diff --git a/src/superio/nuvoton/Makefile.mk b/src/superio/nuvoton/Makefile.mk
index f56f5f4734..eab992a666 100644
--- a/src/superio/nuvoton/Makefile.mk
+++ b/src/superio/nuvoton/Makefile.mk
@@ -3,6 +3,8 @@
 ## include generic nuvoton pre-ram stage driver
 bootblock-$(CONFIG_SUPERIO_NUVOTON_COMMON_PRE_RAM) += common/early_serial.c
 romstage-$(CONFIG_SUPERIO_NUVOTON_COMMON_PRE_RAM) += common/early_serial.c
+## include generic nuvoton helper
+ramstage-$(CONFIG_SUPERIO_NUVOTON_COMMON_PRE_RAM) += common/common.c
 
 subdirs-$(CONFIG_SUPERIO_NUVOTON_WPCM450) += wpcm450
 subdirs-$(CONFIG_SUPERIO_NUVOTON_NCT5104D) += nct5104d
diff --git a/src/superio/nuvoton/common/Kconfig b/src/superio/nuvoton/common/Kconfig
index 2525c5d445..f3e8e4ae93 100644
--- a/src/superio/nuvoton/common/Kconfig
+++ b/src/superio/nuvoton/common/Kconfig
@@ -18,9 +18,8 @@ config HAVE_SHARED_PS2_PORT
 	help
 	  Select this option if your mainboard has a single PS/2 port for both keyboard and
 	  mouse, and where a Y-cable cannot allow both keyboard and mouse to work off the same
-	  port. This one port usually works for keyboards only. Add the nvram option
-	  "swap_keyboard_and_mouse" to cmos.layout to allow changing this port into a
-	  mouse port.
+	  port. This one port usually works for keyboards only. Add the nvram/CFR option
+	  "ps2_port_role" to allow changing this port into a mouse port.
 
 config SUPERIO_NUVOTON_PNP_BASE
 	hex
diff --git a/src/superio/nuvoton/common/common.c b/src/superio/nuvoton/common/common.c
new file mode 100644
index 0000000000..e2948cfb2d
--- /dev/null
+++ b/src/superio/nuvoton/common/common.c
@@ -0,0 +1,137 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+/*
+ * Configuration routines common to Nuvoton SIO chips,
+ * except nct5104d, nct6687d, npcd378, wpcm450.
+ */
+
+#include <console/console.h>
+#include <device/device.h>
+#include <device/pnp.h>
+#include <option.h>
+#include <pc80/keyboard.h>
+#include <superio/conf_mode.h>
+#include "nuvoton.h"
+
+#define MAINBOARD_POWER_OFF	0
+#define MAINBOARD_POWER_ON	1
+#define MAINBOARD_POWER_KEEP	2
+
+#define POWER_LOSS_CONTROL_SHIFT	5
+#define POWER_LOSS_CONTROL_MASK		(3 << POWER_LOSS_CONTROL_SHIFT)
+
+/* CR 0xe0 */
+#define KBD_WAKEUP_PSOUT	BIT(6)
+#define KBD_MS_SWAP		BIT(2)
+#define KBXKEY			BIT(0)
+/* CR 0xe4 */
+/* Power RAM in S3; for reference only; this needs to be enabled in bootblock */
+#define EN_3VSBSW		BIT(4)
+#define KBD_WAKEUP_ANYKEY	BIT(3)
+
+static void enable_ps2_mouse(struct device *dev, bool en)
+{
+	if (!CONFIG(HAVE_SHARED_PS2_PORT))
+		return;
+
+	pnp_enter_conf_mode(dev);
+	u8 bit = KBD_MS_SWAP;
+	/* pnp_set_logical_device() is not used because the bit is in another LD. */
+	pnp_write_config(dev, 0x7, NCT677X_ACPI);
+	pnp_unset_and_set_config(dev, 0xe0, bit, en ? bit : 0);
+	pnp_exit_conf_mode(dev);
+}
+
+void nuvoton_common_init(struct device *dev)
+{
+	u8 byte, role, mask;
+
+	if (!dev->enabled)
+		return;
+
+	switch (dev->path.pnp.device) {
+	case NCT677X_KBC:
+		/*
+		 * If mainboard has both PS/2 keyboard and mouse ports, bootblock code
+		 * should enable both and leave them enabled.
+		 */
+		role = PS2_PORT_ROLE_KEYBOARD;
+		if (CONFIG(HAVE_SHARED_PS2_PORT)) {
+			role = get_uint_option("ps2_port_role", PS2_PORT_ROLE_KEYBOARD);
+			if (role > PS2_PORT_ROLE_AUTO)
+				break; /* Invalid setting; abort */
+		}
+		if (role != PS2_PORT_ROLE_KEYBOARD) {
+			enable_ps2_mouse(dev, true);
+			if (role == PS2_PORT_ROLE_MOUSE)
+				break; /* Leave the port swapped; we're done */
+
+			/* This leaves PS2_PORT_ROLE_AUTO */
+			if (pc_keyboard_init(PROBE_AUX_DEVICE)) {
+				break; /* Mouse found; leave the port swapped */
+			} else {
+				printk(BIOS_INFO, "%s: Mouse not detected.\n", __func__);
+			}
+		}
+		/* Set port as keyboard, and initialize keyboard if enabled in Kconfig */
+		enable_ps2_mouse(dev, false);
+		pc_keyboard_init(NO_AUX_DEVICE);
+		break;
+	case NCT677X_ACPI:
+		pnp_enter_conf_mode(dev);
+		pnp_set_logical_device(dev);
+
+		/*
+		 * Keyboard wakeup: any key
+		 * NOTE: Bits related to keyboard wakeup are kept even in S5 (soft off),
+		 *       and will allow keyboard to wake system even from this state.
+		 *       Add SMM/ACPI code to turn it back off before entering S5.
+		 */
+		pnp_unset_and_set_config(dev, 0xe0, 0, KBD_WAKEUP_PSOUT | KBXKEY);
+
+		byte = KBD_WAKEUP_ANYKEY;
+		mask = 0;
+		/*
+		 * Set power state after power fail.
+		 *
+		 * Important: Make sure the definitions in mainboard/Kconfig around
+		 * MAINBOARD_POWER_FAILURE_STATE and your board's cmos.layout match.
+		 * And if MAINBOARD_POWER_FAILURE_STATE deviates from the chip's
+		 * expectation (ie. 0=off, 1=on, 2=keep), this code must be adapted.
+		 */
+		if (CONFIG(HAVE_POWER_STATE_AFTER_FAILURE)) {
+			unsigned int power_status = get_uint_option("power_on_after_fail",
+				CONFIG_MAINBOARD_POWER_FAILURE_STATE);
+
+			switch (power_status) {
+			case MAINBOARD_POWER_KEEP:
+				/*
+				 * KEEP power state is software emulated using USER and
+				 * a manually set power state.
+				 */
+				power_status = 3;
+				__fallthrough;
+			case MAINBOARD_POWER_OFF:
+			case MAINBOARD_POWER_ON:
+				byte |= (power_status << POWER_LOSS_CONTROL_SHIFT);
+				mask = POWER_LOSS_CONTROL_MASK;
+				break;
+			}
+			/* Log a "on" power state */
+			pnp_unset_and_set_config(dev, 0xe6, BIT(4), 0);
+		}
+
+		pnp_unset_and_set_config(dev, 0xe4, mask, byte);
+		pnp_exit_conf_mode(dev);
+		break;
+	}
+}
+
+struct device_operations nuvoton_common_ops = {
+	.read_resources   = noop_read_resources,
+	.set_resources    = pnp_set_resources,
+	.enable_resources = pnp_enable_resources,
+	.enable           = pnp_alt_enable,
+	.init             = nuvoton_common_init,
+	.ops_pnp_mode     = &pnp_conf_mode_8787_aa,
+};
diff --git a/src/superio/nuvoton/common/nuvoton.h b/src/superio/nuvoton/common/nuvoton.h
index 77eafeb240..1dd20923e0 100644
--- a/src/superio/nuvoton/common/nuvoton.h
+++ b/src/superio/nuvoton/common/nuvoton.h
@@ -4,6 +4,7 @@
 #define SUPERIO_NUVOTON_COMMON_H
 
 #ifndef __ACPI__
+#include <device/device.h>
 #include <device/pnp_type.h>
 #include <stdint.h>
 
@@ -31,11 +32,27 @@ static __always_inline void nuvoton_pnp_exit_conf_state(pnp_devfn_t dev)
 	outb(NUVOTON_EXIT_KEY, port);
 }
 
+void nuvoton_enable_serial(pnp_devfn_t dev, u16 iobase);
 #endif /* SIMPLE_DEVICE */
 
-void nuvoton_enable_serial(pnp_devfn_t dev, u16 iobase);
+#if ENV_RAMSTAGE
+extern struct device_operations nuvoton_common_ops;
+
+void nuvoton_common_init(struct device *dev);
 #endif
 
+#if ENV_SMM
+void nuvoton_smi_sleep(u8 slp_typ);
+#endif
+
+enum e_ps2role {
+	PS2_PORT_ROLE_KEYBOARD	= 0,
+	PS2_PORT_ROLE_MOUSE	= 1,
+	PS2_PORT_ROLE_AUTO	= 2
+};
+
+#endif /* __ACPI__ */
+
 /*
  * Logical Device Numbers (LDN) common to all Nuvoton SIOs.
  * Because they will be incorporated into ACPI device IDs,
diff --git a/src/superio/nuvoton/common/smm.c b/src/superio/nuvoton/common/smm.c
new file mode 100644
index 0000000000..9fdefc43b6
--- /dev/null
+++ b/src/superio/nuvoton/common/smm.c
@@ -0,0 +1,31 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+/*
+ * SMM routines common to Nuvoton NCTxxxx SIO chips,
+ * except 5104, 6687, npcd378, wpcm450.
+ */
+
+/* SMM code needs to be kept simple */
+#define __SIMPLE_DEVICE__
+
+#include <assert.h>
+#include <acpi/acpi.h>
+#include <arch/io.h>
+#include <device/pnp_ops.h>
+#include "nuvoton.h"
+
+#define ACPI_DEV   PNP_DEV(CONFIG_SUPERIO_NUVOTON_PNP_BASE, NCT677X_ACPI)
+
+void nuvoton_smi_sleep(u8 slp_typ)
+{
+	if (slp_typ != ACPI_S5)
+		return;
+
+	_Static_assert(CONFIG_SUPERIO_NUVOTON_PNP_BASE != 0,
+	       "Kconfig SUPERIO_NUVOTON_PNP_BASE must be set!");
+	nuvoton_pnp_enter_conf_state(ACPI_DEV);
+	pnp_set_logical_device(ACPI_DEV);
+	pnp_unset_and_set_config(ACPI_DEV, 0xe0, BIT(6), 0); /* KB wakeup off */
+	pnp_unset_and_set_config(ACPI_DEV, 0xe6, 0, BIT(4)); /* Power off */
+	nuvoton_pnp_exit_conf_state(ACPI_DEV);
+}