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 max_buffer_size = HID_MAX_BUFFER_SIZE;
 262         unsigned int usages;
 263         unsigned int offset;
 264         unsigned int i;
 265         unsigned int application;
 266
 267         application = hid_lookup_collection(parser, HID_COLLECTION_APPLICATION);
 268
 269         report = hid_register_report(parser->device, report_type,
 270                                      parser->global.report_id, application);
 271         if (!report) {
 272                 hid_err(parser->device, "hid_register_report failed\n");
 273                 return -1;
 274         }
 275
 276         /* Handle both signed and unsigned cases properly */
 277         if ((parser->global.logical_minimum < 0 &&
 278                 parser->global.logical_maximum <
 279                 parser->global.logical_minimum) ||
 280                 (parser->global.logical_minimum >= 0 &&
 281                 (__u32)parser->global.logical_maximum <
 282                 (__u32)parser->global.logical_minimum)) {
 283                 dbg_hid("logical range invalid 0x%x 0x%x\n",
 284                         parser->global.logical_minimum,
 285                         parser->global.logical_maximum);
 286                 return -1;
 287         }
 288
 289         offset = report->size;
 290         report->size += parser->global.report_size * parser->global.report_count;
 291
 292         if (parser->device->ll_driver->max_buffer_size)
 293                 max_buffer_size = parser->device->ll_driver->max_buffer_size;
 294
 295         /* Total size check: Allow for possible report index byte */
 296         if (report->size > (max_buffer_size - 1) << 3) {
 297                 hid_err(parser->device, "report is too long\n");
 298                 return -1;
 299         }
 300
 301         if (!parser->local.usage_index) /* Ignore padding fields */
 302                 return 0;
 303
 304         usages = max_t(unsigned, parser->local.usage_index,
 305                                  parser->global.report_count);
 306
 307         field = hid_register_field(report, usages);
 308         if (!field)
 309                 return 0;
 310
 311         field->physical = hid_lookup_collection(parser, HID_COLLECTION_PHYSICAL);
 312         field->logical = hid_lookup_collection(parser, HID_COLLECTION_LOGICAL);
 313         field->application = application;
 314
 315         for (i = 0; i < usages; i++) {
 316                 unsigned j = i;
 317                 /* Duplicate the last usage we parsed if we have excess values */
 318                 if (i >= parser->local.usage_index)
 319                         j = parser->local.usage_index - 1;
 320                 field->usage[i].hid = parser->local.usage[j];
 321                 field->usage[i].collection_index =
 322                         parser->local.collection_index[j];
 323                 field->usage[i].usage_index = i;
 324                 field->usage[i].resolution_multiplier = 1;
 325         }
 326
 327         field->maxusage = usages;
 328         field->flags = flags;
 329         field->report_offset = offset;
 330         field->report_type = report_type;
 331         field->report_size = parser->global.report_size;
 332         field->report_count = parser->global.report_count;
 333         field->logical_minimum = parser->global.logical_minimum;
 334         field->logical_maximum = parser->global.logical_maximum;
 335         field->physical_minimum = parser->global.physical_minimum;
 336         field->physical_maximum = parser->global.physical_maximum;
 337         field->unit_exponent = parser->global.unit_exponent;
 338         field->unit = parser->global.unit;
 339
 340         return 0;
 341 }
 342
 343 /*
 344  * Read data value from item.
 345  */
 346
 347 static u32 item_udata(struct hid_item *item)
 348 {
 349         switch (item->size) {
 350         case 1: return item->data.u8;
 351         case 2: return item->data.u16;
 352         case 4: return item->data.u32;
 353         }
 354         return 0;
 355 }
 356
 357 static s32 item_sdata(struct hid_item *item)
 358 {
 359         switch (item->size) {
 360         case 1: return item->data.s8;
 361         case 2: return item->data.s16;
 362         case 4: return item->data.s32;
 363         }
 364         return 0;
 365 }
 366
 367 /*
 368  * Process a global item.
 369  */
 370
 371 static int hid_parser_global(struct hid_parser *parser, struct hid_item *item)
 372 {
 373         __s32 raw_value;
 374         switch (item->tag) {
 375         case HID_GLOBAL_ITEM_TAG_PUSH:
 376
 377                 if (parser->global_stack_ptr == HID_GLOBAL_STACK_SIZE) {
 378                         hid_err(parser->device, "global environment stack overflow\n");
 379                         return -1;
 380                 }
 381
 382                 memcpy(parser->global_stack + parser->global_stack_ptr++,
 383                         &parser->global, sizeof(struct hid_global));
 384                 return 0;
 385
 386         case HID_GLOBAL_ITEM_TAG_POP:
 387
 388                 if (!parser->global_stack_ptr) {
 389                         hid_err(parser->device, "global environment stack underflow\n");
 390                         return -1;
 391                 }
 392
 393                 memcpy(&parser->global, parser->global_stack +
 394                         --parser->global_stack_ptr, sizeof(struct hid_global));
 395                 return 0;
 396
 397         case HID_GLOBAL_ITEM_TAG_USAGE_PAGE:
 398                 parser->global.usage_page = item_udata(item);
 399                 return 0;
 400
 401         case HID_GLOBAL_ITEM_TAG_LOGICAL_MINIMUM:
 402                 parser->global.logical_minimum = item_sdata(item);
 403                 return 0;
 404
 405         case HID_GLOBAL_ITEM_TAG_LOGICAL_MAXIMUM:
 406                 if (parser->global.logical_minimum < 0)
 407                         parser->global.logical_maximum = item_sdata(item);
 408                 else
 409                         parser->global.logical_maximum = item_udata(item);
 410                 return 0;
 411
 412         case HID_GLOBAL_ITEM_TAG_PHYSICAL_MINIMUM:
 413                 parser->global.physical_minimum = item_sdata(item);
 414                 return 0;
 415
 416         case HID_GLOBAL_ITEM_TAG_PHYSICAL_MAXIMUM:
 417                 if (parser->global.physical_minimum < 0)
 418                         parser->global.physical_maximum = item_sdata(item);
 419                 else
 420                         parser->global.physical_maximum = item_udata(item);
 421                 return 0;
 422
 423         case HID_GLOBAL_ITEM_TAG_UNIT_EXPONENT:
 424                 /* Many devices provide unit exponent as a two's complement
 425                  * nibble due to the common misunderstanding of HID
 426                  * specification 1.11, 6.2.2.7 Global Items. Attempt to handle
 427                  * both this and the standard encoding. */
 428                 raw_value = item_sdata(item);
 429                 if (!(raw_value & 0xfffffff0))
 430                         parser->global.unit_exponent = hid_snto32(raw_value, 4);
 431                 else
 432                         parser->global.unit_exponent = raw_value;
 433                 return 0;
 434
 435         case HID_GLOBAL_ITEM_TAG_UNIT:
 436                 parser->global.unit = item_udata(item);
 437                 return 0;
 438
 439         case HID_GLOBAL_ITEM_TAG_REPORT_SIZE:
 440                 parser->global.report_size = item_udata(item);
 441                 if (parser->global.report_size > 256) {
 442                         hid_err(parser->device, "invalid report_size %d\n",
 443                                         parser->global.report_size);
 444                         return -1;
 445                 }
 446                 return 0;
 447
 448         case HID_GLOBAL_ITEM_TAG_REPORT_COUNT:
 449                 parser->global.report_count = item_udata(item);
 450                 if (parser->global.report_count > HID_MAX_USAGES) {
 451                         hid_err(parser->device, "invalid report_count %d\n",
 452                                         parser->global.report_count);
 453                         return -1;
 454                 }
 455                 return 0;
 456
 457         case HID_GLOBAL_ITEM_TAG_REPORT_ID:
 458                 parser->global.report_id = item_udata(item);
 459                 if (parser->global.report_id == 0 ||
 460                     parser->global.report_id >= HID_MAX_IDS) {
 461                         hid_err(parser->device, "report_id %u is invalid\n",
 462                                 parser->global.report_id);
 463                         return -1;
 464                 }
 465                 return 0;
 466
 467         default:
 468                 hid_err(parser->device, "unknown global tag 0x%x\n", item->tag);
 469                 return -1;
 470         }
 471 }
 472
 473 /*
 474  * Process a local item.
 475  */
 476
 477 static int hid_parser_local(struct hid_parser *parser, struct hid_item *item)
 478 {
 479         __u32 data;
 480         unsigned n;
 481         __u32 count;
 482
 483         data = item_udata(item);
 484
 485         switch (item->tag) {
 486         case HID_LOCAL_ITEM_TAG_DELIMITER:
 487
 488                 if (data) {
 489                         /*
 490                          * We treat items before the first delimiter
 491                          * as global to all usage sets (branch 0).
 492                          * In the moment we process only these global
 493                          * items and the first delimiter set.
 494                          */
 495                         if (parser->local.delimiter_depth != 0) {
 496                                 hid_err(parser->device, "nested delimiters\n");
 497                                 return -1;
 498                         }
 499                         parser->local.delimiter_depth++;
 500                         parser->local.delimiter_branch++;
 501                 } else {
 502                         if (parser->local.delimiter_depth < 1) {
 503                                 hid_err(parser->device, "bogus close delimiter\n");
 504                                 return -1;
 505                         }
 506                         parser->local.delimiter_depth--;
 507                 }
 508                 return 0;
 509
 510         case HID_LOCAL_ITEM_TAG_USAGE:
 511
 512                 if (parser->local.delimiter_branch > 1) {
 513                         dbg_hid("alternative usage ignored\n");
 514                         return 0;
 515                 }
 516
 517                 return hid_add_usage(parser, data, item->size);
 518
 519         case HID_LOCAL_ITEM_TAG_USAGE_MINIMUM:
 520
 521                 if (parser->local.delimiter_branch > 1) {
 522                         dbg_hid("alternative usage ignored\n");
 523                         return 0;
 524                 }
 525
 526                 parser->local.usage_minimum = data;
 527                 return 0;
 528
 529         case HID_LOCAL_ITEM_TAG_USAGE_MAXIMUM:
 530
 531                 if (parser->local.delimiter_branch > 1) {
 532                         dbg_hid("alternative usage ignored\n");
 533                         return 0;
 534                 }
 535
 536                 count = data - parser->local.usage_minimum;
 537                 if (count + parser->local.usage_index >= HID_MAX_USAGES) {
 538                         /*
 539                          * We do not warn if the name is not set, we are
 540                          * actually pre-scanning the device.
 541                          */
 542                         if (dev_name(&parser->device->dev))
 543                                 hid_warn(parser->device,
 544                                          "ignoring exceeding usage max\n");
 545                         data = HID_MAX_USAGES - parser->local.usage_index +
 546                                 parser->local.usage_minimum - 1;
 547                         if (data <= 0) {
 548                                 hid_err(parser->device,
 549                                         "no more usage index available\n");
 550                                 return -1;
 551                         }
 552                 }
 553
 554                 for (n = parser->local.usage_minimum; n <= data; n++)
 555                         if (hid_add_usage(parser, n, item->size)) {
 556                                 dbg_hid("hid_add_usage failed\n");
 557                                 return -1;
 558                         }
 559                 return 0;
 560
 561         default:
 562
 563                 dbg_hid("unknown local item tag 0x%x\n", item->tag);
 564                 return 0;
 565         }
 566         return 0;
 567 }
 568
 569 /*
 570  * Concatenate Usage Pages into Usages where relevant:
 571  * As per specification, 6.2.2.8: "When the parser encounters a main item it
 572  * concatenates the last declared Usage Page with a Usage to form a complete
 573  * usage value."
 574  */
 575
 576 static void hid_concatenate_last_usage_page(struct hid_parser *parser)
 577 {
 578         int i;
 579         unsigned int usage_page;
 580         unsigned int current_page;
 581
 582         if (!parser->local.usage_index)
 583                 return;
 584
 585         usage_page = parser->global.usage_page;
 586
 587         /*
 588          * Concatenate usage page again only if last declared Usage Page
 589          * has not been already used in previous usages concatenation
 590          */
 591         for (i = parser->local.usage_index - 1; i >= 0; i--) {
 592                 if (parser->local.usage_size[i] > 2)
 593                         /* Ignore extended usages */
 594                         continue;
 595
 596                 current_page = parser->local.usage[i] >> 16;
 597                 if (current_page == usage_page)
 598                         break;
 599
 600                 complete_usage(parser, i);
 601         }
 602 }
 603
 604 /*
 605  * Process a main item.
 606  */
 607
 608 static int hid_parser_main(struct hid_parser *parser, struct hid_item *item)
 609 {
 610         __u32 data;
 611         int ret;
 612
 613         hid_concatenate_last_usage_page(parser);
 614
 615         data = item_udata(item);
 616
 617         switch (item->tag) {
 618         case HID_MAIN_ITEM_TAG_BEGIN_COLLECTION:
 619                 ret = open_collection(parser, data & 0xff);
 620                 break;
 621         case HID_MAIN_ITEM_TAG_END_COLLECTION:
 622                 ret = close_collection(parser);
 623                 break;
 624         case HID_MAIN_ITEM_TAG_INPUT:
 625                 ret = hid_add_field(parser, HID_INPUT_REPORT, data);
 626                 break;
 627         case HID_MAIN_ITEM_TAG_OUTPUT:
 628                 ret = hid_add_field(parser, HID_OUTPUT_REPORT, data);
 629                 break;
 630         case HID_MAIN_ITEM_TAG_FEATURE:
 631                 ret = hid_add_field(parser, HID_FEATURE_REPORT, data);
 632                 break;
 633         default:
 634                 hid_warn(parser->device, "unknown main item tag 0x%x\n", item->tag);
 635                 ret = 0;
 636         }
 637
 638         memset(&parser->local, 0, sizeof(parser->local));       /* Reset the local parser environment */
 639
 640         return ret;
 641 }
 642
 643 /*
 644  * Process a reserved item.
 645  */
 646
 647 static int hid_parser_reserved(struct hid_parser *parser, struct hid_item *item)
 648 {
 649         dbg_hid("reserved item type, tag 0x%x\n", item->tag);
 650         return 0;
 651 }
 652
 653 /*
 654  * Free a report and all registered fields. The field->usage and
 655  * field->value table's are allocated behind the field, so we need
 656  * only to free(field) itself.
 657  */
 658
 659 static void hid_free_report(struct hid_report *report)
 660 {
 661         unsigned n;
 662
 663         for (n = 0; n < report->maxfield; n++)
 664                 kfree(report->field[n]);
 665         kfree(report);
 666 }
 667
 668 /*
 669  * Close report. This function returns the device
 670  * state to the point prior to hid_open_report().
 671  */
 672 static void hid_close_report(struct hid_device *device)
 673 {
 674         unsigned i, j;
 675
 676         for (i = 0; i < HID_REPORT_TYPES; i++) {
 677                 struct hid_report_enum *report_enum = device->report_enum + i;
 678
 679                 for (j = 0; j < HID_MAX_IDS; j++) {
 680                         struct hid_report *report = report_enum->report_id_hash[j];
 681                         if (report)
 682                                 hid_free_report(report);
 683                 }
 684                 memset(report_enum, 0, sizeof(*report_enum));
 685                 INIT_LIST_HEAD(&report_enum->report_list);
 686         }
 687
 688         kfree(device->rdesc);
 689         device->rdesc = NULL;
 690         device->rsize = 0;
 691
 692         kfree(device->collection);
 693         device->collection = NULL;
 694         device->collection_size = 0;
 695         device->maxcollection = 0;
 696         device->maxapplication = 0;
 697
 698         device->status &= ~HID_STAT_PARSED;
 699 }
 700
 701 /*
 702  * Free a device structure, all reports, and all fields.
 703  */
 704
 705 static void hid_device_release(struct device *dev)
 706 {
 707         struct hid_device *hid = to_hid_device(dev);
 708
 709         hid_close_report(hid);
 710         kfree(hid->dev_rdesc);
 711         kfree(hid);
 712 }
 713
 714 /*
 715  * Fetch a report description item from the data stream. We support long
 716  * items, though they are not used yet.
 717  */
 718
 719 static u8 *fetch_item(__u8 *start, __u8 *end, struct hid_item *item)
 720 {
 721         u8 b;
 722
 723         if ((end - start) <= 0)
 724                 return NULL;
 725
 726         b = *start++;
 727
 728         item->type = (b >> 2) & 3;
 729         item->tag  = (b >> 4) & 15;
 730
 731         if (item->tag == HID_ITEM_TAG_LONG) {
 732
 733                 item->format = HID_ITEM_FORMAT_LONG;
 734
 735                 if ((end - start) < 2)
 736                         return NULL;
 737
 738                 item->size = *start++;
 739                 item->tag  = *start++;
 740
 741                 if ((end - start) < item->size)
 742                         return NULL;
 743
 744                 item->data.longdata = start;
 745                 start += item->size;
 746                 return start;
 747         }
 748
 749         item->format = HID_ITEM_FORMAT_SHORT;
 750         item->size = b & 3;
 751
 752         switch (item->size) {
 753         case 0:
 754                 return start;
 755
 756         case 1:
 757                 if ((end - start) < 1)
 758                         return NULL;
 759                 item->data.u8 = *start++;
 760                 return start;
 761
 762         case 2:
 763                 if ((end - start) < 2)
 764                         return NULL;
 765                 item->data.u16 = get_unaligned_le16(start);
 766                 start = (__u8 *)((__le16 *)start + 1);
 767                 return start;
 768
 769         case 3:
 770                 item->size++;
 771                 if ((end - start) < 4)
 772                         return NULL;
 773                 item->data.u32 = get_unaligned_le32(start);
 774                 start = (__u8 *)((__le32 *)start + 1);
 775                 return start;
 776         }
 777
 778         return NULL;
 779 }
 780
 781 static void hid_scan_input_usage(struct hid_parser *parser, u32 usage)
 782 {
 783         struct hid_device *hid = parser->device;
 784
 785         if (usage == HID_DG_CONTACTID)
 786                 hid->group = HID_GROUP_MULTITOUCH;
 787 }
 788
 789 static void hid_scan_feature_usage(struct hid_parser *parser, u32 usage)
 790 {
 791         if (usage == 0xff0000c5 && parser->global.report_count == 256 &&
 792             parser->global.report_size == 8)
 793                 parser->scan_flags |= HID_SCAN_FLAG_MT_WIN_8;
 794
 795         if (usage == 0xff0000c6 && parser->global.report_count == 1 &&
 796             parser->global.report_size == 8)
 797                 parser->scan_flags |= HID_SCAN_FLAG_MT_WIN_8;
 798 }
 799
 800 static void hid_scan_collection(struct hid_parser *parser, unsigned type)
 801 {
 802         struct hid_device *hid = parser->device;
 803         int i;
 804
 805         if (((parser->global.usage_page << 16) == HID_UP_SENSOR) &&
 806             type == HID_COLLECTION_PHYSICAL)
 807                 hid->group = HID_GROUP_SENSOR_HUB;
 808
 809         if (hid->vendor == USB_VENDOR_ID_MICROSOFT &&
 810             hid->product == USB_DEVICE_ID_MS_POWER_COVER &&
 811             hid->group == HID_GROUP_MULTITOUCH)
 812                 hid->group = HID_GROUP_GENERIC;
 813
 814         if ((parser->global.usage_page << 16) == HID_UP_GENDESK)
 815                 for (i = 0; i < parser->local.usage_index; i++)
 816                         if (parser->local.usage[i] == HID_GD_POINTER)
 817                                 parser->scan_flags |= HID_SCAN_FLAG_GD_POINTER;
 818
 819         if ((parser->global.usage_page << 16) >= HID_UP_MSVENDOR)
 820                 parser->scan_flags |= HID_SCAN_FLAG_VENDOR_SPECIFIC;
 821 }
 822
 823 static int hid_scan_main(struct hid_parser *parser, struct hid_item *item)
 824 {
 825         __u32 data;
 826         int i;
 827
 828         hid_concatenate_last_usage_page(parser);
 829
 830         data = item_udata(item);
 831
 832         switch (item->tag) {
 833         case HID_MAIN_ITEM_TAG_BEGIN_COLLECTION:
 834                 hid_scan_collection(parser, data & 0xff);
 835                 break;
 836         case HID_MAIN_ITEM_TAG_END_COLLECTION:
 837                 break;
 838         case HID_MAIN_ITEM_TAG_INPUT:
 839                 /* ignore constant inputs, they will be ignored by hid-input */
 840                 if (data & HID_MAIN_ITEM_CONSTANT)
 841                         break;
 842                 for (i = 0; i < parser->local.usage_index; i++)
 843                         hid_scan_input_usage(parser, parser->local.usage[i]);
 844                 break;
 845         case HID_MAIN_ITEM_TAG_OUTPUT:
 846                 break;
 847         case HID_MAIN_ITEM_TAG_FEATURE:
 848                 for (i = 0; i < parser->local.usage_index; i++)
 849                         hid_scan_feature_usage(parser, parser->local.usage[i]);
 850                 break;
 851         }
 852
 853         /* Reset the local parser environment */
 854         memset(&parser->local, 0, sizeof(parser->local));
 855
 856         return 0;
 857 }
 858
 859 /*
 860  * Scan a report descriptor before the device is added to the bus.
 861  * Sets device groups and other properties that determine what driver
 862  * to load.
 863  */
 864 static int hid_scan_report(struct hid_device *hid)
 865 {
 866         struct hid_parser *parser;
 867         struct hid_item item;
 868         __u8 *start = hid->dev_rdesc;
 869         __u8 *end = start + hid->dev_rsize;
 870         static int (*dispatch_type[])(struct hid_parser *parser,
 871                                       struct hid_item *item) = {
 872                 hid_scan_main,
 873                 hid_parser_global,
 874                 hid_parser_local,
 875                 hid_parser_reserved
 876         };
 877
 878         parser = vzalloc(sizeof(struct hid_parser));
 879         if (!parser)
 880                 return -ENOMEM;
 881
 882         parser->device = hid;
 883         hid->group = HID_GROUP_GENERIC;
 884
 885         /*
 886          * The parsing is simpler than the one in hid_open_report() as we should
 887          * be robust against hid errors. Those errors will be raised by
 888          * hid_open_report() anyway.
 889          */
 890         while ((start = fetch_item(start, end, &item)) != NULL)
 891                 dispatch_type[item.type](parser, &item);
 892
 893         /*
 894          * Handle special flags set during scanning.
 895          */
 896         if ((parser->scan_flags & HID_SCAN_FLAG_MT_WIN_8) &&
 897             (hid->group == HID_GROUP_MULTITOUCH))
 898                 hid->group = HID_GROUP_MULTITOUCH_WIN_8;
 899
 900         /*
 901          * Vendor specific handlings
 902          */
 903         switch (hid->vendor) {
 904         case USB_VENDOR_ID_WACOM:
 905                 hid->group = HID_GROUP_WACOM;
 906                 break;
 907         case USB_VENDOR_ID_SYNAPTICS:
 908                 if (hid->group == HID_GROUP_GENERIC)
 909                         if ((parser->scan_flags & HID_SCAN_FLAG_VENDOR_SPECIFIC)
 910                             && (parser->scan_flags & HID_SCAN_FLAG_GD_POINTER))
 911                                 /*
 912                                  * hid-rmi should take care of them,
 913                                  * not hid-generic
 914                                  */
 915                                 hid->group = HID_GROUP_RMI;
 916                 break;
 917         }
 918
 919         kfree(parser->collection_stack);
 920         vfree(parser);
 921         return 0;
 922 }
 923
 924 /**
 925  * hid_parse_report - parse device report
 926  *
 927  * @device: hid device
 928  * @start: report start
 929  * @size: report size
 930  *
 931  * Allocate the device report as read by the bus driver. This function should
 932  * only be called from parse() in ll drivers.
 933  */
 934 int hid_parse_report(struct hid_device *hid, __u8 *start, unsigned size)
 935 {
 936         hid->dev_rdesc = kmemdup(start, size, GFP_KERNEL);
 937         if (!hid->dev_rdesc)
 938                 return -ENOMEM;
 939         hid->dev_rsize = size;
 940         return 0;
 941 }
 942 EXPORT_SYMBOL_GPL(hid_parse_report);
 943
 944 static const char * const hid_report_names[] = {
 945         "HID_INPUT_REPORT",
 946         "HID_OUTPUT_REPORT",
 947         "HID_FEATURE_REPORT",
 948 };
 949 /**
 950  * hid_validate_values - validate existing device report's value indexes
 951  *
 952  * @device: hid device
 953  * @type: which report type to examine
 954  * @id: which report ID to examine (0 for first)
 955  * @field_index: which report field to examine
 956  * @report_counts: expected number of values
 957  *
 958  * Validate the number of values in a given field of a given report, after
 959  * parsing.
 960  */
 961 struct hid_report *hid_validate_values(struct hid_device *hid,
 962                                        unsigned int type, unsigned int id,
 963                                        unsigned int field_index,
 964                                        unsigned int report_counts)
 965 {
 966         struct hid_report *report;
 967
 968         if (type > HID_FEATURE_REPORT) {
 969                 hid_err(hid, "invalid HID report type %u\n", type);
 970                 return NULL;
 971         }
 972
 973         if (id >= HID_MAX_IDS) {
 974                 hid_err(hid, "invalid HID report id %u\n", id);
 975                 return NULL;
 976         }
 977
 978         /*
 979          * Explicitly not using hid_get_report() here since it depends on
 980          * ->numbered being checked, which may not always be the case when
 981          * drivers go to access report values.
 982          */
 983         if (id == 0) {
 984                 /*
 985                  * Validating on id 0 means we should examine the first
 986                  * report in the list.
 987                  */
 988                 report = list_first_entry_or_null(
 989                                 &hid->report_enum[type].report_list,
 990                                 struct hid_report, list);
 991         } else {
 992                 report = hid->report_enum[type].report_id_hash[id];
 993         }
 994         if (!report) {
 995                 hid_err(hid, "missing %s %u\n", hid_report_names[type], id);
 996                 return NULL;
 997         }
 998         if (report->maxfield <= field_index) {
 999                 hid_err(hid, "not enough fields in %s %u\n",
1000                         hid_report_names[type], id);
1001                 return NULL;
1002         }
1003         if (report->field[field_index]->report_count < report_counts) {
1004                 hid_err(hid, "not enough values in %s %u field %u\n",
1005                         hid_report_names[type], id, field_index);
1006                 return NULL;
1007         }
1008         return report;
1009 }
1010 EXPORT_SYMBOL_GPL(hid_validate_values);
1011
1012 static int hid_calculate_multiplier(struct hid_device *hid,
1013                                      struct hid_field *multiplier)
1014 {
1015         int m;
1016         __s32 v = *multiplier->value;
1017         __s32 lmin = multiplier->logical_minimum;
1018         __s32 lmax = multiplier->logical_maximum;
1019         __s32 pmin = multiplier->physical_minimum;
1020         __s32 pmax = multiplier->physical_maximum;
1021
1022         /*
1023          * "Because OS implementations will generally divide the control's
1024          * reported count by the Effective Resolution Multiplier, designers
1025          * should take care not to establish a potential Effective
1026          * Resolution Multiplier of zero."
1027          * HID Usage Table, v1.12, Section 4.3.1, p31
1028          */
1029         if (lmax - lmin == 0)
1030                 return 1;
1031         /*
1032          * Handling the unit exponent is left as an exercise to whoever
1033          * finds a device where that exponent is not 0.
1034          */
1035         m = ((v - lmin)/(lmax - lmin) * (pmax - pmin) + pmin);
1036         if (unlikely(multiplier->unit_exponent != 0)) {
1037                 hid_warn(hid,
1038                          "unsupported Resolution Multiplier unit exponent %d\n",
1039                          multiplier->unit_exponent);
1040         }
1041
1042         /* There are no devices with an effective multiplier > 255 */
1043         if (unlikely(m == 0 || m > 255 || m < -255)) {
1044                 hid_warn(hid, "unsupported Resolution Multiplier %d\n", m);
1045                 m = 1;
1046         }
1047
1048         return m;
1049 }
1050
1051 static void hid_apply_multiplier_to_field(struct hid_device *hid,
1052                                           struct hid_field *field,
1053                                           struct hid_collection *multiplier_collection,
1054                                           int effective_multiplier)
1055 {
1056         struct hid_collection *collection;
1057         struct hid_usage *usage;
1058         int i;
1059
1060         /*
1061          * If multiplier_collection is NULL, the multiplier applies
1062          * to all fields in the report.
1063          * Otherwise, it is the Logical Collection the multiplier applies to
1064          * but our field may be in a subcollection of that collection.
1065          */
1066         for (i = 0; i < field->maxusage; i++) {
1067                 usage = &field->usage[i];
1068
1069                 collection = &hid->collection[usage->collection_index];
1070                 while (collection->parent_idx != -1 &&
1071                        collection != multiplier_collection)
1072                         collection = &hid->collection[collection->parent_idx];
1073
1074                 if (collection->parent_idx != -1 ||
1075                     multiplier_collection == NULL)
1076                         usage->resolution_multiplier = effective_multiplier;
1077
1078         }
1079 }
1080
1081 static void hid_apply_multiplier(struct hid_device *hid,
1082                                  struct hid_field *multiplier)
1083 {
1084         struct hid_report_enum *rep_enum;
1085         struct hid_report *rep;
1086         struct hid_field *field;
1087         struct hid_collection *multiplier_collection;
1088         int effective_multiplier;
1089         int i;
1090
1091         /*
1092          * "The Resolution Multiplier control must be contained in the same
1093          * Logical Collection as the control(s) to which it is to be applied.
1094          * If no Resolution Multiplier is defined, then the Resolution
1095          * Multiplier defaults to 1.  If more than one control exists in a
1096          * Logical Collection, the Resolution Multiplier is associated with
1097          * all controls in the collection. If no Logical Collection is
1098          * defined, the Resolution Multiplier is associated with all
1099          * controls in the report."
1100          * HID Usage Table, v1.12, Section 4.3.1, p30
1101          *
1102          * Thus, search from the current collection upwards until we find a
1103          * logical collection. Then search all fields for that same parent
1104          * collection. Those are the fields the multiplier applies to.
1105          *
1106          * If we have more than one multiplier, it will overwrite the
1107          * applicable fields later.
1108          */
1109         multiplier_collection = &hid->collection[multiplier->usage->collection_index];
1110         while (multiplier_collection->parent_idx != -1 &&
1111                multiplier_collection->type != HID_COLLECTION_LOGICAL)
1112                 multiplier_collection = &hid->collection[multiplier_collection->parent_idx];
1113
1114         effective_multiplier = hid_calculate_multiplier(hid, multiplier);
1115
1116         rep_enum = &hid->report_enum[HID_INPUT_REPORT];
1117         list_for_each_entry(rep, &rep_enum->report_list, list) {
1118                 for (i = 0; i < rep->maxfield; i++) {
1119                         field = rep->field[i];
1120                         hid_apply_multiplier_to_field(hid, field,
1121                                                       multiplier_collection,
1122                                                       effective_multiplier);
1123                 }
1124         }
1125 }
1126
1127 /*
1128  * hid_setup_resolution_multiplier - set up all resolution multipliers
1129  *
1130  * @device: hid device
1131  *
1132  * Search for all Resolution Multiplier Feature Reports and apply their
1133  * value to all matching Input items. This only updates the internal struct
1134  * fields.
1135  *
1136  * The Resolution Multiplier is applied by the hardware. If the multiplier
1137  * is anything other than 1, the hardware will send pre-multiplied events
1138  * so that the same physical interaction generates an accumulated
1139  *      accumulated_value = value * * multiplier
1140  * This may be achieved by sending
1141  * - "value * multiplier" for each event, or
1142  * - "value" but "multiplier" times as frequently, or
1143  * - a combination of the above
1144  * The only guarantee is that the same physical interaction always generates
1145  * an accumulated 'value * multiplier'.
1146  *
1147  * This function must be called before any event processing and after
1148  * any SetRequest to the Resolution Multiplier.
1149  */
1150 void hid_setup_resolution_multiplier(struct hid_device *hid)
1151 {
1152         struct hid_report_enum *rep_enum;
1153         struct hid_report *rep;
1154         struct hid_usage *usage;
1155         int i, j;
1156
1157         rep_enum = &hid->report_enum[HID_FEATURE_REPORT];
1158         list_for_each_entry(rep, &rep_enum->report_list, list) {
1159                 for (i = 0; i < rep->maxfield; i++) {
1160                         /* Ignore if report count is out of bounds. */
1161                         if (rep->field[i]->report_count < 1)
1162                                 continue;
1163
1164                         for (j = 0; j < rep->field[i]->maxusage; j++) {
1165                                 usage = &rep->field[i]->usage[j];
1166                                 if (usage->hid == HID_GD_RESOLUTION_MULTIPLIER)
1167                                         hid_apply_multiplier(hid,
1168                                                              rep->field[i]);
1169                         }
1170                 }
1171         }
1172 }
1173 EXPORT_SYMBOL_GPL(hid_setup_resolution_multiplier);
1174
1175 /**
1176  * hid_open_report - open a driver-specific device report
1177  *
1178  * @device: hid device
1179  *
1180  * Parse a report description into a hid_device structure. Reports are
1181  * enumerated, fields are attached to these reports.
1182  * 0 returned on success, otherwise nonzero error value.
1183  *
1184  * This function (or the equivalent hid_parse() macro) should only be
1185  * called from probe() in drivers, before starting the device.
1186  */
1187 int hid_open_report(struct hid_device *device)
1188 {
1189         struct hid_parser *parser;
1190         struct hid_item item;
1191         unsigned int size;
1192         __u8 *start;
1193         __u8 *buf;
1194         __u8 *end;
1195         __u8 *next;
1196         int ret;
1197         int i;
1198         static int (*dispatch_type[])(struct hid_parser *parser,
1199                                       struct hid_item *item) = {
1200                 hid_parser_main,
1201                 hid_parser_global,
1202                 hid_parser_local,
1203                 hid_parser_reserved
1204         };
1205
1206         if (WARN_ON(device->status & HID_STAT_PARSED))
1207                 return -EBUSY;
1208
1209         start = device->dev_rdesc;
1210         if (WARN_ON(!start))
1211                 return -ENODEV;
1212         size = device->dev_rsize;
1213
1214         buf = kmemdup(start, size, GFP_KERNEL);
1215         if (buf == NULL)
1216                 return -ENOMEM;
1217
1218         if (device->driver->report_fixup)
1219                 start = device->driver->report_fixup(device, buf, &size);
1220         else
1221                 start = buf;
1222
1223         start = kmemdup(start, size, GFP_KERNEL);
1224         kfree(buf);
1225         if (start == NULL)
1226                 return -ENOMEM;
1227
1228         device->rdesc = start;
1229         device->rsize = size;
1230
1231         parser = vzalloc(sizeof(struct hid_parser));
1232         if (!parser) {
1233                 ret = -ENOMEM;
1234                 goto alloc_err;
1235         }
1236
1237         parser->device = device;
1238
1239         end = start + size;
1240
1241         device->collection = kcalloc(HID_DEFAULT_NUM_COLLECTIONS,
1242                                      sizeof(struct hid_collection), GFP_KERNEL);
1243         if (!device->collection) {
1244                 ret = -ENOMEM;
1245                 goto err;
1246         }
1247         device->collection_size = HID_DEFAULT_NUM_COLLECTIONS;
1248         for (i = 0; i < HID_DEFAULT_NUM_COLLECTIONS; i++)
1249                 device->collection[i].parent_idx = -1;
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         if (n > 32)
1314                 n = 32;
1315
1316         switch (n) {
1317         case 8:  return ((__s8)value);
1318         case 16: return ((__s16)value);
1319         case 32: return ((__s32)value);
1320         }
1321         return value & (1 << (n - 1)) ? value | (~0U << n) : value;
1322 }
1323
1324 s32 hid_snto32(__u32 value, unsigned n)
1325 {
1326         return snto32(value, n);
1327 }
1328 EXPORT_SYMBOL_GPL(hid_snto32);
1329
1330 /*
1331  * Convert a signed 32-bit integer to a signed n-bit integer.
1332  */
1333
1334 static u32 s32ton(__s32 value, unsigned n)
1335 {
1336         s32 a = value >> (n - 1);
1337         if (a && a != -1)
1338                 return value < 0 ? 1 << (n - 1) : (1 << (n - 1)) - 1;
1339         return value & ((1 << n) - 1);
1340 }
1341
1342 /*
1343  * Extract/implement a data field from/to a little endian report (bit array).
1344  *
1345  * Code sort-of follows HID spec:
1346  *     http://www.usb.org/developers/hidpage/HID1_11.pdf
1347  *
1348  * While the USB HID spec allows unlimited length bit fields in "report
1349  * descriptors", most devices never use more than 16 bits.
1350  * One model of UPS is claimed to report "LINEV" as a 32-bit field.
1351  * Search linux-kernel and linux-usb-devel archives for "hid-core extract".
1352  */
1353
1354 static u32 __extract(u8 *report, unsigned offset, int n)
1355 {
1356         unsigned int idx = offset / 8;
1357         unsigned int bit_nr = 0;
1358         unsigned int bit_shift = offset % 8;
1359         int bits_to_copy = 8 - bit_shift;
1360         u32 value = 0;
1361         u32 mask = n < 32 ? (1U << n) - 1 : ~0U;
1362
1363         while (n > 0) {
1364                 value |= ((u32)report[idx] >> bit_shift) << bit_nr;
1365                 n -= bits_to_copy;
1366                 bit_nr += bits_to_copy;
1367                 bits_to_copy = 8;
1368                 bit_shift = 0;
1369                 idx++;
1370         }
1371
1372         return value & mask;
1373 }
1374
1375 u32 hid_field_extract(const struct hid_device *hid, u8 *report,
1376                         unsigned offset, unsigned n)
1377 {
1378         if (n > 32) {
1379                 hid_warn_once(hid, "%s() called with n (%d) > 32! (%s)\n",
1380                               __func__, n, current->comm);
1381                 n = 32;
1382         }
1383
1384         return __extract(report, offset, n);
1385 }
1386 EXPORT_SYMBOL_GPL(hid_field_extract);
1387
1388 /*
1389  * "implement" : set bits in a little endian bit stream.
1390  * Same concepts as "extract" (see comments above).
1391  * The data mangled in the bit stream remains in little endian
1392  * order the whole time. It make more sense to talk about
1393  * endianness of register values by considering a register
1394  * a "cached" copy of the little endian bit stream.
1395  */
1396
1397 static void __implement(u8 *report, unsigned offset, int n, u32 value)
1398 {
1399         unsigned int idx = offset / 8;
1400         unsigned int bit_shift = offset % 8;
1401         int bits_to_set = 8 - bit_shift;
1402
1403         while (n - bits_to_set >= 0) {
1404                 report[idx] &= ~(0xff << bit_shift);
1405                 report[idx] |= value << bit_shift;
1406                 value >>= bits_to_set;
1407                 n -= bits_to_set;
1408                 bits_to_set = 8;
1409                 bit_shift = 0;
1410                 idx++;
1411         }
1412
1413         /* last nibble */
1414         if (n) {
1415                 u8 bit_mask = ((1U << n) - 1);
1416                 report[idx] &= ~(bit_mask << bit_shift);
1417                 report[idx] |= value << bit_shift;
1418         }
1419 }
1420
1421 static void implement(const struct hid_device *hid, u8 *report,
1422                       unsigned offset, unsigned n, u32 value)
1423 {
1424         if (unlikely(n > 32)) {
1425                 hid_warn(hid, "%s() called with n (%d) > 32! (%s)\n",
1426                          __func__, n, current->comm);
1427                 n = 32;
1428         } else if (n < 32) {
1429                 u32 m = (1U << n) - 1;
1430
1431                 if (unlikely(value > m)) {
1432                         hid_warn(hid,
1433                                  "%s() called with too large value %d (n: %d)! (%s)\n",
1434                                  __func__, value, n, current->comm);
1435                         WARN_ON(1);
1436                         value &= m;
1437                 }
1438         }
1439
1440         __implement(report, offset, n, value);
1441 }
1442
1443 /*
1444  * Search an array for a value.
1445  */
1446
1447 static int search(__s32 *array, __s32 value, unsigned n)
1448 {
1449         while (n--) {
1450                 if (*array++ == value)
1451                         return 0;
1452         }
1453         return -1;
1454 }
1455
1456 /**
1457  * hid_match_report - check if driver's raw_event should be called
1458  *
1459  * @hid: hid device
1460  * @report_type: type to match against
1461  *
1462  * compare hid->driver->report_table->report_type to report->type
1463  */
1464 static int hid_match_report(struct hid_device *hid, struct hid_report *report)
1465 {
1466         const struct hid_report_id *id = hid->driver->report_table;
1467
1468         if (!id) /* NULL means all */
1469                 return 1;
1470
1471         for (; id->report_type != HID_TERMINATOR; id++)
1472                 if (id->report_type == HID_ANY_ID ||
1473                                 id->report_type == report->type)
1474                         return 1;
1475         return 0;
1476 }
1477
1478 /**
1479  * hid_match_usage - check if driver's event should be called
1480  *
1481  * @hid: hid device
1482  * @usage: usage to match against
1483  *
1484  * compare hid->driver->usage_table->usage_{type,code} to
1485  * usage->usage_{type,code}
1486  */
1487 static int hid_match_usage(struct hid_device *hid, struct hid_usage *usage)
1488 {
1489         const struct hid_usage_id *id = hid->driver->usage_table;
1490
1491         if (!id) /* NULL means all */
1492                 return 1;
1493
1494         for (; id->usage_type != HID_ANY_ID - 1; id++)
1495                 if ((id->usage_hid == HID_ANY_ID ||
1496                                 id->usage_hid == usage->hid) &&
1497                                 (id->usage_type == HID_ANY_ID ||
1498                                 id->usage_type == usage->type) &&
1499                                 (id->usage_code == HID_ANY_ID ||
1500                                  id->usage_code == usage->code))
1501                         return 1;
1502         return 0;
1503 }
1504
1505 static void hid_process_event(struct hid_device *hid, struct hid_field *field,
1506                 struct hid_usage *usage, __s32 value, int interrupt)
1507 {
1508         struct hid_driver *hdrv = hid->driver;
1509         int ret;
1510
1511         if (!list_empty(&hid->debug_list))
1512                 hid_dump_input(hid, usage, value);
1513
1514         if (hdrv && hdrv->event && hid_match_usage(hid, usage)) {
1515                 ret = hdrv->event(hid, field, usage, value);
1516                 if (ret != 0) {
1517                         if (ret < 0)
1518                                 hid_err(hid, "%s's event failed with %d\n",
1519                                                 hdrv->name, ret);
1520                         return;
1521                 }
1522         }
1523
1524         if (hid->claimed & HID_CLAIMED_INPUT)
1525                 hidinput_hid_event(hid, field, usage, value);
1526         if (hid->claimed & HID_CLAIMED_HIDDEV && interrupt && hid->hiddev_hid_event)
1527                 hid->hiddev_hid_event(hid, field, usage, value);
1528 }
1529
1530 /*
1531  * Analyse a received field, and fetch the data from it. The field
1532  * content is stored for next report processing (we do differential
1533  * reporting to the layer).
1534  */
1535
1536 static void hid_input_field(struct hid_device *hid, struct hid_field *field,
1537                             __u8 *data, int interrupt)
1538 {
1539         unsigned n;
1540         unsigned count = field->report_count;
1541         unsigned offset = field->report_offset;
1542         unsigned size = field->report_size;
1543         __s32 min = field->logical_minimum;
1544         __s32 max = field->logical_maximum;
1545         __s32 *value;
1546
1547         value = kmalloc_array(count, sizeof(__s32), GFP_ATOMIC);
1548         if (!value)
1549                 return;
1550
1551         for (n = 0; n < count; n++) {
1552
1553                 value[n] = min < 0 ?
1554                         snto32(hid_field_extract(hid, data, offset + n * size,
1555                                size), size) :
1556                         hid_field_extract(hid, data, offset + n * size, size);
1557
1558                 /* Ignore report if ErrorRollOver */
1559                 if (!(field->flags & HID_MAIN_ITEM_VARIABLE) &&
1560                     value[n] >= min && value[n] <= max &&
1561                     value[n] - min < field->maxusage &&
1562                     field->usage[value[n] - min].hid == HID_UP_KEYBOARD + 1)
1563                         goto exit;
1564         }
1565
1566         for (n = 0; n < count; n++) {
1567
1568                 if (HID_MAIN_ITEM_VARIABLE & field->flags) {
1569                         hid_process_event(hid, field, &field->usage[n], value[n], interrupt);
1570                         continue;
1571                 }
1572
1573                 if (field->value[n] >= min && field->value[n] <= max
1574                         && field->value[n] - min < field->maxusage
1575                         && field->usage[field->value[n] - min].hid
1576                         && search(value, field->value[n], count))
1577                                 hid_process_event(hid, field, &field->usage[field->value[n] - min], 0, interrupt);
1578
1579                 if (value[n] >= min && value[n] <= max
1580                         && value[n] - min < field->maxusage
1581                         && field->usage[value[n] - min].hid
1582                         && search(field->value, value[n], count))
1583                                 hid_process_event(hid, field, &field->usage[value[n] - min], 1, interrupt);
1584         }
1585
1586         memcpy(field->value, value, count * sizeof(__s32));
1587 exit:
1588         kfree(value);
1589 }
1590
1591 /*
1592  * Output the field into the report.
1593  */
1594
1595 static void hid_output_field(const struct hid_device *hid,
1596                              struct hid_field *field, __u8 *data)
1597 {
1598         unsigned count = field->report_count;
1599         unsigned offset = field->report_offset;
1600         unsigned size = field->report_size;
1601         unsigned n;
1602
1603         for (n = 0; n < count; n++) {
1604                 if (field->logical_minimum < 0) /* signed values */
1605                         implement(hid, data, offset + n * size, size,
1606                                   s32ton(field->value[n], size));
1607                 else                            /* unsigned values */
1608                         implement(hid, data, offset + n * size, size,
1609                                   field->value[n]);
1610         }
1611 }
1612
1613 /*
1614  * Compute the size of a report.
1615  */
1616 static size_t hid_compute_report_size(struct hid_report *report)
1617 {
1618         if (report->size)
1619                 return ((report->size - 1) >> 3) + 1;
1620
1621         return 0;
1622 }
1623
1624 /*
1625  * Create a report. 'data' has to be allocated using
1626  * hid_alloc_report_buf() so that it has proper size.
1627  */
1628
1629 void hid_output_report(struct hid_report *report, __u8 *data)
1630 {
1631         unsigned n;
1632
1633         if (report->id > 0)
1634                 *data++ = report->id;
1635
1636         memset(data, 0, hid_compute_report_size(report));
1637         for (n = 0; n < report->maxfield; n++)
1638                 hid_output_field(report->device, report->field[n], data);
1639 }
1640 EXPORT_SYMBOL_GPL(hid_output_report);
1641
1642 /*
1643  * Allocator for buffer that is going to be passed to hid_output_report()
1644  */
1645 u8 *hid_alloc_report_buf(struct hid_report *report, gfp_t flags)
1646 {
1647         /*
1648          * 7 extra bytes are necessary to achieve proper functionality
1649          * of implement() working on 8 byte chunks
1650          */
1651
1652         u32 len = hid_report_len(report) + 7;
1653
1654         return kmalloc(len, flags);
1655 }
1656 EXPORT_SYMBOL_GPL(hid_alloc_report_buf);
1657
1658 /*
1659  * Set a field value. The report this field belongs to has to be
1660  * created and transferred to the device, to set this value in the
1661  * device.
1662  */
1663
1664 int hid_set_field(struct hid_field *field, unsigned offset, __s32 value)
1665 {
1666         unsigned size;
1667
1668         if (!field)
1669                 return -1;
1670
1671         size = field->report_size;
1672
1673         hid_dump_input(field->report->device, field->usage + offset, value);
1674
1675         if (offset >= field->report_count) {
1676                 hid_err(field->report->device, "offset (%d) exceeds report_count (%d)\n",
1677                                 offset, field->report_count);
1678                 return -1;
1679         }
1680         if (field->logical_minimum < 0) {
1681                 if (value != snto32(s32ton(value, size), size)) {
1682                         hid_err(field->report->device, "value %d is out of range\n", value);
1683                         return -1;
1684                 }
1685         }
1686         field->value[offset] = value;
1687         return 0;
1688 }
1689 EXPORT_SYMBOL_GPL(hid_set_field);
1690
1691 static struct hid_report *hid_get_report(struct hid_report_enum *report_enum,
1692                 const u8 *data)
1693 {
1694         struct hid_report *report;
1695         unsigned int n = 0;     /* Normally report number is 0 */
1696
1697         /* Device uses numbered reports, data[0] is report number */
1698         if (report_enum->numbered)
1699                 n = *data;
1700
1701         report = report_enum->report_id_hash[n];
1702         if (report == NULL)
1703                 dbg_hid("undefined report_id %u received\n", n);
1704
1705         return report;
1706 }
1707
1708 /*
1709  * Implement a generic .request() callback, using .raw_request()
1710  * DO NOT USE in hid drivers directly, but through hid_hw_request instead.
1711  */
1712 int __hid_request(struct hid_device *hid, struct hid_report *report,
1713                 int reqtype)
1714 {
1715         char *buf;
1716         int ret;
1717         u32 len;
1718
1719         buf = hid_alloc_report_buf(report, GFP_KERNEL);
1720         if (!buf)
1721                 return -ENOMEM;
1722
1723         len = hid_report_len(report);
1724
1725         if (reqtype == HID_REQ_SET_REPORT)
1726                 hid_output_report(report, buf);
1727
1728         ret = hid->ll_driver->raw_request(hid, report->id, buf, len,
1729                                           report->type, reqtype);
1730         if (ret < 0) {
1731                 dbg_hid("unable to complete request: %d\n", ret);
1732                 goto out;
1733         }
1734
1735         if (reqtype == HID_REQ_GET_REPORT)
1736                 hid_input_report(hid, report->type, buf, ret, 0);
1737
1738         ret = 0;
1739
1740 out:
1741         kfree(buf);
1742         return ret;
1743 }
1744 EXPORT_SYMBOL_GPL(__hid_request);
1745
1746 int hid_report_raw_event(struct hid_device *hid, int type, u8 *data, u32 size,
1747                 int interrupt)
1748 {
1749         struct hid_report_enum *report_enum = hid->report_enum + type;
1750         struct hid_report *report;
1751         struct hid_driver *hdrv;
1752         int max_buffer_size = HID_MAX_BUFFER_SIZE;
1753         unsigned int a;
1754         u32 rsize, csize = size;
1755         u8 *cdata = data;
1756         int ret = 0;
1757
1758         report = hid_get_report(report_enum, data);
1759         if (!report)
1760                 goto out;
1761
1762         if (report_enum->numbered) {
1763                 cdata++;
1764                 csize--;
1765         }
1766
1767         rsize = hid_compute_report_size(report);
1768
1769         if (hid->ll_driver->max_buffer_size)
1770                 max_buffer_size = hid->ll_driver->max_buffer_size;
1771
1772         if (report_enum->numbered && rsize >= max_buffer_size)
1773                 rsize = max_buffer_size - 1;
1774         else if (rsize > max_buffer_size)
1775                 rsize = max_buffer_size;
1776
1777         if (csize < rsize) {
1778                 dbg_hid("report %d is too short, (%d < %d)\n", report->id,
1779                                 csize, rsize);
1780                 memset(cdata + csize, 0, rsize - csize);
1781         }
1782
1783         if ((hid->claimed & HID_CLAIMED_HIDDEV) && hid->hiddev_report_event)
1784                 hid->hiddev_report_event(hid, report);
1785         if (hid->claimed & HID_CLAIMED_HIDRAW) {
1786                 ret = hidraw_report_event(hid, data, size);
1787                 if (ret)
1788                         goto out;
1789         }
1790
1791         if (hid->claimed != HID_CLAIMED_HIDRAW && report->maxfield) {
1792                 for (a = 0; a < report->maxfield; a++)
1793                         hid_input_field(hid, report->field[a], cdata, interrupt);
1794                 hdrv = hid->driver;
1795                 if (hdrv && hdrv->report)
1796                         hdrv->report(hid, report);
1797         }
1798
1799         if (hid->claimed & HID_CLAIMED_INPUT)
1800                 hidinput_report_event(hid, report);
1801 out:
1802         return ret;
1803 }
1804 EXPORT_SYMBOL_GPL(hid_report_raw_event);
1805
1806 /**
1807  * hid_input_report - report data from lower layer (usb, bt...)
1808  *
1809  * @hid: hid device
1810  * @type: HID report type (HID_*_REPORT)
1811  * @data: report contents
1812  * @size: size of data parameter
1813  * @interrupt: distinguish between interrupt and control transfers
1814  *
1815  * This is data entry for lower layers.
1816  */
1817 int hid_input_report(struct hid_device *hid, int type, u8 *data, u32 size, int interrupt)
1818 {
1819         struct hid_report_enum *report_enum;
1820         struct hid_driver *hdrv;
1821         struct hid_report *report;
1822         int ret = 0;
1823
1824         if (!hid)
1825                 return -ENODEV;
1826
1827         if (down_trylock(&hid->driver_input_lock))
1828                 return -EBUSY;
1829
1830         if (!hid->driver) {
1831                 ret = -ENODEV;
1832                 goto unlock;
1833         }
1834         report_enum = hid->report_enum + type;
1835         hdrv = hid->driver;
1836
1837         if (!size) {
1838                 dbg_hid("empty report\n");
1839                 ret = -1;
1840                 goto unlock;
1841         }
1842
1843         /* Avoid unnecessary overhead if debugfs is disabled */
1844         if (!list_empty(&hid->debug_list))
1845                 hid_dump_report(hid, type, data, size);
1846
1847         report = hid_get_report(report_enum, data);
1848
1849         if (!report) {
1850                 ret = -1;
1851                 goto unlock;
1852         }
1853
1854         if (hdrv && hdrv->raw_event && hid_match_report(hid, report)) {
1855                 ret = hdrv->raw_event(hid, report, data, size);
1856                 if (ret < 0)
1857                         goto unlock;
1858         }
1859
1860         ret = hid_report_raw_event(hid, type, data, size, interrupt);
1861
1862 unlock:
1863         up(&hid->driver_input_lock);
1864         return ret;
1865 }
1866 EXPORT_SYMBOL_GPL(hid_input_report);
1867
1868 bool hid_match_one_id(const struct hid_device *hdev,
1869                       const struct hid_device_id *id)
1870 {
1871         return (id->bus == HID_BUS_ANY || id->bus == hdev->bus) &&
1872                 (id->group == HID_GROUP_ANY || id->group == hdev->group) &&
1873                 (id->vendor == HID_ANY_ID || id->vendor == hdev->vendor) &&
1874                 (id->product == HID_ANY_ID || id->product == hdev->product);
1875 }
1876
1877 const struct hid_device_id *hid_match_id(const struct hid_device *hdev,
1878                 const struct hid_device_id *id)
1879 {
1880         for (; id->bus; id++)
1881                 if (hid_match_one_id(hdev, id))
1882                         return id;
1883
1884         return NULL;
1885 }
1886
1887 static const struct hid_device_id hid_hiddev_list[] = {
1888         { HID_USB_DEVICE(USB_VENDOR_ID_MGE, USB_DEVICE_ID_MGE_UPS) },
1889         { HID_USB_DEVICE(USB_VENDOR_ID_MGE, USB_DEVICE_ID_MGE_UPS1) },
1890         { }
1891 };
1892
1893 static bool hid_hiddev(struct hid_device *hdev)
1894 {
1895         return !!hid_match_id(hdev, hid_hiddev_list);
1896 }
1897
1898
1899 static ssize_t
1900 read_report_descriptor(struct file *filp, struct kobject *kobj,
1901                 struct bin_attribute *attr,
1902                 char *buf, loff_t off, size_t count)
1903 {
1904         struct device *dev = kobj_to_dev(kobj);
1905         struct hid_device *hdev = to_hid_device(dev);
1906
1907         if (off >= hdev->rsize)
1908                 return 0;
1909
1910         if (off + count > hdev->rsize)
1911                 count = hdev->rsize - off;
1912
1913         memcpy(buf, hdev->rdesc + off, count);
1914
1915         return count;
1916 }
1917
1918 static ssize_t
1919 show_country(struct device *dev, struct device_attribute *attr,
1920                 char *buf)
1921 {
1922         struct hid_device *hdev = to_hid_device(dev);
1923
1924         return sprintf(buf, "%02x\n", hdev->country & 0xff);
1925 }
1926
1927 static struct bin_attribute dev_bin_attr_report_desc = {
1928         .attr = { .name = "report_descriptor", .mode = 0444 },
1929         .read = read_report_descriptor,
1930         .size = HID_MAX_DESCRIPTOR_SIZE,
1931 };
1932
1933 static const struct device_attribute dev_attr_country = {
1934         .attr = { .name = "country", .mode = 0444 },
1935         .show = show_country,
1936 };
1937
1938 int hid_connect(struct hid_device *hdev, unsigned int connect_mask)
1939 {
1940         static const char *types[] = { "Device", "Pointer", "Mouse", "Device",
1941                 "Joystick", "Gamepad", "Keyboard", "Keypad",
1942                 "Multi-Axis Controller"
1943         };
1944         const char *type, *bus;
1945         char buf[64] = "";
1946         unsigned int i;
1947         int len;
1948         int ret;
1949
1950         if (hdev->quirks & HID_QUIRK_HIDDEV_FORCE)
1951                 connect_mask |= (HID_CONNECT_HIDDEV_FORCE | HID_CONNECT_HIDDEV);
1952         if (hdev->quirks & HID_QUIRK_HIDINPUT_FORCE)
1953                 connect_mask |= HID_CONNECT_HIDINPUT_FORCE;
1954         if (hdev->bus != BUS_USB)
1955                 connect_mask &= ~HID_CONNECT_HIDDEV;
1956         if (hid_hiddev(hdev))
1957                 connect_mask |= HID_CONNECT_HIDDEV_FORCE;
1958
1959         if ((connect_mask & HID_CONNECT_HIDINPUT) && !hidinput_connect(hdev,
1960                                 connect_mask & HID_CONNECT_HIDINPUT_FORCE))
1961                 hdev->claimed |= HID_CLAIMED_INPUT;
1962
1963         if ((connect_mask & HID_CONNECT_HIDDEV) && hdev->hiddev_connect &&
1964                         !hdev->hiddev_connect(hdev,
1965                                 connect_mask & HID_CONNECT_HIDDEV_FORCE))
1966                 hdev->claimed |= HID_CLAIMED_HIDDEV;
1967         if ((connect_mask & HID_CONNECT_HIDRAW) && !hidraw_connect(hdev))
1968                 hdev->claimed |= HID_CLAIMED_HIDRAW;
1969
1970         if (connect_mask & HID_CONNECT_DRIVER)
1971                 hdev->claimed |= HID_CLAIMED_DRIVER;
1972
1973         /* Drivers with the ->raw_event callback set are not required to connect
1974          * to any other listener. */
1975         if (!hdev->claimed && !hdev->driver->raw_event) {
1976                 hid_err(hdev, "device has no listeners, quitting\n");
1977                 return -ENODEV;
1978         }
1979
1980         if ((hdev->claimed & HID_CLAIMED_INPUT) &&
1981                         (connect_mask & HID_CONNECT_FF) && hdev->ff_init)
1982                 hdev->ff_init(hdev);
1983
1984         len = 0;
1985         if (hdev->claimed & HID_CLAIMED_INPUT)
1986                 len += sprintf(buf + len, "input");
1987         if (hdev->claimed & HID_CLAIMED_HIDDEV)
1988                 len += sprintf(buf + len, "%shiddev%d", len ? "," : "",
1989                                 ((struct hiddev *)hdev->hiddev)->minor);
1990         if (hdev->claimed & HID_CLAIMED_HIDRAW)
1991                 len += sprintf(buf + len, "%shidraw%d", len ? "," : "",
1992                                 ((struct hidraw *)hdev->hidraw)->minor);
1993
1994         type = "Device";
1995         for (i = 0; i < hdev->maxcollection; i++) {
1996                 struct hid_collection *col = &hdev->collection[i];
1997                 if (col->type == HID_COLLECTION_APPLICATION &&
1998                    (col->usage & HID_USAGE_PAGE) == HID_UP_GENDESK &&
1999                    (col->usage & 0xffff) < ARRAY_SIZE(types)) {
2000                         type = types[col->usage & 0xffff];
2001                         break;
2002                 }
2003         }
2004
2005         switch (hdev->bus) {
2006         case BUS_USB:
2007                 bus = "USB";
2008                 break;
2009         case BUS_BLUETOOTH:
2010                 bus = "BLUETOOTH";
2011                 break;
2012         case BUS_I2C:
2013                 bus = "I2C";
2014                 break;
2015         case BUS_VIRTUAL:
2016                 bus = "VIRTUAL";
2017                 break;
2018         default:
2019                 bus = "<UNKNOWN>";
2020         }
2021
2022         ret = device_create_file(&hdev->dev, &dev_attr_country);
2023         if (ret)
2024                 hid_warn(hdev,
2025                          "can't create sysfs country code attribute err: %d\n", ret);
2026
2027         hid_info(hdev, "%s: %s HID v%x.%02x %s [%s] on %s\n",
2028                  buf, bus, hdev->version >> 8, hdev->version & 0xff,
2029                  type, hdev->name, hdev->phys);
2030
2031         return 0;
2032 }
2033 EXPORT_SYMBOL_GPL(hid_connect);
2034
2035 void hid_disconnect(struct hid_device *hdev)
2036 {
2037         device_remove_file(&hdev->dev, &dev_attr_country);
2038         if (hdev->claimed & HID_CLAIMED_INPUT)
2039                 hidinput_disconnect(hdev);
2040         if (hdev->claimed & HID_CLAIMED_HIDDEV)
2041                 hdev->hiddev_disconnect(hdev);
2042         if (hdev->claimed & HID_CLAIMED_HIDRAW)
2043                 hidraw_disconnect(hdev);
2044         hdev->claimed = 0;
2045 }
2046 EXPORT_SYMBOL_GPL(hid_disconnect);
2047
2048 /**
2049  * hid_hw_start - start underlying HW
2050  * @hdev: hid device
2051  * @connect_mask: which outputs to connect, see HID_CONNECT_*
2052  *
2053  * Call this in probe function *after* hid_parse. This will setup HW
2054  * buffers and start the device (if not defeirred to device open).
2055  * hid_hw_stop must be called if this was successful.
2056  */
2057 int hid_hw_start(struct hid_device *hdev, unsigned int connect_mask)
2058 {
2059         int error;
2060
2061         error = hdev->ll_driver->start(hdev);
2062         if (error)
2063                 return error;
2064
2065         if (connect_mask) {
2066                 error = hid_connect(hdev, connect_mask);
2067                 if (error) {
2068                         hdev->ll_driver->stop(hdev);
2069                         return error;
2070                 }
2071         }
2072
2073         return 0;
2074 }
2075 EXPORT_SYMBOL_GPL(hid_hw_start);
2076
2077 /**
2078  * hid_hw_stop - stop underlying HW
2079  * @hdev: hid device
2080  *
2081  * This is usually called from remove function or from probe when something
2082  * failed and hid_hw_start was called already.
2083  */
2084 void hid_hw_stop(struct hid_device *hdev)
2085 {
2086         hid_disconnect(hdev);
2087         hdev->ll_driver->stop(hdev);
2088 }
2089 EXPORT_SYMBOL_GPL(hid_hw_stop);
2090
2091 /**
2092  * hid_hw_open - signal underlying HW to start delivering events
2093  * @hdev: hid device
2094  *
2095  * Tell underlying HW to start delivering events from the device.
2096  * This function should be called sometime after successful call
2097  * to hid_hw_start().
2098  */
2099 int hid_hw_open(struct hid_device *hdev)
2100 {
2101         int ret;
2102
2103         ret = mutex_lock_killable(&hdev->ll_open_lock);
2104         if (ret)
2105                 return ret;
2106
2107         if (!hdev->ll_open_count++) {
2108                 ret = hdev->ll_driver->open(hdev);
2109                 if (ret)
2110                         hdev->ll_open_count--;
2111         }
2112
2113         mutex_unlock(&hdev->ll_open_lock);
2114         return ret;
2115 }
2116 EXPORT_SYMBOL_GPL(hid_hw_open);
2117
2118 /**
2119  * hid_hw_close - signal underlaying HW to stop delivering events
2120  *
2121  * @hdev: hid device
2122  *
2123  * This function indicates that we are not interested in the events
2124  * from this device anymore. Delivery of events may or may not stop,
2125  * depending on the number of users still outstanding.
2126  */
2127 void hid_hw_close(struct hid_device *hdev)
2128 {
2129         mutex_lock(&hdev->ll_open_lock);
2130         if (!--hdev->ll_open_count)
2131                 hdev->ll_driver->close(hdev);
2132         mutex_unlock(&hdev->ll_open_lock);
2133 }
2134 EXPORT_SYMBOL_GPL(hid_hw_close);
2135
2136 struct hid_dynid {
2137         struct list_head list;
2138         struct hid_device_id id;
2139 };
2140
2141 /**
2142  * store_new_id - add a new HID device ID to this driver and re-probe devices
2143  * @driver: target device driver
2144  * @buf: buffer for scanning device ID data
2145  * @count: input size
2146  *
2147  * Adds a new dynamic hid device ID to this driver,
2148  * and causes the driver to probe for all devices again.
2149  */
2150 static ssize_t new_id_store(struct device_driver *drv, const char *buf,
2151                 size_t count)
2152 {
2153         struct hid_driver *hdrv = to_hid_driver(drv);
2154         struct hid_dynid *dynid;
2155         __u32 bus, vendor, product;
2156         unsigned long driver_data = 0;
2157         int ret;
2158
2159         ret = sscanf(buf, "%x %x %x %lx",
2160                         &bus, &vendor, &product, &driver_data);
2161         if (ret < 3)
2162                 return -EINVAL;
2163
2164         dynid = kzalloc(sizeof(*dynid), GFP_KERNEL);
2165         if (!dynid)
2166                 return -ENOMEM;
2167
2168         dynid->id.bus = bus;
2169         dynid->id.group = HID_GROUP_ANY;
2170         dynid->id.vendor = vendor;
2171         dynid->id.product = product;
2172         dynid->id.driver_data = driver_data;
2173
2174         spin_lock(&hdrv->dyn_lock);
2175         list_add_tail(&dynid->list, &hdrv->dyn_list);
2176         spin_unlock(&hdrv->dyn_lock);
2177
2178         ret = driver_attach(&hdrv->driver);
2179
2180         return ret ? : count;
2181 }
2182 static DRIVER_ATTR_WO(new_id);
2183
2184 static struct attribute *hid_drv_attrs[] = {
2185         &driver_attr_new_id.attr,
2186         NULL,
2187 };
2188 ATTRIBUTE_GROUPS(hid_drv);
2189
2190 static void hid_free_dynids(struct hid_driver *hdrv)
2191 {
2192         struct hid_dynid *dynid, *n;
2193
2194         spin_lock(&hdrv->dyn_lock);
2195         list_for_each_entry_safe(dynid, n, &hdrv->dyn_list, list) {
2196                 list_del(&dynid->list);
2197                 kfree(dynid);
2198         }
2199         spin_unlock(&hdrv->dyn_lock);
2200 }
2201
2202 const struct hid_device_id *hid_match_device(struct hid_device *hdev,
2203                                              struct hid_driver *hdrv)
2204 {
2205         struct hid_dynid *dynid;
2206
2207         spin_lock(&hdrv->dyn_lock);
2208         list_for_each_entry(dynid, &hdrv->dyn_list, list) {
2209                 if (hid_match_one_id(hdev, &dynid->id)) {
2210                         spin_unlock(&hdrv->dyn_lock);
2211                         return &dynid->id;
2212                 }
2213         }
2214         spin_unlock(&hdrv->dyn_lock);
2215
2216         return hid_match_id(hdev, hdrv->id_table);
2217 }
2218 EXPORT_SYMBOL_GPL(hid_match_device);
2219
2220 static int hid_bus_match(struct device *dev, struct device_driver *drv)
2221 {
2222         struct hid_driver *hdrv = to_hid_driver(drv);
2223         struct hid_device *hdev = to_hid_device(dev);
2224
2225         return hid_match_device(hdev, hdrv) != NULL;
2226 }
2227
2228 /**
2229  * hid_compare_device_paths - check if both devices share the same path
2230  * @hdev_a: hid device
2231  * @hdev_b: hid device
2232  * @separator: char to use as separator
2233  *
2234  * Check if two devices share the same path up to the last occurrence of
2235  * the separator char. Both paths must exist (i.e., zero-length paths
2236  * don't match).
2237  */
2238 bool hid_compare_device_paths(struct hid_device *hdev_a,
2239                               struct hid_device *hdev_b, char separator)
2240 {
2241         int n1 = strrchr(hdev_a->phys, separator) - hdev_a->phys;
2242         int n2 = strrchr(hdev_b->phys, separator) - hdev_b->phys;
2243
2244         if (n1 != n2 || n1 <= 0 || n2 <= 0)
2245                 return false;
2246
2247         return !strncmp(hdev_a->phys, hdev_b->phys, n1);
2248 }
2249 EXPORT_SYMBOL_GPL(hid_compare_device_paths);
2250
2251 static int hid_device_probe(struct device *dev)
2252 {
2253         struct hid_driver *hdrv = to_hid_driver(dev->driver);
2254         struct hid_device *hdev = to_hid_device(dev);
2255         const struct hid_device_id *id;
2256         int ret = 0;
2257
2258         if (down_interruptible(&hdev->driver_input_lock)) {
2259                 ret = -EINTR;
2260                 goto end;
2261         }
2262         hdev->io_started = false;
2263
2264         clear_bit(ffs(HID_STAT_REPROBED), &hdev->status);
2265
2266         if (!hdev->driver) {
2267                 id = hid_match_device(hdev, hdrv);
2268                 if (id == NULL) {
2269                         ret = -ENODEV;
2270                         goto unlock;
2271                 }
2272
2273                 if (hdrv->match) {
2274                         if (!hdrv->match(hdev, hid_ignore_special_drivers)) {
2275                                 ret = -ENODEV;
2276                                 goto unlock;
2277                         }
2278                 } else {
2279                         /*
2280                          * hid-generic implements .match(), so if
2281                          * hid_ignore_special_drivers is set, we can safely
2282                          * return.
2283                          */
2284                         if (hid_ignore_special_drivers) {
2285                                 ret = -ENODEV;
2286                                 goto unlock;
2287                         }
2288                 }
2289
2290                 /* reset the quirks that has been previously set */
2291                 hdev->quirks = hid_lookup_quirk(hdev);
2292                 hdev->driver = hdrv;
2293                 if (hdrv->probe) {
2294                         ret = hdrv->probe(hdev, id);
2295                 } else { /* default probe */
2296                         ret = hid_open_report(hdev);
2297                         if (!ret)
2298                                 ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
2299                 }
2300                 if (ret) {
2301                         hid_close_report(hdev);
2302                         hdev->driver = NULL;
2303                 }
2304         }
2305 unlock:
2306         if (!hdev->io_started)
2307                 up(&hdev->driver_input_lock);
2308 end:
2309         return ret;
2310 }
2311
2312 static int hid_device_remove(struct device *dev)
2313 {
2314         struct hid_device *hdev = to_hid_device(dev);
2315         struct hid_driver *hdrv;
2316
2317         down(&hdev->driver_input_lock);
2318         hdev->io_started = false;
2319
2320         hdrv = hdev->driver;
2321         if (hdrv) {
2322                 if (hdrv->remove)
2323                         hdrv->remove(hdev);
2324                 else /* default remove */
2325                         hid_hw_stop(hdev);
2326                 hid_close_report(hdev);
2327                 hdev->driver = NULL;
2328         }
2329
2330         if (!hdev->io_started)
2331                 up(&hdev->driver_input_lock);
2332
2333         return 0;
2334 }
2335
2336 static ssize_t modalias_show(struct device *dev, struct device_attribute *a,
2337                              char *buf)
2338 {
2339         struct hid_device *hdev = container_of(dev, struct hid_device, dev);
2340
2341         return scnprintf(buf, PAGE_SIZE, "hid:b%04Xg%04Xv%08Xp%08X\n",
2342                          hdev->bus, hdev->group, hdev->vendor, hdev->product);
2343 }
2344 static DEVICE_ATTR_RO(modalias);
2345
2346 static struct attribute *hid_dev_attrs[] = {
2347         &dev_attr_modalias.attr,
2348         NULL,
2349 };
2350 static struct bin_attribute *hid_dev_bin_attrs[] = {
2351         &dev_bin_attr_report_desc,
2352         NULL
2353 };
2354 static const struct attribute_group hid_dev_group = {
2355         .attrs = hid_dev_attrs,
2356         .bin_attrs = hid_dev_bin_attrs,
2357 };
2358 __ATTRIBUTE_GROUPS(hid_dev);
2359
2360 static int hid_uevent(struct device *dev, struct kobj_uevent_env *env)
2361 {
2362         struct hid_device *hdev = to_hid_device(dev);
2363
2364         if (add_uevent_var(env, "HID_ID=%04X:%08X:%08X",
2365                         hdev->bus, hdev->vendor, hdev->product))
2366                 return -ENOMEM;
2367
2368         if (add_uevent_var(env, "HID_NAME=%s", hdev->name))
2369                 return -ENOMEM;
2370
2371         if (add_uevent_var(env, "HID_PHYS=%s", hdev->phys))
2372                 return -ENOMEM;
2373
2374         if (add_uevent_var(env, "HID_UNIQ=%s", hdev->uniq))
2375                 return -ENOMEM;
2376
2377         if (add_uevent_var(env, "MODALIAS=hid:b%04Xg%04Xv%08Xp%08X",
2378                            hdev->bus, hdev->group, hdev->vendor, hdev->product))
2379                 return -ENOMEM;
2380
2381         return 0;
2382 }
2383
2384 struct bus_type hid_bus_type = {
2385         .name           = "hid",
2386         .dev_groups     = hid_dev_groups,
2387         .drv_groups     = hid_drv_groups,
2388         .match          = hid_bus_match,
2389         .probe          = hid_device_probe,
2390         .remove         = hid_device_remove,
2391         .uevent         = hid_uevent,
2392 };
2393 EXPORT_SYMBOL(hid_bus_type);
2394
2395 int hid_add_device(struct hid_device *hdev)
2396 {
2397         static atomic_t id = ATOMIC_INIT(0);
2398         int ret;
2399
2400         if (WARN_ON(hdev->status & HID_STAT_ADDED))
2401                 return -EBUSY;
2402
2403         hdev->quirks = hid_lookup_quirk(hdev);
2404
2405         /* we need to kill them here, otherwise they will stay allocated to
2406          * wait for coming driver */
2407         if (hid_ignore(hdev))
2408                 return -ENODEV;
2409
2410         /*
2411          * Check for the mandatory transport channel.
2412          */
2413          if (!hdev->ll_driver->raw_request) {
2414                 hid_err(hdev, "transport driver missing .raw_request()\n");
2415                 return -EINVAL;
2416          }
2417
2418         /*
2419          * Read the device report descriptor once and use as template
2420          * for the driver-specific modifications.
2421          */
2422         ret = hdev->ll_driver->parse(hdev);
2423         if (ret)
2424                 return ret;
2425         if (!hdev->dev_rdesc)
2426                 return -ENODEV;
2427
2428         /*
2429          * Scan generic devices for group information
2430          */
2431         if (hid_ignore_special_drivers) {
2432                 hdev->group = HID_GROUP_GENERIC;
2433         } else if (!hdev->group &&
2434                    !(hdev->quirks & HID_QUIRK_HAVE_SPECIAL_DRIVER)) {
2435                 ret = hid_scan_report(hdev);
2436                 if (ret)
2437                         hid_warn(hdev, "bad device descriptor (%d)\n", ret);
2438         }
2439
2440         /* XXX hack, any other cleaner solution after the driver core
2441          * is converted to allow more than 20 bytes as the device name? */
2442         dev_set_name(&hdev->dev, "%04X:%04X:%04X.%04X", hdev->bus,
2443                      hdev->vendor, hdev->product, atomic_inc_return(&id));
2444
2445         hid_debug_register(hdev, dev_name(&hdev->dev));
2446         ret = device_add(&hdev->dev);
2447         if (!ret)
2448                 hdev->status |= HID_STAT_ADDED;
2449         else
2450                 hid_debug_unregister(hdev);
2451
2452         return ret;
2453 }
2454 EXPORT_SYMBOL_GPL(hid_add_device);
2455
2456 /**
2457  * hid_allocate_device - allocate new hid device descriptor
2458  *
2459  * Allocate and initialize hid device, so that hid_destroy_device might be
2460  * used to free it.
2461  *
2462  * New hid_device pointer is returned on success, otherwise ERR_PTR encoded
2463  * error value.
2464  */
2465 struct hid_device *hid_allocate_device(void)
2466 {
2467         struct hid_device *hdev;
2468         int ret = -ENOMEM;
2469
2470         hdev = kzalloc(sizeof(*hdev), GFP_KERNEL);
2471         if (hdev == NULL)
2472                 return ERR_PTR(ret);
2473
2474         device_initialize(&hdev->dev);
2475         hdev->dev.release = hid_device_release;
2476         hdev->dev.bus = &hid_bus_type;
2477         device_enable_async_suspend(&hdev->dev);
2478
2479         hid_close_report(hdev);
2480
2481         init_waitqueue_head(&hdev->debug_wait);
2482         INIT_LIST_HEAD(&hdev->debug_list);
2483         spin_lock_init(&hdev->debug_list_lock);
2484         sema_init(&hdev->driver_input_lock, 1);
2485         mutex_init(&hdev->ll_open_lock);
2486
2487         return hdev;
2488 }
2489 EXPORT_SYMBOL_GPL(hid_allocate_device);
2490
2491 static void hid_remove_device(struct hid_device *hdev)
2492 {
2493         if (hdev->status & HID_STAT_ADDED) {
2494                 device_del(&hdev->dev);
2495                 hid_debug_unregister(hdev);
2496                 hdev->status &= ~HID_STAT_ADDED;
2497         }
2498         kfree(hdev->dev_rdesc);
2499         hdev->dev_rdesc = NULL;
2500         hdev->dev_rsize = 0;
2501 }
2502
2503 /**
2504  * hid_destroy_device - free previously allocated device
2505  *
2506  * @hdev: hid device
2507  *
2508  * If you allocate hid_device through hid_allocate_device, you should ever
2509  * free by this function.
2510  */
2511 void hid_destroy_device(struct hid_device *hdev)
2512 {
2513         hid_remove_device(hdev);
2514         put_device(&hdev->dev);
2515 }
2516 EXPORT_SYMBOL_GPL(hid_destroy_device);
2517
2518
2519 static int __hid_bus_reprobe_drivers(struct device *dev, void *data)
2520 {
2521         struct hid_driver *hdrv = data;
2522         struct hid_device *hdev = to_hid_device(dev);
2523
2524         if (hdev->driver == hdrv &&
2525             !hdrv->match(hdev, hid_ignore_special_drivers) &&
2526             !test_and_set_bit(ffs(HID_STAT_REPROBED), &hdev->status))
2527                 return device_reprobe(dev);
2528
2529         return 0;
2530 }
2531
2532 static int __hid_bus_driver_added(struct device_driver *drv, void *data)
2533 {
2534         struct hid_driver *hdrv = to_hid_driver(drv);
2535
2536         if (hdrv->match) {
2537                 bus_for_each_dev(&hid_bus_type, NULL, hdrv,
2538                                  __hid_bus_reprobe_drivers);
2539         }
2540
2541         return 0;
2542 }
2543
2544 static int __bus_removed_driver(struct device_driver *drv, void *data)
2545 {
2546         return bus_rescan_devices(&hid_bus_type);
2547 }
2548
2549 int __hid_register_driver(struct hid_driver *hdrv, struct module *owner,
2550                 const char *mod_name)
2551 {
2552         int ret;
2553
2554         hdrv->driver.name = hdrv->name;
2555         hdrv->driver.bus = &hid_bus_type;
2556         hdrv->driver.owner = owner;
2557         hdrv->driver.mod_name = mod_name;
2558
2559         INIT_LIST_HEAD(&hdrv->dyn_list);
2560         spin_lock_init(&hdrv->dyn_lock);
2561
2562         ret = driver_register(&hdrv->driver);
2563
2564         if (ret == 0)
2565                 bus_for_each_drv(&hid_bus_type, NULL, NULL,
2566                                  __hid_bus_driver_added);
2567
2568         return ret;
2569 }
2570 EXPORT_SYMBOL_GPL(__hid_register_driver);
2571
2572 void hid_unregister_driver(struct hid_driver *hdrv)
2573 {
2574         driver_unregister(&hdrv->driver);
2575         hid_free_dynids(hdrv);
2576
2577         bus_for_each_drv(&hid_bus_type, NULL, hdrv, __bus_removed_driver);
2578 }
2579 EXPORT_SYMBOL_GPL(hid_unregister_driver);
2580
2581 int hid_check_keys_pressed(struct hid_device *hid)
2582 {
2583         struct hid_input *hidinput;
2584         int i;
2585
2586         if (!(hid->claimed & HID_CLAIMED_INPUT))
2587                 return 0;
2588
2589         list_for_each_entry(hidinput, &hid->inputs, list) {
2590                 for (i = 0; i < BITS_TO_LONGS(KEY_MAX); i++)
2591                         if (hidinput->input->key[i])
2592                                 return 1;
2593         }
2594
2595         return 0;
2596 }
2597
2598 EXPORT_SYMBOL_GPL(hid_check_keys_pressed);
2599
2600 static int __init hid_init(void)
2601 {
2602         int ret;
2603
2604         if (hid_debug)
2605                 pr_warn("hid_debug is now used solely for parser and driver debugging.\n"
2606                         "debugfs is now used for inspecting the device (report descriptor, reports)\n");
2607
2608         ret = bus_register(&hid_bus_type);
2609         if (ret) {
2610                 pr_err("can't register hid bus\n");
2611                 goto err;
2612         }
2613
2614         ret = hidraw_init();
2615         if (ret)
2616                 goto err_bus;
2617
2618         hid_debug_init();
2619
2620         return 0;
2621 err_bus:
2622         bus_unregister(&hid_bus_type);
2623 err:
2624         return ret;
2625 }
2626
2627 static void __exit hid_exit(void)
2628 {
2629         hid_debug_exit();
2630         hidraw_exit();
2631         bus_unregister(&hid_bus_type);
2632         hid_quirks_exit(HID_BUS_ANY);
2633 }
2634
2635 module_init(hid_init);
2636 module_exit(hid_exit);
2637
2638 MODULE_AUTHOR("Andreas Gal");
2639 MODULE_AUTHOR("Vojtech Pavlik");
2640 MODULE_AUTHOR("Jiri Kosina");
2641 MODULE_LICENSE("GPL");