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                 printk(KERN_ERR "%s: unexpected value (%d)\n", __func__,
 168                        loading);
 169                 /* fallthrough */
 170         case -1:
 171                 fw_load_abort(fw_priv);
 172                 break;
 173         }
 174
 175         return count;
 176 }
 177
 178 static DEVICE_ATTR(loading, 0644, firmware_loading_show, firmware_loading_store);
 179
 180 static ssize_t
 181 firmware_data_read(struct kobject *kobj, struct bin_attribute *bin_attr,
 182                    char *buffer, loff_t offset, size_t count)
 183 {
 184         struct device *dev = to_dev(kobj);
 185         struct firmware_priv *fw_priv = dev_get_drvdata(dev);
 186         struct firmware *fw;
 187         ssize_t ret_count;
 188
 189         mutex_lock(&fw_lock);
 190         fw = fw_priv->fw;
 191         if (!fw || test_bit(FW_STATUS_DONE, &fw_priv->status)) {
 192                 ret_count = -ENODEV;
 193                 goto out;
 194         }
 195         ret_count = memory_read_from_buffer(buffer, count, &offset,
 196                                                 fw->data, fw->size);
 197 out:
 198         mutex_unlock(&fw_lock);
 199         return ret_count;
 200 }
 201
 202 static int
 203 fw_realloc_buffer(struct firmware_priv *fw_priv, int min_size)
 204 {
 205         u8 *new_data;
 206         int new_size = fw_priv->alloc_size;
 207
 208         if (min_size <= fw_priv->alloc_size)
 209                 return 0;
 210
 211         new_size = ALIGN(min_size, PAGE_SIZE);
 212         new_data = vmalloc(new_size);
 213         if (!new_data) {
 214                 printk(KERN_ERR "%s: unable to alloc buffer\n", __func__);
 215                 /* Make sure that we don't keep incomplete data */
 216                 fw_load_abort(fw_priv);
 217                 return -ENOMEM;
 218         }
 219         fw_priv->alloc_size = new_size;
 220         if (fw_priv->fw->data) {
 221                 memcpy(new_data, fw_priv->fw->data, fw_priv->fw->size);
 222                 vfree(fw_priv->fw->data);
 223         }
 224         fw_priv->fw->data = new_data;
 225         BUG_ON(min_size > fw_priv->alloc_size);
 226         return 0;
 227 }
 228
 229 /**
 230  * firmware_data_write - write method for firmware
 231  * @kobj: kobject for the device
 232  * @bin_attr: bin_attr structure
 233  * @buffer: buffer being written
 234  * @offset: buffer offset for write in total data store area
 235  * @count: buffer size
 236  *
 237  *      Data written to the 'data' attribute will be later handed to
 238  *      the driver as a firmware image.
 239  **/
 240 static ssize_t
 241 firmware_data_write(struct kobject *kobj, struct bin_attribute *bin_attr,
 242                     char *buffer, loff_t offset, size_t count)
 243 {
 244         struct device *dev = to_dev(kobj);
 245         struct firmware_priv *fw_priv = dev_get_drvdata(dev);
 246         struct firmware *fw;
 247         ssize_t retval;
 248
 249         if (!capable(CAP_SYS_RAWIO))
 250                 return -EPERM;
 251
 252         mutex_lock(&fw_lock);
 253         fw = fw_priv->fw;
 254         if (!fw || test_bit(FW_STATUS_DONE, &fw_priv->status)) {
 255                 retval = -ENODEV;
 256                 goto out;
 257         }
 258         retval = fw_realloc_buffer(fw_priv, offset + count);
 259         if (retval)
 260                 goto out;
 261
 262         memcpy((u8 *)fw->data + offset, buffer, count);
 263
 264         fw->size = max_t(size_t, offset + count, fw->size);
 265         retval = count;
 266 out:
 267         mutex_unlock(&fw_lock);
 268         return retval;
 269 }
 270
 271 static struct bin_attribute firmware_attr_data_tmpl = {
 272         .attr = {.name = "data", .mode = 0644},
 273         .size = 0,
 274         .read = firmware_data_read,
 275         .write = firmware_data_write,
 276 };
 277
 278 static void fw_dev_release(struct device *dev)
 279 {
 280         struct firmware_priv *fw_priv = dev_get_drvdata(dev);
 281
 282         kfree(fw_priv);
 283         kfree(dev);
 284
 285         module_put(THIS_MODULE);
 286 }
 287
 288 static void
 289 firmware_class_timeout(u_long data)
 290 {
 291         struct firmware_priv *fw_priv = (struct firmware_priv *) data;
 292         fw_load_abort(fw_priv);
 293 }
 294
 295 static inline void fw_setup_device_id(struct device *f_dev, struct device *dev)
 296 {
 297         /* XXX warning we should watch out for name collisions */
 298         strlcpy(f_dev->bus_id, dev->bus_id, BUS_ID_SIZE);
 299 }
 300
 301 static int fw_register_device(struct device **dev_p, const char *fw_name,
 302                               struct device *device)
 303 {
 304         int retval;
 305         struct firmware_priv *fw_priv = kzalloc(sizeof(*fw_priv),
 306                                                 GFP_KERNEL);
 307         struct device *f_dev = kzalloc(sizeof(*f_dev), GFP_KERNEL);
 308
 309         *dev_p = NULL;
 310
 311         if (!fw_priv || !f_dev) {
 312                 printk(KERN_ERR "%s: kmalloc failed\n", __func__);
 313                 retval = -ENOMEM;
 314                 goto error_kfree;
 315         }
 316
 317         init_completion(&fw_priv->completion);
 318         fw_priv->attr_data = firmware_attr_data_tmpl;
 319         strlcpy(fw_priv->fw_id, fw_name, FIRMWARE_NAME_MAX);
 320
 321         fw_priv->timeout.function = firmware_class_timeout;
 322         fw_priv->timeout.data = (u_long) fw_priv;
 323         init_timer(&fw_priv->timeout);
 324
 325         fw_setup_device_id(f_dev, device);
 326         f_dev->parent = device;
 327         f_dev->class = &firmware_class;
 328         dev_set_drvdata(f_dev, fw_priv);
 329         f_dev->uevent_suppress = 1;
 330         retval = device_register(f_dev);
 331         if (retval) {
 332                 printk(KERN_ERR "%s: device_register failed\n",
 333                        __func__);
 334                 goto error_kfree;
 335         }
 336         *dev_p = f_dev;
 337         return 0;
 338
 339 error_kfree:
 340         kfree(fw_priv);
 341         kfree(f_dev);
 342         return retval;
 343 }
 344
 345 static int fw_setup_device(struct firmware *fw, struct device **dev_p,
 346                            const char *fw_name, struct device *device,
 347                            int uevent)
 348 {
 349         struct device *f_dev;
 350         struct firmware_priv *fw_priv;
 351         int retval;
 352
 353         *dev_p = NULL;
 354         retval = fw_register_device(&f_dev, fw_name, device);
 355         if (retval)
 356                 goto out;
 357
 358         /* Need to pin this module until class device is destroyed */
 359         __module_get(THIS_MODULE);
 360
 361         fw_priv = dev_get_drvdata(f_dev);
 362
 363         fw_priv->fw = fw;
 364         retval = sysfs_create_bin_file(&f_dev->kobj, &fw_priv->attr_data);
 365         if (retval) {
 366                 printk(KERN_ERR "%s: sysfs_create_bin_file failed\n",
 367                        __func__);
 368                 goto error_unreg;
 369         }
 370
 371         retval = device_create_file(f_dev, &dev_attr_loading);
 372         if (retval) {
 373                 printk(KERN_ERR "%s: device_create_file failed\n",
 374                        __func__);
 375                 goto error_unreg;
 376         }
 377
 378         if (uevent)
 379                 f_dev->uevent_suppress = 0;
 380         *dev_p = f_dev;
 381         goto out;
 382
 383 error_unreg:
 384         device_unregister(f_dev);
 385 out:
 386         return retval;
 387 }
 388
 389 static int
 390 _request_firmware(const struct firmware **firmware_p, const char *name,
 391                  struct device *device, int uevent)
 392 {
 393         struct device *f_dev;
 394         struct firmware_priv *fw_priv;
 395         struct firmware *firmware;
 396         struct builtin_fw *builtin;
 397         int retval;
 398
 399         if (!firmware_p)
 400                 return -EINVAL;
 401
 402         *firmware_p = firmware = kzalloc(sizeof(*firmware), GFP_KERNEL);
 403         if (!firmware) {
 404                 printk(KERN_ERR "%s: kmalloc(struct firmware) failed\n",
 405                        __func__);
 406                 retval = -ENOMEM;
 407                 goto out;
 408         }
 409
 410         for (builtin = __start_builtin_fw; builtin != __end_builtin_fw;
 411              builtin++) {
 412                 if (strcmp(name, builtin->name))
 413                         continue;
 414                 printk(KERN_INFO "firmware: using built-in firmware %s\n",
 415                        name);
 416                 firmware->size = builtin->size;
 417                 firmware->data = builtin->data;
 418                 return 0;
 419         }
 420
 421         if (uevent)
 422                 printk(KERN_INFO "firmware: requesting %s\n", name);
 423
 424         retval = fw_setup_device(firmware, &f_dev, name, device, uevent);
 425         if (retval)
 426                 goto error_kfree_fw;
 427
 428         fw_priv = dev_get_drvdata(f_dev);
 429
 430         if (uevent) {
 431                 if (loading_timeout > 0) {
 432                         fw_priv->timeout.expires = jiffies + loading_timeout * HZ;
 433                         add_timer(&fw_priv->timeout);
 434                 }
 435
 436                 kobject_uevent(&f_dev->kobj, KOBJ_ADD);
 437                 wait_for_completion(&fw_priv->completion);
 438                 set_bit(FW_STATUS_DONE, &fw_priv->status);
 439                 del_timer_sync(&fw_priv->timeout);
 440         } else
 441                 wait_for_completion(&fw_priv->completion);
 442
 443         mutex_lock(&fw_lock);
 444         if (!fw_priv->fw->size || test_bit(FW_STATUS_ABORT, &fw_priv->status)) {
 445                 retval = -ENOENT;
 446                 release_firmware(fw_priv->fw);
 447                 *firmware_p = NULL;
 448         }
 449         fw_priv->fw = NULL;
 450         mutex_unlock(&fw_lock);
 451         device_unregister(f_dev);
 452         goto out;
 453
 454 error_kfree_fw:
 455         kfree(firmware);
 456         *firmware_p = NULL;
 457 out:
 458         return retval;
 459 }
 460
 461 /**
 462  * request_firmware: - send firmware request and wait for it
 463  * @firmware_p: pointer to firmware image
 464  * @name: name of firmware file
 465  * @device: device for which firmware is being loaded
 466  *
 467  *      @firmware_p will be used to return a firmware image by the name
 468  *      of @name for device @device.
 469  *
 470  *      Should be called from user context where sleeping is allowed.
 471  *
 472  *      @name will be used as $FIRMWARE in the uevent environment and
 473  *      should be distinctive enough not to be confused with any other
 474  *      firmware image for this or any other device.
 475  **/
 476 int
 477 request_firmware(const struct firmware **firmware_p, const char *name,
 478                  struct device *device)
 479 {
 480         int uevent = 1;
 481         return _request_firmware(firmware_p, name, device, uevent);
 482 }
 483
 484 /**
 485  * release_firmware: - release the resource associated with a firmware image
 486  * @fw: firmware resource to release
 487  **/
 488 void
 489 release_firmware(const struct firmware *fw)
 490 {
 491         struct builtin_fw *builtin;
 492
 493         if (fw) {
 494                 for (builtin = __start_builtin_fw; builtin != __end_builtin_fw;
 495                      builtin++) {
 496                         if (fw->data == builtin->data)
 497                                 goto free_fw;
 498                 }
 499                 vfree(fw->data);
 500         free_fw:
 501                 kfree(fw);
 502         }
 503 }
 504
 505 /* Async support */
 506 struct firmware_work {
 507         struct work_struct work;
 508         struct module *module;
 509         const char *name;
 510         struct device *device;
 511         void *context;
 512         void (*cont)(const struct firmware *fw, void *context);
 513         int uevent;
 514 };
 515
 516 static int
 517 request_firmware_work_func(void *arg)
 518 {
 519         struct firmware_work *fw_work = arg;
 520         const struct firmware *fw;
 521         int ret;
 522         if (!arg) {
 523                 WARN_ON(1);
 524                 return 0;
 525         }
 526         ret = _request_firmware(&fw, fw_work->name, fw_work->device,
 527                 fw_work->uevent);
 528         if (ret < 0)
 529                 fw_work->cont(NULL, fw_work->context);
 530         else {
 531                 fw_work->cont(fw, fw_work->context);
 532                 release_firmware(fw);
 533         }
 534         module_put(fw_work->module);
 535         kfree(fw_work);
 536         return ret;
 537 }
 538
 539 /**
 540  * request_firmware_nowait: asynchronous version of request_firmware
 541  * @module: module requesting the firmware
 542  * @uevent: sends uevent to copy the firmware image if this flag
 543  *      is non-zero else the firmware copy must be done manually.
 544  * @name: name of firmware file
 545  * @device: device for which firmware is being loaded
 546  * @context: will be passed over to @cont, and
 547  *      @fw may be %NULL if firmware request fails.
 548  * @cont: function will be called asynchronously when the firmware
 549  *      request is over.
 550  *
 551  *      Asynchronous variant of request_firmware() for contexts where
 552  *      it is not possible to sleep.
 553  **/
 554 int
 555 request_firmware_nowait(
 556         struct module *module, int uevent,
 557         const char *name, struct device *device, void *context,
 558         void (*cont)(const struct firmware *fw, void *context))
 559 {
 560         struct task_struct *task;
 561         struct firmware_work *fw_work = kmalloc(sizeof (struct firmware_work),
 562                                                 GFP_ATOMIC);
 563
 564         if (!fw_work)
 565                 return -ENOMEM;
 566         if (!try_module_get(module)) {
 567                 kfree(fw_work);
 568                 return -EFAULT;
 569         }
 570
 571         *fw_work = (struct firmware_work) {
 572                 .module = module,
 573                 .name = name,
 574                 .device = device,
 575                 .context = context,
 576                 .cont = cont,
 577                 .uevent = uevent,
 578         };
 579
 580         task = kthread_run(request_firmware_work_func, fw_work,
 581                             "firmware/%s", name);
 582
 583         if (IS_ERR(task)) {
 584                 fw_work->cont(NULL, fw_work->context);
 585                 module_put(fw_work->module);
 586                 kfree(fw_work);
 587                 return PTR_ERR(task);
 588         }
 589         return 0;
 590 }
 591
 592 static int __init
 593 firmware_class_init(void)
 594 {
 595         int error;
 596         error = class_register(&firmware_class);
 597         if (error) {
 598                 printk(KERN_ERR "%s: class_register failed\n", __func__);
 599                 return error;
 600         }
 601         error = class_create_file(&firmware_class, &class_attr_timeout);
 602         if (error) {
 603                 printk(KERN_ERR "%s: class_create_file failed\n",
 604                        __func__);
 605                 class_unregister(&firmware_class);
 606         }
 607         return error;
 608
 609 }
 610 static void __exit
 611 firmware_class_exit(void)
 612 {
 613         class_unregister(&firmware_class);
 614 }
 615
 616 fs_initcall(firmware_class_init);
 617 module_exit(firmware_class_exit);
 618
 619 EXPORT_SYMBOL(release_firmware);
 620 EXPORT_SYMBOL(request_firmware);
 621 EXPORT_SYMBOL(request_firmware_nowait);