[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@redhat.com>, 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 *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 ret = -ENOTTY;

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