firmware_class.c 18.1 KB
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/*
 * firmware_class.c - Multi purpose firmware loading support
 *
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 * Copyright (c) 2003 Manuel Estrada Sainz
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 *
 * Please see Documentation/firmware_class/ for more information.
 *
 */

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#include <linux/capability.h>
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#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>
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#include <linux/mutex.h>
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#include <linux/kthread.h>
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#include <linux/highmem.h>
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#include <linux/firmware.h>
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#include <linux/slab.h>
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#define to_dev(obj) container_of(obj, struct device, kobj)

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MODULE_AUTHOR("Manuel Estrada Sainz");
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MODULE_DESCRIPTION("Multi purpose firmware loading support");
MODULE_LICENSE("GPL");

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/* 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

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enum {
	FW_STATUS_LOADING,
	FW_STATUS_DONE,
	FW_STATUS_ABORT,
};

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static int loading_timeout = 60;	/* In seconds */
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static inline long firmware_loading_timeout(void)
{
	return loading_timeout > 0 ? loading_timeout * HZ : MAX_SCHEDULE_TIMEOUT;
}

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/* fw_lock could be moved to 'struct firmware_priv' but since it is just
 * guarding for corner cases a global lock should be OK */
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static DEFINE_MUTEX(fw_lock);
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struct firmware_priv {
	struct completion completion;
	struct firmware *fw;
	unsigned long status;
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	struct page **pages;
	int nr_pages;
	int page_array_size;
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	struct timer_list timeout;
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	struct device dev;
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	bool nowait;
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	char fw_id[];
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};

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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)
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{
	set_bit(FW_STATUS_ABORT, &fw_priv->status);
	wmb();
	complete(&fw_priv->completion);
}

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static ssize_t firmware_timeout_show(struct class *class,
				     struct class_attribute *attr,
				     char *buf)
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{
	return sprintf(buf, "%d\n", loading_timeout);
}

/**
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 * firmware_timeout_store - set number of seconds to wait for firmware
 * @class: device class pointer
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 * @attr: device attribute pointer
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 * @buf: buffer to scan for timeout value
 * @count: number of bytes in @buf
 *
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 *	Sets the number of seconds to wait for the firmware.  Once
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 *	this expires an error will be returned to the driver and no
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 *	firmware will be provided.
 *
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 *	Note: zero means 'wait forever'.
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 **/
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static ssize_t firmware_timeout_store(struct class *class,
				      struct class_attribute *attr,
				      const char *buf, size_t count)
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{
	loading_timeout = simple_strtol(buf, NULL, 10);
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	if (loading_timeout < 0)
		loading_timeout = 0;
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	return count;
}

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static struct class_attribute firmware_class_attrs[] = {
	__ATTR(timeout, S_IWUSR | S_IRUGO,
		firmware_timeout_show, firmware_timeout_store),
	__ATTR_NULL
};
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static void fw_dev_release(struct device *dev)
{
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	struct firmware_priv *fw_priv = to_firmware_priv(dev);
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	int i;

	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);
}
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static int firmware_uevent(struct device *dev, struct kobj_uevent_env *env)
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{
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	struct firmware_priv *fw_priv = to_firmware_priv(dev);
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	if (add_uevent_var(env, "FIRMWARE=%s", fw_priv->fw_id))
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		return -ENOMEM;
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	if (add_uevent_var(env, "TIMEOUT=%i", loading_timeout))
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		return -ENOMEM;
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	if (add_uevent_var(env, "ASYNC=%d", fw_priv->nowait))
		return -ENOMEM;
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	return 0;
}

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static struct class firmware_class = {
	.name		= "firmware",
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	.class_attrs	= firmware_class_attrs,
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	.dev_uevent	= firmware_uevent,
	.dev_release	= fw_dev_release,
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};

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static ssize_t firmware_loading_show(struct device *dev,
				     struct device_attribute *attr, char *buf)
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{
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	struct firmware_priv *fw_priv = to_firmware_priv(dev);
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	int loading = test_bit(FW_STATUS_LOADING, &fw_priv->status);
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	return sprintf(buf, "%d\n", loading);
}

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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);
	}
}

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/* Some architectures don't have PAGE_KERNEL_RO */
#ifndef PAGE_KERNEL_RO
#define PAGE_KERNEL_RO PAGE_KERNEL
#endif
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/**
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 * firmware_loading_store - set value in the 'loading' control file
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 * @dev: device pointer
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 * @attr: device attribute pointer
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 * @buf: buffer to scan for loading control value
 * @count: number of bytes in @buf
 *
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 *	The relevant values are:
 *
 *	 1: Start a load, discarding any previous partial load.
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 *	 0: Conclude the load and hand the data to the driver code.
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 *	-1: Conclude the load with an error and discard any written data.
 **/
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static ssize_t firmware_loading_store(struct device *dev,
				      struct device_attribute *attr,
				      const char *buf, size_t count)
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{
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	struct firmware_priv *fw_priv = to_firmware_priv(dev);
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	int loading = simple_strtol(buf, NULL, 10);
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	int i;
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	mutex_lock(&fw_lock);

	if (!fw_priv->fw)
		goto out;

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	switch (loading) {
	case 1:
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		firmware_free_data(fw_priv->fw);
		memset(fw_priv->fw, 0, sizeof(struct firmware));
		/* If the pages are not owned by 'struct firmware' */
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		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;
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		set_bit(FW_STATUS_LOADING, &fw_priv->status);
		break;
	case 0:
		if (test_bit(FW_STATUS_LOADING, &fw_priv->status)) {
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			vunmap(fw_priv->fw->data);
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			fw_priv->fw->data = vmap(fw_priv->pages,
						 fw_priv->nr_pages,
						 0, PAGE_KERNEL_RO);
			if (!fw_priv->fw->data) {
				dev_err(dev, "%s: vmap() failed\n", __func__);
				goto err;
			}
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			/* Pages are now owned by 'struct firmware' */
			fw_priv->fw->pages = fw_priv->pages;
			fw_priv->pages = NULL;

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			fw_priv->page_array_size = 0;
			fw_priv->nr_pages = 0;
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			complete(&fw_priv->completion);
			clear_bit(FW_STATUS_LOADING, &fw_priv->status);
			break;
		}
		/* fallthrough */
	default:
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		dev_err(dev, "%s: unexpected value (%d)\n", __func__, loading);
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		/* fallthrough */
	case -1:
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	err:
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		fw_load_abort(fw_priv);
		break;
	}
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out:
	mutex_unlock(&fw_lock);
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	return count;
}

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static DEVICE_ATTR(loading, 0644, firmware_loading_show, firmware_loading_store);
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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)
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{
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	struct device *dev = to_dev(kobj);
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	struct firmware_priv *fw_priv = to_firmware_priv(dev);
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	struct firmware *fw;
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	ssize_t ret_count;
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	mutex_lock(&fw_lock);
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	fw = fw_priv->fw;
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	if (!fw || test_bit(FW_STATUS_DONE, &fw_priv->status)) {
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		ret_count = -ENODEV;
		goto out;
	}
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	if (offset > fw->size) {
		ret_count = 0;
		goto out;
	}
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	if (count > fw->size - offset)
		count = fw->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;
	}
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out:
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	mutex_unlock(&fw_lock);
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	return ret_count;
}
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static int fw_realloc_buffer(struct firmware_priv *fw_priv, int min_size)
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{
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	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;
	}
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	while (fw_priv->nr_pages < pages_needed) {
		fw_priv->pages[fw_priv->nr_pages] =
			alloc_page(GFP_KERNEL | __GFP_HIGHMEM);
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		if (!fw_priv->pages[fw_priv->nr_pages]) {
			fw_load_abort(fw_priv);
			return -ENOMEM;
		}
		fw_priv->nr_pages++;
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	}
	return 0;
}

/**
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 * firmware_data_write - write method for firmware
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 * @filp: open sysfs file
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 * @kobj: kobject for the device
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 * @bin_attr: bin_attr structure
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 * @buffer: buffer being written
 * @offset: buffer offset for write in total data store area
 * @count: buffer size
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 *
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 *	Data written to the 'data' attribute will be later handed to
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 *	the driver as a firmware image.
 **/
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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)
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{
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	struct device *dev = to_dev(kobj);
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	struct firmware_priv *fw_priv = to_firmware_priv(dev);
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	struct firmware *fw;
	ssize_t retval;

	if (!capable(CAP_SYS_RAWIO))
		return -EPERM;
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	mutex_lock(&fw_lock);
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	fw = fw_priv->fw;
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	if (!fw || test_bit(FW_STATUS_DONE, &fw_priv->status)) {
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		retval = -ENODEV;
		goto out;
	}
	retval = fw_realloc_buffer(fw_priv, offset + count);
	if (retval)
		goto out;

	retval = count;
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	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->size = max_t(size_t, offset, fw->size);
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out:
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	mutex_unlock(&fw_lock);
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	return retval;
}
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static struct bin_attribute firmware_attr_data = {
	.attr = { .name = "data", .mode = 0644 },
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	.size = 0,
	.read = firmware_data_read,
	.write = firmware_data_write,
};

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static void firmware_class_timeout(u_long data)
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{
	struct firmware_priv *fw_priv = (struct firmware_priv *) data;
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	fw_load_abort(fw_priv);
}

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static struct firmware_priv *
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fw_create_instance(const struct firmware *firmware, const char *fw_name,
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		   struct device *device, bool uevent, bool nowait)
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{
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	struct firmware_priv *fw_priv;
	struct device *f_dev;
	int error;
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	fw_priv = kzalloc(sizeof(*fw_priv) + strlen(fw_name) + 1 , GFP_KERNEL);
	if (!fw_priv) {
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		dev_err(device, "%s: kmalloc failed\n", __func__);
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		error = -ENOMEM;
		goto err_out;
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	}

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	fw_priv->fw = (struct firmware *)firmware;
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	fw_priv->nowait = nowait;
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	strcpy(fw_priv->fw_id, fw_name);
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	init_completion(&fw_priv->completion);
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	setup_timer(&fw_priv->timeout,
		    firmware_class_timeout, (u_long) fw_priv);
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	f_dev = &fw_priv->dev;

	device_initialize(f_dev);
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	dev_set_name(f_dev, "%s", dev_name(device));
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	f_dev->parent = device;
	f_dev->class = &firmware_class;
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	dev_set_uevent_suppress(f_dev, true);
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	/* Need to pin this module until class device is destroyed */
	__module_get(THIS_MODULE);

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	error = device_add(f_dev);
	if (error) {
		dev_err(device, "%s: device_register failed\n", __func__);
		goto err_put_dev;
	}
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	error = device_create_bin_file(f_dev, &firmware_attr_data);
	if (error) {
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		dev_err(device, "%s: sysfs_create_bin_file failed\n", __func__);
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		goto err_del_dev;
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	}

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	error = device_create_file(f_dev, &dev_attr_loading);
	if (error) {
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		dev_err(device, "%s: device_create_file failed\n", __func__);
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		goto err_del_bin_attr;
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	}

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	if (uevent)
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		dev_set_uevent_suppress(f_dev, false);

	return fw_priv;

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);
err_out:
	return ERR_PTR(error);
}

static void fw_destroy_instance(struct firmware_priv *fw_priv)
{
	struct device *f_dev = &fw_priv->dev;
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	device_remove_file(f_dev, &dev_attr_loading);
	device_remove_bin_file(f_dev, &firmware_attr_data);
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	device_unregister(f_dev);
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}

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static int _request_firmware_prepare(const struct firmware **firmware_p,
				     const char *name, struct device *device)
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{
	struct firmware *firmware;

	if (!firmware_p)
		return -EINVAL;

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	*firmware_p = firmware = kzalloc(sizeof(*firmware), GFP_KERNEL);
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	if (!firmware) {
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		dev_err(device, "%s: kmalloc(struct firmware) failed\n",
			__func__);
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		return -ENOMEM;
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	}

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	if (fw_get_builtin_firmware(firmware, name)) {
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		dev_dbg(device, "firmware: using built-in firmware %s\n", name);
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		return 0;
	}

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	return 1;
}

static void _request_firmware_cleanup(const struct firmware **firmware_p)
{
	release_firmware(*firmware_p);
	*firmware_p = NULL;
}

static int _request_firmware(const struct firmware *firmware,
			     const char *name, struct device *device,
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			     bool uevent, bool nowait, long timeout)
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{
	struct firmware_priv *fw_priv;
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	int retval = 0;
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	if (uevent)
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		dev_dbg(device, "firmware: requesting %s\n", name);
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	fw_priv = fw_create_instance(firmware, name, device, uevent, nowait);
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	if (IS_ERR(fw_priv))
		return PTR_ERR(fw_priv);
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	if (uevent) {
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		if (timeout != MAX_SCHEDULE_TIMEOUT)
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			mod_timer(&fw_priv->timeout,
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				  round_jiffies_up(jiffies + timeout));
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		kobject_uevent(&fw_priv->dev.kobj, KOBJ_ADD);
	}

	wait_for_completion(&fw_priv->completion);
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	set_bit(FW_STATUS_DONE, &fw_priv->status);
	del_timer_sync(&fw_priv->timeout);
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	mutex_lock(&fw_lock);
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	if (!fw_priv->fw->size || test_bit(FW_STATUS_ABORT, &fw_priv->status))
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		retval = -ENOENT;
	fw_priv->fw = NULL;
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	mutex_unlock(&fw_lock);
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	fw_destroy_instance(fw_priv);
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	return retval;
}

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/**
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 * request_firmware: - send firmware request and wait for it
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 * @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
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 *      of @name for device @device.
 *
 *      Should be called from user context where sleeping is allowed.
 *
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 *      @name will be used as $FIRMWARE in the uevent environment and
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 *      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)
{
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	int ret;

	ret = _request_firmware_prepare(firmware_p, name, device);
	if (ret <= 0)
		return ret;

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	ret = usermodehelper_read_trylock();
	if (WARN_ON(ret)) {
		dev_err(device, "firmware: %s will not be loaded\n", name);
	} else {
		ret = _request_firmware(*firmware_p, name, device, true, false,
					firmware_loading_timeout());
		usermodehelper_read_unlock();
	}
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	if (ret)
		_request_firmware_cleanup(firmware_p);

	return ret;
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}

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/**
 * release_firmware: - release the resource associated with a firmware image
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 * @fw: firmware resource to release
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 **/
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void release_firmware(const struct firmware *fw)
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{
	if (fw) {
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		if (!fw_is_builtin_firmware(fw))
			firmware_free_data(fw);
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		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);
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	bool uevent;
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};

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static int request_firmware_work_func(void *arg)
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{
	struct firmware_work *fw_work = arg;
	const struct firmware *fw;
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	long timeout;
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	int ret;
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	if (!arg) {
		WARN_ON(1);
		return 0;
	}
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	ret = _request_firmware_prepare(&fw, fw_work->name, fw_work->device);
	if (ret <= 0)
		goto out;

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	timeout = usermodehelper_read_lock_wait(firmware_loading_timeout());
	if (timeout) {
		ret = _request_firmware(fw, fw_work->name, fw_work->device,
					fw_work->uevent, true, timeout);
		usermodehelper_read_unlock();
	} else {
		dev_dbg(fw_work->device, "firmware: %s loading timed out\n",
			fw_work->name);
		ret = -EAGAIN;
	}
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	if (ret)
		_request_firmware_cleanup(&fw);

 out:
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	fw_work->cont(fw, fw_work->context);

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	module_put(fw_work->module);
	kfree(fw_work);
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	return ret;
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}

/**
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 * request_firmware_nowait - asynchronous version of request_firmware
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 * @module: module requesting the firmware
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 * @uevent: sends uevent to copy the firmware image if this flag
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 *	is non-zero else the firmware copy must be done manually.
 * @name: name of firmware file
 * @device: device for which firmware is being loaded
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 * @gfp: allocation flags
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 * @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.
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 *
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 *	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.
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 **/
int
request_firmware_nowait(
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	struct module *module, bool uevent,
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	const char *name, struct device *device, gfp_t gfp, void *context,
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	void (*cont)(const struct firmware *fw, void *context))
{
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	struct task_struct *task;
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	struct firmware_work *fw_work;
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	fw_work = kzalloc(sizeof (struct firmware_work), gfp);
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	if (!fw_work)
		return -ENOMEM;
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	fw_work->module = module;
	fw_work->name = name;
	fw_work->device = device;
	fw_work->context = context;
	fw_work->cont = cont;
	fw_work->uevent = uevent;

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	if (!try_module_get(module)) {
		kfree(fw_work);
		return -EFAULT;
	}

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	task = kthread_run(request_firmware_work_func, fw_work,
			    "firmware/%s", name);
	if (IS_ERR(task)) {
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		fw_work->cont(NULL, fw_work->context);
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		module_put(fw_work->module);
		kfree(fw_work);
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		return PTR_ERR(task);
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	}
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	return 0;
}

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static int __init firmware_class_init(void)
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{
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	return class_register(&firmware_class);
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}
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static void __exit firmware_class_exit(void)
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{
	class_unregister(&firmware_class);
}

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fs_initcall(firmware_class_init);
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module_exit(firmware_class_exit);

EXPORT_SYMBOL(release_firmware);
EXPORT_SYMBOL(request_firmware);
EXPORT_SYMBOL(request_firmware_nowait);