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