linux/drivers/hid/hid-core.c
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   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
  44int hid_debug = 0;
  45module_param_named(debug, hid_debug, int, 0600);
  46MODULE_PARM_DESC(debug, "toggle HID debugging messages");
  47EXPORT_SYMBOL_GPL(hid_debug);
  48
  49static int hid_ignore_special_drivers = 0;
  50module_param_named(ignore_special_drivers, hid_ignore_special_drivers, int, 0600);
  51MODULE_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
  57struct 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}
  87EXPORT_SYMBOL_GPL(hid_register_report);
  88
  89/*
  90 * Register a new field for this report.
  91 */
  92
  93static 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
 121static 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
 186static 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
 201static 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
 219static 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
 230static 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
 257static int hid_add_field(struct hid_parser *parser, unsigned report_type, unsigned flags)
 258{
 259        struct hid_report *report;
 260        struct hid_field *field;
 261        unsigned int usages;
 262        unsigned int offset;
 263        unsigned int i;
 264        unsigned int application;
 265
 266        application = hid_lookup_collection(parser, HID_COLLECTION_APPLICATION);
 267
 268        report = hid_register_report(parser->device, report_type,
 269                                     parser->global.report_id, application);
 270        if (!report) {
 271                hid_err(parser->device, "hid_register_report failed\n");
 272                return -1;
 273        }
 274
 275        /* Handle both signed and unsigned cases properly */
 276        if ((parser->global.logical_minimum < 0 &&
 277                parser->global.logical_maximum <
 278                parser->global.logical_minimum) ||
 279                (parser->global.logical_minimum >= 0 &&
 280                (__u32)parser->global.logical_maximum <
 281                (__u32)parser->global.logical_minimum)) {
 282                dbg_hid("logical range invalid 0x%x 0x%x\n",
 283                        parser->global.logical_minimum,
 284                        parser->global.logical_maximum);
 285                return -1;
 286        }
 287
 288        offset = report->size;
 289        report->size += parser->global.report_size * parser->global.report_count;
 290
 291        /* Total size check: Allow for possible report index byte */
 292        if (report->size > (HID_MAX_BUFFER_SIZE - 1) << 3) {
 293                hid_err(parser->device, "report is too long\n");
 294                return -1;
 295        }
 296
 297        if (!parser->local.usage_index) /* Ignore padding fields */
 298                return 0;
 299
 300        usages = max_t(unsigned, parser->local.usage_index,
 301                                 parser->global.report_count);
 302
 303        field = hid_register_field(report, usages);
 304        if (!field)
 305                return 0;
 306
 307        field->physical = hid_lookup_collection(parser, HID_COLLECTION_PHYSICAL);
 308        field->logical = hid_lookup_collection(parser, HID_COLLECTION_LOGICAL);
 309        field->application = application;
 310
 311        for (i = 0; i < usages; i++) {
 312                unsigned j = i;
 313                /* Duplicate the last usage we parsed if we have excess values */
 314                if (i >= parser->local.usage_index)
 315                        j = parser->local.usage_index - 1;
 316                field->usage[i].hid = parser->local.usage[j];
 317                field->usage[i].collection_index =
 318                        parser->local.collection_index[j];
 319                field->usage[i].usage_index = i;
 320                field->usage[i].resolution_multiplier = 1;
 321        }
 322
 323        field->maxusage = usages;
 324        field->flags = flags;
 325        field->report_offset = offset;
 326        field->report_type = report_type;
 327        field->report_size = parser->global.report_size;
 328        field->report_count = parser->global.report_count;
 329        field->logical_minimum = parser->global.logical_minimum;
 330        field->logical_maximum = parser->global.logical_maximum;
 331        field->physical_minimum = parser->global.physical_minimum;
 332        field->physical_maximum = parser->global.physical_maximum;
 333        field->unit_exponent = parser->global.unit_exponent;
 334        field->unit = parser->global.unit;
 335
 336        return 0;
 337}
 338
 339/*
 340 * Read data value from item.
 341 */
 342
 343static u32 item_udata(struct hid_item *item)
 344{
 345        switch (item->size) {
 346        case 1: return item->data.u8;
 347        case 2: return item->data.u16;
 348        case 4: return item->data.u32;
 349        }
 350        return 0;
 351}
 352
 353static s32 item_sdata(struct hid_item *item)
 354{
 355        switch (item->size) {
 356        case 1: return item->data.s8;
 357        case 2: return item->data.s16;
 358        case 4: return item->data.s32;
 359        }
 360        return 0;
 361}
 362
 363/*
 364 * Process a global item.
 365 */
 366
 367static int hid_parser_global(struct hid_parser *parser, struct hid_item *item)
 368{
 369        __s32 raw_value;
 370        switch (item->tag) {
 371        case HID_GLOBAL_ITEM_TAG_PUSH:
 372
 373                if (parser->global_stack_ptr == HID_GLOBAL_STACK_SIZE) {
 374                        hid_err(parser->device, "global environment stack overflow\n");
 375                        return -1;
 376                }
 377
 378                memcpy(parser->global_stack + parser->global_stack_ptr++,
 379                        &parser->global, sizeof(struct hid_global));
 380                return 0;
 381
 382        case HID_GLOBAL_ITEM_TAG_POP:
 383
 384                if (!parser->global_stack_ptr) {
 385                        hid_err(parser->device, "global environment stack underflow\n");
 386                        return -1;
 387                }
 388
 389                memcpy(&parser->global, parser->global_stack +
 390                        --parser->global_stack_ptr, sizeof(struct hid_global));
 391                return 0;
 392
 393        case HID_GLOBAL_ITEM_TAG_USAGE_PAGE:
 394                parser->global.usage_page = item_udata(item);
 395                return 0;
 396
 397        case HID_GLOBAL_ITEM_TAG_LOGICAL_MINIMUM:
 398                parser->global.logical_minimum = item_sdata(item);
 399                return 0;
 400
 401        case HID_GLOBAL_ITEM_TAG_LOGICAL_MAXIMUM:
 402                if (parser->global.logical_minimum < 0)
 403                        parser->global.logical_maximum = item_sdata(item);
 404                else
 405                        parser->global.logical_maximum = item_udata(item);
 406                return 0;
 407
 408        case HID_GLOBAL_ITEM_TAG_PHYSICAL_MINIMUM:
 409                parser->global.physical_minimum = item_sdata(item);
 410                return 0;
 411
 412        case HID_GLOBAL_ITEM_TAG_PHYSICAL_MAXIMUM:
 413                if (parser->global.physical_minimum < 0)
 414                        parser->global.physical_maximum = item_sdata(item);
 415                else
 416                        parser->global.physical_maximum = item_udata(item);
 417                return 0;
 418
 419        case HID_GLOBAL_ITEM_TAG_UNIT_EXPONENT:
 420                /* Many devices provide unit exponent as a two's complement
 421                 * nibble due to the common misunderstanding of HID
 422                 * specification 1.11, 6.2.2.7 Global Items. Attempt to handle
 423                 * both this and the standard encoding. */
 424                raw_value = item_sdata(item);
 425                if (!(raw_value & 0xfffffff0))
 426                        parser->global.unit_exponent = hid_snto32(raw_value, 4);
 427                else
 428                        parser->global.unit_exponent = raw_value;
 429                return 0;
 430
 431        case HID_GLOBAL_ITEM_TAG_UNIT:
 432                parser->global.unit = item_udata(item);
 433                return 0;
 434
 435        case HID_GLOBAL_ITEM_TAG_REPORT_SIZE:
 436                parser->global.report_size = item_udata(item);
 437                if (parser->global.report_size > 256) {
 438                        hid_err(parser->device, "invalid report_size %d\n",
 439                                        parser->global.report_size);
 440                        return -1;
 441                }
 442                return 0;
 443
 444        case HID_GLOBAL_ITEM_TAG_REPORT_COUNT:
 445                parser->global.report_count = item_udata(item);
 446                if (parser->global.report_count > HID_MAX_USAGES) {
 447                        hid_err(parser->device, "invalid report_count %d\n",
 448                                        parser->global.report_count);
 449                        return -1;
 450                }
 451                return 0;
 452
 453        case HID_GLOBAL_ITEM_TAG_REPORT_ID:
 454                parser->global.report_id = item_udata(item);
 455                if (parser->global.report_id == 0 ||
 456                    parser->global.report_id >= HID_MAX_IDS) {
 457                        hid_err(parser->device, "report_id %u is invalid\n",
 458                                parser->global.report_id);
 459                        return -1;
 460                }
 461                return 0;
 462
 463        default:
 464                hid_err(parser->device, "unknown global tag 0x%x\n", item->tag);
 465                return -1;
 466        }
 467}
 468
 469/*
 470 * Process a local item.
 471 */
 472
 473static int hid_parser_local(struct hid_parser *parser, struct hid_item *item)
 474{
 475        __u32 data;
 476        unsigned n;
 477        __u32 count;
 478
 479        data = item_udata(item);
 480
 481        switch (item->tag) {
 482        case HID_LOCAL_ITEM_TAG_DELIMITER:
 483
 484                if (data) {
 485                        /*
 486                         * We treat items before the first delimiter
 487                         * as global to all usage sets (branch 0).
 488                         * In the moment we process only these global
 489                         * items and the first delimiter set.
 490                         */
 491                        if (parser->local.delimiter_depth != 0) {
 492                                hid_err(parser->device, "nested delimiters\n");
 493                                return -1;
 494                        }
 495                        parser->local.delimiter_depth++;
 496                        parser->local.delimiter_branch++;
 497                } else {
 498                        if (parser->local.delimiter_depth < 1) {
 499                                hid_err(parser->device, "bogus close delimiter\n");
 500                                return -1;
 501                        }
 502                        parser->local.delimiter_depth--;
 503                }
 504                return 0;
 505
 506        case HID_LOCAL_ITEM_TAG_USAGE:
 507
 508                if (parser->local.delimiter_branch > 1) {
 509                        dbg_hid("alternative usage ignored\n");
 510                        return 0;
 511                }
 512
 513                return hid_add_usage(parser, data, item->size);
 514
 515        case HID_LOCAL_ITEM_TAG_USAGE_MINIMUM:
 516
 517                if (parser->local.delimiter_branch > 1) {
 518                        dbg_hid("alternative usage ignored\n");
 519                        return 0;
 520                }
 521
 522                parser->local.usage_minimum = data;
 523                return 0;
 524
 525        case HID_LOCAL_ITEM_TAG_USAGE_MAXIMUM:
 526
 527                if (parser->local.delimiter_branch > 1) {
 528                        dbg_hid("alternative usage ignored\n");
 529                        return 0;
 530                }
 531
 532                count = data - parser->local.usage_minimum;
 533                if (count + parser->local.usage_index >= HID_MAX_USAGES) {
 534                        /*
 535                         * We do not warn if the name is not set, we are
 536                         * actually pre-scanning the device.
 537                         */
 538                        if (dev_name(&parser->device->dev))
 539                                hid_warn(parser->device,
 540                                         "ignoring exceeding usage max\n");
 541                        data = HID_MAX_USAGES - parser->local.usage_index +
 542                                parser->local.usage_minimum - 1;
 543                        if (data <= 0) {
 544                                hid_err(parser->device,
 545                                        "no more usage index available\n");
 546                                return -1;
 547                        }
 548                }
 549
 550                for (n = parser->local.usage_minimum; n <= data; n++)
 551                        if (hid_add_usage(parser, n, item->size)) {
 552                                dbg_hid("hid_add_usage failed\n");
 553                                return -1;
 554                        }
 555                return 0;
 556
 557        default:
 558
 559                dbg_hid("unknown local item tag 0x%x\n", item->tag);
 560                return 0;
 561        }
 562        return 0;
 563}
 564
 565/*
 566 * Concatenate Usage Pages into Usages where relevant:
 567 * As per specification, 6.2.2.8: "When the parser encounters a main item it
 568 * concatenates the last declared Usage Page with a Usage to form a complete
 569 * usage value."
 570 */
 571
 572static void hid_concatenate_last_usage_page(struct hid_parser *parser)
 573{
 574        int i;
 575        unsigned int usage_page;
 576        unsigned int current_page;
 577
 578        if (!parser->local.usage_index)
 579                return;
 580
 581        usage_page = parser->global.usage_page;
 582
 583        /*
 584         * Concatenate usage page again only if last declared Usage Page
 585         * has not been already used in previous usages concatenation
 586         */
 587        for (i = parser->local.usage_index - 1; i >= 0; i--) {
 588                if (parser->local.usage_size[i] > 2)
 589                        /* Ignore extended usages */
 590                        continue;
 591
 592                current_page = parser->local.usage[i] >> 16;
 593                if (current_page == usage_page)
 594                        break;
 595
 596                complete_usage(parser, i);
 597        }
 598}
 599
 600/*
 601 * Process a main item.
 602 */
 603
 604static int hid_parser_main(struct hid_parser *parser, struct hid_item *item)
 605{
 606        __u32 data;
 607        int ret;
 608
 609        hid_concatenate_last_usage_page(parser);
 610
 611        data = item_udata(item);
 612
 613        switch (item->tag) {
 614        case HID_MAIN_ITEM_TAG_BEGIN_COLLECTION:
 615                ret = open_collection(parser, data & 0xff);
 616                break;
 617        case HID_MAIN_ITEM_TAG_END_COLLECTION:
 618                ret = close_collection(parser);
 619                break;
 620        case HID_MAIN_ITEM_TAG_INPUT:
 621                ret = hid_add_field(parser, HID_INPUT_REPORT, data);
 622                break;
 623        case HID_MAIN_ITEM_TAG_OUTPUT:
 624                ret = hid_add_field(parser, HID_OUTPUT_REPORT, data);
 625                break;
 626        case HID_MAIN_ITEM_TAG_FEATURE:
 627                ret = hid_add_field(parser, HID_FEATURE_REPORT, data);
 628                break;
 629        default:
 630                hid_warn(parser->device, "unknown main item tag 0x%x\n", item->tag);
 631                ret = 0;
 632        }
 633
 634        memset(&parser->local, 0, sizeof(parser->local));       /* Reset the local parser environment */
 635
 636        return ret;
 637}
 638
 639/*
 640 * Process a reserved item.
 641 */
 642
 643static int hid_parser_reserved(struct hid_parser *parser, struct hid_item *item)
 644{
 645        dbg_hid("reserved item type, tag 0x%x\n", item->tag);
 646        return 0;
 647}
 648
 649/*
 650 * Free a report and all registered fields. The field->usage and
 651 * field->value table's are allocated behind the field, so we need
 652 * only to free(field) itself.
 653 */
 654
 655static void hid_free_report(struct hid_report *report)
 656{
 657        unsigned n;
 658
 659        for (n = 0; n < report->maxfield; n++)
 660                kfree(report->field[n]);
 661        kfree(report);
 662}
 663
 664/*
 665 * Close report. This function returns the device
 666 * state to the point prior to hid_open_report().
 667 */
 668static void hid_close_report(struct hid_device *device)
 669{
 670        unsigned i, j;
 671
 672        for (i = 0; i < HID_REPORT_TYPES; i++) {
 673                struct hid_report_enum *report_enum = device->report_enum + i;
 674
 675                for (j = 0; j < HID_MAX_IDS; j++) {
 676                        struct hid_report *report = report_enum->report_id_hash[j];
 677                        if (report)
 678                                hid_free_report(report);
 679                }
 680                memset(report_enum, 0, sizeof(*report_enum));
 681                INIT_LIST_HEAD(&report_enum->report_list);
 682        }
 683
 684        kfree(device->rdesc);
 685        device->rdesc = NULL;
 686        device->rsize = 0;
 687
 688        kfree(device->collection);
 689        device->collection = NULL;
 690        device->collection_size = 0;
 691        device->maxcollection = 0;
 692        device->maxapplication = 0;
 693
 694        device->status &= ~HID_STAT_PARSED;
 695}
 696
 697/*
 698 * Free a device structure, all reports, and all fields.
 699 */
 700
 701static void hid_device_release(struct device *dev)
 702{
 703        struct hid_device *hid = to_hid_device(dev);
 704
 705        hid_close_report(hid);
 706        kfree(hid->dev_rdesc);
 707        kfree(hid);
 708}
 709
 710/*
 711 * Fetch a report description item from the data stream. We support long
 712 * items, though they are not used yet.
 713 */
 714
 715static u8 *fetch_item(__u8 *start, __u8 *end, struct hid_item *item)
 716{
 717        u8 b;
 718
 719        if ((end - start) <= 0)
 720                return NULL;
 721
 722        b = *start++;
 723
 724        item->type = (b >> 2) & 3;
 725        item->tag  = (b >> 4) & 15;
 726
 727        if (item->tag == HID_ITEM_TAG_LONG) {
 728
 729                item->format = HID_ITEM_FORMAT_LONG;
 730
 731                if ((end - start) < 2)
 732                        return NULL;
 733
 734                item->size = *start++;
 735                item->tag  = *start++;
 736
 737                if ((end - start) < item->size)
 738                        return NULL;
 739
 740                item->data.longdata = start;
 741                start += item->size;
 742                return start;
 743        }
 744
 745        item->format = HID_ITEM_FORMAT_SHORT;
 746        item->size = b & 3;
 747
 748        switch (item->size) {
 749        case 0:
 750                return start;
 751
 752        case 1:
 753                if ((end - start) < 1)
 754                        return NULL;
 755                item->data.u8 = *start++;
 756                return start;
 757
 758        case 2:
 759                if ((end - start) < 2)
 760                        return NULL;
 761                item->data.u16 = get_unaligned_le16(start);
 762                start = (__u8 *)((__le16 *)start + 1);
 763                return start;
 764
 765        case 3:
 766                item->size++;
 767                if ((end - start) < 4)
 768                        return NULL;
 769                item->data.u32 = get_unaligned_le32(start);
 770                start = (__u8 *)((__le32 *)start + 1);
 771                return start;
 772        }
 773
 774        return NULL;
 775}
 776
 777static void hid_scan_input_usage(struct hid_parser *parser, u32 usage)
 778{
 779        struct hid_device *hid = parser->device;
 780
 781        if (usage == HID_DG_CONTACTID)
 782                hid->group = HID_GROUP_MULTITOUCH;
 783}
 784
 785static void hid_scan_feature_usage(struct hid_parser *parser, u32 usage)
 786{
 787        if (usage == 0xff0000c5 && parser->global.report_count == 256 &&
 788            parser->global.report_size == 8)
 789                parser->scan_flags |= HID_SCAN_FLAG_MT_WIN_8;
 790
 791        if (usage == 0xff0000c6 && parser->global.report_count == 1 &&
 792            parser->global.report_size == 8)
 793                parser->scan_flags |= HID_SCAN_FLAG_MT_WIN_8;
 794}
 795
 796static void hid_scan_collection(struct hid_parser *parser, unsigned type)
 797{
 798        struct hid_device *hid = parser->device;
 799        int i;
 800
 801        if (((parser->global.usage_page << 16) == HID_UP_SENSOR) &&
 802            type == HID_COLLECTION_PHYSICAL)
 803                hid->group = HID_GROUP_SENSOR_HUB;
 804
 805        if (hid->vendor == USB_VENDOR_ID_MICROSOFT &&
 806            hid->product == USB_DEVICE_ID_MS_POWER_COVER &&
 807            hid->group == HID_GROUP_MULTITOUCH)
 808                hid->group = HID_GROUP_GENERIC;
 809
 810        if ((parser->global.usage_page << 16) == HID_UP_GENDESK)
 811                for (i = 0; i < parser->local.usage_index; i++)
 812                        if (parser->local.usage[i] == HID_GD_POINTER)
 813                                parser->scan_flags |= HID_SCAN_FLAG_GD_POINTER;
 814
 815        if ((parser->global.usage_page << 16) >= HID_UP_MSVENDOR)
 816                parser->scan_flags |= HID_SCAN_FLAG_VENDOR_SPECIFIC;
 817
 818        if ((parser->global.usage_page << 16) == HID_UP_GOOGLEVENDOR)
 819                for (i = 0; i < parser->local.usage_index; i++)
 820                        if (parser->local.usage[i] ==
 821                                        (HID_UP_GOOGLEVENDOR | 0x0001))
 822                                parser->device->group =
 823                                        HID_GROUP_VIVALDI;
 824}
 825
 826static int hid_scan_main(struct hid_parser *parser, struct hid_item *item)
 827{
 828        __u32 data;
 829        int i;
 830
 831        hid_concatenate_last_usage_page(parser);
 832
 833        data = item_udata(item);
 834
 835        switch (item->tag) {
 836        case HID_MAIN_ITEM_TAG_BEGIN_COLLECTION:
 837                hid_scan_collection(parser, data & 0xff);
 838                break;
 839        case HID_MAIN_ITEM_TAG_END_COLLECTION:
 840                break;
 841        case HID_MAIN_ITEM_TAG_INPUT:
 842                /* ignore constant inputs, they will be ignored by hid-input */
 843                if (data & HID_MAIN_ITEM_CONSTANT)
 844                        break;
 845                for (i = 0; i < parser->local.usage_index; i++)
 846                        hid_scan_input_usage(parser, parser->local.usage[i]);
 847                break;
 848        case HID_MAIN_ITEM_TAG_OUTPUT:
 849                break;
 850        case HID_MAIN_ITEM_TAG_FEATURE:
 851                for (i = 0; i < parser->local.usage_index; i++)
 852                        hid_scan_feature_usage(parser, parser->local.usage[i]);
 853                break;
 854        }
 855
 856        /* Reset the local parser environment */
 857        memset(&parser->local, 0, sizeof(parser->local));
 858
 859        return 0;
 860}
 861
 862/*
 863 * Scan a report descriptor before the device is added to the bus.
 864 * Sets device groups and other properties that determine what driver
 865 * to load.
 866 */
 867static int hid_scan_report(struct hid_device *hid)
 868{
 869        struct hid_parser *parser;
 870        struct hid_item item;
 871        __u8 *start = hid->dev_rdesc;
 872        __u8 *end = start + hid->dev_rsize;
 873        static int (*dispatch_type[])(struct hid_parser *parser,
 874                                      struct hid_item *item) = {
 875                hid_scan_main,
 876                hid_parser_global,
 877                hid_parser_local,
 878                hid_parser_reserved
 879        };
 880
 881        parser = vzalloc(sizeof(struct hid_parser));
 882        if (!parser)
 883                return -ENOMEM;
 884
 885        parser->device = hid;
 886        hid->group = HID_GROUP_GENERIC;
 887
 888        /*
 889         * The parsing is simpler than the one in hid_open_report() as we should
 890         * be robust against hid errors. Those errors will be raised by
 891         * hid_open_report() anyway.
 892         */
 893        while ((start = fetch_item(start, end, &item)) != NULL)
 894                dispatch_type[item.type](parser, &item);
 895
 896        /*
 897         * Handle special flags set during scanning.
 898         */
 899        if ((parser->scan_flags & HID_SCAN_FLAG_MT_WIN_8) &&
 900            (hid->group == HID_GROUP_MULTITOUCH))
 901                hid->group = HID_GROUP_MULTITOUCH_WIN_8;
 902
 903        /*
 904         * Vendor specific handlings
 905         */
 906        switch (hid->vendor) {
 907        case USB_VENDOR_ID_WACOM:
 908                hid->group = HID_GROUP_WACOM;
 909                break;
 910        case USB_VENDOR_ID_SYNAPTICS:
 911                if (hid->group == HID_GROUP_GENERIC)
 912                        if ((parser->scan_flags & HID_SCAN_FLAG_VENDOR_SPECIFIC)
 913                            && (parser->scan_flags & HID_SCAN_FLAG_GD_POINTER))
 914                                /*
 915                                 * hid-rmi should take care of them,
 916                                 * not hid-generic
 917                                 */
 918                                hid->group = HID_GROUP_RMI;
 919                break;
 920        }
 921
 922        kfree(parser->collection_stack);
 923        vfree(parser);
 924        return 0;
 925}
 926
 927/**
 928 * hid_parse_report - parse device report
 929 *
 930 * @hid: hid device
 931 * @start: report start
 932 * @size: report size
 933 *
 934 * Allocate the device report as read by the bus driver. This function should
 935 * only be called from parse() in ll drivers.
 936 */
 937int hid_parse_report(struct hid_device *hid, __u8 *start, unsigned size)
 938{
 939        hid->dev_rdesc = kmemdup(start, size, GFP_KERNEL);
 940        if (!hid->dev_rdesc)
 941                return -ENOMEM;
 942        hid->dev_rsize = size;
 943        return 0;
 944}
 945EXPORT_SYMBOL_GPL(hid_parse_report);
 946
 947static const char * const hid_report_names[] = {
 948        "HID_INPUT_REPORT",
 949        "HID_OUTPUT_REPORT",
 950        "HID_FEATURE_REPORT",
 951};
 952/**
 953 * hid_validate_values - validate existing device report's value indexes
 954 *
 955 * @hid: hid device
 956 * @type: which report type to examine
 957 * @id: which report ID to examine (0 for first)
 958 * @field_index: which report field to examine
 959 * @report_counts: expected number of values
 960 *
 961 * Validate the number of values in a given field of a given report, after
 962 * parsing.
 963 */
 964struct hid_report *hid_validate_values(struct hid_device *hid,
 965                                       unsigned int type, unsigned int id,
 966                                       unsigned int field_index,
 967                                       unsigned int report_counts)
 968{
 969        struct hid_report *report;
 970
 971        if (type > HID_FEATURE_REPORT) {
 972                hid_err(hid, "invalid HID report type %u\n", type);
 973                return NULL;
 974        }
 975
 976        if (id >= HID_MAX_IDS) {
 977                hid_err(hid, "invalid HID report id %u\n", id);
 978                return NULL;
 979        }
 980
 981        /*
 982         * Explicitly not using hid_get_report() here since it depends on
 983         * ->numbered being checked, which may not always be the case when
 984         * drivers go to access report values.
 985         */
 986        if (id == 0) {
 987                /*
 988                 * Validating on id 0 means we should examine the first
 989                 * report in the list.
 990                 */
 991                report = list_entry(
 992                                hid->report_enum[type].report_list.next,
 993                                struct hid_report, list);
 994        } else {
 995                report = hid->report_enum[type].report_id_hash[id];
 996        }
 997        if (!report) {
 998                hid_err(hid, "missing %s %u\n", hid_report_names[type], id);
 999                return NULL;
1000        }
1001        if (report->maxfield <= field_index) {
1002                hid_err(hid, "not enough fields in %s %u\n",
1003                        hid_report_names[type], id);
1004                return NULL;
1005        }
1006        if (report->field[field_index]->report_count < report_counts) {
1007                hid_err(hid, "not enough values in %s %u field %u\n",
1008                        hid_report_names[type], id, field_index);
1009                return NULL;
1010        }
1011        return report;
1012}
1013EXPORT_SYMBOL_GPL(hid_validate_values);
1014
1015static int hid_calculate_multiplier(struct hid_device *hid,
1016                                     struct hid_field *multiplier)
1017{
1018        int m;
1019        __s32 v = *multiplier->value;
1020        __s32 lmin = multiplier->logical_minimum;
1021        __s32 lmax = multiplier->logical_maximum;
1022        __s32 pmin = multiplier->physical_minimum;
1023        __s32 pmax = multiplier->physical_maximum;
1024
1025        /*
1026         * "Because OS implementations will generally divide the control's
1027         * reported count by the Effective Resolution Multiplier, designers
1028         * should take care not to establish a potential Effective
1029         * Resolution Multiplier of zero."
1030         * HID Usage Table, v1.12, Section 4.3.1, p31
1031         */
1032        if (lmax - lmin == 0)
1033                return 1;
1034        /*
1035         * Handling the unit exponent is left as an exercise to whoever
1036         * finds a device where that exponent is not 0.
1037         */
1038        m = ((v - lmin)/(lmax - lmin) * (pmax - pmin) + pmin);
1039        if (unlikely(multiplier->unit_exponent != 0)) {
1040                hid_warn(hid,
1041                         "unsupported Resolution Multiplier unit exponent %d\n",
1042                         multiplier->unit_exponent);
1043        }
1044
1045        /* There are no devices with an effective multiplier > 255 */
1046        if (unlikely(m == 0 || m > 255 || m < -255)) {
1047                hid_warn(hid, "unsupported Resolution Multiplier %d\n", m);
1048                m = 1;
1049        }
1050
1051        return m;
1052}
1053
1054static void hid_apply_multiplier_to_field(struct hid_device *hid,
1055                                          struct hid_field *field,
1056                                          struct hid_collection *multiplier_collection,
1057                                          int effective_multiplier)
1058{
1059        struct hid_collection *collection;
1060        struct hid_usage *usage;
1061        int i;
1062
1063        /*
1064         * If multiplier_collection is NULL, the multiplier applies
1065         * to all fields in the report.
1066         * Otherwise, it is the Logical Collection the multiplier applies to
1067         * but our field may be in a subcollection of that collection.
1068         */
1069        for (i = 0; i < field->maxusage; i++) {
1070                usage = &field->usage[i];
1071
1072                collection = &hid->collection[usage->collection_index];
1073                while (collection->parent_idx != -1 &&
1074                       collection != multiplier_collection)
1075                        collection = &hid->collection[collection->parent_idx];
1076
1077                if (collection->parent_idx != -1 ||
1078                    multiplier_collection == NULL)
1079                        usage->resolution_multiplier = effective_multiplier;
1080
1081        }
1082}
1083
1084static void hid_apply_multiplier(struct hid_device *hid,
1085                                 struct hid_field *multiplier)
1086{
1087        struct hid_report_enum *rep_enum;
1088        struct hid_report *rep;
1089        struct hid_field *field;
1090        struct hid_collection *multiplier_collection;
1091        int effective_multiplier;
1092        int i;
1093
1094        /*
1095         * "The Resolution Multiplier control must be contained in the same
1096         * Logical Collection as the control(s) to which it is to be applied.
1097         * If no Resolution Multiplier is defined, then the Resolution
1098         * Multiplier defaults to 1.  If more than one control exists in a
1099         * Logical Collection, the Resolution Multiplier is associated with
1100         * all controls in the collection. If no Logical Collection is
1101         * defined, the Resolution Multiplier is associated with all
1102         * controls in the report."
1103         * HID Usage Table, v1.12, Section 4.3.1, p30
1104         *
1105         * Thus, search from the current collection upwards until we find a
1106         * logical collection. Then search all fields for that same parent
1107         * collection. Those are the fields the multiplier applies to.
1108         *
1109         * If we have more than one multiplier, it will overwrite the
1110         * applicable fields later.
1111         */
1112        multiplier_collection = &hid->collection[multiplier->usage->collection_index];
1113        while (multiplier_collection->parent_idx != -1 &&
1114               multiplier_collection->type != HID_COLLECTION_LOGICAL)
1115                multiplier_collection = &hid->collection[multiplier_collection->parent_idx];
1116
1117        effective_multiplier = hid_calculate_multiplier(hid, multiplier);
1118
1119        rep_enum = &hid->report_enum[HID_INPUT_REPORT];
1120        list_for_each_entry(rep, &rep_enum->report_list, list) {
1121                for (i = 0; i < rep->maxfield; i++) {
1122                        field = rep->field[i];
1123                        hid_apply_multiplier_to_field(hid, field,
1124                                                      multiplier_collection,
1125                                                      effective_multiplier);
1126                }
1127        }
1128}
1129
1130/*
1131 * hid_setup_resolution_multiplier - set up all resolution multipliers
1132 *
1133 * @device: hid device
1134 *
1135 * Search for all Resolution Multiplier Feature Reports and apply their
1136 * value to all matching Input items. This only updates the internal struct
1137 * fields.
1138 *
1139 * The Resolution Multiplier is applied by the hardware. If the multiplier
1140 * is anything other than 1, the hardware will send pre-multiplied events
1141 * so that the same physical interaction generates an accumulated
1142 *      accumulated_value = value * * multiplier
1143 * This may be achieved by sending
1144 * - "value * multiplier" for each event, or
1145 * - "value" but "multiplier" times as frequently, or
1146 * - a combination of the above
1147 * The only guarantee is that the same physical interaction always generates
1148 * an accumulated 'value * multiplier'.
1149 *
1150 * This function must be called before any event processing and after
1151 * any SetRequest to the Resolution Multiplier.
1152 */
1153void hid_setup_resolution_multiplier(struct hid_device *hid)
1154{
1155        struct hid_report_enum *rep_enum;
1156        struct hid_report *rep;
1157        struct hid_usage *usage;
1158        int i, j;
1159
1160        rep_enum = &hid->report_enum[HID_FEATURE_REPORT];
1161        list_for_each_entry(rep, &rep_enum->report_list, list) {
1162                for (i = 0; i < rep->maxfield; i++) {
1163                        /* Ignore if report count is out of bounds. */
1164                        if (rep->field[i]->report_count < 1)
1165                                continue;
1166
1167                        for (j = 0; j < rep->field[i]->maxusage; j++) {
1168                                usage = &rep->field[i]->usage[j];
1169                                if (usage->hid == HID_GD_RESOLUTION_MULTIPLIER)
1170                                        hid_apply_multiplier(hid,
1171                                                             rep->field[i]);
1172                        }
1173                }
1174        }
1175}
1176EXPORT_SYMBOL_GPL(hid_setup_resolution_multiplier);
1177
1178/**
1179 * hid_open_report - open a driver-specific device report
1180 *
1181 * @device: hid device
1182 *
1183 * Parse a report description into a hid_device structure. Reports are
1184 * enumerated, fields are attached to these reports.
1185 * 0 returned on success, otherwise nonzero error value.
1186 *
1187 * This function (or the equivalent hid_parse() macro) should only be
1188 * called from probe() in drivers, before starting the device.
1189 */
1190int hid_open_report(struct hid_device *device)
1191{
1192        struct hid_parser *parser;
1193        struct hid_item item;
1194        unsigned int size;
1195        __u8 *start;
1196        __u8 *buf;
1197        __u8 *end;
1198        __u8 *next;
1199        int ret;
1200        static int (*dispatch_type[])(struct hid_parser *parser,
1201                                      struct hid_item *item) = {
1202                hid_parser_main,
1203                hid_parser_global,
1204                hid_parser_local,
1205                hid_parser_reserved
1206        };
1207
1208        if (WARN_ON(device->status & HID_STAT_PARSED))
1209                return -EBUSY;
1210
1211        start = device->dev_rdesc;
1212        if (WARN_ON(!start))
1213                return -ENODEV;
1214        size = device->dev_rsize;
1215
1216        buf = kmemdup(start, size, GFP_KERNEL);
1217        if (buf == NULL)
1218                return -ENOMEM;
1219
1220        if (device->driver->report_fixup)
1221                start = device->driver->report_fixup(device, buf, &size);
1222        else
1223                start = buf;
1224
1225        start = kmemdup(start, size, GFP_KERNEL);
1226        kfree(buf);
1227        if (start == NULL)
1228                return -ENOMEM;
1229
1230        device->rdesc = start;
1231        device->rsize = size;
1232
1233        parser = vzalloc(sizeof(struct hid_parser));
1234        if (!parser) {
1235                ret = -ENOMEM;
1236                goto alloc_err;
1237        }
1238
1239        parser->device = device;
1240
1241        end = start + size;
1242
1243        device->collection = kcalloc(HID_DEFAULT_NUM_COLLECTIONS,
1244                                     sizeof(struct hid_collection), GFP_KERNEL);
1245        if (!device->collection) {
1246                ret = -ENOMEM;
1247                goto err;
1248        }
1249        device->collection_size = HID_DEFAULT_NUM_COLLECTIONS;
1250
1251        ret = -EINVAL;
1252        while ((next = fetch_item(start, end, &item)) != NULL) {
1253                start = next;
1254
1255                if (item.format != HID_ITEM_FORMAT_SHORT) {
1256                        hid_err(device, "unexpected long global item\n");
1257                        goto err;
1258                }
1259
1260                if (dispatch_type[item.type](parser, &item)) {
1261                        hid_err(device, "item %u %u %u %u parsing failed\n",
1262                                item.format, (unsigned)item.size,
1263                                (unsigned)item.type, (unsigned)item.tag);
1264                        goto err;
1265                }
1266
1267                if (start == end) {
1268                        if (parser->collection_stack_ptr) {
1269                                hid_err(device, "unbalanced collection at end of report description\n");
1270                                goto err;
1271                        }
1272                        if (parser->local.delimiter_depth) {
1273                                hid_err(device, "unbalanced delimiter at end of report description\n");
1274                                goto err;
1275                        }
1276
1277                        /*
1278                         * fetch initial values in case the device's
1279                         * default multiplier isn't the recommended 1
1280                         */
1281                        hid_setup_resolution_multiplier(device);
1282
1283                        kfree(parser->collection_stack);
1284                        vfree(parser);
1285                        device->status |= HID_STAT_PARSED;
1286
1287                        return 0;
1288                }
1289        }
1290
1291        hid_err(device, "item fetching failed at offset %u/%u\n",
1292                size - (unsigned int)(end - start), size);
1293err:
1294        kfree(parser->collection_stack);
1295alloc_err:
1296        vfree(parser);
1297        hid_close_report(device);
1298        return ret;
1299}
1300EXPORT_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
1308static s32 snto32(__u32 value, unsigned n)
1309{
1310        if (!value || !n)
1311                return 0;
1312
1313        switch (n) {
1314        case 8:  return ((__s8)value);
1315        case 16: return ((__s16)value);
1316        case 32: return ((__s32)value);
1317        }
1318        return value & (1 << (n - 1)) ? value | (~0U << n) : value;
1319}
1320
1321s32 hid_snto32(__u32 value, unsigned n)
1322{
1323        return snto32(value, n);
1324}
1325EXPORT_SYMBOL_GPL(hid_snto32);
1326
1327/*
1328 * Convert a signed 32-bit integer to a signed n-bit integer.
1329 */
1330
1331static u32 s32ton(__s32 value, unsigned n)
1332{
1333        s32 a = value >> (n - 1);
1334        if (a && a != -1)
1335                return value < 0 ? 1 << (n - 1) : (1 << (n - 1)) - 1;
1336        return value & ((1 << n) - 1);
1337}
1338
1339/*
1340 * Extract/implement a data field from/to a little endian report (bit array).
1341 *
1342 * Code sort-of follows HID spec:
1343 *     http://www.usb.org/developers/hidpage/HID1_11.pdf
1344 *
1345 * While the USB HID spec allows unlimited length bit fields in "report
1346 * descriptors", most devices never use more than 16 bits.
1347 * One model of UPS is claimed to report "LINEV" as a 32-bit field.
1348 * Search linux-kernel and linux-usb-devel archives for "hid-core extract".
1349 */
1350
1351static u32 __extract(u8 *report, unsigned offset, int n)
1352{
1353        unsigned int idx = offset / 8;
1354        unsigned int bit_nr = 0;
1355        unsigned int bit_shift = offset % 8;
1356        int bits_to_copy = 8 - bit_shift;
1357        u32 value = 0;
1358        u32 mask = n < 32 ? (1U << n) - 1 : ~0U;
1359
1360        while (n > 0) {
1361                value |= ((u32)report[idx] >> bit_shift) << bit_nr;
1362                n -= bits_to_copy;
1363                bit_nr += bits_to_copy;
1364                bits_to_copy = 8;
1365                bit_shift = 0;
1366                idx++;
1367        }
1368
1369        return value & mask;
1370}
1371
1372u32 hid_field_extract(const struct hid_device *hid, u8 *report,
1373                        unsigned offset, unsigned n)
1374{
1375        if (n > 32) {
1376                hid_warn_once(hid, "%s() called with n (%d) > 32! (%s)\n",
1377                              __func__, n, current->comm);
1378                n = 32;
1379        }
1380
1381        return __extract(report, offset, n);
1382}
1383EXPORT_SYMBOL_GPL(hid_field_extract);
1384
1385/*
1386 * "implement" : set bits in a little endian bit stream.
1387 * Same concepts as "extract" (see comments above).
1388 * The data mangled in the bit stream remains in little endian
1389 * order the whole time. It make more sense to talk about
1390 * endianness of register values by considering a register
1391 * a "cached" copy of the little endian bit stream.
1392 */
1393
1394static void __implement(u8 *report, unsigned offset, int n, u32 value)
1395{
1396        unsigned int idx = offset / 8;
1397        unsigned int bit_shift = offset % 8;
1398        int bits_to_set = 8 - bit_shift;
1399
1400        while (n - bits_to_set >= 0) {
1401                report[idx] &= ~(0xff << bit_shift);
1402                report[idx] |= value << bit_shift;
1403                value >>= bits_to_set;
1404                n -= bits_to_set;
1405                bits_to_set = 8;
1406                bit_shift = 0;
1407                idx++;
1408        }
1409
1410        /* last nibble */
1411        if (n) {
1412                u8 bit_mask = ((1U << n) - 1);
1413                report[idx] &= ~(bit_mask << bit_shift);
1414                report[idx] |= value << bit_shift;
1415        }
1416}
1417
1418static void implement(const struct hid_device *hid, u8 *report,
1419                      unsigned offset, unsigned n, u32 value)
1420{
1421        if (unlikely(n > 32)) {
1422                hid_warn(hid, "%s() called with n (%d) > 32! (%s)\n",
1423                         __func__, n, current->comm);
1424                n = 32;
1425        } else if (n < 32) {
1426                u32 m = (1U << n) - 1;
1427
1428                if (unlikely(value > m)) {
1429                        hid_warn(hid,
1430                                 "%s() called with too large value %d (n: %d)! (%s)\n",
1431                                 __func__, value, n, current->comm);
1432                        WARN_ON(1);
1433                        value &= m;
1434                }
1435        }
1436
1437        __implement(report, offset, n, value);
1438}
1439
1440/*
1441 * Search an array for a value.
1442 */
1443
1444static int search(__s32 *array, __s32 value, unsigned n)
1445{
1446        while (n--) {
1447                if (*array++ == value)
1448                        return 0;
1449        }
1450        return -1;
1451}
1452
1453/**
1454 * hid_match_report - check if driver's raw_event should be called
1455 *
1456 * @hid: hid device
1457 * @report: hid report to match against
1458 *
1459 * compare hid->driver->report_table->report_type to report->type
1460 */
1461static int hid_match_report(struct hid_device *hid, struct hid_report *report)
1462{
1463        const struct hid_report_id *id = hid->driver->report_table;
1464
1465        if (!id) /* NULL means all */
1466                return 1;
1467
1468        for (; id->report_type != HID_TERMINATOR; id++)
1469                if (id->report_type == HID_ANY_ID ||
1470                                id->report_type == report->type)
1471                        return 1;
1472        return 0;
1473}
1474
1475/**
1476 * hid_match_usage - check if driver's event should be called
1477 *
1478 * @hid: hid device
1479 * @usage: usage to match against
1480 *
1481 * compare hid->driver->usage_table->usage_{type,code} to
1482 * usage->usage_{type,code}
1483 */
1484static int hid_match_usage(struct hid_device *hid, struct hid_usage *usage)
1485{
1486        const struct hid_usage_id *id = hid->driver->usage_table;
1487
1488        if (!id) /* NULL means all */
1489                return 1;
1490
1491        for (; id->usage_type != HID_ANY_ID - 1; id++)
1492                if ((id->usage_hid == HID_ANY_ID ||
1493                                id->usage_hid == usage->hid) &&
1494                                (id->usage_type == HID_ANY_ID ||
1495                                id->usage_type == usage->type) &&
1496                                (id->usage_code == HID_ANY_ID ||
1497                                 id->usage_code == usage->code))
1498                        return 1;
1499        return 0;
1500}
1501
1502static void hid_process_event(struct hid_device *hid, struct hid_field *field,
1503                struct hid_usage *usage, __s32 value, int interrupt)
1504{
1505        struct hid_driver *hdrv = hid->driver;
1506        int ret;
1507
1508        if (!list_empty(&hid->debug_list))
1509                hid_dump_input(hid, usage, value);
1510
1511        if (hdrv && hdrv->event && hid_match_usage(hid, usage)) {
1512                ret = hdrv->event(hid, field, usage, value);
1513                if (ret != 0) {
1514                        if (ret < 0)
1515                                hid_err(hid, "%s's event failed with %d\n",
1516                                                hdrv->name, ret);
1517                        return;
1518                }
1519        }
1520
1521        if (hid->claimed & HID_CLAIMED_INPUT)
1522                hidinput_hid_event(hid, field, usage, value);
1523        if (hid->claimed & HID_CLAIMED_HIDDEV && interrupt && hid->hiddev_hid_event)
1524                hid->hiddev_hid_event(hid, field, usage, value);
1525}
1526
1527/*
1528 * Analyse a received field, and fetch the data from it. The field
1529 * content is stored for next report processing (we do differential
1530 * reporting to the layer).
1531 */
1532
1533static void hid_input_field(struct hid_device *hid, struct hid_field *field,
1534                            __u8 *data, int interrupt)
1535{
1536        unsigned n;
1537        unsigned count = field->report_count;
1538        unsigned offset = field->report_offset;
1539        unsigned size = field->report_size;
1540        __s32 min = field->logical_minimum;
1541        __s32 max = field->logical_maximum;
1542        __s32 *value;
1543
1544        value = kmalloc_array(count, sizeof(__s32), GFP_ATOMIC);
1545        if (!value)
1546                return;
1547
1548        for (n = 0; n < count; n++) {
1549
1550                value[n] = min < 0 ?
1551                        snto32(hid_field_extract(hid, data, offset + n * size,
1552                               size), size) :
1553                        hid_field_extract(hid, data, offset + n * size, size);
1554
1555                /* Ignore report if ErrorRollOver */
1556                if (!(field->flags & HID_MAIN_ITEM_VARIABLE) &&
1557                    value[n] >= min && value[n] <= max &&
1558                    value[n] - min < field->maxusage &&
1559                    field->usage[value[n] - min].hid == HID_UP_KEYBOARD + 1)
1560                        goto exit;
1561        }
1562
1563        for (n = 0; n < count; n++) {
1564
1565                if (HID_MAIN_ITEM_VARIABLE & field->flags) {
1566                        hid_process_event(hid, field, &field->usage[n], value[n], interrupt);
1567                        continue;
1568                }
1569
1570                if (field->value[n] >= min && field->value[n] <= max
1571                        && field->value[n] - min < field->maxusage
1572                        && field->usage[field->value[n] - min].hid
1573                        && search(value, field->value[n], count))
1574                                hid_process_event(hid, field, &field->usage[field->value[n] - min], 0, interrupt);
1575
1576                if (value[n] >= min && value[n] <= max
1577                        && value[n] - min < field->maxusage
1578                        && field->usage[value[n] - min].hid
1579                        && search(field->value, value[n], count))
1580                                hid_process_event(hid, field, &field->usage[value[n] - min], 1, interrupt);
1581        }
1582
1583        memcpy(field->value, value, count * sizeof(__s32));
1584exit:
1585        kfree(value);
1586}
1587
1588/*
1589 * Output the field into the report.
1590 */
1591
1592static void hid_output_field(const struct hid_device *hid,
1593                             struct hid_field *field, __u8 *data)
1594{
1595        unsigned count = field->report_count;
1596        unsigned offset = field->report_offset;
1597        unsigned size = field->report_size;
1598        unsigned n;
1599
1600        for (n = 0; n < count; n++) {
1601                if (field->logical_minimum < 0) /* signed values */
1602                        implement(hid, data, offset + n * size, size,
1603                                  s32ton(field->value[n], size));
1604                else                            /* unsigned values */
1605                        implement(hid, data, offset + n * size, size,
1606                                  field->value[n]);
1607        }
1608}
1609
1610/*
1611 * Compute the size of a report.
1612 */
1613static size_t hid_compute_report_size(struct hid_report *report)
1614{
1615        if (report->size)
1616                return ((report->size - 1) >> 3) + 1;
1617
1618        return 0;
1619}
1620
1621/*
1622 * Create a report. 'data' has to be allocated using
1623 * hid_alloc_report_buf() so that it has proper size.
1624 */
1625
1626void hid_output_report(struct hid_report *report, __u8 *data)
1627{
1628        unsigned n;
1629
1630        if (report->id > 0)
1631                *data++ = report->id;
1632
1633        memset(data, 0, hid_compute_report_size(report));
1634        for (n = 0; n < report->maxfield; n++)
1635                hid_output_field(report->device, report->field[n], data);
1636}
1637EXPORT_SYMBOL_GPL(hid_output_report);
1638
1639/*
1640 * Allocator for buffer that is going to be passed to hid_output_report()
1641 */
1642u8 *hid_alloc_report_buf(struct hid_report *report, gfp_t flags)
1643{
1644        /*
1645         * 7 extra bytes are necessary to achieve proper functionality
1646         * of implement() working on 8 byte chunks
1647         */
1648
1649        u32 len = hid_report_len(report) + 7;
1650
1651        return kmalloc(len, flags);
1652}
1653EXPORT_SYMBOL_GPL(hid_alloc_report_buf);
1654
1655/*
1656 * Set a field value. The report this field belongs to has to be
1657 * created and transferred to the device, to set this value in the
1658 * device.
1659 */
1660
1661int hid_set_field(struct hid_field *field, unsigned offset, __s32 value)
1662{
1663        unsigned size;
1664
1665        if (!field)
1666                return -1;
1667
1668        size = field->report_size;
1669
1670        hid_dump_input(field->report->device, field->usage + offset, value);
1671
1672        if (offset >= field->report_count) {
1673                hid_err(field->report->device, "offset (%d) exceeds report_count (%d)\n",
1674                                offset, field->report_count);
1675                return -1;
1676        }
1677        if (field->logical_minimum < 0) {
1678                if (value != snto32(s32ton(value, size), size)) {
1679                        hid_err(field->report->device, "value %d is out of range\n", value);
1680                        return -1;
1681                }
1682        }
1683        field->value[offset] = value;
1684        return 0;
1685}
1686EXPORT_SYMBOL_GPL(hid_set_field);
1687
1688static struct hid_report *hid_get_report(struct hid_report_enum *report_enum,
1689                const u8 *data)
1690{
1691        struct hid_report *report;
1692        unsigned int n = 0;     /* Normally report number is 0 */
1693
1694        /* Device uses numbered reports, data[0] is report number */
1695        if (report_enum->numbered)
1696                n = *data;
1697
1698        report = report_enum->report_id_hash[n];
1699        if (report == NULL)
1700                dbg_hid("undefined report_id %u received\n", n);
1701
1702        return report;
1703}
1704
1705/*
1706 * Implement a generic .request() callback, using .raw_request()
1707 * DO NOT USE in hid drivers directly, but through hid_hw_request instead.
1708 */
1709int __hid_request(struct hid_device *hid, struct hid_report *report,
1710                int reqtype)
1711{
1712        char *buf;
1713        int ret;
1714        u32 len;
1715
1716        buf = hid_alloc_report_buf(report, GFP_KERNEL);
1717        if (!buf)
1718                return -ENOMEM;
1719
1720        len = hid_report_len(report);
1721
1722        if (reqtype == HID_REQ_SET_REPORT)
1723                hid_output_report(report, buf);
1724
1725        ret = hid->ll_driver->raw_request(hid, report->id, buf, len,
1726                                          report->type, reqtype);
1727        if (ret < 0) {
1728                dbg_hid("unable to complete request: %d\n", ret);
1729                goto out;
1730        }
1731
1732        if (reqtype == HID_REQ_GET_REPORT)
1733                hid_input_report(hid, report->type, buf, ret, 0);
1734
1735        ret = 0;
1736
1737out:
1738        kfree(buf);
1739        return ret;
1740}
1741EXPORT_SYMBOL_GPL(__hid_request);
1742
1743int hid_report_raw_event(struct hid_device *hid, int type, u8 *data, u32 size,
1744                int interrupt)
1745{
1746        struct hid_report_enum *report_enum = hid->report_enum + type;
1747        struct hid_report *report;
1748        struct hid_driver *hdrv;
1749        unsigned int a;
1750        u32 rsize, csize = size;
1751        u8 *cdata = data;
1752        int ret = 0;
1753
1754        report = hid_get_report(report_enum, data);
1755        if (!report)
1756                goto out;
1757
1758        if (report_enum->numbered) {
1759                cdata++;
1760                csize--;
1761        }
1762
1763        rsize = hid_compute_report_size(report);
1764
1765        if (report_enum->numbered && rsize >= HID_MAX_BUFFER_SIZE)
1766                rsize = HID_MAX_BUFFER_SIZE - 1;
1767        else if (rsize > HID_MAX_BUFFER_SIZE)
1768                rsize = HID_MAX_BUFFER_SIZE;
1769
1770        if (csize < rsize) {
1771                dbg_hid("report %d is too short, (%d < %d)\n", report->id,
1772                                csize, rsize);
1773                memset(cdata + csize, 0, rsize - csize);
1774        }
1775
1776        if ((hid->claimed & HID_CLAIMED_HIDDEV) && hid->hiddev_report_event)
1777                hid->hiddev_report_event(hid, report);
1778        if (hid->claimed & HID_CLAIMED_HIDRAW) {
1779                ret = hidraw_report_event(hid, data, size);
1780                if (ret)
1781                        goto out;
1782        }
1783
1784        if (hid->claimed != HID_CLAIMED_HIDRAW && report->maxfield) {
1785                for (a = 0; a < report->maxfield; a++)
1786                        hid_input_field(hid, report->field[a], cdata, interrupt);
1787                hdrv = hid->driver;
1788                if (hdrv && hdrv->report)
1789                        hdrv->report(hid, report);
1790        }
1791
1792        if (hid->claimed & HID_CLAIMED_INPUT)
1793                hidinput_report_event(hid, report);
1794out:
1795        return ret;
1796}
1797EXPORT_SYMBOL_GPL(hid_report_raw_event);
1798
1799/**
1800 * hid_input_report - report data from lower layer (usb, bt...)
1801 *
1802 * @hid: hid device
1803 * @type: HID report type (HID_*_REPORT)
1804 * @data: report contents
1805 * @size: size of data parameter
1806 * @interrupt: distinguish between interrupt and control transfers
1807 *
1808 * This is data entry for lower layers.
1809 */
1810int hid_input_report(struct hid_device *hid, int type, u8 *data, u32 size, int interrupt)
1811{
1812        struct hid_report_enum *report_enum;
1813        struct hid_driver *hdrv;
1814        struct hid_report *report;
1815        int ret = 0;
1816
1817        if (!hid)
1818                return -ENODEV;
1819
1820        if (down_trylock(&hid->driver_input_lock))
1821                return -EBUSY;
1822
1823        if (!hid->driver) {
1824                ret = -ENODEV;
1825                goto unlock;
1826        }
1827        report_enum = hid->report_enum + type;
1828        hdrv = hid->driver;
1829
1830        if (!size) {
1831                dbg_hid("empty report\n");
1832                ret = -1;
1833                goto unlock;
1834        }
1835
1836        /* Avoid unnecessary overhead if debugfs is disabled */
1837        if (!list_empty(&hid->debug_list))
1838                hid_dump_report(hid, type, data, size);
1839
1840        report = hid_get_report(report_enum, data);
1841
1842        if (!report) {
1843                ret = -1;
1844                goto unlock;
1845        }
1846
1847        if (hdrv && hdrv->raw_event && hid_match_report(hid, report)) {
1848                ret = hdrv->raw_event(hid, report, data, size);
1849                if (ret < 0)
1850                        goto unlock;
1851        }
1852
1853        ret = hid_report_raw_event(hid, type, data, size, interrupt);
1854
1855unlock:
1856        up(&hid->driver_input_lock);
1857        return ret;
1858}
1859EXPORT_SYMBOL_GPL(hid_input_report);
1860
1861bool hid_match_one_id(const struct hid_device *hdev,
1862                      const struct hid_device_id *id)
1863{
1864        return (id->bus == HID_BUS_ANY || id->bus == hdev->bus) &&
1865                (id->group == HID_GROUP_ANY || id->group == hdev->group) &&
1866                (id->vendor == HID_ANY_ID || id->vendor == hdev->vendor) &&
1867                (id->product == HID_ANY_ID || id->product == hdev->product);
1868}
1869
1870const struct hid_device_id *hid_match_id(const struct hid_device *hdev,
1871                const struct hid_device_id *id)
1872{
1873        for (; id->bus; id++)
1874                if (hid_match_one_id(hdev, id))
1875                        return id;
1876
1877        return NULL;
1878}
1879
1880static const struct hid_device_id hid_hiddev_list[] = {
1881        { HID_USB_DEVICE(USB_VENDOR_ID_MGE, USB_DEVICE_ID_MGE_UPS) },
1882        { HID_USB_DEVICE(USB_VENDOR_ID_MGE, USB_DEVICE_ID_MGE_UPS1) },
1883        { }
1884};
1885
1886static bool hid_hiddev(struct hid_device *hdev)
1887{
1888        return !!hid_match_id(hdev, hid_hiddev_list);
1889}
1890
1891
1892static ssize_t
1893read_report_descriptor(struct file *filp, struct kobject *kobj,
1894                struct bin_attribute *attr,
1895                char *buf, loff_t off, size_t count)
1896{
1897        struct device *dev = kobj_to_dev(kobj);
1898        struct hid_device *hdev = to_hid_device(dev);
1899
1900        if (off >= hdev->rsize)
1901                return 0;
1902
1903        if (off + count > hdev->rsize)
1904                count = hdev->rsize - off;
1905
1906        memcpy(buf, hdev->rdesc + off, count);
1907
1908        return count;
1909}
1910
1911static ssize_t
1912show_country(struct device *dev, struct device_attribute *attr,
1913                char *buf)
1914{
1915        struct hid_device *hdev = to_hid_device(dev);
1916
1917        return sprintf(buf, "%02x\n", hdev->country & 0xff);
1918}
1919
1920static struct bin_attribute dev_bin_attr_report_desc = {
1921        .attr = { .name = "report_descriptor", .mode = 0444 },
1922        .read = read_report_descriptor,
1923        .size = HID_MAX_DESCRIPTOR_SIZE,
1924};
1925
1926static const struct device_attribute dev_attr_country = {
1927        .attr = { .name = "country", .mode = 0444 },
1928        .show = show_country,
1929};
1930
1931int hid_connect(struct hid_device *hdev, unsigned int connect_mask)
1932{
1933        static const char *types[] = { "Device", "Pointer", "Mouse", "Device",
1934                "Joystick", "Gamepad", "Keyboard", "Keypad",
1935                "Multi-Axis Controller"
1936        };
1937        const char *type, *bus;
1938        char buf[64] = "";
1939        unsigned int i;
1940        int len;
1941        int ret;
1942
1943        if (hdev->quirks & HID_QUIRK_HIDDEV_FORCE)
1944                connect_mask |= (HID_CONNECT_HIDDEV_FORCE | HID_CONNECT_HIDDEV);
1945        if (hdev->quirks & HID_QUIRK_HIDINPUT_FORCE)
1946                connect_mask |= HID_CONNECT_HIDINPUT_FORCE;
1947        if (hdev->bus != BUS_USB)
1948                connect_mask &= ~HID_CONNECT_HIDDEV;
1949        if (hid_hiddev(hdev))
1950                connect_mask |= HID_CONNECT_HIDDEV_FORCE;
1951
1952        if ((connect_mask & HID_CONNECT_HIDINPUT) && !hidinput_connect(hdev,
1953                                connect_mask & HID_CONNECT_HIDINPUT_FORCE))
1954                hdev->claimed |= HID_CLAIMED_INPUT;
1955
1956        if ((connect_mask & HID_CONNECT_HIDDEV) && hdev->hiddev_connect &&
1957                        !hdev->hiddev_connect(hdev,
1958                                connect_mask & HID_CONNECT_HIDDEV_FORCE))
1959                hdev->claimed |= HID_CLAIMED_HIDDEV;
1960        if ((connect_mask & HID_CONNECT_HIDRAW) && !hidraw_connect(hdev))
1961                hdev->claimed |= HID_CLAIMED_HIDRAW;
1962
1963        if (connect_mask & HID_CONNECT_DRIVER)
1964                hdev->claimed |= HID_CLAIMED_DRIVER;
1965
1966        /* Drivers with the ->raw_event callback set are not required to connect
1967         * to any other listener. */
1968        if (!hdev->claimed && !hdev->driver->raw_event) {
1969                hid_err(hdev, "device has no listeners, quitting\n");
1970                return -ENODEV;
1971        }
1972
1973        if ((hdev->claimed & HID_CLAIMED_INPUT) &&
1974                        (connect_mask & HID_CONNECT_FF) && hdev->ff_init)
1975                hdev->ff_init(hdev);
1976
1977        len = 0;
1978        if (hdev->claimed & HID_CLAIMED_INPUT)
1979                len += sprintf(buf + len, "input");
1980        if (hdev->claimed & HID_CLAIMED_HIDDEV)
1981                len += sprintf(buf + len, "%shiddev%d", len ? "," : "",
1982                                ((struct hiddev *)hdev->hiddev)->minor);
1983        if (hdev->claimed & HID_CLAIMED_HIDRAW)
1984                len += sprintf(buf + len, "%shidraw%d", len ? "," : "",
1985                                ((struct hidraw *)hdev->hidraw)->minor);
1986
1987        type = "Device";
1988        for (i = 0; i < hdev->maxcollection; i++) {
1989                struct hid_collection *col = &hdev->collection[i];
1990                if (col->type == HID_COLLECTION_APPLICATION &&
1991                   (col->usage & HID_USAGE_PAGE) == HID_UP_GENDESK &&
1992                   (col->usage & 0xffff) < ARRAY_SIZE(types)) {
1993                        type = types[col->usage & 0xffff];
1994                        break;
1995                }
1996        }
1997
1998        switch (hdev->bus) {
1999        case BUS_USB:
2000                bus = "USB";
2001                break;
2002        case BUS_BLUETOOTH:
2003                bus = "BLUETOOTH";
2004                break;
2005        case BUS_I2C:
2006                bus = "I2C";
2007                break;
2008        case BUS_VIRTUAL:
2009                bus = "VIRTUAL";
2010                break;
2011        default:
2012                bus = "<UNKNOWN>";
2013        }
2014
2015        ret = device_create_file(&hdev->dev, &dev_attr_country);
2016        if (ret)
2017                hid_warn(hdev,
2018                         "can't create sysfs country code attribute err: %d\n", ret);
2019
2020        hid_info(hdev, "%s: %s HID v%x.%02x %s [%s] on %s\n",
2021                 buf, bus, hdev->version >> 8, hdev->version & 0xff,
2022                 type, hdev->name, hdev->phys);
2023
2024        return 0;
2025}
2026EXPORT_SYMBOL_GPL(hid_connect);
2027
2028void hid_disconnect(struct hid_device *hdev)
2029{
2030        device_remove_file(&hdev->dev, &dev_attr_country);
2031        if (hdev->claimed & HID_CLAIMED_INPUT)
2032                hidinput_disconnect(hdev);
2033        if (hdev->claimed & HID_CLAIMED_HIDDEV)
2034                hdev->hiddev_disconnect(hdev);
2035        if (hdev->claimed & HID_CLAIMED_HIDRAW)
2036                hidraw_disconnect(hdev);
2037        hdev->claimed = 0;
2038}
2039EXPORT_SYMBOL_GPL(hid_disconnect);
2040
2041/**
2042 * hid_hw_start - start underlying HW
2043 * @hdev: hid device
2044 * @connect_mask: which outputs to connect, see HID_CONNECT_*
2045 *
2046 * Call this in probe function *after* hid_parse. This will setup HW
2047 * buffers and start the device (if not defeirred to device open).
2048 * hid_hw_stop must be called if this was successful.
2049 */
2050int hid_hw_start(struct hid_device *hdev, unsigned int connect_mask)
2051{
2052        int error;
2053
2054        error = hdev->ll_driver->start(hdev);
2055        if (error)
2056                return error;
2057
2058        if (connect_mask) {
2059                error = hid_connect(hdev, connect_mask);
2060                if (error) {
2061                        hdev->ll_driver->stop(hdev);
2062                        return error;
2063                }
2064        }
2065
2066        return 0;
2067}
2068EXPORT_SYMBOL_GPL(hid_hw_start);
2069
2070/**
2071 * hid_hw_stop - stop underlying HW
2072 * @hdev: hid device
2073 *
2074 * This is usually called from remove function or from probe when something
2075 * failed and hid_hw_start was called already.
2076 */
2077void hid_hw_stop(struct hid_device *hdev)
2078{
2079        hid_disconnect(hdev);
2080        hdev->ll_driver->stop(hdev);
2081}
2082EXPORT_SYMBOL_GPL(hid_hw_stop);
2083
2084/**
2085 * hid_hw_open - signal underlying HW to start delivering events
2086 * @hdev: hid device
2087 *
2088 * Tell underlying HW to start delivering events from the device.
2089 * This function should be called sometime after successful call
2090 * to hid_hw_start().
2091 */
2092int hid_hw_open(struct hid_device *hdev)
2093{
2094        int ret;
2095
2096        ret = mutex_lock_killable(&hdev->ll_open_lock);
2097        if (ret)
2098                return ret;
2099
2100        if (!hdev->ll_open_count++) {
2101                ret = hdev->ll_driver->open(hdev);
2102                if (ret)
2103                        hdev->ll_open_count--;
2104        }
2105
2106        mutex_unlock(&hdev->ll_open_lock);
2107        return ret;
2108}
2109EXPORT_SYMBOL_GPL(hid_hw_open);
2110
2111/**
2112 * hid_hw_close - signal underlaying HW to stop delivering events
2113 *
2114 * @hdev: hid device
2115 *
2116 * This function indicates that we are not interested in the events
2117 * from this device anymore. Delivery of events may or may not stop,
2118 * depending on the number of users still outstanding.
2119 */
2120void hid_hw_close(struct hid_device *hdev)
2121{
2122        mutex_lock(&hdev->ll_open_lock);
2123        if (!--hdev->ll_open_count)
2124                hdev->ll_driver->close(hdev);
2125        mutex_unlock(&hdev->ll_open_lock);
2126}
2127EXPORT_SYMBOL_GPL(hid_hw_close);
2128
2129struct hid_dynid {
2130        struct list_head list;
2131        struct hid_device_id id;
2132};
2133
2134/**
2135 * new_id_store - add a new HID device ID to this driver and re-probe devices
2136 * @drv: target device driver
2137 * @buf: buffer for scanning device ID data
2138 * @count: input size
2139 *
2140 * Adds a new dynamic hid device ID to this driver,
2141 * and causes the driver to probe for all devices again.
2142 */
2143static ssize_t new_id_store(struct device_driver *drv, const char *buf,
2144                size_t count)
2145{
2146        struct hid_driver *hdrv = to_hid_driver(drv);
2147        struct hid_dynid *dynid;
2148        __u32 bus, vendor, product;
2149        unsigned long driver_data = 0;
2150        int ret;
2151
2152        ret = sscanf(buf, "%x %x %x %lx",
2153                        &bus, &vendor, &product, &driver_data);
2154        if (ret < 3)
2155                return -EINVAL;
2156
2157        dynid = kzalloc(sizeof(*dynid), GFP_KERNEL);
2158        if (!dynid)
2159                return -ENOMEM;
2160
2161        dynid->id.bus = bus;
2162        dynid->id.group = HID_GROUP_ANY;
2163        dynid->id.vendor = vendor;
2164        dynid->id.product = product;
2165        dynid->id.driver_data = driver_data;
2166
2167        spin_lock(&hdrv->dyn_lock);
2168        list_add_tail(&dynid->list, &hdrv->dyn_list);
2169        spin_unlock(&hdrv->dyn_lock);
2170
2171        ret = driver_attach(&hdrv->driver);
2172
2173        return ret ? : count;
2174}
2175static DRIVER_ATTR_WO(new_id);
2176
2177static struct attribute *hid_drv_attrs[] = {
2178        &driver_attr_new_id.attr,
2179        NULL,
2180};
2181ATTRIBUTE_GROUPS(hid_drv);
2182
2183static void hid_free_dynids(struct hid_driver *hdrv)
2184{
2185        struct hid_dynid *dynid, *n;
2186
2187        spin_lock(&hdrv->dyn_lock);
2188        list_for_each_entry_safe(dynid, n, &hdrv->dyn_list, list) {
2189                list_del(&dynid->list);
2190                kfree(dynid);
2191        }
2192        spin_unlock(&hdrv->dyn_lock);
2193}
2194
2195const struct hid_device_id *hid_match_device(struct hid_device *hdev,
2196                                             struct hid_driver *hdrv)
2197{
2198        struct hid_dynid *dynid;
2199
2200        spin_lock(&hdrv->dyn_lock);
2201        list_for_each_entry(dynid, &hdrv->dyn_list, list) {
2202                if (hid_match_one_id(hdev, &dynid->id)) {
2203                        spin_unlock(&hdrv->dyn_lock);
2204                        return &dynid->id;
2205                }
2206        }
2207        spin_unlock(&hdrv->dyn_lock);
2208
2209        return hid_match_id(hdev, hdrv->id_table);
2210}
2211EXPORT_SYMBOL_GPL(hid_match_device);
2212
2213static int hid_bus_match(struct device *dev, struct device_driver *drv)
2214{
2215        struct hid_driver *hdrv = to_hid_driver(drv);
2216        struct hid_device *hdev = to_hid_device(dev);
2217
2218        return hid_match_device(hdev, hdrv) != NULL;
2219}
2220
2221/**
2222 * hid_compare_device_paths - check if both devices share the same path
2223 * @hdev_a: hid device
2224 * @hdev_b: hid device
2225 * @separator: char to use as separator
2226 *
2227 * Check if two devices share the same path up to the last occurrence of
2228 * the separator char. Both paths must exist (i.e., zero-length paths
2229 * don't match).
2230 */
2231bool hid_compare_device_paths(struct hid_device *hdev_a,
2232                              struct hid_device *hdev_b, char separator)
2233{
2234        int n1 = strrchr(hdev_a->phys, separator) - hdev_a->phys;
2235        int n2 = strrchr(hdev_b->phys, separator) - hdev_b->phys;
2236
2237        if (n1 != n2 || n1 <= 0 || n2 <= 0)
2238                return false;
2239
2240        return !strncmp(hdev_a->phys, hdev_b->phys, n1);
2241}
2242EXPORT_SYMBOL_GPL(hid_compare_device_paths);
2243
2244static int hid_device_probe(struct device *dev)
2245{
2246        struct hid_driver *hdrv = to_hid_driver(dev->driver);
2247        struct hid_device *hdev = to_hid_device(dev);
2248        const struct hid_device_id *id;
2249        int ret = 0;
2250
2251        if (down_interruptible(&hdev->driver_input_lock)) {
2252                ret = -EINTR;
2253                goto end;
2254        }
2255        hdev->io_started = false;
2256
2257        clear_bit(ffs(HID_STAT_REPROBED), &hdev->status);
2258
2259        if (!hdev->driver) {
2260                id = hid_match_device(hdev, hdrv);
2261                if (id == NULL) {
2262                        ret = -ENODEV;
2263                        goto unlock;
2264                }
2265
2266                if (hdrv->match) {
2267                        if (!hdrv->match(hdev, hid_ignore_special_drivers)) {
2268                                ret = -ENODEV;
2269                                goto unlock;
2270                        }
2271                } else {
2272                        /*
2273                         * hid-generic implements .match(), so if
2274                         * hid_ignore_special_drivers is set, we can safely
2275                         * return.
2276                         */
2277                        if (hid_ignore_special_drivers) {
2278                                ret = -ENODEV;
2279                                goto unlock;
2280                        }
2281                }
2282
2283                /* reset the quirks that has been previously set */
2284                hdev->quirks = hid_lookup_quirk(hdev);
2285                hdev->driver = hdrv;
2286                if (hdrv->probe) {
2287                        ret = hdrv->probe(hdev, id);
2288                } else { /* default probe */
2289                        ret = hid_open_report(hdev);
2290                        if (!ret)
2291                                ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
2292                }
2293                if (ret) {
2294                        hid_close_report(hdev);
2295                        hdev->driver = NULL;
2296                }
2297        }
2298unlock:
2299        if (!hdev->io_started)
2300                up(&hdev->driver_input_lock);
2301end:
2302        return ret;
2303}
2304
2305static int hid_device_remove(struct device *dev)
2306{
2307        struct hid_device *hdev = to_hid_device(dev);
2308        struct hid_driver *hdrv;
2309
2310        down(&hdev->driver_input_lock);
2311        hdev->io_started = false;
2312
2313        hdrv = hdev->driver;
2314        if (hdrv) {
2315                if (hdrv->remove)
2316                        hdrv->remove(hdev);
2317                else /* default remove */
2318                        hid_hw_stop(hdev);
2319                hid_close_report(hdev);
2320                hdev->driver = NULL;
2321        }
2322
2323        if (!hdev->io_started)
2324                up(&hdev->driver_input_lock);
2325
2326        return 0;
2327}
2328
2329static ssize_t modalias_show(struct device *dev, struct device_attribute *a,
2330                             char *buf)
2331{
2332        struct hid_device *hdev = container_of(dev, struct hid_device, dev);
2333
2334        return scnprintf(buf, PAGE_SIZE, "hid:b%04Xg%04Xv%08Xp%08X\n",
2335                         hdev->bus, hdev->group, hdev->vendor, hdev->product);
2336}
2337static DEVICE_ATTR_RO(modalias);
2338
2339static struct attribute *hid_dev_attrs[] = {
2340        &dev_attr_modalias.attr,
2341        NULL,
2342};
2343static struct bin_attribute *hid_dev_bin_attrs[] = {
2344        &dev_bin_attr_report_desc,
2345        NULL
2346};
2347static const struct attribute_group hid_dev_group = {
2348        .attrs = hid_dev_attrs,
2349        .bin_attrs = hid_dev_bin_attrs,
2350};
2351__ATTRIBUTE_GROUPS(hid_dev);
2352
2353static int hid_uevent(struct device *dev, struct kobj_uevent_env *env)
2354{
2355        struct hid_device *hdev = to_hid_device(dev);
2356
2357        if (add_uevent_var(env, "HID_ID=%04X:%08X:%08X",
2358                        hdev->bus, hdev->vendor, hdev->product))
2359                return -ENOMEM;
2360
2361        if (add_uevent_var(env, "HID_NAME=%s", hdev->name))
2362                return -ENOMEM;
2363
2364        if (add_uevent_var(env, "HID_PHYS=%s", hdev->phys))
2365                return -ENOMEM;
2366
2367        if (add_uevent_var(env, "HID_UNIQ=%s", hdev->uniq))
2368                return -ENOMEM;
2369
2370        if (add_uevent_var(env, "MODALIAS=hid:b%04Xg%04Xv%08Xp%08X",
2371                           hdev->bus, hdev->group, hdev->vendor, hdev->product))
2372                return -ENOMEM;
2373
2374        return 0;
2375}
2376
2377struct bus_type hid_bus_type = {
2378        .name           = "hid",
2379        .dev_groups     = hid_dev_groups,
2380        .drv_groups     = hid_drv_groups,
2381        .match          = hid_bus_match,
2382        .probe          = hid_device_probe,
2383        .remove         = hid_device_remove,
2384        .uevent         = hid_uevent,
2385};
2386EXPORT_SYMBOL(hid_bus_type);
2387
2388int hid_add_device(struct hid_device *hdev)
2389{
2390        static atomic_t id = ATOMIC_INIT(0);
2391        int ret;
2392
2393        if (WARN_ON(hdev->status & HID_STAT_ADDED))
2394                return -EBUSY;
2395
2396        hdev->quirks = hid_lookup_quirk(hdev);
2397
2398        /* we need to kill them here, otherwise they will stay allocated to
2399         * wait for coming driver */
2400        if (hid_ignore(hdev))
2401                return -ENODEV;
2402
2403        /*
2404         * Check for the mandatory transport channel.
2405         */
2406         if (!hdev->ll_driver->raw_request) {
2407                hid_err(hdev, "transport driver missing .raw_request()\n");
2408                return -EINVAL;
2409         }
2410
2411        /*
2412         * Read the device report descriptor once and use as template
2413         * for the driver-specific modifications.
2414         */
2415        ret = hdev->ll_driver->parse(hdev);
2416        if (ret)
2417                return ret;
2418        if (!hdev->dev_rdesc)
2419                return -ENODEV;
2420
2421        /*
2422         * Scan generic devices for group information
2423         */
2424        if (hid_ignore_special_drivers) {
2425                hdev->group = HID_GROUP_GENERIC;
2426        } else if (!hdev->group &&
2427                   !(hdev->quirks & HID_QUIRK_HAVE_SPECIAL_DRIVER)) {
2428                ret = hid_scan_report(hdev);
2429                if (ret)
2430                        hid_warn(hdev, "bad device descriptor (%d)\n", ret);
2431        }
2432
2433        /* XXX hack, any other cleaner solution after the driver core
2434         * is converted to allow more than 20 bytes as the device name? */
2435        dev_set_name(&hdev->dev, "%04X:%04X:%04X.%04X", hdev->bus,
2436                     hdev->vendor, hdev->product, atomic_inc_return(&id));
2437
2438        hid_debug_register(hdev, dev_name(&hdev->dev));
2439        ret = device_add(&hdev->dev);
2440        if (!ret)
2441                hdev->status |= HID_STAT_ADDED;
2442        else
2443                hid_debug_unregister(hdev);
2444
2445        return ret;
2446}
2447EXPORT_SYMBOL_GPL(hid_add_device);
2448
2449/**
2450 * hid_allocate_device - allocate new hid device descriptor
2451 *
2452 * Allocate and initialize hid device, so that hid_destroy_device might be
2453 * used to free it.
2454 *
2455 * New hid_device pointer is returned on success, otherwise ERR_PTR encoded
2456 * error value.
2457 */
2458struct hid_device *hid_allocate_device(void)
2459{
2460        struct hid_device *hdev;
2461        int ret = -ENOMEM;
2462
2463        hdev = kzalloc(sizeof(*hdev), GFP_KERNEL);
2464        if (hdev == NULL)
2465                return ERR_PTR(ret);
2466
2467        device_initialize(&hdev->dev);
2468        hdev->dev.release = hid_device_release;
2469        hdev->dev.bus = &hid_bus_type;
2470        device_enable_async_suspend(&hdev->dev);
2471
2472        hid_close_report(hdev);
2473
2474        init_waitqueue_head(&hdev->debug_wait);
2475        INIT_LIST_HEAD(&hdev->debug_list);
2476        spin_lock_init(&hdev->debug_list_lock);
2477        sema_init(&hdev->driver_input_lock, 1);
2478        mutex_init(&hdev->ll_open_lock);
2479
2480        return hdev;
2481}
2482EXPORT_SYMBOL_GPL(hid_allocate_device);
2483
2484static void hid_remove_device(struct hid_device *hdev)
2485{
2486        if (hdev->status & HID_STAT_ADDED) {
2487                device_del(&hdev->dev);
2488                hid_debug_unregister(hdev);
2489                hdev->status &= ~HID_STAT_ADDED;
2490        }
2491        kfree(hdev->dev_rdesc);
2492        hdev->dev_rdesc = NULL;
2493        hdev->dev_rsize = 0;
2494}
2495
2496/**
2497 * hid_destroy_device - free previously allocated device
2498 *
2499 * @hdev: hid device
2500 *
2501 * If you allocate hid_device through hid_allocate_device, you should ever
2502 * free by this function.
2503 */
2504void hid_destroy_device(struct hid_device *hdev)
2505{
2506        hid_remove_device(hdev);
2507        put_device(&hdev->dev);
2508}
2509EXPORT_SYMBOL_GPL(hid_destroy_device);
2510
2511
2512static int __hid_bus_reprobe_drivers(struct device *dev, void *data)
2513{
2514        struct hid_driver *hdrv = data;
2515        struct hid_device *hdev = to_hid_device(dev);
2516
2517        if (hdev->driver == hdrv &&
2518            !hdrv->match(hdev, hid_ignore_special_drivers) &&
2519            !test_and_set_bit(ffs(HID_STAT_REPROBED), &hdev->status))
2520                return device_reprobe(dev);
2521
2522        return 0;
2523}
2524
2525static int __hid_bus_driver_added(struct device_driver *drv, void *data)
2526{
2527        struct hid_driver *hdrv = to_hid_driver(drv);
2528
2529        if (hdrv->match) {
2530                bus_for_each_dev(&hid_bus_type, NULL, hdrv,
2531                                 __hid_bus_reprobe_drivers);
2532        }
2533
2534        return 0;
2535}
2536
2537static int __bus_removed_driver(struct device_driver *drv, void *data)
2538{
2539        return bus_rescan_devices(&hid_bus_type);
2540}
2541
2542int __hid_register_driver(struct hid_driver *hdrv, struct module *owner,
2543                const char *mod_name)
2544{
2545        int ret;
2546
2547        hdrv->driver.name = hdrv->name;
2548        hdrv->driver.bus = &hid_bus_type;
2549        hdrv->driver.owner = owner;
2550        hdrv->driver.mod_name = mod_name;
2551
2552        INIT_LIST_HEAD(&hdrv->dyn_list);
2553        spin_lock_init(&hdrv->dyn_lock);
2554
2555        ret = driver_register(&hdrv->driver);
2556
2557        if (ret == 0)
2558                bus_for_each_drv(&hid_bus_type, NULL, NULL,
2559                                 __hid_bus_driver_added);
2560
2561        return ret;
2562}
2563EXPORT_SYMBOL_GPL(__hid_register_driver);
2564
2565void hid_unregister_driver(struct hid_driver *hdrv)
2566{
2567        driver_unregister(&hdrv->driver);
2568        hid_free_dynids(hdrv);
2569
2570        bus_for_each_drv(&hid_bus_type, NULL, hdrv, __bus_removed_driver);
2571}
2572EXPORT_SYMBOL_GPL(hid_unregister_driver);
2573
2574int hid_check_keys_pressed(struct hid_device *hid)
2575{
2576        struct hid_input *hidinput;
2577        int i;
2578
2579        if (!(hid->claimed & HID_CLAIMED_INPUT))
2580                return 0;
2581
2582        list_for_each_entry(hidinput, &hid->inputs, list) {
2583                for (i = 0; i < BITS_TO_LONGS(KEY_MAX); i++)
2584                        if (hidinput->input->key[i])
2585                                return 1;
2586        }
2587
2588        return 0;
2589}
2590EXPORT_SYMBOL_GPL(hid_check_keys_pressed);
2591
2592static int __init hid_init(void)
2593{
2594        int ret;
2595
2596        if (hid_debug)
2597                pr_warn("hid_debug is now used solely for parser and driver debugging.\n"
2598                        "debugfs is now used for inspecting the device (report descriptor, reports)\n");
2599
2600        ret = bus_register(&hid_bus_type);
2601        if (ret) {
2602                pr_err("can't register hid bus\n");
2603                goto err;
2604        }
2605
2606        ret = hidraw_init();
2607        if (ret)
2608                goto err_bus;
2609
2610        hid_debug_init();
2611
2612        return 0;
2613err_bus:
2614        bus_unregister(&hid_bus_type);
2615err:
2616        return ret;
2617}
2618
2619static void __exit hid_exit(void)
2620{
2621        hid_debug_exit();
2622        hidraw_exit();
2623        bus_unregister(&hid_bus_type);
2624        hid_quirks_exit(HID_BUS_ANY);
2625}
2626
2627module_init(hid_init);
2628module_exit(hid_exit);
2629
2630MODULE_AUTHOR("Andreas Gal");
2631MODULE_AUTHOR("Vojtech Pavlik");
2632MODULE_AUTHOR("Jiri Kosina");
2633MODULE_LICENSE("GPL");
2634
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