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
  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         int alloc_size;
  49         struct timer_list timeout;
  50 };
  51
  52 #ifdef CONFIG_FW_LOADER
  53 extern struct builtin_fw __start_builtin_fw[];
  54 extern struct builtin_fw __end_builtin_fw[];
  55 #else /* Module case. Avoid ifdefs later; it'll all optimise out */
  56 static struct builtin_fw *__start_builtin_fw;
  57 static struct builtin_fw *__end_builtin_fw;
  58 #endif
  59
  60 static void
  61 fw_load_abort(struct firmware_priv *fw_priv)
  62 {
  63         set_bit(FW_STATUS_ABORT, &fw_priv->status);
  64         wmb();
  65         complete(&fw_priv->completion);
  66 }
  67
  68 static ssize_t
  69 firmware_timeout_show(struct class *class, char *buf)
  70 {
  71         return sprintf(buf, "%d\n", loading_timeout);
  72 }
  73
  74 /**
  75  * firmware_timeout_store - set number of seconds to wait for firmware
  76  * @class: device class pointer
  77  * @buf: buffer to scan for timeout value
  78  * @count: number of bytes in @buf
  79  *
  80  *      Sets the number of seconds to wait for the firmware.  Once
  81  *      this expires an error will be returned to the driver and no
  82  *      firmware will be provided.
  83  *
  84  *      Note: zero means 'wait forever'.
  85  **/
  86 static ssize_t
  87 firmware_timeout_store(struct class *class, const char *buf, size_t count)
  88 {
  89         loading_timeout = simple_strtol(buf, NULL, 10);
  90         if (loading_timeout < 0)
  91                 loading_timeout = 0;
  92         return count;
  93 }
  94
  95 static CLASS_ATTR(timeout, 0644, firmware_timeout_show, firmware_timeout_store);
  96
  97 static void fw_dev_release(struct device *dev);
  98
  99 static int firmware_uevent(struct device *dev, struct kobj_uevent_env *env)
 100 {
 101         struct firmware_priv *fw_priv = dev_get_drvdata(dev);
 102
 103         if (add_uevent_var(env, "FIRMWARE=%s", fw_priv->fw_id))
 104                 return -ENOMEM;
 105         if (add_uevent_var(env, "TIMEOUT=%i", loading_timeout))
 106                 return -ENOMEM;
 107
 108         return 0;
 109 }
 110
 111 static struct class firmware_class = {
 112         .name           = "firmware",
 113         .dev_uevent     = firmware_uevent,
 114         .dev_release    = fw_dev_release,
 115 };
 116
 117 static ssize_t firmware_loading_show(struct device *dev,
 118                                      struct device_attribute *attr, char *buf)
 119 {
 120         struct firmware_priv *fw_priv = dev_get_drvdata(dev);
 121         int loading = test_bit(FW_STATUS_LOADING, &fw_priv->status);
 122         return sprintf(buf, "%d\n", loading);
 123 }
 124
 125 /**
 126  * firmware_loading_store - set value in the 'loading' control file
 127  * @dev: device pointer
 128  * @attr: device attribute pointer
 129  * @buf: buffer to scan for loading control value
 130  * @count: number of bytes in @buf
 131  *
 132  *      The relevant values are:
 133  *
 134  *       1: Start a load, discarding any previous partial load.
 135  *       0: Conclude the load and hand the data to the driver code.
 136  *      -1: Conclude the load with an error and discard any written data.
 137  **/
 138 static ssize_t firmware_loading_store(struct device *dev,
 139                                       struct device_attribute *attr,
 140                                       const char *buf, size_t count)
 141 {
 142         struct firmware_priv *fw_priv = dev_get_drvdata(dev);
 143         int loading = simple_strtol(buf, NULL, 10);
 144
 145         switch (loading) {
 146         case 1:
 147                 mutex_lock(&fw_lock);
 148                 if (!fw_priv->fw) {
 149                         mutex_unlock(&fw_lock);
 150                         break;
 151                 }
 152                 vfree(fw_priv->fw->data);
 153                 fw_priv->fw->data = NULL;
 154                 fw_priv->fw->size = 0;
 155                 fw_priv->alloc_size = 0;
 156                 set_bit(FW_STATUS_LOADING, &fw_priv->status);
 157                 mutex_unlock(&fw_lock);
 158                 break;
 159         case 0:
 160                 if (test_bit(FW_STATUS_LOADING, &fw_priv->status)) {
 161                         complete(&fw_priv->completion);
 162                         clear_bit(FW_STATUS_LOADING, &fw_priv->status);
 163                         break;
 164                 }
 165                 /* fallthrough */
 166         default:
 167                 dev_err(dev, "%s: unexpected value (%d)\n", __func__, loading);
 168                 /* fallthrough */
 169         case -1:
 170                 fw_load_abort(fw_priv);
 171                 break;
 172         }
 173
 174         return count;
 175 }
 176
 177 static DEVICE_ATTR(loading, 0644, firmware_loading_show, firmware_loading_store);
 178
 179 static ssize_t
 180 firmware_data_read(struct kobject *kobj, struct bin_attribute *bin_attr,
 181                    char *buffer, loff_t offset, size_t count)
 182 {
 183         struct device *dev = to_dev(kobj);
 184         struct firmware_priv *fw_priv = dev_get_drvdata(dev);
 185         struct firmware *fw;
 186         ssize_t ret_count;
 187
 188         mutex_lock(&fw_lock);
 189         fw = fw_priv->fw;
 190         if (!fw || test_bit(FW_STATUS_DONE, &fw_priv->status)) {
 191                 ret_count = -ENODEV;
 192                 goto out;
 193         }
 194         ret_count = memory_read_from_buffer(buffer, count, &offset,
 195                                                 fw->data, fw->size);
 196 out:
 197         mutex_unlock(&fw_lock);
 198         return ret_count;
 199 }
 200
 201 static int
 202 fw_realloc_buffer(struct firmware_priv *fw_priv, int min_size)
 203 {
 204         u8 *new_data;
 205         int new_size = fw_priv->alloc_size;
 206
 207         if (min_size <= fw_priv->alloc_size)
 208                 return 0;
 209
 210         new_size = ALIGN(min_size, PAGE_SIZE);
 211         new_data = vmalloc(new_size);
 212         if (!new_data) {
 213                 printk(KERN_ERR "%s: unable to alloc buffer\n", __func__);
 214                 /* Make sure that we don't keep incomplete data */
 215                 fw_load_abort(fw_priv);
 216                 return -ENOMEM;
 217         }
 218         fw_priv->alloc_size = new_size;
 219         if (fw_priv->fw->data) {
 220                 memcpy(new_data, fw_priv->fw->data, fw_priv->fw->size);
 221                 vfree(fw_priv->fw->data);
 222         }
 223         fw_priv->fw->data = new_data;
 224         BUG_ON(min_size > fw_priv->alloc_size);
 225         return 0;
 226 }
 227
 228 /**
 229  * firmware_data_write - write method for firmware
 230  * @kobj: kobject for the device
 231  * @bin_attr: bin_attr structure
 232  * @buffer: buffer being written
 233  * @offset: buffer offset for write in total data store area
 234  * @count: buffer size
 235  *
 236  *      Data written to the 'data' attribute will be later handed to
 237  *      the driver as a firmware image.
 238  **/
 239 static ssize_t
 240 firmware_data_write(struct kobject *kobj, struct bin_attribute *bin_attr,
 241                     char *buffer, loff_t offset, size_t count)
 242 {
 243         struct device *dev = to_dev(kobj);
 244         struct firmware_priv *fw_priv = dev_get_drvdata(dev);
 245         struct firmware *fw;
 246         ssize_t retval;
 247
 248         if (!capable(CAP_SYS_RAWIO))
 249                 return -EPERM;
 250
 251         mutex_lock(&fw_lock);
 252         fw = fw_priv->fw;
 253         if (!fw || test_bit(FW_STATUS_DONE, &fw_priv->status)) {
 254                 retval = -ENODEV;
 255                 goto out;
 256         }
 257         retval = fw_realloc_buffer(fw_priv, offset + count);
 258         if (retval)
 259                 goto out;
 260
 261         memcpy((u8 *)fw->data + offset, buffer, count);
 262
 263         fw->size = max_t(size_t, offset + count, fw->size);
 264         retval = count;
 265 out:
 266         mutex_unlock(&fw_lock);
 267         return retval;
 268 }
 269
 270 static struct bin_attribute firmware_attr_data_tmpl = {
 271         .attr = {.name = "data", .mode = 0644},
 272         .size = 0,
 273         .read = firmware_data_read,
 274         .write = firmware_data_write,
 275 };
 276
 277 static void fw_dev_release(struct device *dev)
 278 {
 279         struct firmware_priv *fw_priv = dev_get_drvdata(dev);
 280
 281         kfree(fw_priv);
 282         kfree(dev);
 283
 284         module_put(THIS_MODULE);
 285 }
 286
 287 static void
 288 firmware_class_timeout(u_long data)
 289 {
 290         struct firmware_priv *fw_priv = (struct firmware_priv *) data;
 291         fw_load_abort(fw_priv);
 292 }
 293
 294 static int fw_register_device(struct device **dev_p, const char *fw_name,
 295                               struct device *device)
 296 {
 297         int retval;
 298         struct firmware_priv *fw_priv = kzalloc(sizeof(*fw_priv),
 299                                                 GFP_KERNEL);
 300         struct device *f_dev = kzalloc(sizeof(*f_dev), GFP_KERNEL);
 301
 302         *dev_p = NULL;
 303
 304         if (!fw_priv || !f_dev) {
 305                 dev_err(device, "%s: kmalloc failed\n", __func__);
 306                 retval = -ENOMEM;
 307                 goto error_kfree;
 308         }
 309
 310         init_completion(&fw_priv->completion);
 311         fw_priv->attr_data = firmware_attr_data_tmpl;
 312         strlcpy(fw_priv->fw_id, fw_name, FIRMWARE_NAME_MAX);
 313
 314         fw_priv->timeout.function = firmware_class_timeout;
 315         fw_priv->timeout.data = (u_long) fw_priv;
 316         init_timer(&fw_priv->timeout);
 317
 318         dev_set_name(f_dev, dev_name(device));
 319         f_dev->parent = device;
 320         f_dev->class = &firmware_class;
 321         dev_set_drvdata(f_dev, fw_priv);
 322         dev_set_uevent_suppress(f_dev, 1);
 323         retval = device_register(f_dev);
 324         if (retval) {
 325                 dev_err(device, "%s: device_register failed\n", __func__);
 326                 goto error_kfree;
 327         }
 328         *dev_p = f_dev;
 329         return 0;
 330
 331 error_kfree:
 332         kfree(fw_priv);
 333         kfree(f_dev);
 334         return retval;
 335 }
 336
 337 static int fw_setup_device(struct firmware *fw, struct device **dev_p,
 338                            const char *fw_name, struct device *device,
 339                            int uevent)
 340 {
 341         struct device *f_dev;
 342         struct firmware_priv *fw_priv;
 343         int retval;
 344
 345         *dev_p = NULL;
 346         retval = fw_register_device(&f_dev, fw_name, device);
 347         if (retval)
 348                 goto out;
 349
 350         /* Need to pin this module until class device is destroyed */
 351         __module_get(THIS_MODULE);
 352
 353         fw_priv = dev_get_drvdata(f_dev);
 354
 355         fw_priv->fw = fw;
 356         retval = sysfs_create_bin_file(&f_dev->kobj, &fw_priv->attr_data);
 357         if (retval) {
 358                 dev_err(device, "%s: sysfs_create_bin_file failed\n", __func__);
 359                 goto error_unreg;
 360         }
 361
 362         retval = device_create_file(f_dev, &dev_attr_loading);
 363         if (retval) {
 364                 dev_err(device, "%s: device_create_file failed\n", __func__);
 365                 goto error_unreg;
 366         }
 367
 368         if (uevent)
 369                 dev_set_uevent_suppress(f_dev, 0);
 370         *dev_p = f_dev;
 371         goto out;
 372
 373 error_unreg:
 374         device_unregister(f_dev);
 375 out:
 376         return retval;
 377 }
 378
 379 static int
 380 _request_firmware(const struct firmware **firmware_p, const char *name,
 381                  struct device *device, int uevent)
 382 {
 383         struct device *f_dev;
 384         struct firmware_priv *fw_priv;
 385         struct firmware *firmware;
 386         struct builtin_fw *builtin;
 387         int retval;
 388
 389         if (!firmware_p)
 390                 return -EINVAL;
 391
 392         *firmware_p = firmware = kzalloc(sizeof(*firmware), GFP_KERNEL);
 393         if (!firmware) {
 394                 dev_err(device, "%s: kmalloc(struct firmware) failed\n",
 395                         __func__);
 396                 retval = -ENOMEM;
 397                 goto out;
 398         }
 399
 400         for (builtin = __start_builtin_fw; builtin != __end_builtin_fw;
 401              builtin++) {
 402                 if (strcmp(name, builtin->name))
 403                         continue;
 404                 dev_info(device, "firmware: using built-in firmware %s\n",
 405                          name);
 406                 firmware->size = builtin->size;
 407                 firmware->data = builtin->data;
 408                 return 0;
 409         }
 410
 411         if (uevent)
 412                 dev_info(device, "firmware: requesting %s\n", name);
 413
 414         retval = fw_setup_device(firmware, &f_dev, name, device, uevent);
 415         if (retval)
 416                 goto error_kfree_fw;
 417
 418         fw_priv = dev_get_drvdata(f_dev);
 419
 420         if (uevent) {
 421                 if (loading_timeout > 0) {
 422                         fw_priv->timeout.expires = jiffies + loading_timeout * HZ;
 423                         add_timer(&fw_priv->timeout);
 424                 }
 425
 426                 kobject_uevent(&f_dev->kobj, KOBJ_ADD);
 427                 wait_for_completion(&fw_priv->completion);
 428                 set_bit(FW_STATUS_DONE, &fw_priv->status);
 429                 del_timer_sync(&fw_priv->timeout);
 430         } else
 431                 wait_for_completion(&fw_priv->completion);
 432
 433         mutex_lock(&fw_lock);
 434         if (!fw_priv->fw->size || test_bit(FW_STATUS_ABORT, &fw_priv->status)) {
 435                 retval = -ENOENT;
 436                 release_firmware(fw_priv->fw);
 437                 *firmware_p = NULL;
 438         }
 439         fw_priv->fw = NULL;
 440         mutex_unlock(&fw_lock);
 441         device_unregister(f_dev);
 442         goto out;
 443
 444 error_kfree_fw:
 445         kfree(firmware);
 446         *firmware_p = NULL;
 447 out:
 448         return retval;
 449 }
 450
 451 /**
 452  * request_firmware: - send firmware request and wait for it
 453  * @firmware_p: pointer to firmware image
 454  * @name: name of firmware file
 455  * @device: device for which firmware is being loaded
 456  *
 457  *      @firmware_p will be used to return a firmware image by the name
 458  *      of @name for device @device.
 459  *
 460  *      Should be called from user context where sleeping is allowed.
 461  *
 462  *      @name will be used as $FIRMWARE in the uevent environment and
 463  *      should be distinctive enough not to be confused with any other
 464  *      firmware image for this or any other device.
 465  **/
 466 int
 467 request_firmware(const struct firmware **firmware_p, const char *name,
 468                  struct device *device)
 469 {
 470         int uevent = 1;
 471         return _request_firmware(firmware_p, name, device, uevent);
 472 }
 473
 474 /**
 475  * release_firmware: - release the resource associated with a firmware image
 476  * @fw: firmware resource to release
 477  **/
 478 void
 479 release_firmware(const struct firmware *fw)
 480 {
 481         struct builtin_fw *builtin;
 482
 483         if (fw) {
 484                 for (builtin = __start_builtin_fw; builtin != __end_builtin_fw;
 485                      builtin++) {
 486                         if (fw->data == builtin->data)
 487                                 goto free_fw;
 488                 }
 489                 vfree(fw->data);
 490         free_fw:
 491                 kfree(fw);
 492         }
 493 }
 494
 495 /* Async support */
 496 struct firmware_work {
 497         struct work_struct work;
 498         struct module *module;
 499         const char *name;
 500         struct device *device;
 501         void *context;
 502         void (*cont)(const struct firmware *fw, void *context);
 503         int uevent;
 504 };
 505
 506 static int
 507 request_firmware_work_func(void *arg)
 508 {
 509         struct firmware_work *fw_work = arg;
 510         const struct firmware *fw;
 511         int ret;
 512         if (!arg) {
 513                 WARN_ON(1);
 514                 return 0;
 515         }
 516         ret = _request_firmware(&fw, fw_work->name, fw_work->device,
 517                 fw_work->uevent);
 518         if (ret < 0)
 519                 fw_work->cont(NULL, fw_work->context);
 520         else {
 521                 fw_work->cont(fw, fw_work->context);
 522                 release_firmware(fw);
 523         }
 524         module_put(fw_work->module);
 525         kfree(fw_work);
 526         return ret;
 527 }
 528
 529 /**
 530  * request_firmware_nowait: asynchronous version of request_firmware
 531  * @module: module requesting the firmware
 532  * @uevent: sends uevent to copy the firmware image if this flag
 533  *      is non-zero else the firmware copy must be done manually.
 534  * @name: name of firmware file
 535  * @device: device for which firmware is being loaded
 536  * @context: will be passed over to @cont, and
 537  *      @fw may be %NULL if firmware request fails.
 538  * @cont: function will be called asynchronously when the firmware
 539  *      request is over.
 540  *
 541  *      Asynchronous variant of request_firmware() for contexts where
 542  *      it is not possible to sleep.
 543  **/
 544 int
 545 request_firmware_nowait(
 546         struct module *module, int uevent,
 547         const char *name, struct device *device, void *context,
 548         void (*cont)(const struct firmware *fw, void *context))
 549 {
 550         struct task_struct *task;
 551         struct firmware_work *fw_work = kmalloc(sizeof (struct firmware_work),
 552                                                 GFP_ATOMIC);
 553
 554         if (!fw_work)
 555                 return -ENOMEM;
 556         if (!try_module_get(module)) {
 557                 kfree(fw_work);
 558                 return -EFAULT;
 559         }
 560
 561         *fw_work = (struct firmware_work) {
 562                 .module = module,
 563                 .name = name,
 564                 .device = device,
 565                 .context = context,
 566                 .cont = cont,
 567                 .uevent = uevent,
 568         };
 569
 570         task = kthread_run(request_firmware_work_func, fw_work,
 571                             "firmware/%s", name);
 572
 573         if (IS_ERR(task)) {
 574                 fw_work->cont(NULL, fw_work->context);
 575                 module_put(fw_work->module);
 576                 kfree(fw_work);
 577                 return PTR_ERR(task);
 578         }
 579         return 0;
 580 }
 581
 582 static int __init
 583 firmware_class_init(void)
 584 {
 585         int error;
 586         error = class_register(&firmware_class);
 587         if (error) {
 588                 printk(KERN_ERR "%s: class_register failed\n", __func__);
 589                 return error;
 590         }
 591         error = class_create_file(&firmware_class, &class_attr_timeout);
 592         if (error) {
 593                 printk(KERN_ERR "%s: class_create_file failed\n",
 594                        __func__);
 595                 class_unregister(&firmware_class);
 596         }
 597         return error;
 598
 599 }
 600 static void __exit
 601 firmware_class_exit(void)
 602 {
 603         class_unregister(&firmware_class);
 604 }
 605
 606 fs_initcall(firmware_class_init);
 607 module_exit(firmware_class_exit);
 608
 609 EXPORT_SYMBOL(release_firmware);
 610 EXPORT_SYMBOL(request_firmware);
 611 EXPORT_SYMBOL(request_firmware_nowait);