[deliverable/linux.git] / drivers / watchdog / indydog.c

/*
 *	IndyDog	0.3	A Hardware Watchdog Device for SGI IP22
 *
 *	(c) Copyright 2002 Guido Guenther <agx@sigxcpu.org>,
 *						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.
 *
 *	based on softdog.c by Alan Cox <alan@lxorguk.ukuu.org.uk>
 */

#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/notifier.h>
#include <linux/reboot.h>
#include <linux/init.h>
#include <linux/uaccess.h>
#include <asm/sgi/mc.h>

#define PFX "indydog: "
static unsigned long indydog_alive;
static spinlock_t indydog_lock;

#define WATCHDOG_TIMEOUT 30		/* 30 sec default timeout */

static int nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, int, 0);
MODULE_PARM_DESC(nowayout,
		"Watchdog cannot be stopped once started (default="
				__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");

static void indydog_start(void)
{
	u32 mc_ctrl0;

	spin_lock(&indydog_lock);
	mc_ctrl0 = sgimc->cpuctrl0;
	mc_ctrl0 = sgimc->cpuctrl0 | SGIMC_CCTRL0_WDOG;
	sgimc->cpuctrl0 = mc_ctrl0;
	spin_unlock(&indydog_lock);
}

static void indydog_stop(void)
{
	u32 mc_ctrl0;

	spin_lock(&indydog_lock);

	mc_ctrl0 = sgimc->cpuctrl0;
	mc_ctrl0 &= ~SGIMC_CCTRL0_WDOG;
	sgimc->cpuctrl0 = mc_ctrl0;
	spin_unlock(&indydog_lock);

	printk(KERN_INFO PFX "Stopped watchdog timer.\n");
}

static void indydog_ping(void)
{
	sgimc->watchdogt = 0;
}

/*
 *	Allow only one person to hold it open
 */
static int indydog_open(struct inode *inode, struct file *file)
{
	if (test_and_set_bit(0, &indydog_alive))
		return -EBUSY;

	if (nowayout)
		__module_get(THIS_MODULE);

	/* Activate timer */
	indydog_start();
	indydog_ping();

	indydog_alive = 1;
	printk(KERN_INFO "Started watchdog timer.\n");

	return nonseekable_open(inode, file);
}

static int indydog_release(struct inode *inode, struct file *file)
{
	/* Shut off the timer.
	 * Lock it in if it's a module and we defined ...NOWAYOUT */
	if (!nowayout)
		indydog_stop();		/* Turn the WDT off */
	clear_bit(0, &indydog_alive);
	return 0;
}

static ssize_t indydog_write(struct file *file, const char *data,
						size_t len, loff_t *ppos)
{
	/* Refresh the timer. */
	if (len)
		indydog_ping();
	return len;
}

static long indydog_ioctl(struct file *file, unsigned int cmd,
							unsigned long arg)
{
	int options, retval = -EINVAL;
	static struct watchdog_info ident = {
		.options		= WDIOF_KEEPALIVEPING |
					  WDIOF_MAGICCLOSE,
		.firmware_version	= 0,
		.identity		= "Hardware Watchdog for SGI IP22",
	};

	switch (cmd) {
	case WDIOC_GETSUPPORT:
		if (copy_to_user((struct watchdog_info *)arg,
				 &ident, sizeof(ident)))
			return -EFAULT;
		return 0;
	case WDIOC_GETSTATUS:
	case WDIOC_GETBOOTSTATUS:
		return put_user(0, (int *)arg);
	case WDIOC_SETOPTIONS:
	{
		if (get_user(options, (int *)arg))
			return -EFAULT;
		if (options & WDIOS_DISABLECARD) {
			indydog_stop();
			retval = 0;
		}
		if (options & WDIOS_ENABLECARD) {
			indydog_start();
			retval = 0;
		}
		return retval;
	}
	case WDIOC_KEEPALIVE:
		indydog_ping();
		return 0;
	case WDIOC_GETTIMEOUT:
		return put_user(WATCHDOG_TIMEOUT, (int *)arg);
	default:
		return -ENOTTY;
	}
}

static int indydog_notify_sys(struct notifier_block *this,
					unsigned long code, void *unused)
{
	if (code == SYS_DOWN || code == SYS_HALT)
		indydog_stop();		/* Turn the WDT off */

	return NOTIFY_DONE;
}

static const struct file_operations indydog_fops = {
	.owner		= THIS_MODULE,
	.llseek		= no_llseek,
	.write		= indydog_write,
	.unlocked_ioctl	= indydog_ioctl,
	.open		= indydog_open,
	.release	= indydog_release,
};

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

static struct notifier_block indydog_notifier = {
	.notifier_call = indydog_notify_sys,
};

static char banner[] __initdata =
	KERN_INFO PFX "Hardware Watchdog Timer for SGI IP22: 0.3\n";

static int __init watchdog_init(void)
{
	int ret;

	spin_lock_init(&indydog_lock);

	ret = register_reboot_notifier(&indydog_notifier);
	if (ret) {
		printk(KERN_ERR PFX
			"cannot register reboot notifier (err=%d)\n", ret);
		return ret;
	}

	ret = misc_register(&indydog_miscdev);
	if (ret) {
		printk(KERN_ERR PFX
			"cannot register miscdev on minor=%d (err=%d)\n",
							WATCHDOG_MINOR, ret);
		unregister_reboot_notifier(&indydog_notifier);
		return ret;
	}

	printk(banner);

	return 0;
}

static void __exit watchdog_exit(void)
{
	misc_deregister(&indydog_miscdev);
	unregister_reboot_notifier(&indydog_notifier);
}

module_init(watchdog_init);
module_exit(watchdog_exit);

MODULE_AUTHOR("Guido Guenther <agx@sigxcpu.org>");
MODULE_DESCRIPTION("Hardware Watchdog Device for SGI IP22");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
Commit	Line	Data
1da177e4 LT	1	/*
	2	* IndyDog 0.3 A Hardware Watchdog Device for SGI IP22
	3	*
9b9dbcca AC	4	* (c) Copyright 2002 Guido Guenther <agx@sigxcpu.org>,
9b9dbcca AC	5	* All Rights Reserved.
1da177e4 LT	6	*
	7	* This program is free software; you can redistribute it and/or
	8	* modify it under the terms of the GNU General Public License
	9	* as published by the Free Software Foundation; either version
	10	* 2 of the License, or (at your option) any later version.
	11	*
29fa0586	12	* based on softdog.c by Alan Cox <alan@lxorguk.ukuu.org.uk>
1da177e4 LT	13	*/
	14
	15	#include <linux/module.h>
	16	#include <linux/moduleparam.h>
1da177e4 LT	17	#include <linux/types.h>
	18	#include <linux/kernel.h>
	19	#include <linux/fs.h>
	20	#include <linux/mm.h>
	21	#include <linux/miscdevice.h>
	22	#include <linux/watchdog.h>
	23	#include <linux/notifier.h>
	24	#include <linux/reboot.h>
	25	#include <linux/init.h>
9b9dbcca	26	#include <linux/uaccess.h>
1da177e4 LT	27	#include <asm/sgi/mc.h>
	28
	29	#define PFX "indydog: "
9b9dbcca AC	30	static unsigned long indydog_alive;
9b9dbcca AC	31	static spinlock_t indydog_lock;
1da177e4	32
1da177e4 LT	33	#define WATCHDOG_TIMEOUT 30 /* 30 sec default timeout */
1da177e4 LT	34
4bfdf378	35	static int nowayout = WATCHDOG_NOWAYOUT;
1da177e4	36	module_param(nowayout, int, 0);
9b9dbcca AC	37	MODULE_PARM_DESC(nowayout,
	38	"Watchdog cannot be stopped once started (default="
	39	__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
1da177e4 LT	40
	41	static void indydog_start(void)
	42	{
9b9dbcca	43	u32 mc_ctrl0;
1da177e4	44
9b9dbcca AC	45	spin_lock(&indydog_lock);
9b9dbcca AC	46	mc_ctrl0 = sgimc->cpuctrl0;
1da177e4 LT	47	mc_ctrl0 = sgimc->cpuctrl0 \| SGIMC_CCTRL0_WDOG;
1da177e4 LT	48	sgimc->cpuctrl0 = mc_ctrl0;
9b9dbcca	49	spin_unlock(&indydog_lock);
1da177e4 LT	50	}
	51
	52	static void indydog_stop(void)
	53	{
9b9dbcca	54	u32 mc_ctrl0;
1da177e4	55
9b9dbcca AC	56	spin_lock(&indydog_lock);
	57
	58	mc_ctrl0 = sgimc->cpuctrl0;
1da177e4 LT	59	mc_ctrl0 &= ~SGIMC_CCTRL0_WDOG;
1da177e4 LT	60	sgimc->cpuctrl0 = mc_ctrl0;
9b9dbcca	61	spin_unlock(&indydog_lock);
1da177e4 LT	62
	63	printk(KERN_INFO PFX "Stopped watchdog timer.\n");
	64	}
	65
	66	static void indydog_ping(void)
	67	{
	68	sgimc->watchdogt = 0;
	69	}
	70
	71	/*
	72	* Allow only one person to hold it open
	73	*/
	74	static int indydog_open(struct inode inode, struct file file)
	75	{
9b9dbcca	76	if (test_and_set_bit(0, &indydog_alive))
1da177e4 LT	77	return -EBUSY;
	78
	79	if (nowayout)
	80	__module_get(THIS_MODULE);
	81
	82	/* Activate timer */
	83	indydog_start();
	84	indydog_ping();
	85
	86	indydog_alive = 1;
	87	printk(KERN_INFO "Started watchdog timer.\n");
	88
	89	return nonseekable_open(inode, file);
	90	}
	91
	92	static int indydog_release(struct inode inode, struct file file)
	93	{
	94	/* Shut off the timer.
	95	* Lock it in if it's a module and we defined ...NOWAYOUT */
	96	if (!nowayout)
	97	indydog_stop(); /* Turn the WDT off */
9b9dbcca	98	clear_bit(0, &indydog_alive);
1da177e4 LT	99	return 0;
	100	}
	101
9b9dbcca AC	102	static ssize_t indydog_write(struct file file, const char data,
9b9dbcca AC	103	size_t len, loff_t *ppos)
1da177e4 LT	104	{
1da177e4 LT	105	/* Refresh the timer. */
9b9dbcca	106	if (len)
1da177e4	107	indydog_ping();
1da177e4 LT	108	return len;
	109	}
	110
9b9dbcca AC	111	static long indydog_ioctl(struct file *file, unsigned int cmd,
9b9dbcca AC	112	unsigned long arg)
1da177e4 LT	113	{
	114	int options, retval = -EINVAL;
	115	static struct watchdog_info ident = {
	116	.options = WDIOF_KEEPALIVEPING \|
	117	WDIOF_MAGICCLOSE,
	118	.firmware_version = 0,
	119	.identity = "Hardware Watchdog for SGI IP22",
	120	};
	121
	122	switch (cmd) {
9b9dbcca AC	123	case WDIOC_GETSUPPORT:
	124	if (copy_to_user((struct watchdog_info *)arg,
	125	&ident, sizeof(ident)))
	126	return -EFAULT;
	127	return 0;
	128	case WDIOC_GETSTATUS:
	129	case WDIOC_GETBOOTSTATUS:
	130	return put_user(0, (int *)arg);
9b9dbcca AC	131	case WDIOC_SETOPTIONS:
	132	{
	133	if (get_user(options, (int *)arg))
	134	return -EFAULT;
	135	if (options & WDIOS_DISABLECARD) {
	136	indydog_stop();
	137	retval = 0;
	138	}
	139	if (options & WDIOS_ENABLECARD) {
	140	indydog_start();
	141	retval = 0;
1da177e4	142	}
9b9dbcca AC	143	return retval;
9b9dbcca AC	144	}
0c06090c WVS	145	case WDIOC_KEEPALIVE:
	146	indydog_ping();
	147	return 0;
	148	case WDIOC_GETTIMEOUT:
	149	return put_user(WATCHDOG_TIMEOUT, (int *)arg);
9b9dbcca AC	150	default:
9b9dbcca AC	151	return -ENOTTY;
1da177e4 LT	152	}
	153	}
	154
9b9dbcca AC	155	static int indydog_notify_sys(struct notifier_block *this,
9b9dbcca AC	156	unsigned long code, void *unused)
1da177e4 LT	157	{
	158	if (code == SYS_DOWN \|\| code == SYS_HALT)
	159	indydog_stop(); /* Turn the WDT off */
	160
	161	return NOTIFY_DONE;
	162	}
	163
62322d25	164	static const struct file_operations indydog_fops = {
1da177e4 LT	165	.owner = THIS_MODULE,
	166	.llseek = no_llseek,
	167	.write = indydog_write,
9b9dbcca	168	.unlocked_ioctl = indydog_ioctl,
1da177e4 LT	169	.open = indydog_open,
	170	.release = indydog_release,
	171	};
	172
	173	static struct miscdevice indydog_miscdev = {
	174	.minor = WATCHDOG_MINOR,
	175	.name = "watchdog",
	176	.fops = &indydog_fops,
	177	};
	178
	179	static struct notifier_block indydog_notifier = {
	180	.notifier_call = indydog_notify_sys,
	181	};
	182
	183	static char banner[] __initdata =
	184	KERN_INFO PFX "Hardware Watchdog Timer for SGI IP22: 0.3\n";
	185
	186	static int __init watchdog_init(void)
	187	{
	188	int ret;
	189
9b9dbcca AC	190	spin_lock_init(&indydog_lock);
9b9dbcca AC	191
1da177e4 LT	192	ret = register_reboot_notifier(&indydog_notifier);
1da177e4 LT	193	if (ret) {
9b9dbcca AC	194	printk(KERN_ERR PFX
9b9dbcca AC	195	"cannot register reboot notifier (err=%d)\n", ret);
1da177e4 LT	196	return ret;
	197	}
	198
	199	ret = misc_register(&indydog_miscdev);
	200	if (ret) {
9b9dbcca AC	201	printk(KERN_ERR PFX
	202	"cannot register miscdev on minor=%d (err=%d)\n",
	203	WATCHDOG_MINOR, ret);
1da177e4 LT	204	unregister_reboot_notifier(&indydog_notifier);
	205	return ret;
	206	}
	207
	208	printk(banner);
	209
	210	return 0;
	211	}
	212
	213	static void __exit watchdog_exit(void)
	214	{
	215	misc_deregister(&indydog_miscdev);
	216	unregister_reboot_notifier(&indydog_notifier);
	217	}
	218
	219	module_init(watchdog_init);
	220	module_exit(watchdog_exit);
	221
	222	MODULE_AUTHOR("Guido Guenther <agx@sigxcpu.org>");
	223	MODULE_DESCRIPTION("Hardware Watchdog Device for SGI IP22");
	224	MODULE_LICENSE("GPL");
	225	MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);