[mirror_ubuntu-zesty-kernel.git] / drivers / watchdog / at91rm9200_wdt.c

/*
 * Watchdog driver for Atmel AT91RM9200 (Thunder)
 *
 *  Copyright (C) 2003 SAN People (Pty) Ltd
 *
 * 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.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/bitops.h>
#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/mfd/syscon.h>
#include <linux/mfd/syscon/atmel-st.h>
#include <linux/miscdevice.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/platform_device.h>
#include <linux/reboot.h>
#include <linux/regmap.h>
#include <linux/types.h>
#include <linux/watchdog.h>
#include <linux/uaccess.h>
#include <linux/of.h>
#include <linux/of_device.h>

#define WDT_DEFAULT_TIME	5	/* seconds */
#define WDT_MAX_TIME		256	/* seconds */

static int wdt_time = WDT_DEFAULT_TIME;
static bool nowayout = WATCHDOG_NOWAYOUT;
static struct regmap *regmap_st;

module_param(wdt_time, int, 0);
MODULE_PARM_DESC(wdt_time, "Watchdog time in seconds. (default="
				__MODULE_STRING(WDT_DEFAULT_TIME) ")");

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


static unsigned long at91wdt_busy;

/* ......................................................................... */

static int at91rm9200_restart(struct notifier_block *this,
					unsigned long mode, void *cmd)
{
	/*
	 * Perform a hardware reset with the use of the Watchdog timer.
	 */
	regmap_write(regmap_st, AT91_ST_WDMR,
		     AT91_ST_RSTEN | AT91_ST_EXTEN | 1);
	regmap_write(regmap_st, AT91_ST_CR, AT91_ST_WDRST);

	mdelay(2000);

	pr_emerg("Unable to restart system\n");
	return NOTIFY_DONE;
}

static struct notifier_block at91rm9200_restart_nb = {
	.notifier_call = at91rm9200_restart,
	.priority = 192,
};

/*
 * Disable the watchdog.
 */
static inline void at91_wdt_stop(void)
{
	regmap_write(regmap_st, AT91_ST_WDMR, AT91_ST_EXTEN);
}

/*
 * Enable and reset the watchdog.
 */
static inline void at91_wdt_start(void)
{
	regmap_write(regmap_st, AT91_ST_WDMR, AT91_ST_EXTEN | AT91_ST_RSTEN |
				(((65536 * wdt_time) >> 8) & AT91_ST_WDV));
	regmap_write(regmap_st, AT91_ST_CR, AT91_ST_WDRST);
}

/*
 * Reload the watchdog timer.  (ie, pat the watchdog)
 */
static inline void at91_wdt_reload(void)
{
	regmap_write(regmap_st, AT91_ST_CR, AT91_ST_WDRST);
}

/* ......................................................................... */

/*
 * Watchdog device is opened, and watchdog starts running.
 */
static int at91_wdt_open(struct inode *inode, struct file *file)
{
	if (test_and_set_bit(0, &at91wdt_busy))
		return -EBUSY;

	at91_wdt_start();
	return nonseekable_open(inode, file);
}

/*
 * Close the watchdog device.
 * If CONFIG_WATCHDOG_NOWAYOUT is NOT defined then the watchdog is also
 *  disabled.
 */
static int at91_wdt_close(struct inode *inode, struct file *file)
{
	/* Disable the watchdog when file is closed */
	if (!nowayout)
		at91_wdt_stop();

	clear_bit(0, &at91wdt_busy);
	return 0;
}

/*
 * Change the watchdog time interval.
 */
static int at91_wdt_settimeout(int new_time)
{
	/*
	 * All counting occurs at SLOW_CLOCK / 128 = 256 Hz
	 *
	 * Since WDV is a 16-bit counter, the maximum period is
	 * 65536 / 256 = 256 seconds.
	 */
	if ((new_time <= 0) || (new_time > WDT_MAX_TIME))
		return -EINVAL;

	/* Set new watchdog time. It will be used when
	   at91_wdt_start() is called. */
	wdt_time = new_time;
	return 0;
}

static const struct watchdog_info at91_wdt_info = {
	.identity	= "at91 watchdog",
	.options	= WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
};

/*
 * Handle commands from user-space.
 */
static long at91_wdt_ioctl(struct file *file,
					unsigned int cmd, unsigned long arg)
{
	void __user *argp = (void __user *)arg;
	int __user *p = argp;
	int new_value;

	switch (cmd) {
	case WDIOC_GETSUPPORT:
		return copy_to_user(argp, &at91_wdt_info,
				sizeof(at91_wdt_info)) ? -EFAULT : 0;
	case WDIOC_GETSTATUS:
	case WDIOC_GETBOOTSTATUS:
		return put_user(0, p);
	case WDIOC_SETOPTIONS:
		if (get_user(new_value, p))
			return -EFAULT;
		if (new_value & WDIOS_DISABLECARD)
			at91_wdt_stop();
		if (new_value & WDIOS_ENABLECARD)
			at91_wdt_start();
		return 0;
	case WDIOC_KEEPALIVE:
		at91_wdt_reload();	/* pat the watchdog */
		return 0;
	case WDIOC_SETTIMEOUT:
		if (get_user(new_value, p))
			return -EFAULT;
		if (at91_wdt_settimeout(new_value))
			return -EINVAL;
		/* Enable new time value */
		at91_wdt_start();
		/* Return current value */
		return put_user(wdt_time, p);
	case WDIOC_GETTIMEOUT:
		return put_user(wdt_time, p);
	default:
		return -ENOTTY;
	}
}

/*
 * Pat the watchdog whenever device is written to.
 */
static ssize_t at91_wdt_write(struct file *file, const char *data,
						size_t len, loff_t *ppos)
{
	at91_wdt_reload();		/* pat the watchdog */
	return len;
}

/* ......................................................................... */

static const struct file_operations at91wdt_fops = {
	.owner		= THIS_MODULE,
	.llseek		= no_llseek,
	.unlocked_ioctl	= at91_wdt_ioctl,
	.open		= at91_wdt_open,
	.release	= at91_wdt_close,
	.write		= at91_wdt_write,
};

static struct miscdevice at91wdt_miscdev = {
	.minor		= WATCHDOG_MINOR,
	.name		= "watchdog",
	.fops		= &at91wdt_fops,
};

static int at91wdt_probe(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	struct device *parent;
	int res;

	if (at91wdt_miscdev.parent)
		return -EBUSY;
	at91wdt_miscdev.parent = &pdev->dev;

	parent = dev->parent;
	if (!parent) {
		dev_err(dev, "no parent\n");
		return -ENODEV;
	}

	regmap_st = syscon_node_to_regmap(parent->of_node);
	if (IS_ERR(regmap_st))
		return -ENODEV;

	res = misc_register(&at91wdt_miscdev);
	if (res)
		return res;

	res = register_restart_handler(&at91rm9200_restart_nb);
	if (res)
		dev_warn(dev, "failed to register restart handler\n");

	pr_info("AT91 Watchdog Timer enabled (%d seconds%s)\n",
		wdt_time, nowayout ? ", nowayout" : "");
	return 0;
}

static int at91wdt_remove(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	int res;

	res = unregister_restart_handler(&at91rm9200_restart_nb);
	if (res)
		dev_warn(dev, "failed to unregister restart handler\n");

	misc_deregister(&at91wdt_miscdev);
	at91wdt_miscdev.parent = NULL;

	return res;
}

static void at91wdt_shutdown(struct platform_device *pdev)
{
	at91_wdt_stop();
}

#ifdef CONFIG_PM

static int at91wdt_suspend(struct platform_device *pdev, pm_message_t message)
{
	at91_wdt_stop();
	return 0;
}

static int at91wdt_resume(struct platform_device *pdev)
{
	if (at91wdt_busy)
		at91_wdt_start();
	return 0;
}

#else
#define at91wdt_suspend NULL
#define at91wdt_resume	NULL
#endif

static const struct of_device_id at91_wdt_dt_ids[] = {
	{ .compatible = "atmel,at91rm9200-wdt" },
	{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, at91_wdt_dt_ids);

static struct platform_driver at91wdt_driver = {
	.probe		= at91wdt_probe,
	.remove		= at91wdt_remove,
	.shutdown	= at91wdt_shutdown,
	.suspend	= at91wdt_suspend,
	.resume		= at91wdt_resume,
	.driver		= {
		.name	= "atmel_st_watchdog",
		.of_match_table = at91_wdt_dt_ids,
	},
};

static int __init at91_wdt_init(void)
{
	/* Check that the heartbeat value is within range;
	   if not reset to the default */
	if (at91_wdt_settimeout(wdt_time)) {
		at91_wdt_settimeout(WDT_DEFAULT_TIME);
		pr_info("wdt_time value must be 1 <= wdt_time <= 256, using %d\n",
			wdt_time);
	}

	return platform_driver_register(&at91wdt_driver);
}

static void __exit at91_wdt_exit(void)
{
	platform_driver_unregister(&at91wdt_driver);
}

module_init(at91_wdt_init);
module_exit(at91_wdt_exit);

MODULE_AUTHOR("Andrew Victor");
MODULE_DESCRIPTION("Watchdog driver for Atmel AT91RM9200");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:atmel_st_watchdog");
Commit	Line	Data
853807fb AV	1	/*
	2	* Watchdog driver for Atmel AT91RM9200 (Thunder)
	3	*
	4	* Copyright (C) 2003 SAN People (Pty) Ltd
	5	*
	6	* This program is free software; you can redistribute it and/or
	7	* modify it under the terms of the GNU General Public License
	8	* as published by the Free Software Foundation; either version
	9	* 2 of the License, or (at your option) any later version.
	10	*/
	11
27c766aa JP	12	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
27c766aa JP	13
1977f032	14	#include <linux/bitops.h>
9ab45f3f	15	#include <linux/delay.h>
853807fb AV	16	#include <linux/errno.h>
	17	#include <linux/fs.h>
	18	#include <linux/init.h>
02e0746e	19	#include <linux/io.h>
853807fb	20	#include <linux/kernel.h>
8432f9e5 AB	21	#include <linux/mfd/syscon.h>
8432f9e5 AB	22	#include <linux/mfd/syscon/atmel-st.h>
853807fb AV	23	#include <linux/miscdevice.h>
	24	#include <linux/module.h>
	25	#include <linux/moduleparam.h>
dfc7bd9c	26	#include <linux/platform_device.h>
9ab45f3f	27	#include <linux/reboot.h>
8432f9e5	28	#include <linux/regmap.h>
853807fb AV	29	#include <linux/types.h>
853807fb AV	30	#include <linux/watchdog.h>
2760600d	31	#include <linux/uaccess.h>
a6a1bcd3 JE	32	#include <linux/of.h>
a6a1bcd3 JE	33	#include <linux/of_device.h>
853807fb	34
dfc7bd9c AV	35	#define WDT_DEFAULT_TIME 5 /* seconds */
dfc7bd9c AV	36	#define WDT_MAX_TIME 256 /* seconds */
853807fb AV	37
853807fb AV	38	static int wdt_time = WDT_DEFAULT_TIME;
86a1e189	39	static bool nowayout = WATCHDOG_NOWAYOUT;
8432f9e5	40	static struct regmap *regmap_st;
853807fb AV	41
853807fb AV	42	module_param(wdt_time, int, 0);
2760600d AC	43	MODULE_PARM_DESC(wdt_time, "Watchdog time in seconds. (default="
2760600d AC	44	__MODULE_STRING(WDT_DEFAULT_TIME) ")");
853807fb	45
dfc7bd9c	46	#ifdef CONFIG_WATCHDOG_NOWAYOUT
86a1e189	47	module_param(nowayout, bool, 0);
2760600d AC	48	MODULE_PARM_DESC(nowayout,
	49	"Watchdog cannot be stopped once started (default="
	50	__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
dfc7bd9c	51	#endif
853807fb AV	52
	53
	54	static unsigned long at91wdt_busy;
	55
	56	/* ......................................................................... */
	57
9ab45f3f AB	58	static int at91rm9200_restart(struct notifier_block *this,
	59	unsigned long mode, void *cmd)
	60	{
	61	/*
	62	* Perform a hardware reset with the use of the Watchdog timer.
	63	*/
	64	regmap_write(regmap_st, AT91_ST_WDMR,
	65	AT91_ST_RSTEN \| AT91_ST_EXTEN \| 1);
	66	regmap_write(regmap_st, AT91_ST_CR, AT91_ST_WDRST);
	67
	68	mdelay(2000);
	69
	70	pr_emerg("Unable to restart system\n");
	71	return NOTIFY_DONE;
	72	}
	73
	74	static struct notifier_block at91rm9200_restart_nb = {
	75	.notifier_call = at91rm9200_restart,
	76	.priority = 192,
	77	};
	78
853807fb AV	79	/*
	80	* Disable the watchdog.
	81	*/
2760600d	82	static inline void at91_wdt_stop(void)
853807fb	83	{
8432f9e5	84	regmap_write(regmap_st, AT91_ST_WDMR, AT91_ST_EXTEN);
853807fb AV	85	}
	86
	87	/*
	88	* Enable and reset the watchdog.
	89	*/
2760600d	90	static inline void at91_wdt_start(void)
853807fb	91	{
8432f9e5	92	regmap_write(regmap_st, AT91_ST_WDMR, AT91_ST_EXTEN \| AT91_ST_RSTEN \|
2760600d	93	(((65536 * wdt_time) >> 8) & AT91_ST_WDV));
8432f9e5	94	regmap_write(regmap_st, AT91_ST_CR, AT91_ST_WDRST);
853807fb AV	95	}
	96
	97	/*
	98	* Reload the watchdog timer. (ie, pat the watchdog)
	99	*/
2760600d	100	static inline void at91_wdt_reload(void)
853807fb	101	{
8432f9e5	102	regmap_write(regmap_st, AT91_ST_CR, AT91_ST_WDRST);
853807fb AV	103	}
	104
	105	/* ......................................................................... */
	106
	107	/*
	108	* Watchdog device is opened, and watchdog starts running.
	109	*/
	110	static int at91_wdt_open(struct inode inode, struct file file)
	111	{
	112	if (test_and_set_bit(0, &at91wdt_busy))
	113	return -EBUSY;
	114
	115	at91_wdt_start();
	116	return nonseekable_open(inode, file);
	117	}
	118
	119	/*
	120	* Close the watchdog device.
	121	* If CONFIG_WATCHDOG_NOWAYOUT is NOT defined then the watchdog is also
	122	* disabled.
	123	*/
	124	static int at91_wdt_close(struct inode inode, struct file file)
	125	{
2760600d	126	/* Disable the watchdog when file is closed */
853807fb	127	if (!nowayout)
2760600d	128	at91_wdt_stop();
853807fb AV	129
	130	clear_bit(0, &at91wdt_busy);
	131	return 0;
	132	}
	133
	134	/*
	135	* Change the watchdog time interval.
	136	*/
	137	static int at91_wdt_settimeout(int new_time)
	138	{
	139	/*
2af29b78	140	* All counting occurs at SLOW_CLOCK / 128 = 256 Hz
853807fb AV	141	*
853807fb AV	142	* Since WDV is a 16-bit counter, the maximum period is
2af29b78	143	* 65536 / 256 = 256 seconds.
853807fb AV	144	*/
	145	if ((new_time <= 0) \|\| (new_time > WDT_MAX_TIME))
	146	return -EINVAL;
	147
2760600d AC	148	/* Set new watchdog time. It will be used when
2760600d AC	149	at91_wdt_start() is called. */
853807fb AV	150	wdt_time = new_time;
	151	return 0;
	152	}
	153
42747d71	154	static const struct watchdog_info at91_wdt_info = {
853807fb AV	155	.identity = "at91 watchdog",
	156	.options = WDIOF_SETTIMEOUT \| WDIOF_KEEPALIVEPING,
	157	};
	158
	159	/*
	160	* Handle commands from user-space.
	161	*/
3c4fafd6	162	static long at91_wdt_ioctl(struct file *file,
2760600d	163	unsigned int cmd, unsigned long arg)
853807fb AV	164	{
	165	void __user argp = (void __user )arg;
	166	int __user *p = argp;
	167	int new_value;
	168
2760600d	169	switch (cmd) {
2760600d AC	170	case WDIOC_GETSUPPORT:
	171	return copy_to_user(argp, &at91_wdt_info,
	172	sizeof(at91_wdt_info)) ? -EFAULT : 0;
2760600d AC	173	case WDIOC_GETSTATUS:
	174	case WDIOC_GETBOOTSTATUS:
	175	return put_user(0, p);
	176	case WDIOC_SETOPTIONS:
	177	if (get_user(new_value, p))
	178	return -EFAULT;
	179	if (new_value & WDIOS_DISABLECARD)
	180	at91_wdt_stop();
	181	if (new_value & WDIOS_ENABLECARD)
853807fb	182	at91_wdt_start();
2760600d	183	return 0;
0c06090c WVS	184	case WDIOC_KEEPALIVE:
	185	at91_wdt_reload(); /* pat the watchdog */
	186	return 0;
	187	case WDIOC_SETTIMEOUT:
	188	if (get_user(new_value, p))
	189	return -EFAULT;
	190	if (at91_wdt_settimeout(new_value))
	191	return -EINVAL;
	192	/* Enable new time value */
	193	at91_wdt_start();
	194	/* Return current value */
	195	return put_user(wdt_time, p);
	196	case WDIOC_GETTIMEOUT:
	197	return put_user(wdt_time, p);
2760600d AC	198	default:
2760600d AC	199	return -ENOTTY;
853807fb AV	200	}
	201	}
	202
	203	/*
	204	* Pat the watchdog whenever device is written to.
	205	*/
2760600d AC	206	static ssize_t at91_wdt_write(struct file file, const char data,
2760600d AC	207	size_t len, loff_t *ppos)
853807fb AV	208	{
	209	at91_wdt_reload(); /* pat the watchdog */
	210	return len;
	211	}
	212
	213	/* ......................................................................... */
	214
62322d25	215	static const struct file_operations at91wdt_fops = {
853807fb AV	216	.owner = THIS_MODULE,
853807fb AV	217	.llseek = no_llseek,
2760600d	218	.unlocked_ioctl = at91_wdt_ioctl,
853807fb AV	219	.open = at91_wdt_open,
	220	.release = at91_wdt_close,
	221	.write = at91_wdt_write,
	222	};
	223
	224	static struct miscdevice at91wdt_miscdev = {
	225	.minor = WATCHDOG_MINOR,
	226	.name = "watchdog",
	227	.fops = &at91wdt_fops,
	228	};
	229
2d991a16	230	static int at91wdt_probe(struct platform_device *pdev)
853807fb	231	{
8432f9e5 AB	232	struct device *dev = &pdev->dev;
8432f9e5 AB	233	struct device *parent;
853807fb AV	234	int res;
853807fb AV	235
e0b79e0b	236	if (at91wdt_miscdev.parent)
dfc7bd9c	237	return -EBUSY;
e0b79e0b	238	at91wdt_miscdev.parent = &pdev->dev;
853807fb	239
8432f9e5 AB	240	parent = dev->parent;
	241	if (!parent) {
	242	dev_err(dev, "no parent\n");
	243	return -ENODEV;
	244	}
	245
	246	regmap_st = syscon_node_to_regmap(parent->of_node);
bf5125d5	247	if (IS_ERR(regmap_st))
8432f9e5 AB	248	return -ENODEV;
8432f9e5 AB	249
853807fb AV	250	res = misc_register(&at91wdt_miscdev);
	251	if (res)
	252	return res;
	253
9ab45f3f AB	254	res = register_restart_handler(&at91rm9200_restart_nb);
	255	if (res)
	256	dev_warn(dev, "failed to register restart handler\n");
	257
27c766aa JP	258	pr_info("AT91 Watchdog Timer enabled (%d seconds%s)\n",
27c766aa JP	259	wdt_time, nowayout ? ", nowayout" : "");
853807fb AV	260	return 0;
	261	}
	262
4b12b896	263	static int at91wdt_remove(struct platform_device *pdev)
dfc7bd9c	264	{
9ab45f3f	265	struct device *dev = &pdev->dev;
dfc7bd9c AV	266	int res;
dfc7bd9c AV	267
9ab45f3f AB	268	res = unregister_restart_handler(&at91rm9200_restart_nb);
	269	if (res)
	270	dev_warn(dev, "failed to unregister restart handler\n");
	271
f368ed60 GKH	272	misc_deregister(&at91wdt_miscdev);
f368ed60 GKH	273	at91wdt_miscdev.parent = NULL;
dfc7bd9c AV	274
	275	return res;
	276	}
	277
	278	static void at91wdt_shutdown(struct platform_device *pdev)
	279	{
	280	at91_wdt_stop();
	281	}
	282
	283	#ifdef CONFIG_PM
	284
	285	static int at91wdt_suspend(struct platform_device *pdev, pm_message_t message)
	286	{
	287	at91_wdt_stop();
	288	return 0;
	289	}
	290
	291	static int at91wdt_resume(struct platform_device *pdev)
	292	{
	293	if (at91wdt_busy)
	294	at91_wdt_start();
95f62bdc	295	return 0;
dfc7bd9c AV	296	}
	297
	298	#else
	299	#define at91wdt_suspend NULL
	300	#define at91wdt_resume NULL
	301	#endif
	302
a6a1bcd3 JE	303	static const struct of_device_id at91_wdt_dt_ids[] = {
	304	{ .compatible = "atmel,at91rm9200-wdt" },
	305	{ /* sentinel */ }
	306	};
	307	MODULE_DEVICE_TABLE(of, at91_wdt_dt_ids);
	308
dfc7bd9c AV	309	static struct platform_driver at91wdt_driver = {
dfc7bd9c AV	310	.probe = at91wdt_probe,
82268714	311	.remove = at91wdt_remove,
dfc7bd9c AV	312	.shutdown = at91wdt_shutdown,
	313	.suspend = at91wdt_suspend,
	314	.resume = at91wdt_resume,
	315	.driver = {
8432f9e5	316	.name = "atmel_st_watchdog",
85eee819	317	.of_match_table = at91_wdt_dt_ids,
dfc7bd9c AV	318	},
	319	};
	320
	321	static int __init at91_wdt_init(void)
	322	{
2760600d AC	323	/* Check that the heartbeat value is within range;
2760600d AC	324	if not reset to the default */
dfc7bd9c AV	325	if (at91_wdt_settimeout(wdt_time)) {
dfc7bd9c AV	326	at91_wdt_settimeout(WDT_DEFAULT_TIME);
27c766aa JP	327	pr_info("wdt_time value must be 1 <= wdt_time <= 256, using %d\n",
27c766aa JP	328	wdt_time);
dfc7bd9c AV	329	}
	330
	331	return platform_driver_register(&at91wdt_driver);
	332	}
	333
853807fb AV	334	static void __exit at91_wdt_exit(void)
853807fb AV	335	{
dfc7bd9c	336	platform_driver_unregister(&at91wdt_driver);
853807fb AV	337	}
	338
	339	module_init(at91_wdt_init);
	340	module_exit(at91_wdt_exit);
	341
	342	MODULE_AUTHOR("Andrew Victor");
	343	MODULE_DESCRIPTION("Watchdog driver for Atmel AT91RM9200");
	344	MODULE_LICENSE("GPL");
8432f9e5	345	MODULE_ALIAS("platform:atmel_st_watchdog");