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         if (!fw_state_is_aborted(fw_priv))
 562                 fw_state_aborted(fw_priv);
 563 }
 564
 565 /* called from request_firmware() and request_firmware_work_func() */
 566 static int
 567 _request_firmware(const struct firmware **firmware_p, const char *name,
 568                   struct device *device, void *buf, size_t size,
 569                   enum fw_opt opt_flags)
 570 {
 571         struct firmware *fw = NULL;
 572         int ret;
 573
 574         if (!firmware_p)
 575                 return -EINVAL;
 576
 577         if (!name || name[0] == '\0') {
 578                 ret = -EINVAL;
 579                 goto out;
 580         }
 581
 582         ret = _request_firmware_prepare(&fw, name, device, buf, size,
 583                                         opt_flags);
 584         if (ret <= 0) /* error or already assigned */
 585                 goto out;
 586
 587         ret = fw_get_filesystem_firmware(device, fw->priv);
 588         if (ret) {
 589                 if (!(opt_flags & FW_OPT_NO_WARN))
 590                         dev_warn(device,
 591                                  "Direct firmware load for %s failed with error %d\n",
 592                                  name, ret);
 593                 ret = firmware_fallback_sysfs(fw, name, device, opt_flags, ret);
 594         } else
 595                 ret = assign_fw(fw, device, opt_flags);
 596
 597  out:
 598         if (ret < 0) {
 599                 fw_abort_batch_reqs(fw);
 600                 release_firmware(fw);
 601                 fw = NULL;
 602         }
 603
 604         *firmware_p = fw;
 605         return ret;
 606 }
 607
 608 /**
 609  * request_firmware() - send firmware request and wait for it
 610  * @firmware_p: pointer to firmware image
 611  * @name: name of firmware file
 612  * @device: device for which firmware is being loaded
 613  *
 614  *      @firmware_p will be used to return a firmware image by the name
 615  *      of @name for device @device.
 616  *
 617  *      Should be called from user context where sleeping is allowed.
 618  *
 619  *      @name will be used as $FIRMWARE in the uevent environment and
 620  *      should be distinctive enough not to be confused with any other
 621  *      firmware image for this or any other device.
 622  *
 623  *      Caller must hold the reference count of @device.
 624  *
 625  *      The function can be called safely inside device's suspend and
 626  *      resume callback.
 627  **/
 628 int
 629 request_firmware(const struct firmware **firmware_p, const char *name,
 630                  struct device *device)
 631 {
 632         int ret;
 633
 634         /* Need to pin this module until return */
 635         __module_get(THIS_MODULE);
 636         ret = _request_firmware(firmware_p, name, device, NULL, 0,
 637                                 FW_OPT_UEVENT);
 638         module_put(THIS_MODULE);
 639         return ret;
 640 }
 641 EXPORT_SYMBOL(request_firmware);
 642
 643 /**
 644  * firmware_request_nowarn() - request for an optional fw module
 645  * @firmware: pointer to firmware image
 646  * @name: name of firmware file
 647  * @device: device for which firmware is being loaded
 648  *
 649  * This function is similar in behaviour to request_firmware(), except
 650  * it doesn't produce warning messages when the file is not found.
 651  * The sysfs fallback mechanism is enabled if direct filesystem lookup fails,
 652  * however, however failures to find the firmware file with it are still
 653  * suppressed. It is therefore up to the driver to check for the return value
 654  * of this call and to decide when to inform the users of errors.
 655  **/
 656 int firmware_request_nowarn(const struct firmware **firmware, const char *name,
 657                             struct device *device)
 658 {
 659         int ret;
 660
 661         /* Need to pin this module until return */
 662         __module_get(THIS_MODULE);
 663         ret = _request_firmware(firmware, name, device, NULL, 0,
 664                                 FW_OPT_UEVENT | FW_OPT_NO_WARN);
 665         module_put(THIS_MODULE);
 666         return ret;
 667 }
 668 EXPORT_SYMBOL_GPL(firmware_request_nowarn);
 669
 670 /**
 671  * request_firmware_direct() - load firmware directly without usermode helper
 672  * @firmware_p: pointer to firmware image
 673  * @name: name of firmware file
 674  * @device: device for which firmware is being loaded
 675  *
 676  * This function works pretty much like request_firmware(), but this doesn't
 677  * fall back to usermode helper even if the firmware couldn't be loaded
 678  * directly from fs.  Hence it's useful for loading optional firmwares, which
 679  * aren't always present, without extra long timeouts of udev.
 680  **/
 681 int request_firmware_direct(const struct firmware **firmware_p,
 682                             const char *name, struct device *device)
 683 {
 684         int ret;
 685
 686         __module_get(THIS_MODULE);
 687         ret = _request_firmware(firmware_p, name, device, NULL, 0,
 688                                 FW_OPT_UEVENT | FW_OPT_NO_WARN |
 689                                 FW_OPT_NOFALLBACK);
 690         module_put(THIS_MODULE);
 691         return ret;
 692 }
 693 EXPORT_SYMBOL_GPL(request_firmware_direct);
 694
 695 /**
 696  * firmware_request_cache() - cache firmware for suspend so resume can use it
 697  * @name: name of firmware file
 698  * @device: device for which firmware should be cached for
 699  *
 700  * There are some devices with an optimization that enables the device to not
 701  * require loading firmware on system reboot. This optimization may still
 702  * require the firmware present on resume from suspend. This routine can be
 703  * used to ensure the firmware is present on resume from suspend in these
 704  * situations. This helper is not compatible with drivers which use
 705  * request_firmware_into_buf() or request_firmware_nowait() with no uevent set.
 706  **/
 707 int firmware_request_cache(struct device *device, const char *name)
 708 {
 709         int ret;
 710
 711         mutex_lock(&fw_lock);
 712         ret = fw_add_devm_name(device, name);
 713         mutex_unlock(&fw_lock);
 714
 715         return ret;
 716 }
 717 EXPORT_SYMBOL_GPL(firmware_request_cache);
 718
 719 /**
 720  * request_firmware_into_buf() - load firmware into a previously allocated buffer
 721  * @firmware_p: pointer to firmware image
 722  * @name: name of firmware file
 723  * @device: device for which firmware is being loaded and DMA region allocated
 724  * @buf: address of buffer to load firmware into
 725  * @size: size of buffer
 726  *
 727  * This function works pretty much like request_firmware(), but it doesn't
 728  * allocate a buffer to hold the firmware data. Instead, the firmware
 729  * is loaded directly into the buffer pointed to by @buf and the @firmware_p
 730  * data member is pointed at @buf.
 731  *
 732  * This function doesn't cache firmware either.
 733  */
 734 int
 735 request_firmware_into_buf(const struct firmware **firmware_p, const char *name,
 736                           struct device *device, void *buf, size_t size)
 737 {
 738         int ret;
 739
 740         if (fw_cache_is_setup(device, name))
 741                 return -EOPNOTSUPP;
 742
 743         __module_get(THIS_MODULE);
 744         ret = _request_firmware(firmware_p, name, device, buf, size,
 745                                 FW_OPT_UEVENT | FW_OPT_NOCACHE);
 746         module_put(THIS_MODULE);
 747         return ret;
 748 }
 749 EXPORT_SYMBOL(request_firmware_into_buf);
 750
 751 /**
 752  * release_firmware() - release the resource associated with a firmware image
 753  * @fw: firmware resource to release
 754  **/
 755 void release_firmware(const struct firmware *fw)
 756 {
 757         if (fw) {
 758                 if (!fw_is_builtin_firmware(fw))
 759                         firmware_free_data(fw);
 760                 kfree(fw);
 761         }
 762 }
 763 EXPORT_SYMBOL(release_firmware);
 764
 765 /* Async support */
 766 struct firmware_work {
 767         struct work_struct work;
 768         struct module *module;
 769         const char *name;
 770         struct device *device;
 771         void *context;
 772         void (*cont)(const struct firmware *fw, void *context);
 773         enum fw_opt opt_flags;
 774 };
 775
 776 static void request_firmware_work_func(struct work_struct *work)
 777 {
 778         struct firmware_work *fw_work;
 779         const struct firmware *fw;
 780
 781         fw_work = container_of(work, struct firmware_work, work);
 782
 783         _request_firmware(&fw, fw_work->name, fw_work->device, NULL, 0,
 784                           fw_work->opt_flags);
 785         fw_work->cont(fw, fw_work->context);
 786         put_device(fw_work->device); /* taken in request_firmware_nowait() */
 787
 788         module_put(fw_work->module);
 789         kfree_const(fw_work->name);
 790         kfree(fw_work);
 791 }
 792
 793 /**
 794  * request_firmware_nowait() - asynchronous version of request_firmware
 795  * @module: module requesting the firmware
 796  * @uevent: sends uevent to copy the firmware image if this flag
 797  *      is non-zero else the firmware copy must be done manually.
 798  * @name: name of firmware file
 799  * @device: device for which firmware is being loaded
 800  * @gfp: allocation flags
 801  * @context: will be passed over to @cont, and
 802  *      @fw may be %NULL if firmware request fails.
 803  * @cont: function will be called asynchronously when the firmware
 804  *      request is over.
 805  *
 806  *      Caller must hold the reference count of @device.
 807  *
 808  *      Asynchronous variant of request_firmware() for user contexts:
 809  *              - sleep for as small periods as possible since it may
 810  *                increase kernel boot time of built-in device drivers
 811  *                requesting firmware in their ->probe() methods, if
 812  *                @gfp is GFP_KERNEL.
 813  *
 814  *              - can't sleep at all if @gfp is GFP_ATOMIC.
 815  **/
 816 int
 817 request_firmware_nowait(
 818         struct module *module, bool uevent,
 819         const char *name, struct device *device, gfp_t gfp, void *context,
 820         void (*cont)(const struct firmware *fw, void *context))
 821 {
 822         struct firmware_work *fw_work;
 823
 824         fw_work = kzalloc(sizeof(struct firmware_work), gfp);
 825         if (!fw_work)
 826                 return -ENOMEM;
 827
 828         fw_work->module = module;
 829         fw_work->name = kstrdup_const(name, gfp);
 830         if (!fw_work->name) {
 831                 kfree(fw_work);
 832                 return -ENOMEM;
 833         }
 834         fw_work->device = device;
 835         fw_work->context = context;
 836         fw_work->cont = cont;
 837         fw_work->opt_flags = FW_OPT_NOWAIT |
 838                 (uevent ? FW_OPT_UEVENT : FW_OPT_USERHELPER);
 839
 840         if (!uevent && fw_cache_is_setup(device, name)) {
 841                 kfree_const(fw_work->name);
 842                 kfree(fw_work);
 843                 return -EOPNOTSUPP;
 844         }
 845
 846         if (!try_module_get(module)) {
 847                 kfree_const(fw_work->name);
 848                 kfree(fw_work);
 849                 return -EFAULT;
 850         }
 851
 852         get_device(fw_work->device);
 853         INIT_WORK(&fw_work->work, request_firmware_work_func);
 854         schedule_work(&fw_work->work);
 855         return 0;
 856 }
 857 EXPORT_SYMBOL(request_firmware_nowait);
 858
 859 #ifdef CONFIG_PM_SLEEP
 860 static ASYNC_DOMAIN_EXCLUSIVE(fw_cache_domain);
 861
 862 /**
 863  * cache_firmware() - cache one firmware image in kernel memory space
 864  * @fw_name: the firmware image name
 865  *
 866  * Cache firmware in kernel memory so that drivers can use it when
 867  * system isn't ready for them to request firmware image from userspace.
 868  * Once it returns successfully, driver can use request_firmware or its
 869  * nowait version to get the cached firmware without any interacting
 870  * with userspace
 871  *
 872  * Return 0 if the firmware image has been cached successfully
 873  * Return !0 otherwise
 874  *
 875  */
 876 static int cache_firmware(const char *fw_name)
 877 {
 878         int ret;
 879         const struct firmware *fw;
 880
 881         pr_debug("%s: %s\n", __func__, fw_name);
 882
 883         ret = request_firmware(&fw, fw_name, NULL);
 884         if (!ret)
 885                 kfree(fw);
 886
 887         pr_debug("%s: %s ret=%d\n", __func__, fw_name, ret);
 888
 889         return ret;
 890 }
 891
 892 static struct fw_priv *lookup_fw_priv(const char *fw_name)
 893 {
 894         struct fw_priv *tmp;
 895         struct firmware_cache *fwc = &fw_cache;
 896
 897         spin_lock(&fwc->lock);
 898         tmp = __lookup_fw_priv(fw_name);
 899         spin_unlock(&fwc->lock);
 900
 901         return tmp;
 902 }
 903
 904 /**
 905  * uncache_firmware() - remove one cached firmware image
 906  * @fw_name: the firmware image name
 907  *
 908  * Uncache one firmware image which has been cached successfully
 909  * before.
 910  *
 911  * Return 0 if the firmware cache has been removed successfully
 912  * Return !0 otherwise
 913  *
 914  */
 915 static int uncache_firmware(const char *fw_name)
 916 {
 917         struct fw_priv *fw_priv;
 918         struct firmware fw;
 919
 920         pr_debug("%s: %s\n", __func__, fw_name);
 921
 922         if (fw_get_builtin_firmware(&fw, fw_name, NULL, 0))
 923                 return 0;
 924
 925         fw_priv = lookup_fw_priv(fw_name);
 926         if (fw_priv) {
 927                 free_fw_priv(fw_priv);
 928                 return 0;
 929         }
 930
 931         return -EINVAL;
 932 }
 933
 934 static struct fw_cache_entry *alloc_fw_cache_entry(const char *name)
 935 {
 936         struct fw_cache_entry *fce;
 937
 938         fce = kzalloc(sizeof(*fce), GFP_ATOMIC);
 939         if (!fce)
 940                 goto exit;
 941
 942         fce->name = kstrdup_const(name, GFP_ATOMIC);
 943         if (!fce->name) {
 944                 kfree(fce);
 945                 fce = NULL;
 946                 goto exit;
 947         }
 948 exit:
 949         return fce;
 950 }
 951
 952 static int __fw_entry_found(const char *name)
 953 {
 954         struct firmware_cache *fwc = &fw_cache;
 955         struct fw_cache_entry *fce;
 956
 957         list_for_each_entry(fce, &fwc->fw_names, list) {
 958                 if (!strcmp(fce->name, name))
 959                         return 1;
 960         }
 961         return 0;
 962 }
 963
 964 static int fw_cache_piggyback_on_request(const char *name)
 965 {
 966         struct firmware_cache *fwc = &fw_cache;
 967         struct fw_cache_entry *fce;
 968         int ret = 0;
 969
 970         spin_lock(&fwc->name_lock);
 971         if (__fw_entry_found(name))
 972                 goto found;
 973
 974         fce = alloc_fw_cache_entry(name);
 975         if (fce) {
 976                 ret = 1;
 977                 list_add(&fce->list, &fwc->fw_names);
 978                 pr_debug("%s: fw: %s\n", __func__, name);
 979         }
 980 found:
 981         spin_unlock(&fwc->name_lock);
 982         return ret;
 983 }
 984
 985 static void free_fw_cache_entry(struct fw_cache_entry *fce)
 986 {
 987         kfree_const(fce->name);
 988         kfree(fce);
 989 }
 990
 991 static void __async_dev_cache_fw_image(void *fw_entry,
 992                                        async_cookie_t cookie)
 993 {
 994         struct fw_cache_entry *fce = fw_entry;
 995         struct firmware_cache *fwc = &fw_cache;
 996         int ret;
 997
 998         ret = cache_firmware(fce->name);
 999         if (ret) {
1000                 spin_lock(&fwc->name_lock);
1001                 list_del(&fce->list);
1002                 spin_unlock(&fwc->name_lock);
1003
1004                 free_fw_cache_entry(fce);
1005         }
1006 }
1007
1008 /* called with dev->devres_lock held */
1009 static void dev_create_fw_entry(struct device *dev, void *res,
1010                                 void *data)
1011 {
1012         struct fw_name_devm *fwn = res;
1013         const char *fw_name = fwn->name;
1014         struct list_head *head = data;
1015         struct fw_cache_entry *fce;
1016
1017         fce = alloc_fw_cache_entry(fw_name);
1018         if (fce)
1019                 list_add(&fce->list, head);
1020 }
1021
1022 static int devm_name_match(struct device *dev, void *res,
1023                            void *match_data)
1024 {
1025         struct fw_name_devm *fwn = res;
1026         return (fwn->magic == (unsigned long)match_data);
1027 }
1028
1029 static void dev_cache_fw_image(struct device *dev, void *data)
1030 {
1031         LIST_HEAD(todo);
1032         struct fw_cache_entry *fce;
1033         struct fw_cache_entry *fce_next;
1034         struct firmware_cache *fwc = &fw_cache;
1035
1036         devres_for_each_res(dev, fw_name_devm_release,
1037                             devm_name_match, &fw_cache,
1038                             dev_create_fw_entry, &todo);
1039
1040         list_for_each_entry_safe(fce, fce_next, &todo, list) {
1041                 list_del(&fce->list);
1042
1043                 spin_lock(&fwc->name_lock);
1044                 /* only one cache entry for one firmware */
1045                 if (!__fw_entry_found(fce->name)) {
1046                         list_add(&fce->list, &fwc->fw_names);
1047                 } else {
1048                         free_fw_cache_entry(fce);
1049                         fce = NULL;
1050                 }
1051                 spin_unlock(&fwc->name_lock);
1052
1053                 if (fce)
1054                         async_schedule_domain(__async_dev_cache_fw_image,
1055                                               (void *)fce,
1056                                               &fw_cache_domain);
1057         }
1058 }
1059
1060 static void __device_uncache_fw_images(void)
1061 {
1062         struct firmware_cache *fwc = &fw_cache;
1063         struct fw_cache_entry *fce;
1064
1065         spin_lock(&fwc->name_lock);
1066         while (!list_empty(&fwc->fw_names)) {
1067                 fce = list_entry(fwc->fw_names.next,
1068                                 struct fw_cache_entry, list);
1069                 list_del(&fce->list);
1070                 spin_unlock(&fwc->name_lock);
1071
1072                 uncache_firmware(fce->name);
1073                 free_fw_cache_entry(fce);
1074
1075                 spin_lock(&fwc->name_lock);
1076         }
1077         spin_unlock(&fwc->name_lock);
1078 }
1079
1080 /**
1081  * device_cache_fw_images() - cache devices' firmware
1082  *
1083  * If one device called request_firmware or its nowait version
1084  * successfully before, the firmware names are recored into the
1085  * device's devres link list, so device_cache_fw_images can call
1086  * cache_firmware() to cache these firmwares for the device,
1087  * then the device driver can load its firmwares easily at
1088  * time when system is not ready to complete loading firmware.
1089  */
1090 static void device_cache_fw_images(void)
1091 {
1092         struct firmware_cache *fwc = &fw_cache;
1093         DEFINE_WAIT(wait);
1094
1095         pr_debug("%s\n", __func__);
1096
1097         /* cancel uncache work */
1098         cancel_delayed_work_sync(&fwc->work);
1099
1100         fw_fallback_set_cache_timeout();
1101
1102         mutex_lock(&fw_lock);
1103         fwc->state = FW_LOADER_START_CACHE;
1104         dpm_for_each_dev(NULL, dev_cache_fw_image);
1105         mutex_unlock(&fw_lock);
1106
1107         /* wait for completion of caching firmware for all devices */
1108         async_synchronize_full_domain(&fw_cache_domain);
1109
1110         fw_fallback_set_default_timeout();
1111 }
1112
1113 /**
1114  * device_uncache_fw_images() - uncache devices' firmware
1115  *
1116  * uncache all firmwares which have been cached successfully
1117  * by device_uncache_fw_images earlier
1118  */
1119 static void device_uncache_fw_images(void)
1120 {
1121         pr_debug("%s\n", __func__);
1122         __device_uncache_fw_images();
1123 }
1124
1125 static void device_uncache_fw_images_work(struct work_struct *work)
1126 {
1127         device_uncache_fw_images();
1128 }
1129
1130 /**
1131  * device_uncache_fw_images_delay() - uncache devices firmwares
1132  * @delay: number of milliseconds to delay uncache device firmwares
1133  *
1134  * uncache all devices's firmwares which has been cached successfully
1135  * by device_cache_fw_images after @delay milliseconds.
1136  */
1137 static void device_uncache_fw_images_delay(unsigned long delay)
1138 {
1139         queue_delayed_work(system_power_efficient_wq, &fw_cache.work,
1140                            msecs_to_jiffies(delay));
1141 }
1142
1143 static int fw_pm_notify(struct notifier_block *notify_block,
1144                         unsigned long mode, void *unused)
1145 {
1146         switch (mode) {
1147         case PM_HIBERNATION_PREPARE:
1148         case PM_SUSPEND_PREPARE:
1149         case PM_RESTORE_PREPARE:
1150                 /*
1151                  * kill pending fallback requests with a custom fallback
1152                  * to avoid stalling suspend.
1153                  */
1154                 kill_pending_fw_fallback_reqs(true);
1155                 device_cache_fw_images();
1156                 break;
1157
1158         case PM_POST_SUSPEND:
1159         case PM_POST_HIBERNATION:
1160         case PM_POST_RESTORE:
1161                 /*
1162                  * In case that system sleep failed and syscore_suspend is
1163                  * not called.
1164                  */
1165                 mutex_lock(&fw_lock);
1166                 fw_cache.state = FW_LOADER_NO_CACHE;
1167                 mutex_unlock(&fw_lock);
1168
1169                 device_uncache_fw_images_delay(10 * MSEC_PER_SEC);
1170                 break;
1171         }
1172
1173         return 0;
1174 }
1175
1176 /* stop caching firmware once syscore_suspend is reached */
1177 static int fw_suspend(void)
1178 {
1179         fw_cache.state = FW_LOADER_NO_CACHE;
1180         return 0;
1181 }
1182
1183 static struct syscore_ops fw_syscore_ops = {
1184         .suspend = fw_suspend,
1185 };
1186
1187 static int __init register_fw_pm_ops(void)
1188 {
1189         int ret;
1190
1191         spin_lock_init(&fw_cache.name_lock);
1192         INIT_LIST_HEAD(&fw_cache.fw_names);
1193
1194         INIT_DELAYED_WORK(&fw_cache.work,
1195                           device_uncache_fw_images_work);
1196
1197         fw_cache.pm_notify.notifier_call = fw_pm_notify;
1198         ret = register_pm_notifier(&fw_cache.pm_notify);
1199         if (ret)
1200                 return ret;
1201
1202         register_syscore_ops(&fw_syscore_ops);
1203
1204         return ret;
1205 }
1206
1207 static inline void unregister_fw_pm_ops(void)
1208 {
1209         unregister_syscore_ops(&fw_syscore_ops);
1210         unregister_pm_notifier(&fw_cache.pm_notify);
1211 }
1212 #else
1213 static int fw_cache_piggyback_on_request(const char *name)
1214 {
1215         return 0;
1216 }
1217 static inline int register_fw_pm_ops(void)
1218 {
1219         return 0;
1220 }
1221 static inline void unregister_fw_pm_ops(void)
1222 {
1223 }
1224 #endif
1225
1226 static void __init fw_cache_init(void)
1227 {
1228         spin_lock_init(&fw_cache.lock);
1229         INIT_LIST_HEAD(&fw_cache.head);
1230         fw_cache.state = FW_LOADER_NO_CACHE;
1231 }
1232
1233 static int fw_shutdown_notify(struct notifier_block *unused1,
1234                               unsigned long unused2, void *unused3)
1235 {
1236         /*
1237          * Kill all pending fallback requests to avoid both stalling shutdown,
1238          * and avoid a deadlock with the usermode_lock.
1239          */
1240         kill_pending_fw_fallback_reqs(false);
1241
1242         return NOTIFY_DONE;
1243 }
1244
1245 static struct notifier_block fw_shutdown_nb = {
1246         .notifier_call = fw_shutdown_notify,
1247 };
1248
1249 static int __init firmware_class_init(void)
1250 {
1251         int ret;
1252
1253         /* No need to unfold these on exit */
1254         fw_cache_init();
1255
1256         ret = register_fw_pm_ops();
1257         if (ret)
1258                 return ret;
1259
1260         ret = register_reboot_notifier(&fw_shutdown_nb);
1261         if (ret)
1262                 goto out;
1263
1264         return register_sysfs_loader();
1265
1266 out:
1267         unregister_fw_pm_ops();
1268         return ret;
1269 }
1270
1271 static void __exit firmware_class_exit(void)
1272 {
1273         unregister_fw_pm_ops();
1274         unregister_reboot_notifier(&fw_shutdown_nb);
1275         unregister_sysfs_loader();
1276 }
1277
1278 fs_initcall(firmware_class_init);
1279 module_exit(firmware_class_exit);