drivers/hid/hid-core.c

   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)
  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                          usages * 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);
 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         if ((parser->global.usage_page << 16) == HID_UP_GOOGLEVENDOR)
 819                 for (i = 0; i < parser->local.usage_index; i++)
 820                         if (parser->local.usage[i] ==
 821                                         (HID_UP_GOOGLEVENDOR | 0x0001))
 822                                 parser->device->group =
 823                                         HID_GROUP_VIVALDI;
 824 }
 825
 826 static int hid_scan_main(struct hid_parser *parser, struct hid_item *item)
 827 {
 828         __u32 data;
 829         int i;
 830
 831         hid_concatenate_last_usage_page(parser);
 832
 833         data = item_udata(item);
 834
 835         switch (item->tag) {
 836         case HID_MAIN_ITEM_TAG_BEGIN_COLLECTION:
 837                 hid_scan_collection(parser, data & 0xff);
 838                 break;
 839         case HID_MAIN_ITEM_TAG_END_COLLECTION:
 840                 break;
 841         case HID_MAIN_ITEM_TAG_INPUT:
 842                 /* ignore constant inputs, they will be ignored by hid-input */
 843                 if (data & HID_MAIN_ITEM_CONSTANT)
 844                         break;
 845                 for (i = 0; i < parser->local.usage_index; i++)
 846                         hid_scan_input_usage(parser, parser->local.usage[i]);
 847                 break;
 848         case HID_MAIN_ITEM_TAG_OUTPUT:
 849                 break;
 850         case HID_MAIN_ITEM_TAG_FEATURE:
 851                 for (i = 0; i < parser->local.usage_index; i++)
 852                         hid_scan_feature_usage(parser, parser->local.usage[i]);
 853                 break;
 854         }
 855
 856         /* Reset the local parser environment */
 857         memset(&parser->local, 0, sizeof(parser->local));
 858
 859         return 0;
 860 }
 861
 862 /*
 863  * Scan a report descriptor before the device is added to the bus.
 864  * Sets device groups and other properties that determine what driver
 865  * to load.
 866  */
 867 static int hid_scan_report(struct hid_device *hid)
 868 {
 869         struct hid_parser *parser;
 870         struct hid_item item;
 871         __u8 *start = hid->dev_rdesc;
 872         __u8 *end = start + hid->dev_rsize;
 873         static int (*dispatch_type[])(struct hid_parser *parser,
 874                                       struct hid_item *item) = {
 875                 hid_scan_main,
 876                 hid_parser_global,
 877                 hid_parser_local,
 878                 hid_parser_reserved
 879         };
 880
 881         parser = vzalloc(sizeof(struct hid_parser));
 882         if (!parser)
 883                 return -ENOMEM;
 884
 885         parser->device = hid;
 886         hid->group = HID_GROUP_GENERIC;
 887
 888         /*
 889          * The parsing is simpler than the one in hid_open_report() as we should
 890          * be robust against hid errors. Those errors will be raised by
 891          * hid_open_report() anyway.
 892          */
 893         while ((start = fetch_item(start, end, &item)) != NULL)
 894                 dispatch_type[item.type](parser, &item);
 895
 896         /*
 897          * Handle special flags set during scanning.
 898          */
 899         if ((parser->scan_flags & HID_SCAN_FLAG_MT_WIN_8) &&
 900             (hid->group == HID_GROUP_MULTITOUCH))
 901                 hid->group = HID_GROUP_MULTITOUCH_WIN_8;
 902
 903         /*
 904          * Vendor specific handlings
 905          */
 906         switch (hid->vendor) {
 907         case USB_VENDOR_ID_WACOM:
 908                 hid->group = HID_GROUP_WACOM;
 909                 break;
 910         case USB_VENDOR_ID_SYNAPTICS:
 911                 if (hid->group == HID_GROUP_GENERIC)
 912                         if ((parser->scan_flags & HID_SCAN_FLAG_VENDOR_SPECIFIC)
 913                             && (parser->scan_flags & HID_SCAN_FLAG_GD_POINTER))
 914                                 /*
 915                                  * hid-rmi should take care of them,
 916                                  * not hid-generic
 917                                  */
 918                                 hid->group = HID_GROUP_RMI;
 919                 break;
 920         }
 921
 922         kfree(parser->collection_stack);
 923         vfree(parser);
 924         return 0;
 925 }
 926
 927 /**
 928  * hid_parse_report - parse device report
 929  *
 930  * @hid: hid device
 931  * @start: report start
 932  * @size: report size
 933  *
 934  * Allocate the device report as read by the bus driver. This function should
 935  * only be called from parse() in ll drivers.
 936  */
 937 int hid_parse_report(struct hid_device *hid, __u8 *start, unsigned size)
 938 {
 939         hid->dev_rdesc = kmemdup(start, size, GFP_KERNEL);
 940         if (!hid->dev_rdesc)
 941                 return -ENOMEM;
 942         hid->dev_rsize = size;
 943         return 0;
 944 }
 945 EXPORT_SYMBOL_GPL(hid_parse_report);
 946
 947 static const char * const hid_report_names[] = {
 948         "HID_INPUT_REPORT",
 949         "HID_OUTPUT_REPORT",
 950         "HID_FEATURE_REPORT",
 951 };
 952 /**
 953  * hid_validate_values - validate existing device report's value indexes
 954  *
 955  * @hid: hid device
 956  * @type: which report type to examine
 957  * @id: which report ID to examine (0 for first)
 958  * @field_index: which report field to examine
 959  * @report_counts: expected number of values
 960  *
 961  * Validate the number of values in a given field of a given report, after
 962  * parsing.
 963  */
 964 struct hid_report *hid_validate_values(struct hid_device *hid,
 965                                        unsigned int type, unsigned int id,
 966                                        unsigned int field_index,
 967                                        unsigned int report_counts)
 968 {
 969         struct hid_report *report;
 970
 971         if (type > HID_FEATURE_REPORT) {
 972                 hid_err(hid, "invalid HID report type %u\n", type);
 973                 return NULL;
 974         }
 975
 976         if (id >= HID_MAX_IDS) {
 977                 hid_err(hid, "invalid HID report id %u\n", id);
 978                 return NULL;
 979         }
 980
 981         /*
 982          * Explicitly not using hid_get_report() here since it depends on
 983          * ->numbered being checked, which may not always be the case when
 984          * drivers go to access report values.
 985          */
 986         if (id == 0) {
 987                 /*
 988                  * Validating on id 0 means we should examine the first
 989                  * report in the list.
 990                  */
 991                 report = list_entry(
 992                                 hid->report_enum[type].report_list.next,
 993                                 struct hid_report, list);
 994         } else {
 995                 report = hid->report_enum[type].report_id_hash[id];
 996         }
 997         if (!report) {
 998                 hid_err(hid, "missing %s %u\n", hid_report_names[type], id);
 999                 return NULL;
1000         }
1001         if (report->maxfield <= field_index) {
1002                 hid_err(hid, "not enough fields in %s %u\n",
1003                         hid_report_names[type], id);
1004                 return NULL;
1005         }
1006         if (report->field[field_index]->report_count < report_counts) {
1007                 hid_err(hid, "not enough values in %s %u field %u\n",
1008                         hid_report_names[type], id, field_index);
1009                 return NULL;
1010         }
1011         return report;
1012 }
1013 EXPORT_SYMBOL_GPL(hid_validate_values);
1014
1015 static int hid_calculate_multiplier(struct hid_device *hid,
1016                                      struct hid_field *multiplier)
1017 {
1018         int m;
1019         __s32 v = *multiplier->value;
1020         __s32 lmin = multiplier->logical_minimum;
1021         __s32 lmax = multiplier->logical_maximum;
1022         __s32 pmin = multiplier->physical_minimum;
1023         __s32 pmax = multiplier->physical_maximum;
1024
1025         /*
1026          * "Because OS implementations will generally divide the control's
1027          * reported count by the Effective Resolution Multiplier, designers
1028          * should take care not to establish a potential Effective
1029          * Resolution Multiplier of zero."
1030          * HID Usage Table, v1.12, Section 4.3.1, p31
1031          */
1032         if (lmax - lmin == 0)
1033                 return 1;
1034         /*
1035          * Handling the unit exponent is left as an exercise to whoever
1036          * finds a device where that exponent is not 0.
1037          */
1038         m = ((v - lmin)/(lmax - lmin) * (pmax - pmin) + pmin);
1039         if (unlikely(multiplier->unit_exponent != 0)) {
1040                 hid_warn(hid,
1041                          "unsupported Resolution Multiplier unit exponent %d\n",
1042                          multiplier->unit_exponent);
1043         }
1044
1045         /* There are no devices with an effective multiplier > 255 */
1046         if (unlikely(m == 0 || m > 255 || m < -255)) {
1047                 hid_warn(hid, "unsupported Resolution Multiplier %d\n", m);
1048                 m = 1;
1049         }
1050
1051         return m;
1052 }
1053
1054 static void hid_apply_multiplier_to_field(struct hid_device *hid,
1055                                           struct hid_field *field,
1056                                           struct hid_collection *multiplier_collection,
1057                                           int effective_multiplier)
1058 {
1059         struct hid_collection *collection;
1060         struct hid_usage *usage;
1061         int i;
1062
1063         /*
1064          * If multiplier_collection is NULL, the multiplier applies
1065          * to all fields in the report.
1066          * Otherwise, it is the Logical Collection the multiplier applies to
1067          * but our field may be in a subcollection of that collection.
1068          */
1069         for (i = 0; i < field->maxusage; i++) {
1070                 usage = &field->usage[i];
1071
1072                 collection = &hid->collection[usage->collection_index];
1073                 while (collection->parent_idx != -1 &&
1074                        collection != multiplier_collection)
1075                         collection = &hid->collection[collection->parent_idx];
1076
1077                 if (collection->parent_idx != -1 ||
1078                     multiplier_collection == NULL)
1079                         usage->resolution_multiplier = effective_multiplier;
1080
1081         }
1082 }
1083
1084 static void hid_apply_multiplier(struct hid_device *hid,
1085                                  struct hid_field *multiplier)
1086 {
1087         struct hid_report_enum *rep_enum;
1088         struct hid_report *rep;
1089         struct hid_field *field;
1090         struct hid_collection *multiplier_collection;
1091         int effective_multiplier;
1092         int i;
1093
1094         /*
1095          * "The Resolution Multiplier control must be contained in the same
1096          * Logical Collection as the control(s) to which it is to be applied.
1097          * If no Resolution Multiplier is defined, then the Resolution
1098          * Multiplier defaults to 1.  If more than one control exists in a
1099          * Logical Collection, the Resolution Multiplier is associated with
1100          * all controls in the collection. If no Logical Collection is
1101          * defined, the Resolution Multiplier is associated with all
1102          * controls in the report."
1103          * HID Usage Table, v1.12, Section 4.3.1, p30
1104          *
1105          * Thus, search from the current collection upwards until we find a
1106          * logical collection. Then search all fields for that same parent
1107          * collection. Those are the fields the multiplier applies to.
1108          *
1109          * If we have more than one multiplier, it will overwrite the
1110          * applicable fields later.
1111          */
1112         multiplier_collection = &hid->collection[multiplier->usage->collection_index];
1113         while (multiplier_collection->parent_idx != -1 &&
1114                multiplier_collection->type != HID_COLLECTION_LOGICAL)
1115                 multiplier_collection = &hid->collection[multiplier_collection->parent_idx];
1116
1117         effective_multiplier = hid_calculate_multiplier(hid, multiplier);
1118
1119         rep_enum = &hid->report_enum[HID_INPUT_REPORT];
1120         list_for_each_entry(rep, &rep_enum->report_list, list) {
1121                 for (i = 0; i < rep->maxfield; i++) {
1122                         field = rep->field[i];
1123                         hid_apply_multiplier_to_field(hid, field,
1124                                                       multiplier_collection,
1125                                                       effective_multiplier);
1126                 }
1127         }
1128 }
1129
1130 /*
1131  * hid_setup_resolution_multiplier - set up all resolution multipliers
1132  *
1133  * @device: hid device
1134  *
1135  * Search for all Resolution Multiplier Feature Reports and apply their
1136  * value to all matching Input items. This only updates the internal struct
1137  * fields.
1138  *
1139  * The Resolution Multiplier is applied by the hardware. If the multiplier
1140  * is anything other than 1, the hardware will send pre-multiplied events
1141  * so that the same physical interaction generates an accumulated
1142  *      accumulated_value = value * * multiplier
1143  * This may be achieved by sending
1144  * - "value * multiplier" for each event, or
1145  * - "value" but "multiplier" times as frequently, or
1146  * - a combination of the above
1147  * The only guarantee is that the same physical interaction always generates
1148  * an accumulated 'value * multiplier'.
1149  *
1150  * This function must be called before any event processing and after
1151  * any SetRequest to the Resolution Multiplier.
1152  */
1153 void hid_setup_resolution_multiplier(struct hid_device *hid)
1154 {
1155         struct hid_report_enum *rep_enum;
1156         struct hid_report *rep;
1157         struct hid_usage *usage;
1158         int i, j;
1159
1160         rep_enum = &hid->report_enum[HID_FEATURE_REPORT];
1161         list_for_each_entry(rep, &rep_enum->report_list, list) {
1162                 for (i = 0; i < rep->maxfield; i++) {
1163                         /* Ignore if report count is out of bounds. */
1164                         if (rep->field[i]->report_count < 1)
1165                                 continue;
1166
1167                         for (j = 0; j < rep->field[i]->maxusage; j++) {
1168                                 usage = &rep->field[i]->usage[j];
1169                                 if (usage->hid == HID_GD_RESOLUTION_MULTIPLIER)
1170                                         hid_apply_multiplier(hid,
1171                                                              rep->field[i]);
1172                         }
1173                 }
1174         }
1175 }
1176 EXPORT_SYMBOL_GPL(hid_setup_resolution_multiplier);
1177
1178 /**
1179  * hid_open_report - open a driver-specific device report
1180  *
1181  * @device: hid device
1182  *
1183  * Parse a report description into a hid_device structure. Reports are
1184  * enumerated, fields are attached to these reports.
1185  * 0 returned on success, otherwise nonzero error value.
1186  *
1187  * This function (or the equivalent hid_parse() macro) should only be
1188  * called from probe() in drivers, before starting the device.
1189  */
1190 int hid_open_report(struct hid_device *device)
1191 {
1192         struct hid_parser *parser;
1193         struct hid_item item;
1194         unsigned int size;
1195         __u8 *start;
1196         __u8 *buf;
1197         __u8 *end;
1198         __u8 *next;
1199         int ret;
1200         static int (*dispatch_type[])(struct hid_parser *parser,
1201                                       struct hid_item *item) = {
1202                 hid_parser_main,
1203                 hid_parser_global,
1204                 hid_parser_local,
1205                 hid_parser_reserved
1206         };
1207
1208         if (WARN_ON(device->status & HID_STAT_PARSED))
1209                 return -EBUSY;
1210
1211         start = device->dev_rdesc;
1212         if (WARN_ON(!start))
1213                 return -ENODEV;
1214         size = device->dev_rsize;
1215
1216         buf = kmemdup(start, size, GFP_KERNEL);
1217         if (buf == NULL)
1218                 return -ENOMEM;
1219
1220         if (device->driver->report_fixup)
1221                 start = device->driver->report_fixup(device, buf, &size);
1222         else
1223                 start = buf;
1224
1225         start = kmemdup(start, size, GFP_KERNEL);
1226         kfree(buf);
1227         if (start == NULL)
1228                 return -ENOMEM;
1229
1230         device->rdesc = start;
1231         device->rsize = size;
1232
1233         parser = vzalloc(sizeof(struct hid_parser));
1234         if (!parser) {
1235                 ret = -ENOMEM;
1236                 goto alloc_err;
1237         }
1238
1239         parser->device = device;
1240
1241         end = start + size;
1242
1243         device->collection = kcalloc(HID_DEFAULT_NUM_COLLECTIONS,
1244                                      sizeof(struct hid_collection), GFP_KERNEL);
1245         if (!device->collection) {
1246                 ret = -ENOMEM;
1247                 goto err;
1248         }
1249         device->collection_size = HID_DEFAULT_NUM_COLLECTIONS;
1250
1251         ret = -EINVAL;
1252         while ((next = fetch_item(start, end, &item)) != NULL) {
1253                 start = next;
1254
1255                 if (item.format != HID_ITEM_FORMAT_SHORT) {
1256                         hid_err(device, "unexpected long global item\n");
1257                         goto err;
1258                 }
1259
1260                 if (dispatch_type[item.type](parser, &item)) {
1261                         hid_err(device, "item %u %u %u %u parsing failed\n",
1262                                 item.format, (unsigned)item.size,
1263                                 (unsigned)item.type, (unsigned)item.tag);
1264                         goto err;
1265                 }
1266
1267                 if (start == end) {
1268                         if (parser->collection_stack_ptr) {
1269                                 hid_err(device, "unbalanced collection at end of report description\n");
1270                                 goto err;
1271                         }
1272                         if (parser->local.delimiter_depth) {
1273                                 hid_err(device, "unbalanced delimiter at end of report description\n");
1274                                 goto err;
1275                         }
1276
1277                         /*
1278                          * fetch initial values in case the device's
1279                          * default multiplier isn't the recommended 1
1280                          */
1281                         hid_setup_resolution_multiplier(device);
1282
1283                         kfree(parser->collection_stack);
1284                         vfree(parser);
1285                         device->status |= HID_STAT_PARSED;
1286
1287                         return 0;
1288                 }
1289         }
1290
1291         hid_err(device, "item fetching failed at offset %u/%u\n",
1292                 size - (unsigned int)(end - start), size);
1293 err:
1294         kfree(parser->collection_stack);
1295 alloc_err:
1296         vfree(parser);
1297         hid_close_report(device);
1298         return ret;
1299 }
1300 EXPORT_SYMBOL_GPL(hid_open_report);
1301
1302 /*
1303  * Convert a signed n-bit integer to signed 32-bit integer. Common
1304  * cases are done through the compiler, the screwed things has to be
1305  * done by hand.
1306  */
1307
1308 static s32 snto32(__u32 value, unsigned n)
1309 {
1310         if (!value || !n)
1311                 return 0;
1312
1313         switch (n) {
1314         case 8:  return ((__s8)value);
1315         case 16: return ((__s16)value);
1316         case 32: return ((__s32)value);
1317         }
1318         return value & (1 << (n - 1)) ? value | (~0U << n) : value;
1319 }
1320
1321 s32 hid_snto32(__u32 value, unsigned n)
1322 {
1323         return snto32(value, n);
1324 }
1325 EXPORT_SYMBOL_GPL(hid_snto32);
1326
1327 /*
1328  * Convert a signed 32-bit integer to a signed n-bit integer.
1329  */
1330
1331 static u32 s32ton(__s32 value, unsigned n)
1332 {
1333         s32 a = value >> (n - 1);
1334         if (a && a != -1)
1335                 return value < 0 ? 1 << (n - 1) : (1 << (n - 1)) - 1;
1336         return value & ((1 << n) - 1);
1337 }
1338
1339 /*
1340  * Extract/implement a data field from/to a little endian report (bit array).
1341  *
1342  * Code sort-of follows HID spec:
1343  *     http://www.usb.org/developers/hidpage/HID1_11.pdf
1344  *
1345  * While the USB HID spec allows unlimited length bit fields in "report
1346  * descriptors", most devices never use more than 16 bits.
1347  * One model of UPS is claimed to report "LINEV" as a 32-bit field.
1348  * Search linux-kernel and linux-usb-devel archives for "hid-core extract".
1349  */
1350
1351 static u32 __extract(u8 *report, unsigned offset, int n)
1352 {
1353         unsigned int idx = offset / 8;
1354         unsigned int bit_nr = 0;
1355         unsigned int bit_shift = offset % 8;
1356         int bits_to_copy = 8 - bit_shift;
1357         u32 value = 0;
1358         u32 mask = n < 32 ? (1U << n) - 1 : ~0U;
1359
1360         while (n > 0) {
1361                 value |= ((u32)report[idx] >> bit_shift) << bit_nr;
1362                 n -= bits_to_copy;
1363                 bit_nr += bits_to_copy;
1364                 bits_to_copy = 8;
1365                 bit_shift = 0;
1366                 idx++;
1367         }
1368
1369         return value & mask;
1370 }
1371
1372 u32 hid_field_extract(const struct hid_device *hid, u8 *report,
1373                         unsigned offset, unsigned n)
1374 {
1375         if (n > 32) {
1376                 hid_warn_once(hid, "%s() called with n (%d) > 32! (%s)\n",
1377                               __func__, n, current->comm);
1378                 n = 32;
1379         }
1380
1381         return __extract(report, offset, n);
1382 }
1383 EXPORT_SYMBOL_GPL(hid_field_extract);
1384
1385 /*
1386  * "implement" : set bits in a little endian bit stream.
1387  * Same concepts as "extract" (see comments above).
1388  * The data mangled in the bit stream remains in little endian
1389  * order the whole time. It make more sense to talk about
1390  * endianness of register values by considering a register
1391  * a "cached" copy of the little endian bit stream.
1392  */
1393
1394 static void __implement(u8 *report, unsigned offset, int n, u32 value)
1395 {
1396         unsigned int idx = offset / 8;
1397         unsigned int bit_shift = offset % 8;
1398         int bits_to_set = 8 - bit_shift;
1399
1400         while (n - bits_to_set >= 0) {
1401                 report[idx] &= ~(0xff << bit_shift);
1402                 report[idx] |= value << bit_shift;
1403                 value >>= bits_to_set;
1404                 n -= bits_to_set;
1405                 bits_to_set = 8;
1406                 bit_shift = 0;
1407                 idx++;
1408         }
1409
1410         /* last nibble */
1411         if (n) {
1412                 u8 bit_mask = ((1U << n) - 1);
1413                 report[idx] &= ~(bit_mask << bit_shift);
1414                 report[idx] |= value << bit_shift;
1415         }
1416 }
1417
1418 static void implement(const struct hid_device *hid, u8 *report,
1419                       unsigned offset, unsigned n, u32 value)
1420 {
1421         if (unlikely(n > 32)) {
1422                 hid_warn(hid, "%s() called with n (%d) > 32! (%s)\n",
1423                          __func__, n, current->comm);
1424                 n = 32;
1425         } else if (n < 32) {
1426                 u32 m = (1U << n) - 1;
1427
1428                 if (unlikely(value > m)) {
1429                         hid_warn(hid,
1430                                  "%s() called with too large value %d (n: %d)! (%s)\n",
1431                                  __func__, value, n, current->comm);
1432                         WARN_ON(1);
1433                         value &= m;
1434                 }
1435         }
1436
1437         __implement(report, offset, n, value);
1438 }
1439
1440 /*
1441  * Search an array for a value.
1442  */
1443
1444 static int search(__s32 *array, __s32 value, unsigned n)
1445 {
1446         while (n--) {
1447                 if (*array++ == value)
1448                         return 0;
1449         }
1450         return -1;
1451 }
1452
1453 /**
1454  * hid_match_report - check if driver's raw_event should be called
1455  *
1456  * @hid: hid device
1457  * @report: hid report to match against
1458  *
1459  * compare hid->driver->report_table->report_type to report->type
1460  */
1461 static int hid_match_report(struct hid_device *hid, struct hid_report *report)
1462 {
1463         const struct hid_report_id *id = hid->driver->report_table;
1464
1465         if (!id) /* NULL means all */
1466                 return 1;
1467
1468         for (; id->report_type != HID_TERMINATOR; id++)
1469                 if (id->report_type == HID_ANY_ID ||
1470                                 id->report_type == report->type)
1471                         return 1;
1472         return 0;
1473 }
1474
1475 /**
1476  * hid_match_usage - check if driver's event should be called
1477  *
1478  * @hid: hid device
1479  * @usage: usage to match against
1480  *
1481  * compare hid->driver->usage_table->usage_{type,code} to
1482  * usage->usage_{type,code}
1483  */
1484 static int hid_match_usage(struct hid_device *hid, struct hid_usage *usage)
1485 {
1486         const struct hid_usage_id *id = hid->driver->usage_table;
1487
1488         if (!id) /* NULL means all */
1489                 return 1;
1490
1491         for (; id->usage_type != HID_ANY_ID - 1; id++)
1492                 if ((id->usage_hid == HID_ANY_ID ||
1493                                 id->usage_hid == usage->hid) &&
1494                                 (id->usage_type == HID_ANY_ID ||
1495                                 id->usage_type == usage->type) &&
1496                                 (id->usage_code == HID_ANY_ID ||
1497                                  id->usage_code == usage->code))
1498                         return 1;
1499         return 0;
1500 }
1501
1502 static void hid_process_event(struct hid_device *hid, struct hid_field *field,
1503                 struct hid_usage *usage, __s32 value, int interrupt)
1504 {
1505         struct hid_driver *hdrv = hid->driver;
1506         int ret;
1507
1508         if (!list_empty(&hid->debug_list))
1509                 hid_dump_input(hid, usage, value);
1510
1511         if (hdrv && hdrv->event && hid_match_usage(hid, usage)) {
1512                 ret = hdrv->event(hid, field, usage, value);
1513                 if (ret != 0) {
1514                         if (ret < 0)
1515                                 hid_err(hid, "%s's event failed with %d\n",
1516                                                 hdrv->name, ret);
1517                         return;
1518                 }
1519         }
1520
1521         if (hid->claimed & HID_CLAIMED_INPUT)
1522                 hidinput_hid_event(hid, field, usage, value);
1523         if (hid->claimed & HID_CLAIMED_HIDDEV && interrupt && hid->hiddev_hid_event)
1524                 hid->hiddev_hid_event(hid, field, usage, value);
1525 }
1526
1527 /*
1528  * Analyse a received field, and fetch the data from it. The field
1529  * content is stored for next report processing (we do differential
1530  * reporting to the layer).
1531  */
1532
1533 static void hid_input_field(struct hid_device *hid, struct hid_field *field,
1534                             __u8 *data, int interrupt)
1535 {
1536         unsigned n;
1537         unsigned count = field->report_count;
1538         unsigned offset = field->report_offset;
1539         unsigned size = field->report_size;
1540         __s32 min = field->logical_minimum;
1541         __s32 max = field->logical_maximum;
1542         __s32 *value;
1543
1544         value = kmalloc_array(count, sizeof(__s32), GFP_ATOMIC);
1545         if (!value)
1546                 return;
1547
1548         for (n = 0; n < count; n++) {
1549
1550                 value[n] = min < 0 ?
1551                         snto32(hid_field_extract(hid, data, offset + n * size,
1552                                size), size) :
1553                         hid_field_extract(hid, data, offset + n * size, size);
1554
1555                 /* Ignore report if ErrorRollOver */
1556                 if (!(field->flags & HID_MAIN_ITEM_VARIABLE) &&
1557                     value[n] >= min && value[n] <= max &&
1558                     value[n] - min < field->maxusage &&
1559                     field->usage[value[n] - min].hid == HID_UP_KEYBOARD + 1)
1560                         goto exit;
1561         }
1562
1563         for (n = 0; n < count; n++) {
1564
1565                 if (HID_MAIN_ITEM_VARIABLE & field->flags) {
1566                         hid_process_event(hid, field, &field->usage[n], value[n], interrupt);
1567                         continue;
1568                 }
1569
1570                 if (field->value[n] >= min && field->value[n] <= max
1571                         && field->value[n] - min < field->maxusage
1572                         && field->usage[field->value[n] - min].hid
1573                         && search(value, field->value[n], count))
1574                                 hid_process_event(hid, field, &field->usage[field->value[n] - min], 0, interrupt);
1575
1576                 if (value[n] >= min && value[n] <= max
1577                         && value[n] - min < field->maxusage
1578                         && field->usage[value[n] - min].hid
1579                         && search(field->value, value[n], count))
1580                                 hid_process_event(hid, field, &field->usage[value[n] - min], 1, interrupt);
1581         }
1582
1583         memcpy(field->value, value, count * sizeof(__s32));
1584 exit:
1585         kfree(value);
1586 }
1587
1588 /*
1589  * Output the field into the report.
1590  */
1591
1592 static void hid_output_field(const struct hid_device *hid,
1593                              struct hid_field *field, __u8 *data)
1594 {
1595         unsigned count = field->report_count;
1596         unsigned offset = field->report_offset;
1597         unsigned size = field->report_size;
1598         unsigned n;
1599
1600         for (n = 0; n < count; n++) {
1601                 if (field->logical_minimum < 0) /* signed values */
1602                         implement(hid, data, offset + n * size, size,
1603                                   s32ton(field->value[n], size));
1604                 else                            /* unsigned values */
1605                         implement(hid, data, offset + n * size, size,
1606                                   field->value[n]);
1607         }
1608 }
1609
1610 /*
1611  * Compute the size of a report.
1612  */
1613 static size_t hid_compute_report_size(struct hid_report *report)
1614 {
1615         if (report->size)
1616                 return ((report->size - 1) >> 3) + 1;
1617
1618         return 0;
1619 }
1620
1621 /*
1622  * Create a report. 'data' has to be allocated using
1623  * hid_alloc_report_buf() so that it has proper size.
1624  */
1625
1626 void hid_output_report(struct hid_report *report, __u8 *data)
1627 {
1628         unsigned n;
1629
1630         if (report->id > 0)
1631                 *data++ = report->id;
1632
1633         memset(data, 0, hid_compute_report_size(report));
1634         for (n = 0; n < report->maxfield; n++)
1635                 hid_output_field(report->device, report->field[n], data);
1636 }
1637 EXPORT_SYMBOL_GPL(hid_output_report);
1638
1639 /*
1640  * Allocator for buffer that is going to be passed to hid_output_report()
1641  */
1642 u8 *hid_alloc_report_buf(struct hid_report *report, gfp_t flags)
1643 {
1644         /*
1645          * 7 extra bytes are necessary to achieve proper functionality
1646          * of implement() working on 8 byte chunks
1647          */
1648
1649         u32 len = hid_report_len(report) + 7;
1650
1651         return kmalloc(len, flags);
1652 }
1653 EXPORT_SYMBOL_GPL(hid_alloc_report_buf);
1654
1655 /*
1656  * Set a field value. The report this field belongs to has to be
1657  * created and transferred to the device, to set this value in the
1658  * device.
1659  */
1660
1661 int hid_set_field(struct hid_field *field, unsigned offset, __s32 value)
1662 {
1663         unsigned size;
1664
1665         if (!field)
1666                 return -1;
1667
1668         size = field->report_size;
1669
1670         hid_dump_input(field->report->device, field->usage + offset, value);
1671
1672         if (offset >= field->report_count) {
1673                 hid_err(field->report->device, "offset (%d) exceeds report_count (%d)\n",
1674                                 offset, field->report_count);
1675                 return -1;
1676         }
1677         if (field->logical_minimum < 0) {
1678                 if (value != snto32(s32ton(value, size), size)) {
1679                         hid_err(field->report->device, "value %d is out of range\n", value);
1680                         return -1;
1681                 }
1682         }
1683         field->value[offset] = value;
1684         return 0;
1685 }
1686 EXPORT_SYMBOL_GPL(hid_set_field);
1687
1688 static struct hid_report *hid_get_report(struct hid_report_enum *report_enum,
1689                 const u8 *data)
1690 {
1691         struct hid_report *report;
1692         unsigned int n = 0;     /* Normally report number is 0 */
1693
1694         /* Device uses numbered reports, data[0] is report number */
1695         if (report_enum->numbered)
1696                 n = *data;
1697
1698         report = report_enum->report_id_hash[n];
1699         if (report == NULL)
1700                 dbg_hid("undefined report_id %u received\n", n);
1701
1702         return report;
1703 }
1704
1705 /*
1706  * Implement a generic .request() callback, using .raw_request()
1707  * DO NOT USE in hid drivers directly, but through hid_hw_request instead.
1708  */
1709 int __hid_request(struct hid_device *hid, struct hid_report *report,
1710                 int reqtype)
1711 {
1712         char *buf;
1713         int ret;
1714         u32 len;
1715
1716         buf = hid_alloc_report_buf(report, GFP_KERNEL);
1717         if (!buf)
1718                 return -ENOMEM;
1719
1720         len = hid_report_len(report);
1721
1722         if (reqtype == HID_REQ_SET_REPORT)
1723                 hid_output_report(report, buf);
1724
1725         ret = hid->ll_driver->raw_request(hid, report->id, buf, len,
1726                                           report->type, reqtype);
1727         if (ret < 0) {
1728                 dbg_hid("unable to complete request: %d\n", ret);
1729                 goto out;
1730         }
1731
1732         if (reqtype == HID_REQ_GET_REPORT)
1733                 hid_input_report(hid, report->type, buf, ret, 0);
1734
1735         ret = 0;
1736
1737 out:
1738         kfree(buf);
1739         return ret;
1740 }
1741 EXPORT_SYMBOL_GPL(__hid_request);
1742
1743 int hid_report_raw_event(struct hid_device *hid, int type, u8 *data, u32 size,
1744                 int interrupt)
1745 {
1746         struct hid_report_enum *report_enum = hid->report_enum + type;
1747         struct hid_report *report;
1748         struct hid_driver *hdrv;
1749         unsigned int a;
1750         u32 rsize, csize = size;
1751         u8 *cdata = data;
1752         int ret = 0;
1753
1754         report = hid_get_report(report_enum, data);
1755         if (!report)
1756                 goto out;
1757
1758         if (report_enum->numbered) {
1759                 cdata++;
1760                 csize--;
1761         }
1762
1763         rsize = hid_compute_report_size(report);
1764
1765         if (report_enum->numbered && rsize >= HID_MAX_BUFFER_SIZE)
1766                 rsize = HID_MAX_BUFFER_SIZE - 1;
1767         else if (rsize > HID_MAX_BUFFER_SIZE)
1768                 rsize = HID_MAX_BUFFER_SIZE;
1769
1770         if (csize < rsize) {
1771                 dbg_hid("report %d is too short, (%d < %d)\n", report->id,
1772                                 csize, rsize);
1773                 memset(cdata + csize, 0, rsize - csize);
1774         }
1775
1776         if ((hid->claimed & HID_CLAIMED_HIDDEV) && hid->hiddev_report_event)
1777                 hid->hiddev_report_event(hid, report);
1778         if (hid->claimed & HID_CLAIMED_HIDRAW) {
1779                 ret = hidraw_report_event(hid, data, size);
1780                 if (ret)
1781                         goto out;
1782         }
1783
1784         if (hid->claimed != HID_CLAIMED_HIDRAW && report->maxfield) {
1785                 for (a = 0; a < report->maxfield; a++)
1786                         hid_input_field(hid, report->field[a], cdata, interrupt);
1787                 hdrv = hid->driver;
1788                 if (hdrv && hdrv->report)
1789                         hdrv->report(hid, report);
1790         }
1791
1792         if (hid->claimed & HID_CLAIMED_INPUT)
1793                 hidinput_report_event(hid, report);
1794 out:
1795         return ret;
1796 }
1797 EXPORT_SYMBOL_GPL(hid_report_raw_event);
1798
1799 /**
1800  * hid_input_report - report data from lower layer (usb, bt...)
1801  *
1802  * @hid: hid device
1803  * @type: HID report type (HID_*_REPORT)
1804  * @data: report contents
1805  * @size: size of data parameter
1806  * @interrupt: distinguish between interrupt and control transfers
1807  *
1808  * This is data entry for lower layers.
1809  */
1810 int hid_input_report(struct hid_device *hid, int type, u8 *data, u32 size, int interrupt)
1811 {
1812         struct hid_report_enum *report_enum;
1813         struct hid_driver *hdrv;
1814         struct hid_report *report;
1815         int ret = 0;
1816
1817         if (!hid)
1818                 return -ENODEV;
1819
1820         if (down_trylock(&hid->driver_input_lock))
1821                 return -EBUSY;
1822
1823         if (!hid->driver) {
1824                 ret = -ENODEV;
1825                 goto unlock;
1826         }
1827         report_enum = hid->report_enum + type;
1828         hdrv = hid->driver;
1829
1830         if (!size) {
1831                 dbg_hid("empty report\n");
1832                 ret = -1;
1833                 goto unlock;
1834         }
1835
1836         /* Avoid unnecessary overhead if debugfs is disabled */
1837         if (!list_empty(&hid->debug_list))
1838                 hid_dump_report(hid, type, data, size);
1839
1840         report = hid_get_report(report_enum, data);
1841
1842         if (!report) {
1843                 ret = -1;
1844                 goto unlock;
1845         }
1846
1847         if (hdrv && hdrv->raw_event && hid_match_report(hid, report)) {
1848                 ret = hdrv->raw_event(hid, report, data, size);
1849                 if (ret < 0)
1850                         goto unlock;
1851         }
1852
1853         ret = hid_report_raw_event(hid, type, data, size, interrupt);
1854
1855 unlock:
1856         up(&hid->driver_input_lock);
1857         return ret;
1858 }
1859 EXPORT_SYMBOL_GPL(hid_input_report);
1860
1861 bool hid_match_one_id(const struct hid_device *hdev,
1862                       const struct hid_device_id *id)
1863 {
1864         return (id->bus == HID_BUS_ANY || id->bus == hdev->bus) &&
1865                 (id->group == HID_GROUP_ANY || id->group == hdev->group) &&
1866                 (id->vendor == HID_ANY_ID || id->vendor == hdev->vendor) &&
1867                 (id->product == HID_ANY_ID || id->product == hdev->product);
1868 }
1869
1870 const struct hid_device_id *hid_match_id(const struct hid_device *hdev,
1871                 const struct hid_device_id *id)
1872 {
1873         for (; id->bus; id++)
1874                 if (hid_match_one_id(hdev, id))
1875                         return id;
1876
1877         return NULL;
1878 }
1879
1880 static const struct hid_device_id hid_hiddev_list[] = {
1881         { HID_USB_DEVICE(USB_VENDOR_ID_MGE, USB_DEVICE_ID_MGE_UPS) },
1882         { HID_USB_DEVICE(USB_VENDOR_ID_MGE, USB_DEVICE_ID_MGE_UPS1) },
1883         { }
1884 };
1885
1886 static bool hid_hiddev(struct hid_device *hdev)
1887 {
1888         return !!hid_match_id(hdev, hid_hiddev_list);
1889 }
1890
1891
1892 static ssize_t
1893 read_report_descriptor(struct file *filp, struct kobject *kobj,
1894                 struct bin_attribute *attr,
1895                 char *buf, loff_t off, size_t count)
1896 {
1897         struct device *dev = kobj_to_dev(kobj);
1898         struct hid_device *hdev = to_hid_device(dev);
1899
1900         if (off >= hdev->rsize)
1901                 return 0;
1902
1903         if (off + count > hdev->rsize)
1904                 count = hdev->rsize - off;
1905
1906         memcpy(buf, hdev->rdesc + off, count);
1907
1908         return count;
1909 }
1910
1911 static ssize_t
1912 show_country(struct device *dev, struct device_attribute *attr,
1913                 char *buf)
1914 {
1915         struct hid_device *hdev = to_hid_device(dev);
1916
1917         return sprintf(buf, "%02x\n", hdev->country & 0xff);
1918 }
1919
1920 static struct bin_attribute dev_bin_attr_report_desc = {
1921         .attr = { .name = "report_descriptor", .mode = 0444 },
1922         .read = read_report_descriptor,
1923         .size = HID_MAX_DESCRIPTOR_SIZE,
1924 };
1925
1926 static const struct device_attribute dev_attr_country = {
1927         .attr = { .name = "country", .mode = 0444 },
1928         .show = show_country,
1929 };
1930
1931 int hid_connect(struct hid_device *hdev, unsigned int connect_mask)
1932 {
1933         static const char *types[] = { "Device", "Pointer", "Mouse", "Device",
1934                 "Joystick", "Gamepad", "Keyboard", "Keypad",
1935                 "Multi-Axis Controller"
1936         };
1937         const char *type, *bus;
1938         char buf[64] = "";
1939         unsigned int i;
1940         int len;
1941         int ret;
1942
1943         if (hdev->quirks & HID_QUIRK_HIDDEV_FORCE)
1944                 connect_mask |= (HID_CONNECT_HIDDEV_FORCE | HID_CONNECT_HIDDEV);
1945         if (hdev->quirks & HID_QUIRK_HIDINPUT_FORCE)
1946                 connect_mask |= HID_CONNECT_HIDINPUT_FORCE;
1947         if (hdev->bus != BUS_USB)
1948                 connect_mask &= ~HID_CONNECT_HIDDEV;
1949         if (hid_hiddev(hdev))
1950                 connect_mask |= HID_CONNECT_HIDDEV_FORCE;
1951
1952         if ((connect_mask & HID_CONNECT_HIDINPUT) && !hidinput_connect(hdev,
1953                                 connect_mask & HID_CONNECT_HIDINPUT_FORCE))
1954                 hdev->claimed |= HID_CLAIMED_INPUT;
1955
1956         if ((connect_mask & HID_CONNECT_HIDDEV) && hdev->hiddev_connect &&
1957                         !hdev->hiddev_connect(hdev,
1958                                 connect_mask & HID_CONNECT_HIDDEV_FORCE))
1959                 hdev->claimed |= HID_CLAIMED_HIDDEV;
1960         if ((connect_mask & HID_CONNECT_HIDRAW) && !hidraw_connect(hdev))
1961                 hdev->claimed |= HID_CLAIMED_HIDRAW;
1962
1963         if (connect_mask & HID_CONNECT_DRIVER)
1964                 hdev->claimed |= HID_CLAIMED_DRIVER;
1965
1966         /* Drivers with the ->raw_event callback set are not required to connect
1967          * to any other listener. */
1968         if (!hdev->claimed && !hdev->driver->raw_event) {
1969                 hid_err(hdev, "device has no listeners, quitting\n");
1970                 return -ENODEV;
1971         }
1972
1973         if ((hdev->claimed & HID_CLAIMED_INPUT) &&
1974                         (connect_mask & HID_CONNECT_FF) && hdev->ff_init)
1975                 hdev->ff_init(hdev);
1976
1977         len = 0;
1978         if (hdev->claimed & HID_CLAIMED_INPUT)
1979                 len += sprintf(buf + len, "input");
1980         if (hdev->claimed & HID_CLAIMED_HIDDEV)
1981                 len += sprintf(buf + len, "%shiddev%d", len ? "," : "",
1982                                 ((struct hiddev *)hdev->hiddev)->minor);
1983         if (hdev->claimed & HID_CLAIMED_HIDRAW)
1984                 len += sprintf(buf + len, "%shidraw%d", len ? "," : "",
1985                                 ((struct hidraw *)hdev->hidraw)->minor);
1986
1987         type = "Device";
1988         for (i = 0; i < hdev->maxcollection; i++) {
1989                 struct hid_collection *col = &hdev->collection[i];
1990                 if (col->type == HID_COLLECTION_APPLICATION &&
1991                    (col->usage & HID_USAGE_PAGE) == HID_UP_GENDESK &&
1992                    (col->usage & 0xffff) < ARRAY_SIZE(types)) {
1993                         type = types[col->usage & 0xffff];
1994                         break;
1995                 }
1996         }
1997
1998         switch (hdev->bus) {
1999         case BUS_USB:
2000                 bus = "USB";
2001                 break;
2002         case BUS_BLUETOOTH:
2003                 bus = "BLUETOOTH";
2004                 break;
2005         case BUS_I2C:
2006                 bus = "I2C";
2007                 break;
2008         case BUS_VIRTUAL:
2009                 bus = "VIRTUAL";
2010                 break;
2011         default:
2012                 bus = "<UNKNOWN>";
2013         }
2014
2015         ret = device_create_file(&hdev->dev, &dev_attr_country);
2016         if (ret)
2017                 hid_warn(hdev,
2018                          "can't create sysfs country code attribute err: %d\n", ret);
2019
2020         hid_info(hdev, "%s: %s HID v%x.%02x %s [%s] on %s\n",
2021                  buf, bus, hdev->version >> 8, hdev->version & 0xff,
2022                  type, hdev->name, hdev->phys);
2023
2024         return 0;
2025 }
2026 EXPORT_SYMBOL_GPL(hid_connect);
2027
2028 void hid_disconnect(struct hid_device *hdev)
2029 {
2030         device_remove_file(&hdev->dev, &dev_attr_country);
2031         if (hdev->claimed & HID_CLAIMED_INPUT)
2032                 hidinput_disconnect(hdev);
2033         if (hdev->claimed & HID_CLAIMED_HIDDEV)
2034                 hdev->hiddev_disconnect(hdev);
2035         if (hdev->claimed & HID_CLAIMED_HIDRAW)
2036                 hidraw_disconnect(hdev);
2037         hdev->claimed = 0;
2038 }
2039 EXPORT_SYMBOL_GPL(hid_disconnect);
2040
2041 /**
2042  * hid_hw_start - start underlying HW
2043  * @hdev: hid device
2044  * @connect_mask: which outputs to connect, see HID_CONNECT_*
2045  *
2046  * Call this in probe function *after* hid_parse. This will setup HW
2047  * buffers and start the device (if not defeirred to device open).
2048  * hid_hw_stop must be called if this was successful.
2049  */
2050 int hid_hw_start(struct hid_device *hdev, unsigned int connect_mask)
2051 {
2052         int error;
2053
2054         error = hdev->ll_driver->start(hdev);
2055         if (error)
2056                 return error;
2057
2058         if (connect_mask) {
2059                 error = hid_connect(hdev, connect_mask);
2060                 if (error) {
2061                         hdev->ll_driver->stop(hdev);
2062                         return error;
2063                 }
2064         }
2065
2066         return 0;
2067 }
2068 EXPORT_SYMBOL_GPL(hid_hw_start);
2069
2070 /**
2071  * hid_hw_stop - stop underlying HW
2072  * @hdev: hid device
2073  *
2074  * This is usually called from remove function or from probe when something
2075  * failed and hid_hw_start was called already.
2076  */
2077 void hid_hw_stop(struct hid_device *hdev)
2078 {
2079         hid_disconnect(hdev);
2080         hdev->ll_driver->stop(hdev);
2081 }
2082 EXPORT_SYMBOL_GPL(hid_hw_stop);
2083
2084 /**
2085  * hid_hw_open - signal underlying HW to start delivering events
2086  * @hdev: hid device
2087  *
2088  * Tell underlying HW to start delivering events from the device.
2089  * This function should be called sometime after successful call
2090  * to hid_hw_start().
2091  */
2092 int hid_hw_open(struct hid_device *hdev)
2093 {
2094         int ret;
2095
2096         ret = mutex_lock_killable(&hdev->ll_open_lock);
2097         if (ret)
2098                 return ret;
2099
2100         if (!hdev->ll_open_count++) {
2101                 ret = hdev->ll_driver->open(hdev);
2102                 if (ret)
2103                         hdev->ll_open_count--;
2104         }
2105
2106         mutex_unlock(&hdev->ll_open_lock);
2107         return ret;
2108 }
2109 EXPORT_SYMBOL_GPL(hid_hw_open);
2110
2111 /**
2112  * hid_hw_close - signal underlaying HW to stop delivering events
2113  *
2114  * @hdev: hid device
2115  *
2116  * This function indicates that we are not interested in the events
2117  * from this device anymore. Delivery of events may or may not stop,
2118  * depending on the number of users still outstanding.
2119  */
2120 void hid_hw_close(struct hid_device *hdev)
2121 {
2122         mutex_lock(&hdev->ll_open_lock);
2123         if (!--hdev->ll_open_count)
2124                 hdev->ll_driver->close(hdev);
2125         mutex_unlock(&hdev->ll_open_lock);
2126 }
2127 EXPORT_SYMBOL_GPL(hid_hw_close);
2128
2129 struct hid_dynid {
2130         struct list_head list;
2131         struct hid_device_id id;
2132 };
2133
2134 /**
2135  * new_id_store - add a new HID device ID to this driver and re-probe devices
2136  * @drv: target device driver
2137  * @buf: buffer for scanning device ID data
2138  * @count: input size
2139  *
2140  * Adds a new dynamic hid device ID to this driver,
2141  * and causes the driver to probe for all devices again.
2142  */
2143 static ssize_t new_id_store(struct device_driver *drv, const char *buf,
2144                 size_t count)
2145 {
2146         struct hid_driver *hdrv = to_hid_driver(drv);
2147         struct hid_dynid *dynid;
2148         __u32 bus, vendor, product;
2149         unsigned long driver_data = 0;
2150         int ret;
2151
2152         ret = sscanf(buf, "%x %x %x %lx",
2153                         &bus, &vendor, &product, &driver_data);
2154         if (ret < 3)
2155                 return -EINVAL;
2156
2157         dynid = kzalloc(sizeof(*dynid), GFP_KERNEL);
2158         if (!dynid)
2159                 return -ENOMEM;
2160
2161         dynid->id.bus = bus;
2162         dynid->id.group = HID_GROUP_ANY;
2163         dynid->id.vendor = vendor;
2164         dynid->id.product = product;
2165         dynid->id.driver_data = driver_data;
2166
2167         spin_lock(&hdrv->dyn_lock);
2168         list_add_tail(&dynid->list, &hdrv->dyn_list);
2169         spin_unlock(&hdrv->dyn_lock);
2170
2171         ret = driver_attach(&hdrv->driver);
2172
2173         return ret ? : count;
2174 }
2175 static DRIVER_ATTR_WO(new_id);
2176
2177 static struct attribute *hid_drv_attrs[] = {
2178         &driver_attr_new_id.attr,
2179         NULL,
2180 };
2181 ATTRIBUTE_GROUPS(hid_drv);
2182
2183 static void hid_free_dynids(struct hid_driver *hdrv)
2184 {
2185         struct hid_dynid *dynid, *n;
2186
2187         spin_lock(&hdrv->dyn_lock);
2188         list_for_each_entry_safe(dynid, n, &hdrv->dyn_list, list) {
2189                 list_del(&dynid->list);
2190                 kfree(dynid);
2191         }
2192         spin_unlock(&hdrv->dyn_lock);
2193 }
2194
2195 const struct hid_device_id *hid_match_device(struct hid_device *hdev,
2196                                              struct hid_driver *hdrv)
2197 {
2198         struct hid_dynid *dynid;
2199
2200         spin_lock(&hdrv->dyn_lock);
2201         list_for_each_entry(dynid, &hdrv->dyn_list, list) {
2202                 if (hid_match_one_id(hdev, &dynid->id)) {
2203                         spin_unlock(&hdrv->dyn_lock);
2204                         return &dynid->id;
2205                 }
2206         }
2207         spin_unlock(&hdrv->dyn_lock);
2208
2209         return hid_match_id(hdev, hdrv->id_table);
2210 }
2211 EXPORT_SYMBOL_GPL(hid_match_device);
2212
2213 static int hid_bus_match(struct device *dev, struct device_driver *drv)
2214 {
2215         struct hid_driver *hdrv = to_hid_driver(drv);
2216         struct hid_device *hdev = to_hid_device(dev);
2217
2218         return hid_match_device(hdev, hdrv) != NULL;
2219 }
2220
2221 /**
2222  * hid_compare_device_paths - check if both devices share the same path
2223  * @hdev_a: hid device
2224  * @hdev_b: hid device
2225  * @separator: char to use as separator
2226  *
2227  * Check if two devices share the same path up to the last occurrence of
2228  * the separator char. Both paths must exist (i.e., zero-length paths
2229  * don't match).
2230  */
2231 bool hid_compare_device_paths(struct hid_device *hdev_a,
2232                               struct hid_device *hdev_b, char separator)
2233 {
2234         int n1 = strrchr(hdev_a->phys, separator) - hdev_a->phys;
2235         int n2 = strrchr(hdev_b->phys, separator) - hdev_b->phys;
2236
2237         if (n1 != n2 || n1 <= 0 || n2 <= 0)
2238                 return false;
2239
2240         return !strncmp(hdev_a->phys, hdev_b->phys, n1);
2241 }
2242 EXPORT_SYMBOL_GPL(hid_compare_device_paths);
2243
2244 static int hid_device_probe(struct device *dev)
2245 {
2246         struct hid_driver *hdrv = to_hid_driver(dev->driver);
2247         struct hid_device *hdev = to_hid_device(dev);
2248         const struct hid_device_id *id;
2249         int ret = 0;
2250
2251         if (down_interruptible(&hdev->driver_input_lock)) {
2252                 ret = -EINTR;
2253                 goto end;
2254         }
2255         hdev->io_started = false;
2256
2257         clear_bit(ffs(HID_STAT_REPROBED), &hdev->status);
2258
2259         if (!hdev->driver) {
2260                 id = hid_match_device(hdev, hdrv);
2261                 if (id == NULL) {
2262                         ret = -ENODEV;
2263                         goto unlock;
2264                 }
2265
2266                 if (hdrv->match) {
2267                         if (!hdrv->match(hdev, hid_ignore_special_drivers)) {
2268                                 ret = -ENODEV;
2269                                 goto unlock;
2270                         }
2271                 } else {
2272                         /*
2273                          * hid-generic implements .match(), so if
2274                          * hid_ignore_special_drivers is set, we can safely
2275                          * return.
2276                          */
2277                         if (hid_ignore_special_drivers) {
2278                                 ret = -ENODEV;
2279                                 goto unlock;
2280                         }
2281                 }
2282
2283                 /* reset the quirks that has been previously set */
2284                 hdev->quirks = hid_lookup_quirk(hdev);
2285                 hdev->driver = hdrv;
2286                 if (hdrv->probe) {
2287                         ret = hdrv->probe(hdev, id);
2288                 } else { /* default probe */
2289                         ret = hid_open_report(hdev);
2290                         if (!ret)
2291                                 ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
2292                 }
2293                 if (ret) {
2294                         hid_close_report(hdev);
2295                         hdev->driver = NULL;
2296                 }
2297         }
2298 unlock:
2299         if (!hdev->io_started)
2300                 up(&hdev->driver_input_lock);
2301 end:
2302         return ret;
2303 }
2304
2305 static int hid_device_remove(struct device *dev)
2306 {
2307         struct hid_device *hdev = to_hid_device(dev);
2308         struct hid_driver *hdrv;
2309         int ret = 0;
2310
2311         if (down_interruptible(&hdev->driver_input_lock)) {
2312                 ret = -EINTR;
2313                 goto end;
2314         }
2315         hdev->io_started = false;
2316
2317         hdrv = hdev->driver;
2318         if (hdrv) {
2319                 if (hdrv->remove)
2320                         hdrv->remove(hdev);
2321                 else /* default remove */
2322                         hid_hw_stop(hdev);
2323                 hid_close_report(hdev);
2324                 hdev->driver = NULL;
2325         }
2326
2327         if (!hdev->io_started)
2328                 up(&hdev->driver_input_lock);
2329 end:
2330         return ret;
2331 }
2332
2333 static ssize_t modalias_show(struct device *dev, struct device_attribute *a,
2334                              char *buf)
2335 {
2336         struct hid_device *hdev = container_of(dev, struct hid_device, dev);
2337
2338         return scnprintf(buf, PAGE_SIZE, "hid:b%04Xg%04Xv%08Xp%08X\n",
2339                          hdev->bus, hdev->group, hdev->vendor, hdev->product);
2340 }
2341 static DEVICE_ATTR_RO(modalias);
2342
2343 static struct attribute *hid_dev_attrs[] = {
2344         &dev_attr_modalias.attr,
2345         NULL,
2346 };
2347 static struct bin_attribute *hid_dev_bin_attrs[] = {
2348         &dev_bin_attr_report_desc,
2349         NULL
2350 };
2351 static const struct attribute_group hid_dev_group = {
2352         .attrs = hid_dev_attrs,
2353         .bin_attrs = hid_dev_bin_attrs,
2354 };
2355 __ATTRIBUTE_GROUPS(hid_dev);
2356
2357 static int hid_uevent(struct device *dev, struct kobj_uevent_env *env)
2358 {
2359         struct hid_device *hdev = to_hid_device(dev);
2360
2361         if (add_uevent_var(env, "HID_ID=%04X:%08X:%08X",
2362                         hdev->bus, hdev->vendor, hdev->product))
2363                 return -ENOMEM;
2364
2365         if (add_uevent_var(env, "HID_NAME=%s", hdev->name))
2366                 return -ENOMEM;
2367
2368         if (add_uevent_var(env, "HID_PHYS=%s", hdev->phys))
2369                 return -ENOMEM;
2370
2371         if (add_uevent_var(env, "HID_UNIQ=%s", hdev->uniq))
2372                 return -ENOMEM;
2373
2374         if (add_uevent_var(env, "MODALIAS=hid:b%04Xg%04Xv%08Xp%08X",
2375                            hdev->bus, hdev->group, hdev->vendor, hdev->product))
2376                 return -ENOMEM;
2377
2378         return 0;
2379 }
2380
2381 struct bus_type hid_bus_type = {
2382         .name           = "hid",
2383         .dev_groups     = hid_dev_groups,
2384         .drv_groups     = hid_drv_groups,
2385         .match          = hid_bus_match,
2386         .probe          = hid_device_probe,
2387         .remove         = hid_device_remove,
2388         .uevent         = hid_uevent,
2389 };
2390 EXPORT_SYMBOL(hid_bus_type);
2391
2392 int hid_add_device(struct hid_device *hdev)
2393 {
2394         static atomic_t id = ATOMIC_INIT(0);
2395         int ret;
2396
2397         if (WARN_ON(hdev->status & HID_STAT_ADDED))
2398                 return -EBUSY;
2399
2400         hdev->quirks = hid_lookup_quirk(hdev);
2401
2402         /* we need to kill them here, otherwise they will stay allocated to
2403          * wait for coming driver */
2404         if (hid_ignore(hdev))
2405                 return -ENODEV;
2406
2407         /*
2408          * Check for the mandatory transport channel.
2409          */
2410          if (!hdev->ll_driver->raw_request) {
2411                 hid_err(hdev, "transport driver missing .raw_request()\n");
2412                 return -EINVAL;
2413          }
2414
2415         /*
2416          * Read the device report descriptor once and use as template
2417          * for the driver-specific modifications.
2418          */
2419         ret = hdev->ll_driver->parse(hdev);
2420         if (ret)
2421                 return ret;
2422         if (!hdev->dev_rdesc)
2423                 return -ENODEV;
2424
2425         /*
2426          * Scan generic devices for group information
2427          */
2428         if (hid_ignore_special_drivers) {
2429                 hdev->group = HID_GROUP_GENERIC;
2430         } else if (!hdev->group &&
2431                    !(hdev->quirks & HID_QUIRK_HAVE_SPECIAL_DRIVER)) {
2432                 ret = hid_scan_report(hdev);
2433                 if (ret)
2434                         hid_warn(hdev, "bad device descriptor (%d)\n", ret);
2435         }
2436
2437         /* XXX hack, any other cleaner solution after the driver core
2438          * is converted to allow more than 20 bytes as the device name? */
2439         dev_set_name(&hdev->dev, "%04X:%04X:%04X.%04X", hdev->bus,
2440                      hdev->vendor, hdev->product, atomic_inc_return(&id));
2441
2442         hid_debug_register(hdev, dev_name(&hdev->dev));
2443         ret = device_add(&hdev->dev);
2444         if (!ret)
2445                 hdev->status |= HID_STAT_ADDED;
2446         else
2447                 hid_debug_unregister(hdev);
2448
2449         return ret;
2450 }
2451 EXPORT_SYMBOL_GPL(hid_add_device);
2452
2453 /**
2454  * hid_allocate_device - allocate new hid device descriptor
2455  *
2456  * Allocate and initialize hid device, so that hid_destroy_device might be
2457  * used to free it.
2458  *
2459  * New hid_device pointer is returned on success, otherwise ERR_PTR encoded
2460  * error value.
2461  */
2462 struct hid_device *hid_allocate_device(void)
2463 {
2464         struct hid_device *hdev;
2465         int ret = -ENOMEM;
2466
2467         hdev = kzalloc(sizeof(*hdev), GFP_KERNEL);
2468         if (hdev == NULL)
2469                 return ERR_PTR(ret);
2470
2471         device_initialize(&hdev->dev);
2472         hdev->dev.release = hid_device_release;
2473         hdev->dev.bus = &hid_bus_type;
2474         device_enable_async_suspend(&hdev->dev);
2475
2476         hid_close_report(hdev);
2477
2478         init_waitqueue_head(&hdev->debug_wait);
2479         INIT_LIST_HEAD(&hdev->debug_list);
2480         spin_lock_init(&hdev->debug_list_lock);
2481         sema_init(&hdev->driver_input_lock, 1);
2482         mutex_init(&hdev->ll_open_lock);
2483
2484         return hdev;
2485 }
2486 EXPORT_SYMBOL_GPL(hid_allocate_device);
2487
2488 static void hid_remove_device(struct hid_device *hdev)
2489 {
2490         if (hdev->status & HID_STAT_ADDED) {
2491                 device_del(&hdev->dev);
2492                 hid_debug_unregister(hdev);
2493                 hdev->status &= ~HID_STAT_ADDED;
2494         }
2495         kfree(hdev->dev_rdesc);
2496         hdev->dev_rdesc = NULL;
2497         hdev->dev_rsize = 0;
2498 }
2499
2500 /**
2501  * hid_destroy_device - free previously allocated device
2502  *
2503  * @hdev: hid device
2504  *
2505  * If you allocate hid_device through hid_allocate_device, you should ever
2506  * free by this function.
2507  */
2508 void hid_destroy_device(struct hid_device *hdev)
2509 {
2510         hid_remove_device(hdev);
2511         put_device(&hdev->dev);
2512 }
2513 EXPORT_SYMBOL_GPL(hid_destroy_device);
2514
2515
2516 static int __hid_bus_reprobe_drivers(struct device *dev, void *data)
2517 {
2518         struct hid_driver *hdrv = data;
2519         struct hid_device *hdev = to_hid_device(dev);
2520
2521         if (hdev->driver == hdrv &&
2522             !hdrv->match(hdev, hid_ignore_special_drivers) &&
2523             !test_and_set_bit(ffs(HID_STAT_REPROBED), &hdev->status))
2524                 return device_reprobe(dev);
2525
2526         return 0;
2527 }
2528
2529 static int __hid_bus_driver_added(struct device_driver *drv, void *data)
2530 {
2531         struct hid_driver *hdrv = to_hid_driver(drv);
2532
2533         if (hdrv->match) {
2534                 bus_for_each_dev(&hid_bus_type, NULL, hdrv,
2535                                  __hid_bus_reprobe_drivers);
2536         }
2537
2538         return 0;
2539 }
2540
2541 static int __bus_removed_driver(struct device_driver *drv, void *data)
2542 {
2543         return bus_rescan_devices(&hid_bus_type);
2544 }
2545
2546 int __hid_register_driver(struct hid_driver *hdrv, struct module *owner,
2547                 const char *mod_name)
2548 {
2549         int ret;
2550
2551         hdrv->driver.name = hdrv->name;
2552         hdrv->driver.bus = &hid_bus_type;
2553         hdrv->driver.owner = owner;
2554         hdrv->driver.mod_name = mod_name;
2555
2556         INIT_LIST_HEAD(&hdrv->dyn_list);
2557         spin_lock_init(&hdrv->dyn_lock);
2558
2559         ret = driver_register(&hdrv->driver);
2560
2561         if (ret == 0)
2562                 bus_for_each_drv(&hid_bus_type, NULL, NULL,
2563                                  __hid_bus_driver_added);
2564
2565         return ret;
2566 }
2567 EXPORT_SYMBOL_GPL(__hid_register_driver);
2568
2569 void hid_unregister_driver(struct hid_driver *hdrv)
2570 {
2571         driver_unregister(&hdrv->driver);
2572         hid_free_dynids(hdrv);
2573
2574         bus_for_each_drv(&hid_bus_type, NULL, hdrv, __bus_removed_driver);
2575 }
2576 EXPORT_SYMBOL_GPL(hid_unregister_driver);
2577
2578 int hid_check_keys_pressed(struct hid_device *hid)
2579 {
2580         struct hid_input *hidinput;
2581         int i;
2582
2583         if (!(hid->claimed & HID_CLAIMED_INPUT))
2584                 return 0;
2585
2586         list_for_each_entry(hidinput, &hid->inputs, list) {
2587                 for (i = 0; i < BITS_TO_LONGS(KEY_MAX); i++)
2588                         if (hidinput->input->key[i])
2589                                 return 1;
2590         }
2591
2592         return 0;
2593 }
2594 EXPORT_SYMBOL_GPL(hid_check_keys_pressed);
2595
2596 static int __init hid_init(void)
2597 {
2598         int ret;
2599
2600         if (hid_debug)
2601                 pr_warn("hid_debug is now used solely for parser and driver debugging.\n"
2602                         "debugfs is now used for inspecting the device (report descriptor, reports)\n");
2603
2604         ret = bus_register(&hid_bus_type);
2605         if (ret) {
2606                 pr_err("can't register hid bus\n");
2607                 goto err;
2608         }
2609
2610         ret = hidraw_init();
2611         if (ret)
2612                 goto err_bus;
2613
2614         hid_debug_init();
2615
2616         return 0;
2617 err_bus:
2618         bus_unregister(&hid_bus_type);
2619 err:
2620         return ret;
2621 }
2622
2623 static void __exit hid_exit(void)
2624 {
2625         hid_debug_exit();
2626         hidraw_exit();
2627         bus_unregister(&hid_bus_type);
2628         hid_quirks_exit(HID_BUS_ANY);
2629 }
2630
2631 module_init(hid_init);
2632 module_exit(hid_exit);
2633
2634 MODULE_AUTHOR("Andreas Gal");
2635 MODULE_AUTHOR("Vojtech Pavlik");
2636 MODULE_AUTHOR("Jiri Kosina");
2637 MODULE_LICENSE("GPL");