path: root/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"
#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

#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

#if IS_ENABLED(CONFIG_USB4_DEBUGFS_MARGINING)
/**
 * struct tb_margining - Lane margining support
 * @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)
 * @time_steps: Number of time margin steps
 * @max_time_offset: Maximum time margin offset (in mUI)
 * @software: %true if software margining is used instead of hardware
 * @time: %