[PATCH v2 12/14] ARM: i.MX: tqma6ulx: fix barebox chainloading with OP-TEE enabled

[Sascha Hauer]

When barebox starts we have to guess if we have to start OP-TEE or not.
The current detection works by checking if the first stage passed us a
device tree pointer. This is not robust and might have security issues
[1], so replace that with the check with imx6_can_access_tzasc(). If we
can access the TZASC then we are the first stage and configure it and
start OP-TEE, otherwise assume that we are chainloaded and continue
without starting OP-TEE.

Chainloading barebox with OP-TEE enabled contained several bugs, so it
never actually worked. This patch fixes them.

[1] https://lore.kernel.org/70b41f3b-4329-48f7-827f-1924e002ab04@pengutronix.de

Reviewed-by: Marco Felsch <m.felsch at pengutronix.de>
Reviewed-by: Ahmad Fatoum <a.fatoum at pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer at pengutronix.de>
---
 arch/arm/boards/tqma6ulx/lowlevel.c | 22 +++++++++-------------
 1 file changed, 9 insertions(+), 13 deletions(-)

diff --git a/arch/arm/boards/tqma6ulx/lowlevel.c b/arch/arm/boards/tqma6ulx/lowlevel.c
index 5fd997d2ec7e79c7319237a4ae52216e584ba5cd..da67e67537167096477de2b905ee5c42c653c3af 100644
--- a/arch/arm/boards/tqma6ulx/lowlevel.c
+++ b/arch/arm/boards/tqma6ulx/lowlevel.c
@@ -16,6 +16,8 @@
 #include <pbl/i2c.h>
 #include <boards/tq/tq_eeprom.h>
 #include <tee/optee.h>
+#include <mach/imx/tzasc.h>
+#include <tee/optee.h>
 
 #include "tqma6ulx.h"
 
@@ -66,7 +68,7 @@ static void *read_eeprom(void)
 	return fdt;
 }
 
-static void noinline start_mba6ulx(u32 r0)
+static void noinline start_mba6ulx(void)
 {
 	void *fdt;
 	int tee_size;
@@ -76,21 +78,15 @@ static void noinline start_mba6ulx(u32 r0)
 
 	fdt = read_eeprom();
 
-	/* Enable normal/secure r/w for TZC380 region0 */
-	writel(0xf0000000, 0x021D0108);
-
 	/*
-	 * Chainloading barebox will pass a device tree within the RAM in r0,
-	 * skip OP-TEE early loading in this case
+	 * Skip loading barebox when we are chainloaded. We can detect that by detecting
+	 * if we can access the TZASC.
 	 */
-	if (IS_ENABLED(CONFIG_FIRMWARE_TQMA6UL_OPTEE) &&
-	    !(r0 > MX6_MMDC_P0_BASE_ADDR &&
-	      r0 < MX6_MMDC_P0_BASE_ADDR + SZ_256M)) {
-		get_builtin_firmware(mba6ul_optee_bin, &tee, &tee_size);
+	if (IS_ENABLED(CONFIG_FIRMWARE_TQMA6UL_OPTEE) && imx6_can_access_tzasc()) {
 
-		memset((void *)OPTEE_OVERLAY_LOCATION, 0, 0x1000);
+		get_builtin_firmware(mba6ul_optee_bin, &tee, &tee_size);
 
-		start_optee_early(NULL, tee);
+		imx6ul_start_optee_early(NULL, tee, (void *)OPTEE_OVERLAY_LOCATION, 0x1000);
 	}
 
 	imx6ul_barebox_entry(fdt);
@@ -112,5 +108,5 @@ ENTRY_FUNCTION(start_imx6ul_mba6ulx, r0, r1, r2)
 	setup_c();
 	barrier();
 
-	start_mba6ulx(r0);
+	start_mba6ulx();
 }

-- 
2.39.5