drivers/base/firmware_class.c

   1 /*
   2  * firmware_class.c - Multi purpose firmware loading support
   3  *
   4  * Copyright (c) 2003 Manuel Estrada Sainz
   5  *
   6  * Please see Documentation/firmware_class/ for more information.
   7  *
   8  */
   9
  10 #include <linux/capability.h>
  11 #include <linux/device.h>
  12 #include <linux/module.h>
  13 #include <linux/init.h>
  14 #include <linux/timer.h>
  15 #include <linux/vmalloc.h>
  16 #include <linux/interrupt.h>
  17 #include <linux/bitops.h>
  18 #include <linux/mutex.h>
  19 #include <linux/workqueue.h>
  20 #include <linux/highmem.h>
  21 #include <linux/firmware.h>
  22 #include <linux/slab.h>
  23 #include <linux/sched.h>
  24
  25 MODULE_AUTHOR("Manuel Estrada Sainz");
  26 MODULE_DESCRIPTION("Multi purpose firmware loading support");
  27 MODULE_LICENSE("GPL");
  28
  29 /* Builtin firmware support */
  30
  31 #ifdef CONFIG_FW_LOADER
  32
  33 extern struct builtin_fw __start_builtin_fw[];
  34 extern struct builtin_fw __end_builtin_fw[];
  35
  36 static bool fw_get_builtin_firmware(struct firmware *fw, const char *name)
  37 {
  38         struct builtin_fw *b_fw;
  39
  40         for (b_fw = __start_builtin_fw; b_fw != __end_builtin_fw; b_fw++) {
  41                 if (strcmp(name, b_fw->name) == 0) {
  42                         fw->size = b_fw->size;
  43                         fw->data = b_fw->data;
  44                         return true;
  45                 }
  46         }
  47
  48         return false;
  49 }
  50
  51 static bool fw_is_builtin_firmware(const struct firmware *fw)
  52 {
  53         struct builtin_fw *b_fw;
  54
  55         for (b_fw = __start_builtin_fw; b_fw != __end_builtin_fw; b_fw++)
  56                 if (fw->data == b_fw->data)
  57                         return true;
  58
  59         return false;
  60 }
  61
  62 #else /* Module case - no builtin firmware support */
  63
  64 static inline bool fw_get_builtin_firmware(struct firmware *fw, const char *name)
  65 {
  66         return false;
  67 }
  68
  69 static inline bool fw_is_builtin_firmware(const struct firmware *fw)
  70 {
  71         return false;
  72 }
  73 #endif
  74
  75 enum {
  76         FW_STATUS_LOADING,
  77         FW_STATUS_DONE,
  78         FW_STATUS_ABORT,
  79 };
  80
  81 static int loading_timeout = 60;        /* In seconds */
  82
  83 static inline long firmware_loading_timeout(void)
  84 {
  85         return loading_timeout > 0 ? loading_timeout * HZ : MAX_SCHEDULE_TIMEOUT;
  86 }
  87
  88 /* fw_lock could be moved to 'struct firmware_priv' but since it is just
  89  * guarding for corner cases a global lock should be OK */
  90 static DEFINE_MUTEX(fw_lock);
  91
  92 struct firmware_priv {
  93         struct completion completion;
  94         struct firmware *fw;
  95         unsigned long status;
  96         struct page **pages;
  97         int nr_pages;
  98         int page_array_size;
  99         struct timer_list timeout;
 100         struct device dev;
 101         bool nowait;
 102         char fw_id[];
 103 };
 104
 105 static struct firmware_priv *to_firmware_priv(struct device *dev)
 106 {
 107         return container_of(dev, struct firmware_priv, dev);
 108 }
 109
 110 static void fw_load_abort(struct firmware_priv *fw_priv)
 111 {
 112         set_bit(FW_STATUS_ABORT, &fw_priv->status);
 113         wmb();
 114         complete(&fw_priv->completion);
 115 }
 116
 117 static ssize_t firmware_timeout_show(struct class *class,
 118                                      struct class_attribute *attr,
 119                                      char *buf)
 120 {
 121         return sprintf(buf, "%d\n", loading_timeout);
 122 }
 123
 124 /**
 125  * firmware_timeout_store - set number of seconds to wait for firmware
 126  * @class: device class pointer
 127  * @attr: device attribute pointer
 128  * @buf: buffer to scan for timeout value
 129  * @count: number of bytes in @buf
 130  *
 131  *      Sets the number of seconds to wait for the firmware.  Once
 132  *      this expires an error will be returned to the driver and no
 133  *      firmware will be provided.
 134  *
 135  *      Note: zero means 'wait forever'.
 136  **/
 137 static ssize_t firmware_timeout_store(struct class *class,
 138                                       struct class_attribute *attr,
 139                                       const char *buf, size_t count)
 140 {
 141         loading_timeout = simple_strtol(buf, NULL, 10);
 142         if (loading_timeout < 0)
 143                 loading_timeout = 0;
 144
 145         return count;
 146 }
 147
 148 static struct class_attribute firmware_class_attrs[] = {
 149         __ATTR(timeout, S_IWUSR | S_IRUGO,
 150                 firmware_timeout_show, firmware_timeout_store),
 151         __ATTR_NULL
 152 };
 153
 154 static void fw_dev_release(struct device *dev)
 155 {
 156         struct firmware_priv *fw_priv = to_firmware_priv(dev);
 157         int i;
 158
 159         for (i = 0; i < fw_priv->nr_pages; i++)
 160                 __free_page(fw_priv->pages[i]);
 161         kfree(fw_priv->pages);
 162         kfree(fw_priv);
 163
 164         module_put(THIS_MODULE);
 165 }
 166
 167 static int firmware_uevent(struct device *dev, struct kobj_uevent_env *env)
 168 {
 169         struct firmware_priv *fw_priv = to_firmware_priv(dev);
 170
 171         if (add_uevent_var(env, "FIRMWARE=%s", fw_priv->fw_id))
 172                 return -ENOMEM;
 173         if (add_uevent_var(env, "TIMEOUT=%i", loading_timeout))
 174                 return -ENOMEM;
 175         if (add_uevent_var(env, "ASYNC=%d", fw_priv->nowait))
 176                 return -ENOMEM;
 177
 178         return 0;
 179 }
 180
 181 static struct class firmware_class = {
 182         .name           = "firmware",
 183         .class_attrs    = firmware_class_attrs,
 184         .dev_uevent     = firmware_uevent,
 185         .dev_release    = fw_dev_release,
 186 };
 187
 188 static ssize_t firmware_loading_show(struct device *dev,
 189                                      struct device_attribute *attr, char *buf)
 190 {
 191         struct firmware_priv *fw_priv = to_firmware_priv(dev);
 192         int loading = test_bit(FW_STATUS_LOADING, &fw_priv->status);
 193
 194         return sprintf(buf, "%d\n", loading);
 195 }
 196
 197 static void firmware_free_data(const struct firmware *fw)
 198 {
 199         int i;
 200         vunmap(fw->data);
 201         if (fw->pages) {
 202                 for (i = 0; i < PFN_UP(fw->size); i++)
 203                         __free_page(fw->pages[i]);
 204                 kfree(fw->pages);
 205         }
 206 }
 207
 208 /* Some architectures don't have PAGE_KERNEL_RO */
 209 #ifndef PAGE_KERNEL_RO
 210 #define PAGE_KERNEL_RO PAGE_KERNEL
 211 #endif
 212 /**
 213  * firmware_loading_store - set value in the 'loading' control file
 214  * @dev: device pointer
 215  * @attr: device attribute pointer
 216  * @buf: buffer to scan for loading control value
 217  * @count: number of bytes in @buf
 218  *
 219  *      The relevant values are:
 220  *
 221  *       1: Start a load, discarding any previous partial load.
 222  *       0: Conclude the load and hand the data to the driver code.
 223  *      -1: Conclude the load with an error and discard any written data.
 224  **/
 225 static ssize_t firmware_loading_store(struct device *dev,
 226                                       struct device_attribute *attr,
 227                                       const char *buf, size_t count)
 228 {
 229         struct firmware_priv *fw_priv = to_firmware_priv(dev);
 230         int loading = simple_strtol(buf, NULL, 10);
 231         int i;
 232
 233         mutex_lock(&fw_lock);
 234
 235         if (!fw_priv->fw)
 236                 goto out;
 237
 238         switch (loading) {
 239         case 1:
 240                 firmware_free_data(fw_priv->fw);
 241                 memset(fw_priv->fw, 0, sizeof(struct firmware));
 242                 /* If the pages are not owned by 'struct firmware' */
 243                 for (i = 0; i < fw_priv->nr_pages; i++)
 244                         __free_page(fw_priv->pages[i]);
 245                 kfree(fw_priv->pages);
 246                 fw_priv->pages = NULL;
 247                 fw_priv->page_array_size = 0;
 248                 fw_priv->nr_pages = 0;
 249                 set_bit(FW_STATUS_LOADING, &fw_priv->status);
 250                 break;
 251         case 0:
 252                 if (test_bit(FW_STATUS_LOADING, &fw_priv->status)) {
 253                         vunmap(fw_priv->fw->data);
 254                         fw_priv->fw->data = vmap(fw_priv->pages,
 255                                                  fw_priv->nr_pages,
 256                                                  0, PAGE_KERNEL_RO);
 257                         if (!fw_priv->fw->data) {
 258                                 dev_err(dev, "%s: vmap() failed\n", __func__);
 259                                 goto err;
 260                         }
 261                         /* Pages are now owned by 'struct firmware' */
 262                         fw_priv->fw->pages = fw_priv->pages;
 263                         fw_priv->pages = NULL;
 264
 265                         fw_priv->page_array_size = 0;
 266                         fw_priv->nr_pages = 0;
 267                         complete(&fw_priv->completion);
 268                         clear_bit(FW_STATUS_LOADING, &fw_priv->status);
 269                         break;
 270                 }
 271                 /* fallthrough */
 272         default:
 273                 dev_err(dev, "%s: unexpected value (%d)\n", __func__, loading);
 274                 /* fallthrough */
 275         case -1:
 276         err:
 277                 fw_load_abort(fw_priv);
 278                 break;
 279         }
 280 out:
 281         mutex_unlock(&fw_lock);
 282         return count;
 283 }
 284
 285 static DEVICE_ATTR(loading, 0644, firmware_loading_show, firmware_loading_store);
 286
 287 static ssize_t firmware_data_read(struct file *filp, struct kobject *kobj,
 288                                   struct bin_attribute *bin_attr,
 289                                   char *buffer, loff_t offset, size_t count)
 290 {
 291         struct device *dev = kobj_to_dev(kobj);
 292         struct firmware_priv *fw_priv = to_firmware_priv(dev);
 293         struct firmware *fw;
 294         ssize_t ret_count;
 295
 296         mutex_lock(&fw_lock);
 297         fw = fw_priv->fw;
 298         if (!fw || test_bit(FW_STATUS_DONE, &fw_priv->status)) {
 299                 ret_count = -ENODEV;
 300                 goto out;
 301         }
 302         if (offset > fw->size) {
 303                 ret_count = 0;
 304                 goto out;
 305         }
 306         if (count > fw->size - offset)
 307                 count = fw->size - offset;
 308
 309         ret_count = count;
 310
 311         while (count) {
 312                 void *page_data;
 313                 int page_nr = offset >> PAGE_SHIFT;
 314                 int page_ofs = offset & (PAGE_SIZE-1);
 315                 int page_cnt = min_t(size_t, PAGE_SIZE - page_ofs, count);
 316
 317                 page_data = kmap(fw_priv->pages[page_nr]);
 318
 319                 memcpy(buffer, page_data + page_ofs, page_cnt);
 320
 321                 kunmap(fw_priv->pages[page_nr]);
 322                 buffer += page_cnt;
 323                 offset += page_cnt;
 324                 count -= page_cnt;
 325         }
 326 out:
 327         mutex_unlock(&fw_lock);
 328         return ret_count;
 329 }
 330
 331 static int fw_realloc_buffer(struct firmware_priv *fw_priv, int min_size)
 332 {
 333         int pages_needed = ALIGN(min_size, PAGE_SIZE) >> PAGE_SHIFT;
 334
 335         /* If the array of pages is too small, grow it... */
 336         if (fw_priv->page_array_size < pages_needed) {
 337                 int new_array_size = max(pages_needed,
 338                                          fw_priv->page_array_size * 2);
 339                 struct page **new_pages;
 340
 341                 new_pages = kmalloc(new_array_size * sizeof(void *),
 342                                     GFP_KERNEL);
 343                 if (!new_pages) {
 344                         fw_load_abort(fw_priv);
 345                         return -ENOMEM;
 346                 }
 347                 memcpy(new_pages, fw_priv->pages,
 348                        fw_priv->page_array_size * sizeof(void *));
 349                 memset(&new_pages[fw_priv->page_array_size], 0, sizeof(void *) *
 350                        (new_array_size - fw_priv->page_array_size));
 351                 kfree(fw_priv->pages);
 352                 fw_priv->pages = new_pages;
 353                 fw_priv->page_array_size = new_array_size;
 354         }
 355
 356         while (fw_priv->nr_pages < pages_needed) {
 357                 fw_priv->pages[fw_priv->nr_pages] =
 358                         alloc_page(GFP_KERNEL | __GFP_HIGHMEM);
 359
 360                 if (!fw_priv->pages[fw_priv->nr_pages]) {
 361                         fw_load_abort(fw_priv);
 362                         return -ENOMEM;
 363                 }
 364                 fw_priv->nr_pages++;
 365         }
 366         return 0;
 367 }
 368
 369 /**
 370  * firmware_data_write - write method for firmware
 371  * @filp: open sysfs file
 372  * @kobj: kobject for the device
 373  * @bin_attr: bin_attr structure
 374  * @buffer: buffer being written
 375  * @offset: buffer offset for write in total data store area
 376  * @count: buffer size
 377  *
 378  *      Data written to the 'data' attribute will be later handed to
 379  *      the driver as a firmware image.
 380  **/
 381 static ssize_t firmware_data_write(struct file *filp, struct kobject *kobj,
 382                                    struct bin_attribute *bin_attr,
 383                                    char *buffer, loff_t offset, size_t count)
 384 {
 385         struct device *dev = kobj_to_dev(kobj);
 386         struct firmware_priv *fw_priv = to_firmware_priv(dev);
 387         struct firmware *fw;
 388         ssize_t retval;
 389
 390         if (!capable(CAP_SYS_RAWIO))
 391                 return -EPERM;
 392
 393         mutex_lock(&fw_lock);
 394         fw = fw_priv->fw;
 395         if (!fw || test_bit(FW_STATUS_DONE, &fw_priv->status)) {
 396                 retval = -ENODEV;
 397                 goto out;
 398         }
 399         retval = fw_realloc_buffer(fw_priv, offset + count);
 400         if (retval)
 401                 goto out;
 402
 403         retval = count;
 404
 405         while (count) {
 406                 void *page_data;
 407                 int page_nr = offset >> PAGE_SHIFT;
 408                 int page_ofs = offset & (PAGE_SIZE - 1);
 409                 int page_cnt = min_t(size_t, PAGE_SIZE - page_ofs, count);
 410
 411                 page_data = kmap(fw_priv->pages[page_nr]);
 412
 413                 memcpy(page_data + page_ofs, buffer, page_cnt);
 414
 415                 kunmap(fw_priv->pages[page_nr]);
 416                 buffer += page_cnt;
 417                 offset += page_cnt;
 418                 count -= page_cnt;
 419         }
 420
 421         fw->size = max_t(size_t, offset, fw->size);
 422 out:
 423         mutex_unlock(&fw_lock);
 424         return retval;
 425 }
 426
 427 static struct bin_attribute firmware_attr_data = {
 428         .attr = { .name = "data", .mode = 0644 },
 429         .size = 0,
 430         .read = firmware_data_read,
 431         .write = firmware_data_write,
 432 };
 433
 434 static void firmware_class_timeout(u_long data)
 435 {
 436         struct firmware_priv *fw_priv = (struct firmware_priv *) data;
 437
 438         fw_load_abort(fw_priv);
 439 }
 440
 441 static struct firmware_priv *
 442 fw_create_instance(struct firmware *firmware, const char *fw_name,
 443                    struct device *device, bool uevent, bool nowait)
 444 {
 445         struct firmware_priv *fw_priv;
 446         struct device *f_dev;
 447
 448         fw_priv = kzalloc(sizeof(*fw_priv) + strlen(fw_name) + 1 , GFP_KERNEL);
 449         if (!fw_priv) {
 450                 dev_err(device, "%s: kmalloc failed\n", __func__);
 451                 return ERR_PTR(-ENOMEM);
 452         }
 453
 454         fw_priv->fw = firmware;
 455         fw_priv->nowait = nowait;
 456         strcpy(fw_priv->fw_id, fw_name);
 457         init_completion(&fw_priv->completion);
 458         setup_timer(&fw_priv->timeout,
 459                     firmware_class_timeout, (u_long) fw_priv);
 460
 461         f_dev = &fw_priv->dev;
 462
 463         device_initialize(f_dev);
 464         dev_set_name(f_dev, "%s", dev_name(device));
 465         f_dev->parent = device;
 466         f_dev->class = &firmware_class;
 467
 468         return fw_priv;
 469 }
 470
 471 static struct firmware_priv *
 472 _request_firmware_prepare(const struct firmware **firmware_p, const char *name,
 473                           struct device *device, bool uevent, bool nowait)
 474 {
 475         struct firmware *firmware;
 476         struct firmware_priv *fw_priv;
 477
 478         if (!firmware_p)
 479                 return ERR_PTR(-EINVAL);
 480
 481         *firmware_p = firmware = kzalloc(sizeof(*firmware), GFP_KERNEL);
 482         if (!firmware) {
 483                 dev_err(device, "%s: kmalloc(struct firmware) failed\n",
 484                         __func__);
 485                 return ERR_PTR(-ENOMEM);
 486         }
 487
 488         if (fw_get_builtin_firmware(firmware, name)) {
 489                 dev_dbg(device, "firmware: using built-in firmware %s\n", name);
 490                 return NULL;
 491         }
 492
 493         fw_priv = fw_create_instance(firmware, name, device, uevent, nowait);
 494         if (IS_ERR(fw_priv)) {
 495                 release_firmware(firmware);
 496                 *firmware_p = NULL;
 497         }
 498         return fw_priv;
 499 }
 500
 501 static void _request_firmware_cleanup(const struct firmware **firmware_p)
 502 {
 503         release_firmware(*firmware_p);
 504         *firmware_p = NULL;
 505 }
 506
 507 static int _request_firmware_load(struct firmware_priv *fw_priv, bool uevent,
 508                                   long timeout)
 509 {
 510         int retval = 0;
 511         struct device *f_dev = &fw_priv->dev;
 512
 513         dev_set_uevent_suppress(f_dev, true);
 514
 515         /* Need to pin this module until class device is destroyed */
 516         __module_get(THIS_MODULE);
 517
 518         retval = device_add(f_dev);
 519         if (retval) {
 520                 dev_err(f_dev, "%s: device_register failed\n", __func__);
 521                 goto err_put_dev;
 522         }
 523
 524         retval = device_create_bin_file(f_dev, &firmware_attr_data);
 525         if (retval) {
 526                 dev_err(f_dev, "%s: sysfs_create_bin_file failed\n", __func__);
 527                 goto err_del_dev;
 528         }
 529
 530         retval = device_create_file(f_dev, &dev_attr_loading);
 531         if (retval) {
 532                 dev_err(f_dev, "%s: device_create_file failed\n", __func__);
 533                 goto err_del_bin_attr;
 534         }
 535
 536         if (uevent) {
 537                 dev_set_uevent_suppress(f_dev, false);
 538                 dev_dbg(f_dev, "firmware: requesting %s\n", fw_priv->fw_id);
 539                 if (timeout != MAX_SCHEDULE_TIMEOUT)
 540                         mod_timer(&fw_priv->timeout,
 541                                   round_jiffies_up(jiffies + timeout));
 542
 543                 kobject_uevent(&fw_priv->dev.kobj, KOBJ_ADD);
 544         }
 545
 546         wait_for_completion(&fw_priv->completion);
 547
 548         set_bit(FW_STATUS_DONE, &fw_priv->status);
 549         del_timer_sync(&fw_priv->timeout);
 550
 551         mutex_lock(&fw_lock);
 552         if (!fw_priv->fw->size || test_bit(FW_STATUS_ABORT, &fw_priv->status))
 553                 retval = -ENOENT;
 554         fw_priv->fw = NULL;
 555         mutex_unlock(&fw_lock);
 556
 557         device_remove_file(f_dev, &dev_attr_loading);
 558 err_del_bin_attr:
 559         device_remove_bin_file(f_dev, &firmware_attr_data);
 560 err_del_dev:
 561         device_del(f_dev);
 562 err_put_dev:
 563         put_device(f_dev);
 564         return retval;
 565 }
 566
 567 /**
 568  * request_firmware: - send firmware request and wait for it
 569  * @firmware_p: pointer to firmware image
 570  * @name: name of firmware file
 571  * @device: device for which firmware is being loaded
 572  *
 573  *      @firmware_p will be used to return a firmware image by the name
 574  *      of @name for device @device.
 575  *
 576  *      Should be called from user context where sleeping is allowed.
 577  *
 578  *      @name will be used as $FIRMWARE in the uevent environment and
 579  *      should be distinctive enough not to be confused with any other
 580  *      firmware image for this or any other device.
 581  **/
 582 int
 583 request_firmware(const struct firmware **firmware_p, const char *name,
 584                  struct device *device)
 585 {
 586         struct firmware_priv *fw_priv;
 587         int ret;
 588
 589         fw_priv = _request_firmware_prepare(firmware_p, name, device, true,
 590                                             false);
 591         if (IS_ERR_OR_NULL(fw_priv))
 592                 return PTR_RET(fw_priv);
 593
 594         ret = usermodehelper_read_trylock();
 595         if (WARN_ON(ret)) {
 596                 dev_err(device, "firmware: %s will not be loaded\n", name);
 597         } else {
 598                 ret = _request_firmware_load(fw_priv, true,
 599                                         firmware_loading_timeout());
 600                 usermodehelper_read_unlock();
 601         }
 602         if (ret)
 603                 _request_firmware_cleanup(firmware_p);
 604
 605         return ret;
 606 }
 607
 608 /**
 609  * release_firmware: - release the resource associated with a firmware image
 610  * @fw: firmware resource to release
 611  **/
 612 void release_firmware(const struct firmware *fw)
 613 {
 614         if (fw) {
 615                 if (!fw_is_builtin_firmware(fw))
 616                         firmware_free_data(fw);
 617                 kfree(fw);
 618         }
 619 }
 620
 621 /* Async support */
 622 struct firmware_work {
 623         struct work_struct work;
 624         struct module *module;
 625         const char *name;
 626         struct device *device;
 627         void *context;
 628         void (*cont)(const struct firmware *fw, void *context);
 629         bool uevent;
 630 };
 631
 632 static void request_firmware_work_func(struct work_struct *work)
 633 {
 634         struct firmware_work *fw_work;
 635         const struct firmware *fw;
 636         struct firmware_priv *fw_priv;
 637         long timeout;
 638         int ret;
 639
 640         fw_work = container_of(work, struct firmware_work, work);
 641         fw_priv = _request_firmware_prepare(&fw, fw_work->name, fw_work->device,
 642                         fw_work->uevent, true);
 643         if (IS_ERR_OR_NULL(fw_priv)) {
 644                 ret = PTR_RET(fw_priv);
 645                 goto out;
 646         }
 647
 648         timeout = usermodehelper_read_lock_wait(firmware_loading_timeout());
 649         if (timeout) {
 650                 ret = _request_firmware_load(fw_priv, fw_work->uevent, timeout);
 651                 usermodehelper_read_unlock();
 652         } else {
 653                 dev_dbg(fw_work->device, "firmware: %s loading timed out\n",
 654                         fw_work->name);
 655                 ret = -EAGAIN;
 656         }
 657         if (ret)
 658                 _request_firmware_cleanup(&fw);
 659
 660  out:
 661         fw_work->cont(fw, fw_work->context);
 662
 663         module_put(fw_work->module);
 664         kfree(fw_work);
 665 }
 666
 667 /**
 668  * request_firmware_nowait - asynchronous version of request_firmware
 669  * @module: module requesting the firmware
 670  * @uevent: sends uevent to copy the firmware image if this flag
 671  *      is non-zero else the firmware copy must be done manually.
 672  * @name: name of firmware file
 673  * @device: device for which firmware is being loaded
 674  * @gfp: allocation flags
 675  * @context: will be passed over to @cont, and
 676  *      @fw may be %NULL if firmware request fails.
 677  * @cont: function will be called asynchronously when the firmware
 678  *      request is over.
 679  *
 680  *      Asynchronous variant of request_firmware() for user contexts where
 681  *      it is not possible to sleep for long time. It can't be called
 682  *      in atomic contexts.
 683  **/
 684 int
 685 request_firmware_nowait(
 686         struct module *module, bool uevent,
 687         const char *name, struct device *device, gfp_t gfp, void *context,
 688         void (*cont)(const struct firmware *fw, void *context))
 689 {
 690         struct firmware_work *fw_work;
 691
 692         fw_work = kzalloc(sizeof (struct firmware_work), gfp);
 693         if (!fw_work)
 694                 return -ENOMEM;
 695
 696         fw_work->module = module;
 697         fw_work->name = name;
 698         fw_work->device = device;
 699         fw_work->context = context;
 700         fw_work->cont = cont;
 701         fw_work->uevent = uevent;
 702
 703         if (!try_module_get(module)) {
 704                 kfree(fw_work);
 705                 return -EFAULT;
 706         }
 707
 708         INIT_WORK(&fw_work->work, request_firmware_work_func);
 709         schedule_work(&fw_work->work);
 710         return 0;
 711 }
 712
 713 static int __init firmware_class_init(void)
 714 {
 715         return class_register(&firmware_class);
 716 }
 717
 718 static void __exit firmware_class_exit(void)
 719 {
 720         class_unregister(&firmware_class);
 721 }
 722
 723 fs_initcall(firmware_class_init);
 724 module_exit(firmware_class_exit);
 725
 726 EXPORT_SYMBOL(release_firmware);
 727 EXPORT_SYMBOL(request_firmware);
 728 EXPORT_SYMBOL(request_firmware_nowait);