Add generic RPC layer

Adds generic RPC caller and endpoint. This is the base for specialized
RPC communication using e.g. FF-A messaging. The protocol description
is implemented in two flavours: packed C structures and protobuf.

Change-Id: I17f450b7272bd4008fc20fe8f716a253f6754000
Signed-off-by: Julian Hall <julian.hall@arm.com>
diff --git a/components/rpc/common/interface/component.cmake b/components/rpc/common/interface/component.cmake
new file mode 100644
index 0000000..d567602
--- /dev/null
+++ b/components/rpc/common/interface/component.cmake
@@ -0,0 +1,18 @@
+#-------------------------------------------------------------------------------
+# Copyright (c) 2020, Arm Limited and Contributors. All rights reserved.
+#
+# SPDX-License-Identifier: BSD-3-Clause
+#
+#-------------------------------------------------------------------------------
+if (NOT DEFINED TGT)
+	message(FATAL_ERROR "mandatory parameter TGT is not defined.")
+endif()
+
+set_property(TARGET ${TGT} PROPERTY RPC_CALLER_PUBLIC_HEADER_FILES
+	"${CMAKE_CURRENT_LIST_DIR}/rpc_caller.h"
+	"${CMAKE_CURRENT_LIST_DIR}/rpc_status.h"
+	)
+
+target_include_directories(${TGT} PUBLIC
+	"${CMAKE_CURRENT_LIST_DIR}"
+	)