diff --git a/plat/mediatek/include/mtk_sip_def.h b/plat/mediatek/include/mtk_sip_def.h
new file mode 100644
index 0000000..b591499
--- /dev/null
+++ b/plat/mediatek/include/mtk_sip_def.h
@@ -0,0 +1,20 @@
+/*
+ * Copyright (c) 2022, MediaTek Inc. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef MTK_SIP_DEF_H
+#define MTK_SIP_DEF_H
+
+/* Define SiP SMC ID here */
+#define MTK_SIP_SMC_FROM_NS_EL1_TABLE(_func) \
+	_func(MTK_SIP_KERNEL_TIME_SYNC, 0x202) \
+	_func(MTK_SIP_VCORE_CONTROL, 0x506) \
+	_func(MTK_SIP_APUSYS_CONTROL, 0x51E) \
+	_func(MTK_SIP_KERNEL_GIC_OP, 0x526)
+
+#define MTK_SIP_SMC_FROM_BL33_TABLE(_func) \
+	_func(MTK_SIP_KERNEL_BOOT, 0x115)
+
+#endif /* MTK_SIP_DEF_H */
diff --git a/plat/mediatek/include/mtk_sip_svc.h b/plat/mediatek/include/mtk_sip_svc.h
new file mode 100644
index 0000000..ce51048
--- /dev/null
+++ b/plat/mediatek/include/mtk_sip_svc.h
@@ -0,0 +1,106 @@
+/*
+ * Copyright (c) 2022, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef MTK_SIP_SVC_H
+#define MTK_SIP_SVC_H
+
+#include <stdint.h>
+#include <lib/smccc.h>
+#include <mtk_sip_def.h>
+
+/* SMC function IDs for SiP Service queries */
+#define SIP_SVC_CALL_COUNT		U(0x8200ff00)
+#define SIP_SVC_UID			U(0x8200ff01)
+/* 0x8200ff02 is reserved */
+#define SIP_SVC_VERSION			U(0x8200ff03)
+
+/* MediaTek SiP Service Calls version numbers */
+#define MTK_SIP_SVC_VERSION_MAJOR	U(0x0)
+#define MTK_SIP_SVC_VERSION_MINOR	U(0x1)
+
+/* Number of MediaTek SiP Calls implemented */
+#define MTK_COMMON_SIP_NUM_CALLS	U(4)
+
+/* MediaTek SiP Service Calls function IDs */
+#define MTK_SIP_SET_AUTHORIZED_SECURE_REG	U(0x82000001)
+
+#define SMC_ID_EXPAND_AS_ENUM(_smc_id, _smc_num) \
+	_smc_id##_AARCH32 = ((SMC_TYPE_FAST << FUNCID_TYPE_SHIFT) | \
+		 ((0) << FUNCID_CC_SHIFT) | \
+		 (OEN_SIP_START << FUNCID_OEN_SHIFT) | \
+		 ((_smc_num) << FUNCID_NUM_SHIFT)), \
+	_smc_id##_AARCH64 = ((SMC_TYPE_FAST << FUNCID_TYPE_SHIFT) | \
+		 ((1) << FUNCID_CC_SHIFT) | \
+		 (OEN_SIP_START << FUNCID_OEN_SHIFT) | \
+		 ((_smc_num) << FUNCID_NUM_SHIFT)),
+
+#define SMC_ID_EXPAND_AS_EXTERN_SMC_INDEX(_smc_id, _smc_num) \
+	extern short _smc_id##_descriptor_index;
+
+/* Bind SMC handler with SMC ID */
+#define DECLARE_SMC_HANDLER(_smc_id, _smc_handler) \
+	const struct smc_descriptor _smc_id##_descriptor \
+		__used \
+		__aligned(sizeof(void *)) \
+		__section(".mtk_smc_descriptor_pool") = { \
+			.smc_handler = _smc_handler, \
+			.smc_name = #_smc_id, \
+			.smc_id_aarch32 = _smc_id##_AARCH32, \
+			.smc_id_aarch64 = _smc_id##_AARCH64, \
+			.smc_descriptor_index = &_smc_id##_descriptor_index \
+		}
+
+MTK_SIP_SMC_FROM_BL33_TABLE(SMC_ID_EXPAND_AS_EXTERN_SMC_INDEX);
+MTK_SIP_SMC_FROM_NS_EL1_TABLE(SMC_ID_EXPAND_AS_EXTERN_SMC_INDEX);
+
+/* Expand SiP SMC ID table as enum */
+enum {
+	MTK_SIP_SMC_FROM_BL33_TABLE(SMC_ID_EXPAND_AS_ENUM)
+	MTK_SIP_SMC_FROM_NS_EL1_TABLE(SMC_ID_EXPAND_AS_ENUM)
+	MTK_SIP_SMC_MAX_NUMBER
+};
+
+/* MediaTek SiP Calls error code */
+enum {
+	MTK_SIP_E_SUCCESS = 0,
+	MTK_SIP_E_INVALID_PARAM = -1,
+	MTK_SIP_E_NOT_SUPPORTED = -2,
+	MTK_SIP_E_INVALID_RANGE = -3,
+	MTK_SIP_E_PERMISSION_DENY = -4,
+	MTK_SIP_E_LOCK_FAIL = -5,
+};
+
+struct smccc_res {
+	uint64_t a1;
+	uint64_t a2;
+	uint64_t a3;
+};
+
+typedef uintptr_t (*smc_handler_t)(u_register_t,
+				   u_register_t,
+				   u_register_t,
+				   u_register_t,
+				   void *,
+				   struct smccc_res *);
+
+struct smc_descriptor {
+	smc_handler_t smc_handler;
+	const uint32_t smc_id_aarch32;
+	const uint32_t smc_id_aarch64;
+	const char *smc_name;
+	short *const smc_descriptor_index;
+};
+
+/*
+ * This function should be implemented in MediaTek SOC directory. It fullfills
+ * MTK_SIP_SET_AUTHORIZED_SECURE_REG SiP call by checking the sreg with the
+ * predefined secure register list, if a match was found, set val to sreg.
+ *
+ * Return MTK_SIP_E_SUCCESS on success, and MTK_SIP_E_INVALID_PARAM on failure.
+ */
+uint64_t mt_sip_set_authorized_sreg(uint32_t sreg, uint32_t val);
+
+#endif /* MTK_SIP_SVC_H */