aarch32: optee: define the OP-TEE secure payload

AArch32 only platforms can boot the OP-TEE secure firmware as
a BL32 secure payload. Such configuration can be defined through
AARCH32_SP=optee.

The source files can rely on AARCH32_SP_OPTEE to condition
OP-TEE boot specific instruction sequences.

OP-TEE does not expect ARM Trusted Firmware formatted structure
as boot argument. Load sequence is expected to have already loaded
to OP-TEE boot arguments into the bl32 entrypoint info structure.

Last, AArch32 platform can only boot AArch32 OP-TEE images.

Change-Id: Ic28eec5004315fc9111051add6bb1a1d607fc815
Signed-off-by: Etienne Carriere <etienne.carriere@linaro.org>

bl2/bl2_image_load_v2.c

@@ -87,8 +87,10 @@ entry_point_info_t *bl2_load_images(void)
 	assert(bl2_to_next_bl_params->h.version >= VERSION_2);
 	assert(bl2_to_next_bl_params->head->ep_info);
 
-	/* Populate arg0 for the next BL image */
-	bl2_to_next_bl_params->head->ep_info->args.arg0 = (u_register_t)bl2_to_next_bl_params;
+	/* Populate arg0 for the next BL image if not already provided */
+	if (bl2_to_next_bl_params->head->ep_info->args.arg0 == 0)
+		bl2_to_next_bl_params->head->ep_info->args.arg0 =
+					(u_register_t)bl2_to_next_bl_params;
 
 	/* Flush the parameters to be passed to next image */
 	plat_flush_next_bl_params();

bl32/optee/optee.mk

+#
+# Copyright (c) 2016-2018, ARM Limited and Contributors. All rights reserved.
+#
+# SPDX-License-Identifier: BSD-3-Clause
+#
+# This makefile only aims at complying with ARM Trusted Firmware build process so
+# that "optee" is a valid ARM Trusted Firmware AArch32 Secure Playload identifier.
+
+ifneq ($(ARCH),aarch32)
+$(error This directory targets AArch32 support)
+endif
+
+$(eval $(call add_define,AARCH32_SP_OPTEE))
+
+$(info ARM Trusted Firmware built for OP-TEE payload support)

lib/optee/optee_utils.c

@@ -158,9 +158,12 @@ int parse_optee_header(entry_point_info_t *header_ep,
 	 *	and BL32_EXTRA2_IMAGE_ID to load pager and paged bin.
 	 */
 	if (!tee_validate_header(optee_header)) {
-		INFO("Invalid OPTEE header, legacy mode.\n");
-		/* Set legacy OPTEE runtime arch - aarch64 */
+		INFO("Invalid OPTEE header, set legacy mode.\n");
+#ifdef AARCH64
 		header_ep->args.arg0 = MODE_RW_64;
+#else
+		header_ep->args.arg0 = MODE_RW_32;
+#endif
 		return 0;
 	}
 
@@ -208,10 +211,16 @@ int parse_optee_header(entry_point_info_t *header_ep,
 	header_ep->args.arg2 = paged_image_info->image_size;
 
 	/* Set OPTEE runtime arch - aarch32/aarch64 */
-	if (optee_header->arch == 0)
+	if (optee_header->arch == 0) {
 		header_ep->args.arg0 = MODE_RW_32;
-	else
+	} else {
+#ifdef AARCH64
 		header_ep->args.arg0 = MODE_RW_64;
+#else
+		ERROR("Cannot boot an AArch64 OP-TEE\n");
+		return -1;
+#endif
+	}
 
 	return 0;
 }