firmware: Add CONFIG_EXTRA_FIRMWARE option
This allows arbitrary firmware files to be included in the static kernel
where the firmware loader can find them without requiring userspace to
be alive.
(Updated and CONFIG_EXTRA_FIRMWARE_DIR added with lots of help from
Johannes Berg).
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig
index d7da109..13cfcb4 100644
--- a/drivers/base/Kconfig
+++ b/drivers/base/Kconfig
@@ -34,6 +34,45 @@
require userspace firmware loading support, but a module built outside
the kernel tree does.
+config EXTRA_FIRMWARE
+ string "External firmware blobs to build into the kernel binary"
+ depends on FW_LOADER
+ help
+ This option allows firmware to be built into the kernel, for the
+ cases where the user either cannot or doesn't want to provide it from
+ userspace at runtime (for example, when the firmware in question is
+ required for accessing the boot device, and the user doesn't want to
+ use an initrd).
+
+ This option is a string, and takes the (space-separated) names of the
+ firmware files -- the same names which appear in MODULE_FIRMWARE()
+ and request_firmware() in the source. These files should exist under
+ the directory specified by the EXTRA_FIRMWARE_DIR option, which is
+ by default the firmware/ subdirectory of the kernel source tree.
+
+ So, for example, you might set CONFIG_EXTRA_FIRMWARE="usb8388.bin",
+ copy the usb8388.bin file into the firmware/ directory, and build the
+ kernel. Then any request_firmware("usb8388.bin") will be
+ satisfied internally without needing to call out to userspace.
+
+ WARNING: If you include additional firmware files into your binary
+ kernel image which are not available under the terms of the GPL,
+ then it may be a violation of the GPL to distribute the resulting
+ image -- since it combines both GPL and non-GPL work. You should
+ consult a lawyer of your own before distributing such an image.
+
+config EXTRA_FIRMWARE_DIR
+ string "Firmware blobs root directory"
+ depends on EXTRA_FIRMWARE != ""
+ default "firmware"
+ help
+ This option controls the directory in which the kernel build system
+ looks for the firmware files listed in the EXTRA_FIRMWARE option.
+ The default is the firmware/ directory in the kernel source tree,
+ but by changing this option you can point it elsewhere, such as
+ the /lib/firmware/ directory or another separate directory
+ containing firmware files.
+
config DEBUG_DRIVER
bool "Driver Core verbose debug messages"
depends on DEBUG_KERNEL