drivers/usb/dwc3/debugfs.c

/**
 * debugfs.c - DesignWare USB3 DRD Controller DebugFS file
 *
 * Copyright (C) 2010-2011 Texas Instruments Incorporated - http://www.ti.com
 *
 * Authors: Felipe Balbi <balbi@ti.com>,
 *	    Sebastian Andrzej Siewior <bigeasy@linutronix.de>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions, and the following disclaimer,
 *    without modification.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The names of the above-listed copyright holders may not be used
 *    to endorse or promote products derived from this software without
 *    specific prior written permission.
 *
 * ALTERNATIVELY, this software may be distributed under the terms of the
 * GNU General Public License ("GPL") version 2, as published by the Free
 * Software Foundation.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/ptrace.h>
#include <linux/types.h>
#include <linux/spinlock.h>
#include <linux/debugfs.h>
#include <linux/seq_file.h>
#include <linux/delay.h>
#include <linux/uaccess.h>

#include <linux/usb/ch9.h>

#include "core.h"
#include "gadget.h"
#include "io.h"
#include "debug.h"

#define dump_register(nm)				\
{							\
	.name	= __stringify(nm),			\
	.offset	= DWC3_ ##nm - DWC3_GLOBALS_REGS_START,	\
}

static const struct debugfs_reg32 dwc3_regs[] = {
	dump_register(GSBUSCFG0),
	dump_register(GSBUSCFG1),
	dump_register(GTXTHRCFG),
	dump_register(GRXTHRCFG),
	dump_register(GCTL),
	dump_register(GEVTEN),
	dump_register(GSTS),
	dump_register(GSNPSID),
	dump_register(GGPIO),
	dump_register(GUID),
	dump_register(GUCTL),
	dump_register(GBUSERRADDR0),
	dump_register(GBUSERRADDR1),
	dump_register(GPRTBIMAP0),
	dump_register(GPRTBIMAP1),
	dump_register(GHWPARAMS0),
	dump_register(GHWPARAMS1),
	dump_register(GHWPARAMS2),
	dump_register(GHWPARAMS3),
	dump_register(GHWPARAMS4),
	dump_register(GHWPARAMS5),
	dump_register(GHWPARAMS6),
	dump_register(GHWPARAMS7),
	dump_register(GDBGFIFOSPACE),
	dump_register(GDBGLTSSM),
	dump_register(GPRTBIMAP_HS0),
	dump_register(GPRTBIMAP_HS1),
	dump_register(GPRTBIMAP_FS0),
	dump_register(GPRTBIMAP_FS1),

	dump_register(GUSB2PHYCFG(0)),
	dump_register(GUSB2PHYCFG(1)),
	dump_register(GUSB2PHYCFG(2)),
	dump_register(GUSB2PHYCFG(3)),
	dump_register(GUSB2PHYCFG(4)),
	dump_register(GUSB2PHYCFG(5)),
	dump_register(GUSB2PHYCFG(6)),
	dump_register(GUSB2PHYCFG(7)),
	dump_register(GUSB2PHYCFG(8)),
	dump_register(GUSB2PHYCFG(9)),
	dump_register(GUSB2PHYCFG(10)),
	dump_register(GUSB2PHYCFG(11)),
	dump_register(GUSB2PHYCFG(12)),
	dump_register(GUSB2PHYCFG(13)),
	dump_register(GUSB2PHYCFG(14)),
	dump_register(GUSB2PHYCFG(15)),

	dump_register(GUSB2I2CCTL(0)),
	dump_register(GUSB2I2CCTL(1)),
	dump_register(GUSB2I2CCTL(2)),
	dump_register(GUSB2I2CCTL(3)),
	dump_register(GUSB2I2CCTL(4)),
	dump_register(GUSB2I2CCTL(5)),
	dump_register(GUSB2I2CCTL(6)),
	dump_register(GUSB2I2CCTL(7)),
	dump_register(GUSB2I2CCTL(8)),
	dump_register(GUSB2I2CCTL(9)),
	dump_register(GUSB2I2CCTL(10)),
	dump_register(GUSB2I2CCTL(11)),
	dump_register(GUSB2I2CCTL(12)),
	dump_register(GUSB2I2CCTL(13)),
	dump_register(GUSB2I2CCTL(14)),
	dump_register(GUSB2I2CCTL(15)),

	dump_register(GUSB2PHYACC(0)),
	dump_register(GUSB2PHYACC(1)),
	dump_register(GUSB2PHYACC(2)),
	dump_register(GUSB2PHYACC(3)),
	dump_register(GUSB2PHYACC(4)),
	dump_register(GUSB2PHYACC(5)),
	dump_register(GUSB2PHYACC(6)),
	dump_register(GUSB2PHYACC(7)),
	dump_register(GUSB2PHYACC(8)),
	dump_register(GUSB2PHYACC(9)),
	dump_register(GUSB2PHYACC(10)),
	dump_register(GUSB2PHYACC(11)),
	dump_register(GUSB2PHYACC(12)),
	dump_register(GUSB2PHYACC(13)),
	dump_register(GUSB2PHYACC(14)),
	dump_register(GUSB2PHYACC(15)),

	dump_register(GUSB3PIPECTL(0)),
	dump_register(GUSB3PIPECTL(1)),
	dump_register(GUSB3PIPECTL(2)),
	dump_register(GUSB3PIPECTL(3)),
	dump_register(GUSB3PIPECTL(4)),
	dump_register(GUSB3PIPECTL(5)),
	dump_register(GUSB3PIPECTL(6)),
	dump_register(GUSB3PIPECTL(7)),
	dump_register(GUSB3PIPECTL(8)),
	dump_register(GUSB3PIPECTL(9)),
	dump_register(GUSB3PIPECTL(10)),
	dump_register(GUSB3PIPECTL(11)),
	dump_register(GUSB3PIPECTL(12)),
	dump_register(GUSB3PIPECTL(13)),
	dump_register(GUSB3PIPECTL(14)),
	dump_register(GUSB3PIPECTL(15)),

	dump_register(GTXFIFOSIZ(0)),
	dump_register(GTXFIFOSIZ(1)),
	dump_register(GTXFIFOSIZ(2)),
	dump_register(GTXFIFOSIZ(3)),
	dump_register(GTXFIFOSIZ(4)),
	dump_register(GTXFIFOSIZ(5)),
	dump_register(GTXFIFOSIZ(6)),
	dump_register(GTXFIFOSIZ(7)),
	dump_register(GTXFIFOSIZ(8)),
	dump_register(GTXFIFOSIZ(9)),
	dump_register(GTXFIFOSIZ(10)),
	dump_register(GTXFIFOSIZ(11)),
	dump_register(GTXFIFOSIZ(12)),
	dump_register(GTXFIFOSIZ(13)),
	dump_register(GTXFIFOSIZ(14)),
	dump_register(GTXFIFOSIZ(15)),
	dump_register(GTXFIFOSIZ(16)),
	dump_register(GTXFIFOSIZ(17)),
	dump_register(GTXFIFOSIZ(18)),
	dump_register(GTXFIFOSIZ(19)),
	dump_register(GTXFIFOSIZ(20)),
	dump_register(GTXFIFOSIZ(21)),
	dump_register(GTXFIFOSIZ(22)),
	dump_register(GTXFIFOSIZ(23)),
	dump_register(GTXFIFOSIZ(24)),
	dump_register(GTXFIFOSIZ(25)),
	dump_register(GTXFIFOSIZ(26)),
	dump_register(GTXFIFOSIZ(27)),
	dump_register(GTXFIFOSIZ(28)),
	dump_register(GTXFIFOSIZ(29)),
	dump_register(GTXFIFOSIZ(30)),
	dump_register(GTXFIFOSIZ(31)),

	dump_register(GRXFIFOSIZ(0)),
	dump_register(GRXFIFOSIZ(1)),
	dump_register(GRXFIFOSIZ(2)),
	dump_register(GRXFIFOSIZ(3)),
	dump_register(GRXFIFOSIZ(4)),
	dump_register(GRXFIFOSIZ(5)),
	dump_register(GRXFIFOSIZ(6)),
	dump_register(GRXFIFOSIZ(7)),
	dump_register(GRXFIFOSIZ(8)),
	dump_register(GRXFIFOSIZ(9)),
	dump_register(GRXFIFOSIZ(10)),
	dump_register(GRXFIFOSIZ(11)),
	dump_register(GRXFIFOSIZ(12)),
	dump_register(GRXFIFOSIZ(13)),
	dump_register(GRXFIFOSIZ(14)),
	dump_register(GRXFIFOSIZ(15)),
	dump_register(GRXFIFOSIZ(16)),
	dump_register(GRXFIFOSIZ(17)),
	dump_register(GRXFIFOSIZ(18)),
	dump_register(GRXFIFOSIZ(19)),
	dump_register(GRXFIFOSIZ(20)),
	dump_register(GRXFIFOSIZ(21)),
	dump_register(GRXFIFOSIZ(22)),
	dump_register(GRXFIFOSIZ(23)),
	dump_register(GRXFIFOSIZ(24)),
	dump_register(GRXFIFOSIZ(25)),
	dump_register(GRXFIFOSIZ(26)),
	dump_register(GRXFIFOSIZ(27)),
	dump_register(GRXFIFOSIZ(28)),
	dump_register(GRXFIFOSIZ(29)),
	dump_register(GRXFIFOSIZ(30)),
	dump_register(GRXFIFOSIZ(31)),

	dump_register(GEVNTADRLO(0)),
	dump_register(GEVNTADRHI(0)),
	dump_register(GEVNTSIZ(0)),
	dump_register(GEVNTCOUNT(0)),

	dump_register(GHWPARAMS8),
	dump_register(DCFG),
	dump_register(DCTL),
	dump_register(DEVTEN),
	dump_register(DSTS),
	dump_register(DGCMDPAR),
	dump_register(DGCMD),
	dump_register(DALEPENA),

	dump_register(DEPCMDPAR2(0)),
	dump_register(DEPCMDPAR2(1)),
	dump_register(DEPCMDPAR2(2)),
	dump_register(DEPCMDPAR2(3)),
	dump_register(DEPCMDPAR2(4)),
	dump_register(DEPCMDPAR2(5)),
	dump_register(DEPCMDPAR2(6)),
	dump_register(DEPCMDPAR2(7)),
	dump_register(DEPCMDPAR2(8)),
	dump_register(DEPCMDPAR2(9)),
	dump_register(DEPCMDPAR2(10)),
	dump_register(DEPCMDPAR2(11)),
	dump_register(DEPCMDPAR2(12)),
	dump_register(DEPCMDPAR2(13)),
	dump_register(DEPCMDPAR2(14)),
	dump_register(DEPCMDPAR2(15)),
	dump_register(DEPCMDPAR2(16)),
	dump_register(DEPCMDPAR2(17)),
	dump_register(DEPCMDPAR2(18)),
	dump_register(DEPCMDPAR2(19)),
	dump_register(DEPCMDPAR2(20)),
	dump_register(DEPCMDPAR2(21)),
	dump_register(DEPCMDPAR2(22)),
	dump_register(DEPCMDPAR2(23)),
	dump_register(DEPCMDPAR2(24)),
	dump_register(DEPCMDPAR2(25)),
	dump_register(DEPCMDPAR2(26)),
	dump_register(DEPCMDPAR2(27)),
	dump_register(DEPCMDPAR2(28)),
	dump_register(DEPCMDPAR2(29)),
	dump_register(DEPCMDPAR2(30)),
	dump_register(DEPCMDPAR2(31)),

	dump_register(DEPCMDPAR1(0)),
	dump_register(DEPCMDPAR1(1)),
	dump_register(DEPCMDPAR1(2)),
	dump_register(DEPCMDPAR1(3)),
	dump_register(DEPCMDPAR1(4)),
	dump_register(DEPCMDPAR1(5)),
	dump_register(DEPCMDPAR1(6)),
	dump_register(DEPCMDPAR1(7)),
	dump_register(DEPCMDPAR1(8)),
	dump_register(DEPCMDPAR1(9)),
	dump_register(DEPCMDPAR1(10)),
	dump_register(DEPCMDPAR1(11)),
	dump_register(DEPCMDPAR1(12)),
	dump_register(DEPCMDPAR1(13)),
	dump_register(DEPCMDPAR1(14)),
	dump_register(DEPCMDPAR1(15)),
	dump_register(DEPCMDPAR1(16)),
	dump_register(DEPCMDPAR1(17)),
	dump_register(DEPCMDPAR1(18)),
	dump_register(DEPCMDPAR1(19)),
	dump_register(DEPCMDPAR1(20)),
	dump_register(DEPCMDPAR1(21)),
	dump_register(DEPCMDPAR1(22)),
	dump_register(DEPCMDPAR1(23)),
	dump_register(DEPCMDPAR1(24)),
	dump_register(DEPCMDPAR1(25)),
	dump_register(DEPCMDPAR1(26)),
	dump_register(DEPCMDPAR1(27)),
	dump_register(DEPCMDPAR1(28)),
	dump_register(DEPCMDPAR1(29)),
	dump_register(DEPCMDPAR1(30)),
	dump_register(DEPCMDPAR1(31)),

	dump_register(DEPCMDPAR0(0)),
	dump_register(DEPCMDPAR0(1)),
	dump_register(DEPCMDPAR0(2)),
	dump_register(DEPCMDPAR0(3)),
	dump_register(DEPCMDPAR0(4)),
	dump_register(DEPCMDPAR0(5)),
	dump_register(DEPCMDPAR0(6)),
	dump_register(DEPCMDPAR0(7)),
	dump_register(DEPCMDPAR0(8)),
	dump_register(DEPCMDPAR0(9)),
	dump_register(DEPCMDPAR0(10)),
	dump_register(DEPCMDPAR0(11)),
	dump_register(DEPCMDPAR0(12)),
	dump_register(DEPCMDPAR0(13)),
	dump_register(DEPCMDPAR0(14)),
	dump_register(DEPCMDPAR0(15)),
	dump_register(DEPCMDPAR0(16)),
	dump_register(DEPCMDPAR0(17)),
	dump_register(DEPCMDPAR0(18)),
	dump_register(DEPCMDPAR0(19)),
	dump_register(DEPCMDPAR0(20)),
	dump_register(DEPCMDPAR0(21)),
	dump_register(DEPCMDPAR0(22)),
	dump_register(DEPCMDPAR0(23)),
	dump_register(DEPCMDPAR0(24)),
	dump_register(DEPCMDPAR0(25)),
	dump_register(DEPCMDPAR0(26)),
	dump_register(DEPCMDPAR0(27)),
	dump_register(DEPCMDPAR0(28)),
	dump_register(DEPCMDPAR0(29)),
	dump_register(DEPCMDPAR0(30)),
	dump_register(DEPCMDPAR0(31)),

	dump_register(DEPCMD(0)),
	dump_register(DEPCMD(1)),
	dump_register(DEPCMD(2)),
	dump_register(DEPCMD(3)),
	dump_register(DEPCMD(4)),
	dump_register(DEPCMD(5)),
	dump_register(DEPCMD(6)),
	dump_register(DEPCMD(7)),
	dump_register(DEPCMD(8)),
	dump_register(DEPCMD(9)),
	dump_register(DEPCMD(10)),
	dump_register(DEPCMD(11)),
	dump_register(DEPCMD(12)),
	dump_register(DEPCMD(13)),
	dump_register(DEPCMD(14)),
	dump_register(DEPCMD(15)),
	dump_register(DEPCMD(16)),
	dump_register(DEPCMD(17)),
	dump_register(DEPCMD(18)),
	dump_register(DEPCMD(19)),
	dump_register(DEPCMD(20)),
	dump_register(DEPCMD(21)),
	dump_register(DEPCMD(22)),
	dump_register(DEPCMD(23)),
	dump_register(DEPCMD(24)),
	dump_register(DEPCMD(25)),
	dump_register(DEPCMD(26)),
	dump_register(DEPCMD(27)),
	dump_register(DEPCMD(28)),
	dump_register(DEPCMD(29)),
	dump_register(DEPCMD(30)),
	dump_register(DEPCMD(31)),

	dump_register(OCFG),
	dump_register(OCTL),
	dump_register(OEVT),
	dump_register(OEVTEN),
	dump_register(OSTS),
};

static int dwc3_mode_show(struct seq_file *s, void *unused)
{
	struct dwc3		*dwc = s->private;
	unsigned long		flags;
	u32			reg;

	spin_lock_irqsave(&dwc->lock, flags);
	reg = dwc3_readl(dwc->regs, DWC3_GCTL);
	spin_unlock_irqrestore(&dwc->lock, flags);

	switch (DWC3_GCTL_PRTCAP(reg)) {
	case DWC3_GCTL_PRTCAP_HOST:
		seq_printf(s, "host\n");
		break;
	case DWC3_GCTL_PRTCAP_DEVICE:
		seq_printf(s, "device\n");
		break;
	case DWC3_GCTL_PRTCAP_OTG:
		seq_printf(s, "OTG\n");
		break;
	default:
		seq_printf(s, "UNKNOWN %08x\n", DWC3_GCTL_PRTCAP(reg));
	}

	return 0;
}

static int dwc3_mode_open(struct inode *inode, struct file *file)
{
	return single_open(file, dwc3_mode_show, inode->i_private);
}

static ssize_t dwc3_mode_write(struct file *file,
		const char __user *ubuf, size_t count, loff_t *ppos)
{
	struct seq_file		*s = file->private_data;
	struct dwc3		*dwc = s->private;
	unsigned long		flags;
	u32			mode = 0;
	char			buf[32];

	if (copy_from_user(&buf, ubuf, min_t(size_t, sizeof(buf) - 1, count)))
		return -EFAULT;

	if (!strncmp(buf, "host", 4))
		mode |= DWC3_GCTL_PRTCAP_HOST;

	if (!strncmp(buf, "device", 6))
		mode |= DWC3_GCTL_PRTCAP_DEVICE;

	if (!strncmp(buf, "otg", 3))
		mode |= DWC3_GCTL_PRTCAP_OTG;

	if (mode) {
		spin_lock_irqsave(&dwc->lock, flags);
		dwc3_set_mode(dwc, mode);
		spin_unlock_irqrestore(&dwc->lock, flags);
	}
	return count;
}

static const struct file_operations dwc3_mode_fops = {
	.open			= dwc3_mode_open,
	.write			= dwc3_mode_write,
	.read			= seq_read,
	.llseek			= seq_lseek,
	.release		= single_release,
};

static int dwc3_testmode_show(struct seq_file *s, void *unused)
{
	struct dwc3		*dwc = s->private;
	unsigned long		flags;
	u32			reg;

	spin_lock_irqsave(&dwc->lock, flags);
	reg = dwc3_readl(dwc->regs, DWC3_DCTL);
	reg &= DWC3_DCTL_TSTCTRL_MASK;
	reg >>= 1;
	spin_unlock_irqrestore(&dwc->lock, flags);

	switch (reg) {
	case 0:
		seq_printf(s, "no test\n");
		break;
	case TEST_J:
		seq_printf(s, "test_j\n");
		break;
	case TEST_K:
		seq_printf(s, "test_k\n");
		break;
	case TEST_SE0_NAK:
		seq_printf(s, "test_se0_nak\n");
		break;
	case TEST_PACKET:
		seq_printf(s, "test_packet\n");
		break;
	case TEST_FORCE_EN:
		seq_printf(s, "test_force_enable\n");
		break;
	default:
		seq_printf(s, "UNKNOWN %d\n", reg);
	}

	return 0;
}

static int dwc3_testmode_open(struct inode *inode, struct file *file)
{
	return single_open(file, dwc3_testmode_show, inode->i_private);
}

static ssize_t dwc3_testmode_write(struct file *file,
		const char __user *ubuf, size_t count, loff_t *ppos)
{
	struct seq_file		*s = file->private_data;
	struct dwc3		*dwc = s->private;
	unsigned long		flags;
	u32			testmode = 0;
	char			buf[32];

	if (copy_from_user(&buf, ubuf, min_t(size_t, sizeof(buf) - 1, count)))
		return -EFAULT;

	if (!strncmp(buf, "test_j", 6))
		testmode = TEST_J;
	else if (!strncmp(buf, "test_k", 6))
		testmode = TEST_K;
	else if (!strncmp(buf, "test_se0_nak", 12))
		testmode = TEST_SE0_NAK;
	else if (!strncmp(buf, "test_packet", 11))
		testmode = TEST_PACKET;
	else if (!strncmp(buf, "test_force_enable", 17))
		testmode = TEST_FORCE_EN;
	else
		testmode = 0;

	spin_lock_irqsave(&dwc->lock, flags);
	dwc3_gadget_set_test_mode(dwc, testmode);
	spin_unlock_irqrestore(&dwc->lock, flags);

	return count;
}

static const struct file_operations dwc3_testmode_fops = {
	.open			= dwc3_testmode_open,
	.write			= dwc3_testmode_write,
	.read			= seq_read,
	.llseek			= seq_lseek,
	.release		= single_release,
};

static int dwc3_link_state_show(struct seq_file *s, void *unused)
{
	struct dwc3		*dwc = s->private;
	unsigned long		flags;
	enum dwc3_link_state	state;
	u32			reg;

	spin_lock_irqsave(&dwc->lock, flags);
	reg = dwc3_readl(dwc->regs, DWC3_DSTS);
	state = DWC3_DSTS_USBLNKST(reg);
	spin_unlock_irqrestore(&dwc->lock, flags);

	switch (state) {
	case DWC3_LINK_STATE_U0:
		seq_printf(s, "U0\n");
		break;
	case DWC3_LINK_STATE_U1:
		seq_printf(s, "U1\n");
		break;
	case DWC3_LINK_STATE_U2:
		seq_printf(s, "U2\n");
		break;
	case DWC3_LINK_STATE_U3:
		seq_printf(s, "U3\n");
		break;
	case DWC3_LINK_STATE_SS_DIS:
		seq_printf(s, "SS.Disabled\n");
		break;
	case DWC3_LINK_STATE_RX_DET:
		seq_printf(s, "Rx.Detect\n");
		break;
	case DWC3_LINK_STATE_SS_INACT:
		seq_printf(s, "SS.Inactive\n");
		break;
	case DWC3_LINK_STATE_POLL:
		seq_printf(s, "Poll\n");
		break;
	case DWC3_LINK_STATE_RECOV:
		seq_printf(s, "Recovery\n");
		break;
	case DWC3_LINK_STATE_HRESET:
		seq_printf(s, "HRESET\n");
		break;
	case DWC3_LINK_STATE_CMPLY:
		seq_printf(s, "Compliance\n");
		break;
	case DWC3_LINK_STATE_LPBK:
		seq_printf(s, "Loopback\n");
		break;
	case DWC3_LINK_STATE_RESET:
		seq_printf(s, "Reset\n");
		break;
	case DWC3_LINK_STATE_RESUME:
		seq_printf(s, "Resume\n");
		break;
	default:
		seq_printf(s, "UNKNOWN %d\n", state);
	}

	return 0;
}

static int dwc3_link_state_open(struct inode *inode, struct file *file)
{
	return single_open(file, dwc3_link_state_show, inode->i_private);
}

static ssize_t dwc3_link_state_write(struct file *file,
		const char __user *ubuf, size_t count, loff_t *ppos)
{
	struct seq_file		*s = file->private_data;
	struct dwc3		*dwc = s->private;
	unsigned long		flags;
	enum dwc3_link_state	state = 0;
	char			buf[32];

	if (copy_from_user(&buf, ubuf, min_t(size_t, sizeof(buf) - 1, count)))
		return -EFAULT;

	if (!strncmp(buf, "SS.Disabled", 11))
		state = DWC3_LINK_STATE_SS_DIS;
	else if (!strncmp(buf, "Rx.Detect", 9))
		state = DWC3_LINK_STATE_RX_DET;
	else if (!strncmp(buf, "SS.Inactive", 11))
		state = DWC3_LINK_STATE_SS_INACT;
	else if (!strncmp(buf, "Recovery", 8))
		state = DWC3_LINK_STATE_RECOV;
	else if (!strncmp(buf, "Compliance", 10))
		state = DWC3_LINK_STATE_CMPLY;
	else if (!strncmp(buf, "Loopback", 8))
		state = DWC3_LINK_STATE_LPBK;
	else
		return -EINVAL;

	spin_lock_irqsave(&dwc->lock, flags);
	dwc3_gadget_set_link_state(dwc, state);
	spin_unlock_irqrestore(&dwc->lock, flags);

	return count;
}

static const struct file_operations dwc3_link_state_fops = {
	.open			= dwc3_link_state_open,
	.write			= dwc3_link_state_write,
	.read			= seq_read,
	.llseek			= seq_lseek,
	.release		= single_release,
};

int dwc3_debugfs_init(struct dwc3 *dwc)
{
	struct dentry		*root;
	struct dentry		*file;
	int			ret;

	root = debugfs_create_dir(dev_name(dwc->dev), NULL);
	if (!root) {
		ret = -ENOMEM;
		goto err0;
	}

	dwc->root = root;

	dwc->regset = kzalloc(sizeof(*dwc->regset), GFP_KERNEL);
	if (!dwc->regset) {
		ret = -ENOMEM;
		goto err1;
	}

	dwc->regset->regs = dwc3_regs;
	dwc->regset->nregs = ARRAY_SIZE(dwc3_regs);
	dwc->regset->base = dwc->regs;

	file = debugfs_create_regset32("regdump", S_IRUGO, root, dwc->regset);
	if (!file) {
		ret = -ENOMEM;
		goto err1;
	}

	if (IS_ENABLED(CONFIG_USB_DWC3_DUAL_ROLE)) {
		file = debugfs_create_file("mode", S_IRUGO | S_IWUSR, root,
				dwc, &dwc3_mode_fops);
		if (!file) {
			ret = -ENOMEM;
			goto err1;
		}
	}

	if (IS_ENABLED(CONFIG_USB_DWC3_DUAL_ROLE) ||
			IS_ENABLED(CONFIG_USB_DWC3_GADGET)) {
		file = debugfs_create_file("testmode", S_IRUGO | S_IWUSR, root,
				dwc, &dwc3_testmode_fops);
		if (!file) {
			ret = -ENOMEM;
			goto err1;
		}

		file = debugfs_create_file("link_state", S_IRUGO | S_IWUSR, root,
				dwc, &dwc3_link_state_fops);
		if (!file) {
			ret = -ENOMEM;
			goto err1;
		}
	}

	return 0;

err1:
	debugfs_remove_recursive(root);

err0:
	return ret;
}

void dwc3_debugfs_exit(struct dwc3 *dwc)
{
	debugfs_remove_recursive(dwc->root);
	dwc->root = NULL;
}