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         /* Loaded directly? */
 275         if (!fw->priv) {
 276                 vfree(fw->data);
 277                 return;
 278         }
 279         vunmap(fw->data);
 280         if (fw->pages) {
 281                 for (i = 0; i < PFN_UP(fw->size); i++)
 282                         __free_page(fw->pages[i]);
 283                 kfree(fw->pages);
 284         }
 285 }
 286
 287 /* Some architectures don't have PAGE_KERNEL_RO */
 288 #ifndef PAGE_KERNEL_RO
 289 #define PAGE_KERNEL_RO PAGE_KERNEL
 290 #endif
 291 /**
 292  * firmware_loading_store - set value in the 'loading' control file
 293  * @dev: device pointer
 294  * @attr: device attribute pointer
 295  * @buf: buffer to scan for loading control value
 296  * @count: number of bytes in @buf
 297  *
 298  *      The relevant values are:
 299  *
 300  *       1: Start a load, discarding any previous partial load.
 301  *       0: Conclude the load and hand the data to the driver code.
 302  *      -1: Conclude the load with an error and discard any written data.
 303  **/
 304 static ssize_t firmware_loading_store(struct device *dev,
 305                                       struct device_attribute *attr,
 306                                       const char *buf, size_t count)
 307 {
 308         struct firmware_priv *fw_priv = to_firmware_priv(dev);
 309         int loading = simple_strtol(buf, NULL, 10);
 310         int i;
 311
 312         mutex_lock(&fw_lock);
 313
 314         if (!fw_priv->fw)
 315                 goto out;
 316
 317         switch (loading) {
 318         case 1:
 319                 firmware_free_data(fw_priv->fw);
 320                 memset(fw_priv->fw, 0, sizeof(struct firmware));
 321                 /* If the pages are not owned by 'struct firmware' */
 322                 for (i = 0; i < fw_priv->nr_pages; i++)
 323                         __free_page(fw_priv->pages[i]);
 324                 kfree(fw_priv->pages);
 325                 fw_priv->pages = NULL;
 326                 fw_priv->page_array_size = 0;
 327                 fw_priv->nr_pages = 0;
 328                 set_bit(FW_STATUS_LOADING, &fw_priv->status);
 329                 break;
 330         case 0:
 331                 if (test_bit(FW_STATUS_LOADING, &fw_priv->status)) {
 332                         vunmap(fw_priv->fw->data);
 333                         fw_priv->fw->data = vmap(fw_priv->pages,
 334                                                  fw_priv->nr_pages,
 335                                                  0, PAGE_KERNEL_RO);
 336                         if (!fw_priv->fw->data) {
 337                                 dev_err(dev, "%s: vmap() failed\n", __func__);
 338                                 goto err;
 339                         }
 340                         /* Pages are now owned by 'struct firmware' */
 341                         fw_priv->fw->pages = fw_priv->pages;
 342                         fw_priv->pages = NULL;
 343
 344                         fw_priv->page_array_size = 0;
 345                         fw_priv->nr_pages = 0;
 346                         complete(&fw_priv->completion);
 347                         clear_bit(FW_STATUS_LOADING, &fw_priv->status);
 348                         break;
 349                 }
 350                 /* fallthrough */
 351         default:
 352                 dev_err(dev, "%s: unexpected value (%d)\n", __func__, loading);
 353                 /* fallthrough */
 354         case -1:
 355         err:
 356                 fw_load_abort(fw_priv);
 357                 break;
 358         }
 359 out:
 360         mutex_unlock(&fw_lock);
 361         return count;
 362 }
 363
 364 static DEVICE_ATTR(loading, 0644, firmware_loading_show, firmware_loading_store);
 365
 366 static ssize_t firmware_data_read(struct file *filp, struct kobject *kobj,
 367                                   struct bin_attribute *bin_attr,
 368                                   char *buffer, loff_t offset, size_t count)
 369 {
 370         struct device *dev = to_dev(kobj);
 371         struct firmware_priv *fw_priv = to_firmware_priv(dev);
 372         struct firmware *fw;
 373         ssize_t ret_count;
 374
 375         mutex_lock(&fw_lock);
 376         fw = fw_priv->fw;
 377         if (!fw || test_bit(FW_STATUS_DONE, &fw_priv->status)) {
 378                 ret_count = -ENODEV;
 379                 goto out;
 380         }
 381         if (offset > fw->size) {
 382                 ret_count = 0;
 383                 goto out;
 384         }
 385         if (count > fw->size - offset)
 386                 count = fw->size - offset;
 387
 388         ret_count = count;
 389
 390         while (count) {
 391                 void *page_data;
 392                 int page_nr = offset >> PAGE_SHIFT;
 393                 int page_ofs = offset & (PAGE_SIZE-1);
 394                 int page_cnt = min_t(size_t, PAGE_SIZE - page_ofs, count);
 395
 396                 page_data = kmap(fw_priv->pages[page_nr]);
 397
 398                 memcpy(buffer, page_data + page_ofs, page_cnt);
 399
 400                 kunmap(fw_priv->pages[page_nr]);
 401                 buffer += page_cnt;
 402                 offset += page_cnt;
 403                 count -= page_cnt;
 404         }
 405 out:
 406         mutex_unlock(&fw_lock);
 407         return ret_count;
 408 }
 409
 410 static int fw_realloc_buffer(struct firmware_priv *fw_priv, int min_size)
 411 {
 412         int pages_needed = ALIGN(min_size, PAGE_SIZE) >> PAGE_SHIFT;
 413
 414         /* If the array of pages is too small, grow it... */
 415         if (fw_priv->page_array_size < pages_needed) {
 416                 int new_array_size = max(pages_needed,
 417                                          fw_priv->page_array_size * 2);
 418                 struct page **new_pages;
 419
 420                 new_pages = kmalloc(new_array_size * sizeof(void *),
 421                                     GFP_KERNEL);
 422                 if (!new_pages) {
 423                         fw_load_abort(fw_priv);
 424                         return -ENOMEM;
 425                 }
 426                 memcpy(new_pages, fw_priv->pages,
 427                        fw_priv->page_array_size * sizeof(void *));
 428                 memset(&new_pages[fw_priv->page_array_size], 0, sizeof(void *) *
 429                        (new_array_size - fw_priv->page_array_size));
 430                 kfree(fw_priv->pages);
 431                 fw_priv->pages = new_pages;
 432                 fw_priv->page_array_size = new_array_size;
 433         }
 434
 435         while (fw_priv->nr_pages < pages_needed) {
 436                 fw_priv->pages[fw_priv->nr_pages] =
 437                         alloc_page(GFP_KERNEL | __GFP_HIGHMEM);
 438
 439                 if (!fw_priv->pages[fw_priv->nr_pages]) {
 440                         fw_load_abort(fw_priv);
 441                         return -ENOMEM;
 442                 }
 443                 fw_priv->nr_pages++;
 444         }
 445         return 0;
 446 }
 447
 448 /**
 449  * firmware_data_write - write method for firmware
 450  * @filp: open sysfs file
 451  * @kobj: kobject for the device
 452  * @bin_attr: bin_attr structure
 453  * @buffer: buffer being written
 454  * @offset: buffer offset for write in total data store area
 455  * @count: buffer size
 456  *
 457  *      Data written to the 'data' attribute will be later handed to
 458  *      the driver as a firmware image.
 459  **/
 460 static ssize_t firmware_data_write(struct file *filp, struct kobject *kobj,
 461                                    struct bin_attribute *bin_attr,
 462                                    char *buffer, loff_t offset, size_t count)
 463 {
 464         struct device *dev = to_dev(kobj);
 465         struct firmware_priv *fw_priv = to_firmware_priv(dev);
 466         struct firmware *fw;
 467         ssize_t retval;
 468
 469         if (!capable(CAP_SYS_RAWIO))
 470                 return -EPERM;
 471
 472         mutex_lock(&fw_lock);
 473         fw = fw_priv->fw;
 474         if (!fw || test_bit(FW_STATUS_DONE, &fw_priv->status)) {
 475                 retval = -ENODEV;
 476                 goto out;
 477         }
 478         retval = fw_realloc_buffer(fw_priv, offset + count);
 479         if (retval)
 480                 goto out;
 481
 482         retval = count;
 483
 484         while (count) {
 485                 void *page_data;
 486                 int page_nr = offset >> PAGE_SHIFT;
 487                 int page_ofs = offset & (PAGE_SIZE - 1);
 488                 int page_cnt = min_t(size_t, PAGE_SIZE - page_ofs, count);
 489
 490                 page_data = kmap(fw_priv->pages[page_nr]);
 491
 492                 memcpy(page_data + page_ofs, buffer, page_cnt);
 493
 494                 kunmap(fw_priv->pages[page_nr]);
 495                 buffer += page_cnt;
 496                 offset += page_cnt;
 497                 count -= page_cnt;
 498         }
 499
 500         fw->size = max_t(size_t, offset, fw->size);
 501 out:
 502         mutex_unlock(&fw_lock);
 503         return retval;
 504 }
 505
 506 static struct bin_attribute firmware_attr_data = {
 507         .attr = { .name = "data", .mode = 0644 },
 508         .size = 0,
 509         .read = firmware_data_read,
 510         .write = firmware_data_write,
 511 };
 512
 513 static void firmware_class_timeout(u_long data)
 514 {
 515         struct firmware_priv *fw_priv = (struct firmware_priv *) data;
 516
 517         fw_load_abort(fw_priv);
 518 }
 519
 520 static struct firmware_priv *
 521 fw_create_instance(struct firmware *firmware, const char *fw_name,
 522                    struct device *device, bool uevent, bool nowait)
 523 {
 524         struct firmware_priv *fw_priv;
 525         struct device *f_dev;
 526
 527         fw_priv = kzalloc(sizeof(*fw_priv) + strlen(fw_name) + 1 , GFP_KERNEL);
 528         if (!fw_priv) {
 529                 dev_err(device, "%s: kmalloc failed\n", __func__);
 530                 return ERR_PTR(-ENOMEM);
 531         }
 532
 533         fw_priv->fw = firmware;
 534         fw_priv->nowait = nowait;
 535         strcpy(fw_priv->fw_id, fw_name);
 536         init_completion(&fw_priv->completion);
 537         setup_timer(&fw_priv->timeout,
 538                     firmware_class_timeout, (u_long) fw_priv);
 539
 540         f_dev = &fw_priv->dev;
 541
 542         device_initialize(f_dev);
 543         dev_set_name(f_dev, "%s", dev_name(device));
 544         f_dev->parent = device;
 545         f_dev->class = &firmware_class;
 546
 547         return fw_priv;
 548 }
 549
 550 static struct firmware_priv *
 551 _request_firmware_prepare(const struct firmware **firmware_p, const char *name,
 552                           struct device *device, bool uevent, bool nowait)
 553 {
 554         struct firmware *firmware;
 555         struct firmware_priv *fw_priv;
 556
 557         if (!firmware_p)
 558                 return ERR_PTR(-EINVAL);
 559
 560         *firmware_p = firmware = kzalloc(sizeof(*firmware), GFP_KERNEL);
 561         if (!firmware) {
 562                 dev_err(device, "%s: kmalloc(struct firmware) failed\n",
 563                         __func__);
 564                 return ERR_PTR(-ENOMEM);
 565         }
 566
 567         if (fw_get_builtin_firmware(firmware, name)) {
 568                 dev_dbg(device, "firmware: using built-in firmware %s\n", name);
 569                 return NULL;
 570         }
 571
 572         if (fw_get_filesystem_firmware(firmware, name)) {
 573                 dev_dbg(device, "firmware: direct-loading firmware %s\n", name);
 574                 return NULL;
 575         }
 576
 577         fw_priv = fw_create_instance(firmware, name, device, uevent, nowait);
 578         if (IS_ERR(fw_priv)) {
 579                 release_firmware(firmware);
 580                 *firmware_p = NULL;
 581         }
 582         return fw_priv;
 583 }
 584
 585 static void _request_firmware_cleanup(const struct firmware **firmware_p)
 586 {
 587         release_firmware(*firmware_p);
 588         *firmware_p = NULL;
 589 }
 590
 591 static int _request_firmware_load(struct firmware_priv *fw_priv, bool uevent,
 592                                   long timeout)
 593 {
 594         int retval = 0;
 595         struct device *f_dev = &fw_priv->dev;
 596
 597         dev_set_uevent_suppress(f_dev, true);
 598
 599         /* Need to pin this module until class device is destroyed */
 600         __module_get(THIS_MODULE);
 601
 602         retval = device_add(f_dev);
 603         if (retval) {
 604                 dev_err(f_dev, "%s: device_register failed\n", __func__);
 605                 goto err_put_dev;
 606         }
 607
 608         retval = device_create_bin_file(f_dev, &firmware_attr_data);
 609         if (retval) {
 610                 dev_err(f_dev, "%s: sysfs_create_bin_file failed\n", __func__);
 611                 goto err_del_dev;
 612         }
 613
 614         retval = device_create_file(f_dev, &dev_attr_loading);
 615         if (retval) {
 616                 dev_err(f_dev, "%s: device_create_file failed\n", __func__);
 617                 goto err_del_bin_attr;
 618         }
 619
 620         if (uevent) {
 621                 dev_set_uevent_suppress(f_dev, false);
 622                 dev_dbg(f_dev, "firmware: requesting %s\n", fw_priv->fw_id);
 623                 if (timeout != MAX_SCHEDULE_TIMEOUT)
 624                         mod_timer(&fw_priv->timeout,
 625                                   round_jiffies_up(jiffies + timeout));
 626
 627                 kobject_uevent(&fw_priv->dev.kobj, KOBJ_ADD);
 628         }
 629
 630         wait_for_completion(&fw_priv->completion);
 631
 632         set_bit(FW_STATUS_DONE, &fw_priv->status);
 633         del_timer_sync(&fw_priv->timeout);
 634
 635         mutex_lock(&fw_lock);
 636         if (!fw_priv->fw->size || test_bit(FW_STATUS_ABORT, &fw_priv->status))
 637                 retval = -ENOENT;
 638         fw_priv->fw = NULL;
 639         mutex_unlock(&fw_lock);
 640
 641         device_remove_file(f_dev, &dev_attr_loading);
 642 err_del_bin_attr:
 643         device_remove_bin_file(f_dev, &firmware_attr_data);
 644 err_del_dev:
 645         device_del(f_dev);
 646 err_put_dev:
 647         put_device(f_dev);
 648         return retval;
 649 }
 650
 651 /**
 652  * request_firmware: - send firmware request and wait for it
 653  * @firmware_p: pointer to firmware image
 654  * @name: name of firmware file
 655  * @device: device for which firmware is being loaded
 656  *
 657  *      @firmware_p will be used to return a firmware image by the name
 658  *      of @name for device @device.
 659  *
 660  *      Should be called from user context where sleeping is allowed.
 661  *
 662  *      @name will be used as $FIRMWARE in the uevent environment and
 663  *      should be distinctive enough not to be confused with any other
 664  *      firmware image for this or any other device.
 665  **/
 666 int
 667 request_firmware(const struct firmware **firmware_p, const char *name,
 668                  struct device *device)
 669 {
 670         struct firmware_priv *fw_priv;
 671         int ret;
 672
 673         fw_priv = _request_firmware_prepare(firmware_p, name, device, true,
 674                                             false);
 675         if (IS_ERR_OR_NULL(fw_priv))
 676                 return PTR_RET(fw_priv);
 677
 678         ret = usermodehelper_read_trylock();
 679         if (ret) {
 680                 kfree(fw_priv);
 681                 dev_err(device, "firmware: %s will not be loaded\n", name);
 682         } else {
 683                 ret = _request_firmware_load(fw_priv, true,
 684                                         firmware_loading_timeout());
 685                 usermodehelper_read_unlock();
 686         }
 687         if (ret)
 688                 _request_firmware_cleanup(firmware_p);
 689
 690         return ret;
 691 }
 692
 693 /**
 694  * release_firmware: - release the resource associated with a firmware image
 695  * @fw: firmware resource to release
 696  **/
 697 void release_firmware(const struct firmware *fw)
 698 {
 699         if (fw) {
 700                 if (!fw_is_builtin_firmware(fw))
 701                         firmware_free_data(fw);
 702                 kfree(fw);
 703         }
 704 }
 705
 706 /* Async support */
 707 struct firmware_work {
 708         struct work_struct work;
 709         struct module *module;
 710         const char *name;
 711         struct device *device;
 712         void *context;
 713         void (*cont)(const struct firmware *fw, void *context);
 714         bool uevent;
 715 };
 716
 717 static void request_firmware_work_func(struct work_struct *work)
 718 {
 719         struct firmware_work *fw_work;
 720         const struct firmware *fw;
 721         struct firmware_priv *fw_priv;
 722         long timeout;
 723         int ret;
 724
 725         fw_work = container_of(work, struct firmware_work, work);
 726         fw_priv = _request_firmware_prepare(&fw, fw_work->name, fw_work->device,
 727                         fw_work->uevent, true);
 728         if (IS_ERR_OR_NULL(fw_priv)) {
 729                 ret = PTR_RET(fw_priv);
 730                 goto out;
 731         }
 732
 733         timeout = usermodehelper_read_lock_wait(firmware_loading_timeout());
 734         if (timeout) {
 735                 ret = _request_firmware_load(fw_priv, fw_work->uevent, timeout);
 736                 usermodehelper_read_unlock();
 737         } else {
 738                 dev_dbg(fw_work->device, "firmware: %s loading timed out\n",
 739                         fw_work->name);
 740                 ret = -EAGAIN;
 741         }
 742         if (ret)
 743                 _request_firmware_cleanup(&fw);
 744
 745  out:
 746         fw_work->cont(fw, fw_work->context);
 747
 748         module_put(fw_work->module);
 749         kfree(fw_work);
 750 }
 751
 752 /**
 753  * request_firmware_nowait - asynchronous version of request_firmware
 754  * @module: module requesting the firmware
 755  * @uevent: sends uevent to copy the firmware image if this flag
 756  *      is non-zero else the firmware copy must be done manually.
 757  * @name: name of firmware file
 758  * @device: device for which firmware is being loaded
 759  * @gfp: allocation flags
 760  * @context: will be passed over to @cont, and
 761  *      @fw may be %NULL if firmware request fails.
 762  * @cont: function will be called asynchronously when the firmware
 763  *      request is over.
 764  *
 765  *      Asynchronous variant of request_firmware() for user contexts where
 766  *      it is not possible to sleep for long time. It can't be called
 767  *      in atomic contexts.
 768  **/
 769 int
 770 request_firmware_nowait(
 771         struct module *module, bool uevent,
 772         const char *name, struct device *device, gfp_t gfp, void *context,
 773         void (*cont)(const struct firmware *fw, void *context))
 774 {
 775         struct firmware_work *fw_work;
 776
 777         fw_work = kzalloc(sizeof (struct firmware_work), gfp);
 778         if (!fw_work)
 779                 return -ENOMEM;
 780
 781         fw_work->module = module;
 782         fw_work->name = name;
 783         fw_work->device = device;
 784         fw_work->context = context;
 785         fw_work->cont = cont;
 786         fw_work->uevent = uevent;
 787
 788         if (!try_module_get(module)) {
 789                 kfree(fw_work);
 790                 return -EFAULT;
 791         }
 792
 793         INIT_WORK(&fw_work->work, request_firmware_work_func);
 794         schedule_work(&fw_work->work);
 795         return 0;
 796 }
 797
 798 static int __init firmware_class_init(void)
 799 {
 800         return class_register(&firmware_class);
 801 }
 802
 803 static void __exit firmware_class_exit(void)
 804 {
 805         class_unregister(&firmware_class);
 806 }
 807
 808 fs_initcall(firmware_class_init);
 809 module_exit(firmware_class_exit);
 810
 811 EXPORT_SYMBOL(release_firmware);
 812 EXPORT_SYMBOL(request_firmware);
 813 EXPORT_SYMBOL(request_firmware_nowait);