[deliverable/linux.git] / drivers / char / watchdog / at91_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.
 */

#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/miscdevice.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/platform_device.h>
#include <linux/types.h>
#include <linux/watchdog.h>
#include <asm/bitops.h>
#include <asm/uaccess.h>


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

static int wdt_time = WDT_DEFAULT_TIME;
static int nowayout = WATCHDOG_NOWAYOUT;

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


static unsigned long at91wdt_busy;

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

/*
 * Disable the watchdog.
 */
static void inline at91_wdt_stop(void)
{
	at91_sys_write(AT91_ST_WDMR, AT91_ST_EXTEN);
}

/*
 * Enable and reset the watchdog.
 */
static void inline at91_wdt_start(void)
{
	at91_sys_write(AT91_ST_WDMR, AT91_ST_EXTEN | AT91_ST_RSTEN | (((65536 * wdt_time) >> 8) & AT91_ST_WDV));
	at91_sys_write(AT91_ST_CR, AT91_ST_WDRST);
}

/*
 * Reload the watchdog timer.  (ie, pat the watchdog)
 */
static void inline at91_wdt_reload(void)
{
	at91_sys_write(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)
{
	if (!nowayout)
		at91_wdt_stop();	/* Disable the watchdog when file is closed */

	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 = 0.256 Hz
	 *
	 * Since WDV is a 16-bit counter, the maximum period is
	 * 65536 / 0.256 = 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 struct watchdog_info at91_wdt_info = {
	.identity	= "at91 watchdog",
	.options	= WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
};

/*
 * Handle commands from user-space.
 */
static int at91_wdt_ioctl(struct inode *inode, 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_KEEPALIVE:
			at91_wdt_reload();	/* pat the watchdog */
			return 0;

		case WDIOC_GETSUPPORT:
			return copy_to_user(argp, &at91_wdt_info, sizeof(at91_wdt_info)) ? -EFAULT : 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);

		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;

		default:
			return -ENOIOCTLCMD;
	}
}

/*
 * 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,
	.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 __init at91wdt_probe(struct platform_device *pdev)
{
	int res;

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

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

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

static int __exit at91wdt_remove(struct platform_device *pdev)
{
	int res;

	res = misc_deregister(&at91wdt_miscdev);
	if (!res)
		at91wdt_miscdev.dev = 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 struct platform_driver at91wdt_driver = {
	.probe		= at91wdt_probe,
	.remove		= __exit_p(at91wdt_remove),
	.shutdown	= at91wdt_shutdown,
	.suspend	= at91wdt_suspend,
	.resume		= at91wdt_resume,
	.driver		= {
		.name	= "at91_wdt",
		.owner	= THIS_MODULE,
	},
};

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("at91_wdt: 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_MISCDEV(WATCHDOG_MINOR);
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
853807fb AV	12	#include <linux/errno.h>
	13	#include <linux/fs.h>
	14	#include <linux/init.h>
	15	#include <linux/kernel.h>
	16	#include <linux/miscdevice.h>
	17	#include <linux/module.h>
	18	#include <linux/moduleparam.h>
dfc7bd9c	19	#include <linux/platform_device.h>
853807fb AV	20	#include <linux/types.h>
	21	#include <linux/watchdog.h>
	22	#include <asm/bitops.h>
	23	#include <asm/uaccess.h>
	24
	25
dfc7bd9c AV	26	#define WDT_DEFAULT_TIME 5 /* seconds */
dfc7bd9c AV	27	#define WDT_MAX_TIME 256 /* seconds */
853807fb AV	28
	29	static int wdt_time = WDT_DEFAULT_TIME;
	30	static int nowayout = WATCHDOG_NOWAYOUT;
	31
	32	module_param(wdt_time, int, 0);
	33	MODULE_PARM_DESC(wdt_time, "Watchdog time in seconds. (default="__MODULE_STRING(WDT_DEFAULT_TIME) ")");
	34
dfc7bd9c	35	#ifdef CONFIG_WATCHDOG_NOWAYOUT
853807fb AV	36	module_param(nowayout, int, 0);
853807fb AV	37	MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
dfc7bd9c	38	#endif
853807fb AV	39
	40
	41	static unsigned long at91wdt_busy;
	42
	43	/* ......................................................................... */
	44
	45	/*
	46	* Disable the watchdog.
	47	*/
	48	static void inline at91_wdt_stop(void)
	49	{
	50	at91_sys_write(AT91_ST_WDMR, AT91_ST_EXTEN);
	51	}
	52
	53	/*
	54	* Enable and reset the watchdog.
	55	*/
	56	static void inline at91_wdt_start(void)
	57	{
	58	at91_sys_write(AT91_ST_WDMR, AT91_ST_EXTEN \| AT91_ST_RSTEN \| (((65536 * wdt_time) >> 8) & AT91_ST_WDV));
	59	at91_sys_write(AT91_ST_CR, AT91_ST_WDRST);
	60	}
	61
	62	/*
	63	* Reload the watchdog timer. (ie, pat the watchdog)
	64	*/
	65	static void inline at91_wdt_reload(void)
	66	{
	67	at91_sys_write(AT91_ST_CR, AT91_ST_WDRST);
	68	}
	69
	70	/* ......................................................................... */
	71
	72	/*
	73	* Watchdog device is opened, and watchdog starts running.
	74	*/
	75	static int at91_wdt_open(struct inode inode, struct file file)
	76	{
	77	if (test_and_set_bit(0, &at91wdt_busy))
	78	return -EBUSY;
	79
	80	at91_wdt_start();
	81	return nonseekable_open(inode, file);
	82	}
	83
	84	/*
	85	* Close the watchdog device.
	86	* If CONFIG_WATCHDOG_NOWAYOUT is NOT defined then the watchdog is also
	87	* disabled.
	88	*/
	89	static int at91_wdt_close(struct inode inode, struct file file)
	90	{
	91	if (!nowayout)
	92	at91_wdt_stop(); /* Disable the watchdog when file is closed */
	93
	94	clear_bit(0, &at91wdt_busy);
	95	return 0;
	96	}
	97
	98	/*
	99	* Change the watchdog time interval.
	100	*/
	101	static int at91_wdt_settimeout(int new_time)
	102	{
103	/*
104	* All counting occurs at SLOW_CLOCK / 128 = 0.256 Hz
105	*
106	* Since WDV is a 16-bit counter, the maximum period is
107	* 65536 / 0.256 = 256 seconds.
108	*/
109	if ((new_time <= 0) \|\| (new_time > WDT_MAX_TIME))
110	return -EINVAL;
111
112	/* Set new watchdog time. It will be used when at91_wdt_start() is called. */
113	wdt_time = new_time;
114	return 0;
115	}
116
117	static struct watchdog_info at91_wdt_info = {
118	.identity = "at91 watchdog",
119	.options = WDIOF_SETTIMEOUT \| WDIOF_KEEPALIVEPING,
120	};
121
122	/*
123	* Handle commands from user-space.
124	*/
125	static int at91_wdt_ioctl(struct inode inode, struct file file,
126	unsigned int cmd, unsigned long arg)
127	{
128	void __user argp = (void __user )arg;
129	int __user *p = argp;
130	int new_value;
131
132	switch(cmd) {
133	case WDIOC_KEEPALIVE:
134	at91_wdt_reload(); /* pat the watchdog */
135	return 0;
136
137	case WDIOC_GETSUPPORT:
138	return copy_to_user(argp, &at91_wdt_info, sizeof(at91_wdt_info)) ? -EFAULT : 0;
139
140	case WDIOC_SETTIMEOUT:
141	if (get_user(new_value, p))
142	return -EFAULT;
dfc7bd9c	143
853807fb AV	144	if (at91_wdt_settimeout(new_value))
	145	return -EINVAL;
	146
	147	/* Enable new time value */
	148	at91_wdt_start();
	149
	150	/* Return current value */
	151	return put_user(wdt_time, p);
	152
	153	case WDIOC_GETTIMEOUT:
	154	return put_user(wdt_time, p);
	155
	156	case WDIOC_GETSTATUS:
	157	case WDIOC_GETBOOTSTATUS:
	158	return put_user(0, p);
	159
	160	case WDIOC_SETOPTIONS:
	161	if (get_user(new_value, p))
	162	return -EFAULT;
	163
	164	if (new_value & WDIOS_DISABLECARD)
	165	at91_wdt_stop();
	166	if (new_value & WDIOS_ENABLECARD)
	167	at91_wdt_start();
	168	return 0;
	169
	170	default:
	171	return -ENOIOCTLCMD;
	172	}
	173	}
	174
	175	/*
	176	* Pat the watchdog whenever device is written to.
	177	*/
	178	static ssize_t at91_wdt_write(struct file file, const char data, size_t len, loff_t *ppos)
	179	{
	180	at91_wdt_reload(); /* pat the watchdog */
	181	return len;
	182	}
	183
	184	/* ......................................................................... */
	185
62322d25	186	static const struct file_operations at91wdt_fops = {
853807fb AV	187	.owner = THIS_MODULE,
	188	.llseek = no_llseek,
	189	.ioctl = at91_wdt_ioctl,
	190	.open = at91_wdt_open,
	191	.release = at91_wdt_close,
	192	.write = at91_wdt_write,
	193	};
	194
	195	static struct miscdevice at91wdt_miscdev = {
	196	.minor = WATCHDOG_MINOR,
	197	.name = "watchdog",
	198	.fops = &at91wdt_fops,
	199	};
	200
dfc7bd9c	201	static int __init at91wdt_probe(struct platform_device *pdev)
853807fb AV	202	{
	203	int res;
	204
dfc7bd9c AV	205	if (at91wdt_miscdev.dev)
	206	return -EBUSY;
	207	at91wdt_miscdev.dev = &pdev->dev;
853807fb AV	208
	209	res = misc_register(&at91wdt_miscdev);
	210	if (res)
	211	return res;
	212
dfc7bd9c	213	printk("AT91 Watchdog Timer enabled (%d seconds%s)\n", wdt_time, nowayout ? ", nowayout" : "");
853807fb AV	214	return 0;
	215	}
	216
dfc7bd9c AV	217	static int __exit at91wdt_remove(struct platform_device *pdev)
	218	{
	219	int res;
	220
	221	res = misc_deregister(&at91wdt_miscdev);
	222	if (!res)
	223	at91wdt_miscdev.dev = NULL;
	224
	225	return res;
	226	}
	227
	228	static void at91wdt_shutdown(struct platform_device *pdev)
	229	{
	230	at91_wdt_stop();
	231	}
	232
	233	#ifdef CONFIG_PM
	234
	235	static int at91wdt_suspend(struct platform_device *pdev, pm_message_t message)
	236	{
	237	at91_wdt_stop();
	238	return 0;
	239	}
	240
	241	static int at91wdt_resume(struct platform_device *pdev)
	242	{
	243	if (at91wdt_busy)
	244	at91_wdt_start();
	245	return 0;
	246	}
	247
	248	#else
	249	#define at91wdt_suspend NULL
	250	#define at91wdt_resume NULL
	251	#endif
	252
	253	static struct platform_driver at91wdt_driver = {
	254	.probe = at91wdt_probe,
	255	.remove = __exit_p(at91wdt_remove),
	256	.shutdown = at91wdt_shutdown,
	257	.suspend = at91wdt_suspend,
	258	.resume = at91wdt_resume,
	259	.driver = {
	260	.name = "at91_wdt",
	261	.owner = THIS_MODULE,
	262	},
	263	};
	264
	265	static int __init at91_wdt_init(void)
	266	{
	267	/* Check that the heartbeat value is within range; if not reset to the default */
	268	if (at91_wdt_settimeout(wdt_time)) {
	269	at91_wdt_settimeout(WDT_DEFAULT_TIME);
	270	pr_info("at91_wdt: wdt_time value must be 1 <= wdt_time <= 256, using %d\n", wdt_time);
	271	}
	272
	273	return platform_driver_register(&at91wdt_driver);
	274	}
	275
853807fb AV	276	static void __exit at91_wdt_exit(void)
853807fb AV	277	{
dfc7bd9c	278	platform_driver_unregister(&at91wdt_driver);
853807fb AV	279	}
	280
	281	module_init(at91_wdt_init);
	282	module_exit(at91_wdt_exit);
	283
	284	MODULE_AUTHOR("Andrew Victor");
	285	MODULE_DESCRIPTION("Watchdog driver for Atmel AT91RM9200");
	286	MODULE_LICENSE("GPL");
	287	MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);