drivers/base/firmware_class.c

   1 /*
   2  * firmware_class.c - Multi purpose firmware loading support
   3  *
   4  * Copyright (c) 2003 Manuel Estrada Sainz <ranty@debian.org>
   5  *
   6  * Please see Documentation/firmware_class/ for more information.
   7  *
   8  */
   9
  10 #include <linux/device.h>
  11 #include <linux/module.h>
  12 #include <linux/init.h>
  13 #include <linux/timer.h>
  14 #include <linux/vmalloc.h>
  15 #include <linux/interrupt.h>
  16 #include <linux/bitops.h>
  17 #include <asm/semaphore.h>
  18
  19 #include <linux/firmware.h>
  20 #include "base.h"
  21
  22 MODULE_AUTHOR("Manuel Estrada Sainz <ranty@debian.org>");
  23 MODULE_DESCRIPTION("Multi purpose firmware loading support");
  24 MODULE_LICENSE("GPL");
  25
  26 enum {
  27         FW_STATUS_LOADING,
  28         FW_STATUS_DONE,
  29         FW_STATUS_ABORT,
  30         FW_STATUS_READY,
  31         FW_STATUS_READY_NOHOTPLUG,
  32 };
  33
  34 static int loading_timeout = 10;        /* In seconds */
  35
  36 /* fw_lock could be moved to 'struct firmware_priv' but since it is just
  37  * guarding for corner cases a global lock should be OK */
  38 static DECLARE_MUTEX(fw_lock);
  39
  40 struct firmware_priv {
  41         char fw_id[FIRMWARE_NAME_MAX];
  42         struct completion completion;
  43         struct bin_attribute attr_data;
  44         struct firmware *fw;
  45         unsigned long status;
  46         int alloc_size;
  47         struct timer_list timeout;
  48 };
  49
  50 static inline void
  51 fw_load_abort(struct firmware_priv *fw_priv)
  52 {
  53         set_bit(FW_STATUS_ABORT, &fw_priv->status);
  54         wmb();
  55         complete(&fw_priv->completion);
  56 }
  57
  58 static ssize_t
  59 firmware_timeout_show(struct class *class, char *buf)
  60 {
  61         return sprintf(buf, "%d\n", loading_timeout);
  62 }
  63
  64 /**
  65  * firmware_timeout_store:
  66  * Description:
  67  *      Sets the number of seconds to wait for the firmware.  Once
  68  *      this expires an error will be return to the driver and no
  69  *      firmware will be provided.
  70  *
  71  *      Note: zero means 'wait for ever'
  72  *
  73  **/
  74 static ssize_t
  75 firmware_timeout_store(struct class *class, const char *buf, size_t count)
  76 {
  77         loading_timeout = simple_strtol(buf, NULL, 10);
  78         if (loading_timeout < 0)
  79                 loading_timeout = 0;
  80         return count;
  81 }
  82
  83 static CLASS_ATTR(timeout, 0644, firmware_timeout_show, firmware_timeout_store);
  84
  85 static void  fw_class_dev_release(struct class_device *class_dev);
  86 int firmware_class_hotplug(struct class_device *dev, char **envp,
  87                            int num_envp, char *buffer, int buffer_size);
  88
  89 static struct class firmware_class = {
  90         .name           = "firmware",
  91         .hotplug        = firmware_class_hotplug,
  92         .release        = fw_class_dev_release,
  93 };
  94
  95 int
  96 firmware_class_hotplug(struct class_device *class_dev, char **envp,
  97                        int num_envp, char *buffer, int buffer_size)
  98 {
  99         struct firmware_priv *fw_priv = class_get_devdata(class_dev);
 100         int i = 0, len = 0;
 101
 102         if (!test_bit(FW_STATUS_READY, &fw_priv->status))
 103                 return -ENODEV;
 104
 105         if (add_hotplug_env_var(envp, num_envp, &i, buffer, buffer_size, &len,
 106                         "FIRMWARE=%s", fw_priv->fw_id))
 107                 return -ENOMEM;
 108         if (add_hotplug_env_var(envp, num_envp, &i, buffer, buffer_size, &len,
 109                         "TIMEOUT=%i", loading_timeout))
 110                 return -ENOMEM;
 111
 112         envp[i] = NULL;
 113
 114         return 0;
 115 }
 116
 117 static ssize_t
 118 firmware_loading_show(struct class_device *class_dev, char *buf)
 119 {
 120         struct firmware_priv *fw_priv = class_get_devdata(class_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: - loading control file
 127  * Description:
 128  *      The relevant values are:
 129  *
 130  *       1: Start a load, discarding any previous partial load.
 131  *       0: Conclude the load and handle the data to the driver code.
 132  *      -1: Conclude the load with an error and discard any written data.
 133  **/
 134 static ssize_t
 135 firmware_loading_store(struct class_device *class_dev,
 136                        const char *buf, size_t count)
 137 {
 138         struct firmware_priv *fw_priv = class_get_devdata(class_dev);
 139         int loading = simple_strtol(buf, NULL, 10);
 140
 141         switch (loading) {
 142         case 1:
 143                 down(&fw_lock);
 144                 if (!fw_priv->fw) {
 145                         up(&fw_lock);
 146                         break;
 147                 }
 148                 vfree(fw_priv->fw->data);
 149                 fw_priv->fw->data = NULL;
 150                 fw_priv->fw->size = 0;
 151                 fw_priv->alloc_size = 0;
 152                 set_bit(FW_STATUS_LOADING, &fw_priv->status);
 153                 up(&fw_lock);
 154                 break;
 155         case 0:
 156                 if (test_bit(FW_STATUS_LOADING, &fw_priv->status)) {
 157                         complete(&fw_priv->completion);
 158                         clear_bit(FW_STATUS_LOADING, &fw_priv->status);
 159                         break;
 160                 }
 161                 /* fallthrough */
 162         default:
 163                 printk(KERN_ERR "%s: unexpected value (%d)\n", __FUNCTION__,
 164                        loading);
 165                 /* fallthrough */
 166         case -1:
 167                 fw_load_abort(fw_priv);
 168                 break;
 169         }
 170
 171         return count;
 172 }
 173
 174 static CLASS_DEVICE_ATTR(loading, 0644,
 175                         firmware_loading_show, firmware_loading_store);
 176
 177 static ssize_t
 178 firmware_data_read(struct kobject *kobj,
 179                    char *buffer, loff_t offset, size_t count)
 180 {
 181         struct class_device *class_dev = to_class_dev(kobj);
 182         struct firmware_priv *fw_priv = class_get_devdata(class_dev);
 183         struct firmware *fw;
 184         ssize_t ret_count = count;
 185
 186         down(&fw_lock);
 187         fw = fw_priv->fw;
 188         if (!fw || test_bit(FW_STATUS_DONE, &fw_priv->status)) {
 189                 ret_count = -ENODEV;
 190                 goto out;
 191         }
 192         if (offset > fw->size) {
 193                 ret_count = 0;
 194                 goto out;
 195         }
 196         if (offset + ret_count > fw->size)
 197                 ret_count = fw->size - offset;
 198
 199         memcpy(buffer, fw->data + offset, ret_count);
 200 out:
 201         up(&fw_lock);
 202         return ret_count;
 203 }
 204 static int
 205 fw_realloc_buffer(struct firmware_priv *fw_priv, int min_size)
 206 {
 207         u8 *new_data;
 208
 209         if (min_size <= fw_priv->alloc_size)
 210                 return 0;
 211
 212         new_data = vmalloc(fw_priv->alloc_size + PAGE_SIZE);
 213         if (!new_data) {
 214                 printk(KERN_ERR "%s: unable to alloc buffer\n", __FUNCTION__);
 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 += PAGE_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:
 231  *
 232  * Description:
 233  *
 234  *      Data written to the 'data' attribute will be later handled to
 235  *      the driver as a firmware image.
 236  **/
 237 static ssize_t
 238 firmware_data_write(struct kobject *kobj,
 239                     char *buffer, loff_t offset, size_t count)
 240 {
 241         struct class_device *class_dev = to_class_dev(kobj);
 242         struct firmware_priv *fw_priv = class_get_devdata(class_dev);
 243         struct firmware *fw;
 244         ssize_t retval;
 245
 246         if (!capable(CAP_SYS_RAWIO))
 247                 return -EPERM;
 248
 249         down(&fw_lock);
 250         fw = fw_priv->fw;
 251         if (!fw || test_bit(FW_STATUS_DONE, &fw_priv->status)) {
 252                 retval = -ENODEV;
 253                 goto out;
 254         }
 255         retval = fw_realloc_buffer(fw_priv, offset + count);
 256         if (retval)
 257                 goto out;
 258
 259         memcpy(fw->data + offset, buffer, count);
 260
 261         fw->size = max_t(size_t, offset + count, fw->size);
 262         retval = count;
 263 out:
 264         up(&fw_lock);
 265         return retval;
 266 }
 267 static struct bin_attribute firmware_attr_data_tmpl = {
 268         .attr = {.name = "data", .mode = 0644, .owner = THIS_MODULE},
 269         .size = 0,
 270         .read = firmware_data_read,
 271         .write = firmware_data_write,
 272 };
 273
 274 static void
 275 fw_class_dev_release(struct class_device *class_dev)
 276 {
 277         struct firmware_priv *fw_priv = class_get_devdata(class_dev);
 278
 279         kfree(fw_priv);
 280         kfree(class_dev);
 281
 282         module_put(THIS_MODULE);
 283 }
 284
 285 static void
 286 firmware_class_timeout(u_long data)
 287 {
 288         struct firmware_priv *fw_priv = (struct firmware_priv *) data;
 289         fw_load_abort(fw_priv);
 290 }
 291
 292 static inline void
 293 fw_setup_class_device_id(struct class_device *class_dev, struct device *dev)
 294 {
 295         /* XXX warning we should watch out for name collisions */
 296         strlcpy(class_dev->class_id, dev->bus_id, BUS_ID_SIZE);
 297 }
 298
 299 static int
 300 fw_register_class_device(struct class_device **class_dev_p,
 301                          const char *fw_name, struct device *device)
 302 {
 303         int retval;
 304         struct firmware_priv *fw_priv = kzalloc(sizeof(*fw_priv),
 305                                                 GFP_KERNEL);
 306         struct class_device *class_dev = kzalloc(sizeof(*class_dev),
 307                                                  GFP_KERNEL);
 308
 309         *class_dev_p = NULL;
 310
 311         if (!fw_priv || !class_dev) {
 312                 printk(KERN_ERR "%s: kmalloc failed\n", __FUNCTION__);
 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_class_device_id(class_dev, device);
 326         class_dev->dev = device;
 327         class_dev->class = &firmware_class;
 328         class_set_devdata(class_dev, fw_priv);
 329         retval = class_device_register(class_dev);
 330         if (retval) {
 331                 printk(KERN_ERR "%s: class_device_register failed\n",
 332                        __FUNCTION__);
 333                 goto error_kfree;
 334         }
 335         *class_dev_p = class_dev;
 336         return 0;
 337
 338 error_kfree:
 339         kfree(fw_priv);
 340         kfree(class_dev);
 341         return retval;
 342 }
 343
 344 static int
 345 fw_setup_class_device(struct firmware *fw, struct class_device **class_dev_p,
 346                       const char *fw_name, struct device *device, int hotplug)
 347 {
 348         struct class_device *class_dev;
 349         struct firmware_priv *fw_priv;
 350         int retval;
 351
 352         *class_dev_p = NULL;
 353         retval = fw_register_class_device(&class_dev, fw_name, device);
 354         if (retval)
 355                 goto out;
 356
 357         /* Need to pin this module until class device is destroyed */
 358         __module_get(THIS_MODULE);
 359
 360         fw_priv = class_get_devdata(class_dev);
 361
 362         fw_priv->fw = fw;
 363         retval = sysfs_create_bin_file(&class_dev->kobj, &fw_priv->attr_data);
 364         if (retval) {
 365                 printk(KERN_ERR "%s: sysfs_create_bin_file failed\n",
 366                        __FUNCTION__);
 367                 goto error_unreg;
 368         }
 369
 370         retval = class_device_create_file(class_dev,
 371                                           &class_device_attr_loading);
 372         if (retval) {
 373                 printk(KERN_ERR "%s: class_device_create_file failed\n",
 374                        __FUNCTION__);
 375                 goto error_unreg;
 376         }
 377
 378         if (hotplug)
 379                 set_bit(FW_STATUS_READY, &fw_priv->status);
 380         else
 381                 set_bit(FW_STATUS_READY_NOHOTPLUG, &fw_priv->status);
 382         *class_dev_p = class_dev;
 383         goto out;
 384
 385 error_unreg:
 386         class_device_unregister(class_dev);
 387 out:
 388         return retval;
 389 }
 390
 391 static int
 392 _request_firmware(const struct firmware **firmware_p, const char *name,
 393                  struct device *device, int hotplug)
 394 {
 395         struct class_device *class_dev;
 396         struct firmware_priv *fw_priv;
 397         struct firmware *firmware;
 398         int retval;
 399
 400         if (!firmware_p)
 401                 return -EINVAL;
 402
 403         *firmware_p = firmware = kzalloc(sizeof(*firmware), GFP_KERNEL);
 404         if (!firmware) {
 405                 printk(KERN_ERR "%s: kmalloc(struct firmware) failed\n",
 406                        __FUNCTION__);
 407                 retval = -ENOMEM;
 408                 goto out;
 409         }
 410
 411         retval = fw_setup_class_device(firmware, &class_dev, name, device,
 412                 hotplug);
 413         if (retval)
 414                 goto error_kfree_fw;
 415
 416         fw_priv = class_get_devdata(class_dev);
 417
 418         if (hotplug) {
 419                 if (loading_timeout > 0) {
 420                         fw_priv->timeout.expires = jiffies + loading_timeout * HZ;
 421                         add_timer(&fw_priv->timeout);
 422                 }
 423
 424                 kobject_hotplug(&class_dev->kobj, KOBJ_ADD);
 425                 wait_for_completion(&fw_priv->completion);
 426                 set_bit(FW_STATUS_DONE, &fw_priv->status);
 427                 del_timer_sync(&fw_priv->timeout);
 428         } else
 429                 wait_for_completion(&fw_priv->completion);
 430
 431         down(&fw_lock);
 432         if (!fw_priv->fw->size || test_bit(FW_STATUS_ABORT, &fw_priv->status)) {
 433                 retval = -ENOENT;
 434                 release_firmware(fw_priv->fw);
 435                 *firmware_p = NULL;
 436         }
 437         fw_priv->fw = NULL;
 438         up(&fw_lock);
 439         class_device_unregister(class_dev);
 440         goto out;
 441
 442 error_kfree_fw:
 443         kfree(firmware);
 444         *firmware_p = NULL;
 445 out:
 446         return retval;
 447 }
 448
 449 /**
 450  * request_firmware: - request firmware to hotplug and wait for it
 451  * Description:
 452  *      @firmware will be used to return a firmware image by the name
 453  *      of @name for device @device.
 454  *
 455  *      Should be called from user context where sleeping is allowed.
 456  *
 457  *      @name will be use as $FIRMWARE in the hotplug environment and
 458  *      should be distinctive enough not to be confused with any other
 459  *      firmware image for this or any other device.
 460  **/
 461 int
 462 request_firmware(const struct firmware **firmware_p, const char *name,
 463                  struct device *device)
 464 {
 465         int hotplug = 1;
 466         return _request_firmware(firmware_p, name, device, hotplug);
 467 }
 468
 469 /**
 470  * release_firmware: - release the resource associated with a firmware image
 471  **/
 472 void
 473 release_firmware(const struct firmware *fw)
 474 {
 475         if (fw) {
 476                 vfree(fw->data);
 477                 kfree(fw);
 478         }
 479 }
 480
 481 /**
 482  * register_firmware: - provide a firmware image for later usage
 483  *
 484  * Description:
 485  *      Make sure that @data will be available by requesting firmware @name.
 486  *
 487  *      Note: This will not be possible until some kind of persistence
 488  *      is available.
 489  **/
 490 void
 491 register_firmware(const char *name, const u8 *data, size_t size)
 492 {
 493         /* This is meaningless without firmware caching, so until we
 494          * decide if firmware caching is reasonable just leave it as a
 495          * noop */
 496 }
 497
 498 /* Async support */
 499 struct firmware_work {
 500         struct work_struct work;
 501         struct module *module;
 502         const char *name;
 503         struct device *device;
 504         void *context;
 505         void (*cont)(const struct firmware *fw, void *context);
 506         int hotplug;
 507 };
 508
 509 static int
 510 request_firmware_work_func(void *arg)
 511 {
 512         struct firmware_work *fw_work = arg;
 513         const struct firmware *fw;
 514         if (!arg) {
 515                 WARN_ON(1);
 516                 return 0;
 517         }
 518         daemonize("%s/%s", "firmware", fw_work->name);
 519         _request_firmware(&fw, fw_work->name, fw_work->device,
 520                 fw_work->hotplug);
 521         fw_work->cont(fw, fw_work->context);
 522         release_firmware(fw);
 523         module_put(fw_work->module);
 524         kfree(fw_work);
 525         return 0;
 526 }
 527
 528 /**
 529  * request_firmware_nowait:
 530  *
 531  * Description:
 532  *      Asynchronous variant of request_firmware() for contexts where
 533  *      it is not possible to sleep.
 534  *
 535  *      @hotplug invokes hotplug event to copy the firmware image if this flag
 536  *      is non-zero else the firmware copy must be done manually.
 537  *
 538  *      @cont will be called asynchronously when the firmware request is over.
 539  *
 540  *      @context will be passed over to @cont.
 541  *
 542  *      @fw may be %NULL if firmware request fails.
 543  *
 544  **/
 545 int
 546 request_firmware_nowait(
 547         struct module *module, int hotplug,
 548         const char *name, struct device *device, void *context,
 549         void (*cont)(const struct firmware *fw, void *context))
 550 {
 551         struct firmware_work *fw_work = kmalloc(sizeof (struct firmware_work),
 552                                                 GFP_ATOMIC);
 553         int ret;
 554
 555         if (!fw_work)
 556                 return -ENOMEM;
 557         if (!try_module_get(module)) {
 558                 kfree(fw_work);
 559                 return -EFAULT;
 560         }
 561
 562         *fw_work = (struct firmware_work) {
 563                 .module = module,
 564                 .name = name,
 565                 .device = device,
 566                 .context = context,
 567                 .cont = cont,
 568                 .hotplug = hotplug,
 569         };
 570
 571         ret = kernel_thread(request_firmware_work_func, fw_work,
 572                             CLONE_FS | CLONE_FILES);
 573
 574         if (ret < 0) {
 575                 fw_work->cont(NULL, fw_work->context);
 576                 return ret;
 577         }
 578         return 0;
 579 }
 580
 581 static int __init
 582 firmware_class_init(void)
 583 {
 584         int error;
 585         error = class_register(&firmware_class);
 586         if (error) {
 587                 printk(KERN_ERR "%s: class_register failed\n", __FUNCTION__);
 588                 return error;
 589         }
 590         error = class_create_file(&firmware_class, &class_attr_timeout);
 591         if (error) {
 592                 printk(KERN_ERR "%s: class_create_file failed\n",
 593                        __FUNCTION__);
 594                 class_unregister(&firmware_class);
 595         }
 596         return error;
 597
 598 }
 599 static void __exit
 600 firmware_class_exit(void)
 601 {
 602         class_unregister(&firmware_class);
 603 }
 604
 605 module_init(firmware_class_init);
 606 module_exit(firmware_class_exit);
 607
 608 EXPORT_SYMBOL(release_firmware);
 609 EXPORT_SYMBOL(request_firmware);
 610 EXPORT_SYMBOL(request_firmware_nowait);
 611 EXPORT_SYMBOL(register_firmware);