linux/drivers/base/firmware_class.c
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   1/*
   2 * firmware_class.c - Multi purpose firmware loading support
   3 *
   4 * Copyright (c) 2003 Manuel Estrada Sainz
   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
  26MODULE_AUTHOR("Manuel Estrada Sainz");
  27MODULE_DESCRIPTION("Multi purpose firmware loading support");
  28MODULE_LICENSE("GPL");
  29
  30enum {
  31        FW_STATUS_LOADING,
  32        FW_STATUS_DONE,
  33        FW_STATUS_ABORT,
  34};
  35
  36static int loading_timeout = 60;        /* In seconds */
  37
  38/* fw_lock could be moved to 'struct firmware_priv' but since it is just
  39 * guarding for corner cases a global lock should be OK */
  40static DEFINE_MUTEX(fw_lock);
  41
  42struct firmware_priv {
  43        char fw_id[FIRMWARE_NAME_MAX];
  44        struct completion completion;
  45        struct bin_attribute attr_data;
  46        struct firmware *fw;
  47        unsigned long status;
  48        int alloc_size;
  49        struct timer_list timeout;
  50};
  51
  52#ifdef CONFIG_FW_LOADER
  53extern struct builtin_fw __start_builtin_fw[];
  54extern struct builtin_fw __end_builtin_fw[];
  55#else /* Module case. Avoid ifdefs later; it'll all optimise out */
  56static struct builtin_fw *__start_builtin_fw;
  57static struct builtin_fw *__end_builtin_fw;
  58#endif
  59
  60static void
  61fw_load_abort(struct firmware_priv *fw_priv)
  62{
  63        set_bit(FW_STATUS_ABORT, &fw_priv->status);
  64        wmb();
  65        complete(&fw_priv->completion);
  66}
  67
  68static ssize_t
  69firmware_timeout_show(struct class *class, char *buf)
  70{
  71        return sprintf(buf, "%d\n", loading_timeout);
  72}
  73
  74/**
  75 * firmware_timeout_store - set number of seconds to wait for firmware
  76 * @class: device class pointer
  77 * @buf: buffer to scan for timeout value
  78 * @count: number of bytes in @buf
  79 *
  80 *      Sets the number of seconds to wait for the firmware.  Once
  81 *      this expires an error will be returned to the driver and no
  82 *      firmware will be provided.
  83 *
  84 *      Note: zero means 'wait forever'.
  85 **/
  86static ssize_t
  87firmware_timeout_store(struct class *class, const char *buf, size_t count)
  88{
  89        loading_timeout = simple_strtol(buf, NULL, 10);
  90        if (loading_timeout < 0)
  91                loading_timeout = 0;
  92        return count;
  93}
  94
  95static CLASS_ATTR(timeout, 0644, firmware_timeout_show, firmware_timeout_store);
  96
  97static void fw_dev_release(struct device *dev);
  98
  99static int firmware_uevent(struct device *dev, struct kobj_uevent_env *env)
 100{
 101        struct firmware_priv *fw_priv = dev_get_drvdata(dev);
 102
 103        if (add_uevent_var(env, "FIRMWARE=%s", fw_priv->fw_id))
 104                return -ENOMEM;
 105        if (add_uevent_var(env, "TIMEOUT=%i", loading_timeout))
 106                return -ENOMEM;
 107
 108        return 0;
 109}
 110
 111static struct class firmware_class = {
 112        .name           = "firmware",
 113        .dev_uevent     = firmware_uevent,
 114        .dev_release    = fw_dev_release,
 115};
 116
 117static ssize_t firmware_loading_show(struct device *dev,
 118                                     struct device_attribute *attr, char *buf)
 119{
 120        struct firmware_priv *fw_priv = dev_get_drvdata(dev);
 121        int loading = test_bit(FW_STATUS_LOADING, &fw_priv->status);
 122        return sprintf(buf, "%d\n", loading);
 123}
 124
 125/**
 126 * firmware_loading_store - set value in the 'loading' control file
 127 * @dev: device pointer
 128 * @attr: device attribute pointer
 129 * @buf: buffer to scan for loading control value
 130 * @count: number of bytes in @buf
 131 *
 132 *      The relevant values are:
 133 *
 134 *       1: Start a load, discarding any previous partial load.
 135 *       0: Conclude the load and hand the data to the driver code.
 136 *      -1: Conclude the load with an error and discard any written data.
 137 **/
 138static ssize_t firmware_loading_store(struct device *dev,
 139                                      struct device_attribute *attr,
 140                                      const char *buf, size_t count)
 141{
 142        struct firmware_priv *fw_priv = dev_get_drvdata(dev);
 143        int loading = simple_strtol(buf, NULL, 10);
 144
 145        switch (loading) {
 146        case 1:
 147                mutex_lock(&fw_lock);
 148                if (!fw_priv->fw) {
 149                        mutex_unlock(&fw_lock);
 150                        break;
 151                }
 152                vfree(fw_priv->fw->data);
 153                fw_priv->fw->data = NULL;
 154                fw_priv->fw->size = 0;
 155                fw_priv->alloc_size = 0;
 156                set_bit(FW_STATUS_LOADING, &fw_priv->status);
 157                mutex_unlock(&fw_lock);
 158                break;
 159        case 0:
 160                if (test_bit(FW_STATUS_LOADING, &fw_priv->status)) {
 161                        complete(&fw_priv->completion);
 162                        clear_bit(FW_STATUS_LOADING, &fw_priv->status);
 163                        break;
 164                }
 165                /* fallthrough */
 166        default:
 167                dev_err(dev, "%s: unexpected value (%d)\n", __func__, loading);
 168                /* fallthrough */
 169        case -1:
 170                fw_load_abort(fw_priv);
 171                break;
 172        }
 173
 174        return count;
 175}
 176
 177static DEVICE_ATTR(loading, 0644, firmware_loading_show, firmware_loading_store);
 178
 179static ssize_t
 180firmware_data_read(struct kobject *kobj, struct bin_attribute *bin_attr,
 181                   char *buffer, loff_t offset, size_t count)
 182{
 183        struct device *dev = to_dev(kobj);
 184        struct firmware_priv *fw_priv = dev_get_drvdata(dev);
 185        struct firmware *fw;
 186        ssize_t ret_count;
 187
 188        mutex_lock(&fw_lock);
 189        fw = fw_priv->fw;
 190        if (!fw || test_bit(FW_STATUS_DONE, &fw_priv->status)) {
 191                ret_count = -ENODEV;
 192                goto out;
 193        }
 194        ret_count = memory_read_from_buffer(buffer, count, &offset,
 195                                                fw->data, fw->size);
 196out:
 197        mutex_unlock(&fw_lock);
 198        return ret_count;
 199}
 200
 201static int
 202fw_realloc_buffer(struct firmware_priv *fw_priv, int min_size)
 203{
 204        u8 *new_data;
 205        int new_size = fw_priv->alloc_size;
 206
 207        if (min_size <= fw_priv->alloc_size)
 208                return 0;
 209
 210        new_size = ALIGN(min_size, PAGE_SIZE);
 211        new_data = vmalloc(new_size);
 212        if (!new_data) {
 213                printk(KERN_ERR "%s: unable to alloc buffer\n", __func__);
 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 = new_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 - write method for firmware
 230 * @kobj: kobject for the device
 231 * @bin_attr: bin_attr structure
 232 * @buffer: buffer being written
 233 * @offset: buffer offset for write in total data store area
 234 * @count: buffer size
 235 *
 236 *      Data written to the 'data' attribute will be later handed to
 237 *      the driver as a firmware image.
 238 **/
 239static ssize_t
 240firmware_data_write(struct kobject *kobj, struct bin_attribute *bin_attr,
 241                    char *buffer, loff_t offset, size_t count)
 242{
 243        struct device *dev = to_dev(kobj);
 244        struct firmware_priv *fw_priv = dev_get_drvdata(dev);
 245        struct firmware *fw;
 246        ssize_t retval;
 247
 248        if (!capable(CAP_SYS_RAWIO))
 249                return -EPERM;
 250
 251        mutex_lock(&fw_lock);
 252        fw = fw_priv->fw;
 253        if (!fw || test_bit(FW_STATUS_DONE, &fw_priv->status)) {
 254                retval = -ENODEV;
 255                goto out;
 256        }
 257        retval = fw_realloc_buffer(fw_priv, offset + count);
 258        if (retval)
 259                goto out;
 260
 261        memcpy((u8 *)fw->data + offset, buffer, count);
 262
 263        fw->size = max_t(size_t, offset + count, fw->size);
 264        retval = count;
 265out:
 266        mutex_unlock(&fw_lock);
 267        return retval;
 268}
 269
 270static struct bin_attribute firmware_attr_data_tmpl = {
 271        .attr = {.name = "data", .mode = 0644},
 272        .size = 0,
 273        .read = firmware_data_read,
 274        .write = firmware_data_write,
 275};
 276
 277static void fw_dev_release(struct device *dev)
 278{
 279        struct firmware_priv *fw_priv = dev_get_drvdata(dev);
 280
 281        kfree(fw_priv);
 282        kfree(dev);
 283
 284        module_put(THIS_MODULE);
 285}
 286
 287static void
 288firmware_class_timeout(u_long data)
 289{
 290        struct firmware_priv *fw_priv = (struct firmware_priv *) data;
 291        fw_load_abort(fw_priv);
 292}
 293
 294static inline void fw_setup_device_id(struct device *f_dev, struct device *dev)
 295{
 296        /* XXX warning we should watch out for name collisions */
 297        strlcpy(f_dev->bus_id, dev->bus_id, BUS_ID_SIZE);
 298}
 299
 300static int fw_register_device(struct device **dev_p, const char *fw_name,
 301                              struct device *device)
 302{
 303        int retval;
 304        struct firmware_priv *fw_priv = kzalloc(sizeof(*fw_priv),
 305                                                GFP_KERNEL);
 306        struct device *f_dev = kzalloc(sizeof(*f_dev), GFP_KERNEL);
 307
 308        *dev_p = NULL;
 309
 310        if (!fw_priv || !f_dev) {
 311                dev_err(device, "%s: kmalloc failed\n", __func__);
 312                retval = -ENOMEM;
 313                goto error_kfree;
 314        }
 315
 316        init_completion(&fw_priv->completion);
 317        fw_priv->attr_data = firmware_attr_data_tmpl;
 318        strlcpy(fw_priv->fw_id, fw_name, FIRMWARE_NAME_MAX);
 319
 320        fw_priv->timeout.function = firmware_class_timeout;
 321        fw_priv->timeout.data = (u_long) fw_priv;
 322        init_timer(&fw_priv->timeout);
 323
 324        fw_setup_device_id(f_dev, device);
 325        f_dev->parent = device;
 326        f_dev->class = &firmware_class;
 327        dev_set_drvdata(f_dev, fw_priv);
 328        f_dev->uevent_suppress = 1;
 329        retval = device_register(f_dev);
 330        if (retval) {
 331                dev_err(device, "%s: device_register failed\n", __func__);
 332                goto error_kfree;
 333        }
 334        *dev_p = f_dev;
 335        return 0;
 336
 337error_kfree:
 338        kfree(fw_priv);
 339        kfree(f_dev);
 340        return retval;
 341}
 342
 343static int fw_setup_device(struct firmware *fw, struct device **dev_p,
 344                           const char *fw_name, struct device *device,
 345                           int uevent)
 346{
 347        struct device *f_dev;
 348        struct firmware_priv *fw_priv;
 349        int retval;
 350
 351        *dev_p = NULL;
 352        retval = fw_register_device(&f_dev, fw_name, device);
 353        if (retval)
 354                goto out;
 355
 356        /* Need to pin this module until class device is destroyed */
 357        __module_get(THIS_MODULE);
 358
 359        fw_priv = dev_get_drvdata(f_dev);
 360
 361        fw_priv->fw = fw;
 362        retval = sysfs_create_bin_file(&f_dev->kobj, &fw_priv->attr_data);
 363        if (retval) {
 364                dev_err(device, "%s: sysfs_create_bin_file failed\n", __func__);
 365                goto error_unreg;
 366        }
 367
 368        retval = device_create_file(f_dev, &dev_attr_loading);
 369        if (retval) {
 370                dev_err(device, "%s: device_create_file failed\n", __func__);
 371                goto error_unreg;
 372        }
 373
 374        if (uevent)
 375                f_dev->uevent_suppress = 0;
 376        *dev_p = f_dev;
 377        goto out;
 378
 379error_unreg:
 380        device_unregister(f_dev);
 381out:
 382        return retval;
 383}
 384
 385static int
 386_request_firmware(const struct firmware **firmware_p, const char *name,
 387                 struct device *device, int uevent)
 388{
 389        struct device *f_dev;
 390        struct firmware_priv *fw_priv;
 391        struct firmware *firmware;
 392        struct builtin_fw *builtin;
 393        int retval;
 394
 395        if (!firmware_p)
 396                return -EINVAL;
 397
 398        *firmware_p = firmware = kzalloc(sizeof(*firmware), GFP_KERNEL);
 399        if (!firmware) {
 400                dev_err(device, "%s: kmalloc(struct firmware) failed\n",
 401                        __func__);
 402                retval = -ENOMEM;
 403                goto out;
 404        }
 405
 406        for (builtin = __start_builtin_fw; builtin != __end_builtin_fw;
 407             builtin++) {
 408                if (strcmp(name, builtin->name))
 409                        continue;
 410                dev_info(device, "firmware: using built-in firmware %s\n",
 411                         name);
 412                firmware->size = builtin->size;
 413                firmware->data = builtin->data;
 414                return 0;
 415        }
 416
 417        if (uevent)
 418                dev_info(device, "firmware: requesting %s\n", name);
 419
 420        retval = fw_setup_device(firmware, &f_dev, name, device, uevent);
 421        if (retval)
 422                goto error_kfree_fw;
 423
 424        fw_priv = dev_get_drvdata(f_dev);
 425
 426        if (uevent) {
 427                if (loading_timeout > 0) {
 428                        fw_priv->timeout.expires = jiffies + loading_timeout * HZ;
 429                        add_timer(&fw_priv->timeout);
 430                }
 431
 432                kobject_uevent(&f_dev->kobj, KOBJ_ADD);
 433                wait_for_completion(&fw_priv->completion);
 434                set_bit(FW_STATUS_DONE, &fw_priv->status);
 435                del_timer_sync(&fw_priv->timeout);
 436        } else
 437                wait_for_completion(&fw_priv->completion);
 438
 439        mutex_lock(&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        mutex_unlock(&fw_lock);
 447        device_unregister(f_dev);
 448        goto out;
 449
 450error_kfree_fw:
 451        kfree(firmware);
 452        *firmware_p = NULL;
 453out:
 454        return retval;
 455}
 456
 457/**
 458 * request_firmware: - send firmware request and wait for it
 459 * @firmware_p: pointer to firmware image
 460 * @name: name of firmware file
 461 * @device: device for which firmware is being loaded
 462 *
 463 *      @firmware_p will be used to return a firmware image by the name
 464 *      of @name for device @device.
 465 *
 466 *      Should be called from user context where sleeping is allowed.
 467 *
 468 *      @name will be used as $FIRMWARE in the uevent environment and
 469 *      should be distinctive enough not to be confused with any other
 470 *      firmware image for this or any other device.
 471 **/
 472int
 473request_firmware(const struct firmware **firmware_p, const char *name,
 474                 struct device *device)
 475{
 476        int uevent = 1;
 477        return _request_firmware(firmware_p, name, device, uevent);
 478}
 479
 480/**
 481 * release_firmware: - release the resource associated with a firmware image
 482 * @fw: firmware resource to release
 483 **/
 484void
 485release_firmware(const struct firmware *fw)
 486{
 487        struct builtin_fw *builtin;
 488
 489        if (fw) {
 490                for (builtin = __start_builtin_fw; builtin != __end_builtin_fw;
 491                     builtin++) {
 492                        if (fw->data == builtin->data)
 493                                goto free_fw;
 494                }
 495                vfree(fw->data);
 496        free_fw:
 497                kfree(fw);
 498        }
 499}
 500
 501/* Async support */
 502struct firmware_work {
 503        struct work_struct work;
 504        struct module *module;
 505        const char *name;
 506        struct device *device;
 507        void *context;
 508        void (*cont)(const struct firmware *fw, void *context);
 509        int uevent;
 510};
 511
 512static int
 513request_firmware_work_func(void *arg)
 514{
 515        struct firmware_work *fw_work = arg;
 516        const struct firmware *fw;
 517        int ret;
 518        if (!arg) {
 519                WARN_ON(1);
 520                return 0;
 521        }
 522        ret = _request_firmware(&fw, fw_work->name, fw_work->device,
 523                fw_work->uevent);
 524        if (ret < 0)
 525                fw_work->cont(NULL, fw_work->context);
 526        else {
 527                fw_work->cont(fw, fw_work->context);
 528                release_firmware(fw);
 529        }
 530        module_put(fw_work->module);
 531        kfree(fw_work);
 532        return ret;
 533}
 534
 535/**
 536 * request_firmware_nowait: asynchronous version of request_firmware
 537 * @module: module requesting the firmware
 538 * @uevent: sends uevent to copy the firmware image if this flag
 539 *      is non-zero else the firmware copy must be done manually.
 540 * @name: name of firmware file
 541 * @device: device for which firmware is being loaded
 542 * @context: will be passed over to @cont, and
 543 *      @fw may be %NULL if firmware request fails.
 544 * @cont: function will be called asynchronously when the firmware
 545 *      request is over.
 546 *
 547 *      Asynchronous variant of request_firmware() for contexts where
 548 *      it is not possible to sleep.
 549 **/
 550int
 551request_firmware_nowait(
 552        struct module *module, int uevent,
 553        const char *name, struct device *device, void *context,
 554        void (*cont)(const struct firmware *fw, void *context))
 555{
 556        struct task_struct *task;
 557        struct firmware_work *fw_work = kmalloc(sizeof (struct firmware_work),
 558                                                GFP_ATOMIC);
 559
 560        if (!fw_work)
 561                return -ENOMEM;
 562        if (!try_module_get(module)) {
 563                kfree(fw_work);
 564                return -EFAULT;
 565        }
 566
 567        *fw_work = (struct firmware_work) {
 568                .module = module,
 569                .name = name,
 570                .device = device,
 571                .context = context,
 572                .cont = cont,
 573                .uevent = uevent,
 574        };
 575
 576        task = kthread_run(request_firmware_work_func, fw_work,
 577                            "firmware/%s", name);
 578
 579        if (IS_ERR(task)) {
 580                fw_work->cont(NULL, fw_work->context);
 581                module_put(fw_work->module);
 582                kfree(fw_work);
 583                return PTR_ERR(task);
 584        }
 585        return 0;
 586}
 587
 588static int __init
 589firmware_class_init(void)
 590{
 591        int error;
 592        error = class_register(&firmware_class);
 593        if (error) {
 594                printk(KERN_ERR "%s: class_register failed\n", __func__);
 595                return error;
 596        }
 597        error = class_create_file(&firmware_class, &class_attr_timeout);
 598        if (error) {
 599                printk(KERN_ERR "%s: class_create_file failed\n",
 600                       __func__);
 601                class_unregister(&firmware_class);
 602        }
 603        return error;
 604
 605}
 606static void __exit
 607firmware_class_exit(void)
 608{
 609        class_unregister(&firmware_class);
 610}
 611
 612fs_initcall(firmware_class_init);
 613module_exit(firmware_class_exit);
 614
 615EXPORT_SYMBOL(release_firmware);
 616EXPORT_SYMBOL(request_firmware);
 617EXPORT_SYMBOL(request_firmware_nowait);
 618