[patch] 3.4.83-backport_direct_firmware_loading.patch

3.4.83-backport_direct_firmware_loading.patch (text/plain), 41.00 KB, created by Andreas Sturmlechner on 2014-03-16 14:47:40 UTC

--- linux-3.4.83/include/linux/firmware.h	2012-05-21 00:29:13.000000000 +0200
+++ linux-3.10.33/include/linux/firmware.h	2013-07-01 00:13:29.000000000 +0200
@@ -12,6 +12,9 @@
 	size_t size;
 	const u8 *data;
 	struct page **pages;
+
+	/* firmware loader private fields */
+	void *priv;
 };
 
 struct module;
@@ -44,6 +47,8 @@
 	void (*cont)(const struct firmware *fw, void *context));
 
 void release_firmware(const struct firmware *fw);
+int cache_firmware(const char *name);
+int uncache_firmware(const char *name);
 #else
 static inline int request_firmware(const struct firmware **fw,
 				   const char *name,
@@ -62,6 +67,16 @@
 static inline void release_firmware(const struct firmware *fw)
 {
 }
+
+static inline int cache_firmware(const char *name)
+{
+	return -ENOENT;
+}
+
+static inline int uncache_firmware(const char *name)
+{
+	return -EINVAL;
+}
 #endif
 
 #endif
--- linux-3.4.83/drivers/base/firmware_class.c	2012-05-21 00:29:13.000000000 +0200
+++ linux-3.10.33/drivers/base/firmware_class.c	2013-07-01 00:13:29.000000000 +0200
@@ -21,8 +21,17 @@
 #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>
 
 #define to_dev(obj) container_of(obj, struct device, kobj)
+#include <generated/utsrelease.h>
+
+#include "base.h"
 
 MODULE_AUTHOR("Manuel Estrada Sainz");
 MODULE_DESCRIPTION("Multi purpose firmware loading support");
@@ -87,23 +96,352 @@
 	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_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 firmware_priv {
+	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 *fw;
+	struct firmware_cache *fwc;
 	unsigned long status;
+	void *data;
+	size_t size;
+#ifdef CONFIG_FW_LOADER_USER_HELPER
+	bool is_paged_buf;
 	struct page **pages;
 	int nr_pages;
 	int page_array_size;
-	struct timer_list timeout;
-	struct device dev;
-	bool nowait;
+#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);
+
+	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 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;
+}
+
+static void __fw_free_buf(struct kref *ref)
+{
+	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");
+
+/* Don't inline this: 'struct kstat' is biggish */
+static noinline_for_stack long fw_file_size(struct file *file)
+{
+	struct kstat st;
+	if (vfs_getattr(file->f_path.mnt, file->f_path.dentry, &st))
+		return -1;
+	if (!S_ISREG(st.mode))
+		return -1;
+	if (st.size != (long)st.size)
+		return -1;
+	return st.size;
+}
+
+static bool fw_read_file_contents(struct file *file, struct firmware_buf *fw_buf)
+{
+	long size;
+	char *buf;
+
+	size = fw_file_size(file);
+	if (size <= 0)
+		return false;
+	buf = vmalloc(size);
+	if (!buf)
+		return false;
+	if (kernel_read(file, 0, buf, size) != size) {
+		vfree(buf);
+		return false;
+	}
+	fw_buf->data = buf;
+	fw_buf->size = size;
+	return true;
+}
+
+static bool fw_get_filesystem_firmware(struct device *device,
+				       struct firmware_buf *buf)
+{
+	int i;
+	bool success = false;
+	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;
+		success = fw_read_file_contents(file, buf);
+		fput(file);
+		if (success)
+			break;
+	}
+	__putname(path);
+
+	if (success) {
+		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 success;
+}
+
+/* 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 {
+	struct delayed_work timeout_work;
+	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);
@@ -111,11 +449,25 @@
 
 static void fw_load_abort(struct firmware_priv *fw_priv)
 {
-	set_bit(FW_STATUS_ABORT, &fw_priv->status);
-	wmb();
-	complete(&fw_priv->completion);
+	struct firmware_buf *buf = fw_priv->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;
+
+	set_bit(FW_STATUS_ABORT, &buf->status);
+	complete_all(&buf->completion);
+
+	/* avoid user action after loading abort */
+	fw_priv->buf = NULL;
 }
 
+#define is_fw_load_aborted(buf)	\
+	test_bit(FW_STATUS_ABORT, &(buf)->status)
+
 static ssize_t firmware_timeout_show(struct class *class,
 				     struct class_attribute *attr,
 				     char *buf)
@@ -156,11 +508,7 @@
 static void fw_dev_release(struct device *dev)
 {
 	struct firmware_priv *fw_priv = to_firmware_priv(dev);
-	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);
@@ -170,7 +518,7 @@
 {
 	struct firmware_priv *fw_priv = to_firmware_priv(dev);
 
-	if (add_uevent_var(env, "FIRMWARE=%s", fw_priv->fw_id))
+	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;
@@ -191,26 +539,35 @@
 				     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);
+	int loading = 0;
 
-	return sprintf(buf, "%d\n", loading);
-}
+	mutex_lock(&fw_lock);
+	if (fw_priv->buf)
+		loading = test_bit(FW_STATUS_LOADING, &fw_priv->buf->status);
+	mutex_unlock(&fw_lock);
 
-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);
-	}
+	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;
+
+	if (buf->data)
+		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
@@ -229,45 +586,41 @@
 				      const char *buf, size_t count)
 {
 	struct firmware_priv *fw_priv = to_firmware_priv(dev);
+	struct firmware_buf *fw_buf;
 	int loading = simple_strtol(buf, NULL, 10);
 	int i;
 
 	mutex_lock(&fw_lock);
-
-	if (!fw_priv->fw)
+	fw_buf = fw_priv->buf;
+	if (!fw_buf)
 		goto out;
 
 	switch (loading) {
 	case 1:
-		firmware_free_data(fw_priv->fw);
-		memset(fw_priv->fw, 0, sizeof(struct firmware));
-		/* If the pages are not owned by 'struct firmware' */
-		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);
+		/* 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_priv->status)) {
-			vunmap(fw_priv->fw->data);
-			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;
-			}
-			/* Pages are now owned by 'struct firmware' */
-			fw_priv->fw->pages = fw_priv->pages;
-			fw_priv->pages = NULL;
-
-			fw_priv->page_array_size = 0;
-			fw_priv->nr_pages = 0;
-			complete(&fw_priv->completion);
-			clear_bit(FW_STATUS_LOADING, &fw_priv->status);
+		if (test_bit(FW_STATUS_LOADING, &fw_buf->status)) {
+			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.
+			 * */
+			fw_map_pages_buf(fw_buf);
+			complete_all(&fw_buf->completion);
 			break;
 		}
 		/* fallthrough */
@@ -275,7 +628,6 @@
 		dev_err(dev, "%s: unexpected value (%d)\n", __func__, loading);
 		/* fallthrough */
 	case -1:
-	err:
 		fw_load_abort(fw_priv);
 		break;
 	}
@@ -290,23 +642,23 @@
 				  struct bin_attribute *bin_attr,
 				  char *buffer, loff_t offset, size_t count)
 {
 	struct device *dev = to_dev(kobj);
 	struct firmware_priv *fw_priv = to_firmware_priv(dev);
-	struct firmware *fw;
+	struct firmware_buf *buf;
 	ssize_t ret_count;
 
 	mutex_lock(&fw_lock);
-	fw = fw_priv->fw;
-	if (!fw || test_bit(FW_STATUS_DONE, &fw_priv->status)) {
+	buf = fw_priv->buf;
+	if (!buf || test_bit(FW_STATUS_DONE, &buf->status)) {
 		ret_count = -ENODEV;
 		goto out;
 	}
-	if (offset > fw->size) {
+	if (offset > buf->size) {
 		ret_count = 0;
 		goto out;
 	}
-	if (count > fw->size - offset)
-		count = fw->size - offset;
+	if (count > buf->size - offset)
+		count = buf->size - offset;
 
 	ret_count = count;
 
@@ -316,11 +668,11 @@
 		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]);
+		page_data = kmap(buf->pages[page_nr]);
 
 		memcpy(buffer, page_data + page_ofs, page_cnt);
 
-		kunmap(fw_priv->pages[page_nr]);
+		kunmap(buf->pages[page_nr]);
 		buffer += page_cnt;
 		offset += page_cnt;
 		count -= page_cnt;
@@ -332,12 +684,13 @@
 
 static int fw_realloc_buffer(struct firmware_priv *fw_priv, int min_size)
 {
+	struct firmware_buf *buf = fw_priv->buf;
 	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) {
+	if (buf->page_array_size < pages_needed) {
 		int new_array_size = max(pages_needed,
-					 fw_priv->page_array_size * 2);
+					 buf->page_array_size * 2);
 		struct page **new_pages;
 
 		new_pages = kmalloc(new_array_size * sizeof(void *),
@@ -346,24 +699,24 @@
 			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;
+		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 (fw_priv->nr_pages < pages_needed) {
-		fw_priv->pages[fw_priv->nr_pages] =
+	while (buf->nr_pages < pages_needed) {
+		buf->pages[buf->nr_pages] =
 			alloc_page(GFP_KERNEL | __GFP_HIGHMEM);
 
-		if (!fw_priv->pages[fw_priv->nr_pages]) {
+		if (!buf->pages[buf->nr_pages]) {
 			fw_load_abort(fw_priv);
 			return -ENOMEM;
 		}
-		fw_priv->nr_pages++;
+		buf->nr_pages++;
 	}
 	return 0;
 }
@@ -384,20 +737,21 @@
 				   struct bin_attribute *bin_attr,
 				   char *buffer, loff_t offset, size_t count)
 {
 	struct device *dev = to_dev(kobj);
 	struct firmware_priv *fw_priv = to_firmware_priv(dev);
-	struct firmware *fw;
+	struct firmware_buf *buf;
 	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)) {
+	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;
@@ -410,17 +764,17 @@
 		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]);
+		page_data = kmap(buf->pages[page_nr]);
 
 		memcpy(page_data + page_ofs, buffer, page_cnt);
 
-		kunmap(fw_priv->pages[page_nr]);
+		kunmap(buf->pages[page_nr]);
 		buffer += page_cnt;
 		offset += page_cnt;
 		count -= page_cnt;
 	}
 
-	fw->size = max_t(size_t, offset, fw->size);
+	buf->size = max_t(size_t, offset, buf->size);
 out:
 	mutex_unlock(&fw_lock);
 	return retval;
@@ -433,11 +787,14 @@
 	.write = firmware_data_write,
 };
 
-static void firmware_class_timeout(u_long data)
+static void firmware_class_timeout_work(struct work_struct *work)
 {
-	struct firmware_priv *fw_priv = (struct firmware_priv *) data;
+	struct firmware_priv *fw_priv = container_of(work,
+			struct firmware_priv, timeout_work.work);
 
+	mutex_lock(&fw_lock);
 	fw_load_abort(fw_priv);
+	mutex_unlock(&fw_lock);
 }
 
 static struct firmware_priv *
@@ -447,70 +804,38 @@
 	struct firmware_priv *fw_priv;
 	struct device *f_dev;
 
-	fw_priv = kzalloc(sizeof(*fw_priv) + strlen(fw_name) + 1 , GFP_KERNEL);
+	fw_priv = kzalloc(sizeof(*fw_priv), GFP_KERNEL);
 	if (!fw_priv) {
 		dev_err(device, "%s: kmalloc failed\n", __func__);
-		return ERR_PTR(-ENOMEM);
+		fw_priv = ERR_PTR(-ENOMEM);
+		goto exit;
 	}
 
-	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);
+	fw_priv->fw = firmware;
+	INIT_DELAYED_WORK(&fw_priv->timeout_work,
+		firmware_class_timeout_work);
 
 	f_dev = &fw_priv->dev;
 
 	device_initialize(f_dev);
-	dev_set_name(f_dev, "%s", dev_name(device));
+	dev_set_name(f_dev, "%s", fw_name);
 	f_dev->parent = device;
 	f_dev->class = &firmware_class;
-
+exit:
 	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;
-}
-
+/* load a firmware via user helper */
 static int _request_firmware_load(struct firmware_priv *fw_priv, bool uevent,
 				  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);
 
@@ -537,24 +862,16 @@
 
 	if (uevent) {
 		dev_set_uevent_suppress(f_dev, false);
-		dev_dbg(f_dev, "firmware: requesting %s\n", fw_priv->fw_id);
+		dev_dbg(f_dev, "firmware: requesting %s\n", buf->fw_id);
 		if (timeout != MAX_SCHEDULE_TIMEOUT)
-			mod_timer(&fw_priv->timeout,
-				  round_jiffies_up(jiffies + timeout));
+			schedule_delayed_work(&fw_priv->timeout_work, timeout);
 
 		kobject_uevent(&fw_priv->dev.kobj, KOBJ_ADD);
 	}
 
-	wait_for_completion(&fw_priv->completion);
+	wait_for_completion(&buf->completion);
 
-	set_bit(FW_STATUS_DONE, &fw_priv->status);
-	del_timer_sync(&fw_priv->timeout);
-
-	mutex_lock(&fw_lock);
-	if (!fw_priv->fw->size || test_bit(FW_STATUS_ABORT, &fw_priv->status))
-		retval = -ENOENT;
-	fw_priv->fw = NULL;
-	mutex_unlock(&fw_lock);
+	cancel_delayed_work_sync(&fw_priv->timeout_work);
 
 	device_remove_file(f_dev, &dev_attr_loading);
 err_del_bin_attr:
@@ -566,6 +883,186 @@
 	return retval;
 }
 
+static int fw_load_from_user_helper(struct firmware *firmware,
+				    const char *name, struct device *device,
+				    bool uevent, bool nowait, long timeout)
+{
+	struct firmware_priv *fw_priv;
+
+	fw_priv = fw_create_instance(firmware, name, device, uevent, nowait);
+	if (IS_ERR(fw_priv))
+		return PTR_ERR(fw_priv);
+
+	fw_priv->buf = firmware->priv;
+	return _request_firmware_load(fw_priv, uevent, timeout);
+}
+#else /* CONFIG_FW_LOADER_USER_HELPER */
+static inline int
+fw_load_from_user_helper(struct firmware *firmware, const char *name,
+			 struct device *device, bool uevent, bool nowait,
+			 long timeout)
+{
+	return -ENOENT;
+}
+
+/* No abort during direct loading */
+#define is_fw_load_aborted(buf) false
+
+#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);
+		wait_for_completion(&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)
+{
+	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.
+	 */
+	if (device)
+		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, bool uevent, bool nowait)
+{
+	struct firmware *fw;
+	long timeout;
+	int ret;
+
+	if (!firmware_p)
+		return -EINVAL;
+
+	ret = _request_firmware_prepare(&fw, name, device);
+	if (ret <= 0) /* error or already assigned */
+		goto out;
+
+	ret = 0;
+	timeout = firmware_loading_timeout();
+	if (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;
+		}
+	}
+
+	if (!fw_get_filesystem_firmware(device, fw->priv))
+		ret = fw_load_from_user_helper(fw, name, device,
+					       uevent, nowait, timeout);
+	if (!ret)
+		ret = assign_firmware_buf(fw, device);
+
+	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
@@ -580,31 +1077,17 @@
  *      @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)
 {
-	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;
+	return _request_firmware(firmware_p, name, device, true, false);
 }
 
 /**
@@ -635,32 +1118,13 @@
 {
 	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:
+	_request_firmware(&fw, fw_work->name, fw_work->device,
+			  fw_work->uevent, true);
 	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);
@@ -679,9 +1143,15 @@
  * @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.
+ *	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(
@@ -707,19 +1177,371 @@
 		return -EFAULT;
 	}
 
+	get_device(fw_work->device);
 	INIT_WORK(&fw_work->work, request_firmware_work_func);
 	schedule_work(&fw_work->work);
 	return 0;
 }
 
+/**
+ * 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
+ *
+ */
+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;
+}
+
+/**
+ * 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
+ *
+ */
+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;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static ASYNC_DOMAIN_EXCLUSIVE(fw_cache_domain);
+
+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)
+{
+	schedule_delayed_work(&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:
+		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
 	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
 	class_unregister(&firmware_class);
+#endif
 }
 
 fs_initcall(firmware_class_init);
@@ -728,3 +1550,5 @@
 EXPORT_SYMBOL(release_firmware);
 EXPORT_SYMBOL(request_firmware);
 EXPORT_SYMBOL(request_firmware_nowait);
+EXPORT_SYMBOL_GPL(cache_firmware);
+EXPORT_SYMBOL_GPL(uncache_firmware);
diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig
index c8b4539..07abd9d 100644
--- a/drivers/base/Kconfig
+++ b/drivers/base/Kconfig
@@ -145,6 +145,17 @@ config EXTRA_FIRMWARE_DIR
 	  this option you can point it elsewhere, such as /lib/firmware/ or
 	  some other directory containing the firmware files.
 
+config FW_LOADER_USER_HELPER
+	bool "Fallback user-helper invocation for firmware loading"
+	depends on FW_LOADER
+	default y
+	help
+	  This option enables / disables the invocation of user-helper
+	  (e.g. udev) for loading firmware files as a fallback after the
+	  direct file loading in kernel fails.  The user-mode helper is
+	  no longer required unless you have a special firmware file that
+	  resides in a non-standard path.
+
 config DEBUG_DRIVER
 	bool "Driver Core verbose debug messages"
 	depends on DEBUG_KERNEL

--- linux-3.4.83/firmware_class/README	2012-05-21 00:29:13.000000000 +0200
+++ linux-3.10.33/Documentation/firmware_class/README	2013-07-01 00:13:29.000000000 +0200
@@ -18,32 +18,45 @@
  High level behavior (mixed):
  ============================
 
- kernel(driver): calls request_firmware(&fw_entry, $FIRMWARE, device)
+ 1), kernel(driver):
+	- calls request_firmware(&fw_entry, $FIRMWARE, device)
+	- kernel searchs the fimware image with name $FIRMWARE directly
+	in the below search path of root filesystem:
+		User customized search path by module parameter 'path'[1]
+		"/lib/firmware/updates/" UTS_RELEASE,
+		"/lib/firmware/updates",
+		"/lib/firmware/" UTS_RELEASE,
+		"/lib/firmware"
+	- If found, goto 7), else goto 2)
+
+	[1], the 'path' is a string parameter which length should be less
+	than 256, user should pass 'firmware_class.path=$CUSTOMIZED_PATH'
+	if firmware_class is built in kernel(the general situation)
 
- userspace:
+ 2), userspace:
  	- /sys/class/firmware/xxx/{loading,data} appear.
 	- hotplug gets called with a firmware identifier in $FIRMWARE
 	  and the usual hotplug environment.
 		- hotplug: echo 1 > /sys/class/firmware/xxx/loading
 
- kernel: Discard any previous partial load.
+ 3), kernel: Discard any previous partial load.
 
- userspace:
+ 4), userspace:
 		- hotplug: cat appropriate_firmware_image > \
 					/sys/class/firmware/xxx/data
 
- kernel: grows a buffer in PAGE_SIZE increments to hold the image as it
+ 5), kernel: grows a buffer in PAGE_SIZE increments to hold the image as it
 	 comes in.
 
- userspace:
+ 6), userspace:
 		- hotplug: echo 0 > /sys/class/firmware/xxx/loading
 
- kernel: request_firmware() returns and the driver has the firmware
+ 7), kernel: request_firmware() returns and the driver has the firmware
 	 image in fw_entry->{data,size}. If something went wrong
 	 request_firmware() returns non-zero and fw_entry is set to
 	 NULL.
 
- kernel(driver): Driver code calls release_firmware(fw_entry) releasing
+ 8), kernel(driver): Driver code calls release_firmware(fw_entry) releasing
 		 the firmware image and any related resource.
 
  High level behavior (driver code):
@@ -106,3 +119,10 @@
    on the setup, so I think that the choice on what firmware to make
    persistent should be left to userspace.
 
+ about firmware cache:
+ --------------------
+ After firmware cache mechanism is introduced during system sleep,
+ request_firmware can be called safely inside device's suspend and
+ resume callback, and callers need't cache the firmware by
+ themselves any more for dealing with firmware loss during system
+ resume.