[PATCH v2] console: add new CONFIG_CONSOLE_DISABLE_INPUT option

[Christian Melki]

Works as expected on top of 2021.08.

Tested-by: Christian Melki <christian.melki at t2data.com>

On 9/15/21 2:36 PM, Ahmad Fatoum wrote:
> From: Rouven Czerwinski <r.czerwinski at pengutronix.de>
> 
> Add CONFIG_CONSOLE_DISABLE_INPUT to initialize the consoles without
> input support, making default bootup effectively non-interactive.
> 
> Signed-off-by: Rouven Czerwinski <r.czerwinski at pengutronix.de>
> Signed-off-by: Ahmad Fatoum <a.fatoum at pengutronix.de>
> ---
> v1 is <20201013075925.2984-1-r.czerwinski at pengutronix.de>
> v1 -> v2:
>    - Make it the default for CONSOLE_NONE. This allows skipping
>      count down there early.
>    - rename write-only to disable input. This is arguably clearer
>    - allow re-enabling input on a per console basis. This way
>      e.g. a gpio-key with limited function can be reenabled,
>      but all other consoles have input disabled by default.
>    - add new CONSOLE_STDIOE to make the three bits easier to
>      write as a group.
> ---
>   common/Kconfig          | 11 +++++++++++
>   common/console.c        | 12 +++++++-----
>   common/console_simple.c |  5 ++++-
>   common/startup.c        |  5 +++++
>   include/console.h       |  2 ++
>   5 files changed, 29 insertions(+), 6 deletions(-)
> 
> diff --git a/common/Kconfig b/common/Kconfig
> index a9feae2ae866..9ae9238f88dc 100644
> --- a/common/Kconfig
> +++ b/common/Kconfig
> @@ -812,6 +812,17 @@ config CONSOLE_ALLOW_COLOR
>   	  compile time default for colored console output. After boot it
>   	  can be controlled using global.allow_color.
>   
> +config CONSOLE_DISABLE_INPUT
> +	prompt "Disable input on all consoles by default (non-interactive)"
> +	def_bool CONSOLE_NONE
> +	help
> +	  If enabled, all consoles are initially configured to not accept any input,
> +	  making the consoles effectively non-interactive.
> +	  The active device parameter can be used to override this on a per-console
> +	  basis.
> +	  CAUTION: this will also disable input devices by default, since they are
> +	  registered as consoles.
> +
>   config PBL_CONSOLE
>   	depends on PBL_IMAGE
>   	depends on !CONSOLE_NONE
> diff --git a/common/console.c b/common/console.c
> index ad1a6aaab2a0..0368c72d0b10 100644
> --- a/common/console.c
> +++ b/common/console.c
> @@ -328,7 +328,7 @@ int console_register(struct console_device *newcdev)
>   		return of_platform_populate(serdev_node, NULL, dev);
>   
>   	if (newcdev->dev && of_device_is_stdout_path(newcdev->dev, &baudrate)) {
> -		activate = 1;
> +		activate = CONSOLE_STDIOE;
>   		console_set_stdoutpath(newcdev, baudrate);
>   	}
>   
> @@ -349,16 +349,18 @@ int console_register(struct console_device *newcdev)
>   
>   	if (IS_ENABLED(CONFIG_CONSOLE_ACTIVATE_FIRST)) {
>   		if (list_empty(&console_list))
> -			activate = 1;
> +			activate = CONSOLE_STDIOE;
>   	} else if (IS_ENABLED(CONFIG_CONSOLE_ACTIVATE_ALL)) {
> -		activate = 1;
> +		activate = CONSOLE_STDIOE;
>   	}
>   
>   	list_add_tail(&newcdev->list, &console_list);
>   
> +	if (IS_ENABLED(CONFIG_CONSOLE_DISABLE_INPUT))
> +		activate &= ~CONSOLE_STDIN;
> +
>   	if (activate)
> -		console_set_active(newcdev, CONSOLE_STDIN |
> -				CONSOLE_STDOUT | CONSOLE_STDERR);
> +		console_set_active(newcdev, activate);
>   
>   	/* expose console as device in fs */
>   	newcdev->devfs.name = basprintf("%s%d", newcdev->class_dev.name,
> diff --git a/common/console_simple.c b/common/console_simple.c
> index 42224842c5ea..3b95570e5e76 100644
> --- a/common/console_simple.c
> +++ b/common/console_simple.c
> @@ -92,7 +92,10 @@ int console_register(struct console_device *newcdev)
>   		newcdev->setbrg(newcdev, newcdev->baudrate);
>   	}
>   
> -	newcdev->f_active = CONSOLE_STDIN | CONSOLE_STDOUT | CONSOLE_STDERR;
> +	newcdev->f_active = CONSOLE_STDIOE;
> +
> +	if (IS_ENABLED(CONFIG_CONSOLE_DISABLE_INPUT))
> +		newcdev->f_active = ~CONSOLE_STDIN;
>   
>   	barebox_banner();
>   
> diff --git a/common/startup.c b/common/startup.c
> index d170cb8a7c5a..0c7033f38186 100644
> --- a/common/startup.c
> +++ b/common/startup.c
> @@ -241,6 +241,11 @@ enum autoboot_state do_autoboot_countdown(void)
>   	if (autoboot_state != AUTOBOOT_UNKNOWN)
>   		return autoboot_state;
>   
> +	if (IS_ENABLED(CONFIG_CONSOLE_DISABLE_INPUT)) {
> +		printf("\nNon-interactive console, booting system\n");
> +		return autoboot_state = AUTOBOOT_BOOT;
> +	}
> +
>   	if (global_autoboot_state != AUTOBOOT_COUNTDOWN)
>   		return global_autoboot_state;
>   
> diff --git a/include/console.h b/include/console.h
> index a71d0da42ed0..5d5783ca6668 100644
> --- a/include/console.h
> +++ b/include/console.h
> @@ -18,6 +18,8 @@
>   #define CONSOLE_STDOUT          (1 << 1)
>   #define CONSOLE_STDERR          (1 << 2)
>   
> +#define CONSOLE_STDIOE          (CONSOLE_STDIN | CONSOLE_STDOUT | CONSOLE_STDERR)
> +
>   enum console_mode {
>   	CONSOLE_MODE_NORMAL,
>   	CONSOLE_MODE_RS485,
>