[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");

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
1da177e4 LT	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
af901ca1	24	* a system RESET and it starts wd#2 that unconditionally will RESET
1da177e4 LT	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
27c766aa JP	31	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
27c766aa JP	32
1da177e4 LT	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>
325ea4d3 AC	45	#include <linux/io.h>
325ea4d3 AC	46	#include <linux/uaccess.h>
1da177e4	47
1da177e4 LT	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 */
5f3b2756	58	#define CONTROL 0x10 /* 16 */
1da177e4 LT	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");
1da177e4	95
86a1e189 WVS	96	static bool nowayout = WATCHDOG_NOWAYOUT;
86a1e189 WVS	97	module_param(nowayout, bool, 0);
325ea4d3 AC	98	MODULE_PARM_DESC(nowayout,
	99	"Watchdog cannot be stopped once started (default="
	100	__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
1da177e4 LT	101
	102	#define PFX "machzwd"
	103
42747d71	104	static const struct watchdog_info zf_info = {
1da177e4 LT	105	.options = WDIOF_KEEPALIVEPING \| WDIOF_MAGICCLOSE,
	106	.firmware_version = 1,
	107	.identity = "ZF-Logic watchdog",
	108	};
	109
	110
	111	/*
	112	* action refers to action taken when watchdog resets
	113	* 0 = GEN_RESET
	114	* 1 = GEN_SMI
	115	* 2 = GEN_NMI
	116	* 3 = GEN_SCI
	117	* defaults to GEN_RESET (0)
	118	*/
325ea4d3	119	static int action;
1da177e4	120	module_param(action, int, 0);
a77dba7e WVS	121	MODULE_PARM_DESC(action, "after watchdog resets, generate: "
a77dba7e WVS	122	"0 = RESET(*) 1 = SMI 2 = NMI 3 = SCI");
1da177e4	123
82eb7c50 JS	124	static void zf_ping(unsigned long data);
82eb7c50 JS	125
1da177e4 LT	126	static int zf_action = GEN_RESET;
	127	static unsigned long zf_is_open;
	128	static char zf_expect_close;
c7dfd0cc	129	static DEFINE_SPINLOCK(zf_port_lock);
82eb7c50	130	static DEFINE_TIMER(zf_timer, zf_ping, 0, 0);
325ea4d3	131	static unsigned long next_heartbeat;
1da177e4 LT	132
	133
	134	/* timeout for user land heart beat (10 seconds) */
	135	#define ZF_USER_TIMEO (HZ*10)
	136
	137	/* timeout for hardware watchdog (~500ms) */
	138	#define ZF_HW_TIMEO (HZ/2)
	139
	140	/* number of ticks on WD#1 (driven by a 32KHz clock, 2s) */
	141	#define ZF_CTIMEOUT 0xffff
	142
	143	#ifndef ZF_DEBUG
27c766aa	144	#define dprintk(format, args...)
1da177e4	145	#else
27c766aa JP	146	#define dprintk(format, args...) \
27c766aa JP	147	pr_debug(":%s:%d: " format, __func__, __LINE__ , ## args)
1da177e4 LT	148	#endif
	149
	150
	151	static inline void zf_set_status(unsigned char new)
	152	{
	153	zf_writeb(STATUS, new);
	154	}
	155
	156
	157	/* CONTROL register functions */
	158
	159	static inline unsigned short zf_get_control(void)
	160	{
	161	return zf_readw(CONTROL);
	162	}
	163
	164	static inline void zf_set_control(unsigned short new)
	165	{
	166	zf_writew(CONTROL, new);
	167	}
	168
	169
	170	/* WD#? counter functions */
	171	/*
	172	* Just set counter value
	173	*/
	174
	175	static inline void zf_set_timer(unsigned short new, unsigned char n)
	176	{
325ea4d3 AC	177	switch (n) {
	178	case WD1:
	179	zf_writew(COUNTER_1, new);
	180	case WD2:
	181	zf_writeb(COUNTER_2, new > 0xff ? 0xff : new);
	182	default:
	183	return;
1da177e4 LT	184	}
	185	}
	186
	187	/*
	188	* stop hardware timer
	189	*/
	190	static void zf_timer_off(void)
	191	{
	192	unsigned int ctrl_reg = 0;
	193	unsigned long flags;
	194
	195	/* stop internal ping */
	196	del_timer_sync(&zf_timer);
	197
	198	spin_lock_irqsave(&zf_port_lock, flags);
	199	/* stop watchdog timer */
	200	ctrl_reg = zf_get_control();
	201	ctrl_reg \|= (ENABLE_WD1\|ENABLE_WD2); /* disable wd1 and wd2 */
	202	ctrl_reg &= ~(ENABLE_WD1\|ENABLE_WD2);
	203	zf_set_control(ctrl_reg);
	204	spin_unlock_irqrestore(&zf_port_lock, flags);
	205
27c766aa	206	pr_info("Watchdog timer is now disabled\n");
1da177e4 LT	207	}
	208
	209
	210	/*
	211	* start hardware timer
	212	*/
	213	static void zf_timer_on(void)
	214	{
	215	unsigned int ctrl_reg = 0;
	216	unsigned long flags;
	217
	218	spin_lock_irqsave(&zf_port_lock, flags);
	219
	220	zf_writeb(PULSE_LEN, 0xff);
	221
	222	zf_set_timer(ZF_CTIMEOUT, WD1);
	223
	224	/* user land ping */
	225	next_heartbeat = jiffies + ZF_USER_TIMEO;
	226
	227	/* start the timer for internal ping */
82eb7c50	228	mod_timer(&zf_timer, jiffies + ZF_HW_TIMEO);
1da177e4 LT	229
	230	/* start watchdog timer */
	231	ctrl_reg = zf_get_control();
	232	ctrl_reg \|= (ENABLE_WD1\|zf_action);
	233	zf_set_control(ctrl_reg);
	234	spin_unlock_irqrestore(&zf_port_lock, flags);
	235
27c766aa	236	pr_info("Watchdog timer is now enabled\n");
1da177e4 LT	237	}
	238
	239
	240	static void zf_ping(unsigned long data)
	241	{
	242	unsigned int ctrl_reg = 0;
	243	unsigned long flags;
	244
	245	zf_writeb(COUNTER_2, 0xff);
	246
325ea4d3	247	if (time_before(jiffies, next_heartbeat)) {
1da177e4	248	dprintk("time_before: %ld\n", next_heartbeat - jiffies);
1da177e4 LT	249	/*
	250	* reset event is activated by transition from 0 to 1 on
	251	* RESET_WD1 bit and we assume that it is already zero...
	252	*/
	253
	254	spin_lock_irqsave(&zf_port_lock, flags);
	255	ctrl_reg = zf_get_control();
	256	ctrl_reg \|= RESET_WD1;
	257	zf_set_control(ctrl_reg);
	258
	259	/* ...and nothing changes until here */
	260	ctrl_reg &= ~(RESET_WD1);
	261	zf_set_control(ctrl_reg);
	262	spin_unlock_irqrestore(&zf_port_lock, flags);
	263
82eb7c50	264	mod_timer(&zf_timer, jiffies + ZF_HW_TIMEO);
325ea4d3	265	} else
27c766aa	266	pr_crit("I will reset your machine\n");
1da177e4 LT	267	}
	268
	269	static ssize_t zf_write(struct file file, const char __user buf, size_t count,
	270	loff_t *ppos)
	271	{
	272	/* See if we got the magic character */
325ea4d3	273	if (count) {
1da177e4 LT	274	/*
	275	* no need to check for close confirmation
	276	* no way to disable watchdog ;)
	277	*/
	278	if (!nowayout) {
	279	size_t ofs;
1da177e4 LT	280	/*
	281	* note: just in case someone wrote the magic character
	282	* five months ago...
	283	*/
	284	zf_expect_close = 0;
	285
	286	/* now scan */
325ea4d3	287	for (ofs = 0; ofs != count; ofs++) {
1da177e4 LT	288	char c;
	289	if (get_user(c, buf + ofs))
	290	return -EFAULT;
325ea4d3	291	if (c == 'V') {
1da177e4 LT	292	zf_expect_close = 42;
	293	dprintk("zf_expect_close = 42\n");
	294	}
	295	}
	296	}
	297
	298	/*
	299	* Well, anyhow someone wrote to us,
	300	* we should return that favour
	301	*/
	302	next_heartbeat = jiffies + ZF_USER_TIMEO;
	303	dprintk("user ping at %ld\n", jiffies);
1da177e4	304	}
1da177e4 LT	305	return count;
	306	}
	307
325ea4d3	308	static long zf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1da177e4 LT	309	{
	310	void __user argp = (void __user )arg;
	311	int __user *p = argp;
bad77057 AM	312	switch (cmd) {
	313	case WDIOC_GETSUPPORT:
	314	if (copy_to_user(argp, &zf_info, sizeof(zf_info)))
	315	return -EFAULT;
	316	break;
bad77057	317	case WDIOC_GETSTATUS:
5c4eb61b	318	case WDIOC_GETBOOTSTATUS:
bad77057	319	return put_user(0, p);
bad77057 AM	320	case WDIOC_KEEPALIVE:
	321	zf_ping(0);
	322	break;
bad77057 AM	323	default:
bad77057 AM	324	return -ENOTTY;
1da177e4	325	}
1da177e4 LT	326	return 0;
	327	}
	328
	329	static int zf_open(struct inode inode, struct file file)
	330	{
325ea4d3	331	if (test_and_set_bit(0, &zf_is_open))
1da177e4	332	return -EBUSY;
1da177e4 LT	333	if (nowayout)
1da177e4 LT	334	__module_get(THIS_MODULE);
1da177e4	335	zf_timer_on();
1da177e4 LT	336	return nonseekable_open(inode, file);
	337	}
	338
	339	static int zf_close(struct inode inode, struct file file)
	340	{
325ea4d3	341	if (zf_expect_close == 42)
1da177e4	342	zf_timer_off();
325ea4d3	343	else {
1da177e4	344	del_timer(&zf_timer);
27c766aa	345	pr_err("device file closed unexpectedly. Will not stop the WDT!\n");
1da177e4	346	}
1da177e4	347	clear_bit(0, &zf_is_open);
1da177e4	348	zf_expect_close = 0;
1da177e4 LT	349	return 0;
	350	}
	351
	352	/*
	353	* Notifier for system down
	354	*/
	355
	356	static int zf_notify_sys(struct notifier_block *this, unsigned long code,
	357	void *unused)
	358	{
325ea4d3	359	if (code == SYS_DOWN \|\| code == SYS_HALT)
1da177e4	360	zf_timer_off();
1da177e4 LT	361	return NOTIFY_DONE;
	362	}
	363
62322d25	364	static const struct file_operations zf_fops = {
325ea4d3 AC	365	.owner = THIS_MODULE,
	366	.llseek = no_llseek,
	367	.write = zf_write,
	368	.unlocked_ioctl = zf_ioctl,
	369	.open = zf_open,
	370	.release = zf_close,
1da177e4 LT	371	};
	372
	373	static struct miscdevice zf_miscdev = {
	374	.minor = WATCHDOG_MINOR,
	375	.name = "watchdog",
	376	.fops = &zf_fops,
	377	};
325ea4d3	378
1da177e4 LT	379
	380	/*
	381	* The device needs to learn about soft shutdowns in order to
	382	* turn the timebomb registers off.
	383	*/
	384	static struct notifier_block zf_notifier = {
	385	.notifier_call = zf_notify_sys,
	386	};
	387
	388	static void __init zf_show_action(int act)
	389	{
a2b89cd8	390	static const char * const str[] = { "RESET", "SMI", "NMI", "SCI" };
1da177e4	391
27c766aa	392	pr_info("Watchdog using action = %s\n", str[act]);
1da177e4 LT	393	}
	394
	395	static int __init zf_init(void)
	396	{
	397	int ret;
	398
27c766aa	399	pr_info("MachZ ZF-Logic Watchdog driver initializing\n");
1da177e4 LT	400
1da177e4 LT	401	ret = zf_get_ZFL_version();
325ea4d3	402	if (!ret \|\| ret == 0xffff) {
27c766aa	403	pr_warn("no ZF-Logic found\n");
1da177e4 LT	404	return -ENODEV;
	405	}
	406
325ea4d3 AC	407	if (action <= 3 && action >= 0)
	408	zf_action = zf_action >> action;
	409	else
1da177e4 LT	410	action = 0;
	411
	412	zf_show_action(action);
	413
325ea4d3	414	if (!request_region(ZF_IOBASE, 3, "MachZ ZFL WDT")) {
27c766aa	415	pr_err("cannot reserve I/O ports at %d\n", ZF_IOBASE);
1da177e4 LT	416	ret = -EBUSY;
	417	goto no_region;
	418	}
	419
	420	ret = register_reboot_notifier(&zf_notifier);
325ea4d3	421	if (ret) {
27c766aa	422	pr_err("can't register reboot notifier (err=%d)\n", ret);
1da177e4 LT	423	goto no_reboot;
	424	}
	425
fb8f7ba0	426	ret = misc_register(&zf_miscdev);
325ea4d3	427	if (ret) {
27c766aa	428	pr_err("can't misc_register on minor=%d\n", WATCHDOG_MINOR);
fb8f7ba0 AD	429	goto no_misc;
	430	}
	431
1da177e4 LT	432	zf_set_status(0);
	433	zf_set_control(0);
	434
1da177e4 LT	435	return 0;
1da177e4 LT	436
fb8f7ba0 AD	437	no_misc:
fb8f7ba0 AD	438	unregister_reboot_notifier(&zf_notifier);
1da177e4 LT	439	no_reboot:
	440	release_region(ZF_IOBASE, 3);
	441	no_region:
1da177e4 LT	442	return ret;
	443	}
	444
	445
	446	static void __exit zf_exit(void)
	447	{
	448	zf_timer_off();
	449
	450	misc_deregister(&zf_miscdev);
	451	unregister_reboot_notifier(&zf_notifier);
	452	release_region(ZF_IOBASE, 3);
	453	}
	454
	455	module_init(zf_init);
	456	module_exit(zf_exit);