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