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