Merge tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Don't destroy user event fields when removal fails

   User event fields are destroyed before the event is removed from
   visibility. But that can fail leaving the still visible event with no
   fields. Move the destroying of the fields to after the event is
   successfully removed from visibility.

 - Initialize function graph state is fork before calling
   copy_exec_state()

   For non-CLONE_VM forks, copy_exec_state() allocates a new
   task_exec_state. If that allocation fails, ftrace_graph_exit_task()
   will free the tasks ret_stack pointer. Since that pointer is still
   using the parent's ret_stack, it mistakenly frees the parent's
   pointer too.

   Call ftrace_graph_init() on the task first which will NULL out the
   new tasks's ret_stack and if the copy fails, it will not free
   anything.

 - Remove FGRAPH_MAX_INDEX

   The macro FGRAPH_MAX_INDEX was added but never used. Remove it.

 - Save ent_size in function graph printing of nested functions

   The function graph tracer needs to look at the next event to see if
   the next event is the return of the current function entry. If it is,
   it prints a single line:

	ktime_get();

   Otherwise it prints it like a nested function:

	tick_nohz_irq_exit() {
	    ktime_get();
	    kcpustat_irq_exit();
	}

   In order to look at the next event, it must save the current event so
   that it has the information to print from it. It saves the event in
   the iterator descriptor called "ent". What it doesn't save is the
   ent_size of the event which is now used to know if the function graph
   arguments are to be printed. The peek doesn't save the size so the
   size used happens to be that of the size of the last event that was
   seen.

   Save the entry event size in the iterator descriptor so that the
   correct size is used.

 - Fix several errors with freeing data in the histogram code

   The histogram code had a lot of leaked or or incorrect accounting
   when failures happen. Correct them.

 - Fix histogram regression of .percent and .graph modifiers

   Up until 6.3 histogram values could have "percent" or "graph"
   modifiers that changed how they were printed. But a change that added
   restricting histograms values from being strings, stack traces and
   other modifiers inadvertently prevented them from using the percent
   and graph modifiers, which were legal use cases for values.

   Put back the percent and graph modifiers.

 - Fix various typos in the comments

 - Set the trace_clock before initializing a histogram with clock
   argument

   The histogram API allows the user to specific which trace clock to
   use via a "clock=" string. The histogram is set up first before the
   clock is checked. If the passed in clock is not valid, it exits
   without fully fixing up the histogram leaving it on the list and a
   use-after-free can trigger.

   Update the clock argument first and if it fails then exit gracefully
   before the histogram trigger is placed on any lists.

 - Restore :mod: trailer after parsing in ftrace_set_clr_event

   The function ftrace_set_clr_event() modifies the parse string and
   needs to put it back to what was passed in. It searches for ":mod:"
   via a strsep() but fails to put back the first ':' in the string.

   Add back the ':' in the passed in string.

 - Take trace_array reference when opening a tracer options file

   The options files are dynamically created and some tracers add their
   own options. When a tracer adds their own list of options, the
   trace_array holding them has an array to hold the list of options for
   each tracer. This array increases in size via a krealloc(), and the
   new entry gets a newly allocated array to hold the options of the new
   tracer being added.

   The element in each entry of the tracer's option array holds a
   pointer back to the trace_array, a pointer to the tracer it is
   associated to, a pointer to the flags of the option.

   The issue is that these arrays are freed when the trace_array is
   freed when its instance it represents is removed from the instances
   directory. There's a race that an open of one of these options files
   can happen when the instance is being removed.

   Add a new helper function to be called by the open function of the
   options file to iterate all existing trace_arrays under a lock and
   find the one that has the given option element in one of it's tracer
   arrays. If found, then update the associated trace_array's reference
   counter to keep it from being freed. If not found, have the open call
   return -ENODEV.

 - Disable interrupts when acquiring the lock in rb_wake_up_waiters()

   The function rb_wake_up_waiters() assumes it will be called in
   interrupt context and does not disable irqs when taking
   cpu_buffer->reader_lock, which can be called in hard interrupt
   context. The issue is in PREEMPT_RT, this function is called in
   thread context leaving this lock open to a deadlock.

   Take the lock with interrupts disabled.

 - Use rcu_assign_pointer() for tmp_ops filter hash

   The tmp_ops used in update_ftrace_direct_mod() assigns its
   filter_hash field directly, but that field is annotated as __rcu and
   sparse complains. Assign it with rcu_assign_pointer()

 - Fix use-after-free in enable_trigger_private_data_free()

   The trace_event_call is accessed through the event_trigger_data's
   trace_event_file pointer to put the trace_event_call on freeing. The
   issue is that the trace_event_file data may have been freed already
   causing a use-after-free. Add a field to the event_trigger_data that
   points directly to the trace_event_call so that it can decrement its
   reference directly without needing to go through the
   trace_event_file.

 - Fix accounting of buffer data remote headers

   trace_buffer_desc_size() and trace_remote_alloc_buffer() undercount
   the number of pages is needed for the asked for size as it doesn't
   take into account the meta data on each page. Add a helper function
   to do the calculation properly and use that in these functions.

 - Catch nr_page_va overflow in ring_buffer_desc sizing

   The number of pages per remote ring buffer is capped by
   ring_buffer_desc::nr_page_va (32 bits). A buffer_size large enough to
   overflow that field would silently allocate a descriptor smaller than
   what was asked for.

 - Do not resize the subbuf order if any per_cpu buffer is disabled

   The mmapping of ring buffers disables resizing the subbuffers, but it
   is done per-cpu whereas the subbuf size change is done for all the
   per_cpu buffers under the buffer->mutex. It could change the size of
   some while the mapping is happening on others. Have the resize of the
   subbuf order check all the per_cpu buffers under the lock to see if
   any of them is disabled before starting and causing an inconsistency
   between buffers that are being mapped.

* tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (25 commits)
  ring-buffer: Check resize_disabled before publishing the new subbuf order
  tracing/remotes: Catch nr_page_va overflow in ring_buffer_desc sizing
  tracing/remotes: Account for ring buffer page header in size calculation
  tracing: Don't dereference trace_event_file in deferred trigger free
  ftrace: Use rcu_assign_pointer() for tmp_ops filter hash
  ring-buffer: Acquire the lock with irqsave in rb_wake_up_waiters()
  tracing: Take trace_array reference when opening a tracer options file
  tracing: Fix ring_buffer_read_page_size() kernel-doc
  tracing: Restore :mod: trailer after parsing in ftrace_set_clr_event()
  tracing: Fix memory corruption from a "STACKTRACE" histogram key
  tracing: Fix memory corruption from the histogram stacktrace modifier
  tracing: Undo the registration when enabling the histogram trigger fails
  tracing: Take the reference before publishing the named histogram trigger
  tracing: Set the trace clock before registering the histogram trigger
  tracing: Fix typo "preceeded" in comment
  tracing: Fix typo "availabe" in comment
  tracing: Let histogram values keep the percent and graph modifiers
  tracing: Keep the entry count when the histogram stats allocation fails
  tracing: Free histogram the field rejected for a bad modifier
  tracing: Free histogram the var ref when its initialization fails
  ...

1 files changed, 2563 insertions, 0 deletions

diff --git a/drivers/thunderbolt/debugfs.c b/drivers/thunderbolt/debugfs.c
new file mode 100644
index 000000000..6e9080e7b
--- /dev/null
+++ b/drivers/thunderbolt/debugfs.c
@@ -0,0 +1,2563 @@
+// 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/array_size.h>
+#include <linux/bitfield.h>
+#include <linux/debugfs.h>
+#include <linux/delay.h>
+#include <linux/pm_runtime.h>
+#include <linux/string_choices.h>
+#include <linux/uaccess.h>
+
+#include "tb.h"
+#include "sb_regs.h"
+
+#define PORT_CAP_V1_PCIE_LEN	1
+#define PORT_CAP_V2_PCIE_LEN	2
+#define PORT_CAP_POWER_LEN	2
+#define PORT_CAP_LANE_LEN	3
+#define PORT_CAP_USB3_LEN	5
+#define PORT_CAP_DP_V1_LEN	9
+#define PORT_CAP_DP_V2_LEN	14
+#define PORT_CAP_TMU_V1_LEN	8
+#define PORT_CAP_TMU_V2_LEN	10
+#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
+
+/*
+ * USB4 spec doesn't specify dwell range, the range of 100 ms to 500 ms
+ * probed to give good results.
+ */
+#define MIN_DWELL_TIME		100 /* ms */
+#define MAX_DWELL_TIME		500 /* ms */
+#define DWELL_SAMPLE_INTERVAL	10
+
+enum usb4_margin_cap_voltage_indp {
+	USB4_MARGIN_CAP_VOLTAGE_INDP_GEN_2_3_MIN,
+	USB4_MARGIN_CAP_VOLTAGE_INDP_GEN_2_3_HL,
+	USB4_MARGIN_CAP_VOLTAGE_INDP_GEN_2_3_BOTH,
+	USB4_MARGIN_CAP_VOLTAGE_INDP_GEN_4_MIN,
+	USB4_MARGIN_CAP_VOLTAGE_INDP_GEN_4_BOTH,
+	USB4_MARGIN_CAP_VOLTAGE_INDP_UNKNOWN,
+};
+
+enum usb4_margin_cap_time_indp {
+	USB4_MARGIN_CAP_TIME_INDP_GEN_2_3_MIN,
+	USB4_MARGIN_CAP_TIME_INDP_GEN_2_3_LR,
+	USB4_MARGIN_CAP_TIME_INDP_GEN_2_3_BOTH,
+	USB4_MARGIN_CAP_TIME_INDP_GEN_4_MIN,
+	USB4_MARGIN_CAP_TIME_INDP_GEN_4_BOTH,
+	USB4_MARGIN_CAP_TIME_INDP_UNKNOWN,
+};
+
+/* Sideband registers and their sizes as defined in the USB4 spec */
+struct sb_reg {
+	unsigned int reg;
+	unsigned int size;
+};
+
+#define SB_MAX_SIZE		64
+
+/* Sideband registers for router */
+static const struct sb_reg port_sb_regs[] = {
+	{ USB4_SB_VENDOR_ID, 4 },
+	{ USB4_SB_PRODUCT_ID, 4 },
+	{ USB4_SB_DEBUG_CONF, 4 },
+	{ USB4_SB_DEBUG, 54 },
+	{ USB4_SB_LRD_TUNING, 4 },
+	{ USB4_SB_OPCODE, 4 },
+	{ USB4_SB_METADATA, 4 },
+	{ USB4_SB_LINK_CONF, 3 },
+	{ USB4_SB_GEN23_TXFFE, 4 },
+	{ USB4_SB_GEN4_TXFFE, 4 },
+	{ USB4_SB_VERSION, 4 },
+	{ USB4_SB_DATA, 64 },
+};
+
+/* Sideband registers for retimer */
+static const struct sb_reg retimer_sb_regs[] = {
+	{ USB4_SB_VENDOR_ID, 4 },
+	{ USB4_SB_PRODUCT_ID, 4 },
+	{ USB4_SB_FW_VERSION, 4 },
+	{ USB4_SB_LRD_TUNING, 4 },
+	{ USB4_SB_OPCODE, 4 },
+	{ USB4_SB_METADATA, 4 },
+	{ USB4_SB_GEN23_TXFFE, 4 },
+	{ USB4_SB_GEN4_TXFFE, 4 },
+	{ USB4_SB_VERSION, 4 },
+	{ USB4_SB_DATA, 64 },
+};
+
+#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 = kzalloc(PAGE_SIZE, GFP_KERNEL);
+	if (!buf)
+		return ERR_PTR(-ENOMEM);
+
+	nbytes = min_t(size_t, *count, PAGE_SIZE);
+	if (copy_from_user(buf, user_buf, nbytes)) {
+		kfree(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 Path configuration space:
+	 * Short format is: offset value\n
+	 *		    v[0]   v[1]
+	 * Long format as produced from the read side:
+	 * offset relative_offset in_hop_id value\n
+	 * v[0]   v[1]            v[2]      v[3]
+	 *
+	 * 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)
+/*
+ * Path registers need to be written in double word pairs and they both must be
+ * read before written. This writes one double word in path config space
+ * following the spec flow.
+ */
+static int path_write_one(struct tb_port *port, u32 val, u32 offset)
+{
+	u32 index = offset % PATH_LEN;
+	u32 offs = offset - index;
+	u32 data[PATH_LEN];
+	int ret;
+
+	ret = tb_port_read(port, data, TB_CFG_HOPS, offs, PATH_LEN);
+	if (ret)
+		return ret;
+	data[index] = val;
+	return tb_port_write(port, data, TB_CFG_HOPS, offs, PATH_LEN);
+}
+
+static ssize_t regs_write(struct tb_switch *sw, struct tb_port *port,
+			  enum tb_cfg_space space, const char __user *user_buf,
+			  size_t count, loff_t *ppos)
+{
+	int long_fmt_len, ret = 0;
+	struct tb *tb = sw->tb;
+	char *line, *buf;
+	u32 val, offset;
+
+	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);
+
+	if (space == TB_CFG_HOPS)
+		long_fmt_len = 4;
+	else
+		long_fmt_len = 5;
+
+	line = buf;
+	while (parse_line(&line, &offset, &val, 2, long_fmt_len)) {
+		if (port) {
+			if (space == TB_CFG_HOPS)
+				ret = path_write_one(port, val, offset);
+			else
+				ret = tb_port_write(port, &val, space, 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);
+	kfree(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, TB_CFG_PORT, user_buf, count, ppos);
+}
+
+static ssize_t path_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, TB_CFG_HOPS, 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, TB_CFG_SWITCH, user_buf, count, ppos);
+}
+
+static bool parse_sb_line(char **line, u8 *reg, u8 *data, size_t data_size,
+			  size_t *bytes_read)
+{
+	char *field, *token;
+	int i;
+
+	token = strsep(line, "\n");
+	if (!token)
+		return false;
+
+	/* Parse the register first */
+	field = strsep(&token, " ");
+	if (!field)
+		return false;
+	if (kstrtou8(field, 0, reg))
+		return false;
+
+	/* Then the values for the register, up to data_size */
+	for (i = 0; i < data_size; i++) {
+		field = strsep(&token, " ");
+		if (!field)
+			break;
+		if (kstrtou8(field, 0, &data[i]))
+			return false;
+	}
+
+	*bytes_read = i;
+	return true;
+}
+
+static ssize_t sb_regs_write(struct tb_port *port, const struct sb_reg *sb_regs,
+			     size_t size, enum usb4_sb_target target, u8 index,
+			     char *buf, size_t count, loff_t *ppos)
+{
+	u8 reg, data[SB_MAX_SIZE];
+	size_t bytes_read;
+	char *line = buf;
+
+	/* User did hardware changes behind the driver's back */
+	add_taint(TAINT_USER, LOCKDEP_STILL_OK);
+
+	/*
+	 * For sideband registers we accept:
+	 * reg b0 b1 b2...\n
+	 *
+	 * Here "reg" is the byte offset of the sideband register and "b0"..
+	 * are the byte values. There can be less byte values than the register
+	 * size. The leftovers will not be overwritten.
+	 */
+	while (parse_sb_line(&line, &reg, data, ARRAY_SIZE(data), &bytes_read)) {
+		const struct sb_reg *sb_reg;
+		int ret;
+
+		/* At least one byte must be passed */
+		if (bytes_read < 1)
+			return -EINVAL;
+
+		/* Find the register */
+		sb_reg = NULL;
+		for (int i = 0; i < size; i++) {
+			if (sb_regs[i].reg == reg) {
+				sb_reg = &sb_regs[i];
+				break;
+			}
+		}
+
+		if (!sb_reg)
+			return -EINVAL;
+
+		if (bytes_read > sb_reg->size)
+			return -E2BIG;
+
+		ret = usb4_port_sb_write(port, target, index, sb_reg->reg, data,
+					 bytes_read);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static ssize_t port_sb_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;
+	struct tb_switch *sw = port->sw;
+	struct tb *tb = 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;
+	}
+
+	ret = sb_regs_write(port, port_sb_regs, ARRAY_SIZE(port_sb_regs),
+			    USB4_SB_TARGET_ROUTER, 0, buf, count, ppos);
+
+	mutex_unlock(&tb->lock);
+out:
+	pm_runtime_mark_last_busy(&sw->dev);
+	pm_runtime_put_autosuspend(&sw->dev);
+	kfree(buf);
+
+	return ret < 0 ? ret : count;
+}
+
+static ssize_t retimer_sb_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_retimer *rt = s->private;
+	struct tb *tb = rt->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(&rt->dev);
+
+	if (mutex_lock_interruptible(&tb->lock)) {
+		ret = -ERESTARTSYS;
+		goto out;
+	}
+
+	ret = sb_regs_write(rt->port, retimer_sb_regs, ARRAY_SIZE(retimer_sb_regs),
+			    USB4_SB_TARGET_RETIMER, rt->index, buf, count, ppos);
+
+	mutex_unlock(&tb->lock);
+out:
+	pm_runtime_mark_last_busy(&rt->dev);
+	pm_runtime_put_autosuspend(&rt->dev);
+	kfree(buf);
+
+	return ret < 0 ? ret : count;
+}
+#define DEBUGFS_MODE		0600
+#else
+#define port_regs_write		NULL
+#define path_write		NULL
+#define switch_regs_write	NULL
+#define port_sb_regs_write	NULL
+#define retimer_sb_regs_write	NULL
+#define DEBUGFS_MODE		0400
+#endif
+
+#if IS_ENABLED(CONFIG_USB4_DEBUGFS_MARGINING)
+/**
+ * struct tb_margining - Lane margining support
+ * @port: USB4 port through which the margining operations are run
+ * @target: Sideband target
+ * @index: Retimer index if taget is %USB4_SB_TARGET_RETIMER
+ * @dev: Pointer to the device that is the target (USB4 port or retimer)
+ * @gen: Link generation
+ * @asym_rx: %true% if @port supports asymmetric link with 3 Rx
+ * @caps: Port lane margining capabilities
+ * @results: Last lane margining results
+ * @lanes: %0, %1 or %7 (all)
+ * @min_ber_level: Minimum supported BER level contour value
+ * @max_ber_level: Maximum supported BER level contour value
+ * @ber_level: Current BER level contour value
+ * @voltage_steps: Number of mandatory voltage steps
+ * @max_voltage_offset: Maximum mandatory voltage offset (in mV)
+ * @voltage_steps_optional_range: Number of voltage steps for optional range
+ * @max_voltage_offset_optional_range: Maximum voltage offset for the optional
+ *					range (in mV).
+ * @time_steps: Number of time margin steps
+ * @max_time_offset: Maximum time margin offset (in mUI)
+ * @voltage_time_offset: Offset for voltage / time for software margining
+ * @dwell_time: Dwell time for software margining (in ms)
+ * @error_counter: Error counter operation for software margining
+ * @optional_voltage_offset_range: Enable optional extended voltage range
+ * @software: %true if software margining is used instead of hardware
+ * @time: %true if time margining is used instead of voltage
+ * @right_high: %false if left/low margin test is performed, %true if
+ *		right/high
+ * @upper_eye: %false if the lower PAM3 eye is used, %true if the upper
+ *	       eye is used
+ */
+struct tb_margining {
+	struct tb_port *port;
+	enum usb4_sb_target target;
+	u8 index;
+	struct device *dev;
+	unsigned int gen;
+	bool asym_rx;
+	u32 caps[3];
+	u32 results[3];
+	enum usb4_margining_lane lanes;
+	unsigned int min_ber_level;
+	unsigned int max_ber_level;
+	unsigned int ber_level;
+	unsigned int voltage_steps;
+	unsigned int max_voltage_offset;
+	unsigned int voltage_steps_optional_range;
+	unsigned int max_voltage_offset_optional_range;
+	unsigned int time_steps;
+	unsigned int max_time_offset;
+	unsigned int voltage_time_offset;
+	unsigned int dwell_time;
+	enum usb4_margin_sw_error_counter error_counter;
+	bool optional_voltage_offset_range;
+	bool software;
+	bool time;
+	bool right_high;
+	bool upper_eye;
+};
+
+static int margining_modify_error_counter(struct tb_margining *margining,
+	u32 lanes, enum usb4_margin_sw_error_counter error_counter)
+{
+	struct usb4_port_margining_params params = { 0 };
+	struct tb_port *port = margining->port;
+	u32 result;
+
+	if (error_counter != USB4_MARGIN_SW_ERROR_COUNTER_CLEAR &&
+	    error_counter != USB4_MARGIN_SW_ERROR_COUNTER_STOP)
+		return -EOPNOTSUPP;
+
+	params.error_counter = error_counter;
+	params.lanes = lanes;
+
+	return usb4_port_sw_margin(port, margining->target, margining->index,
+				   &params, &result);
+}
+
+static bool supports_software(const struct tb_margining *margining)
+{
+	if (margining->gen < 4)
+		return margining->caps[0] & USB4_MARGIN_CAP_0_MODES_SW;
+	return margining->caps[2] & USB4_MARGIN_CAP_2_MODES_SW;
+}
+
+static bool supports_hardware(const struct tb_margining *margining)
+{
+	if (margining->gen < 4)
+		return margining->caps[0] & USB4_MARGIN_CAP_0_MODES_HW;
+	return margining->caps[2] & USB4_MARGIN_CAP_2_MODES_HW;
+}
+
+static bool all_lanes(const struct tb_margining *margining)
+{
+	return margining->caps[0] & USB4_MARGIN_CAP_0_ALL_LANES;
+}
+
+static enum usb4_margin_cap_voltage_indp
+independent_voltage_margins(const struct tb_margining *margining)
+{
+	if (margining->gen < 4) {
+		switch (FIELD_GET(USB4_MARGIN_CAP_0_VOLTAGE_INDP_MASK, margining->caps[0])) {
+		case USB4_MARGIN_CAP_0_VOLTAGE_MIN:
+			return USB4_MARGIN_CAP_VOLTAGE_INDP_GEN_2_3_MIN;
+		case USB4_MARGIN_CAP_0_VOLTAGE_HL:
+			return USB4_MARGIN_CAP_VOLTAGE_INDP_GEN_2_3_HL;
+		case USB4_MARGIN_CAP_1_TIME_BOTH:
+			return USB4_MARGIN_CAP_VOLTAGE_INDP_GEN_2_3_BOTH;
+		}
+	} else {
+		switch (FIELD_GET(USB4_MARGIN_CAP_2_VOLTAGE_INDP_MASK, margining->caps[2])) {
+		case USB4_MARGIN_CAP_2_VOLTAGE_MIN:
+			return USB4_MARGIN_CAP_VOLTAGE_INDP_GEN_4_MIN;
+		case USB4_MARGIN_CAP_2_VOLTAGE_BOTH:
+			return USB4_MARGIN_CAP_VOLTAGE_INDP_GEN_4_BOTH;
+		}
+	}
+	return USB4_MARGIN_CAP_VOLTAGE_INDP_UNKNOWN;
+}
+
+static bool supports_time(const struct tb_margining *margining)
+{
+	if (margining->gen < 4)
+		return margining->caps[0] & USB4_MARGIN_CAP_0_TIME;
+	return margining->caps[2] & USB4_MARGIN_CAP_2_TIME;
+}
+
+/* Only applicable if supports_time() returns true */
+static enum usb4_margin_cap_time_indp
+independent_time_margins(const struct tb_margining *margining)
+{
+	if (margining->gen < 4) {
+		switch (FIELD_GET(USB4_MARGIN_CAP_1_TIME_INDP_MASK, margining->caps[1])) {
+		case USB4_MARGIN_CAP_1_TIME_MIN:
+			return USB4_MARGIN_CAP_TIME_INDP_GEN_2_3_MIN;
+		case USB4_MARGIN_CAP_1_TIME_LR:
+			return USB4_MARGIN_CAP_TIME_INDP_GEN_2_3_LR;
+		case USB4_MARGIN_CAP_1_TIME_BOTH:
+			return USB4_MARGIN_CAP_TIME_INDP_GEN_2_3_BOTH;
+		}
+	} else {
+		switch (FIELD_GET(USB4_MARGIN_CAP_2_TIME_INDP_MASK, margining->caps[2])) {
+		case USB4_MARGIN_CAP_2_TIME_MIN:
+			return USB4_MARGIN_CAP_TIME_INDP_GEN_4_MIN;
+		case USB4_MARGIN_CAP_2_TIME_BOTH:
+			return USB4_MARGIN_CAP_TIME_INDP_GEN_4_BOTH;
+		}
+	}
+	return USB4_MARGIN_CAP_TIME_INDP_UNKNOWN;
+}
+
+static bool
+supports_optional_voltage_offset_range(const struct tb_margining *margining)
+{
+	return margining->caps[0] & USB4_MARGIN_CAP_0_OPT_VOLTAGE_SUPPORT;
+}
+
+static ssize_t
+margining_ber_level_write(struct file *file, const char __user *user_buf,
+			   size_t count, loff_t *ppos)
+{
+	struct seq_file *s = file->private_data;
+	struct tb_margining *margining = s->private;
+	struct tb *tb = margining->port->sw->tb;
+	unsigned int val;
+	int ret = 0;
+	char *buf;
+
+	if (mutex_lock_interruptible(&tb->lock))
+		return -ERESTARTSYS;
+
+	if (margining->software) {
+		ret = -EINVAL;
+		goto out_unlock;
+	}
+
+	buf = validate_and_copy_from_user(user_buf, &count);
+	if (IS_ERR(buf)) {
+		ret = PTR_ERR(buf);
+		goto out_unlock;
+	}
+
+	buf[count - 1] = '\0';
+
+	ret = kstrtouint(buf, 10, &val);
+	if (ret)
+		goto out_free;
+
+	if (val < margining->min_ber_level ||
+	    val > margining->max_ber_level) {
+		ret = -EINVAL;
+		goto out_free;
+	}
+
+	margining->ber_level = val;
+
+out_free:
+	kfree(buf);
+out_unlock:
+	mutex_unlock(&tb->lock);
+
+	return ret < 0 ? ret : count;
+}
+
+static void ber_level_show(struct seq_file *s, unsigned int val)
+{
+	if (val % 2)
+		seq_printf(s, "3 * 1e%d (%u)\n", -12 + (val + 1) / 2, val);
+	else
+		seq_printf(s, "1e%d (%u)\n", -12 + val / 2, val);
+}
+
+static int margining_ber_level_show(struct seq_file *s, void *not_used)
+{
+	const struct tb_margining *margining = s->private;
+
+	if (margining->software)
+		return -EINVAL;
+	ber_level_show(s, margining->ber_level);
+	return 0;
+}
+DEBUGFS_ATTR_RW(margining_ber_level);
+
+static int margining_caps_show(struct seq_file *s, void *not_used)
+{
+	struct tb_margining *margining = s->private;
+	struct tb *tb = margining->port->sw->tb;
+	int ret = 0;
+
+	if (mutex_lock_interruptible(&tb->lock))
+		return -ERESTARTSYS;
+
+	/* Dump the raw caps first */
+	for (int i = 0; i < ARRAY_SIZE(margining->caps); i++)
+		seq_printf(s, "0x%08x\n", margining->caps[i]);
+
+	seq_printf(s, "# software margining: %s\n",
+		   str_yes_no(supports_software(margining)));
+	if (supports_hardware(margining)) {
+		seq_puts(s, "# hardware margining: yes\n");
+		seq_puts(s, "# minimum BER level contour: ");
+		ber_level_show(s, margining->min_ber_level);
+		seq_puts(s, "# maximum BER level contour: ");
+		ber_level_show(s, margining->max_ber_level);
+	} else {
+		seq_puts(s, "# hardware margining: no\n");
+	}
+
+	seq_printf(s, "# all lanes simultaneously: %s\n",
+		  str_yes_no(all_lanes(margining)));
+	seq_printf(s, "# voltage margin steps: %u\n",
+		   margining->voltage_steps);
+	seq_printf(s, "# maximum voltage offset: %u mV\n",
+		   margining->max_voltage_offset);
+	seq_printf(s, "# optional voltage offset range support: %s\n",
+		   str_yes_no(supports_optional_voltage_offset_range(margining)));
+	if (supports_optional_voltage_offset_range(margining)) {
+		seq_printf(s, "# voltage margin steps, optional range: %u\n",
+			   margining->voltage_steps_optional_range);
+		seq_printf(s, "# maximum voltage offset, optional range: %u mV\n",
+			   margining->max_voltage_offset_optional_range);
+	}
+
+	switch (independent_voltage_margins(margining)) {
+	case USB4_MARGIN_CAP_VOLTAGE_INDP_GEN_2_3_MIN:
+		seq_puts(s, "# returns minimum between high and low voltage margins\n");
+		break;
+	case USB4_MARGIN_CAP_VOLTAGE_INDP_GEN_2_3_HL:
+		seq_puts(s, "# returns high or low voltage margin\n");
+		break;
+	case USB4_MARGIN_CAP_VOLTAGE_INDP_GEN_2_3_BOTH:
+		seq_puts(s, "# returns both high and low margins\n");
+		break;
+	case USB4_MARGIN_CAP_VOLTAGE_INDP_GEN_4_MIN:
+		seq_puts(s, "# returns minimum between high and low voltage margins in both lower and upper eye\n");
+		break;
+	case USB4_MARGIN_CAP_VOLTAGE_INDP_GEN_4_BOTH:
+		seq_puts(s, "# returns both high and low margins of both upper and lower eye\n");
+		break;
+	case USB4_MARGIN_CAP_VOLTAGE_INDP_UNKNOWN:
+		tb_port_warn(margining->port,
+			     "failed to parse independent voltage margining capabilities\n");
+		ret = -EIO;
+		goto out;
+	}
+
+	if (supports_time(margining)) {
+		seq_puts(s, "# time margining: yes\n");
+		seq_printf(s, "# time margining is destructive: %s\n",
+			   str_yes_no(margining->caps[1] & USB4_MARGIN_CAP_1_TIME_DESTR));
+
+		switch (independent_time_margins(margining)) {
+		case USB4_MARGIN_CAP_TIME_INDP_GEN_2_3_MIN:
+			seq_puts(s, "# returns minimum between left and right time margins\n");
+			break;
+		case USB4_MARGIN_CAP_TIME_INDP_GEN_2_3_LR:
+			seq_puts(s, "# returns left or right margin\n");
+			break;
+		case USB4_MARGIN_CAP_TIME_INDP_GEN_2_3_BOTH:
+			seq_puts(s, "# returns both left and right margins\n");
+			break;
+		case USB4_MARGIN_CAP_TIME_INDP_GEN_4_MIN:
+			seq_puts(s, "# returns minimum between left and right time margins in both lower and upper eye\n");
+			break;
+		case USB4_MARGIN_CAP_TIME_INDP_GEN_4_BOTH:
+			seq_puts(s, "# returns both left and right margins of both upper and lower eye\n");
+			break;
+		case USB4_MARGIN_CAP_TIME_INDP_UNKNOWN:
+			tb_port_warn(margining->port,
+				     "failed to parse independent time margining capabilities\n");
+			ret = -EIO;
+			goto out;
+		}
+
+		seq_printf(s, "# time margin steps: %u\n",
+			   margining->time_steps);
+		seq_printf(s, "# maximum time offset: %u mUI\n",
+			   margining->max_time_offset);
+	} else {
+		seq_puts(s, "# time margining: no\n");
+	}
+
+out:
+	mutex_unlock(&tb->lock);
+	return ret;
+}
+DEBUGFS_ATTR_RO(margining_caps);
+
+static const struct {
+	enum usb4_margining_lane lane;
+	const char *name;
+} lane_names[] = {
+	{
+		.lane = USB4_MARGINING_LANE_RX0,
+		.name = "0",
+	},
+	{
+		.lane = USB4_MARGINING_LANE_RX1,
+		.name = "1",
+	},
+	{
+		.lane = USB4_MARGINING_LANE_RX2,
+		.name = "2",
+	},
+	{
+		.lane = USB4_MARGINING_LANE_ALL,
+		.name = "all",
+	},
+};
+
+static ssize_t
+margining_lanes_write(struct file *file, const char __user *user_buf,
+		      size_t count, loff_t *ppos)
+{
+	struct seq_file *s = file->private_data;
+	struct tb_margining *margining = s->private;
+	struct tb_port *port = margining->port;
+	struct tb *tb = port->sw->tb;
+	int lane = -1;
+	char *buf;
+
+	buf = validate_and_copy_from_user(user_buf, &count);
+	if (IS_ERR(buf))
+		return PTR_ERR(buf);
+
+	buf[count - 1] = '\0';
+
+	for (int i = 0; i < ARRAY_SIZE(lane_names); i++) {
+		if (!strcmp(buf, lane_names[i].name)) {
+			lane = lane_names[i].lane;
+			break;
+		}
+	}
+
+	kfree(buf);
+
+	if (lane == -1)
+		return -EINVAL;
+
+	scoped_cond_guard(mutex_intr, return -ERESTARTSYS, &tb->lock) {
+		if (lane == USB4_MARGINING_LANE_ALL && !all_lanes(margining))
+			return -EINVAL;
+		/*
+		 * Enabling on RX2 requires that it is supported by the
+		 * USB4 port.
+		 */
+		if (lane == USB4_MARGINING_LANE_RX2 && !margining->asym_rx)
+			return -EINVAL;
+
+		margining->lanes = lane;
+	}
+
+	return count;
+}
+
+static int margining_lanes_show(struct seq_file *s, void *not_used)
+{
+	struct tb_margining *margining = s->private;
+	struct tb_port *port = margining->port;
+	struct tb *tb = port->sw->tb;
+
+	scoped_cond_guard(mutex_intr, return -ERESTARTSYS, &tb->lock) {
+		for (int i = 0; i < ARRAY_SIZE(lane_names); i++) {
+			if (lane_names[i].lane == USB4_MARGINING_LANE_ALL &&
+			    !all_lanes(margining))
+				continue;
+			if (lane_names[i].lane == USB4_MARGINING_LANE_RX2 &&
+			    !margining->asym_rx)
+				continue;
+
+			if (i != 0)
+				seq_putc(s, ' ');
+
+			if (lane_names[i].lane == margining->lanes)
+				seq_printf(s, "[%s]", lane_names[i].name);
+			else
+				seq_printf(s, "%s", lane_names[i].name);
+		}
+		seq_puts(s, "\n");
+	}
+
+	return 0;
+}
+DEBUGFS_ATTR_RW(margining_lanes);
+
+static ssize_t
+margining_voltage_time_offset_write(struct file *file,
+				    const char __user *user_buf,
+				    size_t count, loff_t *ppos)
+{
+	struct seq_file *s = file->private_data;
+	struct tb_margining *margining = s->private;
+	struct tb *tb = margining->port->sw->tb;
+	unsigned int max_margin;
+	unsigned int val;
+	int ret;
+
+	ret = kstrtouint_from_user(user_buf, count, 10, &val);
+	if (ret)
+		return ret;
+
+	scoped_cond_guard(mutex_intr, return -ERESTARTSYS, &tb->lock) {
+		if (!margining->software)
+			return -EOPNOTSUPP;
+
+		if (margining->time)
+			max_margin = margining->time_steps;
+		else
+			if (margining->optional_voltage_offset_range)
+				max_margin = margining->voltage_steps_optional_range;
+			else
+				max_margin = margining->voltage_steps;
+
+		margining->voltage_time_offset = clamp(val, 0, max_margin);
+	}
+
+	return count;
+}
+
+static int margining_voltage_time_offset_show(struct seq_file *s,
+					      void *not_used)
+{
+	const struct tb_margining *margining = s->private;
+	struct tb *tb = margining->port->sw->tb;
+
+	scoped_cond_guard(mutex_intr, return -ERESTARTSYS, &tb->lock) {
+		if (!margining->software)
+			return -EOPNOTSUPP;
+
+		seq_printf(s, "%d\n", margining->voltage_time_offset);
+	}
+
+	return 0;
+}
+DEBUGFS_ATTR_RW(margining_voltage_time_offset);
+
+static ssize_t
+margining_error_counter_write(struct file *file, const char __user *user_buf,
+			      size_t count, loff_t *ppos)
+{
+	enum usb4_margin_sw_error_counter error_counter;
+	struct seq_file *s = file->private_data;
+	struct tb_margining *margining = s->private;
+	struct tb *tb = margining->port->sw->tb;
+	char *buf;
+
+	buf = validate_and_copy_from_user(user_buf, &count);
+	if (IS_ERR(buf))
+		return PTR_ERR(buf);
+
+	buf[count - 1] = '\0';
+
+	if (!strcmp(buf, "nop"))
+		error_counter = USB4_MARGIN_SW_ERROR_COUNTER_NOP;
+	else if (!strcmp(buf, "clear"))
+		error_counter = USB4_MARGIN_SW_ERROR_COUNTER_CLEAR;
+	else if (!strcmp(buf, "start"))
+		error_counter = USB4_MARGIN_SW_ERROR_COUNTER_START;
+	else if (!strcmp(buf, "stop"))
+		error_counter = USB4_MARGIN_SW_ERROR_COUNTER_STOP;
+	else
+		goto err_free;
+
+	kfree(buf);
+
+	scoped_cond_guard(mutex_intr, return -ERESTARTSYS, &tb->lock) {
+		if (!margining->software)
+			return -EOPNOTSUPP;
+
+		margining->error_counter = error_counter;
+	}
+
+	return count;
+
+err_free:
+	kfree(buf);
+	return -EINVAL;
+}
+
+static int margining_error_counter_show(struct seq_file *s, void *not_used)
+{
+	const struct tb_margining *margining = s->private;
+	struct tb *tb = margining->port->sw->tb;
+
+	scoped_cond_guard(mutex_intr, return -ERESTARTSYS, &tb->lock) {
+		if (!margining->software)
+			return -EOPNOTSUPP;
+
+		switch (margining->error_counter) {
+		case USB4_MARGIN_SW_ERROR_COUNTER_NOP:
+			seq_puts(s, "[nop] clear start stop\n");
+			break;
+		case USB4_MARGIN_SW_ERROR_COUNTER_CLEAR:
+			seq_puts(s, "nop [clear] start stop\n");
+			break;
+		case USB4_MARGIN_SW_ERROR_COUNTER_START:
+			seq_puts(s, "nop clear [start] stop\n");
+			break;
+		case USB4_MARGIN_SW_ERROR_COUNTER_STOP:
+			seq_puts(s, "nop clear start [stop]\n");
+			break;
+		}
+	}
+
+	return 0;
+}
+DEBUGFS_ATTR_RW(margining_error_counter);
+
+static ssize_t
+margining_dwell_time_write(struct file *file, const char __user *user_buf,
+			   size_t count, loff_t *ppos)
+{
+	struct seq_file *s = file->private_data;
+	struct tb_margining *margining = s->private;
+	struct tb *tb = margining->port->sw->tb;
+	unsigned int val;
+	int ret;
+
+	ret = kstrtouint_from_user(user_buf, count, 10, &val);
+	if (ret)
+		return ret;
+
+	scoped_cond_guard(mutex_intr, return -ERESTARTSYS, &tb->lock) {
+		if (!margining->software)
+			return -EOPNOTSUPP;
+
+		margining->dwell_time = clamp(val, MIN_DWELL_TIME, MAX_DWELL_TIME);
+	}
+
+	return count;
+}
+
+static int margining_dwell_time_show(struct seq_file *s, void *not_used)
+{
+	struct tb_margining *margining = s->private;
+	struct tb *tb = margining->port->sw->tb;
+
+	scoped_cond_guard(mutex_intr, return -ERESTARTSYS, &tb->lock) {
+		if (!margining->software)
+			return -EOPNOTSUPP;
+
+		seq_printf(s, "%d\n", margining->dwell_time);
+	}
+
+	return 0;
+}
+DEBUGFS_ATTR_RW(margining_dwell_time);
+
+static ssize_t
+margining_optional_voltage_offset_write(struct file *file, const char __user *user_buf,
+					size_t count, loff_t *ppos)
+{
+	struct seq_file *s = file->private_data;
+	struct tb_margining *margining = s->private;
+	struct tb *tb = margining->port->sw->tb;
+	bool val;
+	int ret;
+
+	ret = kstrtobool_from_user(user_buf, count, &val);
+	if (ret)
+		return ret;
+
+	scoped_cond_guard(mutex_intr, return -ERESTARTSYS, &tb->lock) {
+		margining->optional_voltage_offset_range = val;
+	}
+
+	return count;
+}
+
+static int margining_optional_voltage_offset_show(struct seq_file *s,
+						  void *not_used)
+{
+	struct tb_margining *margining = s->private;
+	struct tb *tb = margining->port->sw->tb;
+
+	scoped_cond_guard(mutex_intr, return -ERESTARTSYS, &tb->lock) {
+		seq_printf(s, "%u\n", margining->optional_voltage_offset_range);
+	}
+
+	return 0;
+}
+DEBUGFS_ATTR_RW(margining_optional_voltage_offset);
+
+static ssize_t margining_mode_write(struct file *file,
+				   const char __user *user_buf,
+				   size_t count, loff_t *ppos)
+{
+	struct seq_file *s = file->private_data;
+	struct tb_margining *margining = s->private;
+	struct tb *tb = margining->port->sw->tb;
+	int ret = 0;
+	char *buf;
+
+	buf = validate_and_copy_from_user(user_buf, &count);
+	if (IS_ERR(buf))
+		return PTR_ERR(buf);
+
+	buf[count - 1] = '\0';
+
+	if (mutex_lock_interruptible(&tb->lock)) {
+		ret = -ERESTARTSYS;
+		goto out_free;
+	}
+
+	if (!strcmp(buf, "software")) {
+		if (supports_software(margining))
+			margining->software = true;
+		else
+			ret = -EINVAL;
+	} else if (!strcmp(buf, "hardware")) {
+		if (supports_hardware(margining))
+			margining->software = false;
+		else
+			ret = -EINVAL;
+	} else {
+		ret = -EINVAL;
+	}
+
+	mutex_unlock(&tb->lock);
+
+out_free:
+	kfree(buf);
+	return ret ? ret : count;
+}
+
+static int margining_mode_show(struct seq_file *s, void *not_used)
+{
+	struct tb_margining *margining = s->private;
+	struct tb *tb = margining->port->sw->tb;
+	const char *space = "";
+
+	if (mutex_lock_interruptible(&tb->lock))
+		return -ERESTARTSYS;
+
+	if (supports_software(margining)) {
+		if (margining->software)
+			seq_puts(s, "[software]");
+		else
+			seq_puts(s, "software");
+		space = " ";
+	}
+	if (supports_hardware(margining)) {
+		if (margining->software)
+			seq_printf(s, "%shardware", space);
+		else
+			seq_printf(s, "%s[hardware]", space);
+	}
+
+	mutex_unlock(&tb->lock);
+
+	seq_puts(s, "\n");
+	return 0;
+}
+DEBUGFS_ATTR_RW(margining_mode);
+
+static int margining_run_sw(struct tb_margining *margining,
+			    struct usb4_port_margining_params *params)
+{
+	u32 nsamples = margining->dwell_time / DWELL_SAMPLE_INTERVAL;
+	int ret, i;
+
+	ret = usb4_port_sw_margin(margining->port, margining->target, margining->index,
+				  params, margining->results);
+	if (ret)
+		goto out_stop;
+
+	for (i = 0; i <= nsamples; i++) {
+		u32 errors = 0;
+
+		ret = usb4_port_sw_margin_errors(margining->port, margining->target,
+						 margining->index, &margining->results[1]);
+		if (ret)
+			break;
+
+		if (margining->lanes == USB4_MARGINING_LANE_RX0)
+			errors = FIELD_GET(USB4_MARGIN_SW_ERR_COUNTER_LANE_0_MASK,
+					   margining->results[1]);
+		else if (margining->lanes == USB4_MARGINING_LANE_RX1)
+			errors = FIELD_GET(USB4_MARGIN_SW_ERR_COUNTER_LANE_1_MASK,
+					   margining->results[1]);
+		else if (margining->lanes == USB4_MARGINING_LANE_RX2)
+			errors = FIELD_GET(USB4_MARGIN_SW_ERR_COUNTER_LANE_2_MASK,
+					   margining->results[1]);
+		else if (margining->lanes == USB4_MARGINING_LANE_ALL)
+			errors = margining->results[1];
+
+		/* Any errors stop the test */
+		if (errors)
+			break;
+
+		fsleep(DWELL_SAMPLE_INTERVAL * USEC_PER_MSEC);
+	}
+
+out_stop:
+	/*
+	 * Stop the counters but don't clear them to allow the
+	 * different error counter configurations.
+	 */
+	margining_modify_error_counter(margining, margining->lanes,
+				       USB4_MARGIN_SW_ERROR_COUNTER_STOP);
+	return ret;
+}
+
+static int validate_margining(struct tb_margining *margining)
+{
+	/*
+	 * For running on RX2 the link must be asymmetric with 3
+	 * receivers. Because this can change dynamically, check it
+	 * here before we start the margining and report back error if
+	 * expectations are not met.
+	 */
+	if (margining->lanes == USB4_MARGINING_LANE_RX2) {
+		int ret;
+
+		ret = tb_port_get_link_width(margining->port);
+		if (ret < 0)
+			return ret;
+		if (ret != TB_LINK_WIDTH_ASYM_RX) {
+			tb_port_warn(margining->port, "link is %s expected %s",
+				     tb_width_name(ret),
+				     tb_width_name(TB_LINK_WIDTH_ASYM_RX));
+			return -EINVAL;
+		}
+	}
+
+	return 0;
+}
+
+static int margining_run_write(void *data, u64 val)
+{
+	struct tb_margining *margining = data;
+	struct tb_port *port = margining->port;
+	struct device *dev = margining->dev;
+	struct tb_switch *sw = port->sw;
+	struct tb_switch *down_sw;
+	struct tb *tb = sw->tb;
+	int ret, clx;
+
+	if (val != 1)
+		return -EINVAL;
+
+	pm_runtime_get_sync(dev);
+
+	if (mutex_lock_interruptible(&tb->lock)) {
+		ret = -ERESTARTSYS;
+		goto out_rpm_put;
+	}
+
+	ret = validate_margining(margining);
+	if (ret)
+		goto out_unlock;
+
+	if (tb_is_upstream_port(port))
+		down_sw = sw;
+	else if (port->remote)
+		down_sw = port->remote->sw;
+	else
+		down_sw = NULL;
+
+	if (down_sw) {
+		/*
+		 * CL states may interfere with lane margining so
+		 * disable them temporarily now.
+		 */
+		ret = tb_switch_clx_disable(down_sw);
+		if (ret < 0) {
+			tb_sw_warn(down_sw, "failed to disable CL states\n");
+			goto out_unlock;
+		}
+		clx = ret;
+	}
+
+	/* Clear the results */
+	memset(margining->results, 0, sizeof(margining->results));
+
+	if (margining->software) {
+		struct usb4_port_margining_params params = {
+			.error_counter = USB4_MARGIN_SW_ERROR_COUNTER_CLEAR,
+			.lanes = margining->lanes,
+			.time = margining->time,
+			.voltage_time_offset = margining->voltage_time_offset,
+			.right_high = margining->right_high,
+			.upper_eye = margining->upper_eye,
+			.optional_voltage_offset_range = margining->optional_voltage_offset_range,
+		};
+
+		tb_port_dbg(port,
+			    "running software %s lane margining for %s lanes %u\n",
+			    margining->time ? "time" : "voltage", dev_name(dev),
+			    margining->lanes);
+
+		ret = margining_run_sw(margining, &params);
+	} else {
+		struct usb4_port_margining_params params = {
+			.ber_level = margining->ber_level,
+			.lanes = margining->lanes,
+			.time = margining->time,
+			.right_high = margining->right_high,
+			.upper_eye = margining->upper_eye,
+			.optional_voltage_offset_range = margining->optional_voltage_offset_range,
+		};
+
+		tb_port_dbg(port,
+			    "running hardware %s lane margining for %s lanes %u\n",
+			    margining->time ? "time" : "voltage", dev_name(dev),
+			    margining->lanes);
+
+		ret = usb4_port_hw_margin(port, margining->target, margining->index, &params,
+					  margining->results, ARRAY_SIZE(margining->results));
+	}
+
+	if (down_sw)
+		tb_switch_clx_enable(down_sw, clx);
+out_unlock:
+	mutex_unlock(&tb->lock);
+out_rpm_put:
+	pm_runtime_mark_last_busy(dev);
+	pm_runtime_put_autosuspend(dev);
+
+	return ret;
+}
+DEFINE_DEBUGFS_ATTRIBUTE(margining_run_fops, NULL, margining_run_write,
+			 "%llu\n");
+
+static ssize_t margining_results_write(struct file *file,
+				       const char __user *user_buf,
+				       size_t count, loff_t *ppos)
+{
+	struct seq_file *s = file->private_data;
+	struct tb_margining *margining = s->private;
+	struct tb *tb = margining->port->sw->tb;
+
+	if (mutex_lock_interruptible(&tb->lock))
+		return -ERESTARTSYS;
+
+	/* Just clear the results */
+	memset(margining->results, 0, sizeof(margining->results));
+
+	if (margining->software) {
+		/* Clear the error counters */
+		margining_modify_error_counter(margining,
+					       USB4_MARGINING_LANE_ALL,
+					       USB4_MARGIN_SW_ERROR_COUNTER_CLEAR);
+	}
+
+	mutex_unlock(&tb->lock);
+	return count;
+}
+
+static void voltage_margin_show(struct seq_file *s,
+				const struct tb_margining *margining, u8 val)
+{
+	unsigned int tmp, voltage;
+
+	tmp = FIELD_GET(USB4_MARGIN_HW_RES_MARGIN_MASK, val);
+	voltage = tmp * margining->max_voltage_offset / margining->voltage_steps;
+	seq_printf(s, "%u mV (%u)", voltage, tmp);
+	if (val & USB4_MARGIN_HW_RES_EXCEEDS)
+		seq_puts(s, " exceeds maximum");
+	seq_puts(s, "\n");
+	if (margining->optional_voltage_offset_range)
+		seq_puts(s, " optional voltage offset range enabled\n");
+}
+
+static void time_margin_show(struct seq_file *s,
+			     const struct tb_margining *margining, u8 val)
+{
+	unsigned int tmp, interval;
+
+	tmp = FIELD_GET(USB4_MARGIN_HW_RES_MARGIN_MASK, val);
+	interval = tmp * margining->max_time_offset / margining->time_steps;
+	seq_printf(s, "%u mUI (%u)", interval, tmp);
+	if (val & USB4_MARGIN_HW_RES_EXCEEDS)
+		seq_puts(s, " exceeds maximum");
+	seq_puts(s, "\n");
+}
+
+static u8 margining_hw_result_val(const u32 *results,
+				  enum usb4_margining_lane lane,
+				  bool right_high)
+{
+	u32 val;
+
+	if (lane == USB4_MARGINING_LANE_RX0)
+		val = results[1];
+	else if (lane == USB4_MARGINING_LANE_RX1)
+		val = results[1] >> USB4_MARGIN_HW_RES_LANE_SHIFT;
+	else if (lane == USB4_MARGINING_LANE_RX2)
+		val = results[2];
+	else
+		val = 0;
+
+	return right_high ? val : val >> USB4_MARGIN_HW_RES_LL_SHIFT;
+}
+
+static void margining_hw_result_format(struct seq_file *s,
+				       const struct tb_margining *margining,
+				       enum usb4_margining_lane lane)
+{
+	u8 val;
+
+	if (margining->time) {
+		val = margining_hw_result_val(margining->results, lane, true);
+		seq_printf(s, "# lane %u right time margin: ", lane);
+		time_margin_show(s, margining, val);
+		val = margining_hw_result_val(margining->results, lane, false);
+		seq_printf(s, "# lane %u left time margin: ", lane);
+		time_margin_show(s, margining, val);
+	} else {
+		val = margining_hw_result_val(margining->results, lane, true);
+		seq_printf(s, "# lane %u high voltage margin: ", lane);
+		voltage_margin_show(s, margining, val);
+		val = margining_hw_result_val(margining->results, lane, false);
+		seq_printf(s, "# lane %u low voltage margin: ", lane);
+		voltage_margin_show(s, margining, val);
+	}
+}
+
+static int margining_results_show(struct seq_file *s, void *not_used)
+{
+	struct tb_margining *margining = s->private;
+	struct tb *tb = margining->port->sw->tb;
+
+	if (mutex_lock_interruptible(&tb->lock))
+		return -ERESTARTSYS;
+
+	/* Dump the raw results first */
+	seq_printf(s, "0x%08x\n", margining->results[0]);
+	/* Only the hardware margining has two result dwords */
+	if (!margining->software) {
+		for (int i = 1; i < ARRAY_SIZE(margining->results); i++)
+			seq_printf(s, "0x%08x\n", margining->results[i]);
+
+		if (margining->lanes == USB4_MARGINING_LANE_ALL) {
+			margining_hw_result_format(s, margining,
+						   USB4_MARGINING_LANE_RX0);
+			margining_hw_result_format(s, margining,
+						   USB4_MARGINING_LANE_RX1);
+			if (margining->asym_rx)
+				margining_hw_result_format(s, margining,
+						USB4_MARGINING_LANE_RX2);
+		} else {
+			margining_hw_result_format(s, margining,
+						   margining->lanes);
+		}
+	} else {
+		u32 lane_errors, result;
+
+		seq_printf(s, "0x%08x\n", margining->results[1]);
+
+		result = FIELD_GET(USB4_MARGIN_SW_LANES_MASK, margining->results[0]);
+		if (result == USB4_MARGINING_LANE_RX0 ||
+		    result == USB4_MARGINING_LANE_ALL) {
+			lane_errors = FIELD_GET(USB4_MARGIN_SW_ERR_COUNTER_LANE_0_MASK,
+						margining->results[1]);
+			seq_printf(s, "# lane 0 errors: %u\n", lane_errors);
+		}
+		if (result == USB4_MARGINING_LANE_RX1 ||
+		    result == USB4_MARGINING_LANE_ALL) {
+			lane_errors = FIELD_GET(USB4_MARGIN_SW_ERR_COUNTER_LANE_1_MASK,
+						margining->results[1]);
+			seq_printf(s, "# lane 1 errors: %u\n", lane_errors);
+		}
+		if (margining->asym_rx &&
+		    (result == USB4_MARGINING_LANE_RX2 ||
+		     result == USB4_MARGINING_LANE_ALL)) {
+			lane_errors = FIELD_GET(USB4_MARGIN_SW_ERR_COUNTER_LANE_2_MASK,
+						margining->results[1]);
+			seq_printf(s, "# lane 2 errors: %u\n", lane_errors);
+		}
+	}
+
+	mutex_unlock(&tb->lock);
+	return 0;
+}
+DEBUGFS_ATTR_RW(margining_results);
+
+static ssize_t margining_test_write(struct file *file,
+				    const char __user *user_buf,
+				    size_t count, loff_t *ppos)
+{
+	struct seq_file *s = file->private_data;
+	struct tb_margining *margining = s->private;
+	struct tb *tb = margining->port->sw->tb;
+	int ret = 0;
+	char *buf;
+
+	buf = validate_and_copy_from_user(user_buf, &count);
+	if (IS_ERR(buf))
+		return PTR_ERR(buf);
+
+	buf[count - 1] = '\0';
+
+	if (mutex_lock_interruptible(&tb->lock)) {
+		ret = -ERESTARTSYS;
+		goto out_free;
+	}
+
+	if (!strcmp(buf, "time") && supports_time(margining))
+		margining->time = true;
+	else if (!strcmp(buf, "voltage"))
+		margining->time = false;
+	else
+		ret = -EINVAL;
+
+	mutex_unlock(&tb->lock);
+
+out_free:
+	kfree(buf);
+	return ret ? ret : count;
+}
+
+static int margining_test_show(struct seq_file *s, void *not_used)
+{
+	struct tb_margining *margining = s->private;
+	struct tb *tb = margining->port->sw->tb;
+
+	if (mutex_lock_interruptible(&tb->lock))
+		return -ERESTARTSYS;
+
+	if (supports_time(margining)) {
+		if (margining->time)
+			seq_puts(s, "voltage [time]\n");
+		else
+			seq_puts(s, "[voltage] time\n");
+	} else {
+		seq_puts(s, "[voltage]\n");
+	}
+
+	mutex_unlock(&tb->lock);
+	return 0;
+}
+DEBUGFS_ATTR_RW(margining_test);
+
+static ssize_t margining_margin_write(struct file *file,
+				    const char __user *user_buf,
+				    size_t count, loff_t *ppos)
+{
+	struct seq_file *s = file->private_data;
+	struct tb_margining *margining = s->private;
+	struct tb *tb = margining->port->sw->tb;
+	int ret = 0;
+	char *buf;
+
+	buf = validate_and_copy_from_user(user_buf, &count);
+	if (IS_ERR(buf))
+		return PTR_ERR(buf);
+
+	buf[count - 1] = '\0';
+
+	if (mutex_lock_interruptible(&tb->lock)) {
+		ret = -ERESTARTSYS;
+		goto out_free;
+	}
+
+	if (margining->time) {
+		if (!strcmp(buf, "left"))
+			margining->right_high = false;
+		else if (!strcmp(buf, "right"))
+			margining->right_high = true;
+		else
+			ret = -EINVAL;
+	} else {
+		if (!strcmp(buf, "low"))
+			margining->right_high = false;
+		else if (!strcmp(buf, "high"))
+			margining->right_high = true;
+		else
+			ret = -EINVAL;
+	}
+
+	mutex_unlock(&tb->lock);
+
+out_free:
+	kfree(buf);
+	return ret ? ret : count;
+}
+
+static int margining_margin_show(struct seq_file *s, void *not_used)
+{
+	struct tb_margining *margining = s->private;
+	struct tb *tb = margining->port->sw->tb;
+
+	if (mutex_lock_interruptible(&tb->lock))
+		return -ERESTARTSYS;
+
+	if (margining->time) {
+		if (margining->right_high)
+			seq_puts(s, "left [right]\n");
+		else
+			seq_puts(s, "[left] right\n");
+	} else {
+		if (margining->right_high)
+			seq_puts(s, "low [high]\n");
+		else
+			seq_puts(s, "[low] high\n");
+	}
+
+	mutex_unlock(&tb->lock);
+	return 0;
+}
+DEBUGFS_ATTR_RW(margining_margin);
+
+static ssize_t margining_eye_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 usb4_port *usb4 = port->usb4;
+	struct tb *tb = port->sw->tb;
+	int ret = 0;
+	char *buf;
+
+	buf = validate_and_copy_from_user(user_buf, &count);
+	if (IS_ERR(buf))
+		return PTR_ERR(buf);
+
+	buf[count - 1] = '\0';
+
+	scoped_cond_guard(mutex_intr, ret = -ERESTARTSYS, &tb->lock) {
+		if (!strcmp(buf, "lower"))
+			usb4->margining->upper_eye = false;
+		else if (!strcmp(buf, "upper"))
+			usb4->margining->upper_eye = true;
+		else
+			ret = -EINVAL;
+	}
+
+	kfree(buf);
+	return ret ? ret : count;
+}
+
+static int margining_eye_show(struct seq_file *s, void *not_used)
+{
+	struct tb_port *port = s->private;
+	struct usb4_port *usb4 = port->usb4;
+	struct tb *tb = port->sw->tb;
+
+	scoped_guard(mutex_intr, &tb->lock) {
+		if (usb4->margining->upper_eye)
+			seq_puts(s, "lower [upper]\n");
+		else
+			seq_puts(s, "[lower] upper\n");
+
+		return 0;
+	}
+
+	return -ERESTARTSYS;
+}
+DEBUGFS_ATTR_RW(margining_eye);
+
+static struct tb_margining *margining_alloc(struct tb_port *port,
+					    struct device *dev,
+					    enum usb4_sb_target target,
+					    u8 index, struct dentry *parent)
+{
+	struct tb_margining *margining;
+	struct dentry *dir;
+	unsigned int val;
+	int ret;
+
+	ret = tb_port_get_link_generation(port);
+	if (ret < 0) {
+		tb_port_warn(port, "failed to read link generation\n");
+		return NULL;
+	}
+
+	margining = kzalloc_obj(*margining);
+	if (!margining)
+		return NULL;
+
+	margining->port = port;
+	margining->target = target;
+	margining->index = index;
+	margining->dev = dev;
+	margining->gen = ret;
+	margining->asym_rx = tb_port_width_supported(port, TB_LINK_WIDTH_ASYM_RX);
+
+	ret = usb4_port_margining_caps(port, target, index, margining->caps,
+				       ARRAY_SIZE(margining->caps));
+	if (ret) {
+		kfree(margining);
+		return NULL;
+	}
+
+	/* Set the initial mode */
+	if (supports_software(margining))
+		margining->software = true;
+
+	if (margining->gen < 4) {
+		val = FIELD_GET(USB4_MARGIN_CAP_0_VOLTAGE_STEPS_MASK, margining->caps[0]);
+		margining->voltage_steps = val;
+		val = FIELD_GET(USB4_MARGIN_CAP_0_MAX_VOLTAGE_OFFSET_MASK, margining->caps[0]);
+		margining->max_voltage_offset = 74 + val * 2;
+	} else {
+		val = FIELD_GET(USB4_MARGIN_CAP_2_VOLTAGE_STEPS_MASK, margining->caps[2]);
+		margining->voltage_steps = val;
+		val = FIELD_GET(USB4_MARGIN_CAP_2_MAX_VOLTAGE_OFFSET_MASK, margining->caps[2]);
+		margining->max_voltage_offset = 74 + val * 2;
+	}
+
+	if (supports_optional_voltage_offset_range(margining)) {
+		val = FIELD_GET(USB4_MARGIN_CAP_0_VOLT_STEPS_OPT_MASK,
+				margining->caps[0]);
+		margining->voltage_steps_optional_range = val;
+		val = FIELD_GET(USB4_MARGIN_CAP_1_MAX_VOLT_OFS_OPT_MASK,
+				margining->caps[1]);
+		margining->max_voltage_offset_optional_range = 74 + val * 2;
+	}
+
+	if (supports_time(margining)) {
+		val = FIELD_GET(USB4_MARGIN_CAP_1_TIME_STEPS_MASK, margining->caps[1]);
+		margining->time_steps = val;
+		val = FIELD_GET(USB4_MARGIN_CAP_1_TIME_OFFSET_MASK, margining->caps[1]);
+		/*
+		 * Store it as mUI (milli Unit Interval) because we want
+		 * to keep it as integer.
+		 */
+		margining->max_time_offset = 200 + 10 * val;
+	}
+
+	dir = debugfs_create_dir("margining", parent);
+	if (supports_hardware(margining)) {
+		val = FIELD_GET(USB4_MARGIN_CAP_1_MIN_BER_MASK, margining->caps[1]);
+		margining->min_ber_level = val;
+		val = FIELD_GET(USB4_MARGIN_CAP_1_MAX_BER_MASK, margining->caps[1]);
+		margining->max_ber_level = val;
+
+		/* Set the default to minimum */
+		margining->ber_level = margining->min_ber_level;
+
+		debugfs_create_file("ber_level_contour", 0400, dir, margining,
+				    &margining_ber_level_fops);
+	}
+	debugfs_create_file("caps", 0400, dir, margining, &margining_caps_fops);
+	debugfs_create_file("lanes", 0600, dir, margining, &margining_lanes_fops);
+	debugfs_create_file("mode", 0600, dir, margining, &margining_mode_fops);
+	debugfs_create_file("run", 0600, dir, margining, &margining_run_fops);
+	debugfs_create_file("results", 0600, dir, margining,
+			    &margining_results_fops);
+	debugfs_create_file("test", 0600, dir, margining, &margining_test_fops);
+	if (independent_voltage_margins(margining) == USB4_MARGIN_CAP_VOLTAGE_INDP_GEN_2_3_HL ||
+	    (supports_time(margining) &&
+	     independent_time_margins(margining) == USB4_MARGIN_CAP_TIME_INDP_GEN_2_3_LR))
+		debugfs_create_file("margin", 0600, dir, margining, &margining_margin_fops);
+
+	margining->error_counter = USB4_MARGIN_SW_ERROR_COUNTER_CLEAR;
+	margining->dwell_time = MIN_DWELL_TIME;
+
+	if (supports_optional_voltage_offset_range(margining))
+		debugfs_create_file("optional_voltage_offset", DEBUGFS_MODE, dir, margining,
+				    &margining_optional_voltage_offset_fops);
+
+	if (supports_software(margining)) {
+		debugfs_create_file("voltage_time_offset", DEBUGFS_MODE, dir, margining,
+				    &margining_voltage_time_offset_fops);
+		debugfs_create_file("error_counter", DEBUGFS_MODE, dir, margining,
+				    &margining_error_counter_fops);
+		debugfs_create_file("dwell_time", DEBUGFS_MODE, dir, margining,
+				    &margining_dwell_time_fops);
+	}
+
+	if (margining->gen >= 4)
+		debugfs_create_file("eye", 0600, dir, port, &margining_eye_fops);
+
+	return margining;
+}
+
+static void margining_port_init(struct tb_port *port)
+{
+	struct dentry *parent;
+	char dir_name[10];
+
+	if (!port->usb4)
+		return;
+
+	snprintf(dir_name, sizeof(dir_name), "port%d", port->port);
+	parent = debugfs_lookup(dir_name, port->sw->debugfs_dir);
+	port->usb4->margining = margining_alloc(port, &port->usb4->dev,
+						USB4_SB_TARGET_ROUTER, 0,
+						parent);
+}
+
+static void margining_port_remove(struct tb_port *port)
+{
+	struct dentry *parent;
+	char dir_name[10];
+
+	if (!port->usb4)
+		return;
+	if (!port->usb4->margining)
+		return;
+
+	snprintf(dir_name, sizeof(dir_name), "port%d", port->port);
+	parent = debugfs_lookup(dir_name, port->sw->debugfs_dir);
+	if (parent)
+		debugfs_lookup_and_remove("margining", parent);
+
+	kfree(port->usb4->margining);
+	port->usb4->margining = NULL;
+}
+
+static void margining_switch_init(struct tb_switch *sw)
+{
+	struct tb_port *upstream, *downstream;
+	struct tb_switch *parent_sw;
+	u64 route = tb_route(sw);
+
+	if (!route)
+		return;
+
+	upstream = tb_upstream_port(sw);
+	parent_sw = tb_switch_parent(sw);
+	downstream = tb_port_at(route, parent_sw);
+
+	margining_port_init(downstream);
+	margining_port_init(upstream);
+}
+
+static void margining_switch_remove(struct tb_switch *sw)
+{
+	struct tb_port *upstream, *downstream;
+	struct tb_switch *parent_sw;
+	u64 route = tb_route(sw);
+
+	if (!route)
+		return;
+
+	upstream = tb_upstream_port(sw);
+	parent_sw = tb_switch_parent(sw);
+	downstream = tb_port_at(route, parent_sw);
+
+	margining_port_remove(upstream);
+	margining_port_remove(downstream);
+}
+
+static void margining_xdomain_init(struct tb_xdomain *xd)
+{
+	struct tb_switch *parent_sw;
+	struct tb_port *downstream;
+
+	parent_sw = tb_xdomain_parent(xd);
+	downstream = tb_port_at(xd->route, parent_sw);
+
+	margining_port_init(downstream);
+}
+
+static void margining_xdomain_remove(struct tb_xdomain *xd)
+{
+	struct tb_switch *parent_sw;
+	struct tb_port *downstream;
+
+	parent_sw = tb_xdomain_parent(xd);
+	downstream = tb_port_at(xd->route, parent_sw);
+	margining_port_remove(downstream);
+}
+
+static void margining_retimer_init(struct tb_retimer *rt, struct dentry *debugfs_dir)
+{
+	rt->margining = margining_alloc(rt->port, &rt->dev,
+					USB4_SB_TARGET_RETIMER, rt->index,
+					debugfs_dir);
+}
+
+static void margining_retimer_remove(struct tb_retimer *rt)
+{
+	kfree(rt->margining);
+	rt->margining = NULL;
+}
+#else
+static inline void margining_switch_init(struct tb_switch *sw) { }
+static inline void margining_switch_remove(struct tb_switch *sw) { }
+static inline void margining_xdomain_init(struct tb_xdomain *xd) { }
+static inline void margining_xdomain_remove(struct tb_xdomain *xd) { }
+static inline void margining_retimer_init(struct tb_retimer *rt,
+					  struct dentry *debugfs_dir) { }
+static inline void margining_retimer_remove(struct tb_retimer *rt) { }
+#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);
+	kfree(buf);
+
+	return ret < 0 ? ret : count;
+}
+
+static void cap_show_by_dw(struct seq_file *s, struct tb_switch *sw,
+			   struct tb_port *port, unsigned int cap,
+			   unsigned int offset, u8 cap_id, u8 vsec_id,
+			   int dwords)
+{
+	int i, ret;
+	u32 data;
+
+	for (i = 0; i < dwords; i++) {
+		if (port)
+			ret = tb_port_read(port, &data, TB_CFG_PORT, cap + offset + i, 1);
+		else
+			ret = tb_sw_read(sw, &data, TB_CFG_SWITCH, cap + offset + i, 1);
+		if (ret) {
+			seq_printf(s, "0x%04x <not accessible>\n", cap + offset + i);
+			continue;
+		}
+
+		seq_printf(s, "0x%04x %4d 0x%02x 0x%02x 0x%08x\n", cap + offset + i,
+			   offset + i, cap_id, vsec_id, data);
+	}
+}
+
+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) {
+			cap_show_by_dw(s, sw, port, cap, offset, cap_id, vsec_id, length);
+			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:
+		if (usb4_switch_version(port->sw) < 2)
+			length = PORT_CAP_TMU_V1_LEN;
+		else
+			length = PORT_CAP_TMU_V2_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)) {
+			if (usb4_switch_version(port->sw) < 2)
+				length = PORT_CAP_V1_PCIE_LEN;
+			else
+				length = PORT_CAP_V2_PCIE_LEN;
+		} else if (tb_port_is_dpin(port)) {
+			if (usb4_switch_version(port->sw) < 2)
+				length = PORT_CAP_DP_V1_LEN;
+			else
+				length = PORT_CAP_DP_V2_LEN;
+		} else if (tb_port_is_dpout(port)) {
+			length = PORT_CAP_DP_V1_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;
+		}
+		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;
+
+	port_caps_show(port, s);
+
+out_unlock:
+	mutex_unlock(&tb->lock);
+out_rpm_put:
+	pm_runtime_mark_last_busy(&sw->dev);
+	pm_runtime_put_autosuspend(&sw->dev);
+
+	return ret;
+}
+DEBUGFS_ATTR_RW(port_regs);
+
+static void switch_cap_show(struct tb_switch *sw, struct seq_file *s,
+			    unsigned int cap)
+{
+	struct tb_cap_any header;
+	int ret, length;
+	u8 vsec_id = 0;
+
+	ret = tb_sw_read(sw, &header, TB_CFG_SWITCH, cap, 1);
+	if (ret) {
+		seq_printf(s, "0x%04x <capability read failed>\n", cap);
+		return;
+	}
+
+	if (header.basic.cap == TB_SWITCH_CAP_VSE) {
+		if (!header.extended_short.length) {
+			ret = tb_sw_read(sw, (u32 *)&header + 1, TB_CFG_SWITCH,
+					 cap + 1, 1);
+			if (ret) {
+				seq_printf(s, "0x%04x <capability read failed>\n",
+					   cap + 1);
+				return;
+			}
+			length = header.extended_long.length;
+		} else {
+			length = header.extended_short.length;
+		}
+		vsec_id = header.extended_short.vsec_id;
+	} else {
+		if (header.basic.cap == TB_SWITCH_CAP_TMU) {
+			length = SWITCH_CAP_TMU_LEN;
+		} else  {
+			seq_printf(s, "0x%04x <unknown capability 0x%02x>\n",
+				   cap, header.basic.cap);
+			return;
+		}
+	}
+
+	cap_show(s, sw, NULL, cap, header.basic.cap, vsec_id, length);
+}
+
+static void switch_caps_show(struct tb_switch *sw, struct seq_file *s)
+{
+	int cap;
+
+	cap = tb_switch_next_cap(sw, 0);
+	while (cap > 0) {
+		switch_cap_show(sw, s, cap);
+		cap = tb_switch_next_cap(sw, cap);
+	}
+}
+
+static int switch_basic_regs_show(struct tb_switch *sw, struct seq_file *s)
+{
+	u32 data[SWITCH_CAP_BASIC_LEN];
+	size_t dwords;
+	int ret, i;
+
+	/* Only USB4 has the additional registers */
+	if (tb_switch_is_usb4(sw))
+		dwords = ARRAY_SIZE(data);
+	else
+		dwords = 5;
+
+	ret = tb_sw_read(sw, data, TB_CFG_SWITCH, 0, dwords);
+	if (ret)
+		return ret;
+
+	for (i = 0; i < dwords; i++)
+		seq_printf(s, "0x%04x %4d 0x00 0x00 0x%08x\n", i, i, data[i]);
+
+	return 0;
+}
+
+static int switch_regs_show(struct seq_file *s, void *not_used)
+{
+	struct tb_switch *sw = s->private;
+	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 = switch_basic_regs_show(sw, s);
+	if (ret)
+		goto out_unlock;
+
+	switch_caps_show(sw, s);
+
+out_unlock:
+	mutex_unlock(&tb->lock);
+out_rpm_put:
+	pm_runtime_mark_last_busy(&sw->dev);
+	pm_runtime_put_autosuspend(&sw->dev);
+
+	return ret;
+}
+DEBUGFS_ATTR_RW(switch_regs);
+
+static int path_show_one(struct tb_port *port, struct seq_file *s, int hopid)
+{
+	u32 data[PATH_LEN];
+	int ret, i;
+
+	ret = tb_port_read(port, data, TB_CFG_HOPS, hopid * PATH_LEN,
+			   ARRAY_SIZE(data));
+	if (ret) {
+		seq_printf(s, "0x%04x <not accessible>\n", hopid * PATH_LEN);
+		return ret;
+	}
+
+	for (i = 0; i < ARRAY_SIZE(data); i++) {
+		seq_printf(s, "0x%04x %4d 0x%02x 0x%08x\n",
+			   hopid * PATH_LEN + i, i, hopid, data[i]);
+	}
+
+	return 0;
+}
+
+static int path_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 start, i, ret = 0;
+
+	pm_runtime_get_sync(&sw->dev);
+
+	if (mutex_lock_interruptible(&tb->lock)) {
+		ret = -ERESTARTSYS;
+		goto out_rpm_put;
+	}
+
+	seq_puts(s, "# offset relative_offset in_hop_id value\n");
+
+	/* NHI and lane adapters have entry for path 0 */
+	if (tb_port_is_null(port) || tb_port_is_nhi(port)) {
+		ret = path_show_one(port, s, 0);
+		if (ret)
+			goto out_unlock;
+	}
+
+	start = tb_port_is_nhi(port) ? 1 : TB_PATH_MIN_HOPID;
+
+	for (i = start; i <= port->config.max_in_hop_id; i++) {
+		ret = path_show_one(port, s, i);
+		if (ret)
+			break;
+	}
+
+out_unlock:
+	mutex_unlock(&tb->lock);
+out_rpm_put:
+	pm_runtime_mark_last_busy(&sw->dev);
+	pm_runtime_put_autosuspend(&sw->dev);
+
+	return ret;
+}
+DEBUGFS_ATTR_RW(path);
+
+static int counter_set_regs_show(struct tb_port *port, struct seq_file *s,
+				 int counter)
+{
+	u32 data[COUNTER_SET_LEN];
+	int ret, i;
+
+	ret = tb_port_read(port, data, TB_CFG_COUNTERS,
+			   counter * COUNTER_SET_LEN, ARRAY_SIZE(data));
+	if (ret) {
+		seq_printf(s, "0x%04x <not accessible>\n",
+			   counter * COUNTER_SET_LEN);
+		return ret;
+	}
+
+	for (i = 0; i < ARRAY_SIZE(data); i++) {
+		seq_printf(s, "0x%04x %4d 0x%02x 0x%08x\n",
+			   counter * COUNTER_SET_LEN + i, i, counter, data[i]);
+	}
+
+	return 0;
+}
+
+static int counters_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 i, ret = 0;
+
+	pm_runtime_get_sync(&sw->dev);
+
+	if (mutex_lock_interruptible(&tb->lock)) {
+		ret = -ERESTARTSYS;
+		goto out;
+	}
+
+	seq_puts(s, "# offset relative_offset counter_id value\n");
+
+	for (i = 0; i < port->config.max_counters; i++) {
+		ret = counter_set_regs_show(port, s, i);
+		if (ret)
+			break;
+	}
+
+	mutex_unlock(&tb->lock);
+
+out:
+	pm_runtime_mark_last_busy(&sw->dev);
+	pm_runtime_put_autosuspend(&sw->dev);
+
+	return ret;
+}
+DEBUGFS_ATTR_RW(counters);
+
+static int sb_regs_show(struct tb_port *port, const struct sb_reg *sb_regs,
+			size_t size, enum usb4_sb_target target, u8 index,
+			struct seq_file *s)
+{
+	int ret, i;
+
+	seq_puts(s, "# register value\n");
+
+	for (i = 0; i < size; i++) {
+		const struct sb_reg *regs = &sb_regs[i];
+		u8 data[64];
+		int j;
+
+		memset(data, 0, sizeof(data));
+		ret = usb4_port_sb_read(port, target, index, regs->reg, data,
+					regs->size);
+		if (ret) {
+			seq_printf(s, "0x%02x <not accessible>\n", regs->reg);
+			continue;
+		}
+
+		seq_printf(s, "0x%02x", regs->reg);
+		for (j = 0; j < regs->size; j++)
+			seq_printf(s, " 0x%02x", data[j]);
+		seq_puts(s, "\n");
+	}
+
+	return 0;
+}
+
+static int port_sb_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;
+	}
+
+	ret = sb_regs_show(port, port_sb_regs, ARRAY_SIZE(port_sb_regs),
+			   USB4_SB_TARGET_ROUTER, 0, s);
+
+	mutex_unlock(&tb->lock);
+out_rpm_put:
+	pm_runtime_mark_last_busy(&sw->dev);
+	pm_runtime_put_autosuspend(&sw->dev);
+
+	return ret;
+}
+DEBUGFS_ATTR_RW(port_sb_regs);
+
+/**
+ * tb_switch_debugfs_init() - Add debugfs entries for router
+ * @sw: Pointer to the router
+ *
+ * Adds debugfs directories and files for given router.
+ */
+void tb_switch_debugfs_init(struct tb_switch *sw)
+{
+	struct dentry *debugfs_dir;
+	struct tb_port *port;
+
+	debugfs_dir = debugfs_create_dir(dev_name(&sw->dev), tb_debugfs_root);
+	sw->debugfs_dir = debugfs_dir;
+	debugfs_create_file("regs", DEBUGFS_MODE, debugfs_dir, sw,
+			    &switch_regs_fops);
+	if (sw->drom)
+		debugfs_create_blob("drom", 0400, debugfs_dir, &sw->drom_blob);
+
+	tb_switch_for_each_port(sw, port) {
+		struct dentry *debugfs_dir;
+		char dir_name[10];
+
+		if (port->disabled)
+			continue;
+		if (port->config.type == TB_TYPE_INACTIVE)
+			continue;
+
+		snprintf(dir_name, sizeof(dir_name), "port%d", port->port);
+		debugfs_dir = debugfs_create_dir(dir_name, sw->debugfs_dir);
+		debugfs_create_file("regs", DEBUGFS_MODE, debugfs_dir,
+				    port, &port_regs_fops);
+		debugfs_create_file("path", 0400, debugfs_dir, port,
+				    &path_fops);
+		if (port->config.counters_support)
+			debugfs_create_file("counters", 0600, debugfs_dir, port,
+					    &counters_fops);
+		if (port->usb4)
+			debugfs_create_file("sb_regs", DEBUGFS_MODE, debugfs_dir,
+					    port, &port_sb_regs_fops);
+	}
+
+	margining_switch_init(sw);
+}
+
+/**
+ * tb_switch_debugfs_remove() - Remove all router debugfs entries
+ * @sw: Pointer to the router
+ *
+ * Removes all previously added debugfs entries under this router.
+ */
+void tb_switch_debugfs_remove(struct tb_switch *sw)
+{
+	margining_switch_remove(sw);
+	debugfs_remove_recursive(sw->debugfs_dir);
+}
+
+void tb_xdomain_debugfs_init(struct tb_xdomain *xd)
+{
+	margining_xdomain_init(xd);
+}
+
+void tb_xdomain_debugfs_remove(struct tb_xdomain *xd)
+{
+	margining_xdomain_remove(xd);
+}
+
+/**
+ * tb_service_debugfs_init() - Add debugfs directory for service
+ * @svc: Thunderbolt service pointer
+ *
+ * Adds debugfs directory for service.
+ */
+void tb_service_debugfs_init(struct tb_service *svc)
+{
+	svc->debugfs_dir = debugfs_create_dir(dev_name(&svc->dev),
+					      tb_debugfs_root);
+}
+
+/**
+ * tb_service_debugfs_remove() - Remove service debugfs directory
+ * @svc: Thunderbolt service pointer
+ *
+ * Removes the previously created debugfs directory for @svc.
+ */
+void tb_service_debugfs_remove(struct tb_service *svc)
+{
+	debugfs_remove_recursive(svc->debugfs_dir);
+	svc->debugfs_dir = NULL;
+}
+
+static int retimer_sb_regs_show(struct seq_file *s, void *not_used)
+{
+	struct tb_retimer *rt = s->private;
+	struct tb *tb = rt->tb;
+	int ret;
+
+	pm_runtime_get_sync(&rt->dev);
+
+	if (mutex_lock_interruptible(&tb->lock)) {
+		ret = -ERESTARTSYS;
+		goto out_rpm_put;
+	}
+
+	ret = sb_regs_show(rt->port, retimer_sb_regs, ARRAY_SIZE(retimer_sb_regs),
+			   USB4_SB_TARGET_RETIMER, rt->index, s);
+
+	mutex_unlock(&tb->lock);
+out_rpm_put:
+	pm_runtime_mark_last_busy(&rt->dev);
+	pm_runtime_put_autosuspend(&rt->dev);
+
+	return ret;
+}
+DEBUGFS_ATTR_RW(retimer_sb_regs);
+
+/**
+ * tb_retimer_debugfs_init() - Add debugfs directory for retimer
+ * @rt: Pointer to retimer structure
+ *
+ * Adds and populates retimer debugfs directory.
+ */
+void tb_retimer_debugfs_init(struct tb_retimer *rt)
+{
+	struct dentry *debugfs_dir;
+
+	debugfs_dir = debugfs_create_dir(dev_name(&rt->dev), tb_debugfs_root);
+	debugfs_create_file("sb_regs", DEBUGFS_MODE, debugfs_dir, rt,
+			    &retimer_sb_regs_fops);
+	margining_retimer_init(rt, debugfs_dir);
+}
+
+/**
+ * tb_retimer_debugfs_remove() - Remove retimer debugfs directory
+ * @rt: Pointer to retimer structure
+ *
+ * Removes the retimer debugfs directory along with its contents.
+ */
+void tb_retimer_debugfs_remove(struct tb_retimer *rt)
+{
+	debugfs_lookup_and_remove(dev_name(&rt->dev), tb_debugfs_root);
+	margining_retimer_remove(rt);
+}
+
+void tb_debugfs_init(void)
+{
+	tb_debugfs_root = debugfs_create_dir("thunderbolt", NULL);
+}
+
+void tb_debugfs_exit(void)
+{
+	debugfs_remove_recursive(tb_debugfs_root);
+}