[deliverable/linux.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/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>
#include <asm/arch/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 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 -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,
	.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("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);
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>
55d8baee	24	#include <asm/arch/at91_st.h>
853807fb AV	25
853807fb AV	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);
	34	MODULE_PARM_DESC(wdt_time, "Watchdog time in seconds. (default="__MODULE_STRING(WDT_DEFAULT_TIME) ")");
	35
dfc7bd9c	36	#ifdef CONFIG_WATCHDOG_NOWAYOUT
853807fb AV	37	module_param(nowayout, int, 0);
853807fb AV	38	MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
dfc7bd9c	39	#endif
853807fb AV	40
	41
	42	static unsigned long at91wdt_busy;
	43
	44	/* ......................................................................... */
	45
	46	/*
	47	* Disable the watchdog.
	48	*/
	49	static void inline at91_wdt_stop(void)
	50	{
	51	at91_sys_write(AT91_ST_WDMR, AT91_ST_EXTEN);
	52	}
	53
	54	/*
	55	* Enable and reset the watchdog.
	56	*/
	57	static void inline at91_wdt_start(void)
	58	{
	59	at91_sys_write(AT91_ST_WDMR, AT91_ST_EXTEN \| AT91_ST_RSTEN \| (((65536 * wdt_time) >> 8) & AT91_ST_WDV));
	60	at91_sys_write(AT91_ST_CR, AT91_ST_WDRST);
	61	}
	62
	63	/*
	64	* Reload the watchdog timer. (ie, pat the watchdog)
	65	*/
	66	static void inline at91_wdt_reload(void)
	67	{
	68	at91_sys_write(AT91_ST_CR, AT91_ST_WDRST);
	69	}
	70
	71	/* ......................................................................... */
	72
	73	/*
	74	* Watchdog device is opened, and watchdog starts running.
	75	*/
	76	static int at91_wdt_open(struct inode inode, struct file file)
	77	{
	78	if (test_and_set_bit(0, &at91wdt_busy))
	79	return -EBUSY;
	80
	81	at91_wdt_start();
	82	return nonseekable_open(inode, file);
	83	}
	84
	85	/*
	86	* Close the watchdog device.
	87	* If CONFIG_WATCHDOG_NOWAYOUT is NOT defined then the watchdog is also
	88	* disabled.
	89	*/
	90	static int at91_wdt_close(struct inode inode, struct file file)
	91	{
	92	if (!nowayout)
	93	at91_wdt_stop(); /* Disable the watchdog when file is closed */
	94
	95	clear_bit(0, &at91wdt_busy);
	96	return 0;
	97	}
	98
	99	/*
	100	* Change the watchdog time interval.
	101	*/
	102	static int at91_wdt_settimeout(int new_time)
	103	{
104	/*
105	* All counting occurs at SLOW_CLOCK / 128 = 0.256 Hz
106	*
107	* Since WDV is a 16-bit counter, the maximum period is
108	* 65536 / 0.256 = 256 seconds.
109	*/
110	if ((new_time <= 0) \|\| (new_time > WDT_MAX_TIME))
111	return -EINVAL;
112
113	/* Set new watchdog time. It will be used when at91_wdt_start() is called. */
114	wdt_time = new_time;
115	return 0;
116	}
117
118	static struct watchdog_info at91_wdt_info = {
119	.identity = "at91 watchdog",
120	.options = WDIOF_SETTIMEOUT \| WDIOF_KEEPALIVEPING,
121	};
122
123	/*
124	* Handle commands from user-space.
125	*/
126	static int at91_wdt_ioctl(struct inode inode, struct file file,
127	unsigned int cmd, unsigned long arg)
128	{
129	void __user argp = (void __user )arg;
130	int __user *p = argp;
131	int new_value;
132
133	switch(cmd) {
134	case WDIOC_KEEPALIVE:
135	at91_wdt_reload(); /* pat the watchdog */
136	return 0;
137
138	case WDIOC_GETSUPPORT:
139	return copy_to_user(argp, &at91_wdt_info, sizeof(at91_wdt_info)) ? -EFAULT : 0;
140
141	case WDIOC_SETTIMEOUT:
142	if (get_user(new_value, p))
143	return -EFAULT;
dfc7bd9c	144
853807fb AV	145	if (at91_wdt_settimeout(new_value))
	146	return -EINVAL;
	147
	148	/* Enable new time value */
	149	at91_wdt_start();
	150
	151	/* Return current value */
	152	return put_user(wdt_time, p);
	153
	154	case WDIOC_GETTIMEOUT:
	155	return put_user(wdt_time, p);
	156
	157	case WDIOC_GETSTATUS:
	158	case WDIOC_GETBOOTSTATUS:
	159	return put_user(0, p);
	160
	161	case WDIOC_SETOPTIONS:
	162	if (get_user(new_value, p))
	163	return -EFAULT;
	164
	165	if (new_value & WDIOS_DISABLECARD)
	166	at91_wdt_stop();
	167	if (new_value & WDIOS_ENABLECARD)
	168	at91_wdt_start();
	169	return 0;
	170
	171	default:
795b89d2	172	return -ENOTTY;
853807fb AV	173	}
	174	}
	175
	176	/*
	177	* Pat the watchdog whenever device is written to.
	178	*/
	179	static ssize_t at91_wdt_write(struct file file, const char data, size_t len, loff_t *ppos)
	180	{
	181	at91_wdt_reload(); /* pat the watchdog */
	182	return len;
	183	}
	184
	185	/* ......................................................................... */
	186
62322d25	187	static const struct file_operations at91wdt_fops = {
853807fb AV	188	.owner = THIS_MODULE,
	189	.llseek = no_llseek,
	190	.ioctl = at91_wdt_ioctl,
	191	.open = at91_wdt_open,
	192	.release = at91_wdt_close,
	193	.write = at91_wdt_write,
	194	};
	195
	196	static struct miscdevice at91wdt_miscdev = {
	197	.minor = WATCHDOG_MINOR,
	198	.name = "watchdog",
	199	.fops = &at91wdt_fops,
	200	};
	201
dfc7bd9c	202	static int __init at91wdt_probe(struct platform_device *pdev)
853807fb AV	203	{
	204	int res;
	205
e0b79e0b	206	if (at91wdt_miscdev.parent)
dfc7bd9c	207	return -EBUSY;
e0b79e0b	208	at91wdt_miscdev.parent = &pdev->dev;
853807fb AV	209
	210	res = misc_register(&at91wdt_miscdev);
	211	if (res)
	212	return res;
	213
dfc7bd9c	214	printk("AT91 Watchdog Timer enabled (%d seconds%s)\n", wdt_time, nowayout ? ", nowayout" : "");
853807fb AV	215	return 0;
	216	}
	217
dfc7bd9c AV	218	static int __exit at91wdt_remove(struct platform_device *pdev)
	219	{
	220	int res;
	221
	222	res = misc_deregister(&at91wdt_miscdev);
	223	if (!res)
e0b79e0b	224	at91wdt_miscdev.parent = NULL;
dfc7bd9c AV	225
	226	return res;
	227	}
	228
	229	static void at91wdt_shutdown(struct platform_device *pdev)
	230	{
	231	at91_wdt_stop();
	232	}
	233
	234	#ifdef CONFIG_PM
	235
	236	static int at91wdt_suspend(struct platform_device *pdev, pm_message_t message)
	237	{
	238	at91_wdt_stop();
	239	return 0;
	240	}
	241
	242	static int at91wdt_resume(struct platform_device *pdev)
	243	{
	244	if (at91wdt_busy)
	245	at91_wdt_start();
	246	return 0;
	247	}
	248
	249	#else
	250	#define at91wdt_suspend NULL
	251	#define at91wdt_resume NULL
	252	#endif
	253
	254	static struct platform_driver at91wdt_driver = {
	255	.probe = at91wdt_probe,
	256	.remove = __exit_p(at91wdt_remove),
	257	.shutdown = at91wdt_shutdown,
	258	.suspend = at91wdt_suspend,
	259	.resume = at91wdt_resume,
	260	.driver = {
	261	.name = "at91_wdt",
	262	.owner = THIS_MODULE,
	263	},
	264	};
	265
	266	static int __init at91_wdt_init(void)
	267	{
	268	/* Check that the heartbeat value is within range; if not reset to the default */
	269	if (at91_wdt_settimeout(wdt_time)) {
	270	at91_wdt_settimeout(WDT_DEFAULT_TIME);
	271	pr_info("at91_wdt: wdt_time value must be 1 <= wdt_time <= 256, using %d\n", wdt_time);
	272	}
	273
	274	return platform_driver_register(&at91wdt_driver);
	275	}
	276
853807fb AV	277	static void __exit at91_wdt_exit(void)
853807fb AV	278	{
dfc7bd9c	279	platform_driver_unregister(&at91wdt_driver);
853807fb AV	280	}
	281
	282	module_init(at91_wdt_init);
	283	module_exit(at91_wdt_exit);
	284
	285	MODULE_AUTHOR("Andrew Victor");
	286	MODULE_DESCRIPTION("Watchdog driver for Atmel AT91RM9200");
	287	MODULE_LICENSE("GPL");
	288	MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);