diff --git a/plat/rockchip/px30/px30_def.h b/plat/rockchip/px30/px30_def.h
index 283b606..efe789e 100644
--- a/plat/rockchip/px30/px30_def.h
+++ b/plat/rockchip/px30/px30_def.h
@@ -11,6 +11,7 @@
 #define MINOR_VERSION		(0)
 
 #define SIZE_K(n)		((n) * 1024)
+#define SIZE_M(n)		((n) * 1024 * 1024)
 
 #define WITH_16BITS_WMSK(bits)	(0xffff0000 | (bits))