diff --git a/bl31/bl31.mk b/bl31/bl31.mk
index 3e665c5..ec70627 100644
--- a/bl31/bl31.mk
+++ b/bl31/bl31.mk
@@ -149,6 +149,7 @@
 
 ifeq (${DRTM_SUPPORT},1)
 BL31_SOURCES		+=	services/std_svc/drtm/drtm_main.c	\
+				services/std_svc/drtm/drtm_dma_prot.c	\
 				${MBEDTLS_SOURCES}
 endif