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;
  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                 ret_count = 0;
 222                 goto out;
 223         }
 224         if (count > fw->size - offset)
 225                 count = fw->size - offset;
 226
 227         ret_count = count;
 228
 229         while (count) {
 230                 void *page_data;
 231                 int page_nr = offset >> PAGE_SHIFT;
 232                 int page_ofs = offset & (PAGE_SIZE-1);
 233                 int page_cnt = min_t(size_t, PAGE_SIZE - page_ofs, count);
 234
 235                 page_data = kmap(fw_priv->pages[page_nr]);
 236
 237                 memcpy(buffer, page_data + page_ofs, page_cnt);
 238
 239                 kunmap(fw_priv->pages[page_nr]);
 240                 buffer += page_cnt;
 241                 offset += page_cnt;
 242                 count -= page_cnt;
 243         }
 244 out:
 245         mutex_unlock(&fw_lock);
 246         return ret_count;
 247 }
 248
 249 static int
 250 fw_realloc_buffer(struct firmware_priv *fw_priv, int min_size)
 251 {
 252         int pages_needed = ALIGN(min_size, PAGE_SIZE) >> PAGE_SHIFT;
 253
 254         /* If the array of pages is too small, grow it... */
 255         if (fw_priv->page_array_size < pages_needed) {
 256                 int new_array_size = max(pages_needed,
 257                                          fw_priv->page_array_size * 2);
 258                 struct page **new_pages;
 259
 260                 new_pages = kmalloc(new_array_size * sizeof(void *),
 261                                     GFP_KERNEL);
 262                 if (!new_pages) {
 263                         fw_load_abort(fw_priv);
 264                         return -ENOMEM;
 265                 }
 266                 memcpy(new_pages, fw_priv->pages,
 267                        fw_priv->page_array_size * sizeof(void *));
 268                 memset(&new_pages[fw_priv->page_array_size], 0, sizeof(void *) *
 269                        (new_array_size - fw_priv->page_array_size));
 270                 kfree(fw_priv->pages);
 271                 fw_priv->pages = new_pages;
 272                 fw_priv->page_array_size = new_array_size;
 273         }
 274
 275         while (fw_priv->nr_pages < pages_needed) {
 276                 fw_priv->pages[fw_priv->nr_pages] =
 277                         alloc_page(GFP_KERNEL | __GFP_HIGHMEM);
 278
 279                 if (!fw_priv->pages[fw_priv->nr_pages]) {
 280                         fw_load_abort(fw_priv);
 281                         return -ENOMEM;
 282                 }
 283                 fw_priv->nr_pages++;
 284         }
 285         return 0;
 286 }
 287
 288 /**
 289  * firmware_data_write - write method for firmware
 290  * @kobj: kobject for the device
 291  * @bin_attr: bin_attr structure
 292  * @buffer: buffer being written
 293  * @offset: buffer offset for write in total data store area
 294  * @count: buffer size
 295  *
 296  *      Data written to the 'data' attribute will be later handed to
 297  *      the driver as a firmware image.
 298  **/
 299 static ssize_t
 300 firmware_data_write(struct kobject *kobj, struct bin_attribute *bin_attr,
 301                     char *buffer, loff_t offset, size_t count)
 302 {
 303         struct device *dev = to_dev(kobj);
 304         struct firmware_priv *fw_priv = dev_get_drvdata(dev);
 305         struct firmware *fw;
 306         ssize_t retval;
 307
 308         if (!capable(CAP_SYS_RAWIO))
 309                 return -EPERM;
 310
 311         mutex_lock(&fw_lock);
 312         fw = fw_priv->fw;
 313         if (!fw || test_bit(FW_STATUS_DONE, &fw_priv->status)) {
 314                 retval = -ENODEV;
 315                 goto out;
 316         }
 317         retval = fw_realloc_buffer(fw_priv, offset + count);
 318         if (retval)
 319                 goto out;
 320
 321         retval = count;
 322
 323         while (count) {
 324                 void *page_data;
 325                 int page_nr = offset >> PAGE_SHIFT;
 326                 int page_ofs = offset & (PAGE_SIZE - 1);
 327                 int page_cnt = min_t(size_t, PAGE_SIZE - page_ofs, count);
 328
 329                 page_data = kmap(fw_priv->pages[page_nr]);
 330
 331                 memcpy(page_data + page_ofs, buffer, page_cnt);
 332
 333                 kunmap(fw_priv->pages[page_nr]);
 334                 buffer += page_cnt;
 335                 offset += page_cnt;
 336                 count -= page_cnt;
 337         }
 338
 339         fw->size = max_t(size_t, offset, fw->size);
 340 out:
 341         mutex_unlock(&fw_lock);
 342         return retval;
 343 }
 344
 345 static struct bin_attribute firmware_attr_data_tmpl = {
 346         .attr = {.name = "data", .mode = 0644},
 347         .size = 0,
 348         .read = firmware_data_read,
 349         .write = firmware_data_write,
 350 };
 351
 352 static void fw_dev_release(struct device *dev)
 353 {
 354         struct firmware_priv *fw_priv = dev_get_drvdata(dev);
 355         int i;
 356
 357         for (i = 0; i < fw_priv->nr_pages; i++)
 358                 __free_page(fw_priv->pages[i]);
 359         kfree(fw_priv->pages);
 360         kfree(fw_priv->fw_id);
 361         kfree(fw_priv);
 362         kfree(dev);
 363
 364         module_put(THIS_MODULE);
 365 }
 366
 367 static void
 368 firmware_class_timeout(u_long data)
 369 {
 370         struct firmware_priv *fw_priv = (struct firmware_priv *) data;
 371         fw_load_abort(fw_priv);
 372 }
 373
 374 static int fw_register_device(struct device **dev_p, const char *fw_name,
 375                               struct device *device)
 376 {
 377         int retval;
 378         struct firmware_priv *fw_priv = kzalloc(sizeof(*fw_priv),
 379                                                 GFP_KERNEL);
 380         struct device *f_dev = kzalloc(sizeof(*f_dev), GFP_KERNEL);
 381
 382         *dev_p = NULL;
 383
 384         if (!fw_priv || !f_dev) {
 385                 dev_err(device, "%s: kmalloc failed\n", __func__);
 386                 retval = -ENOMEM;
 387                 goto error_kfree;
 388         }
 389
 390         init_completion(&fw_priv->completion);
 391         fw_priv->attr_data = firmware_attr_data_tmpl;
 392         fw_priv->fw_id = kstrdup(fw_name, GFP_KERNEL);
 393         if (!fw_priv->fw_id) {
 394                 dev_err(device, "%s: Firmware name allocation failed\n",
 395                         __func__);
 396                 retval = -ENOMEM;
 397                 goto error_kfree;
 398         }
 399
 400         fw_priv->timeout.function = firmware_class_timeout;
 401         fw_priv->timeout.data = (u_long) fw_priv;
 402         init_timer(&fw_priv->timeout);
 403
 404         dev_set_name(f_dev, "%s", dev_name(device));
 405         f_dev->parent = device;
 406         f_dev->class = &firmware_class;
 407         dev_set_drvdata(f_dev, fw_priv);
 408         dev_set_uevent_suppress(f_dev, 1);
 409         retval = device_register(f_dev);
 410         if (retval) {
 411                 dev_err(device, "%s: device_register failed\n", __func__);
 412                 put_device(f_dev);
 413                 return retval;
 414         }
 415         *dev_p = f_dev;
 416         return 0;
 417
 418 error_kfree:
 419         kfree(f_dev);
 420         kfree(fw_priv);
 421         return retval;
 422 }
 423
 424 static int fw_setup_device(struct firmware *fw, struct device **dev_p,
 425                            const char *fw_name, struct device *device,
 426                            int uevent)
 427 {
 428         struct device *f_dev;
 429         struct firmware_priv *fw_priv;
 430         int retval;
 431
 432         *dev_p = NULL;
 433         retval = fw_register_device(&f_dev, fw_name, device);
 434         if (retval)
 435                 goto out;
 436
 437         /* Need to pin this module until class device is destroyed */
 438         __module_get(THIS_MODULE);
 439
 440         fw_priv = dev_get_drvdata(f_dev);
 441
 442         fw_priv->fw = fw;
 443         retval = sysfs_create_bin_file(&f_dev->kobj, &fw_priv->attr_data);
 444         if (retval) {
 445                 dev_err(device, "%s: sysfs_create_bin_file failed\n", __func__);
 446                 goto error_unreg;
 447         }
 448
 449         retval = device_create_file(f_dev, &dev_attr_loading);
 450         if (retval) {
 451                 dev_err(device, "%s: device_create_file failed\n", __func__);
 452                 goto error_unreg;
 453         }
 454
 455         if (uevent)
 456                 dev_set_uevent_suppress(f_dev, 0);
 457         *dev_p = f_dev;
 458         goto out;
 459
 460 error_unreg:
 461         device_unregister(f_dev);
 462 out:
 463         return retval;
 464 }
 465
 466 static int
 467 _request_firmware(const struct firmware **firmware_p, const char *name,
 468                  struct device *device, int uevent)
 469 {
 470         struct device *f_dev;
 471         struct firmware_priv *fw_priv;
 472         struct firmware *firmware;
 473         struct builtin_fw *builtin;
 474         int retval;
 475
 476         if (!firmware_p)
 477                 return -EINVAL;
 478
 479         *firmware_p = firmware = kzalloc(sizeof(*firmware), GFP_KERNEL);
 480         if (!firmware) {
 481                 dev_err(device, "%s: kmalloc(struct firmware) failed\n",
 482                         __func__);
 483                 retval = -ENOMEM;
 484                 goto out;
 485         }
 486
 487         for (builtin = __start_builtin_fw; builtin != __end_builtin_fw;
 488              builtin++) {
 489                 if (strcmp(name, builtin->name))
 490                         continue;
 491                 dev_info(device, "firmware: using built-in firmware %s\n",
 492                          name);
 493                 firmware->size = builtin->size;
 494                 firmware->data = builtin->data;
 495                 return 0;
 496         }
 497
 498         if (uevent)
 499                 dev_info(device, "firmware: requesting %s\n", name);
 500
 501         retval = fw_setup_device(firmware, &f_dev, name, device, uevent);
 502         if (retval)
 503                 goto error_kfree_fw;
 504
 505         fw_priv = dev_get_drvdata(f_dev);
 506
 507         if (uevent) {
 508                 if (loading_timeout > 0) {
 509                         fw_priv->timeout.expires = jiffies + loading_timeout * HZ;
 510                         add_timer(&fw_priv->timeout);
 511                 }
 512
 513                 kobject_uevent(&f_dev->kobj, KOBJ_ADD);
 514                 wait_for_completion(&fw_priv->completion);
 515                 set_bit(FW_STATUS_DONE, &fw_priv->status);
 516                 del_timer_sync(&fw_priv->timeout);
 517         } else
 518                 wait_for_completion(&fw_priv->completion);
 519
 520         mutex_lock(&fw_lock);
 521         if (!fw_priv->fw->size || test_bit(FW_STATUS_ABORT, &fw_priv->status)) {
 522                 retval = -ENOENT;
 523                 release_firmware(fw_priv->fw);
 524                 *firmware_p = NULL;
 525         }
 526         fw_priv->fw = NULL;
 527         mutex_unlock(&fw_lock);
 528         device_unregister(f_dev);
 529         goto out;
 530
 531 error_kfree_fw:
 532         kfree(firmware);
 533         *firmware_p = NULL;
 534 out:
 535         return retval;
 536 }
 537
 538 /**
 539  * request_firmware: - send firmware request and wait for it
 540  * @firmware_p: pointer to firmware image
 541  * @name: name of firmware file
 542  * @device: device for which firmware is being loaded
 543  *
 544  *      @firmware_p will be used to return a firmware image by the name
 545  *      of @name for device @device.
 546  *
 547  *      Should be called from user context where sleeping is allowed.
 548  *
 549  *      @name will be used as $FIRMWARE in the uevent environment and
 550  *      should be distinctive enough not to be confused with any other
 551  *      firmware image for this or any other device.
 552  **/
 553 int
 554 request_firmware(const struct firmware **firmware_p, const char *name,
 555                  struct device *device)
 556 {
 557         int uevent = 1;
 558         return _request_firmware(firmware_p, name, device, uevent);
 559 }
 560
 561 /**
 562  * release_firmware: - release the resource associated with a firmware image
 563  * @fw: firmware resource to release
 564  **/
 565 void
 566 release_firmware(const struct firmware *fw)
 567 {
 568         struct builtin_fw *builtin;
 569
 570         if (fw) {
 571                 for (builtin = __start_builtin_fw; builtin != __end_builtin_fw;
 572                      builtin++) {
 573                         if (fw->data == builtin->data)
 574                                 goto free_fw;
 575                 }
 576                 vfree(fw->data);
 577         free_fw:
 578                 kfree(fw);
 579         }
 580 }
 581
 582 /* Async support */
 583 struct firmware_work {
 584         struct work_struct work;
 585         struct module *module;
 586         const char *name;
 587         struct device *device;
 588         void *context;
 589         void (*cont)(const struct firmware *fw, void *context);
 590         int uevent;
 591 };
 592
 593 static int
 594 request_firmware_work_func(void *arg)
 595 {
 596         struct firmware_work *fw_work = arg;
 597         const struct firmware *fw;
 598         int ret;
 599         if (!arg) {
 600                 WARN_ON(1);
 601                 return 0;
 602         }
 603         ret = _request_firmware(&fw, fw_work->name, fw_work->device,
 604                 fw_work->uevent);
 605         if (ret < 0)
 606                 fw_work->cont(NULL, fw_work->context);
 607         else {
 608                 fw_work->cont(fw, fw_work->context);
 609                 release_firmware(fw);
 610         }
 611         module_put(fw_work->module);
 612         kfree(fw_work);
 613         return ret;
 614 }
 615
 616 /**
 617  * request_firmware_nowait: asynchronous version of request_firmware
 618  * @module: module requesting the firmware
 619  * @uevent: sends uevent to copy the firmware image if this flag
 620  *      is non-zero else the firmware copy must be done manually.
 621  * @name: name of firmware file
 622  * @device: device for which firmware is being loaded
 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, 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_ATOMIC);
 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);