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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: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Ming Lei 2012-11-03 17:47:58 +08:00 committed by Greg Kroah-Hartman
parent 60dac5e284
commit 2760284206
2 changed files with 21 additions and 1 deletions
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5
Documentation/firmware_class/README
View File

@ -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

17
drivers/base/firmware_class.c
View File

@ -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);