Merge tag 'thunderbolt-for-v5.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/westeri/thunderbolt into usb-next

Mika writes:

thunderbolt: Changes for v5.10 merge window

This includes following Thunderbolt/USB4 changes for v5.10 merge window:

  * A couple of optimizations around Tiger Lake force power logic and
    NHI (Native Host Interface) LC (Link Controller) mailbox command
    processing

  * Power management improvements for Software Connection Manager

  * Debugfs support

  * Allow KUnit tests to be enabled also when Thunderbolt driver is
    configured as module.

  * Few minor cleanups and fixes

All these have been in linux-next with no reported issues.

* tag 'thunderbolt-for-v5.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/westeri/thunderbolt: (37 commits)
  thunderbolt: Capitalize comment on top of QUIRK_FORCE_POWER_LINK_CONTROLLER
  thunderbolt: Correct tb_check_quirks() kernel-doc
  thunderbolt: Log correct zeroX entries in decode_error()
  thunderbolt: Handle ERR_LOCK notification
  thunderbolt: Use "if USB4" instead of "depends on" in Kconfig
  thunderbolt: Allow KUnit tests to be built also when CONFIG_USB4=m
  thunderbolt: Only stop control channel when entering freeze
  thunderbolt: debugfs: Fix uninitialized return in counters_write()
  thunderbolt: Add debugfs interface
  thunderbolt: No need to warn in TB_CFG_ERROR_INVALID_CONFIG_SPACE
  thunderbolt: Introduce tb_switch_is_tiger_lake()
  thunderbolt: Introduce tb_switch_is_ice_lake()
  thunderbolt: Check for Intel vendor ID when identifying controller
  thunderbolt: Introduce tb_port_is_nhi()
  thunderbolt: Introduce tb_switch_next_cap()
  thunderbolt: Introduce tb_port_next_cap()
  thunderbolt: Move struct tb_cap_any to tb_regs.h
  thunderbolt: Add runtime PM for Software CM
  thunderbolt: Create device links from ACPI description
  ACPI: Export acpi_get_first_physical_node() to modules
  ...

21 files changed, 1971 insertions, 291 deletions

diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c
index 54002670cb7a..53cc1e0cef21 100644
--- a/drivers/acpi/bus.c
+++ b/drivers/acpi/bus.c
@@ -551,6 +551,7 @@ struct device *acpi_get_first_physical_node(struct acpi_device *adev)
 	mutex_unlock(physical_node_lock);
 	return phys_dev;
 }
+EXPORT_SYMBOL_GPL(acpi_get_first_physical_node);
 
 static struct acpi_device *acpi_primary_dev_companion(struct acpi_device *adev,
 						      const struct device *dev)
diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index 2a589b6d6ed8..01f23e30bd8f 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -3673,63 +3673,6 @@ static void quirk_apple_poweroff_thunderbolt(struct pci_dev *dev)
 DECLARE_PCI_FIXUP_SUSPEND_LATE(PCI_VENDOR_ID_INTEL,
 			       PCI_DEVICE_ID_INTEL_CACTUS_RIDGE_4C,
 			       quirk_apple_poweroff_thunderbolt);
-
-/*
- * Apple: Wait for the Thunderbolt controller to reestablish PCI tunnels
- *
- * During suspend the Thunderbolt controller is reset and all PCI
- * tunnels are lost. The NHI driver will try to reestablish all tunnels
- * during resume. We have to manually wait for the NHI since there is
- * no parent child relationship between the NHI and the tunneled
- * bridges.
- */
-static void quirk_apple_wait_for_thunderbolt(struct pci_dev *dev)
-{
-	struct pci_dev *sibling = NULL;
-	struct pci_dev *nhi = NULL;
-
-	if (!x86_apple_machine)
-		return;
-	if (pci_pcie_type(dev) != PCI_EXP_TYPE_DOWNSTREAM)
-		return;
-
-	/*
-	 * Find the NHI and confirm that we are a bridge on the Thunderbolt
-	 * host controller and not on a Thunderbolt endpoint.
-	 */
-	sibling = pci_get_slot(dev->bus, 0x0);
-	if (sibling == dev)
-		goto out; /* we are the downstream bridge to the NHI */
-	if (!sibling || !sibling->subordinate)
-		goto out;
-	nhi = pci_get_slot(sibling->subordinate, 0x0);
-	if (!nhi)
-		goto out;
-	if (nhi->vendor != PCI_VENDOR_ID_INTEL
-		    || (nhi->device != PCI_DEVICE_ID_INTEL_LIGHT_RIDGE &&
-			nhi->device != PCI_DEVICE_ID_INTEL_CACTUS_RIDGE_4C &&
-			nhi->device != PCI_DEVICE_ID_INTEL_FALCON_RIDGE_2C_NHI &&
-			nhi->device != PCI_DEVICE_ID_INTEL_FALCON_RIDGE_4C_NHI)
-		    || nhi->class != PCI_CLASS_SYSTEM_OTHER << 8)
-		goto out;
-	pci_info(dev, "quirk: waiting for Thunderbolt to reestablish PCI tunnels...\n");
-	device_pm_wait_for_dev(&dev->dev, &nhi->dev);
-out:
-	pci_dev_put(nhi);
-	pci_dev_put(sibling);
-}
-DECLARE_PCI_FIXUP_RESUME_EARLY(PCI_VENDOR_ID_INTEL,
-			       PCI_DEVICE_ID_INTEL_LIGHT_RIDGE,
-			       quirk_apple_wait_for_thunderbolt);
-DECLARE_PCI_FIXUP_RESUME_EARLY(PCI_VENDOR_ID_INTEL,
-			       PCI_DEVICE_ID_INTEL_CACTUS_RIDGE_4C,
-			       quirk_apple_wait_for_thunderbolt);
-DECLARE_PCI_FIXUP_RESUME_EARLY(PCI_VENDOR_ID_INTEL,
-			       PCI_DEVICE_ID_INTEL_FALCON_RIDGE_2C_BRIDGE,
-			       quirk_apple_wait_for_thunderbolt);
-DECLARE_PCI_FIXUP_RESUME_EARLY(PCI_VENDOR_ID_INTEL,
-			       PCI_DEVICE_ID_INTEL_FALCON_RIDGE_4C_BRIDGE,
-			       quirk_apple_wait_for_thunderbolt);
 #endif
 
 /*
diff --git a/drivers/thunderbolt/Kconfig b/drivers/thunderbolt/Kconfig
index 354e61c0f2e5..7fc058f81d00 100644
--- a/drivers/thunderbolt/Kconfig
+++ b/drivers/thunderbolt/Kconfig
@@ -16,7 +16,19 @@ menuconfig USB4
 	  To compile this driver a module, choose M here. The module will be
 	  called thunderbolt.
 
+if USB4
+
+config USB4_DEBUGFS_WRITE
+	bool "Enable write by debugfs to configuration spaces (DANGEROUS)"
+	help
+	  Enables writing to device configuration registers through
+	  debugfs interface.
+
+	  Only enable this if you know what you are doing! Never enable
+	  this for production systems or distro kernels.
+
 config USB4_KUNIT_TEST
 	bool "KUnit tests"
 	depends on KUNIT=y
-	depends on USB4=y
+
+endif # USB4
diff --git a/drivers/thunderbolt/Makefile b/drivers/thunderbolt/Makefile
index 4ab5bfad7bfd..571537371072 100644
--- a/drivers/thunderbolt/Makefile
+++ b/drivers/thunderbolt/Makefile
@@ -4,4 +4,6 @@ thunderbolt-objs := nhi.o nhi_ops.o ctl.o tb.o switch.o cap.o path.o tunnel.o ee
 thunderbolt-objs += domain.o dma_port.o icm.o property.o xdomain.o lc.o tmu.o usb4.o
 thunderbolt-objs += nvm.o retimer.o quirks.o
 
-obj-${CONFIG_USB4_KUNIT_TEST} += test.o
+thunderbolt-${CONFIG_ACPI} += acpi.o
+thunderbolt-$(CONFIG_DEBUG_FS) += debugfs.o
+thunderbolt-${CONFIG_USB4_KUNIT_TEST} += test.o
diff --git a/drivers/thunderbolt/acpi.c b/drivers/thunderbolt/acpi.c
new file mode 100644
index 000000000000..a5f988a9f948
--- /dev/null
+++ b/drivers/thunderbolt/acpi.c
@@ -0,0 +1,117 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * ACPI support
+ *
+ * Copyright (C) 2020, Intel Corporation
+ * Author: Mika Westerberg <mika.westerberg@linux.intel.com>
+ */
+
+#include <linux/acpi.h>
+
+#include "tb.h"
+
+static acpi_status tb_acpi_add_link(acpi_handle handle, u32 level, void *data,
+				    void **return_value)
+{
+	struct fwnode_reference_args args;
+	struct fwnode_handle *fwnode;
+	struct tb_nhi *nhi = data;
+	struct acpi_device *adev;
+	struct pci_dev *pdev;
+	struct device *dev;
+	int ret;
+
+	if (acpi_bus_get_device(handle, &adev))
+		return AE_OK;
+
+	fwnode = acpi_fwnode_handle(adev);
+	ret = fwnode_property_get_reference_args(fwnode, "usb4-host-interface",
+						 NULL, 0, 0, &args);
+	if (ret)
+		return AE_OK;
+
+	/* It needs to reference this NHI */
+	if (nhi->pdev->dev.fwnode != args.fwnode)
+		goto out_put;
+
+	/*
+	 * Try to find physical device walking upwards to the hierarcy.
+	 * We need to do this because the xHCI driver might not yet be
+	 * bound so the USB3 SuperSpeed ports are not yet created.
+	 */
+	dev = acpi_get_first_physical_node(adev);
+	while (!dev) {
+		adev = adev->parent;
+		if (!adev)
+			break;
+		dev = acpi_get_first_physical_node(adev);
+	}
+
+	if (!dev)
+		goto out_put;
+
+	/*
+	 * Check that the device is PCIe. This is because USB3
+	 * SuperSpeed ports have this property and they are not power
+	 * managed with the xHCI and the SuperSpeed hub so we create the
+	 * link from xHCI instead.
+	 */
+	while (!dev_is_pci(dev))
+		dev = dev->parent;
+
+	if (!dev)
+		goto out_put;
+
+	/*
+	 * Check that this actually matches the type of device we
+	 * expect. It should either be xHCI or PCIe root/downstream
+	 * port.
+	 */
+	pdev = to_pci_dev(dev);
+	if (pdev->class == PCI_CLASS_SERIAL_USB_XHCI ||
+	    (pci_is_pcie(pdev) &&
+		(pci_pcie_type(pdev) == PCI_EXP_TYPE_ROOT_PORT ||
+		 pci_pcie_type(pdev) == PCI_EXP_TYPE_DOWNSTREAM))) {
+		const struct device_link *link;
+
+		link = device_link_add(&pdev->dev, &nhi->pdev->dev,
+				       DL_FLAG_AUTOREMOVE_SUPPLIER |
+				       DL_FLAG_PM_RUNTIME);
+		if (link) {
+			dev_dbg(&nhi->pdev->dev, "created link from %s\n",
+				dev_name(&pdev->dev));
+		} else {
+			dev_warn(&nhi->pdev->dev, "device link creation from %s failed\n",
+				 dev_name(&pdev->dev));
+		}
+	}
+
+out_put:
+	fwnode_handle_put(args.fwnode);
+	return AE_OK;
+}
+
+/**
+ * tb_acpi_add_links() - Add device links based on ACPI description
+ * @nhi: Pointer to NHI
+ *
+ * Goes over ACPI namespace finding tunneled ports that reference to
+ * @nhi ACPI node. For each reference a device link is added. The link
+ * is automatically removed by the driver core.
+ */
+void tb_acpi_add_links(struct tb_nhi *nhi)
+{
+	acpi_status status;
+
+	if (!has_acpi_companion(&nhi->pdev->dev))
+		return;
+
+	/*
+	 * Find all devices that have usb4-host-controller interface
+	 * property that references to this NHI.
+	 */
+	status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT, 32,
+				     tb_acpi_add_link, NULL, nhi, NULL);
+	if (ACPI_FAILURE(status))
+		dev_warn(&nhi->pdev->dev, "failed to enumerate tunneled ports\n");
+}
diff --git a/drivers/thunderbolt/cap.c b/drivers/thunderbolt/cap.c
index 19db6cdc5b70..6f571e912cf2 100644
--- a/drivers/thunderbolt/cap.c
+++ b/drivers/thunderbolt/cap.c
@@ -15,14 +15,6 @@
 #define VSE_CAP_OFFSET_MAX	0xffff
 #define TMU_ACCESS_EN		BIT(20)
 
-struct tb_cap_any {
-	union {
-		struct tb_cap_basic basic;
-		struct tb_cap_extended_short extended_short;
-		struct tb_cap_extended_long extended_long;
-	};
-} __packed;
-
 static int tb_port_enable_tmu(struct tb_port *port, bool enable)
 {
 	struct tb_switch *sw = port->sw;
@@ -67,23 +59,50 @@ static void tb_port_dummy_read(struct tb_port *port)
 	}
 }
 
+/**
+ * tb_port_next_cap() - Return next capability in the linked list
+ * @port: Port to find the capability for
+ * @offset: Previous capability offset (%0 for start)
+ *
+ * Returns dword offset of the next capability in port config space
+ * capability list and returns it. Passing %0 returns the first entry in
+ * the capability list. If no next capability is found returns %0. In case
+ * of failure returns negative errno.
+ */
+int tb_port_next_cap(struct tb_port *port, unsigned int offset)
+{
+	struct tb_cap_any header;
+	int ret;
+
+	if (!offset)
+		return port->config.first_cap_offset;
+
+	ret = tb_port_read(port, &header, TB_CFG_PORT, offset, 1);
+	if (ret)
+		return ret;
+
+	return header.basic.next;
+}
+
 static int __tb_port_find_cap(struct tb_port *port, enum tb_port_cap cap)
 {
-	u32 offset = 1;
+	int offset = 0;
 
 	do {
 		struct tb_cap_any header;
 		int ret;
 
+		offset = tb_port_next_cap(port, offset);
+		if (offset < 0)
+			return offset;
+
 		ret = tb_port_read(port, &header, TB_CFG_PORT, offset, 1);
 		if (ret)
 			return ret;
 
 		if (header.basic.cap == cap)
 			return offset;
-
-		offset = header.basic.next;
-	} while (offset);
+	} while (offset > 0);
 
 	return -ENOENT;
 }
@@ -114,6 +133,50 @@ int tb_port_find_cap(struct tb_port *port, enum tb_port_cap cap)
 }
 
 /**
+ * tb_switch_next_cap() - Return next capability in the linked list
+ * @sw: Switch to find the capability for
+ * @offset: Previous capability offset (%0 for start)
+ *
+ * Finds dword offset of the next capability in router config space
+ * capability list and returns it. Passing %0 returns the first entry in
+ * the capability list. If no next capability is found returns %0. In case
+ * of failure returns negative errno.
+ */
+int tb_switch_next_cap(struct tb_switch *sw, unsigned int offset)
+{
+	struct tb_cap_any header;
+	int ret;
+
+	if (!offset)
+		return sw->config.first_cap_offset;
+
+	ret = tb_sw_read(sw, &header, TB_CFG_SWITCH, offset, 2);
+	if (ret)
+		return ret;
+
+	switch (header.basic.cap) {
+	case TB_SWITCH_CAP_TMU:
+		ret = header.basic.next;
+		break;
+
+	case TB_SWITCH_CAP_VSE:
+		if (!header.extended_short.length)
+			ret = header.extended_long.next;
+		else
+			ret = header.extended_short.next;
+		break;
+
+	default:
+		tb_sw_dbg(sw, "unknown capability %#x at %#x\n",
+			  header.basic.cap, offset);
+		ret = -EINVAL;
+		break;
+	}
+
+	return ret >= VSE_CAP_OFFSET_MAX ? 0 : ret;
+}
+
+/**
  * tb_switch_find_cap() - Find switch capability
  * @sw Switch to find the capability for
  * @cap: Capability to look
@@ -124,21 +187,23 @@ int tb_port_find_cap(struct tb_port *port, enum tb_port_cap cap)
  */
 int tb_switch_find_cap(struct tb_switch *sw, enum tb_switch_cap cap)
 {
-	int offset = sw->config.first_cap_offset;
+	int offset = 0;
 
-	while (offset > 0 && offset < CAP_OFFSET_MAX) {
+	do {
 		struct tb_cap_any header;
 		int ret;
 
+		offset = tb_switch_next_cap(sw, offset);
+		if (offset < 0)
+			return offset;
+
 		ret = tb_sw_read(sw, &header, TB_CFG_SWITCH, offset, 1);
 		if (ret)
 			return ret;
 
 		if (header.basic.cap == cap)
 			return offset;
-
-		offset = header.basic.next;
-	}
+	} while (offset);
 
 	return -ENOENT;
 }
@@ -155,37 +220,24 @@ int tb_switch_find_cap(struct tb_switch *sw, enum tb_switch_cap cap)
  */
 int tb_switch_find_vse_cap(struct tb_switch *sw, enum tb_switch_vse_cap vsec)
 {
-	struct tb_cap_any header;
-	int offset;
+	int offset = 0;
 
-	offset = tb_switch_find_cap(sw, TB_SWITCH_CAP_VSE);
-	if (offset < 0)
-		return offset;
-
-	while (offset > 0 && offset < VSE_CAP_OFFSET_MAX) {
+	do {
+		struct tb_cap_any header;
 		int ret;
 
-		ret = tb_sw_read(sw, &header, TB_CFG_SWITCH, offset, 2);
+		offset = tb_switch_next_cap(sw, offset);
+		if (offset < 0)
+			return offset;
+
+		ret = tb_sw_read(sw, &header, TB_CFG_SWITCH, offset, 1);
 		if (ret)
 			return ret;
 
-		/*
-		 * Extended vendor specific capabilities come in two
-		 * flavors: short and long. The latter is used when
-		 * offset is over 0xff.
-		 */
-		if (offset >= CAP_OFFSET_MAX) {
-			if (header.extended_long.vsec_id == vsec)
-				return offset;
-			offset = header.extended_long.next;
-		} else {
-			if (header.extended_short.vsec_id == vsec)
-				return offset;
-			if (!header.extended_short.length)
-				return -ENOENT;
-			offset = header.extended_short.next;
-		}
-	}
+		if (header.extended_short.cap == TB_SWITCH_CAP_VSE &&
+		    header.extended_short.vsec_id == vsec)
+			return offset;
+	} while (offset);
 
 	return -ENOENT;
 }
diff --git a/drivers/thunderbolt/ctl.c b/drivers/thunderbolt/ctl.c
index 394a23ce6ca4..9894b8f63064 100644
--- a/drivers/thunderbolt/ctl.c
+++ b/drivers/thunderbolt/ctl.c
@@ -219,6 +219,7 @@ static int check_config_address(struct tb_cfg_address addr,
 static struct tb_cfg_result decode_error(const struct ctl_pkg *response)
 {
 	struct cfg_error_pkg *pkg = response->buffer;
+	struct tb_ctl *ctl = response->ctl;
 	struct tb_cfg_result res = { 0 };
 	res.response_route = tb_cfg_get_route(&pkg->header);
 	res.response_port = 0;
@@ -227,9 +228,13 @@ static struct tb_cfg_result decode_error(const struct ctl_pkg *response)
 	if (res.err)
 		return res;
 
-	WARN(pkg->zero1, "pkg->zero1 is %#x\n", pkg->zero1);
-	WARN(pkg->zero2, "pkg->zero1 is %#x\n", pkg->zero1);
-	WARN(pkg->zero3, "pkg->zero1 is %#x\n", pkg->zero1);
+	if (pkg->zero1)
+		tb_ctl_warn(ctl, "pkg->zero1 is %#x\n", pkg->zero1);
+	if (pkg->zero2)
+		tb_ctl_warn(ctl, "pkg->zero2 is %#x\n", pkg->zero2);
+	if (pkg->zero3)
+		tb_ctl_warn(ctl, "pkg->zero3 is %#x\n", pkg->zero3);
+
 	res.err = 1;
 	res.tb_error = pkg->error;
 	res.response_port = pkg->port;
@@ -266,9 +271,8 @@ static void tb_cfg_print_error(struct tb_ctl *ctl,
 		 * Invalid cfg_space/offset/length combination in
 		 * cfg_read/cfg_write.
 		 */
-		tb_ctl_WARN(ctl,
-			"CFG_ERROR(%llx:%x): Invalid config space or offset\n",
-			res->response_route, res->response_port);
+		tb_ctl_dbg(ctl, "%llx:%x: invalid config space or offset\n",
+			   res->response_route, res->response_port);
 		return;
 	case TB_CFG_ERROR_NO_SUCH_PORT:
 		/*
@@ -283,6 +287,10 @@ static void tb_cfg_print_error(struct tb_ctl *ctl,
 		tb_ctl_WARN(ctl, "CFG_ERROR(%llx:%x): Route contains a loop\n",
 			res->response_route, res->response_port);
 		return;
+	case TB_CFG_ERROR_LOCK:
+		tb_ctl_warn(ctl, "%llx:%x: downstream port is locked\n",
+			    res->response_route, res->response_port);
+		return;
 	default:
 		/* 5,6,7,9 and 11 are also valid error codes */
 		tb_ctl_WARN(ctl, "CFG_ERROR(%llx:%x): Unknown error\n",
@@ -951,6 +959,9 @@ static int tb_cfg_get_error(struct tb_ctl *ctl, enum tb_cfg_space space,
 		return -ENODEV;
 
 	tb_cfg_print_error(ctl, res);
+
+	if (res->tb_error == TB_CFG_ERROR_LOCK)
+		return -EACCES;
 	return -EIO;
 }
 
diff --git a/drivers/thunderbolt/debugfs.c b/drivers/thunderbolt/debugfs.c
new file mode 100644
index 000000000000..3680b2784ea1
--- /dev/null
+++ b/drivers/thunderbolt/debugfs.c
@@ -0,0 +1,701 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Debugfs interface
+ *
+ * Copyright (C) 2020, Intel Corporation
+ * Authors: Gil Fine <gil.fine@intel.com>
+ *	    Mika Westerberg <mika.westerberg@linux.intel.com>
+ */
+
+#include <linux/debugfs.h>
+#include <linux/pm_runtime.h>
+
+#include "tb.h"
+
+#define PORT_CAP_PCIE_LEN	1
+#define PORT_CAP_POWER_LEN	2
+#define PORT_CAP_LANE_LEN	3
+#define PORT_CAP_USB3_LEN	5
+#define PORT_CAP_DP_LEN		8
+#define PORT_CAP_TMU_LEN	8
+#define PORT_CAP_BASIC_LEN	9
+#define PORT_CAP_USB4_LEN	20
+
+#define SWITCH_CAP_TMU_LEN	26
+#define SWITCH_CAP_BASIC_LEN	27
+
+#define PATH_LEN		2
+
+#define COUNTER_SET_LEN		3
+
+#define DEBUGFS_ATTR(__space, __write)					\
+static int __space ## _open(struct inode *inode, struct file *file)	\
+{									\
+	return single_open(file, __space ## _show, inode->i_private);	\
+}									\
+									\
+static const struct file_operations __space ## _fops = {		\
+	.owner = THIS_MODULE,						\
+	.open = __space ## _open,					\
+	.release = single_release,					\
+	.read  = seq_read,						\
+	.write = __write,						\
+	.llseek = seq_lseek,						\
+}
+
+#define DEBUGFS_ATTR_RO(__space)					\
+	DEBUGFS_ATTR(__space, NULL)
+
+#define DEBUGFS_ATTR_RW(__space)					\
+	DEBUGFS_ATTR(__space, __space ## _write)
+
+static struct dentry *tb_debugfs_root;
+
+static void *validate_and_copy_from_user(const void __user *user_buf,
+					 size_t *count)
+{
+	size_t nbytes;
+	void *buf;
+
+	if (!*count)
+		return ERR_PTR(-EINVAL);
+
+	if (!access_ok(user_buf, *count))
+		return ERR_PTR(-EFAULT);
+
+	buf = (void *)get_zeroed_page(GFP_KERNEL);
+	if (!buf)
+		return ERR_PTR(-ENOMEM);
+
+	nbytes = min_t(size_t, *count, PAGE_SIZE);
+	if (copy_from_user(buf, user_buf, nbytes)) {
+		free_page((unsigned long)buf);
+		return ERR_PTR(-EFAULT);
+	}
+
+	*count = nbytes;
+	return buf;
+}
+
+static bool parse_line(char **line, u32 *offs, u32 *val, int short_fmt_len,
+		       int long_fmt_len)
+{
+	char *token;
+	u32 v[5];
+	int ret;
+
+	token = strsep(line, "\n");
+	if (!token)
+		return false;
+
+	/*
+	 * For Adapter/Router configuration space:
+	 * Short format is: offset value\n
+	 *		    v[0]   v[1]
+	 * Long format as produced from the read side:
+	 * offset relative_offset cap_id vs_cap_id value\n
+	 * v[0]   v[1]            v[2]   v[3]      v[4]
+	 *
+	 * For Counter configuration space:
+	 * Short format is: offset\n
+	 *		    v[0]
+	 * Long format as produced from the read side:
+	 * offset relative_offset counter_id value\n
+	 * v[0]   v[1]            v[2]       v[3]
+	 */
+	ret = sscanf(token, "%i %i %i %i %i", &v[0], &v[1], &v[2], &v[3], &v[4]);
+	/* In case of Counters, clear counter, "val" content is NA */
+	if (ret == short_fmt_len) {
+		*offs = v[0];
+		*val = v[short_fmt_len - 1];
+		return true;
+	} else if (ret == long_fmt_len) {
+		*offs = v[0];
+		*val = v[long_fmt_len - 1];
+		return true;
+	}
+
+	return false;
+}
+
+#if IS_ENABLED(CONFIG_USB4_DEBUGFS_WRITE)
+static ssize_t regs_write(struct tb_switch *sw, struct tb_port *port,
+			  const char __user *user_buf, size_t count,
+			  loff_t *ppos)
+{
+	struct tb *tb = sw->tb;
+	char *line, *buf;
+	u32 val, offset;
+	int ret = 0;
+
+	buf = validate_and_copy_from_user(user_buf, &count);
+	if (IS_ERR(buf))
+		return PTR_ERR(buf);
+
+	pm_runtime_get_sync(&sw->dev);
+
+	if (mutex_lock_interruptible(&tb->lock)) {
+		ret = -ERESTARTSYS;
+		goto out;
+	}
+
+	/* User did hardware changes behind the driver's back */
+	add_taint(TAINT_USER, LOCKDEP_STILL_OK);
+
+	line = buf;
+	while (parse_line(&line, &offset, &val, 2, 5)) {
+		if (port)
+			ret = tb_port_write(port, &val, TB_CFG_PORT, offset, 1);
+		else
+			ret = tb_sw_write(sw, &val, TB_CFG_SWITCH, offset, 1);
+		if (ret)
+			break;
+	}
+
+	mutex_unlock(&tb->lock);
+
+out:
+	pm_runtime_mark_last_busy(&sw->dev);
+	pm_runtime_put_autosuspend(&sw->dev);
+	free_page((unsigned long)buf);
+
+	return ret < 0 ? ret : count;
+}
+
+static ssize_t port_regs_write(struct file *file, const char __user *user_buf,
+			       size_t count, loff_t *ppos)
+{
+	struct seq_file *s = file->private_data;
+	struct tb_port *port = s->private;
+
+	return regs_write(port->sw, port, user_buf, count, ppos);
+}
+
+static ssize_t switch_regs_write(struct file *file, const char __user *user_buf,
+				 size_t count, loff_t *ppos)
+{
+	struct seq_file *s = file->private_data;
+	struct tb_switch *sw = s->private;
+
+	return regs_write(sw, NULL, user_buf, count, ppos);
+}
+#define DEBUGFS_MODE		0600
+#else
+#define port_regs_write		NULL
+#define switch_regs_write	NULL
+#define DEBUGFS_MODE		0400
+#endif
+
+static int port_clear_all_counters(struct tb_port *port)
+{
+	u32 *buf;
+	int ret;
+
+	buf = kcalloc(COUNTER_SET_LEN * port->config.max_counters, sizeof(u32),
+		      GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	ret = tb_port_write(port, buf, TB_CFG_COUNTERS, 0,
+			    COUNTER_SET_LEN * port->config.max_counters);
+	kfree(buf);
+
+	return ret;
+}
+
+static ssize_t counters_write(struct file *file, const char __user *user_buf,
+			      size_t count, loff_t *ppos)
+{
+	struct seq_file *s = file->private_data;
+	struct tb_port *port = s->private;
+	struct tb_switch *sw = port->sw;
+	struct tb *tb = port->sw->tb;
+	char *buf;
+	int ret;
+
+	buf = validate_and_copy_from_user(user_buf, &count);
+	if (IS_ERR(buf))
+		return PTR_ERR(buf);
+
+	pm_runtime_get_sync(&sw->dev);
+
+	if (mutex_lock_interruptible(&tb->lock)) {
+		ret = -ERESTARTSYS;
+		goto out;
+	}
+
+	/* If written delimiter only, clear all counters in one shot */
+	if (buf[0] == '\n') {
+		ret = port_clear_all_counters(port);
+	} else  {
+		char *line = buf;
+		u32 val, offset;
+
+		ret = -EINVAL;
+		while (parse_line(&line, &offset, &val, 1, 4)) {
+			ret = tb_port_write(port, &val, TB_CFG_COUNTERS,
+					    offset, 1);
+			if (ret)
+				break;
+		}
+	}
+
+	mutex_unlock(&tb->lock);
+
+out:
+	pm_runtime_mark_last_busy(&sw->dev);
+	pm_runtime_put_autosuspend(&sw->dev);
+	free_page((unsigned long)buf);
+
+	return ret < 0 ? ret : count;
+}
+
+static void cap_show(struct seq_file *s, struct tb_switch *sw,
+		     struct tb_port *port, unsigned int cap, u8 cap_id,
+		     u8 vsec_id, int length)
+{
+	int ret, offset = 0;
+
+	while (length > 0) {
+		int i, dwords = min(length, TB_MAX_CONFIG_RW_LENGTH);
+		u32 data[TB_MAX_CONFIG_RW_LENGTH];
+
+		if (port)
+			ret = tb_port_read(port, data, TB_CFG_PORT, cap + offset,
+					   dwords);
+		else
+			ret = tb_sw_read(sw, data, TB_CFG_SWITCH, cap + offset, dwords);
+		if (ret) {
+			seq_printf(s, "0x%04x <not accessible>\n",
+				   cap + offset);
+			if (dwords > 1)
+				seq_printf(s, "0x%04x ...\n", cap + offset + 1);
+			return;
+		}
+
+		for (i = 0; i < dwords; i++) {
+			seq_printf(s, "0x%04x %4d 0x%02x 0x%02x 0x%08x\n",
+				   cap + offset + i, offset + i,
+				   cap_id, vsec_id, data[i]);
+		}
+
+		length -= dwords;
+		offset += dwords;
+	}
+}
+
+static void port_cap_show(struct tb_port *port, struct seq_file *s,
+			  unsigned int cap)
+{
+	struct tb_cap_any header;
+	u8 vsec_id = 0;
+	size_t length;
+	int ret;
+
+	ret = tb_port_read(port, &header, TB_CFG_PORT, cap, 1);
+	if (ret) {
+		seq_printf(s, "0x%04x <capability read failed>\n", cap);
+		return;
+	}
+
+	switch (header.basic.cap) {
+	case TB_PORT_CAP_PHY:
+		length = PORT_CAP_LANE_LEN;
+		break;
+
+	case TB_PORT_CAP_TIME1:
+		length = PORT_CAP_TMU_LEN;
+		break;
+
+	case TB_PORT_CAP_POWER:
+		length = PORT_CAP_POWER_LEN;
+		break;
+
+	case TB_PORT_CAP_ADAP:
+		if (tb_port_is_pcie_down(port) || tb_port_is_pcie_up(port)) {
+			length = PORT_CAP_PCIE_LEN;
+		} else if (tb_port_is_dpin(port) || tb_port_is_dpout(port)) {
+			length = PORT_CAP_DP_LEN;
+		} else if (tb_port_is_usb3_down(port) ||
+			   tb_port_is_usb3_up(port)) {
+			length = PORT_CAP_USB3_LEN;
+		} else {
+			seq_printf(s, "0x%04x <unsupported capability 0x%02x>\n",
+				   cap, header.basic.cap);
+			return;
+		}
+		break;
+
+	case TB_PORT_CAP_VSE:
+		if (!header.extended_short.length) {
+			ret = tb_port_read(port, (u32 *)&header + 1, TB_CFG_PORT,
+					   cap + 1, 1);
+			if (ret) {
+				seq_printf(s, "0x%04x <capability read failed>\n",
+					   cap + 1);
+				return;
+			}
+			length = header.extended_long.length;
+			vsec_id = header.extended_short.vsec_id;
+		} else {
+			length = header.extended_short.length;
+			vsec_id = header.extended_short.vsec_id;
+			/*
+			 * Ice Lake and Tiger Lake do not implement the
+			 * full length of the capability, only first 32
+			 * dwords so hard-code it here.
+			 */
+			if (!vsec_id &&
+			    (tb_switch_is_ice_lake(port->sw) ||
+			     tb_switch_is_tiger_lake(port->sw)))
+				length = 32;
+		}
+		break;
+
+	case TB_PORT_CAP_USB4:
+		length = PORT_CAP_USB4_LEN;
+		break;
+
+	default:
+		seq_printf(s, "0x%04x <unsupported capability 0x%02x>\n",
+			   cap, header.basic.cap);
+		return;
+	}
+
+	cap_show(s, NULL, port, cap, header.basic.cap, vsec_id, length);
+}
+
+static void port_caps_show(struct tb_port *port, struct seq_file *s)
+{
+	int cap;
+
+	cap = tb_port_next_cap(port, 0);
+	while (cap > 0) {
+		port_cap_show(port, s, cap);
+		cap = tb_port_next_cap(port, cap);
+	}
+}
+
+static int port_basic_regs_show(struct tb_port *port, struct seq_file *s)
+{
+	u32 data[PORT_CAP_BASIC_LEN];
+	int ret, i;
+
+	ret = tb_port_read(port, data, TB_CFG_PORT, 0, ARRAY_SIZE(data));
+	if (ret)
+		return ret;
+
+	for (i = 0; i < ARRAY_SIZE(data); i++)
+		seq_printf(s, "0x%04x %4d 0x00 0x00 0x%08x\n", i, i, data[i]);
+
+	return 0;
+}
+
+static int port_regs_show(struct seq_file *s, void *not_used)
+{
+	struct tb_port *port = s->private;
+	struct tb_switch *sw = port->sw;
+	struct tb *tb = sw->tb;
+	int ret;
+
+	pm_runtime_get_sync(&sw->dev);
+
+	if (mutex_lock_interruptible(&tb->lock)) {
+		ret = -ERESTARTSYS;
+		goto out_rpm_put;
+	}
+
+	seq_puts(s, "# offset relative_offset cap_id vs_cap_id value\n");
+
+	ret = port_basic_regs_show(port, s);
+	if (ret)
+		goto out_unlock;<