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/capability.h>
  11 #include <linux/device.h>
  12 #include <linux/module.h>
  13 #include <linux/init.h>
  14 #include <linux/timer.h>
  15 #include <linux/vmalloc.h>
  16 #include <linux/interrupt.h>
  17 #include <linux/bitops.h>
  18 #include <linux/mutex.h>
  19 #include <linux/kthread.h>
  20
  21 #include <linux/firmware.h>
  22 #include "base.h"
  23
  24 #define to_dev(obj) container_of(obj, struct device, kobj)
  25
  26 MODULE_AUTHOR("Manuel Estrada Sainz <ranty@debian.org>");
  27 MODULE_DESCRIPTION("Multi purpose firmware loading support");
  28 MODULE_LICENSE("GPL");
  29
  30 enum {
  31         FW_STATUS_LOADING,
  32         FW_STATUS_DONE,
  33         FW_STATUS_ABORT,
  34         FW_STATUS_READY,
  35         FW_STATUS_READY_NOHOTPLUG,
  36 };
  37
  38 static int loading_timeout = 10;        /* In seconds */
  39
  40 /* fw_lock could be moved to 'struct firmware_priv' but since it is just
  41  * guarding for corner cases a global lock should be OK */
  42 static DEFINE_MUTEX(fw_lock);
  43
  44 struct firmware_priv {
  45         char fw_id[FIRMWARE_NAME_MAX];
  46         struct completion completion;
  47         struct bin_attribute attr_data;
  48         struct firmware *fw;
  49         unsigned long status;
  50         int alloc_size;
  51         struct timer_list timeout;
  52 };
  53
  54 static void
  55 fw_load_abort(struct firmware_priv *fw_priv)
  56 {
  57         set_bit(FW_STATUS_ABORT, &fw_priv->status);
  58         wmb();
  59         complete(&fw_priv->completion);
  60 }
  61
  62 static ssize_t
  63 firmware_timeout_show(struct class *class, char *buf)
  64 {
  65         return sprintf(buf, "%d\n", loading_timeout);
  66 }
  67
  68 /**
  69  * firmware_timeout_store - set number of seconds to wait for firmware
  70  * @class: device class pointer
  71  * @buf: buffer to scan for timeout value
  72  * @count: number of bytes in @buf
  73  *
  74  *      Sets the number of seconds to wait for the firmware.  Once
  75  *      this expires an error will be returned to the driver and no
  76  *      firmware will be provided.
  77  *
  78  *      Note: zero means 'wait forever'.
  79  **/
  80 static ssize_t
  81 firmware_timeout_store(struct class *class, const char *buf, size_t count)
  82 {
  83         loading_timeout = simple_strtol(buf, NULL, 10);
  84         if (loading_timeout < 0)
  85                 loading_timeout = 0;
  86         return count;
  87 }
  88
  89 static CLASS_ATTR(timeout, 0644, firmware_timeout_show, firmware_timeout_store);
  90
  91 static void fw_dev_release(struct device *dev);
  92
  93 static int firmware_uevent(struct device *dev, char **envp, int num_envp,
  94                            char *buffer, int buffer_size)
  95 {
  96         struct firmware_priv *fw_priv = dev_get_drvdata(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_uevent_var(envp, num_envp, &i, buffer, buffer_size, &len,
 103                            "FIRMWARE=%s", fw_priv->fw_id))
 104                 return -ENOMEM;
 105         if (add_uevent_var(envp, num_envp, &i, buffer, buffer_size, &len,
 106                            "TIMEOUT=%i", loading_timeout))
 107                 return -ENOMEM;
 108         envp[i] = NULL;
 109
 110         return 0;
 111 }
 112
 113 static struct class firmware_class = {
 114         .name           = "firmware",
 115         .dev_uevent     = firmware_uevent,
 116         .dev_release    = fw_dev_release,
 117 };
 118
 119 static ssize_t firmware_loading_show(struct device *dev,
 120                                      struct device_attribute *attr, char *buf)
 121 {
 122         struct firmware_priv *fw_priv = dev_get_drvdata(dev);
 123         int loading = test_bit(FW_STATUS_LOADING, &fw_priv->status);
 124         return sprintf(buf, "%d\n", loading);
 125 }
 126
 127 /**
 128  * firmware_loading_store - set value in the 'loading' control file
 129  * @dev: device pointer
 130  * @buf: buffer to scan for loading control value
 131  * @count: number of bytes in @buf
 132  *
 133  *      The relevant values are:
 134  *
 135  *       1: Start a load, discarding any previous partial load.
 136  *       0: Conclude the load and hand the data to the driver code.
 137  *      -1: Conclude the load with an error and discard any written data.
 138  **/
 139 static ssize_t firmware_loading_store(struct device *dev,
 140                                       struct device_attribute *attr,
 141                                       const char *buf, size_t count)
 142 {
 143         struct firmware_priv *fw_priv = dev_get_drvdata(dev);
 144         int loading = simple_strtol(buf, NULL, 10);
 145
 146         switch (loading) {
 147         case 1:
 148                 mutex_lock(&fw_lock);
 149                 if (!fw_priv->fw) {
 150                         mutex_unlock(&fw_lock);
 151                         break;
 152                 }
 153                 vfree(fw_priv->fw->data);
 154                 fw_priv->fw->data = NULL;
 155                 fw_priv->fw->size = 0;
 156                 fw_priv->alloc_size = 0;
 157                 set_bit(FW_STATUS_LOADING, &fw_priv->status);
 158                 mutex_unlock(&fw_lock);
 159                 break;
 160         case 0:
 161                 if (test_bit(FW_STATUS_LOADING, &fw_priv->status)) {
 162                         complete(&fw_priv->completion);
 163                         clear_bit(FW_STATUS_LOADING, &fw_priv->status);
 164                         break;
 165                 }
 166                 /* fallthrough */
 167         default:
 168                 printk(KERN_ERR "%s: unexpected value (%d)\n", __FUNCTION__,
 169                        loading);
 170                 /* fallthrough */
 171         case -1:
 172                 fw_load_abort(fw_priv);
 173                 break;
 174         }
 175
 176         return count;
 177 }
 178
 179 static DEVICE_ATTR(loading, 0644, firmware_loading_show, firmware_loading_store);
 180
 181 static ssize_t
 182 firmware_data_read(struct kobject *kobj,
 183                    char *buffer, loff_t offset, size_t count)
 184 {
 185         struct device *dev = to_dev(kobj);
 186         struct firmware_priv *fw_priv = dev_get_drvdata(dev);
 187         struct firmware *fw;
 188         ssize_t ret_count = count;
 189
 190         mutex_lock(&fw_lock);
 191         fw = fw_priv->fw;
 192         if (!fw || test_bit(FW_STATUS_DONE, &fw_priv->status)) {
 193                 ret_count = -ENODEV;
 194                 goto out;
 195         }
 196         if (offset > fw->size) {
 197                 ret_count = 0;
 198                 goto out;
 199         }
 200         if (offset + ret_count > fw->size)
 201                 ret_count = fw->size - offset;
 202
 203         memcpy(buffer, fw->data + offset, ret_count);
 204 out:
 205         mutex_unlock(&fw_lock);
 206         return ret_count;
 207 }
 208
 209 static int
 210 fw_realloc_buffer(struct firmware_priv *fw_priv, int min_size)
 211 {
 212         u8 *new_data;
 213         int new_size = fw_priv->alloc_size;
 214
 215         if (min_size <= fw_priv->alloc_size)
 216                 return 0;
 217
 218         new_size = ALIGN(min_size, PAGE_SIZE);
 219         new_data = vmalloc(new_size);
 220         if (!new_data) {
 221                 printk(KERN_ERR "%s: unable to alloc buffer\n", __FUNCTION__);
 222                 /* Make sure that we don't keep incomplete data */
 223                 fw_load_abort(fw_priv);
 224                 return -ENOMEM;
 225         }
 226         fw_priv->alloc_size = new_size;
 227         if (fw_priv->fw->data) {
 228                 memcpy(new_data, fw_priv->fw->data, fw_priv->fw->size);
 229                 vfree(fw_priv->fw->data);
 230         }
 231         fw_priv->fw->data = new_data;
 232         BUG_ON(min_size > fw_priv->alloc_size);
 233         return 0;
 234 }
 235
 236 /**
 237  * firmware_data_write - write method for firmware
 238  * @kobj: kobject for the device
 239  * @buffer: buffer being written
 240  * @offset: buffer offset for write in total data store area
 241  * @count: buffer size
 242  *
 243  *      Data written to the 'data' attribute will be later handed to
 244  *      the driver as a firmware image.
 245  **/
 246 static ssize_t
 247 firmware_data_write(struct kobject *kobj,
 248                     char *buffer, loff_t offset, size_t count)
 249 {
 250         struct device *dev = to_dev(kobj);
 251         struct firmware_priv *fw_priv = dev_get_drvdata(dev);
 252         struct firmware *fw;
 253         ssize_t retval;
 254
 255         if (!capable(CAP_SYS_RAWIO))
 256                 return -EPERM;
 257
 258         mutex_lock(&fw_lock);
 259         fw = fw_priv->fw;
 260         if (!fw || test_bit(FW_STATUS_DONE, &fw_priv->status)) {
 261                 retval = -ENODEV;
 262                 goto out;
 263         }
 264         retval = fw_realloc_buffer(fw_priv, offset + count);
 265         if (retval)
 266                 goto out;
 267
 268         memcpy(fw->data + offset, buffer, count);
 269
 270         fw->size = max_t(size_t, offset + count, fw->size);
 271         retval = count;
 272 out:
 273         mutex_unlock(&fw_lock);
 274         return retval;
 275 }
 276
 277 static struct bin_attribute firmware_attr_data_tmpl = {
 278         .attr = {.name = "data", .mode = 0644, .owner = THIS_MODULE},
 279         .size = 0,
 280         .read = firmware_data_read,
 281         .write = firmware_data_write,
 282 };
 283
 284 static void fw_dev_release(struct device *dev)
 285 {
 286         struct firmware_priv *fw_priv = dev_get_drvdata(dev);
 287
 288         kfree(fw_priv);
 289         kfree(dev);
 290
 291         module_put(THIS_MODULE);
 292 }
 293
 294 static void
 295 firmware_class_timeout(u_long data)
 296 {
 297         struct firmware_priv *fw_priv = (struct firmware_priv *) data;
 298         fw_load_abort(fw_priv);
 299 }
 300
 301 static inline void fw_setup_device_id(struct device *f_dev, struct device *dev)
 302 {
 303         /* XXX warning we should watch out for name collisions */
 304         strlcpy(f_dev->bus_id, dev->bus_id, BUS_ID_SIZE);
 305 }
 306
 307 static int fw_register_device(struct device **dev_p, const char *fw_name,
 308                               struct device *device)
 309 {
 310         int retval;
 311         struct firmware_priv *fw_priv = kzalloc(sizeof(*fw_priv),
 312                                                 GFP_KERNEL);
 313         struct device *f_dev = kzalloc(sizeof(*f_dev), GFP_KERNEL);
 314
 315         *dev_p = NULL;
 316
 317         if (!fw_priv || !f_dev) {
 318                 printk(KERN_ERR "%s: kmalloc failed\n", __FUNCTION__);
 319                 retval = -ENOMEM;
 320                 goto error_kfree;
 321         }
 322
 323         init_completion(&fw_priv->completion);
 324         fw_priv->attr_data = firmware_attr_data_tmpl;
 325         strlcpy(fw_priv->fw_id, fw_name, FIRMWARE_NAME_MAX);
 326
 327         fw_priv->timeout.function = firmware_class_timeout;
 328         fw_priv->timeout.data = (u_long) fw_priv;
 329         init_timer(&fw_priv->timeout);
 330
 331         fw_setup_device_id(f_dev, device);
 332         f_dev->parent = device;
 333         f_dev->class = &firmware_class;
 334         dev_set_drvdata(f_dev, fw_priv);
 335         retval = device_register(f_dev);
 336         if (retval) {
 337                 printk(KERN_ERR "%s: device_register failed\n",
 338                        __FUNCTION__);
 339                 goto error_kfree;
 340         }
 341         *dev_p = f_dev;
 342         return 0;
 343
 344 error_kfree:
 345         kfree(fw_priv);
 346         kfree(f_dev);
 347         return retval;
 348 }
 349
 350 static int fw_setup_device(struct firmware *fw, struct device **dev_p,
 351                            const char *fw_name, struct device *device,
 352                            int uevent)
 353 {
 354         struct device *f_dev;
 355         struct firmware_priv *fw_priv;
 356         int retval;
 357
 358         *dev_p = NULL;
 359         retval = fw_register_device(&f_dev, fw_name, device);
 360         if (retval)
 361                 goto out;
 362
 363         /* Need to pin this module until class device is destroyed */
 364         __module_get(THIS_MODULE);
 365
 366         fw_priv = dev_get_drvdata(f_dev);
 367
 368         fw_priv->fw = fw;
 369         retval = sysfs_create_bin_file(&f_dev->kobj, &fw_priv->attr_data);
 370         if (retval) {
 371                 printk(KERN_ERR "%s: sysfs_create_bin_file failed\n",
 372                        __FUNCTION__);
 373                 goto error_unreg;
 374         }
 375
 376         retval = device_create_file(f_dev, &dev_attr_loading);
 377         if (retval) {
 378                 printk(KERN_ERR "%s: device_create_file failed\n",
 379                        __FUNCTION__);
 380                 goto error_unreg;
 381         }
 382
 383         if (uevent)
 384                 set_bit(FW_STATUS_READY, &fw_priv->status);
 385         else
 386                 set_bit(FW_STATUS_READY_NOHOTPLUG, &fw_priv->status);
 387         *dev_p = f_dev;
 388         goto out;
 389
 390 error_unreg:
 391         device_unregister(f_dev);
 392 out:
 393         return retval;
 394 }
 395
 396 static int
 397 _request_firmware(const struct firmware **firmware_p, const char *name,
 398                  struct device *device, int uevent)
 399 {
 400         struct device *f_dev;
 401         struct firmware_priv *fw_priv;
 402         struct firmware *firmware;
 403         int retval;
 404
 405         if (!firmware_p)
 406                 return -EINVAL;
 407
 408         *firmware_p = firmware = kzalloc(sizeof(*firmware), GFP_KERNEL);
 409         if (!firmware) {
 410                 printk(KERN_ERR "%s: kmalloc(struct firmware) failed\n",
 411                        __FUNCTION__);
 412                 retval = -ENOMEM;
 413                 goto out;
 414         }
 415
 416         retval = fw_setup_device(firmware, &f_dev, name, device, uevent);
 417         if (retval)
 418                 goto error_kfree_fw;
 419
 420         fw_priv = dev_get_drvdata(f_dev);
 421
 422         if (uevent) {
 423                 if (loading_timeout > 0) {
 424                         fw_priv->timeout.expires = jiffies + loading_timeout * HZ;
 425                         add_timer(&fw_priv->timeout);
 426                 }
 427
 428                 kobject_uevent(&f_dev->kobj, KOBJ_ADD);
 429                 wait_for_completion(&fw_priv->completion);
 430                 set_bit(FW_STATUS_DONE, &fw_priv->status);
 431                 del_timer_sync(&fw_priv->timeout);
 432         } else
 433                 wait_for_completion(&fw_priv->completion);
 434
 435         mutex_lock(&fw_lock);
 436         if (!fw_priv->fw->size || test_bit(FW_STATUS_ABORT, &fw_priv->status)) {
 437                 retval = -ENOENT;
 438                 release_firmware(fw_priv->fw);
 439                 *firmware_p = NULL;
 440         }
 441         fw_priv->fw = NULL;
 442         mutex_unlock(&fw_lock);
 443         device_unregister(f_dev);
 444         goto out;
 445
 446 error_kfree_fw:
 447         kfree(firmware);
 448         *firmware_p = NULL;
 449 out:
 450         return retval;
 451 }
 452
 453 /**
 454  * request_firmware: - send firmware request and wait for it
 455  * @firmware_p: pointer to firmware image
 456  * @name: name of firmware file
 457  * @device: device for which firmware is being loaded
 458  *
 459  *      @firmware_p will be used to return a firmware image by the name
 460  *      of @name for device @device.
 461  *
 462  *      Should be called from user context where sleeping is allowed.
 463  *
 464  *      @name will be used as $FIRMWARE in the uevent environment and
 465  *      should be distinctive enough not to be confused with any other
 466  *      firmware image for this or any other device.
 467  **/
 468 int
 469 request_firmware(const struct firmware **firmware_p, const char *name,
 470                  struct device *device)
 471 {
 472         int uevent = 1;
 473         return _request_firmware(firmware_p, name, device, uevent);
 474 }
 475
 476 /**
 477  * release_firmware: - release the resource associated with a firmware image
 478  * @fw: firmware resource to release
 479  **/
 480 void
 481 release_firmware(const struct firmware *fw)
 482 {
 483         if (fw) {
 484                 vfree(fw->data);
 485                 kfree(fw);
 486         }
 487 }
 488
 489 /* Async support */
 490 struct firmware_work {
 491         struct work_struct work;
 492         struct module *module;
 493         const char *name;
 494         struct device *device;
 495         void *context;
 496         void (*cont)(const struct firmware *fw, void *context);
 497         int uevent;
 498 };
 499
 500 static int
 501 request_firmware_work_func(void *arg)
 502 {
 503         struct firmware_work *fw_work = arg;
 504         const struct firmware *fw;
 505         int ret;
 506         if (!arg) {
 507                 WARN_ON(1);
 508                 return 0;
 509         }
 510         ret = _request_firmware(&fw, fw_work->name, fw_work->device,
 511                 fw_work->uevent);
 512         if (ret < 0)
 513                 fw_work->cont(NULL, fw_work->context);
 514         else {
 515                 fw_work->cont(fw, fw_work->context);
 516                 release_firmware(fw);
 517         }
 518         module_put(fw_work->module);
 519         kfree(fw_work);
 520         return ret;
 521 }
 522
 523 /**
 524  * request_firmware_nowait: asynchronous version of request_firmware
 525  * @module: module requesting the firmware
 526  * @uevent: sends uevent to copy the firmware image if this flag
 527  *      is non-zero else the firmware copy must be done manually.
 528  * @name: name of firmware file
 529  * @device: device for which firmware is being loaded
 530  * @context: will be passed over to @cont, and
 531  *      @fw may be %NULL if firmware request fails.
 532  * @cont: function will be called asynchronously when the firmware
 533  *      request is over.
 534  *
 535  *      Asynchronous variant of request_firmware() for contexts where
 536  *      it is not possible to sleep.
 537  **/
 538 int
 539 request_firmware_nowait(
 540         struct module *module, int uevent,
 541         const char *name, struct device *device, void *context,
 542         void (*cont)(const struct firmware *fw, void *context))
 543 {
 544         struct task_struct *task;
 545         struct firmware_work *fw_work = kmalloc(sizeof (struct firmware_work),
 546                                                 GFP_ATOMIC);
 547
 548         if (!fw_work)
 549                 return -ENOMEM;
 550         if (!try_module_get(module)) {
 551                 kfree(fw_work);
 552                 return -EFAULT;
 553         }
 554
 555         *fw_work = (struct firmware_work) {
 556                 .module = module,
 557                 .name = name,
 558                 .device = device,
 559                 .context = context,
 560                 .cont = cont,
 561                 .uevent = uevent,
 562         };
 563
 564         task = kthread_run(request_firmware_work_func, fw_work,
 565                             "firmware/%s", name);
 566
 567         if (IS_ERR(task)) {
 568                 fw_work->cont(NULL, fw_work->context);
 569                 module_put(fw_work->module);
 570                 kfree(fw_work);
 571                 return PTR_ERR(task);
 572         }
 573         return 0;
 574 }
 575
 576 static int __init
 577 firmware_class_init(void)
 578 {
 579         int error;
 580         error = class_register(&firmware_class);
 581         if (error) {
 582                 printk(KERN_ERR "%s: class_register failed\n", __FUNCTION__);
 583                 return error;
 584         }
 585         error = class_create_file(&firmware_class, &class_attr_timeout);
 586         if (error) {
 587                 printk(KERN_ERR "%s: class_create_file failed\n",
 588                        __FUNCTION__);
 589                 class_unregister(&firmware_class);
 590         }
 591         return error;
 592
 593 }
 594 static void __exit
 595 firmware_class_exit(void)
 596 {
 597         class_unregister(&firmware_class);
 598 }
 599
 600 fs_initcall(firmware_class_init);
 601 module_exit(firmware_class_exit);
 602
 603 EXPORT_SYMBOL(release_firmware);
 604 EXPORT_SYMBOL(request_firmware);
 605 EXPORT_SYMBOL(request_firmware_nowait);