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 };
  32
  33 static int loading_timeout = 10;        /* In seconds */
  34
  35 /* fw_lock could be moved to 'struct firmware_priv' but since it is just
  36  * guarding for corner cases a global lock should be OK */
  37 static DECLARE_MUTEX(fw_lock);
  38
  39 struct firmware_priv {
  40         char fw_id[FIRMWARE_NAME_MAX];
  41         struct completion completion;
  42         struct bin_attribute attr_data;
  43         struct firmware *fw;
  44         unsigned long status;
  45         int alloc_size;
  46         struct timer_list timeout;
  47 };
  48
  49 static inline void
  50 fw_load_abort(struct firmware_priv *fw_priv)
  51 {
  52         set_bit(FW_STATUS_ABORT, &fw_priv->status);
  53         wmb();
  54         complete(&fw_priv->completion);
  55 }
  56
  57 static ssize_t
  58 firmware_timeout_show(struct class *class, char *buf)
  59 {
  60         return sprintf(buf, "%d\n", loading_timeout);
  61 }
  62
  63 /**
  64  * firmware_timeout_store:
  65  * Description:
  66  *      Sets the number of seconds to wait for the firmware.  Once
  67  *      this expires an error will be return to the driver and no
  68  *      firmware will be provided.
  69  *
  70  *      Note: zero means 'wait for ever'
  71  *
  72  **/
  73 static ssize_t
  74 firmware_timeout_store(struct class *class, const char *buf, size_t count)
  75 {
  76         loading_timeout = simple_strtol(buf, NULL, 10);
  77         return count;
  78 }
  79
  80 static CLASS_ATTR(timeout, 0644, firmware_timeout_show, firmware_timeout_store);
  81
  82 static void  fw_class_dev_release(struct class_device *class_dev);
  83 int firmware_class_hotplug(struct class_device *dev, char **envp,
  84                            int num_envp, char *buffer, int buffer_size);
  85
  86 static struct class firmware_class = {
  87         .name           = "firmware",
  88         .hotplug        = firmware_class_hotplug,
  89         .release        = fw_class_dev_release,
  90 };
  91
  92 int
  93 firmware_class_hotplug(struct class_device *class_dev, char **envp,
  94                        int num_envp, char *buffer, int buffer_size)
  95 {
  96         struct firmware_priv *fw_priv = class_get_devdata(class_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_hotplug_env_var(envp, num_envp, &i, buffer, buffer_size, &len,
 103                         "FIRMWARE=%s", fw_priv->fw_id))
 104                 return -ENOMEM;
 105         if (add_hotplug_env_var(envp, num_envp, &i, buffer, buffer_size, &len,
 106                         "TIMEOUT=%i", loading_timeout))
 107                 return -ENOMEM;
 108
 109         envp[i] = NULL;
 110
 111         return 0;
 112 }
 113
 114 static ssize_t
 115 firmware_loading_show(struct class_device *class_dev, char *buf)
 116 {
 117         struct firmware_priv *fw_priv = class_get_devdata(class_dev);
 118         int loading = test_bit(FW_STATUS_LOADING, &fw_priv->status);
 119         return sprintf(buf, "%d\n", loading);
 120 }
 121
 122 /**
 123  * firmware_loading_store: - loading control file
 124  * Description:
 125  *      The relevant values are:
 126  *
 127  *       1: Start a load, discarding any previous partial load.
 128  *       0: Conclude the load and handle the data to the driver code.
 129  *      -1: Conclude the load with an error and discard any written data.
 130  **/
 131 static ssize_t
 132 firmware_loading_store(struct class_device *class_dev,
 133                        const char *buf, size_t count)
 134 {
 135         struct firmware_priv *fw_priv = class_get_devdata(class_dev);
 136         int loading = simple_strtol(buf, NULL, 10);
 137
 138         switch (loading) {
 139         case 1:
 140                 down(&fw_lock);
 141                 vfree(fw_priv->fw->data);
 142                 fw_priv->fw->data = NULL;
 143                 fw_priv->fw->size = 0;
 144                 fw_priv->alloc_size = 0;
 145                 set_bit(FW_STATUS_LOADING, &fw_priv->status);
 146                 up(&fw_lock);
 147                 break;
 148         case 0:
 149                 if (test_bit(FW_STATUS_LOADING, &fw_priv->status)) {
 150                         complete(&fw_priv->completion);
 151                         clear_bit(FW_STATUS_LOADING, &fw_priv->status);
 152                         break;
 153                 }
 154                 /* fallthrough */
 155         default:
 156                 printk(KERN_ERR "%s: unexpected value (%d)\n", __FUNCTION__,
 157                        loading);
 158                 /* fallthrough */
 159         case -1:
 160                 fw_load_abort(fw_priv);
 161                 break;
 162         }
 163
 164         return count;
 165 }
 166
 167 static CLASS_DEVICE_ATTR(loading, 0644,
 168                         firmware_loading_show, firmware_loading_store);
 169
 170 static ssize_t
 171 firmware_data_read(struct kobject *kobj,
 172                    char *buffer, loff_t offset, size_t count)
 173 {
 174         struct class_device *class_dev = to_class_dev(kobj);
 175         struct firmware_priv *fw_priv = class_get_devdata(class_dev);
 176         struct firmware *fw;
 177         ssize_t ret_count = count;
 178
 179         down(&fw_lock);
 180         fw = fw_priv->fw;
 181         if (test_bit(FW_STATUS_DONE, &fw_priv->status)) {
 182                 ret_count = -ENODEV;
 183                 goto out;
 184         }
 185         if (offset > fw->size) {
 186                 ret_count = 0;
 187                 goto out;
 188         }
 189         if (offset + ret_count > fw->size)
 190                 ret_count = fw->size - offset;
 191
 192         memcpy(buffer, fw->data + offset, ret_count);
 193 out:
 194         up(&fw_lock);
 195         return ret_count;
 196 }
 197 static int
 198 fw_realloc_buffer(struct firmware_priv *fw_priv, int min_size)
 199 {
 200         u8 *new_data;
 201
 202         if (min_size <= fw_priv->alloc_size)
 203                 return 0;
 204
 205         new_data = vmalloc(fw_priv->alloc_size + PAGE_SIZE);
 206         if (!new_data) {
 207                 printk(KERN_ERR "%s: unable to alloc buffer\n", __FUNCTION__);
 208                 /* Make sure that we don't keep incomplete data */
 209                 fw_load_abort(fw_priv);
 210                 return -ENOMEM;
 211         }
 212         fw_priv->alloc_size += PAGE_SIZE;
 213         if (fw_priv->fw->data) {
 214                 memcpy(new_data, fw_priv->fw->data, fw_priv->fw->size);
 215                 vfree(fw_priv->fw->data);
 216         }
 217         fw_priv->fw->data = new_data;
 218         BUG_ON(min_size > fw_priv->alloc_size);
 219         return 0;
 220 }
 221
 222 /**
 223  * firmware_data_write:
 224  *
 225  * Description:
 226  *
 227  *      Data written to the 'data' attribute will be later handled to
 228  *      the driver as a firmware image.
 229  **/
 230 static ssize_t
 231 firmware_data_write(struct kobject *kobj,
 232                     char *buffer, loff_t offset, size_t count)
 233 {
 234         struct class_device *class_dev = to_class_dev(kobj);
 235         struct firmware_priv *fw_priv = class_get_devdata(class_dev);
 236         struct firmware *fw;
 237         ssize_t retval;
 238
 239         if (!capable(CAP_SYS_RAWIO))
 240                 return -EPERM;
 241         down(&fw_lock);
 242         fw = fw_priv->fw;
 243         if (test_bit(FW_STATUS_DONE, &fw_priv->status)) {
 244                 retval = -ENODEV;
 245                 goto out;
 246         }
 247         retval = fw_realloc_buffer(fw_priv, offset + count);
 248         if (retval)
 249                 goto out;
 250
 251         memcpy(fw->data + offset, buffer, count);
 252
 253         fw->size = max_t(size_t, offset + count, fw->size);
 254         retval = count;
 255 out:
 256         up(&fw_lock);
 257         return retval;
 258 }
 259 static struct bin_attribute firmware_attr_data_tmpl = {
 260         .attr = {.name = "data", .mode = 0644, .owner = THIS_MODULE},
 261         .size = 0,
 262         .read = firmware_data_read,
 263         .write = firmware_data_write,
 264 };
 265
 266 static void
 267 fw_class_dev_release(struct class_device *class_dev)
 268 {
 269         struct firmware_priv *fw_priv = class_get_devdata(class_dev);
 270
 271         kfree(fw_priv);
 272         kfree(class_dev);
 273
 274         module_put(THIS_MODULE);
 275 }
 276
 277 static void
 278 firmware_class_timeout(u_long data)
 279 {
 280         struct firmware_priv *fw_priv = (struct firmware_priv *) data;
 281         fw_load_abort(fw_priv);
 282 }
 283
 284 static inline void
 285 fw_setup_class_device_id(struct class_device *class_dev, struct device *dev)
 286 {
 287         /* XXX warning we should watch out for name collisions */
 288         strlcpy(class_dev->class_id, dev->bus_id, BUS_ID_SIZE);
 289 }
 290
 291 static int
 292 fw_register_class_device(struct class_device **class_dev_p,
 293                          const char *fw_name, struct device *device)
 294 {
 295         int retval;
 296         struct firmware_priv *fw_priv = kmalloc(sizeof (struct firmware_priv),
 297                                                 GFP_KERNEL);
 298         struct class_device *class_dev = kmalloc(sizeof (struct class_device),
 299                                                  GFP_KERNEL);
 300
 301         *class_dev_p = NULL;
 302
 303         if (!fw_priv || !class_dev) {
 304                 printk(KERN_ERR "%s: kmalloc failed\n", __FUNCTION__);
 305                 retval = -ENOMEM;
 306                 goto error_kfree;
 307         }
 308         memset(fw_priv, 0, sizeof (*fw_priv));
 309         memset(class_dev, 0, sizeof (*class_dev));
 310
 311         init_completion(&fw_priv->completion);
 312         fw_priv->attr_data = firmware_attr_data_tmpl;
 313         strlcpy(fw_priv->fw_id, fw_name, FIRMWARE_NAME_MAX);
 314
 315         fw_priv->timeout.function = firmware_class_timeout;
 316         fw_priv->timeout.data = (u_long) fw_priv;
 317         init_timer(&fw_priv->timeout);
 318
 319         fw_setup_class_device_id(class_dev, device);
 320         class_dev->dev = device;
 321         class_dev->class = &firmware_class;
 322         class_set_devdata(class_dev, fw_priv);
 323         retval = class_device_register(class_dev);
 324         if (retval) {
 325                 printk(KERN_ERR "%s: class_device_register failed\n",
 326                        __FUNCTION__);
 327                 goto error_kfree;
 328         }
 329         *class_dev_p = class_dev;
 330         return 0;
 331
 332 error_kfree:
 333         kfree(fw_priv);
 334         kfree(class_dev);
 335         return retval;
 336 }
 337
 338 static int
 339 fw_setup_class_device(struct firmware *fw, struct class_device **class_dev_p,
 340                       const char *fw_name, struct device *device)
 341 {
 342         struct class_device *class_dev;
 343         struct firmware_priv *fw_priv;
 344         int retval;
 345
 346         *class_dev_p = NULL;
 347         retval = fw_register_class_device(&class_dev, fw_name, device);
 348         if (retval)
 349                 goto out;
 350
 351         /* Need to pin this module until class device is destroyed */
 352         __module_get(THIS_MODULE);
 353
 354         fw_priv = class_get_devdata(class_dev);
 355
 356         fw_priv->fw = fw;
 357         retval = sysfs_create_bin_file(&class_dev->kobj, &fw_priv->attr_data);
 358         if (retval) {
 359                 printk(KERN_ERR "%s: sysfs_create_bin_file failed\n",
 360                        __FUNCTION__);
 361                 goto error_unreg;
 362         }
 363
 364         retval = class_device_create_file(class_dev,
 365                                           &class_device_attr_loading);
 366         if (retval) {
 367                 printk(KERN_ERR "%s: class_device_create_file failed\n",
 368                        __FUNCTION__);
 369                 goto error_unreg;
 370         }
 371
 372         set_bit(FW_STATUS_READY, &fw_priv->status);
 373         *class_dev_p = class_dev;
 374         goto out;
 375
 376 error_unreg:
 377         class_device_unregister(class_dev);
 378 out:
 379         return retval;
 380 }
 381
 382 /**
 383  * request_firmware: - request firmware to hotplug and wait for it
 384  * Description:
 385  *      @firmware will be used to return a firmware image by the name
 386  *      of @name for device @device.
 387  *
 388  *      Should be called from user context where sleeping is allowed.
 389  *
 390  *      @name will be use as $FIRMWARE in the hotplug environment and
 391  *      should be distinctive enough not to be confused with any other
 392  *      firmware image for this or any other device.
 393  **/
 394 int
 395 request_firmware(const struct firmware **firmware_p, const char *name,
 396                  struct device *device)
 397 {
 398         struct class_device *class_dev;
 399         struct firmware_priv *fw_priv;
 400         struct firmware *firmware;
 401         int retval;
 402
 403         if (!firmware_p)
 404                 return -EINVAL;
 405
 406         *firmware_p = firmware = kmalloc(sizeof (struct firmware), GFP_KERNEL);
 407         if (!firmware) {
 408                 printk(KERN_ERR "%s: kmalloc(struct firmware) failed\n",
 409                        __FUNCTION__);
 410                 retval = -ENOMEM;
 411                 goto out;
 412         }
 413         memset(firmware, 0, sizeof (*firmware));
 414
 415         retval = fw_setup_class_device(firmware, &class_dev, name, device);
 416         if (retval)
 417                 goto error_kfree_fw;
 418
 419         fw_priv = class_get_devdata(class_dev);
 420
 421         if (loading_timeout) {
 422                 fw_priv->timeout.expires = jiffies + loading_timeout * HZ;
 423                 add_timer(&fw_priv->timeout);
 424         }
 425
 426         kobject_hotplug(&class_dev->kobj, KOBJ_ADD);
 427         wait_for_completion(&fw_priv->completion);
 428         set_bit(FW_STATUS_DONE, &fw_priv->status);
 429
 430         del_timer_sync(&fw_priv->timeout);
 431
 432         down(&fw_lock);
 433         if (!fw_priv->fw->size || test_bit(FW_STATUS_ABORT, &fw_priv->status)) {
 434                 retval = -ENOENT;
 435                 release_firmware(fw_priv->fw);
 436                 *firmware_p = NULL;
 437         }
 438         fw_priv->fw = NULL;
 439         up(&fw_lock);
 440         class_device_unregister(class_dev);
 441         goto out;
 442
 443 error_kfree_fw:
 444         kfree(firmware);
 445         *firmware_p = NULL;
 446 out:
 447         return retval;
 448 }
 449
 450 /**
 451  * release_firmware: - release the resource associated with a firmware image
 452  **/
 453 void
 454 release_firmware(const struct firmware *fw)
 455 {
 456         if (fw) {
 457                 vfree(fw->data);
 458                 kfree(fw);
 459         }
 460 }
 461
 462 /**
 463  * register_firmware: - provide a firmware image for later usage
 464  *
 465  * Description:
 466  *      Make sure that @data will be available by requesting firmware @name.
 467  *
 468  *      Note: This will not be possible until some kind of persistence
 469  *      is available.
 470  **/
 471 void
 472 register_firmware(const char *name, const u8 *data, size_t size)
 473 {
 474         /* This is meaningless without firmware caching, so until we
 475          * decide if firmware caching is reasonable just leave it as a
 476          * noop */
 477 }
 478
 479 /* Async support */
 480 struct firmware_work {
 481         struct work_struct work;
 482         struct module *module;
 483         const char *name;
 484         struct device *device;
 485         void *context;
 486         void (*cont)(const struct firmware *fw, void *context);
 487 };
 488
 489 static int
 490 request_firmware_work_func(void *arg)
 491 {
 492         struct firmware_work *fw_work = arg;
 493         const struct firmware *fw;
 494         if (!arg) {
 495                 WARN_ON(1);
 496                 return 0;
 497         }
 498         daemonize("%s/%s", "firmware", fw_work->name);
 499         request_firmware(&fw, fw_work->name, fw_work->device);
 500         fw_work->cont(fw, fw_work->context);
 501         release_firmware(fw);
 502         module_put(fw_work->module);
 503         kfree(fw_work);
 504         return 0;
 505 }
 506
 507 /**
 508  * request_firmware_nowait:
 509  *
 510  * Description:
 511  *      Asynchronous variant of request_firmware() for contexts where
 512  *      it is not possible to sleep.
 513  *
 514  *      @cont will be called asynchronously when the firmware request is over.
 515  *
 516  *      @context will be passed over to @cont.
 517  *
 518  *      @fw may be %NULL if firmware request fails.
 519  *
 520  **/
 521 int
 522 request_firmware_nowait(
 523         struct module *module,
 524         const char *name, struct device *device, void *context,
 525         void (*cont)(const struct firmware *fw, void *context))
 526 {
 527         struct firmware_work *fw_work = kmalloc(sizeof (struct firmware_work),
 528                                                 GFP_ATOMIC);
 529         int ret;
 530
 531         if (!fw_work)
 532                 return -ENOMEM;
 533         if (!try_module_get(module)) {
 534                 kfree(fw_work);
 535                 return -EFAULT;
 536         }
 537
 538         *fw_work = (struct firmware_work) {
 539                 .module = module,
 540                 .name = name,
 541                 .device = device,
 542                 .context = context,
 543                 .cont = cont,
 544         };
 545
 546         ret = kernel_thread(request_firmware_work_func, fw_work,
 547                             CLONE_FS | CLONE_FILES);
 548
 549         if (ret < 0) {
 550                 fw_work->cont(NULL, fw_work->context);
 551                 return ret;
 552         }
 553         return 0;
 554 }
 555
 556 static int __init
 557 firmware_class_init(void)
 558 {
 559         int error;
 560         error = class_register(&firmware_class);
 561         if (error) {
 562                 printk(KERN_ERR "%s: class_register failed\n", __FUNCTION__);
 563                 return error;
 564         }
 565         error = class_create_file(&firmware_class, &class_attr_timeout);
 566         if (error) {
 567                 printk(KERN_ERR "%s: class_create_file failed\n",
 568                        __FUNCTION__);
 569                 class_unregister(&firmware_class);
 570         }
 571         return error;
 572
 573 }
 574 static void __exit
 575 firmware_class_exit(void)
 576 {
 577         class_unregister(&firmware_class);
 578 }
 579
 580 module_init(firmware_class_init);
 581 module_exit(firmware_class_exit);
 582
 583 EXPORT_SYMBOL(release_firmware);
 584 EXPORT_SYMBOL(request_firmware);
 585 EXPORT_SYMBOL(request_firmware_nowait);
 586 EXPORT_SYMBOL(register_firmware);