[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>
 */

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

static unsigned long indydog_alive;
static DEFINE_SPINLOCK(indydog_lock);

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

static bool nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, bool, 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);

	pr_info("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();

	pr_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 const struct watchdog_info ident = {
		.options		= WDIOF_KEEPALIVEPING,
		.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 int __init watchdog_init(void)
{
	int ret;

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

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

	pr_info("Hardware Watchdog Timer for SGI IP22: 0.3\n");

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