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