vboot2: provide config option to clear dev mode state on recovery

On embedded devices with limited input capabilities it is necessary to
clear the developer mode condition when entering recovery. The new
configuration option will enable such behavior using the new vboot2
flag.

CQ-DEPEND=CL:261630
BRANCH=storm
BUG=chrome-os-partner:36059
TEST=with the rest of the patches applies observed desired behavior on
     SP5

Change-Id: I99c3d1330bea9980a2af3b9fd99e29ab96f2cf07
Signed-off-by: Patrick Georgi <pgeorgi@chromium.org>
Original-Commit-Id: 4c0a6315d6b4ede8d43e736ee6c82f1023f4716d
Original-Change-Id: I8e4a521e574b53a670daf692f7b45dc21635f272
Original-Signed-off-by: Vadim Bendebury <vbendeb@chromium.org>
Original-Reviewed-on: https://chromium-review.googlesource.com/261620
Original-Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/9878
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>

src/vendorcode/google/chromeos/vboot2/Kconfig

@@ -41,3 +41,12 @@ config VBOOT_ROMSTAGE_INDEX
 	help
 	  This is the index of the romstage component in the verified
 	  firmware block.
+
+config VBOOT_DISABLE_DEV_ON_RECOVERY
+	bool "Disable dev mode on recovery requests"
+	default n
+	depends on VBOOT2_VERIFY_FIRMWARE
+	help
+	  When this option is enabled, the Chrome OS device leaves the
+	  developer mode as soon as recovery request is detected. This is
+	  handy on embedded devices with limited input capabilities.

src/vendorcode/google/chromeos/vboot2/verstage.c

@@ -247,6 +247,8 @@ void verstage_main(void)
 	if (get_recovery_mode_switch()) {
 		clear_recovery_mode_switch();
 		ctx.flags |= VB2_CONTEXT_FORCE_RECOVERY_MODE;
+		if (IS_ENABLED(CONFIG_VBOOT_DISABLE_DEV_ON_RECOVERY))
+			ctx.flags |= VB2_DISABLE_DEVELOPER_MODE;
 	}
 
 	if (IS_ENABLED(CONFIG_WIPEOUT_SUPPORTED) && get_wipeout_mode_switch())