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 - set number of seconds to wait for firmware
  66  * @class: device class pointer
  67  * @buf: buffer to scan for timeout value
  68  * @count: number of bytes in @buf
  69  *
  70  *      Sets the number of seconds to wait for the firmware.  Once
  71  *      this expires an error will be returned to the driver and no
  72  *      firmware will be provided.
  73  *
  74  *      Note: zero means 'wait forever'.
  75  **/
  76 static ssize_t
  77 firmware_timeout_store(struct class *class, const char *buf, size_t count)
  78 {
  79         loading_timeout = simple_strtol(buf, NULL, 10);
  80         if (loading_timeout < 0)
  81                 loading_timeout = 0;
  82         return count;
  83 }
  84
  85 static CLASS_ATTR(timeout, 0644, firmware_timeout_show, firmware_timeout_store);
  86
  87 static void  fw_class_dev_release(struct class_device *class_dev);
  88 int firmware_class_hotplug(struct class_device *dev, char **envp,
  89                            int num_envp, char *buffer, int buffer_size);
  90
  91 static struct class firmware_class = {
  92         .name           = "firmware",
  93         .hotplug        = firmware_class_hotplug,
  94         .release        = fw_class_dev_release,
  95 };
  96
  97 int
  98 firmware_class_hotplug(struct class_device *class_dev, char **envp,
  99                        int num_envp, char *buffer, int buffer_size)
 100 {
 101         struct firmware_priv *fw_priv = class_get_devdata(class_dev);
 102         int i = 0, len = 0;
 103
 104         if (!test_bit(FW_STATUS_READY, &fw_priv->status))
 105                 return -ENODEV;
 106
 107         if (add_hotplug_env_var(envp, num_envp, &i, buffer, buffer_size, &len,
 108                         "FIRMWARE=%s", fw_priv->fw_id))
 109                 return -ENOMEM;
 110         if (add_hotplug_env_var(envp, num_envp, &i, buffer, buffer_size, &len,
 111                         "TIMEOUT=%i", loading_timeout))
 112                 return -ENOMEM;
 113
 114         envp[i] = NULL;
 115
 116         return 0;
 117 }
 118
 119 static ssize_t
 120 firmware_loading_show(struct class_device *class_dev, char *buf)
 121 {
 122         struct firmware_priv *fw_priv = class_get_devdata(class_dev);
 123         int loading = test_bit(FW_STATUS_LOADING, &fw_priv->status);
 124         return sprintf(buf, "%d\n", loading);
 125 }
 126
 127 /**
 128  * firmware_loading_store - set value in the 'loading' control file
 129  * @class_dev: class_device pointer
 130  * @buf: buffer to scan for loading control value
 131  * @count: number of bytes in @buf
 132  *
 133  *      The relevant values are:
 134  *
 135  *       1: Start a load, discarding any previous partial load.
 136  *       0: Conclude the load and hand the data to the driver code.
 137  *      -1: Conclude the load with an error and discard any written data.
 138  **/
 139 static ssize_t
 140 firmware_loading_store(struct class_device *class_dev,
 141                        const char *buf, size_t count)
 142 {
 143         struct firmware_priv *fw_priv = class_get_devdata(class_dev);
 144         int loading = simple_strtol(buf, NULL, 10);
 145
 146         switch (loading) {
 147         case 1:
 148                 down(&fw_lock);
 149                 if (!fw_priv->fw) {
 150                         up(&fw_lock);
 151                         break;
 152                 }
 153                 vfree(fw_priv->fw->data);
 154                 fw_priv->fw->data = NULL;
 155                 fw_priv->fw->size = 0;
 156                 fw_priv->alloc_size = 0;
 157                 set_bit(FW_STATUS_LOADING, &fw_priv->status);
 158                 up(&fw_lock);
 159                 break;
 160         case 0:
 161                 if (test_bit(FW_STATUS_LOADING, &fw_priv->status)) {
 162                         complete(&fw_priv->completion);
 163                         clear_bit(FW_STATUS_LOADING, &fw_priv->status);
 164                         break;
 165                 }
 166                 /* fallthrough */
 167         default:
 168                 printk(KERN_ERR "%s: unexpected value (%d)\n", __FUNCTION__,
 169                        loading);
 170                 /* fallthrough */
 171         case -1:
 172                 fw_load_abort(fw_priv);
 173                 break;
 174         }
 175
 176         return count;
 177 }
 178
 179 static CLASS_DEVICE_ATTR(loading, 0644,
 180                         firmware_loading_show, firmware_loading_store);
 181
 182 static ssize_t
 183 firmware_data_read(struct kobject *kobj,
 184                    char *buffer, loff_t offset, size_t count)
 185 {
 186         struct class_device *class_dev = to_class_dev(kobj);
 187         struct firmware_priv *fw_priv = class_get_devdata(class_dev);
 188         struct firmware *fw;
 189         ssize_t ret_count = count;
 190
 191         down(&fw_lock);
 192         fw = fw_priv->fw;
 193         if (!fw || test_bit(FW_STATUS_DONE, &fw_priv->status)) {
 194                 ret_count = -ENODEV;
 195                 goto out;
 196         }
 197         if (offset > fw->size) {
 198                 ret_count = 0;
 199                 goto out;
 200         }
 201         if (offset + ret_count > fw->size)
 202                 ret_count = fw->size - offset;
 203
 204         memcpy(buffer, fw->data + offset, ret_count);
 205 out:
 206         up(&fw_lock);
 207         return ret_count;
 208 }
 209
 210 static int
 211 fw_realloc_buffer(struct firmware_priv *fw_priv, int min_size)
 212 {
 213         u8 *new_data;
 214
 215         if (min_size <= fw_priv->alloc_size)
 216                 return 0;
 217
 218         new_data = vmalloc(fw_priv->alloc_size + PAGE_SIZE);
 219         if (!new_data) {
 220                 printk(KERN_ERR "%s: unable to alloc buffer\n", __FUNCTION__);
 221                 /* Make sure that we don't keep incomplete data */
 222                 fw_load_abort(fw_priv);
 223                 return -ENOMEM;
 224         }
 225         fw_priv->alloc_size += PAGE_SIZE;
 226         if (fw_priv->fw->data) {
 227                 memcpy(new_data, fw_priv->fw->data, fw_priv->fw->size);
 228                 vfree(fw_priv->fw->data);
 229         }
 230         fw_priv->fw->data = new_data;
 231         BUG_ON(min_size > fw_priv->alloc_size);
 232         return 0;
 233 }
 234
 235 /**
 236  * firmware_data_write - write method for firmware
 237  * @kobj: kobject for the class_device
 238  * @buffer: buffer being written
 239  * @offset: buffer offset for write in total data store area
 240  * @count: buffer size
 241  *
 242  *      Data written to the 'data' attribute will be later handed to
 243  *      the driver as a firmware image.
 244  **/
 245 static ssize_t
 246 firmware_data_write(struct kobject *kobj,
 247                     char *buffer, loff_t offset, size_t count)
 248 {
 249         struct class_device *class_dev = to_class_dev(kobj);
 250         struct firmware_priv *fw_priv = class_get_devdata(class_dev);
 251         struct firmware *fw;
 252         ssize_t retval;
 253
 254         if (!capable(CAP_SYS_RAWIO))
 255                 return -EPERM;
 256
 257         down(&fw_lock);
 258         fw = fw_priv->fw;
 259         if (!fw || test_bit(FW_STATUS_DONE, &fw_priv->status)) {
 260                 retval = -ENODEV;
 261                 goto out;
 262         }
 263         retval = fw_realloc_buffer(fw_priv, offset + count);
 264         if (retval)
 265                 goto out;
 266
 267         memcpy(fw->data + offset, buffer, count);
 268
 269         fw->size = max_t(size_t, offset + count, fw->size);
 270         retval = count;
 271 out:
 272         up(&fw_lock);
 273         return retval;
 274 }
 275
 276 static struct bin_attribute firmware_attr_data_tmpl = {
 277         .attr = {.name = "data", .mode = 0644, .owner = THIS_MODULE},
 278         .size = 0,
 279         .read = firmware_data_read,
 280         .write = firmware_data_write,
 281 };
 282
 283 static void
 284 fw_class_dev_release(struct class_device *class_dev)
 285 {
 286         struct firmware_priv *fw_priv = class_get_devdata(class_dev);
 287
 288         kfree(fw_priv);
 289         kfree(class_dev);
 290
 291         module_put(THIS_MODULE);
 292 }
 293
 294 static void
 295 firmware_class_timeout(u_long data)
 296 {
 297         struct firmware_priv *fw_priv = (struct firmware_priv *) data;
 298         fw_load_abort(fw_priv);
 299 }
 300
 301 static inline void
 302 fw_setup_class_device_id(struct class_device *class_dev, struct device *dev)
 303 {
 304         /* XXX warning we should watch out for name collisions */
 305         strlcpy(class_dev->class_id, dev->bus_id, BUS_ID_SIZE);
 306 }
 307
 308 static int
 309 fw_register_class_device(struct class_device **class_dev_p,
 310                          const char *fw_name, struct device *device)
 311 {
 312         int retval;
 313         struct firmware_priv *fw_priv = kzalloc(sizeof(*fw_priv),
 314                                                 GFP_KERNEL);
 315         struct class_device *class_dev = kzalloc(sizeof(*class_dev),
 316                                                  GFP_KERNEL);
 317
 318         *class_dev_p = NULL;
 319
 320         if (!fw_priv || !class_dev) {
 321                 printk(KERN_ERR "%s: kmalloc failed\n", __FUNCTION__);
 322                 retval = -ENOMEM;
 323                 goto error_kfree;
 324         }
 325
 326         init_completion(&fw_priv->completion);
 327         fw_priv->attr_data = firmware_attr_data_tmpl;
 328         strlcpy(fw_priv->fw_id, fw_name, FIRMWARE_NAME_MAX);
 329
 330         fw_priv->timeout.function = firmware_class_timeout;
 331         fw_priv->timeout.data = (u_long) fw_priv;
 332         init_timer(&fw_priv->timeout);
 333
 334         fw_setup_class_device_id(class_dev, device);
 335         class_dev->dev = device;
 336         class_dev->class = &firmware_class;
 337         class_set_devdata(class_dev, fw_priv);
 338         retval = class_device_register(class_dev);
 339         if (retval) {
 340                 printk(KERN_ERR "%s: class_device_register failed\n",
 341                        __FUNCTION__);
 342                 goto error_kfree;
 343         }
 344         *class_dev_p = class_dev;
 345         return 0;
 346
 347 error_kfree:
 348         kfree(fw_priv);
 349         kfree(class_dev);
 350         return retval;
 351 }
 352
 353 static int
 354 fw_setup_class_device(struct firmware *fw, struct class_device **class_dev_p,
 355                       const char *fw_name, struct device *device, int hotplug)
 356 {
 357         struct class_device *class_dev;
 358         struct firmware_priv *fw_priv;
 359         int retval;
 360
 361         *class_dev_p = NULL;
 362         retval = fw_register_class_device(&class_dev, fw_name, device);
 363         if (retval)
 364                 goto out;
 365
 366         /* Need to pin this module until class device is destroyed */
 367         __module_get(THIS_MODULE);
 368
 369         fw_priv = class_get_devdata(class_dev);
 370
 371         fw_priv->fw = fw;
 372         retval = sysfs_create_bin_file(&class_dev->kobj, &fw_priv->attr_data);
 373         if (retval) {
 374                 printk(KERN_ERR "%s: sysfs_create_bin_file failed\n",
 375                        __FUNCTION__);
 376                 goto error_unreg;
 377         }
 378
 379         retval = class_device_create_file(class_dev,
 380                                           &class_device_attr_loading);
 381         if (retval) {
 382                 printk(KERN_ERR "%s: class_device_create_file failed\n",
 383                        __FUNCTION__);
 384                 goto error_unreg;
 385         }
 386
 387         if (hotplug)
 388                 set_bit(FW_STATUS_READY, &fw_priv->status);
 389         else
 390                 set_bit(FW_STATUS_READY_NOHOTPLUG, &fw_priv->status);
 391         *class_dev_p = class_dev;
 392         goto out;
 393
 394 error_unreg:
 395         class_device_unregister(class_dev);
 396 out:
 397         return retval;
 398 }
 399
 400 static int
 401 _request_firmware(const struct firmware **firmware_p, const char *name,
 402                  struct device *device, int hotplug)
 403 {
 404         struct class_device *class_dev;
 405         struct firmware_priv *fw_priv;
 406         struct firmware *firmware;
 407         int retval;
 408
 409         if (!firmware_p)
 410                 return -EINVAL;
 411
 412         *firmware_p = firmware = kzalloc(sizeof(*firmware), GFP_KERNEL);
 413         if (!firmware) {
 414                 printk(KERN_ERR "%s: kmalloc(struct firmware) failed\n",
 415                        __FUNCTION__);
 416                 retval = -ENOMEM;
 417                 goto out;
 418         }
 419
 420         retval = fw_setup_class_device(firmware, &class_dev, name, device,
 421                 hotplug);
 422         if (retval)
 423                 goto error_kfree_fw;
 424
 425         fw_priv = class_get_devdata(class_dev);
 426
 427         if (hotplug) {
 428                 if (loading_timeout > 0) {
 429                         fw_priv->timeout.expires = jiffies + loading_timeout * HZ;
 430                         add_timer(&fw_priv->timeout);
 431                 }
 432
 433                 kobject_hotplug(&class_dev->kobj, KOBJ_ADD);
 434                 wait_for_completion(&fw_priv->completion);
 435                 set_bit(FW_STATUS_DONE, &fw_priv->status);
 436                 del_timer_sync(&fw_priv->timeout);
 437         } else
 438                 wait_for_completion(&fw_priv->completion);
 439
 440         down(&fw_lock);
 441         if (!fw_priv->fw->size || test_bit(FW_STATUS_ABORT, &fw_priv->status)) {
 442                 retval = -ENOENT;
 443                 release_firmware(fw_priv->fw);
 444                 *firmware_p = NULL;
 445         }
 446         fw_priv->fw = NULL;
 447         up(&fw_lock);
 448         class_device_unregister(class_dev);
 449         goto out;
 450
 451 error_kfree_fw:
 452         kfree(firmware);
 453         *firmware_p = NULL;
 454 out:
 455         return retval;
 456 }
 457
 458 /**
 459  * request_firmware: - request firmware to hotplug and wait for it
 460  * @firmware_p: pointer to firmware image
 461  * @name: name of firmware file
 462  * @device: device for which firmware is being loaded
 463  *
 464  *      @firmware_p will be used to return a firmware image by the name
 465  *      of @name for device @device.
 466  *
 467  *      Should be called from user context where sleeping is allowed.
 468  *
 469  *      @name will be used as $FIRMWARE in the hotplug environment and
 470  *      should be distinctive enough not to be confused with any other
 471  *      firmware image for this or any other device.
 472  **/
 473 int
 474 request_firmware(const struct firmware **firmware_p, const char *name,
 475                  struct device *device)
 476 {
 477         int hotplug = 1;
 478         return _request_firmware(firmware_p, name, device, hotplug);
 479 }
 480
 481 /**
 482  * release_firmware: - release the resource associated with a firmware image
 483  * @fw: firmware resource to release
 484  **/
 485 void
 486 release_firmware(const struct firmware *fw)
 487 {
 488         if (fw) {
 489                 vfree(fw->data);
 490                 kfree(fw);
 491         }
 492 }
 493
 494 /**
 495  * register_firmware: - provide a firmware image for later usage
 496  * @name: name of firmware image file
 497  * @data: buffer pointer for the firmware image
 498  * @size: size of the data buffer area
 499  *
 500  *      Make sure that @data will be available by requesting firmware @name.
 501  *
 502  *      Note: This will not be possible until some kind of persistence
 503  *      is available.
 504  **/
 505 void
 506 register_firmware(const char *name, const u8 *data, size_t size)
 507 {
 508         /* This is meaningless without firmware caching, so until we
 509          * decide if firmware caching is reasonable just leave it as a
 510          * noop */
 511 }
 512
 513 /* Async support */
 514 struct firmware_work {
 515         struct work_struct work;
 516         struct module *module;
 517         const char *name;
 518         struct device *device;
 519         void *context;
 520         void (*cont)(const struct firmware *fw, void *context);
 521         int hotplug;
 522 };
 523
 524 static int
 525 request_firmware_work_func(void *arg)
 526 {
 527         struct firmware_work *fw_work = arg;
 528         const struct firmware *fw;
 529         if (!arg) {
 530                 WARN_ON(1);
 531                 return 0;
 532         }
 533         daemonize("%s/%s", "firmware", fw_work->name);
 534         _request_firmware(&fw, fw_work->name, fw_work->device,
 535                 fw_work->hotplug);
 536         fw_work->cont(fw, fw_work->context);
 537         release_firmware(fw);
 538         module_put(fw_work->module);
 539         kfree(fw_work);
 540         return 0;
 541 }
 542
 543 /**
 544  * request_firmware_nowait: asynchronous version of request_firmware
 545  * @module: module requesting the firmware
 546  * @hotplug: invokes hotplug event to copy the firmware image if this flag
 547  *      is non-zero else the firmware copy must be done manually.
 548  * @name: name of firmware file
 549  * @device: device for which firmware is being loaded
 550  * @context: will be passed over to @cont, and
 551  *      @fw may be %NULL if firmware request fails.
 552  * @cont: function will be called asynchronously when the firmware
 553  *      request is over.
 554  *
 555  *      Asynchronous variant of request_firmware() for contexts where
 556  *      it is not possible to sleep.
 557  **/
 558 int
 559 request_firmware_nowait(
 560         struct module *module, int hotplug,
 561         const char *name, struct device *device, void *context,
 562         void (*cont)(const struct firmware *fw, void *context))
 563 {
 564         struct firmware_work *fw_work = kmalloc(sizeof (struct firmware_work),
 565                                                 GFP_ATOMIC);
 566         int ret;
 567
 568         if (!fw_work)
 569                 return -ENOMEM;
 570         if (!try_module_get(module)) {
 571                 kfree(fw_work);
 572                 return -EFAULT;
 573         }
 574
 575         *fw_work = (struct firmware_work) {
 576                 .module = module,
 577                 .name = name,
 578                 .device = device,
 579                 .context = context,
 580                 .cont = cont,
 581                 .hotplug = hotplug,
 582         };
 583
 584         ret = kernel_thread(request_firmware_work_func, fw_work,
 585                             CLONE_FS | CLONE_FILES);
 586
 587         if (ret < 0) {
 588                 fw_work->cont(NULL, fw_work->context);
 589                 return ret;
 590         }
 591         return 0;
 592 }
 593
 594 static int __init
 595 firmware_class_init(void)
 596 {
 597         int error;
 598         error = class_register(&firmware_class);
 599         if (error) {
 600                 printk(KERN_ERR "%s: class_register failed\n", __FUNCTION__);
 601                 return error;
 602         }
 603         error = class_create_file(&firmware_class, &class_attr_timeout);
 604         if (error) {
 605                 printk(KERN_ERR "%s: class_create_file failed\n",
 606                        __FUNCTION__);
 607                 class_unregister(&firmware_class);
 608         }
 609         return error;
 610
 611 }
 612 static void __exit
 613 firmware_class_exit(void)
 614 {
 615         class_unregister(&firmware_class);
 616 }
 617
 618 module_init(firmware_class_init);
 619 module_exit(firmware_class_exit);
 620
 621 EXPORT_SYMBOL(release_firmware);
 622 EXPORT_SYMBOL(request_firmware);
 623 EXPORT_SYMBOL(request_firmware_nowait);
 624 EXPORT_SYMBOL(register_firmware);