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/device.h>
  11 #include <linux/module.h>
  12 #include <linux/init.h>
  13 #include <linux/timer.h>
  14 #include <linux/vmalloc.h>
  15 #include <linux/interrupt.h>
  16 #include <linux/bitops.h>
  17 #include <asm/semaphore.h>
  18
  19 #include <linux/firmware.h>
  20 #include "base.h"
  21
  22 MODULE_AUTHOR("Manuel Estrada Sainz <ranty@debian.org>");
  23 MODULE_DESCRIPTION("Multi purpose firmware loading support");
  24 MODULE_LICENSE("GPL");
  25
  26 enum {
  27         FW_STATUS_LOADING,
  28         FW_STATUS_DONE,
  29         FW_STATUS_ABORT,
  30         FW_STATUS_READY,
  31         FW_STATUS_READY_NOHOTPLUG,
  32 };
  33
  34 static int loading_timeout = 10;        /* In seconds */
  35
  36 /* fw_lock could be moved to 'struct firmware_priv' but since it is just
  37  * guarding for corner cases a global lock should be OK */
  38 static DECLARE_MUTEX(fw_lock);
  39
  40 struct firmware_priv {
  41         char fw_id[FIRMWARE_NAME_MAX];
  42         struct completion completion;
  43         struct bin_attribute attr_data;
  44         struct firmware *fw;
  45         unsigned long status;
  46         int alloc_size;
  47         struct timer_list timeout;
  48 };
  49
  50 static inline void
  51 fw_load_abort(struct firmware_priv *fw_priv)
  52 {
  53         set_bit(FW_STATUS_ABORT, &fw_priv->status);
  54         wmb();
  55         complete(&fw_priv->completion);
  56 }
  57
  58 static ssize_t
  59 firmware_timeout_show(struct class *class, char *buf)
  60 {
  61         return sprintf(buf, "%d\n", loading_timeout);
  62 }
  63
  64 /**
  65  * firmware_timeout_store:
  66  * Description:
  67  *      Sets the number of seconds to wait for the firmware.  Once
  68  *      this expires an error will be return to the driver and no
  69  *      firmware will be provided.
  70  *
  71  *      Note: zero means 'wait for ever'
  72  *
  73  **/
  74 static ssize_t
  75 firmware_timeout_store(struct class *class, const char *buf, size_t count)
  76 {
  77         loading_timeout = simple_strtol(buf, NULL, 10);
  78         if (loading_timeout < 0)
  79                 loading_timeout = 0;
  80         return count;
  81 }
  82
  83 static CLASS_ATTR(timeout, 0644, firmware_timeout_show, firmware_timeout_store);
  84
  85 static void  fw_class_dev_release(struct class_device *class_dev);
  86 int firmware_class_hotplug(struct class_device *dev, char **envp,
  87                            int num_envp, char *buffer, int buffer_size);
  88
  89 static struct class firmware_class = {
  90         .name           = "firmware",
  91         .hotplug        = firmware_class_hotplug,
  92         .release        = fw_class_dev_release,
  93 };
  94
  95 int
  96 firmware_class_hotplug(struct class_device *class_dev, char **envp,
  97                        int num_envp, char *buffer, int buffer_size)
  98 {
  99         struct firmware_priv *fw_priv = class_get_devdata(class_dev);
 100         int i = 0, len = 0;
 101
 102         if (!test_bit(FW_STATUS_READY, &fw_priv->status))
 103                 return -ENODEV;
 104
 105         if (add_hotplug_env_var(envp, num_envp, &i, buffer, buffer_size, &len,
 106                         "FIRMWARE=%s", fw_priv->fw_id))
 107                 return -ENOMEM;
 108         if (add_hotplug_env_var(envp, num_envp, &i, buffer, buffer_size, &len,
 109                         "TIMEOUT=%i", loading_timeout))
 110                 return -ENOMEM;
 111
 112         envp[i] = NULL;
 113
 114         return 0;
 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: - loading control file
 127  * Description:
 128  *      The relevant values are:
 129  *
 130  *       1: Start a load, discarding any previous partial load.
 131  *       0: Conclude the load and handle the data to the driver code.
 132  *      -1: Conclude the load with an error and discard any written data.
 133  **/
 134 static ssize_t
 135 firmware_loading_store(struct class_device *class_dev,
 136                        const char *buf, size_t count)
 137 {
 138         struct firmware_priv *fw_priv = class_get_devdata(class_dev);
 139         int loading = simple_strtol(buf, NULL, 10);
 140
 141         switch (loading) {
 142         case 1:
 143                 down(&fw_lock);
 144                 if (!fw_priv->fw) {
 145                         up(&fw_lock);
 146                         break;
 147                 }
 148                 vfree(fw_priv->fw->data);
 149                 fw_priv->fw->data = NULL;
 150                 fw_priv->fw->size = 0;
 151                 fw_priv->alloc_size = 0;
 152                 set_bit(FW_STATUS_LOADING, &fw_priv->status);
 153                 up(&fw_lock);
 154                 break;
 155         case 0:
 156                 if (test_bit(FW_STATUS_LOADING, &fw_priv->status)) {
 157                         complete(&fw_priv->completion);
 158                         clear_bit(FW_STATUS_LOADING, &fw_priv->status);
 159                         break;
 160                 }
 161                 /* fallthrough */
 162         default:
 163                 printk(KERN_ERR "%s: unexpected value (%d)\n", __FUNCTION__,
 164                        loading);
 165                 /* fallthrough */
 166         case -1:
 167                 fw_load_abort(fw_priv);
 168                 break;
 169         }
 170
 171         return count;
 172 }
 173
 174 static CLASS_DEVICE_ATTR(loading, 0644,
 175                         firmware_loading_show, firmware_loading_store);
 176
 177 static ssize_t
 178 firmware_data_read(struct kobject *kobj,
 179                    char *buffer, loff_t offset, size_t count)
 180 {
 181         struct class_device *class_dev = to_class_dev(kobj);
 182         struct firmware_priv *fw_priv = class_get_devdata(class_dev);
 183         struct firmware *fw;
 184         ssize_t ret_count = count;
 185
 186         down(&fw_lock);
 187         fw = fw_priv->fw;
 188         if (!fw || test_bit(FW_STATUS_DONE, &fw_priv->status)) {
 189                 ret_count = -ENODEV;
 190                 goto out;
 191         }
 192         if (offset > fw->size) {
 193                 ret_count = 0;
 194                 goto out;
 195         }
 196         if (offset + ret_count > fw->size)
 197                 ret_count = fw->size - offset;
 198
 199         memcpy(buffer, fw->data + offset, ret_count);
 200 out:
 201         up(&fw_lock);
 202         return ret_count;
 203 }
 204 static int
 205 fw_realloc_buffer(struct firmware_priv *fw_priv, int min_size)
 206 {
 207         u8 *new_data;
 208
 209         if (min_size <= fw_priv->alloc_size)
 210                 return 0;
 211
 212         new_data = vmalloc(fw_priv->alloc_size + PAGE_SIZE);
 213         if (!new_data) {
 214                 printk(KERN_ERR "%s: unable to alloc buffer\n", __FUNCTION__);
 215                 /* Make sure that we don't keep incomplete data */
 216                 fw_load_abort(fw_priv);
 217                 return -ENOMEM;
 218         }
 219         fw_priv->alloc_size += PAGE_SIZE;
 220         if (fw_priv->fw->data) {
 221                 memcpy(new_data, fw_priv->fw->data, fw_priv->fw->size);
 222                 vfree(fw_priv->fw->data);
 223         }
 224         fw_priv->fw->data = new_data;
 225         BUG_ON(min_size > fw_priv->alloc_size);
 226         return 0;
 227 }
 228
 229 /**
 230  * firmware_data_write:
 231  *
 232  * Description:
 233  *
 234  *      Data written to the 'data' attribute will be later handled to
 235  *      the driver as a firmware image.
 236  **/
 237 static ssize_t
 238 firmware_data_write(struct kobject *kobj,
 239                     char *buffer, loff_t offset, size_t count)
 240 {
 241         struct class_device *class_dev = to_class_dev(kobj);
 242         struct firmware_priv *fw_priv = class_get_devdata(class_dev);
 243         struct firmware *fw;
 244         ssize_t retval;
 245
 246         if (!capable(CAP_SYS_RAWIO))
 247                 return -EPERM;
 248
 249         down(&fw_lock);
 250         fw = fw_priv->fw;
 251         if (!fw || test_bit(FW_STATUS_DONE, &fw_priv->status)) {
 252                 retval = -ENODEV;
 253                 goto out;
 254         }
 255         retval = fw_realloc_buffer(fw_priv, offset + count);
 256         if (retval)
 257                 goto out;
 258
 259         memcpy(fw->data + offset, buffer, count);
 260
 261         fw->size = max_t(size_t, offset + count, fw->size);
 262         retval = count;
 263 out:
 264         up(&fw_lock);
 265         return retval;
 266 }
 267 static struct bin_attribute firmware_attr_data_tmpl = {
 268         .attr = {.name = "data", .mode = 0644, .owner = THIS_MODULE},
 269         .size = 0,
 270         .read = firmware_data_read,
 271         .write = firmware_data_write,
 272 };
 273
 274 static void
 275 fw_class_dev_release(struct class_device *class_dev)
 276 {
 277         struct firmware_priv *fw_priv = class_get_devdata(class_dev);
 278
 279         kfree(fw_priv);
 280         kfree(class_dev);
 281
 282         module_put(THIS_MODULE);
 283 }
 284
 285 static void
 286 firmware_class_timeout(u_long data)
 287 {
 288         struct firmware_priv *fw_priv = (struct firmware_priv *) data;
 289         fw_load_abort(fw_priv);
 290 }
 291
 292 static inline void
 293 fw_setup_class_device_id(struct class_device *class_dev, struct device *dev)
 294 {
 295         /* XXX warning we should watch out for name collisions */
 296         strlcpy(class_dev->class_id, dev->bus_id, BUS_ID_SIZE);
 297 }
 298
 299 static int
 300 fw_register_class_device(struct class_device **class_dev_p,
 301                          const char *fw_name, struct device *device)
 302 {
 303         int retval;
 304         struct firmware_priv *fw_priv = kmalloc(sizeof (struct firmware_priv),
 305                                                 GFP_KERNEL);
 306         struct class_device *class_dev = kmalloc(sizeof (struct class_device),
 307                                                  GFP_KERNEL);
 308
 309         *class_dev_p = NULL;
 310
 311         if (!fw_priv || !class_dev) {
 312                 printk(KERN_ERR "%s: kmalloc failed\n", __FUNCTION__);
 313                 retval = -ENOMEM;
 314                 goto error_kfree;
 315         }
 316         memset(fw_priv, 0, sizeof (*fw_priv));
 317         memset(class_dev, 0, sizeof (*class_dev));
 318
 319         init_completion(&fw_priv->completion);
 320         fw_priv->attr_data = firmware_attr_data_tmpl;
 321         strlcpy(fw_priv->fw_id, fw_name, FIRMWARE_NAME_MAX);
 322
 323         fw_priv->timeout.function = firmware_class_timeout;
 324         fw_priv->timeout.data = (u_long) fw_priv;
 325         init_timer(&fw_priv->timeout);
 326
 327         fw_setup_class_device_id(class_dev, device);
 328         class_dev->dev = device;
 329         class_dev->class = &firmware_class;
 330         class_set_devdata(class_dev, fw_priv);
 331         retval = class_device_register(class_dev);
 332         if (retval) {
 333                 printk(KERN_ERR "%s: class_device_register failed\n",
 334                        __FUNCTION__);
 335                 goto error_kfree;
 336         }
 337         *class_dev_p = class_dev;
 338         return 0;
 339
 340 error_kfree:
 341         kfree(fw_priv);
 342         kfree(class_dev);
 343         return retval;
 344 }
 345
 346 static int
 347 fw_setup_class_device(struct firmware *fw, struct class_device **class_dev_p,
 348                       const char *fw_name, struct device *device, int hotplug)
 349 {
 350         struct class_device *class_dev;
 351         struct firmware_priv *fw_priv;
 352         int retval;
 353
 354         *class_dev_p = NULL;
 355         retval = fw_register_class_device(&class_dev, fw_name, device);
 356         if (retval)
 357                 goto out;
 358
 359         /* Need to pin this module until class device is destroyed */
 360         __module_get(THIS_MODULE);
 361
 362         fw_priv = class_get_devdata(class_dev);
 363
 364         fw_priv->fw = fw;
 365         retval = sysfs_create_bin_file(&class_dev->kobj, &fw_priv->attr_data);
 366         if (retval) {
 367                 printk(KERN_ERR "%s: sysfs_create_bin_file failed\n",
 368                        __FUNCTION__);
 369                 goto error_unreg;
 370         }
 371
 372         retval = class_device_create_file(class_dev,
 373                                           &class_device_attr_loading);
 374         if (retval) {
 375                 printk(KERN_ERR "%s: class_device_create_file failed\n",
 376                        __FUNCTION__);
 377                 goto error_unreg;
 378         }
 379
 380         if (hotplug)
 381                 set_bit(FW_STATUS_READY, &fw_priv->status);
 382         else
 383                 set_bit(FW_STATUS_READY_NOHOTPLUG, &fw_priv->status);
 384         *class_dev_p = class_dev;
 385         goto out;
 386
 387 error_unreg:
 388         class_device_unregister(class_dev);
 389 out:
 390         return retval;
 391 }
 392
 393 static int
 394 _request_firmware(const struct firmware **firmware_p, const char *name,
 395                  struct device *device, int hotplug)
 396 {
 397         struct class_device *class_dev;
 398         struct firmware_priv *fw_priv;
 399         struct firmware *firmware;
 400         int retval;
 401
 402         if (!firmware_p)
 403                 return -EINVAL;
 404
 405         *firmware_p = firmware = kmalloc(sizeof (struct firmware), GFP_KERNEL);
 406         if (!firmware) {
 407                 printk(KERN_ERR "%s: kmalloc(struct firmware) failed\n",
 408                        __FUNCTION__);
 409                 retval = -ENOMEM;
 410                 goto out;
 411         }
 412         memset(firmware, 0, sizeof (*firmware));
 413
 414         retval = fw_setup_class_device(firmware, &class_dev, name, device,
 415                 hotplug);
 416         if (retval)
 417                 goto error_kfree_fw;
 418
 419         fw_priv = class_get_devdata(class_dev);
 420
 421         if (hotplug) {
 422                 if (loading_timeout > 0) {
 423                         fw_priv->timeout.expires = jiffies + loading_timeout * HZ;
 424                         add_timer(&fw_priv->timeout);
 425                 }
 426
 427                 kobject_hotplug(&class_dev->kobj, KOBJ_ADD);
 428                 wait_for_completion(&fw_priv->completion);
 429                 set_bit(FW_STATUS_DONE, &fw_priv->status);
 430                 del_timer_sync(&fw_priv->timeout);
 431         } else
 432                 wait_for_completion(&fw_priv->completion);
 433
 434         down(&fw_lock);
 435         if (!fw_priv->fw->size || test_bit(FW_STATUS_ABORT, &fw_priv->status)) {
 436                 retval = -ENOENT;
 437                 release_firmware(fw_priv->fw);
 438                 *firmware_p = NULL;
 439         }
 440         fw_priv->fw = NULL;
 441         up(&fw_lock);
 442         class_device_unregister(class_dev);
 443         goto out;
 444
 445 error_kfree_fw:
 446         kfree(firmware);
 447         *firmware_p = NULL;
 448 out:
 449         return retval;
 450 }
 451
 452 /**
 453  * request_firmware: - request firmware to hotplug and wait for it
 454  * Description:
 455  *      @firmware will be used to return a firmware image by the name
 456  *      of @name for device @device.
 457  *
 458  *      Should be called from user context where sleeping is allowed.
 459  *
 460  *      @name will be use as $FIRMWARE in the hotplug environment and
 461  *      should be distinctive enough not to be confused with any other
 462  *      firmware image for this or any other device.
 463  **/
 464 int
 465 request_firmware(const struct firmware **firmware_p, const char *name,
 466                  struct device *device)
 467 {
 468         int hotplug = 1;
 469         return _request_firmware(firmware_p, name, device, hotplug);
 470 }
 471
 472 /**
 473  * release_firmware: - release the resource associated with a firmware image
 474  **/
 475 void
 476 release_firmware(const struct firmware *fw)
 477 {
 478         if (fw) {
 479                 vfree(fw->data);
 480                 kfree(fw);
 481         }
 482 }
 483
 484 /**
 485  * register_firmware: - provide a firmware image for later usage
 486  *
 487  * Description:
 488  *      Make sure that @data will be available by requesting firmware @name.
 489  *
 490  *      Note: This will not be possible until some kind of persistence
 491  *      is available.
 492  **/
 493 void
 494 register_firmware(const char *name, const u8 *data, size_t size)
 495 {
 496         /* This is meaningless without firmware caching, so until we
 497          * decide if firmware caching is reasonable just leave it as a
 498          * noop */
 499 }
 500
 501 /* Async support */
 502 struct firmware_work {
 503         struct work_struct work;
 504         struct module *module;
 505         const char *name;
 506         struct device *device;
 507         void *context;
 508         void (*cont)(const struct firmware *fw, void *context);
 509         int hotplug;
 510 };
 511
 512 static int
 513 request_firmware_work_func(void *arg)
 514 {
 515         struct firmware_work *fw_work = arg;
 516         const struct firmware *fw;
 517         if (!arg) {
 518                 WARN_ON(1);
 519                 return 0;
 520         }
 521         daemonize("%s/%s", "firmware", fw_work->name);
 522         _request_firmware(&fw, fw_work->name, fw_work->device,
 523                 fw_work->hotplug);
 524         fw_work->cont(fw, fw_work->context);
 525         release_firmware(fw);
 526         module_put(fw_work->module);
 527         kfree(fw_work);
 528         return 0;
 529 }
 530
 531 /**
 532  * request_firmware_nowait:
 533  *
 534  * Description:
 535  *      Asynchronous variant of request_firmware() for contexts where
 536  *      it is not possible to sleep.
 537  *
 538  *      @hotplug invokes hotplug event to copy the firmware image if this flag
 539  *      is non-zero else the firmware copy must be done manually.
 540  *
 541  *      @cont will be called asynchronously when the firmware request is over.
 542  *
 543  *      @context will be passed over to @cont.
 544  *
 545  *      @fw may be %NULL if firmware request fails.
 546  *
 547  **/
 548 int
 549 request_firmware_nowait(
 550         struct module *module, int hotplug,
 551         const char *name, struct device *device, void *context,
 552         void (*cont)(const struct firmware *fw, void *context))
 553 {
 554         struct firmware_work *fw_work = kmalloc(sizeof (struct firmware_work),
 555                                                 GFP_ATOMIC);
 556         int ret;
 557
 558         if (!fw_work)
 559                 return -ENOMEM;
 560         if (!try_module_get(module)) {
 561                 kfree(fw_work);
 562                 return -EFAULT;
 563         }
 564
 565         *fw_work = (struct firmware_work) {
 566                 .module = module,
 567                 .name = name,
 568                 .device = device,
 569                 .context = context,
 570                 .cont = cont,
 571                 .hotplug = hotplug,
 572         };
 573
 574         ret = kernel_thread(request_firmware_work_func, fw_work,
 575                             CLONE_FS | CLONE_FILES);
 576
 577         if (ret < 0) {
 578                 fw_work->cont(NULL, fw_work->context);
 579                 return ret;
 580         }
 581         return 0;
 582 }
 583
 584 static int __init
 585 firmware_class_init(void)
 586 {
 587         int error;
 588         error = class_register(&firmware_class);
 589         if (error) {
 590                 printk(KERN_ERR "%s: class_register failed\n", __FUNCTION__);
 591                 return error;
 592         }
 593         error = class_create_file(&firmware_class, &class_attr_timeout);
 594         if (error) {
 595                 printk(KERN_ERR "%s: class_create_file failed\n",
 596                        __FUNCTION__);
 597                 class_unregister(&firmware_class);
 598         }
 599         return error;
 600
 601 }
 602 static void __exit
 603 firmware_class_exit(void)
 604 {
 605         class_unregister(&firmware_class);
 606 }
 607
 608 module_init(firmware_class_init);
 609 module_exit(firmware_class_exit);
 610
 611 EXPORT_SYMBOL(release_firmware);
 612 EXPORT_SYMBOL(request_firmware);
 613 EXPORT_SYMBOL(request_firmware_nowait);
 614 EXPORT_SYMBOL(register_firmware);