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After we enter the cli loop the button commands are no longer valid, this allows the buttons to additionally be used for navigating a boot menu.
Signed-off-by: Caleb Connolly caleb.connolly@linaro.org --- boot/Kconfig | 14 +++++++ common/Makefile | 1 + common/button_cmd.c | 83 +++++++++++++++++++++++++++++++++++++++ common/main.c | 3 ++ doc/usage/environment.rst | 4 ++ include/button.h | 9 +++++ 6 files changed, 114 insertions(+) create mode 100644 common/button_cmd.c
diff --git a/boot/Kconfig b/boot/Kconfig index fbc49c5bca47..9580ef1cfca4 100644 --- a/boot/Kconfig +++ b/boot/Kconfig @@ -20,6 +20,20 @@ config TIMESTAMP 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" + default n + 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 diff --git a/common/Makefile b/common/Makefile index cdeadf72026c..53105a6ce12a 100644 --- a/common/Makefile +++ b/common/Makefile @@ -10,6 +10,7 @@ obj-y += main.o obj-y += exports.o obj-$(CONFIG_HUSH_PARSER) += cli_hush.o obj-$(CONFIG_AUTOBOOT) += autoboot.o +obj-$(CONFIG_BUTTON_CMD) += button_cmd.o
# # boards obj-y += board_f.o diff --git a/common/button_cmd.c b/common/button_cmd.c new file mode 100644 index 000000000000..1caea50d3f84 --- /dev/null +++ b/common/button_cmd.c @@ -0,0 +1,83 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Copyright (c) 2023 Linaro Ltd. + * Author: Caleb Connolly caleb.connolly@linaro.org + */ + +#include <button.h> +#include <command.h> +#include <env.h> +#include <log.h> +#include <vsprintf.h> + +/* Some sane limit "just in case" */ +#define MAX_BTN_CMDS 32 + +struct button_cmd { + bool pressed; + const char *btn_name; + const char *cmd; +}; + +/* + * Button commands are set via environment variables, e.g.: + * button_cmd_N_name=Volume Up + * button_cmd_N=fastboot usb 0 + * + * This function will retrieve the command for the given button N + * and populate the cmd struct with the command string and pressed + * state of the button. + * + * Returns 1 if a command was found, 0 otherwise. + */ +int get_button_cmd(int n, struct button_cmd *cmd) +{ + const char *cmd_str; + struct udevice *btn; + char buf[24]; + + snprintf(buf, sizeof(buf), "button_cmd_%d_name", n); + cmd->btn_name = env_get(buf); + if (!cmd->btn_name) + return 0; + + button_get_by_label(cmd->btn_name, &btn); + if (!btn) { + log_err("No button labelled '%s'\n", cmd->btn_name); + return 0; + } + + cmd->pressed = button_get_state(btn) == BUTTON_ON; + /* If the button isn't pressed then cmd->cmd will be unused so don't waste + * cycles reading it + */ + if (!cmd->pressed) + return 1; + + snprintf(buf, sizeof(buf), "button_cmd_%d", n); + cmd_str = env_get(buf); + if (!cmd_str) { + log_err("No command set for button '%s'\n", cmd->btn_name); + return 0; + } + + cmd->cmd = cmd_str; + + return 1; +} + +void process_button_cmds(void) +{ + struct button_cmd cmd = {0}; + int i = 0; + + while (get_button_cmd(i++, &cmd) && i < MAX_BTN_CMDS) { + if (!cmd.pressed) + continue; + + log_info("BTN '%s'> %s\n", cmd.btn_name, cmd.cmd); + run_command(cmd.cmd, CMD_FLAG_ENV); + /* Don't run commands for multiple buttons */ + return; + } +} diff --git a/common/main.c b/common/main.c index 7c70de2e59a8..717e8b7e8bd2 100644 --- a/common/main.c +++ b/common/main.c @@ -8,6 +8,7 @@
#include <common.h> #include <autoboot.h> +#include <button.h> #include <bootstage.h> #include <cli.h> #include <command.h> @@ -61,6 +62,8 @@ void main_loop(void) efi_launch_capsules(); }
+ process_button_cmds(); + s = bootdelay_process(); if (cli_process_fdt(&s)) cli_secure_boot_cmd(s); diff --git a/doc/usage/environment.rst b/doc/usage/environment.rst index c57b717caaf3..ce5a9627f025 100644 --- a/doc/usage/environment.rst +++ b/doc/usage/environment.rst @@ -190,6 +190,10 @@ bootm_size bootstopkeysha256, bootdelaykey, bootstopkey See README.autoboot
+button_cmd_0, button_cmd_0_name ... button_cmd_N, button_cmd_N_name + Used to map commands to run when a button is held during boot. + See CONFIG_BUTTON_CMD. + updatefile Location of the software update file on a TFTP server, used by the automatic software update feature. Please refer to diff --git a/include/button.h b/include/button.h index 207f4a0f4dbd..43e4ffdca1e7 100644 --- a/include/button.h +++ b/include/button.h @@ -74,4 +74,13 @@ enum button_state_t button_get_state(struct udevice *dev); */ int button_get_code(struct udevice *dev);
+#ifdef CONFIG_BUTTON_CMD +/* Process button command mappings specified in the environment, + * running the commands for buttons which are pressed + */ +void process_button_cmds(void); +#else +static inline void process_button_cmds(void) {} +#endif /* CONFIG_BUTTON_CMD */ + #endif