boot: add support for button commands
With the relatively new button API in U-Boot, it's now much easier to
model the common usecase of mapping arbitrary actions to different
buttons during boot - for example entering fastboot mode, setting some
additional kernel cmdline arguments, or booting with a custom recovery
ramdisk, to name a few.
Historically, this functionality has been implemented in board code,
making it fixed for a given U-Boot binary and requiring the code be
duplicated and modified for every board.
Implement a generic abstraction to run an arbitrary command during boot
when a specific button is pressed. The button -> command mapping is
configured via environment variables with the following format:
button_cmd_N_name=<button label>
button_cmd_N=<command to run>
Where N is the mapping number starting from 0. For example:
button_cmd_0_name=vol_down
button_cmd_0=fastboot usb 0
This will cause the device to enter fastboot mode if volume down is held
during boot.
After we enter the cli loop the button commands are no longer valid,
this allows the buttons to additionally be used for navigating a boot
menu.
Tested-by: Svyatoslav Ryhel <clamor95@gmail.com> # Tegra30
Signed-off-by: Caleb Connolly <caleb.connolly@linaro.org>
diff --git a/boot/Kconfig b/boot/Kconfig
index 71ee416..3d7aabd 100644
--- a/boot/Kconfig
+++ b/boot/Kconfig
@@ -20,6 +20,21 @@
loaded that does not, the message 'Wrong FIT format: no timestamp'
is shown.
+config BUTTON_CMD
+ bool "Support for running a command if a button is held during boot"
+ depends on CMDLINE
+ depends on BUTTON
+ help
+ For many embedded devices it's useful to enter a special flashing mode
+ such as fastboot mode when a button is held during boot. This option
+ allows arbitrary commands to be assigned to specific buttons. These will
+ be run after "preboot" if the button is held. Configuration is done via
+ the environment variables "button_cmd_N_name" and "button_cmd_N" where n is
+ the button number (starting from 0). e.g:
+
+ "button_cmd_0_name=vol_down"
+ "button_cmd_0=fastboot usb 0"
+
menuconfig FIT
bool "Flattened Image Tree (FIT)"
select HASH