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 #define to_dev(obj) container_of(obj, struct device, kobj)
  25
  26 MODULE_AUTHOR("Manuel Estrada Sainz <ranty@debian.org>");
  27 MODULE_DESCRIPTION("Multi purpose firmware loading support");
  28 MODULE_LICENSE("GPL");
  29
  30 enum {
  31         FW_STATUS_LOADING,
  32         FW_STATUS_DONE,
  33         FW_STATUS_ABORT,
  34         FW_STATUS_READY,
  35         FW_STATUS_READY_NOHOTPLUG,
  36 };
  37
  38 static int loading_timeout = 10;        /* In seconds */
  39
  40 /* fw_lock could be moved to 'struct firmware_priv' but since it is just
  41  * guarding for corner cases a global lock should be OK */
  42 static DEFINE_MUTEX(fw_lock);
  43
  44 struct firmware_priv {
  45         char fw_id[FIRMWARE_NAME_MAX];
  46         struct completion completion;
  47         struct bin_attribute attr_data;
  48         struct firmware *fw;
  49         unsigned long status;
  50         int alloc_size;
  51         struct timer_list timeout;
  52 };
  53
  54 static void
  55 fw_load_abort(struct firmware_priv *fw_priv)
  56 {
  57         set_bit(FW_STATUS_ABORT, &fw_priv->status);
  58         wmb();
  59         complete(&fw_priv->completion);
  60 }
  61
  62 static ssize_t
  63 firmware_timeout_show(struct class *class, char *buf)
  64 {
  65         return sprintf(buf, "%d\n", loading_timeout);
  66 }
  67
  68 /**
  69  * firmware_timeout_store - set number of seconds to wait for firmware
  70  * @class: device class pointer
  71  * @buf: buffer to scan for timeout value
  72  * @count: number of bytes in @buf
  73  *
  74  *      Sets the number of seconds to wait for the firmware.  Once
  75  *      this expires an error will be returned to the driver and no
  76  *      firmware will be provided.
  77  *
  78  *      Note: zero means 'wait forever'.
  79  **/
  80 static ssize_t
  81 firmware_timeout_store(struct class *class, const char *buf, size_t count)
  82 {
  83         loading_timeout = simple_strtol(buf, NULL, 10);
  84         if (loading_timeout < 0)
  85                 loading_timeout = 0;
  86         return count;
  87 }
  88
  89 static CLASS_ATTR(timeout, 0644, firmware_timeout_show, firmware_timeout_store);
  90
  91 static void fw_dev_release(struct device *dev);
  92
  93 static int firmware_uevent(struct device *dev, char **envp, int num_envp,
  94                            char *buffer, int buffer_size)
  95 {
  96         struct firmware_priv *fw_priv = dev_get_drvdata(dev);
  97         int i = 0, len = 0;
  98
  99         if (!test_bit(FW_STATUS_READY, &fw_priv->status))
 100                 return -ENODEV;
 101
 102         if (add_uevent_var(envp, num_envp, &i, buffer, buffer_size, &len,
 103                            "FIRMWARE=%s", fw_priv->fw_id))
 104                 return -ENOMEM;
 105         if (add_uevent_var(envp, num_envp, &i, buffer, buffer_size, &len,
 106                            "TIMEOUT=%i", loading_timeout))
 107                 return -ENOMEM;
 108         envp[i] = NULL;
 109
 110         return 0;
 111 }
 112
 113 static struct class firmware_class = {
 114         .name           = "firmware",
 115         .dev_uevent     = firmware_uevent,
 116         .dev_release    = fw_dev_release,
 117 };
 118
 119 static ssize_t firmware_loading_show(struct device *dev,
 120                                      struct device_attribute *attr, char *buf)
 121 {
 122         struct firmware_priv *fw_priv = dev_get_drvdata(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  * @dev: device pointer
 130  * @attr: device attribute pointer
 131  * @buf: buffer to scan for loading control value
 132  * @count: number of bytes in @buf
 133  *
 134  *      The relevant values are:
 135  *
 136  *       1: Start a load, discarding any previous partial load.
 137  *       0: Conclude the load and hand the data to the driver code.
 138  *      -1: Conclude the load with an error and discard any written data.
 139  **/
 140 static ssize_t firmware_loading_store(struct device *dev,
 141                                       struct device_attribute *attr,
 142                                       const char *buf, size_t count)
 143 {
 144         struct firmware_priv *fw_priv = dev_get_drvdata(dev);
 145         int loading = simple_strtol(buf, NULL, 10);
 146
 147         switch (loading) {
 148         case 1:
 149                 mutex_lock(&fw_lock);
 150                 if (!fw_priv->fw) {
 151                         mutex_unlock(&fw_lock);
 152                         break;
 153                 }
 154                 vfree(fw_priv->fw->data);
 155                 fw_priv->fw->data = NULL;
 156                 fw_priv->fw->size = 0;
 157                 fw_priv->alloc_size = 0;
 158                 set_bit(FW_STATUS_LOADING, &fw_priv->status);
 159                 mutex_unlock(&fw_lock);
 160                 break;
 161         case 0:
 162                 if (test_bit(FW_STATUS_LOADING, &fw_priv->status)) {
 163                         complete(&fw_priv->completion);
 164                         clear_bit(FW_STATUS_LOADING, &fw_priv->status);
 165                         break;
 166                 }
 167                 /* fallthrough */
 168         default:
 169                 printk(KERN_ERR "%s: unexpected value (%d)\n", __FUNCTION__,
 170                        loading);
 171                 /* fallthrough */
 172         case -1:
 173                 fw_load_abort(fw_priv);
 174                 break;
 175         }
 176
 177         return count;
 178 }
 179
 180 static DEVICE_ATTR(loading, 0644, 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 device *dev = to_dev(kobj);
 187         struct firmware_priv *fw_priv = dev_get_drvdata(dev);
 188         struct firmware *fw;
 189         ssize_t ret_count = count;
 190
 191         mutex_lock(&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         mutex_unlock(&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 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 device *dev = to_dev(kobj);
 252         struct firmware_priv *fw_priv = dev_get_drvdata(dev);
 253         struct firmware *fw;
 254         ssize_t retval;
 255
 256         if (!capable(CAP_SYS_RAWIO))
 257                 return -EPERM;
 258
 259         mutex_lock(&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         mutex_unlock(&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 fw_dev_release(struct device *dev)
 286 {
 287         struct firmware_priv *fw_priv = dev_get_drvdata(dev);
 288
 289         kfree(fw_priv);
 290         kfree(dev);
 291
 292         module_put(THIS_MODULE);
 293 }
 294
 295 static void
 296 firmware_class_timeout(u_long data)
 297 {
 298         struct firmware_priv *fw_priv = (struct firmware_priv *) data;
 299         fw_load_abort(fw_priv);
 300 }
 301
 302 static inline void fw_setup_device_id(struct device *f_dev, struct device *dev)
 303 {
 304         /* XXX warning we should watch out for name collisions */
 305         strlcpy(f_dev->bus_id, dev->bus_id, BUS_ID_SIZE);
 306 }
 307
 308 static int fw_register_device(struct device **dev_p, const char *fw_name,
 309                               struct device *device)
 310 {
 311         int retval;
 312         struct firmware_priv *fw_priv = kzalloc(sizeof(*fw_priv),
 313                                                 GFP_KERNEL);
 314         struct device *f_dev = kzalloc(sizeof(*f_dev), GFP_KERNEL);
 315
 316         *dev_p = NULL;
 317
 318         if (!fw_priv || !f_dev) {
 319                 printk(KERN_ERR "%s: kmalloc failed\n", __FUNCTION__);
 320                 retval = -ENOMEM;
 321                 goto error_kfree;
 322         }
 323
 324         init_completion(&fw_priv->completion);
 325         fw_priv->attr_data = firmware_attr_data_tmpl;
 326         strlcpy(fw_priv->fw_id, fw_name, FIRMWARE_NAME_MAX);
 327
 328         fw_priv->timeout.function = firmware_class_timeout;
 329         fw_priv->timeout.data = (u_long) fw_priv;
 330         init_timer(&fw_priv->timeout);
 331
 332         fw_setup_device_id(f_dev, device);
 333         f_dev->parent = device;
 334         f_dev->class = &firmware_class;
 335         dev_set_drvdata(f_dev, fw_priv);
 336         retval = device_register(f_dev);
 337         if (retval) {
 338                 printk(KERN_ERR "%s: device_register failed\n",
 339                        __FUNCTION__);
 340                 goto error_kfree;
 341         }
 342         *dev_p = f_dev;
 343         return 0;
 344
 345 error_kfree:
 346         kfree(fw_priv);
 347         kfree(f_dev);
 348         return retval;
 349 }
 350
 351 static int fw_setup_device(struct firmware *fw, struct device **dev_p,
 352                            const char *fw_name, struct device *device,
 353                            int uevent)
 354 {
 355         struct device *f_dev;
 356         struct firmware_priv *fw_priv;
 357         int retval;
 358
 359         *dev_p = NULL;
 360         retval = fw_register_device(&f_dev, fw_name, device);
 361         if (retval)
 362                 goto out;
 363
 364         /* Need to pin this module until class device is destroyed */
 365         __module_get(THIS_MODULE);
 366
 367         fw_priv = dev_get_drvdata(f_dev);
 368
 369         fw_priv->fw = fw;
 370         retval = sysfs_create_bin_file(&f_dev->kobj, &fw_priv->attr_data);
 371         if (retval) {
 372                 printk(KERN_ERR "%s: sysfs_create_bin_file failed\n",
 373                        __FUNCTION__);
 374                 goto error_unreg;
 375         }
 376
 377         retval = device_create_file(f_dev, &dev_attr_loading);
 378         if (retval) {
 379                 printk(KERN_ERR "%s: device_create_file failed\n",
 380                        __FUNCTION__);
 381                 goto error_unreg;
 382         }
 383
 384         if (uevent)
 385                 set_bit(FW_STATUS_READY, &fw_priv->status);
 386         else
 387                 set_bit(FW_STATUS_READY_NOHOTPLUG, &fw_priv->status);
 388         *dev_p = f_dev;
 389         goto out;
 390
 391 error_unreg:
 392         device_unregister(f_dev);
 393 out:
 394         return retval;
 395 }
 396
 397 static int
 398 _request_firmware(const struct firmware **firmware_p, const char *name,
 399                  struct device *device, int uevent)
 400 {
 401         struct device *f_dev;
 402         struct firmware_priv *fw_priv;
 403         struct firmware *firmware;
 404         int retval;
 405
 406         if (!firmware_p)
 407                 return -EINVAL;
 408
 409         *firmware_p = firmware = kzalloc(sizeof(*firmware), GFP_KERNEL);
 410         if (!firmware) {
 411                 printk(KERN_ERR "%s: kmalloc(struct firmware) failed\n",
 412                        __FUNCTION__);
 413                 retval = -ENOMEM;
 414                 goto out;
 415         }
 416
 417         retval = fw_setup_device(firmware, &f_dev, name, device, uevent);
 418         if (retval)
 419                 goto error_kfree_fw;
 420
 421         fw_priv = dev_get_drvdata(f_dev);
 422
 423         if (uevent) {
 424                 if (loading_timeout > 0) {
 425                         fw_priv->timeout.expires = jiffies + loading_timeout * HZ;
 426                         add_timer(&fw_priv->timeout);
 427                 }
 428
 429                 kobject_uevent(&f_dev->kobj, KOBJ_ADD);
 430                 wait_for_completion(&fw_priv->completion);
 431                 set_bit(FW_STATUS_DONE, &fw_priv->status);
 432                 del_timer_sync(&fw_priv->timeout);
 433         } else
 434                 wait_for_completion(&fw_priv->completion);
 435
 436         mutex_lock(&fw_lock);
 437         if (!fw_priv->fw->size || test_bit(FW_STATUS_ABORT, &fw_priv->status)) {
 438                 retval = -ENOENT;
 439                 release_firmware(fw_priv->fw);
 440                 *firmware_p = NULL;
 441         }
 442         fw_priv->fw = NULL;
 443         mutex_unlock(&fw_lock);
 444         device_unregister(f_dev);
 445         goto out;
 446
 447 error_kfree_fw:
 448         kfree(firmware);
 449         *firmware_p = NULL;
 450 out:
 451         return retval;
 452 }
 453
 454 /**
 455  * request_firmware: - send firmware request and wait for it
 456  * @firmware_p: pointer to firmware image
 457  * @name: name of firmware file
 458  * @device: device for which firmware is being loaded
 459  *
 460  *      @firmware_p will be used to return a firmware image by the name
 461  *      of @name for device @device.
 462  *
 463  *      Should be called from user context where sleeping is allowed.
 464  *
 465  *      @name will be used as $FIRMWARE in the uevent environment and
 466  *      should be distinctive enough not to be confused with any other
 467  *      firmware image for this or any other device.
 468  **/
 469 int
 470 request_firmware(const struct firmware **firmware_p, const char *name,
 471                  struct device *device)
 472 {
 473         int uevent = 1;
 474         return _request_firmware(firmware_p, name, device, uevent);
 475 }
 476
 477 /**
 478  * release_firmware: - release the resource associated with a firmware image
 479  * @fw: firmware resource to release
 480  **/
 481 void
 482 release_firmware(const struct firmware *fw)
 483 {
 484         if (fw) {
 485                 vfree(fw->data);
 486                 kfree(fw);
 487         }
 488 }
 489
 490 /* Async support */
 491 struct firmware_work {
 492         struct work_struct work;
 493         struct module *module;
 494         const char *name;
 495         struct device *device;
 496         void *context;
 497         void (*cont)(const struct firmware *fw, void *context);
 498         int uevent;
 499 };
 500
 501 static int
 502 request_firmware_work_func(void *arg)
 503 {
 504         struct firmware_work *fw_work = arg;
 505         const struct firmware *fw;
 506         int ret;
 507         if (!arg) {
 508                 WARN_ON(1);
 509                 return 0;
 510         }
 511         ret = _request_firmware(&fw, fw_work->name, fw_work->device,
 512                 fw_work->uevent);
 513         if (ret < 0)
 514                 fw_work->cont(NULL, fw_work->context);
 515         else {
 516                 fw_work->cont(fw, fw_work->context);
 517                 release_firmware(fw);
 518         }
 519         module_put(fw_work->module);
 520         kfree(fw_work);
 521         return ret;
 522 }
 523
 524 /**
 525  * request_firmware_nowait: asynchronous version of request_firmware
 526  * @module: module requesting the firmware
 527  * @uevent: sends uevent to copy the firmware image if this flag
 528  *      is non-zero else the firmware copy must be done manually.
 529  * @name: name of firmware file
 530  * @device: device for which firmware is being loaded
 531  * @context: will be passed over to @cont, and
 532  *      @fw may be %NULL if firmware request fails.
 533  * @cont: function will be called asynchronously when the firmware
 534  *      request is over.
 535  *
 536  *      Asynchronous variant of request_firmware() for contexts where
 537  *      it is not possible to sleep.
 538  **/
 539 int
 540 request_firmware_nowait(
 541         struct module *module, int uevent,
 542         const char *name, struct device *device, void *context,
 543         void (*cont)(const struct firmware *fw, void *context))
 544 {
 545         struct task_struct *task;
 546         struct firmware_work *fw_work = kmalloc(sizeof (struct firmware_work),
 547                                                 GFP_ATOMIC);
 548
 549         if (!fw_work)
 550                 return -ENOMEM;
 551         if (!try_module_get(module)) {
 552                 kfree(fw_work);
 553                 return -EFAULT;
 554         }
 555
 556         *fw_work = (struct firmware_work) {
 557                 .module = module,
 558                 .name = name,
 559                 .device = device,
 560                 .context = context,
 561                 .cont = cont,
 562                 .uevent = uevent,
 563         };
 564
 565         task = kthread_run(request_firmware_work_func, fw_work,
 566                             "firmware/%s", name);
 567
 568         if (IS_ERR(task)) {
 569                 fw_work->cont(NULL, fw_work->context);
 570                 module_put(fw_work->module);
 571                 kfree(fw_work);
 572                 return PTR_ERR(task);
 573         }
 574         return 0;
 575 }
 576
 577 static int __init
 578 firmware_class_init(void)
 579 {
 580         int error;
 581         error = class_register(&firmware_class);
 582         if (error) {
 583                 printk(KERN_ERR "%s: class_register failed\n", __FUNCTION__);
 584                 return error;
 585         }
 586         error = class_create_file(&firmware_class, &class_attr_timeout);
 587         if (error) {
 588                 printk(KERN_ERR "%s: class_create_file failed\n",
 589                        __FUNCTION__);
 590                 class_unregister(&firmware_class);
 591         }
 592         return error;
 593
 594 }
 595 static void __exit
 596 firmware_class_exit(void)
 597 {
 598         class_unregister(&firmware_class);
 599 }
 600
 601 fs_initcall(firmware_class_init);
 602 module_exit(firmware_class_exit);
 603
 604 EXPORT_SYMBOL(release_firmware);
 605 EXPORT_SYMBOL(request_firmware);
 606 EXPORT_SYMBOL(request_firmware_nowait);