[mirror_ubuntu-bionic-kernel.git] / drivers / watchdog / dw_wdt.c

/*
 * Copyright 2010-2011 Picochip Ltd., Jamie Iles
 * http://www.picochip.com
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 *
 * This file implements a driver for the Synopsys DesignWare watchdog device
 * in the many subsystems. The watchdog has 16 different timeout periods
 * and these are a function of the input clock frequency.
 *
 * The DesignWare watchdog cannot be stopped once it has been started so we
 * use a software timer to implement a ping that will keep the watchdog alive.
 * If we receive an expected close for the watchdog then we keep the timer
 * running, otherwise the timer is stopped and the watchdog will expire.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/bitops.h>
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/fs.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/miscdevice.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/notifier.h>
#include <linux/of.h>
#include <linux/pm.h>
#include <linux/platform_device.h>
#include <linux/reboot.h>
#include <linux/timer.h>
#include <linux/uaccess.h>
#include <linux/watchdog.h>

#define WDOG_CONTROL_REG_OFFSET		    0x00
#define WDOG_CONTROL_REG_WDT_EN_MASK	    0x01
#define WDOG_TIMEOUT_RANGE_REG_OFFSET	    0x04
#define WDOG_TIMEOUT_RANGE_TOPINIT_SHIFT    4
#define WDOG_CURRENT_COUNT_REG_OFFSET	    0x08
#define WDOG_COUNTER_RESTART_REG_OFFSET     0x0c
#define WDOG_COUNTER_RESTART_KICK_VALUE	    0x76

/* The maximum TOP (timeout period) value that can be set in the watchdog. */
#define DW_WDT_MAX_TOP		15

#define DW_WDT_DEFAULT_SECONDS	30

static bool nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
		 "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");

#define WDT_TIMEOUT		(HZ / 2)

static struct {
	void __iomem		*regs;
	struct clk		*clk;
	unsigned long		in_use;
	unsigned long		next_heartbeat;
	struct timer_list	timer;
	int			expect_close;
	struct notifier_block	restart_handler;
} dw_wdt;

static inline int dw_wdt_is_enabled(void)
{
	return readl(dw_wdt.regs + WDOG_CONTROL_REG_OFFSET) &
		WDOG_CONTROL_REG_WDT_EN_MASK;
}

static inline int dw_wdt_top_in_seconds(unsigned top)
{
	/*
	 * There are 16 possible timeout values in 0..15 where the number of
	 * cycles is 2 ^ (16 + i) and the watchdog counts down.
	 */
	return (1U << (16 + top)) / clk_get_rate(dw_wdt.clk);
}

static int dw_wdt_get_top(void)
{
	int top = readl(dw_wdt.regs + WDOG_TIMEOUT_RANGE_REG_OFFSET) & 0xF;

	return dw_wdt_top_in_seconds(top);
}

static inline void dw_wdt_set_next_heartbeat(void)
{
	dw_wdt.next_heartbeat = jiffies + dw_wdt_get_top() * HZ;
}

static void dw_wdt_keepalive(void)
{
	writel(WDOG_COUNTER_RESTART_KICK_VALUE, dw_wdt.regs +
	       WDOG_COUNTER_RESTART_REG_OFFSET);
}

static int dw_wdt_set_top(unsigned top_s)
{
	int i, top_val = DW_WDT_MAX_TOP;

	/*
	 * Iterate over the timeout values until we find the closest match. We
	 * always look for >=.
	 */
	for (i = 0; i <= DW_WDT_MAX_TOP; ++i)
		if (dw_wdt_top_in_seconds(i) >= top_s) {
			top_val = i;
			break;
		}

	/*
	 * Set the new value in the watchdog.  Some versions of dw_wdt
	 * have have TOPINIT in the TIMEOUT_RANGE register (as per
	 * CP_WDT_DUAL_TOP in WDT_COMP_PARAMS_1).  On those we
	 * effectively get a pat of the watchdog right here.
	 */
	writel(top_val | top_val << WDOG_TIMEOUT_RANGE_TOPINIT_SHIFT,
		dw_wdt.regs + WDOG_TIMEOUT_RANGE_REG_OFFSET);

	/*
	 * Add an explicit pat to handle versions of the watchdog that
	 * don't have TOPINIT.  This won't hurt on versions that have
	 * it.
	 */
	dw_wdt_keepalive();

	dw_wdt_set_next_heartbeat();

	return dw_wdt_top_in_seconds(top_val);
}

static int dw_wdt_restart_handle(struct notifier_block *this,
				unsigned long mode, void *cmd)
{
	u32 val;

	writel(0, dw_wdt.regs + WDOG_TIMEOUT_RANGE_REG_OFFSET);
	val = readl(dw_wdt.regs + WDOG_CONTROL_REG_OFFSET);
	if (val & WDOG_CONTROL_REG_WDT_EN_MASK)
		writel(WDOG_COUNTER_RESTART_KICK_VALUE, dw_wdt.regs +
			WDOG_COUNTER_RESTART_REG_OFFSET);
	else
		writel(WDOG_CONTROL_REG_WDT_EN_MASK,
		       dw_wdt.regs + WDOG_CONTROL_REG_OFFSET);

	/* wait for reset to assert... */
	mdelay(500);

	return NOTIFY_DONE;
}

static void dw_wdt_ping(unsigned long data)
{
	if (time_before(jiffies, dw_wdt.next_heartbeat) ||
	    (!nowayout && !dw_wdt.in_use)) {
		dw_wdt_keepalive();
		mod_timer(&dw_wdt.timer, jiffies + WDT_TIMEOUT);
	} else
		pr_crit("keepalive missed, machine will reset\n");
}

static int dw_wdt_open(struct inode *inode, struct file *filp)
{
	if (test_and_set_bit(0, &dw_wdt.in_use))
		return -EBUSY;

	/* Make sure we don't get unloaded. */
	__module_get(THIS_MODULE);

	if (!dw_wdt_is_enabled()) {
		/*
		 * The watchdog is not currently enabled. Set the timeout to
		 * something reasonable and then start it.
		 */
		dw_wdt_set_top(DW_WDT_DEFAULT_SECONDS);
		writel(WDOG_CONTROL_REG_WDT_EN_MASK,
		       dw_wdt.regs + WDOG_CONTROL_REG_OFFSET);
	}

	dw_wdt_set_next_heartbeat();

	return nonseekable_open(inode, filp);
}

static ssize_t dw_wdt_write(struct file *filp, const char __user *buf,
			    size_t len, loff_t *offset)
{
	if (!len)
		return 0;

	if (!nowayout) {
		size_t i;

		dw_wdt.expect_close = 0;

		for (i = 0; i < len; ++i) {
			char c;

			if (get_user(c, buf + i))
				return -EFAULT;

			if (c == 'V') {
				dw_wdt.expect_close = 1;
				break;
			}
		}
	}

	dw_wdt_set_next_heartbeat();
	dw_wdt_keepalive();
	mod_timer(&dw_wdt.timer, jiffies + WDT_TIMEOUT);

	return len;
}

static u32 dw_wdt_time_left(void)
{
	return readl(dw_wdt.regs + WDOG_CURRENT_COUNT_REG_OFFSET) /
		clk_get_rate(dw_wdt.clk);
}

static const struct watchdog_info dw_wdt_ident = {
	.options	= WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT |
			  WDIOF_MAGICCLOSE,
	.identity	= "Synopsys DesignWare Watchdog",
};

static long dw_wdt_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
{
	unsigned long val;
	int timeout;

	switch (cmd) {
	case WDIOC_GETSUPPORT:
		return copy_to_user((void __user *)arg, &dw_wdt_ident,
				    sizeof(dw_wdt_ident)) ? -EFAULT : 0;

	case WDIOC_GETSTATUS:
	case WDIOC_GETBOOTSTATUS:
		return put_user(0, (int __user *)arg);

	case WDIOC_KEEPALIVE:
		dw_wdt_set_next_heartbeat();
		return 0;

	case WDIOC_SETTIMEOUT:
		if (get_user(val, (int __user *)arg))
			return -EFAULT;
		timeout = dw_wdt_set_top(val);
		return put_user(timeout , (int __user *)arg);

	case WDIOC_GETTIMEOUT:
		return put_user(dw_wdt_get_top(), (int __user *)arg);

	case WDIOC_GETTIMELEFT:
		/* Get the time left until expiry. */
		if (get_user(val, (int __user *)arg))
			return -EFAULT;
		return put_user(dw_wdt_time_left(), (int __user *)arg);

	default:
		return -ENOTTY;
	}
}

static int dw_wdt_release(struct inode *inode, struct file *filp)
{
	clear_bit(0, &dw_wdt.in_use);

	if (!dw_wdt.expect_close) {
		del_timer(&dw_wdt.timer);

		if (!nowayout)
			pr_crit("unexpected close, system will reboot soon\n");
		else
			pr_crit("watchdog cannot be disabled, system will reboot soon\n");
	}

	dw_wdt.expect_close = 0;

	return 0;
}

#ifdef CONFIG_PM_SLEEP
static int dw_wdt_suspend(struct device *dev)
{
	clk_disable_unprepare(dw_wdt.clk);

	return 0;
}

static int dw_wdt_resume(struct device *dev)
{
	int err = clk_prepare_enable(dw_wdt.clk);

	if (err)
		return err;

	dw_wdt_keepalive();

	return 0;
}
#endif /* CONFIG_PM_SLEEP */

static SIMPLE_DEV_PM_OPS(dw_wdt_pm_ops, dw_wdt_suspend, dw_wdt_resume);

static const struct file_operations wdt_fops = {
	.owner		= THIS_MODULE,
	.llseek		= no_llseek,
	.open		= dw_wdt_open,
	.write		= dw_wdt_write,
	.unlocked_ioctl	= dw_wdt_ioctl,
	.release	= dw_wdt_release
};

static struct miscdevice dw_wdt_miscdev = {
	.fops		= &wdt_fops,
	.name		= "watchdog",
	.minor		= WATCHDOG_MINOR,
};

static int dw_wdt_drv_probe(struct platform_device *pdev)
{
	int ret;
	struct resource *mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);

	dw_wdt.regs = devm_ioremap_resource(&pdev->dev, mem);
	if (IS_ERR(dw_wdt.regs))
		return PTR_ERR(dw_wdt.regs);

	dw_wdt.clk = devm_clk_get(&pdev->dev, NULL);
	if (IS_ERR(dw_wdt.clk))
		return PTR_ERR(dw_wdt.clk);

	ret = clk_prepare_enable(dw_wdt.clk);
	if (ret)
		return ret;

	ret = misc_register(&dw_wdt_miscdev);
	if (ret)
		goto out_disable_clk;

	dw_wdt.restart_handler.notifier_call = dw_wdt_restart_handle;
	dw_wdt.restart_handler.priority = 128;
	ret = register_restart_handler(&dw_wdt.restart_handler);
	if (ret)
		pr_warn("cannot register restart handler\n");

	dw_wdt_set_next_heartbeat();
	setup_timer(&dw_wdt.timer, dw_wdt_ping, 0);
	mod_timer(&dw_wdt.timer, jiffies + WDT_TIMEOUT);

	return 0;

out_disable_clk:
	clk_disable_unprepare(dw_wdt.clk);

	return ret;
}

static int dw_wdt_drv_remove(struct platform_device *pdev)
{
	unregister_restart_handler(&dw_wdt.restart_handler);

	misc_deregister(&dw_wdt_miscdev);

	clk_disable_unprepare(dw_wdt.clk);

	return 0;
}

#ifdef CONFIG_OF
static const struct of_device_id dw_wdt_of_match[] = {
	{ .compatible = "snps,dw-wdt", },
	{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, dw_wdt_of_match);
#endif

static struct platform_driver dw_wdt_driver = {
	.probe		= dw_wdt_drv_probe,
	.remove		= dw_wdt_drv_remove,
	.driver		= {
		.name	= "dw_wdt",
		.of_match_table = of_match_ptr(dw_wdt_of_match),
		.pm	= &dw_wdt_pm_ops,
	},
};

module_platform_driver(dw_wdt_driver);

MODULE_AUTHOR("Jamie Iles");
MODULE_DESCRIPTION("Synopsys DesignWare Watchdog Driver");
MODULE_LICENSE("GPL");
Commit	Line	Data
c9353ae1 JI	1	/*
	2	* Copyright 2010-2011 Picochip Ltd., Jamie Iles
	3	* http://www.picochip.com
	4	*
	5	* This program is free software; you can redistribute it and/or
	6	* modify it under the terms of the GNU General Public License
	7	* as published by the Free Software Foundation; either version
	8	* 2 of the License, or (at your option) any later version.
	9	*
	10	* This file implements a driver for the Synopsys DesignWare watchdog device
58a251f2	11	* in the many subsystems. The watchdog has 16 different timeout periods
c9353ae1 JI	12	* and these are a function of the input clock frequency.
	13	*
	14	* The DesignWare watchdog cannot be stopped once it has been started so we
	15	* use a software timer to implement a ping that will keep the watchdog alive.
	16	* If we receive an expected close for the watchdog then we keep the timer
	17	* running, otherwise the timer is stopped and the watchdog will expire.
	18	*/
27c766aa JP	19
27c766aa JP	20	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
c9353ae1 JI	21
	22	#include <linux/bitops.h>
	23	#include <linux/clk.h>
31228f43	24	#include <linux/delay.h>
c9353ae1 JI	25	#include <linux/device.h>
	26	#include <linux/err.h>
	27	#include <linux/fs.h>
	28	#include <linux/io.h>
	29	#include <linux/kernel.h>
	30	#include <linux/miscdevice.h>
	31	#include <linux/module.h>
	32	#include <linux/moduleparam.h>
31228f43	33	#include <linux/notifier.h>
58e56373	34	#include <linux/of.h>
c9353ae1 JI	35	#include <linux/pm.h>
c9353ae1 JI	36	#include <linux/platform_device.h>
31228f43	37	#include <linux/reboot.h>
c9353ae1 JI	38	#include <linux/timer.h>
	39	#include <linux/uaccess.h>
	40	#include <linux/watchdog.h>
	41
	42	#define WDOG_CONTROL_REG_OFFSET 0x00
	43	#define WDOG_CONTROL_REG_WDT_EN_MASK 0x01
	44	#define WDOG_TIMEOUT_RANGE_REG_OFFSET 0x04
dfa07141	45	#define WDOG_TIMEOUT_RANGE_TOPINIT_SHIFT 4
c9353ae1 JI	46	#define WDOG_CURRENT_COUNT_REG_OFFSET 0x08
	47	#define WDOG_COUNTER_RESTART_REG_OFFSET 0x0c
	48	#define WDOG_COUNTER_RESTART_KICK_VALUE 0x76
	49
	50	/* The maximum TOP (timeout period) value that can be set in the watchdog. */
	51	#define DW_WDT_MAX_TOP 15
	52
b5ade9bc DA	53	#define DW_WDT_DEFAULT_SECONDS 30
b5ade9bc DA	54
86a1e189 WVS	55	static bool nowayout = WATCHDOG_NOWAYOUT;
86a1e189 WVS	56	module_param(nowayout, bool, 0);
c9353ae1 JI	57	MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
	58	"(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
	59
	60	#define WDT_TIMEOUT (HZ / 2)
	61
	62	static struct {
c9353ae1 JI	63	void __iomem *regs;
	64	struct clk *clk;
	65	unsigned long in_use;
	66	unsigned long next_heartbeat;
	67	struct timer_list timer;
	68	int expect_close;
31228f43	69	struct notifier_block restart_handler;
c9353ae1 JI	70	} dw_wdt;
	71
	72	static inline int dw_wdt_is_enabled(void)
	73	{
	74	return readl(dw_wdt.regs + WDOG_CONTROL_REG_OFFSET) &
	75	WDOG_CONTROL_REG_WDT_EN_MASK;
	76	}
	77
	78	static inline int dw_wdt_top_in_seconds(unsigned top)
	79	{
	80	/*
	81	* There are 16 possible timeout values in 0..15 where the number of
	82	* cycles is 2 ^ (16 + i) and the watchdog counts down.
	83	*/
3024e0d1	84	return (1U << (16 + top)) / clk_get_rate(dw_wdt.clk);
c9353ae1 JI	85	}
	86
	87	static int dw_wdt_get_top(void)
	88	{
	89	int top = readl(dw_wdt.regs + WDOG_TIMEOUT_RANGE_REG_OFFSET) & 0xF;
	90
	91	return dw_wdt_top_in_seconds(top);
	92	}
	93
	94	static inline void dw_wdt_set_next_heartbeat(void)
	95	{
	96	dw_wdt.next_heartbeat = jiffies + dw_wdt_get_top() * HZ;
	97	}
	98
a0085010 DA	99	static void dw_wdt_keepalive(void)
	100	{
	101	writel(WDOG_COUNTER_RESTART_KICK_VALUE, dw_wdt.regs +
	102	WDOG_COUNTER_RESTART_REG_OFFSET);
	103	}
	104
c9353ae1 JI	105	static int dw_wdt_set_top(unsigned top_s)
	106	{
	107	int i, top_val = DW_WDT_MAX_TOP;
	108
	109	/*
	110	* Iterate over the timeout values until we find the closest match. We
	111	* always look for >=.
	112	*/
	113	for (i = 0; i <= DW_WDT_MAX_TOP; ++i)
	114	if (dw_wdt_top_in_seconds(i) >= top_s) {
	115	top_val = i;
	116	break;
	117	}
	118
a0085010 DA	119	/*
	120	* Set the new value in the watchdog. Some versions of dw_wdt
	121	* have have TOPINIT in the TIMEOUT_RANGE register (as per
	122	* CP_WDT_DUAL_TOP in WDT_COMP_PARAMS_1). On those we
	123	* effectively get a pat of the watchdog right here.
	124	*/
dfa07141 JZ	125	writel(top_val \| top_val << WDOG_TIMEOUT_RANGE_TOPINIT_SHIFT,
dfa07141 JZ	126	dw_wdt.regs + WDOG_TIMEOUT_RANGE_REG_OFFSET);
c9353ae1	127
a0085010 DA	128	/*
	129	* Add an explicit pat to handle versions of the watchdog that
	130	* don't have TOPINIT. This won't hurt on versions that have
	131	* it.
	132	*/
	133	dw_wdt_keepalive();
	134
c9353ae1 JI	135	dw_wdt_set_next_heartbeat();
	136
	137	return dw_wdt_top_in_seconds(top_val);
	138	}
	139
31228f43 JZ	140	static int dw_wdt_restart_handle(struct notifier_block *this,
	141	unsigned long mode, void *cmd)
	142	{
	143	u32 val;
	144
	145	writel(0, dw_wdt.regs + WDOG_TIMEOUT_RANGE_REG_OFFSET);
	146	val = readl(dw_wdt.regs + WDOG_CONTROL_REG_OFFSET);
	147	if (val & WDOG_CONTROL_REG_WDT_EN_MASK)
	148	writel(WDOG_COUNTER_RESTART_KICK_VALUE, dw_wdt.regs +
	149	WDOG_COUNTER_RESTART_REG_OFFSET);
	150	else
	151	writel(WDOG_CONTROL_REG_WDT_EN_MASK,
	152	dw_wdt.regs + WDOG_CONTROL_REG_OFFSET);
	153
	154	/* wait for reset to assert... */
	155	mdelay(500);
	156
	157	return NOTIFY_DONE;
	158	}
	159
c9353ae1 JI	160	static void dw_wdt_ping(unsigned long data)
	161	{
	162	if (time_before(jiffies, dw_wdt.next_heartbeat) \|\|
	163	(!nowayout && !dw_wdt.in_use)) {
	164	dw_wdt_keepalive();
	165	mod_timer(&dw_wdt.timer, jiffies + WDT_TIMEOUT);
	166	} else
	167	pr_crit("keepalive missed, machine will reset\n");
	168	}
	169
	170	static int dw_wdt_open(struct inode inode, struct file filp)
	171	{
	172	if (test_and_set_bit(0, &dw_wdt.in_use))
	173	return -EBUSY;
	174
	175	/* Make sure we don't get unloaded. */
	176	__module_get(THIS_MODULE);
	177
c9353ae1 JI	178	if (!dw_wdt_is_enabled()) {
	179	/*
	180	* The watchdog is not currently enabled. Set the timeout to
b5ade9bc	181	* something reasonable and then start it.
c9353ae1	182	*/
b5ade9bc	183	dw_wdt_set_top(DW_WDT_DEFAULT_SECONDS);
c9353ae1 JI	184	writel(WDOG_CONTROL_REG_WDT_EN_MASK,
	185	dw_wdt.regs + WDOG_CONTROL_REG_OFFSET);
	186	}
	187
	188	dw_wdt_set_next_heartbeat();
	189
c9353ae1 JI	190	return nonseekable_open(inode, filp);
	191	}
	192
0b930261 SK	193	static ssize_t dw_wdt_write(struct file filp, const char __user buf,
0b930261 SK	194	size_t len, loff_t *offset)
c9353ae1 JI	195	{
	196	if (!len)
	197	return 0;
	198
	199	if (!nowayout) {
	200	size_t i;
	201
	202	dw_wdt.expect_close = 0;
	203
	204	for (i = 0; i < len; ++i) {
	205	char c;
	206
	207	if (get_user(c, buf + i))
	208	return -EFAULT;
	209
	210	if (c == 'V') {
	211	dw_wdt.expect_close = 1;
	212	break;
	213	}
	214	}
	215	}
	216
	217	dw_wdt_set_next_heartbeat();
04b1a62e	218	dw_wdt_keepalive();
c9353ae1 JI	219	mod_timer(&dw_wdt.timer, jiffies + WDT_TIMEOUT);
	220
	221	return len;
	222	}
	223
	224	static u32 dw_wdt_time_left(void)
	225	{
	226	return readl(dw_wdt.regs + WDOG_CURRENT_COUNT_REG_OFFSET) /
	227	clk_get_rate(dw_wdt.clk);
	228	}
	229
	230	static const struct watchdog_info dw_wdt_ident = {
	231	.options = WDIOF_KEEPALIVEPING \| WDIOF_SETTIMEOUT \|
	232	WDIOF_MAGICCLOSE,
	233	.identity = "Synopsys DesignWare Watchdog",
	234	};
	235
	236	static long dw_wdt_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
	237	{
	238	unsigned long val;
	239	int timeout;
	240
	241	switch (cmd) {
	242	case WDIOC_GETSUPPORT:
60295507	243	return copy_to_user((void __user *)arg, &dw_wdt_ident,
c9353ae1 JI	244	sizeof(dw_wdt_ident)) ? -EFAULT : 0;
	245
	246	case WDIOC_GETSTATUS:
	247	case WDIOC_GETBOOTSTATUS:
60295507	248	return put_user(0, (int __user *)arg);
c9353ae1 JI	249
	250	case WDIOC_KEEPALIVE:
	251	dw_wdt_set_next_heartbeat();
	252	return 0;
	253
	254	case WDIOC_SETTIMEOUT:
	255	if (get_user(val, (int __user *)arg))
	256	return -EFAULT;
	257	timeout = dw_wdt_set_top(val);
	258	return put_user(timeout , (int __user *)arg);
	259
	260	case WDIOC_GETTIMEOUT:
	261	return put_user(dw_wdt_get_top(), (int __user *)arg);
	262
	263	case WDIOC_GETTIMELEFT:
	264	/* Get the time left until expiry. */
	265	if (get_user(val, (int __user *)arg))
	266	return -EFAULT;
	267	return put_user(dw_wdt_time_left(), (int __user *)arg);
	268
	269	default:
	270	return -ENOTTY;
	271	}
	272	}
	273
	274	static int dw_wdt_release(struct inode inode, struct file filp)
	275	{
	276	clear_bit(0, &dw_wdt.in_use);
	277
	278	if (!dw_wdt.expect_close) {
	279	del_timer(&dw_wdt.timer);
	280
	281	if (!nowayout)
	282	pr_crit("unexpected close, system will reboot soon\n");
	283	else
	284	pr_crit("watchdog cannot be disabled, system will reboot soon\n");
	285	}
	286
	287	dw_wdt.expect_close = 0;
	288
	289	return 0;
	290	}
	291
ad83c6cb	292	#ifdef CONFIG_PM_SLEEP
c9353ae1 JI	293	static int dw_wdt_suspend(struct device *dev)
c9353ae1 JI	294	{
280103e6	295	clk_disable_unprepare(dw_wdt.clk);
c9353ae1 JI	296
	297	return 0;
	298	}
	299
	300	static int dw_wdt_resume(struct device *dev)
	301	{
280103e6	302	int err = clk_prepare_enable(dw_wdt.clk);
c9353ae1 JI	303
	304	if (err)
	305	return err;
	306
	307	dw_wdt_keepalive();
	308
	309	return 0;
	310	}
ad83c6cb	311	#endif /* CONFIG_PM_SLEEP */
c9353ae1	312
ad83c6cb	313	static SIMPLE_DEV_PM_OPS(dw_wdt_pm_ops, dw_wdt_suspend, dw_wdt_resume);
c9353ae1 JI	314
	315	static const struct file_operations wdt_fops = {
	316	.owner = THIS_MODULE,
	317	.llseek = no_llseek,
	318	.open = dw_wdt_open,
	319	.write = dw_wdt_write,
	320	.unlocked_ioctl = dw_wdt_ioctl,
	321	.release = dw_wdt_release
	322	};
	323
	324	static struct miscdevice dw_wdt_miscdev = {
	325	.fops = &wdt_fops,
	326	.name = "watchdog",
	327	.minor = WATCHDOG_MINOR,
	328	};
	329
2d991a16	330	static int dw_wdt_drv_probe(struct platform_device *pdev)
c9353ae1 JI	331	{
	332	int ret;
	333	struct resource *mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	334
4c271bb6 TR	335	dw_wdt.regs = devm_ioremap_resource(&pdev->dev, mem);
	336	if (IS_ERR(dw_wdt.regs))
	337	return PTR_ERR(dw_wdt.regs);
c9353ae1	338
cf3cc8c2	339	dw_wdt.clk = devm_clk_get(&pdev->dev, NULL);
c9353ae1 JI	340	if (IS_ERR(dw_wdt.clk))
	341	return PTR_ERR(dw_wdt.clk);
	342
280103e6	343	ret = clk_prepare_enable(dw_wdt.clk);
c9353ae1	344	if (ret)
cf3cc8c2	345	return ret;
c9353ae1	346
c9353ae1 JI	347	ret = misc_register(&dw_wdt_miscdev);
	348	if (ret)
	349	goto out_disable_clk;
	350
31228f43 JZ	351	dw_wdt.restart_handler.notifier_call = dw_wdt_restart_handle;
	352	dw_wdt.restart_handler.priority = 128;
	353	ret = register_restart_handler(&dw_wdt.restart_handler);
	354	if (ret)
	355	pr_warn("cannot register restart handler\n");
	356
c9353ae1 JI	357	dw_wdt_set_next_heartbeat();
	358	setup_timer(&dw_wdt.timer, dw_wdt_ping, 0);
	359	mod_timer(&dw_wdt.timer, jiffies + WDT_TIMEOUT);
	360
	361	return 0;
	362
	363	out_disable_clk:
280103e6	364	clk_disable_unprepare(dw_wdt.clk);
c9353ae1 JI	365
	366	return ret;
	367	}
	368
4b12b896	369	static int dw_wdt_drv_remove(struct platform_device *pdev)
c9353ae1	370	{
31228f43 JZ	371	unregister_restart_handler(&dw_wdt.restart_handler);
31228f43 JZ	372
c9353ae1 JI	373	misc_deregister(&dw_wdt_miscdev);
c9353ae1 JI	374
280103e6	375	clk_disable_unprepare(dw_wdt.clk);
c9353ae1 JI	376
	377	return 0;
	378	}
	379
58e56373 DN	380	#ifdef CONFIG_OF
	381	static const struct of_device_id dw_wdt_of_match[] = {
	382	{ .compatible = "snps,dw-wdt", },
	383	{ /* sentinel */ }
	384	};
	385	MODULE_DEVICE_TABLE(of, dw_wdt_of_match);
	386	#endif
	387
c9353ae1 JI	388	static struct platform_driver dw_wdt_driver = {
c9353ae1 JI	389	.probe = dw_wdt_drv_probe,
82268714	390	.remove = dw_wdt_drv_remove,
c9353ae1 JI	391	.driver = {
c9353ae1 JI	392	.name = "dw_wdt",
58e56373	393	.of_match_table = of_match_ptr(dw_wdt_of_match),
c9353ae1	394	.pm = &dw_wdt_pm_ops,
c9353ae1 JI	395	},
	396	};
	397
b8ec6118	398	module_platform_driver(dw_wdt_driver);
c9353ae1 JI	399
	400	MODULE_AUTHOR("Jamie Iles");
	401	MODULE_DESCRIPTION("Synopsys DesignWare Watchdog Driver");
	402	MODULE_LICENSE("GPL");