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hid-core.c

/*
 *  HID support for Linux
 *
 *  Copyright (c) 1999 Andreas Gal
 *  Copyright (c) 2000-2005 Vojtech Pavlik <vojtech@suse.cz>
 *  Copyright (c) 2005 Michael Haboustak <mike-@cinci.rr.com> for Concept2, Inc
 *  Copyright (c) 2006-2007 Jiri Kosina
 */

/*
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 2 of the License, or (at your option)
 * any later version.
 */

#include <linux/module.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/mm.h>
#include <linux/spinlock.h>
#include <asm/unaligned.h>
#include <asm/byteorder.h>
#include <linux/input.h>
#include <linux/wait.h>
#include <linux/vmalloc.h>

#include <linux/hid.h>
#include <linux/hiddev.h>
#include <linux/hid-debug.h>
#include <linux/hidraw.h>

/*
 * Version Information
 */

#define DRIVER_VERSION "v2.6"
#define DRIVER_AUTHOR "Andreas Gal, Vojtech Pavlik, Jiri Kosina"
#define DRIVER_DESC "HID core driver"
#define DRIVER_LICENSE "GPL"

#ifdef CONFIG_HID_DEBUG
int hid_debug = 0;
module_param_named(debug, hid_debug, bool, 0600);
MODULE_PARM_DESC(debug, "Turn HID debugging mode on and off");
EXPORT_SYMBOL_GPL(hid_debug);
#endif

/*
 * Register a new report for a device.
 */

static struct hid_report *hid_register_report(struct hid_device *device, unsigned type, unsigned id)
{
      struct hid_report_enum *report_enum = device->report_enum + type;
      struct hid_report *report;

      if (report_enum->report_id_hash[id])
            return report_enum->report_id_hash[id];

      if (!(report = kzalloc(sizeof(struct hid_report), GFP_KERNEL)))
            return NULL;

      if (id != 0)
            report_enum->numbered = 1;

      report->id = id;
      report->type = type;
      report->size = 0;
      report->device = device;
      report_enum->report_id_hash[id] = report;

      list_add_tail(&report->list, &report_enum->report_list);

      return report;
}

/*
 * Register a new field for this report.
 */

static struct hid_field *hid_register_field(struct hid_report *report, unsigned usages, unsigned values)
{
      struct hid_field *field;

      if (report->maxfield == HID_MAX_FIELDS) {
            dbg_hid("too many fields in report\n");
            return NULL;
      }

      if (!(field = kzalloc(sizeof(struct hid_field) + usages * sizeof(struct hid_usage)
            + values * sizeof(unsigned), GFP_KERNEL))) return NULL;

      field->index = report->maxfield++;
      report->field[field->index] = field;
      field->usage = (struct hid_usage *)(field + 1);
      field->value = (unsigned *)(field->usage + usages);
      field->report = report;

      return field;
}

/*
 * Open a collection. The type/usage is pushed on the stack.
 */

static int open_collection(struct hid_parser *parser, unsigned type)
{
      struct hid_collection *collection;
      unsigned usage;

      usage = parser->local.usage[0];

      if (parser->collection_stack_ptr == HID_COLLECTION_STACK_SIZE) {
            dbg_hid("collection stack overflow\n");
            return -1;
      }

      if (parser->device->maxcollection == parser->device->collection_size) {
            collection = kmalloc(sizeof(struct hid_collection) *
                        parser->device->collection_size * 2, GFP_KERNEL);
            if (collection == NULL) {
                  dbg_hid("failed to reallocate collection array\n");
                  return -1;
            }
            memcpy(collection, parser->device->collection,
                  sizeof(struct hid_collection) *
                  parser->device->collection_size);
            memset(collection + parser->device->collection_size, 0,
                  sizeof(struct hid_collection) *
                  parser->device->collection_size);
            kfree(parser->device->collection);
            parser->device->collection = collection;
            parser->device->collection_size *= 2;
      }

      parser->collection_stack[parser->collection_stack_ptr++] =
            parser->device->maxcollection;

      collection = parser->device->collection +
            parser->device->maxcollection++;
      collection->type = type;
      collection->usage = usage;
      collection->level = parser->collection_stack_ptr - 1;

      if (type == HID_COLLECTION_APPLICATION)
            parser->device->maxapplication++;

      return 0;
}

/*
 * Close a collection.
 */

static int close_collection(struct hid_parser *parser)
{
      if (!parser->collection_stack_ptr) {
            dbg_hid("collection stack underflow\n");
            return -1;
      }
      parser->collection_stack_ptr--;
      return 0;
}

/*
 * Climb up the stack, search for the specified collection type
 * and return the usage.
 */

static unsigned hid_lookup_collection(struct hid_parser *parser, unsigned type)
{
      int n;
      for (n = parser->collection_stack_ptr - 1; n >= 0; n--)
            if (parser->device->collection[parser->collection_stack[n]].type == type)
                  return parser->device->collection[parser->collection_stack[n]].usage;
      return 0; /* we know nothing about this usage type */
}

/*
 * Add a usage to the temporary parser table.
 */

static int hid_add_usage(struct hid_parser *parser, unsigned usage)
{
      if (parser->local.usage_index >= HID_MAX_USAGES) {
            dbg_hid("usage index exceeded\n");
            return -1;
      }
      parser->local.usage[parser->local.usage_index] = usage;
      parser->local.collection_index[parser->local.usage_index] =
            parser->collection_stack_ptr ?
            parser->collection_stack[parser->collection_stack_ptr - 1] : 0;
      parser->local.usage_index++;
      return 0;
}

/*
 * Register a new field for this report.
 */

static int hid_add_field(struct hid_parser *parser, unsigned report_type, unsigned flags)
{
      struct hid_report *report;
      struct hid_field *field;
      int usages;
      unsigned offset;
      int i;

      if (!(report = hid_register_report(parser->device, report_type, parser->global.report_id))) {
            dbg_hid("hid_register_report failed\n");
            return -1;
      }

      if (parser->global.logical_maximum < parser->global.logical_minimum) {
            dbg_hid("logical range invalid %d %d\n", parser->global.logical_minimum, parser->global.logical_maximum);
            return -1;
      }

      offset = report->size;
      report->size += parser->global.report_size * parser->global.report_count;

      if (!parser->local.usage_index) /* Ignore padding fields */
            return 0;

      usages = max_t(int, parser->local.usage_index, parser->global.report_count);

      if ((field = hid_register_field(report, usages, parser->global.report_count)) == NULL)
            return 0;

      field->physical = hid_lookup_collection(parser, HID_COLLECTION_PHYSICAL);
      field->logical = hid_lookup_collection(parser, HID_COLLECTION_LOGICAL);
      field->application = hid_lookup_collection(parser, HID_COLLECTION_APPLICATION);

      for (i = 0; i < usages; i++) {
            int j = i;
            /* Duplicate the last usage we parsed if we have excess values */
            if (i >= parser->local.usage_index)
                  j = parser->local.usage_index - 1;
            field->usage[i].hid = parser->local.usage[j];
            field->usage[i].collection_index =
                  parser->local.collection_index[j];
      }

      field->maxusage = usages;
      field->flags = flags;
      field->report_offset = offset;
      field->report_type = report_type;
      field->report_size = parser->global.report_size;
      field->report_count = parser->global.report_count;
      field->logical_minimum = parser->global.logical_minimum;
      field->logical_maximum = parser->global.logical_maximum;
      field->physical_minimum = parser->global.physical_minimum;
      field->physical_maximum = parser->global.physical_maximum;
      field->unit_exponent = parser->global.unit_exponent;
      field->unit = parser->global.unit;

      return 0;
}

/*
 * Read data value from item.
 */

static u32 item_udata(struct hid_item *item)
{
      switch (item->size) {
            case 1: return item->data.u8;
            case 2: return item->data.u16;
            case 4: return item->data.u32;
      }
      return 0;
}

static s32 item_sdata(struct hid_item *item)
{
      switch (item->size) {
            case 1: return item->data.s8;
            case 2: return item->data.s16;
            case 4: return item->data.s32;
      }
      return 0;
}

/*
 * Process a global item.
 */

static int hid_parser_global(struct hid_parser *parser, struct hid_item *item)
{
      switch (item->tag) {

            case HID_GLOBAL_ITEM_TAG_PUSH:

                  if (parser->global_stack_ptr == HID_GLOBAL_STACK_SIZE) {
                        dbg_hid("global enviroment stack overflow\n");
                        return -1;
                  }

                  memcpy(parser->global_stack + parser->global_stack_ptr++,
                        &parser->global, sizeof(struct hid_global));
                  return 0;

            case HID_GLOBAL_ITEM_TAG_POP:

                  if (!parser->global_stack_ptr) {
                        dbg_hid("global enviroment stack underflow\n");
                        return -1;
                  }

                  memcpy(&parser->global, parser->global_stack + --parser->global_stack_ptr,
                        sizeof(struct hid_global));
                  return 0;

            case HID_GLOBAL_ITEM_TAG_USAGE_PAGE:
                  parser->global.usage_page = item_udata(item);
                  return 0;

            case HID_GLOBAL_ITEM_TAG_LOGICAL_MINIMUM:
                  parser->global.logical_minimum = item_sdata(item);
                  return 0;

            case HID_GLOBAL_ITEM_TAG_LOGICAL_MAXIMUM:
                  if (parser->global.logical_minimum < 0)
                        parser->global.logical_maximum = item_sdata(item);
                  else
                        parser->global.logical_maximum = item_udata(item);
                  return 0;

            case HID_GLOBAL_ITEM_TAG_PHYSICAL_MINIMUM:
                  parser->global.physical_minimum = item_sdata(item);
                  return 0;

            case HID_GLOBAL_ITEM_TAG_PHYSICAL_MAXIMUM:
                  if (parser->global.physical_minimum < 0)
                        parser->global.physical_maximum = item_sdata(item);
                  else
                        parser->global.physical_maximum = item_udata(item);
                  return 0;

            case HID_GLOBAL_ITEM_TAG_UNIT_EXPONENT:
                  parser->global.unit_exponent = item_sdata(item);
                  return 0;

            case HID_GLOBAL_ITEM_TAG_UNIT:
                  parser->global.unit = item_udata(item);
                  return 0;

            case HID_GLOBAL_ITEM_TAG_REPORT_SIZE:
                  if ((parser->global.report_size = item_udata(item)) > 32) {
                        dbg_hid("invalid report_size %d\n", parser->global.report_size);
                        return -1;
                  }
                  return 0;

            case HID_GLOBAL_ITEM_TAG_REPORT_COUNT:
                  if ((parser->global.report_count = item_udata(item)) > HID_MAX_USAGES) {
                        dbg_hid("invalid report_count %d\n", parser->global.report_count);
                        return -1;
                  }
                  return 0;

            case HID_GLOBAL_ITEM_TAG_REPORT_ID:
                  if ((parser->global.report_id = item_udata(item)) == 0) {
                        dbg_hid("report_id 0 is invalid\n");
                        return -1;
                  }
                  return 0;

            default:
                  dbg_hid("unknown global tag 0x%x\n", item->tag);
                  return -1;
      }
}

/*
 * Process a local item.
 */

static int hid_parser_local(struct hid_parser *parser, struct hid_item *item)
{
      __u32 data;
      unsigned n;

      if (item->size == 0) {
            dbg_hid("item data expected for local item\n");
            return -1;
      }

      data = item_udata(item);

      switch (item->tag) {

            case HID_LOCAL_ITEM_TAG_DELIMITER:

                  if (data) {
                        /*
                         * We treat items before the first delimiter
                         * as global to all usage sets (branch 0).
                         * In the moment we process only these global
                         * items and the first delimiter set.
                         */
                        if (parser->local.delimiter_depth != 0) {
                              dbg_hid("nested delimiters\n");
                              return -1;
                        }
                        parser->local.delimiter_depth++;
                        parser->local.delimiter_branch++;
                  } else {
                        if (parser->local.delimiter_depth < 1) {
                              dbg_hid("bogus close delimiter\n");
                              return -1;
                        }
                        parser->local.delimiter_depth--;
                  }
                  return 1;

            case HID_LOCAL_ITEM_TAG_USAGE:

                  if (parser->local.delimiter_branch > 1) {
                        dbg_hid("alternative usage ignored\n");
                        return 0;
                  }

                  if (item->size <= 2)
                        data = (parser->global.usage_page << 16) + data;

                  return hid_add_usage(parser, data);

            case HID_LOCAL_ITEM_TAG_USAGE_MINIMUM:

                  if (parser->local.delimiter_branch > 1) {
                        dbg_hid("alternative usage ignored\n");
                        return 0;
                  }

                  if (item->size <= 2)
                        data = (parser->global.usage_page << 16) + data;

                  parser->local.usage_minimum = data;
                  return 0;

            case HID_LOCAL_ITEM_TAG_USAGE_MAXIMUM:

                  if (parser->local.delimiter_branch > 1) {
                        dbg_hid("alternative usage ignored\n");
                        return 0;
                  }

                  if (item->size <= 2)
                        data = (parser->global.usage_page << 16) + data;

                  for (n = parser->local.usage_minimum; n <= data; n++)
                        if (hid_add_usage(parser, n)) {
                              dbg_hid("hid_add_usage failed\n");
                              return -1;
                        }
                  return 0;

            default:

                  dbg_hid("unknown local item tag 0x%x\n", item->tag);
                  return 0;
      }
      return 0;
}

/*
 * Process a main item.
 */

static int hid_parser_main(struct hid_parser *parser, struct hid_item *item)
{
      __u32 data;
      int ret;

      data = item_udata(item);

      switch (item->tag) {
            case HID_MAIN_ITEM_TAG_BEGIN_COLLECTION:
                  ret = open_collection(parser, data & 0xff);
                  break;
            case HID_MAIN_ITEM_TAG_END_COLLECTION:
                  ret = close_collection(parser);
                  break;
            case HID_MAIN_ITEM_TAG_INPUT:
                  ret = hid_add_field(parser, HID_INPUT_REPORT, data);
                  break;
            case HID_MAIN_ITEM_TAG_OUTPUT:
                  ret = hid_add_field(parser, HID_OUTPUT_REPORT, data);
                  break;
            case HID_MAIN_ITEM_TAG_FEATURE:
                  ret = hid_add_field(parser, HID_FEATURE_REPORT, data);
                  break;
            default:
                  dbg_hid("unknown main item tag 0x%x\n", item->tag);
                  ret = 0;
      }

      memset(&parser->local, 0, sizeof(parser->local));     /* Reset the local parser environment */

      return ret;
}

/*
 * Process a reserved item.
 */

static int hid_parser_reserved(struct hid_parser *parser, struct hid_item *item)
{
      dbg_hid("reserved item type, tag 0x%x\n", item->tag);
      return 0;
}

/*
 * Free a report and all registered fields. The field->usage and
 * field->value table's are allocated behind the field, so we need
 * only to free(field) itself.
 */

static void hid_free_report(struct hid_report *report)
{
      unsigned n;

      for (n = 0; n < report->maxfield; n++)
            kfree(report->field[n]);
      kfree(report);
}

/*
 * Free a device structure, all reports, and all fields.
 */

void hid_free_device(struct hid_device *device)
{
      unsigned i,j;

      for (i = 0; i < HID_REPORT_TYPES; i++) {
            struct hid_report_enum *report_enum = device->report_enum + i;

            for (j = 0; j < 256; j++) {
                  struct hid_report *report = report_enum->report_id_hash[j];
                  if (report)
                        hid_free_report(report);
            }
      }

      kfree(device->rdesc);
      kfree(device->collection);
      kfree(device);
}
EXPORT_SYMBOL_GPL(hid_free_device);

/*
 * Fetch a report description item from the data stream. We support long
 * items, though they are not used yet.
 */

static u8 *fetch_item(__u8 *start, __u8 *end, struct hid_item *item)
{
      u8 b;

      if ((end - start) <= 0)
            return NULL;

      b = *start++;

      item->type = (b >> 2) & 3;
      item->tag  = (b >> 4) & 15;

      if (item->tag == HID_ITEM_TAG_LONG) {

            item->format = HID_ITEM_FORMAT_LONG;

            if ((end - start) < 2)
                  return NULL;

            item->size = *start++;
            item->tag  = *start++;

            if ((end - start) < item->size)
                  return NULL;

            item->data.longdata = start;
            start += item->size;
            return start;
      }

      item->format = HID_ITEM_FORMAT_SHORT;
      item->size = b & 3;

      switch (item->size) {

            case 0:
                  return start;

            case 1:
                  if ((end - start) < 1)
                        return NULL;
                  item->data.u8 = *start++;
                  return start;

            case 2:
                  if ((end - start) < 2)
                        return NULL;
                  item->data.u16 = le16_to_cpu(get_unaligned((__le16*)start));
                  start = (__u8 *)((__le16 *)start + 1);
                  return start;

            case 3:
                  item->size++;
                  if ((end - start) < 4)
                        return NULL;
                  item->data.u32 = le32_to_cpu(get_unaligned((__le32*)start));
                  start = (__u8 *)((__le32 *)start + 1);
                  return start;
      }

      return NULL;
}

/*
 * Parse a report description into a hid_device structure. Reports are
 * enumerated, fields are attached to these reports.
 */

struct hid_device *hid_parse_report(__u8 *start, unsigned size)
{
      struct hid_device *device;
      struct hid_parser *parser;
      struct hid_item item;
      __u8 *end;
      unsigned i;
      static int (*dispatch_type[])(struct hid_parser *parser,
                              struct hid_item *item) = {
            hid_parser_main,
            hid_parser_global,
            hid_parser_local,
            hid_parser_reserved
      };

      if (!(device = kzalloc(sizeof(struct hid_device), GFP_KERNEL)))
            return NULL;

      if (!(device->collection = kzalloc(sizeof(struct hid_collection) *
                           HID_DEFAULT_NUM_COLLECTIONS, GFP_KERNEL))) {
            kfree(device);
            return NULL;
      }
      device->collection_size = HID_DEFAULT_NUM_COLLECTIONS;

      for (i = 0; i < HID_REPORT_TYPES; i++)
            INIT_LIST_HEAD(&device->report_enum[i].report_list);

      if (!(device->rdesc = kmalloc(size, GFP_KERNEL))) {
            kfree(device->collection);
            kfree(device);
            return NULL;
      }
      memcpy(device->rdesc, start, size);
      device->rsize = size;

      if (!(parser = vmalloc(sizeof(struct hid_parser)))) {
            kfree(device->rdesc);
            kfree(device->collection);
            kfree(device);
            return NULL;
      }
      memset(parser, 0, sizeof(struct hid_parser));
      parser->device = device;

      end = start + size;
      while ((start = fetch_item(start, end, &item)) != NULL) {

            if (item.format != HID_ITEM_FORMAT_SHORT) {
                  dbg_hid("unexpected long global item\n");
                  hid_free_device(device);
                  vfree(parser);
                  return NULL;
            }

            if (dispatch_type[item.type](parser, &item)) {
                  dbg_hid("item %u %u %u %u parsing failed\n",
                        item.format, (unsigned)item.size, (unsigned)item.type, (unsigned)item.tag);
                  hid_free_device(device);
                  vfree(parser);
                  return NULL;
            }

            if (start == end) {
                  if (parser->collection_stack_ptr) {
                        dbg_hid("unbalanced collection at end of report description\n");
                        hid_free_device(device);
                        vfree(parser);
                        return NULL;
                  }
                  if (parser->local.delimiter_depth) {
                        dbg_hid("unbalanced delimiter at end of report description\n");
                        hid_free_device(device);
                        vfree(parser);
                        return NULL;
                  }
                  vfree(parser);
                  return device;
            }
      }

      dbg_hid("item fetching failed at offset %d\n", (int)(end - start));
      hid_free_device(device);
      vfree(parser);
      return NULL;
}
EXPORT_SYMBOL_GPL(hid_parse_report);

/*
 * Convert a signed n-bit integer to signed 32-bit integer. Common
 * cases are done through the compiler, the screwed things has to be
 * done by hand.
 */

static s32 snto32(__u32 value, unsigned n)
{
      switch (n) {
            case 8:  return ((__s8)value);
            case 16: return ((__s16)value);
            case 32: return ((__s32)value);
      }
      return value & (1 << (n - 1)) ? value | (-1 << n) : value;
}

/*
 * Convert a signed 32-bit integer to a signed n-bit integer.
 */

static u32 s32ton(__s32 value, unsigned n)
{
      s32 a = value >> (n - 1);
      if (a && a != -1)
            return value < 0 ? 1 << (n - 1) : (1 << (n - 1)) - 1;
      return value & ((1 << n) - 1);
}

/*
 * Extract/implement a data field from/to a little endian report (bit array).
 *
 * Code sort-of follows HID spec:
 *     http://www.usb.org/developers/devclass_docs/HID1_11.pdf
 *
 * While the USB HID spec allows unlimited length bit fields in "report
 * descriptors", most devices never use more than 16 bits.
 * One model of UPS is claimed to report "LINEV" as a 32-bit field.
 * Search linux-kernel and linux-usb-devel archives for "hid-core extract".
 */

static __inline__ __u32 extract(__u8 *report, unsigned offset, unsigned n)
{
      u64 x;

      WARN_ON(n > 32);

      report += offset >> 3;  /* adjust byte index */
      offset &= 7;            /* now only need bit offset into one byte */
      x = le64_to_cpu(get_unaligned((__le64 *) report));
      x = (x >> offset) & ((1ULL << n) - 1);  /* extract bit field */
      return (u32) x;
}

/*
 * "implement" : set bits in a little endian bit stream.
 * Same concepts as "extract" (see comments above).
 * The data mangled in the bit stream remains in little endian
 * order the whole time. It make more sense to talk about
 * endianness of register values by considering a register
 * a "cached" copy of the little endiad bit stream.
 */
static __inline__ void implement(__u8 *report, unsigned offset, unsigned n, __u32 value)
{
      __le64 x;
      u64 m = (1ULL << n) - 1;

      WARN_ON(n > 32);

      WARN_ON(value > m);
      value &= m;

      report += offset >> 3;
      offset &= 7;

      x = get_unaligned((__le64 *)report);
      x &= cpu_to_le64(~(m << offset));
      x |= cpu_to_le64(((u64) value) << offset);
      put_unaligned(x, (__le64 *) report);
}

/*
 * Search an array for a value.
 */

static __inline__ int search(__s32 *array, __s32 value, unsigned n)
{
      while (n--) {
            if (*array++ == value)
                  return 0;
      }
      return -1;
}

static void hid_process_event(struct hid_device *hid, struct hid_field *field, struct hid_usage *usage, __s32 value, int interrupt)
{
      hid_dump_input(usage, value);
      if (hid->claimed & HID_CLAIMED_INPUT)
            hidinput_hid_event(hid, field, usage, value);
      if (hid->claimed & HID_CLAIMED_HIDDEV && interrupt && hid->hiddev_hid_event)
            hid->hiddev_hid_event(hid, field, usage, value);
}

/*
 * Analyse a received field, and fetch the data from it. The field
 * content is stored for next report processing (we do differential
 * reporting to the layer).
 */

void hid_input_field(struct hid_device *hid, struct hid_field *field, __u8 *data, int interrupt)
{
      unsigned n;
      unsigned count = field->report_count;
      unsigned offset = field->report_offset;
      unsigned size = field->report_size;
      __s32 min = field->logical_minimum;
      __s32 max = field->logical_maximum;
      __s32 *value;

      if (!(value = kmalloc(sizeof(__s32) * count, GFP_ATOMIC)))
            return;

      for (n = 0; n < count; n++) {

                  value[n] = min < 0 ? snto32(extract(data, offset + n * size, size), size) :
                                        extract(data, offset + n * size, size);

                  if (!(field->flags & HID_MAIN_ITEM_VARIABLE) /* Ignore report if ErrorRollOver */
                      && value[n] >= min && value[n] <= max
                      && field->usage[value[n] - min].hid == HID_UP_KEYBOARD + 1)
                        goto exit;
      }

      for (n = 0; n < count; n++) {

            if (HID_MAIN_ITEM_VARIABLE & field->flags) {
                  hid_process_event(hid, field, &field->usage[n], value[n], interrupt);
                  continue;
            }

            if (field->value[n] >= min && field->value[n] <= max
                  && field->usage[field->value[n] - min].hid
                  && search(value, field->value[n], count))
                        hid_process_event(hid, field, &field->usage[field->value[n] - min], 0, interrupt);

            if (value[n] >= min && value[n] <= max
                  && field->usage[value[n] - min].hid
                  && search(field->value, value[n], count))
                        hid_process_event(hid, field, &field->usage[value[n] - min], 1, interrupt);
      }

      memcpy(field->value, value, count * sizeof(__s32));
exit:
      kfree(value);
}
EXPORT_SYMBOL_GPL(hid_input_field);

/*
 * Output the field into the report.
 */

static void hid_output_field(struct hid_field *field, __u8 *data)
{
      unsigned count = field->report_count;
      unsigned offset = field->report_offset;
      unsigned size = field->report_size;
      unsigned bitsused = offset + count * size;
      unsigned n;

      /* make sure the unused bits in the last byte are zeros */
      if (count > 0 && size > 0 && (bitsused % 8) != 0)
            data[(bitsused-1)/8] &= (1 << (bitsused % 8)) - 1;

      for (n = 0; n < count; n++) {
            if (field->logical_minimum < 0)     /* signed values */
                  implement(data, offset + n * size, size, s32ton(field->value[n], size));
            else                    /* unsigned values */
                  implement(data, offset + n * size, size, field->value[n]);
      }
}

/*
 * Create a report.
 */

void hid_output_report(struct hid_report *report, __u8 *data)
{
      unsigned n;

      if (report->id > 0)
            *data++ = report->id;

      for (n = 0; n < report->maxfield; n++)
            hid_output_field(report->field[n], data);
}
EXPORT_SYMBOL_GPL(hid_output_report);

/*
 * Set a field value. The report this field belongs to has to be
 * created and transferred to the device, to set this value in the
 * device.
 */

int hid_set_field(struct hid_field *field, unsigned offset, __s32 value)
{
      unsigned size = field->report_size;

      hid_dump_input(field->usage + offset, value);

      if (offset >= field->report_count) {
            dbg_hid("offset (%d) exceeds report_count (%d)\n", offset, field->report_count);
            hid_dump_field(field, 8);
            return -1;
      }
      if (field->logical_minimum < 0) {
            if (value != snto32(s32ton(value, size), size)) {
                  dbg_hid("value %d is out of range\n", value);
                  return -1;
            }
      }
      field->value[offset] = value;
      return 0;
}
EXPORT_SYMBOL_GPL(hid_set_field);

int hid_input_report(struct hid_device *hid, int type, u8 *data, int size, int interrupt)
{
      struct hid_report_enum *report_enum = hid->report_enum + type;
      struct hid_report *report;
      int n, rsize, i;

      if (!hid)
            return -ENODEV;

      if (!size) {
            dbg_hid("empty report\n");
            return -1;
      }

      dbg_hid("report (size %u) (%snumbered)\n", size, report_enum->numbered ? "" : "un");

      n = 0;                          /* Normally report number is 0 */
      if (report_enum->numbered) {    /* Device uses numbered reports, data[0] is report number */
            n = *data++;
            size--;
      }

      /* dump the report descriptor */
      dbg_hid("report %d (size %u) = ", n, size);
      for (i = 0; i < size; i++)
            dbg_hid_line(" %02x", data[i]);
      dbg_hid_line("\n");

      if (!(report = report_enum->report_id_hash[n])) {
            dbg_hid("undefined report_id %d received\n", n);
            return -1;
      }

      rsize = ((report->size - 1) >> 3) + 1;

      if (size < rsize) {
            dbg_hid("report %d is too short, (%d < %d)\n", report->id, size, rsize);
            memset(data + size, 0, rsize - size);
      }

      if ((hid->claimed & HID_CLAIMED_HIDDEV) && hid->hiddev_report_event)
            hid->hiddev_report_event(hid, report);
      if (hid->claimed & HID_CLAIMED_HIDRAW)
            hidraw_report_event(hid, data, size);

      for (n = 0; n < report->maxfield; n++)
            hid_input_field(hid, report->field[n], data, interrupt);

      if (hid->claimed & HID_CLAIMED_INPUT)
            hidinput_report_event(hid, report);

      return 0;
}
EXPORT_SYMBOL_GPL(hid_input_report);

static int __init hid_init(void)
{
      return hidraw_init();
}

static void __exit hid_exit(void)
{
      hidraw_exit();
}

module_init(hid_init);
module_exit(hid_exit);

MODULE_LICENSE(DRIVER_LICENSE);


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