diff --git a/include/drivers/arm/gic600ae_fmu.h b/include/drivers/arm/gic600ae_fmu.h
index 904a5f9..88b87b9 100644
--- a/include/drivers/arm/gic600ae_fmu.h
+++ b/include/drivers/arm/gic600ae_fmu.h
@@ -37,6 +37,7 @@
 /* SMEN constants */
 #define FMU_SMEN_BLK_SHIFT	U(8)
 #define FMU_SMEN_SMID_SHIFT	U(24)
+#define FMU_SMEN_EN_BIT		BIT(0)
 
 /* Error record IDs */
 #define FMU_BLK_GICD		U(0)