linux/drivers/thunderbolt/debugfs.c

// 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 <linux/uaccess.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;

	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 = 7;

	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_RO(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);

/**
 * 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);

	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);
	}
}

/**
 * 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)
{
	debugfs_remove_recursive(sw->debugfs_dir);
}

void tb_debugfs_init(void)
{
	tb_debugfs_root = debugfs_create_dir("thunderbolt", NULL);
}

void tb_debugfs_exit(void)
{
	debugfs_remove_recursive(tb_debugfs_root);
}