[PATCH v2 06/19] ARM: i.MX: Account for unprogrammed fuses on i.MX6 and i.MX7

[Andrey Smirnov]

On both i.MX6 and i.MX7 (also true for VFxxx) there's an additional
path that leads mask ROM to switch into serial bootloader mode. Add
code to support it.

Signed-off-by: Andrey Smirnov <andrew.smirnov at gmail.com>
---
 arch/arm/mach-imx/boot.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/arch/arm/mach-imx/boot.c b/arch/arm/mach-imx/boot.c
index dc385ceae..7c59c2181 100644
--- a/arch/arm/mach-imx/boot.c
+++ b/arch/arm/mach-imx/boot.c
@@ -228,6 +228,8 @@ void imx53_get_boot_source(enum bootsource *src, int *instance)
 #define IMX6_SRC_SBMR2	0x1c
 #define IMX6_BMOD_SERIAL	0b01
 #define IMX6_BMOD_RESERVED	0b11
+#define IMX6_BMOD_FUSES		0b00
+#define BT_FUSE_SEL		BIT(4)
 
 static bool imx6_bootsource_reserved(uint32_t sbmr2)
 {
@@ -236,7 +238,14 @@ static bool imx6_bootsource_reserved(uint32_t sbmr2)
 
 static bool imx6_bootsource_serial(uint32_t sbmr2)
 {
-	return imx53_get_bmod(sbmr2) == IMX6_BMOD_SERIAL;
+	return imx53_get_bmod(sbmr2) == IMX6_BMOD_SERIAL ||
+		/*
+		 * If boot from fuses is selected and fuses are not
+		 * programmed by setting BT_FUSE_SEL, ROM code will
+		 * fallback to serial mode
+		 */
+	       (imx53_get_bmod(sbmr2) == IMX6_BMOD_FUSES &&
+		!(sbmr2 & BT_FUSE_SEL));
 }
 
 void imx6_get_boot_source(enum bootsource *src, int *instance)
-- 
2.14.3