drivers/base/firmware_class.c

   1 /*
   2  * firmware_class.c - Multi purpose firmware loading support
   3  *
   4  * Copyright (c) 2003 Manuel Estrada Sainz
   5  *
   6  * Please see Documentation/firmware_class/ for more information.
   7  *
   8  */
   9
  10 #include <linux/capability.h>
  11 #include <linux/device.h>
  12 #include <linux/module.h>
  13 #include <linux/init.h>
  14 #include <linux/timer.h>
  15 #include <linux/vmalloc.h>
  16 #include <linux/interrupt.h>
  17 #include <linux/bitops.h>
  18 #include <linux/mutex.h>
  19 #include <linux/kthread.h>
  20 #include <linux/highmem.h>
  21 #include <linux/firmware.h>
  22 #include "base.h"
  23
  24 #define to_dev(obj) container_of(obj, struct device, kobj)
  25
  26 MODULE_AUTHOR("Manuel Estrada Sainz");
  27 MODULE_DESCRIPTION("Multi purpose firmware loading support");
  28 MODULE_LICENSE("GPL");
  29
  30 enum {
  31         FW_STATUS_LOADING,
  32         FW_STATUS_DONE,
  33         FW_STATUS_ABORT,
  34 };
  35
  36 static int loading_timeout = 60;        /* In seconds */
  37
  38 /* fw_lock could be moved to 'struct firmware_priv' but since it is just
  39  * guarding for corner cases a global lock should be OK */
  40 static DEFINE_MUTEX(fw_lock);
  41
  42 struct firmware_priv {
  43         char fw_id[FIRMWARE_NAME_MAX];
  44         struct completion completion;
  45         struct bin_attribute attr_data;
  46         struct firmware *fw;
  47         unsigned long status;
  48         struct page **pages;
  49         int nr_pages;
  50         int page_array_size;
  51         const char *vdata;
  52         struct timer_list timeout;
  53 };
  54
  55 #ifdef CONFIG_FW_LOADER
  56 extern struct builtin_fw __start_builtin_fw[];
  57 extern struct builtin_fw __end_builtin_fw[];
  58 #else /* Module case. Avoid ifdefs later; it'll all optimise out */
  59 static struct builtin_fw *__start_builtin_fw;
  60 static struct builtin_fw *__end_builtin_fw;
  61 #endif
  62
  63 static void
  64 fw_load_abort(struct firmware_priv *fw_priv)
  65 {
  66         set_bit(FW_STATUS_ABORT, &fw_priv->status);
  67         wmb();
  68         complete(&fw_priv->completion);
  69 }
  70
  71 static ssize_t
  72 firmware_timeout_show(struct class *class, char *buf)
  73 {
  74         return sprintf(buf, "%d\n", loading_timeout);
  75 }
  76
  77 /**
  78  * firmware_timeout_store - set number of seconds to wait for firmware
  79  * @class: device class pointer
  80  * @buf: buffer to scan for timeout value
  81  * @count: number of bytes in @buf
  82  *
  83  *      Sets the number of seconds to wait for the firmware.  Once
  84  *      this expires an error will be returned to the driver and no
  85  *      firmware will be provided.
  86  *
  87  *      Note: zero means 'wait forever'.
  88  **/
  89 static ssize_t
  90 firmware_timeout_store(struct class *class, const char *buf, size_t count)
  91 {
  92         loading_timeout = simple_strtol(buf, NULL, 10);
  93         if (loading_timeout < 0)
  94                 loading_timeout = 0;
  95         return count;
  96 }
  97
  98 static CLASS_ATTR(timeout, 0644, firmware_timeout_show, firmware_timeout_store);
  99
 100 static void fw_dev_release(struct device *dev);
 101
 102 static int firmware_uevent(struct device *dev, struct kobj_uevent_env *env)
 103 {
 104         struct firmware_priv *fw_priv = dev_get_drvdata(dev);
 105
 106         if (add_uevent_var(env, "FIRMWARE=%s", fw_priv->fw_id))
 107                 return -ENOMEM;
 108         if (add_uevent_var(env, "TIMEOUT=%i", loading_timeout))
 109                 return -ENOMEM;
 110
 111         return 0;
 112 }
 113
 114 static struct class firmware_class = {
 115         .name           = "firmware",
 116         .dev_uevent     = firmware_uevent,
 117         .dev_release    = fw_dev_release,
 118 };
 119
 120 static ssize_t firmware_loading_show(struct device *dev,
 121                                      struct device_attribute *attr, char *buf)
 122 {
 123         struct firmware_priv *fw_priv = dev_get_drvdata(dev);
 124         int loading = test_bit(FW_STATUS_LOADING, &fw_priv->status);
 125         return sprintf(buf, "%d\n", loading);
 126 }
 127
 128 /* Some architectures don't have PAGE_KERNEL_RO */
 129 #ifndef PAGE_KERNEL_RO
 130 #define PAGE_KERNEL_RO PAGE_KERNEL
 131 #endif
 132 /**
 133  * firmware_loading_store - set value in the 'loading' control file
 134  * @dev: device pointer
 135  * @attr: device attribute pointer
 136  * @buf: buffer to scan for loading control value
 137  * @count: number of bytes in @buf
 138  *
 139  *      The relevant values are:
 140  *
 141  *       1: Start a load, discarding any previous partial load.
 142  *       0: Conclude the load and hand the data to the driver code.
 143  *      -1: Conclude the load with an error and discard any written data.
 144  **/
 145 static ssize_t firmware_loading_store(struct device *dev,
 146                                       struct device_attribute *attr,
 147                                       const char *buf, size_t count)
 148 {
 149         struct firmware_priv *fw_priv = dev_get_drvdata(dev);
 150         int loading = simple_strtol(buf, NULL, 10);
 151         int i;
 152
 153         switch (loading) {
 154         case 1:
 155                 mutex_lock(&fw_lock);
 156                 if (!fw_priv->fw) {
 157                         mutex_unlock(&fw_lock);
 158                         break;
 159                 }
 160                 vfree(fw_priv->fw->data);
 161                 fw_priv->fw->data = NULL;
 162                 for (i = 0; i < fw_priv->nr_pages; i++)
 163                         __free_page(fw_priv->pages[i]);
 164                 kfree(fw_priv->pages);
 165                 fw_priv->pages = NULL;
 166                 fw_priv->page_array_size = 0;
 167                 fw_priv->nr_pages = 0;
 168                 fw_priv->fw->size = 0;
 169                 set_bit(FW_STATUS_LOADING, &fw_priv->status);
 170                 mutex_unlock(&fw_lock);
 171                 break;
 172         case 0:
 173                 if (test_bit(FW_STATUS_LOADING, &fw_priv->status)) {
 174                         vfree(fw_priv->fw->data);
 175                         fw_priv->fw->data = vmap(fw_priv->pages,
 176                                                  fw_priv->nr_pages,
 177                                                  0, PAGE_KERNEL_RO);
 178                         if (!fw_priv->fw->data) {
 179                                 dev_err(dev, "%s: vmap() failed\n", __func__);
 180                                 goto err;
 181                         }
 182                         /* Pages will be freed by vfree() */
 183                         fw_priv->pages = NULL;
 184                         fw_priv->page_array_size = 0;
 185                         fw_priv->nr_pages = 0;
 186                         complete(&fw_priv->completion);
 187                         clear_bit(FW_STATUS_LOADING, &fw_priv->status);
 188                         break;
 189                 }
 190                 /* fallthrough */
 191         default:
 192                 dev_err(dev, "%s: unexpected value (%d)\n", __func__, loading);
 193                 /* fallthrough */
 194         case -1:
 195         err:
 196                 fw_load_abort(fw_priv);
 197                 break;
 198         }
 199
 200         return count;
 201 }
 202
 203 static DEVICE_ATTR(loading, 0644, firmware_loading_show, firmware_loading_store);
 204
 205 static ssize_t
 206 firmware_data_read(struct kobject *kobj, struct bin_attribute *bin_attr,
 207                    char *buffer, loff_t offset, size_t count)
 208 {
 209         struct device *dev = to_dev(kobj);
 210         struct firmware_priv *fw_priv = dev_get_drvdata(dev);
 211         struct firmware *fw;
 212         ssize_t ret_count;
 213
 214         mutex_lock(&fw_lock);
 215         fw = fw_priv->fw;
 216         if (!fw || test_bit(FW_STATUS_DONE, &fw_priv->status)) {
 217                 ret_count = -ENODEV;
 218                 goto out;
 219         }
 220         if (offset > fw->size)
 221                 return 0;
 222         if (count > fw->size - offset)
 223                 count = fw->size - offset;
 224
 225         ret_count = count;
 226
 227         while (count) {
 228                 void *page_data;
 229                 int page_nr = offset >> PAGE_SHIFT;
 230                 int page_ofs = offset & (PAGE_SIZE-1);
 231                 int page_cnt = min_t(size_t, PAGE_SIZE - page_ofs, count);
 232
 233                 page_data = kmap(fw_priv->pages[page_nr]);
 234
 235                 memcpy(buffer, page_data + page_ofs, page_cnt);
 236
 237                 kunmap(fw_priv->pages[page_nr]);
 238                 buffer += page_cnt;
 239                 offset += page_cnt;
 240                 count -= page_cnt;
 241         }
 242 out:
 243         mutex_unlock(&fw_lock);
 244         return ret_count;
 245 }
 246
 247 static int
 248 fw_realloc_buffer(struct firmware_priv *fw_priv, int min_size)
 249 {
 250         int pages_needed = ALIGN(min_size, PAGE_SIZE) >> PAGE_SHIFT;
 251
 252         /* If the array of pages is too small, grow it... */
 253         if (fw_priv->page_array_size < pages_needed) {
 254                 int new_array_size = max(pages_needed,
 255                                          fw_priv->page_array_size * 2);
 256                 struct page **new_pages;
 257
 258                 new_pages = kmalloc(new_array_size * sizeof(void *),
 259                                     GFP_KERNEL);
 260                 if (!new_pages) {
 261                         fw_load_abort(fw_priv);
 262                         return -ENOMEM;
 263                 }
 264                 memcpy(new_pages, fw_priv->pages,
 265                        fw_priv->page_array_size * sizeof(void *));
 266                 memset(&new_pages[fw_priv->page_array_size], 0, sizeof(void *) *
 267                        (new_array_size - fw_priv->page_array_size));
 268                 kfree(fw_priv->pages);
 269                 fw_priv->pages = new_pages;
 270                 fw_priv->page_array_size = new_array_size;
 271         }
 272
 273         while (fw_priv->nr_pages < pages_needed) {
 274                 fw_priv->pages[fw_priv->nr_pages] =
 275                         alloc_page(GFP_KERNEL | __GFP_HIGHMEM);
 276
 277                 if (!fw_priv->pages[fw_priv->nr_pages]) {
 278                         fw_load_abort(fw_priv);
 279                         return -ENOMEM;
 280                 }
 281                 fw_priv->nr_pages++;
 282         }
 283         return 0;
 284 }
 285
 286 /**
 287  * firmware_data_write - write method for firmware
 288  * @kobj: kobject for the device
 289  * @bin_attr: bin_attr structure
 290  * @buffer: buffer being written
 291  * @offset: buffer offset for write in total data store area
 292  * @count: buffer size
 293  *
 294  *      Data written to the 'data' attribute will be later handed to
 295  *      the driver as a firmware image.
 296  **/
 297 static ssize_t
 298 firmware_data_write(struct kobject *kobj, struct bin_attribute *bin_attr,
 299                     char *buffer, loff_t offset, size_t count)
 300 {
 301         struct device *dev = to_dev(kobj);
 302         struct firmware_priv *fw_priv = dev_get_drvdata(dev);
 303         struct firmware *fw;
 304         ssize_t retval;
 305
 306         if (!capable(CAP_SYS_RAWIO))
 307                 return -EPERM;
 308
 309         mutex_lock(&fw_lock);
 310         fw = fw_priv->fw;
 311         if (!fw || test_bit(FW_STATUS_DONE, &fw_priv->status)) {
 312                 retval = -ENODEV;
 313                 goto out;
 314         }
 315         retval = fw_realloc_buffer(fw_priv, offset + count);
 316         if (retval)
 317                 goto out;
 318
 319         retval = count;
 320
 321         while (count) {
 322                 void *page_data;
 323                 int page_nr = offset >> PAGE_SHIFT;
 324                 int page_ofs = offset & (PAGE_SIZE - 1);
 325                 int page_cnt = min_t(size_t, PAGE_SIZE - page_ofs, count);
 326
 327                 page_data = kmap(fw_priv->pages[page_nr]);
 328
 329                 memcpy(page_data + page_ofs, buffer, page_cnt);
 330
 331                 kunmap(fw_priv->pages[page_nr]);
 332                 buffer += page_cnt;
 333                 offset += page_cnt;
 334                 count -= page_cnt;
 335         }
 336
 337         fw->size = max_t(size_t, offset, fw->size);
 338 out:
 339         mutex_unlock(&fw_lock);
 340         return retval;
 341 }
 342
 343 static struct bin_attribute firmware_attr_data_tmpl = {
 344         .attr = {.name = "data", .mode = 0644},
 345         .size = 0,
 346         .read = firmware_data_read,
 347         .write = firmware_data_write,
 348 };
 349
 350 static void fw_dev_release(struct device *dev)
 351 {
 352         struct firmware_priv *fw_priv = dev_get_drvdata(dev);
 353         int i;
 354
 355         for (i = 0; i < fw_priv->nr_pages; i++)
 356                 __free_page(fw_priv->pages[i]);
 357         kfree(fw_priv->pages);
 358         kfree(fw_priv);
 359         kfree(dev);
 360
 361         module_put(THIS_MODULE);
 362 }
 363
 364 static void
 365 firmware_class_timeout(u_long data)
 366 {
 367         struct firmware_priv *fw_priv = (struct firmware_priv *) data;
 368         fw_load_abort(fw_priv);
 369 }
 370
 371 static int fw_register_device(struct device **dev_p, const char *fw_name,
 372                               struct device *device)
 373 {
 374         int retval;
 375         struct firmware_priv *fw_priv = kzalloc(sizeof(*fw_priv),
 376                                                 GFP_KERNEL);
 377         struct device *f_dev = kzalloc(sizeof(*f_dev), GFP_KERNEL);
 378
 379         *dev_p = NULL;
 380
 381         if (!fw_priv || !f_dev) {
 382                 dev_err(device, "%s: kmalloc failed\n", __func__);
 383                 retval = -ENOMEM;
 384                 goto error_kfree;
 385         }
 386
 387         init_completion(&fw_priv->completion);
 388         fw_priv->attr_data = firmware_attr_data_tmpl;
 389         strlcpy(fw_priv->fw_id, fw_name, FIRMWARE_NAME_MAX);
 390
 391         fw_priv->timeout.function = firmware_class_timeout;
 392         fw_priv->timeout.data = (u_long) fw_priv;
 393         init_timer(&fw_priv->timeout);
 394
 395         dev_set_name(f_dev, dev_name(device));
 396         f_dev->parent = device;
 397         f_dev->class = &firmware_class;
 398         dev_set_drvdata(f_dev, fw_priv);
 399         dev_set_uevent_suppress(f_dev, 1);
 400         retval = device_register(f_dev);
 401         if (retval) {
 402                 dev_err(device, "%s: device_register failed\n", __func__);
 403                 goto error_kfree;
 404         }
 405         *dev_p = f_dev;
 406         return 0;
 407
 408 error_kfree:
 409         kfree(fw_priv);
 410         kfree(f_dev);
 411         return retval;
 412 }
 413
 414 static int fw_setup_device(struct firmware *fw, struct device **dev_p,
 415                            const char *fw_name, struct device *device,
 416                            int uevent)
 417 {
 418         struct device *f_dev;
 419         struct firmware_priv *fw_priv;
 420         int retval;
 421
 422         *dev_p = NULL;
 423         retval = fw_register_device(&f_dev, fw_name, device);
 424         if (retval)
 425                 goto out;
 426
 427         /* Need to pin this module until class device is destroyed */
 428         __module_get(THIS_MODULE);
 429
 430         fw_priv = dev_get_drvdata(f_dev);
 431
 432         fw_priv->fw = fw;
 433         retval = sysfs_create_bin_file(&f_dev->kobj, &fw_priv->attr_data);
 434         if (retval) {
 435                 dev_err(device, "%s: sysfs_create_bin_file failed\n", __func__);
 436                 goto error_unreg;
 437         }
 438
 439         retval = device_create_file(f_dev, &dev_attr_loading);
 440         if (retval) {
 441                 dev_err(device, "%s: device_create_file failed\n", __func__);
 442                 goto error_unreg;
 443         }
 444
 445         if (uevent)
 446                 dev_set_uevent_suppress(f_dev, 0);
 447         *dev_p = f_dev;
 448         goto out;
 449
 450 error_unreg:
 451         device_unregister(f_dev);
 452 out:
 453         return retval;
 454 }
 455
 456 static int
 457 _request_firmware(const struct firmware **firmware_p, const char *name,
 458                  struct device *device, int uevent)
 459 {
 460         struct device *f_dev;
 461         struct firmware_priv *fw_priv;
 462         struct firmware *firmware;
 463         struct builtin_fw *builtin;
 464         int retval;
 465
 466         if (!firmware_p)
 467                 return -EINVAL;
 468
 469         *firmware_p = firmware = kzalloc(sizeof(*firmware), GFP_KERNEL);
 470         if (!firmware) {
 471                 dev_err(device, "%s: kmalloc(struct firmware) failed\n",
 472                         __func__);
 473                 retval = -ENOMEM;
 474                 goto out;
 475         }
 476
 477         for (builtin = __start_builtin_fw; builtin != __end_builtin_fw;
 478              builtin++) {
 479                 if (strcmp(name, builtin->name))
 480                         continue;
 481                 dev_info(device, "firmware: using built-in firmware %s\n",
 482                          name);
 483                 firmware->size = builtin->size;
 484                 firmware->data = builtin->data;
 485                 return 0;
 486         }
 487
 488         if (uevent)
 489                 dev_info(device, "firmware: requesting %s\n", name);
 490
 491         retval = fw_setup_device(firmware, &f_dev, name, device, uevent);
 492         if (retval)
 493                 goto error_kfree_fw;
 494
 495         fw_priv = dev_get_drvdata(f_dev);
 496
 497         if (uevent) {
 498                 if (loading_timeout > 0) {
 499                         fw_priv->timeout.expires = jiffies + loading_timeout * HZ;
 500                         add_timer(&fw_priv->timeout);
 501                 }
 502
 503                 kobject_uevent(&f_dev->kobj, KOBJ_ADD);
 504                 wait_for_completion(&fw_priv->completion);
 505                 set_bit(FW_STATUS_DONE, &fw_priv->status);
 506                 del_timer_sync(&fw_priv->timeout);
 507         } else
 508                 wait_for_completion(&fw_priv->completion);
 509
 510         mutex_lock(&fw_lock);
 511         if (!fw_priv->fw->size || test_bit(FW_STATUS_ABORT, &fw_priv->status)) {
 512                 retval = -ENOENT;
 513                 release_firmware(fw_priv->fw);
 514                 *firmware_p = NULL;
 515         }
 516         fw_priv->fw = NULL;
 517         mutex_unlock(&fw_lock);
 518         device_unregister(f_dev);
 519         goto out;
 520
 521 error_kfree_fw:
 522         kfree(firmware);
 523         *firmware_p = NULL;
 524 out:
 525         return retval;
 526 }
 527
 528 /**
 529  * request_firmware: - send firmware request and wait for it
 530  * @firmware_p: pointer to firmware image
 531  * @name: name of firmware file
 532  * @device: device for which firmware is being loaded
 533  *
 534  *      @firmware_p will be used to return a firmware image by the name
 535  *      of @name for device @device.
 536  *
 537  *      Should be called from user context where sleeping is allowed.
 538  *
 539  *      @name will be used as $FIRMWARE in the uevent environment and
 540  *      should be distinctive enough not to be confused with any other
 541  *      firmware image for this or any other device.
 542  **/
 543 int
 544 request_firmware(const struct firmware **firmware_p, const char *name,
 545                  struct device *device)
 546 {
 547         int uevent = 1;
 548         return _request_firmware(firmware_p, name, device, uevent);
 549 }
 550
 551 /**
 552  * release_firmware: - release the resource associated with a firmware image
 553  * @fw: firmware resource to release
 554  **/
 555 void
 556 release_firmware(const struct firmware *fw)
 557 {
 558         struct builtin_fw *builtin;
 559
 560         if (fw) {
 561                 for (builtin = __start_builtin_fw; builtin != __end_builtin_fw;
 562                      builtin++) {
 563                         if (fw->data == builtin->data)
 564                                 goto free_fw;
 565                 }
 566                 vfree(fw->data);
 567         free_fw:
 568                 kfree(fw);
 569         }
 570 }
 571
 572 /* Async support */
 573 struct firmware_work {
 574         struct work_struct work;
 575         struct module *module;
 576         const char *name;
 577         struct device *device;
 578         void *context;
 579         void (*cont)(const struct firmware *fw, void *context);
 580         int uevent;
 581 };
 582
 583 static int
 584 request_firmware_work_func(void *arg)
 585 {
 586         struct firmware_work *fw_work = arg;
 587         const struct firmware *fw;
 588         int ret;
 589         if (!arg) {
 590                 WARN_ON(1);
 591                 return 0;
 592         }
 593         ret = _request_firmware(&fw, fw_work->name, fw_work->device,
 594                 fw_work->uevent);
 595         if (ret < 0)
 596                 fw_work->cont(NULL, fw_work->context);
 597         else {
 598                 fw_work->cont(fw, fw_work->context);
 599                 release_firmware(fw);
 600         }
 601         module_put(fw_work->module);
 602         kfree(fw_work);
 603         return ret;
 604 }
 605
 606 /**
 607  * request_firmware_nowait: asynchronous version of request_firmware
 608  * @module: module requesting the firmware
 609  * @uevent: sends uevent to copy the firmware image if this flag
 610  *      is non-zero else the firmware copy must be done manually.
 611  * @name: name of firmware file
 612  * @device: device for which firmware is being loaded
 613  * @context: will be passed over to @cont, and
 614  *      @fw may be %NULL if firmware request fails.
 615  * @cont: function will be called asynchronously when the firmware
 616  *      request is over.
 617  *
 618  *      Asynchronous variant of request_firmware() for contexts where
 619  *      it is not possible to sleep.
 620  **/
 621 int
 622 request_firmware_nowait(
 623         struct module *module, int uevent,
 624         const char *name, struct device *device, void *context,
 625         void (*cont)(const struct firmware *fw, void *context))
 626 {
 627         struct task_struct *task;
 628         struct firmware_work *fw_work = kmalloc(sizeof (struct firmware_work),
 629                                                 GFP_ATOMIC);
 630
 631         if (!fw_work)
 632                 return -ENOMEM;
 633         if (!try_module_get(module)) {
 634                 kfree(fw_work);
 635                 return -EFAULT;
 636         }
 637
 638         *fw_work = (struct firmware_work) {
 639                 .module = module,
 640                 .name = name,
 641                 .device = device,
 642                 .context = context,
 643                 .cont = cont,
 644                 .uevent = uevent,
 645         };
 646
 647         task = kthread_run(request_firmware_work_func, fw_work,
 648                             "firmware/%s", name);
 649
 650         if (IS_ERR(task)) {
 651                 fw_work->cont(NULL, fw_work->context);
 652                 module_put(fw_work->module);
 653                 kfree(fw_work);
 654                 return PTR_ERR(task);
 655         }
 656         return 0;
 657 }
 658
 659 static int __init
 660 firmware_class_init(void)
 661 {
 662         int error;
 663         error = class_register(&firmware_class);
 664         if (error) {
 665                 printk(KERN_ERR "%s: class_register failed\n", __func__);
 666                 return error;
 667         }
 668         error = class_create_file(&firmware_class, &class_attr_timeout);
 669         if (error) {
 670                 printk(KERN_ERR "%s: class_create_file failed\n",
 671                        __func__);
 672                 class_unregister(&firmware_class);
 673         }
 674         return error;
 675
 676 }
 677 static void __exit
 678 firmware_class_exit(void)
 679 {
 680         class_unregister(&firmware_class);
 681 }
 682
 683 fs_initcall(firmware_class_init);
 684 module_exit(firmware_class_exit);
 685
 686 EXPORT_SYMBOL(release_firmware);
 687 EXPORT_SYMBOL(request_firmware);
 688 EXPORT_SYMBOL(request_firmware_nowait);