diff --git a/drivers/soc/mediatek/Makefile b/drivers/soc/mediatek/Makefile
index b017330..b442be9 100644
--- a/drivers/soc/mediatek/Makefile
+++ b/drivers/soc/mediatek/Makefile
@@ -1,5 +1,5 @@
 # SPDX-License-Identifier: GPL-2.0-only
 obj-$(CONFIG_MTK_CMDQ) += mtk-cmdq-helper.o
-obj-$(CONFIG_MTK_INFRACFG) += mtk-infracfg.o
+obj-$(CONFIG_MTK_INFRACFG) += mtk-infracfg.o mtk-scpsys-ext.o
 obj-$(CONFIG_MTK_PMIC_WRAP) += mtk-pmic-wrap.o
 obj-$(CONFIG_MTK_SCPSYS) += mtk-scpsys.o
diff --git a/drivers/soc/mediatek/mtk-scpsys-ext.c b/drivers/soc/mediatek/mtk-scpsys-ext.c
new file mode 100644
index 0000000..df402ac
--- /dev/null
+++ b/drivers/soc/mediatek/mtk-scpsys-ext.c
@@ -0,0 +1,101 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2018 MediaTek Inc.
+ * Author: Owen Chen <Owen.Chen@mediatek.com>
+ */
+#include <linux/ktime.h>
+#include <linux/mfd/syscon.h>
+#include <linux/of_device.h>
+#include <linux/regmap.h>
+#include "scpsys-ext.h"
+
+#define MTK_POLL_DELAY_US   10
+#define MTK_POLL_TIMEOUT    USEC_PER_SEC
+
+static int set_bus_protection(struct regmap *map, u32 mask,
+		u32 reg_set, u32 reg_sta, u32 reg_en)
+{
+	u32 val;
+
+	if (reg_set)
+		regmap_write(map, reg_set, mask);
+	else
+		regmap_update_bits(map, reg_en, mask, mask);
+
+	return regmap_read_poll_timeout(map, reg_sta,
+			val, (val & mask) == mask,
+			MTK_POLL_DELAY_US, MTK_POLL_TIMEOUT);
+}
+
+static int clear_bus_protection(struct regmap *map, u32 mask,
+		u32 reg_clr, u32 reg_sta, u32 reg_en, bool ignore_ack)
+{
+	u32 val;
+
+	if (reg_clr)
+		regmap_write(map, reg_clr, mask);
+	else
+		regmap_update_bits(map, reg_en, mask, 0);
+
+	if (ignore_ack)
+		return 0;
+
+	return regmap_read_poll_timeout(map, reg_sta,
+			val, !(val & mask),
+			MTK_POLL_DELAY_US, MTK_POLL_TIMEOUT);
+}
+
+int mtk_scpsys_ext_set_bus_protection(const struct bus_prot *bp_table,
+	struct regmap *infracfg, struct regmap *smi_common)
+{
+	int i;
+
+	for (i = 0; i < MAX_STEPS; i++) {
+		struct regmap *map = NULL;
+		int ret;
+
+		if (bp_table[i].type == INVALID_TYPE)
+			break;
+		else if (bp_table[i].type == IFR_TYPE)
+			map = infracfg;
+		else if (bp_table[i].type == SMI_TYPE)
+			map = smi_common;
+
+		ret = set_bus_protection(map,
+				bp_table[i].mask, bp_table[i].set_ofs,
+				bp_table[i].sta_ofs, bp_table[i].en_ofs);
+
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+int mtk_scpsys_ext_clear_bus_protection(const struct bus_prot *bp_table,
+	struct regmap *infracfg, struct regmap *smi_common)
+{
+	int i;
+
+	for (i = MAX_STEPS - 1; i >= 0; i--) {
+		struct regmap *map = NULL;
+		int ret;
+
+		if (bp_table[i].type == INVALID_TYPE)
+			continue;
+		else if (bp_table[i].type == IFR_TYPE)
+			map = infracfg;
+		else if (bp_table[i].type == SMI_TYPE)
+			map = smi_common;
+
+		ret = clear_bus_protection(map,
+				bp_table[i].mask, bp_table[i].clr_ofs,
+				bp_table[i].sta_ofs, bp_table[i].en_ofs,
+				bp_table[i].ignore_clr_ack);
+
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
diff --git a/drivers/soc/mediatek/mtk-scpsys.c b/drivers/soc/mediatek/mtk-scpsys.c
index db35a28..763ca58 100644
--- a/drivers/soc/mediatek/mtk-scpsys.c
+++ b/drivers/soc/mediatek/mtk-scpsys.c
@@ -11,7 +11,7 @@
 #include <linux/platform_device.h>
 #include <linux/pm_domain.h>
 #include <linux/regulator/consumer.h>
-#include <linux/soc/mediatek/infracfg.h>
+#include "scpsys-ext.h"
 
 #include <dt-bindings/power/mt2701-power.h>
 #include <dt-bindings/power/mt2712-power.h>
@@ -87,9 +87,9 @@
  * @ctl_offs: The offset for main power control register.
  * @sram_pdn_bits: The mask for sram power control bits.
  * @sram_pdn_ack_bits: The mask for sram power control acked bits.
- * @bus_prot_mask: The mask for single step bus protection.
  * @basic_clk_name: The basic clocks required by this power domain.
  * @caps: The flag for active wake-up action.
+ * @bp_table: The mask table for multiple step bus protection.
  */
 struct scp_domain_data {
 	const char *name;
@@ -97,9 +97,9 @@ struct scp_domain_data {
 	int ctl_offs;
 	u32 sram_pdn_bits;
 	u32 sram_pdn_ack_bits;
-	u32 bus_prot_mask;
 	const char *basic_clk_name[MAX_CLKS];
 	u8 caps;
+	struct bus_prot bp_table[MAX_STEPS];
 };
 
 struct scp;
@@ -123,8 +123,8 @@ struct scp {
 	struct device *dev;
 	void __iomem *base;
 	struct regmap *infracfg;
+	struct regmap *smi_common;
 	struct scp_ctrl_reg ctrl_reg;
-	bool bus_prot_reg_update;
 };
 
 struct scp_subdomain {
@@ -138,7 +138,6 @@ struct scp_soc_data {
 	const struct scp_subdomain *subdomains;
 	int num_subdomains;
 	const struct scp_ctrl_reg regs;
-	bool bus_prot_reg_update;
 };
 
 static int scpsys_domain_is_on(struct scp_domain *scpd)
@@ -252,24 +251,16 @@ static int scpsys_bus_protect_enable(struct scp_domain *scpd)
 {
 	struct scp *scp = scpd->scp;
 
-	if (!scpd->data->bus_prot_mask)
-		return 0;
-
-	return mtk_infracfg_set_bus_protection(scp->infracfg,
-			scpd->data->bus_prot_mask,
-			scp->bus_prot_reg_update);
+	return mtk_scpsys_ext_set_bus_protection(scpd->data->bp_table,
+			scp->infracfg, scp->smi_common);
 }
 
 static int scpsys_bus_protect_disable(struct scp_domain *scpd)
 {
 	struct scp *scp = scpd->scp;
 
-	if (!scpd->data->bus_prot_mask)
-		return 0;
-
-	return mtk_infracfg_clear_bus_protection(scp->infracfg,
-			scpd->data->bus_prot_mask,
-			scp->bus_prot_reg_update);
+	return mtk_scpsys_ext_clear_bus_protection(scpd->data->bp_table,
+			scp->infracfg, scp->smi_common);
 }
 
 static int scpsys_power_on(struct generic_pm_domain *genpd)
@@ -404,8 +395,7 @@ static int init_basic_clks(struct platform_device *pdev, struct clk **clk,
 
 static struct scp *init_scp(struct platform_device *pdev,
 			const struct scp_domain_data *scp_domain_data, int num,
-			const struct scp_ctrl_reg *scp_ctrl_reg,
-			bool bus_prot_reg_update)
+			const struct scp_ctrl_reg *scp_ctrl_reg)
 {
 	struct genpd_onecell_data *pd_data;
 	struct resource *res;
@@ -419,8 +409,6 @@ static struct scp *init_scp(struct platform_device *pdev,
 	scp->ctrl_reg.pwr_sta_offs = scp_ctrl_reg->pwr_sta_offs;
 	scp->ctrl_reg.pwr_sta2nd_offs = scp_ctrl_reg->pwr_sta2nd_offs;
 
-	scp->bus_prot_reg_update = bus_prot_reg_update;
-
 	scp->dev = &pdev->dev;
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
@@ -448,6 +436,17 @@ static struct scp *init_scp(struct platform_device *pdev,
 		return ERR_CAST(scp->infracfg);
 	}
 
+	scp->smi_common = syscon_regmap_lookup_by_phandle(pdev->dev.of_node,
+			"smi_comm");
+
+	if (scp->smi_common == ERR_PTR(-ENODEV)) {
+		scp->smi_common = NULL;
+	} else if (IS_ERR(scp->smi_common)) {
+		dev_err(&pdev->dev, "Cannot find smi_common controller: %ld\n",
+				PTR_ERR(scp->smi_common));
+		return ERR_CAST(scp->smi_common);
+	}
+
 	for (i = 0; i < num; i++) {
 		struct scp_domain *scpd = &scp->domains[i];
 		const struct scp_domain_data *data = &scp_domain_data[i];
@@ -530,8 +529,11 @@ static void mtk_register_power_domains(struct platform_device *pdev,
 		.name = "conn",
 		.sta_mask = PWR_STATUS_CONN,
 		.ctl_offs = SPM_CONN_PWR_CON,
-		.bus_prot_mask = MT2701_TOP_AXI_PROT_EN_CONN_M |
-				 MT2701_TOP_AXI_PROT_EN_CONN_S,
+		.bp_table = {
+			BUS_PROT(IFR_TYPE, 0, 0, 0x220, 0x228,
+				MT2701_TOP_AXI_PROT_EN_CONN_M |
+				MT2701_TOP_AXI_PROT_EN_CONN_S),
+		},
 		.caps = MTK_SCPD_ACTIVE_WAKEUP,
 	},
 	[MT2701_POWER_DOMAIN_DISP] = {
@@ -540,7 +542,10 @@ static void mtk_register_power_domains(struct platform_device *pdev,
 		.ctl_offs = SPM_DIS_PWR_CON,
 		.sram_pdn_bits = GENMASK(11, 8),
 		.basic_clk_name = {"mm"},
-		.bus_prot_mask = MT2701_TOP_AXI_PROT_EN_MM_M0,
+		.bp_table = {
+			BUS_PROT(IFR_TYPE, 0, 0, 0x220, 0x228,
+				MT2701_TOP_AXI_PROT_EN_MM_M0),
+		},
 		.caps = MTK_SCPD_ACTIVE_WAKEUP,
 	},
 	[MT2701_POWER_DOMAIN_MFG] = {
@@ -675,7 +680,10 @@ static void mtk_register_power_domains(struct platform_device *pdev,
 		.sram_pdn_bits = GENMASK(8, 8),
 		.sram_pdn_ack_bits = GENMASK(16, 16),
 		.basic_clk_name = {"mfg"},
-		.bus_prot_mask = BIT(14) | BIT(21) | BIT(23),
+		.bp_table = {
+			BUS_PROT(IFR_TYPE, 0x260, 0x264, 0x220, 0x228,
+				BIT(14) | BIT(21) | BIT(23)),
+		},
 		.caps = MTK_SCPD_ACTIVE_WAKEUP,
 	},
 	[MT2712_POWER_DOMAIN_MFG_SC1] = {
@@ -747,7 +755,10 @@ static void mtk_register_power_domains(struct platform_device *pdev,
 		.sram_pdn_bits = GENMASK(8, 8),
 		.sram_pdn_ack_bits = GENMASK(12, 12),
 		.basic_clk_name = {"mm"},
-		.bus_prot_mask = (BIT(1) | BIT(2)),
+		.bp_table = {
+			BUS_PROT(IFR_TYPE, 0, 0, 0x220, 0x228,
+				BIT(1) | BIT(2)),
+		},
 	},
 	[MT6797_POWER_DOMAIN_AUDIO] = {
 		.name = "audio",
@@ -794,7 +805,10 @@ static void mtk_register_power_domains(struct platform_device *pdev,
 		.ctl_offs = SPM_ETHSYS_PWR_CON,
 		.sram_pdn_bits = GENMASK(11, 8),
 		.sram_pdn_ack_bits = GENMASK(15, 12),
-		.bus_prot_mask = MT7622_TOP_AXI_PROT_EN_ETHSYS,
+		.bp_table = {
+			BUS_PROT(IFR_TYPE, 0, 0, 0x220, 0x228,
+				MT7622_TOP_AXI_PROT_EN_ETHSYS),
+		},
 		.caps = MTK_SCPD_ACTIVE_WAKEUP,
 	},
 	[MT7622_POWER_DOMAIN_HIF0] = {
@@ -804,7 +818,10 @@ static void mtk_register_power_domains(struct platform_device *pdev,
 		.sram_pdn_bits = GENMASK(11, 8),
 		.sram_pdn_ack_bits = GENMASK(15, 12),
 		.basic_clk_name = {"hif_sel"},
-		.bus_prot_mask = MT7622_TOP_AXI_PROT_EN_HIF0,
+		.bp_table = {
+			BUS_PROT(IFR_TYPE, 0, 0, 0x220, 0x228,
+				MT7622_TOP_AXI_PROT_EN_HIF0),
+		},
 		.caps = MTK_SCPD_ACTIVE_WAKEUP,
 	},
 	[MT7622_POWER_DOMAIN_HIF1] = {
@@ -814,7 +831,10 @@ static void mtk_register_power_domains(struct platform_device *pdev,
 		.sram_pdn_bits = GENMASK(11, 8),
 		.sram_pdn_ack_bits = GENMASK(15, 12),
 		.basic_clk_name = {"hif_sel"},
-		.bus_prot_mask = MT7622_TOP_AXI_PROT_EN_HIF1,
+		.bp_table = {
+			BUS_PROT(IFR_TYPE, 0, 0, 0x220, 0x228,
+				MT7622_TOP_AXI_PROT_EN_HIF1),
+		},
 		.caps = MTK_SCPD_ACTIVE_WAKEUP,
 	},
 	[MT7622_POWER_DOMAIN_WB] = {
@@ -823,7 +843,10 @@ static void mtk_register_power_domains(struct platform_device *pdev,
 		.ctl_offs = SPM_WB_PWR_CON,
 		.sram_pdn_bits = 0,
 		.sram_pdn_ack_bits = 0,
-		.bus_prot_mask = MT7622_TOP_AXI_PROT_EN_WB,
+		.bp_table = {
+			BUS_PROT(IFR_TYPE, 0, 0, 0x220, 0x228,
+				MT7622_TOP_AXI_PROT_EN_WB),
+		},
 		.caps = MTK_SCPD_ACTIVE_WAKEUP | MTK_SCPD_FWAIT_SRAM,
 	},
 };
@@ -837,8 +860,11 @@ static void mtk_register_power_domains(struct platform_device *pdev,
 		.name = "conn",
 		.sta_mask = PWR_STATUS_CONN,
 		.ctl_offs = SPM_CONN_PWR_CON,
-		.bus_prot_mask = MT2701_TOP_AXI_PROT_EN_CONN_M |
-				 MT2701_TOP_AXI_PROT_EN_CONN_S,
+		.bp_table = {
+			BUS_PROT(IFR_TYPE, 0, 0, 0x220, 0x228,
+				MT2701_TOP_AXI_PROT_EN_CONN_M |
+				MT2701_TOP_AXI_PROT_EN_CONN_S),
+		},
 		.caps = MTK_SCPD_ACTIVE_WAKEUP,
 	},
 	[MT7623A_POWER_DOMAIN_ETH] = {
@@ -903,8 +929,11 @@ static void mtk_register_power_domains(struct platform_device *pdev,
 		.sram_pdn_bits = GENMASK(11, 8),
 		.sram_pdn_ack_bits = GENMASK(12, 12),
 		.basic_clk_name = {"mm"},
-		.bus_prot_mask = MT8173_TOP_AXI_PROT_EN_MM_M0 |
-			MT8173_TOP_AXI_PROT_EN_MM_M1,
+		.bp_table = {
+			BUS_PROT(IFR_TYPE, 0, 0, 0x220, 0x228,
+				MT8173_TOP_AXI_PROT_EN_MM_M0 |
+				MT8173_TOP_AXI_PROT_EN_MM_M1),
+		},
 	},
 	[MT8173_POWER_DOMAIN_VENC_LT] = {
 		.name = "venc_lt",
@@ -950,10 +979,13 @@ static void mtk_register_power_domains(struct platform_device *pdev,
 		.ctl_offs = SPM_MFG_PWR_CON,
 		.sram_pdn_bits = GENMASK(13, 8),
 		.sram_pdn_ack_bits = GENMASK(21, 16),
-		.bus_prot_mask = MT8173_TOP_AXI_PROT_EN_MFG_S |
-			MT8173_TOP_AXI_PROT_EN_MFG_M0 |
-			MT8173_TOP_AXI_PROT_EN_MFG_M1 |
-			MT8173_TOP_AXI_PROT_EN_MFG_SNOOP_OUT,
+		.bp_table = {
+			BUS_PROT(IFR_TYPE, 0, 0, 0x220, 0x228,
+				MT8173_TOP_AXI_PROT_EN_MFG_S |
+				MT8173_TOP_AXI_PROT_EN_MFG_M0 |
+				MT8173_TOP_AXI_PROT_EN_MFG_M1 |
+				MT8173_TOP_AXI_PROT_EN_MFG_SNOOP_OUT),
+		},
 	},
 };
 
@@ -969,7 +1001,6 @@ static void mtk_register_power_domains(struct platform_device *pdev,
 		.pwr_sta_offs = SPM_PWR_STATUS,
 		.pwr_sta2nd_offs = SPM_PWR_STATUS_2ND
 	},
-	.bus_prot_reg_update = true,
 };
 
 static const struct scp_soc_data mt2712_data = {
@@ -981,7 +1012,6 @@ static void mtk_register_power_domains(struct platform_device *pdev,
 		.pwr_sta_offs = SPM_PWR_STATUS,
 		.pwr_sta2nd_offs = SPM_PWR_STATUS_2ND
 	},
-	.bus_prot_reg_update = false,
 };
 
 static const struct scp_soc_data mt6797_data = {
@@ -993,7 +1023,6 @@ static void mtk_register_power_domains(struct platform_device *pdev,
 		.pwr_sta_offs = SPM_PWR_STATUS_MT6797,
 		.pwr_sta2nd_offs = SPM_PWR_STATUS_2ND_MT6797
 	},
-	.bus_prot_reg_update = true,
 };
 
 static const struct scp_soc_data mt7622_data = {
@@ -1003,7 +1032,6 @@ static void mtk_register_power_domains(struct platform_device *pdev,
 		.pwr_sta_offs = SPM_PWR_STATUS,
 		.pwr_sta2nd_offs = SPM_PWR_STATUS_2ND
 	},
-	.bus_prot_reg_update = true,
 };
 
 static const struct scp_soc_data mt7623a_data = {
@@ -1013,7 +1041,6 @@ static void mtk_register_power_domains(struct platform_device *pdev,
 		.pwr_sta_offs = SPM_PWR_STATUS,
 		.pwr_sta2nd_offs = SPM_PWR_STATUS_2ND
 	},
-	.bus_prot_reg_update = true,
 };
 
 static const struct scp_soc_data mt8173_data = {
@@ -1025,7 +1052,6 @@ static void mtk_register_power_domains(struct platform_device *pdev,
 		.pwr_sta_offs = SPM_PWR_STATUS,
 		.pwr_sta2nd_offs = SPM_PWR_STATUS_2ND
 	},
-	.bus_prot_reg_update = true,
 };
 
 /*
@@ -1066,8 +1092,7 @@ static int scpsys_probe(struct platform_device *pdev)
 
 	soc = of_device_get_match_data(&pdev->dev);
 
-	scp = init_scp(pdev, soc->domains, soc->num_domains, &soc->regs,
-			soc->bus_prot_reg_update);
+	scp = init_scp(pdev, soc->domains, soc->num_domains, &soc->regs);
 	if (IS_ERR(scp))
 		return PTR_ERR(scp);
 
diff --git a/drivers/soc/mediatek/scpsys-ext.h b/drivers/soc/mediatek/scpsys-ext.h
new file mode 100644
index 0000000..458b2c5
--- /dev/null
+++ b/drivers/soc/mediatek/scpsys-ext.h
@@ -0,0 +1,67 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __SOC_MEDIATEK_SCPSYS_EXT_H
+#define __SOC_MEDIATEK_SCPSYS_EXT_H
+
+#define MAX_STEPS	4
+
+#define _BUS_PROT(_type, _set_ofs, _clr_ofs,			\
+		_en_ofs, _sta_ofs, _mask, _ignore_clr_ack) {	\
+		.type = _type,					\
+		.set_ofs = _set_ofs,				\
+		.clr_ofs = _clr_ofs,				\
+		.en_ofs = _en_ofs,				\
+		.sta_ofs = _sta_ofs,				\
+		.mask = _mask,					\
+		.ignore_clr_ack = _ignore_clr_ack,		\
+	}
+
+#define BUS_PROT(_type, _set_ofs, _clr_ofs,		\
+		_en_ofs, _sta_ofs, _mask)		\
+		_BUS_PROT(_type, _set_ofs, _clr_ofs,	\
+		_en_ofs, _sta_ofs, _mask, false)
+
+#define BUS_PROT_IGN(_type, _set_ofs, _clr_ofs,	\
+		_en_ofs, _sta_ofs, _mask)		\
+		_BUS_PROT(_type, _set_ofs, _clr_ofs,	\
+		_en_ofs, _sta_ofs, _mask, true)
+
+#define MT2701_TOP_AXI_PROT_EN_MM_M0		BIT(1)
+#define MT2701_TOP_AXI_PROT_EN_CONN_M		BIT(2)
+#define MT2701_TOP_AXI_PROT_EN_CONN_S		BIT(8)
+
+#define MT7622_TOP_AXI_PROT_EN_ETHSYS		(BIT(3) | BIT(17))
+#define MT7622_TOP_AXI_PROT_EN_HIF0		(BIT(24) | BIT(25))
+#define MT7622_TOP_AXI_PROT_EN_HIF1		(BIT(26) | BIT(27) | \
+						 BIT(28))
+#define MT7622_TOP_AXI_PROT_EN_WB		(BIT(2) | BIT(6) | \
+						 BIT(7) | BIT(8))
+
+#define MT8173_TOP_AXI_PROT_EN_MM_M0		BIT(1)
+#define MT8173_TOP_AXI_PROT_EN_MM_M1		BIT(2)
+#define MT8173_TOP_AXI_PROT_EN_MFG_S		BIT(14)
+#define MT8173_TOP_AXI_PROT_EN_MFG_M0		BIT(21)
+#define MT8173_TOP_AXI_PROT_EN_MFG_M1		BIT(22)
+#define MT8173_TOP_AXI_PROT_EN_MFG_SNOOP_OUT	BIT(23)
+
+enum regmap_type {
+	INVALID_TYPE = 0,
+	IFR_TYPE,
+	SMI_TYPE,
+};
+
+struct bus_prot {
+	enum regmap_type type;
+	u32 set_ofs;
+	u32 clr_ofs;
+	u32 en_ofs;
+	u32 sta_ofs;
+	u32 mask;
+	bool ignore_clr_ack;
+};
+
+int mtk_scpsys_ext_set_bus_protection(const struct bus_prot *bp_table,
+	struct regmap *infracfg, struct regmap *smi_common);
+int mtk_scpsys_ext_clear_bus_protection(const struct bus_prot *bp_table,
+	struct regmap *infracfg, struct regmap *smi_common);
+
+#endif /* __SOC_MEDIATEK_SCPSYS_EXT_H */
