Initial import

1 files changed, 1696 insertions, 0 deletions

diff --git a/drivers/base/firmware_class.c b/drivers/base/firmware_class.c
new file mode 100644
index 000000000..cf3e594f2
--- /dev/null
+++ b/drivers/base/firmware_class.c
@@ -0,0 +1,1696 @@
+/*
+ * 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>
+#include <linux/file.h>
+#include <linux/list.h>
+#include <linux/async.h>
+#include <linux/pm.h>
+#include <linux/suspend.h>
+#include <linux/syscore_ops.h>
+#include <linux/reboot.h>
+#include <linux/security.h>
+
+#include <generated/utsrelease.h>
+
+#include "base.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_JIFFY_OFFSET;
+}
+
+/* firmware behavior options */
+#define FW_OPT_UEVENT	(1U << 0)
+#define FW_OPT_NOWAIT	(1U << 1)
+#ifdef CONFIG_FW_LOADER_USER_HELPER
+#define FW_OPT_USERHELPER	(1U << 2)
+#else
+#define FW_OPT_USERHELPER	0
+#endif
+#ifdef CONFIG_FW_LOADER_USER_HELPER_FALLBACK
+#define FW_OPT_FALLBACK		FW_OPT_USERHELPER
+#else
+#define FW_OPT_FALLBACK		0
+#endif
+#define FW_OPT_NO_WARN	(1U << 3)
+
+struct firmware_cache {
+	/* firmware_buf instance will be added into the below list */
+	spinlock_t lock;
+	struct list_head head;
+	int state;
+
+#ifdef CONFIG_PM_SLEEP
+	/*
+	 * Names of firmware images which have been cached successfully
+	 * will be added into the below list so that device uncache
+	 * helper can trace which firmware images have been cached
+	 * before.
+	 */
+	spinlock_t name_lock;
+	struct list_head fw_names;
+
+	struct delayed_work work;
+
+	struct notifier_block   pm_notify;
+#endif
+};
+
+struct firmware_buf {
+	struct kref ref;
+	struct list_head list;
+	struct completion completion;
+	struct firmware_cache *fwc;
+	unsigned long status;
+	void *data;
+	size_t size;
+#ifdef CONFIG_FW_LOADER_USER_HELPER
+	bool is_paged_buf;
+	bool need_uevent;
+	struct page **pages;
+	int nr_pages;
+	int page_array_size;
+	struct list_head pending_list;
+#endif
+	char fw_id[];
+};
+
+struct fw_cache_entry {
+	struct list_head list;
+	char name[];
+};
+
+struct fw_name_devm {
+	unsigned long magic;
+	char name[];
+};
+
+#define to_fwbuf(d) container_of(d, struct firmware_buf, ref)
+
+#define	FW_LOADER_NO_CACHE	0
+#define	FW_LOADER_START_CACHE	1
+
+static int fw_cache_piggyback_on_request(const char *name);
+
+/* 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);
+
+static struct firmware_cache fw_cache;
+
+static struct firmware_buf *__allocate_fw_buf(const char *fw_name,
+					      struct firmware_cache *fwc)
+{
+	struct firmware_buf *buf;
+
+	buf = kzalloc(sizeof(*buf) + strlen(fw_name) + 1, GFP_ATOMIC);
+
+	if (!buf)
+		return buf;
+
+	kref_init(&buf->ref);
+	strcpy(buf->fw_id, fw_name);
+	buf->fwc = fwc;
+	init_completion(&buf->completion);
+#ifdef CONFIG_FW_LOADER_USER_HELPER
+	INIT_LIST_HEAD(&buf->pending_list);
+#endif
+
+	pr_debug("%s: fw-%s buf=%p\n", __func__, fw_name, buf);
+
+	return buf;
+}
+
+static struct firmware_buf *__fw_lookup_buf(const char *fw_name)
+{
+	struct firmware_buf *tmp;
+	struct firmware_cache *fwc = &fw_cache;
+
+	list_for_each_entry(tmp, &fwc->head, list)
+		if (!strcmp(tmp->fw_id, fw_name))
+			return tmp;
+	return NULL;
+}
+
+static int fw_lookup_and_allocate_buf(const char *fw_name,
+				      struct firmware_cache *fwc,
+				      struct firmware_buf **buf)
+{
+	struct firmware_buf *tmp;
+
+	spin_lock(&fwc->lock);
+	tmp = __fw_lookup_buf(fw_name);
+	if (tmp) {
+		kref_get(&tmp->ref);
+		spin_unlock(&fwc->lock);
+		*buf = tmp;
+		return 1;
+	}
+	tmp = __allocate_fw_buf(fw_name, fwc);
+	if (tmp)
+		list_add(&tmp->list, &fwc->head);
+	spin_unlock(&fwc->lock);
+
+	*buf = tmp;
+
+	return tmp ? 0 : -ENOMEM;
+}
+
+static void __fw_free_buf(struct kref *ref)
+	__releases(&fwc->lock)
+{
+	struct firmware_buf *buf = to_fwbuf(ref);
+	struct firmware_cache *fwc = buf->fwc;
+
+	pr_debug("%s: fw-%s buf=%p data=%p size=%u\n",
+		 __func__, buf->fw_id, buf, buf->data,
+		 (unsigned int)buf->size);
+
+	list_del(&buf->list);
+	spin_unlock(&fwc->lock);
+
+#ifdef CONFIG_FW_LOADER_USER_HELPER
+	if (buf->is_paged_buf) {
+		int i;
+		vunmap(buf->data);
+		for (i = 0; i < buf->nr_pages; i++)
+			__free_page(buf->pages[i]);
+		kfree(buf->pages);
+	} else
+#endif
+		vfree(buf->data);
+	kfree(buf);
+}
+
+static void fw_free_buf(struct firmware_buf *buf)
+{
+	struct firmware_cache *fwc = buf->fwc;
+	spin_lock(&fwc->lock);
+	if (!kref_put(&buf->ref, __fw_free_buf))
+		spin_unlock(&fwc->lock);
+}
+
+/* direct firmware loading support */
+static char fw_path_para[256];
+static const char * const fw_path[] = {
+	fw_path_para,
+	"/lib/firmware/updates/" UTS_RELEASE,
+	"/lib/firmware/updates",
+	"/lib/firmware/" UTS_RELEASE,
+	"/lib/firmware"
+};
+
+/*
+ * Typical usage is that passing 'firmware_class.path=$CUSTOMIZED_PATH'
+ * from kernel command line because firmware_class is generally built in
+ * kernel instead of module.
+ */
+module_param_string(path, fw_path_para, sizeof(fw_path_para), 0644);
+MODULE_PARM_DESC(path, "customized firmware image search path with a higher priority than default path");
+
+static int fw_read_file_contents(struct file *file, struct firmware_buf *fw_buf)
+{
+	int size;
+	char *buf;
+	int rc;
+
+	if (!S_ISREG(file_inode(file)->i_mode))
+		return -EINVAL;
+	size = i_size_read(file_inode(file));
+	if (size <= 0)
+		return -EINVAL;
+	buf = vmalloc(size);
+	if (!buf)
+		return -ENOMEM;
+	rc = kernel_read(file, 0, buf, size);
+	if (rc != size) {
+		if (rc > 0)
+			rc = -EIO;
+		goto fail;
+	}
+	rc = security_kernel_fw_from_file(file, buf, size);
+	if (rc)
+		goto fail;
+	fw_buf->data = buf;
+	fw_buf->size = size;
+	return 0;
+fail:
+	vfree(buf);
+	return rc;
+}
+
+static int fw_get_filesystem_firmware(struct device *device,
+				       struct firmware_buf *buf)
+{
+	int i;
+	int rc = -ENOENT;
+	char *path = __getname();
+
+	for (i = 0; i < ARRAY_SIZE(fw_path); i++) {
+		struct file *file;
+
+		/* skip the unset customized path */
+		if (!fw_path[i][0])
+			continue;
+
+		snprintf(path, PATH_MAX, "%s/%s", fw_path[i], buf->fw_id);
+
+		file = filp_open(path, O_RDONLY, 0);
+		if (IS_ERR(file))
+			continue;
+		rc = fw_read_file_contents(file, buf);
+		fput(file);
+		if (rc)
+			dev_warn(device, "firmware, attempted to load %s, but failed with error %d\n",
+				path, rc);
+		else
+			break;
+	}
+	__putname(path);
+
+	if (!rc) {
+		dev_dbg(device, "firmware: direct-loading firmware %s\n",
+			buf->fw_id);
+		mutex_lock(&fw_lock);
+		set_bit(FW_STATUS_DONE, &buf->status);
+		complete_all(&buf->completion);
+		mutex_unlock(&fw_lock);
+	}
+
+	return rc;
+}
+
+/* firmware holds the ownership of pages */
+static void firmware_free_data(const struct firmware *fw)
+{
+	/* Loaded directly? */
+	if (!fw->priv) {
+		vfree(fw->data);
+		return;
+	}
+	fw_free_buf(fw->priv);
+}
+
+/* store the pages buffer info firmware from buf */
+static void fw_set_page_data(struct firmware_buf *buf, struct firmware *fw)
+{
+	fw->priv = buf;
+#ifdef CONFIG_FW_LOADER_USER_HELPER
+	fw->pages = buf->pages;
+#endif
+	fw->size = buf->size;
+	fw->data = buf->data;
+
+	pr_debug("%s: fw-%s buf=%p data=%p size=%u\n",
+		 __func__, buf->fw_id, buf, buf->data,
+		 (unsigned int)buf->size);
+}
+
+#ifdef CONFIG_PM_SLEEP
+static void fw_name_devm_release(struct device *dev, void *res)
+{
+	struct fw_name_devm *fwn = res;
+
+	if (fwn->magic == (unsigned long)&fw_cache)
+		pr_debug("%s: fw_name-%s devm-%p released\n",
+				__func__, fwn->name, res);
+}
+
+static int fw_devm_match(struct device *dev, void *res,
+		void *match_data)
+{
+	struct fw_name_devm *fwn = res;
+
+	return (fwn->magic == (unsigned long)&fw_cache) &&
+		!strcmp(fwn->name, match_data);
+}
+
+static struct fw_name_devm *fw_find_devm_name(struct device *dev,
+		const char *name)
+{
+	struct fw_name_devm *fwn;
+
+	fwn = devres_find(dev, fw_name_devm_release,
+			  fw_devm_match, (void *)name);
+	return fwn;
+}
+
+/* add firmware name into devres list */
+static int fw_add_devm_name(struct device *dev, const char *name)
+{
+	struct fw_name_devm *fwn;
+
+	fwn = fw_find_devm_name(dev, name);
+	if (fwn)
+		return 1;
+
+	fwn = devres_alloc(fw_name_devm_release, sizeof(struct fw_name_devm) +
+			   strlen(name) + 1, GFP_KERNEL);
+	if (!fwn)
+		return -ENOMEM;
+
+	fwn->magic = (unsigned long)&fw_cache;
+	strcpy(fwn->name, name);
+	devres_add(dev, fwn);
+
+	return 0;
+}
+#else
+static int fw_add_devm_name(struct device *dev, const char *name)
+{
+	return 0;
+}
+#endif
+
+
+/*
+ * user-mode helper code
+ */
+#ifdef CONFIG_FW_LOADER_USER_HELPER
+struct firmware_priv {
+	bool nowait;
+	struct device dev;
+	struct firmware_buf *buf;
+	struct firmware *fw;
+};
+
+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_buf *buf)
+{
+	/*
+	 * There is a small window in which user can write to 'loading'
+	 * between loading done and disappearance of 'loading'
+	 */
+	if (test_bit(FW_STATUS_DONE, &buf->status))
+		return;
+
+	list_del_init(&buf->pending_list);
+	set_bit(FW_STATUS_ABORT, &buf->status);
+	complete_all(&buf->completion);
+}
+
+static void fw_load_abort(struct firmware_priv *fw_priv)
+{
+	struct firmware_buf *buf = fw_priv->buf;
+
+	__fw_load_abort(buf);
+
+	/* avoid user action after loading abort */
+	fw_priv->buf = NULL;
+}
+
+#define is_fw_load_aborted(buf)	\
+	test_bit(FW_STATUS_ABORT, &(buf)->status)
+
+static LIST_HEAD(pending_fw_head);
+
+/* reboot notifier for avoid deadlock with usermode_lock */
+static int fw_shutdown_notify(struct notifier_block *unused1,
+			      unsigned long unused2, void *unused3)
+{
+	mutex_lock(&fw_lock);
+	while (!list_empty(&pending_fw_head))
+		__fw_load_abort(list_first_entry(&pending_fw_head,
+					       struct firmware_buf,
+					       pending_list));
+	mutex_unlock(&fw_lock);
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block fw_shutdown_nb = {
+	.notifier_call = fw_shutdown_notify,
+};
+
+static ssize_t 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 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_RW(timeout),
+	__ATTR_NULL
+};
+
+static void fw_dev_release(struct device *dev)
+{
+	struct firmware_priv *fw_priv = to_firmware_priv(dev);
+
+	kfree(fw_priv);
+}
+
+static int do_firmware_uevent(struct firmware_priv *fw_priv, struct kobj_uevent_env *env)
+{
+	if (add_uevent_var(env, "FIRMWARE=%s", fw_priv->buf->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 int firmware_uevent(struct device *dev, struct kobj_uevent_env *env)
+{
+	struct firmware_priv *fw_priv = to_firmware_priv(dev);
+	int err = 0;
+
+	mutex_lock(&fw_lock);
+	if (fw_priv->buf)
+		err = do_firmware_uevent(fw_priv, env);
+	mutex_unlock(&fw_lock);
+	return err;
+}
+
+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 = 0;
+
+	mutex_lock(&fw_lock);
+	if (fw_priv->buf)
+		loading = test_bit(FW_STATUS_LOADING, &fw_priv->buf->status);
+	mutex_unlock(&fw_lock);
+
+	return sprintf(buf, "%d\n", loading);
+}
+
+/* Some architectures don't have PAGE_KERNEL_RO */
+#ifndef PAGE_KERNEL_RO
+#define PAGE_KERNEL_RO PAGE_KERNEL
+#endif
+
+/* one pages buffer should be mapped/unmapped only once */
+static int fw_map_pages_buf(struct firmware_buf *buf)
+{
+	if (!buf->is_paged_buf)
+		return 0;
+
+	vunmap(buf->data);
+	buf->data = vmap(buf->pages, buf->nr_pages, 0, PAGE_KERNEL_RO);
+	if (!buf->data)
+		return -ENOMEM;
+	return 0;
+}
+
+/**
+ * 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);
+	struct firmware_buf *fw_buf;
+	ssize_t written = count;
+	int loading = simple_strtol(buf, NULL, 10);
+	int i;
+
+	mutex_lock(&fw_lock);
+	fw_buf = fw_priv->buf;
+	if (!fw_buf)
+		goto out;
+
+	switch (loading) {
+	case 1:
+		/* discarding any previous partial load */
+		if (!test_bit(FW_STATUS_DONE, &fw_buf->status)) {
+			for (i = 0; i < fw_buf->nr_pages; i++)
+				__free_page(fw_buf->pages[i]);
+			kfree(fw_buf->pages);
+			fw_buf->pages = NULL;
+			fw_buf->page_array_size = 0;
+			fw_buf->nr_pages = 0;
+			set_bit(FW_STATUS_LOADING, &fw_buf->status);
+		}
+		break;
+	case 0:
+		if (test_bit(FW_STATUS_LOADING, &fw_buf->status)) {
+			int rc;
+
+			set_bit(FW_STATUS_DONE, &fw_buf->status);
+			clear_bit(FW_STATUS_LOADING, &fw_buf->status);
+
+			/*
+			 * Several loading requests may be pending on
+			 * one same firmware buf, so let all requests
+			 * see the mapped 'buf->data' once the loading
+			 * is completed.
+			 * */
+			rc = fw_map_pages_buf(fw_buf);
+			if (rc)
+				dev_err(dev, "%s: map pages failed\n",
+					__func__);
+			else
+				rc = security_kernel_fw_from_file(NULL,
+						fw_buf->data, fw_buf->size);
+
+			/*
+			 * Same logic as fw_load_abort, only the DONE bit
+			 * is ignored and we set ABORT only on failure.
+			 */
+			list_del_init(&fw_buf->pending_list);
+			if (rc) {
+				set_bit(FW_STATUS_ABORT, &fw_buf->status);
+				written = rc;
+			}
+			complete_all(&fw_buf->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 written;
+}
+
+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_buf *buf;
+	ssize_t ret_count;
+
+	mutex_lock(&fw_lock);
+	buf = fw_priv->buf;
+	if (!buf || test_bit(FW_STATUS_DONE, &buf->status)) {
+		ret_count = -ENODEV;
+		goto out;
+	}
+	if (offset > buf->size) {
+		ret_count = 0;
+		goto out;
+	}
+	if (count > buf->size - offset)
+		count = buf->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(buf->pages[page_nr]);
+
+		memcpy(buffer, page_data + page_ofs, page_cnt);
+
+		kunmap(buf->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)
+{
+	struct firmware_buf *buf = fw_priv->buf;
+	int pages_needed = PAGE_ALIGN(min_size) >> PAGE_SHIFT;
+
+	/* If the array of pages is too small, grow it... */
+	if (buf->page_array_size < pages_needed) {
+		int new_array_size = max(pages_needed,
+					 buf->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, buf->pages,
+		       buf->page_array_size * sizeof(void *));
+		memset(&new_pages[buf->page_array_size], 0, sizeof(void *) *
+		       (new_array_size - buf->page_array_size));
+		kfree(buf->pages);
+		buf->pages = new_pages;
+		buf->page_array_size = new_array_size;
+	}
+
+	while (buf->nr_pages < pages_needed) {
+		buf->pages[buf->nr_pages] =
+			alloc_page(GFP_KERNEL | __GFP_HIGHMEM);
+
+		if (!buf->pages[buf->nr_pages]) {
+			fw_load_abort(fw_priv);
+			return -ENOMEM;
+		}
+		buf->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_buf *buf;
+	ssize_t retval;
+
+	if (!capable(CAP_SYS_RAWIO))
+		return -EPERM;
+
+	mutex_lock(&fw_lock);
+	buf = fw_priv->buf;
+	if (!buf || test_bit(FW_STATUS_DONE, &buf->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(buf->pages[page_nr]);
+
+		memcpy(page_data + page_ofs, buffer, page_cnt);
+
+		kunmap(buf->pages[page_nr]);
+		buffer += page_cnt;
+		offset += page_cnt;
+		count -= page_cnt;
+	}
+
+	buf->size = max_t(size_t, offset, buf->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 struct attribute *fw_dev_attrs[] = {
+	&dev_attr_loading.attr,
+	NULL
+};
+
+static struct bin_attribute *fw_dev_bin_attrs[] = {
+	&firmware_attr_data,
+	NULL
+};
+
+static const struct attribute_group fw_dev_attr_group = {
+	.attrs = fw_dev_attrs,
+	.bin_attrs = fw_dev_bin_attrs,
+};
+
+static const struct attribute_group *fw_dev_attr_groups[] = {
+	&fw_dev_attr_group,
+	NULL
+};
+
+static struct firmware_priv *
+fw_create_instance(struct firmware *firmware, const char *fw_name,
+		   struct device *device, unsigned int opt_flags)
+{
+	struct firmware_priv *fw_priv;
+	struct device *f_dev;
+
+	fw_priv = kzalloc(sizeof(*fw_priv), GFP_KERNEL);
+	if (!fw_priv) {
+		fw_priv = ERR_PTR(-ENOMEM);
+		goto exit;
+	}
+
+	fw_priv->nowait = !!(opt_flags & FW_OPT_NOWAIT);
+	fw_priv->fw = firmware;
+	f_dev = &fw_priv->dev;
+
+	device_initialize(f_dev);
+	dev_set_name(f_dev, "%s", fw_name);
+	f_dev->parent = device;
+	f_dev->class = &firmware_class;
+	f_dev->groups = fw_dev_attr_groups;
+exit:
+	return fw_priv;
+}
+
+/* load a firmware via user helper */
+static int _request_firmware_load(struct firmware_priv *fw_priv,
+				  unsigned int opt_flags, long timeout)
+{
+	int retval = 0;
+	struct device *f_dev = &fw_priv->dev;
+	struct firmware_buf *buf = fw_priv->buf;
+
+	/* fall back on userspace loading */
+	buf->is_paged_buf = true;
+
+	dev_set_uevent_suppress(f_dev, true);
+
+	retval = device_add(f_dev);
+	if (retval) {
+		dev_err(f_dev, "%s: device_register failed\n", __func__);
+		goto err_put_dev;
+	}
+
+	mutex_lock(&fw_lock);
+	list_add(&buf->pending_list, &pending_fw_head);
+	mutex_unlock(&fw_lock);
+
+	if (opt_flags & FW_OPT_UEVENT) {
+		buf->need_uevent = true;
+		dev_set_uevent_suppress(f_dev, false);
+		dev_dbg(f_dev, "firmware: requesting %s\n", buf->fw_id);
+		kobject_uevent(&fw_priv->dev.kobj, KOBJ_ADD);
+	} else {
+		timeout = MAX_JIFFY_OFFSET;
+	}
+
+	retval = wait_for_completion_interruptible_timeout(&buf->completion,
+			timeout);
+	if (retval == -ERESTARTSYS || !retval) {
+		mutex_lock(&fw_lock);
+		fw_load_abort(fw_priv);
+		mutex_unlock(&fw_lock);
+	} else if (retval > 0) {
+		retval = 0;
+	}
+
+	if (is_fw_load_aborted(buf))
+		retval = -EAGAIN;
+	else if (!buf->data)
+		retval = -ENOMEM;
+
+	device_del(f_dev);
+err_put_dev:
+	put_device(f_dev);
+	return retval;
+}
+
+static int fw_load_from_user_helper(struct firmware *firmware,
+				    const char *name, struct device *device,
+				    unsigned int opt_flags, long timeout)
+{
+	struct firmware_priv *fw_priv;
+
+	fw_priv = fw_create_instance(firmware, name, device, opt_flags);
+	if (IS_ERR(fw_priv))
+		return PTR_ERR(fw_priv);
+
+	fw_priv->buf = firmware->priv;
+	return _request_firmware_load(fw_priv, opt_flags, timeout);
+}
+
+#ifdef CONFIG_PM_SLEEP
+/* kill pending requests without uevent to avoid blocking suspend */
+static void kill_requests_without_uevent(void)
+{
+	struct firmware_buf *buf;
+	struct firmware_buf *next;
+
+	mutex_lock(&fw_lock);
+	list_for_each_entry_safe(buf, next, &pending_fw_head, pending_list) {
+		if (!buf->need_uevent)
+			 __fw_load_abort(buf);
+	}
+	mutex_unlock(&fw_lock);
+}
+#endif
+
+#else /* CONFIG_FW_LOADER_USER_HELPER */
+static inline int
+fw_load_from_user_helper(struct firmware *firmware, const char *name,
+			 struct device *device, unsigned int opt_flags,
+			 long timeout)
+{
+	return -ENOENT;
+}
+
+/* No abort during direct loading */
+#define is_fw_load_aborted(buf) false
+
+#ifdef CONFIG_PM_SLEEP
+static inline void kill_requests_without_uevent(void) { }
+#endif
+
+#endif /* CONFIG_FW_LOADER_USER_HELPER */
+
+
+/* wait until the shared firmware_buf becomes ready (or error) */
+static int sync_cached_firmware_buf(struct firmware_buf *buf)
+{
+	int ret = 0;
+
+	mutex_lock(&fw_lock);
+	while (!test_bit(FW_STATUS_DONE, &buf->status)) {
+		if (is_fw_load_aborted(buf)) {
+			ret = -ENOENT;
+			break;
+		}
+		mutex_unlock(&fw_lock);
+		ret = wait_for_completion_interruptible(&buf->completion);
+		mutex_lock(&fw_lock);
+	}
+	mutex_unlock(&fw_lock);
+	return ret;
+}
+
+/* prepare firmware and firmware_buf structs;
+ * return 0 if a firmware is already assigned, 1 if need to load one,
+ * or a negative error code
+ */
+static int
+_request_firmware_prepare(struct firmware **firmware_p, const char *name,
+			  struct device *device)
+{
+	struct firmware *firmware;
+	struct firmware_buf *buf;
+	int ret;
+
+	*firmware_p = firmware = kzalloc(sizeof(*firmware), GFP_KERNEL);
+	if (!firmware) {
+		dev_err(device, "%s: kmalloc(struct firmware) failed\n",
+			__func__);
+		return -ENOMEM;
+	}
+
+	if (fw_get_builtin_firmware(firmware, name)) {
+		dev_dbg(device, "firmware: using built-in firmware %s\n", name);
+		return 0; /* assigned */
+	}
+
+	ret = fw_lookup_and_allocate_buf(name, &fw_cache, &buf);
+
+	/*
+	 * bind with 'buf' now to avoid warning in failure path
+	 * of requesting firmware.
+	 */
+	firmware->priv = buf;
+
+	if (ret > 0) {
+		ret = sync_cached_firmware_buf(buf);
+		if (!ret) {
+			fw_set_page_data(buf, firmware);
+			return 0; /* assigned */
+		}
+	}
+
+	if (ret < 0)
+		return ret;
+	return 1; /* need to load */
+}
+
+static int assign_firmware_buf(struct firmware *fw, struct device *device,
+			       unsigned int opt_flags)
+{
+	struct firmware_buf *buf = fw->priv;
+
+	mutex_lock(&fw_lock);
+	if (!buf->size || is_fw_load_aborted(buf)) {
+		mutex_unlock(&fw_lock);
+		return -ENOENT;
+	}
+
+	/*
+	 * add firmware name into devres list so that we can auto cache
+	 * and uncache firmware for device.
+	 *
+	 * device may has been deleted already, but the problem
+	 * should be fixed in devres or driver core.
+	 */
+	/* don't cache firmware handled without uevent */
+	if (device && (opt_flags & FW_OPT_UEVENT))
+		fw_add_devm_name(device, buf->fw_id);
+
+	/*
+	 * After caching firmware image is started, let it piggyback
+	 * on request firmware.
+	 */
+	if (buf->fwc->state == FW_LOADER_START_CACHE) {
+		if (fw_cache_piggyback_on_request(buf->fw_id))
+			kref_get(&buf->ref);
+	}
+
+	/* pass the pages buffer to driver at the last minute */
+	fw_set_page_data(buf, fw);
+	mutex_unlock(&fw_lock);
+	return 0;
+}
+
+/* called from request_firmware() and request_firmware_work_func() */
+static int
+_request_firmware(const struct firmware **firmware_p, const char *name,
+		  struct device *device, unsigned int opt_flags)
+{
+	struct firmware *fw;
+	long timeout;
+	int ret;
+
+	if (!firmware_p)
+		return -EINVAL;
+
+	if (!name || name[0] == '\0')
+		return -EINVAL;
+
+	ret = _request_firmware_prepare(&fw, name, device);
+	if (ret <= 0) /* error or already assigned */
+		goto out;
+
+	ret = 0;
+	timeout = is_nonfree_firmware(name) ? 1 : firmware_loading_timeout();
+	if (opt_flags & FW_OPT_NOWAIT) {
+		timeout = usermodehelper_read_lock_wait(timeout);
+		if (!timeout) {
+			dev_dbg(device, "firmware: %s loading timed out\n",
+				name);
+			ret = -EBUSY;
+			goto out;
+		}
+	} else {
+		ret = usermodehelper_read_trylock();
+		if (WARN_ON(ret)) {
+			dev_err(device, "firmware: %s will not be loaded\n",
+				name);
+			goto out;
+		}
+	}
+
+	ret = fw_get_filesystem_firmware(device, fw->priv);
+	if (ret) {
+		if (!(opt_flags & FW_OPT_NO_WARN))
+			dev_warn(device,
+				 "Direct firmware load for %s failed with error %d\n",
+				 name, ret);
+		if (opt_flags & FW_OPT_USERHELPER) {
+			dev_warn(device, "Falling back to user helper\n");
+			ret = fw_load_from_user_helper(fw, name, device,
+						       opt_flags, timeout);
+		}
+	}
+
+	if (!ret)
+		ret = assign_firmware_buf(fw, device, opt_flags);
+
+	usermodehelper_read_unlock();
+
+ out:
+	if (ret < 0) {
+		release_firmware(fw);
+		fw = NULL;
+	}
+
+	*firmware_p = fw;
+	return ret;
+}
+
+/**
+ * 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.
+ *
+ *	Caller must hold the reference count of @device.
+ *
+ *	The function can be called safely inside device's suspend and
+ *	resume callback.
+ **/
+int
+request_firmware(const struct firmware **firmware_p, const char *name,
+		 struct device *device)
+{
+	int ret;
+
+	/* Need to pin this module until return */
+	__module_get(THIS_MODULE);
+	ret = _request_firmware(firmware_p, name, device,
+				FW_OPT_UEVENT | FW_OPT_FALLBACK);
+	module_put(THIS_MODULE);
+	return ret;
+}
+EXPORT_SYMBOL(request_firmware);
+
+/**
+ * request_firmware_direct: - load firmware directly without usermode helper
+ * @firmware_p: pointer to firmware image
+ * @name: name of firmware file
+ * @device: device for which firmware is being loaded
+ *
+ * This function works pretty much like request_firmware(), but this doesn't
+ * fall back to usermode helper even if the firmware couldn't be loaded
+ * directly from fs.  Hence it's useful for loading optional firmwares, which
+ * aren't always present, without extra long timeouts of udev.
+ **/
+int request_firmware_direct(const struct firmware **firmware_p,
+			    const char *name, struct device *device)
+{
+	int ret;
+
+	__module_get(THIS_MODULE);
+	ret = _request_firmware(firmware_p, name, device,
+				FW_OPT_UEVENT | FW_OPT_NO_WARN);
+	module_put(THIS_MODULE);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(request_firmware_direct);
+
+/**
+ * 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);
+	}
+}
+EXPORT_SYMBOL(release_firmware);
+
+/* 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);
+	unsigned int opt_flags;
+};
+
+static void request_firmware_work_func(struct work_struct *work)
+{
+	struct firmware_work *fw_work;
+	const struct firmware *fw;
+
+	fw_work = container_of(work, struct firmware_work, work);
+
+	_request_firmware(&fw, fw_work->name, fw_work->device,
+			  fw_work->opt_flags);
+	fw_work->cont(fw, fw_work->context);
+	put_device(fw_work->device); /* taken in request_firmware_nowait() */
+
+	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.
+ *
+ *	Caller must hold the reference count of @device.
+ *
+ *	Asynchronous variant of request_firmware() for user contexts:
+ *		- sleep for as small periods as possible since it may
+ *		increase kernel boot time of built-in device drivers
+ *		requesting firmware in their ->probe() methods, if
+ *		@gfp is GFP_KERNEL.
+ *
+ *		- can't sleep at all if @gfp is GFP_ATOMIC.
+ **/
+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->opt_flags = FW_OPT_NOWAIT | FW_OPT_FALLBACK |
+		(uevent ? FW_OPT_UEVENT : FW_OPT_USERHELPER);
+
+	if (!try_module_get(module)) {
+		kfree(fw_work);
+		return -EFAULT;
+	}
+
+	get_device(fw_work->device);
+	INIT_WORK(&fw_work->work, request_firmware_work_func);
+	schedule_work(&fw_work->work);
+	return 0;
+}
+EXPORT_SYMBOL(request_firmware_nowait);
+
+#ifdef CONFIG_PM_SLEEP
+static ASYNC_DOMAIN_EXCLUSIVE(fw_cache_domain);
+
+/**
+ * cache_firmware - cache one firmware image in kernel memory space
+ * @fw_name: the firmware image name
+ *
+ * Cache firmware in kernel memory so that drivers can use it when
+ * system isn't ready for them to request firmware image from userspace.
+ * Once it returns successfully, driver can use request_firmware or its
+ * nowait version to get the cached firmware without any interacting
+ * with userspace
+ *
+ * Return 0 if the firmware image has been cached successfully
+ * Return !0 otherwise
+ *
+ */
+static int cache_firmware(const char *fw_name)
+{
+	int ret;
+	const struct firmware *fw;
+
+	pr_debug("%s: %s\n", __func__, fw_name);
+
+	ret = request_firmware(&fw, fw_name, NULL);
+	if (!ret)
+		kfree(fw);
+
+	pr_debug("%s: %s ret=%d\n", __func__, fw_name, ret);
+
+	return ret;
+}
+
+static struct firmware_buf *fw_lookup_buf(const char *fw_name)
+{
+	struct firmware_buf *tmp;
+	struct firmware_cache *fwc = &fw_cache;
+
+	spin_lock(&fwc->lock);
+	tmp = __fw_lookup_buf(fw_name);
+	spin_unlock(&fwc->lock);
+
+	return tmp;
+}
+
+/**
+ * uncache_firmware - remove one cached firmware image
+ * @fw_name: the firmware image name
+ *
+ * Uncache one firmware image which has been cached successfully
+ * before.
+ *
+ * Return 0 if the firmware cache has been removed successfully
+ * Return !0 otherwise
+ *
+ */
+static int uncache_firmware(const char *fw_name)
+{
+	struct firmware_buf *buf;
+	struct firmware fw;
+
+	pr_debug("%s: %s\n", __func__, fw_name);
+
+	if (fw_get_builtin_firmware(&fw, fw_name))
+		return 0;
+
+	buf = fw_lookup_buf(fw_name);
+	if (buf) {
+		fw_free_buf(buf);
+		return 0;
+	}
+
+	return -EINVAL;
+}
+
+static struct fw_cache_entry *alloc_fw_cache_entry(const char *name)
+{
+	struct fw_cache_entry *fce;
+
+	fce = kzalloc(sizeof(*fce) + strlen(name) + 1, GFP_ATOMIC);
+	if (!fce)
+		goto exit;
+
+	strcpy(fce->name, name);
+exit:
+	return fce;
+}
+
+static int __fw_entry_found(const char *name)
+{
+	struct firmware_cache *fwc = &fw_cache;
+	struct fw_cache_entry *fce;
+
+	list_for_each_entry(fce, &fwc->fw_names, list) {
+		if (!strcmp(fce->name, name))
+			return 1;
+	}
+	return 0;
+}
+
+static int fw_cache_piggyback_on_request(const char *name)
+{
+	struct firmware_cache *fwc = &fw_cache;
+	struct fw_cache_entry *fce;
+	int ret = 0;
+
+	spin_lock(&fwc->name_lock);
+	if (__fw_entry_found(name))
+		goto found;
+
+	fce = alloc_fw_cache_entry(name);
+	if (fce) {
+		ret = 1;
+		list_add(&fce->list, &fwc->fw_names);
+		pr_debug("%s: fw: %s\n", __func__, name);
+	}
+found:
+	spin_unlock(&fwc->name_lock);
+	return ret;
+}
+
+static void free_fw_cache_entry(struct fw_cache_entry *fce)
+{
+	kfree(fce);
+}
+
+static void __async_dev_cache_fw_image(void *fw_entry,
+				       async_cookie_t cookie)
+{
+	struct fw_cache_entry *fce = fw_entry;
+	struct firmware_cache *fwc = &fw_cache;
+	int ret;
+
+	ret = cache_firmware(fce->name);
+	if (ret) {
+		spin_lock(&fwc->name_lock);
+		list_del(&fce->list);
+		spin_unlock(&fwc->name_lock);
+
+		free_fw_cache_entry(fce);
+	}
+}
+
+/* called with dev->devres_lock held */
+static void dev_create_fw_entry(struct device *dev, void *res,
+				void *data)
+{
+	struct fw_name_devm *fwn = res;
+	const char *fw_name = fwn->name;
+	struct list_head *head = data;
+	struct fw_cache_entry *fce;
+
+	fce = alloc_fw_cache_entry(fw_name);
+	if (fce)
+		list_add(&fce->list, head);
+}
+
+static int devm_name_match(struct device *dev, void *res,
+			   void *match_data)
+{
+	struct fw_name_devm *fwn = res;
+	return (fwn->magic == (unsigned long)match_data);
+}
+
+static void dev_cache_fw_image(struct device *dev, void *data)
+{
+	LIST_HEAD(todo);
+	struct fw_cache_entry *fce;
+	struct fw_cache_entry *fce_next;
+	struct firmware_cache *fwc = &fw_cache;
+
+	devres_for_each_res(dev, fw_name_devm_release,
+			    devm_name_match, &fw_cache,
+			    dev_create_fw_entry, &todo);
+
+	list_for_each_entry_safe(fce, fce_next, &todo, list) {
+		list_del(&fce->list);
+
+		spin_lock(&fwc->name_lock);
+		/* only one cache entry for one firmware */
+		if (!__fw_entry_found(fce->name)) {
+			list_add(&fce->list, &fwc->fw_names);
+		} else {
+			free_fw_cache_entry(fce);
+			fce = NULL;
+		}
+		spin_unlock(&fwc->name_lock);
+
+		if (fce)
+			async_schedule_domain(__async_dev_cache_fw_image,
+					      (void *)fce,
+					      &fw_cache_domain);
+	}
+}
+
+static void __device_uncache_fw_images(void)
+{
+	struct firmware_cache *fwc = &fw_cache;
+	struct fw_cache_entry *fce;
+
+	spin_lock(&fwc->name_lock);
+	while (!list_empty(&fwc->fw_names)) {
+		fce = list_entry(fwc->fw_names.next,
+				struct fw_cache_entry, list);
+		list_del(&fce->list);
+		spin_unlock(&fwc->name_lock);
+
+		uncache_firmware(fce->name);
+		free_fw_cache_entry(fce);
+
+		spin_lock(&fwc->name_lock);
+	}
+	spin_unlock(&fwc->name_lock);
+}
+
+/**
+ * device_cache_fw_images - cache devices' firmware
+ *
+ * If one device called request_firmware or its nowait version
+ * successfully before, the firmware names are recored into the
+ * device's devres link list, so device_cache_fw_images can call
+ * cache_firmware() to cache these firmwares for the device,
+ * then the device driver can load its firmwares easily at
+ * time when system is not ready to complete loading firmware.
+ */
+static void device_cache_fw_images(void)
+{
+	struct firmware_cache *fwc = &fw_cache;
+	int old_timeout;
+	DEFINE_WAIT(wait);
+
+	pr_debug("%s\n", __func__);
+
+	/* cancel uncache work */
+	cancel_delayed_work_sync(&fwc->work);
+
+	/*
+	 * use small loading timeout for caching devices' firmware
+	 * because all these firmware images have been loaded
+	 * successfully at lease once, also system is ready for
+	 * completing firmware loading now. The maximum size of
+	 * firmware in current distributions is about 2M bytes,
+	 * so 10 secs should be enough.
+	 */
+	old_timeout = loading_timeout;
+	loading_timeout = 10;
+
+	mutex_lock(&fw_lock);
+	fwc->state = FW_LOADER_START_CACHE;
+	dpm_for_each_dev(NULL, dev_cache_fw_image);
+	mutex_unlock(&fw_lock);
+
+	/* wait for completion of caching firmware for all devices */
+	async_synchronize_full_domain(&fw_cache_domain);
+
+	loading_timeout = old_timeout;
+}
+
+/**
+ * device_uncache_fw_images - uncache devices' firmware
+ *
+ * uncache all firmwares which have been cached successfully
+ * by device_uncache_fw_images earlier
+ */
+static void device_uncache_fw_images(void)
+{
+	pr_debug("%s\n", __func__);
+	__device_uncache_fw_images();
+}
+
+static void device_uncache_fw_images_work(struct work_struct *work)
+{
+	device_uncache_fw_images();
+}
+
+/**
+ * device_uncache_fw_images_delay - uncache devices firmwares
+ * @delay: number of milliseconds to delay uncache device firmwares
+ *
+ * uncache all devices's firmwares which has been cached successfully
+ * by device_cache_fw_images after @delay milliseconds.
+ */
+static void device_uncache_fw_images_delay(unsigned long delay)
+{
+	queue_delayed_work(system_power_efficient_wq, &fw_cache.work,
+			   msecs_to_jiffies(delay));
+}
+
+static int fw_pm_notify(struct notifier_block *notify_block,
+			unsigned long mode, void *unused)
+{
+	switch (mode) {
+	case PM_HIBERNATION_PREPARE:
+	case PM_SUSPEND_PREPARE:
+	case PM_RESTORE_PREPARE:
+		kill_requests_without_uevent();
+		device_cache_fw_images();
+		break;
+
+	case PM_POST_SUSPEND:
+	case PM_POST_HIBERNATION:
+	case PM_POST_RESTORE:
+		/*
+		 * In case that system sleep failed and syscore_suspend is
+		 * not called.
+		 */
+		mutex_lock(&fw_lock);
+		fw_cache.state = FW_LOADER_NO_CACHE;
+		mutex_unlock(&fw_lock);
+
+		device_uncache_fw_images_delay(10 * MSEC_PER_SEC);
+		break;
+	}
+
+	return 0;
+}
+
+/* stop caching firmware once syscore_suspend is reached */
+static int fw_suspend(void)
+{
+	fw_cache.state = FW_LOADER_NO_CACHE;
+	return 0;
+}
+
+static struct syscore_ops fw_syscore_ops = {
+	.suspend = fw_suspend,
+};
+#else
+static int fw_cache_piggyback_on_request(const char *name)
+{
+	return 0;
+}
+#endif
+
+static void __init fw_cache_init(void)
+{
+	spin_lock_init(&fw_cache.lock);
+	INIT_LIST_HEAD(&fw_cache.head);
+	fw_cache.state = FW_LOADER_NO_CACHE;
+
+#ifdef CONFIG_PM_SLEEP
+	spin_lock_init(&fw_cache.name_lock);
+	INIT_LIST_HEAD(&fw_cache.fw_names);
+
+	INIT_DELAYED_WORK(&fw_cache.work,
+			  device_uncache_fw_images_work);
+
+	fw_cache.pm_notify.notifier_call = fw_pm_notify;
+	register_pm_notifier(&fw_cache.pm_notify);
+
+	register_syscore_ops(&fw_syscore_ops);
+#endif
+}
+
+static int __init firmware_class_init(void)
+{
+	fw_cache_init();
+#ifdef CONFIG_FW_LOADER_USER_HELPER
+	register_reboot_notifier(&fw_shutdown_nb);
+	return class_register(&firmware_class);
+#else
+	return 0;
+#endif
+}
+
+static void __exit firmware_class_exit(void)
+{
+#ifdef CONFIG_PM_SLEEP
+	unregister_syscore_ops(&fw_syscore_ops);
+	unregister_pm_notifier(&fw_cache.pm_notify);
+#endif
+#ifdef CONFIG_FW_LOADER_USER_HELPER
+	unregister_reboot_notifier(&fw_shutdown_nb);
+	class_unregister(&firmware_class);
+#endif
+}
+
+fs_initcall(firmware_class_init);
+module_exit(firmware_class_exit);