[PATCH v2] console: add new CONFIG_CONSOLE_DISABLE_INPUT option

[Ahmad Fatoum]

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,
-- 
2.33.0