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 = 60;        /* 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         else if (loading_timeout < 60) {
  87                 if (printk_ratelimit())
  88                         printk(KERN_INFO
  89                                "firmware_class: attempt to set timeout to %d\n",
  90                                loading_timeout);
  91                 loading_timeout = 60;
  92         }
  93         return count;
  94 }
  95
  96 static CLASS_ATTR(timeout, 0644, firmware_timeout_show, firmware_timeout_store);
  97
  98 static void fw_dev_release(struct device *dev);
  99
 100 static int firmware_uevent(struct device *dev, char **envp, int num_envp,
 101                            char *buffer, int buffer_size)
 102 {
 103         struct firmware_priv *fw_priv = dev_get_drvdata(dev);
 104         int i = 0, len = 0;
 105
 106         if (!test_bit(FW_STATUS_READY, &fw_priv->status))
 107                 return -ENODEV;
 108
 109         if (add_uevent_var(envp, num_envp, &i, buffer, buffer_size, &len,
 110                            "FIRMWARE=%s", fw_priv->fw_id))
 111                 return -ENOMEM;
 112         if (add_uevent_var(envp, num_envp, &i, buffer, buffer_size, &len,
 113                            "TIMEOUT=%i", loading_timeout))
 114                 return -ENOMEM;
 115         envp[i] = NULL;
 116
 117         return 0;
 118 }
 119
 120 static struct class firmware_class = {
 121         .name           = "firmware",
 122         .dev_uevent     = firmware_uevent,
 123         .dev_release    = fw_dev_release,
 124 };
 125
 126 static ssize_t firmware_loading_show(struct device *dev,
 127                                      struct device_attribute *attr, char *buf)
 128 {
 129         struct firmware_priv *fw_priv = dev_get_drvdata(dev);
 130         int loading = test_bit(FW_STATUS_LOADING, &fw_priv->status);
 131         return sprintf(buf, "%d\n", loading);
 132 }
 133
 134 /**
 135  * firmware_loading_store - set value in the 'loading' control file
 136  * @dev: device pointer
 137  * @attr: device attribute pointer
 138  * @buf: buffer to scan for loading control value
 139  * @count: number of bytes in @buf
 140  *
 141  *      The relevant values are:
 142  *
 143  *       1: Start a load, discarding any previous partial load.
 144  *       0: Conclude the load and hand the data to the driver code.
 145  *      -1: Conclude the load with an error and discard any written data.
 146  **/
 147 static ssize_t firmware_loading_store(struct device *dev,
 148                                       struct device_attribute *attr,
 149                                       const char *buf, size_t count)
 150 {
 151         struct firmware_priv *fw_priv = dev_get_drvdata(dev);
 152         int loading = simple_strtol(buf, NULL, 10);
 153
 154         switch (loading) {
 155         case 1:
 156                 mutex_lock(&fw_lock);
 157                 if (!fw_priv->fw) {
 158                         mutex_unlock(&fw_lock);
 159                         break;
 160                 }
 161                 vfree(fw_priv->fw->data);
 162                 fw_priv->fw->data = NULL;
 163                 fw_priv->fw->size = 0;
 164                 fw_priv->alloc_size = 0;
 165                 set_bit(FW_STATUS_LOADING, &fw_priv->status);
 166                 mutex_unlock(&fw_lock);
 167                 break;
 168         case 0:
 169                 if (test_bit(FW_STATUS_LOADING, &fw_priv->status)) {
 170                         complete(&fw_priv->completion);
 171                         clear_bit(FW_STATUS_LOADING, &fw_priv->status);
 172                         break;
 173                 }
 174                 /* fallthrough */
 175         default:
 176                 printk(KERN_ERR "%s: unexpected value (%d)\n", __FUNCTION__,
 177                        loading);
 178                 /* fallthrough */
 179         case -1:
 180                 fw_load_abort(fw_priv);
 181                 break;
 182         }
 183
 184         return count;
 185 }
 186
 187 static DEVICE_ATTR(loading, 0644, firmware_loading_show, firmware_loading_store);
 188
 189 static ssize_t
 190 firmware_data_read(struct kobject *kobj,
 191                    char *buffer, loff_t offset, size_t count)
 192 {
 193         struct device *dev = to_dev(kobj);
 194         struct firmware_priv *fw_priv = dev_get_drvdata(dev);
 195         struct firmware *fw;
 196         ssize_t ret_count = count;
 197
 198         mutex_lock(&fw_lock);
 199         fw = fw_priv->fw;
 200         if (!fw || test_bit(FW_STATUS_DONE, &fw_priv->status)) {
 201                 ret_count = -ENODEV;
 202                 goto out;
 203         }
 204         if (offset > fw->size) {
 205                 ret_count = 0;
 206                 goto out;
 207         }
 208         if (offset + ret_count > fw->size)
 209                 ret_count = fw->size - offset;
 210
 211         memcpy(buffer, fw->data + offset, ret_count);
 212 out:
 213         mutex_unlock(&fw_lock);
 214         return ret_count;
 215 }
 216
 217 static int
 218 fw_realloc_buffer(struct firmware_priv *fw_priv, int min_size)
 219 {
 220         u8 *new_data;
 221         int new_size = fw_priv->alloc_size;
 222
 223         if (min_size <= fw_priv->alloc_size)
 224                 return 0;
 225
 226         new_size = ALIGN(min_size, PAGE_SIZE);
 227         new_data = vmalloc(new_size);
 228         if (!new_data) {
 229                 printk(KERN_ERR "%s: unable to alloc buffer\n", __FUNCTION__);
 230                 /* Make sure that we don't keep incomplete data */
 231                 fw_load_abort(fw_priv);
 232                 return -ENOMEM;
 233         }
 234         fw_priv->alloc_size = new_size;
 235         if (fw_priv->fw->data) {
 236                 memcpy(new_data, fw_priv->fw->data, fw_priv->fw->size);
 237                 vfree(fw_priv->fw->data);
 238         }
 239         fw_priv->fw->data = new_data;
 240         BUG_ON(min_size > fw_priv->alloc_size);
 241         return 0;
 242 }
 243
 244 /**
 245  * firmware_data_write - write method for firmware
 246  * @kobj: kobject for the device
 247  * @buffer: buffer being written
 248  * @offset: buffer offset for write in total data store area
 249  * @count: buffer size
 250  *
 251  *      Data written to the 'data' attribute will be later handed to
 252  *      the driver as a firmware image.
 253  **/
 254 static ssize_t
 255 firmware_data_write(struct kobject *kobj,
 256                     char *buffer, loff_t offset, size_t count)
 257 {
 258         struct device *dev = to_dev(kobj);
 259         struct firmware_priv *fw_priv = dev_get_drvdata(dev);
 260         struct firmware *fw;
 261         ssize_t retval;
 262
 263         if (!capable(CAP_SYS_RAWIO))
 264                 return -EPERM;
 265
 266         mutex_lock(&fw_lock);
 267         fw = fw_priv->fw;
 268         if (!fw || test_bit(FW_STATUS_DONE, &fw_priv->status)) {
 269                 retval = -ENODEV;
 270                 goto out;
 271         }
 272         retval = fw_realloc_buffer(fw_priv, offset + count);
 273         if (retval)
 274                 goto out;
 275
 276         memcpy(fw->data + offset, buffer, count);
 277
 278         fw->size = max_t(size_t, offset + count, fw->size);
 279         retval = count;
 280 out:
 281         mutex_unlock(&fw_lock);
 282         return retval;
 283 }
 284
 285 static struct bin_attribute firmware_attr_data_tmpl = {
 286         .attr = {.name = "data", .mode = 0644, .owner = THIS_MODULE},
 287         .size = 0,
 288         .read = firmware_data_read,
 289         .write = firmware_data_write,
 290 };
 291
 292 static void fw_dev_release(struct device *dev)
 293 {
 294         struct firmware_priv *fw_priv = dev_get_drvdata(dev);
 295
 296         kfree(fw_priv);
 297         kfree(dev);
 298
 299         module_put(THIS_MODULE);
 300 }
 301
 302 static void
 303 firmware_class_timeout(u_long data)
 304 {
 305         struct firmware_priv *fw_priv = (struct firmware_priv *) data;
 306         fw_load_abort(fw_priv);
 307 }
 308
 309 static inline void fw_setup_device_id(struct device *f_dev, struct device *dev)
 310 {
 311         /* XXX warning we should watch out for name collisions */
 312         strlcpy(f_dev->bus_id, dev->bus_id, BUS_ID_SIZE);
 313 }
 314
 315 static int fw_register_device(struct device **dev_p, const char *fw_name,
 316                               struct device *device)
 317 {
 318         int retval;
 319         struct firmware_priv *fw_priv = kzalloc(sizeof(*fw_priv),
 320                                                 GFP_KERNEL);
 321         struct device *f_dev = kzalloc(sizeof(*f_dev), GFP_KERNEL);
 322
 323         *dev_p = NULL;
 324
 325         if (!fw_priv || !f_dev) {
 326                 printk(KERN_ERR "%s: kmalloc failed\n", __FUNCTION__);
 327                 retval = -ENOMEM;
 328                 goto error_kfree;
 329         }
 330
 331         init_completion(&fw_priv->completion);
 332         fw_priv->attr_data = firmware_attr_data_tmpl;
 333         strlcpy(fw_priv->fw_id, fw_name, FIRMWARE_NAME_MAX);
 334
 335         fw_priv->timeout.function = firmware_class_timeout;
 336         fw_priv->timeout.data = (u_long) fw_priv;
 337         init_timer(&fw_priv->timeout);
 338
 339         fw_setup_device_id(f_dev, device);
 340         f_dev->parent = device;
 341         f_dev->class = &firmware_class;
 342         dev_set_drvdata(f_dev, fw_priv);
 343         retval = device_register(f_dev);
 344         if (retval) {
 345                 printk(KERN_ERR "%s: device_register failed\n",
 346                        __FUNCTION__);
 347                 goto error_kfree;
 348         }
 349         *dev_p = f_dev;
 350         return 0;
 351
 352 error_kfree:
 353         kfree(fw_priv);
 354         kfree(f_dev);
 355         return retval;
 356 }
 357
 358 static int fw_setup_device(struct firmware *fw, struct device **dev_p,
 359                            const char *fw_name, struct device *device,
 360                            int uevent)
 361 {
 362         struct device *f_dev;
 363         struct firmware_priv *fw_priv;
 364         int retval;
 365
 366         *dev_p = NULL;
 367         retval = fw_register_device(&f_dev, fw_name, device);
 368         if (retval)
 369                 goto out;
 370
 371         /* Need to pin this module until class device is destroyed */
 372         __module_get(THIS_MODULE);
 373
 374         fw_priv = dev_get_drvdata(f_dev);
 375
 376         fw_priv->fw = fw;
 377         retval = sysfs_create_bin_file(&f_dev->kobj, &fw_priv->attr_data);
 378         if (retval) {
 379                 printk(KERN_ERR "%s: sysfs_create_bin_file failed\n",
 380                        __FUNCTION__);
 381                 goto error_unreg;
 382         }
 383
 384         retval = device_create_file(f_dev, &dev_attr_loading);
 385         if (retval) {
 386                 printk(KERN_ERR "%s: device_create_file failed\n",
 387                        __FUNCTION__);
 388                 goto error_unreg;
 389         }
 390
 391         if (uevent)
 392                 set_bit(FW_STATUS_READY, &fw_priv->status);
 393         else
 394                 set_bit(FW_STATUS_READY_NOHOTPLUG, &fw_priv->status);
 395         *dev_p = f_dev;
 396         goto out;
 397
 398 error_unreg:
 399         device_unregister(f_dev);
 400 out:
 401         return retval;
 402 }
 403
 404 static int
 405 _request_firmware(const struct firmware **firmware_p, const char *name,
 406                  struct device *device, int uevent)
 407 {
 408         struct device *f_dev;
 409         struct firmware_priv *fw_priv;
 410         struct firmware *firmware;
 411         int retval;
 412
 413         if (!firmware_p)
 414                 return -EINVAL;
 415
 416         *firmware_p = firmware = kzalloc(sizeof(*firmware), GFP_KERNEL);
 417         if (!firmware) {
 418                 printk(KERN_ERR "%s: kmalloc(struct firmware) failed\n",
 419                        __FUNCTION__);
 420                 retval = -ENOMEM;
 421                 goto out;
 422         }
 423
 424         retval = fw_setup_device(firmware, &f_dev, name, device, uevent);
 425         if (retval)
 426                 goto error_kfree_fw;
 427
 428         fw_priv = dev_get_drvdata(f_dev);
 429
 430         if (uevent) {
 431                 if (loading_timeout > 0) {
 432                         fw_priv->timeout.expires = jiffies + loading_timeout * HZ;
 433                         add_timer(&fw_priv->timeout);
 434                 }
 435
 436                 kobject_uevent(&f_dev->kobj, KOBJ_ADD);
 437                 wait_for_completion(&fw_priv->completion);
 438                 set_bit(FW_STATUS_DONE, &fw_priv->status);
 439                 del_timer_sync(&fw_priv->timeout);
 440         } else
 441                 wait_for_completion(&fw_priv->completion);
 442
 443         mutex_lock(&fw_lock);
 444         if (!fw_priv->fw->size || test_bit(FW_STATUS_ABORT, &fw_priv->status)) {
 445                 retval = -ENOENT;
 446                 release_firmware(fw_priv->fw);
 447                 *firmware_p = NULL;
 448         }
 449         fw_priv->fw = NULL;
 450         mutex_unlock(&fw_lock);
 451         device_unregister(f_dev);
 452         goto out;
 453
 454 error_kfree_fw:
 455         kfree(firmware);
 456         *firmware_p = NULL;
 457 out:
 458         return retval;
 459 }
 460
 461 /**
 462  * request_firmware: - send firmware request and wait for it
 463  * @firmware_p: pointer to firmware image
 464  * @name: name of firmware file
 465  * @device: device for which firmware is being loaded
 466  *
 467  *      @firmware_p will be used to return a firmware image by the name
 468  *      of @name for device @device.
 469  *
 470  *      Should be called from user context where sleeping is allowed.
 471  *
 472  *      @name will be used as $FIRMWARE in the uevent environment and
 473  *      should be distinctive enough not to be confused with any other
 474  *      firmware image for this or any other device.
 475  **/
 476 int
 477 request_firmware(const struct firmware **firmware_p, const char *name,
 478                  struct device *device)
 479 {
 480         int uevent = 1;
 481         return _request_firmware(firmware_p, name, device, uevent);
 482 }
 483
 484 /**
 485  * release_firmware: - release the resource associated with a firmware image
 486  * @fw: firmware resource to release
 487  **/
 488 void
 489 release_firmware(const struct firmware *fw)
 490 {
 491         if (fw) {
 492                 vfree(fw->data);
 493                 kfree(fw);
 494         }
 495 }
 496
 497 /* Async support */
 498 struct firmware_work {
 499         struct work_struct work;
 500         struct module *module;
 501         const char *name;
 502         struct device *device;
 503         void *context;
 504         void (*cont)(const struct firmware *fw, void *context);
 505         int uevent;
 506 };
 507
 508 static int
 509 request_firmware_work_func(void *arg)
 510 {
 511         struct firmware_work *fw_work = arg;
 512         const struct firmware *fw;
 513         int ret;
 514         if (!arg) {
 515                 WARN_ON(1);
 516                 return 0;
 517         }
 518         ret = _request_firmware(&fw, fw_work->name, fw_work->device,
 519                 fw_work->uevent);
 520         if (ret < 0)
 521                 fw_work->cont(NULL, fw_work->context);
 522         else {
 523                 fw_work->cont(fw, fw_work->context);
 524                 release_firmware(fw);
 525         }
 526         module_put(fw_work->module);
 527         kfree(fw_work);
 528         return ret;
 529 }
 530
 531 /**
 532  * request_firmware_nowait: asynchronous version of request_firmware
 533  * @module: module requesting the firmware
 534  * @uevent: sends uevent to copy the firmware image if this flag
 535  *      is non-zero else the firmware copy must be done manually.
 536  * @name: name of firmware file
 537  * @device: device for which firmware is being loaded
 538  * @context: will be passed over to @cont, and
 539  *      @fw may be %NULL if firmware request fails.
 540  * @cont: function will be called asynchronously when the firmware
 541  *      request is over.
 542  *
 543  *      Asynchronous variant of request_firmware() for contexts where
 544  *      it is not possible to sleep.
 545  **/
 546 int
 547 request_firmware_nowait(
 548         struct module *module, int uevent,
 549         const char *name, struct device *device, void *context,
 550         void (*cont)(const struct firmware *fw, void *context))
 551 {
 552         struct task_struct *task;
 553         struct firmware_work *fw_work = kmalloc(sizeof (struct firmware_work),
 554                                                 GFP_ATOMIC);
 555
 556         if (!fw_work)
 557                 return -ENOMEM;
 558         if (!try_module_get(module)) {
 559                 kfree(fw_work);
 560                 return -EFAULT;
 561         }
 562
 563         *fw_work = (struct firmware_work) {
 564                 .module = module,
 565                 .name = name,
 566                 .device = device,
 567                 .context = context,
 568                 .cont = cont,
 569                 .uevent = uevent,
 570         };
 571
 572         task = kthread_run(request_firmware_work_func, fw_work,
 573                             "firmware/%s", name);
 574
 575         if (IS_ERR(task)) {
 576                 fw_work->cont(NULL, fw_work->context);
 577                 module_put(fw_work->module);
 578                 kfree(fw_work);
 579                 return PTR_ERR(task);
 580         }
 581         return 0;
 582 }
 583
 584 static int __init
 585 firmware_class_init(void)
 586 {
 587         int error;
 588         error = class_register(&firmware_class);
 589         if (error) {
 590                 printk(KERN_ERR "%s: class_register failed\n", __FUNCTION__);
 591                 return error;
 592         }
 593         error = class_create_file(&firmware_class, &class_attr_timeout);
 594         if (error) {
 595                 printk(KERN_ERR "%s: class_create_file failed\n",
 596                        __FUNCTION__);
 597                 class_unregister(&firmware_class);
 598         }
 599         return error;
 600
 601 }
 602 static void __exit
 603 firmware_class_exit(void)
 604 {
 605         class_unregister(&firmware_class);
 606 }
 607
 608 fs_initcall(firmware_class_init);
 609 module_exit(firmware_class_exit);
 610
 611 EXPORT_SYMBOL(release_firmware);
 612 EXPORT_SYMBOL(request_firmware);
 613 EXPORT_SYMBOL(request_firmware_nowait);