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/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 <asm/semaphore.h>
  19
  20 #include <linux/firmware.h>
  21 #include "base.h"
  22
  23 MODULE_AUTHOR("Manuel Estrada Sainz <ranty@debian.org>");
  24 MODULE_DESCRIPTION("Multi purpose firmware loading support");
  25 MODULE_LICENSE("GPL");
  26
  27 enum {
  28         FW_STATUS_LOADING,
  29         FW_STATUS_DONE,
  30         FW_STATUS_ABORT,
  31         FW_STATUS_READY,
  32         FW_STATUS_READY_NOHOTPLUG,
  33 };
  34
  35 static int loading_timeout = 10;        /* In seconds */
  36
  37 /* fw_lock could be moved to 'struct firmware_priv' but since it is just
  38  * guarding for corner cases a global lock should be OK */
  39 static DECLARE_MUTEX(fw_lock);
  40
  41 struct firmware_priv {
  42         char fw_id[FIRMWARE_NAME_MAX];
  43         struct completion completion;
  44         struct bin_attribute attr_data;
  45         struct firmware *fw;
  46         unsigned long status;
  47         int alloc_size;
  48         struct timer_list timeout;
  49 };
  50
  51 static void
  52 fw_load_abort(struct firmware_priv *fw_priv)
  53 {
  54         set_bit(FW_STATUS_ABORT, &fw_priv->status);
  55         wmb();
  56         complete(&fw_priv->completion);
  57 }
  58
  59 static ssize_t
  60 firmware_timeout_show(struct class *class, char *buf)
  61 {
  62         return sprintf(buf, "%d\n", loading_timeout);
  63 }
  64
  65 /**
  66  * firmware_timeout_store - set number of seconds to wait for firmware
  67  * @class: device class pointer
  68  * @buf: buffer to scan for timeout value
  69  * @count: number of bytes in @buf
  70  *
  71  *      Sets the number of seconds to wait for the firmware.  Once
  72  *      this expires an error will be returned to the driver and no
  73  *      firmware will be provided.
  74  *
  75  *      Note: zero means 'wait forever'.
  76  **/
  77 static ssize_t
  78 firmware_timeout_store(struct class *class, const char *buf, size_t count)
  79 {
  80         loading_timeout = simple_strtol(buf, NULL, 10);
  81         if (loading_timeout < 0)
  82                 loading_timeout = 0;
  83         return count;
  84 }
  85
  86 static CLASS_ATTR(timeout, 0644, firmware_timeout_show, firmware_timeout_store);
  87
  88 static void  fw_class_dev_release(struct class_device *class_dev);
  89 int firmware_class_uevent(struct class_device *dev, char **envp,
  90                            int num_envp, char *buffer, int buffer_size);
  91
  92 static struct class firmware_class = {
  93         .name           = "firmware",
  94         .uevent = firmware_class_uevent,
  95         .release        = fw_class_dev_release,
  96 };
  97
  98 int
  99 firmware_class_uevent(struct class_device *class_dev, char **envp,
 100                        int num_envp, char *buffer, int buffer_size)
 101 {
 102         struct firmware_priv *fw_priv = class_get_devdata(class_dev);
 103         int i = 0, len = 0;
 104
 105         if (!test_bit(FW_STATUS_READY, &fw_priv->status))
 106                 return -ENODEV;
 107
 108         if (add_uevent_var(envp, num_envp, &i, buffer, buffer_size, &len,
 109                            "FIRMWARE=%s", fw_priv->fw_id))
 110                 return -ENOMEM;
 111         if (add_uevent_var(envp, num_envp, &i, buffer, buffer_size, &len,
 112                            "TIMEOUT=%i", loading_timeout))
 113                 return -ENOMEM;
 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         int new_size = fw_priv->alloc_size;
 215
 216         if (min_size <= fw_priv->alloc_size)
 217                 return 0;
 218
 219         new_size = ALIGN(min_size, PAGE_SIZE);
 220         new_data = vmalloc(new_size);
 221         if (!new_data) {
 222                 printk(KERN_ERR "%s: unable to alloc buffer\n", __FUNCTION__);
 223                 /* Make sure that we don't keep incomplete data */
 224                 fw_load_abort(fw_priv);
 225                 return -ENOMEM;
 226         }
 227         fw_priv->alloc_size = new_size;
 228         if (fw_priv->fw->data) {
 229                 memcpy(new_data, fw_priv->fw->data, fw_priv->fw->size);
 230                 vfree(fw_priv->fw->data);
 231         }
 232         fw_priv->fw->data = new_data;
 233         BUG_ON(min_size > fw_priv->alloc_size);
 234         return 0;
 235 }
 236
 237 /**
 238  * firmware_data_write - write method for firmware
 239  * @kobj: kobject for the class_device
 240  * @buffer: buffer being written
 241  * @offset: buffer offset for write in total data store area
 242  * @count: buffer size
 243  *
 244  *      Data written to the 'data' attribute will be later handed to
 245  *      the driver as a firmware image.
 246  **/
 247 static ssize_t
 248 firmware_data_write(struct kobject *kobj,
 249                     char *buffer, loff_t offset, size_t count)
 250 {
 251         struct class_device *class_dev = to_class_dev(kobj);
 252         struct firmware_priv *fw_priv = class_get_devdata(class_dev);
 253         struct firmware *fw;
 254         ssize_t retval;
 255
 256         if (!capable(CAP_SYS_RAWIO))
 257                 return -EPERM;
 258
 259         down(&fw_lock);
 260         fw = fw_priv->fw;
 261         if (!fw || test_bit(FW_STATUS_DONE, &fw_priv->status)) {
 262                 retval = -ENODEV;
 263                 goto out;
 264         }
 265         retval = fw_realloc_buffer(fw_priv, offset + count);
 266         if (retval)
 267                 goto out;
 268
 269         memcpy(fw->data + offset, buffer, count);
 270
 271         fw->size = max_t(size_t, offset + count, fw->size);
 272         retval = count;
 273 out:
 274         up(&fw_lock);
 275         return retval;
 276 }
 277
 278 static struct bin_attribute firmware_attr_data_tmpl = {
 279         .attr = {.name = "data", .mode = 0644, .owner = THIS_MODULE},
 280         .size = 0,
 281         .read = firmware_data_read,
 282         .write = firmware_data_write,
 283 };
 284
 285 static void
 286 fw_class_dev_release(struct class_device *class_dev)
 287 {
 288         struct firmware_priv *fw_priv = class_get_devdata(class_dev);
 289
 290         kfree(fw_priv);
 291         kfree(class_dev);
 292
 293         module_put(THIS_MODULE);
 294 }
 295
 296 static void
 297 firmware_class_timeout(u_long data)
 298 {
 299         struct firmware_priv *fw_priv = (struct firmware_priv *) data;
 300         fw_load_abort(fw_priv);
 301 }
 302
 303 static inline void
 304 fw_setup_class_device_id(struct class_device *class_dev, struct device *dev)
 305 {
 306         /* XXX warning we should watch out for name collisions */
 307         strlcpy(class_dev->class_id, dev->bus_id, BUS_ID_SIZE);
 308 }
 309
 310 static int
 311 fw_register_class_device(struct class_device **class_dev_p,
 312                          const char *fw_name, struct device *device)
 313 {
 314         int retval;
 315         struct firmware_priv *fw_priv = kzalloc(sizeof(*fw_priv),
 316                                                 GFP_KERNEL);
 317         struct class_device *class_dev = kzalloc(sizeof(*class_dev),
 318                                                  GFP_KERNEL);
 319
 320         *class_dev_p = NULL;
 321
 322         if (!fw_priv || !class_dev) {
 323                 printk(KERN_ERR "%s: kmalloc failed\n", __FUNCTION__);
 324                 retval = -ENOMEM;
 325                 goto error_kfree;
 326         }
 327
 328         init_completion(&fw_priv->completion);
 329         fw_priv->attr_data = firmware_attr_data_tmpl;
 330         strlcpy(fw_priv->fw_id, fw_name, FIRMWARE_NAME_MAX);
 331
 332         fw_priv->timeout.function = firmware_class_timeout;
 333         fw_priv->timeout.data = (u_long) fw_priv;
 334         init_timer(&fw_priv->timeout);
 335
 336         fw_setup_class_device_id(class_dev, device);
 337         class_dev->dev = device;
 338         class_dev->class = &firmware_class;
 339         class_set_devdata(class_dev, fw_priv);
 340         retval = class_device_register(class_dev);
 341         if (retval) {
 342                 printk(KERN_ERR "%s: class_device_register failed\n",
 343                        __FUNCTION__);
 344                 goto error_kfree;
 345         }
 346         *class_dev_p = class_dev;
 347         return 0;
 348
 349 error_kfree:
 350         kfree(fw_priv);
 351         kfree(class_dev);
 352         return retval;
 353 }
 354
 355 static int
 356 fw_setup_class_device(struct firmware *fw, struct class_device **class_dev_p,
 357                       const char *fw_name, struct device *device, int uevent)
 358 {
 359         struct class_device *class_dev;
 360         struct firmware_priv *fw_priv;
 361         int retval;
 362
 363         *class_dev_p = NULL;
 364         retval = fw_register_class_device(&class_dev, fw_name, device);
 365         if (retval)
 366                 goto out;
 367
 368         /* Need to pin this module until class device is destroyed */
 369         __module_get(THIS_MODULE);
 370
 371         fw_priv = class_get_devdata(class_dev);
 372
 373         fw_priv->fw = fw;
 374         retval = sysfs_create_bin_file(&class_dev->kobj, &fw_priv->attr_data);
 375         if (retval) {
 376                 printk(KERN_ERR "%s: sysfs_create_bin_file failed\n",
 377                        __FUNCTION__);
 378                 goto error_unreg;
 379         }
 380
 381         retval = class_device_create_file(class_dev,
 382                                           &class_device_attr_loading);
 383         if (retval) {
 384                 printk(KERN_ERR "%s: class_device_create_file failed\n",
 385                        __FUNCTION__);
 386                 goto error_unreg;
 387         }
 388
 389         if (uevent)
 390                 set_bit(FW_STATUS_READY, &fw_priv->status);
 391         else
 392                 set_bit(FW_STATUS_READY_NOHOTPLUG, &fw_priv->status);
 393         *class_dev_p = class_dev;
 394         goto out;
 395
 396 error_unreg:
 397         class_device_unregister(class_dev);
 398 out:
 399         return retval;
 400 }
 401
 402 static int
 403 _request_firmware(const struct firmware **firmware_p, const char *name,
 404                  struct device *device, int uevent)
 405 {
 406         struct class_device *class_dev;
 407         struct firmware_priv *fw_priv;
 408         struct firmware *firmware;
 409         int retval;
 410
 411         if (!firmware_p)
 412                 return -EINVAL;
 413
 414         *firmware_p = firmware = kzalloc(sizeof(*firmware), GFP_KERNEL);
 415         if (!firmware) {
 416                 printk(KERN_ERR "%s: kmalloc(struct firmware) failed\n",
 417                        __FUNCTION__);
 418                 retval = -ENOMEM;
 419                 goto out;
 420         }
 421
 422         retval = fw_setup_class_device(firmware, &class_dev, name, device,
 423                                        uevent);
 424         if (retval)
 425                 goto error_kfree_fw;
 426
 427         fw_priv = class_get_devdata(class_dev);
 428
 429         if (uevent) {
 430                 if (loading_timeout > 0) {
 431                         fw_priv->timeout.expires = jiffies + loading_timeout * HZ;
 432                         add_timer(&fw_priv->timeout);
 433                 }
 434
 435                 kobject_uevent(&class_dev->kobj, KOBJ_ADD);
 436                 wait_for_completion(&fw_priv->completion);
 437                 set_bit(FW_STATUS_DONE, &fw_priv->status);
 438                 del_timer_sync(&fw_priv->timeout);
 439         } else
 440                 wait_for_completion(&fw_priv->completion);
 441
 442         down(&fw_lock);
 443         if (!fw_priv->fw->size || test_bit(FW_STATUS_ABORT, &fw_priv->status)) {
 444                 retval = -ENOENT;
 445                 release_firmware(fw_priv->fw);
 446                 *firmware_p = NULL;
 447         }
 448         fw_priv->fw = NULL;
 449         up(&fw_lock);
 450         class_device_unregister(class_dev);
 451         goto out;
 452
 453 error_kfree_fw:
 454         kfree(firmware);
 455         *firmware_p = NULL;
 456 out:
 457         return retval;
 458 }
 459
 460 /**
 461  * request_firmware: - send firmware request and wait for it
 462  * @firmware_p: pointer to firmware image
 463  * @name: name of firmware file
 464  * @device: device for which firmware is being loaded
 465  *
 466  *      @firmware_p will be used to return a firmware image by the name
 467  *      of @name for device @device.
 468  *
 469  *      Should be called from user context where sleeping is allowed.
 470  *
 471  *      @name will be used as $FIRMWARE in the uevent environment and
 472  *      should be distinctive enough not to be confused with any other
 473  *      firmware image for this or any other device.
 474  **/
 475 int
 476 request_firmware(const struct firmware **firmware_p, const char *name,
 477                  struct device *device)
 478 {
 479         int uevent = 1;
 480         return _request_firmware(firmware_p, name, device, uevent);
 481 }
 482
 483 /**
 484  * release_firmware: - release the resource associated with a firmware image
 485  * @fw: firmware resource to release
 486  **/
 487 void
 488 release_firmware(const struct firmware *fw)
 489 {
 490         if (fw) {
 491                 vfree(fw->data);
 492                 kfree(fw);
 493         }
 494 }
 495
 496 /**
 497  * register_firmware: - provide a firmware image for later usage
 498  * @name: name of firmware image file
 499  * @data: buffer pointer for the firmware image
 500  * @size: size of the data buffer area
 501  *
 502  *      Make sure that @data will be available by requesting firmware @name.
 503  *
 504  *      Note: This will not be possible until some kind of persistence
 505  *      is available.
 506  **/
 507 void
 508 register_firmware(const char *name, const u8 *data, size_t size)
 509 {
 510         /* This is meaningless without firmware caching, so until we
 511          * decide if firmware caching is reasonable just leave it as a
 512          * noop */
 513 }
 514
 515 /* Async support */
 516 struct firmware_work {
 517         struct work_struct work;
 518         struct module *module;
 519         const char *name;
 520         struct device *device;
 521         void *context;
 522         void (*cont)(const struct firmware *fw, void *context);
 523         int uevent;
 524 };
 525
 526 static int
 527 request_firmware_work_func(void *arg)
 528 {
 529         struct firmware_work *fw_work = arg;
 530         const struct firmware *fw;
 531         int ret;
 532         if (!arg) {
 533                 WARN_ON(1);
 534                 return 0;
 535         }
 536         daemonize("%s/%s", "firmware", fw_work->name);
 537         ret = _request_firmware(&fw, fw_work->name, fw_work->device,
 538                 fw_work->uevent);
 539         if (ret < 0)
 540                 fw_work->cont(NULL, fw_work->context);
 541         else {
 542                 fw_work->cont(fw, fw_work->context);
 543                 release_firmware(fw);
 544         }
 545         module_put(fw_work->module);
 546         kfree(fw_work);
 547         return ret;
 548 }
 549
 550 /**
 551  * request_firmware_nowait: asynchronous version of request_firmware
 552  * @module: module requesting the firmware
 553  * @uevent: sends uevent to copy the firmware image if this flag
 554  *      is non-zero else the firmware copy must be done manually.
 555  * @name: name of firmware file
 556  * @device: device for which firmware is being loaded
 557  * @context: will be passed over to @cont, and
 558  *      @fw may be %NULL if firmware request fails.
 559  * @cont: function will be called asynchronously when the firmware
 560  *      request is over.
 561  *
 562  *      Asynchronous variant of request_firmware() for contexts where
 563  *      it is not possible to sleep.
 564  **/
 565 int
 566 request_firmware_nowait(
 567         struct module *module, int uevent,
 568         const char *name, struct device *device, void *context,
 569         void (*cont)(const struct firmware *fw, void *context))
 570 {
 571         struct firmware_work *fw_work = kmalloc(sizeof (struct firmware_work),
 572                                                 GFP_ATOMIC);
 573         int ret;
 574
 575         if (!fw_work)
 576                 return -ENOMEM;
 577         if (!try_module_get(module)) {
 578                 kfree(fw_work);
 579                 return -EFAULT;
 580         }
 581
 582         *fw_work = (struct firmware_work) {
 583                 .module = module,
 584                 .name = name,
 585                 .device = device,
 586                 .context = context,
 587                 .cont = cont,
 588                 .uevent = uevent,
 589         };
 590
 591         ret = kernel_thread(request_firmware_work_func, fw_work,
 592                             CLONE_FS | CLONE_FILES);
 593
 594         if (ret < 0) {
 595                 fw_work->cont(NULL, fw_work->context);
 596                 module_put(fw_work->module);
 597                 kfree(fw_work);
 598                 return ret;
 599         }
 600         return 0;
 601 }
 602
 603 static int __init
 604 firmware_class_init(void)
 605 {
 606         int error;
 607         error = class_register(&firmware_class);
 608         if (error) {
 609                 printk(KERN_ERR "%s: class_register failed\n", __FUNCTION__);
 610                 return error;
 611         }
 612         error = class_create_file(&firmware_class, &class_attr_timeout);
 613         if (error) {
 614                 printk(KERN_ERR "%s: class_create_file failed\n",
 615                        __FUNCTION__);
 616                 class_unregister(&firmware_class);
 617         }
 618         return error;
 619
 620 }
 621 static void __exit
 622 firmware_class_exit(void)
 623 {
 624         class_unregister(&firmware_class);
 625 }
 626
 627 module_init(firmware_class_init);
 628 module_exit(firmware_class_exit);
 629
 630 EXPORT_SYMBOL(release_firmware);
 631 EXPORT_SYMBOL(request_firmware);
 632 EXPORT_SYMBOL(request_firmware_nowait);
 633 EXPORT_SYMBOL(register_firmware);