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 #include <linux/kthread.h>
  20
  21 #include <linux/firmware.h>
  22 #include "base.h"
  23
  24 MODULE_AUTHOR("Manuel Estrada Sainz <ranty@debian.org>");
  25 MODULE_DESCRIPTION("Multi purpose firmware loading support");
  26 MODULE_LICENSE("GPL");
  27
  28 enum {
  29         FW_STATUS_LOADING,
  30         FW_STATUS_DONE,
  31         FW_STATUS_ABORT,
  32         FW_STATUS_READY,
  33         FW_STATUS_READY_NOHOTPLUG,
  34 };
  35
  36 static int loading_timeout = 10;        /* 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 static void
  53 fw_load_abort(struct firmware_priv *fw_priv)
  54 {
  55         set_bit(FW_STATUS_ABORT, &fw_priv->status);
  56         wmb();
  57         complete(&fw_priv->completion);
  58 }
  59
  60 static ssize_t
  61 firmware_timeout_show(struct class *class, char *buf)
  62 {
  63         return sprintf(buf, "%d\n", loading_timeout);
  64 }
  65
  66 /**
  67  * firmware_timeout_store - set number of seconds to wait for firmware
  68  * @class: device class pointer
  69  * @buf: buffer to scan for timeout value
  70  * @count: number of bytes in @buf
  71  *
  72  *      Sets the number of seconds to wait for the firmware.  Once
  73  *      this expires an error will be returned to the driver and no
  74  *      firmware will be provided.
  75  *
  76  *      Note: zero means 'wait forever'.
  77  **/
  78 static ssize_t
  79 firmware_timeout_store(struct class *class, const char *buf, size_t count)
  80 {
  81         loading_timeout = simple_strtol(buf, NULL, 10);
  82         if (loading_timeout < 0)
  83                 loading_timeout = 0;
  84         return count;
  85 }
  86
  87 static CLASS_ATTR(timeout, 0644, firmware_timeout_show, firmware_timeout_store);
  88
  89 static void  fw_class_dev_release(struct class_device *class_dev);
  90
  91 static int firmware_class_uevent(struct class_device *class_dev, char **envp,
  92                                  int num_envp, char *buffer, int buffer_size)
  93 {
  94         struct firmware_priv *fw_priv = class_get_devdata(class_dev);
  95         int i = 0, len = 0;
  96
  97         if (!test_bit(FW_STATUS_READY, &fw_priv->status))
  98                 return -ENODEV;
  99
 100         if (add_uevent_var(envp, num_envp, &i, buffer, buffer_size, &len,
 101                            "FIRMWARE=%s", fw_priv->fw_id))
 102                 return -ENOMEM;
 103         if (add_uevent_var(envp, num_envp, &i, buffer, buffer_size, &len,
 104                            "TIMEOUT=%i", loading_timeout))
 105                 return -ENOMEM;
 106         envp[i] = NULL;
 107
 108         return 0;
 109 }
 110
 111 static struct class firmware_class = {
 112         .name           = "firmware",
 113         .uevent         = firmware_class_uevent,
 114         .release        = fw_class_dev_release,
 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 - set value in the 'loading' control file
 127  * @class_dev: class_device pointer
 128  * @buf: buffer to scan for loading control value
 129  * @count: number of bytes in @buf
 130  *
 131  *      The relevant values are:
 132  *
 133  *       1: Start a load, discarding any previous partial load.
 134  *       0: Conclude the load and hand the data to the driver code.
 135  *      -1: Conclude the load with an error and discard any written data.
 136  **/
 137 static ssize_t
 138 firmware_loading_store(struct class_device *class_dev,
 139                        const char *buf, size_t count)
 140 {
 141         struct firmware_priv *fw_priv = class_get_devdata(class_dev);
 142         int loading = simple_strtol(buf, NULL, 10);
 143
 144         switch (loading) {
 145         case 1:
 146                 mutex_lock(&fw_lock);
 147                 if (!fw_priv->fw) {
 148                         mutex_unlock(&fw_lock);
 149                         break;
 150                 }
 151                 vfree(fw_priv->fw->data);
 152                 fw_priv->fw->data = NULL;
 153                 fw_priv->fw->size = 0;
 154                 fw_priv->alloc_size = 0;
 155                 set_bit(FW_STATUS_LOADING, &fw_priv->status);
 156                 mutex_unlock(&fw_lock);
 157                 break;
 158         case 0:
 159                 if (test_bit(FW_STATUS_LOADING, &fw_priv->status)) {
 160                         complete(&fw_priv->completion);
 161                         clear_bit(FW_STATUS_LOADING, &fw_priv->status);
 162                         break;
 163                 }
 164                 /* fallthrough */
 165         default:
 166                 printk(KERN_ERR "%s: unexpected value (%d)\n", __FUNCTION__,
 167                        loading);
 168                 /* fallthrough */
 169         case -1:
 170                 fw_load_abort(fw_priv);
 171                 break;
 172         }
 173
 174         return count;
 175 }
 176
 177 static CLASS_DEVICE_ATTR(loading, 0644,
 178                         firmware_loading_show, firmware_loading_store);
 179
 180 static ssize_t
 181 firmware_data_read(struct kobject *kobj,
 182                    char *buffer, loff_t offset, size_t count)
 183 {
 184         struct class_device *class_dev = to_class_dev(kobj);
 185         struct firmware_priv *fw_priv = class_get_devdata(class_dev);
 186         struct firmware *fw;
 187         ssize_t ret_count = 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         if (offset > fw->size) {
 196                 ret_count = 0;
 197                 goto out;
 198         }
 199         if (offset + ret_count > fw->size)
 200                 ret_count = fw->size - offset;
 201
 202         memcpy(buffer, fw->data + offset, ret_count);
 203 out:
 204         mutex_unlock(&fw_lock);
 205         return ret_count;
 206 }
 207
 208 static int
 209 fw_realloc_buffer(struct firmware_priv *fw_priv, int min_size)
 210 {
 211         u8 *new_data;
 212         int new_size = fw_priv->alloc_size;
 213
 214         if (min_size <= fw_priv->alloc_size)
 215                 return 0;
 216
 217         new_size = ALIGN(min_size, PAGE_SIZE);
 218         new_data = vmalloc(new_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 = new_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         mutex_lock(&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         mutex_unlock(&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 uevent)
 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 (uevent)
 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 uevent)
 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                                        uevent);
 422         if (retval)
 423                 goto error_kfree_fw;
 424
 425         fw_priv = class_get_devdata(class_dev);
 426
 427         if (uevent) {
 428                 if (loading_timeout > 0) {
 429                         fw_priv->timeout.expires = jiffies + loading_timeout * HZ;
 430                         add_timer(&fw_priv->timeout);
 431                 }
 432
 433                 kobject_uevent(&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         mutex_lock(&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         mutex_unlock(&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: - send firmware request 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 uevent 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 uevent = 1;
 478         return _request_firmware(firmware_p, name, device, uevent);
 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 /* Async support */
 495 struct firmware_work {
 496         struct work_struct work;
 497         struct module *module;
 498         const char *name;
 499         struct device *device;
 500         void *context;
 501         void (*cont)(const struct firmware *fw, void *context);
 502         int uevent;
 503 };
 504
 505 static int
 506 request_firmware_work_func(void *arg)
 507 {
 508         struct firmware_work *fw_work = arg;
 509         const struct firmware *fw;
 510         int ret;
 511         if (!arg) {
 512                 WARN_ON(1);
 513                 return 0;
 514         }
 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 task_struct *task;
 550         struct firmware_work *fw_work = kmalloc(sizeof (struct firmware_work),
 551                                                 GFP_ATOMIC);
 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         task = kthread_run(request_firmware_work_func, fw_work,
 570                             "firmware/%s", name);
 571
 572         if (IS_ERR(task)) {
 573                 fw_work->cont(NULL, fw_work->context);
 574                 module_put(fw_work->module);
 575                 kfree(fw_work);
 576                 return PTR_ERR(task);
 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 fs_initcall(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);