libsp: Add SP messaging layer

Add SP messaging layer on top of FF-A's direct messaging functions.

Change-Id: I70f053c17f20bdb25b6f86a26d185fb3143fcc0d
Signed-off-by: Imre Kis <imre.kis@arm.com>
diff --git a/components/messaging/ffa/libsp/tests.cmake b/components/messaging/ffa/libsp/tests.cmake
index 1658033..092acef 100644
--- a/components/messaging/ffa/libsp/tests.cmake
+++ b/components/messaging/ffa/libsp/tests.cmake
@@ -126,3 +126,16 @@
 	COMPILE_DEFINITIONS
 		-DARM64
 )
+
+unit_test_add_suite(
+	NAME libsp_sp_messaging
+	SOURCES
+		${CMAKE_CURRENT_LIST_DIR}/test/test_sp_messaging.cpp
+		${CMAKE_CURRENT_LIST_DIR}/test/mock_ffa_api.cpp
+		${CMAKE_CURRENT_LIST_DIR}/sp_messaging.c
+	INCLUDE_DIRECTORIES
+		${CMAKE_CURRENT_LIST_DIR}/include/
+		${UNIT_TEST_PROJECT_PATH}/components/common/utils/include
+	COMPILE_DEFINITIONS
+		-DARM64
+)
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