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Commit 2887b395 authored by Ming Lei's avatar Ming Lei Committed by Greg Kroah-Hartman
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firmware loader: introduce cache_firmware and uncache_firmware 



This patches introduce two kernel APIs of cache_firmware and
uncache_firmware, both of which take the firmware file name
as the only parameter.

So any drivers can call cache_firmware to cache the specified
firmware file into kernel memory, and can use the cached firmware
in situations which can't request firmware from user space.

Signed-off-by: default avatarMing Lei <ming.lei@canonical.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 1f2b7959

drivers/base/firmware_class.c

+92 −8
Original line number Diff line number Diff line
@@ -142,6 +142,17 @@ static struct firmware_buf *__allocate_fw_buf(const char *fw_name, 
	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)
@@ -149,14 +160,13 @@ static int fw_lookup_and_allocate_buf(const char *fw_name, 
	struct firmware_buf *tmp;



	spin_lock(&fwc->lock);

	list_for_each_entry(tmp, &fwc->head, list)

		if (!strcmp(tmp->fw_id, fw_name)) {

	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);
@@ -167,6 +177,18 @@ static int fw_lookup_and_allocate_buf(const char *fw_name, 
	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);
@@ -852,6 +874,66 @@ request_firmware_nowait( 
	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;

}



static int __init firmware_class_init(void)

{

	fw_cache_init();
@@ -869,3 +951,5 @@ module_exit(firmware_class_exit); 
EXPORT_SYMBOL(release_firmware);

EXPORT_SYMBOL(request_firmware);

EXPORT_SYMBOL(request_firmware_nowait);

EXPORT_SYMBOL_GPL(cache_firmware);

EXPORT_SYMBOL_GPL(uncache_firmware);

include/linux/firmware.h

+12 −0
Original line number Diff line number Diff line
@@ -47,6 +47,8 @@ int request_firmware_nowait( 
	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,
@@ -65,6 +67,16 @@ static inline int request_firmware_nowait( 
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