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
  23 #define to_dev(obj) container_of(obj, struct device, kobj)
  24
  25 MODULE_AUTHOR("Manuel Estrada Sainz");
  26 MODULE_DESCRIPTION("Multi purpose firmware loading support");
  27 MODULE_LICENSE("GPL");
  28
  29 enum {
  30         FW_STATUS_LOADING,
  31         FW_STATUS_DONE,
  32         FW_STATUS_ABORT,
  33 };
  34
  35 static int loading_timeout = 60;        /* In seconds */
  36
  37 /* fw_lock could be moved to 'struct firmware_priv' but since it is just
  38  * guarding for corner cases a global lock should be OK */
  39 static DEFINE_MUTEX(fw_lock);
  40
  41 struct firmware_priv {
  42         char *fw_id;
  43         struct completion completion;
  44         struct bin_attribute attr_data;
  45         struct firmware *fw;
  46         unsigned long status;
  47         struct page **pages;
  48         int nr_pages;
  49         int page_array_size;
  50         const char *vdata;
  51         struct timer_list timeout;
  52 };
  53
  54 #ifdef CONFIG_FW_LOADER
  55 extern struct builtin_fw __start_builtin_fw[];
  56 extern struct builtin_fw __end_builtin_fw[];
  57 #else /* Module case. Avoid ifdefs later; it'll all optimise out */
  58 static struct builtin_fw *__start_builtin_fw;
  59 static struct builtin_fw *__end_builtin_fw;
  60 #endif
  61
  62 static void
  63 fw_load_abort(struct firmware_priv *fw_priv)
  64 {
  65         set_bit(FW_STATUS_ABORT, &fw_priv->status);
  66         wmb();
  67         complete(&fw_priv->completion);
  68 }
  69
  70 static ssize_t
  71 firmware_timeout_show(struct class *class,
  72                       struct class_attribute *attr,
  73                       char *buf)
  74 {
  75         return sprintf(buf, "%d\n", loading_timeout);
  76 }
  77
  78 /**
  79  * firmware_timeout_store - set number of seconds to wait for firmware
  80  * @class: device class pointer
  81  * @buf: buffer to scan for timeout value
  82  * @count: number of bytes in @buf
  83  *
  84  *      Sets the number of seconds to wait for the firmware.  Once
  85  *      this expires an error will be returned to the driver and no
  86  *      firmware will be provided.
  87  *
  88  *      Note: zero means 'wait forever'.
  89  **/
  90 static ssize_t
  91 firmware_timeout_store(struct class *class,
  92                         struct class_attribute *attr,
  93                         const char *buf, size_t count)
  94 {
  95         loading_timeout = simple_strtol(buf, NULL, 10);
  96         if (loading_timeout < 0)
  97                 loading_timeout = 0;
  98         return count;
  99 }
 100
 101 static CLASS_ATTR(timeout, 0644, firmware_timeout_show, firmware_timeout_store);
 102
 103 static void fw_dev_release(struct device *dev);
 104
 105 static int firmware_uevent(struct device *dev, struct kobj_uevent_env *env)
 106 {
 107         struct firmware_priv *fw_priv = dev_get_drvdata(dev);
 108
 109         if (add_uevent_var(env, "FIRMWARE=%s", fw_priv->fw_id))
 110                 return -ENOMEM;
 111         if (add_uevent_var(env, "TIMEOUT=%i", loading_timeout))
 112                 return -ENOMEM;
 113
 114         return 0;
 115 }
 116
 117 static struct class firmware_class = {
 118         .name           = "firmware",
 119         .dev_uevent     = firmware_uevent,
 120         .dev_release    = fw_dev_release,
 121 };
 122
 123 static ssize_t firmware_loading_show(struct device *dev,
 124                                      struct device_attribute *attr, char *buf)
 125 {
 126         struct firmware_priv *fw_priv = dev_get_drvdata(dev);
 127         int loading = test_bit(FW_STATUS_LOADING, &fw_priv->status);
 128         return sprintf(buf, "%d\n", loading);
 129 }
 130
 131 /* Some architectures don't have PAGE_KERNEL_RO */
 132 #ifndef PAGE_KERNEL_RO
 133 #define PAGE_KERNEL_RO PAGE_KERNEL
 134 #endif
 135 /**
 136  * firmware_loading_store - set value in the 'loading' control file
 137  * @dev: device pointer
 138  * @attr: device attribute pointer
 139  * @buf: buffer to scan for loading control value
 140  * @count: number of bytes in @buf
 141  *
 142  *      The relevant values are:
 143  *
 144  *       1: Start a load, discarding any previous partial load.
 145  *       0: Conclude the load and hand the data to the driver code.
 146  *      -1: Conclude the load with an error and discard any written data.
 147  **/
 148 static ssize_t firmware_loading_store(struct device *dev,
 149                                       struct device_attribute *attr,
 150                                       const char *buf, size_t count)
 151 {
 152         struct firmware_priv *fw_priv = dev_get_drvdata(dev);
 153         int loading = simple_strtol(buf, NULL, 10);
 154         int i;
 155
 156         switch (loading) {
 157         case 1:
 158                 mutex_lock(&fw_lock);
 159                 if (!fw_priv->fw) {
 160                         mutex_unlock(&fw_lock);
 161                         break;
 162                 }
 163                 vfree(fw_priv->fw->data);
 164                 fw_priv->fw->data = NULL;
 165                 for (i = 0; i < fw_priv->nr_pages; i++)
 166                         __free_page(fw_priv->pages[i]);
 167                 kfree(fw_priv->pages);
 168                 fw_priv->pages = NULL;
 169                 fw_priv->page_array_size = 0;
 170                 fw_priv->nr_pages = 0;
 171                 fw_priv->fw->size = 0;
 172                 set_bit(FW_STATUS_LOADING, &fw_priv->status);
 173                 mutex_unlock(&fw_lock);
 174                 break;
 175         case 0:
 176                 if (test_bit(FW_STATUS_LOADING, &fw_priv->status)) {
 177                         vfree(fw_priv->fw->data);
 178                         fw_priv->fw->data = vmap(fw_priv->pages,
 179                                                  fw_priv->nr_pages,
 180                                                  0, PAGE_KERNEL_RO);
 181                         if (!fw_priv->fw->data) {
 182                                 dev_err(dev, "%s: vmap() failed\n", __func__);
 183                                 goto err;
 184                         }
 185                         /* Pages will be freed by vfree() */
 186                         fw_priv->page_array_size = 0;
 187                         fw_priv->nr_pages = 0;
 188                         complete(&fw_priv->completion);
 189                         clear_bit(FW_STATUS_LOADING, &fw_priv->status);
 190                         break;
 191                 }
 192                 /* fallthrough */
 193         default:
 194                 dev_err(dev, "%s: unexpected value (%d)\n", __func__, loading);
 195                 /* fallthrough */
 196         case -1:
 197         err:
 198                 fw_load_abort(fw_priv);
 199                 break;
 200         }
 201
 202         return count;
 203 }
 204
 205 static DEVICE_ATTR(loading, 0644, firmware_loading_show, firmware_loading_store);
 206
 207 static ssize_t
 208 firmware_data_read(struct kobject *kobj, struct bin_attribute *bin_attr,
 209                    char *buffer, loff_t offset, size_t count)
 210 {
 211         struct device *dev = to_dev(kobj);
 212         struct firmware_priv *fw_priv = dev_get_drvdata(dev);
 213         struct firmware *fw;
 214         ssize_t ret_count;
 215
 216         mutex_lock(&fw_lock);
 217         fw = fw_priv->fw;
 218         if (!fw || test_bit(FW_STATUS_DONE, &fw_priv->status)) {
 219                 ret_count = -ENODEV;
 220                 goto out;
 221         }
 222         if (offset > fw->size) {
 223                 ret_count = 0;
 224                 goto out;
 225         }
 226         if (count > fw->size - offset)
 227                 count = fw->size - offset;
 228
 229         ret_count = count;
 230
 231         while (count) {
 232                 void *page_data;
 233                 int page_nr = offset >> PAGE_SHIFT;
 234                 int page_ofs = offset & (PAGE_SIZE-1);
 235                 int page_cnt = min_t(size_t, PAGE_SIZE - page_ofs, count);
 236
 237                 page_data = kmap(fw_priv->pages[page_nr]);
 238
 239                 memcpy(buffer, page_data + page_ofs, page_cnt);
 240
 241                 kunmap(fw_priv->pages[page_nr]);
 242                 buffer += page_cnt;
 243                 offset += page_cnt;
 244                 count -= page_cnt;
 245         }
 246 out:
 247         mutex_unlock(&fw_lock);
 248         return ret_count;
 249 }
 250
 251 static int
 252 fw_realloc_buffer(struct firmware_priv *fw_priv, int min_size)
 253 {
 254         int pages_needed = ALIGN(min_size, PAGE_SIZE) >> PAGE_SHIFT;
 255
 256         /* If the array of pages is too small, grow it... */
 257         if (fw_priv->page_array_size < pages_needed) {
 258                 int new_array_size = max(pages_needed,
 259                                          fw_priv->page_array_size * 2);
 260                 struct page **new_pages;
 261
 262                 new_pages = kmalloc(new_array_size * sizeof(void *),
 263                                     GFP_KERNEL);
 264                 if (!new_pages) {
 265                         fw_load_abort(fw_priv);
 266                         return -ENOMEM;
 267                 }
 268                 memcpy(new_pages, fw_priv->pages,
 269                        fw_priv->page_array_size * sizeof(void *));
 270                 memset(&new_pages[fw_priv->page_array_size], 0, sizeof(void *) *
 271                        (new_array_size - fw_priv->page_array_size));
 272                 kfree(fw_priv->pages);
 273                 fw_priv->pages = new_pages;
 274                 fw_priv->page_array_size = new_array_size;
 275         }
 276
 277         while (fw_priv->nr_pages < pages_needed) {
 278                 fw_priv->pages[fw_priv->nr_pages] =
 279                         alloc_page(GFP_KERNEL | __GFP_HIGHMEM);
 280
 281                 if (!fw_priv->pages[fw_priv->nr_pages]) {
 282                         fw_load_abort(fw_priv);
 283                         return -ENOMEM;
 284                 }
 285                 fw_priv->nr_pages++;
 286         }
 287         return 0;
 288 }
 289
 290 /**
 291  * firmware_data_write - write method for firmware
 292  * @kobj: kobject for the device
 293  * @bin_attr: bin_attr structure
 294  * @buffer: buffer being written
 295  * @offset: buffer offset for write in total data store area
 296  * @count: buffer size
 297  *
 298  *      Data written to the 'data' attribute will be later handed to
 299  *      the driver as a firmware image.
 300  **/
 301 static ssize_t
 302 firmware_data_write(struct kobject *kobj, struct bin_attribute *bin_attr,
 303                     char *buffer, loff_t offset, size_t count)
 304 {
 305         struct device *dev = to_dev(kobj);
 306         struct firmware_priv *fw_priv = dev_get_drvdata(dev);
 307         struct firmware *fw;
 308         ssize_t retval;
 309
 310         if (!capable(CAP_SYS_RAWIO))
 311                 return -EPERM;
 312
 313         mutex_lock(&fw_lock);
 314         fw = fw_priv->fw;
 315         if (!fw || test_bit(FW_STATUS_DONE, &fw_priv->status)) {
 316                 retval = -ENODEV;
 317                 goto out;
 318         }
 319         retval = fw_realloc_buffer(fw_priv, offset + count);
 320         if (retval)
 321                 goto out;
 322
 323         retval = count;
 324
 325         while (count) {
 326                 void *page_data;
 327                 int page_nr = offset >> PAGE_SHIFT;
 328                 int page_ofs = offset & (PAGE_SIZE - 1);
 329                 int page_cnt = min_t(size_t, PAGE_SIZE - page_ofs, count);
 330
 331                 page_data = kmap(fw_priv->pages[page_nr]);
 332
 333                 memcpy(page_data + page_ofs, buffer, page_cnt);
 334
 335                 kunmap(fw_priv->pages[page_nr]);
 336                 buffer += page_cnt;
 337                 offset += page_cnt;
 338                 count -= page_cnt;
 339         }
 340
 341         fw->size = max_t(size_t, offset, fw->size);
 342 out:
 343         mutex_unlock(&fw_lock);
 344         return retval;
 345 }
 346
 347 static struct bin_attribute firmware_attr_data_tmpl = {
 348         .attr = {.name = "data", .mode = 0644},
 349         .size = 0,
 350         .read = firmware_data_read,
 351         .write = firmware_data_write,
 352 };
 353
 354 static void fw_dev_release(struct device *dev)
 355 {
 356         struct firmware_priv *fw_priv = dev_get_drvdata(dev);
 357         int i;
 358
 359         for (i = 0; i < fw_priv->nr_pages; i++)
 360                 __free_page(fw_priv->pages[i]);
 361         kfree(fw_priv->pages);
 362         kfree(fw_priv->fw_id);
 363         kfree(fw_priv);
 364         kfree(dev);
 365
 366         module_put(THIS_MODULE);
 367 }
 368
 369 static void
 370 firmware_class_timeout(u_long data)
 371 {
 372         struct firmware_priv *fw_priv = (struct firmware_priv *) data;
 373         fw_load_abort(fw_priv);
 374 }
 375
 376 static int fw_register_device(struct device **dev_p, const char *fw_name,
 377                               struct device *device)
 378 {
 379         int retval;
 380         struct firmware_priv *fw_priv = kzalloc(sizeof(*fw_priv),
 381                                                 GFP_KERNEL);
 382         struct device *f_dev = kzalloc(sizeof(*f_dev), GFP_KERNEL);
 383
 384         *dev_p = NULL;
 385
 386         if (!fw_priv || !f_dev) {
 387                 dev_err(device, "%s: kmalloc failed\n", __func__);
 388                 retval = -ENOMEM;
 389                 goto error_kfree;
 390         }
 391
 392         init_completion(&fw_priv->completion);
 393         fw_priv->attr_data = firmware_attr_data_tmpl;
 394         fw_priv->fw_id = kstrdup(fw_name, GFP_KERNEL);
 395         if (!fw_priv->fw_id) {
 396                 dev_err(device, "%s: Firmware name allocation failed\n",
 397                         __func__);
 398                 retval = -ENOMEM;
 399                 goto error_kfree;
 400         }
 401
 402         fw_priv->timeout.function = firmware_class_timeout;
 403         fw_priv->timeout.data = (u_long) fw_priv;
 404         init_timer(&fw_priv->timeout);
 405
 406         dev_set_name(f_dev, "%s", dev_name(device));
 407         f_dev->parent = device;
 408         f_dev->class = &firmware_class;
 409         dev_set_drvdata(f_dev, fw_priv);
 410         dev_set_uevent_suppress(f_dev, 1);
 411         retval = device_register(f_dev);
 412         if (retval) {
 413                 dev_err(device, "%s: device_register failed\n", __func__);
 414                 put_device(f_dev);
 415                 return retval;
 416         }
 417         *dev_p = f_dev;
 418         return 0;
 419
 420 error_kfree:
 421         kfree(f_dev);
 422         kfree(fw_priv);
 423         return retval;
 424 }
 425
 426 static int fw_setup_device(struct firmware *fw, struct device **dev_p,
 427                            const char *fw_name, struct device *device,
 428                            int uevent)
 429 {
 430         struct device *f_dev;
 431         struct firmware_priv *fw_priv;
 432         int retval;
 433
 434         *dev_p = NULL;
 435         retval = fw_register_device(&f_dev, fw_name, device);
 436         if (retval)
 437                 goto out;
 438
 439         /* Need to pin this module until class device is destroyed */
 440         __module_get(THIS_MODULE);
 441
 442         fw_priv = dev_get_drvdata(f_dev);
 443
 444         fw_priv->fw = fw;
 445         retval = sysfs_create_bin_file(&f_dev->kobj, &fw_priv->attr_data);
 446         if (retval) {
 447                 dev_err(device, "%s: sysfs_create_bin_file failed\n", __func__);
 448                 goto error_unreg;
 449         }
 450
 451         retval = device_create_file(f_dev, &dev_attr_loading);
 452         if (retval) {
 453                 dev_err(device, "%s: device_create_file failed\n", __func__);
 454                 goto error_unreg;
 455         }
 456
 457         if (uevent)
 458                 dev_set_uevent_suppress(f_dev, 0);
 459         *dev_p = f_dev;
 460         goto out;
 461
 462 error_unreg:
 463         device_unregister(f_dev);
 464 out:
 465         return retval;
 466 }
 467
 468 static int
 469 _request_firmware(const struct firmware **firmware_p, const char *name,
 470                  struct device *device, int uevent)
 471 {
 472         struct device *f_dev;
 473         struct firmware_priv *fw_priv;
 474         struct firmware *firmware;
 475         struct builtin_fw *builtin;
 476         int retval;
 477
 478         if (!firmware_p)
 479                 return -EINVAL;
 480
 481         *firmware_p = firmware = kzalloc(sizeof(*firmware), GFP_KERNEL);
 482         if (!firmware) {
 483                 dev_err(device, "%s: kmalloc(struct firmware) failed\n",
 484                         __func__);
 485                 retval = -ENOMEM;
 486                 goto out;
 487         }
 488
 489         for (builtin = __start_builtin_fw; builtin != __end_builtin_fw;
 490              builtin++) {
 491                 if (strcmp(name, builtin->name))
 492                         continue;
 493                 dev_info(device, "firmware: using built-in firmware %s\n",
 494                          name);
 495                 firmware->size = builtin->size;
 496                 firmware->data = builtin->data;
 497                 return 0;
 498         }
 499
 500         if (uevent)
 501                 dev_info(device, "firmware: requesting %s\n", name);
 502
 503         retval = fw_setup_device(firmware, &f_dev, name, device, uevent);
 504         if (retval)
 505                 goto error_kfree_fw;
 506
 507         fw_priv = dev_get_drvdata(f_dev);
 508
 509         if (uevent) {
 510                 if (loading_timeout > 0) {
 511                         fw_priv->timeout.expires = jiffies + loading_timeout * HZ;
 512                         add_timer(&fw_priv->timeout);
 513                 }
 514
 515                 kobject_uevent(&f_dev->kobj, KOBJ_ADD);
 516                 wait_for_completion(&fw_priv->completion);
 517                 set_bit(FW_STATUS_DONE, &fw_priv->status);
 518                 del_timer_sync(&fw_priv->timeout);
 519         } else
 520                 wait_for_completion(&fw_priv->completion);
 521
 522         mutex_lock(&fw_lock);
 523         if (!fw_priv->fw->size || test_bit(FW_STATUS_ABORT, &fw_priv->status)) {
 524                 retval = -ENOENT;
 525                 release_firmware(fw_priv->fw);
 526                 *firmware_p = NULL;
 527         }
 528         fw_priv->fw = NULL;
 529         mutex_unlock(&fw_lock);
 530         device_unregister(f_dev);
 531         goto out;
 532
 533 error_kfree_fw:
 534         kfree(firmware);
 535         *firmware_p = NULL;
 536 out:
 537         return retval;
 538 }
 539
 540 /**
 541  * request_firmware: - send firmware request and wait for it
 542  * @firmware_p: pointer to firmware image
 543  * @name: name of firmware file
 544  * @device: device for which firmware is being loaded
 545  *
 546  *      @firmware_p will be used to return a firmware image by the name
 547  *      of @name for device @device.
 548  *
 549  *      Should be called from user context where sleeping is allowed.
 550  *
 551  *      @name will be used as $FIRMWARE in the uevent environment and
 552  *      should be distinctive enough not to be confused with any other
 553  *      firmware image for this or any other device.
 554  **/
 555 int
 556 request_firmware(const struct firmware **firmware_p, const char *name,
 557                  struct device *device)
 558 {
 559         int uevent = 1;
 560         return _request_firmware(firmware_p, name, device, uevent);
 561 }
 562
 563 /**
 564  * release_firmware: - release the resource associated with a firmware image
 565  * @fw: firmware resource to release
 566  **/
 567 void
 568 release_firmware(const struct firmware *fw)
 569 {
 570         struct builtin_fw *builtin;
 571
 572         if (fw) {
 573                 for (builtin = __start_builtin_fw; builtin != __end_builtin_fw;
 574                      builtin++) {
 575                         if (fw->data == builtin->data)
 576                                 goto free_fw;
 577                 }
 578                 vfree(fw->data);
 579         free_fw:
 580                 kfree(fw);
 581         }
 582 }
 583
 584 /* Async support */
 585 struct firmware_work {
 586         struct work_struct work;
 587         struct module *module;
 588         const char *name;
 589         struct device *device;
 590         void *context;
 591         void (*cont)(const struct firmware *fw, void *context);
 592         int uevent;
 593 };
 594
 595 static int
 596 request_firmware_work_func(void *arg)
 597 {
 598         struct firmware_work *fw_work = arg;
 599         const struct firmware *fw;
 600         int ret;
 601         if (!arg) {
 602                 WARN_ON(1);
 603                 return 0;
 604         }
 605         ret = _request_firmware(&fw, fw_work->name, fw_work->device,
 606                 fw_work->uevent);
 607
 608         fw_work->cont(fw, fw_work->context);
 609
 610         module_put(fw_work->module);
 611         kfree(fw_work);
 612         return ret;
 613 }
 614
 615 /**
 616  * request_firmware_nowait - asynchronous version of request_firmware
 617  * @module: module requesting the firmware
 618  * @uevent: sends uevent to copy the firmware image if this flag
 619  *      is non-zero else the firmware copy must be done manually.
 620  * @name: name of firmware file
 621  * @device: device for which firmware is being loaded
 622  * @gfp: allocation flags
 623  * @context: will be passed over to @cont, and
 624  *      @fw may be %NULL if firmware request fails.
 625  * @cont: function will be called asynchronously when the firmware
 626  *      request is over.
 627  *
 628  *      Asynchronous variant of request_firmware() for user contexts where
 629  *      it is not possible to sleep for long time. It can't be called
 630  *      in atomic contexts.
 631  **/
 632 int
 633 request_firmware_nowait(
 634         struct module *module, int uevent,
 635         const char *name, struct device *device, gfp_t gfp, void *context,
 636         void (*cont)(const struct firmware *fw, void *context))
 637 {
 638         struct task_struct *task;
 639         struct firmware_work *fw_work = kmalloc(sizeof (struct firmware_work),
 640                                                 gfp);
 641
 642         if (!fw_work)
 643                 return -ENOMEM;
 644         if (!try_module_get(module)) {
 645                 kfree(fw_work);
 646                 return -EFAULT;
 647         }
 648
 649         *fw_work = (struct firmware_work) {
 650                 .module = module,
 651                 .name = name,
 652                 .device = device,
 653                 .context = context,
 654                 .cont = cont,
 655                 .uevent = uevent,
 656         };
 657
 658         task = kthread_run(request_firmware_work_func, fw_work,
 659                             "firmware/%s", name);
 660
 661         if (IS_ERR(task)) {
 662                 fw_work->cont(NULL, fw_work->context);
 663                 module_put(fw_work->module);
 664                 kfree(fw_work);
 665                 return PTR_ERR(task);
 666         }
 667         return 0;
 668 }
 669
 670 static int __init
 671 firmware_class_init(void)
 672 {
 673         int error;
 674         error = class_register(&firmware_class);
 675         if (error) {
 676                 printk(KERN_ERR "%s: class_register failed\n", __func__);
 677                 return error;
 678         }
 679         error = class_create_file(&firmware_class, &class_attr_timeout);
 680         if (error) {
 681                 printk(KERN_ERR "%s: class_create_file failed\n",
 682                        __func__);
 683                 class_unregister(&firmware_class);
 684         }
 685         return error;
 686
 687 }
 688 static void __exit
 689 firmware_class_exit(void)
 690 {
 691         class_unregister(&firmware_class);
 692 }
 693
 694 fs_initcall(firmware_class_init);
 695 module_exit(firmware_class_exit);
 696
 697 EXPORT_SYMBOL(release_firmware);
 698 EXPORT_SYMBOL(request_firmware);
 699 EXPORT_SYMBOL(request_firmware_nowait);