Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2863 insertions, 0 deletions

diff --git a/drivers/thunderbolt/usb4.c b/drivers/thunderbolt/usb4.c
new file mode 100644
index 0000000000..05ddb224c4
--- /dev/null
+++ b/drivers/thunderbolt/usb4.c
@@ -0,0 +1,2863 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * USB4 specific functionality
+ *
+ * Copyright (C) 2019, Intel Corporation
+ * Authors: Mika Westerberg <mika.westerberg@linux.intel.com>
+ *	    Rajmohan Mani <rajmohan.mani@intel.com>
+ */
+
+#include <linux/delay.h>
+#include <linux/ktime.h>
+#include <linux/units.h>
+
+#include "sb_regs.h"
+#include "tb.h"
+
+#define USB4_DATA_RETRIES		3
+#define USB4_DATA_DWORDS		16
+
+enum usb4_sb_target {
+	USB4_SB_TARGET_ROUTER,
+	USB4_SB_TARGET_PARTNER,
+	USB4_SB_TARGET_RETIMER,
+};
+
+#define USB4_NVM_READ_OFFSET_MASK	GENMASK(23, 2)
+#define USB4_NVM_READ_OFFSET_SHIFT	2
+#define USB4_NVM_READ_LENGTH_MASK	GENMASK(27, 24)
+#define USB4_NVM_READ_LENGTH_SHIFT	24
+
+#define USB4_NVM_SET_OFFSET_MASK	USB4_NVM_READ_OFFSET_MASK
+#define USB4_NVM_SET_OFFSET_SHIFT	USB4_NVM_READ_OFFSET_SHIFT
+
+#define USB4_DROM_ADDRESS_MASK		GENMASK(14, 2)
+#define USB4_DROM_ADDRESS_SHIFT		2
+#define USB4_DROM_SIZE_MASK		GENMASK(19, 15)
+#define USB4_DROM_SIZE_SHIFT		15
+
+#define USB4_NVM_SECTOR_SIZE_MASK	GENMASK(23, 0)
+
+#define USB4_BA_LENGTH_MASK		GENMASK(7, 0)
+#define USB4_BA_INDEX_MASK		GENMASK(15, 0)
+
+enum usb4_ba_index {
+	USB4_BA_MAX_USB3 = 0x1,
+	USB4_BA_MIN_DP_AUX = 0x2,
+	USB4_BA_MIN_DP_MAIN = 0x3,
+	USB4_BA_MAX_PCIE = 0x4,
+	USB4_BA_MAX_HI = 0x5,
+};
+
+#define USB4_BA_VALUE_MASK		GENMASK(31, 16)
+#define USB4_BA_VALUE_SHIFT		16
+
+static int usb4_native_switch_op(struct tb_switch *sw, u16 opcode,
+				 u32 *metadata, u8 *status,
+				 const void *tx_data, size_t tx_dwords,
+				 void *rx_data, size_t rx_dwords)
+{
+	u32 val;
+	int ret;
+
+	if (metadata) {
+		ret = tb_sw_write(sw, metadata, TB_CFG_SWITCH, ROUTER_CS_25, 1);
+		if (ret)
+			return ret;
+	}
+	if (tx_dwords) {
+		ret = tb_sw_write(sw, tx_data, TB_CFG_SWITCH, ROUTER_CS_9,
+				  tx_dwords);
+		if (ret)
+			return ret;
+	}
+
+	val = opcode | ROUTER_CS_26_OV;
+	ret = tb_sw_write(sw, &val, TB_CFG_SWITCH, ROUTER_CS_26, 1);
+	if (ret)
+		return ret;
+
+	ret = tb_switch_wait_for_bit(sw, ROUTER_CS_26, ROUTER_CS_26_OV, 0, 500);
+	if (ret)
+		return ret;
+
+	ret = tb_sw_read(sw, &val, TB_CFG_SWITCH, ROUTER_CS_26, 1);
+	if (ret)
+		return ret;
+
+	if (val & ROUTER_CS_26_ONS)
+		return -EOPNOTSUPP;
+
+	if (status)
+		*status = (val & ROUTER_CS_26_STATUS_MASK) >>
+			ROUTER_CS_26_STATUS_SHIFT;
+
+	if (metadata) {
+		ret = tb_sw_read(sw, metadata, TB_CFG_SWITCH, ROUTER_CS_25, 1);
+		if (ret)
+			return ret;
+	}
+	if (rx_dwords) {
+		ret = tb_sw_read(sw, rx_data, TB_CFG_SWITCH, ROUTER_CS_9,
+				 rx_dwords);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int __usb4_switch_op(struct tb_switch *sw, u16 opcode, u32 *metadata,
+			    u8 *status, const void *tx_data, size_t tx_dwords,
+			    void *rx_data, size_t rx_dwords)
+{
+	const struct tb_cm_ops *cm_ops = sw->tb->cm_ops;
+
+	if (tx_dwords > USB4_DATA_DWORDS || rx_dwords > USB4_DATA_DWORDS)
+		return -EINVAL;
+
+	/*
+	 * If the connection manager implementation provides USB4 router
+	 * operation proxy callback, call it here instead of running the
+	 * operation natively.
+	 */
+	if (cm_ops->usb4_switch_op) {
+		int ret;
+
+		ret = cm_ops->usb4_switch_op(sw, opcode, metadata, status,
+					     tx_data, tx_dwords, rx_data,
+					     rx_dwords);
+		if (ret != -EOPNOTSUPP)
+			return ret;
+
+		/*
+		 * If the proxy was not supported then run the native
+		 * router operation instead.
+		 */
+	}
+
+	return usb4_native_switch_op(sw, opcode, metadata, status, tx_data,
+				     tx_dwords, rx_data, rx_dwords);
+}
+
+static inline int usb4_switch_op(struct tb_switch *sw, u16 opcode,
+				 u32 *metadata, u8 *status)
+{
+	return __usb4_switch_op(sw, opcode, metadata, status, NULL, 0, NULL, 0);
+}
+
+static inline int usb4_switch_op_data(struct tb_switch *sw, u16 opcode,
+				      u32 *metadata, u8 *status,
+				      const void *tx_data, size_t tx_dwords,
+				      void *rx_data, size_t rx_dwords)
+{
+	return __usb4_switch_op(sw, opcode, metadata, status, tx_data,
+				tx_dwords, rx_data, rx_dwords);
+}
+
+static void usb4_switch_check_wakes(struct tb_switch *sw)
+{
+	bool wakeup_usb4 = false;
+	struct usb4_port *usb4;
+	struct tb_port *port;
+	bool wakeup = false;
+	u32 val;
+
+	if (!device_may_wakeup(&sw->dev))
+		return;
+
+	if (tb_route(sw)) {
+		if (tb_sw_read(sw, &val, TB_CFG_SWITCH, ROUTER_CS_6, 1))
+			return;
+
+		tb_sw_dbg(sw, "PCIe wake: %s, USB3 wake: %s\n",
+			  (val & ROUTER_CS_6_WOPS) ? "yes" : "no",
+			  (val & ROUTER_CS_6_WOUS) ? "yes" : "no");
+
+		wakeup = val & (ROUTER_CS_6_WOPS | ROUTER_CS_6_WOUS);
+	}
+
+	/*
+	 * Check for any downstream ports for USB4 wake,
+	 * connection wake and disconnection wake.
+	 */
+	tb_switch_for_each_port(sw, port) {
+		if (!port->cap_usb4)
+			continue;
+
+		if (tb_port_read(port, &val, TB_CFG_PORT,
+				 port->cap_usb4 + PORT_CS_18, 1))
+			break;
+
+		tb_port_dbg(port, "USB4 wake: %s, connection wake: %s, disconnection wake: %s\n",
+			    (val & PORT_CS_18_WOU4S) ? "yes" : "no",
+			    (val & PORT_CS_18_WOCS) ? "yes" : "no",
+			    (val & PORT_CS_18_WODS) ? "yes" : "no");
+
+		wakeup_usb4 = val & (PORT_CS_18_WOU4S | PORT_CS_18_WOCS |
+				     PORT_CS_18_WODS);
+
+		usb4 = port->usb4;
+		if (device_may_wakeup(&usb4->dev) && wakeup_usb4)
+			pm_wakeup_event(&usb4->dev, 0);
+
+		wakeup |= wakeup_usb4;
+	}
+
+	if (wakeup)
+		pm_wakeup_event(&sw->dev, 0);
+}
+
+static bool link_is_usb4(struct tb_port *port)
+{
+	u32 val;
+
+	if (!port->cap_usb4)
+		return false;
+
+	if (tb_port_read(port, &val, TB_CFG_PORT,
+			 port->cap_usb4 + PORT_CS_18, 1))
+		return false;
+
+	return !(val & PORT_CS_18_TCM);
+}
+
+/**
+ * usb4_switch_setup() - Additional setup for USB4 device
+ * @sw: USB4 router to setup
+ *
+ * USB4 routers need additional settings in order to enable all the
+ * tunneling. This function enables USB and PCIe tunneling if it can be
+ * enabled (e.g the parent switch also supports them). If USB tunneling
+ * is not available for some reason (like that there is Thunderbolt 3
+ * switch upstream) then the internal xHCI controller is enabled
+ * instead.
+ *
+ * This does not set the configuration valid bit of the router. To do
+ * that call usb4_switch_configuration_valid().
+ */
+int usb4_switch_setup(struct tb_switch *sw)
+{
+	struct tb_switch *parent = tb_switch_parent(sw);
+	struct tb_port *down;
+	bool tbt3, xhci;
+	u32 val = 0;
+	int ret;
+
+	usb4_switch_check_wakes(sw);
+
+	if (!tb_route(sw))
+		return 0;
+
+	ret = tb_sw_read(sw, &val, TB_CFG_SWITCH, ROUTER_CS_6, 1);
+	if (ret)
+		return ret;
+
+	down = tb_switch_downstream_port(sw);
+	sw->link_usb4 = link_is_usb4(down);
+	tb_sw_dbg(sw, "link: %s\n", sw->link_usb4 ? "USB4" : "TBT");
+
+	xhci = val & ROUTER_CS_6_HCI;
+	tbt3 = !(val & ROUTER_CS_6_TNS);
+
+	tb_sw_dbg(sw, "TBT3 support: %s, xHCI: %s\n",
+		  tbt3 ? "yes" : "no", xhci ? "yes" : "no");
+
+	ret = tb_sw_read(sw, &val, TB_CFG_SWITCH, ROUTER_CS_5, 1);
+	if (ret)
+		return ret;
+
+	if (tb_acpi_may_tunnel_usb3() && sw->link_usb4 &&
+	    tb_switch_find_port(parent, TB_TYPE_USB3_DOWN)) {
+		val |= ROUTER_CS_5_UTO;
+		xhci = false;
+	}
+
+	/*
+	 * Only enable PCIe tunneling if the parent router supports it
+	 * and it is not disabled.
+	 */
+	if (tb_acpi_may_tunnel_pcie() &&
+	    tb_switch_find_port(parent, TB_TYPE_PCIE_DOWN)) {
+		val |= ROUTER_CS_5_PTO;
+		/*
+		 * xHCI can be enabled if PCIe tunneling is supported
+		 * and the parent does not have any USB3 dowstream
+		 * adapters (so we cannot do USB 3.x tunneling).
+		 */
+		if (xhci)
+			val |= ROUTER_CS_5_HCO;
+	}
+
+	/* TBT3 supported by the CM */
+	val |= ROUTER_CS_5_C3S;
+
+	return tb_sw_write(sw, &val, TB_CFG_SWITCH, ROUTER_CS_5, 1);
+}
+
+/**
+ * usb4_switch_configuration_valid() - Set tunneling configuration to be valid
+ * @sw: USB4 router
+ *
+ * Sets configuration valid bit for the router. Must be called before
+ * any tunnels can be set through the router and after
+ * usb4_switch_setup() has been called. Can be called to host and device
+ * routers (does nothing for the latter).
+ *
+ * Returns %0 in success and negative errno otherwise.
+ */
+int usb4_switch_configuration_valid(struct tb_switch *sw)
+{
+	u32 val;
+	int ret;
+
+	if (!tb_route(sw))
+		return 0;
+
+	ret = tb_sw_read(sw, &val, TB_CFG_SWITCH, ROUTER_CS_5, 1);
+	if (ret)
+		return ret;
+
+	val |= ROUTER_CS_5_CV;
+
+	ret = tb_sw_write(sw, &val, TB_CFG_SWITCH, ROUTER_CS_5, 1);
+	if (ret)
+		return ret;
+
+	return tb_switch_wait_for_bit(sw, ROUTER_CS_6, ROUTER_CS_6_CR,
+				      ROUTER_CS_6_CR, 50);
+}
+
+/**
+ * usb4_switch_read_uid() - Read UID from USB4 router
+ * @sw: USB4 router
+ * @uid: UID is stored here
+ *
+ * Reads 64-bit UID from USB4 router config space.
+ */
+int usb4_switch_read_uid(struct tb_switch *sw, u64 *uid)
+{
+	return tb_sw_read(sw, uid, TB_CFG_SWITCH, ROUTER_CS_7, 2);
+}
+
+static int usb4_switch_drom_read_block(void *data,
+				       unsigned int dwaddress, void *buf,
+				       size_t dwords)
+{
+	struct tb_switch *sw = data;
+	u8 status = 0;
+	u32 metadata;
+	int ret;
+
+	metadata = (dwords << USB4_DROM_SIZE_SHIFT) & USB4_DROM_SIZE_MASK;
+	metadata |= (dwaddress << USB4_DROM_ADDRESS_SHIFT) &
+		USB4_DROM_ADDRESS_MASK;
+
+	ret = usb4_switch_op_data(sw, USB4_SWITCH_OP_DROM_READ, &metadata,
+				  &status, NULL, 0, buf, dwords);
+	if (ret)
+		return ret;
+
+	return status ? -EIO : 0;
+}
+
+/**
+ * usb4_switch_drom_read() - Read arbitrary bytes from USB4 router DROM
+ * @sw: USB4 router
+ * @address: Byte address inside DROM to start reading
+ * @buf: Buffer where the DROM content is stored
+ * @size: Number of bytes to read from DROM
+ *
+ * Uses USB4 router operations to read router DROM. For devices this
+ * should always work but for hosts it may return %-EOPNOTSUPP in which
+ * case the host router does not have DROM.
+ */
+int usb4_switch_drom_read(struct tb_switch *sw, unsigned int address, void *buf,
+			  size_t size)
+{
+	return tb_nvm_read_data(address, buf, size, USB4_DATA_RETRIES,
+				usb4_switch_drom_read_block, sw);
+}
+
+/**
+ * usb4_switch_lane_bonding_possible() - Are conditions met for lane bonding
+ * @sw: USB4 router
+ *
+ * Checks whether conditions are met so that lane bonding can be
+ * established with the upstream router. Call only for device routers.
+ */
+bool usb4_switch_lane_bonding_possible(struct tb_switch *sw)
+{
+	struct tb_port *up;
+	int ret;
+	u32 val;
+
+	up = tb_upstream_port(sw);
+	ret = tb_port_read(up, &val, TB_CFG_PORT, up->cap_usb4 + PORT_CS_18, 1);
+	if (ret)
+		return false;
+
+	return !!(val & PORT_CS_18_BE);
+}
+
+/**
+ * usb4_switch_set_wake() - Enabled/disable wake
+ * @sw: USB4 router
+ * @flags: Wakeup flags (%0 to disable)
+ *
+ * Enables/disables router to wake up from sleep.
+ */
+int usb4_switch_set_wake(struct tb_switch *sw, unsigned int flags)
+{
+	struct usb4_port *usb4;
+	struct tb_port *port;
+	u64 route = tb_route(sw);
+	u32 val;
+	int ret;
+
+	/*
+	 * Enable wakes coming from all USB4 downstream ports (from
+	 * child routers). For device routers do this also for the
+	 * upstream USB4 port.
+	 */
+	tb_switch_for_each_port(sw, port) {
+		if (!tb_port_is_null(port))
+			continue;
+		if (!route && tb_is_upstream_port(port))
+			continue;
+		if (!port->cap_usb4)
+			continue;
+
+		ret = tb_port_read(port, &val, TB_CFG_PORT,
+				   port->cap_usb4 + PORT_CS_19, 1);
+		if (ret)
+			return ret;
+
+		val &= ~(PORT_CS_19_WOC | PORT_CS_19_WOD | PORT_CS_19_WOU4);
+
+		if (tb_is_upstream_port(port)) {
+			val |= PORT_CS_19_WOU4;
+		} else {
+			bool configured = val & PORT_CS_19_PC;
+			usb4 = port->usb4;
+
+			if (((flags & TB_WAKE_ON_CONNECT) |
+			      device_may_wakeup(&usb4->dev)) && !configured)
+				val |= PORT_CS_19_WOC;
+			if (((flags & TB_WAKE_ON_DISCONNECT) |
+			      device_may_wakeup(&usb4->dev)) && configured)
+				val |= PORT_CS_19_WOD;
+			if ((flags & TB_WAKE_ON_USB4) && configured)
+				val |= PORT_CS_19_WOU4;
+		}
+
+		ret = tb_port_write(port, &val, TB_CFG_PORT,
+				    port->cap_usb4 + PORT_CS_19, 1);
+		if (ret)
+			return ret;
+	}
+
+	/*
+	 * Enable wakes from PCIe, USB 3.x and DP on this router. Only
+	 * needed for device routers.
+	 */
+	if (route) {
+		ret = tb_sw_read(sw, &val, TB_CFG_SWITCH, ROUTER_CS_5, 1);
+		if (ret)
+			return ret;
+
+		val &= ~(ROUTER_CS_5_WOP | ROUTER_CS_5_WOU | ROUTER_CS_5_WOD);
+		if (flags & TB_WAKE_ON_USB3)
+			val |= ROUTER_CS_5_WOU;
+		if (flags & TB_WAKE_ON_PCIE)
+			val |= ROUTER_CS_5_WOP;
+		if (flags & TB_WAKE_ON_DP)
+			val |= ROUTER_CS_5_WOD;
+
+		ret = tb_sw_write(sw, &val, TB_CFG_SWITCH, ROUTER_CS_5, 1);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+/**
+ * usb4_switch_set_sleep() - Prepare the router to enter sleep
+ * @sw: USB4 router
+ *
+ * Sets sleep bit for the router. Returns when the router sleep ready
+ * bit has been asserted.
+ */
+int usb4_switch_set_sleep(struct tb_switch *sw)
+{
+	int ret;
+	u32 val;
+
+	/* Set sleep bit and wait for sleep ready to be asserted */
+	ret = tb_sw_read(sw, &val, TB_CFG_SWITCH, ROUTER_CS_5, 1);
+	if (ret)
+		return ret;
+
+	val |= ROUTER_CS_5_SLP;
+
+	ret = tb_sw_write(sw, &val, TB_CFG_SWITCH, ROUTER_CS_5, 1);
+	if (ret)
+		return ret;
+
+	return tb_switch_wait_for_bit(sw, ROUTER_CS_6, ROUTER_CS_6_SLPR,
+				      ROUTER_CS_6_SLPR, 500);
+}
+
+/**
+ * usb4_switch_nvm_sector_size() - Return router NVM sector size
+ * @sw: USB4 router
+ *
+ * If the router supports NVM operations this function returns the NVM
+ * sector size in bytes. If NVM operations are not supported returns
+ * %-EOPNOTSUPP.
+ */
+int usb4_switch_nvm_sector_size(struct tb_switch *sw)
+{
+	u32 metadata;
+	u8 status;
+	int ret;
+
+	ret = usb4_switch_op(sw, USB4_SWITCH_OP_NVM_SECTOR_SIZE, &metadata,
+			     &status);
+	if (ret)
+		return ret;
+
+	if (status)
+		return status == 0x2 ? -EOPNOTSUPP : -EIO;
+
+	return metadata & USB4_NVM_SECTOR_SIZE_MASK;
+}
+
+static int usb4_switch_nvm_read_block(void *data,
+	unsigned int dwaddress, void *buf, size_t dwords)
+{
+	struct tb_switch *sw = data;
+	u8 status = 0;
+	u32 metadata;
+	int ret;
+
+	metadata = (dwords << USB4_NVM_READ_LENGTH_SHIFT) &
+		   USB4_NVM_READ_LENGTH_MASK;
+	metadata |= (dwaddress << USB4_NVM_READ_OFFSET_SHIFT) &
+		   USB4_NVM_READ_OFFSET_MASK;
+
+	ret = usb4_switch_op_data(sw, USB4_SWITCH_OP_NVM_READ, &metadata,
+				  &status, NULL, 0, buf, dwords);
+	if (ret)
+		return ret;
+
+	return status ? -EIO : 0;
+}
+
+/**
+ * usb4_switch_nvm_read() - Read arbitrary bytes from router NVM
+ * @sw: USB4 router
+ * @address: Starting address in bytes
+ * @buf: Read data is placed here
+ * @size: How many bytes to read
+ *
+ * Reads NVM contents of the router. If NVM is not supported returns
+ * %-EOPNOTSUPP.
+ */
+int usb4_switch_nvm_read(struct tb_switch *sw, unsigned int address, void *buf,
+			 size_t size)
+{
+	return tb_nvm_read_data(address, buf, size, USB4_DATA_RETRIES,
+				usb4_switch_nvm_read_block, sw);
+}
+
+/**
+ * usb4_switch_nvm_set_offset() - Set NVM write offset
+ * @sw: USB4 router
+ * @address: Start offset
+ *
+ * Explicitly sets NVM write offset. Normally when writing to NVM this
+ * is done automatically by usb4_switch_nvm_write().
+ *
+ * Returns %0 in success and negative errno if there was a failure.
+ */
+int usb4_switch_nvm_set_offset(struct tb_switch *sw, unsigned int address)
+{
+	u32 metadata, dwaddress;
+	u8 status = 0;
+	int ret;
+
+	dwaddress = address / 4;
+	metadata = (dwaddress << USB4_NVM_SET_OFFSET_SHIFT) &
+		   USB4_NVM_SET_OFFSET_MASK;
+
+	ret = usb4_switch_op(sw, USB4_SWITCH_OP_NVM_SET_OFFSET, &metadata,
+			     &status);
+	if (ret)
+		return ret;
+
+	return status ? -EIO : 0;
+}
+
+static int usb4_switch_nvm_write_next_block(void *data, unsigned int dwaddress,
+					    const void *buf, size_t dwords)
+{
+	struct tb_switch *sw = data;
+	u8 status;
+	int ret;
+
+	ret = usb4_switch_op_data(sw, USB4_SWITCH_OP_NVM_WRITE, NULL, &status,
+				  buf, dwords, NULL, 0);
+	if (ret)
+		return ret;
+
+	return status ? -EIO : 0;
+}
+
+/**
+ * usb4_switch_nvm_write() - Write to the router NVM
+ * @sw: USB4 router
+ * @address: Start address where to write in bytes
+ * @buf: Pointer to the data to write
+ * @size: Size of @buf in bytes
+ *
+ * Writes @buf to the router NVM using USB4 router operations. If NVM
+ * write is not supported returns %-EOPNOTSUPP.
+ */
+int usb4_switch_nvm_write(struct tb_switch *sw, unsigned int address,
+			  const void *buf, size_t size)
+{
+	int ret;
+
+	ret = usb4_switch_nvm_set_offset(sw, address);
+	if (ret)
+		return ret;
+
+	return tb_nvm_write_data(address, buf, size, USB4_DATA_RETRIES,
+				 usb4_switch_nvm_write_next_block, sw);
+}
+
+/**
+ * usb4_switch_nvm_authenticate() - Authenticate new NVM
+ * @sw: USB4 router
+ *
+ * After the new NVM has been written via usb4_switch_nvm_write(), this
+ * function triggers NVM authentication process. The router gets power
+ * cycled and if the authentication is successful the new NVM starts
+ * running. In case of failure returns negative errno.
+ *
+ * The caller should call usb4_switch_nvm_authenticate_status() to read
+ * the status of the authentication after power cycle. It should be the
+ * first router operation to avoid the status being lost.
+ */
+int usb4_switch_nvm_authenticate(struct tb_switch *sw)
+{
+	int ret;
+
+	ret = usb4_switch_op(sw, USB4_SWITCH_OP_NVM_AUTH, NULL, NULL);
+	switch (ret) {
+	/*
+	 * The router is power cycled once NVM_AUTH is started so it is
+	 * expected to get any of the following errors back.
+	 */
+	case -EACCES:
+	case -ENOTCONN:
+	case -ETIMEDOUT:
+		return 0;
+
+	default:
+		return ret;
+	}
+}
+
+/**
+ * usb4_switch_nvm_authenticate_status() - Read status of last NVM authenticate
+ * @sw: USB4 router
+ * @status: Status code of the operation
+ *
+ * The function checks if there is status available from the last NVM
+ * authenticate router operation. If there is status then %0 is returned
+ * and the status code is placed in @status. Returns negative errno in case
+ * of failure.
+ *
+ * Must be called before any other router operation.
+ */
+int usb4_switch_nvm_authenticate_status(struct tb_switch *sw, u32 *status)
+{
+	const struct tb_cm_ops *cm_ops = sw->tb->cm_ops;
+	u16 opcode;
+	u32 val;
+	int ret;
+
+	if (cm_ops->usb4_switch_nvm_authenticate_status) {
+		ret = cm_ops->usb4_switch_nvm_authenticate_status(sw, status);
+		if (ret != -EOPNOTSUPP)
+			return ret;
+	}
+
+	ret = tb_sw_read(sw, &val, TB_CFG_SWITCH, ROUTER_CS_26, 1);
+	if (ret)
+		return ret;
+
+	/* Check that the opcode is correct */
+	opcode = val & ROUTER_CS_26_OPCODE_MASK;
+	if (opcode == USB4_SWITCH_OP_NVM_AUTH) {
+		if (val & ROUTER_CS_26_OV)
+			return -EBUSY;
+		if (val & ROUTER_CS_26_ONS)
+			return -EOPNOTSUPP;
+
+		*status = (val & ROUTER_CS_26_STATUS_MASK) >>
+			ROUTER_CS_26_STATUS_SHIFT;
+	} else {
+		*status = 0;
+	}
+
+	return 0;
+}
+
+/**
+ * usb4_switch_credits_init() - Read buffer allocation parameters
+ * @sw: USB4 router
+ *
+ * Reads @sw buffer allocation parameters and initializes @sw buffer
+ * allocation fields accordingly. Specifically @sw->credits_allocation
+ * is set to %true if these parameters can be used in tunneling.
+ *
+ * Returns %0 on success and negative errno otherwise.
+ */
+int usb4_switch_credits_init(struct tb_switch *sw)
+{
+	int max_usb3, min_dp_aux, min_dp_main, max_pcie, max_dma;
+	int ret, length, i, nports;
+	const struct tb_port *port;
+	u32 data[USB4_DATA_DWORDS];
+	u32 metadata = 0;
+	u8 status = 0;
+
+	memset(data, 0, sizeof(data));
+	ret = usb4_switch_op_data(sw, USB4_SWITCH_OP_BUFFER_ALLOC, &metadata,
+				  &status, NULL, 0, data, ARRAY_SIZE(data));
+	if (ret)
+		return ret;
+	if (status)
+		return -EIO;
+
+	length = metadata & USB4_BA_LENGTH_MASK;
+	if (WARN_ON(length > ARRAY_SIZE(data)))
+		return -EMSGSIZE;
+
+	max_usb3 = -1;
+	min_dp_aux = -1;
+	min_dp_main = -1;
+	max_pcie = -1;
+	max_dma = -1;
+
+	tb_sw_dbg(sw, "credit allocation parameters:\n");
+
+	for (i = 0; i < length; i++) {
+		u16 index, value;
+
+		index = data[i] & USB4_BA_INDEX_MASK;
+		value = (data[i] & USB4_BA_VALUE_MASK) >> USB4_BA_VALUE_SHIFT;
+
+		switch (index) {
+		case USB4_BA_MAX_USB3:
+			tb_sw_dbg(sw, " USB3: %u\n", value);
+			max_usb3 = value;
+			break;
+		case USB4_BA_MIN_DP_AUX:
+			tb_sw_dbg(sw, " DP AUX: %u\n", value);
+			min_dp_aux = value;
+			break;
+		case USB4_BA_MIN_DP_MAIN:
+			tb_sw_dbg(sw, " DP main: %u\n", value);
+			min_dp_main = value;
+			break;
+		case USB4_BA_MAX_PCIE:
+			tb_sw_dbg(sw, " PCIe: %u\n", value);
+			max_pcie = value;
+			break;
+		case USB4_BA_MAX_HI:
+			tb_sw_dbg(sw, " DMA: %u\n", value);
+			max_dma = value;
+			break;
+		default:
+			tb_sw_dbg(sw, " unknown credit allocation index %#x, skipping\n",
+				  index);
+			break;
+		}
+	}
+
+	/*
+	 * Validate the buffer allocation preferences. If we find
+	 * issues, log a warning and fall back using the hard-coded
+	 * values.
+	 */
+
+	/* Host router must report baMaxHI */
+	if (!tb_route(sw) && max_dma < 0) {
+		tb_sw_warn(sw, "host router is missing baMaxHI\n");
+		goto err_invalid;
+	}
+
+	nports = 0;
+	tb_switch_for_each_port(sw, port) {
+		if (tb_port_is_null(port))
+			nports++;
+	}
+
+	/* Must have DP buffer allocation (multiple USB4 ports) */
+	if (nports > 2 && (min_dp_aux < 0 || min_dp_main < 0)) {
+		tb_sw_warn(sw, "multiple USB4 ports require baMinDPaux/baMinDPmain\n");
+		goto err_invalid;
+	}
+
+	tb_switch_for_each_port(sw, port) {
+		if (tb_port_is_dpout(port) && min_dp_main < 0) {
+			tb_sw_warn(sw, "missing baMinDPmain");
+			goto err_invalid;
+		}
+		if ((tb_port_is_dpin(port) || tb_port_is_dpout(port)) &&
+		    min_dp_aux < 0) {
+			tb_sw_warn(sw, "missing baMinDPaux");
+			goto err_invalid;
+		}
+		if ((tb_port_is_usb3_down(port) || tb_port_is_usb3_up(port)) &&
+		    max_usb3 < 0) {
+			tb_sw_warn(sw, "missing baMaxUSB3");
+			goto err_invalid;
+		}
+		if ((tb_port_is_pcie_down(port) || tb_port_is_pcie_up(port)) &&
+		    max_pcie < 0) {
+			tb_sw_warn(sw, "missing baMaxPCIe");
+			goto err_invalid;
+		}
+	}
+
+	/*
+	 * Buffer allocation passed the validation so we can use it in
+	 * path creation.
+	 */
+	sw->credit_allocation = true;
+	if (max_usb3 > 0)
+		sw->max_usb3_credits = max_usb3;
+	if (min_dp_aux > 0)
+		sw->min_dp_aux_credits = min_dp_aux;
+	if (min_dp_main > 0)
+		sw->min_dp_main_credits = min_dp_main;
+	if (max_pcie > 0)
+		sw->max_pcie_credits = max_pcie;
+	if (max_dma > 0)
+		sw->max_dma_credits = max_dma;
+
+	return 0;
+
+err_invalid:
+	return -EINVAL;
+}
+
+/**
+ * usb4_switch_query_dp_resource() - Query availability of DP IN resource
+ * @sw: USB4 router
+ * @in: DP IN adapter
+ *
+ * For DP tunneling this function can be used to query availability of
+ * DP IN resource. Returns true if the resource is available for DP
+ * tunneling, false otherwise.
+ */
+bool usb4_switch_query_dp_resource(struct tb_switch *sw, struct tb_port *in)
+{
+	u32 metadata = in->port;
+	u8 status;
+	int ret;
+
+	ret = usb4_switch_op(sw, USB4_SWITCH_OP_QUERY_DP_RESOURCE, &metadata,
+			     &status);
+	/*
+	 * If DP resource allocation is not supported assume it is
+	 * always available.
+	 */
+	if (ret == -EOPNOTSUPP)
+		return true;
+	if (ret)
+		return false;
+
+	return !status;
+}
+
+/**
+ * usb4_switch_alloc_dp_resource() - Allocate DP IN resource
+ * @sw: USB4 router
+ * @in: DP IN adapter
+ *
+ * Allocates DP IN resource for DP tunneling using USB4 router
+ * operations. If the resource was allocated returns %0. Otherwise
+ * returns negative errno, in particular %-EBUSY if the resource is
+ * already allocated.
+ */
+int usb4_switch_alloc_dp_resource(struct tb_switch *sw, struct tb_port *in)
+{
+	u32 metadata = in->port;
+	u8 status;
+	int ret;
+
+	ret = usb4_switch_op(sw, USB4_SWITCH_OP_ALLOC_DP_RESOURCE, &metadata,
+			     &status);
+	if (ret == -EOPNOTSUPP)
+		return 0;
+	if (ret)
+		return ret;
+
+	return status ? -EBUSY : 0;
+}
+
+/**
+ * usb4_switch_dealloc_dp_resource() - Releases allocated DP IN resource
+ * @sw: USB4 router
+ * @in: DP IN adapter
+ *
+ * Releases the previously allocated DP IN resource.
+ */
+int usb4_switch_dealloc_dp_resource(struct tb_switch *sw, struct tb_port *in)
+{
+	u32 metadata = in->port;
+	u8 status;
+	int ret;
+
+	ret = usb4_switch_op(sw, USB4_SWITCH_OP_DEALLOC_DP_RESOURCE, &metadata,
+			     &status);
+	if (ret == -EOPNOTSUPP)
+		return 0;
+	if (ret)
+		return ret;
+
+	return status ? -EIO : 0;
+}
+
+static int usb4_port_idx(const struct tb_switch *sw, const struct tb_port *port)
+{
+	struct tb_port *p;
+	int usb4_idx = 0;
+
+	/* Assume port is primary */
+	tb_switch_for_each_port(sw, p) {
+		if (!tb_port_is_null(p))
+			continue;
+		if (tb_is_upstream_port(p))
+			continue;
+		if (!p->link_nr) {
+			if (p == port)
+				break;
+			usb4_idx++;
+		}
+	}
+
+	return usb4_idx;
+}
+
+/**
+ * usb4_switch_map_pcie_down() - Map USB4 port to a PCIe downstream adapter
+ * @sw: USB4 router
+ * @port: USB4 port
+ *
+ * USB4 routers have direct mapping between USB4 ports and PCIe
+ * downstream adapters where the PCIe topology is extended. This
+ * function returns the corresponding downstream PCIe adapter or %NULL
+ * if no such mapping was possible.
+ */
+struct tb_port *usb4_switch_map_pcie_down(struct tb_switch *sw,
+					  const struct tb_port *port)
+{
+	int usb4_idx = usb4_port_idx(sw, port);
+	struct tb_port *p;
+	int pcie_idx = 0;
+
+	/* Find PCIe down port matching usb4_port */
+	tb_switch_for_each_port(sw, p) {
+		if (!tb_port_is_pcie_down(p))
+			continue;
+
+		if (pcie_idx == usb4_idx)
+			return p;
+
+		pcie_idx++;
+	}
+
+	return NULL;
+}
+
+/**
+ * usb4_switch_map_usb3_down() - Map USB4 port to a USB3 downstream adapter
+ * @sw: USB4 router
+ * @port: USB4 port
+ *
+ * USB4 routers have direct mapping between USB4 ports and USB 3.x
+ * downstream adapters where the USB 3.x topology is extended. This
+ * function returns the corresponding downstream USB 3.x adapter or
+ * %NULL if no such mapping was possible.
+ */
+struct tb_port *usb4_switch_map_usb3_down(struct tb_switch *sw,
+					  const struct tb_port *port)
+{
+	int usb4_idx = usb4_port_idx(sw, port);
+	struct tb_port *p;
+	int usb_idx = 0;
+
+	/* Find USB3 down port matching usb4_port */
+	tb_switch_for_each_port(sw, p) {
+		if (!tb_port_is_usb3_down(p))
+			continue;
+
+		if (usb_idx == usb4_idx)
+			return p;
+
+		usb_idx++;
+	}
+
+	return NULL;
+}
+
+/**
+ * usb4_switch_add_ports() - Add USB4 ports for this router
+ * @sw: USB4 router
+ *
+ * For USB4 router finds all USB4 ports and registers devices for each.
+ * Can be called to any router.
+ *
+ * Return %0 in case of success and negative errno in case of failure.
+ */
+int usb4_switch_add_ports(struct tb_switch *sw)
+{
+	struct tb_port *port;
+
+	if (tb_switch_is_icm(sw) || !tb_switch_is_usb4(sw))
+		return 0;
+
+	tb_switch_for_each_port(sw, port) {
+		struct usb4_port *usb4;
+
+		if (!tb_port_is_null(port))
+			continue;
+		if (!port->cap_usb4)
+			continue;
+
+		usb4 = usb4_port_device_add(port);
+		if (IS_ERR(usb4)) {
+			usb4_switch_remove_ports(sw);
+			return PTR_ERR(usb4);
+		}
+
+		port->usb4 = usb4;
+	}
+
+	return 0;
+}
+
+/**
+ * usb4_switch_remove_ports() - Removes USB4 ports from this router
+ * @sw: USB4 router
+ *
+ * Unregisters previously registered USB4 ports.
+ */
+void usb4_switch_remove_ports(struct tb_switch *sw)
+{
+	struct tb_port *port;
+
+	tb_switch_for_each_port(sw, port) {
+		if (port->usb4) {
+			usb4_port_device_remove(port->usb4);
+			port->usb4 = NULL;
+		}
+	}
+}
+
+/**
+ * usb4_port_unlock() - Unlock USB4 downstream port
+ * @port: USB4 port to unlock
+ *
+ * Unlocks USB4 downstream port so that the connection manager can
+ * access the router below this port.
+ */
+int usb4_port_unlock(struct tb_port *port)
+{
+	int ret;
+	u32 val;
+
+	ret = tb_port_read(port, &val, TB_CFG_PORT, ADP_CS_4, 1);
+	if (ret)
+		return ret;
+
+	val &= ~ADP_CS_4_LCK;
+	return tb_port_write(port, &val, TB_CFG_PORT, ADP_CS_4, 1);
+}
+
+/**
+ * usb4_port_hotplug_enable() - Enables hotplug for a port
+ * @port: USB4 port to operate on
+ *
+ * Enables hot plug events on a given port. This is only intended
+ * to be used on lane, DP-IN, and DP-OUT adapters.
+ */
+int usb4_port_hotplug_enable(struct tb_port *port)
+{
+	int ret;
+	u32 val;
+
+	ret = tb_port_read(port, &val, TB_CFG_PORT, ADP_CS_5, 1);
+	if (ret)
+		return ret;
+
+	val &= ~ADP_CS_5_DHP;
+	return tb_port_write(port, &val, TB_CFG_PORT, ADP_CS_5, 1);
+}
+
+static int usb4_port_set_configured(struct tb_port *port, bool configured)
+{
+	int ret;
+	u32 val;
+
+	if (!port->cap_usb4)
+		return -EINVAL;
+
+	ret = tb_port_read(port, &val, TB_CFG_PORT,
+			   port->cap_usb4 + PORT_CS_19, 1);
+	if (ret)
+		return ret;
+
+	if (configured)
+		val |= PORT_CS_19_PC;
+	else
+		val &= ~PORT_CS_19_PC;
+
+	return tb_port_write(port, &val, TB_CFG_PORT,
+			     port->cap_usb4 + PORT_CS_19, 1);
+}
+
+/**
+ * usb4_port_configure() - Set USB4 port configured
+ * @port: USB4 router
+ *
+ * Sets the USB4 link to be configured for power management purposes.
+ */
+int usb4_port_configure(struct tb_port *port)
+{
+	return usb4_port_set_configured(port, true);
+}
+
+/**
+ * usb4_port_unconfigure() - Set USB4 port unconfigured
+ * @port: USB4 router
+ *
+ * Sets the USB4 link to be unconfigured for power management purposes.
+ */
+void usb4_port_unconfigure(struct tb_port *port)
+{
+	usb4_port_set_configured(port, false);
+}
+
+static int usb4_set_xdomain_configured(struct tb_port *port, bool configured)
+{
+	int ret;
+	u32 val;
+
+	if (!port->cap_usb4)
+		return -EINVAL;
+
+	ret = tb_port_read(port, &val, TB_CFG_PORT,
+			   port->cap_usb4 + PORT_CS_19, 1);
+	if (ret)
+		return ret;
+
+	if (configured)
+		val |= PORT_CS_19_PID;
+	else
+		val &= ~PORT_CS_19_PID;
+
+	return tb_port_write(port, &val, TB_CFG_PORT,
+			     port->cap_usb4 + PORT_CS_19, 1);
+}
+
+/**
+ * usb4_port_configure_xdomain() - Configure port for XDomain
+ * @port: USB4 port connected to another host
+ * @xd: XDomain that is connected to the port
+ *
+ * Marks the USB4 port as being connected to another host and updates
+ * the link type. Returns %0 in success and negative errno in failure.
+ */
+int usb4_port_configure_xdomain(struct tb_port *port, struct tb_xdomain *xd)
+{
+	xd->link_usb4 = link_is_usb4(port);
+	return usb4_set_xdomain_configured(port, true);
+}
+
+/**
+ * usb4_port_unconfigure_xdomain() - Unconfigure port for XDomain
+ * @port: USB4 port that was connected to another host
+ *
+ * Clears USB4 port from being marked as XDomain.
+ */
+void usb4_port_unconfigure_xdomain(struct tb_port *port)
+{
+	usb4_set_xdomain_configured(port, false);
+}
+
+static int usb4_port_wait_for_bit(struct tb_port *port, u32 offset, u32 bit,
+				  u32 value, int timeout_msec)
+{
+	ktime_t timeout = ktime_add_ms(ktime_get(), timeout_msec);
+
+	do {
+		u32 val;
+		int ret;
+
+		ret = tb_port_read(port, &val, TB_CFG_PORT, offset, 1);
+		if (ret)
+			return ret;
+
+		if ((val & bit) == value)
+			return 0;
+
+		usleep_range(50, 100);
+	} while (ktime_before(ktime_get(), timeout));
+
+	return -ETIMEDOUT;
+}
+
+static int usb4_port_read_data(struct tb_port *port, void *data, size_t dwords)
+{
+	if (dwords > USB4_DATA_DWORDS)
+		return -EINVAL;
+
+	return tb_port_read(port, data, TB_CFG_PORT, port->cap_usb4 + PORT_CS_2,
+			    dwords);
+}
+
+static int usb4_port_write_data(struct tb_port *port, const void *data,
+				size_t dwords)
+{
+	if (dwords > USB4_DATA_DWORDS)
+		return -EINVAL;
+
+	return tb_port_write(port, data, TB_CFG_PORT, port->cap_usb4 + PORT_CS_2,
+			     dwords);
+}
+
+static int usb4_port_sb_read(struct tb_port *port, enum usb4_sb_target target,
+			     u8 index, u8 reg, void *buf, u8 size)
+{
+	size_t dwords = DIV_ROUND_UP(size, 4);
+	int ret;
+	u32 val;
+
+	if (!port->cap_usb4)
+		return -EINVAL;
+
+	val = reg;
+	val |= size << PORT_CS_1_LENGTH_SHIFT;
+	val |= (target << PORT_CS_1_TARGET_SHIFT) & PORT_CS_1_TARGET_MASK;
+	if (target == USB4_SB_TARGET_RETIMER)
+		val |= (index << PORT_CS_1_RETIMER_INDEX_SHIFT);
+	val |= PORT_CS_1_PND;
+
+	ret = tb_port_write(port, &val, TB_CFG_PORT,
+			    port->cap_usb4 + PORT_CS_1, 1);
+	if (ret)
+		return ret;
+
+	ret = usb4_port_wait_for_bit(port, port->cap_usb4 + PORT_CS_1,
+				     PORT_CS_1_PND, 0, 500);
+	if (ret)
+		return ret;
+
+	ret = tb_port_read(port, &val, TB_CFG_PORT,
+			    port->cap_usb4 + PORT_CS_1, 1);
+	if (ret)
+		return ret;
+
+	if (val & PORT_CS_1_NR)
+		return -ENODEV;
+	if (val & PORT_CS_1_RC)
+		return -EIO;
+
+	return buf ? usb4_port_read_data(port, buf, dwords) : 0;
+}
+
+static int usb4_port_sb_write(struct tb_port *port, enum usb4_sb_target target,
+			      u8 index, u8 reg, const void *buf, u8 size)
+{
+	size_t dwords = DIV_ROUND_UP(size, 4);
+	int ret;
+	u32 val;
+
+	if (!port->cap_usb4)
+		return -EINVAL;
+
+	if (buf) {
+		ret = usb4_port_write_data(port, buf, dwords);
+		if (ret)
+			return ret;
+	}
+
+	val = reg;
+	val |= size << PORT_CS_1_LENGTH_SHIFT;
+	val |= PORT_CS_1_WNR_WRITE;
+	val |= (target << PORT_CS_1_TARGET_SHIFT) & PORT_CS_1_TARGET_MASK;
+	if (target == USB4_SB_TARGET_RETIMER)
+		val |= (index << PORT_CS_1_RETIMER_INDEX_SHIFT);
+	val |= PORT_CS_1_PND;
+
+	ret = tb_port_write(port, &val, TB_CFG_PORT,
+			    port->cap_usb4 + PORT_CS_1, 1);
+	if (ret)
+		return ret;
+
+	ret = usb4_port_wait_for_bit(port, port->cap_usb4 + PORT_CS_1,
+				     PORT_CS_1_PND, 0, 500);
+	if (ret)
+		return ret;
+
+	ret = tb_port_read(port, &val, TB_CFG_PORT,
+			    port->cap_usb4 + PORT_CS_1, 1);
+	if (ret)
+		return ret;
+
+	if (val & PORT_CS_1_NR)
+		return -ENODEV;
+	if (val & PORT_CS_1_RC)
+		return -EIO;
+
+	return 0;
+}
+
+static int usb4_port_sb_opcode_err_to_errno(u32 val)
+{
+	switch (val) {
+	case 0:
+		return 0;
+	case USB4_SB_OPCODE_ERR:
+		return -EAGAIN;
+	case USB4_SB_OPCODE_ONS:
+		return -EOPNOTSUPP;
+	default:
+		return -EIO;
+	}
+}
+
+static int usb4_port_sb_op(struct tb_port *port, enum usb4_sb_target target,
+			   u8 index, enum usb4_sb_opcode opcode, int timeout_msec)
+{
+	ktime_t timeout;
+	u32 val;
+	int ret;
+
+	val = opcode;
+	ret = usb4_port_sb_write(port, target, index, USB4_SB_OPCODE, &val,
+				 sizeof(val));
+	if (ret)
+		return ret;
+
+	timeout = ktime_add_ms(ktime_get(), timeout_msec);
+
+	do {
+		/* Check results */
+		ret = usb4_port_sb_read(port, target, index, USB4_SB_OPCODE,
+					&val, sizeof(val));
+		if (ret)
+			return ret;
+
+		if (val != opcode)
+			return usb4_port_sb_opcode_err_to_errno(val);
+	} while (ktime_before(ktime_get(), timeout));
+
+	return -ETIMEDOUT;
+}
+
+static int usb4_port_set_router_offline(struct tb_port *port, bool offline)
+{
+	u32 val = !offline;
+	int ret;
+
+	ret = usb4_port_sb_write(port, USB4_SB_TARGET_ROUTER, 0,
+				  USB4_SB_METADATA, &val, sizeof(val));
+	if (ret)
+		return ret;
+
+	val = USB4_SB_OPCODE_ROUTER_OFFLINE;
+	return usb4_port_sb_write(port, USB4_SB_TARGET_ROUTER, 0,
+				  USB4_SB_OPCODE, &val, sizeof(val));
+}
+
+/**
+ * usb4_port_router_offline() - Put the USB4 port to offline mode
+ * @port: USB4 port
+ *
+ * This function puts the USB4 port into offline mode. In this mode the
+ * port does not react on hotplug events anymore. This needs to be
+ * called before retimer access is done when the USB4 links is not up.
+ *
+ * Returns %0 in case of success and negative errno if there was an
+ * error.
+ */
+int usb4_port_router_offline(struct tb_port *port)
+{
+	return usb4_port_set_router_offline(port, true);
+}
+
+/**
+ * usb4_port_router_online() - Put the USB4 port back to online
+ * @port: USB4 port
+ *
+ * Makes the USB4 port functional again.
+ */
+int usb4_port_router_online(struct tb_port *port)
+{
+	return usb4_port_set_router_offline(port, false);
+}
+
+/**
+ * usb4_port_enumerate_retimers() - Send RT broadcast transaction
+ * @port: USB4 port
+ *
+ * This forces the USB4 port to send broadcast RT transaction which
+ * makes the retimers on the link to assign index to themselves. Returns
+ * %0 in case of success and negative errno if there was an error.
+ */
+int usb4_port_enumerate_retimers(struct tb_port *port)
+{
+	u32 val;
+
+	val = USB4_SB_OPCODE_ENUMERATE_RETIMERS;
+	return usb4_port_sb_write(port, USB4_SB_TARGET_ROUTER, 0,
+				  USB4_SB_OPCODE, &val, sizeof(val));
+}
+
+/**
+ * usb4_port_clx_supported() - Check if CLx is supported by the link
+ * @port: Port to check for CLx support for
+ *
+ * PORT_CS_18_CPS bit reflects if the link supports CLx including
+ * active cables (if connected on the link).
+ */
+bool usb4_port_clx_supported(struct tb_port *port)
+{
+	int ret;
+	u32 val;
+
+	ret = tb_port_read(port, &val, TB_CFG_PORT,
+			   port->cap_usb4 + PORT_CS_18, 1);
+	if (ret)
+		return false;
+
+	return !!(val & PORT_CS_18_CPS);
+}
+
+/**
+ * usb4_port_margining_caps() - Read USB4 port marginig capabilities
+ * @port: USB4 port
+ * @caps: Array with at least two elements to hold the results
+ *
+ * Reads the USB4 port lane margining capabilities into @caps.
+ */
+int usb4_port_margining_caps(struct tb_port *port, u32 *caps)
+{
+	int ret;
+
+	ret = usb4_port_sb_op(port, USB4_SB_TARGET_ROUTER, 0,
+			      USB4_SB_OPCODE_READ_LANE_MARGINING_CAP, 500);
+	if (ret)
+		return ret;
+
+	return usb4_port_sb_read(port, USB4_SB_TARGET_ROUTER, 0,
+				 USB4_SB_DATA, caps, sizeof(*caps) * 2);
+}
+
+/**
+ * usb4_port_hw_margin() - Run hardware lane margining on port
+ * @port: USB4 port
+ * @lanes: Which lanes to run (must match the port capabilities). Can be
+ *	   %0, %1 or %7.
+ * @ber_level: BER level contour value
+ * @timing: Perform timing margining instead of voltage
+ * @right_high: Use Right/high margin instead of left/low
+ * @results: Array with at least two elements to hold the results
+ *
+ * Runs hardware lane margining on USB4 port and returns the result in
+ * @results.
+ */
+int usb4_port_hw_margin(struct tb_port *port, unsigned int lanes,
+			unsigned int ber_level, bool timing, bool right_high,
+			u32 *results)
+{
+	u32 val;
+	int ret;
+
+	val = lanes;
+	if (timing)
+		val |= USB4_MARGIN_HW_TIME;
+	if (right_high)
+		val |= USB4_MARGIN_HW_RH;
+	if (ber_level)
+		val |= (ber_level << USB4_MARGIN_HW_BER_SHIFT) &
+			USB4_MARGIN_HW_BER_MASK;
+
+	ret = usb4_port_sb_write(port, USB4_SB_TARGET_ROUTER, 0,
+				 USB4_SB_METADATA, &val, sizeof(val));
+	if (ret)
+		return ret;
+
+	ret = usb4_port_sb_op(port, USB4_SB_TARGET_ROUTER, 0,
+			      USB4_SB_OPCODE_RUN_HW_LANE_MARGINING, 2500);
+	if (ret)
+		return ret;
+
+	return usb4_port_sb_read(port, USB4_SB_TARGET_ROUTER, 0,
+				 USB4_SB_DATA, results, sizeof(*results) * 2);
+}
+
+/**
+ * usb4_port_sw_margin() - Run software lane margining on port
+ * @port: USB4 port
+ * @lanes: Which lanes to run (must match the port capabilities). Can be
+ *	   %0, %1 or %7.
+ * @timing: Perform timing margining instead of voltage
+ * @right_high: Use Right/high margin instead of left/low
+ * @counter: What to do with the error counter
+ *
+ * Runs software lane margining on USB4 port. Read back the error
+ * counters by calling usb4_port_sw_margin_errors(). Returns %0 in
+ * success and negative errno otherwise.
+ */
+int usb4_port_sw_margin(struct tb_port *port, unsigned int lanes, bool timing,
+			bool right_high, u32 counter)
+{
+	u32 val;
+	int ret;
+
+	val = lanes;
+	if (timing)
+		val |= USB4_MARGIN_SW_TIME;
+	if (right_high)
+		val |= USB4_MARGIN_SW_RH;
+	val |= (counter << USB4_MARGIN_SW_COUNTER_SHIFT) &
+		USB4_MARGIN_SW_COUNTER_MASK;
+
+	ret = usb4_port_sb_write(port, USB4_SB_TARGET_ROUTER, 0,
+				 USB4_SB_METADATA, &val, sizeof(val));
+	if (ret)
+		return ret;
+
+	return usb4_port_sb_op(port, USB4_SB_TARGET_ROUTER, 0,
+			       USB4_SB_OPCODE_RUN_SW_LANE_MARGINING, 2500);
+}
+
+/**
+ * usb4_port_sw_margin_errors() - Read the software margining error counters
+ * @port: USB4 port
+ * @errors: Error metadata is copied here.
+ *
+ * This reads back the software margining error counters from the port.
+ * Returns %0 in success and negative errno otherwise.
+ */
+int usb4_port_sw_margin_errors(struct tb_port *port, u32 *errors)
+{
+	int ret;
+
+	ret = usb4_port_sb_op(port, USB4_SB_TARGET_ROUTER, 0,
+			      USB4_SB_OPCODE_READ_SW_MARGIN_ERR, 150);
+	if (ret)
+		return ret;
+
+	return usb4_port_sb_read(port, USB4_SB_TARGET_ROUTER, 0,
+				 USB4_SB_METADATA, errors, sizeof(*errors));
+}
+
+static inline int usb4_port_retimer_op(struct tb_port *port, u8 index,
+				       enum usb4_sb_opcode opcode,
+				       int timeout_msec)
+{
+	return usb4_port_sb_op(port, USB4_SB_TARGET_RETIMER, index, opcode,
+			       timeout_msec);
+}
+
+/**
+ * usb4_port_retimer_set_inbound_sbtx() - Enable sideband channel transactions
+ * @port: USB4 port
+ * @index: Retimer index
+ *
+ * Enables sideband channel transations on SBTX. Can be used when USB4
+ * link does not go up, for example if there is no device connected.
+ */
+int usb4_port_retimer_set_inbound_sbtx(struct tb_port *port, u8 index)
+{
+	int ret;
+
+	ret = usb4_port_retimer_op(port, index, USB4_SB_OPCODE_SET_INBOUND_SBTX,
+				   500);
+
+	if (ret != -ENODEV)
+		return ret;
+
+	/*
+	 * Per the USB4 retimer spec, the retimer is not required to
+	 * send an RT (Retimer Transaction) response for the first
+	 * SET_INBOUND_SBTX command
+	 */
+	return usb4_port_retimer_op(port, index, USB4_SB_OPCODE_SET_INBOUND_SBTX,
+				    500);
+}
+
+/**
+ * usb4_port_retimer_unset_inbound_sbtx() - Disable sideband channel transactions
+ * @port: USB4 port
+ * @index: Retimer index
+ *
+ * Disables sideband channel transations on SBTX. The reverse of
+ * usb4_port_retimer_set_inbound_sbtx().
+ */
+int usb4_port_retimer_unset_inbound_sbtx(struct tb_port *port, u8 index)
+{
+	return usb4_port_retimer_op(port, index,
+				    USB4_SB_OPCODE_UNSET_INBOUND_SBTX, 500);
+}
+
+/**
+ * usb4_port_retimer_read() - Read from retimer sideband registers
+ * @port: USB4 port
+ * @index: Retimer index
+ * @reg: Sideband register to read
+ * @buf: Data from @reg is stored here
+ * @size: Number of bytes to read
+ *
+ * Function reads retimer sideband registers starting from @reg. The
+ * retimer is connected to @port at @index. Returns %0 in case of
+ * success, and read data is copied to @buf. If there is no retimer
+ * present at given @index returns %-ENODEV. In any other failure
+ * returns negative errno.
+ */
+int usb4_port_retimer_read(struct tb_port *port, u8 index, u8 reg, void *buf,
+			   u8 size)
+{
+	return usb4_port_sb_read(port, USB4_SB_TARGET_RETIMER, index, reg, buf,
+				 size);
+}
+
+/**
+ * usb4_port_retimer_write() - Write to retimer sideband registers
+ * @port: USB4 port
+ * @index: Retimer index
+ * @reg: Sideband register to write
+ * @buf: Data that is written starting from @reg
+ * @size: Number of bytes to write
+ *
+ * Writes retimer sideband registers starting from @reg. The retimer is
+ * connected to @port at @index. Returns %0 in case of success. If there
+ * is no retimer present at given @index returns %-ENODEV. In any other
+ * failure returns negative errno.
+ */
+int usb4_port_retimer_write(struct tb_port *port, u8 index, u8 reg,
+			    const void *buf, u8 size)
+{
+	return usb4_port_sb_write(port, USB4_SB_TARGET_RETIMER, index, reg, buf,
+				  size);
+}
+
+/**
+ * usb4_port_retimer_is_last() - Is the retimer last on-board retimer
+ * @port: USB4 port
+ * @index: Retimer index
+ *
+ * If the retimer at @index is last one (connected directly to the
+ * Type-C port) this function returns %1. If it is not returns %0. If
+ * the retimer is not present returns %-ENODEV. Otherwise returns
+ * negative errno.
+ */
+int usb4_port_retimer_is_last(struct tb_port *port, u8 index)
+{
+	u32 metadata;
+	int ret;
+
+	ret = usb4_port_retimer_op(port, index, USB4_SB_OPCODE_QUERY_LAST_RETIMER,
+				   500);
+	if (ret)
+		return ret;
+
+	ret = usb4_port_retimer_read(port, index, USB4_SB_METADATA, &metadata,
+				     sizeof(metadata));
+	return ret ? ret : metadata & 1;
+}
+
+/**
+ * usb4_port_retimer_nvm_sector_size() - Read retimer NVM sector size
+ * @port: USB4 port
+ * @index: Retimer index
+ *
+ * Reads NVM sector size (in bytes) of a retimer at @index. This
+ * operation can be used to determine whether the retimer supports NVM
+ * upgrade for example. Returns sector size in bytes or negative errno
+ * in case of error. Specifically returns %-ENODEV if there is no
+ * retimer at @index.
+ */
+int usb4_port_retimer_nvm_sector_size(struct tb_port *port, u8 index)
+{
+	u32 metadata;
+	int ret;
+
+	ret = usb4_port_retimer_op(port, index, USB4_SB_OPCODE_GET_NVM_SECTOR_SIZE,
+				   500);
+	if (ret)
+		return ret;
+
+	ret = usb4_port_retimer_read(port, index, USB4_SB_METADATA, &metadata,
+				     sizeof(metadata));
+	return ret ? ret : metadata & USB4_NVM_SECTOR_SIZE_MASK;
+}
+
+/**
+ * usb4_port_retimer_nvm_set_offset() - Set NVM write offset
+ * @port: USB4 port
+ * @index: Retimer index
+ * @address: Start offset
+ *
+ * Exlicitly sets NVM write offset. Normally when writing to NVM this is
+ * done automatically by usb4_port_retimer_nvm_write().
+ *
+ * Returns %0 in success and negative errno if there was a failure.
+ */
+int usb4_port_retimer_nvm_set_offset(struct tb_port *port, u8 index,
+				     unsigned int address)
+{
+	u32 metadata, dwaddress;
+	int ret;
+
+	dwaddress = address / 4;
+	metadata = (dwaddress << USB4_NVM_SET_OFFSET_SHIFT) &
+		  USB4_NVM_SET_OFFSET_MASK;
+
+	ret = usb4_port_retimer_write(port, index, USB4_SB_METADATA, &metadata,
+				      sizeof(metadata));
+	if (ret)
+		return ret;
+
+	return usb4_port_retimer_op(port, index, USB4_SB_OPCODE_NVM_SET_OFFSET,
+				    500);
+}
+
+struct retimer_info {
+	struct tb_port *port;
+	u8 index;
+};
+
+static int usb4_port_retimer_nvm_write_next_block(void *data,
+	unsigned int dwaddress, const void *buf, size_t dwords)
+
+{
+	const struct retimer_info *info = data;
+	struct tb_port *port = info->port;
+	u8 index = info->index;
+	int ret;
+
+	ret = usb4_port_retimer_write(port, index, USB4_SB_DATA,
+				      buf, dwords * 4);
+	if (ret)
+		return ret;
+
+	return usb4_port_retimer_op(port, index,
+			USB4_SB_OPCODE_NVM_BLOCK_WRITE, 1000);
+}
+
+/**
+ * usb4_port_retimer_nvm_write() - Write to retimer NVM
+ * @port: USB4 port
+ * @index: Retimer index
+ * @address: Byte address where to start the write
+ * @buf: Data to write
+ * @size: Size in bytes how much to write
+ *
+ * Writes @size bytes from @buf to the retimer NVM. Used for NVM
+ * upgrade. Returns %0 if the data was written successfully and negative
+ * errno in case of failure. Specifically returns %-ENODEV if there is
+ * no retimer at @index.
+ */
+int usb4_port_retimer_nvm_write(struct tb_port *port, u8 index, unsigned int address,
+				const void *buf, size_t size)
+{
+	struct retimer_info info = { .port = port, .index = index };
+	int ret;
+
+	ret = usb4_port_retimer_nvm_set_offset(port, index, address);
+	if (ret)
+		return ret;
+
+	return tb_nvm_write_data(address, buf, size, USB4_DATA_RETRIES,
+				 usb4_port_retimer_nvm_write_next_block, &info);
+}
+
+/**
+ * usb4_port_retimer_nvm_authenticate() - Start retimer NVM upgrade
+ * @port: USB4 port
+ * @index: Retimer index
+ *
+ * After the new NVM image has been written via usb4_port_retimer_nvm_write()
+ * this function can be used to trigger the NVM upgrade process. If
+ * successful the retimer restarts with the new NVM and may not have the
+ * index set so one needs to call usb4_port_enumerate_retimers() to
+ * force index to be assigned.
+ */
+int usb4_port_retimer_nvm_authenticate(struct tb_port *port, u8 index)
+{
+	u32 val;
+
+	/*
+	 * We need to use the raw operation here because once the
+	 * authentication completes the retimer index is not set anymore
+	 * so we do not get back the status now.
+	 */
+	val = USB4_SB_OPCODE_NVM_AUTH_WRITE;
+	return usb4_port_sb_write(port, USB4_SB_TARGET_RETIMER, index,
+				  USB4_SB_OPCODE, &val, sizeof(val));
+}
+
+/**
+ * usb4_port_retimer_nvm_authenticate_status() - Read status of NVM upgrade
+ * @port: USB4 port
+ * @index: Retimer index
+ * @status: Raw status code read from metadata
+ *
+ * This can be called after usb4_port_retimer_nvm_authenticate() and
+ * usb4_port_enumerate_retimers() to fetch status of the NVM upgrade.
+ *
+ * Returns %0 if the authentication status was successfully read. The
+ * completion metadata (the result) is then stored into @status. If
+ * reading the status fails, returns negative errno.
+ */
+int usb4_port_retimer_nvm_authenticate_status(struct tb_port *port, u8 index,
+					      u32 *status)
+{
+	u32 metadata, val;
+	int ret;
+
+	ret = usb4_port_retimer_read(port, index, USB4_SB_OPCODE, &val,
+				     sizeof(val));
+	if (ret)
+		return ret;
+
+	ret = usb4_port_sb_opcode_err_to_errno(val);
+	switch (ret) {
+	case 0:
+		*status = 0;
+		return 0;
+
+	case -EAGAIN:
+		ret = usb4_port_retimer_read(port, index, USB4_SB_METADATA,
+					     &metadata, sizeof(metadata));
+		if (ret)
+			return ret;
+
+		*status = metadata & USB4_SB_METADATA_NVM_AUTH_WRITE_MASK;
+		return 0;
+
+	default:
+		return ret;
+	}
+}
+
+static int usb4_port_retimer_nvm_read_block(void *data, unsigned int dwaddress,
+					    void *buf, size_t dwords)
+{
+	const struct retimer_info *info = data;
+	struct tb_port *port = info->port;
+	u8 index = info->index;
+	u32 metadata;
+	int ret;
+
+	metadata = dwaddress << USB4_NVM_READ_OFFSET_SHIFT;
+	if (dwords < USB4_DATA_DWORDS)
+		metadata |= dwords << USB4_NVM_READ_LENGTH_SHIFT;
+
+	ret = usb4_port_retimer_write(port, index, USB4_SB_METADATA, &metadata,
+				      sizeof(metadata));
+	if (ret)
+		return ret;
+
+	ret = usb4_port_retimer_op(port, index, USB4_SB_OPCODE_NVM_READ, 500);
+	if (ret)
+		return ret;
+
+	return usb4_port_retimer_read(port, index, USB4_SB_DATA, buf,
+				      dwords * 4);
+}
+
+/**
+ * usb4_port_retimer_nvm_read() - Read contents of retimer NVM
+ * @port: USB4 port
+ * @index: Retimer index
+ * @address: NVM address (in bytes) to start reading
+ * @buf: Data read from NVM is stored here
+ * @size: Number of bytes to read
+ *
+ * Reads retimer NVM and copies the contents to @buf. Returns %0 if the
+ * read was successful and negative errno in case of failure.
+ * Specifically returns %-ENODEV if there is no retimer at @index.
+ */
+int usb4_port_retimer_nvm_read(struct tb_port *port, u8 index,
+			       unsigned int address, void *buf, size_t size)
+{
+	struct retimer_info info = { .port = port, .index = index };
+
+	return tb_nvm_read_data(address, buf, size, USB4_DATA_RETRIES,
+				usb4_port_retimer_nvm_read_block, &info);
+}
+
+static inline unsigned int
+usb4_usb3_port_max_bandwidth(const struct tb_port *port, unsigned int bw)
+{
+	/* Take the possible bandwidth limitation into account */
+	if (port->max_bw)
+		return min(bw, port->max_bw);
+	return bw;
+}
+
+/**
+ * usb4_usb3_port_max_link_rate() - Maximum support USB3 link rate
+ * @port: USB3 adapter port
+ *
+ * Return maximum supported link rate of a USB3 adapter in Mb/s.
+ * Negative errno in case of error.
+ */
+int usb4_usb3_port_max_link_rate(struct tb_port *port)
+{
+	int ret, lr;
+	u32 val;
+
+	if (!tb_port_is_usb3_down(port) && !tb_port_is_usb3_up(port))
+		return -EINVAL;
+
+	ret = tb_port_read(port, &val, TB_CFG_PORT,
+			   port->cap_adap + ADP_USB3_CS_4, 1);
+	if (ret)
+		return ret;
+
+	lr = (val & ADP_USB3_CS_4_MSLR_MASK) >> ADP_USB3_CS_4_MSLR_SHIFT;
+	ret = lr == ADP_USB3_CS_4_MSLR_20G ? 20000 : 10000;
+
+	return usb4_usb3_port_max_bandwidth(port, ret);
+}
+
+/**
+ * usb4_usb3_port_actual_link_rate() - Established USB3 link rate
+ * @port: USB3 adapter port
+ *
+ * Return actual established link rate of a USB3 adapter in Mb/s. If the
+ * link is not up returns %0 and negative errno in case of failure.
+ */
+int usb4_usb3_port_actual_link_rate(struct tb_port *port)
+{
+	int ret, lr;
+	u32 val;
+
+	if (!tb_port_is_usb3_down(port) && !tb_port_is_usb3_up(port))
+		return -EINVAL;
+
+	ret = tb_port_read(port, &val, TB_CFG_PORT,
+			   port->cap_adap + ADP_USB3_CS_4, 1);
+	if (ret)
+		return ret;
+
+	if (!(val & ADP_USB3_CS_4_ULV))
+		return 0;
+
+	lr = val & ADP_USB3_CS_4_ALR_MASK;
+	ret = lr == ADP_USB3_CS_4_ALR_20G ? 20000 : 10000;
+
+	return usb4_usb3_port_max_bandwidth(port, ret);
+}
+
+static int usb4_usb3_port_cm_request(struct tb_port *port, bool request)
+{
+	int ret;
+	u32 val;
+
+	if (!tb_port_is_usb3_down(port))
+		return -EINVAL;
+	if (tb_route(port->sw))
+		return -EINVAL;
+
+	ret = tb_port_read(port, &val, TB_CFG_PORT,
+			   port->cap_adap + ADP_USB3_CS_2, 1);
+	if (ret)
+		return ret;
+
+	if (request)
+		val |= ADP_USB3_CS_2_CMR;
+	else
+		val &= ~ADP_USB3_CS_2_CMR;
+
+	ret = tb_port_write(port, &val, TB_CFG_PORT,
+			    port->cap_adap + ADP_USB3_CS_2, 1);
+	if (ret)
+		return ret;
+
+	/*
+	 * We can use val here directly as the CMR bit is in the same place
+	 * as HCA. Just mask out others.
+	 */
+	val &= ADP_USB3_CS_2_CMR;
+	return usb4_port_wait_for_bit(port, port->cap_adap + ADP_USB3_CS_1,
+				      ADP_USB3_CS_1_HCA, val, 1500);
+}
+
+static inline int usb4_usb3_port_set_cm_request(struct tb_port *port)
+{
+	return usb4_usb3_port_cm_request(port, true);
+}
+
+static inline int usb4_usb3_port_clear_cm_request(struct tb_port *port)
+{
+	return usb4_usb3_port_cm_request(port, false);
+}
+
+static unsigned int usb3_bw_to_mbps(u32 bw, u8 scale)
+{
+	unsigned long uframes;
+
+	uframes = bw * 512UL << scale;
+	return DIV_ROUND_CLOSEST(uframes * 8000, MEGA);
+}
+
+static u32 mbps_to_usb3_bw(unsigned int mbps, u8 scale)
+{
+	unsigned long uframes;
+
+	/* 1 uframe is 1/8 ms (125 us) -> 1 / 8000 s */
+	uframes = ((unsigned long)mbps * MEGA) / 8000;
+	return DIV_ROUND_UP(uframes, 512UL << scale);
+}
+
+static int usb4_usb3_port_read_allocated_bandwidth(struct tb_port *port,
+						   int *upstream_bw,
+						   int *downstream_bw)
+{
+	u32 val, bw, scale;
+	int ret;
+
+	ret = tb_port_read(port, &val, TB_CFG_PORT,
+			   port->cap_adap + ADP_USB3_CS_2, 1);
+	if (ret)
+		return ret;
+
+	ret = tb_port_read(port, &scale, TB_CFG_PORT,
+			   port->cap_adap + ADP_USB3_CS_3, 1);
+	if (ret)
+		return ret;
+
+	scale &= ADP_USB3_CS_3_SCALE_MASK;
+
+	bw = val & ADP_USB3_CS_2_AUBW_MASK;
+	*upstream_bw = usb3_bw_to_mbps(bw, scale);
+
+	bw = (val & ADP_USB3_CS_2_ADBW_MASK) >> ADP_USB3_CS_2_ADBW_SHIFT;
+	*downstream_bw = usb3_bw_to_mbps(bw, scale);
+
+	return 0;
+}
+
+/**
+ * usb4_usb3_port_allocated_bandwidth() - Bandwidth allocated for USB3
+ * @port: USB3 adapter port
+ * @upstream_bw: Allocated upstream bandwidth is stored here
+ * @downstream_bw: Allocated downstream bandwidth is stored here
+ *
+ * Stores currently allocated USB3 bandwidth into @upstream_bw and
+ * @downstream_bw in Mb/s. Returns %0 in case of success and negative
+ * errno in failure.
+ */
+int usb4_usb3_port_allocated_bandwidth(struct tb_port *port, int *upstream_bw,
+				       int *downstream_bw)
+{
+	int ret;
+
+	ret = usb4_usb3_port_set_cm_request(port);
+	if (ret)
+		return ret;
+
+	ret = usb4_usb3_port_read_allocated_bandwidth(port, upstream_bw,
+						      downstream_bw);
+	usb4_usb3_port_clear_cm_request(port);
+
+	return ret;
+}
+
+static int usb4_usb3_port_read_consumed_bandwidth(struct tb_port *port,
+						  int *upstream_bw,
+						  int *downstream_bw)
+{
+	u32 val, bw, scale;
+	int ret;
+
+	ret = tb_port_read(port, &val, TB_CFG_PORT,
+			   port->cap_adap + ADP_USB3_CS_1, 1);
+	if (ret)
+		return ret;
+
+	ret = tb_port_read(port, &scale, TB_CFG_PORT,
+			   port->cap_adap + ADP_USB3_CS_3, 1);
+	if (ret)
+		return ret;
+
+	scale &= ADP_USB3_CS_3_SCALE_MASK;
+
+	bw = val & ADP_USB3_CS_1_CUBW_MASK;
+	*upstream_bw = usb3_bw_to_mbps(bw, scale);
+
+	bw = (val & ADP_USB3_CS_1_CDBW_MASK) >> ADP_USB3_CS_1_CDBW_SHIFT;
+	*downstream_bw = usb3_bw_to_mbps(bw, scale);
+
+	return 0;
+}
+
+static int usb4_usb3_port_write_allocated_bandwidth(struct tb_port *port,
+						    int upstream_bw,
+						    int downstream_bw)
+{
+	u32 val, ubw, dbw, scale;
+	int ret, max_bw;
+
+	/* Figure out suitable scale */
+	scale = 0;
+	max_bw = max(upstream_bw, downstream_bw);
+	while (scale < 64) {
+		if (mbps_to_usb3_bw(max_bw, scale) < 4096)
+			break;
+		scale++;
+	}
+
+	if (WARN_ON(scale >= 64))
+		return -EINVAL;
+
+	ret = tb_port_write(port, &scale, TB_CFG_PORT,
+			    port->cap_adap + ADP_USB3_CS_3, 1);
+	if (ret)
+		return ret;
+
+	ubw = mbps_to_usb3_bw(upstream_bw, scale);
+	dbw = mbps_to_usb3_bw(downstream_bw, scale);
+
+	tb_port_dbg(port, "scaled bandwidth %u/%u, scale %u\n", ubw, dbw, scale);
+
+	ret = tb_port_read(port, &val, TB_CFG_PORT,
+			   port->cap_adap + ADP_USB3_CS_2, 1);
+	if (ret)
+		return ret;
+
+	val &= ~(ADP_USB3_CS_2_AUBW_MASK | ADP_USB3_CS_2_ADBW_MASK);
+	val |= dbw << ADP_USB3_CS_2_ADBW_SHIFT;
+	val |= ubw;
+
+	return tb_port_write(port, &val, TB_CFG_PORT,
+			     port->cap_adap + ADP_USB3_CS_2, 1);
+}
+
+/**
+ * usb4_usb3_port_allocate_bandwidth() - Allocate bandwidth for USB3
+ * @port: USB3 adapter port
+ * @upstream_bw: New upstream bandwidth
+ * @downstream_bw: New downstream bandwidth
+ *
+ * This can be used to set how much bandwidth is allocated for the USB3
+ * tunneled isochronous traffic. @upstream_bw and @downstream_bw are the
+ * new values programmed to the USB3 adapter allocation registers. If
+ * the values are lower than what is currently consumed the allocation
+ * is set to what is currently consumed instead (consumed bandwidth
+ * cannot be taken away by CM). The actual new values are returned in
+ * @upstream_bw and @downstream_bw.
+ *
+ * Returns %0 in case of success and negative errno if there was a
+ * failure.
+ */
+int usb4_usb3_port_allocate_bandwidth(struct tb_port *port, int *upstream_bw,
+				      int *downstream_bw)
+{
+	int ret, consumed_up, consumed_down, allocate_up, allocate_down;
+
+	ret = usb4_usb3_port_set_cm_request(port);
+	if (ret)
+		return ret;
+
+	ret = usb4_usb3_port_read_consumed_bandwidth(port, &consumed_up,
+						     &consumed_down);
+	if (ret)
+		goto err_request;
+
+	/* Don't allow it go lower than what is consumed */
+	allocate_up = max(*upstream_bw, consumed_up);
+	allocate_down = max(*downstream_bw, consumed_down);
+
+	ret = usb4_usb3_port_write_allocated_bandwidth(port, allocate_up,
+						       allocate_down);
+	if (ret)
+		goto err_request;
+
+	*upstream_bw = allocate_up;
+	*downstream_bw = allocate_down;
+
+err_request:
+	usb4_usb3_port_clear_cm_request(port);
+	return ret;
+}
+
+/**
+ * usb4_usb3_port_release_bandwidth() - Release allocated USB3 bandwidth
+ * @port: USB3 adapter port
+ * @upstream_bw: New allocated upstream bandwidth
+ * @downstream_bw: New allocated downstream bandwidth
+ *
+ * Releases USB3 allocated bandwidth down to what is actually consumed.
+ * The new bandwidth is returned in @upstream_bw and @downstream_bw.
+ *
+ * Returns 0% in success and negative errno in case of failure.
+ */
+int usb4_usb3_port_release_bandwidth(struct tb_port *port, int *upstream_bw,
+				     int *downstream_bw)
+{
+	int ret, consumed_up, consumed_down;
+
+	ret = usb4_usb3_port_set_cm_request(port);
+	if (ret)
+		return ret;
+
+	ret = usb4_usb3_port_read_consumed_bandwidth(port, &consumed_up,
+						     &consumed_down);
+	if (ret)
+		goto err_request;
+
+	/*
+	 * Always keep 1000 Mb/s to make sure xHCI has at least some
+	 * bandwidth available for isochronous traffic.
+	 */
+	if (consumed_up < 1000)
+		consumed_up = 1000;
+	if (consumed_down < 1000)
+		consumed_down = 1000;
+
+	ret = usb4_usb3_port_write_allocated_bandwidth(port, consumed_up,
+						       consumed_down);
+	if (ret)
+		goto err_request;
+
+	*upstream_bw = consumed_up;
+	*downstream_bw = consumed_down;
+
+err_request:
+	usb4_usb3_port_clear_cm_request(port);
+	return ret;
+}
+
+static bool is_usb4_dpin(const struct tb_port *port)
+{
+	if (!tb_port_is_dpin(port))
+		return false;
+	if (!tb_switch_is_usb4(port->sw))
+		return false;
+	return true;
+}
+
+/**
+ * usb4_dp_port_set_cm_id() - Assign CM ID to the DP IN adapter
+ * @port: DP IN adapter
+ * @cm_id: CM ID to assign
+ *
+ * Sets CM ID for the @port. Returns %0 on success and negative errno
+ * otherwise. Speficially returns %-EOPNOTSUPP if the @port does not
+ * support this.
+ */
+int usb4_dp_port_set_cm_id(struct tb_port *port, int cm_id)
+{
+	u32 val;
+	int ret;
+
+	if (!is_usb4_dpin(port))
+		return -EOPNOTSUPP;
+
+	ret = tb_port_read(port, &val, TB_CFG_PORT,
+			   port->cap_adap + ADP_DP_CS_2, 1);
+	if (ret)
+		return ret;
+
+	val &= ~ADP_DP_CS_2_CM_ID_MASK;
+	val |= cm_id << ADP_DP_CS_2_CM_ID_SHIFT;
+
+	return tb_port_write(port, &val, TB_CFG_PORT,
+			     port->cap_adap + ADP_DP_CS_2, 1);
+}
+
+/**
+ * usb4_dp_port_bandwidth_mode_supported() - Is the bandwidth allocation mode
+ *					     supported
+ * @port: DP IN adapter to check
+ *
+ * Can be called to any DP IN adapter. Returns true if the adapter
+ * supports USB4 bandwidth allocation mode, false otherwise.
+ */
+bool usb4_dp_port_bandwidth_mode_supported(struct tb_port *port)
+{
+	int ret;
+	u32 val;
+
+	if (!is_usb4_dpin(port))
+		return false;
+
+	ret = tb_port_read(port, &val, TB_CFG_PORT,
+			   port->cap_adap + DP_LOCAL_CAP, 1);
+	if (ret)
+		return false;
+
+	return !!(val & DP_COMMON_CAP_BW_MODE);
+}
+
+/**
+ * usb4_dp_port_bandwidth_mode_enabled() - Is the bandwidth allocation mode
+ *					   enabled
+ * @port: DP IN adapter to check
+ *
+ * Can be called to any DP IN adapter. Returns true if the bandwidth
+ * allocation mode has been enabled, false otherwise.
+ */
+bool usb4_dp_port_bandwidth_mode_enabled(struct tb_port *port)
+{
+	int ret;
+	u32 val;
+
+	if (!is_usb4_dpin(port))
+		return false;
+
+	ret = tb_port_read(port, &val, TB_CFG_PORT,
+			   port->cap_adap + ADP_DP_CS_8, 1);
+	if (ret)
+		return false;
+
+	return !!(val & ADP_DP_CS_8_DPME);
+}
+
+/**
+ * usb4_dp_port_set_cm_bandwidth_mode_supported() - Set/clear CM support for
+ *						    bandwidth allocation mode
+ * @port: DP IN adapter
+ * @supported: Does the CM support bandwidth allocation mode
+ *
+ * Can be called to any DP IN adapter. Sets or clears the CM support bit
+ * of the DP IN adapter. Returns %0 in success and negative errno
+ * otherwise. Specifically returns %-OPNOTSUPP if the passed in adapter
+ * does not support this.
+ */
+int usb4_dp_port_set_cm_bandwidth_mode_supported(struct tb_port *port,
+						 bool supported)
+{
+	u32 val;
+	int ret;
+
+	if (!is_usb4_dpin(port))
+		return -EOPNOTSUPP;
+
+	ret = tb_port_read(port, &val, TB_CFG_PORT,
+			   port->cap_adap + ADP_DP_CS_2, 1);
+	if (ret)
+		return ret;
+
+	if (supported)
+		val |= ADP_DP_CS_2_CMMS;
+	else
+		val &= ~ADP_DP_CS_2_CMMS;
+
+	return tb_port_write(port, &val, TB_CFG_PORT,
+			     port->cap_adap + ADP_DP_CS_2, 1);
+}
+
+/**
+ * usb4_dp_port_group_id() - Return Group ID assigned for the adapter
+ * @port: DP IN adapter
+ *
+ * Reads bandwidth allocation Group ID from the DP IN adapter and
+ * returns it. If the adapter does not support setting Group_ID
+ * %-EOPNOTSUPP is returned.
+ */
+int usb4_dp_port_group_id(struct tb_port *port)
+{
+	u32 val;
+	int ret;
+
+	if (!is_usb4_dpin(port))
+		return -EOPNOTSUPP;
+
+	ret = tb_port_read(port, &val, TB_CFG_PORT,
+			   port->cap_adap + ADP_DP_CS_2, 1);
+	if (ret)
+		return ret;
+
+	return (val & ADP_DP_CS_2_GROUP_ID_MASK) >> ADP_DP_CS_2_GROUP_ID_SHIFT;
+}
+
+/**
+ * usb4_dp_port_set_group_id() - Set adapter Group ID
+ * @port: DP IN adapter
+ * @group_id: Group ID for the adapter
+ *
+ * Sets bandwidth allocation mode Group ID for the DP IN adapter.
+ * Returns %0 in case of success and negative errno otherwise.
+ * Specifically returns %-EOPNOTSUPP if the adapter does not support
+ * this.
+ */
+int usb4_dp_port_set_group_id(struct tb_port *port, int group_id)
+{
+	u32 val;
+	int ret;
+
+	if (!is_usb4_dpin(port))
+		return -EOPNOTSUPP;
+
+	ret = tb_port_read(port, &val, TB_CFG_PORT,
+			   port->cap_adap + ADP_DP_CS_2, 1);
+	if (ret)
+		return ret;
+
+	val &= ~ADP_DP_CS_2_GROUP_ID_MASK;
+	val |= group_id << ADP_DP_CS_2_GROUP_ID_SHIFT;
+
+	return tb_port_write(port, &val, TB_CFG_PORT,
+			     port->cap_adap + ADP_DP_CS_2, 1);
+}
+
+/**
+ * usb4_dp_port_nrd() - Read non-reduced rate and lanes
+ * @port: DP IN adapter
+ * @rate: Non-reduced rate in Mb/s is placed here
+ * @lanes: Non-reduced lanes are placed here
+ *
+ * Reads the non-reduced rate and lanes from the DP IN adapter. Returns
+ * %0 in success and negative errno otherwise. Specifically returns
+ * %-EOPNOTSUPP if the adapter does not support this.
+ */
+int usb4_dp_port_nrd(struct tb_port *port, int *rate, int *lanes)
+{
+	u32 val, tmp;
+	int ret;
+
+	if (!is_usb4_dpin(port))
+		return -EOPNOTSUPP;
+
+	ret = tb_port_read(port, &val, TB_CFG_PORT,
+			   port->cap_adap + ADP_DP_CS_2, 1);
+	if (ret)
+		return ret;
+
+	tmp = (val & ADP_DP_CS_2_NRD_MLR_MASK) >> ADP_DP_CS_2_NRD_MLR_SHIFT;
+	switch (tmp) {
+	case DP_COMMON_CAP_RATE_RBR:
+		*rate = 1620;
+		break;
+	case DP_COMMON_CAP_RATE_HBR:
+		*rate = 2700;
+		break;
+	case DP_COMMON_CAP_RATE_HBR2:
+		*rate = 5400;
+		break;
+	case DP_COMMON_CAP_RATE_HBR3:
+		*rate = 8100;
+		break;
+	}
+
+	tmp = val & ADP_DP_CS_2_NRD_MLC_MASK;
+	switch (tmp) {
+	case DP_COMMON_CAP_1_LANE:
+		*lanes = 1;
+		break;
+	case DP_COMMON_CAP_2_LANES:
+		*lanes = 2;
+		break;
+	case DP_COMMON_CAP_4_LANES:
+		*lanes = 4;
+		break;
+	}
+
+	return 0;
+}
+
+/**
+ * usb4_dp_port_set_nrd() - Set non-reduced rate and lanes
+ * @port: DP IN adapter
+ * @rate: Non-reduced rate in Mb/s
+ * @lanes: Non-reduced lanes
+ *
+ * Before the capabilities reduction this function can be used to set
+ * the non-reduced values for the DP IN adapter. Returns %0 in success
+ * and negative errno otherwise. If the adapter does not support this
+ * %-EOPNOTSUPP is returned.
+ */
+int usb4_dp_port_set_nrd(struct tb_port *port, int rate, int lanes)
+{
+	u32 val;
+	int ret;
+
+	if (!is_usb4_dpin(port))
+		return -EOPNOTSUPP;
+
+	ret = tb_port_read(port, &val, TB_CFG_PORT,
+			   port->cap_adap + ADP_DP_CS_2, 1);
+	if (ret)
+		return ret;
+
+	val &= ~ADP_DP_CS_2_NRD_MLR_MASK;
+
+	switch (rate) {
+	case 1620:
+		break;
+	case 2700:
+		val |= (DP_COMMON_CAP_RATE_HBR << ADP_DP_CS_2_NRD_MLR_SHIFT)
+			& ADP_DP_CS_2_NRD_MLR_MASK;
+		break;
+	case 5400:
+		val |= (DP_COMMON_CAP_RATE_HBR2 << ADP_DP_CS_2_NRD_MLR_SHIFT)
+			& ADP_DP_CS_2_NRD_MLR_MASK;
+		break;
+	case 8100:
+		val |= (DP_COMMON_CAP_RATE_HBR3 << ADP_DP_CS_2_NRD_MLR_SHIFT)
+			& ADP_DP_CS_2_NRD_MLR_MASK;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	val &= ~ADP_DP_CS_2_NRD_MLC_MASK;
+
+	switch (lanes) {
+	case 1:
+		break;
+	case 2:
+		val |= DP_COMMON_CAP_2_LANES;
+		break;
+	case 4:
+		val |= DP_COMMON_CAP_4_LANES;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return tb_port_write(port, &val, TB_CFG_PORT,
+			     port->cap_adap + ADP_DP_CS_2, 1);
+}
+
+/**
+ * usb4_dp_port_granularity() - Return granularity for the bandwidth values
+ * @port: DP IN adapter
+ *
+ * Reads the programmed granularity from @port. If the DP IN adapter does
+ * not support bandwidth allocation mode returns %-EOPNOTSUPP and negative
+ * errno in other error cases.
+ */
+int usb4_dp_port_granularity(struct tb_port *port)
+{
+	u32 val;
+	int ret;
+
+	if (!is_usb4_dpin(port))
+		return -EOPNOTSUPP;
+
+	ret = tb_port_read(port, &val, TB_CFG_PORT,
+			   port->cap_adap + ADP_DP_CS_2, 1);
+	if (ret)
+		return ret;
+
+	val &= ADP_DP_CS_2_GR_MASK;
+	val >>= ADP_DP_CS_2_GR_SHIFT;
+
+	switch (val) {
+	case ADP_DP_CS_2_GR_0_25G:
+		return 250;
+	case ADP_DP_CS_2_GR_0_5G:
+		return 500;
+	case ADP_DP_CS_2_GR_1G:
+		return 1000;
+	}
+
+	return -EINVAL;
+}
+
+/**
+ * usb4_dp_port_set_granularity() - Set granularity for the bandwidth values
+ * @port: DP IN adapter
+ * @granularity: Granularity in Mb/s. Supported values: 1000, 500 and 250.
+ *
+ * Sets the granularity used with the estimated, allocated and requested
+ * bandwidth. Returns %0 in success and negative errno otherwise. If the
+ * adapter does not support this %-EOPNOTSUPP is returned.
+ */
+int usb4_dp_port_set_granularity(struct tb_port *port, int granularity)
+{
+	u32 val;
+	int ret;
+
+	if (!is_usb4_dpin(port))
+		return -EOPNOTSUPP;
+
+	ret = tb_port_read(port, &val, TB_CFG_PORT,
+			   port->cap_adap + ADP_DP_CS_2, 1);
+	if (ret)
+		return ret;
+
+	val &= ~ADP_DP_CS_2_GR_MASK;
+
+	switch (granularity) {
+	case 250:
+		val |= ADP_DP_CS_2_GR_0_25G << ADP_DP_CS_2_GR_SHIFT;
+		break;
+	case 500:
+		val |= ADP_DP_CS_2_GR_0_5G << ADP_DP_CS_2_GR_SHIFT;
+		break;
+	case 1000:
+		val |= ADP_DP_CS_2_GR_1G << ADP_DP_CS_2_GR_SHIFT;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return tb_port_write(port, &val, TB_CFG_PORT,
+			     port->cap_adap + ADP_DP_CS_2, 1);
+}
+
+/**
+ * usb4_dp_port_set_estimated_bandwidth() - Set estimated bandwidth
+ * @port: DP IN adapter
+ * @bw: Estimated bandwidth in Mb/s.
+ *
+ * Sets the estimated bandwidth to @bw. Set the granularity by calling
+ * usb4_dp_port_set_granularity() before calling this. The @bw is round
+ * down to the closest granularity multiplier. Returns %0 in success
+ * and negative errno otherwise. Specifically returns %-EOPNOTSUPP if
+ * the adapter does not support this.
+ */
+int usb4_dp_port_set_estimated_bandwidth(struct tb_port *port, int bw)
+{
+	u32 val, granularity;
+	int ret;
+
+	if (!is_usb4_dpin(port))
+		return -EOPNOTSUPP;
+
+	ret = usb4_dp_port_granularity(port);
+	if (ret < 0)
+		return ret;
+	granularity = ret;
+
+	ret = tb_port_read(port, &val, TB_CFG_PORT,
+			   port->cap_adap + ADP_DP_CS_2, 1);
+	if (ret)
+		return ret;
+
+	val &= ~ADP_DP_CS_2_ESTIMATED_BW_MASK;
+	val |= (bw / granularity) << ADP_DP_CS_2_ESTIMATED_BW_SHIFT;
+
+	return tb_port_write(port, &val, TB_CFG_PORT,
+			     port->cap_adap + ADP_DP_CS_2, 1);
+}
+
+/**
+ * usb4_dp_port_allocated_bandwidth() - Return allocated bandwidth
+ * @port: DP IN adapter
+ *
+ * Reads and returns allocated bandwidth for @port in Mb/s (taking into
+ * account the programmed granularity). Returns negative errno in case
+ * of error.
+ */
+int usb4_dp_port_allocated_bandwidth(struct tb_port *port)
+{
+	u32 val, granularity;
+	int ret;
+
+	if (!is_usb4_dpin(port))
+		return -EOPNOTSUPP;
+
+	ret = usb4_dp_port_granularity(port);
+	if (ret < 0)
+		return ret;
+	granularity = ret;
+
+	ret = tb_port_read(port, &val, TB_CFG_PORT,
+			   port->cap_adap + DP_STATUS, 1);
+	if (ret)
+		return ret;
+
+	val &= DP_STATUS_ALLOCATED_BW_MASK;
+	val >>= DP_STATUS_ALLOCATED_BW_SHIFT;
+
+	return val * granularity;
+}
+
+static int __usb4_dp_port_set_cm_ack(struct tb_port *port, bool ack)
+{
+	u32 val;
+	int ret;
+
+	ret = tb_port_read(port, &val, TB_CFG_PORT,
+			   port->cap_adap + ADP_DP_CS_2, 1);
+	if (ret)
+		return ret;
+
+	if (ack)
+		val |= ADP_DP_CS_2_CA;
+	else
+		val &= ~ADP_DP_CS_2_CA;
+
+	return tb_port_write(port, &val, TB_CFG_PORT,
+			     port->cap_adap + ADP_DP_CS_2, 1);
+}
+
+static inline int usb4_dp_port_set_cm_ack(struct tb_port *port)
+{
+	return __usb4_dp_port_set_cm_ack(port, true);
+}
+
+static int usb4_dp_port_wait_and_clear_cm_ack(struct tb_port *port,
+					      int timeout_msec)
+{
+	ktime_t end;
+	u32 val;
+	int ret;
+
+	ret = __usb4_dp_port_set_cm_ack(port, false);
+	if (ret)
+		return ret;
+
+	end = ktime_add_ms(ktime_get(), timeout_msec);
+	do {
+		ret = tb_port_read(port, &val, TB_CFG_PORT,
+				   port->cap_adap + ADP_DP_CS_8, 1);
+		if (ret)
+			return ret;
+
+		if (!(val & ADP_DP_CS_8_DR))
+			break;
+
+		usleep_range(50, 100);
+	} while (ktime_before(ktime_get(), end));
+
+	if (val & ADP_DP_CS_8_DR)
+		return -ETIMEDOUT;
+
+	ret = tb_port_read(port, &val, TB_CFG_PORT,
+			   port->cap_adap + ADP_DP_CS_2, 1);
+	if (ret)
+		return ret;
+
+	val &= ~ADP_DP_CS_2_CA;
+	return tb_port_write(port, &val, TB_CFG_PORT,
+			     port->cap_adap + ADP_DP_CS_2, 1);
+}
+
+/**
+ * usb4_dp_port_allocate_bandwidth() - Set allocated bandwidth
+ * @port: DP IN adapter
+ * @bw: New allocated bandwidth in Mb/s
+ *
+ * Communicates the new allocated bandwidth with the DPCD (graphics
+ * driver). Takes into account the programmed granularity. Returns %0 in
+ * success and negative errno in case of error.
+ */
+int usb4_dp_port_allocate_bandwidth(struct tb_port *port, int bw)
+{
+	u32 val, granularity;
+	int ret;
+
+	if (!is_usb4_dpin(port))
+		return -EOPNOTSUPP;
+
+	ret = usb4_dp_port_granularity(port);
+	if (ret < 0)
+		return ret;
+	granularity = ret;
+
+	ret = tb_port_read(port, &val, TB_CFG_PORT,
+			   port->cap_adap + DP_STATUS, 1);
+	if (ret)
+		return ret;
+
+	val &= ~DP_STATUS_ALLOCATED_BW_MASK;
+	val |= (bw / granularity) << DP_STATUS_ALLOCATED_BW_SHIFT;
+
+	ret = tb_port_write(port, &val, TB_CFG_PORT,
+			    port->cap_adap + DP_STATUS, 1);
+	if (ret)
+		return ret;
+
+	ret = usb4_dp_port_set_cm_ack(port);
+	if (ret)
+		return ret;
+
+	return usb4_dp_port_wait_and_clear_cm_ack(port, 500);
+}
+
+/**
+ * usb4_dp_port_requested_bandwidth() - Read requested bandwidth
+ * @port: DP IN adapter
+ *
+ * Reads the DPCD (graphics driver) requested bandwidth and returns it
+ * in Mb/s. Takes the programmed granularity into account. In case of
+ * error returns negative errno. Specifically returns %-EOPNOTSUPP if
+ * the adapter does not support bandwidth allocation mode, and %ENODATA
+ * if there is no active bandwidth request from the graphics driver.
+ */
+int usb4_dp_port_requested_bandwidth(struct tb_port *port)
+{
+	u32 val, granularity;
+	int ret;
+
+	if (!is_usb4_dpin(port))
+		return -EOPNOTSUPP;
+
+	ret = usb4_dp_port_granularity(port);
+	if (ret < 0)
+		return ret;
+	granularity = ret;
+
+	ret = tb_port_read(port, &val, TB_CFG_PORT,
+			   port->cap_adap + ADP_DP_CS_8, 1);
+	if (ret)
+		return ret;
+
+	if (!(val & ADP_DP_CS_8_DR))
+		return -ENODATA;
+
+	return (val & ADP_DP_CS_8_REQUESTED_BW_MASK) * granularity;
+}
+
+/**
+ * usb4_pci_port_set_ext_encapsulation() - Enable/disable extended encapsulation
+ * @port: PCIe adapter
+ * @enable: Enable/disable extended encapsulation
+ *
+ * Enables or disables extended encapsulation used in PCIe tunneling. Caller
+ * needs to make sure both adapters support this before enabling. Returns %0 on
+ * success and negative errno otherwise.
+ */
+int usb4_pci_port_set_ext_encapsulation(struct tb_port *port, bool enable)
+{
+	u32 val;
+	int ret;
+
+	if (!tb_port_is_pcie_up(port) && !tb_port_is_pcie_down(port))
+		return -EINVAL;
+
+	ret = tb_port_read(port, &val, TB_CFG_PORT,
+			   port->cap_adap + ADP_PCIE_CS_1, 1);
+	if (ret)
+		return ret;
+
+	if (enable)
+		val |= ADP_PCIE_CS_1_EE;
+	else
+		val &= ~ADP_PCIE_CS_1_EE;
+
+	return tb_port_write(port, &val, TB_CFG_PORT,
+			     port->cap_adap + ADP_PCIE_CS_1, 1);
+}