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   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         if (loading_timeout < 0)
  78                 loading_timeout = 0;
  79         return count;
  80 }
  81
  82 static CLASS_ATTR(timeout, 0644, firmware_timeout_show, firmware_timeout_store);
  83
  84 static void  fw_class_dev_release(struct class_device *class_dev);
  85 int firmware_class_hotplug(struct class_device *dev, char **envp,
  86                            int num_envp, char *buffer, int buffer_size);
  87
  88 static struct class firmware_class = {
  89         .name           = "firmware",
  90         .hotplug        = firmware_class_hotplug,
  91         .release        = fw_class_dev_release,
  92 };
  93
  94 int
  95 firmware_class_hotplug(struct class_device *class_dev, char **envp,
  96                        int num_envp, char *buffer, int buffer_size)
  97 {
  98         struct firmware_priv *fw_priv = class_get_devdata(class_dev);
  99         int i = 0, len = 0;
 100
 101         if (!test_bit(FW_STATUS_READY, &fw_priv->status))
 102                 return -ENODEV;
 103
 104         if (add_hotplug_env_var(envp, num_envp, &i, buffer, buffer_size, &len,
 105                         "FIRMWARE=%s", fw_priv->fw_id))
 106                 return -ENOMEM;
 107         if (add_hotplug_env_var(envp, num_envp, &i, buffer, buffer_size, &len,
 108                         "TIMEOUT=%i", loading_timeout))
 109                 return -ENOMEM;
 110
 111         envp[i] = NULL;
 112
 113         return 0;
 114 }
 115
 116 static ssize_t
 117 firmware_loading_show(struct class_device *class_dev, char *buf)
 118 {
 119         struct firmware_priv *fw_priv = class_get_devdata(class_dev);
 120         int loading = test_bit(FW_STATUS_LOADING, &fw_priv->status);
 121         return sprintf(buf, "%d\n", loading);
 122 }
 123
 124 /**
 125  * firmware_loading_store: - loading control file
 126  * Description:
 127  *      The relevant values are:
 128  *
 129  *       1: Start a load, discarding any previous partial load.
 130  *       0: Conclude the load and handle the data to the driver code.
 131  *      -1: Conclude the load with an error and discard any written data.
 132  **/
 133 static ssize_t
 134 firmware_loading_store(struct class_device *class_dev,
 135                        const char *buf, size_t count)
 136 {
 137         struct firmware_priv *fw_priv = class_get_devdata(class_dev);
 138         int loading = simple_strtol(buf, NULL, 10);
 139
 140         switch (loading) {
 141         case 1:
 142                 down(&fw_lock);
 143                 if (!fw_priv->fw) {
 144                         up(&fw_lock);
 145                         break;
 146                 }
 147                 vfree(fw_priv->fw->data);
 148                 fw_priv->fw->data = NULL;
 149                 fw_priv->fw->size = 0;
 150                 fw_priv->alloc_size = 0;
 151                 set_bit(FW_STATUS_LOADING, &fw_priv->status);
 152                 up(&fw_lock);
 153                 break;
 154         case 0:
 155                 if (test_bit(FW_STATUS_LOADING, &fw_priv->status)) {
 156                         complete(&fw_priv->completion);
 157                         clear_bit(FW_STATUS_LOADING, &fw_priv->status);
 158                         break;
 159                 }
 160                 /* fallthrough */
 161         default:
 162                 printk(KERN_ERR "%s: unexpected value (%d)\n", __FUNCTION__,
 163                        loading);
 164                 /* fallthrough */
 165         case -1:
 166                 fw_load_abort(fw_priv);
 167                 break;
 168         }
 169
 170         return count;
 171 }
 172
 173 static CLASS_DEVICE_ATTR(loading, 0644,
 174                         firmware_loading_show, firmware_loading_store);
 175
 176 static ssize_t
 177 firmware_data_read(struct kobject *kobj,
 178                    char *buffer, loff_t offset, size_t count)
 179 {
 180         struct class_device *class_dev = to_class_dev(kobj);
 181         struct firmware_priv *fw_priv = class_get_devdata(class_dev);
 182         struct firmware *fw;
 183         ssize_t ret_count = count;
 184
 185         down(&fw_lock);
 186         fw = fw_priv->fw;
 187         if (!fw || test_bit(FW_STATUS_DONE, &fw_priv->status)) {
 188                 ret_count = -ENODEV;
 189                 goto out;
 190         }
 191         if (offset > fw->size) {
 192                 ret_count = 0;
 193                 goto out;
 194         }
 195         if (offset + ret_count > fw->size)
 196                 ret_count = fw->size - offset;
 197
 198         memcpy(buffer, fw->data + offset, ret_count);
 199 out:
 200         up(&fw_lock);
 201         return ret_count;
 202 }
 203 static int
 204 fw_realloc_buffer(struct firmware_priv *fw_priv, int min_size)
 205 {
 206         u8 *new_data;
 207
 208         if (min_size <= fw_priv->alloc_size)
 209                 return 0;
 210
 211         new_data = vmalloc(fw_priv->alloc_size + PAGE_SIZE);
 212         if (!new_data) {
 213                 printk(KERN_ERR "%s: unable to alloc buffer\n", __FUNCTION__);
 214                 /* Make sure that we don't keep incomplete data */
 215                 fw_load_abort(fw_priv);
 216                 return -ENOMEM;
 217         }
 218         fw_priv->alloc_size += PAGE_SIZE;
 219         if (fw_priv->fw->data) {
 220                 memcpy(new_data, fw_priv->fw->data, fw_priv->fw->size);
 221                 vfree(fw_priv->fw->data);
 222         }
 223         fw_priv->fw->data = new_data;
 224         BUG_ON(min_size > fw_priv->alloc_size);
 225         return 0;
 226 }
 227
 228 /**
 229  * firmware_data_write:
 230  *
 231  * Description:
 232  *
 233  *      Data written to the 'data' attribute will be later handled to
 234  *      the driver as a firmware image.
 235  **/
 236 static ssize_t
 237 firmware_data_write(struct kobject *kobj,
 238                     char *buffer, loff_t offset, size_t count)
 239 {
 240         struct class_device *class_dev = to_class_dev(kobj);
 241         struct firmware_priv *fw_priv = class_get_devdata(class_dev);
 242         struct firmware *fw;
 243         ssize_t retval;
 244
 245         if (!capable(CAP_SYS_RAWIO))
 246                 return -EPERM;
 247
 248         down(&fw_lock);
 249         fw = fw_priv->fw;
 250         if (!fw || test_bit(FW_STATUS_DONE, &fw_priv->status)) {
 251                 retval = -ENODEV;
 252                 goto out;
 253         }
 254         retval = fw_realloc_buffer(fw_priv, offset + count);
 255         if (retval)
 256                 goto out;
 257
 258         memcpy(fw->data + offset, buffer, count);
 259
 260         fw->size = max_t(size_t, offset + count, fw->size);
 261         retval = count;
 262 out:
 263         up(&fw_lock);
 264         return retval;
 265 }
 266 static struct bin_attribute firmware_attr_data_tmpl = {
 267         .attr = {.name = "data", .mode = 0644, .owner = THIS_MODULE},
 268         .size = 0,
 269         .read = firmware_data_read,
 270         .write = firmware_data_write,
 271 };
 272
 273 static void
 274 fw_class_dev_release(struct class_device *class_dev)
 275 {
 276         struct firmware_priv *fw_priv = class_get_devdata(class_dev);
 277
 278         kfree(fw_priv);
 279         kfree(class_dev);
 280
 281         module_put(THIS_MODULE);
 282 }
 283
 284 static void
 285 firmware_class_timeout(u_long data)
 286 {
 287         struct firmware_priv *fw_priv = (struct firmware_priv *) data;
 288         fw_load_abort(fw_priv);
 289 }
 290
 291 static inline void
 292 fw_setup_class_device_id(struct class_device *class_dev, struct device *dev)
 293 {
 294         /* XXX warning we should watch out for name collisions */
 295         strlcpy(class_dev->class_id, dev->bus_id, BUS_ID_SIZE);
 296 }
 297
 298 static int
 299 fw_register_class_device(struct class_device **class_dev_p,
 300                          const char *fw_name, struct device *device)
 301 {
 302         int retval;
 303         struct firmware_priv *fw_priv = kmalloc(sizeof (struct firmware_priv),
 304                                                 GFP_KERNEL);
 305         struct class_device *class_dev = kmalloc(sizeof (struct class_device),
 306                                                  GFP_KERNEL);
 307
 308         *class_dev_p = NULL;
 309
 310         if (!fw_priv || !class_dev) {
 311                 printk(KERN_ERR "%s: kmalloc failed\n", __FUNCTION__);
 312                 retval = -ENOMEM;
 313                 goto error_kfree;
 314         }
 315         memset(fw_priv, 0, sizeof (*fw_priv));
 316         memset(class_dev, 0, sizeof (*class_dev));
 317
 318         init_completion(&fw_priv->completion);
 319         fw_priv->attr_data = firmware_attr_data_tmpl;
 320         strlcpy(fw_priv->fw_id, fw_name, FIRMWARE_NAME_MAX);
 321
 322         fw_priv->timeout.function = firmware_class_timeout;
 323         fw_priv->timeout.data = (u_long) fw_priv;
 324         init_timer(&fw_priv->timeout);
 325
 326         fw_setup_class_device_id(class_dev, device);
 327         class_dev->dev = device;
 328         class_dev->class = &firmware_class;
 329         class_set_devdata(class_dev, fw_priv);
 330         retval = class_device_register(class_dev);
 331         if (retval) {
 332                 printk(KERN_ERR "%s: class_device_register failed\n",
 333                        __FUNCTION__);
 334                 goto error_kfree;
 335         }
 336         *class_dev_p = class_dev;
 337         return 0;
 338
 339 error_kfree:
 340         kfree(fw_priv);
 341         kfree(class_dev);
 342         return retval;
 343 }
 344
 345 static int
 346 fw_setup_class_device(struct firmware *fw, struct class_device **class_dev_p,
 347                       const char *fw_name, struct device *device)
 348 {
 349         struct class_device *class_dev;
 350         struct firmware_priv *fw_priv;
 351         int retval;
 352
 353         *class_dev_p = NULL;
 354         retval = fw_register_class_device(&class_dev, fw_name, device);
 355         if (retval)
 356                 goto out;
 357
 358         /* Need to pin this module until class device is destroyed */
 359         __module_get(THIS_MODULE);
 360
 361         fw_priv = class_get_devdata(class_dev);
 362
 363         fw_priv->fw = fw;
 364         retval = sysfs_create_bin_file(&class_dev->kobj, &fw_priv->attr_data);
 365         if (retval) {
 366                 printk(KERN_ERR "%s: sysfs_create_bin_file failed\n",
 367                        __FUNCTION__);
 368                 goto error_unreg;
 369         }
 370
 371         retval = class_device_create_file(class_dev,
 372                                           &class_device_attr_loading);
 373         if (retval) {
 374                 printk(KERN_ERR "%s: class_device_create_file failed\n",
 375                        __FUNCTION__);
 376                 goto error_unreg;
 377         }
 378
 379         set_bit(FW_STATUS_READY, &fw_priv->status);
 380         *class_dev_p = class_dev;
 381         goto out;
 382
 383 error_unreg:
 384         class_device_unregister(class_dev);
 385 out:
 386         return retval;
 387 }
 388
 389 /**
 390  * request_firmware: - request firmware to hotplug and wait for it
 391  * Description:
 392  *      @firmware will be used to return a firmware image by the name
 393  *      of @name for device @device.
 394  *
 395  *      Should be called from user context where sleeping is allowed.
 396  *
 397  *      @name will be use as $FIRMWARE in the hotplug environment and
 398  *      should be distinctive enough not to be confused with any other
 399  *      firmware image for this or any other device.
 400  **/
 401 int
 402 request_firmware(const struct firmware **firmware_p, const char *name,
 403                  struct device *device)
 404 {
 405         struct class_device *class_dev;
 406         struct firmware_priv *fw_priv;
 407         struct firmware *firmware;
 408         int retval;
 409
 410         if (!firmware_p)
 411                 return -EINVAL;
 412
 413         *firmware_p = firmware = kmalloc(sizeof (struct firmware), GFP_KERNEL);
 414         if (!firmware) {
 415                 printk(KERN_ERR "%s: kmalloc(struct firmware) failed\n",
 416                        __FUNCTION__);
 417                 retval = -ENOMEM;
 418                 goto out;
 419         }
 420         memset(firmware, 0, sizeof (*firmware));
 421
 422         retval = fw_setup_class_device(firmware, &class_dev, name, device);
 423         if (retval)
 424                 goto error_kfree_fw;
 425
 426         fw_priv = class_get_devdata(class_dev);
 427
 428         if (loading_timeout > 0) {
 429                 fw_priv->timeout.expires = jiffies + loading_timeout * HZ;
 430                 add_timer(&fw_priv->timeout);
 431         }
 432
 433         kobject_hotplug(&class_dev->kobj, KOBJ_ADD);
 434         wait_for_completion(&fw_priv->completion);
 435         set_bit(FW_STATUS_DONE, &fw_priv->status);
 436
 437         del_timer_sync(&fw_priv->timeout);
 438
 439         down(&fw_lock);
 440         if (!fw_priv->fw->size || test_bit(FW_STATUS_ABORT, &fw_priv->status)) {
 441                 retval = -ENOENT;
 442                 release_firmware(fw_priv->fw);
 443                 *firmware_p = NULL;
 444         }
 445         fw_priv->fw = NULL;
 446         up(&fw_lock);
 447         class_device_unregister(class_dev);
 448         goto out;
 449
 450 error_kfree_fw:
 451         kfree(firmware);
 452         *firmware_p = NULL;
 453 out:
 454         return retval;
 455 }
 456
 457 /**
 458  * release_firmware: - release the resource associated with a firmware image
 459  **/
 460 void
 461 release_firmware(const struct firmware *fw)
 462 {
 463         if (fw) {
 464                 vfree(fw->data);
 465                 kfree(fw);
 466         }
 467 }
 468
 469 /**
 470  * register_firmware: - provide a firmware image for later usage
 471  *
 472  * Description:
 473  *      Make sure that @data will be available by requesting firmware @name.
 474  *
 475  *      Note: This will not be possible until some kind of persistence
 476  *      is available.
 477  **/
 478 void
 479 register_firmware(const char *name, const u8 *data, size_t size)
 480 {
 481         /* This is meaningless without firmware caching, so until we
 482          * decide if firmware caching is reasonable just leave it as a
 483          * noop */
 484 }
 485
 486 /* Async support */
 487 struct firmware_work {
 488         struct work_struct work;
 489         struct module *module;
 490         const char *name;
 491         struct device *device;
 492         void *context;
 493         void (*cont)(const struct firmware *fw, void *context);
 494 };
 495
 496 static int
 497 request_firmware_work_func(void *arg)
 498 {
 499         struct firmware_work *fw_work = arg;
 500         const struct firmware *fw;
 501         if (!arg) {
 502                 WARN_ON(1);
 503                 return 0;
 504         }
 505         daemonize("%s/%s", "firmware", fw_work->name);
 506         request_firmware(&fw, fw_work->name, fw_work->device);
 507         fw_work->cont(fw, fw_work->context);
 508         release_firmware(fw);
 509         module_put(fw_work->module);
 510         kfree(fw_work);
 511         return 0;
 512 }
 513
 514 /**
 515  * request_firmware_nowait:
 516  *
 517  * Description:
 518  *      Asynchronous variant of request_firmware() for contexts where
 519  *      it is not possible to sleep.
 520  *
 521  *      @cont will be called asynchronously when the firmware request is over.
 522  *
 523  *      @context will be passed over to @cont.
 524  *
 525  *      @fw may be %NULL if firmware request fails.
 526  *
 527  **/
 528 int
 529 request_firmware_nowait(
 530         struct module *module,
 531         const char *name, struct device *device, void *context,
 532         void (*cont)(const struct firmware *fw, void *context))
 533 {
 534         struct firmware_work *fw_work = kmalloc(sizeof (struct firmware_work),
 535                                                 GFP_ATOMIC);
 536         int ret;
 537
 538         if (!fw_work)
 539                 return -ENOMEM;
 540         if (!try_module_get(module)) {
 541                 kfree(fw_work);
 542                 return -EFAULT;
 543         }
 544
 545         *fw_work = (struct firmware_work) {
 546                 .module = module,
 547                 .name = name,
 548                 .device = device,
 549                 .context = context,
 550                 .cont = cont,
 551         };
 552
 553         ret = kernel_thread(request_firmware_work_func, fw_work,
 554                             CLONE_FS | CLONE_FILES);
 555
 556         if (ret < 0) {
 557                 fw_work->cont(NULL, fw_work->context);
 558                 return ret;
 559         }
 560         return 0;
 561 }
 562
 563 static int __init
 564 firmware_class_init(void)
 565 {
 566         int error;
 567         error = class_register(&firmware_class);
 568         if (error) {
 569                 printk(KERN_ERR "%s: class_register failed\n", __FUNCTION__);
 570                 return error;
 571         }
 572         error = class_create_file(&firmware_class, &class_attr_timeout);
 573         if (error) {
 574                 printk(KERN_ERR "%s: class_create_file failed\n",
 575                        __FUNCTION__);
 576                 class_unregister(&firmware_class);
 577         }
 578         return error;
 579
 580 }
 581 static void __exit
 582 firmware_class_exit(void)
 583 {
 584         class_unregister(&firmware_class);
 585 }
 586
 587 module_init(firmware_class_init);
 588 module_exit(firmware_class_exit);
 589
 590 EXPORT_SYMBOL(release_firmware);
 591 EXPORT_SYMBOL(request_firmware);
 592 EXPORT_SYMBOL(request_firmware_nowait);
 593 EXPORT_SYMBOL(register_firmware);