diff --git a/plat/mediatek/mt8188/include/platform_def.h b/plat/mediatek/mt8188/include/platform_def.h
index 7a30357..156a7e2 100644
--- a/plat/mediatek/mt8188/include/platform_def.h
+++ b/plat/mediatek/mt8188/include/platform_def.h
@@ -178,5 +178,6 @@
 #define PLAT_CPU_PM_B_BUCK_ISO_ID	(6)
 #define PLAT_CPU_PM_ILDO_ID		(6)
 #define CPU_IDLE_SRAM_BASE		(0x11B000)
+#define CPU_IDLE_SRAM_SIZE		(0x1000)
 
 #endif /* PLATFORM_DEF_H */