[PATCH v2 11/14] ARM: optee-early: add mx6_start_optee_early helper

[Sascha Hauer]

From: Marco Felsch <m.felsch at 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 at pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer at pengutronix.de>
---
 Documentation/user/optee.rst | 22 +++++++++++++++-------
 arch/arm/lib32/optee-early.c | 42 ++++++++++++++++++++++++++++++++++++++++++
 include/tee/optee.h          |  4 ++++
 3 files changed, 61 insertions(+), 7 deletions(-)

diff --git a/Documentation/user/optee.rst b/Documentation/user/optee.rst
index 2729d21d2e441c8c9ba8171544ace8f516ceefdf..88e651ddec57b50f1013aafdd8d72b8a73032740 100644
--- a/Documentation/user/optee.rst
+++ b/Documentation/user/optee.rst
@@ -19,14 +19,22 @@ 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
+``imx6q_start_optee_early()`` or ``imx6ul_start_optee_early()`` instead since it
+validates that the TZASC not bypassed and is 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.
+
+.. note:: Modification of the device tree usually makes it bigger.
+  Some spare space must be left after the end of the device tree to
+  accommodate this.
 
 Before Linux start
 ^^^^^^^^^^^^^^^^^^
diff --git a/arch/arm/lib32/optee-early.c b/arch/arm/lib32/optee-early.c
index c9959b5e41b88a1b91179546bc6e0239809cfb11..ab5d581aa6b6835e8e551762d0b2ce1ffa2b75c4 100644
--- a/arch/arm/lib32/optee-early.c
+++ b/arch/arm/lib32/optee-early.c
@@ -12,6 +12,8 @@
 #include <linux/bug.h>
 #include <debug_ll.h>
 #include <string.h>
+#include <mach/imx/imx6.h>
+#include <mach/imx/tzasc.h>
 
 static jmp_buf tee_buf;
 
@@ -41,3 +43,43 @@ int start_optee_early(void *fdt, void *tee)
 
 	return 0;
 }
+
+int imx6q_start_optee_early(void *fdt, void *tee, void *data_location,
+			    unsigned int data_location_size)
+{
+	if (imx6q_tzc380_is_bypassed())
+		panic("TZC380 is bypassed, 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);
+
+	return start_optee_early(fdt, tee);
+}
+
+int imx6ul_start_optee_early(void *fdt, void *tee, void *data_location,
+			     unsigned int data_location_size)
+{
+	if (imx6ul_tzc380_is_bypassed())
+		panic("TZC380 is bypassed, abort OP-TEE loading\n");
+
+	/* Add early non-secure TZASC region1 to pass DTO */
+	imx6ul_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);
+
+	return start_optee_early(fdt, tee);
+}
diff --git a/include/tee/optee.h b/include/tee/optee.h
index f52775dab5b40f306075bc2d302938c584a6f5ec..943dbb8fdab6a11e25fb27e3487fe6fdec59a182 100644
--- a/include/tee/optee.h
+++ b/include/tee/optee.h
@@ -54,6 +54,10 @@ static inline int optee_get_membase(u64 *membase)
 #ifdef __PBL__
 
 int start_optee_early(void* fdt, void* tee);
+int imx6q_start_optee_early(void *fdt, void *tee, void *data_location,
+			    unsigned int data_location_size);
+int imx6ul_start_optee_early(void *fdt, void *tee, void *data_location,
+			     unsigned int data_location_size);
 
 #endif /* __PBL__ */
 

-- 
2.39.5