + pmin);
1032         if (unlikely(multiplier->unit_exponent != 0)) {
1033                 hid_warn(hid,
1034                          "unsupported Resolution Multiplier unit exponent %d\n",
1035                          multiplier->unit_exponent);
1036         }
1037 
1038         /* There are no devices with an effective multiplier > 255 */
1039         if (unlikely(m == 0 || m > 255 || m < -255)) {
1040                 hid_warn(hid, "unsupported Resolution Multiplier %d\n", m);
1041                 m = 1;
1042         }
1043 
1044         return m;
1045 }
1046 
1047 static void hid_apply_multiplier_to_field(struct hid_device *hid,
1048                                           struct hid_field *field,
1049                                           struct hid_collection *multiplier_collection,
1050                                           int effective_multiplier)
1051 {
1052         struct hid_collection *collection;
1053         struct hid_usage *usage;
1054         int i;
1055 
1056         /*
1057          * If multiplier_collection is NULL, the multiplier applies
1058          * to all fields in the report.
1059          * Otherwise, it is the Logical Collection the multiplier applies to
1060          * but our field may be in a subcollection of that collection.
1061          */
1062         for (i = 0; i < field->maxusage; i++) {
1063                 usage = &field->usage[i];
1064 
1065                 collection = &hid->collection[usage->collection_index];
1066                 while (collection->parent_idx != -1 &&
1067                        collection != multiplier_collection)
1068                         collection = &hid->collection[collection->parent_idx];
1069 
1070                 if (collection->parent_idx != -1 ||
1071                     multiplier_collection == NULL)
1072                         usage->resolution_multiplier = effective_multiplier;
1073 
1074         }
1075 }
1076 
1077 static void hid_apply_multiplier(struct hid_device *hid,
1078                                  struct hid_field *multiplier)
1079 {
1080         struct hid_report_enum *rep_enum;
1081         struct hid_report *rep;
1082         struct hid_field *field;
1083         struct hid_collection *multiplier_collection;
1084         int effective_multiplier;
1085         int i;
1086 
1087         /*
1088          * "The Resolution Multiplier control must be contained in the same
1089          * Logical Collection as the control(s) to which it is to be applied.
1090          * If no Resolution Multiplier is defined, then the Resolution
1091          * Multiplier defaults to 1.  If more than one control exists in a
1092          * Logical Collection, the Resolution Multiplier is associated with
1093          * all controls in the collection. If no Logical Collection is
1094          * defined, the Resolution Multiplier is associated with all
1095          * controls in the report."
1096          * HID Usage Table, v1.12, Section 4.3.1, p30
1097          *
1098          * Thus, search from the current collection upwards until we find a
1099          * logical collection. Then search all fields for that same parent
1100          * collection. Those are the fields the multiplier applies to.
1101          *
1102          * If we have more than one multiplier, it will overwrite the
1103          * applicable fields later.
1104          */
1105         multiplier_collection = &hid->collection[multiplier->usage->collection_index];
1106         while (multiplier_collection->parent_idx != -1 &&
1107                multiplier_collection->type != HID_COLLECTION_LOGICAL)
1108                 multiplier_collection = &hid->collection[multiplier_collection->parent_idx];
1109 
1110         effective_multiplier = hid_calculate_multiplier(hid, multiplier);
1111 
1112         rep_enum = &hid->report_enum[HID_INPUT_REPORT];
1113         list_for_each_entry(rep, &rep_enum->report_list, list) {
1114                 for (i = 0; i < rep->maxfield; i++) {
1115                         field = rep->field[i];
1116                         hid_apply_multiplier_to_field(hid, field,
1117                                                       multiplier_collection,
1118                                                       effective_multiplier);
1119                 }
1120         }
1121 }
1122 
1123 /*
1124  * hid_setup_resolution_multiplier - set up all resolution multipliers
1125  *
1126  * @device: hid device
1127  *
1128  * Search for all Resolution Multiplier Feature Reports and apply their
1129  * value to all matching Input items. This only updates the internal struct
1130  * fields.
1131  *
1132  * The Resolution Multiplier is applied by the hardware. If the multiplier
1133  * is anything other than 1, the hardware will send pre-multiplied events
1134  * so that the same physical interaction generates an accumulated
1135  *      accumulated_value = value * * multiplier
1136  * This may be achieved by sending
1137  * - "value * multiplier" for each event, or
1138  * - "value" but "multiplier" times as frequently, or
1139  * - a combination of the above
1140  * The only guarantee is that the same physical interaction always generates
1141  * an accumulated 'value * multiplier'.
1142  *
1143  * This function must be called before any event processing and after
1144  * any SetRequest to the Resolution Multiplier.
1145  */
1146 void hid_setup_resolution_multiplier(struct hid_device *hid)
1147 {
1148         struct hid_report_enum *rep_enum;
1149         struct hid_report *rep;
1150         struct hid_usage *usage;
1151         int i, j;
1152 
1153         rep_enum = &hid->report_enum[HID_FEATURE_REPORT];
1154         list_for_each_entry(rep, &rep_enum->report_list, list) {
1155                 for (i = 0; i < rep->maxfield; i++) {
1156                         /* Ignore if report count is out of bounds. */
1157                         if (rep->field[i]->report_count < 1)
1158                                 continue;
1159 
1160                         for (j = 0; j < rep->field[i]->maxusage; j++) {
1161                                 usage = &rep->field[i]->usage[j];
1162                                 if (usage->hid == HID_GD_RESOLUTION_MULTIPLIER)
1163                                         hid_apply_multiplier(hid,
1164                                                              rep->field[i]);
1165                         }
1166                 }
1167         }
1168 }
1169 EXPORT_SYMBOL_GPL(hid_setup_resolution_multiplier);
1170 
1171 /**
1172  * hid_open_report - open a driver-specific device report
1173  *
1174  * @device: hid device
1175  *
1176  * Parse a report description into a hid_device structure. Reports are
1177  * enumerated, fields are attached to these reports.
1178  * 0 returned on success, otherwise nonzero error value.
1179  *
1180  * This function (or the equivalent hid_parse() macro) should only be
1181  * called from probe() in drivers, before starting the device.
1182  */
1183 int hid_open_report(struct hid_device *device)
1184 {
1185         struct hid_parser *parser;
1186         struct hid_item item;
1187         unsigned int size;
1188         __u8 *start;
1189         __u8 *buf;
1190         __u8 *end;
1191         __u8 *next;
1192         int ret;
1193         static int (*dispatch_type[])(struct hid_parser *parser,
1194                                       struct hid_item *item) = {
1195                 hid_parser_main,
1196                 hid_parser_global,
1197                 hid_parser_local,
1198                 hid_parser_reserved
1199         };
1200 
1201         if (WARN_ON(device->status & HID_STAT_PARSED))
1202                 return -EBUSY;
1203 
1204         start = device->dev_rdesc;
1205         if (WARN_ON(!start))
1206                 return -ENODEV;
1207         size = device->dev_rsize;
1208 
1209         buf = kmemdup(start, size, GFP_KERNEL);
1210         if (buf == NULL)
1211                 return -ENOMEM;
1212 
1213         if (device->driver->report_fixup)
1214                 start = device->driver->report_fixup(device, buf, &size);
1215         else
1216                 start = buf;
1217 
1218         start = kmemdup(start, size, GFP_KERNEL);
1219         kfree(buf);
1220         if (start == NULL)
1221                 return -ENOMEM;
1222 
1223         device->rdesc = start;
1224         device->rsize = size;
1225 
1226         parser = vzalloc(sizeof(struct hid_parser));
1227         if (!parser) {
1228                 ret = -ENOMEM;
1229                 goto alloc_err;
1230         }
1231 
1232         parser->device = device;
1233 
1234         end = start + size;
1235 
1236         device->collection = kcalloc(HID_DEFAULT_NUM_COLLECTIONS,
1237                                      sizeof(struct hid_collection), GFP_KERNEL);
1238         if (!device->collection) {
1239                 ret = -ENOMEM;
1240                 goto err;
1241         }
1242         device->collection_size = HID_DEFAULT_NUM_COLLECTIONS;
1243 
1244         ret = -EINVAL;
1245         while ((next = fetch_item(start, end, &item)) != NULL) {
1246                 start = next;
1247 
1248                 if (item.format != HID_ITEM_FORMAT_SHORT) {
1249                         hid_err(device, "unexpected long global item\n");
1250                         goto err;
1251                 }
1252 
1253                 if (dispatch_type[item.type](parser, &item)) {
1254                         hid_err(device, "item %u %u %u %u parsing failed\n",
1255                                 item.format, (unsigned)item.size,
1256                                 (unsigned)item.type, (unsigned)item.tag);
1257                         goto err;
1258                 }
1259 
1260                 if (start == end) {
1261                         if (parser->collection_stack_ptr) {
1262                                 hid_err(device, "unbalanced collection at end of report description\n");
1263                                 goto err;
1264                         }
1265                         if (parser->local.delimiter_depth) {
1266                                 hid_err(device, "unbalanced delimiter at end of report description\n");
1267                                 goto err;
1268                         }
1269 
1270                         /*
1271                          * fetch initial values in case the device's
1272                          * default multiplier isn't the recommended 1
1273                          */
1274                         hid_setup_resolution_multiplier(device);
1275 
1276                         kfree(parser->collection_stack);
1277                         vfree(parser);
1278                         device->status |= HID_STAT_PARSED;
1279 
1280                         return 0;
1281                 }
1282         }
1283 
1284         hid_err(device, "item fetching failed at offset %u/%u\n",
1285                 size - (unsigned int)(end - start), size);
1286 err:
1287         kfree(parser->collection_stack);
1288 alloc_err:
1289         vfree(parser);
1290         hid_close_report(device);
1291         return ret;
1292 }
1293 EXPORT_SYMBOL_GPL(hid_open_report);
1294 
1295 /*
1296  * Convert a signed n-bit integer to signed 32-bit integer. Common
1297  * cases are done through the compiler, the screwed things has to be
1298  * done by hand.
1299  */
1300 
1301 static s32 snto32(__u32 value, unsigned n)
1302 {
1303         switch (n) {
1304         case 8:  return ((__s8)value);
1305         case 16: return ((__s16)value);
1306         case 32: return ((__s32)value);
1307         }
1308         return value & (1 << (n - 1)) ? value | (~0U << n) : value;
1309 }
1310 
1311 s32 hid_snto32(__u32 value, unsigned n)
1312 {
1313         return snto32(value, n);
1314 }
1315 EXPORT_SYMBOL_GPL(hid_snto32);
1316 
1317 /*
1318  * Convert a signed 32-bit integer to a signed n-bit integer.
1319  */
1320 
1321 static u32 s32ton(__s32 value, unsigned n)
1322 {
1323         s32 a = value >> (n - 1);
1324         if (a && a != -1)
1325                 return value < 0 ? 1 << (n - 1) : (1 << (n - 1)) - 1;
1326         return value & ((1 << n) - 1);
1327 }
1328 
1329 /*
1330  * Extract/implement a data field from/to a little endian report (bit array).
1331  *
1332  * Code sort-of follows HID spec:
1333  *     http://www.usb.org/developers/hidpage/HID1_11.pdf
1334  *
1335  * While the USB HID spec allows unlimited length bit fields in "report
1336  * descriptors", most devices never use more than 16 bits.
1337  * One model of UPS is claimed to report "LINEV" as a 32-bit field.
1338  * Search linux-kernel and linux-usb-devel archives for "hid-core extract".
1339  */
1340 
1341 static u32 __extract(u8 *report, unsigned offset, int n)
1342 {
1343         unsigned int idx = offset / 8;
1344         unsigned int bit_nr = 0;
1345         unsigned int bit_shift = offset % 8;
1346         int bits_to_copy = 8 - bit_shift;
1347         u32 value = 0;
1348         u32 mask = n < 32 ? (1U << n) - 1 : ~0U;
1349 
1350         while (n > 0) {
1351                 value |= ((u32)report[idx] >> bit_shift) << bit_nr;
1352                 n -= bits_to_copy;
1353                 bit_nr += bits_to_copy;
1354                 bits_to_copy = 8;
1355                 bit_shift = 0;
1356                 idx++;
1357         }
1358 
1359         return value & mask;
1360 }
1361 
1362 u32 hid_field_extract(const struct hid_device *hid, u8 *report,
1363                         unsigned offset, unsigned n)
1364 {
1365         if (n > 32) {
1366                 hid_warn_once(hid, "%s() called with n (%d) > 32! (%s)\n",
1367                               __func__, n, current->comm);
1368                 n = 32;
1369         }
1370 
1371         return __extract(report, offset, n);
1372 }
1373 EXPORT_SYMBOL_GPL(hid_field_extract);
1374 
1375 /*
1376  * "implement" : set bits in a little endian bit stream.
1377  * Same concepts as "extract" (see comments above).
1378  * The data mangled in the bit stream remains in little endian
1379  * order the whole time. It make more sense to talk about
1380  * endianness of register values by considering a register
1381  * a "cached" copy of the little endian bit stream.
1382  */
1383 
1384 static void __implement(u8 *report, unsigned offset, int n, u32 value)
1385 {
1386         unsigned int idx = offset / 8;
1387         unsigned int bit_shift = offset % 8;
1388         int bits_to_set = 8 - bit_shift;
1389 
1390         while (n - bits_to_set >= 0) {
1391                 report[idx] &= ~(0xff << bit_shift);
1392                 report[idx] |= value << bit_shift;
1393                 value >>= bits_to_set;
1394                 n -= bits_to_set;
1395                 bits_to_set = 8;
1396                 bit_shift = 0;
1397                 idx++;
1398         }
1399 
1400         /* last nibble */
1401         if (n) {
1402                 u8 bit_mask = ((1U << n) - 1);
1403                 report[idx] &= ~(bit_mask << bit_shift);
1404                 report[idx] |= value << bit_shift;
1405         }
1406 }
1407 
1408 static void implement(const struct hid_device *hid, u8 *report,
1409                       unsigned offset, unsigned n, u32 value)
1410 {
1411         if (unlikely(n > 32)) {
1412                 hid_warn(hid, "%s() called with n (%d) > 32! (%s)\n",
1413                          __func__, n, current->comm);
1414                 n = 32;
1415         } else if (n < 32) {
1416                 u32 m = (1U << n) - 1;
1417 
1418                 if (unlikely(value > m)) {
1419                         hid_warn(hid,
1420                                  "%s() called with too large value %d (n: %d)! (%s)\n",
1421                                  __func__, value, n, current->comm);
1422                         WARN_ON(1);
1423                         value &= m;
1424                 }
1425         }
1426 
1427         __implement(report, offset, n, value);
1428 }
1429 
1430 /*
1431  * Search an array for a value.
1432  */
1433 
1434 static int search(__s32 *array, __s32 value, unsigned n)
1435 {
1436         while (n--) {
1437                 if (*array++ == value)
1438                         return 0;
1439         }
1440         return -1;
1441 }
1442 
1443 /**
1444  * hid_match_report - check if driver's raw_event should be called
1445  *
1446  * @hid: hid device
1447  * @report_type: type to match against
1448  *
1449  * compare hid->driver->report_table->report_type to report->type
1450  */
1451 static int hid_match_report(struct hid_device *hid, struct hid_report *report)
1452 {
1453         const struct hid_report_id *id = hid->driver->report_table;
1454 
1455         if (!id) /* NULL means all */
1456                 return 1;
1457 
1458         for (; id->report_type != HID_TERMINATOR; id++)
1459                 if (id->report_type == HID_ANY_ID ||
1460                                 id->report_type == report->type)
1461                         return 1;
1462         return 0;
1463 }
1464 
1465 /**
1466  * hid_match_usage - check if driver's event should be called
1467  *
1468  * @hid: hid device
1469  * @usage: usage to match against
1470  *
1471  * compare hid->driver->usage_table->usage_{type,code} to
1472  * usage->usage_{type,code}
1473  */
1474 static int hid_match_usage(struct hid_device *hid, struct hid_usage *usage)
1475 {
1476         const struct hid_usage_id *id = hid->driver->usage_table;
1477 
1478         if (!id) /* NULL means all */
1479                 return 1;
1480 
1481         for (; id->usage_type != HID_ANY_ID - 1; id++)
1482                 if ((id->usage_hid == HID_ANY_ID ||
1483                                 id->usage_hid == usage->hid) &&
1484                                 (id->usage_type == HID_ANY_ID ||
1485                                 id->usage_type == usage->type) &&
1486                                 (id->usage_code == HID_ANY_ID ||
1487                                  id->usage_code == usage->code))
1488                         return 1;
1489         return 0;
1490 }
1491 
1492 static void hid_process_event(struct hid_device *hid, struct hid_field *field,
1493                 struct hid_usage *usage, __s32 value, int interrupt)
1494 {
1495         struct hid_driver *hdrv = hid->driver;
1496         int ret;
1497 
1498         if (!list_empty(&hid->debug_list))
1499                 hid_dump_input(hid, usage, value);
1500 
1501         if (hdrv && hdrv->event && hid_match_usage(hid, usage)) {
1502                 ret = hdrv->event(hid, field, usage, value);
1503                 if (ret != 0) {
1504                         if (ret < 0)
1505                                 hid_err(hid, "%s's event failed with %d\n",
1506                                                 hdrv->name, ret);
1507                         return;
1508                 }
1509         }
1510 
1511         if (hid->claimed & HID_CLAIMED_INPUT)
1512                 hidinput_hid_event(hid, field, usage, value);
1513         if (hid->claimed & HID_CLAIMED_HIDDEV && interrupt && hid->hiddev_hid_event)
1514                 hid->hiddev_hid_event(hid, field, usage, value);
1515 }
1516 
1517 /*
1518  * Analyse a received field, and fetch the data from it. The field
1519  * content is stored for next report processing (we do differential
1520  * reporting to the layer).
1521  */
1522 
1523 static void hid_input_field(struct hid_device *hid, struct hid_field *field,
1524                             __u8 *data, int interrupt)
1525 {
1526         unsigned n;
1527         unsigned count = field->report_count;
1528         unsigned offset = field->report_offset;
1529         unsigned size = field->report_size;
1530         __s32 min = field->logical_minimum;
1531         __s32 max = field->logical_maximum;
1532         __s32 *value;
1533 
1534         value = kmalloc_array(count, sizeof(__s32), GFP_ATOMIC);
1535         if (!value)
1536                 return;
1537 
1538         for (n = 0; n < count; n++) {
1539 
1540                 value[n] = min < 0 ?
1541                         snto32(hid_field_extract(hid, data, offset + n * size,
1542                                size), size) :
1543                         hid_field_extract(hid, data, offset + n * size, size);
1544 
1545                 /* Ignore report if ErrorRollOver */
1546                 if (!(field->flags & HID_MAIN_ITEM_VARIABLE) &&
1547                     value[n] >= min && value[n] <= max &&
1548                     value[n] - min < field->maxusage &&
1549                     field->usage[value[n] - min].hid == HID_UP_KEYBOARD + 1)
1550                         goto exit;
1551         }
1552 
1553         for (n = 0; n < count; n++) {
1554 
1555                 if (HID_MAIN_ITEM_VARIABLE & field->flags) {
1556                         hid_process_event(hid, field, &field->usage[n], value[n], interrupt);
1557                         continue;
1558                 }
1559 
1560                 if (field->value[n] >= min && field->value[n] <= max
1561                         && field->value[n] - min < field->maxusage
1562                         && field->usage[field->value[n] - min].hid
1563                         && search(value, field->value[n], count))
1564                                 hid_process_event(hid, field, &field->usage[field->value[n] - min], 0, interrupt);
1565 
1566                 if (value[n] >= min && value[n] <= max
1567                         && value[n] - min < field->maxusage
1568                         && field->usage[value[n] - min].hid
1569                         && search(field->value, value[n], count))
1570                                 hid_process_event(hid, field, &field->usage[value[n] - min], 1, interrupt);
1571         }
1572 
1573         memcpy(field->value, value, count * sizeof(__s32));
1574 exit:
1575         kfree(value);
1576 }
1577 
1578 /*
1579  * Output the field into the report.
1580  */
1581 
1582 static void hid_output_field(const struct hid_device *hid,
1583                              struct hid_field *field, __u8 *data)
1584 {
1585         unsigned count = field->report_count;
1586         unsigned offset = field->report_offset;
1587         unsigned size = field->report_size;
1588         unsigned n;
1589 
1590         for (n = 0; n < count; n++) {
1591                 if (field->logical_minimum < 0) /* signed values */
1592                         implement(hid, data, offset + n * size, size,
1593                                   s32ton(field->value[n], size));
1594                 else                            /* unsigned values */
1595                         implement(hid, data, offset + n * size, size,
1596                                   field->value[n]);
1597         }
1598 }
1599 
1600 /*
1601  * Create a report. 'data' has to be allocated using
1602  * hid_alloc_report_buf() so that it has proper size.
1603  */
1604 
1605 void hid_output_report(struct hid_report *report, __u8 *data)
1606 {
1607         unsigned n;
1608 
1609         if (report->id > 0)
1610                 *data++ = report->id;
1611 
1612         memset(data, 0, ((report->size - 1) >> 3) + 1);
1613         for (n = 0; n < report->maxfield; n++)
1614                 hid_output_field(report->device, report->field[n], data);
1615 }
1616 EXPORT_SYMBOL_GPL(hid_output_report);
1617 
1618 /*
1619  * Allocator for buffer that is going to be passed to hid_output_report()
1620  */
1621 u8 *hid_alloc_report_buf(struct hid_report *report, gfp_t flags)
1622 {
1623         /*
1624          * 7 extra bytes are necessary to achieve proper functionality
1625          * of implement() working on 8 byte chunks
1626          */
1627 
1628         u32 len = hid_report_len(report) + 7;
1629 
1630         return kmalloc(len, flags);
1631 }
1632 EXPORT_SYMBOL_GPL(hid_alloc_report_buf);
1633 
1634 /*
1635  * Set a field value. The report this field belongs to has to be
1636  * created and transferred to the device, to set this value in the
1637  * device.
1638  */
1639 
1640 int hid_set_field(struct hid_field *field, unsigned offset, __s32 value)
1641 {
1642         unsigned size;
1643 
1644         if (!field)
1645                 return -1;
1646 
1647         size = field->report_size;
1648 
1649         hid_dump_input(field->report->device, field->usage + offset, value);
1650 
1651         if (offset >= field->report_count) {
1652                 hid_err(field->report->device, "offset (%d) exceeds report_count (%d)\n",
1653                                 offset, field->report_count);
1654                 return -1;
1655         }
1656         if (field->logical_minimum < 0) {
1657                 if (value != snto32(s32ton(value, size), size)) {
1658                         hid_err(field->report->device, "value %d is out of range\n", value);
1659                         return -1;
1660                 }
1661         }
1662         field->value[offset] = value;
1663         return 0;
1664 }
1665 EXPORT_SYMBOL_GPL(hid_set_field);
1666 
1667 static struct hid_report *hid_get_report(struct hid_report_enum *report_enum,
1668                 const u8 *data)
1669 {
1670         struct hid_report *report;
1671         unsigned int n = 0;     /* Normally report number is 0 */
1672 
1673         /* Device uses numbered reports, data[0] is report number */
1674         if (report_enum->numbered)
1675                 n = *data;
1676 
1677         report = report_enum->report_id_hash[n];
1678         if (report == NULL)
1679                 dbg_hid("undefined report_id %u received\n", n);
1680 
1681         return report;
1682 }
1683 
1684 /*
1685  * Implement a generic .request() callback, using .raw_request()
1686  * DO NOT USE in hid drivers directly, but through hid_hw_request instead.
1687  */
1688 int __hid_request(struct hid_device *hid, struct hid_report *report,
1689                 int reqtype)
1690 {
1691         char *buf;
1692         int ret;
1693         u32 len;
1694 
1695         buf = hid_alloc_report_buf(report, GFP_KERNEL);
1696         if (!buf)
1697                 return -ENOMEM;
1698 
1699         len = hid_report_len(report);
1700 
1701         if (reqtype == HID_REQ_SET_REPORT)
1702                 hid_output_report(report, buf);
1703 
1704         ret = hid->ll_driver->raw_request(hid, report->id, buf, len,
1705                                           report->type, reqtype);
1706         if (ret < 0) {
1707                 dbg_hid("unable to complete request: %d\n", ret);
1708                 goto out;
1709         }
1710 
1711         if (reqtype == HID_REQ_GET_REPORT)
1712                 hid_input_report(hid, report->type, buf, ret, 0);
1713 
1714         ret = 0;
1715 
1716 out:
1717         kfree(buf);
1718         return ret;
1719 }
1720 EXPORT_SYMBOL_GPL(__hid_request);
1721 
1722 int hid_report_raw_event(struct hid_device *hid, int type, u8 *data, u32 size,
1723                 int interrupt)
1724 {
1725         struct hid_report_enum *report_enum = hid->report_enum + type;
1726         struct hid_report *report;
1727         struct hid_driver *hdrv;
1728         unsigned int a;
1729         u32 rsize, csize = size;
1730         u8 *cdata = data;
1731         int ret = 0;
1732 
1733         report = hid_get_report(report_enum, data);
1734         if (!report)
1735                 goto out;
1736 
1737         if (report_enum->numbered) {
1738                 cdata++;
1739                 csize--;
1740         }
1741 
1742         rsize = ((report->size - 1) >> 3) + 1;
1743 
1744         if (report_enum->numbered && rsize >= HID_MAX_BUFFER_SIZE)
1745                 rsize = HID_MAX_BUFFER_SIZE - 1;
1746         else if (rsize > HID_MAX_BUFFER_SIZE)
1747                 rsize = HID_MAX_BUFFER_SIZE;
1748 
1749         if (csize < rsize) {
1750                 dbg_hid("report %d is too short, (%d < %d)\n", report->id,
1751                                 csize, rsize);
1752                 memset(cdata + csize, 0, rsize - csize);
1753         }
1754 
1755         if ((hid->claimed & HID_CLAIMED_HIDDEV) && hid->hiddev_report_event)
1756                 hid->hiddev_report_event(hid, report);
1757         if (hid->claimed & HID_CLAIMED_HIDRAW) {
1758                 ret = hidraw_report_event(hid, data, size);
1759                 if (ret)
1760                         goto out;
1761         }
1762 
1763         if (hid->claimed != HID_CLAIMED_HIDRAW && report->maxfield) {
1764                 for (a = 0; a < report->maxfield; a++)
1765                         hid_input_field(hid, report->field[a], cdata, interrupt);
1766                 hdrv = hid->driver;
1767                 if (hdrv && hdrv->report)
1768                         hdrv->report(hid, report);
1769         }
1770 
1771         if (hid->claimed & HID_CLAIMED_INPUT)
1772                 hidinput_report_event(hid, report);
1773 out:
1774         return ret;
1775 }
1776 EXPORT_SYMBOL_GPL(hid_report_raw_event);
1777 
1778 /**
1779  * hid_input_report - report data from lower layer (usb, bt...)
1780  *
1781  * @hid: hid device
1782  * @type: HID report type (HID_*_REPORT)
1783  * @data: report contents
1784  * @size: size of data parameter
1785  * @interrupt: distinguish between interrupt and control transfers
1786  *
1787  * This is data entry for lower layers.
1788  */
1789 int hid_input_report(struct hid_device *hid, int type, u8 *data, u32 size, int interrupt)
1790 {
1791         struct hid_report_enum *report_enum;
1792         struct hid_driver *hdrv;
1793         struct hid_report *report;
1794         int ret = 0;
1795 
1796         if (!hid)
1797                 return -ENODEV;
1798 
1799         if (down_trylock(&hid->driver_input_lock))
1800                 return -EBUSY;
1801 
1802         if (!hid->driver) {
1803                 ret = -ENODEV;
1804                 goto unlock;
1805         }
1806         report_enum = hid->report_enum + type;
1807         hdrv = hid->driver;
1808 
1809         if (!size) {
1810                 dbg_hid("empty report\n");
1811                 ret = -1;
1812                 goto unlock;
1813         }
1814 
1815         /* Avoid unnecessary overhead if debugfs is disabled */
1816         if (!list_empty(&hid->debug_list))
1817                 hid_dump_report(hid, type, data, size);
1818 
1819         report = hid_get_report(report_enum, data);
1820 
1821         if (!report) {
1822                 ret = -1;
1823                 goto unlock;
1824         }
1825 
1826         if (hdrv && hdrv->raw_event && hid_match_report(hid, report)) {
1827                 ret = hdrv->raw_event(hid, report, data, size);
1828                 if (ret < 0)
1829                         goto unlock;
1830         }
1831 
1832         ret = hid_report_raw_event(hid, type, data, size, interrupt);
1833 
1834 unlock:
1835         up(&hid->driver_input_lock);
1836         return ret;
1837 }
1838 EXPORT_SYMBOL_GPL(hid_input_report);
1839 
1840 bool hid_match_one_id(const struct hid_device *hdev,
1841                       const struct hid_device_id *id)
1842 {
1843         return (id->bus == HID_BUS_ANY || id->bus == hdev->bus) &&
1844                 (id->group == HID_GROUP_ANY || id->group == hdev->group) &&
1845                 (id->vendor == HID_ANY_ID || id->vendor == hdev->vendor) &&
1846                 (id->product == HID_ANY_ID || id->product == hdev->product);
1847 }
1848 
1849 const struct hid_device_id *hid_match_id(const struct hid_device *hdev,
1850                 const struct hid_device_id *id)
1851 {
1852         for (; id->bus; id++)
1853                 if (hid_match_one_id(hdev, id))
1854                         return id;
1855 
1856         return NULL;
1857 }
1858 
1859 static const struct hid_device_id hid_hiddev_list[] = {
1860         { HID_USB_DEVICE(USB_VENDOR_ID_MGE, USB_DEVICE_ID_MGE_UPS) },
1861         { HID_USB_DEVICE(USB_VENDOR_ID_MGE, USB_DEVICE_ID_MGE_UPS1) },
1862         { }
1863 };
1864 
1865 static bool hid_hiddev(struct hid_device *hdev)
1866 {
1867         return !!hid_match_id(hdev, hid_hiddev_list);
1868 }
1869 
1870 
1871 static ssize_t
1872 read_report_descriptor(struct file *filp, struct kobject *kobj,
1873                 struct bin_attribute *attr,
1874                 char *buf, loff_t off, size_t count)
1875 {
1876         struct device *dev = kobj_to_dev(kobj);
1877         struct hid_device *hdev = to_hid_device(dev);
1878 
1879         if (off >= hdev->rsize)
1880                 return 0;
1881 
1882         if (off + count > hdev->rsize)
1883                 count = hdev->rsize - off;
1884 
1885         memcpy(buf, hdev->rdesc + off, count);
1886 
1887         return count;
1888 }
1889 
1890 static ssize_t
1891 show_country(struct device *dev, struct device_attribute *attr,
1892                 char *buf)
1893 {
1894         struct hid_device *hdev = to_hid_device(dev);
1895 
1896         return sprintf(buf, "%02x\n", hdev->country & 0xff);
1897 }
1898 
1899 static struct bin_attribute dev_bin_attr_report_desc = {
1900         .attr = { .name = "report_descriptor", .mode = 0444 },
1901         .read = read_report_descriptor,
1902         .size = HID_MAX_DESCRIPTOR_SIZE,
1903 };
1904 
1905 static const struct device_attribute dev_attr_country = {
1906         .attr = { .name = "country", .mode = 0444 },
1907         .show = show_country,
1908 };
1909 
1910 int hid_connect(struct hid_device *hdev, unsigned int connect_mask)
1911 {
1912         static const char *types[] = { "Device", "Pointer", "Mouse", "Device",
1913                 "Joystick", "Gamepad", "Keyboard", "Keypad",
1914                 "Multi-Axis Controller"
1915         };
1916         const char *type, *bus;
1917         char buf[64] = "";
1918         unsigned int i;
1919         int len;
1920         int ret;
1921 
1922         if (hdev->quirks & HID_QUIRK_HIDDEV_FORCE)
1923                 connect_mask |= (HID_CONNECT_HIDDEV_FORCE | HID_CONNECT_HIDDEV);
1924         if (hdev->quirks & HID_QUIRK_HIDINPUT_FORCE)
1925                 connect_mask |= HID_CONNECT_HIDINPUT_FORCE;
1926         if (hdev->bus != BUS_USB)
1927                 connect_mask &= ~HID_CONNECT_HIDDEV;
1928         if (hid_hiddev(hdev))
1929                 connect_mask |= HID_CONNECT_HIDDEV_FORCE;
1930 
1931         if ((connect_mask & HID_CONNECT_HIDINPUT) && !hidinput_connect(hdev,
1932                                 connect_mask & HID_CONNECT_HIDINPUT_FORCE))
1933                 hdev->claimed |= HID_CLAIMED_INPUT;
1934 
1935         if ((connect_mask & HID_CONNECT_HIDDEV) && hdev->hiddev_connect &&
1936                         !hdev->hiddev_connect(hdev,
1937                                 connect_mask & HID_CONNECT_HIDDEV_FORCE))
1938                 hdev->claimed |= HID_CLAIMED_HIDDEV;
1939         if ((connect_mask & HID_CONNECT_HIDRAW) && !hidraw_connect(hdev))
1940                 hdev->claimed |= HID_CLAIMED_HIDRAW;
1941 
1942         if (connect_mask & HID_CONNECT_DRIVER)
1943                 hdev->claimed |= HID_CLAIMED_DRIVER;
1944 
1945         /* Drivers with the ->raw_event callback set are not required to connect
1946          * to any other listener. */
1947         if (!hdev->claimed && !hdev->driver->raw_event) {
1948                 hid_err(hdev, "device has no listeners, quitting\n");
1949                 return -ENODEV;
1950         }
1951 
1952         if ((hdev->claimed & HID_CLAIMED_INPUT) &&
1953                         (connect_mask & HID_CONNECT_FF) && hdev->ff_init)
1954                 hdev->ff_init(hdev);
1955 
1956         len = 0;
1957         if (hdev->claimed & HID_CLAIMED_INPUT)
1958                 len += sprintf(buf + len, "input");
1959         if (hdev->claimed & HID_CLAIMED_HIDDEV)
1960                 len += sprintf(buf + len, "%shiddev%d", len ? "," : "",
1961                                 ((struct hiddev *)hdev->hiddev)->minor);
1962         if (hdev->claimed & HID_CLAIMED_HIDRAW)
1963                 len += sprintf(buf + len, "%shidraw%d", len ? "," : "",
1964                                 ((struct hidraw *)hdev->hidraw)->minor);
1965 
1966         type = "Device";
1967         for (i = 0; i < hdev->maxcollection; i++) {
1968                 struct hid_collection *col = &hdev->collection[i];
1969                 if (col->type == HID_COLLECTION_APPLICATION &&
1970                    (col->usage & HID_USAGE_PAGE) == HID_UP_GENDESK &&
1971                    (col->usage & 0xffff) < ARRAY_SIZE(types)) {
1972                         type = types[col->usage & 0xffff];
1973                         break;
1974                 }
1975         }
1976 
1977         switch (hdev->bus) {
1978         case BUS_USB:
1979                 bus = "USB";
1980                 break;
1981         case BUS_BLUETOOTH:
1982                 bus = "BLUETOOTH";
1983                 break;
1984         case BUS_I2C:
1985                 bus = "I2C";
1986                 break;
1987         default:
1988                 bus = "<UNKNOWN>";
1989         }
1990 
1991         ret = device_create_file(&hdev->dev, &dev_attr_country);
1992         if (ret)
1993                 hid_warn(hdev,
1994                          "can't create sysfs country code attribute err: %d\n", ret);
1995 
1996         hid_info(hdev, "%s: %s HID v%x.%02x %s [%s] on %s\n",
1997                  buf, bus, hdev->version >> 8, hdev->version & 0xff,
1998                  type, hdev->name, hdev->phys);
1999 
2000         return 0;
2001 }
2002 EXPORT_SYMBOL_GPL(hid_connect);
2003 
2004 void hid_disconnect(struct hid_device *hdev)
2005 {
2006         device_remove_file(&hdev->dev, &dev_attr_country);
2007         if (hdev->claimed & HID_CLAIMED_INPUT)
2008                 hidinput_disconnect(hdev);
2009         if (hdev->claimed & HID_CLAIMED_HIDDEV)
2010                 hdev->hiddev_disconnect(hdev);
2011         if (hdev->claimed & HID_CLAIMED_HIDRAW)
2012                 hidraw_disconnect(hdev);
2013         hdev->claimed = 0;
2014 }
2015 EXPORT_SYMBOL_GPL(hid_disconnect);
2016 
2017 /**
2018  * hid_hw_start - start underlying HW
2019  * @hdev: hid device
2020  * @connect_mask: which outputs to connect, see HID_CONNECT_*
2021  *
2022  * Call this in probe function *after* hid_parse. This will setup HW
2023  * buffers and start the device (if not defeirred to device open).
2024  * hid_hw_stop must be called if this was successful.
2025  */
2026 int hid_hw_start(struct hid_device *hdev, unsigned int connect_mask)
2027 {
2028         int error;
2029 
2030         error = hdev->ll_driver->start(hdev);
2031         if (error)
2032                 return error;
2033 
2034         if (connect_mask) {
2035                 error = hid_connect(hdev, connect_mask);
2036                 if (error) {
2037                         hdev->ll_driver->stop(hdev);
2038                         return error;
2039                 }
2040         }
2041 
2042         return 0;
2043 }
2044 EXPORT_SYMBOL_GPL(hid_hw_start);
2045 
2046 /**
2047  * hid_hw_stop - stop underlying HW
2048  * @hdev: hid device
2049  *
2050  * This is usually called from remove function or from probe when something
2051  * failed and hid_hw_start was called already.
2052  */
2053 void hid_hw_stop(struct hid_device *hdev)
2054 {
2055         hid_disconnect(hdev);
2056         hdev->ll_driver->stop(hdev);
2057 }
2058 EXPORT_SYMBOL_GPL(hid_hw_stop);
2059 
2060 /**
2061  * hid_hw_open - signal underlying HW to start delivering events
2062  * @hdev: hid device
2063  *
2064  * Tell underlying HW to start delivering events from the device.
2065  * This function should be called sometime after successful call
2066  * to hid_hw_start().
2067  */
2068 int hid_hw_open(struct hid_device *hdev)
2069 {
2070         int ret;
2071 
2072         ret = mutex_lock_killable(&hdev->ll_open_lock);
2073         if (ret)
2074                 return ret;
2075 
2076         if (!hdev->ll_open_count++) {
2077                 ret = hdev->ll_driver->open(hdev);
2078                 if (ret)
2079                         hdev->ll_open_count--;
2080         }
2081 
2082         mutex_unlock(&hdev->ll_open_lock);
2083         return ret;
2084 }
2085 EXPORT_SYMBOL_GPL(hid_hw_open);
2086 
2087 /**
2088  * hid_hw_close - signal underlaying HW to stop delivering events
2089  *
2090  * @hdev: hid device
2091  *
2092  * This function indicates that we are not interested in the events
2093  * from this device anymore. Delivery of events may or may not stop,
2094  * depending on the number of users still outstanding.
2095  */
2096 void hid_hw_close(struct hid_device *hdev)
2097 {
2098         mutex_lock(&hdev->ll_open_lock);
2099         if (!--hdev->ll_open_count)
2100                 hdev->ll_driver->close(hdev);
2101         mutex_unlock(&hdev->ll_open_lock);
2102 }
2103 EXPORT_SYMBOL_GPL(hid_hw_close);
2104 
2105 struct hid_dynid {
2106         struct list_head list;
2107         struct hid_device_id id;
2108 };
2109 
2110 /**
2111  * store_new_id - add a new HID device ID to this driver and re-probe devices
2112  * @driver: target device driver
2113  * @buf: buffer for scanning device ID data
2114  * @count: input size
2115  *
2116  * Adds a new dynamic hid device ID to this driver,
2117  * and causes the driver to probe for all devices again.
2118  */
2119 static ssize_t new_id_store(struct device_driver *drv, const char *buf,
2120                 size_t count)
2121 {
2122         struct hid_driver *hdrv = to_hid_driver(drv);
2123         struct hid_dynid *dynid;
2124         __u32 bus, vendor, product;
2125         unsigned long driver_data = 0;
2126         int ret;
2127 
2128         ret = sscanf(buf, "%x %x %x %lx",
2129                         &bus, &vendor, &product, &driver_data);
2130         if (ret < 3)
2131                 return -EINVAL;
2132 
2133         dynid = kzalloc(sizeof(*dynid), GFP_KERNEL);
2134         if (!dynid)
2135                 return -ENOMEM;
2136 
2137         dynid->id.bus = bus;
2138         dynid->id.group = HID_GROUP_ANY;
2139         dynid->id.vendor = vendor;
2140         dynid->id.product = product;
2141         dynid->id.driver_data = driver_data;
2142 
2143         spin_lock(&hdrv->dyn_lock);
2144         list_add_tail(&dynid->list, &hdrv->dyn_list);
2145         spin_unlock(&hdrv->dyn_lock);
2146 
2147         ret = driver_attach(&hdrv->driver);
2148 
2149         return ret ? : count;
2150 }
2151 static DRIVER_ATTR_WO(new_id);
2152 
2153 static struct attribute *hid_drv_attrs[] = {
2154         &driver_attr_new_id.attr,
2155         NULL,
2156 };
2157 ATTRIBUTE_GROUPS(hid_drv);
2158 
2159 static void hid_free_dynids(struct hid_driver *hdrv)
2160 {
2161         struct hid_dynid *dynid, *n;
2162 
2163         spin_lock(&hdrv->dyn_lock);
2164         list_for_each_entry_safe(dynid, n, &hdrv->dyn_list, list) {
2165                 list_del(&dynid->list);
2166                 kfree(dynid);
2167         }
2168         spin_unlock(&hdrv->dyn_lock);
2169 }
2170 
2171 const struct hid_device_id *hid_match_device(struct hid_device *hdev,
2172                                              struct hid_driver *hdrv)
2173 {
2174         struct hid_dynid *dynid;
2175 
2176         spin_lock(&hdrv->dyn_lock);
2177         list_for_each_entry(dynid, &hdrv->dyn_list, list) {
2178                 if (hid_match_one_id(hdev, &dynid->id)) {
2179                         spin_unlock(&hdrv->dyn_lock);
2180                         return &dynid->id;
2181                 }
2182         }
2183         spin_unlock(&hdrv->dyn_lock);
2184 
2185         return hid_match_id(hdev, hdrv->id_table);
2186 }
2187 EXPORT_SYMBOL_GPL(hid_match_device);
2188 
2189 static int hid_bus_match(struct device *dev, struct device_driver *drv)
2190 {
2191         struct hid_driver *hdrv = to_hid_driver(drv);
2192         struct hid_device *hdev = to_hid_device(dev);
2193 
2194         return hid_match_device(hdev, hdrv) != NULL;
2195 }
2196 
2197 /**
2198  * hid_compare_device_paths - check if both devices share the same path
2199  * @hdev_a: hid device
2200  * @hdev_b: hid device
2201  * @separator: char to use as separator
2202  *
2203  * Check if two devices share the same path up to the last occurrence of
2204  * the separator char. Both paths must exist (i.e., zero-length paths
2205  * don't match).
2206  */
2207 bool hid_compare_device_paths(struct hid_device *hdev_a,
2208                               struct hid_device *hdev_b, char separator)
2209 {
2210         int n1 = strrchr(hdev_a->phys, separator) - hdev_a->phys;
2211         int n2 = strrchr(hdev_b->phys, separator) - hdev_b->phys;
2212 
2213         if (n1 != n2 || n1 <= 0 || n2 <= 0)
2214                 return false;
2215 
2216         return !strncmp(hdev_a->phys, hdev_b->phys, n1);
2217 }
2218 EXPORT_SYMBOL_GPL(hid_compare_device_paths);
2219 
2220 static int hid_device_probe(struct device *dev)
2221 {
2222         struct hid_driver *hdrv = to_hid_driver(dev->driver);
2223         struct hid_device *hdev = to_hid_device(dev);
2224         const struct hid_device_id *id;
2225         int ret = 0;
2226 
2227         if (down_interruptible(&hdev->driver_input_lock)) {
2228                 ret = -EINTR;
2229                 goto end;
2230         }
2231         hdev->io_started = false;
2232 
2233         clear_bit(ffs(HID_STAT_REPROBED), &hdev->status);
2234 
2235         if (!hdev->driver) {
2236                 id = hid_match_device(hdev, hdrv);
2237                 if (id == NULL) {
2238                         ret = -ENODEV;
2239                         goto unlock;
2240                 }
2241 
2242                 if (hdrv->match) {
2243                         if (!hdrv->match(hdev, hid_ignore_special_drivers)) {
2244                                 ret = -ENODEV;
2245                                 goto unlock;
2246                         }
2247                 } else {
2248                         /*
2249                          * hid-generic implements .match(), so if
2250                          * hid_ignore_special_drivers is set, we can safely
2251                          * return.
2252                          */
2253                         if (hid_ignore_special_drivers) {
2254                                 ret = -ENODEV;
2255                                 goto unlock;
2256                         }
2257                 }
2258 
2259                 /* reset the quirks that has been previously set */
2260                 hdev->quirks = hid_lookup_quirk(hdev);
2261                 hdev->driver = hdrv;
2262                 if (hdrv->probe) {
2263                         ret = hdrv->probe(hdev, id);
2264                 } else { /* default probe */
2265                         ret = hid_open_report(hdev);
2266                         if (!ret)
2267                                 ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
2268                 }
2269                 if (ret) {
2270                         hid_close_report(hdev);
2271                         hdev->driver = NULL;
2272                 }
2273         }
2274 unlock:
2275         if (!hdev->io_started)
2276                 up(&hdev->driver_input_lock);
2277 end:
2278         return ret;
2279 }
2280 
2281 static int hid_device_remove(struct device *dev)
2282 {
2283         struct hid_device *hdev = to_hid_device(dev);
2284         struct hid_driver *hdrv;
2285         int ret = 0;
2286 
2287         if (down_interruptible(&hdev->driver_input_lock)) {
2288                 ret = -EINTR;
2289                 goto end;
2290         }
2291         hdev->io_started = false;
2292 
2293         hdrv = hdev->driver;
2294         if (hdrv) {
2295                 if (hdrv->remove)
2296                         hdrv->remove(hdev);
2297                 else /* default remove */
2298                         hid_hw_stop(hdev);
2299                 hid_close_report(hdev);
2300                 hdev->driver = NULL;
2301         }
2302 
2303         if (!hdev->io_started)
2304                 up(&hdev->driver_input_lock);
2305 end:
2306         return ret;
2307 }
2308 
2309 static ssize_t modalias_show(struct device *dev, struct device_attribute *a,
2310                              char *buf)
2311 {
2312         struct hid_device *hdev = container_of(dev, struct hid_device, dev);
2313 
2314         return scnprintf(buf, PAGE_SIZE, "hid:b%04Xg%04Xv%08Xp%08X\n",
2315                          hdev->bus, hdev->group, hdev->vendor, hdev->product);
2316 }
2317 static DEVICE_ATTR_RO(modalias);
2318 
2319 static struct attribute *hid_dev_attrs[] = {
2320         &dev_attr_modalias.attr,
2321         NULL,
2322 };
2323 static struct bin_attribute *hid_dev_bin_attrs[] = {
2324         &dev_bin_attr_report_desc,
2325         NULL
2326 };
2327 static const struct attribute_group hid_dev_group = {
2328         .attrs = hid_dev_attrs,
2329         .bin_attrs = hid_dev_bin_attrs,
2330 };
2331 __ATTRIBUTE_GROUPS(hid_dev);
2332 
2333 static int hid_uevent(struct device *dev, struct kobj_uevent_env *env)
2334 {
2335         struct hid_device *hdev = to_hid_device(dev);
2336 
2337         if (add_uevent_var(env, "HID_ID=%04X:%08X:%08X",
2338                         hdev->bus, hdev->vendor, hdev->product))
2339                 return -ENOMEM;
2340 
2341         if (add_uevent_var(env, "HID_NAME=%s", hdev->name))
2342                 return -ENOMEM;
2343 
2344         if (add_uevent_var(env, "HID_PHYS=%s", hdev->phys))
2345                 return -ENOMEM;
2346 
2347         if (add_uevent_var(env, "HID_UNIQ=%s", hdev->uniq))
2348                 return -ENOMEM;
2349 
2350         if (add_uevent_var(env, "MODALIAS=hid:b%04Xg%04Xv%08Xp%08X",
2351                            hdev->bus, hdev->group, hdev->vendor, hdev->product))
2352                 return -ENOMEM;
2353 
2354         return 0;
2355 }
2356 
2357 struct bus_type hid_bus_type = {
2358         .name           = "hid",
2359         .dev_groups     = hid_dev_groups,
2360         .drv_groups     = hid_drv_groups,
2361         .match          = hid_bus_match,
2362         .probe          = hid_device_probe,
2363         .remove         = hid_device_remove,
2364         .uevent         = hid_uevent,
2365 };
2366 EXPORT_SYMBOL(hid_bus_type);
2367 
2368 int hid_add_device(struct hid_device *hdev)
2369 {
2370         static atomic_t id = ATOMIC_INIT(0);
2371         int ret;
2372 
2373         if (WARN_ON(hdev->status & HID_STAT_ADDED))
2374                 return -EBUSY;
2375 
2376         hdev->quirks = hid_lookup_quirk(hdev);
2377 
2378         /* we need to kill them here, otherwise they will stay allocated to
2379          * wait for coming driver */
2380         if (hid_ignore(hdev))
2381                 return -ENODEV;
2382 
2383         /*
2384          * Check for the mandatory transport channel.
2385          */
2386          if (!hdev->ll_driver->raw_request) {
2387                 hid_err(hdev, "transport driver missing .raw_request()\n");
2388                 return -EINVAL;
2389          }
2390 
2391         /*
2392          * Read the device report descriptor once and use as template
2393          * for the driver-specific modifications.
2394          */
2395         ret = hdev->ll_driver->parse(hdev);
2396         if (ret)
2397                 return ret;
2398         if (!hdev->dev_rdesc)
2399                 return -ENODEV;
2400 
2401         /*
2402          * Scan generic devices for group information
2403          */
2404         if (hid_ignore_special_drivers) {
2405                 hdev->group = HID_GROUP_GENERIC;
2406         } else if (!hdev->group &&
2407                    !(hdev->quirks & HID_QUIRK_HAVE_SPECIAL_DRIVER)) {
2408                 ret = hid_scan_report(hdev);
2409                 if (ret)
2410                         hid_warn(hdev, "bad device descriptor (%d)\n", ret);
2411         }
2412 
2413         /* XXX hack, any other cleaner solution after the driver core
2414          * is converted to allow more than 20 bytes as the device name? */
2415         dev_set_name(&hdev->dev, "%04X:%04X:%04X.%04X", hdev->bus,
2416                      hdev->vendor, hdev->product, atomic_inc_return(&id));
2417 
2418         hid_debug_register(hdev, dev_name(&hdev->dev));
2419         ret = device_add(&hdev->dev);
2420         if (!ret)
2421                 hdev->status |= HID_STAT_ADDED;
2422         else
2423                 hid_debug_unregister(hdev);
2424 
2425         return ret;
2426 }
2427 EXPORT_SYMBOL_GPL(hid_add_device);
2428 
2429 /**
2430  * hid_allocate_device - allocate new hid device descriptor
2431  *
2432  * Allocate and initialize hid device, so that hid_destroy_device might be
2433  * used to free it.
2434  *
2435  * New hid_device pointer is returned on success, otherwise ERR_PTR encoded
2436  * error value.
2437  */
2438 struct hid_device *hid_allocate_device(void)
2439 {
2440         struct hid_device *hdev;
2441         int ret = -ENOMEM;
2442 
2443         hdev = kzalloc(sizeof(*hdev), GFP_KERNEL);
2444         if (hdev == NULL)
2445                 return ERR_PTR(ret);
2446 
2447         device_initialize(&hdev->dev);
2448         hdev->dev.release = hid_device_release;
2449         hdev->dev.bus = &hid_bus_type;
2450         device_enable_async_suspend(&hdev->dev);
2451 
2452         hid_close_report(hdev);
2453 
2454         init_waitqueue_head(&hdev->debug_wait);
2455         INIT_LIST_HEAD(&hdev->debug_list);
2456         spin_lock_init(&hdev->debug_list_lock);
2457         sema_init(&hdev->driver_input_lock, 1);
2458         mutex_init(&hdev->ll_open_lock);
2459 
2460         return hdev;
2461 }
2462 EXPORT_SYMBOL_GPL(hid_allocate_device);
2463 
2464 static void hid_remove_device(struct hid_device *hdev)
2465 {
2466         if (hdev->status & HID_STAT_ADDED) {
2467                 device_del(&hdev->dev);
2468                 hid_debug_unregister(hdev);
2469                 hdev->status &= ~HID_STAT_ADDED;
2470         }
2471         kfree(hdev->dev_rdesc);
2472         hdev->dev_rdesc = NULL;
2473         hdev->dev_rsize = 0;
2474 }
2475 
2476 /**
2477  * hid_destroy_device - free previously allocated device
2478  *
2479  * @hdev: hid device
2480  *
2481  * If you allocate hid_device through hid_allocate_device, you should ever
2482  * free by this function.
2483  */
2484 void hid_destroy_device(struct hid_device *hdev)
2485 {
2486         hid_remove_device(hdev);
2487         put_device(&hdev->dev);
2488 }
2489 EXPORT_SYMBOL_GPL(hid_destroy_device);
2490 
2491 
2492 static int __hid_bus_reprobe_drivers(struct device *dev, void *data)
2493 {
2494         struct hid_driver *hdrv = data;
2495         struct hid_device *hdev = to_hid_device(dev);
2496 
2497         if (hdev->driver == hdrv &&
2498             !hdrv->match(hdev, hid_ignore_special_drivers) &&
2499             !test_and_set_bit(ffs(HID_STAT_REPROBED), &hdev->status))
2500                 return device_reprobe(dev);
2501 
2502         return 0;
2503 }
2504 
2505 static int __hid_bus_driver_added(struct device_driver *drv, void *data)
2506 {
2507         struct hid_driver *hdrv = to_hid_driver(drv);
2508 
2509         if (hdrv->match) {
2510                 bus_for_each_dev(&hid_bus_type, NULL, hdrv,
2511                                  __hid_bus_reprobe_drivers);
2512         }
2513 
2514         return 0;
2515 }
2516 
2517 static int __bus_removed_driver(struct device_driver *drv, void *data)
2518 {
2519         return bus_rescan_devices(&hid_bus_type);
2520 }
2521 
2522 int __hid_register_driver(struct hid_driver *hdrv, struct module *owner,
2523                 const char *mod_name)
2524 {
2525         int ret;
2526 
2527         hdrv->driver.name = hdrv->name;
2528         hdrv->driver.bus = &hid_bus_type;
2529         hdrv->driver.owner = owner;
2530         hdrv->driver.mod_name = mod_name;
2531 
2532         INIT_LIST_HEAD(&hdrv->dyn_list);
2533         spin_lock_init(&hdrv->dyn_lock);
2534 
2535         ret = driver_register(&hdrv->driver);
2536 
2537         if (ret == 0)
2538                 bus_for_each_drv(&hid_bus_type, NULL, NULL,
2539                                  __hid_bus_driver_added);
2540 
2541         return ret;
2542 }
2543 EXPORT_SYMBOL_GPL(__hid_register_driver);
2544 
2545 void hid_unregister_driver(struct hid_driver *hdrv)
2546 {
2547         driver_unregister(&hdrv->driver);
2548         hid_free_dynids(hdrv);
2549 
2550         bus_for_each_drv(&hid_bus_type, NULL, hdrv, __bus_removed_driver);
2551 }
2552 EXPORT_SYMBOL_GPL(hid_unregister_driver);
2553 
2554 int hid_check_keys_pressed(struct hid_device *hid)
2555 {
2556         struct hid_input *hidinput;
2557         int i;
2558 
2559         if (!(hid->claimed & HID_CLAIMED_INPUT))
2560                 return 0;
2561 
2562         list_for_each_entry(hidinput, &hid->inputs, list) {
2563                 for (i = 0; i < BITS_TO_LONGS(KEY_MAX); i++)
2564                         if (hidinput->input->key[i])
2565                                 return 1;
2566         }
2567 
2568         return 0;
2569 }
2570 
2571 EXPORT_SYMBOL_GPL(hid_check_keys_pressed);
2572 
2573 static int __init hid_init(void)
2574 {
2575         int ret;
2576 
2577         if (hid_debug)
2578                 pr_warn("hid_debug is now used solely for parser and driver debugging.\n"
2579                         "debugfs is now used for inspecting the device (report descriptor, reports)\n");
2580 
2581         ret = bus_register(&hid_bus_type);
2582         if (ret) {
2583                 pr_err("can't register hid bus\n");
2584                 goto err;
2585         }
2586 
2587         ret = hidraw_init();
2588         if (ret)
2589                 goto err_bus;
2590 
2591         hid_debug_init();
2592 
2593         return 0;
2594 err_bus:
2595         bus_unregister(&hid_bus_type);
2596 err:
2597         return ret;
2598 }
2599 
2600 static void __exit hid_exit(void)
2601 {
2602         hid_debug_exit();
2603         hidraw_exit();
2604         bus_unregister(&hid_bus_type);
2605         hid_quirks_exit(HID_BUS_ANY);
2606 }
2607 
2608 module_init(hid_init);
2609 module_exit(hid_exit);
2610 
2611 MODULE_AUTHOR("Andreas Gal");
2612 MODULE_AUTHOR("Vojtech Pavlik");
2613 MODULE_AUTHOR("Jiri Kosina");
2614 MODULE_LICENSE("GPL");