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