Add a screen showing a menu for alternative firmware

At present we allow the user to press a keypad number to boot into another
bootloader but there is no indication which one is which.

Add a new screen for this. It is entered via Ctrl-L and shows the
available bootloaders, along with the number to press for each. The
contents of the screen is rendered by the bootloader, as usual.

This is supported by two new screens, one for the keyboard UI and one for
the menu UI. Also a new function, VbExGetAltFwIdxMask(), is added to find
out what bootloaders are available.

Note: This CL combines changes for both UIs. The changes may be easier to
review separately.

CQ-DEPEND=CL:1273269
BUG=chromium:837018
BRANCH=none
TEST=FEATURES=test emerge-grunt --nodeps vboot_reference

Change-Id: Ib3227545dc677c8f9587944753e32f3b49647360
Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/1273268
Reviewed-by: Julius Werner <jwerner@chromium.org>

1 files changed, 17 insertions, 0 deletions

diff --git a/firmware/lib/vboot_ui_common.c b/firmware/lib/vboot_ui_common.c
index 727ed779..df1615d1 100644
--- a/firmware/lib/vboot_ui_common.c
+++ b/firmware/lib/vboot_ui_common.c
@@ -38,3 +38,20 @@ void vb2_run_altfw(int altfw_num)
 		VbExLegacy(altfw_num);	/* will not return if found */
 	vb2_error_beep(VB_BEEP_FAILED);
 }
+
+void vb2_error_no_altfw(void)
+{
+	VB2_DEBUG("Legacy boot is disabled\n");
+	VbExDisplayDebugInfo("WARNING: Booting legacy BIOS has not been "
+			     "enabled. Refer to the developer-mode "
+			     "documentation for details.\n");
+	vb2_error_beep(VB_BEEP_NOT_ALLOWED);
+}
+
+void vb2_try_alt_fw(int allowed, int altfw_num)
+{
+	if (allowed)
+		vb2_run_altfw(altfw_num);	/* will not return if found */
+	else
+		vb2_error_no_altfw();
+}