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 inline void fw_setup_device_id(struct device *f_dev, struct device *dev)
 295 {
 296         /* XXX warning we should watch out for name collisions */
 297         strlcpy(f_dev->bus_id, dev->bus_id, BUS_ID_SIZE);
 298 }
 299
 300 static int fw_register_device(struct device **dev_p, const char *fw_name,
 301                               struct device *device)
 302 {
 303         int retval;
 304         struct firmware_priv *fw_priv = kzalloc(sizeof(*fw_priv),
 305                                                 GFP_KERNEL);
 306         struct device *f_dev = kzalloc(sizeof(*f_dev), GFP_KERNEL);
 307
 308         *dev_p = NULL;
 309
 310         if (!fw_priv || !f_dev) {
 311                 dev_err(device, "%s: kmalloc failed\n", __func__);
 312                 retval = -ENOMEM;
 313                 goto error_kfree;
 314         }
 315
 316         init_completion(&fw_priv->completion);
 317         fw_priv->attr_data = firmware_attr_data_tmpl;
 318         strlcpy(fw_priv->fw_id, fw_name, FIRMWARE_NAME_MAX);
 319
 320         fw_priv->timeout.function = firmware_class_timeout;
 321         fw_priv->timeout.data = (u_long) fw_priv;
 322         init_timer(&fw_priv->timeout);
 323
 324         fw_setup_device_id(f_dev, device);
 325         f_dev->parent = device;
 326         f_dev->class = &firmware_class;
 327         dev_set_drvdata(f_dev, fw_priv);
 328         f_dev->uevent_suppress = 1;
 329         retval = device_register(f_dev);
 330         if (retval) {
 331                 dev_err(device, "%s: device_register failed\n", __func__);
 332                 goto error_kfree;
 333         }
 334         *dev_p = f_dev;
 335         return 0;
 336
 337 error_kfree:
 338         kfree(fw_priv);
 339         kfree(f_dev);
 340         return retval;
 341 }
 342
 343 static int fw_setup_device(struct firmware *fw, struct device **dev_p,
 344                            const char *fw_name, struct device *device,
 345                            int uevent)
 346 {
 347         struct device *f_dev;
 348         struct firmware_priv *fw_priv;
 349         int retval;
 350
 351         *dev_p = NULL;
 352         retval = fw_register_device(&f_dev, fw_name, device);
 353         if (retval)
 354                 goto out;
 355
 356         /* Need to pin this module until class device is destroyed */
 357         __module_get(THIS_MODULE);
 358
 359         fw_priv = dev_get_drvdata(f_dev);
 360
 361         fw_priv->fw = fw;
 362         retval = sysfs_create_bin_file(&f_dev->kobj, &fw_priv->attr_data);
 363         if (retval) {
 364                 dev_err(device, "%s: sysfs_create_bin_file failed\n", __func__);
 365                 goto error_unreg;
 366         }
 367
 368         retval = device_create_file(f_dev, &dev_attr_loading);
 369         if (retval) {
 370                 dev_err(device, "%s: device_create_file failed\n", __func__);
 371                 goto error_unreg;
 372         }
 373
 374         if (uevent)
 375                 f_dev->uevent_suppress = 0;
 376         *dev_p = f_dev;
 377         goto out;
 378
 379 error_unreg:
 380         device_unregister(f_dev);
 381 out:
 382         return retval;
 383 }
 384
 385 static int
 386 _request_firmware(const struct firmware **firmware_p, const char *name,
 387                  struct device *device, int uevent)
 388 {
 389         struct device *f_dev;
 390         struct firmware_priv *fw_priv;
 391         struct firmware *firmware;
 392         struct builtin_fw *builtin;
 393         int retval;
 394
 395         if (!firmware_p)
 396                 return -EINVAL;
 397
 398         *firmware_p = firmware = kzalloc(sizeof(*firmware), GFP_KERNEL);
 399         if (!firmware) {
 400                 dev_err(device, "%s: kmalloc(struct firmware) failed\n",
 401                         __func__);
 402                 retval = -ENOMEM;
 403                 goto out;
 404         }
 405
 406         for (builtin = __start_builtin_fw; builtin != __end_builtin_fw;
 407              builtin++) {
 408                 if (strcmp(name, builtin->name))
 409                         continue;
 410                 dev_info(device, "firmware: using built-in firmware %s\n",
 411                          name);
 412                 firmware->size = builtin->size;
 413                 firmware->data = builtin->data;
 414                 return 0;
 415         }
 416
 417         if (uevent)
 418                 dev_info(device, "firmware: requesting %s\n", name);
 419
 420         retval = fw_setup_device(firmware, &f_dev, name, device, uevent);
 421         if (retval)
 422                 goto error_kfree_fw;
 423
 424         fw_priv = dev_get_drvdata(f_dev);
 425
 426         if (uevent) {
 427                 if (loading_timeout > 0) {
 428                         fw_priv->timeout.expires = jiffies + loading_timeout * HZ;
 429                         add_timer(&fw_priv->timeout);
 430                 }
 431
 432                 kobject_uevent(&f_dev->kobj, KOBJ_ADD);
 433                 wait_for_completion(&fw_priv->completion);
 434                 set_bit(FW_STATUS_DONE, &fw_priv->status);
 435                 del_timer_sync(&fw_priv->timeout);
 436         } else
 437                 wait_for_completion(&fw_priv->completion);
 438
 439         mutex_lock(&fw_lock);
 440         if (!fw_priv->fw->size || test_bit(FW_STATUS_ABORT, &fw_priv->status)) {
 441                 retval = -ENOENT;
 442                 release_firmware(fw_priv->fw);
 443                 *firmware_p = NULL;
 444         }
 445         fw_priv->fw = NULL;
 446         mutex_unlock(&fw_lock);
 447         device_unregister(f_dev);
 448         goto out;
 449
 450 error_kfree_fw:
 451         kfree(firmware);
 452         *firmware_p = NULL;
 453 out:
 454         return retval;
 455 }
 456
 457 /**
 458  * request_firmware: - send firmware request and wait for it
 459  * @firmware_p: pointer to firmware image
 460  * @name: name of firmware file
 461  * @device: device for which firmware is being loaded
 462  *
 463  *      @firmware_p will be used to return a firmware image by the name
 464  *      of @name for device @device.
 465  *
 466  *      Should be called from user context where sleeping is allowed.
 467  *
 468  *      @name will be used as $FIRMWARE in the uevent environment and
 469  *      should be distinctive enough not to be confused with any other
 470  *      firmware image for this or any other device.
 471  **/
 472 int
 473 request_firmware(const struct firmware **firmware_p, const char *name,
 474                  struct device *device)
 475 {
 476         int uevent = 1;
 477         return _request_firmware(firmware_p, name, device, uevent);
 478 }
 479
 480 /**
 481  * release_firmware: - release the resource associated with a firmware image
 482  * @fw: firmware resource to release
 483  **/
 484 void
 485 release_firmware(const struct firmware *fw)
 486 {
 487         struct builtin_fw *builtin;
 488
 489         if (fw) {
 490                 for (builtin = __start_builtin_fw; builtin != __end_builtin_fw;
 491                      builtin++) {
 492                         if (fw->data == builtin->data)
 493                                 goto free_fw;
 494                 }
 495                 vfree(fw->data);
 496         free_fw:
 497                 kfree(fw);
 498         }
 499 }
 500
 501 /* Async support */
 502 struct firmware_work {
 503         struct work_struct work;
 504         struct module *module;
 505         const char *name;
 506         struct device *device;
 507         void *context;
 508         void (*cont)(const struct firmware *fw, void *context);
 509         int uevent;
 510 };
 511
 512 static int
 513 request_firmware_work_func(void *arg)
 514 {
 515         struct firmware_work *fw_work = arg;
 516         const struct firmware *fw;
 517         int ret;
 518         if (!arg) {
 519                 WARN_ON(1);
 520                 return 0;
 521         }
 522         ret = _request_firmware(&fw, fw_work->name, fw_work->device,
 523                 fw_work->uevent);
 524         if (ret < 0)
 525                 fw_work->cont(NULL, fw_work->context);
 526         else {
 527                 fw_work->cont(fw, fw_work->context);
 528                 release_firmware(fw);
 529         }
 530         module_put(fw_work->module);
 531         kfree(fw_work);
 532         return ret;
 533 }
 534
 535 /**
 536  * request_firmware_nowait: asynchronous version of request_firmware
 537  * @module: module requesting the firmware
 538  * @uevent: sends uevent to copy the firmware image if this flag
 539  *      is non-zero else the firmware copy must be done manually.
 540  * @name: name of firmware file
 541  * @device: device for which firmware is being loaded
 542  * @context: will be passed over to @cont, and
 543  *      @fw may be %NULL if firmware request fails.
 544  * @cont: function will be called asynchronously when the firmware
 545  *      request is over.
 546  *
 547  *      Asynchronous variant of request_firmware() for contexts where
 548  *      it is not possible to sleep.
 549  **/
 550 int
 551 request_firmware_nowait(
 552         struct module *module, int uevent,
 553         const char *name, struct device *device, void *context,
 554         void (*cont)(const struct firmware *fw, void *context))
 555 {
 556         struct task_struct *task;
 557         struct firmware_work *fw_work = kmalloc(sizeof (struct firmware_work),
 558                                                 GFP_ATOMIC);
 559
 560         if (!fw_work)
 561                 return -ENOMEM;
 562         if (!try_module_get(module)) {
 563                 kfree(fw_work);
 564                 return -EFAULT;
 565         }
 566
 567         *fw_work = (struct firmware_work) {
 568                 .module = module,
 569                 .name = name,
 570                 .device = device,
 571                 .context = context,
 572                 .cont = cont,
 573                 .uevent = uevent,
 574         };
 575
 576         task = kthread_run(request_firmware_work_func, fw_work,
 577                             "firmware/%s", name);
 578
 579         if (IS_ERR(task)) {
 580                 fw_work->cont(NULL, fw_work->context);
 581                 module_put(fw_work->module);
 582                 kfree(fw_work);
 583                 return PTR_ERR(task);
 584         }
 585         return 0;
 586 }
 587
 588 static int __init
 589 firmware_class_init(void)
 590 {
 591         int error;
 592         error = class_register(&firmware_class);
 593         if (error) {
 594                 printk(KERN_ERR "%s: class_register failed\n", __func__);
 595                 return error;
 596         }
 597         error = class_create_file(&firmware_class, &class_attr_timeout);
 598         if (error) {
 599                 printk(KERN_ERR "%s: class_create_file failed\n",
 600                        __func__);
 601                 class_unregister(&firmware_class);
 602         }
 603         return error;
 604
 605 }
 606 static void __exit
 607 firmware_class_exit(void)
 608 {
 609         class_unregister(&firmware_class);
 610 }
 611
 612 fs_initcall(firmware_class_init);
 613 module_exit(firmware_class_exit);
 614
 615 EXPORT_SYMBOL(release_firmware);
 616 EXPORT_SYMBOL(request_firmware);
 617 EXPORT_SYMBOL(request_firmware_nowait);