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