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