diff --git a/drivers/thunderbolt/Makefile b/drivers/thunderbolt/Makefile
index c0b2fd73dfbd..2014bc840b06 100644
--- a/drivers/thunderbolt/Makefile
+++ b/drivers/thunderbolt/Makefile
@@ -1,4 +1,4 @@
 # SPDX-License-Identifier: GPL-2.0-only
 obj-${CONFIG_THUNDERBOLT} := thunderbolt.o
 thunderbolt-objs := nhi.o nhi_ops.o ctl.o tb.o switch.o cap.o path.o tunnel.o eeprom.o
-thunderbolt-objs += domain.o dma_port.o icm.o property.o xdomain.o lc.o usb4.o
+thunderbolt-objs += domain.o dma_port.o icm.o property.o xdomain.o lc.o tmu.o usb4.o
diff --git a/drivers/thunderbolt/switch.c b/drivers/thunderbolt/switch.c
index 2ccd1004920e..58e3f54ddbb9 100644
--- a/drivers/thunderbolt/switch.c
+++ b/drivers/thunderbolt/switch.c
@@ -2278,6 +2278,10 @@ int tb_switch_add(struct tb_switch *sw)
 		ret = tb_switch_update_link_attributes(sw);
 		if (ret)
 			return ret;
+
+		ret = tb_switch_tmu_init(sw);
+		if (ret)
+			return ret;
 	}
 
 	ret = device_add(&sw->dev);
diff --git a/drivers/thunderbolt/tb.c b/drivers/thunderbolt/tb.c
index 24e37e47dc48..f2868c125637 100644
--- a/drivers/thunderbolt/tb.c
+++ b/drivers/thunderbolt/tb.c
@@ -161,6 +161,25 @@ static void tb_scan_xdomain(struct tb_port *port)
 	}
 }
 
+static int tb_enable_tmu(struct tb_switch *sw)
+{
+	int ret;
+
+	/* If it is already enabled in correct mode, don't touch it */
+	if (tb_switch_tmu_is_enabled(sw))
+		return 0;
+
+	ret = tb_switch_tmu_disable(sw);
+	if (ret)
+		return ret;
+
+	ret = tb_switch_tmu_post_time(sw);
+	if (ret)
+		return ret;
+
+	return tb_switch_tmu_enable(sw);
+}
+
 static void tb_scan_port(struct tb_port *port);
 
 /**
@@ -263,6 +282,9 @@ static void tb_scan_port(struct tb_port *port)
 	if (tb_switch_lane_bonding_enable(sw))
 		tb_sw_warn(sw, "failed to enable lane bonding\n");
 
+	if (tb_enable_tmu(sw))
+		tb_sw_warn(sw, "failed to enable TMU\n");
+
 	tb_scan_switch(sw);
 }
 
@@ -713,6 +735,7 @@ static void tb_handle_hotplug(struct work_struct *work)
 			tb_sw_set_unplugged(port->remote->sw);
 			tb_free_invalid_tunnels(tb);
 			tb_remove_dp_resources(port->remote->sw);
+			tb_switch_tmu_disable(port->remote->sw);
 			tb_switch_lane_bonding_disable(port->remote->sw);
 			tb_switch_remove(port->remote->sw);
 			port->remote = NULL;
@@ -860,6 +883,9 @@ static int tb_start(struct tb *tb)
 		return ret;
 	}
 
+	/* Enable TMU if it is off */
+	if (!tb_switch_tmu_is_enabled(tb->root_switch))
+		tb_switch_tmu_enable(tb->root_switch);
 	/* Full scan to discover devices added before the driver was loaded. */
 	tb_scan_switch(tb->root_switch);
 	/* Find out tunnels created by the boot firmware */
@@ -891,6 +917,9 @@ static void tb_restore_children(struct tb_switch *sw)
 {
 	int i;
 
+	if (tb_enable_tmu(sw))
+		tb_sw_warn(sw, "failed to restore TMU configuration\n");
+
 	tb_switch_for_each_remote_port(sw, i) {
 		struct tb_port *port = &sw->ports[i];
 
diff --git a/drivers/thunderbolt/tb.h b/drivers/thunderbolt/tb.h
index 1488382066fd..087fd6d6ef9a 100644
--- a/drivers/thunderbolt/tb.h
+++ b/drivers/thunderbolt/tb.h
@@ -46,6 +46,38 @@ struct tb_switch_nvm {
 #define TB_SWITCH_MAX_DEPTH		6
 #define USB4_SWITCH_MAX_DEPTH		5
 
+/**
+ * enum tb_switch_tmu_rate - TMU refresh rate
+ * @TB_SWITCH_TMU_RATE_OFF: %0 (Disable Time Sync handshake)
+ * @TB_SWITCH_TMU_RATE_HIFI: %16 us time interval between successive
+ *			     transmission of the Delay Request TSNOS
+ *			     (Time Sync Notification Ordered Set) on a Link
+ * @TB_SWITCH_TMU_RATE_NORMAL: %1 ms time interval between successive
+ *			       transmission of the Delay Request TSNOS on
+ *			       a Link
+ */
+enum tb_switch_tmu_rate {
+	TB_SWITCH_TMU_RATE_OFF = 0,
+	TB_SWITCH_TMU_RATE_HIFI = 16,
+	TB_SWITCH_TMU_RATE_NORMAL = 1000,
+};
+
+/**
+ * struct tb_switch_tmu - Structure holding switch TMU configuration
+ * @cap: Offset to the TMU capability (%0 if not found)
+ * @has_ucap: Does the switch support uni-directional mode
+ * @rate: TMU refresh rate related to upstream switch. In case of root
+ *	  switch this holds the domain rate.
+ * @unidirectional: Is the TMU in uni-directional or bi-directional mode
+ *		    related to upstream switch. Don't case for root switch.
+ */
+struct tb_switch_tmu {
+	int cap;
+	bool has_ucap;
+	enum tb_switch_tmu_rate rate;
+	bool unidirectional;
+};
+
 /**
  * struct tb_switch - a thunderbolt switch
  * @dev: Device for the switch
@@ -55,6 +87,7 @@ struct tb_switch_nvm {
  *	      mailbox this will hold the pointer to that (%NULL
  *	      otherwise). If set it also means the switch has
  *	      upgradeable NVM.
+ * @tmu: The switch TMU configuration
  * @tb: Pointer to the domain the switch belongs to
  * @uid: Unique ID of the switch
  * @uuid: UUID of the switch (or %NULL if not supported)
@@ -93,6 +126,7 @@ struct tb_switch {
 	struct tb_regs_switch_header config;
 	struct tb_port *ports;
 	struct tb_dma_port *dma_port;
+	struct tb_switch_tmu tmu;
 	struct tb *tb;
 	u64 uid;
 	uuid_t *uuid;
@@ -129,6 +163,7 @@ struct tb_switch {
  * @remote: Remote port (%NULL if not connected)
  * @xdomain: Remote host (%NULL if not connected)
  * @cap_phy: Offset, zero if not found
+ * @cap_tmu: Offset of the adapter specific TMU capability (%0 if not present)
  * @cap_adap: Offset of the adapter specific capability (%0 if not present)
  * @cap_usb4: Offset to the USB4 port capability (%0 if not present)
  * @port: Port number on switch
@@ -147,6 +182,7 @@ struct tb_port {
 	struct tb_port *remote;
 	struct tb_xdomain *xdomain;
 	int cap_phy;
+	int cap_tmu;
 	int cap_adap;
 	int cap_usb4;
 	u8 port;
@@ -696,6 +732,17 @@ bool tb_switch_query_dp_resource(struct tb_switch *sw, struct tb_port *in);
 int tb_switch_alloc_dp_resource(struct tb_switch *sw, struct tb_port *in);
 void tb_switch_dealloc_dp_resource(struct tb_switch *sw, struct tb_port *in);
 
+int tb_switch_tmu_init(struct tb_switch *sw);
+int tb_switch_tmu_post_time(struct tb_switch *sw);
+int tb_switch_tmu_disable(struct tb_switch *sw);
+int tb_switch_tmu_enable(struct tb_switch *sw);
+
+static inline bool tb_switch_tmu_is_enabled(const struct tb_switch *sw)
+{
+	return sw->tmu.rate == TB_SWITCH_TMU_RATE_HIFI &&
+	       !sw->tmu.unidirectional;
+}
+
 int tb_wait_for_port(struct tb_port *port, bool wait_if_unplugged);
 int tb_port_add_nfc_credits(struct tb_port *port, int credits);
 int tb_port_set_initial_credits(struct tb_port *port, u32 credits);
diff --git a/drivers/thunderbolt/tb_regs.h b/drivers/thunderbolt/tb_regs.h
index 47f73f992412..ec1a5d1f7c94 100644
--- a/drivers/thunderbolt/tb_regs.h
+++ b/drivers/thunderbolt/tb_regs.h
@@ -26,6 +26,7 @@
 #define TB_MAX_CONFIG_RW_LENGTH 60
 
 enum tb_switch_cap {
+	TB_SWITCH_CAP_TMU		= 0x03,
 	TB_SWITCH_CAP_VSE		= 0x05,
 };
 
@@ -195,6 +196,21 @@ struct tb_regs_switch_header {
 #define ROUTER_CS_26_ONS			BIT(30)
 #define ROUTER_CS_26_OV				BIT(31)
 
+/* Router TMU configuration */
+#define TMU_RTR_CS_0				0x00
+#define TMU_RTR_CS_0_TD				BIT(27)
+#define TMU_RTR_CS_0_UCAP			BIT(30)
+#define TMU_RTR_CS_1				0x01
+#define TMU_RTR_CS_1_LOCAL_TIME_NS_MASK		GENMASK(31, 16)
+#define TMU_RTR_CS_1_LOCAL_TIME_NS_SHIFT	16
+#define TMU_RTR_CS_2				0x02
+#define TMU_RTR_CS_3				0x03
+#define TMU_RTR_CS_3_LOCAL_TIME_NS_MASK		GENMASK(15, 0)
+#define TMU_RTR_CS_3_TS_PACKET_INTERVAL_MASK	GENMASK(31, 16)
+#define TMU_RTR_CS_3_TS_PACKET_INTERVAL_SHIFT	16
+#define TMU_RTR_CS_22				0x16
+#define TMU_RTR_CS_24				0x18
+
 enum tb_port_type {
 	TB_TYPE_INACTIVE	= 0x000000,
 	TB_TYPE_PORT		= 0x000001,
@@ -248,6 +264,10 @@ struct tb_regs_port_header {
 #define ADP_CS_5_LCA_MASK			GENMASK(28, 22)
 #define ADP_CS_5_LCA_SHIFT			22
 
+/* TMU adapter registers */
+#define TMU_ADP_CS_3				0x03
+#define TMU_ADP_CS_3_UDM			BIT(29)
+
 /* Lane adapter registers */
 #define LANE_ADP_CS_0				0x00
 #define LANE_ADP_CS_0_SUPPORTED_WIDTH_MASK	GENMASK(25, 20)
diff --git a/drivers/thunderbolt/tmu.c b/drivers/thunderbolt/tmu.c
new file mode 100644
index 000000000000..d6314f6b20c7
--- /dev/null
+++ b/drivers/thunderbolt/tmu.c
@@ -0,0 +1,380 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Thunderbolt Time Management Unit (TMU) support
+ *
+ * Copyright (C) 2019, Intel Corporation
+ * Authors: Mika Westerberg <mika.westerberg@linux.intel.com>
+ *	    Rajmohan Mani <rajmohan.mani@intel.com>
+ */
+
+#include <linux/delay.h>
+
+#include "tb.h"
+
+static const char *tb_switch_tmu_mode_name(const struct tb_switch *sw)
+{
+	bool root_switch = !tb_route(sw);
+
+	switch (sw->tmu.rate) {
+	case TB_SWITCH_TMU_RATE_OFF:
+		return "off";
+
+	case TB_SWITCH_TMU_RATE_HIFI:
+		/* Root switch does not have upstream directionality */
+		if (root_switch)
+			return "HiFi";
+		if (sw->tmu.unidirectional)
+			return "uni-directional, HiFi";
+		return "bi-directional, HiFi";
+
+	case TB_SWITCH_TMU_RATE_NORMAL:
+		if (root_switch)
+			return "normal";
+		return "uni-directional, normal";
+
+	default:
+		return "unknown";
+	}
+}
+
+static bool tb_switch_tmu_ucap_supported(struct tb_switch *sw)
+{
+	int ret;
+	u32 val;
+
+	ret = tb_sw_read(sw, &val, TB_CFG_SWITCH,
+			 sw->tmu.cap + TMU_RTR_CS_0, 1);
+	if (ret)
+		return false;
+
+	return !!(val & TMU_RTR_CS_0_UCAP);
+}
+
+static int tb_switch_tmu_rate_read(struct tb_switch *sw)
+{
+	int ret;
+	u32 val;
+
+	ret = tb_sw_read(sw, &val, TB_CFG_SWITCH,
+			 sw->tmu.cap + TMU_RTR_CS_3, 1);
+	if (ret)
+		return ret;
+
+	val >>= TMU_RTR_CS_3_TS_PACKET_INTERVAL_SHIFT;
+	return val;
+}
+
+static int tb_switch_tmu_rate_write(struct tb_switch *sw, int rate)
+{
+	int ret;
+	u32 val;
+
+	ret = tb_sw_read(sw, &val, TB_CFG_SWITCH,
+			 sw->tmu.cap + TMU_RTR_CS_3, 1);
+	if (ret)
+		return ret;
+
+	val &= ~TMU_RTR_CS_3_TS_PACKET_INTERVAL_MASK;
+	val |= rate << TMU_RTR_CS_3_TS_PACKET_INTERVAL_SHIFT;
+
+	return tb_sw_write(sw, &val, TB_CFG_SWITCH,
+			   sw->tmu.cap + TMU_RTR_CS_3, 1);
+}
+
+static int tb_port_tmu_write(struct tb_port *port, u8 offset, u32 mask,
+			     u32 value)
+{
+	u32 data;
+	int ret;
+
+	ret = tb_port_read(port, &data, TB_CFG_PORT, port->cap_tmu + offset, 1);
+	if (ret)
+		return ret;
+
+	data &= ~mask;
+	data |= value;
+
+	return tb_port_write(port, &data, TB_CFG_PORT,
+			     port->cap_tmu + offset, 1);
+}
+
+static int tb_port_tmu_set_unidirectional(struct tb_port *port,
+					  bool unidirectional)
+{
+	u32 val;
+
+	if (!port->sw->tmu.has_ucap)
+		return 0;
+
+	val = unidirectional ? TMU_ADP_CS_3_UDM : 0;
+	return tb_port_tmu_write(port, TMU_ADP_CS_3, TMU_ADP_CS_3_UDM, val);
+}
+
+static inline int tb_port_tmu_unidirectional_disable(struct tb_port *port)
+{
+	return tb_port_tmu_set_unidirectional(port, false);
+}
+
+static bool tb_port_tmu_is_unidirectional(struct tb_port *port)
+{
+	int ret;
+	u32 val;
+
+	ret = tb_port_read(port, &val, TB_CFG_PORT,
+			   port->cap_tmu + TMU_ADP_CS_3, 1);
+	if (ret)
+		return false;
+
+	return val & TMU_ADP_CS_3_UDM;
+}
+
+static int tb_switch_tmu_set_time_disruption(struct tb_switch *sw, bool set)
+{
+	int ret;
+	u32 val;
+
+	ret = tb_sw_read(sw, &val, TB_CFG_SWITCH,
+			 sw->tmu.cap + TMU_RTR_CS_0, 1);
+	if (ret)
+		return ret;
+
+	if (set)
+		val |= TMU_RTR_CS_0_TD;
+	else
+		val &= ~TMU_RTR_CS_0_TD;
+
+	return tb_sw_write(sw, &val, TB_CFG_SWITCH,
+			   sw->tmu.cap + TMU_RTR_CS_0, 1);
+}
+
+/**
+ * tb_switch_tmu_init() - Initialize switch TMU structures
+ * @sw: Switch to initialized
+ *
+ * This function must be called before other TMU related functions to
+ * makes the internal structures are filled in correctly. Does not
+ * change any hardware configuration.
+ */
+int tb_switch_tmu_init(struct tb_switch *sw)
+{
+	int ret, i;
+
+	if (tb_switch_is_icm(sw))
+		return 0;
+
+	ret = tb_switch_find_cap(sw, TB_SWITCH_CAP_TMU);
+	if (ret > 0)
+		sw->tmu.cap = ret;
+
+	tb_switch_for_each_port(sw, i) {
+		struct tb_port *port = &sw->ports[i];
+		int cap;
+
+		cap = tb_port_find_cap(port, TB_PORT_CAP_TIME1);
+		if (cap > 0)
+			port->cap_tmu = cap;
+	}
+
+	ret = tb_switch_tmu_rate_read(sw);
+	if (ret < 0)
+		return ret;
+
+	sw->tmu.rate = ret;
+
+	sw->tmu.has_ucap = tb_switch_tmu_ucap_supported(sw);
+	if (sw->tmu.has_ucap) {
+		tb_sw_dbg(sw, "TMU: supports uni-directional mode\n");
+
+		if (tb_route(sw)) {
+			struct tb_port *up = tb_upstream_port(sw);
+
+			sw->tmu.unidirectional =
+				tb_port_tmu_is_unidirectional(up);
+		}
+	} else {
+		sw->tmu.unidirectional = false;
+	}
+
+	tb_sw_dbg(sw, "TMU: current mode: %s\n", tb_switch_tmu_mode_name(sw));
+	return 0;
+}
+
+/**
+ * tb_switch_tmu_post_time() - Update switch local time
+ * @sw: Switch whose time to update
+ *
+ * Updates switch local time using time posting procedure.
+ */
+int tb_switch_tmu_post_time(struct tb_switch *sw)
+{
+	unsigned int  post_local_time_offset, post_time_offset;
+	struct tb_switch *root_switch = sw->tb->root_switch;
+	u64 hi, mid, lo, local_time, post_time;
+	int i, ret, retries = 100;
+	u32 gm_local_time[3];
+
+	if (!tb_route(sw))
+		return 0;
+
+	if (!tb_switch_is_usb4(sw))
+		return 0;
+
+	/* Need to be able to read the grand master time */
+	if (!root_switch->tmu.cap)
+		return 0;
+
+	ret = tb_sw_read(root_switch, gm_local_time, TB_CFG_SWITCH,
+			 root_switch->tmu.cap + TMU_RTR_CS_1,
+			 ARRAY_SIZE(gm_local_time));
+	if (ret)
+		return ret;
+
+	for (i = 0; i < ARRAY_SIZE(gm_local_time); i++)
+		tb_sw_dbg(root_switch, "local_time[%d]=0x%08x\n", i,
+			  gm_local_time[i]);
+
+	/* Convert to nanoseconds (drop fractional part) */
+	hi = gm_local_time[2] & TMU_RTR_CS_3_LOCAL_TIME_NS_MASK;
+	mid = gm_local_time[1];
+	lo = (gm_local_time[0] & TMU_RTR_CS_1_LOCAL_TIME_NS_MASK) >>
+		TMU_RTR_CS_1_LOCAL_TIME_NS_SHIFT;
+	local_time = hi << 48 | mid << 16 | lo;
+
+	/* Tell the switch that time sync is disrupted for a while */
+	ret = tb_switch_tmu_set_time_disruption(sw, true);
+	if (ret)
+		return ret;
+
+	post_local_time_offset = sw->tmu.cap + TMU_RTR_CS_22;
+	post_time_offset = sw->tmu.cap + TMU_RTR_CS_24;
+
+	/*
+	 * Write the Grandmaster time to the Post Local Time registers
+	 * of the new switch.
+	 */
+	ret = tb_sw_write(sw, &local_time, TB_CFG_SWITCH,
+			  post_local_time_offset, 2);
+	if (ret)
+		goto out;
+
+	/*
+	 * Have the new switch update its local time (by writing 1 to
+	 * the post_time registers) and wait for the completion of the
+	 * same (post_time register becomes 0). This means the time has
+	 * been converged properly.
+	 */
+	post_time = 1;
+
+	ret = tb_sw_write(sw, &post_time, TB_CFG_SWITCH, post_time_offset, 2);
+	if (ret)
+		goto out;
+
+	do {
+		usleep_range(5, 10);
+		ret = tb_sw_read(sw, &post_time, TB_CFG_SWITCH,
+				 post_time_offset, 2);
+		if (ret)
+			goto out;
+	} while (--retries && post_time);
+
+	if (!retries) {
+		ret = -ETIMEDOUT;
+		goto out;
+	}
+
+	tb_sw_dbg(sw, "TMU: updated local time to %#llx\n", local_time);
+
+out:
+	tb_switch_tmu_set_time_disruption(sw, false);
+	return ret;
+}
+
+/**
+ * tb_switch_tmu_disable() - Disable TMU of a switch
+ * @sw: Switch whose TMU to disable
+ *
+ * Turns off TMU of @sw if it is enabled. If not enabled does nothing.
+ */
+int tb_switch_tmu_disable(struct tb_switch *sw)
+{
+	int ret;
+
+	if (!tb_switch_is_usb4(sw))
+		return 0;
+
+	/* Already disabled? */
+	if (sw->tmu.rate == TB_SWITCH_TMU_RATE_OFF)
+		return 0;
+
+	if (sw->tmu.unidirectional) {
+		struct tb_switch *parent = tb_switch_parent(sw);
+		struct tb_port *up, *down;
+
+		up = tb_upstream_port(sw);
+		down = tb_port_at(tb_route(sw), parent);
+
+		/* The switch may be unplugged so ignore any errors */
+		tb_port_tmu_unidirectional_disable(up);
+		ret = tb_port_tmu_unidirectional_disable(down);
+		if (ret)
+			return ret;
+	}
+
+	tb_switch_tmu_rate_write(sw, TB_SWITCH_TMU_RATE_OFF);
+
+	sw->tmu.unidirectional = false;
+	sw->tmu.rate = TB_SWITCH_TMU_RATE_OFF;
+
+	tb_sw_dbg(sw, "TMU: disabled\n");
+	return 0;
+}
+
+/**
+ * tb_switch_tmu_enable() - Enable TMU on a switch
+ * @sw: Switch whose TMU to enable
+ *
+ * Enables TMU of a switch to be in bi-directional, HiFi mode. In this mode
+ * all tunneling should work.
+ */
+int tb_switch_tmu_enable(struct tb_switch *sw)
+{
+	int ret;
+
+	if (!tb_switch_is_usb4(sw))
+		return 0;
+
+	ret = tb_switch_tmu_set_time_disruption(sw, true);
+	if (ret)
+		return ret;
+
+	/* Change mode to bi-directional */
+	if (tb_route(sw) && sw->tmu.unidirectional) {
+		struct tb_switch *parent = tb_switch_parent(sw);
+		struct tb_port *up, *down;
+
+		up = tb_upstream_port(sw);
+		down = tb_port_at(tb_route(sw), parent);
+
+		ret = tb_port_tmu_unidirectional_disable(down);
+		if (ret)
+			return ret;
+
+		ret = tb_switch_tmu_rate_write(sw, TB_SWITCH_TMU_RATE_HIFI);
+		if (ret)
+			return ret;
+
+		ret = tb_port_tmu_unidirectional_disable(up);
+		if (ret)
+			return ret;
+	} else {
+		ret = tb_switch_tmu_rate_write(sw, TB_SWITCH_TMU_RATE_HIFI);
+		if (ret)
+			return ret;
+	}
+
+	sw->tmu.unidirectional = false;
+	sw->tmu.rate = TB_SWITCH_TMU_RATE_HIFI;
+	tb_sw_dbg(sw, "TMU: mode set to: %s\n", tb_switch_tmu_mode_name(sw));
+
+	return tb_switch_tmu_set_time_disruption(sw, false);
+}
