[net-next-2.6.git] / drivers / watchdog / wdt285.c

/*
 *	Intel 21285 watchdog driver
 *	Copyright (c) Phil Blundell <pb@nexus.co.uk>, 1998
 *
 *	based on
 *
 *	SoftDog	0.05:	A Software Watchdog Device
 *
 *	(c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>,
 *						All Rights Reserved.
 *
 *	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/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/reboot.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/uaccess.h>
#include <linux/irq.h>
#include <mach/hardware.h>

#include <asm/mach-types.h>
#include <asm/hardware/dec21285.h>

/*
 * Define this to stop the watchdog actually rebooting the machine.
 */
#undef ONLY_TESTING

static unsigned int soft_margin = 60;		/* in seconds */
static unsigned int reload;
static unsigned long timer_alive;

#ifdef ONLY_TESTING
/*
 *	If the timer expires..
 */
static void watchdog_fire(int irq, void *dev_id)
{
	printk(KERN_CRIT "Watchdog: Would Reboot.\n");
	*CSR_TIMER4_CNTL = 0;
	*CSR_TIMER4_CLR = 0;
}
#endif

/*
 *	Refresh the timer.
 */
static void watchdog_ping(void)
{
	*CSR_TIMER4_LOAD = reload;
}

/*
 *	Allow only one person to hold it open
 */
static int watchdog_open(struct inode *inode, struct file *file)
{
	int ret;

	if (*CSR_SA110_CNTL & (1 << 13))
		return -EBUSY;

	if (test_and_set_bit(1, &timer_alive))
		return -EBUSY;

	reload = soft_margin * (mem_fclk_21285 / 256);

	*CSR_TIMER4_CLR = 0;
	watchdog_ping();
	*CSR_TIMER4_CNTL = TIMER_CNTL_ENABLE | TIMER_CNTL_AUTORELOAD
		| TIMER_CNTL_DIV256;

#ifdef ONLY_TESTING
	ret = request_irq(IRQ_TIMER4, watchdog_fire, 0, "watchdog", NULL);
	if (ret) {
		*CSR_TIMER4_CNTL = 0;
		clear_bit(1, &timer_alive);
	}
#else
	/*
	 * Setting this bit is irreversible; once enabled, there is
	 * no way to disable the watchdog.
	 */
	*CSR_SA110_CNTL |= 1 << 13;

	ret = 0;
#endif
	nonseekable_open(inode, file);
	return ret;
}

/*
 *	Shut off the timer.
 *	Note: if we really have enabled the watchdog, there
 *	is no way to turn off.
 */
static int watchdog_release(struct inode *inode, struct file *file)
{
#ifdef ONLY_TESTING
	free_irq(IRQ_TIMER4, NULL);
	clear_bit(1, &timer_alive);
#endif
	return 0;
}

static ssize_t watchdog_write(struct file *file, const char __user *data,
			      size_t len, loff_t *ppos)
{
	/*
	 *	Refresh the timer.
	 */
	if (len)
		watchdog_ping();

	return len;
}

static const struct watchdog_info ident = {
	.options	= WDIOF_SETTIMEOUT,
	.identity	= "Footbridge Watchdog",
};

static long watchdog_ioctl(struct file *file, unsigned int cmd,
			   unsigned long arg)
{
	unsigned int new_margin;
	int __user *int_arg = (int __user *)arg;
	int ret = -ENOTTY;

	switch (cmd) {
	case WDIOC_GETSUPPORT:
		ret = 0;
		if (copy_to_user((void __user *)arg, &ident, sizeof(ident)))
			ret = -EFAULT;
		break;

	case WDIOC_GETSTATUS:
	case WDIOC_GETBOOTSTATUS:
		ret = put_user(0, int_arg);
		break;

	case WDIOC_KEEPALIVE:
		watchdog_ping();
		ret = 0;
		break;

	case WDIOC_SETTIMEOUT:
		ret = get_user(new_margin, int_arg);
		if (ret)
			break;

		/* Arbitrary, can't find the card's limits */
		if (new_margin < 0 || new_margin > 60) {
			ret = -EINVAL;
			break;
		}

		soft_margin = new_margin;
		reload = soft_margin * (mem_fclk_21285 / 256);
		watchdog_ping();
		/* Fall */
	case WDIOC_GETTIMEOUT:
		ret = put_user(soft_margin, int_arg);
		break;
	}
	return ret;
}

static const struct file_operations watchdog_fops = {
	.owner		= THIS_MODULE,
	.llseek		= no_llseek,
	.write		= watchdog_write,
	.unlocked_ioctl	= watchdog_ioctl,
	.open		= watchdog_open,
	.release	= watchdog_release,
};

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

static int __init footbridge_watchdog_init(void)
{
	int retval;

	if (machine_is_netwinder())
		return -ENODEV;

	retval = misc_register(&watchdog_miscdev);
	if (retval < 0)
		return retval;

	printk(KERN_INFO
		"Footbridge Watchdog Timer: 0.01, timer margin: %d sec\n",
								soft_margin);

	if (machine_is_cats())
		printk(KERN_WARNING
		  "Warning: Watchdog reset may not work on this machine.\n");
	return 0;
}

static void __exit footbridge_watchdog_exit(void)
{
	misc_deregister(&watchdog_miscdev);
}

MODULE_AUTHOR("Phil Blundell <pb@nexus.co.uk>");
MODULE_DESCRIPTION("Footbridge watchdog driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);

module_param(soft_margin, int, 0);
MODULE_PARM_DESC(soft_margin, "Watchdog timeout in seconds");

module_init(footbridge_watchdog_init);
module_exit(footbridge_watchdog_exit);
Commit	Line	Data
1da177e4 LT	1	/*
	2	* Intel 21285 watchdog driver
	3	* Copyright (c) Phil Blundell <pb@nexus.co.uk>, 1998
	4	*
	5	* based on
	6	*
	7	* SoftDog 0.05: A Software Watchdog Device
	8	*
29fa0586 AC	9	* (c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>,
29fa0586 AC	10	* All Rights Reserved.
1da177e4 LT	11	*
	12	* This program is free software; you can redistribute it and/or
	13	* modify it under the terms of the GNU General Public License
	14	* as published by the Free Software Foundation; either version
	15	* 2 of the License, or (at your option) any later version.
	16	*
	17	*/
	18
	19	#include <linux/module.h>
	20	#include <linux/moduleparam.h>
	21	#include <linux/types.h>
	22	#include <linux/kernel.h>
	23	#include <linux/fs.h>
	24	#include <linux/mm.h>
	25	#include <linux/miscdevice.h>
	26	#include <linux/watchdog.h>
	27	#include <linux/reboot.h>
	28	#include <linux/init.h>
	29	#include <linux/interrupt.h>
d0e58eed AC	30	#include <linux/uaccess.h>
d0e58eed AC	31	#include <linux/irq.h>
a09e64fb	32	#include <mach/hardware.h>
1da177e4	33
1da177e4 LT	34	#include <asm/mach-types.h>
	35	#include <asm/hardware/dec21285.h>
	36
	37	/*
	38	* Define this to stop the watchdog actually rebooting the machine.
	39	*/
	40	#undef ONLY_TESTING
	41
	42	static unsigned int soft_margin = 60; /* in seconds */
	43	static unsigned int reload;
	44	static unsigned long timer_alive;
	45
	46	#ifdef ONLY_TESTING
	47	/*
	48	* If the timer expires..
	49	*/
7d12e780	50	static void watchdog_fire(int irq, void *dev_id)
1da177e4 LT	51	{
	52	printk(KERN_CRIT "Watchdog: Would Reboot.\n");
	53	*CSR_TIMER4_CNTL = 0;
	54	*CSR_TIMER4_CLR = 0;
	55	}
	56	#endif
	57
	58	/*
	59	* Refresh the timer.
	60	*/
	61	static void watchdog_ping(void)
	62	{
	63	*CSR_TIMER4_LOAD = reload;
	64	}
	65
	66	/*
	67	* Allow only one person to hold it open
	68	*/
	69	static int watchdog_open(struct inode inode, struct file file)
	70	{
	71	int ret;
	72
	73	if (*CSR_SA110_CNTL & (1 << 13))
	74	return -EBUSY;
	75
	76	if (test_and_set_bit(1, &timer_alive))
	77	return -EBUSY;
	78
	79	reload = soft_margin * (mem_fclk_21285 / 256);
	80
	81	*CSR_TIMER4_CLR = 0;
	82	watchdog_ping();
	83	*CSR_TIMER4_CNTL = TIMER_CNTL_ENABLE \| TIMER_CNTL_AUTORELOAD
	84	\| TIMER_CNTL_DIV256;
	85
	86	#ifdef ONLY_TESTING
	87	ret = request_irq(IRQ_TIMER4, watchdog_fire, 0, "watchdog", NULL);
	88	if (ret) {
	89	*CSR_TIMER4_CNTL = 0;
	90	clear_bit(1, &timer_alive);
	91	}
	92	#else
	93	/*
	94	* Setting this bit is irreversible; once enabled, there is
	95	* no way to disable the watchdog.
	96	*/
	97	*CSR_SA110_CNTL \|= 1 << 13;
	98
	99	ret = 0;
	100	#endif
	101	nonseekable_open(inode, file);
	102	return ret;
	103	}
	104
	105	/*
	106	* Shut off the timer.
	107	* Note: if we really have enabled the watchdog, there
	108	* is no way to turn off.
	109	*/
	110	static int watchdog_release(struct inode inode, struct file file)
	111	{
	112	#ifdef ONLY_TESTING
	113	free_irq(IRQ_TIMER4, NULL);
	114	clear_bit(1, &timer_alive);
115	#endif
116	return 0;
117	}
118
edf86c9b BD	119	static ssize_t watchdog_write(struct file file, const char __user data,
edf86c9b BD	120	size_t len, loff_t *ppos)
1da177e4 LT	121	{
	122	/*
	123	* Refresh the timer.
	124	*/
	125	if (len)
	126	watchdog_ping();
	127
	128	return len;
	129	}
	130
d0e58eed	131	static const struct watchdog_info ident = {
1da177e4 LT	132	.options = WDIOF_SETTIMEOUT,
	133	.identity = "Footbridge Watchdog",
	134	};
	135
d0e58eed	136	static long watchdog_ioctl(struct file *file, unsigned int cmd,
edf86c9b	137	unsigned long arg)
1da177e4 LT	138	{
1da177e4 LT	139	unsigned int new_margin;
edf86c9b	140	int __user int_arg = (int __user )arg;
795b89d2	141	int ret = -ENOTTY;
1da177e4	142
d0e58eed	143	switch (cmd) {
1da177e4 LT	144	case WDIOC_GETSUPPORT:
1da177e4 LT	145	ret = 0;
edf86c9b	146	if (copy_to_user((void __user *)arg, &ident, sizeof(ident)))
1da177e4 LT	147	ret = -EFAULT;
	148	break;
	149
	150	case WDIOC_GETSTATUS:
	151	case WDIOC_GETBOOTSTATUS:
edf86c9b	152	ret = put_user(0, int_arg);
1da177e4 LT	153	break;
	154
	155	case WDIOC_KEEPALIVE:
	156	watchdog_ping();
	157	ret = 0;
	158	break;
	159
	160	case WDIOC_SETTIMEOUT:
edf86c9b	161	ret = get_user(new_margin, int_arg);
1da177e4 LT	162	if (ret)
	163	break;
	164
	165	/* Arbitrary, can't find the card's limits */
	166	if (new_margin < 0 \|\| new_margin > 60) {
	167	ret = -EINVAL;
	168	break;
	169	}
	170
	171	soft_margin = new_margin;
	172	reload = soft_margin * (mem_fclk_21285 / 256);
	173	watchdog_ping();
	174	/* Fall */
	175	case WDIOC_GETTIMEOUT:
edf86c9b	176	ret = put_user(soft_margin, int_arg);
1da177e4 LT	177	break;
	178	}
	179	return ret;
	180	}
	181
62322d25	182	static const struct file_operations watchdog_fops = {
1da177e4 LT	183	.owner = THIS_MODULE,
	184	.llseek = no_llseek,
	185	.write = watchdog_write,
d0e58eed	186	.unlocked_ioctl = watchdog_ioctl,
1da177e4 LT	187	.open = watchdog_open,
	188	.release = watchdog_release,
	189	};
	190
	191	static struct miscdevice watchdog_miscdev = {
	192	.minor = WATCHDOG_MINOR,
	193	.name = "watchdog",
	194	.fops = &watchdog_fops,
	195	};
	196
	197	static int __init footbridge_watchdog_init(void)
	198	{
	199	int retval;
	200
	201	if (machine_is_netwinder())
	202	return -ENODEV;
	203
	204	retval = misc_register(&watchdog_miscdev);
	205	if (retval < 0)
	206	return retval;
	207
d0e58eed AC	208	printk(KERN_INFO
	209	"Footbridge Watchdog Timer: 0.01, timer margin: %d sec\n",
	210	soft_margin);
1da177e4 LT	211
1da177e4 LT	212	if (machine_is_cats())
3f11df21	213	printk(KERN_WARNING
d0e58eed	214	"Warning: Watchdog reset may not work on this machine.\n");
1da177e4 LT	215	return 0;
	216	}
	217
	218	static void __exit footbridge_watchdog_exit(void)
	219	{
	220	misc_deregister(&watchdog_miscdev);
	221	}
	222
	223	MODULE_AUTHOR("Phil Blundell <pb@nexus.co.uk>");
	224	MODULE_DESCRIPTION("Footbridge watchdog driver");
	225	MODULE_LICENSE("GPL");
	226	MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
	227
	228	module_param(soft_margin, int, 0);
d0e58eed	229	MODULE_PARM_DESC(soft_margin, "Watchdog timeout in seconds");
1da177e4 LT	230
	231	module_init(footbridge_watchdog_init);
	232	module_exit(footbridge_watchdog_exit);