diff --git a/plat/arm/board/a5ds/include/platform_def.h b/plat/arm/board/a5ds/include/platform_def.h
index db65c37..13c1934 100644
--- a/plat/arm/board/a5ds/include/platform_def.h
+++ b/plat/arm/board/a5ds/include/platform_def.h
@@ -325,6 +325,14 @@
 
 /* Mailbox base address */
 #define A5DS_TRUSTED_MAILBOX_BASE	A5DS_SHARED_RAM_BASE
+#define A5DS_TRUSTED_MAILBOX_SIZE	(8 + A5DS_HOLD_SIZE)
+#define A5DS_HOLD_BASE		(A5DS_TRUSTED_MAILBOX_BASE + 8)
+#define A5DS_HOLD_SIZE		(PLATFORM_CORE_COUNT * \
+					 A5DS_HOLD_ENTRY_SIZE)
+#define A5DS_HOLD_ENTRY_SHIFT	3
+#define A5DS_HOLD_ENTRY_SIZE	(1 << A5DS_HOLD_ENTRY_SHIFT)
+#define A5DS_HOLD_STATE_WAIT	0
+#define A5DS_HOLD_STATE_GO	1
 
 /*
  * GIC related constants to cater for GICv2