drivers/base/firmware_loader/main.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * main.c - Multi purpose firmware loading support
   4  *
   5  * Copyright (c) 2003 Manuel Estrada Sainz
   6  *
   7  * Please see Documentation/firmware_class/ for more information.
   8  *
   9  */
  10
  11 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  12
  13 #include <linux/capability.h>
  14 #include <linux/device.h>
  15 #include <linux/module.h>
  16 #include <linux/init.h>
  17 #include <linux/timer.h>
  18 #include <linux/vmalloc.h>
  19 #include <linux/interrupt.h>
  20 #include <linux/bitops.h>
  21 #include <linux/mutex.h>
  22 #include <linux/workqueue.h>
  23 #include <linux/highmem.h>
  24 #include <linux/firmware.h>
  25 #include <linux/slab.h>
  26 #include <linux/sched.h>
  27 #include <linux/file.h>
  28 #include <linux/list.h>
  29 #include <linux/fs.h>
  30 #include <linux/async.h>
  31 #include <linux/pm.h>
  32 #include <linux/suspend.h>
  33 #include <linux/syscore_ops.h>
  34 #include <linux/reboot.h>
  35 #include <linux/security.h>
  36
  37 #include <generated/utsrelease.h>
  38
  39 #include "../base.h"
  40 #include "firmware.h"
  41 #include "fallback.h"
  42
  43 MODULE_AUTHOR("Manuel Estrada Sainz");
  44 MODULE_DESCRIPTION("Multi purpose firmware loading support");
  45 MODULE_LICENSE("GPL");
  46
  47 struct firmware_cache {
  48         /* firmware_buf instance will be added into the below list */
  49         spinlock_t lock;
  50         struct list_head head;
  51         int state;
  52
  53 #ifdef CONFIG_PM_SLEEP
  54         /*
  55          * Names of firmware images which have been cached successfully
  56          * will be added into the below list so that device uncache
  57          * helper can trace which firmware images have been cached
  58          * before.
  59          */
  60         spinlock_t name_lock;
  61         struct list_head fw_names;
  62
  63         struct delayed_work work;
  64
  65         struct notifier_block   pm_notify;
  66 #endif
  67 };
  68
  69 struct fw_cache_entry {
  70         struct list_head list;
  71         const char *name;
  72 };
  73
  74 struct fw_name_devm {
  75         unsigned long magic;
  76         const char *name;
  77 };
  78
  79 static inline struct fw_priv *to_fw_priv(struct kref *ref)
  80 {
  81         return container_of(ref, struct fw_priv, ref);
  82 }
  83
  84 #define FW_LOADER_NO_CACHE      0
  85 #define FW_LOADER_START_CACHE   1
  86
  87 /* fw_lock could be moved to 'struct fw_sysfs' but since it is just
  88  * guarding for corner cases a global lock should be OK */
  89 DEFINE_MUTEX(fw_lock);
  90
  91 static struct firmware_cache fw_cache;
  92
  93 /* Builtin firmware support */
  94
  95 #ifdef CONFIG_FW_LOADER
  96
  97 extern struct builtin_fw __start_builtin_fw[];
  98 extern struct builtin_fw __end_builtin_fw[];
  99
 100 static void fw_copy_to_prealloc_buf(struct firmware *fw,
 101                                     void *buf, size_t size)
 102 {
 103         if (!buf || size < fw->size)
 104                 return;
 105         memcpy(buf, fw->data, fw->size);
 106 }
 107
 108 static bool fw_get_builtin_firmware(struct firmware *fw, const char *name,
 109                                     void *buf, size_t size)
 110 {
 111         struct builtin_fw *b_fw;
 112
 113         for (b_fw = __start_builtin_fw; b_fw != __end_builtin_fw; b_fw++) {
 114                 if (strcmp(name, b_fw->name) == 0) {
 115                         fw->size = b_fw->size;
 116                         fw->data = b_fw->data;
 117                         fw_copy_to_prealloc_buf(fw, buf, size);
 118
 119                         return true;
 120                 }
 121         }
 122
 123         return false;
 124 }
 125
 126 static bool fw_is_builtin_firmware(const struct firmware *fw)
 127 {
 128         struct builtin_fw *b_fw;
 129
 130         for (b_fw = __start_builtin_fw; b_fw != __end_builtin_fw; b_fw++)
 131                 if (fw->data == b_fw->data)
 132                         return true;
 133
 134         return false;
 135 }
 136
 137 #else /* Module case - no builtin firmware support */
 138
 139 static inline bool fw_get_builtin_firmware(struct firmware *fw,
 140                                            const char *name, void *buf,
 141                                            size_t size)
 142 {
 143         return false;
 144 }
 145
 146 static inline bool fw_is_builtin_firmware(const struct firmware *fw)
 147 {
 148         return false;
 149 }
 150 #endif
 151
 152 static void fw_state_init(struct fw_priv *fw_priv)
 153 {
 154         struct fw_state *fw_st = &fw_priv->fw_st;
 155
 156         init_completion(&fw_st->completion);
 157         fw_st->status = FW_STATUS_UNKNOWN;
 158 }
 159
 160 static inline int fw_state_wait(struct fw_priv *fw_priv)
 161 {
 162         return __fw_state_wait_common(fw_priv, MAX_SCHEDULE_TIMEOUT);
 163 }
 164
 165 static int fw_cache_piggyback_on_request(const char *name);
 166
 167 static struct fw_priv *__allocate_fw_priv(const char *fw_name,
 168                                           struct firmware_cache *fwc,
 169                                           void *dbuf, size_t size)
 170 {
 171         struct fw_priv *fw_priv;
 172
 173         fw_priv = kzalloc(sizeof(*fw_priv), GFP_ATOMIC);
 174         if (!fw_priv)
 175                 return NULL;
 176
 177         fw_priv->fw_name = kstrdup_const(fw_name, GFP_ATOMIC);
 178         if (!fw_priv->fw_name) {
 179                 kfree(fw_priv);
 180                 return NULL;
 181         }
 182
 183         kref_init(&fw_priv->ref);
 184         fw_priv->fwc = fwc;
 185         fw_priv->data = dbuf;
 186         fw_priv->allocated_size = size;
 187         fw_state_init(fw_priv);
 188 #ifdef CONFIG_FW_LOADER_USER_HELPER
 189         INIT_LIST_HEAD(&fw_priv->pending_list);
 190 #endif
 191
 192         pr_debug("%s: fw-%s fw_priv=%p\n", __func__, fw_name, fw_priv);
 193
 194         return fw_priv;
 195 }
 196
 197 static struct fw_priv *__lookup_fw_priv(const char *fw_name)
 198 {
 199         struct fw_priv *tmp;
 200         struct firmware_cache *fwc = &fw_cache;
 201
 202         list_for_each_entry(tmp, &fwc->head, list)
 203                 if (!strcmp(tmp->fw_name, fw_name))
 204                         return tmp;
 205         return NULL;
 206 }
 207
 208 /* Returns 1 for batching firmware requests with the same name */
 209 static int alloc_lookup_fw_priv(const char *fw_name,
 210                                 struct firmware_cache *fwc,
 211                                 struct fw_priv **fw_priv, void *dbuf,
 212                                 size_t size, enum fw_opt opt_flags)
 213 {
 214         struct fw_priv *tmp;
 215
 216         spin_lock(&fwc->lock);
 217         if (!(opt_flags & FW_OPT_NOCACHE)) {
 218                 tmp = __lookup_fw_priv(fw_name);
 219                 if (tmp) {
 220                         kref_get(&tmp->ref);
 221                         spin_unlock(&fwc->lock);
 222                         *fw_priv = tmp;
 223                         pr_debug("batched request - sharing the same struct fw_priv and lookup for multiple requests\n");
 224                         return 1;
 225                 }
 226         }
 227
 228         tmp = __allocate_fw_priv(fw_name, fwc, dbuf, size);
 229         if (tmp) {
 230                 INIT_LIST_HEAD(&tmp->list);
 231                 if (!(opt_flags & FW_OPT_NOCACHE))
 232                         list_add(&tmp->list, &fwc->head);
 233         }
 234         spin_unlock(&fwc->lock);
 235
 236         *fw_priv = tmp;
 237
 238         return tmp ? 0 : -ENOMEM;
 239 }
 240
 241 static void __free_fw_priv(struct kref *ref)
 242         __releases(&fwc->lock)
 243 {
 244         struct fw_priv *fw_priv = to_fw_priv(ref);
 245         struct firmware_cache *fwc = fw_priv->fwc;
 246
 247         pr_debug("%s: fw-%s fw_priv=%p data=%p size=%u\n",
 248                  __func__, fw_priv->fw_name, fw_priv, fw_priv->data,
 249                  (unsigned int)fw_priv->size);
 250
 251         list_del(&fw_priv->list);
 252         spin_unlock(&fwc->lock);
 253
 254 #ifdef CONFIG_FW_LOADER_USER_HELPER
 255         if (fw_priv->is_paged_buf) {
 256                 int i;
 257                 vunmap(fw_priv->data);
 258                 for (i = 0; i < fw_priv->nr_pages; i++)
 259                         __free_page(fw_priv->pages[i]);
 260                 vfree(fw_priv->pages);
 261         } else
 262 #endif
 263         if (!fw_priv->allocated_size)
 264                 vfree(fw_priv->data);
 265         kfree_const(fw_priv->fw_name);
 266         kfree(fw_priv);
 267 }
 268
 269 static void free_fw_priv(struct fw_priv *fw_priv)
 270 {
 271         struct firmware_cache *fwc = fw_priv->fwc;
 272         spin_lock(&fwc->lock);
 273         if (!kref_put(&fw_priv->ref, __free_fw_priv))
 274                 spin_unlock(&fwc->lock);
 275 }
 276
 277 /* direct firmware loading support */
 278 static char fw_path_para[256];
 279 static const char * const fw_path[] = {
 280         fw_path_para,
 281         "/lib/firmware/updates/" UTS_RELEASE,
 282         "/lib/firmware/updates",
 283         "/lib/firmware/" UTS_RELEASE,
 284         "/lib/firmware"
 285 };
 286
 287 /*
 288  * Typical usage is that passing 'firmware_class.path=$CUSTOMIZED_PATH'
 289  * from kernel command line because firmware_class is generally built in
 290  * kernel instead of module.
 291  */
 292 module_param_string(path, fw_path_para, sizeof(fw_path_para), 0644);
 293 MODULE_PARM_DESC(path, "customized firmware image search path with a higher priority than default path");
 294
 295 static int
 296 fw_get_filesystem_firmware(struct device *device, struct fw_priv *fw_priv)
 297 {
 298         loff_t size;
 299         int i, len;
 300         int rc = -ENOENT;
 301         char *path;
 302         enum kernel_read_file_id id = READING_FIRMWARE;
 303         size_t msize = INT_MAX;
 304
 305         /* Already populated data member means we're loading into a buffer */
 306         if (fw_priv->data) {
 307                 id = READING_FIRMWARE_PREALLOC_BUFFER;
 308                 msize = fw_priv->allocated_size;
 309         }
 310
 311         path = __getname();
 312         if (!path)
 313                 return -ENOMEM;
 314
 315         for (i = 0; i < ARRAY_SIZE(fw_path); i++) {
 316                 /* skip the unset customized path */
 317                 if (!fw_path[i][0])
 318                         continue;
 319
 320                 len = snprintf(path, PATH_MAX, "%s/%s",
 321                                fw_path[i], fw_priv->fw_name);
 322                 if (len >= PATH_MAX) {
 323                         rc = -ENAMETOOLONG;
 324                         break;
 325                 }
 326
 327                 fw_priv->size = 0;
 328                 rc = kernel_read_file_from_path(path, &fw_priv->data, &size,
 329                                                 msize, id);
 330                 if (rc) {
 331                         if (rc == -ENOENT)
 332                                 dev_dbg(device, "loading %s failed with error %d\n",
 333                                          path, rc);
 334                         else
 335                                 dev_warn(device, "loading %s failed with error %d\n",
 336                                          path, rc);
 337                         continue;
 338                 }
 339                 dev_dbg(device, "direct-loading %s\n", fw_priv->fw_name);
 340                 fw_priv->size = size;
 341                 fw_state_done(fw_priv);
 342                 break;
 343         }
 344         __putname(path);
 345
 346         return rc;
 347 }
 348
 349 /* firmware holds the ownership of pages */
 350 static void firmware_free_data(const struct firmware *fw)
 351 {
 352         /* Loaded directly? */
 353         if (!fw->priv) {
 354                 vfree(fw->data);
 355                 return;
 356         }
 357         free_fw_priv(fw->priv);
 358 }
 359
 360 /* store the pages buffer info firmware from buf */
 361 static void fw_set_page_data(struct fw_priv *fw_priv, struct firmware *fw)
 362 {
 363         fw->priv = fw_priv;
 364 #ifdef CONFIG_FW_LOADER_USER_HELPER
 365         fw->pages = fw_priv->pages;
 366 #endif
 367         fw->size = fw_priv->size;
 368         fw->data = fw_priv->data;
 369
 370         pr_debug("%s: fw-%s fw_priv=%p data=%p size=%u\n",
 371                  __func__, fw_priv->fw_name, fw_priv, fw_priv->data,
 372                  (unsigned int)fw_priv->size);
 373 }
 374
 375 #ifdef CONFIG_PM_SLEEP
 376 static void fw_name_devm_release(struct device *dev, void *res)
 377 {
 378         struct fw_name_devm *fwn = res;
 379
 380         if (fwn->magic == (unsigned long)&fw_cache)
 381                 pr_debug("%s: fw_name-%s devm-%p released\n",
 382                                 __func__, fwn->name, res);
 383         kfree_const(fwn->name);
 384 }
 385
 386 static int fw_devm_match(struct device *dev, void *res,
 387                 void *match_data)
 388 {
 389         struct fw_name_devm *fwn = res;
 390
 391         return (fwn->magic == (unsigned long)&fw_cache) &&
 392                 !strcmp(fwn->name, match_data);
 393 }
 394
 395 static struct fw_name_devm *fw_find_devm_name(struct device *dev,
 396                 const char *name)
 397 {
 398         struct fw_name_devm *fwn;
 399
 400         fwn = devres_find(dev, fw_name_devm_release,
 401                           fw_devm_match, (void *)name);
 402         return fwn;
 403 }
 404
 405 static bool fw_cache_is_setup(struct device *dev, const char *name)
 406 {
 407         struct fw_name_devm *fwn;
 408
 409         fwn = fw_find_devm_name(dev, name);
 410         if (fwn)
 411                 return true;
 412
 413         return false;
 414 }
 415
 416 /* add firmware name into devres list */
 417 static int fw_add_devm_name(struct device *dev, const char *name)
 418 {
 419         struct fw_name_devm *fwn;
 420
 421         if (fw_cache_is_setup(dev, name))
 422                 return 0;
 423
 424         fwn = devres_alloc(fw_name_devm_release, sizeof(struct fw_name_devm),
 425                            GFP_KERNEL);
 426         if (!fwn)
 427                 return -ENOMEM;
 428         fwn->name = kstrdup_const(name, GFP_KERNEL);
 429         if (!fwn->name) {
 430                 devres_free(fwn);
 431                 return -ENOMEM;
 432         }
 433
 434         fwn->magic = (unsigned long)&fw_cache;
 435         devres_add(dev, fwn);
 436
 437         return 0;
 438 }
 439 #else
 440 static bool fw_cache_is_setup(struct device *dev, const char *name)
 441 {
 442         return false;
 443 }
 444
 445 static int fw_add_devm_name(struct device *dev, const char *name)
 446 {
 447         return 0;
 448 }
 449 #endif
 450
 451 int assign_fw(struct firmware *fw, struct device *device,
 452               enum fw_opt opt_flags)
 453 {
 454         struct fw_priv *fw_priv = fw->priv;
 455         int ret;
 456
 457         mutex_lock(&fw_lock);
 458         if (!fw_priv->size || fw_state_is_aborted(fw_priv)) {
 459                 mutex_unlock(&fw_lock);
 460                 return -ENOENT;
 461         }
 462
 463         /*
 464          * add firmware name into devres list so that we can auto cache
 465          * and uncache firmware for device.
 466          *
 467          * device may has been deleted already, but the problem
 468          * should be fixed in devres or driver core.
 469          */
 470         /* don't cache firmware handled without uevent */
 471         if (device && (opt_flags & FW_OPT_UEVENT) &&
 472             !(opt_flags & FW_OPT_NOCACHE)) {
 473                 ret = fw_add_devm_name(device, fw_priv->fw_name);
 474                 if (ret) {
 475                         mutex_unlock(&fw_lock);
 476                         return ret;
 477                 }
 478         }
 479
 480         /*
 481          * After caching firmware image is started, let it piggyback
 482          * on request firmware.
 483          */
 484         if (!(opt_flags & FW_OPT_NOCACHE) &&
 485             fw_priv->fwc->state == FW_LOADER_START_CACHE) {
 486                 if (fw_cache_piggyback_on_request(fw_priv->fw_name))
 487                         kref_get(&fw_priv->ref);
 488         }
 489
 490         /* pass the pages buffer to driver at the last minute */
 491         fw_set_page_data(fw_priv, fw);
 492         mutex_unlock(&fw_lock);
 493         return 0;
 494 }
 495
 496 /* prepare firmware and firmware_buf structs;
 497  * return 0 if a firmware is already assigned, 1 if need to load one,
 498  * or a negative error code
 499  */
 500 static int
 501 _request_firmware_prepare(struct firmware **firmware_p, const char *name,
 502                           struct device *device, void *dbuf, size_t size,
 503                           enum fw_opt opt_flags)
 504 {
 505         struct firmware *firmware;
 506         struct fw_priv *fw_priv;
 507         int ret;
 508
 509         *firmware_p = firmware = kzalloc(sizeof(*firmware), GFP_KERNEL);
 510         if (!firmware) {
 511                 dev_err(device, "%s: kmalloc(struct firmware) failed\n",
 512                         __func__);
 513                 return -ENOMEM;
 514         }
 515
 516         if (fw_get_builtin_firmware(firmware, name, dbuf, size)) {
 517                 dev_dbg(device, "using built-in %s\n", name);
 518                 return 0; /* assigned */
 519         }
 520
 521         ret = alloc_lookup_fw_priv(name, &fw_cache, &fw_priv, dbuf, size,
 522                                   opt_flags);
 523
 524         /*
 525          * bind with 'priv' now to avoid warning in failure path
 526          * of requesting firmware.
 527          */
 528         firmware->priv = fw_priv;
 529
 530         if (ret > 0) {
 531                 ret = fw_state_wait(fw_priv);
 532                 if (!ret) {
 533                         fw_set_page_data(fw_priv, firmware);
 534                         return 0; /* assigned */
 535                 }
 536         }
 537
 538         if (ret < 0)
 539                 return ret;
 540         return 1; /* need to load */
 541 }
 542
 543 /*
 544  * Batched requests need only one wake, we need to do this step last due to the
 545  * fallback mechanism. The buf is protected with kref_get(), and it won't be
 546  * released until the last user calls release_firmware().
 547  *
 548  * Failed batched requests are possible as well, in such cases we just share
 549  * the struct fw_priv and won't release it until all requests are woken
 550  * and have gone through this same path.
 551  */
 552 static void fw_abort_batch_reqs(struct firmware *fw)
 553 {
 554         struct fw_priv *fw_priv;
 555
 556         /* Loaded directly? */
 557         if (!fw || !fw->priv)
 558                 return;
 559
 560         fw_priv = fw->priv;
 561         mutex_lock(&fw_lock);
 562         if (!fw_state_is_aborted(fw_priv))
 563                 fw_state_aborted(fw_priv);
 564         mutex_unlock(&fw_lock);
 565 }
 566
 567 /* called from request_firmware() and request_firmware_work_func() */
 568 static int
 569 _request_firmware(const struct firmware **firmware_p, const char *name,
 570                   struct device *device, void *buf, size_t size,
 571                   enum fw_opt opt_flags)
 572 {
 573         struct firmware *fw = NULL;
 574         int ret;
 575
 576         if (!firmware_p)
 577                 return -EINVAL;
 578
 579         if (!name || name[0] == '\0') {
 580                 ret = -EINVAL;
 581                 goto out;
 582         }
 583
 584         ret = _request_firmware_prepare(&fw, name, device, buf, size,
 585                                         opt_flags);
 586         if (ret <= 0) /* error or already assigned */
 587                 goto out;
 588
 589         ret = fw_get_filesystem_firmware(device, fw->priv);
 590         if (ret) {
 591                 if (!(opt_flags & FW_OPT_NO_WARN))
 592                         dev_warn(device,
 593                                  "Direct firmware load for %s failed with error %d\n",
 594                                  name, ret);
 595                 ret = firmware_fallback_sysfs(fw, name, device, opt_flags, ret);
 596         } else
 597                 ret = assign_fw(fw, device, opt_flags);
 598
 599  out:
 600         if (ret < 0) {
 601                 fw_abort_batch_reqs(fw);
 602                 release_firmware(fw);
 603                 fw = NULL;
 604         }
 605
 606         *firmware_p = fw;
 607         return ret;
 608 }
 609
 610 /**
 611  * request_firmware() - send firmware request and wait for it
 612  * @firmware_p: pointer to firmware image
 613  * @name: name of firmware file
 614  * @device: device for which firmware is being loaded
 615  *
 616  *      @firmware_p will be used to return a firmware image by the name
 617  *      of @name for device @device.
 618  *
 619  *      Should be called from user context where sleeping is allowed.
 620  *
 621  *      @name will be used as $FIRMWARE in the uevent environment and
 622  *      should be distinctive enough not to be confused with any other
 623  *      firmware image for this or any other device.
 624  *
 625  *      Caller must hold the reference count of @device.
 626  *
 627  *      The function can be called safely inside device's suspend and
 628  *      resume callback.
 629  **/
 630 int
 631 request_firmware(const struct firmware **firmware_p, const char *name,
 632                  struct device *device)
 633 {
 634         int ret;
 635
 636         /* Need to pin this module until return */
 637         __module_get(THIS_MODULE);
 638         ret = _request_firmware(firmware_p, name, device, NULL, 0,
 639                                 FW_OPT_UEVENT);
 640         module_put(THIS_MODULE);
 641         return ret;
 642 }
 643 EXPORT_SYMBOL(request_firmware);
 644
 645 /**
 646  * firmware_request_nowarn() - request for an optional fw module
 647  * @firmware: pointer to firmware image
 648  * @name: name of firmware file
 649  * @device: device for which firmware is being loaded
 650  *
 651  * This function is similar in behaviour to request_firmware(), except
 652  * it doesn't produce warning messages when the file is not found.
 653  * The sysfs fallback mechanism is enabled if direct filesystem lookup fails,
 654  * however, however failures to find the firmware file with it are still
 655  * suppressed. It is therefore up to the driver to check for the return value
 656  * of this call and to decide when to inform the users of errors.
 657  **/
 658 int firmware_request_nowarn(const struct firmware **firmware, const char *name,
 659                             struct device *device)
 660 {
 661         int ret;
 662
 663         /* Need to pin this module until return */
 664         __module_get(THIS_MODULE);
 665         ret = _request_firmware(firmware, name, device, NULL, 0,
 666                                 FW_OPT_UEVENT | FW_OPT_NO_WARN);
 667         module_put(THIS_MODULE);
 668         return ret;
 669 }
 670 EXPORT_SYMBOL_GPL(firmware_request_nowarn);
 671
 672 /**
 673  * request_firmware_direct() - load firmware directly without usermode helper
 674  * @firmware_p: pointer to firmware image
 675  * @name: name of firmware file
 676  * @device: device for which firmware is being loaded
 677  *
 678  * This function works pretty much like request_firmware(), but this doesn't
 679  * fall back to usermode helper even if the firmware couldn't be loaded
 680  * directly from fs.  Hence it's useful for loading optional firmwares, which
 681  * aren't always present, without extra long timeouts of udev.
 682  **/
 683 int request_firmware_direct(const struct firmware **firmware_p,
 684                             const char *name, struct device *device)
 685 {
 686         int ret;
 687
 688         __module_get(THIS_MODULE);
 689         ret = _request_firmware(firmware_p, name, device, NULL, 0,
 690                                 FW_OPT_UEVENT | FW_OPT_NO_WARN |
 691                                 FW_OPT_NOFALLBACK);
 692         module_put(THIS_MODULE);
 693         return ret;
 694 }
 695 EXPORT_SYMBOL_GPL(request_firmware_direct);
 696
 697 /**
 698  * firmware_request_cache() - cache firmware for suspend so resume can use it
 699  * @name: name of firmware file
 700  * @device: device for which firmware should be cached for
 701  *
 702  * There are some devices with an optimization that enables the device to not
 703  * require loading firmware on system reboot. This optimization may still
 704  * require the firmware present on resume from suspend. This routine can be
 705  * used to ensure the firmware is present on resume from suspend in these
 706  * situations. This helper is not compatible with drivers which use
 707  * request_firmware_into_buf() or request_firmware_nowait() with no uevent set.
 708  **/
 709 int firmware_request_cache(struct device *device, const char *name)
 710 {
 711         int ret;
 712
 713         mutex_lock(&fw_lock);
 714         ret = fw_add_devm_name(device, name);
 715         mutex_unlock(&fw_lock);
 716
 717         return ret;
 718 }
 719 EXPORT_SYMBOL_GPL(firmware_request_cache);
 720
 721 /**
 722  * request_firmware_into_buf() - load firmware into a previously allocated buffer
 723  * @firmware_p: pointer to firmware image
 724  * @name: name of firmware file
 725  * @device: device for which firmware is being loaded and DMA region allocated
 726  * @buf: address of buffer to load firmware into
 727  * @size: size of buffer
 728  *
 729  * This function works pretty much like request_firmware(), but it doesn't
 730  * allocate a buffer to hold the firmware data. Instead, the firmware
 731  * is loaded directly into the buffer pointed to by @buf and the @firmware_p
 732  * data member is pointed at @buf.
 733  *
 734  * This function doesn't cache firmware either.
 735  */
 736 int
 737 request_firmware_into_buf(const struct firmware **firmware_p, const char *name,
 738                           struct device *device, void *buf, size_t size)
 739 {
 740         int ret;
 741
 742         if (fw_cache_is_setup(device, name))
 743                 return -EOPNOTSUPP;
 744
 745         __module_get(THIS_MODULE);
 746         ret = _request_firmware(firmware_p, name, device, buf, size,
 747                                 FW_OPT_UEVENT | FW_OPT_NOCACHE);
 748         module_put(THIS_MODULE);
 749         return ret;
 750 }
 751 EXPORT_SYMBOL(request_firmware_into_buf);
 752
 753 /**
 754  * release_firmware() - release the resource associated with a firmware image
 755  * @fw: firmware resource to release
 756  **/
 757 void release_firmware(const struct firmware *fw)
 758 {
 759         if (fw) {
 760                 if (!fw_is_builtin_firmware(fw))
 761                         firmware_free_data(fw);
 762                 kfree(fw);
 763         }
 764 }
 765 EXPORT_SYMBOL(release_firmware);
 766
 767 /* Async support */
 768 struct firmware_work {
 769         struct work_struct work;
 770         struct module *module;
 771         const char *name;
 772         struct device *device;
 773         void *context;
 774         void (*cont)(const struct firmware *fw, void *context);
 775         enum fw_opt opt_flags;
 776 };
 777
 778 static void request_firmware_work_func(struct work_struct *work)
 779 {
 780         struct firmware_work *fw_work;
 781         const struct firmware *fw;
 782
 783         fw_work = container_of(work, struct firmware_work, work);
 784
 785         _request_firmware(&fw, fw_work->name, fw_work->device, NULL, 0,
 786                           fw_work->opt_flags);
 787         fw_work->cont(fw, fw_work->context);
 788         put_device(fw_work->device); /* taken in request_firmware_nowait() */
 789
 790         module_put(fw_work->module);
 791         kfree_const(fw_work->name);
 792         kfree(fw_work);
 793 }
 794
 795 /**
 796  * request_firmware_nowait() - asynchronous version of request_firmware
 797  * @module: module requesting the firmware
 798  * @uevent: sends uevent to copy the firmware image if this flag
 799  *      is non-zero else the firmware copy must be done manually.
 800  * @name: name of firmware file
 801  * @device: device for which firmware is being loaded
 802  * @gfp: allocation flags
 803  * @context: will be passed over to @cont, and
 804  *      @fw may be %NULL if firmware request fails.
 805  * @cont: function will be called asynchronously when the firmware
 806  *      request is over.
 807  *
 808  *      Caller must hold the reference count of @device.
 809  *
 810  *      Asynchronous variant of request_firmware() for user contexts:
 811  *              - sleep for as small periods as possible since it may
 812  *                increase kernel boot time of built-in device drivers
 813  *                requesting firmware in their ->probe() methods, if
 814  *                @gfp is GFP_KERNEL.
 815  *
 816  *              - can't sleep at all if @gfp is GFP_ATOMIC.
 817  **/
 818 int
 819 request_firmware_nowait(
 820         struct module *module, bool uevent,
 821         const char *name, struct device *device, gfp_t gfp, void *context,
 822         void (*cont)(const struct firmware *fw, void *context))
 823 {
 824         struct firmware_work *fw_work;
 825
 826         fw_work = kzalloc(sizeof(struct firmware_work), gfp);
 827         if (!fw_work)
 828                 return -ENOMEM;
 829
 830         fw_work->module = module;
 831         fw_work->name = kstrdup_const(name, gfp);
 832         if (!fw_work->name) {
 833                 kfree(fw_work);
 834                 return -ENOMEM;
 835         }
 836         fw_work->device = device;
 837         fw_work->context = context;
 838         fw_work->cont = cont;
 839         fw_work->opt_flags = FW_OPT_NOWAIT |
 840                 (uevent ? FW_OPT_UEVENT : FW_OPT_USERHELPER);
 841
 842         if (!uevent && fw_cache_is_setup(device, name)) {
 843                 kfree_const(fw_work->name);
 844                 kfree(fw_work);
 845                 return -EOPNOTSUPP;
 846         }
 847
 848         if (!try_module_get(module)) {
 849                 kfree_const(fw_work->name);
 850                 kfree(fw_work);
 851                 return -EFAULT;
 852         }
 853
 854         get_device(fw_work->device);
 855         INIT_WORK(&fw_work->work, request_firmware_work_func);
 856         schedule_work(&fw_work->work);
 857         return 0;
 858 }
 859 EXPORT_SYMBOL(request_firmware_nowait);
 860
 861 #ifdef CONFIG_PM_SLEEP
 862 static ASYNC_DOMAIN_EXCLUSIVE(fw_cache_domain);
 863
 864 /**
 865  * cache_firmware() - cache one firmware image in kernel memory space
 866  * @fw_name: the firmware image name
 867  *
 868  * Cache firmware in kernel memory so that drivers can use it when
 869  * system isn't ready for them to request firmware image from userspace.
 870  * Once it returns successfully, driver can use request_firmware or its
 871  * nowait version to get the cached firmware without any interacting
 872  * with userspace
 873  *
 874  * Return 0 if the firmware image has been cached successfully
 875  * Return !0 otherwise
 876  *
 877  */
 878 static int cache_firmware(const char *fw_name)
 879 {
 880         int ret;
 881         const struct firmware *fw;
 882
 883         pr_debug("%s: %s\n", __func__, fw_name);
 884
 885         ret = request_firmware(&fw, fw_name, NULL);
 886         if (!ret)
 887                 kfree(fw);
 888
 889         pr_debug("%s: %s ret=%d\n", __func__, fw_name, ret);
 890
 891         return ret;
 892 }
 893
 894 static struct fw_priv *lookup_fw_priv(const char *fw_name)
 895 {
 896         struct fw_priv *tmp;
 897         struct firmware_cache *fwc = &fw_cache;
 898
 899         spin_lock(&fwc->lock);
 900         tmp = __lookup_fw_priv(fw_name);
 901         spin_unlock(&fwc->lock);
 902
 903         return tmp;
 904 }
 905
 906 /**
 907  * uncache_firmware() - remove one cached firmware image
 908  * @fw_name: the firmware image name
 909  *
 910  * Uncache one firmware image which has been cached successfully
 911  * before.
 912  *
 913  * Return 0 if the firmware cache has been removed successfully
 914  * Return !0 otherwise
 915  *
 916  */
 917 static int uncache_firmware(const char *fw_name)
 918 {
 919         struct fw_priv *fw_priv;
 920         struct firmware fw;
 921
 922         pr_debug("%s: %s\n", __func__, fw_name);
 923
 924         if (fw_get_builtin_firmware(&fw, fw_name, NULL, 0))
 925                 return 0;
 926
 927         fw_priv = lookup_fw_priv(fw_name);
 928         if (fw_priv) {
 929                 free_fw_priv(fw_priv);
 930                 return 0;
 931         }
 932
 933         return -EINVAL;
 934 }
 935
 936 static struct fw_cache_entry *alloc_fw_cache_entry(const char *name)
 937 {
 938         struct fw_cache_entry *fce;
 939
 940         fce = kzalloc(sizeof(*fce), GFP_ATOMIC);
 941         if (!fce)
 942                 goto exit;
 943
 944         fce->name = kstrdup_const(name, GFP_ATOMIC);
 945         if (!fce->name) {
 946                 kfree(fce);
 947                 fce = NULL;
 948                 goto exit;
 949         }
 950 exit:
 951         return fce;
 952 }
 953
 954 static int __fw_entry_found(const char *name)
 955 {
 956         struct firmware_cache *fwc = &fw_cache;
 957         struct fw_cache_entry *fce;
 958
 959         list_for_each_entry(fce, &fwc->fw_names, list) {
 960                 if (!strcmp(fce->name, name))
 961                         return 1;
 962         }
 963         return 0;
 964 }
 965
 966 static int fw_cache_piggyback_on_request(const char *name)
 967 {
 968         struct firmware_cache *fwc = &fw_cache;
 969         struct fw_cache_entry *fce;
 970         int ret = 0;
 971
 972         spin_lock(&fwc->name_lock);
 973         if (__fw_entry_found(name))
 974                 goto found;
 975
 976         fce = alloc_fw_cache_entry(name);
 977         if (fce) {
 978                 ret = 1;
 979                 list_add(&fce->list, &fwc->fw_names);
 980                 pr_debug("%s: fw: %s\n", __func__, name);
 981         }
 982 found:
 983         spin_unlock(&fwc->name_lock);
 984         return ret;
 985 }
 986
 987 static void free_fw_cache_entry(struct fw_cache_entry *fce)
 988 {
 989         kfree_const(fce->name);
 990         kfree(fce);
 991 }
 992
 993 static void __async_dev_cache_fw_image(void *fw_entry,
 994                                        async_cookie_t cookie)
 995 {
 996         struct fw_cache_entry *fce = fw_entry;
 997         struct firmware_cache *fwc = &fw_cache;
 998         int ret;
 999
1000         ret = cache_firmware(fce->name);
1001         if (ret) {
1002                 spin_lock(&fwc->name_lock);
1003                 list_del(&fce->list);
1004                 spin_unlock(&fwc->name_lock);
1005
1006                 free_fw_cache_entry(fce);
1007         }
1008 }
1009
1010 /* called with dev->devres_lock held */
1011 static void dev_create_fw_entry(struct device *dev, void *res,
1012                                 void *data)
1013 {
1014         struct fw_name_devm *fwn = res;
1015         const char *fw_name = fwn->name;
1016         struct list_head *head = data;
1017         struct fw_cache_entry *fce;
1018
1019         fce = alloc_fw_cache_entry(fw_name);
1020         if (fce)
1021                 list_add(&fce->list, head);
1022 }
1023
1024 static int devm_name_match(struct device *dev, void *res,
1025                            void *match_data)
1026 {
1027         struct fw_name_devm *fwn = res;
1028         return (fwn->magic == (unsigned long)match_data);
1029 }
1030
1031 static void dev_cache_fw_image(struct device *dev, void *data)
1032 {
1033         LIST_HEAD(todo);
1034         struct fw_cache_entry *fce;
1035         struct fw_cache_entry *fce_next;
1036         struct firmware_cache *fwc = &fw_cache;
1037
1038         devres_for_each_res(dev, fw_name_devm_release,
1039                             devm_name_match, &fw_cache,
1040                             dev_create_fw_entry, &todo);
1041
1042         list_for_each_entry_safe(fce, fce_next, &todo, list) {
1043                 list_del(&fce->list);
1044
1045                 spin_lock(&fwc->name_lock);
1046                 /* only one cache entry for one firmware */
1047                 if (!__fw_entry_found(fce->name)) {
1048                         list_add(&fce->list, &fwc->fw_names);
1049                 } else {
1050                         free_fw_cache_entry(fce);
1051                         fce = NULL;
1052                 }
1053                 spin_unlock(&fwc->name_lock);
1054
1055                 if (fce)
1056                         async_schedule_domain(__async_dev_cache_fw_image,
1057                                               (void *)fce,
1058                                               &fw_cache_domain);
1059         }
1060 }
1061
1062 static void __device_uncache_fw_images(void)
1063 {
1064         struct firmware_cache *fwc = &fw_cache;
1065         struct fw_cache_entry *fce;
1066
1067         spin_lock(&fwc->name_lock);
1068         while (!list_empty(&fwc->fw_names)) {
1069                 fce = list_entry(fwc->fw_names.next,
1070                                 struct fw_cache_entry, list);
1071                 list_del(&fce->list);
1072                 spin_unlock(&fwc->name_lock);
1073
1074                 uncache_firmware(fce->name);
1075                 free_fw_cache_entry(fce);
1076
1077                 spin_lock(&fwc->name_lock);
1078         }
1079         spin_unlock(&fwc->name_lock);
1080 }
1081
1082 /**
1083  * device_cache_fw_images() - cache devices' firmware
1084  *
1085  * If one device called request_firmware or its nowait version
1086  * successfully before, the firmware names are recored into the
1087  * device's devres link list, so device_cache_fw_images can call
1088  * cache_firmware() to cache these firmwares for the device,
1089  * then the device driver can load its firmwares easily at
1090  * time when system is not ready to complete loading firmware.
1091  */
1092 static void device_cache_fw_images(void)
1093 {
1094         struct firmware_cache *fwc = &fw_cache;
1095         DEFINE_WAIT(wait);
1096
1097         pr_debug("%s\n", __func__);
1098
1099         /* cancel uncache work */
1100         cancel_delayed_work_sync(&fwc->work);
1101
1102         fw_fallback_set_cache_timeout();
1103
1104         mutex_lock(&fw_lock);
1105         fwc->state = FW_LOADER_START_CACHE;
1106         dpm_for_each_dev(NULL, dev_cache_fw_image);
1107         mutex_unlock(&fw_lock);
1108
1109         /* wait for completion of caching firmware for all devices */
1110         async_synchronize_full_domain(&fw_cache_domain);
1111
1112         fw_fallback_set_default_timeout();
1113 }
1114
1115 /**
1116  * device_uncache_fw_images() - uncache devices' firmware
1117  *
1118  * uncache all firmwares which have been cached successfully
1119  * by device_uncache_fw_images earlier
1120  */
1121 static void device_uncache_fw_images(void)
1122 {
1123         pr_debug("%s\n", __func__);
1124         __device_uncache_fw_images();
1125 }
1126
1127 static void device_uncache_fw_images_work(struct work_struct *work)
1128 {
1129         device_uncache_fw_images();
1130 }
1131
1132 /**
1133  * device_uncache_fw_images_delay() - uncache devices firmwares
1134  * @delay: number of milliseconds to delay uncache device firmwares
1135  *
1136  * uncache all devices's firmwares which has been cached successfully
1137  * by device_cache_fw_images after @delay milliseconds.
1138  */
1139 static void device_uncache_fw_images_delay(unsigned long delay)
1140 {
1141         queue_delayed_work(system_power_efficient_wq, &fw_cache.work,
1142                            msecs_to_jiffies(delay));
1143 }
1144
1145 static int fw_pm_notify(struct notifier_block *notify_block,
1146                         unsigned long mode, void *unused)
1147 {
1148         switch (mode) {
1149         case PM_HIBERNATION_PREPARE:
1150         case PM_SUSPEND_PREPARE:
1151         case PM_RESTORE_PREPARE:
1152                 /*
1153                  * kill pending fallback requests with a custom fallback
1154                  * to avoid stalling suspend.
1155                  */
1156                 kill_pending_fw_fallback_reqs(true);
1157                 device_cache_fw_images();
1158                 break;
1159
1160         case PM_POST_SUSPEND:
1161         case PM_POST_HIBERNATION:
1162         case PM_POST_RESTORE:
1163                 /*
1164                  * In case that system sleep failed and syscore_suspend is
1165                  * not called.
1166                  */
1167                 mutex_lock(&fw_lock);
1168                 fw_cache.state = FW_LOADER_NO_CACHE;
1169                 mutex_unlock(&fw_lock);
1170
1171                 device_uncache_fw_images_delay(10 * MSEC_PER_SEC);
1172                 break;
1173         }
1174
1175         return 0;
1176 }
1177
1178 /* stop caching firmware once syscore_suspend is reached */
1179 static int fw_suspend(void)
1180 {
1181         fw_cache.state = FW_LOADER_NO_CACHE;
1182         return 0;
1183 }
1184
1185 static struct syscore_ops fw_syscore_ops = {
1186         .suspend = fw_suspend,
1187 };
1188
1189 static int __init register_fw_pm_ops(void)
1190 {
1191         int ret;
1192
1193         spin_lock_init(&fw_cache.name_lock);
1194         INIT_LIST_HEAD(&fw_cache.fw_names);
1195
1196         INIT_DELAYED_WORK(&fw_cache.work,
1197                           device_uncache_fw_images_work);
1198
1199         fw_cache.pm_notify.notifier_call = fw_pm_notify;
1200         ret = register_pm_notifier(&fw_cache.pm_notify);
1201         if (ret)
1202                 return ret;
1203
1204         register_syscore_ops(&fw_syscore_ops);
1205
1206         return ret;
1207 }
1208
1209 static inline void unregister_fw_pm_ops(void)
1210 {
1211         unregister_syscore_ops(&fw_syscore_ops);
1212         unregister_pm_notifier(&fw_cache.pm_notify);
1213 }
1214 #else
1215 static int fw_cache_piggyback_on_request(const char *name)
1216 {
1217         return 0;
1218 }
1219 static inline int register_fw_pm_ops(void)
1220 {
1221         return 0;
1222 }
1223 static inline void unregister_fw_pm_ops(void)
1224 {
1225 }
1226 #endif
1227
1228 static void __init fw_cache_init(void)
1229 {
1230         spin_lock_init(&fw_cache.lock);
1231         INIT_LIST_HEAD(&fw_cache.head);
1232         fw_cache.state = FW_LOADER_NO_CACHE;
1233 }
1234
1235 static int fw_shutdown_notify(struct notifier_block *unused1,
1236                               unsigned long unused2, void *unused3)
1237 {
1238         /*
1239          * Kill all pending fallback requests to avoid both stalling shutdown,
1240          * and avoid a deadlock with the usermode_lock.
1241          */
1242         kill_pending_fw_fallback_reqs(false);
1243
1244         return NOTIFY_DONE;
1245 }
1246
1247 static struct notifier_block fw_shutdown_nb = {
1248         .notifier_call = fw_shutdown_notify,
1249 };
1250
1251 static int __init firmware_class_init(void)
1252 {
1253         int ret;
1254
1255         /* No need to unfold these on exit */
1256         fw_cache_init();
1257
1258         ret = register_fw_pm_ops();
1259         if (ret)
1260                 return ret;
1261
1262         ret = register_reboot_notifier(&fw_shutdown_nb);
1263         if (ret)
1264                 goto out;
1265
1266         return register_sysfs_loader();
1267
1268 out:
1269         unregister_fw_pm_ops();
1270         return ret;
1271 }
1272
1273 static void __exit firmware_class_exit(void)
1274 {
1275         unregister_fw_pm_ops();
1276         unregister_reboot_notifier(&fw_shutdown_nb);
1277         unregister_sysfs_loader();
1278 }
1279
1280 fs_initcall(firmware_class_init);
1281 module_exit(firmware_class_exit);