diff --git a/include/drivers/st/scmi.h b/include/drivers/st/scmi.h
new file mode 100644
index 0000000..ac5dc38
--- /dev/null
+++ b/include/drivers/st/scmi.h
@@ -0,0 +1,29 @@
+/* SPDX-License-Identifier: BSD-3-Clause */
+/*
+ * Copyright (c) 2015-2019, Arm Limited and Contributors. All rights reserved.
+ */
+#ifndef SCMI_MSG_SCMI_H
+#define SCMI_MSG_SCMI_H
+
+#define SCMI_PROTOCOL_ID_BASE			0x10U
+#define SCMI_PROTOCOL_ID_POWER_DOMAIN		0x11U
+#define SCMI_PROTOCOL_ID_SYS_POWER		0x12U
+#define SCMI_PROTOCOL_ID_PERF			0x13U
+#define SCMI_PROTOCOL_ID_CLOCK			0x14U
+#define SCMI_PROTOCOL_ID_SENSOR			0x15U
+#define SCMI_PROTOCOL_ID_RESET_DOMAIN		0x16U
+
+/* SCMI error codes reported to agent through server-to-agent messages */
+#define SCMI_SUCCESS			0
+#define SCMI_NOT_SUPPORTED		(-1)
+#define SCMI_INVALID_PARAMETERS		(-2)
+#define SCMI_DENIED			(-3)
+#define SCMI_NOT_FOUND			(-4)
+#define SCMI_OUT_OF_RANGE		(-5)
+#define SCMI_BUSY			(-6)
+#define SCMI_COMMS_ERROR		(-7)
+#define SCMI_GENERIC_ERROR		(-8)
+#define SCMI_HARDWARE_ERROR		(-9)
+#define SCMI_PROTOCOL_ERROR		(-10)
+
+#endif /* SCMI_MSG_SCMI_H */