[linux-2.6-block.git] / drivers / watchdog / wdt285.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *	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.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#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/system_info.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)
{
	pr_crit("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
	stream_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)
{
	int __user *int_arg = (int __user *)arg;
	int new_margin, 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 through */
	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;

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

	if (machine_is_cats())
		pr_warn("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_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
2874c5fd	1	// SPDX-License-Identifier: GPL-2.0-or-later
1da177e4 LT	2	/*
	3	* Intel 21285 watchdog driver
	4	* Copyright (c) Phil Blundell <pb@nexus.co.uk>, 1998
	5	*
	6	* based on
	7	*
	8	* SoftDog 0.05: A Software Watchdog Device
	9	*
29fa0586 AC	10	* (c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>,
29fa0586 AC	11	* All Rights Reserved.
1da177e4 LT	12	*/
1da177e4 LT	13
27c766aa JP	14	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
27c766aa JP	15
1da177e4 LT	16	#include <linux/module.h>
	17	#include <linux/moduleparam.h>
	18	#include <linux/types.h>
	19	#include <linux/kernel.h>
	20	#include <linux/fs.h>
	21	#include <linux/mm.h>
	22	#include <linux/miscdevice.h>
	23	#include <linux/watchdog.h>
	24	#include <linux/reboot.h>
	25	#include <linux/init.h>
	26	#include <linux/interrupt.h>
d0e58eed AC	27	#include <linux/uaccess.h>
d0e58eed AC	28	#include <linux/irq.h>
a09e64fb	29	#include <mach/hardware.h>
1da177e4	30
1da177e4	31	#include <asm/mach-types.h>
9f97da78	32	#include <asm/system_info.h>
1da177e4 LT	33	#include <asm/hardware/dec21285.h>
	34
	35	/*
	36	* Define this to stop the watchdog actually rebooting the machine.
	37	*/
	38	#undef ONLY_TESTING
	39
	40	static unsigned int soft_margin = 60; /* in seconds */
	41	static unsigned int reload;
	42	static unsigned long timer_alive;
	43
	44	#ifdef ONLY_TESTING
	45	/*
	46	* If the timer expires..
	47	*/
7d12e780	48	static void watchdog_fire(int irq, void *dev_id)
1da177e4	49	{
27c766aa	50	pr_crit("Would Reboot\n");
1da177e4 LT	51	*CSR_TIMER4_CNTL = 0;
	52	*CSR_TIMER4_CLR = 0;
	53	}
	54	#endif
	55
	56	/*
	57	* Refresh the timer.
	58	*/
	59	static void watchdog_ping(void)
	60	{
	61	*CSR_TIMER4_LOAD = reload;
	62	}
	63
	64	/*
	65	* Allow only one person to hold it open
	66	*/
	67	static int watchdog_open(struct inode inode, struct file file)
	68	{
	69	int ret;
	70
	71	if (*CSR_SA110_CNTL & (1 << 13))
	72	return -EBUSY;
	73
	74	if (test_and_set_bit(1, &timer_alive))
	75	return -EBUSY;
	76
	77	reload = soft_margin * (mem_fclk_21285 / 256);
	78
	79	*CSR_TIMER4_CLR = 0;
	80	watchdog_ping();
	81	*CSR_TIMER4_CNTL = TIMER_CNTL_ENABLE \| TIMER_CNTL_AUTORELOAD
	82	\| TIMER_CNTL_DIV256;
	83
	84	#ifdef ONLY_TESTING
	85	ret = request_irq(IRQ_TIMER4, watchdog_fire, 0, "watchdog", NULL);
	86	if (ret) {
	87	*CSR_TIMER4_CNTL = 0;
	88	clear_bit(1, &timer_alive);
	89	}
	90	#else
	91	/*
	92	* Setting this bit is irreversible; once enabled, there is
	93	* no way to disable the watchdog.
	94	*/
	95	*CSR_SA110_CNTL \|= 1 << 13;
	96
	97	ret = 0;
	98	#endif
c5bf68fe	99	stream_open(inode, file);
1da177e4 LT	100	return ret;
	101	}
	102
	103	/*
	104	* Shut off the timer.
	105	* Note: if we really have enabled the watchdog, there
	106	* is no way to turn off.
	107	*/
	108	static int watchdog_release(struct inode inode, struct file file)
	109	{
	110	#ifdef ONLY_TESTING
	111	free_irq(IRQ_TIMER4, NULL);
	112	clear_bit(1, &timer_alive);
	113	#endif
	114	return 0;
	115	}
	116
edf86c9b BD	117	static ssize_t watchdog_write(struct file file, const char __user data,
edf86c9b BD	118	size_t len, loff_t *ppos)
1da177e4 LT	119	{
	120	/*
	121	* Refresh the timer.
	122	*/
	123	if (len)
	124	watchdog_ping();
	125
	126	return len;
	127	}
	128
d0e58eed	129	static const struct watchdog_info ident = {
1da177e4 LT	130	.options = WDIOF_SETTIMEOUT,
	131	.identity = "Footbridge Watchdog",
	132	};
	133
d0e58eed	134	static long watchdog_ioctl(struct file *file, unsigned int cmd,
edf86c9b	135	unsigned long arg)
1da177e4	136	{
edf86c9b	137	int __user int_arg = (int __user )arg;
70605d9b	138	int new_margin, ret = -ENOTTY;
1da177e4	139
d0e58eed	140	switch (cmd) {
1da177e4 LT	141	case WDIOC_GETSUPPORT:
1da177e4 LT	142	ret = 0;
edf86c9b	143	if (copy_to_user((void __user *)arg, &ident, sizeof(ident)))
1da177e4 LT	144	ret = -EFAULT;
	145	break;
	146
	147	case WDIOC_GETSTATUS:
	148	case WDIOC_GETBOOTSTATUS:
edf86c9b	149	ret = put_user(0, int_arg);
1da177e4 LT	150	break;
	151
	152	case WDIOC_KEEPALIVE:
	153	watchdog_ping();
	154	ret = 0;
	155	break;
	156
	157	case WDIOC_SETTIMEOUT:
edf86c9b	158	ret = get_user(new_margin, int_arg);
1da177e4 LT	159	if (ret)
	160	break;
	161
	162	/* Arbitrary, can't find the card's limits */
	163	if (new_margin < 0 \|\| new_margin > 60) {
	164	ret = -EINVAL;
	165	break;
	166	}
	167
	168	soft_margin = new_margin;
	169	reload = soft_margin * (mem_fclk_21285 / 256);
	170	watchdog_ping();
c9cbbb9f	171	/* Fall through */
1da177e4	172	case WDIOC_GETTIMEOUT:
edf86c9b	173	ret = put_user(soft_margin, int_arg);
1da177e4 LT	174	break;
	175	}
	176	return ret;
	177	}
	178
62322d25	179	static const struct file_operations watchdog_fops = {
1da177e4 LT	180	.owner = THIS_MODULE,
	181	.llseek = no_llseek,
	182	.write = watchdog_write,
d0e58eed	183	.unlocked_ioctl = watchdog_ioctl,
1da177e4 LT	184	.open = watchdog_open,
	185	.release = watchdog_release,
	186	};
	187
	188	static struct miscdevice watchdog_miscdev = {
	189	.minor = WATCHDOG_MINOR,
	190	.name = "watchdog",
	191	.fops = &watchdog_fops,
	192	};
	193
	194	static int __init footbridge_watchdog_init(void)
	195	{
	196	int retval;
	197
	198	if (machine_is_netwinder())
	199	return -ENODEV;
	200
	201	retval = misc_register(&watchdog_miscdev);
	202	if (retval < 0)
	203	return retval;
	204
27c766aa JP	205	pr_info("Footbridge Watchdog Timer: 0.01, timer margin: %d sec\n",
27c766aa JP	206	soft_margin);
1da177e4 LT	207
1da177e4 LT	208	if (machine_is_cats())
27c766aa	209	pr_warn("Warning: Watchdog reset may not work on this machine\n");
1da177e4 LT	210	return 0;
	211	}
	212
	213	static void __exit footbridge_watchdog_exit(void)
	214	{
	215	misc_deregister(&watchdog_miscdev);
	216	}
	217
	218	MODULE_AUTHOR("Phil Blundell <pb@nexus.co.uk>");
	219	MODULE_DESCRIPTION("Footbridge watchdog driver");
	220	MODULE_LICENSE("GPL");
1da177e4 LT	221
1da177e4 LT	222	module_param(soft_margin, int, 0);
d0e58eed	223	MODULE_PARM_DESC(soft_margin, "Watchdog timeout in seconds");
1da177e4 LT	224
	225	module_init(footbridge_watchdog_init);
	226	module_exit(footbridge_watchdog_exit);