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 bool fw_copy_to_prealloc_buf(struct firmware *fw,
 101                                     void *buf, size_t size)
 102 {
 103         if (!buf)
 104                 return true;
 105         if (size < fw->size)
 106                 return false;
 107         memcpy(buf, fw->data, fw->size);
 108         return true;
 109 }
 110
 111 static bool fw_get_builtin_firmware(struct firmware *fw, const char *name,
 112                                     void *buf, size_t size)
 113 {
 114         struct builtin_fw *b_fw;
 115
 116         for (b_fw = __start_builtin_fw; b_fw != __end_builtin_fw; b_fw++) {
 117                 if (strcmp(name, b_fw->name) == 0) {
 118                         fw->size = b_fw->size;
 119                         fw->data = b_fw->data;
 120                         return fw_copy_to_prealloc_buf(fw, buf, size);
 121                 }
 122         }
 123
 124         return false;
 125 }
 126
 127 static bool fw_is_builtin_firmware(const struct firmware *fw)
 128 {
 129         struct builtin_fw *b_fw;
 130
 131         for (b_fw = __start_builtin_fw; b_fw != __end_builtin_fw; b_fw++)
 132                 if (fw->data == b_fw->data)
 133                         return true;
 134
 135         return false;
 136 }
 137
 138 #else /* Module case - no builtin firmware support */
 139
 140 static inline bool fw_get_builtin_firmware(struct firmware *fw,
 141                                            const char *name, void *buf,
 142                                            size_t size)
 143 {
 144         return false;
 145 }
 146
 147 static inline bool fw_is_builtin_firmware(const struct firmware *fw)
 148 {
 149         return false;
 150 }
 151 #endif
 152
 153 static void fw_state_init(struct fw_priv *fw_priv)
 154 {
 155         struct fw_state *fw_st = &fw_priv->fw_st;
 156
 157         init_completion(&fw_st->completion);
 158         fw_st->status = FW_STATUS_UNKNOWN;
 159 }
 160
 161 static inline int fw_state_wait(struct fw_priv *fw_priv)
 162 {
 163         return __fw_state_wait_common(fw_priv, MAX_SCHEDULE_TIMEOUT);
 164 }
 165
 166 static int fw_cache_piggyback_on_request(const char *name);
 167
 168 static struct fw_priv *__allocate_fw_priv(const char *fw_name,
 169                                           struct firmware_cache *fwc,
 170                                           void *dbuf, size_t size)
 171 {
 172         struct fw_priv *fw_priv;
 173
 174         fw_priv = kzalloc(sizeof(*fw_priv), GFP_ATOMIC);
 175         if (!fw_priv)
 176                 return NULL;
 177
 178         fw_priv->fw_name = kstrdup_const(fw_name, GFP_ATOMIC);
 179         if (!fw_priv->fw_name) {
 180                 kfree(fw_priv);
 181                 return NULL;
 182         }
 183
 184         kref_init(&fw_priv->ref);
 185         fw_priv->fwc = fwc;
 186         fw_priv->data = dbuf;
 187         fw_priv->allocated_size = size;
 188         fw_state_init(fw_priv);
 189 #ifdef CONFIG_FW_LOADER_USER_HELPER
 190         INIT_LIST_HEAD(&fw_priv->pending_list);
 191 #endif
 192
 193         pr_debug("%s: fw-%s fw_priv=%p\n", __func__, fw_name, fw_priv);
 194
 195         return fw_priv;
 196 }
 197
 198 static struct fw_priv *__lookup_fw_priv(const char *fw_name)
 199 {
 200         struct fw_priv *tmp;
 201         struct firmware_cache *fwc = &fw_cache;
 202
 203         list_for_each_entry(tmp, &fwc->head, list)
 204                 if (!strcmp(tmp->fw_name, fw_name))
 205                         return tmp;
 206         return NULL;
 207 }
 208
 209 /* Returns 1 for batching firmware requests with the same name */
 210 static int alloc_lookup_fw_priv(const char *fw_name,
 211                                 struct firmware_cache *fwc,
 212                                 struct fw_priv **fw_priv, void *dbuf,
 213                                 size_t size, enum fw_opt opt_flags)
 214 {
 215         struct fw_priv *tmp;
 216
 217         spin_lock(&fwc->lock);
 218         if (!(opt_flags & FW_OPT_NOCACHE)) {
 219                 tmp = __lookup_fw_priv(fw_name);
 220                 if (tmp) {
 221                         kref_get(&tmp->ref);
 222                         spin_unlock(&fwc->lock);
 223                         *fw_priv = tmp;
 224                         pr_debug("batched request - sharing the same struct fw_priv and lookup for multiple requests\n");
 225                         return 1;
 226                 }
 227         }
 228
 229         tmp = __allocate_fw_priv(fw_name, fwc, dbuf, size);
 230         if (tmp) {
 231                 INIT_LIST_HEAD(&tmp->list);
 232                 if (!(opt_flags & FW_OPT_NOCACHE))
 233                         list_add(&tmp->list, &fwc->head);
 234         }
 235         spin_unlock(&fwc->lock);
 236
 237         *fw_priv = tmp;
 238
 239         return tmp ? 0 : -ENOMEM;
 240 }
 241
 242 static void __free_fw_priv(struct kref *ref)
 243         __releases(&fwc->lock)
 244 {
 245         struct fw_priv *fw_priv = to_fw_priv(ref);
 246         struct firmware_cache *fwc = fw_priv->fwc;
 247
 248         pr_debug("%s: fw-%s fw_priv=%p data=%p size=%u\n",
 249                  __func__, fw_priv->fw_name, fw_priv, fw_priv->data,
 250                  (unsigned int)fw_priv->size);
 251
 252         list_del(&fw_priv->list);
 253         spin_unlock(&fwc->lock);
 254
 255 #ifdef CONFIG_FW_LOADER_USER_HELPER
 256         if (fw_priv->is_paged_buf) {
 257                 int i;
 258                 vunmap(fw_priv->data);
 259                 for (i = 0; i < fw_priv->nr_pages; i++)
 260                         __free_page(fw_priv->pages[i]);
 261                 vfree(fw_priv->pages);
 262         } else
 263 #endif
 264         if (!fw_priv->allocated_size)
 265                 vfree(fw_priv->data);
 266         kfree_const(fw_priv->fw_name);
 267         kfree(fw_priv);
 268 }
 269
 270 static void free_fw_priv(struct fw_priv *fw_priv)
 271 {
 272         struct firmware_cache *fwc = fw_priv->fwc;
 273         spin_lock(&fwc->lock);
 274         if (!kref_put(&fw_priv->ref, __free_fw_priv))
 275                 spin_unlock(&fwc->lock);
 276 }
 277
 278 /* direct firmware loading support */
 279 static char fw_path_para[256];
 280 static const char * const fw_path[] = {
 281         fw_path_para,
 282         "/lib/firmware/updates/" UTS_RELEASE,
 283         "/lib/firmware/updates",
 284         "/lib/firmware/" UTS_RELEASE,
 285         "/lib/firmware"
 286 };
 287
 288 /*
 289  * Typical usage is that passing 'firmware_class.path=$CUSTOMIZED_PATH'
 290  * from kernel command line because firmware_class is generally built in
 291  * kernel instead of module.
 292  */
 293 module_param_string(path, fw_path_para, sizeof(fw_path_para), 0644);
 294 MODULE_PARM_DESC(path, "customized firmware image search path with a higher priority than default path");
 295
 296 static int
 297 fw_get_filesystem_firmware(struct device *device, struct fw_priv *fw_priv)
 298 {
 299         loff_t size;
 300         int i, len;
 301         int rc = -ENOENT;
 302         char *path;
 303         enum kernel_read_file_id id = READING_FIRMWARE;
 304         size_t msize = INT_MAX;
 305
 306         /* Already populated data member means we're loading into a buffer */
 307         if (fw_priv->data) {
 308                 id = READING_FIRMWARE_PREALLOC_BUFFER;
 309                 msize = fw_priv->allocated_size;
 310         }
 311
 312         path = __getname();
 313         if (!path)
 314                 return -ENOMEM;
 315
 316         for (i = 0; i < ARRAY_SIZE(fw_path); i++) {
 317                 /* skip the unset customized path */
 318                 if (!fw_path[i][0])
 319                         continue;
 320
 321                 len = snprintf(path, PATH_MAX, "%s/%s",
 322                                fw_path[i], fw_priv->fw_name);
 323                 if (len >= PATH_MAX) {
 324                         rc = -ENAMETOOLONG;
 325                         break;
 326                 }
 327
 328                 fw_priv->size = 0;
 329                 rc = kernel_read_file_from_path(path, &fw_priv->data, &size,
 330                                                 msize, id);
 331                 if (rc) {
 332                         if (rc == -ENOENT)
 333                                 dev_dbg(device, "loading %s failed with error %d\n",
 334                                          path, rc);
 335                         else
 336                                 dev_warn(device, "loading %s failed with error %d\n",
 337                                          path, rc);
 338                         continue;
 339                 }
 340                 dev_dbg(device, "direct-loading %s\n", fw_priv->fw_name);
 341                 fw_priv->size = size;
 342                 fw_state_done(fw_priv);
 343                 break;
 344         }
 345         __putname(path);
 346
 347         return rc;
 348 }
 349
 350 /* firmware holds the ownership of pages */
 351 static void firmware_free_data(const struct firmware *fw)
 352 {
 353         /* Loaded directly? */
 354         if (!fw->priv) {
 355                 vfree(fw->data);
 356                 return;
 357         }
 358         free_fw_priv(fw->priv);
 359 }
 360
 361 /* store the pages buffer info firmware from buf */
 362 static void fw_set_page_data(struct fw_priv *fw_priv, struct firmware *fw)
 363 {
 364         fw->priv = fw_priv;
 365 #ifdef CONFIG_FW_LOADER_USER_HELPER
 366         fw->pages = fw_priv->pages;
 367 #endif
 368         fw->size = fw_priv->size;
 369         fw->data = fw_priv->data;
 370
 371         pr_debug("%s: fw-%s fw_priv=%p data=%p size=%u\n",
 372                  __func__, fw_priv->fw_name, fw_priv, fw_priv->data,
 373                  (unsigned int)fw_priv->size);
 374 }
 375
 376 #ifdef CONFIG_PM_SLEEP
 377 static void fw_name_devm_release(struct device *dev, void *res)
 378 {
 379         struct fw_name_devm *fwn = res;
 380
 381         if (fwn->magic == (unsigned long)&fw_cache)
 382                 pr_debug("%s: fw_name-%s devm-%p released\n",
 383                                 __func__, fwn->name, res);
 384         kfree_const(fwn->name);
 385 }
 386
 387 static int fw_devm_match(struct device *dev, void *res,
 388                 void *match_data)
 389 {
 390         struct fw_name_devm *fwn = res;
 391
 392         return (fwn->magic == (unsigned long)&fw_cache) &&
 393                 !strcmp(fwn->name, match_data);
 394 }
 395
 396 static struct fw_name_devm *fw_find_devm_name(struct device *dev,
 397                 const char *name)
 398 {
 399         struct fw_name_devm *fwn;
 400
 401         fwn = devres_find(dev, fw_name_devm_release,
 402                           fw_devm_match, (void *)name);
 403         return fwn;
 404 }
 405
 406 static bool fw_cache_is_setup(struct device *dev, const char *name)
 407 {
 408         struct fw_name_devm *fwn;
 409
 410         fwn = fw_find_devm_name(dev, name);
 411         if (fwn)
 412                 return true;
 413
 414         return false;
 415 }
 416
 417 /* add firmware name into devres list */
 418 static int fw_add_devm_name(struct device *dev, const char *name)
 419 {
 420         struct fw_name_devm *fwn;
 421
 422         if (fw_cache_is_setup(dev, name))
 423                 return 0;
 424
 425         fwn = devres_alloc(fw_name_devm_release, sizeof(struct fw_name_devm),
 426                            GFP_KERNEL);
 427         if (!fwn)
 428                 return -ENOMEM;
 429         fwn->name = kstrdup_const(name, GFP_KERNEL);
 430         if (!fwn->name) {
 431                 devres_free(fwn);
 432                 return -ENOMEM;
 433         }
 434
 435         fwn->magic = (unsigned long)&fw_cache;
 436         devres_add(dev, fwn);
 437
 438         return 0;
 439 }
 440 #else
 441 static bool fw_cache_is_setup(struct device *dev, const char *name)
 442 {
 443         return false;
 444 }
 445
 446 static int fw_add_devm_name(struct device *dev, const char *name)
 447 {
 448         return 0;
 449 }
 450 #endif
 451
 452 int assign_fw(struct firmware *fw, struct device *device,
 453               enum fw_opt opt_flags)
 454 {
 455         struct fw_priv *fw_priv = fw->priv;
 456         int ret;
 457
 458         mutex_lock(&fw_lock);
 459         if (!fw_priv->size || fw_state_is_aborted(fw_priv)) {
 460                 mutex_unlock(&fw_lock);
 461                 return -ENOENT;
 462         }
 463
 464         /*
 465          * add firmware name into devres list so that we can auto cache
 466          * and uncache firmware for device.
 467          *
 468          * device may has been deleted already, but the problem
 469          * should be fixed in devres or driver core.
 470          */
 471         /* don't cache firmware handled without uevent */
 472         if (device && (opt_flags & FW_OPT_UEVENT) &&
 473             !(opt_flags & FW_OPT_NOCACHE)) {
 474                 ret = fw_add_devm_name(device, fw_priv->fw_name);
 475                 if (ret) {
 476                         mutex_unlock(&fw_lock);
 477                         return ret;
 478                 }
 479         }
 480
 481         /*
 482          * After caching firmware image is started, let it piggyback
 483          * on request firmware.
 484          */
 485         if (!(opt_flags & FW_OPT_NOCACHE) &&
 486             fw_priv->fwc->state == FW_LOADER_START_CACHE) {
 487                 if (fw_cache_piggyback_on_request(fw_priv->fw_name))
 488                         kref_get(&fw_priv->ref);
 489         }
 490
 491         /* pass the pages buffer to driver at the last minute */
 492         fw_set_page_data(fw_priv, fw);
 493         mutex_unlock(&fw_lock);
 494         return 0;
 495 }
 496
 497 /* prepare firmware and firmware_buf structs;
 498  * return 0 if a firmware is already assigned, 1 if need to load one,
 499  * or a negative error code
 500  */
 501 static int
 502 _request_firmware_prepare(struct firmware **firmware_p, const char *name,
 503                           struct device *device, void *dbuf, size_t size,
 504                           enum fw_opt opt_flags)
 505 {
 506         struct firmware *firmware;
 507         struct fw_priv *fw_priv;
 508         int ret;
 509
 510         *firmware_p = firmware = kzalloc(sizeof(*firmware), GFP_KERNEL);
 511         if (!firmware) {
 512                 dev_err(device, "%s: kmalloc(struct firmware) failed\n",
 513                         __func__);
 514                 return -ENOMEM;
 515         }
 516
 517         if (fw_get_builtin_firmware(firmware, name, dbuf, size)) {
 518                 dev_dbg(device, "using built-in %s\n", name);
 519                 return 0; /* assigned */
 520         }
 521
 522         ret = alloc_lookup_fw_priv(name, &fw_cache, &fw_priv, dbuf, size,
 523                                   opt_flags);
 524
 525         /*
 526          * bind with 'priv' now to avoid warning in failure path
 527          * of requesting firmware.
 528          */
 529         firmware->priv = fw_priv;
 530
 531         if (ret > 0) {
 532                 ret = fw_state_wait(fw_priv);
 533                 if (!ret) {
 534                         fw_set_page_data(fw_priv, firmware);
 535                         return 0; /* assigned */
 536                 }
 537         }
 538
 539         if (ret < 0)
 540                 return ret;
 541         return 1; /* need to load */
 542 }
 543
 544 /*
 545  * Batched requests need only one wake, we need to do this step last due to the
 546  * fallback mechanism. The buf is protected with kref_get(), and it won't be
 547  * released until the last user calls release_firmware().
 548  *
 549  * Failed batched requests are possible as well, in such cases we just share
 550  * the struct fw_priv and won't release it until all requests are woken
 551  * and have gone through this same path.
 552  */
 553 static void fw_abort_batch_reqs(struct firmware *fw)
 554 {
 555         struct fw_priv *fw_priv;
 556
 557         /* Loaded directly? */
 558         if (!fw || !fw->priv)
 559                 return;
 560
 561         fw_priv = fw->priv;
 562         mutex_lock(&fw_lock);
 563         if (!fw_state_is_aborted(fw_priv))
 564                 fw_state_aborted(fw_priv);
 565         mutex_unlock(&fw_lock);
 566 }
 567
 568 /* called from request_firmware() and request_firmware_work_func() */
 569 static int
 570 _request_firmware(const struct firmware **firmware_p, const char *name,
 571                   struct device *device, void *buf, size_t size,
 572                   enum fw_opt opt_flags)
 573 {
 574         struct firmware *fw = NULL;
 575         int ret;
 576
 577         if (!firmware_p)
 578                 return -EINVAL;
 579
 580         if (!name || name[0] == '\0') {
 581                 ret = -EINVAL;
 582                 goto out;
 583         }
 584
 585         ret = _request_firmware_prepare(&fw, name, device, buf, size,
 586                                         opt_flags);
 587         if (ret <= 0) /* error or already assigned */
 588                 goto out;
 589
 590         ret = fw_get_filesystem_firmware(device, fw->priv);
 591         if (ret) {
 592                 if (!(opt_flags & FW_OPT_NO_WARN))
 593                         dev_warn(device,
 594                                  "Direct firmware load for %s failed with error %d\n",
 595                                  name, ret);
 596                 ret = firmware_fallback_sysfs(fw, name, device, opt_flags, ret);
 597         } else
 598                 ret = assign_fw(fw, device, opt_flags);
 599
 600  out:
 601         if (ret < 0) {
 602                 fw_abort_batch_reqs(fw);
 603                 release_firmware(fw);
 604                 fw = NULL;
 605         }
 606
 607         *firmware_p = fw;
 608         return ret;
 609 }
 610
 611 /**
 612  * request_firmware() - send firmware request and wait for it
 613  * @firmware_p: pointer to firmware image
 614  * @name: name of firmware file
 615  * @device: device for which firmware is being loaded
 616  *
 617  *      @firmware_p will be used to return a firmware image by the name
 618  *      of @name for device @device.
 619  *
 620  *      Should be called from user context where sleeping is allowed.
 621  *
 622  *      @name will be used as $FIRMWARE in the uevent environment and
 623  *      should be distinctive enough not to be confused with any other
 624  *      firmware image for this or any other device.
 625  *
 626  *      Caller must hold the reference count of @device.
 627  *
 628  *      The function can be called safely inside device's suspend and
 629  *      resume callback.
 630  **/
 631 int
 632 request_firmware(const struct firmware **firmware_p, const char *name,
 633                  struct device *device)
 634 {
 635         int ret;
 636
 637         /* Need to pin this module until return */
 638         __module_get(THIS_MODULE);
 639         ret = _request_firmware(firmware_p, name, device, NULL, 0,
 640                                 FW_OPT_UEVENT);
 641         module_put(THIS_MODULE);
 642         return ret;
 643 }
 644 EXPORT_SYMBOL(request_firmware);
 645
 646 /**
 647  * firmware_request_nowarn() - request for an optional fw module
 648  * @firmware: pointer to firmware image
 649  * @name: name of firmware file
 650  * @device: device for which firmware is being loaded
 651  *
 652  * This function is similar in behaviour to request_firmware(), except
 653  * it doesn't produce warning messages when the file is not found.
 654  * The sysfs fallback mechanism is enabled if direct filesystem lookup fails,
 655  * however, however failures to find the firmware file with it are still
 656  * suppressed. It is therefore up to the driver to check for the return value
 657  * of this call and to decide when to inform the users of errors.
 658  **/
 659 int firmware_request_nowarn(const struct firmware **firmware, const char *name,
 660                             struct device *device)
 661 {
 662         int ret;
 663
 664         /* Need to pin this module until return */
 665         __module_get(THIS_MODULE);
 666         ret = _request_firmware(firmware, name, device, NULL, 0,
 667                                 FW_OPT_UEVENT | FW_OPT_NO_WARN);
 668         module_put(THIS_MODULE);
 669         return ret;
 670 }
 671 EXPORT_SYMBOL_GPL(firmware_request_nowarn);
 672
 673 /**
 674  * request_firmware_direct() - load firmware directly without usermode helper
 675  * @firmware_p: pointer to firmware image
 676  * @name: name of firmware file
 677  * @device: device for which firmware is being loaded
 678  *
 679  * This function works pretty much like request_firmware(), but this doesn't
 680  * fall back to usermode helper even if the firmware couldn't be loaded
 681  * directly from fs.  Hence it's useful for loading optional firmwares, which
 682  * aren't always present, without extra long timeouts of udev.
 683  **/
 684 int request_firmware_direct(const struct firmware **firmware_p,
 685                             const char *name, struct device *device)
 686 {
 687         int ret;
 688
 689         __module_get(THIS_MODULE);
 690         ret = _request_firmware(firmware_p, name, device, NULL, 0,
 691                                 FW_OPT_UEVENT | FW_OPT_NO_WARN |
 692                                 FW_OPT_NOFALLBACK);
 693         module_put(THIS_MODULE);
 694         return ret;
 695 }
 696 EXPORT_SYMBOL_GPL(request_firmware_direct);
 697
 698 /**
 699  * firmware_request_cache() - cache firmware for suspend so resume can use it
 700  * @name: name of firmware file
 701  * @device: device for which firmware should be cached for
 702  *
 703  * There are some devices with an optimization that enables the device to not
 704  * require loading firmware on system reboot. This optimization may still
 705  * require the firmware present on resume from suspend. This routine can be
 706  * used to ensure the firmware is present on resume from suspend in these
 707  * situations. This helper is not compatible with drivers which use
 708  * request_firmware_into_buf() or request_firmware_nowait() with no uevent set.
 709  **/
 710 int firmware_request_cache(struct device *device, const char *name)
 711 {
 712         int ret;
 713
 714         mutex_lock(&fw_lock);
 715         ret = fw_add_devm_name(device, name);
 716         mutex_unlock(&fw_lock);
 717
 718         return ret;
 719 }
 720 EXPORT_SYMBOL_GPL(firmware_request_cache);
 721
 722 /**
 723  * request_firmware_into_buf() - load firmware into a previously allocated buffer
 724  * @firmware_p: pointer to firmware image
 725  * @name: name of firmware file
 726  * @device: device for which firmware is being loaded and DMA region allocated
 727  * @buf: address of buffer to load firmware into
 728  * @size: size of buffer
 729  *
 730  * This function works pretty much like request_firmware(), but it doesn't
 731  * allocate a buffer to hold the firmware data. Instead, the firmware
 732  * is loaded directly into the buffer pointed to by @buf and the @firmware_p
 733  * data member is pointed at @buf.
 734  *
 735  * This function doesn't cache firmware either.
 736  */
 737 int
 738 request_firmware_into_buf(const struct firmware **firmware_p, const char *name,
 739                           struct device *device, void *buf, size_t size)
 740 {
 741         int ret;
 742
 743         if (fw_cache_is_setup(device, name))
 744                 return -EOPNOTSUPP;
 745
 746         __module_get(THIS_MODULE);
 747         ret = _request_firmware(firmware_p, name, device, buf, size,
 748                                 FW_OPT_UEVENT | FW_OPT_NOCACHE);
 749         module_put(THIS_MODULE);
 750         return ret;
 751 }
 752 EXPORT_SYMBOL(request_firmware_into_buf);
 753
 754 /**
 755  * release_firmware() - release the resource associated with a firmware image
 756  * @fw: firmware resource to release
 757  **/
 758 void release_firmware(const struct firmware *fw)
 759 {
 760         if (fw) {
 761                 if (!fw_is_builtin_firmware(fw))
 762                         firmware_free_data(fw);
 763                 kfree(fw);
 764         }
 765 }
 766 EXPORT_SYMBOL(release_firmware);
 767
 768 /* Async support */
 769 struct firmware_work {
 770         struct work_struct work;
 771         struct module *module;
 772         const char *name;
 773         struct device *device;
 774         void *context;
 775         void (*cont)(const struct firmware *fw, void *context);
 776         enum fw_opt opt_flags;
 777 };
 778
 779 static void request_firmware_work_func(struct work_struct *work)
 780 {
 781         struct firmware_work *fw_work;
 782         const struct firmware *fw;
 783
 784         fw_work = container_of(work, struct firmware_work, work);
 785
 786         _request_firmware(&fw, fw_work->name, fw_work->device, NULL, 0,
 787                           fw_work->opt_flags);
 788         fw_work->cont(fw, fw_work->context);
 789         put_device(fw_work->device); /* taken in request_firmware_nowait() */
 790
 791         module_put(fw_work->module);
 792         kfree_const(fw_work->name);
 793         kfree(fw_work);
 794 }
 795
 796 /**
 797  * request_firmware_nowait() - asynchronous version of request_firmware
 798  * @module: module requesting the firmware
 799  * @uevent: sends uevent to copy the firmware image if this flag
 800  *      is non-zero else the firmware copy must be done manually.
 801  * @name: name of firmware file
 802  * @device: device for which firmware is being loaded
 803  * @gfp: allocation flags
 804  * @context: will be passed over to @cont, and
 805  *      @fw may be %NULL if firmware request fails.
 806  * @cont: function will be called asynchronously when the firmware
 807  *      request is over.
 808  *
 809  *      Caller must hold the reference count of @device.
 810  *
 811  *      Asynchronous variant of request_firmware() for user contexts:
 812  *              - sleep for as small periods as possible since it may
 813  *                increase kernel boot time of built-in device drivers
 814  *                requesting firmware in their ->probe() methods, if
 815  *                @gfp is GFP_KERNEL.
 816  *
 817  *              - can't sleep at all if @gfp is GFP_ATOMIC.
 818  **/
 819 int
 820 request_firmware_nowait(
 821         struct module *module, bool uevent,
 822         const char *name, struct device *device, gfp_t gfp, void *context,
 823         void (*cont)(const struct firmware *fw, void *context))
 824 {
 825         struct firmware_work *fw_work;
 826
 827         fw_work = kzalloc(sizeof(struct firmware_work), gfp);
 828         if (!fw_work)
 829                 return -ENOMEM;
 830
 831         fw_work->module = module;
 832         fw_work->name = kstrdup_const(name, gfp);
 833         if (!fw_work->name) {
 834                 kfree(fw_work);
 835                 return -ENOMEM;
 836         }
 837         fw_work->device = device;
 838         fw_work->context = context;
 839         fw_work->cont = cont;
 840         fw_work->opt_flags = FW_OPT_NOWAIT |
 841                 (uevent ? FW_OPT_UEVENT : FW_OPT_USERHELPER);
 842
 843         if (!uevent && fw_cache_is_setup(device, name)) {
 844                 kfree_const(fw_work->name);
 845                 kfree(fw_work);
 846                 return -EOPNOTSUPP;
 847         }
 848
 849         if (!try_module_get(module)) {
 850                 kfree_const(fw_work->name);
 851                 kfree(fw_work);
 852                 return -EFAULT;
 853         }
 854
 855         get_device(fw_work->device);
 856         INIT_WORK(&fw_work->work, request_firmware_work_func);
 857         schedule_work(&fw_work->work);
 858         return 0;
 859 }
 860 EXPORT_SYMBOL(request_firmware_nowait);
 861
 862 #ifdef CONFIG_PM_SLEEP
 863 static ASYNC_DOMAIN_EXCLUSIVE(fw_cache_domain);
 864
 865 /**
 866  * cache_firmware() - cache one firmware image in kernel memory space
 867  * @fw_name: the firmware image name
 868  *
 869  * Cache firmware in kernel memory so that drivers can use it when
 870  * system isn't ready for them to request firmware image from userspace.
 871  * Once it returns successfully, driver can use request_firmware or its
 872  * nowait version to get the cached firmware without any interacting
 873  * with userspace
 874  *
 875  * Return 0 if the firmware image has been cached successfully
 876  * Return !0 otherwise
 877  *
 878  */
 879 static int cache_firmware(const char *fw_name)
 880 {
 881         int ret;
 882         const struct firmware *fw;
 883
 884         pr_debug("%s: %s\n", __func__, fw_name);
 885
 886         ret = request_firmware(&fw, fw_name, NULL);
 887         if (!ret)
 888                 kfree(fw);
 889
 890         pr_debug("%s: %s ret=%d\n", __func__, fw_name, ret);
 891
 892         return ret;
 893 }
 894
 895 static struct fw_priv *lookup_fw_priv(const char *fw_name)
 896 {
 897         struct fw_priv *tmp;
 898         struct firmware_cache *fwc = &fw_cache;
 899
 900         spin_lock(&fwc->lock);
 901         tmp = __lookup_fw_priv(fw_name);
 902         spin_unlock(&fwc->lock);
 903
 904         return tmp;
 905 }
 906
 907 /**
 908  * uncache_firmware() - remove one cached firmware image
 909  * @fw_name: the firmware image name
 910  *
 911  * Uncache one firmware image which has been cached successfully
 912  * before.
 913  *
 914  * Return 0 if the firmware cache has been removed successfully
 915  * Return !0 otherwise
 916  *
 917  */
 918 static int uncache_firmware(const char *fw_name)
 919 {
 920         struct fw_priv *fw_priv;
 921         struct firmware fw;
 922
 923         pr_debug("%s: %s\n", __func__, fw_name);
 924
 925         if (fw_get_builtin_firmware(&fw, fw_name, NULL, 0))
 926                 return 0;
 927
 928         fw_priv = lookup_fw_priv(fw_name);
 929         if (fw_priv) {
 930                 free_fw_priv(fw_priv);
 931                 return 0;
 932         }
 933
 934         return -EINVAL;
 935 }
 936
 937 static struct fw_cache_entry *alloc_fw_cache_entry(const char *name)
 938 {
 939         struct fw_cache_entry *fce;
 940
 941         fce = kzalloc(sizeof(*fce), GFP_ATOMIC);
 942         if (!fce)
 943                 goto exit;
 944
 945         fce->name = kstrdup_const(name, GFP_ATOMIC);
 946         if (!fce->name) {
 947                 kfree(fce);
 948                 fce = NULL;
 949                 goto exit;
 950         }
 951 exit:
 952         return fce;
 953 }
 954
 955 static int __fw_entry_found(const char *name)
 956 {
 957         struct firmware_cache *fwc = &fw_cache;
 958         struct fw_cache_entry *fce;
 959
 960         list_for_each_entry(fce, &fwc->fw_names, list) {
 961                 if (!strcmp(fce->name, name))
 962                         return 1;
 963         }
 964         return 0;
 965 }
 966
 967 static int fw_cache_piggyback_on_request(const char *name)
 968 {
 969         struct firmware_cache *fwc = &fw_cache;
 970         struct fw_cache_entry *fce;
 971         int ret = 0;
 972
 973         spin_lock(&fwc->name_lock);
 974         if (__fw_entry_found(name))
 975                 goto found;
 976
 977         fce = alloc_fw_cache_entry(name);
 978         if (fce) {
 979                 ret = 1;
 980                 list_add(&fce->list, &fwc->fw_names);
 981                 pr_debug("%s: fw: %s\n", __func__, name);
 982         }
 983 found:
 984         spin_unlock(&fwc->name_lock);
 985         return ret;
 986 }
 987
 988 static void free_fw_cache_entry(struct fw_cache_entry *fce)
 989 {
 990         kfree_const(fce->name);
 991         kfree(fce);
 992 }
 993
 994 static void __async_dev_cache_fw_image(void *fw_entry,
 995                                        async_cookie_t cookie)
 996 {
 997         struct fw_cache_entry *fce = fw_entry;
 998         struct firmware_cache *fwc = &fw_cache;
 999         int ret;
1000
1001         ret = cache_firmware(fce->name);
1002         if (ret) {
1003                 spin_lock(&fwc->name_lock);
1004                 list_del(&fce->list);
1005                 spin_unlock(&fwc->name_lock);
1006
1007                 free_fw_cache_entry(fce);
1008         }
1009 }
1010
1011 /* called with dev->devres_lock held */
1012 static void dev_create_fw_entry(struct device *dev, void *res,
1013                                 void *data)
1014 {
1015         struct fw_name_devm *fwn = res;
1016         const char *fw_name = fwn->name;
1017         struct list_head *head = data;
1018         struct fw_cache_entry *fce;
1019
1020         fce = alloc_fw_cache_entry(fw_name);
1021         if (fce)
1022                 list_add(&fce->list, head);
1023 }
1024
1025 static int devm_name_match(struct device *dev, void *res,
1026                            void *match_data)
1027 {
1028         struct fw_name_devm *fwn = res;
1029         return (fwn->magic == (unsigned long)match_data);
1030 }
1031
1032 static void dev_cache_fw_image(struct device *dev, void *data)
1033 {
1034         LIST_HEAD(todo);
1035         struct fw_cache_entry *fce;
1036         struct fw_cache_entry *fce_next;
1037         struct firmware_cache *fwc = &fw_cache;
1038
1039         devres_for_each_res(dev, fw_name_devm_release,
1040                             devm_name_match, &fw_cache,
1041                             dev_create_fw_entry, &todo);
1042
1043         list_for_each_entry_safe(fce, fce_next, &todo, list) {
1044                 list_del(&fce->list);
1045
1046                 spin_lock(&fwc->name_lock);
1047                 /* only one cache entry for one firmware */
1048                 if (!__fw_entry_found(fce->name)) {
1049                         list_add(&fce->list, &fwc->fw_names);
1050                 } else {
1051                         free_fw_cache_entry(fce);
1052                         fce = NULL;
1053                 }
1054                 spin_unlock(&fwc->name_lock);
1055
1056                 if (fce)
1057                         async_schedule_domain(__async_dev_cache_fw_image,
1058                                               (void *)fce,
1059                                               &fw_cache_domain);
1060         }
1061 }
1062
1063 static void __device_uncache_fw_images(void)
1064 {
1065         struct firmware_cache *fwc = &fw_cache;
1066         struct fw_cache_entry *fce;
1067
1068         spin_lock(&fwc->name_lock);
1069         while (!list_empty(&fwc->fw_names)) {
1070                 fce = list_entry(fwc->fw_names.next,
1071                                 struct fw_cache_entry, list);
1072                 list_del(&fce->list);
1073                 spin_unlock(&fwc->name_lock);
1074
1075                 uncache_firmware(fce->name);
1076                 free_fw_cache_entry(fce);
1077
1078                 spin_lock(&fwc->name_lock);
1079         }
1080         spin_unlock(&fwc->name_lock);
1081 }
1082
1083 /**
1084  * device_cache_fw_images() - cache devices' firmware
1085  *
1086  * If one device called request_firmware or its nowait version
1087  * successfully before, the firmware names are recored into the
1088  * device's devres link list, so device_cache_fw_images can call
1089  * cache_firmware() to cache these firmwares for the device,
1090  * then the device driver can load its firmwares easily at
1091  * time when system is not ready to complete loading firmware.
1092  */
1093 static void device_cache_fw_images(void)
1094 {
1095         struct firmware_cache *fwc = &fw_cache;
1096         DEFINE_WAIT(wait);
1097
1098         pr_debug("%s\n", __func__);
1099
1100         /* cancel uncache work */
1101         cancel_delayed_work_sync(&fwc->work);
1102
1103         fw_fallback_set_cache_timeout();
1104
1105         mutex_lock(&fw_lock);
1106         fwc->state = FW_LOADER_START_CACHE;
1107         dpm_for_each_dev(NULL, dev_cache_fw_image);
1108         mutex_unlock(&fw_lock);
1109
1110         /* wait for completion of caching firmware for all devices */
1111         async_synchronize_full_domain(&fw_cache_domain);
1112
1113         fw_fallback_set_default_timeout();
1114 }
1115
1116 /**
1117  * device_uncache_fw_images() - uncache devices' firmware
1118  *
1119  * uncache all firmwares which have been cached successfully
1120  * by device_uncache_fw_images earlier
1121  */
1122 static void device_uncache_fw_images(void)
1123 {
1124         pr_debug("%s\n", __func__);
1125         __device_uncache_fw_images();
1126 }
1127
1128 static void device_uncache_fw_images_work(struct work_struct *work)
1129 {
1130         device_uncache_fw_images();
1131 }
1132
1133 /**
1134  * device_uncache_fw_images_delay() - uncache devices firmwares
1135  * @delay: number of milliseconds to delay uncache device firmwares
1136  *
1137  * uncache all devices's firmwares which has been cached successfully
1138  * by device_cache_fw_images after @delay milliseconds.
1139  */
1140 static void device_uncache_fw_images_delay(unsigned long delay)
1141 {
1142         queue_delayed_work(system_power_efficient_wq, &fw_cache.work,
1143                            msecs_to_jiffies(delay));
1144 }
1145
1146 static int fw_pm_notify(struct notifier_block *notify_block,
1147                         unsigned long mode, void *unused)
1148 {
1149         switch (mode) {
1150         case PM_HIBERNATION_PREPARE:
1151         case PM_SUSPEND_PREPARE:
1152         case PM_RESTORE_PREPARE:
1153                 /*
1154                  * kill pending fallback requests with a custom fallback
1155                  * to avoid stalling suspend.
1156                  */
1157                 kill_pending_fw_fallback_reqs(true);
1158                 device_cache_fw_images();
1159                 break;
1160
1161         case PM_POST_SUSPEND:
1162         case PM_POST_HIBERNATION:
1163         case PM_POST_RESTORE:
1164                 /*
1165                  * In case that system sleep failed and syscore_suspend is
1166                  * not called.
1167                  */
1168                 mutex_lock(&fw_lock);
1169                 fw_cache.state = FW_LOADER_NO_CACHE;
1170                 mutex_unlock(&fw_lock);
1171
1172                 device_uncache_fw_images_delay(10 * MSEC_PER_SEC);
1173                 break;
1174         }
1175
1176         return 0;
1177 }
1178
1179 /* stop caching firmware once syscore_suspend is reached */
1180 static int fw_suspend(void)
1181 {
1182         fw_cache.state = FW_LOADER_NO_CACHE;
1183         return 0;
1184 }
1185
1186 static struct syscore_ops fw_syscore_ops = {
1187         .suspend = fw_suspend,
1188 };
1189
1190 static int __init register_fw_pm_ops(void)
1191 {
1192         int ret;
1193
1194         spin_lock_init(&fw_cache.name_lock);
1195         INIT_LIST_HEAD(&fw_cache.fw_names);
1196
1197         INIT_DELAYED_WORK(&fw_cache.work,
1198                           device_uncache_fw_images_work);
1199
1200         fw_cache.pm_notify.notifier_call = fw_pm_notify;
1201         ret = register_pm_notifier(&fw_cache.pm_notify);
1202         if (ret)
1203                 return ret;
1204
1205         register_syscore_ops(&fw_syscore_ops);
1206
1207         return ret;
1208 }
1209
1210 static inline void unregister_fw_pm_ops(void)
1211 {
1212         unregister_syscore_ops(&fw_syscore_ops);
1213         unregister_pm_notifier(&fw_cache.pm_notify);
1214 }
1215 #else
1216 static int fw_cache_piggyback_on_request(const char *name)
1217 {
1218         return 0;
1219 }
1220 static inline int register_fw_pm_ops(void)
1221 {
1222         return 0;
1223 }
1224 static inline void unregister_fw_pm_ops(void)
1225 {
1226 }
1227 #endif
1228
1229 static void __init fw_cache_init(void)
1230 {
1231         spin_lock_init(&fw_cache.lock);
1232         INIT_LIST_HEAD(&fw_cache.head);
1233         fw_cache.state = FW_LOADER_NO_CACHE;
1234 }
1235
1236 static int fw_shutdown_notify(struct notifier_block *unused1,
1237                               unsigned long unused2, void *unused3)
1238 {
1239         /*
1240          * Kill all pending fallback requests to avoid both stalling shutdown,
1241          * and avoid a deadlock with the usermode_lock.
1242          */
1243         kill_pending_fw_fallback_reqs(false);
1244
1245         return NOTIFY_DONE;
1246 }
1247
1248 static struct notifier_block fw_shutdown_nb = {
1249         .notifier_call = fw_shutdown_notify,
1250 };
1251
1252 static int __init firmware_class_init(void)
1253 {
1254         int ret;
1255
1256         /* No need to unfold these on exit */
1257         fw_cache_init();
1258
1259         ret = register_fw_pm_ops();
1260         if (ret)
1261                 return ret;
1262
1263         ret = register_reboot_notifier(&fw_shutdown_nb);
1264         if (ret)
1265                 goto out;
1266
1267         return register_sysfs_loader();
1268
1269 out:
1270         unregister_fw_pm_ops();
1271         return ret;
1272 }
1273
1274 static void __exit firmware_class_exit(void)
1275 {
1276         unregister_fw_pm_ops();
1277         unregister_reboot_notifier(&fw_shutdown_nb);
1278         unregister_sysfs_loader();
1279 }
1280
1281 fs_initcall(firmware_class_init);
1282 module_exit(firmware_class_exit);