[net-next-2.6.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.
 */

#include <linux/bitops.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/io.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 <linux/uaccess.h>
#include <mach/at91_st.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 inline void at91_wdt_stop(void)
{
	at91_sys_write(AT91_ST_WDMR, AT91_ST_EXTEN);
}

/*
 * Enable and reset the watchdog.
 */
static inline void 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 inline void 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)
{
	/* 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 __devinit at91wdt_probe(struct platform_device *pdev)
{
	int res;

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

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

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

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

	res = misc_deregister(&at91wdt_miscdev);
	if (!res)
		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 struct platform_driver at91wdt_driver = {
	.probe		= at91wdt_probe,
	.remove		= __devexit_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);
MODULE_ALIAS("platform:at91_wdt");
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
1977f032	12	#include <linux/bitops.h>
853807fb AV	13	#include <linux/errno.h>
	14	#include <linux/fs.h>
	15	#include <linux/init.h>
02e0746e	16	#include <linux/io.h>
853807fb AV	17	#include <linux/kernel.h>
	18	#include <linux/miscdevice.h>
	19	#include <linux/module.h>
	20	#include <linux/moduleparam.h>
dfc7bd9c	21	#include <linux/platform_device.h>
853807fb AV	22	#include <linux/types.h>
853807fb AV	23	#include <linux/watchdog.h>
2760600d	24	#include <linux/uaccess.h>
a09e64fb	25	#include <mach/at91_st.h>
853807fb	26
dfc7bd9c AV	27	#define WDT_DEFAULT_TIME 5 /* seconds */
dfc7bd9c AV	28	#define WDT_MAX_TIME 256 /* seconds */
853807fb AV	29
	30	static int wdt_time = WDT_DEFAULT_TIME;
	31	static int nowayout = WATCHDOG_NOWAYOUT;
	32
	33	module_param(wdt_time, int, 0);
2760600d AC	34	MODULE_PARM_DESC(wdt_time, "Watchdog time in seconds. (default="
2760600d AC	35	__MODULE_STRING(WDT_DEFAULT_TIME) ")");
853807fb	36
dfc7bd9c	37	#ifdef CONFIG_WATCHDOG_NOWAYOUT
853807fb	38	module_param(nowayout, int, 0);
2760600d AC	39	MODULE_PARM_DESC(nowayout,
	40	"Watchdog cannot be stopped once started (default="
	41	__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
dfc7bd9c	42	#endif
853807fb AV	43
	44
	45	static unsigned long at91wdt_busy;
	46
	47	/* ......................................................................... */
	48
	49	/*
	50	* Disable the watchdog.
	51	*/
2760600d	52	static inline void at91_wdt_stop(void)
853807fb AV	53	{
	54	at91_sys_write(AT91_ST_WDMR, AT91_ST_EXTEN);
	55	}
	56
	57	/*
	58	* Enable and reset the watchdog.
	59	*/
2760600d	60	static inline void at91_wdt_start(void)
853807fb	61	{
2760600d AC	62	at91_sys_write(AT91_ST_WDMR, AT91_ST_EXTEN \| AT91_ST_RSTEN \|
2760600d AC	63	(((65536 * wdt_time) >> 8) & AT91_ST_WDV));
853807fb AV	64	at91_sys_write(AT91_ST_CR, AT91_ST_WDRST);
	65	}
	66
	67	/*
	68	* Reload the watchdog timer. (ie, pat the watchdog)
	69	*/
2760600d	70	static inline void at91_wdt_reload(void)
853807fb AV	71	{
	72	at91_sys_write(AT91_ST_CR, AT91_ST_WDRST);
	73	}
	74
	75	/* ......................................................................... */
	76
	77	/*
	78	* Watchdog device is opened, and watchdog starts running.
	79	*/
	80	static int at91_wdt_open(struct inode inode, struct file file)
	81	{
	82	if (test_and_set_bit(0, &at91wdt_busy))
	83	return -EBUSY;
	84
	85	at91_wdt_start();
	86	return nonseekable_open(inode, file);
	87	}
	88
	89	/*
	90	* Close the watchdog device.
	91	* If CONFIG_WATCHDOG_NOWAYOUT is NOT defined then the watchdog is also
	92	* disabled.
	93	*/
	94	static int at91_wdt_close(struct inode inode, struct file file)
	95	{
2760600d	96	/* Disable the watchdog when file is closed */
853807fb	97	if (!nowayout)
2760600d	98	at91_wdt_stop();
853807fb AV	99
	100	clear_bit(0, &at91wdt_busy);
	101	return 0;
	102	}
	103
	104	/*
	105	* Change the watchdog time interval.
	106	*/
	107	static int at91_wdt_settimeout(int new_time)
	108	{
	109	/*
2af29b78	110	* All counting occurs at SLOW_CLOCK / 128 = 256 Hz
853807fb AV	111	*
853807fb AV	112	* Since WDV is a 16-bit counter, the maximum period is
2af29b78	113	* 65536 / 256 = 256 seconds.
853807fb AV	114	*/
	115	if ((new_time <= 0) \|\| (new_time > WDT_MAX_TIME))
	116	return -EINVAL;
	117
2760600d AC	118	/* Set new watchdog time. It will be used when
2760600d AC	119	at91_wdt_start() is called. */
853807fb AV	120	wdt_time = new_time;
	121	return 0;
	122	}
	123
42747d71	124	static const struct watchdog_info at91_wdt_info = {
853807fb AV	125	.identity = "at91 watchdog",
	126	.options = WDIOF_SETTIMEOUT \| WDIOF_KEEPALIVEPING,
	127	};
	128
	129	/*
	130	* Handle commands from user-space.
	131	*/
3c4fafd6	132	static long at91_wdt_ioctl(struct file *file,
2760600d	133	unsigned int cmd, unsigned long arg)
853807fb AV	134	{
	135	void __user argp = (void __user )arg;
	136	int __user *p = argp;
	137	int new_value;
	138
2760600d	139	switch (cmd) {
2760600d AC	140	case WDIOC_GETSUPPORT:
	141	return copy_to_user(argp, &at91_wdt_info,
	142	sizeof(at91_wdt_info)) ? -EFAULT : 0;
2760600d AC	143	case WDIOC_GETSTATUS:
	144	case WDIOC_GETBOOTSTATUS:
	145	return put_user(0, p);
	146	case WDIOC_SETOPTIONS:
	147	if (get_user(new_value, p))
	148	return -EFAULT;
	149	if (new_value & WDIOS_DISABLECARD)
	150	at91_wdt_stop();
	151	if (new_value & WDIOS_ENABLECARD)
853807fb	152	at91_wdt_start();
2760600d	153	return 0;
0c06090c WVS	154	case WDIOC_KEEPALIVE:
	155	at91_wdt_reload(); /* pat the watchdog */
	156	return 0;
	157	case WDIOC_SETTIMEOUT:
	158	if (get_user(new_value, p))
	159	return -EFAULT;
	160	if (at91_wdt_settimeout(new_value))
	161	return -EINVAL;
	162	/* Enable new time value */
	163	at91_wdt_start();
	164	/* Return current value */
	165	return put_user(wdt_time, p);
	166	case WDIOC_GETTIMEOUT:
	167	return put_user(wdt_time, p);
2760600d AC	168	default:
2760600d AC	169	return -ENOTTY;
853807fb AV	170	}
	171	}
	172
	173	/*
	174	* Pat the watchdog whenever device is written to.
	175	*/
2760600d AC	176	static ssize_t at91_wdt_write(struct file file, const char data,
2760600d AC	177	size_t len, loff_t *ppos)
853807fb AV	178	{
	179	at91_wdt_reload(); /* pat the watchdog */
	180	return len;
	181	}
	182
	183	/* ......................................................................... */
	184
62322d25	185	static const struct file_operations at91wdt_fops = {
853807fb AV	186	.owner = THIS_MODULE,
853807fb AV	187	.llseek = no_llseek,
2760600d	188	.unlocked_ioctl = at91_wdt_ioctl,
853807fb AV	189	.open = at91_wdt_open,
	190	.release = at91_wdt_close,
	191	.write = at91_wdt_write,
	192	};
	193
	194	static struct miscdevice at91wdt_miscdev = {
	195	.minor = WATCHDOG_MINOR,
	196	.name = "watchdog",
	197	.fops = &at91wdt_fops,
	198	};
	199
47dec7c6	200	static int __devinit at91wdt_probe(struct platform_device *pdev)
853807fb AV	201	{
	202	int res;
	203
e0b79e0b	204	if (at91wdt_miscdev.parent)
dfc7bd9c	205	return -EBUSY;
e0b79e0b	206	at91wdt_miscdev.parent = &pdev->dev;
853807fb AV	207
	208	res = misc_register(&at91wdt_miscdev);
	209	if (res)
	210	return res;
	211
2760600d AC	212	printk(KERN_INFO "AT91 Watchdog Timer enabled (%d seconds%s)\n",
2760600d AC	213	wdt_time, nowayout ? ", nowayout" : "");
853807fb AV	214	return 0;
	215	}
	216
47dec7c6	217	static int __devexit at91wdt_remove(struct platform_device *pdev)
dfc7bd9c AV	218	{
	219	int res;
	220
	221	res = misc_deregister(&at91wdt_miscdev);
	222	if (!res)
e0b79e0b	223	at91wdt_miscdev.parent = NULL;
dfc7bd9c AV	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();
95f62bdc	245	return 0;
dfc7bd9c AV	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,
47dec7c6	255	.remove = __devexit_p(at91wdt_remove),
dfc7bd9c AV	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	{
2760600d AC	267	/* Check that the heartbeat value is within range;
2760600d AC	268	if not reset to the default */
dfc7bd9c AV	269	if (at91_wdt_settimeout(wdt_time)) {
dfc7bd9c AV	270	at91_wdt_settimeout(WDT_DEFAULT_TIME);
a77dba7e WVS	271	pr_info("at91_wdt: wdt_time value must be 1 <= wdt_time <= 256"
a77dba7e WVS	272	", using %d\n", wdt_time);
dfc7bd9c AV	273	}
	274
	275	return platform_driver_register(&at91wdt_driver);
	276	}
	277
853807fb AV	278	static void __exit at91_wdt_exit(void)
853807fb AV	279	{
dfc7bd9c	280	platform_driver_unregister(&at91wdt_driver);
853807fb AV	281	}
	282
	283	module_init(at91_wdt_init);
	284	module_exit(at91_wdt_exit);
	285
	286	MODULE_AUTHOR("Andrew Victor");
	287	MODULE_DESCRIPTION("Watchdog driver for Atmel AT91RM9200");
	288	MODULE_LICENSE("GPL");
	289	MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
f37d193c	290	MODULE_ALIAS("platform:at91_wdt");