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

/*
 *  MachZ ZF-Logic Watchdog Timer driver for Linux
 *
 *
 *  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.
 *
 *  The author does NOT admit liability nor provide warranty for
 *  any of this software. This material is provided "AS-IS" in
 *  the hope that it may be useful for others.
 *
 *  Author: Fernando Fuganti <fuganti@conectiva.com.br>
 *
 *  Based on sbc60xxwdt.c by Jakob Oestergaard
 *
 *
 *  We have two timers (wd#1, wd#2) driven by a 32 KHz clock with the
 *  following periods:
 *      wd#1 - 2 seconds;
 *      wd#2 - 7.2 ms;
 *  After the expiration of wd#1, it can generate a NMI, SCI, SMI, or
 *  a system RESET and it starts wd#2 that unconditionally will RESET
 *  the system when the counter reaches zero.
 *
 *  14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com>
 *      Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/timer.h>
#include <linux/jiffies.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/fs.h>
#include <linux/ioport.h>
#include <linux/notifier.h>
#include <linux/reboot.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/uaccess.h>


/* ports */
#define ZF_IOBASE	0x218
#define INDEX		0x218
#define DATA_B		0x219
#define DATA_W		0x21A
#define DATA_D		0x21A

/* indexes */			/* size */
#define ZFL_VERSION	0x02	/* 16   */
#define CONTROL		0x10	/* 16   */
#define STATUS		0x12	/* 8    */
#define COUNTER_1	0x0C	/* 16   */
#define COUNTER_2	0x0E	/* 8    */
#define PULSE_LEN	0x0F	/* 8    */

/* controls */
#define ENABLE_WD1	0x0001
#define ENABLE_WD2	0x0002
#define RESET_WD1	0x0010
#define RESET_WD2	0x0020
#define GEN_SCI		0x0100
#define GEN_NMI		0x0200
#define GEN_SMI		0x0400
#define GEN_RESET	0x0800


/* utilities */

#define WD1	0
#define WD2	1

#define zf_writew(port, data)  { outb(port, INDEX); outw(data, DATA_W); }
#define zf_writeb(port, data)  { outb(port, INDEX); outb(data, DATA_B); }
#define zf_get_ZFL_version()   zf_readw(ZFL_VERSION)


static unsigned short zf_readw(unsigned char port)
{
	outb(port, INDEX);
	return inw(DATA_W);
}


MODULE_AUTHOR("Fernando Fuganti <fuganti@conectiva.com.br>");
MODULE_DESCRIPTION("MachZ ZF-Logic Watchdog driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);

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) ")");

#define PFX "machzwd"

static const struct watchdog_info zf_info = {
	.options		= WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
	.firmware_version	= 1,
	.identity		= "ZF-Logic watchdog",
};


/*
 * action refers to action taken when watchdog resets
 * 0 = GEN_RESET
 * 1 = GEN_SMI
 * 2 = GEN_NMI
 * 3 = GEN_SCI
 * defaults to GEN_RESET (0)
 */
static int action;
module_param(action, int, 0);
MODULE_PARM_DESC(action, "after watchdog resets, generate: "
				"0 = RESET(*)  1 = SMI  2 = NMI  3 = SCI");

static void zf_ping(unsigned long data);

static int zf_action = GEN_RESET;
static unsigned long zf_is_open;
static char zf_expect_close;
static DEFINE_SPINLOCK(zf_port_lock);
static DEFINE_TIMER(zf_timer, zf_ping, 0, 0);
static unsigned long next_heartbeat;


/* timeout for user land heart beat (10 seconds) */
#define ZF_USER_TIMEO (HZ*10)

/* timeout for hardware watchdog (~500ms) */
#define ZF_HW_TIMEO (HZ/2)

/* number of ticks on WD#1 (driven by a 32KHz clock, 2s) */
#define ZF_CTIMEOUT 0xffff

#ifndef ZF_DEBUG
#define dprintk(format, args...)
#else
#define dprintk(format, args...)					\
	pr_debug(":%s:%d: " format, __func__, __LINE__ , ## args)
#endif


static inline void zf_set_status(unsigned char new)
{
	zf_writeb(STATUS, new);
}


/* CONTROL register functions */

static inline unsigned short zf_get_control(void)
{
	return zf_readw(CONTROL);
}

static inline void zf_set_control(unsigned short new)
{
	zf_writew(CONTROL, new);
}


/* WD#? counter functions */
/*
 *	Just set counter value
 */

static inline void zf_set_timer(unsigned short new, unsigned char n)
{
	switch (n) {
	case WD1:
		zf_writew(COUNTER_1, new);
	case WD2:
		zf_writeb(COUNTER_2, new > 0xff ? 0xff : new);
	default:
		return;
	}
}

/*
 * stop hardware timer
 */
static void zf_timer_off(void)
{
	unsigned int ctrl_reg = 0;
	unsigned long flags;

	/* stop internal ping */
	del_timer_sync(&zf_timer);

	spin_lock_irqsave(&zf_port_lock, flags);
	/* stop watchdog timer */
	ctrl_reg = zf_get_control();
	ctrl_reg |= (ENABLE_WD1|ENABLE_WD2);	/* disable wd1 and wd2 */
	ctrl_reg &= ~(ENABLE_WD1|ENABLE_WD2);
	zf_set_control(ctrl_reg);
	spin_unlock_irqrestore(&zf_port_lock, flags);

	pr_info("Watchdog timer is now disabled\n");
}


/*
 * start hardware timer
 */
static void zf_timer_on(void)
{
	unsigned int ctrl_reg = 0;
	unsigned long flags;

	spin_lock_irqsave(&zf_port_lock, flags);

	zf_writeb(PULSE_LEN, 0xff);

	zf_set_timer(ZF_CTIMEOUT, WD1);

	/* user land ping */
	next_heartbeat = jiffies + ZF_USER_TIMEO;

	/* start the timer for internal ping */
	mod_timer(&zf_timer, jiffies + ZF_HW_TIMEO);

	/* start watchdog timer */
	ctrl_reg = zf_get_control();
	ctrl_reg |= (ENABLE_WD1|zf_action);
	zf_set_control(ctrl_reg);
	spin_unlock_irqrestore(&zf_port_lock, flags);

	pr_info("Watchdog timer is now enabled\n");
}


static void zf_ping(unsigned long data)
{
	unsigned int ctrl_reg = 0;
	unsigned long flags;

	zf_writeb(COUNTER_2, 0xff);

	if (time_before(jiffies, next_heartbeat)) {
		dprintk("time_before: %ld\n", next_heartbeat - jiffies);
		/*
		 * reset event is activated by transition from 0 to 1 on
		 * RESET_WD1 bit and we assume that it is already zero...
		 */

		spin_lock_irqsave(&zf_port_lock, flags);
		ctrl_reg = zf_get_control();
		ctrl_reg |= RESET_WD1;
		zf_set_control(ctrl_reg);

		/* ...and nothing changes until here */
		ctrl_reg &= ~(RESET_WD1);
		zf_set_control(ctrl_reg);
		spin_unlock_irqrestore(&zf_port_lock, flags);

		mod_timer(&zf_timer, jiffies + ZF_HW_TIMEO);
	} else
		pr_crit("I will reset your machine\n");
}

static ssize_t zf_write(struct file *file, const char __user *buf, size_t count,
								loff_t *ppos)
{
	/* See if we got the magic character */
	if (count) {
		/*
		 * no need to check for close confirmation
		 * no way to disable watchdog ;)
		 */
		if (!nowayout) {
			size_t ofs;
			/*
			 * note: just in case someone wrote the magic character
			 * five months ago...
			 */
			zf_expect_close = 0;

			/* now scan */
			for (ofs = 0; ofs != count; ofs++) {
				char c;
				if (get_user(c, buf + ofs))
					return -EFAULT;
				if (c == 'V') {
					zf_expect_close = 42;
					dprintk("zf_expect_close = 42\n");
				}
			}
		}

		/*
		 * Well, anyhow someone wrote to us,
		 * we should return that favour
		 */
		next_heartbeat = jiffies + ZF_USER_TIMEO;
		dprintk("user ping at %ld\n", jiffies);
	}
	return count;
}

static long zf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
	void __user *argp = (void __user *)arg;
	int __user *p = argp;
	switch (cmd) {
	case WDIOC_GETSUPPORT:
		if (copy_to_user(argp, &zf_info, sizeof(zf_info)))
			return -EFAULT;
		break;
	case WDIOC_GETSTATUS:
	case WDIOC_GETBOOTSTATUS:
		return put_user(0, p);
	case WDIOC_KEEPALIVE:
		zf_ping(0);
		break;
	default:
		return -ENOTTY;
	}
	return 0;
}

static int zf_open(struct inode *inode, struct file *file)
{
	if (test_and_set_bit(0, &zf_is_open))
		return -EBUSY;
	if (nowayout)
		__module_get(THIS_MODULE);
	zf_timer_on();
	return nonseekable_open(inode, file);
}

static int zf_close(struct inode *inode, struct file *file)
{
	if (zf_expect_close == 42)
		zf_timer_off();
	else {
		del_timer(&zf_timer);
		pr_err("device file closed unexpectedly. Will not stop the WDT!\n");
	}
	clear_bit(0, &zf_is_open);
	zf_expect_close = 0;
	return 0;
}

/*
 * Notifier for system down
 */

static int zf_notify_sys(struct notifier_block *this, unsigned long code,
								void *unused)
{
	if (code == SYS_DOWN || code == SYS_HALT)
		zf_timer_off();
	return NOTIFY_DONE;
}

static const struct file_operations zf_fops = {
	.owner		= THIS_MODULE,
	.llseek		= no_llseek,
	.write		= zf_write,
	.unlocked_ioctl = zf_ioctl,
	.open		= zf_open,
	.release	= zf_close,
};

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


/*
 * The device needs to learn about soft shutdowns in order to
 * turn the timebomb registers off.
 */
static struct notifier_block zf_notifier = {
	.notifier_call = zf_notify_sys,
};

static void __init zf_show_action(int act)
{
	static const char * const str[] = { "RESET", "SMI", "NMI", "SCI" };

	pr_info("Watchdog using action = %s\n", str[act]);
}

static int __init zf_init(void)
{
	int ret;

	pr_info("MachZ ZF-Logic Watchdog driver initializing\n");

	ret = zf_get_ZFL_version();
	if (!ret || ret == 0xffff) {
		pr_warn("no ZF-Logic found\n");
		return -ENODEV;
	}

	if (action <= 3 && action >= 0)
		zf_action = zf_action >> action;
	else
		action = 0;

	zf_show_action(action);

	if (!request_region(ZF_IOBASE, 3, "MachZ ZFL WDT")) {
		pr_err("cannot reserve I/O ports at %d\n", ZF_IOBASE);
		ret = -EBUSY;
		goto no_region;
	}

	ret = register_reboot_notifier(&zf_notifier);
	if (ret) {
		pr_err("can't register reboot notifier (err=%d)\n", ret);
		goto no_reboot;
	}

	ret = misc_register(&zf_miscdev);
	if (ret) {
		pr_err("can't misc_register on minor=%d\n", WATCHDOG_MINOR);
		goto no_misc;
	}

	zf_set_status(0);
	zf_set_control(0);

	return 0;

no_misc:
	unregister_reboot_notifier(&zf_notifier);
no_reboot:
	release_region(ZF_IOBASE, 3);
no_region:
	return ret;
}


static void __exit zf_exit(void)
{
	zf_timer_off();

	misc_deregister(&zf_miscdev);
	unregister_reboot_notifier(&zf_notifier);
	release_region(ZF_IOBASE, 3);
}

module_init(zf_init);
module_exit(zf_exit);
Commit	Line	Data
	1	/*
	2	* MachZ ZF-Logic Watchdog Timer driver for Linux
	3	*
	4	*
	5	* This program is free software; you can redistribute it and/or
	6	* modify it under the terms of the GNU General Public License
	7	* as published by the Free Software Foundation; either version
	8	* 2 of the License, or (at your option) any later version.
	9	*
	10	* The author does NOT admit liability nor provide warranty for
	11	* any of this software. This material is provided "AS-IS" in
	12	* the hope that it may be useful for others.
	13	*
	14	* Author: Fernando Fuganti <fuganti@conectiva.com.br>
	15	*
	16	* Based on sbc60xxwdt.c by Jakob Oestergaard
	17	*
	18	*
	19	* We have two timers (wd#1, wd#2) driven by a 32 KHz clock with the
	20	* following periods:
	21	* wd#1 - 2 seconds;
	22	* wd#2 - 7.2 ms;
	23	* After the expiration of wd#1, it can generate a NMI, SCI, SMI, or
	24	* a system RESET and it starts wd#2 that unconditionally will RESET
	25	* the system when the counter reaches zero.
	26	*
	27	* 14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com>
	28	* Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT
	29	*/
	30
	31	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
	32
	33	#include <linux/module.h>
	34	#include <linux/moduleparam.h>
	35	#include <linux/types.h>
	36	#include <linux/timer.h>
	37	#include <linux/jiffies.h>
	38	#include <linux/miscdevice.h>
	39	#include <linux/watchdog.h>
	40	#include <linux/fs.h>
	41	#include <linux/ioport.h>
	42	#include <linux/notifier.h>
	43	#include <linux/reboot.h>
	44	#include <linux/init.h>
	45	#include <linux/io.h>
	46	#include <linux/uaccess.h>
	47
	48
	49	/* ports */
	50	#define ZF_IOBASE 0x218
	51	#define INDEX 0x218
	52	#define DATA_B 0x219
	53	#define DATA_W 0x21A
	54	#define DATA_D 0x21A
	55
	56	/* indexes / / size */
	57	#define ZFL_VERSION 0x02 /* 16 */
	58	#define CONTROL 0x10 /* 16 */
	59	#define STATUS 0x12 /* 8 */
	60	#define COUNTER_1 0x0C /* 16 */
	61	#define COUNTER_2 0x0E /* 8 */
	62	#define PULSE_LEN 0x0F /* 8 */
	63
	64	/* controls */
	65	#define ENABLE_WD1 0x0001
	66	#define ENABLE_WD2 0x0002
	67	#define RESET_WD1 0x0010
	68	#define RESET_WD2 0x0020
	69	#define GEN_SCI 0x0100
	70	#define GEN_NMI 0x0200
	71	#define GEN_SMI 0x0400
	72	#define GEN_RESET 0x0800
	73
	74
	75	/* utilities */
	76
	77	#define WD1 0
	78	#define WD2 1
	79
	80	#define zf_writew(port, data) { outb(port, INDEX); outw(data, DATA_W); }
	81	#define zf_writeb(port, data) { outb(port, INDEX); outb(data, DATA_B); }
	82	#define zf_get_ZFL_version() zf_readw(ZFL_VERSION)
	83
	84
	85	static unsigned short zf_readw(unsigned char port)
	86	{
	87	outb(port, INDEX);
	88	return inw(DATA_W);
	89	}
	90
	91
	92	MODULE_AUTHOR("Fernando Fuganti <fuganti@conectiva.com.br>");
	93	MODULE_DESCRIPTION("MachZ ZF-Logic Watchdog driver");
	94	MODULE_LICENSE("GPL");
	95	MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
	96
	97	static bool nowayout = WATCHDOG_NOWAYOUT;
	98	module_param(nowayout, bool, 0);
	99	MODULE_PARM_DESC(nowayout,
	100	"Watchdog cannot be stopped once started (default="
	101	__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
	102
	103	#define PFX "machzwd"
	104
	105	static const struct watchdog_info zf_info = {
	106	.options = WDIOF_KEEPALIVEPING \| WDIOF_MAGICCLOSE,
	107	.firmware_version = 1,
	108	.identity = "ZF-Logic watchdog",
	109	};
	110
	111
	112	/*
	113	* action refers to action taken when watchdog resets
	114	* 0 = GEN_RESET
	115	* 1 = GEN_SMI
	116	* 2 = GEN_NMI
	117	* 3 = GEN_SCI
	118	* defaults to GEN_RESET (0)
	119	*/
	120	static int action;
	121	module_param(action, int, 0);
	122	MODULE_PARM_DESC(action, "after watchdog resets, generate: "
	123	"0 = RESET(*) 1 = SMI 2 = NMI 3 = SCI");
	124
	125	static void zf_ping(unsigned long data);
	126
	127	static int zf_action = GEN_RESET;
	128	static unsigned long zf_is_open;
	129	static char zf_expect_close;
	130	static DEFINE_SPINLOCK(zf_port_lock);
	131	static DEFINE_TIMER(zf_timer, zf_ping, 0, 0);
	132	static unsigned long next_heartbeat;
	133
	134
	135	/* timeout for user land heart beat (10 seconds) */
	136	#define ZF_USER_TIMEO (HZ*10)
	137
	138	/* timeout for hardware watchdog (~500ms) */
	139	#define ZF_HW_TIMEO (HZ/2)
	140
	141	/* number of ticks on WD#1 (driven by a 32KHz clock, 2s) */
	142	#define ZF_CTIMEOUT 0xffff
	143
	144	#ifndef ZF_DEBUG
	145	#define dprintk(format, args...)
	146	#else
	147	#define dprintk(format, args...) \
	148	pr_debug(":%s:%d: " format, __func__, __LINE__ , ## args)
	149	#endif
	150
	151
	152	static inline void zf_set_status(unsigned char new)
	153	{
	154	zf_writeb(STATUS, new);
	155	}
	156
	157
	158	/* CONTROL register functions */
	159
	160	static inline unsigned short zf_get_control(void)
	161	{
	162	return zf_readw(CONTROL);
	163	}
	164
	165	static inline void zf_set_control(unsigned short new)
	166	{
	167	zf_writew(CONTROL, new);
	168	}
	169
	170
	171	/* WD#? counter functions */
	172	/*
	173	* Just set counter value
	174	*/
	175
	176	static inline void zf_set_timer(unsigned short new, unsigned char n)
	177	{
	178	switch (n) {
	179	case WD1:
	180	zf_writew(COUNTER_1, new);
	181	case WD2:
	182	zf_writeb(COUNTER_2, new > 0xff ? 0xff : new);
	183	default:
	184	return;
	185	}
	186	}
	187
	188	/*
	189	* stop hardware timer
	190	*/
	191	static void zf_timer_off(void)
	192	{
	193	unsigned int ctrl_reg = 0;
	194	unsigned long flags;
	195
	196	/* stop internal ping */
	197	del_timer_sync(&zf_timer);
	198
	199	spin_lock_irqsave(&zf_port_lock, flags);
	200	/* stop watchdog timer */
	201	ctrl_reg = zf_get_control();
	202	ctrl_reg \|= (ENABLE_WD1\|ENABLE_WD2); /* disable wd1 and wd2 */
	203	ctrl_reg &= ~(ENABLE_WD1\|ENABLE_WD2);
	204	zf_set_control(ctrl_reg);
	205	spin_unlock_irqrestore(&zf_port_lock, flags);
	206
	207	pr_info("Watchdog timer is now disabled\n");
	208	}
	209
	210
	211	/*
	212	* start hardware timer
	213	*/
	214	static void zf_timer_on(void)
	215	{
	216	unsigned int ctrl_reg = 0;
	217	unsigned long flags;
	218
	219	spin_lock_irqsave(&zf_port_lock, flags);
	220
	221	zf_writeb(PULSE_LEN, 0xff);
	222
	223	zf_set_timer(ZF_CTIMEOUT, WD1);
	224
	225	/* user land ping */
	226	next_heartbeat = jiffies + ZF_USER_TIMEO;
	227
	228	/* start the timer for internal ping */
	229	mod_timer(&zf_timer, jiffies + ZF_HW_TIMEO);
	230
	231	/* start watchdog timer */
	232	ctrl_reg = zf_get_control();
	233	ctrl_reg \|= (ENABLE_WD1\|zf_action);
	234	zf_set_control(ctrl_reg);
	235	spin_unlock_irqrestore(&zf_port_lock, flags);
	236
	237	pr_info("Watchdog timer is now enabled\n");
	238	}
	239
	240
	241	static void zf_ping(unsigned long data)
	242	{
	243	unsigned int ctrl_reg = 0;
	244	unsigned long flags;
	245
	246	zf_writeb(COUNTER_2, 0xff);
	247
	248	if (time_before(jiffies, next_heartbeat)) {
	249	dprintk("time_before: %ld\n", next_heartbeat - jiffies);
	250	/*
	251	* reset event is activated by transition from 0 to 1 on
	252	* RESET_WD1 bit and we assume that it is already zero...
	253	*/
	254
	255	spin_lock_irqsave(&zf_port_lock, flags);
	256	ctrl_reg = zf_get_control();
	257	ctrl_reg \|= RESET_WD1;
	258	zf_set_control(ctrl_reg);
	259
	260	/* ...and nothing changes until here */
	261	ctrl_reg &= ~(RESET_WD1);
	262	zf_set_control(ctrl_reg);
	263	spin_unlock_irqrestore(&zf_port_lock, flags);
	264
	265	mod_timer(&zf_timer, jiffies + ZF_HW_TIMEO);
	266	} else
	267	pr_crit("I will reset your machine\n");
	268	}
	269
	270	static ssize_t zf_write(struct file file, const char __user buf, size_t count,
	271	loff_t *ppos)
	272	{
	273	/* See if we got the magic character */
	274	if (count) {
	275	/*
	276	* no need to check for close confirmation
	277	* no way to disable watchdog ;)
	278	*/
	279	if (!nowayout) {
	280	size_t ofs;
	281	/*
	282	* note: just in case someone wrote the magic character
	283	* five months ago...
	284	*/
	285	zf_expect_close = 0;
	286
	287	/* now scan */
	288	for (ofs = 0; ofs != count; ofs++) {
	289	char c;
	290	if (get_user(c, buf + ofs))
	291	return -EFAULT;
	292	if (c == 'V') {
	293	zf_expect_close = 42;
	294	dprintk("zf_expect_close = 42\n");
	295	}
	296	}
	297	}
	298
	299	/*
	300	* Well, anyhow someone wrote to us,
	301	* we should return that favour
	302	*/
	303	next_heartbeat = jiffies + ZF_USER_TIMEO;
	304	dprintk("user ping at %ld\n", jiffies);
	305	}
	306	return count;
	307	}
	308
	309	static long zf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
	310	{
	311	void __user argp = (void __user )arg;
	312	int __user *p = argp;
	313	switch (cmd) {
	314	case WDIOC_GETSUPPORT:
	315	if (copy_to_user(argp, &zf_info, sizeof(zf_info)))
	316	return -EFAULT;
	317	break;
	318	case WDIOC_GETSTATUS:
	319	case WDIOC_GETBOOTSTATUS:
	320	return put_user(0, p);
	321	case WDIOC_KEEPALIVE:
	322	zf_ping(0);
	323	break;
	324	default:
	325	return -ENOTTY;
	326	}
	327	return 0;
	328	}
	329
	330	static int zf_open(struct inode inode, struct file file)
	331	{
	332	if (test_and_set_bit(0, &zf_is_open))
	333	return -EBUSY;
	334	if (nowayout)
	335	__module_get(THIS_MODULE);
	336	zf_timer_on();
	337	return nonseekable_open(inode, file);
	338	}
	339
	340	static int zf_close(struct inode inode, struct file file)
	341	{
	342	if (zf_expect_close == 42)
	343	zf_timer_off();
	344	else {
	345	del_timer(&zf_timer);
	346	pr_err("device file closed unexpectedly. Will not stop the WDT!\n");
	347	}
	348	clear_bit(0, &zf_is_open);
	349	zf_expect_close = 0;
	350	return 0;
	351	}
	352
	353	/*
	354	* Notifier for system down
	355	*/
	356
	357	static int zf_notify_sys(struct notifier_block *this, unsigned long code,
	358	void *unused)
	359	{
	360	if (code == SYS_DOWN \|\| code == SYS_HALT)
	361	zf_timer_off();
	362	return NOTIFY_DONE;
	363	}
	364
	365	static const struct file_operations zf_fops = {
	366	.owner = THIS_MODULE,
	367	.llseek = no_llseek,
	368	.write = zf_write,
	369	.unlocked_ioctl = zf_ioctl,
	370	.open = zf_open,
	371	.release = zf_close,
	372	};
	373
	374	static struct miscdevice zf_miscdev = {
	375	.minor = WATCHDOG_MINOR,
	376	.name = "watchdog",
	377	.fops = &zf_fops,
	378	};
	379
	380
	381	/*
	382	* The device needs to learn about soft shutdowns in order to
	383	* turn the timebomb registers off.
	384	*/
	385	static struct notifier_block zf_notifier = {
	386	.notifier_call = zf_notify_sys,
	387	};
	388
	389	static void __init zf_show_action(int act)
	390	{
	391	static const char * const str[] = { "RESET", "SMI", "NMI", "SCI" };
	392
	393	pr_info("Watchdog using action = %s\n", str[act]);
	394	}
	395
	396	static int __init zf_init(void)
	397	{
	398	int ret;
	399
	400	pr_info("MachZ ZF-Logic Watchdog driver initializing\n");
	401
	402	ret = zf_get_ZFL_version();
	403	if (!ret \|\| ret == 0xffff) {
	404	pr_warn("no ZF-Logic found\n");
	405	return -ENODEV;
	406	}
	407
	408	if (action <= 3 && action >= 0)
	409	zf_action = zf_action >> action;
	410	else
	411	action = 0;
	412
	413	zf_show_action(action);
	414
	415	if (!request_region(ZF_IOBASE, 3, "MachZ ZFL WDT")) {
	416	pr_err("cannot reserve I/O ports at %d\n", ZF_IOBASE);
	417	ret = -EBUSY;
	418	goto no_region;
	419	}
	420
	421	ret = register_reboot_notifier(&zf_notifier);
	422	if (ret) {
	423	pr_err("can't register reboot notifier (err=%d)\n", ret);
	424	goto no_reboot;
	425	}
	426
	427	ret = misc_register(&zf_miscdev);
	428	if (ret) {
	429	pr_err("can't misc_register on minor=%d\n", WATCHDOG_MINOR);
	430	goto no_misc;
	431	}
	432
	433	zf_set_status(0);
	434	zf_set_control(0);
	435
	436	return 0;
	437
	438	no_misc:
	439	unregister_reboot_notifier(&zf_notifier);
	440	no_reboot:
	441	release_region(ZF_IOBASE, 3);
	442	no_region:
	443	return ret;
	444	}
	445
	446
	447	static void __exit zf_exit(void)
	448	{
	449	zf_timer_off();
	450
	451	misc_deregister(&zf_miscdev);
	452	unregister_reboot_notifier(&zf_notifier);
	453	release_region(ZF_IOBASE, 3);
	454	}
	455
	456	module_init(zf_init);
	457	module_exit(zf_exit);