drivers/base/firmware_class.c

   1 /*
   2  * firmware_class.c - Multi purpose firmware loading support
   3  *
   4  * Copyright (c) 2003 Manuel Estrada Sainz
   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");
  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 };
  35
  36 static int loading_timeout = 60;        /* 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_dev_release(struct device *dev);
  90
  91 static int firmware_uevent(struct device *dev, struct kobj_uevent_env *env)
  92 {
  93         struct firmware_priv *fw_priv = dev_get_drvdata(dev);
  94
  95         if (add_uevent_var(env, "FIRMWARE=%s", fw_priv->fw_id))
  96                 return -ENOMEM;
  97         if (add_uevent_var(env, "TIMEOUT=%i", loading_timeout))
  98                 return -ENOMEM;
  99
 100         return 0;
 101 }
 102
 103 static struct class firmware_class = {
 104         .name           = "firmware",
 105         .dev_uevent     = firmware_uevent,
 106         .dev_release    = fw_dev_release,
 107 };
 108
 109 static ssize_t firmware_loading_show(struct device *dev,
 110                                      struct device_attribute *attr, char *buf)
 111 {
 112         struct firmware_priv *fw_priv = dev_get_drvdata(dev);
 113         int loading = test_bit(FW_STATUS_LOADING, &fw_priv->status);
 114         return sprintf(buf, "%d\n", loading);
 115 }
 116
 117 /**
 118  * firmware_loading_store - set value in the 'loading' control file
 119  * @dev: device pointer
 120  * @attr: device attribute pointer
 121  * @buf: buffer to scan for loading control value
 122  * @count: number of bytes in @buf
 123  *
 124  *      The relevant values are:
 125  *
 126  *       1: Start a load, discarding any previous partial load.
 127  *       0: Conclude the load and hand the data to the driver code.
 128  *      -1: Conclude the load with an error and discard any written data.
 129  **/
 130 static ssize_t firmware_loading_store(struct device *dev,
 131                                       struct device_attribute *attr,
 132                                       const char *buf, size_t count)
 133 {
 134         struct firmware_priv *fw_priv = dev_get_drvdata(dev);
 135         int loading = simple_strtol(buf, NULL, 10);
 136
 137         switch (loading) {
 138         case 1:
 139                 mutex_lock(&fw_lock);
 140                 if (!fw_priv->fw) {
 141                         mutex_unlock(&fw_lock);
 142                         break;
 143                 }
 144                 vfree(fw_priv->fw->data);
 145                 fw_priv->fw->data = NULL;
 146                 fw_priv->fw->size = 0;
 147                 fw_priv->alloc_size = 0;
 148                 set_bit(FW_STATUS_LOADING, &fw_priv->status);
 149                 mutex_unlock(&fw_lock);
 150                 break;
 151         case 0:
 152                 if (test_bit(FW_STATUS_LOADING, &fw_priv->status)) {
 153                         complete(&fw_priv->completion);
 154                         clear_bit(FW_STATUS_LOADING, &fw_priv->status);
 155                         break;
 156                 }
 157                 /* fallthrough */
 158         default:
 159                 printk(KERN_ERR "%s: unexpected value (%d)\n", __func__,
 160                        loading);
 161                 /* fallthrough */
 162         case -1:
 163                 fw_load_abort(fw_priv);
 164                 break;
 165         }
 166
 167         return count;
 168 }
 169
 170 static DEVICE_ATTR(loading, 0644, firmware_loading_show, firmware_loading_store);
 171
 172 static ssize_t
 173 firmware_data_read(struct kobject *kobj, struct bin_attribute *bin_attr,
 174                    char *buffer, loff_t offset, size_t count)
 175 {
 176         struct device *dev = to_dev(kobj);
 177         struct firmware_priv *fw_priv = dev_get_drvdata(dev);
 178         struct firmware *fw;
 179         ssize_t ret_count = count;
 180
 181         mutex_lock(&fw_lock);
 182         fw = fw_priv->fw;
 183         if (!fw || test_bit(FW_STATUS_DONE, &fw_priv->status)) {
 184                 ret_count = -ENODEV;
 185                 goto out;
 186         }
 187         if (offset > fw->size) {
 188                 ret_count = 0;
 189                 goto out;
 190         }
 191         if (offset + ret_count > fw->size)
 192                 ret_count = fw->size - offset;
 193
 194         memcpy(buffer, fw->data + offset, ret_count);
 195 out:
 196         mutex_unlock(&fw_lock);
 197         return ret_count;
 198 }
 199
 200 static int
 201 fw_realloc_buffer(struct firmware_priv *fw_priv, int min_size)
 202 {
 203         u8 *new_data;
 204         int new_size = fw_priv->alloc_size;
 205
 206         if (min_size <= fw_priv->alloc_size)
 207                 return 0;
 208
 209         new_size = ALIGN(min_size, PAGE_SIZE);
 210         new_data = vmalloc(new_size);
 211         if (!new_data) {
 212                 printk(KERN_ERR "%s: unable to alloc buffer\n", __func__);
 213                 /* Make sure that we don't keep incomplete data */
 214                 fw_load_abort(fw_priv);
 215                 return -ENOMEM;
 216         }
 217         fw_priv->alloc_size = new_size;
 218         if (fw_priv->fw->data) {
 219                 memcpy(new_data, fw_priv->fw->data, fw_priv->fw->size);
 220                 vfree(fw_priv->fw->data);
 221         }
 222         fw_priv->fw->data = new_data;
 223         BUG_ON(min_size > fw_priv->alloc_size);
 224         return 0;
 225 }
 226
 227 /**
 228  * firmware_data_write - write method for firmware
 229  * @kobj: kobject for the device
 230  * @bin_attr: bin_attr structure
 231  * @buffer: buffer being written
 232  * @offset: buffer offset for write in total data store area
 233  * @count: buffer size
 234  *
 235  *      Data written to the 'data' attribute will be later handed to
 236  *      the driver as a firmware image.
 237  **/
 238 static ssize_t
 239 firmware_data_write(struct kobject *kobj, struct bin_attribute *bin_attr,
 240                     char *buffer, loff_t offset, size_t count)
 241 {
 242         struct device *dev = to_dev(kobj);
 243         struct firmware_priv *fw_priv = dev_get_drvdata(dev);
 244         struct firmware *fw;
 245         ssize_t retval;
 246
 247         if (!capable(CAP_SYS_RAWIO))
 248                 return -EPERM;
 249
 250         mutex_lock(&fw_lock);
 251         fw = fw_priv->fw;
 252         if (!fw || test_bit(FW_STATUS_DONE, &fw_priv->status)) {
 253                 retval = -ENODEV;
 254                 goto out;
 255         }
 256         retval = fw_realloc_buffer(fw_priv, offset + count);
 257         if (retval)
 258                 goto out;
 259
 260         memcpy(fw->data + offset, buffer, count);
 261
 262         fw->size = max_t(size_t, offset + count, fw->size);
 263         retval = count;
 264 out:
 265         mutex_unlock(&fw_lock);
 266         return retval;
 267 }
 268
 269 static struct bin_attribute firmware_attr_data_tmpl = {
 270         .attr = {.name = "data", .mode = 0644},
 271         .size = 0,
 272         .read = firmware_data_read,
 273         .write = firmware_data_write,
 274 };
 275
 276 static void fw_dev_release(struct device *dev)
 277 {
 278         struct firmware_priv *fw_priv = dev_get_drvdata(dev);
 279
 280         kfree(fw_priv);
 281         kfree(dev);
 282
 283         module_put(THIS_MODULE);
 284 }
 285
 286 static void
 287 firmware_class_timeout(u_long data)
 288 {
 289         struct firmware_priv *fw_priv = (struct firmware_priv *) data;
 290         fw_load_abort(fw_priv);
 291 }
 292
 293 static inline void fw_setup_device_id(struct device *f_dev, struct device *dev)
 294 {
 295         /* XXX warning we should watch out for name collisions */
 296         strlcpy(f_dev->bus_id, dev->bus_id, BUS_ID_SIZE);
 297 }
 298
 299 static int fw_register_device(struct device **dev_p, const char *fw_name,
 300                               struct device *device)
 301 {
 302         int retval;
 303         struct firmware_priv *fw_priv = kzalloc(sizeof(*fw_priv),
 304                                                 GFP_KERNEL);
 305         struct device *f_dev = kzalloc(sizeof(*f_dev), GFP_KERNEL);
 306
 307         *dev_p = NULL;
 308
 309         if (!fw_priv || !f_dev) {
 310                 printk(KERN_ERR "%s: kmalloc failed\n", __func__);
 311                 retval = -ENOMEM;
 312                 goto error_kfree;
 313         }
 314
 315         init_completion(&fw_priv->completion);
 316         fw_priv->attr_data = firmware_attr_data_tmpl;
 317         strlcpy(fw_priv->fw_id, fw_name, FIRMWARE_NAME_MAX);
 318
 319         fw_priv->timeout.function = firmware_class_timeout;
 320         fw_priv->timeout.data = (u_long) fw_priv;
 321         init_timer(&fw_priv->timeout);
 322
 323         fw_setup_device_id(f_dev, device);
 324         f_dev->parent = device;
 325         f_dev->class = &firmware_class;
 326         dev_set_drvdata(f_dev, fw_priv);
 327         f_dev->uevent_suppress = 1;
 328         retval = device_register(f_dev);
 329         if (retval) {
 330                 printk(KERN_ERR "%s: device_register failed\n",
 331                        __func__);
 332                 goto error_kfree;
 333         }
 334         *dev_p = f_dev;
 335         return 0;
 336
 337 error_kfree:
 338         kfree(fw_priv);
 339         kfree(f_dev);
 340         return retval;
 341 }
 342
 343 static int fw_setup_device(struct firmware *fw, struct device **dev_p,
 344                            const char *fw_name, struct device *device,
 345                            int uevent)
 346 {
 347         struct device *f_dev;
 348         struct firmware_priv *fw_priv;
 349         int retval;
 350
 351         *dev_p = NULL;
 352         retval = fw_register_device(&f_dev, fw_name, device);
 353         if (retval)
 354                 goto out;
 355
 356         /* Need to pin this module until class device is destroyed */
 357         __module_get(THIS_MODULE);
 358
 359         fw_priv = dev_get_drvdata(f_dev);
 360
 361         fw_priv->fw = fw;
 362         retval = sysfs_create_bin_file(&f_dev->kobj, &fw_priv->attr_data);
 363         if (retval) {
 364                 printk(KERN_ERR "%s: sysfs_create_bin_file failed\n",
 365                        __func__);
 366                 goto error_unreg;
 367         }
 368
 369         retval = device_create_file(f_dev, &dev_attr_loading);
 370         if (retval) {
 371                 printk(KERN_ERR "%s: device_create_file failed\n",
 372                        __func__);
 373                 goto error_unreg;
 374         }
 375
 376         if (uevent)
 377                 f_dev->uevent_suppress = 0;
 378         *dev_p = f_dev;
 379         goto out;
 380
 381 error_unreg:
 382         device_unregister(f_dev);
 383 out:
 384         return retval;
 385 }
 386
 387 static int
 388 _request_firmware(const struct firmware **firmware_p, const char *name,
 389                  struct device *device, int uevent)
 390 {
 391         struct device *f_dev;
 392         struct firmware_priv *fw_priv;
 393         struct firmware *firmware;
 394         int retval;
 395
 396         if (!firmware_p)
 397                 return -EINVAL;
 398
 399         *firmware_p = firmware = kzalloc(sizeof(*firmware), GFP_KERNEL);
 400         if (!firmware) {
 401                 printk(KERN_ERR "%s: kmalloc(struct firmware) failed\n",
 402                        __func__);
 403                 retval = -ENOMEM;
 404                 goto out;
 405         }
 406
 407         retval = fw_setup_device(firmware, &f_dev, name, device, uevent);
 408         if (retval)
 409                 goto error_kfree_fw;
 410
 411         fw_priv = dev_get_drvdata(f_dev);
 412
 413         if (uevent) {
 414                 if (loading_timeout > 0) {
 415                         fw_priv->timeout.expires = jiffies + loading_timeout * HZ;
 416                         add_timer(&fw_priv->timeout);
 417                 }
 418
 419                 kobject_uevent(&f_dev->kobj, KOBJ_ADD);
 420                 wait_for_completion(&fw_priv->completion);
 421                 set_bit(FW_STATUS_DONE, &fw_priv->status);
 422                 del_timer_sync(&fw_priv->timeout);
 423         } else
 424                 wait_for_completion(&fw_priv->completion);
 425
 426         mutex_lock(&fw_lock);
 427         if (!fw_priv->fw->size || test_bit(FW_STATUS_ABORT, &fw_priv->status)) {
 428                 retval = -ENOENT;
 429                 release_firmware(fw_priv->fw);
 430                 *firmware_p = NULL;
 431         }
 432         fw_priv->fw = NULL;
 433         mutex_unlock(&fw_lock);
 434         device_unregister(f_dev);
 435         goto out;
 436
 437 error_kfree_fw:
 438         kfree(firmware);
 439         *firmware_p = NULL;
 440 out:
 441         return retval;
 442 }
 443
 444 /**
 445  * request_firmware: - send firmware request and wait for it
 446  * @firmware_p: pointer to firmware image
 447  * @name: name of firmware file
 448  * @device: device for which firmware is being loaded
 449  *
 450  *      @firmware_p will be used to return a firmware image by the name
 451  *      of @name for device @device.
 452  *
 453  *      Should be called from user context where sleeping is allowed.
 454  *
 455  *      @name will be used as $FIRMWARE in the uevent environment and
 456  *      should be distinctive enough not to be confused with any other
 457  *      firmware image for this or any other device.
 458  **/
 459 int
 460 request_firmware(const struct firmware **firmware_p, const char *name,
 461                  struct device *device)
 462 {
 463         int uevent = 1;
 464         return _request_firmware(firmware_p, name, device, uevent);
 465 }
 466
 467 /**
 468  * release_firmware: - release the resource associated with a firmware image
 469  * @fw: firmware resource to release
 470  **/
 471 void
 472 release_firmware(const struct firmware *fw)
 473 {
 474         if (fw) {
 475                 vfree(fw->data);
 476                 kfree(fw);
 477         }
 478 }
 479
 480 /* Async support */
 481 struct firmware_work {
 482         struct work_struct work;
 483         struct module *module;
 484         const char *name;
 485         struct device *device;
 486         void *context;
 487         void (*cont)(const struct firmware *fw, void *context);
 488         int uevent;
 489 };
 490
 491 static int
 492 request_firmware_work_func(void *arg)
 493 {
 494         struct firmware_work *fw_work = arg;
 495         const struct firmware *fw;
 496         int ret;
 497         if (!arg) {
 498                 WARN_ON(1);
 499                 return 0;
 500         }
 501         ret = _request_firmware(&fw, fw_work->name, fw_work->device,
 502                 fw_work->uevent);
 503         if (ret < 0)
 504                 fw_work->cont(NULL, fw_work->context);
 505         else {
 506                 fw_work->cont(fw, fw_work->context);
 507                 release_firmware(fw);
 508         }
 509         module_put(fw_work->module);
 510         kfree(fw_work);
 511         return ret;
 512 }
 513
 514 /**
 515  * request_firmware_nowait: asynchronous version of request_firmware
 516  * @module: module requesting the firmware
 517  * @uevent: sends uevent to copy the firmware image if this flag
 518  *      is non-zero else the firmware copy must be done manually.
 519  * @name: name of firmware file
 520  * @device: device for which firmware is being loaded
 521  * @context: will be passed over to @cont, and
 522  *      @fw may be %NULL if firmware request fails.
 523  * @cont: function will be called asynchronously when the firmware
 524  *      request is over.
 525  *
 526  *      Asynchronous variant of request_firmware() for contexts where
 527  *      it is not possible to sleep.
 528  **/
 529 int
 530 request_firmware_nowait(
 531         struct module *module, int uevent,
 532         const char *name, struct device *device, void *context,
 533         void (*cont)(const struct firmware *fw, void *context))
 534 {
 535         struct task_struct *task;
 536         struct firmware_work *fw_work = kmalloc(sizeof (struct firmware_work),
 537                                                 GFP_ATOMIC);
 538
 539         if (!fw_work)
 540                 return -ENOMEM;
 541         if (!try_module_get(module)) {
 542                 kfree(fw_work);
 543                 return -EFAULT;
 544         }
 545
 546         *fw_work = (struct firmware_work) {
 547                 .module = module,
 548                 .name = name,
 549                 .device = device,
 550                 .context = context,
 551                 .cont = cont,
 552                 .uevent = uevent,
 553         };
 554
 555         task = kthread_run(request_firmware_work_func, fw_work,
 556                             "firmware/%s", name);
 557
 558         if (IS_ERR(task)) {
 559                 fw_work->cont(NULL, fw_work->context);
 560                 module_put(fw_work->module);
 561                 kfree(fw_work);
 562                 return PTR_ERR(task);
 563         }
 564         return 0;
 565 }
 566
 567 static int __init
 568 firmware_class_init(void)
 569 {
 570         int error;
 571         error = class_register(&firmware_class);
 572         if (error) {
 573                 printk(KERN_ERR "%s: class_register failed\n", __func__);
 574                 return error;
 575         }
 576         error = class_create_file(&firmware_class, &class_attr_timeout);
 577         if (error) {
 578                 printk(KERN_ERR "%s: class_create_file failed\n",
 579                        __func__);
 580                 class_unregister(&firmware_class);
 581         }
 582         return error;
 583
 584 }
 585 static void __exit
 586 firmware_class_exit(void)
 587 {
 588         class_unregister(&firmware_class);
 589 }
 590
 591 fs_initcall(firmware_class_init);
 592 module_exit(firmware_class_exit);
 593
 594 EXPORT_SYMBOL(release_firmware);
 595 EXPORT_SYMBOL(request_firmware);
 596 EXPORT_SYMBOL(request_firmware_nowait);