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Commit 27602842 authored by Ming Lei's avatar Ming Lei Committed by Greg Kroah-Hartman
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firmware loader: introduce module parameter to customize(v4) fw search path 

This patch introduces one module parameter of 'path' in firmware_class
to support customizing firmware image search path, so that people can
use its own firmware path if the default built-in paths can't meet their
demand[1], and the typical usage is passing the below from kernel command
parameter when 'firmware_class' is built in kernel:

	firmware_class.path=$CUSTOMIZED_PATH

[1], https://lkml.org/lkml/2012/10/11/337



Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: default avatarMing Lei <ming.lei@canonical.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 60dac5e2

Documentation/firmware_class/README

+5 −0
Original line number Diff line number Diff line
@@ -22,12 +22,17 @@ 
	- 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)



 2), userspace:

 	- /sys/class/firmware/xxx/{loading,data} appear.

	- hotplug gets called with a firmware identifier in $FIRMWARE

drivers/base/firmware_class.c

+16 −1
Original line number Diff line number Diff line
@@ -269,13 +269,23 @@ static void fw_free_buf(struct firmware_buf *buf) 
}



/* direct firmware loading support */

static const char *fw_path[] = {

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)

{
@@ -317,6 +327,11 @@ static bool fw_get_filesystem_firmware(struct firmware_buf *buf) 


	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);