[PATCH] ARM: optee-early: add mx6_start_optee_early helper

[Marco Felsch <m.felsch@pengutronix.de>]

Add a i.MX6 specific helper function which covers most of the steps
usually done within the board lowlevel code. All new i.MX6 boards are
encouraged to use this helper to load OP-TEE since the helper validates
that the TZC380 is enabled and setup the TZC380 region properly.

Signed-off-by: Marco Felsch <m.felsch@pengutronix.de>
---
 Documentation/user/optee.rst | 19 ++++++++++++-------
 arch/arm/lib32/optee-early.c | 30 ++++++++++++++++++++++++++++++
 include/tee/optee.h          |  2 ++
 3 files changed, 44 insertions(+), 7 deletions(-)

diff --git a/Documentation/user/optee.rst b/Documentation/user/optee.rst
index 2729d21d2e44..451f9ad264bb 100644
--- a/Documentation/user/optee.rst
+++ b/Documentation/user/optee.rst
@@ -19,14 +19,19 @@ During the PBL
 ^^^^^^^^^^^^^^
 
 To start OP-TEE during the lowlevel initialization of your board in the ``PBL``,
-enable the ``CONFIG_PBL_OPTEE`` configuration variable. your board should then
+enable the ``CONFIG_PBL_OPTEE`` configuration variable. Your board should then
 call the function ``start_optee_early(void* tee, void* fdt)`` with a valid tee
-and FDT. Ensure that your OP-TEE is compiled with ``CFG_NS_ENTRY_ADDR`` unset,
-otherwise OP-TEE will not correctly return to barebox after startup.
-Since OP-TEE in the default configuration also modifies the device tree, don't
-pass the barebox internal device tree, instead copy it into a different memory
-location and pass it to OP-TEE afterwards.
-The modified device tree can then be passed to the main barebox start function.
+and FDT. If you're running on an i.MX6 platform your board code should call
+``int mx6_start_optee_early(void *fdt, void *tee, void *data_location, unsigned
+int data_location_size)`` instead since it validates that the TZASC is running
+and configured as expected by OP-TEE.
+
+Ensure that your OP-TEE is compiled with ``CFG_NS_ENTRY_ADDR`` unset, otherwise
+OP-TEE will not correctly return to barebox after startup. Since OP-TEE in the
+default configuration also modifies the device tree, don't pass the barebox
+internal device tree, instead copy it into a different memory location and pass
+it to OP-TEE afterwards. The modified device tree can then be passed to the
+main barebox start function.
 
 Before Linux start
 ^^^^^^^^^^^^^^^^^^
diff --git a/arch/arm/lib32/optee-early.c b/arch/arm/lib32/optee-early.c
index 735d829c99fb..a3e2892a3291 100644
--- a/arch/arm/lib32/optee-early.c
+++ b/arch/arm/lib32/optee-early.c
@@ -10,6 +10,8 @@
 #include <tee/optee.h>
 #include <debug_ll.h>
 #include <string.h>
+#include <mach/imx/imx6.h>
+#include <mach/imx/tzasc.h>
 
 static jmp_buf tee_buf;
 
@@ -37,3 +39,31 @@ int start_optee_early(void *fdt, void *tee)
 
 	return 0;
 }
+
+int mx6_start_optee_early(void *fdt, void *tee, void *data_location,
+			  unsigned int data_location_size)
+{
+	switch (__imx6_cpu_type()) {
+	case IMX6_CPUTYPE_IMX6D:
+	case IMX6_CPUTYPE_IMX6Q:
+		if (!imx6q_tzc380_is_enabled())
+			panic("TZC380 is not enabled, abort OP-TEE loading\n");
+
+		/* Add early non-secure TZASC region1 to pass DTO */
+		imx6q_tzc380_early_ns_region1();
+
+		/*
+		 * Set the OP-TEE <-> barebox exchange data location to zero.
+		 * This is optional since recent OP-TEE versions perform the
+		 * memset too.
+		 */
+		if (data_location)
+			memset(data_location, 0, data_location_size);
+
+		break;
+	default:
+		panic("Unknown CPU type\n");
+	}
+
+	return start_optee_early(fdt, tee);
+}
diff --git a/include/tee/optee.h b/include/tee/optee.h
index f52775dab5b4..19d9a20c7cdc 100644
--- a/include/tee/optee.h
+++ b/include/tee/optee.h
@@ -54,6 +54,8 @@ static inline int optee_get_membase(u64 *membase)
 #ifdef __PBL__
 
 int start_optee_early(void* fdt, void* tee);
+int mx6_start_optee_early(void *fdt, void *tee, void *data_location,
+			  unsigned int data_location_size);
 
 #endif /* __PBL__ */
 
-- 
2.39.5