diff --git a/include/arch/aarch64/arch.h b/include/arch/aarch64/arch.h
index 81e0f27..92e6737 100644
--- a/include/arch/aarch64/arch.h
+++ b/include/arch/aarch64/arch.h
@@ -226,6 +226,12 @@
 #define ID_AA64MMFR0_EL1_TGRAN16_SUPPORTED	ULL(0x1)
 #define ID_AA64MMFR0_EL1_TGRAN16_NOT_SUPPORTED	ULL(0x0)
 
+/* ID_AA64MMFR1_EL1 definitions */
+#define ID_AA64MMFR1_EL1_TWED_SHIFT		U(32)
+#define ID_AA64MMFR1_EL1_TWED_MASK		ULL(0xf)
+#define ID_AA64MMFR1_EL1_TWED_SUPPORTED		ULL(0x1)
+#define ID_AA64MMFR1_EL1_TWED_NOT_SUPPORTED	ULL(0x0)
+
 /* ID_AA64MMFR2_EL1 definitions */
 #define ID_AA64MMFR2_EL1		S3_0_C0_C7_2
 
@@ -312,6 +318,9 @@
 
 /* SCR definitions */
 #define SCR_RES1_BITS		((U(1) << 4) | (U(1) << 5))
+#define SCR_TWEDEL_SHIFT	U(30)
+#define SCR_TWEDEL_MASK		ULL(0xf)
+#define SCR_TWEDEn_BIT		(UL(1) << 29)
 #define SCR_ATA_BIT		(U(1) << 26)
 #define SCR_FIEN_BIT		(U(1) << 21)
 #define SCR_EEL2_BIT		(U(1) << 18)