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