[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/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 = 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 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 __init 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 __exit 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		= __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);
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>
	16	#include <linux/kernel.h>
	17	#include <linux/miscdevice.h>
	18	#include <linux/module.h>
	19	#include <linux/moduleparam.h>
dfc7bd9c	20	#include <linux/platform_device.h>
853807fb AV	21	#include <linux/types.h>
853807fb AV	22	#include <linux/watchdog.h>
2760600d	23	#include <linux/uaccess.h>
a09e64fb	24	#include <mach/at91_st.h>
853807fb	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);
2760600d AC	33	MODULE_PARM_DESC(wdt_time, "Watchdog time in seconds. (default="
2760600d AC	34	__MODULE_STRING(WDT_DEFAULT_TIME) ")");
853807fb	35
dfc7bd9c	36	#ifdef CONFIG_WATCHDOG_NOWAYOUT
853807fb	37	module_param(nowayout, int, 0);
2760600d AC	38	MODULE_PARM_DESC(nowayout,
	39	"Watchdog cannot be stopped once started (default="
	40	__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
dfc7bd9c	41	#endif
853807fb AV	42
	43
	44	static unsigned long at91wdt_busy;
	45
	46	/* ......................................................................... */
	47
	48	/*
	49	* Disable the watchdog.
	50	*/
2760600d	51	static inline void at91_wdt_stop(void)
853807fb AV	52	{
	53	at91_sys_write(AT91_ST_WDMR, AT91_ST_EXTEN);
	54	}
	55
	56	/*
	57	* Enable and reset the watchdog.
	58	*/
2760600d	59	static inline void at91_wdt_start(void)
853807fb	60	{
2760600d AC	61	at91_sys_write(AT91_ST_WDMR, AT91_ST_EXTEN \| AT91_ST_RSTEN \|
2760600d AC	62	(((65536 * wdt_time) >> 8) & AT91_ST_WDV));
853807fb AV	63	at91_sys_write(AT91_ST_CR, AT91_ST_WDRST);
	64	}
	65
	66	/*
	67	* Reload the watchdog timer. (ie, pat the watchdog)
	68	*/
2760600d	69	static inline void at91_wdt_reload(void)
853807fb AV	70	{
	71	at91_sys_write(AT91_ST_CR, AT91_ST_WDRST);
	72	}
	73
	74	/* ......................................................................... */
	75
	76	/*
	77	* Watchdog device is opened, and watchdog starts running.
	78	*/
	79	static int at91_wdt_open(struct inode inode, struct file file)
	80	{
	81	if (test_and_set_bit(0, &at91wdt_busy))
	82	return -EBUSY;
	83
	84	at91_wdt_start();
	85	return nonseekable_open(inode, file);
	86	}
	87
	88	/*
	89	* Close the watchdog device.
	90	* If CONFIG_WATCHDOG_NOWAYOUT is NOT defined then the watchdog is also
	91	* disabled.
	92	*/
	93	static int at91_wdt_close(struct inode inode, struct file file)
	94	{
2760600d	95	/* Disable the watchdog when file is closed */
853807fb	96	if (!nowayout)
2760600d	97	at91_wdt_stop();
853807fb AV	98
	99	clear_bit(0, &at91wdt_busy);
	100	return 0;
	101	}
	102
	103	/*
	104	* Change the watchdog time interval.
	105	*/
	106	static int at91_wdt_settimeout(int new_time)
	107	{
	108	/*
	109	* All counting occurs at SLOW_CLOCK / 128 = 0.256 Hz
	110	*
	111	* Since WDV is a 16-bit counter, the maximum period is
	112	* 65536 / 0.256 = 256 seconds.
	113	*/
	114	if ((new_time <= 0) \|\| (new_time > WDT_MAX_TIME))
	115	return -EINVAL;
	116
2760600d AC	117	/* Set new watchdog time. It will be used when
2760600d AC	118	at91_wdt_start() is called. */
853807fb AV	119	wdt_time = new_time;
	120	return 0;
	121	}
	122
	123	static struct watchdog_info at91_wdt_info = {
	124	.identity = "at91 watchdog",
	125	.options = WDIOF_SETTIMEOUT \| WDIOF_KEEPALIVEPING,
	126	};
	127
	128	/*
	129	* Handle commands from user-space.
	130	*/
3c4fafd6	131	static long at91_wdt_ioctl(struct file *file,
2760600d	132	unsigned int cmd, unsigned long arg)
853807fb AV	133	{
	134	void __user argp = (void __user )arg;
	135	int __user *p = argp;
	136	int new_value;
	137
2760600d	138	switch (cmd) {
2760600d AC	139	case WDIOC_GETSUPPORT:
	140	return copy_to_user(argp, &at91_wdt_info,
	141	sizeof(at91_wdt_info)) ? -EFAULT : 0;
2760600d AC	142	case WDIOC_GETSTATUS:
	143	case WDIOC_GETBOOTSTATUS:
	144	return put_user(0, p);
	145	case WDIOC_SETOPTIONS:
	146	if (get_user(new_value, p))
	147	return -EFAULT;
	148	if (new_value & WDIOS_DISABLECARD)
	149	at91_wdt_stop();
	150	if (new_value & WDIOS_ENABLECARD)
853807fb	151	at91_wdt_start();
2760600d	152	return 0;
0c06090c WVS	153	case WDIOC_KEEPALIVE:
	154	at91_wdt_reload(); /* pat the watchdog */
	155	return 0;
	156	case WDIOC_SETTIMEOUT:
	157	if (get_user(new_value, p))
	158	return -EFAULT;
	159	if (at91_wdt_settimeout(new_value))
	160	return -EINVAL;
	161	/* Enable new time value */
	162	at91_wdt_start();
	163	/* Return current value */
	164	return put_user(wdt_time, p);
	165	case WDIOC_GETTIMEOUT:
	166	return put_user(wdt_time, p);
2760600d AC	167	default:
2760600d AC	168	return -ENOTTY;
853807fb AV	169	}
	170	}
	171
	172	/*
	173	* Pat the watchdog whenever device is written to.
	174	*/
2760600d AC	175	static ssize_t at91_wdt_write(struct file file, const char data,
2760600d AC	176	size_t len, loff_t *ppos)
853807fb AV	177	{
	178	at91_wdt_reload(); /* pat the watchdog */
	179	return len;
	180	}
	181
	182	/* ......................................................................... */
	183
62322d25	184	static const struct file_operations at91wdt_fops = {
853807fb AV	185	.owner = THIS_MODULE,
853807fb AV	186	.llseek = no_llseek,
2760600d	187	.unlocked_ioctl = at91_wdt_ioctl,
853807fb AV	188	.open = at91_wdt_open,
	189	.release = at91_wdt_close,
	190	.write = at91_wdt_write,
	191	};
	192
	193	static struct miscdevice at91wdt_miscdev = {
	194	.minor = WATCHDOG_MINOR,
	195	.name = "watchdog",
	196	.fops = &at91wdt_fops,
	197	};
	198
dfc7bd9c	199	static int __init at91wdt_probe(struct platform_device *pdev)
853807fb AV	200	{
	201	int res;
	202
e0b79e0b	203	if (at91wdt_miscdev.parent)
dfc7bd9c	204	return -EBUSY;
e0b79e0b	205	at91wdt_miscdev.parent = &pdev->dev;
853807fb AV	206
	207	res = misc_register(&at91wdt_miscdev);
	208	if (res)
	209	return res;
	210
2760600d AC	211	printk(KERN_INFO "AT91 Watchdog Timer enabled (%d seconds%s)\n",
2760600d AC	212	wdt_time, nowayout ? ", nowayout" : "");
853807fb AV	213	return 0;
	214	}
	215
dfc7bd9c AV	216	static int __exit at91wdt_remove(struct platform_device *pdev)
	217	{
	218	int res;
	219
	220	res = misc_deregister(&at91wdt_miscdev);
	221	if (!res)
e0b79e0b	222	at91wdt_miscdev.parent = NULL;
dfc7bd9c AV	223
	224	return res;
	225	}
	226
	227	static void at91wdt_shutdown(struct platform_device *pdev)
	228	{
	229	at91_wdt_stop();
	230	}
	231
	232	#ifdef CONFIG_PM
	233
	234	static int at91wdt_suspend(struct platform_device *pdev, pm_message_t message)
	235	{
	236	at91_wdt_stop();
	237	return 0;
	238	}
	239
	240	static int at91wdt_resume(struct platform_device *pdev)
	241	{
	242	if (at91wdt_busy)
	243	at91_wdt_start();
	244	return 0;
	245	}
	246
	247	#else
	248	#define at91wdt_suspend NULL
	249	#define at91wdt_resume NULL
	250	#endif
	251
	252	static struct platform_driver at91wdt_driver = {
	253	.probe = at91wdt_probe,
	254	.remove = __exit_p(at91wdt_remove),
	255	.shutdown = at91wdt_shutdown,
	256	.suspend = at91wdt_suspend,
	257	.resume = at91wdt_resume,
	258	.driver = {
	259	.name = "at91_wdt",
	260	.owner = THIS_MODULE,
	261	},
	262	};
	263
	264	static int __init at91_wdt_init(void)
	265	{
2760600d AC	266	/* Check that the heartbeat value is within range;
2760600d AC	267	if not reset to the default */
dfc7bd9c AV	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);
f37d193c	288	MODULE_ALIAS("platform:at91_wdt");