compat/compat_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 compat_firmware_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 #if 0
  34
  35 extern struct builtin_fw __start_builtin_fw[];
  36 extern struct builtin_fw __end_builtin_fw[];
  37
  38 static bool fw_get_builtin_firmware(struct firmware *fw, const char *name)
  39 {
  40         struct builtin_fw *b_fw;
  41
  42         for (b_fw = __start_builtin_fw; b_fw != __end_builtin_fw; b_fw++) {
  43                 if (strcmp(name, b_fw->name) == 0) {
  44                         fw->size = b_fw->size;
  45                         fw->data = b_fw->data;
  46                         return true;
  47                 }
  48         }
  49
  50         return false;
  51 }
  52
  53 static bool fw_is_builtin_firmware(const struct firmware *fw)
  54 {
  55         struct builtin_fw *b_fw;
  56
  57         for (b_fw = __start_builtin_fw; b_fw != __end_builtin_fw; b_fw++)
  58                 if (fw->data == b_fw->data)
  59                         return true;
  60
  61         return false;
  62 }
  63
  64 #else /* Module case - no builtin firmware support */
  65
  66 static inline bool fw_get_builtin_firmware(struct firmware *fw, const char *name)
  67 {
  68         return false;
  69 }
  70
  71 static inline bool fw_is_builtin_firmware(const struct firmware *fw)
  72 {
  73         return false;
  74 }
  75 #endif
  76
  77 enum {
  78         FW_STATUS_LOADING,
  79         FW_STATUS_DONE,
  80         FW_STATUS_ABORT,
  81 };
  82
  83 static int loading_timeout = 60;        /* In seconds */
  84
  85 /* fw_lock could be moved to 'struct firmware_priv' but since it is just
  86  * guarding for corner cases a global lock should be OK */
  87 static DEFINE_MUTEX(fw_lock);
  88
  89 struct firmware_priv {
  90         struct completion completion;
  91         struct firmware *fw;
  92         unsigned long status;
  93         struct page **pages;
  94         int nr_pages;
  95         int page_array_size;
  96         struct timer_list timeout;
  97         struct device dev;
  98         bool nowait;
  99         char fw_id[];
 100 };
 101
 102 static struct firmware_priv *to_firmware_priv(struct device *dev)
 103 {
 104         return container_of(dev, struct firmware_priv, dev);
 105 }
 106
 107 static void fw_load_abort(struct firmware_priv *fw_priv)
 108 {
 109         set_bit(FW_STATUS_ABORT, &fw_priv->status);
 110         wmb();
 111         complete(&fw_priv->completion);
 112 }
 113
 114 static ssize_t firmware_timeout_show(struct class *class,
 115                                      char *buf)
 116 {
 117         return sprintf(buf, "%d\n", loading_timeout);
 118 }
 119
 120 /**
 121  * firmware_timeout_store - set number of seconds to wait for firmware
 122  * @class: device class pointer
 123  * @buf: buffer to scan for timeout value
 124  * @count: number of bytes in @buf
 125  *
 126  *      Sets the number of seconds to wait for the firmware.  Once
 127  *      this expires an error will be returned to the driver and no
 128  *      firmware will be provided.
 129  *
 130  *      Note: zero means 'wait forever'.
 131  **/
 132 static ssize_t firmware_timeout_store(struct class *class,
 133                                       const char *buf, size_t count)
 134 {
 135         loading_timeout = simple_strtol(buf, NULL, 10);
 136         if (loading_timeout < 0)
 137                 loading_timeout = 0;
 138
 139         return count;
 140 }
 141
 142 static struct class_attribute firmware_class_attrs[] = {
 143         __ATTR(timeout, S_IWUSR | S_IRUGO,
 144                 firmware_timeout_show, firmware_timeout_store),
 145         __ATTR_NULL
 146 };
 147
 148 static void fw_dev_release(struct device *dev)
 149 {
 150         struct firmware_priv *fw_priv = to_firmware_priv(dev);
 151         int i;
 152
 153         for (i = 0; i < fw_priv->nr_pages; i++)
 154                 __free_page(fw_priv->pages[i]);
 155         kfree(fw_priv->pages);
 156         kfree(fw_priv);
 157
 158         module_put(THIS_MODULE);
 159 }
 160
 161 #if (LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,24))
 162 static int firmware_uevent(struct device *dev, struct kobj_uevent_env *env)
 163 {
 164         struct firmware_priv *fw_priv = to_firmware_priv(dev);
 165
 166         if (add_uevent_var(env, "FIRMWARE=%s", fw_priv->fw_id))
 167                 return -ENOMEM;
 168         if (add_uevent_var(env, "TIMEOUT=%i", loading_timeout))
 169                 return -ENOMEM;
 170         if (add_uevent_var(env, "ASYNC=%d", fw_priv->nowait))
 171                 return -ENOMEM;
 172
 173         return 0;
 174 }
 175 #else
 176 static int firmware_uevent(struct device *dev, char **envp,
 177                            int num_envp, char *buf, int size)
 178 {
 179         struct firmware_priv *fw_priv = to_firmware_priv(dev);
 180         int error, len = 0, i = 0;
 181
 182         error = add_uevent_var(envp, num_envp, &i,
 183                                buf, size, &len,
 184                                "FIRMWARE=%s", fw_priv->fw_id);
 185         if (error)
 186                 goto exit;
 187
 188         error = add_uevent_var(envp, num_envp, &i,
 189                                buf, size, &len,
 190                                "TIMEOUT=%i", loading_timeout);
 191         if (error)
 192                 goto exit;
 193         error = add_uevent_var(envp, num_envp, &i,
 194                                buf, size, &len,
 195                                "ASYNC=%i", fw_priv->nowait);
 196         if (error)
 197                 goto exit;
 198
 199         return 0;
 200 exit:
 201         envp[i] = NULL;
 202         return error;
 203 }
 204 #endif
 205
 206 static struct class firmware_class = {
 207         .name           = "compat_firmware",
 208         .class_attrs    = firmware_class_attrs,
 209         .dev_uevent     = firmware_uevent,
 210         .dev_release    = fw_dev_release,
 211 };
 212
 213 static ssize_t firmware_loading_show(struct device *dev,
 214                                      struct device_attribute *attr, char *buf)
 215 {
 216         struct firmware_priv *fw_priv = to_firmware_priv(dev);
 217         int loading = test_bit(FW_STATUS_LOADING, &fw_priv->status);
 218
 219         return sprintf(buf, "%d\n", loading);
 220 }
 221
 222 static void firmware_free_data(const struct firmware *fw)
 223 {
 224 #if (LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,35))
 225         int i;
 226         vunmap(fw->data);
 227         if (fw->pages) {
 228                 for (i = 0; i < PFN_UP(fw->size); i++)
 229                         __free_page(fw->pages[i]);
 230                 kfree(fw->pages);
 231         }
 232 #else
 233         vunmap(fw->data);
 234 #endif
 235 }
 236
 237 /* Some architectures don't have PAGE_KERNEL_RO */
 238 #ifndef PAGE_KERNEL_RO
 239 #define PAGE_KERNEL_RO PAGE_KERNEL
 240 #endif
 241 /**
 242  * firmware_loading_store - set value in the 'loading' control file
 243  * @dev: device pointer
 244  * @buf: buffer to scan for loading control value
 245  * @count: number of bytes in @buf
 246  *
 247  *      The relevant values are:
 248  *
 249  *       1: Start a load, discarding any previous partial load.
 250  *       0: Conclude the load and hand the data to the driver code.
 251  *      -1: Conclude the load with an error and discard any written data.
 252  **/
 253 static ssize_t firmware_loading_store(struct device *dev,
 254                                       struct device_attribute *attr,
 255                                       const char *buf, size_t count)
 256 {
 257         struct firmware_priv *fw_priv = to_firmware_priv(dev);
 258         int loading = simple_strtol(buf, NULL, 10);
 259         int i;
 260
 261         switch (loading) {
 262         case 1:
 263                 mutex_lock(&fw_lock);
 264                 if (!fw_priv->fw) {
 265                         mutex_unlock(&fw_lock);
 266                         break;
 267                 }
 268                 firmware_free_data(fw_priv->fw);
 269                 memset(fw_priv->fw, 0, sizeof(struct firmware));
 270                 /* If the pages are not owned by 'struct firmware' */
 271                 for (i = 0; i < fw_priv->nr_pages; i++)
 272                         __free_page(fw_priv->pages[i]);
 273                 kfree(fw_priv->pages);
 274                 fw_priv->pages = NULL;
 275                 fw_priv->page_array_size = 0;
 276                 fw_priv->nr_pages = 0;
 277                 set_bit(FW_STATUS_LOADING, &fw_priv->status);
 278                 mutex_unlock(&fw_lock);
 279                 break;
 280         case 0:
 281                 if (test_bit(FW_STATUS_LOADING, &fw_priv->status)) {
 282                         vunmap(fw_priv->fw->data);
 283                         fw_priv->fw->data = vmap(fw_priv->pages,
 284                                                  fw_priv->nr_pages,
 285                                                  0, PAGE_KERNEL_RO);
 286                         if (!fw_priv->fw->data) {
 287                                 dev_err(dev, "%s: vmap() failed\n", __func__);
 288                                 goto err;
 289                         }
 290                         /* Pages are now owned by 'struct firmware' */
 291 #if (LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,35))
 292                         fw_priv->fw->pages = fw_priv->pages;
 293                         fw_priv->pages = NULL;
 294 #endif
 295
 296                         fw_priv->page_array_size = 0;
 297                         fw_priv->nr_pages = 0;
 298                         complete(&fw_priv->completion);
 299                         clear_bit(FW_STATUS_LOADING, &fw_priv->status);
 300                         break;
 301                 }
 302                 /* fallthrough */
 303         default:
 304                 dev_err(dev, "%s: unexpected value (%d)\n", __func__, loading);
 305                 /* fallthrough */
 306         case -1:
 307         err:
 308                 fw_load_abort(fw_priv);
 309                 break;
 310         }
 311
 312         return count;
 313 }
 314
 315 static DEVICE_ATTR(loading, 0644, firmware_loading_show, firmware_loading_store);
 316
 317 #if defined(CONFIG_COMPAT_FIRMWARE_DATA_RW_NEEDS_FILP)
 318 static ssize_t firmware_data_read(struct file *filp, struct kobject *kobj,
 319                                   struct bin_attribute *bin_attr,
 320                                   char *buffer, loff_t offset, size_t count)
 321 #else
 322 static ssize_t firmware_data_read(struct kobject *kobj,
 323                                   struct bin_attribute *bin_attr,
 324                                   char *buffer, loff_t offset, size_t count)
 325 #endif
 326 {
 327         struct device *dev = compat_firmware_to_dev(kobj);
 328         struct firmware_priv *fw_priv = to_firmware_priv(dev);
 329         struct firmware *fw;
 330         ssize_t ret_count;
 331
 332         mutex_lock(&fw_lock);
 333         fw = fw_priv->fw;
 334         if (!fw || test_bit(FW_STATUS_DONE, &fw_priv->status)) {
 335                 ret_count = -ENODEV;
 336                 goto out;
 337         }
 338         if (offset > fw->size) {
 339                 ret_count = 0;
 340                 goto out;
 341         }
 342         if (count > fw->size - offset)
 343                 count = fw->size - offset;
 344
 345         ret_count = count;
 346
 347         while (count) {
 348                 void *page_data;
 349                 int page_nr = offset >> PAGE_SHIFT;
 350                 int page_ofs = offset & (PAGE_SIZE-1);
 351                 int page_cnt = min_t(size_t, PAGE_SIZE - page_ofs, count);
 352
 353                 page_data = kmap(fw_priv->pages[page_nr]);
 354
 355                 memcpy(buffer, page_data + page_ofs, page_cnt);
 356
 357                 kunmap(fw_priv->pages[page_nr]);
 358                 buffer += page_cnt;
 359                 offset += page_cnt;
 360                 count -= page_cnt;
 361         }
 362 out:
 363         mutex_unlock(&fw_lock);
 364         return ret_count;
 365 }
 366
 367 static int fw_realloc_buffer(struct firmware_priv *fw_priv, int min_size)
 368 {
 369         int pages_needed = ALIGN(min_size, PAGE_SIZE) >> PAGE_SHIFT;
 370
 371         /* If the array of pages is too small, grow it... */
 372         if (fw_priv->page_array_size < pages_needed) {
 373                 int new_array_size = max(pages_needed,
 374                                          fw_priv->page_array_size * 2);
 375                 struct page **new_pages;
 376
 377                 new_pages = kmalloc(new_array_size * sizeof(void *),
 378                                     GFP_KERNEL);
 379                 if (!new_pages) {
 380                         fw_load_abort(fw_priv);
 381                         return -ENOMEM;
 382                 }
 383                 memcpy(new_pages, fw_priv->pages,
 384                        fw_priv->page_array_size * sizeof(void *));
 385                 memset(&new_pages[fw_priv->page_array_size], 0, sizeof(void *) *
 386                        (new_array_size - fw_priv->page_array_size));
 387                 kfree(fw_priv->pages);
 388                 fw_priv->pages = new_pages;
 389                 fw_priv->page_array_size = new_array_size;
 390         }
 391
 392         while (fw_priv->nr_pages < pages_needed) {
 393                 fw_priv->pages[fw_priv->nr_pages] =
 394                         alloc_page(GFP_KERNEL | __GFP_HIGHMEM);
 395
 396                 if (!fw_priv->pages[fw_priv->nr_pages]) {
 397                         fw_load_abort(fw_priv);
 398                         return -ENOMEM;
 399                 }
 400                 fw_priv->nr_pages++;
 401         }
 402         return 0;
 403 }
 404
 405 /**
 406  * firmware_data_write - write method for firmware
 407  * @kobj: kobject for the device
 408  * @bin_attr: bin_attr structure
 409  * @buffer: buffer being written
 410  * @offset: buffer offset for write in total data store area
 411  * @count: buffer size
 412  *
 413  *      Data written to the 'data' attribute will be later handed to
 414  *      the driver as a firmware image.
 415  **/
 416 #if defined(CONFIG_COMPAT_FIRMWARE_DATA_RW_NEEDS_FILP)
 417 static ssize_t firmware_data_write(struct file *filp, struct kobject *kobj,
 418                                    struct bin_attribute *bin_attr,
 419                                    char *buffer, loff_t offset, size_t count)
 420 #else
 421 static ssize_t firmware_data_write(struct kobject *kobj,
 422                                    struct bin_attribute *bin_attr,
 423                                    char *buffer, loff_t offset, size_t count)
 424 #endif
 425 {
 426         struct device *dev = compat_firmware_to_dev(kobj);
 427         struct firmware_priv *fw_priv = to_firmware_priv(dev);
 428         struct firmware *fw;
 429         ssize_t retval;
 430
 431         if (!capable(CAP_SYS_RAWIO))
 432                 return -EPERM;
 433
 434         mutex_lock(&fw_lock);
 435         fw = fw_priv->fw;
 436         if (!fw || test_bit(FW_STATUS_DONE, &fw_priv->status)) {
 437                 retval = -ENODEV;
 438                 goto out;
 439         }
 440         retval = fw_realloc_buffer(fw_priv, offset + count);
 441         if (retval)
 442                 goto out;
 443
 444         retval = count;
 445
 446         while (count) {
 447                 void *page_data;
 448                 int page_nr = offset >> PAGE_SHIFT;
 449                 int page_ofs = offset & (PAGE_SIZE - 1);
 450                 int page_cnt = min_t(size_t, PAGE_SIZE - page_ofs, count);
 451
 452                 page_data = kmap(fw_priv->pages[page_nr]);
 453
 454                 memcpy(page_data + page_ofs, buffer, page_cnt);
 455
 456                 kunmap(fw_priv->pages[page_nr]);
 457                 buffer += page_cnt;
 458                 offset += page_cnt;
 459                 count -= page_cnt;
 460         }
 461
 462         fw->size = max_t(size_t, offset, fw->size);
 463 out:
 464         mutex_unlock(&fw_lock);
 465         return retval;
 466 }
 467
 468 static struct bin_attribute firmware_attr_data = {
 469         .attr = { .name = "data", .mode = 0644 },
 470         .size = 0,
 471         .read = firmware_data_read,
 472         .write = firmware_data_write,
 473 };
 474
 475 static void firmware_class_timeout(u_long data)
 476 {
 477         struct firmware_priv *fw_priv = (struct firmware_priv *) data;
 478
 479         fw_load_abort(fw_priv);
 480 }
 481
 482 static struct firmware_priv *
 483 fw_create_instance(struct firmware *firmware, const char *fw_name,
 484                    struct device *device, bool uevent, bool nowait)
 485 {
 486         struct firmware_priv *fw_priv;
 487         struct device *f_dev;
 488         int error;
 489
 490         fw_priv = kzalloc(sizeof(*fw_priv) + strlen(fw_name) + 1 , GFP_KERNEL);
 491         if (!fw_priv) {
 492                 dev_err(device, "%s: kmalloc failed\n", __func__);
 493                 error = -ENOMEM;
 494                 goto err_out;
 495         }
 496
 497         fw_priv->fw = firmware;
 498         fw_priv->nowait = nowait;
 499         strcpy(fw_priv->fw_id, fw_name);
 500         init_completion(&fw_priv->completion);
 501         setup_timer(&fw_priv->timeout,
 502                     firmware_class_timeout, (u_long) fw_priv);
 503
 504         f_dev = &fw_priv->dev;
 505
 506         device_initialize(f_dev);
 507         dev_set_name(f_dev, "%s", dev_name(device));
 508         f_dev->parent = device;
 509         f_dev->class = &firmware_class;
 510
 511         dev_set_uevent_suppress(f_dev, true);
 512
 513         /* Need to pin this module until class device is destroyed */
 514         __module_get(THIS_MODULE);
 515
 516         error = device_add(f_dev);
 517         if (error) {
 518                 dev_err(device, "%s: device_register failed\n", __func__);
 519                 goto err_put_dev;
 520         }
 521
 522         error = device_create_bin_file(f_dev, &firmware_attr_data);
 523         if (error) {
 524                 dev_err(device, "%s: sysfs_create_bin_file failed\n", __func__);
 525                 goto err_del_dev;
 526         }
 527
 528         error = device_create_file(f_dev, &dev_attr_loading);
 529         if (error) {
 530                 dev_err(device, "%s: device_create_file failed\n", __func__);
 531                 goto err_del_bin_attr;
 532         }
 533
 534         if (uevent)
 535                 dev_set_uevent_suppress(f_dev, false);
 536
 537         return fw_priv;
 538
 539 err_del_bin_attr:
 540         device_remove_bin_file(f_dev, &firmware_attr_data);
 541 err_del_dev:
 542         device_del(f_dev);
 543 err_put_dev:
 544         put_device(f_dev);
 545 err_out:
 546         return ERR_PTR(error);
 547 }
 548
 549 static void fw_destroy_instance(struct firmware_priv *fw_priv)
 550 {
 551         struct device *f_dev = &fw_priv->dev;
 552
 553         device_remove_file(f_dev, &dev_attr_loading);
 554         device_remove_bin_file(f_dev, &firmware_attr_data);
 555         device_unregister(f_dev);
 556 }
 557
 558 static int _request_firmware(const struct firmware **firmware_p,
 559                              const char *name, struct device *device,
 560                              bool uevent, bool nowait)
 561 {
 562         struct firmware_priv *fw_priv;
 563         struct firmware *firmware;
 564         int retval = 0;
 565
 566         if (!firmware_p)
 567                 return -EINVAL;
 568
 569         *firmware_p = firmware = kzalloc(sizeof(*firmware), GFP_KERNEL);
 570         if (!firmware) {
 571                 dev_err(device, "%s: kmalloc(struct firmware) failed\n",
 572                         __func__);
 573                 retval = -ENOMEM;
 574                 goto out;
 575         }
 576
 577         if (fw_get_builtin_firmware(firmware, name)) {
 578                 dev_dbg(device, "firmware: using built-in firmware %s\n", name);
 579                 return 0;
 580         }
 581
 582         if (uevent)
 583                 dev_dbg(device, "firmware: requesting %s\n", name);
 584
 585         fw_priv = fw_create_instance(firmware, name, device, uevent, nowait);
 586         if (IS_ERR(fw_priv)) {
 587                 retval = PTR_ERR(fw_priv);
 588                 goto out;
 589         }
 590
 591         if (uevent) {
 592                 if (loading_timeout > 0)
 593                         mod_timer(&fw_priv->timeout,
 594                                   round_jiffies_up(jiffies +
 595                                                    loading_timeout * HZ));
 596
 597                 kobject_uevent(&fw_priv->dev.kobj, KOBJ_ADD);
 598         }
 599
 600         wait_for_completion(&fw_priv->completion);
 601
 602         set_bit(FW_STATUS_DONE, &fw_priv->status);
 603         del_timer_sync(&fw_priv->timeout);
 604
 605         mutex_lock(&fw_lock);
 606         if (!fw_priv->fw->size || test_bit(FW_STATUS_ABORT, &fw_priv->status))
 607                 retval = -ENOENT;
 608         fw_priv->fw = NULL;
 609         mutex_unlock(&fw_lock);
 610
 611         fw_destroy_instance(fw_priv);
 612
 613 out:
 614         if (retval) {
 615                 release_firmware(firmware);
 616                 *firmware_p = NULL;
 617         }
 618
 619         return retval;
 620 }
 621
 622 /**
 623  * request_firmware: - send firmware request and wait for it
 624  * @firmware_p: pointer to firmware image
 625  * @name: name of firmware file
 626  * @device: device for which firmware is being loaded
 627  *
 628  *      @firmware_p will be used to return a firmware image by the name
 629  *      of @name for device @device.
 630  *
 631  *      Should be called from user context where sleeping is allowed.
 632  *
 633  *      @name will be used as $FIRMWARE in the uevent environment and
 634  *      should be distinctive enough not to be confused with any other
 635  *      firmware image for this or any other device.
 636  **/
 637 int
 638 request_firmware(const struct firmware **firmware_p, const char *name,
 639                  struct device *device)
 640 {
 641         int uevent = 1;
 642         return _request_firmware(firmware_p, name, device, uevent, false);
 643 }
 644
 645 /**
 646  * release_firmware: - release the resource associated with a firmware image
 647  * @fw: firmware resource to release
 648  **/
 649 void release_firmware(const struct firmware *fw)
 650 {
 651         if (fw) {
 652                 if (!fw_is_builtin_firmware(fw))
 653                         firmware_free_data(fw);
 654                 kfree(fw);
 655         }
 656 }
 657
 658 /* Async support */
 659 struct firmware_work {
 660         struct work_struct work;
 661         struct module *module;
 662         const char *name;
 663         struct device *device;
 664         void *context;
 665         void (*cont)(const struct firmware *fw, void *context);
 666         int uevent;
 667 };
 668
 669 static int request_firmware_work_func(void *arg)
 670 {
 671         struct firmware_work *fw_work = arg;
 672         const struct firmware *fw;
 673         int ret;
 674
 675         if (!arg) {
 676                 WARN_ON(1);
 677                 return 0;
 678         }
 679
 680         ret = _request_firmware(&fw, fw_work->name, fw_work->device,
 681                                 fw_work->uevent, true);
 682         fw_work->cont(fw, fw_work->context);
 683
 684         module_put(fw_work->module);
 685         kfree(fw_work);
 686
 687         return ret;
 688 }
 689
 690 /**
 691  * request_firmware_nowait - asynchronous version of request_firmware
 692  * @module: module requesting the firmware
 693  * @uevent: sends uevent to copy the firmware image if this flag
 694  *      is non-zero else the firmware copy must be done manually.
 695  * @name: name of firmware file
 696  * @device: device for which firmware is being loaded
 697  * @gfp: allocation flags
 698  * @context: will be passed over to @cont, and
 699  *      @fw may be %NULL if firmware request fails.
 700  * @cont: function will be called asynchronously when the firmware
 701  *      request is over.
 702  *
 703  *      Asynchronous variant of request_firmware() for user contexts where
 704  *      it is not possible to sleep for long time. It can't be called
 705  *      in atomic contexts.
 706  **/
 707 int
 708 request_firmware_nowait(
 709         struct module *module, int uevent,
 710         const char *name, struct device *device, gfp_t gfp, void *context,
 711         void (*cont)(const struct firmware *fw, void *context))
 712 {
 713         struct task_struct *task;
 714         struct firmware_work *fw_work;
 715
 716         fw_work = kzalloc(sizeof (struct firmware_work), gfp);
 717         if (!fw_work)
 718                 return -ENOMEM;
 719
 720         fw_work->module = module;
 721         fw_work->name = name;
 722         fw_work->device = device;
 723         fw_work->context = context;
 724         fw_work->cont = cont;
 725         fw_work->uevent = uevent;
 726
 727         if (!try_module_get(module)) {
 728                 kfree(fw_work);
 729                 return -EFAULT;
 730         }
 731
 732         task = kthread_run(request_firmware_work_func, fw_work,
 733                             "firmware/%s", name);
 734         if (IS_ERR(task)) {
 735                 fw_work->cont(NULL, fw_work->context);
 736                 module_put(fw_work->module);
 737                 kfree(fw_work);
 738                 return PTR_ERR(task);
 739         }
 740
 741         return 0;
 742 }
 743
 744 static int __init firmware_class_init(void)
 745 {
 746         return class_register(&firmware_class);
 747 }
 748
 749 static void __exit firmware_class_exit(void)
 750 {
 751         class_unregister(&firmware_class);
 752 }
 753
 754 fs_initcall(firmware_class_init);
 755 module_exit(firmware_class_exit);
 756
 757 EXPORT_SYMBOL_GPL(release_firmware);
 758 EXPORT_SYMBOL_GPL(request_firmware);
 759 EXPORT_SYMBOL_GPL(request_firmware_nowait);