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/workqueue.h>
  20 #include <linux/highmem.h>
  21 #include <linux/firmware.h>
  22 #include <linux/slab.h>
  23 #include <linux/sched.h>
  24 #include <linux/file.h>
  25 #include <linux/list.h>
  26 #include <linux/async.h>
  27 #include <linux/pm.h>
  28 #include <linux/suspend.h>
  29 #include <linux/syscore_ops.h>
  30
  31 #include <generated/utsrelease.h>
  32
  33 #include "base.h"
  34
  35 #define to_dev(obj) container_of(obj, struct device, kobj)
  36
  37 MODULE_AUTHOR("Manuel Estrada Sainz");
  38 MODULE_DESCRIPTION("Multi purpose firmware loading support");
  39 MODULE_LICENSE("GPL");
  40
  41 static const char *fw_path[] = {
  42         "/lib/firmware/updates/" UTS_RELEASE,
  43         "/lib/firmware/updates",
  44         "/lib/firmware/" UTS_RELEASE,
  45         "/lib/firmware"
  46 };
  47
  48 /* Don't inline this: 'struct kstat' is biggish */
  49 static noinline long fw_file_size(struct file *file)
  50 {
  51         struct kstat st;
  52         if (vfs_getattr(file->f_path.mnt, file->f_path.dentry, &st))
  53                 return -1;
  54         if (!S_ISREG(st.mode))
  55                 return -1;
  56         if (st.size != (long)st.size)
  57                 return -1;
  58         return st.size;
  59 }
  60
  61 static bool fw_read_file_contents(struct file *file, struct firmware *fw)
  62 {
  63         long size;
  64         char *buf;
  65
  66         size = fw_file_size(file);
  67         if (size < 0)
  68                 return false;
  69         buf = vmalloc(size);
  70         if (!buf)
  71                 return false;
  72         if (kernel_read(file, 0, buf, size) != size) {
  73                 vfree(buf);
  74                 return false;
  75         }
  76         fw->data = buf;
  77         fw->size = size;
  78         return true;
  79 }
  80
  81 static bool fw_get_filesystem_firmware(struct firmware *fw, const char *name)
  82 {
  83         int i;
  84         bool success = false;
  85         char *path = __getname();
  86
  87         for (i = 0; i < ARRAY_SIZE(fw_path); i++) {
  88                 struct file *file;
  89                 snprintf(path, PATH_MAX, "%s/%s", fw_path[i], name);
  90
  91                 file = filp_open(path, O_RDONLY, 0);
  92                 if (IS_ERR(file))
  93                         continue;
  94                 success = fw_read_file_contents(file, fw);
  95                 fput(file);
  96                 if (success)
  97                         break;
  98         }
  99         __putname(path);
 100         return success;
 101 }
 102
 103 /* Builtin firmware support */
 104
 105 #ifdef CONFIG_FW_LOADER
 106
 107 extern struct builtin_fw __start_builtin_fw[];
 108 extern struct builtin_fw __end_builtin_fw[];
 109
 110 static bool fw_get_builtin_firmware(struct firmware *fw, const char *name)
 111 {
 112         struct builtin_fw *b_fw;
 113
 114         for (b_fw = __start_builtin_fw; b_fw != __end_builtin_fw; b_fw++) {
 115                 if (strcmp(name, b_fw->name) == 0) {
 116                         fw->size = b_fw->size;
 117                         fw->data = b_fw->data;
 118                         return true;
 119                 }
 120         }
 121
 122         return false;
 123 }
 124
 125 static bool fw_is_builtin_firmware(const struct firmware *fw)
 126 {
 127         struct builtin_fw *b_fw;
 128
 129         for (b_fw = __start_builtin_fw; b_fw != __end_builtin_fw; b_fw++)
 130                 if (fw->data == b_fw->data)
 131                         return true;
 132
 133         return false;
 134 }
 135
 136 #else /* Module case - no builtin firmware support */
 137
 138 static inline bool fw_get_builtin_firmware(struct firmware *fw, const char *name)
 139 {
 140         return false;
 141 }
 142
 143 static inline bool fw_is_builtin_firmware(const struct firmware *fw)
 144 {
 145         return false;
 146 }
 147 #endif
 148
 149 enum {
 150         FW_STATUS_LOADING,
 151         FW_STATUS_DONE,
 152         FW_STATUS_ABORT,
 153 };
 154
 155 static int loading_timeout = 60;        /* In seconds */
 156
 157 static inline long firmware_loading_timeout(void)
 158 {
 159         return loading_timeout > 0 ? loading_timeout * HZ : MAX_SCHEDULE_TIMEOUT;
 160 }
 161
 162 /* fw_lock could be moved to 'struct firmware_priv' but since it is just
 163  * guarding for corner cases a global lock should be OK */
 164 static DEFINE_MUTEX(fw_lock);
 165
 166 struct firmware_priv {
 167         struct completion completion;
 168         struct firmware *fw;
 169         unsigned long status;
 170         struct page **pages;
 171         int nr_pages;
 172         int page_array_size;
 173         struct timer_list timeout;
 174         struct device dev;
 175         bool nowait;
 176         char fw_id[];
 177 };
 178
 179 static struct firmware_priv *to_firmware_priv(struct device *dev)
 180 {
 181         return container_of(dev, struct firmware_priv, dev);
 182 }
 183
 184 static void fw_load_abort(struct firmware_priv *fw_priv)
 185 {
 186         set_bit(FW_STATUS_ABORT, &fw_priv->status);
 187         wmb();
 188         complete(&fw_priv->completion);
 189 }
 190
 191 static ssize_t firmware_timeout_show(struct class *class,
 192                                      struct class_attribute *attr,
 193                                      char *buf)
 194 {
 195         return sprintf(buf, "%d\n", loading_timeout);
 196 }
 197
 198 /**
 199  * firmware_timeout_store - set number of seconds to wait for firmware
 200  * @class: device class pointer
 201  * @attr: device attribute pointer
 202  * @buf: buffer to scan for timeout value
 203  * @count: number of bytes in @buf
 204  *
 205  *      Sets the number of seconds to wait for the firmware.  Once
 206  *      this expires an error will be returned to the driver and no
 207  *      firmware will be provided.
 208  *
 209  *      Note: zero means 'wait forever'.
 210  **/
 211 static ssize_t firmware_timeout_store(struct class *class,
 212                                       struct class_attribute *attr,
 213                                       const char *buf, size_t count)
 214 {
 215         loading_timeout = simple_strtol(buf, NULL, 10);
 216         if (loading_timeout < 0)
 217                 loading_timeout = 0;
 218
 219         return count;
 220 }
 221
 222 static struct class_attribute firmware_class_attrs[] = {
 223         __ATTR(timeout, S_IWUSR | S_IRUGO,
 224                 firmware_timeout_show, firmware_timeout_store),
 225         __ATTR_NULL
 226 };
 227
 228 static void fw_dev_release(struct device *dev)
 229 {
 230         struct firmware_priv *fw_priv = to_firmware_priv(dev);
 231         int i;
 232
 233         for (i = 0; i < fw_priv->nr_pages; i++)
 234                 __free_page(fw_priv->pages[i]);
 235         kfree(fw_priv->pages);
 236         kfree(fw_priv);
 237
 238         module_put(THIS_MODULE);
 239 }
 240
 241 static int firmware_uevent(struct device *dev, struct kobj_uevent_env *env)
 242 {
 243         struct firmware_priv *fw_priv = to_firmware_priv(dev);
 244
 245         if (add_uevent_var(env, "FIRMWARE=%s", fw_priv->fw_id))
 246                 return -ENOMEM;
 247         if (add_uevent_var(env, "TIMEOUT=%i", loading_timeout))
 248                 return -ENOMEM;
 249         if (add_uevent_var(env, "ASYNC=%d", fw_priv->nowait))
 250                 return -ENOMEM;
 251
 252         return 0;
 253 }
 254
 255 static struct class firmware_class = {
 256         .name           = "firmware",
 257         .class_attrs    = firmware_class_attrs,
 258         .dev_uevent     = firmware_uevent,
 259         .dev_release    = fw_dev_release,
 260 };
 261
 262 static ssize_t firmware_loading_show(struct device *dev,
 263                                      struct device_attribute *attr, char *buf)
 264 {
 265         struct firmware_priv *fw_priv = to_firmware_priv(dev);
 266         int loading = test_bit(FW_STATUS_LOADING, &fw_priv->status);
 267
 268         return sprintf(buf, "%d\n", loading);
 269 }
 270
 271 static void firmware_free_data(const struct firmware *fw)
 272 {
 273         int i;
 274         if (fw->pages) {
 275                 vunmap(fw->data);
 276                 for (i = 0; i < PFN_UP(fw->size); i++)
 277                         __free_page(fw->pages[i]);
 278                 kfree(fw->pages);
 279         /* Loaded directly? */
 280         } else {
 281                 vfree(fw->data);
 282         }
 283 }
 284
 285 /* Some architectures don't have PAGE_KERNEL_RO */
 286 #ifndef PAGE_KERNEL_RO
 287 #define PAGE_KERNEL_RO PAGE_KERNEL
 288 #endif
 289 /**
 290  * firmware_loading_store - set value in the 'loading' control file
 291  * @dev: device pointer
 292  * @attr: device attribute pointer
 293  * @buf: buffer to scan for loading control value
 294  * @count: number of bytes in @buf
 295  *
 296  *      The relevant values are:
 297  *
 298  *       1: Start a load, discarding any previous partial load.
 299  *       0: Conclude the load and hand the data to the driver code.
 300  *      -1: Conclude the load with an error and discard any written data.
 301  **/
 302 static ssize_t firmware_loading_store(struct device *dev,
 303                                       struct device_attribute *attr,
 304                                       const char *buf, size_t count)
 305 {
 306         struct firmware_priv *fw_priv = to_firmware_priv(dev);
 307         int loading = simple_strtol(buf, NULL, 10);
 308         int i;
 309
 310         mutex_lock(&fw_lock);
 311
 312         if (!fw_priv->fw)
 313                 goto out;
 314
 315         switch (loading) {
 316         case 1:
 317                 firmware_free_data(fw_priv->fw);
 318                 memset(fw_priv->fw, 0, sizeof(struct firmware));
 319                 /* If the pages are not owned by 'struct firmware' */
 320                 for (i = 0; i < fw_priv->nr_pages; i++)
 321                         __free_page(fw_priv->pages[i]);
 322                 kfree(fw_priv->pages);
 323                 fw_priv->pages = NULL;
 324                 fw_priv->page_array_size = 0;
 325                 fw_priv->nr_pages = 0;
 326                 set_bit(FW_STATUS_LOADING, &fw_priv->status);
 327                 break;
 328         case 0:
 329                 if (test_bit(FW_STATUS_LOADING, &fw_priv->status)) {
 330                         vunmap(fw_priv->fw->data);
 331                         fw_priv->fw->data = vmap(fw_priv->pages,
 332                                                  fw_priv->nr_pages,
 333                                                  0, PAGE_KERNEL_RO);
 334                         if (!fw_priv->fw->data) {
 335                                 dev_err(dev, "%s: vmap() failed\n", __func__);
 336                                 goto err;
 337                         }
 338                         /* Pages are now owned by 'struct firmware' */
 339                         fw_priv->fw->pages = fw_priv->pages;
 340                         fw_priv->pages = NULL;
 341
 342                         fw_priv->page_array_size = 0;
 343                         fw_priv->nr_pages = 0;
 344                         complete(&fw_priv->completion);
 345                         clear_bit(FW_STATUS_LOADING, &fw_priv->status);
 346                         break;
 347                 }
 348                 /* fallthrough */
 349         default:
 350                 dev_err(dev, "%s: unexpected value (%d)\n", __func__, loading);
 351                 /* fallthrough */
 352         case -1:
 353         err:
 354                 fw_load_abort(fw_priv);
 355                 break;
 356         }
 357 out:
 358         mutex_unlock(&fw_lock);
 359         return count;
 360 }
 361
 362 static DEVICE_ATTR(loading, 0644, firmware_loading_show, firmware_loading_store);
 363
 364 static ssize_t firmware_data_read(struct file *filp, struct kobject *kobj,
 365                                   struct bin_attribute *bin_attr,
 366                                   char *buffer, loff_t offset, size_t count)
 367 {
 368         struct device *dev = to_dev(kobj);
 369         struct firmware_priv *fw_priv = to_firmware_priv(dev);
 370         struct firmware *fw;
 371         ssize_t ret_count;
 372
 373         mutex_lock(&fw_lock);
 374         fw = fw_priv->fw;
 375         if (!fw || test_bit(FW_STATUS_DONE, &fw_priv->status)) {
 376                 ret_count = -ENODEV;
 377                 goto out;
 378         }
 379         if (offset > fw->size) {
 380                 ret_count = 0;
 381                 goto out;
 382         }
 383         if (count > fw->size - offset)
 384                 count = fw->size - offset;
 385
 386         ret_count = count;
 387
 388         while (count) {
 389                 void *page_data;
 390                 int page_nr = offset >> PAGE_SHIFT;
 391                 int page_ofs = offset & (PAGE_SIZE-1);
 392                 int page_cnt = min_t(size_t, PAGE_SIZE - page_ofs, count);
 393
 394                 page_data = kmap(fw_priv->pages[page_nr]);
 395
 396                 memcpy(buffer, page_data + page_ofs, page_cnt);
 397
 398                 kunmap(fw_priv->pages[page_nr]);
 399                 buffer += page_cnt;
 400                 offset += page_cnt;
 401                 count -= page_cnt;
 402         }
 403 out:
 404         mutex_unlock(&fw_lock);
 405         return ret_count;
 406 }
 407
 408 static int fw_realloc_buffer(struct firmware_priv *fw_priv, int min_size)
 409 {
 410         int pages_needed = ALIGN(min_size, PAGE_SIZE) >> PAGE_SHIFT;
 411
 412         /* If the array of pages is too small, grow it... */
 413         if (fw_priv->page_array_size < pages_needed) {
 414                 int new_array_size = max(pages_needed,
 415                                          fw_priv->page_array_size * 2);
 416                 struct page **new_pages;
 417
 418                 new_pages = kmalloc(new_array_size * sizeof(void *),
 419                                     GFP_KERNEL);
 420                 if (!new_pages) {
 421                         fw_load_abort(fw_priv);
 422                         return -ENOMEM;
 423                 }
 424                 memcpy(new_pages, fw_priv->pages,
 425                        fw_priv->page_array_size * sizeof(void *));
 426                 memset(&new_pages[fw_priv->page_array_size], 0, sizeof(void *) *
 427                        (new_array_size - fw_priv->page_array_size));
 428                 kfree(fw_priv->pages);
 429                 fw_priv->pages = new_pages;
 430                 fw_priv->page_array_size = new_array_size;
 431         }
 432
 433         while (fw_priv->nr_pages < pages_needed) {
 434                 fw_priv->pages[fw_priv->nr_pages] =
 435                         alloc_page(GFP_KERNEL | __GFP_HIGHMEM);
 436
 437                 if (!fw_priv->pages[fw_priv->nr_pages]) {
 438                         fw_load_abort(fw_priv);
 439                         return -ENOMEM;
 440                 }
 441                 fw_priv->nr_pages++;
 442         }
 443         return 0;
 444 }
 445
 446 /**
 447  * firmware_data_write - write method for firmware
 448  * @filp: open sysfs file
 449  * @kobj: kobject for the device
 450  * @bin_attr: bin_attr structure
 451  * @buffer: buffer being written
 452  * @offset: buffer offset for write in total data store area
 453  * @count: buffer size
 454  *
 455  *      Data written to the 'data' attribute will be later handed to
 456  *      the driver as a firmware image.
 457  **/
 458 static ssize_t firmware_data_write(struct file *filp, struct kobject *kobj,
 459                                    struct bin_attribute *bin_attr,
 460                                    char *buffer, loff_t offset, size_t count)
 461 {
 462         struct device *dev = to_dev(kobj);
 463         struct firmware_priv *fw_priv = to_firmware_priv(dev);
 464         struct firmware *fw;
 465         ssize_t retval;
 466
 467         if (!capable(CAP_SYS_RAWIO))
 468                 return -EPERM;
 469
 470         mutex_lock(&fw_lock);
 471         fw = fw_priv->fw;
 472         if (!fw || test_bit(FW_STATUS_DONE, &fw_priv->status)) {
 473                 retval = -ENODEV;
 474                 goto out;
 475         }
 476         retval = fw_realloc_buffer(fw_priv, offset + count);
 477         if (retval)
 478                 goto out;
 479
 480         retval = count;
 481
 482         while (count) {
 483                 void *page_data;
 484                 int page_nr = offset >> PAGE_SHIFT;
 485                 int page_ofs = offset & (PAGE_SIZE - 1);
 486                 int page_cnt = min_t(size_t, PAGE_SIZE - page_ofs, count);
 487
 488                 page_data = kmap(fw_priv->pages[page_nr]);
 489
 490                 memcpy(page_data + page_ofs, buffer, page_cnt);
 491
 492                 kunmap(fw_priv->pages[page_nr]);
 493                 buffer += page_cnt;
 494                 offset += page_cnt;
 495                 count -= page_cnt;
 496         }
 497
 498         fw->size = max_t(size_t, offset, fw->size);
 499 out:
 500         mutex_unlock(&fw_lock);
 501         return retval;
 502 }
 503
 504 static struct bin_attribute firmware_attr_data = {
 505         .attr = { .name = "data", .mode = 0644 },
 506         .size = 0,
 507         .read = firmware_data_read,
 508         .write = firmware_data_write,
 509 };
 510
 511 static void firmware_class_timeout(u_long data)
 512 {
 513         struct firmware_priv *fw_priv = (struct firmware_priv *) data;
 514
 515         fw_load_abort(fw_priv);
 516 }
 517
 518 static struct firmware_priv *
 519 fw_create_instance(struct firmware *firmware, const char *fw_name,
 520                    struct device *device, bool uevent, bool nowait)
 521 {
 522         struct firmware_priv *fw_priv;
 523         struct device *f_dev;
 524
 525         fw_priv = kzalloc(sizeof(*fw_priv) + strlen(fw_name) + 1 , GFP_KERNEL);
 526         if (!fw_priv) {
 527                 dev_err(device, "%s: kmalloc failed\n", __func__);
 528                 return ERR_PTR(-ENOMEM);
 529         }
 530
 531         fw_priv->fw = firmware;
 532         fw_priv->nowait = nowait;
 533         strcpy(fw_priv->fw_id, fw_name);
 534         init_completion(&fw_priv->completion);
 535         setup_timer(&fw_priv->timeout,
 536                     firmware_class_timeout, (u_long) fw_priv);
 537
 538         f_dev = &fw_priv->dev;
 539
 540         device_initialize(f_dev);
 541         dev_set_name(f_dev, "%s", dev_name(device));
 542         f_dev->parent = device;
 543         f_dev->class = &firmware_class;
 544
 545         return fw_priv;
 546 }
 547
 548 static struct firmware_priv *
 549 _request_firmware_prepare(const struct firmware **firmware_p, const char *name,
 550                           struct device *device, bool uevent, bool nowait)
 551 {
 552         struct firmware *firmware;
 553         struct firmware_priv *fw_priv;
 554
 555         if (!firmware_p)
 556                 return ERR_PTR(-EINVAL);
 557
 558         *firmware_p = firmware = kzalloc(sizeof(*firmware), GFP_KERNEL);
 559         if (!firmware) {
 560                 dev_err(device, "%s: kmalloc(struct firmware) failed\n",
 561                         __func__);
 562                 return ERR_PTR(-ENOMEM);
 563         }
 564
 565         if (fw_get_builtin_firmware(firmware, name)) {
 566                 dev_dbg(device, "firmware: using built-in firmware %s\n", name);
 567                 return NULL;
 568         }
 569
 570         if (fw_get_filesystem_firmware(firmware, name)) {
 571                 dev_dbg(device, "firmware: direct-loading firmware %s\n", name);
 572                 return NULL;
 573         }
 574
 575         fw_priv = fw_create_instance(firmware, name, device, uevent, nowait);
 576         if (IS_ERR(fw_priv)) {
 577                 release_firmware(firmware);
 578                 *firmware_p = NULL;
 579         }
 580         return fw_priv;
 581 }
 582
 583 static void _request_firmware_cleanup(const struct firmware **firmware_p)
 584 {
 585         release_firmware(*firmware_p);
 586         *firmware_p = NULL;
 587 }
 588
 589 static int _request_firmware_load(struct firmware_priv *fw_priv, bool uevent,
 590                                   long timeout)
 591 {
 592         int retval = 0;
 593         struct device *f_dev = &fw_priv->dev;
 594
 595         dev_set_uevent_suppress(f_dev, true);
 596
 597         /* Need to pin this module until class device is destroyed */
 598         __module_get(THIS_MODULE);
 599
 600         retval = device_add(f_dev);
 601         if (retval) {
 602                 dev_err(f_dev, "%s: device_register failed\n", __func__);
 603                 goto err_put_dev;
 604         }
 605
 606         retval = device_create_bin_file(f_dev, &firmware_attr_data);
 607         if (retval) {
 608                 dev_err(f_dev, "%s: sysfs_create_bin_file failed\n", __func__);
 609                 goto err_del_dev;
 610         }
 611
 612         retval = device_create_file(f_dev, &dev_attr_loading);
 613         if (retval) {
 614                 dev_err(f_dev, "%s: device_create_file failed\n", __func__);
 615                 goto err_del_bin_attr;
 616         }
 617
 618         if (uevent) {
 619                 dev_set_uevent_suppress(f_dev, false);
 620                 dev_dbg(f_dev, "firmware: requesting %s\n", fw_priv->fw_id);
 621                 if (timeout != MAX_SCHEDULE_TIMEOUT)
 622                         mod_timer(&fw_priv->timeout,
 623                                   round_jiffies_up(jiffies + timeout));
 624
 625                 kobject_uevent(&fw_priv->dev.kobj, KOBJ_ADD);
 626         }
 627
 628         wait_for_completion(&fw_priv->completion);
 629
 630         set_bit(FW_STATUS_DONE, &fw_priv->status);
 631         del_timer_sync(&fw_priv->timeout);
 632
 633         mutex_lock(&fw_lock);
 634         if (!fw_priv->fw->size || test_bit(FW_STATUS_ABORT, &fw_priv->status))
 635                 retval = -ENOENT;
 636         fw_priv->fw = NULL;
 637         mutex_unlock(&fw_lock);
 638
 639         device_remove_file(f_dev, &dev_attr_loading);
 640 err_del_bin_attr:
 641         device_remove_bin_file(f_dev, &firmware_attr_data);
 642 err_del_dev:
 643         device_del(f_dev);
 644 err_put_dev:
 645         put_device(f_dev);
 646         return retval;
 647 }
 648
 649 /**
 650  * request_firmware: - send firmware request and wait for it
 651  * @firmware_p: pointer to firmware image
 652  * @name: name of firmware file
 653  * @device: device for which firmware is being loaded
 654  *
 655  *      @firmware_p will be used to return a firmware image by the name
 656  *      of @name for device @device.
 657  *
 658  *      Should be called from user context where sleeping is allowed.
 659  *
 660  *      @name will be used as $FIRMWARE in the uevent environment and
 661  *      should be distinctive enough not to be confused with any other
 662  *      firmware image for this or any other device.
 663  **/
 664 int
 665 request_firmware(const struct firmware **firmware_p, const char *name,
 666                  struct device *device)
 667 {
 668         struct firmware_priv *fw_priv;
 669         int ret;
 670
 671         fw_priv = _request_firmware_prepare(firmware_p, name, device, true,
 672                                             false);
 673         if (IS_ERR_OR_NULL(fw_priv))
 674                 return PTR_RET(fw_priv);
 675
 676         ret = usermodehelper_read_trylock();
 677         if (ret) {
 678                 kfree(fw_priv);
 679                 dev_err(device, "firmware: %s will not be loaded\n", name);
 680         } else {
 681                 ret = _request_firmware_load(fw_priv, true,
 682                                         firmware_loading_timeout());
 683                 usermodehelper_read_unlock();
 684         }
 685         if (ret)
 686                 _request_firmware_cleanup(firmware_p);
 687
 688         return ret;
 689 }
 690
 691 /**
 692  * release_firmware: - release the resource associated with a firmware image
 693  * @fw: firmware resource to release
 694  **/
 695 void release_firmware(const struct firmware *fw)
 696 {
 697         if (fw) {
 698                 if (!fw_is_builtin_firmware(fw))
 699                         firmware_free_data(fw);
 700                 kfree(fw);
 701         }
 702 }
 703
 704 /* Async support */
 705 struct firmware_work {
 706         struct work_struct work;
 707         struct module *module;
 708         const char *name;
 709         struct device *device;
 710         void *context;
 711         void (*cont)(const struct firmware *fw, void *context);
 712         bool uevent;
 713 };
 714
 715 static void request_firmware_work_func(struct work_struct *work)
 716 {
 717         struct firmware_work *fw_work;
 718         const struct firmware *fw;
 719         struct firmware_priv *fw_priv;
 720         long timeout;
 721         int ret;
 722
 723         fw_work = container_of(work, struct firmware_work, work);
 724         fw_priv = _request_firmware_prepare(&fw, fw_work->name, fw_work->device,
 725                         fw_work->uevent, true);
 726         if (IS_ERR_OR_NULL(fw_priv)) {
 727                 ret = PTR_RET(fw_priv);
 728                 goto out;
 729         }
 730
 731         timeout = usermodehelper_read_lock_wait(firmware_loading_timeout());
 732         if (timeout) {
 733                 ret = _request_firmware_load(fw_priv, fw_work->uevent, timeout);
 734                 usermodehelper_read_unlock();
 735         } else {
 736                 dev_dbg(fw_work->device, "firmware: %s loading timed out\n",
 737                         fw_work->name);
 738                 ret = -EAGAIN;
 739         }
 740         if (ret)
 741                 _request_firmware_cleanup(&fw);
 742
 743  out:
 744         fw_work->cont(fw, fw_work->context);
 745
 746         module_put(fw_work->module);
 747         kfree(fw_work);
 748 }
 749
 750 /**
 751  * request_firmware_nowait - asynchronous version of request_firmware
 752  * @module: module requesting the firmware
 753  * @uevent: sends uevent to copy the firmware image if this flag
 754  *      is non-zero else the firmware copy must be done manually.
 755  * @name: name of firmware file
 756  * @device: device for which firmware is being loaded
 757  * @gfp: allocation flags
 758  * @context: will be passed over to @cont, and
 759  *      @fw may be %NULL if firmware request fails.
 760  * @cont: function will be called asynchronously when the firmware
 761  *      request is over.
 762  *
 763  *      Asynchronous variant of request_firmware() for user contexts where
 764  *      it is not possible to sleep for long time. It can't be called
 765  *      in atomic contexts.
 766  **/
 767 int
 768 request_firmware_nowait(
 769         struct module *module, bool uevent,
 770         const char *name, struct device *device, gfp_t gfp, void *context,
 771         void (*cont)(const struct firmware *fw, void *context))
 772 {
 773         struct firmware_work *fw_work;
 774
 775         fw_work = kzalloc(sizeof (struct firmware_work), gfp);
 776         if (!fw_work)
 777                 return -ENOMEM;
 778
 779         fw_work->module = module;
 780         fw_work->name = name;
 781         fw_work->device = device;
 782         fw_work->context = context;
 783         fw_work->cont = cont;
 784         fw_work->uevent = uevent;
 785
 786         if (!try_module_get(module)) {
 787                 kfree(fw_work);
 788                 return -EFAULT;
 789         }
 790
 791         INIT_WORK(&fw_work->work, request_firmware_work_func);
 792         schedule_work(&fw_work->work);
 793         return 0;
 794 }
 795
 796 static int __init firmware_class_init(void)
 797 {
 798         return class_register(&firmware_class);
 799 }
 800
 801 static void __exit firmware_class_exit(void)
 802 {
 803         class_unregister(&firmware_class);
 804 }
 805
 806 fs_initcall(firmware_class_init);
 807 module_exit(firmware_class_exit);
 808
 809 EXPORT_SYMBOL(release_firmware);
 810 EXPORT_SYMBOL(request_firmware);
 811 EXPORT_SYMBOL(request_firmware_nowait);