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 <linux/mutex.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 DEFINE_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
  90 static int firmware_class_uevent(struct class_device *class_dev, char **envp,
  91                                  int num_envp, char *buffer, int buffer_size)
  92 {
  93         struct firmware_priv *fw_priv = class_get_devdata(class_dev);
  94         int i = 0, len = 0;
  95
  96         if (!test_bit(FW_STATUS_READY, &fw_priv->status))
  97                 return -ENODEV;
  98
  99         if (add_uevent_var(envp, num_envp, &i, buffer, buffer_size, &len,
 100                            "FIRMWARE=%s", fw_priv->fw_id))
 101                 return -ENOMEM;
 102         if (add_uevent_var(envp, num_envp, &i, buffer, buffer_size, &len,
 103                            "TIMEOUT=%i", loading_timeout))
 104                 return -ENOMEM;
 105         envp[i] = NULL;
 106
 107         return 0;
 108 }
 109
 110 static struct class firmware_class = {
 111         .name           = "firmware",
 112         .uevent         = firmware_class_uevent,
 113         .release        = fw_class_dev_release,
 114 };
 115
 116 static ssize_t
 117 firmware_loading_show(struct class_device *class_dev, char *buf)
 118 {
 119         struct firmware_priv *fw_priv = class_get_devdata(class_dev);
 120         int loading = test_bit(FW_STATUS_LOADING, &fw_priv->status);
 121         return sprintf(buf, "%d\n", loading);
 122 }
 123
 124 /**
 125  * firmware_loading_store - set value in the 'loading' control file
 126  * @class_dev: class_device pointer
 127  * @buf: buffer to scan for loading control value
 128  * @count: number of bytes in @buf
 129  *
 130  *      The relevant values are:
 131  *
 132  *       1: Start a load, discarding any previous partial load.
 133  *       0: Conclude the load and hand the data to the driver code.
 134  *      -1: Conclude the load with an error and discard any written data.
 135  **/
 136 static ssize_t
 137 firmware_loading_store(struct class_device *class_dev,
 138                        const char *buf, size_t count)
 139 {
 140         struct firmware_priv *fw_priv = class_get_devdata(class_dev);
 141         int loading = simple_strtol(buf, NULL, 10);
 142
 143         switch (loading) {
 144         case 1:
 145                 mutex_lock(&fw_lock);
 146                 if (!fw_priv->fw) {
 147                         mutex_unlock(&fw_lock);
 148                         break;
 149                 }
 150                 vfree(fw_priv->fw->data);
 151                 fw_priv->fw->data = NULL;
 152                 fw_priv->fw->size = 0;
 153                 fw_priv->alloc_size = 0;
 154                 set_bit(FW_STATUS_LOADING, &fw_priv->status);
 155                 mutex_unlock(&fw_lock);
 156                 break;
 157         case 0:
 158                 if (test_bit(FW_STATUS_LOADING, &fw_priv->status)) {
 159                         complete(&fw_priv->completion);
 160                         clear_bit(FW_STATUS_LOADING, &fw_priv->status);
 161                         break;
 162                 }
 163                 /* fallthrough */
 164         default:
 165                 printk(KERN_ERR "%s: unexpected value (%d)\n", __FUNCTION__,
 166                        loading);
 167                 /* fallthrough */
 168         case -1:
 169                 fw_load_abort(fw_priv);
 170                 break;
 171         }
 172
 173         return count;
 174 }
 175
 176 static CLASS_DEVICE_ATTR(loading, 0644,
 177                         firmware_loading_show, firmware_loading_store);
 178
 179 static ssize_t
 180 firmware_data_read(struct kobject *kobj,
 181                    char *buffer, loff_t offset, size_t count)
 182 {
 183         struct class_device *class_dev = to_class_dev(kobj);
 184         struct firmware_priv *fw_priv = class_get_devdata(class_dev);
 185         struct firmware *fw;
 186         ssize_t ret_count = 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         if (offset > fw->size) {
 195                 ret_count = 0;
 196                 goto out;
 197         }
 198         if (offset + ret_count > fw->size)
 199                 ret_count = fw->size - offset;
 200
 201         memcpy(buffer, fw->data + offset, ret_count);
 202 out:
 203         mutex_unlock(&fw_lock);
 204         return ret_count;
 205 }
 206
 207 static int
 208 fw_realloc_buffer(struct firmware_priv *fw_priv, int min_size)
 209 {
 210         u8 *new_data;
 211         int new_size = fw_priv->alloc_size;
 212
 213         if (min_size <= fw_priv->alloc_size)
 214                 return 0;
 215
 216         new_size = ALIGN(min_size, PAGE_SIZE);
 217         new_data = vmalloc(new_size);
 218         if (!new_data) {
 219                 printk(KERN_ERR "%s: unable to alloc buffer\n", __FUNCTION__);
 220                 /* Make sure that we don't keep incomplete data */
 221                 fw_load_abort(fw_priv);
 222                 return -ENOMEM;
 223         }
 224         fw_priv->alloc_size = new_size;
 225         if (fw_priv->fw->data) {
 226                 memcpy(new_data, fw_priv->fw->data, fw_priv->fw->size);
 227                 vfree(fw_priv->fw->data);
 228         }
 229         fw_priv->fw->data = new_data;
 230         BUG_ON(min_size > fw_priv->alloc_size);
 231         return 0;
 232 }
 233
 234 /**
 235  * firmware_data_write - write method for firmware
 236  * @kobj: kobject for the class_device
 237  * @buffer: buffer being written
 238  * @offset: buffer offset for write in total data store area
 239  * @count: buffer size
 240  *
 241  *      Data written to the 'data' attribute will be later handed to
 242  *      the driver as a firmware image.
 243  **/
 244 static ssize_t
 245 firmware_data_write(struct kobject *kobj,
 246                     char *buffer, loff_t offset, size_t count)
 247 {
 248         struct class_device *class_dev = to_class_dev(kobj);
 249         struct firmware_priv *fw_priv = class_get_devdata(class_dev);
 250         struct firmware *fw;
 251         ssize_t retval;
 252
 253         if (!capable(CAP_SYS_RAWIO))
 254                 return -EPERM;
 255
 256         mutex_lock(&fw_lock);
 257         fw = fw_priv->fw;
 258         if (!fw || test_bit(FW_STATUS_DONE, &fw_priv->status)) {
 259                 retval = -ENODEV;
 260                 goto out;
 261         }
 262         retval = fw_realloc_buffer(fw_priv, offset + count);
 263         if (retval)
 264                 goto out;
 265
 266         memcpy(fw->data + offset, buffer, count);
 267
 268         fw->size = max_t(size_t, offset + count, fw->size);
 269         retval = count;
 270 out:
 271         mutex_unlock(&fw_lock);
 272         return retval;
 273 }
 274
 275 static struct bin_attribute firmware_attr_data_tmpl = {
 276         .attr = {.name = "data", .mode = 0644, .owner = THIS_MODULE},
 277         .size = 0,
 278         .read = firmware_data_read,
 279         .write = firmware_data_write,
 280 };
 281
 282 static void
 283 fw_class_dev_release(struct class_device *class_dev)
 284 {
 285         struct firmware_priv *fw_priv = class_get_devdata(class_dev);
 286
 287         kfree(fw_priv);
 288         kfree(class_dev);
 289
 290         module_put(THIS_MODULE);
 291 }
 292
 293 static void
 294 firmware_class_timeout(u_long data)
 295 {
 296         struct firmware_priv *fw_priv = (struct firmware_priv *) data;
 297         fw_load_abort(fw_priv);
 298 }
 299
 300 static inline void
 301 fw_setup_class_device_id(struct class_device *class_dev, struct device *dev)
 302 {
 303         /* XXX warning we should watch out for name collisions */
 304         strlcpy(class_dev->class_id, dev->bus_id, BUS_ID_SIZE);
 305 }
 306
 307 static int
 308 fw_register_class_device(struct class_device **class_dev_p,
 309                          const char *fw_name, struct device *device)
 310 {
 311         int retval;
 312         struct firmware_priv *fw_priv = kzalloc(sizeof(*fw_priv),
 313                                                 GFP_KERNEL);
 314         struct class_device *class_dev = kzalloc(sizeof(*class_dev),
 315                                                  GFP_KERNEL);
 316
 317         *class_dev_p = NULL;
 318
 319         if (!fw_priv || !class_dev) {
 320                 printk(KERN_ERR "%s: kmalloc failed\n", __FUNCTION__);
 321                 retval = -ENOMEM;
 322                 goto error_kfree;
 323         }
 324
 325         init_completion(&fw_priv->completion);
 326         fw_priv->attr_data = firmware_attr_data_tmpl;
 327         strlcpy(fw_priv->fw_id, fw_name, FIRMWARE_NAME_MAX);
 328
 329         fw_priv->timeout.function = firmware_class_timeout;
 330         fw_priv->timeout.data = (u_long) fw_priv;
 331         init_timer(&fw_priv->timeout);
 332
 333         fw_setup_class_device_id(class_dev, device);
 334         class_dev->dev = device;
 335         class_dev->class = &firmware_class;
 336         class_set_devdata(class_dev, fw_priv);
 337         retval = class_device_register(class_dev);
 338         if (retval) {
 339                 printk(KERN_ERR "%s: class_device_register failed\n",
 340                        __FUNCTION__);
 341                 goto error_kfree;
 342         }
 343         *class_dev_p = class_dev;
 344         return 0;
 345
 346 error_kfree:
 347         kfree(fw_priv);
 348         kfree(class_dev);
 349         return retval;
 350 }
 351
 352 static int
 353 fw_setup_class_device(struct firmware *fw, struct class_device **class_dev_p,
 354                       const char *fw_name, struct device *device, int uevent)
 355 {
 356         struct class_device *class_dev;
 357         struct firmware_priv *fw_priv;
 358         int retval;
 359
 360         *class_dev_p = NULL;
 361         retval = fw_register_class_device(&class_dev, fw_name, device);
 362         if (retval)
 363                 goto out;
 364
 365         /* Need to pin this module until class device is destroyed */
 366         __module_get(THIS_MODULE);
 367
 368         fw_priv = class_get_devdata(class_dev);
 369
 370         fw_priv->fw = fw;
 371         retval = sysfs_create_bin_file(&class_dev->kobj, &fw_priv->attr_data);
 372         if (retval) {
 373                 printk(KERN_ERR "%s: sysfs_create_bin_file failed\n",
 374                        __FUNCTION__);
 375                 goto error_unreg;
 376         }
 377
 378         retval = class_device_create_file(class_dev,
 379                                           &class_device_attr_loading);
 380         if (retval) {
 381                 printk(KERN_ERR "%s: class_device_create_file failed\n",
 382                        __FUNCTION__);
 383                 goto error_unreg;
 384         }
 385
 386         if (uevent)
 387                 set_bit(FW_STATUS_READY, &fw_priv->status);
 388         else
 389                 set_bit(FW_STATUS_READY_NOHOTPLUG, &fw_priv->status);
 390         *class_dev_p = class_dev;
 391         goto out;
 392
 393 error_unreg:
 394         class_device_unregister(class_dev);
 395 out:
 396         return retval;
 397 }
 398
 399 static int
 400 _request_firmware(const struct firmware **firmware_p, const char *name,
 401                  struct device *device, int uevent)
 402 {
 403         struct class_device *class_dev;
 404         struct firmware_priv *fw_priv;
 405         struct firmware *firmware;
 406         int retval;
 407
 408         if (!firmware_p)
 409                 return -EINVAL;
 410
 411         *firmware_p = firmware = kzalloc(sizeof(*firmware), GFP_KERNEL);
 412         if (!firmware) {
 413                 printk(KERN_ERR "%s: kmalloc(struct firmware) failed\n",
 414                        __FUNCTION__);
 415                 retval = -ENOMEM;
 416                 goto out;
 417         }
 418
 419         retval = fw_setup_class_device(firmware, &class_dev, name, device,
 420                                        uevent);
 421         if (retval)
 422                 goto error_kfree_fw;
 423
 424         fw_priv = class_get_devdata(class_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(&class_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         class_device_unregister(class_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         if (fw) {
 488                 vfree(fw->data);
 489                 kfree(fw);
 490         }
 491 }
 492
 493 /* Async support */
 494 struct firmware_work {
 495         struct work_struct work;
 496         struct module *module;
 497         const char *name;
 498         struct device *device;
 499         void *context;
 500         void (*cont)(const struct firmware *fw, void *context);
 501         int uevent;
 502 };
 503
 504 static int
 505 request_firmware_work_func(void *arg)
 506 {
 507         struct firmware_work *fw_work = arg;
 508         const struct firmware *fw;
 509         int ret;
 510         if (!arg) {
 511                 WARN_ON(1);
 512                 return 0;
 513         }
 514         daemonize("%s/%s", "firmware", fw_work->name);
 515         ret = _request_firmware(&fw, fw_work->name, fw_work->device,
 516                 fw_work->uevent);
 517         if (ret < 0)
 518                 fw_work->cont(NULL, fw_work->context);
 519         else {
 520                 fw_work->cont(fw, fw_work->context);
 521                 release_firmware(fw);
 522         }
 523         module_put(fw_work->module);
 524         kfree(fw_work);
 525         return ret;
 526 }
 527
 528 /**
 529  * request_firmware_nowait: asynchronous version of request_firmware
 530  * @module: module requesting the firmware
 531  * @uevent: sends uevent to copy the firmware image if this flag
 532  *      is non-zero else the firmware copy must be done manually.
 533  * @name: name of firmware file
 534  * @device: device for which firmware is being loaded
 535  * @context: will be passed over to @cont, and
 536  *      @fw may be %NULL if firmware request fails.
 537  * @cont: function will be called asynchronously when the firmware
 538  *      request is over.
 539  *
 540  *      Asynchronous variant of request_firmware() for contexts where
 541  *      it is not possible to sleep.
 542  **/
 543 int
 544 request_firmware_nowait(
 545         struct module *module, int uevent,
 546         const char *name, struct device *device, void *context,
 547         void (*cont)(const struct firmware *fw, void *context))
 548 {
 549         struct firmware_work *fw_work = kmalloc(sizeof (struct firmware_work),
 550                                                 GFP_ATOMIC);
 551         int ret;
 552
 553         if (!fw_work)
 554                 return -ENOMEM;
 555         if (!try_module_get(module)) {
 556                 kfree(fw_work);
 557                 return -EFAULT;
 558         }
 559
 560         *fw_work = (struct firmware_work) {
 561                 .module = module,
 562                 .name = name,
 563                 .device = device,
 564                 .context = context,
 565                 .cont = cont,
 566                 .uevent = uevent,
 567         };
 568
 569         ret = kernel_thread(request_firmware_work_func, fw_work,
 570                             CLONE_FS | CLONE_FILES);
 571
 572         if (ret < 0) {
 573                 fw_work->cont(NULL, fw_work->context);
 574                 module_put(fw_work->module);
 575                 kfree(fw_work);
 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);