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         loff_t pos;
  64         long size;
  65         char *buf;
  66
  67         size = fw_file_size(file);
  68         if (size < 0)
  69                 return false;
  70         buf = vmalloc(size);
  71         if (!buf)
  72                 return false;
  73         pos = 0;
  74         if (vfs_read(file, buf, size, &pos) != size) {
  75                 vfree(buf);
  76                 return false;
  77         }
  78         fw->data = buf;
  79         fw->size = size;
  80         return true;
  81 }
  82
  83 static bool fw_get_filesystem_firmware(struct firmware *fw, const char *name)
  84 {
  85         int i;
  86         bool success = false;
  87         char *path = __getname();
  88
  89         for (i = 0; i < ARRAY_SIZE(fw_path); i++) {
  90                 struct file *file;
  91                 snprintf(path, PATH_MAX, "%s/%s", fw_path[i], name);
  92
  93                 file = filp_open(path, O_RDONLY, 0);
  94                 if (IS_ERR(file))
  95                         continue;
  96                 success = fw_read_file_contents(file, fw);
  97                 fput(file);
  98                 if (success)
  99                         break;
 100         }
 101         __putname(path);
 102         return success;
 103 }
 104
 105 /* Builtin firmware support */
 106
 107 #ifdef CONFIG_FW_LOADER
 108
 109 extern struct builtin_fw __start_builtin_fw[];
 110 extern struct builtin_fw __end_builtin_fw[];
 111
 112 static bool fw_get_builtin_firmware(struct firmware *fw, const char *name)
 113 {
 114         struct builtin_fw *b_fw;
 115
 116         for (b_fw = __start_builtin_fw; b_fw != __end_builtin_fw; b_fw++) {
 117                 if (strcmp(name, b_fw->name) == 0) {
 118                         fw->size = b_fw->size;
 119                         fw->data = b_fw->data;
 120                         return true;
 121                 }
 122         }
 123
 124         return false;
 125 }
 126
 127 static bool fw_is_builtin_firmware(const struct firmware *fw)
 128 {
 129         struct builtin_fw *b_fw;
 130
 131         for (b_fw = __start_builtin_fw; b_fw != __end_builtin_fw; b_fw++)
 132                 if (fw->data == b_fw->data)
 133                         return true;
 134
 135         return false;
 136 }
 137
 138 #else /* Module case - no builtin firmware support */
 139
 140 static inline bool fw_get_builtin_firmware(struct firmware *fw, const char *name)
 141 {
 142         return false;
 143 }
 144
 145 static inline bool fw_is_builtin_firmware(const struct firmware *fw)
 146 {
 147         return false;
 148 }
 149 #endif
 150
 151 enum {
 152         FW_STATUS_LOADING,
 153         FW_STATUS_DONE,
 154         FW_STATUS_ABORT,
 155 };
 156
 157 static int loading_timeout = 60;        /* In seconds */
 158
 159 static inline long firmware_loading_timeout(void)
 160 {
 161         return loading_timeout > 0 ? loading_timeout * HZ : MAX_SCHEDULE_TIMEOUT;
 162 }
 163
 164 /* fw_lock could be moved to 'struct firmware_priv' but since it is just
 165  * guarding for corner cases a global lock should be OK */
 166 static DEFINE_MUTEX(fw_lock);
 167
 168 struct firmware_priv {
 169         struct completion completion;
 170         struct firmware *fw;
 171         unsigned long status;
 172         struct page **pages;
 173         int nr_pages;
 174         int page_array_size;
 175         struct timer_list timeout;
 176         struct device dev;
 177         bool nowait;
 178         char fw_id[];
 179 };
 180
 181 static struct firmware_priv *to_firmware_priv(struct device *dev)
 182 {
 183         return container_of(dev, struct firmware_priv, dev);
 184 }
 185
 186 static void fw_load_abort(struct firmware_priv *fw_priv)
 187 {
 188         set_bit(FW_STATUS_ABORT, &fw_priv->status);
 189         wmb();
 190         complete(&fw_priv->completion);
 191 }
 192
 193 static ssize_t firmware_timeout_show(struct class *class,
 194                                      struct class_attribute *attr,
 195                                      char *buf)
 196 {
 197         return sprintf(buf, "%d\n", loading_timeout);
 198 }
 199
 200 /**
 201  * firmware_timeout_store - set number of seconds to wait for firmware
 202  * @class: device class pointer
 203  * @attr: device attribute pointer
 204  * @buf: buffer to scan for timeout value
 205  * @count: number of bytes in @buf
 206  *
 207  *      Sets the number of seconds to wait for the firmware.  Once
 208  *      this expires an error will be returned to the driver and no
 209  *      firmware will be provided.
 210  *
 211  *      Note: zero means 'wait forever'.
 212  **/
 213 static ssize_t firmware_timeout_store(struct class *class,
 214                                       struct class_attribute *attr,
 215                                       const char *buf, size_t count)
 216 {
 217         loading_timeout = simple_strtol(buf, NULL, 10);
 218         if (loading_timeout < 0)
 219                 loading_timeout = 0;
 220
 221         return count;
 222 }
 223
 224 static struct class_attribute firmware_class_attrs[] = {
 225         __ATTR(timeout, S_IWUSR | S_IRUGO,
 226                 firmware_timeout_show, firmware_timeout_store),
 227         __ATTR_NULL
 228 };
 229
 230 static void fw_dev_release(struct device *dev)
 231 {
 232         struct firmware_priv *fw_priv = to_firmware_priv(dev);
 233         int i;
 234
 235         for (i = 0; i < fw_priv->nr_pages; i++)
 236                 __free_page(fw_priv->pages[i]);
 237         kfree(fw_priv->pages);
 238         kfree(fw_priv);
 239
 240         module_put(THIS_MODULE);
 241 }
 242
 243 static int firmware_uevent(struct device *dev, struct kobj_uevent_env *env)
 244 {
 245         struct firmware_priv *fw_priv = to_firmware_priv(dev);
 246
 247         if (add_uevent_var(env, "FIRMWARE=%s", fw_priv->fw_id))
 248                 return -ENOMEM;
 249         if (add_uevent_var(env, "TIMEOUT=%i", loading_timeout))
 250                 return -ENOMEM;
 251         if (add_uevent_var(env, "ASYNC=%d", fw_priv->nowait))
 252                 return -ENOMEM;
 253
 254         return 0;
 255 }
 256
 257 static struct class firmware_class = {
 258         .name           = "firmware",
 259         .class_attrs    = firmware_class_attrs,
 260         .dev_uevent     = firmware_uevent,
 261         .dev_release    = fw_dev_release,
 262 };
 263
 264 static ssize_t firmware_loading_show(struct device *dev,
 265                                      struct device_attribute *attr, char *buf)
 266 {
 267         struct firmware_priv *fw_priv = to_firmware_priv(dev);
 268         int loading = test_bit(FW_STATUS_LOADING, &fw_priv->status);
 269
 270         return sprintf(buf, "%d\n", loading);
 271 }
 272
 273 static void firmware_free_data(const struct firmware *fw)
 274 {
 275         int i;
 276         /* Loaded directly? */
 277         if (!fw->priv) {
 278                 vfree(fw->data);
 279                 return;
 280         }
 281         vunmap(fw->data);
 282         if (fw->pages) {
 283                 for (i = 0; i < PFN_UP(fw->size); i++)
 284                         __free_page(fw->pages[i]);
 285                 kfree(fw->pages);
 286         }
 287 }
 288
 289 /* Some architectures don't have PAGE_KERNEL_RO */
 290 #ifndef PAGE_KERNEL_RO
 291 #define PAGE_KERNEL_RO PAGE_KERNEL
 292 #endif
 293 /**
 294  * firmware_loading_store - set value in the 'loading' control file
 295  * @dev: device pointer
 296  * @attr: device attribute pointer
 297  * @buf: buffer to scan for loading control value
 298  * @count: number of bytes in @buf
 299  *
 300  *      The relevant values are:
 301  *
 302  *       1: Start a load, discarding any previous partial load.
 303  *       0: Conclude the load and hand the data to the driver code.
 304  *      -1: Conclude the load with an error and discard any written data.
 305  **/
 306 static ssize_t firmware_loading_store(struct device *dev,
 307                                       struct device_attribute *attr,
 308                                       const char *buf, size_t count)
 309 {
 310         struct firmware_priv *fw_priv = to_firmware_priv(dev);
 311         int loading = simple_strtol(buf, NULL, 10);
 312         int i;
 313
 314         mutex_lock(&fw_lock);
 315
 316         if (!fw_priv->fw)
 317                 goto out;
 318
 319         switch (loading) {
 320         case 1:
 321                 firmware_free_data(fw_priv->fw);
 322                 memset(fw_priv->fw, 0, sizeof(struct firmware));
 323                 /* If the pages are not owned by 'struct firmware' */
 324                 for (i = 0; i < fw_priv->nr_pages; i++)
 325                         __free_page(fw_priv->pages[i]);
 326                 kfree(fw_priv->pages);
 327                 fw_priv->pages = NULL;
 328                 fw_priv->page_array_size = 0;
 329                 fw_priv->nr_pages = 0;
 330                 set_bit(FW_STATUS_LOADING, &fw_priv->status);
 331                 break;
 332         case 0:
 333                 if (test_bit(FW_STATUS_LOADING, &fw_priv->status)) {
 334                         vunmap(fw_priv->fw->data);
 335                         fw_priv->fw->data = vmap(fw_priv->pages,
 336                                                  fw_priv->nr_pages,
 337                                                  0, PAGE_KERNEL_RO);
 338                         if (!fw_priv->fw->data) {
 339                                 dev_err(dev, "%s: vmap() failed\n", __func__);
 340                                 goto err;
 341                         }
 342                         /* Pages are now owned by 'struct firmware' */
 343                         fw_priv->fw->pages = fw_priv->pages;
 344                         fw_priv->pages = NULL;
 345
 346                         fw_priv->page_array_size = 0;
 347                         fw_priv->nr_pages = 0;
 348                         complete(&fw_priv->completion);
 349                         clear_bit(FW_STATUS_LOADING, &fw_priv->status);
 350                         break;
 351                 }
 352                 /* fallthrough */
 353         default:
 354                 dev_err(dev, "%s: unexpected value (%d)\n", __func__, loading);
 355                 /* fallthrough */
 356         case -1:
 357         err:
 358                 fw_load_abort(fw_priv);
 359                 break;
 360         }
 361 out:
 362         mutex_unlock(&fw_lock);
 363         return count;
 364 }
 365
 366 static DEVICE_ATTR(loading, 0644, firmware_loading_show, firmware_loading_store);
 367
 368 static ssize_t firmware_data_read(struct file *filp, struct kobject *kobj,
 369                                   struct bin_attribute *bin_attr,
 370                                   char *buffer, loff_t offset, size_t count)
 371 {
 372         struct device *dev = to_dev(kobj);
 373         struct firmware_priv *fw_priv = to_firmware_priv(dev);
 374         struct firmware *fw;
 375         ssize_t ret_count;
 376
 377         mutex_lock(&fw_lock);
 378         fw = fw_priv->fw;
 379         if (!fw || test_bit(FW_STATUS_DONE, &fw_priv->status)) {
 380                 ret_count = -ENODEV;
 381                 goto out;
 382         }
 383         if (offset > fw->size) {
 384                 ret_count = 0;
 385                 goto out;
 386         }
 387         if (count > fw->size - offset)
 388                 count = fw->size - offset;
 389
 390         ret_count = count;
 391
 392         while (count) {
 393                 void *page_data;
 394                 int page_nr = offset >> PAGE_SHIFT;
 395                 int page_ofs = offset & (PAGE_SIZE-1);
 396                 int page_cnt = min_t(size_t, PAGE_SIZE - page_ofs, count);
 397
 398                 page_data = kmap(fw_priv->pages[page_nr]);
 399
 400                 memcpy(buffer, page_data + page_ofs, page_cnt);
 401
 402                 kunmap(fw_priv->pages[page_nr]);
 403                 buffer += page_cnt;
 404                 offset += page_cnt;
 405                 count -= page_cnt;
 406         }
 407 out:
 408         mutex_unlock(&fw_lock);
 409         return ret_count;
 410 }
 411
 412 static int fw_realloc_buffer(struct firmware_priv *fw_priv, int min_size)
 413 {
 414         int pages_needed = ALIGN(min_size, PAGE_SIZE) >> PAGE_SHIFT;
 415
 416         /* If the array of pages is too small, grow it... */
 417         if (fw_priv->page_array_size < pages_needed) {
 418                 int new_array_size = max(pages_needed,
 419                                          fw_priv->page_array_size * 2);
 420                 struct page **new_pages;
 421
 422                 new_pages = kmalloc(new_array_size * sizeof(void *),
 423                                     GFP_KERNEL);
 424                 if (!new_pages) {
 425                         fw_load_abort(fw_priv);
 426                         return -ENOMEM;
 427                 }
 428                 memcpy(new_pages, fw_priv->pages,
 429                        fw_priv->page_array_size * sizeof(void *));
 430                 memset(&new_pages[fw_priv->page_array_size], 0, sizeof(void *) *
 431                        (new_array_size - fw_priv->page_array_size));
 432                 kfree(fw_priv->pages);
 433                 fw_priv->pages = new_pages;
 434                 fw_priv->page_array_size = new_array_size;
 435         }
 436
 437         while (fw_priv->nr_pages < pages_needed) {
 438                 fw_priv->pages[fw_priv->nr_pages] =
 439                         alloc_page(GFP_KERNEL | __GFP_HIGHMEM);
 440
 441                 if (!fw_priv->pages[fw_priv->nr_pages]) {
 442                         fw_load_abort(fw_priv);
 443                         return -ENOMEM;
 444                 }
 445                 fw_priv->nr_pages++;
 446         }
 447         return 0;
 448 }
 449
 450 /**
 451  * firmware_data_write - write method for firmware
 452  * @filp: open sysfs file
 453  * @kobj: kobject for the device
 454  * @bin_attr: bin_attr structure
 455  * @buffer: buffer being written
 456  * @offset: buffer offset for write in total data store area
 457  * @count: buffer size
 458  *
 459  *      Data written to the 'data' attribute will be later handed to
 460  *      the driver as a firmware image.
 461  **/
 462 static ssize_t firmware_data_write(struct file *filp, struct kobject *kobj,
 463                                    struct bin_attribute *bin_attr,
 464                                    char *buffer, loff_t offset, size_t count)
 465 {
 466         struct device *dev = to_dev(kobj);
 467         struct firmware_priv *fw_priv = to_firmware_priv(dev);
 468         struct firmware *fw;
 469         ssize_t retval;
 470
 471         if (!capable(CAP_SYS_RAWIO))
 472                 return -EPERM;
 473
 474         mutex_lock(&fw_lock);
 475         fw = fw_priv->fw;
 476         if (!fw || test_bit(FW_STATUS_DONE, &fw_priv->status)) {
 477                 retval = -ENODEV;
 478                 goto out;
 479         }
 480         retval = fw_realloc_buffer(fw_priv, offset + count);
 481         if (retval)
 482                 goto out;
 483
 484         retval = count;
 485
 486         while (count) {
 487                 void *page_data;
 488                 int page_nr = offset >> PAGE_SHIFT;
 489                 int page_ofs = offset & (PAGE_SIZE - 1);
 490                 int page_cnt = min_t(size_t, PAGE_SIZE - page_ofs, count);
 491
 492                 page_data = kmap(fw_priv->pages[page_nr]);
 493
 494                 memcpy(page_data + page_ofs, buffer, page_cnt);
 495
 496                 kunmap(fw_priv->pages[page_nr]);
 497                 buffer += page_cnt;
 498                 offset += page_cnt;
 499                 count -= page_cnt;
 500         }
 501
 502         fw->size = max_t(size_t, offset, fw->size);
 503 out:
 504         mutex_unlock(&fw_lock);
 505         return retval;
 506 }
 507
 508 static struct bin_attribute firmware_attr_data = {
 509         .attr = { .name = "data", .mode = 0644 },
 510         .size = 0,
 511         .read = firmware_data_read,
 512         .write = firmware_data_write,
 513 };
 514
 515 static void firmware_class_timeout(u_long data)
 516 {
 517         struct firmware_priv *fw_priv = (struct firmware_priv *) data;
 518
 519         fw_load_abort(fw_priv);
 520 }
 521
 522 static struct firmware_priv *
 523 fw_create_instance(struct firmware *firmware, const char *fw_name,
 524                    struct device *device, bool uevent, bool nowait)
 525 {
 526         struct firmware_priv *fw_priv;
 527         struct device *f_dev;
 528
 529         fw_priv = kzalloc(sizeof(*fw_priv) + strlen(fw_name) + 1 , GFP_KERNEL);
 530         if (!fw_priv) {
 531                 dev_err(device, "%s: kmalloc failed\n", __func__);
 532                 return ERR_PTR(-ENOMEM);
 533         }
 534
 535         fw_priv->fw = firmware;
 536         fw_priv->nowait = nowait;
 537         strcpy(fw_priv->fw_id, fw_name);
 538         init_completion(&fw_priv->completion);
 539         setup_timer(&fw_priv->timeout,
 540                     firmware_class_timeout, (u_long) fw_priv);
 541
 542         f_dev = &fw_priv->dev;
 543
 544         device_initialize(f_dev);
 545         dev_set_name(f_dev, "%s", dev_name(device));
 546         f_dev->parent = device;
 547         f_dev->class = &firmware_class;
 548
 549         return fw_priv;
 550 }
 551
 552 static struct firmware_priv *
 553 _request_firmware_prepare(const struct firmware **firmware_p, const char *name,
 554                           struct device *device, bool uevent, bool nowait)
 555 {
 556         struct firmware *firmware;
 557         struct firmware_priv *fw_priv;
 558
 559         if (!firmware_p)
 560                 return ERR_PTR(-EINVAL);
 561
 562         *firmware_p = firmware = kzalloc(sizeof(*firmware), GFP_KERNEL);
 563         if (!firmware) {
 564                 dev_err(device, "%s: kmalloc(struct firmware) failed\n",
 565                         __func__);
 566                 return ERR_PTR(-ENOMEM);
 567         }
 568
 569         if (fw_get_builtin_firmware(firmware, name)) {
 570                 dev_dbg(device, "firmware: using built-in firmware %s\n", name);
 571                 return NULL;
 572         }
 573
 574         if (fw_get_filesystem_firmware(firmware, name)) {
 575                 dev_dbg(device, "firmware: direct-loading firmware %s\n", name);
 576                 return NULL;
 577         }
 578
 579         fw_priv = fw_create_instance(firmware, name, device, uevent, nowait);
 580         if (IS_ERR(fw_priv)) {
 581                 release_firmware(firmware);
 582                 *firmware_p = NULL;
 583         }
 584         return fw_priv;
 585 }
 586
 587 static void _request_firmware_cleanup(const struct firmware **firmware_p)
 588 {
 589         release_firmware(*firmware_p);
 590         *firmware_p = NULL;
 591 }
 592
 593 static int _request_firmware_load(struct firmware_priv *fw_priv, bool uevent,
 594                                   long timeout)
 595 {
 596         int retval = 0;
 597         struct device *f_dev = &fw_priv->dev;
 598
 599         dev_set_uevent_suppress(f_dev, true);
 600
 601         /* Need to pin this module until class device is destroyed */
 602         __module_get(THIS_MODULE);
 603
 604         retval = device_add(f_dev);
 605         if (retval) {
 606                 dev_err(f_dev, "%s: device_register failed\n", __func__);
 607                 goto err_put_dev;
 608         }
 609
 610         retval = device_create_bin_file(f_dev, &firmware_attr_data);
 611         if (retval) {
 612                 dev_err(f_dev, "%s: sysfs_create_bin_file failed\n", __func__);
 613                 goto err_del_dev;
 614         }
 615
 616         retval = device_create_file(f_dev, &dev_attr_loading);
 617         if (retval) {
 618                 dev_err(f_dev, "%s: device_create_file failed\n", __func__);
 619                 goto err_del_bin_attr;
 620         }
 621
 622         if (uevent) {
 623                 dev_set_uevent_suppress(f_dev, false);
 624                 dev_dbg(f_dev, "firmware: requesting %s\n", fw_priv->fw_id);
 625                 if (timeout != MAX_SCHEDULE_TIMEOUT)
 626                         mod_timer(&fw_priv->timeout,
 627                                   round_jiffies_up(jiffies + timeout));
 628
 629                 kobject_uevent(&fw_priv->dev.kobj, KOBJ_ADD);
 630         }
 631
 632         wait_for_completion(&fw_priv->completion);
 633
 634         set_bit(FW_STATUS_DONE, &fw_priv->status);
 635         del_timer_sync(&fw_priv->timeout);
 636
 637         mutex_lock(&fw_lock);
 638         if (!fw_priv->fw->size || test_bit(FW_STATUS_ABORT, &fw_priv->status))
 639                 retval = -ENOENT;
 640         fw_priv->fw = NULL;
 641         mutex_unlock(&fw_lock);
 642
 643         device_remove_file(f_dev, &dev_attr_loading);
 644 err_del_bin_attr:
 645         device_remove_bin_file(f_dev, &firmware_attr_data);
 646 err_del_dev:
 647         device_del(f_dev);
 648 err_put_dev:
 649         put_device(f_dev);
 650         return retval;
 651 }
 652
 653 /**
 654  * request_firmware: - send firmware request and wait for it
 655  * @firmware_p: pointer to firmware image
 656  * @name: name of firmware file
 657  * @device: device for which firmware is being loaded
 658  *
 659  *      @firmware_p will be used to return a firmware image by the name
 660  *      of @name for device @device.
 661  *
 662  *      Should be called from user context where sleeping is allowed.
 663  *
 664  *      @name will be used as $FIRMWARE in the uevent environment and
 665  *      should be distinctive enough not to be confused with any other
 666  *      firmware image for this or any other device.
 667  **/
 668 int
 669 request_firmware(const struct firmware **firmware_p, const char *name,
 670                  struct device *device)
 671 {
 672         struct firmware_priv *fw_priv;
 673         int ret;
 674
 675         fw_priv = _request_firmware_prepare(firmware_p, name, device, true,
 676                                             false);
 677         if (IS_ERR_OR_NULL(fw_priv))
 678                 return PTR_RET(fw_priv);
 679
 680         ret = usermodehelper_read_trylock();
 681         if (ret) {
 682                 kfree(fw_priv);
 683                 dev_err(device, "firmware: %s will not be loaded\n", name);
 684         } else {
 685                 ret = _request_firmware_load(fw_priv, true,
 686                                         firmware_loading_timeout());
 687                 usermodehelper_read_unlock();
 688         }
 689         if (ret)
 690                 _request_firmware_cleanup(firmware_p);
 691
 692         return ret;
 693 }
 694
 695 /**
 696  * release_firmware: - release the resource associated with a firmware image
 697  * @fw: firmware resource to release
 698  **/
 699 void release_firmware(const struct firmware *fw)
 700 {
 701         if (fw) {
 702                 if (!fw_is_builtin_firmware(fw))
 703                         firmware_free_data(fw);
 704                 kfree(fw);
 705         }
 706 }
 707
 708 /* Async support */
 709 struct firmware_work {
 710         struct work_struct work;
 711         struct module *module;
 712         const char *name;
 713         struct device *device;
 714         void *context;
 715         void (*cont)(const struct firmware *fw, void *context);
 716         bool uevent;
 717 };
 718
 719 static void request_firmware_work_func(struct work_struct *work)
 720 {
 721         struct firmware_work *fw_work;
 722         const struct firmware *fw;
 723         struct firmware_priv *fw_priv;
 724         long timeout;
 725         int ret;
 726
 727         fw_work = container_of(work, struct firmware_work, work);
 728         fw_priv = _request_firmware_prepare(&fw, fw_work->name, fw_work->device,
 729                         fw_work->uevent, true);
 730         if (IS_ERR_OR_NULL(fw_priv)) {
 731                 ret = PTR_RET(fw_priv);
 732                 goto out;
 733         }
 734
 735         timeout = usermodehelper_read_lock_wait(firmware_loading_timeout());
 736         if (timeout) {
 737                 ret = _request_firmware_load(fw_priv, fw_work->uevent, timeout);
 738                 usermodehelper_read_unlock();
 739         } else {
 740                 dev_dbg(fw_work->device, "firmware: %s loading timed out\n",
 741                         fw_work->name);
 742                 ret = -EAGAIN;
 743         }
 744         if (ret)
 745                 _request_firmware_cleanup(&fw);
 746
 747  out:
 748         fw_work->cont(fw, fw_work->context);
 749
 750         module_put(fw_work->module);
 751         kfree(fw_work);
 752 }
 753
 754 /**
 755  * request_firmware_nowait - asynchronous version of request_firmware
 756  * @module: module requesting the firmware
 757  * @uevent: sends uevent to copy the firmware image if this flag
 758  *      is non-zero else the firmware copy must be done manually.
 759  * @name: name of firmware file
 760  * @device: device for which firmware is being loaded
 761  * @gfp: allocation flags
 762  * @context: will be passed over to @cont, and
 763  *      @fw may be %NULL if firmware request fails.
 764  * @cont: function will be called asynchronously when the firmware
 765  *      request is over.
 766  *
 767  *      Asynchronous variant of request_firmware() for user contexts where
 768  *      it is not possible to sleep for long time. It can't be called
 769  *      in atomic contexts.
 770  **/
 771 int
 772 request_firmware_nowait(
 773         struct module *module, bool uevent,
 774         const char *name, struct device *device, gfp_t gfp, void *context,
 775         void (*cont)(const struct firmware *fw, void *context))
 776 {
 777         struct firmware_work *fw_work;
 778
 779         fw_work = kzalloc(sizeof (struct firmware_work), gfp);
 780         if (!fw_work)
 781                 return -ENOMEM;
 782
 783         fw_work->module = module;
 784         fw_work->name = name;
 785         fw_work->device = device;
 786         fw_work->context = context;
 787         fw_work->cont = cont;
 788         fw_work->uevent = uevent;
 789
 790         if (!try_module_get(module)) {
 791                 kfree(fw_work);
 792                 return -EFAULT;
 793         }
 794
 795         INIT_WORK(&fw_work->work, request_firmware_work_func);
 796         schedule_work(&fw_work->work);
 797         return 0;
 798 }
 799
 800 static int __init firmware_class_init(void)
 801 {
 802         return class_register(&firmware_class);
 803 }
 804
 805 static void __exit firmware_class_exit(void)
 806 {
 807         class_unregister(&firmware_class);
 808 }
 809
 810 fs_initcall(firmware_class_init);
 811 module_exit(firmware_class_exit);
 812
 813 EXPORT_SYMBOL(release_firmware);
 814 EXPORT_SYMBOL(request_firmware);
 815 EXPORT_SYMBOL(request_firmware_nowait);