Skip to content
Snippets Groups Projects
Select Git revision
  • ac1f7c159996e98779d36c9ad0989e3b6ef540ab
  • master default protected
  • android-msm-bullhead-3.10-nougat_kgdb_less_changes
  • android-msm-bullhead-3.10-nougat_kgdb
  • android-msm-bullhead-3.10-nougat_klist
  • android-4.4
  • android-msm-vega-4.4-oreo-daydream
  • android-msm-wahoo-4.4-p-preview-5
  • android-msm-wahoo-4.4-pie
  • android-msm-marlin-3.18-p-preview-5
  • android-msm-marlin-3.18-pie
  • android-msm-wahoo-2018.07-oreo-m2
  • android-msm-wahoo-2018.07-oreo-m4
  • android-msm-wahoo-4.4-p-preview-4
  • android-msm-bullhead-3.10-oreo-m6
  • android-msm-angler-3.10-oreo-m6
  • android-msm-marlin-3.18-p-preview-4
  • android-msm-stargazer-3.18-oreo-wear-dr
  • android-msm-catshark-3.18-oreo-wear-dr
  • android-msm-wahoo-4.4-oreo-m2
  • android-msm-wahoo-4.4-oreo-m4
  • android-daydreamos-8.0.0_r0.5
  • android-8.1.0_r0.92
  • android-8.1.0_r0.91
  • android-daydreamos-8.0.0_r0.4
  • android-p-preview-5_r0.2
  • android-p-preview-5_r0.1
  • android-9.0.0_r0.5
  • android-9.0.0_r0.4
  • android-9.0.0_r0.2
  • android-9.0.0_r0.1
  • android-8.1.0_r0.81
  • android-8.1.0_r0.80
  • android-8.1.0_r0.78
  • android-8.1.0_r0.76
  • android-8.1.0_r0.75
  • android-8.1.0_r0.72
  • android-8.1.0_r0.70
  • android-p-preview-4_r0.2
  • android-p-preview-4_r0.1
  • android-wear-8.0.0_r0.30
41 results

clcd.h

Blame
  • firmware_class.c 18.07 KiB
    /*
     * firmware_class.c - Multi purpose firmware loading support
     *
     * Copyright (c) 2003 Manuel Estrada Sainz
     *
     * Please see Documentation/firmware_class/ for more information.
     *
     */
    
    #include <linux/capability.h>
    #include <linux/device.h>
    #include <linux/module.h>
    #include <linux/init.h>
    #include <linux/timer.h>
    #include <linux/vmalloc.h>
    #include <linux/interrupt.h>
    #include <linux/bitops.h>
    #include <linux/mutex.h>
    #include <linux/workqueue.h>
    #include <linux/highmem.h>
    #include <linux/firmware.h>
    #include <linux/slab.h>
    #include <linux/sched.h>
    
    MODULE_AUTHOR("Manuel Estrada Sainz");
    MODULE_DESCRIPTION("Multi purpose firmware loading support");
    MODULE_LICENSE("GPL");
    
    /* Builtin firmware support */
    
    #ifdef CONFIG_FW_LOADER
    
    extern struct builtin_fw __start_builtin_fw[];
    extern struct builtin_fw __end_builtin_fw[];
    
    static bool fw_get_builtin_firmware(struct firmware *fw, const char *name)
    {
    	struct builtin_fw *b_fw;
    
    	for (b_fw = __start_builtin_fw; b_fw != __end_builtin_fw; b_fw++) {
    		if (strcmp(name, b_fw->name) == 0) {
    			fw->size = b_fw->size;
    			fw->data = b_fw->data;
    			return true;
    		}
    	}
    
    	return false;
    }
    
    static bool fw_is_builtin_firmware(const struct firmware *fw)
    {
    	struct builtin_fw *b_fw;
    
    	for (b_fw = __start_builtin_fw; b_fw != __end_builtin_fw; b_fw++)
    		if (fw->data == b_fw->data)
    			return true;
    
    	return false;
    }
    
    #else /* Module case - no builtin firmware support */
    
    static inline bool fw_get_builtin_firmware(struct firmware *fw, const char *name)
    {
    	return false;
    }
    
    static inline bool fw_is_builtin_firmware(const struct firmware *fw)
    {
    	return false;
    }
    #endif
    
    enum {
    	FW_STATUS_LOADING,
    	FW_STATUS_DONE,
    	FW_STATUS_ABORT,
    };
    
    static int loading_timeout = 60;	/* In seconds */
    
    static inline long firmware_loading_timeout(void)
    {
    	return loading_timeout > 0 ? loading_timeout * HZ : MAX_SCHEDULE_TIMEOUT;
    }
    
    /* fw_lock could be moved to 'struct firmware_priv' but since it is just
     * guarding for corner cases a global lock should be OK */
    static DEFINE_MUTEX(fw_lock);
    
    struct firmware_priv {
    	struct completion completion;
    	struct firmware *fw;
    	unsigned long status;
    	void *data;
    	size_t size;
    	struct page **pages;
    	int nr_pages;
    	int page_array_size;
    	struct timer_list timeout;
    	struct device dev;
    	bool nowait;
    	char fw_id[];
    };
    
    static struct firmware_priv *to_firmware_priv(struct device *dev)
    {
    	return container_of(dev, struct firmware_priv, dev);
    }
    
    static void fw_load_abort(struct firmware_priv *fw_priv)
    {
    	set_bit(FW_STATUS_ABORT, &fw_priv->status);
    	complete(&fw_priv->completion);
    }
    
    static ssize_t firmware_timeout_show(struct class *class,
    				     struct class_attribute *attr,
    				     char *buf)
    {
    	return sprintf(buf, "%d\n", loading_timeout);
    }
    
    /**
     * firmware_timeout_store - set number of seconds to wait for firmware
     * @class: device class pointer
     * @attr: device attribute pointer
     * @buf: buffer to scan for timeout value
     * @count: number of bytes in @buf
     *
     *	Sets the number of seconds to wait for the firmware.  Once
     *	this expires an error will be returned to the driver and no
     *	firmware will be provided.
     *
     *	Note: zero means 'wait forever'.
     **/
    static ssize_t firmware_timeout_store(struct class *class,
    				      struct class_attribute *attr,
    				      const char *buf, size_t count)
    {
    	loading_timeout = simple_strtol(buf, NULL, 10);
    	if (loading_timeout < 0)
    		loading_timeout = 0;
    
    	return count;
    }
    
    static struct class_attribute firmware_class_attrs[] = {
    	__ATTR(timeout, S_IWUSR | S_IRUGO,
    		firmware_timeout_show, firmware_timeout_store),
    	__ATTR_NULL
    };
    
    static void fw_dev_release(struct device *dev)
    {
    	struct firmware_priv *fw_priv = to_firmware_priv(dev);
    	int i;
    
    	/* free untransfered pages buffer */
    	for (i = 0; i < fw_priv->nr_pages; i++)
    		__free_page(fw_priv->pages[i]);
    	kfree(fw_priv->pages);
    
    	kfree(fw_priv);
    
    	module_put(THIS_MODULE);
    }
    
    static int firmware_uevent(struct device *dev, struct kobj_uevent_env *env)
    {
    	struct firmware_priv *fw_priv = to_firmware_priv(dev);
    
    	if (add_uevent_var(env, "FIRMWARE=%s", fw_priv->fw_id))
    		return -ENOMEM;
    	if (add_uevent_var(env, "TIMEOUT=%i", loading_timeout))
    		return -ENOMEM;
    	if (add_uevent_var(env, "ASYNC=%d", fw_priv->nowait))
    		return -ENOMEM;
    
    	return 0;
    }
    
    static struct class firmware_class = {
    	.name		= "firmware",
    	.class_attrs	= firmware_class_attrs,
    	.dev_uevent	= firmware_uevent,
    	.dev_release	= fw_dev_release,
    };
    
    static ssize_t firmware_loading_show(struct device *dev,
    				     struct device_attribute *attr, char *buf)
    {
    	struct firmware_priv *fw_priv = to_firmware_priv(dev);
    	int loading = test_bit(FW_STATUS_LOADING, &fw_priv->status);
    
    	return sprintf(buf, "%d\n", loading);
    }
    
    /* firmware holds the ownership of pages */
    static void firmware_free_data(const struct firmware *fw)
    {
    	int i;
    	vunmap(fw->data);
    	if (fw->pages) {
    		for (i = 0; i < PFN_UP(fw->size); i++)
    			__free_page(fw->pages[i]);
    		kfree(fw->pages);
    	}
    }
    
    /* Some architectures don't have PAGE_KERNEL_RO */
    #ifndef PAGE_KERNEL_RO
    #define PAGE_KERNEL_RO PAGE_KERNEL
    #endif
    /**
     * firmware_loading_store - set value in the 'loading' control file
     * @dev: device pointer
     * @attr: device attribute pointer
     * @buf: buffer to scan for loading control value
     * @count: number of bytes in @buf
     *
     *	The relevant values are:
     *
     *	 1: Start a load, discarding any previous partial load.
     *	 0: Conclude the load and hand the data to the driver code.
     *	-1: Conclude the load with an error and discard any written data.
     **/
    static ssize_t firmware_loading_store(struct device *dev,
    				      struct device_attribute *attr,
    				      const char *buf, size_t count)
    {
    	struct firmware_priv *fw_priv = to_firmware_priv(dev);
    	int loading = simple_strtol(buf, NULL, 10);
    	int i;
    
    	mutex_lock(&fw_lock);
    
    	if (!fw_priv->fw)
    		goto out;
    
    	switch (loading) {
    	case 1:
    		/* discarding any previous partial load */
    		if (!test_bit(FW_STATUS_DONE, &fw_priv->status)) {
    			for (i = 0; i < fw_priv->nr_pages; i++)
    				__free_page(fw_priv->pages[i]);
    			kfree(fw_priv->pages);
    			fw_priv->pages = NULL;
    			fw_priv->page_array_size = 0;
    			fw_priv->nr_pages = 0;
    			set_bit(FW_STATUS_LOADING, &fw_priv->status);
    		}
    		break;
    	case 0:
    		if (test_bit(FW_STATUS_LOADING, &fw_priv->status)) {
    			set_bit(FW_STATUS_DONE, &fw_priv->status);
    			clear_bit(FW_STATUS_LOADING, &fw_priv->status);
    			complete(&fw_priv->completion);
    			break;
    		}
    		/* fallthrough */
    	default:
    		dev_err(dev, "%s: unexpected value (%d)\n", __func__, loading);
    		/* fallthrough */
    	case -1:
    		fw_load_abort(fw_priv);
    		break;
    	}
    out:
    	mutex_unlock(&fw_lock);
    	return count;
    }
    
    static DEVICE_ATTR(loading, 0644, firmware_loading_show, firmware_loading_store);
    
    static ssize_t firmware_data_read(struct file *filp, struct kobject *kobj,
    				  struct bin_attribute *bin_attr,
    				  char *buffer, loff_t offset, size_t count)
    {
    	struct device *dev = kobj_to_dev(kobj);
    	struct firmware_priv *fw_priv = to_firmware_priv(dev);
    	struct firmware *fw;
    	ssize_t ret_count;
    
    	mutex_lock(&fw_lock);
    	fw = fw_priv->fw;
    	if (!fw || test_bit(FW_STATUS_DONE, &fw_priv->status)) {
    		ret_count = -ENODEV;
    		goto out;
    	}
    	if (offset > fw_priv->size) {
    		ret_count = 0;
    		goto out;
    	}
    	if (count > fw_priv->size - offset)
    		count = fw_priv->size - offset;
    
    	ret_count = count;
    
    	while (count) {
    		void *page_data;
    		int page_nr = offset >> PAGE_SHIFT;
    		int page_ofs = offset & (PAGE_SIZE-1);
    		int page_cnt = min_t(size_t, PAGE_SIZE - page_ofs, count);
    
    		page_data = kmap(fw_priv->pages[page_nr]);
    
    		memcpy(buffer, page_data + page_ofs, page_cnt);
    
    		kunmap(fw_priv->pages[page_nr]);
    		buffer += page_cnt;
    		offset += page_cnt;
    		count -= page_cnt;
    	}
    out:
    	mutex_unlock(&fw_lock);
    	return ret_count;
    }
    
    static int fw_realloc_buffer(struct firmware_priv *fw_priv, int min_size)
    {
    	int pages_needed = ALIGN(min_size, PAGE_SIZE) >> PAGE_SHIFT;
    
    	/* If the array of pages is too small, grow it... */
    	if (fw_priv->page_array_size < pages_needed) {
    		int new_array_size = max(pages_needed,
    					 fw_priv->page_array_size * 2);
    		struct page **new_pages;
    
    		new_pages = kmalloc(new_array_size * sizeof(void *),
    				    GFP_KERNEL);
    		if (!new_pages) {
    			fw_load_abort(fw_priv);
    			return -ENOMEM;
    		}
    		memcpy(new_pages, fw_priv->pages,
    		       fw_priv->page_array_size * sizeof(void *));
    		memset(&new_pages[fw_priv->page_array_size], 0, sizeof(void *) *
    		       (new_array_size - fw_priv->page_array_size));
    		kfree(fw_priv->pages);
    		fw_priv->pages = new_pages;
    		fw_priv->page_array_size = new_array_size;
    	}
    
    	while (fw_priv->nr_pages < pages_needed) {
    		fw_priv->pages[fw_priv->nr_pages] =
    			alloc_page(GFP_KERNEL | __GFP_HIGHMEM);
    
    		if (!fw_priv->pages[fw_priv->nr_pages]) {
    			fw_load_abort(fw_priv);
    			return -ENOMEM;
    		}
    		fw_priv->nr_pages++;
    	}
    	return 0;
    }
    
    /**
     * firmware_data_write - write method for firmware
     * @filp: open sysfs file
     * @kobj: kobject for the device
     * @bin_attr: bin_attr structure
     * @buffer: buffer being written
     * @offset: buffer offset for write in total data store area
     * @count: buffer size
     *
     *	Data written to the 'data' attribute will be later handed to
     *	the driver as a firmware image.
     **/
    static ssize_t firmware_data_write(struct file *filp, struct kobject *kobj,
    				   struct bin_attribute *bin_attr,
    				   char *buffer, loff_t offset, size_t count)
    {
    	struct device *dev = kobj_to_dev(kobj);
    	struct firmware_priv *fw_priv = to_firmware_priv(dev);
    	struct firmware *fw;
    	ssize_t retval;
    
    	if (!capable(CAP_SYS_RAWIO))
    		return -EPERM;
    
    	mutex_lock(&fw_lock);
    	fw = fw_priv->fw;
    	if (!fw || test_bit(FW_STATUS_DONE, &fw_priv->status)) {
    		retval = -ENODEV;
    		goto out;
    	}
    
    	retval = fw_realloc_buffer(fw_priv, offset + count);
    	if (retval)
    		goto out;
    
    	retval = count;
    
    	while (count) {
    		void *page_data;
    		int page_nr = offset >> PAGE_SHIFT;
    		int page_ofs = offset & (PAGE_SIZE - 1);
    		int page_cnt = min_t(size_t, PAGE_SIZE - page_ofs, count);
    
    		page_data = kmap(fw_priv->pages[page_nr]);
    
    		memcpy(page_data + page_ofs, buffer, page_cnt);
    
    		kunmap(fw_priv->pages[page_nr]);
    		buffer += page_cnt;
    		offset += page_cnt;
    		count -= page_cnt;
    	}
    
    	fw_priv->size = max_t(size_t, offset, fw_priv->size);
    out:
    	mutex_unlock(&fw_lock);
    	return retval;
    }
    
    static struct bin_attribute firmware_attr_data = {
    	.attr = { .name = "data", .mode = 0644 },
    	.size = 0,
    	.read = firmware_data_read,
    	.write = firmware_data_write,
    };
    
    static void firmware_class_timeout(u_long data)
    {
    	struct firmware_priv *fw_priv = (struct firmware_priv *) data;
    
    	fw_load_abort(fw_priv);
    }
    
    static struct firmware_priv *
    fw_create_instance(struct firmware *firmware, const char *fw_name,
    		   struct device *device, bool uevent, bool nowait)
    {
    	struct firmware_priv *fw_priv;
    	struct device *f_dev;
    
    	fw_priv = kzalloc(sizeof(*fw_priv) + strlen(fw_name) + 1 , GFP_KERNEL);
    	if (!fw_priv) {
    		dev_err(device, "%s: kmalloc failed\n", __func__);
    		return ERR_PTR(-ENOMEM);
    	}
    
    	fw_priv->fw = firmware;
    	fw_priv->nowait = nowait;
    	strcpy(fw_priv->fw_id, fw_name);
    	init_completion(&fw_priv->completion);
    	setup_timer(&fw_priv->timeout,
    		    firmware_class_timeout, (u_long) fw_priv);
    
    	f_dev = &fw_priv->dev;
    
    	device_initialize(f_dev);
    	dev_set_name(f_dev, "%s", dev_name(device));
    	f_dev->parent = device;
    	f_dev->class = &firmware_class;
    
    	return fw_priv;
    }
    
    static struct firmware_priv *
    _request_firmware_prepare(const struct firmware **firmware_p, const char *name,
    			  struct device *device, bool uevent, bool nowait)
    {
    	struct firmware *firmware;
    	struct firmware_priv *fw_priv;
    
    	if (!firmware_p)
    		return ERR_PTR(-EINVAL);
    
    	*firmware_p = firmware = kzalloc(sizeof(*firmware), GFP_KERNEL);
    	if (!firmware) {
    		dev_err(device, "%s: kmalloc(struct firmware) failed\n",
    			__func__);
    		return ERR_PTR(-ENOMEM);
    	}
    
    	if (fw_get_builtin_firmware(firmware, name)) {
    		dev_dbg(device, "firmware: using built-in firmware %s\n", name);
    		return NULL;
    	}
    
    	fw_priv = fw_create_instance(firmware, name, device, uevent, nowait);
    	if (IS_ERR(fw_priv)) {
    		release_firmware(firmware);
    		*firmware_p = NULL;
    	}
    	return fw_priv;
    }
    
    static void _request_firmware_cleanup(const struct firmware **firmware_p)
    {
    	release_firmware(*firmware_p);
    	*firmware_p = NULL;
    }
    
    /* transfer the ownership of pages to firmware */
    static int fw_set_page_data(struct firmware_priv *fw_priv)
    {
    	struct firmware *fw = fw_priv->fw;
    
    	fw_priv->data = vmap(fw_priv->pages, fw_priv->nr_pages,
    				0, PAGE_KERNEL_RO);
    	if (!fw_priv->data)
    		return -ENOMEM;
    
    	fw->data = fw_priv->data;
    	fw->pages = fw_priv->pages;
    	fw->size = fw_priv->size;
    
    	WARN_ON(PFN_UP(fw->size) != fw_priv->nr_pages);
    
    	fw_priv->nr_pages = 0;
    	fw_priv->pages = NULL;
    	fw_priv->data = NULL;
    
    	return 0;
    }
    
    static int _request_firmware_load(struct firmware_priv *fw_priv, bool uevent,
    				  long timeout)
    {
    	int retval = 0;
    	struct device *f_dev = &fw_priv->dev;
    
    	dev_set_uevent_suppress(f_dev, true);
    
    	/* Need to pin this module until class device is destroyed */
    	__module_get(THIS_MODULE);
    
    	retval = device_add(f_dev);
    	if (retval) {
    		dev_err(f_dev, "%s: device_register failed\n", __func__);
    		goto err_put_dev;
    	}
    
    	retval = device_create_bin_file(f_dev, &firmware_attr_data);
    	if (retval) {
    		dev_err(f_dev, "%s: sysfs_create_bin_file failed\n", __func__);
    		goto err_del_dev;
    	}
    
    	retval = device_create_file(f_dev, &dev_attr_loading);
    	if (retval) {
    		dev_err(f_dev, "%s: device_create_file failed\n", __func__);
    		goto err_del_bin_attr;
    	}
    
    	if (uevent) {
    		dev_set_uevent_suppress(f_dev, false);
    		dev_dbg(f_dev, "firmware: requesting %s\n", fw_priv->fw_id);
    		if (timeout != MAX_SCHEDULE_TIMEOUT)
    			mod_timer(&fw_priv->timeout,
    				  round_jiffies_up(jiffies + timeout));
    
    		kobject_uevent(&fw_priv->dev.kobj, KOBJ_ADD);
    	}
    
    	wait_for_completion(&fw_priv->completion);
    
    	del_timer_sync(&fw_priv->timeout);
    
    	mutex_lock(&fw_lock);
    	if (!fw_priv->size || test_bit(FW_STATUS_ABORT, &fw_priv->status))
    		retval = -ENOENT;
    
    	/* transfer pages ownership at the last minute */
    	if (!retval)
    		retval = fw_set_page_data(fw_priv);
    	fw_priv->fw = NULL;
    	mutex_unlock(&fw_lock);
    
    	device_remove_file(f_dev, &dev_attr_loading);
    err_del_bin_attr:
    	device_remove_bin_file(f_dev, &firmware_attr_data);
    err_del_dev:
    	device_del(f_dev);
    err_put_dev:
    	put_device(f_dev);
    	return retval;
    }
    
    /**
     * request_firmware: - send firmware request and wait for it
     * @firmware_p: pointer to firmware image
     * @name: name of firmware file
     * @device: device for which firmware is being loaded
     *
     *      @firmware_p will be used to return a firmware image by the name
     *      of @name for device @device.
     *
     *      Should be called from user context where sleeping is allowed.
     *
     *      @name will be used as $FIRMWARE in the uevent environment and
     *      should be distinctive enough not to be confused with any other
     *      firmware image for this or any other device.
     **/
    int
    request_firmware(const struct firmware **firmware_p, const char *name,
                     struct device *device)
    {
    	struct firmware_priv *fw_priv;
    	int ret;
    
    	fw_priv = _request_firmware_prepare(firmware_p, name, device, true,
    					    false);
    	if (IS_ERR_OR_NULL(fw_priv))
    		return PTR_RET(fw_priv);
    
    	ret = usermodehelper_read_trylock();
    	if (WARN_ON(ret)) {
    		dev_err(device, "firmware: %s will not be loaded\n", name);
    	} else {
    		ret = _request_firmware_load(fw_priv, true,
    					firmware_loading_timeout());
    		usermodehelper_read_unlock();
    	}
    	if (ret)
    		_request_firmware_cleanup(firmware_p);
    
    	return ret;
    }
    
    /**
     * release_firmware: - release the resource associated with a firmware image
     * @fw: firmware resource to release
     **/
    void release_firmware(const struct firmware *fw)
    {
    	if (fw) {
    		if (!fw_is_builtin_firmware(fw))
    			firmware_free_data(fw);
    		kfree(fw);
    	}
    }
    
    /* Async support */
    struct firmware_work {
    	struct work_struct work;
    	struct module *module;
    	const char *name;
    	struct device *device;
    	void *context;
    	void (*cont)(const struct firmware *fw, void *context);
    	bool uevent;
    };
    
    static void request_firmware_work_func(struct work_struct *work)
    {
    	struct firmware_work *fw_work;
    	const struct firmware *fw;
    	struct firmware_priv *fw_priv;
    	long timeout;
    	int ret;
    
    	fw_work = container_of(work, struct firmware_work, work);
    	fw_priv = _request_firmware_prepare(&fw, fw_work->name, fw_work->device,
    			fw_work->uevent, true);
    	if (IS_ERR_OR_NULL(fw_priv)) {
    		ret = PTR_RET(fw_priv);
    		goto out;
    	}
    
    	timeout = usermodehelper_read_lock_wait(firmware_loading_timeout());
    	if (timeout) {
    		ret = _request_firmware_load(fw_priv, fw_work->uevent, timeout);
    		usermodehelper_read_unlock();
    	} else {
    		dev_dbg(fw_work->device, "firmware: %s loading timed out\n",
    			fw_work->name);
    		ret = -EAGAIN;
    	}
    	if (ret)
    		_request_firmware_cleanup(&fw);
    
     out:
    	fw_work->cont(fw, fw_work->context);
    
    	module_put(fw_work->module);
    	kfree(fw_work);
    }
    
    /**
     * request_firmware_nowait - asynchronous version of request_firmware
     * @module: module requesting the firmware
     * @uevent: sends uevent to copy the firmware image if this flag
     *	is non-zero else the firmware copy must be done manually.
     * @name: name of firmware file
     * @device: device for which firmware is being loaded
     * @gfp: allocation flags
     * @context: will be passed over to @cont, and
     *	@fw may be %NULL if firmware request fails.
     * @cont: function will be called asynchronously when the firmware
     *	request is over.
     *
     *	Asynchronous variant of request_firmware() for user contexts where
     *	it is not possible to sleep for long time. It can't be called
     *	in atomic contexts.
     **/
    int
    request_firmware_nowait(
    	struct module *module, bool uevent,
    	const char *name, struct device *device, gfp_t gfp, void *context,
    	void (*cont)(const struct firmware *fw, void *context))
    {
    	struct firmware_work *fw_work;
    
    	fw_work = kzalloc(sizeof (struct firmware_work), gfp);
    	if (!fw_work)
    		return -ENOMEM;
    
    	fw_work->module = module;
    	fw_work->name = name;
    	fw_work->device = device;
    	fw_work->context = context;
    	fw_work->cont = cont;
    	fw_work->uevent = uevent;
    
    	if (!try_module_get(module)) {
    		kfree(fw_work);
    		return -EFAULT;
    	}
    
    	INIT_WORK(&fw_work->work, request_firmware_work_func);
    	schedule_work(&fw_work->work);
    	return 0;
    }
    
    static int __init firmware_class_init(void)
    {
    	return class_register(&firmware_class);
    }
    
    static void __exit firmware_class_exit(void)
    {
    	class_unregister(&firmware_class);
    }
    
    fs_initcall(firmware_class_init);
    module_exit(firmware_class_exit);
    
    EXPORT_SYMBOL(release_firmware);
    EXPORT_SYMBOL(request_firmware);
    EXPORT_SYMBOL(request_firmware_nowait);