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