[mirror_ubuntu-jammy-kernel.git] / drivers / watchdog / machzwd.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  MachZ ZF-Logic Watchdog Timer driver for Linux
 *
 *  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(struct timer_list *unused);

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);
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);
		fallthrough;
	case WD2:
		zf_writeb(COUNTER_2, new > 0xff ? 0xff : new);
		fallthrough;
	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(struct timer_list *unused)
{
	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(NULL);
		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 stream_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,
	.compat_ioctl	= compat_ptr_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
2874c5fd	1	// SPDX-License-Identifier: GPL-2.0-or-later
1da177e4 LT	2	/*
	3	* MachZ ZF-Logic Watchdog Timer driver for Linux
	4	*
1da177e4 LT	5	* The author does NOT admit liability nor provide warranty for
	6	* any of this software. This material is provided "AS-IS" in
	7	* the hope that it may be useful for others.
	8	*
	9	* Author: Fernando Fuganti <fuganti@conectiva.com.br>
	10	*
	11	* Based on sbc60xxwdt.c by Jakob Oestergaard
	12	*
1da177e4 LT	13	* We have two timers (wd#1, wd#2) driven by a 32 KHz clock with the
	14	* following periods:
	15	* wd#1 - 2 seconds;
	16	* wd#2 - 7.2 ms;
	17	* After the expiration of wd#1, it can generate a NMI, SCI, SMI, or
af901ca1	18	* a system RESET and it starts wd#2 that unconditionally will RESET
1da177e4 LT	19	* the system when the counter reaches zero.
	20	*
	21	* 14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com>
	22	* Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT
	23	*/
	24
27c766aa JP	25	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
27c766aa JP	26
1da177e4 LT	27	#include <linux/module.h>
	28	#include <linux/moduleparam.h>
	29	#include <linux/types.h>
	30	#include <linux/timer.h>
	31	#include <linux/jiffies.h>
	32	#include <linux/miscdevice.h>
	33	#include <linux/watchdog.h>
	34	#include <linux/fs.h>
	35	#include <linux/ioport.h>
	36	#include <linux/notifier.h>
	37	#include <linux/reboot.h>
	38	#include <linux/init.h>
325ea4d3 AC	39	#include <linux/io.h>
325ea4d3 AC	40	#include <linux/uaccess.h>
1da177e4	41
1da177e4 LT	42
	43	/* ports */
	44	#define ZF_IOBASE 0x218
	45	#define INDEX 0x218
	46	#define DATA_B 0x219
	47	#define DATA_W 0x21A
	48	#define DATA_D 0x21A
	49
	50	/* indexes / / size */
	51	#define ZFL_VERSION 0x02 /* 16 */
5f3b2756	52	#define CONTROL 0x10 /* 16 */
1da177e4 LT	53	#define STATUS 0x12 /* 8 */
	54	#define COUNTER_1 0x0C /* 16 */
	55	#define COUNTER_2 0x0E /* 8 */
	56	#define PULSE_LEN 0x0F /* 8 */
	57
	58	/* controls */
	59	#define ENABLE_WD1 0x0001
	60	#define ENABLE_WD2 0x0002
	61	#define RESET_WD1 0x0010
	62	#define RESET_WD2 0x0020
	63	#define GEN_SCI 0x0100
	64	#define GEN_NMI 0x0200
	65	#define GEN_SMI 0x0400
	66	#define GEN_RESET 0x0800
	67
	68
	69	/* utilities */
	70
	71	#define WD1 0
	72	#define WD2 1
	73
	74	#define zf_writew(port, data) { outb(port, INDEX); outw(data, DATA_W); }
	75	#define zf_writeb(port, data) { outb(port, INDEX); outb(data, DATA_B); }
	76	#define zf_get_ZFL_version() zf_readw(ZFL_VERSION)
	77
	78
	79	static unsigned short zf_readw(unsigned char port)
	80	{
	81	outb(port, INDEX);
	82	return inw(DATA_W);
	83	}
	84
	85
	86	MODULE_AUTHOR("Fernando Fuganti <fuganti@conectiva.com.br>");
	87	MODULE_DESCRIPTION("MachZ ZF-Logic Watchdog driver");
	88	MODULE_LICENSE("GPL");
1da177e4	89
86a1e189 WVS	90	static bool nowayout = WATCHDOG_NOWAYOUT;
86a1e189 WVS	91	module_param(nowayout, bool, 0);
325ea4d3 AC	92	MODULE_PARM_DESC(nowayout,
	93	"Watchdog cannot be stopped once started (default="
	94	__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
1da177e4 LT	95
	96	#define PFX "machzwd"
	97
42747d71	98	static const struct watchdog_info zf_info = {
1da177e4 LT	99	.options = WDIOF_KEEPALIVEPING \| WDIOF_MAGICCLOSE,
	100	.firmware_version = 1,
	101	.identity = "ZF-Logic watchdog",
	102	};
	103
	104
	105	/*
	106	* action refers to action taken when watchdog resets
	107	* 0 = GEN_RESET
	108	* 1 = GEN_SMI
	109	* 2 = GEN_NMI
	110	* 3 = GEN_SCI
	111	* defaults to GEN_RESET (0)
	112	*/
325ea4d3	113	static int action;
1da177e4	114	module_param(action, int, 0);
a77dba7e WVS	115	MODULE_PARM_DESC(action, "after watchdog resets, generate: "
a77dba7e WVS	116	"0 = RESET(*) 1 = SMI 2 = NMI 3 = SCI");
1da177e4	117
24ed960a	118	static void zf_ping(struct timer_list *unused);
82eb7c50	119
1da177e4 LT	120	static int zf_action = GEN_RESET;
	121	static unsigned long zf_is_open;
	122	static char zf_expect_close;
c7dfd0cc	123	static DEFINE_SPINLOCK(zf_port_lock);
1d27e3e2	124	static DEFINE_TIMER(zf_timer, zf_ping);
325ea4d3	125	static unsigned long next_heartbeat;
1da177e4 LT	126
	127
	128	/* timeout for user land heart beat (10 seconds) */
	129	#define ZF_USER_TIMEO (HZ*10)
	130
	131	/* timeout for hardware watchdog (~500ms) */
	132	#define ZF_HW_TIMEO (HZ/2)
	133
	134	/* number of ticks on WD#1 (driven by a 32KHz clock, 2s) */
	135	#define ZF_CTIMEOUT 0xffff
	136
	137	#ifndef ZF_DEBUG
27c766aa	138	#define dprintk(format, args...)
1da177e4	139	#else
27c766aa JP	140	#define dprintk(format, args...) \
27c766aa JP	141	pr_debug(":%s:%d: " format, __func__, __LINE__ , ## args)
1da177e4 LT	142	#endif
	143
	144
	145	static inline void zf_set_status(unsigned char new)
	146	{
	147	zf_writeb(STATUS, new);
	148	}
	149
	150
	151	/* CONTROL register functions */
	152
	153	static inline unsigned short zf_get_control(void)
	154	{
	155	return zf_readw(CONTROL);
	156	}
	157
	158	static inline void zf_set_control(unsigned short new)
	159	{
	160	zf_writew(CONTROL, new);
	161	}
	162
	163
	164	/* WD#? counter functions */
	165	/*
	166	* Just set counter value
	167	*/
	168
	169	static inline void zf_set_timer(unsigned short new, unsigned char n)
	170	{
325ea4d3 AC	171	switch (n) {
	172	case WD1:
	173	zf_writew(COUNTER_1, new);
bd490f82	174	fallthrough;
325ea4d3 AC	175	case WD2:
325ea4d3 AC	176	zf_writeb(COUNTER_2, new > 0xff ? 0xff : new);
18a0e8d0	177	fallthrough;
325ea4d3 AC	178	default:
325ea4d3 AC	179	return;
1da177e4 LT	180	}
	181	}
	182
	183	/*
	184	* stop hardware timer
	185	*/
	186	static void zf_timer_off(void)
	187	{
	188	unsigned int ctrl_reg = 0;
	189	unsigned long flags;
	190
	191	/* stop internal ping */
	192	del_timer_sync(&zf_timer);
	193
	194	spin_lock_irqsave(&zf_port_lock, flags);
	195	/* stop watchdog timer */
	196	ctrl_reg = zf_get_control();
	197	ctrl_reg \|= (ENABLE_WD1\|ENABLE_WD2); /* disable wd1 and wd2 */
	198	ctrl_reg &= ~(ENABLE_WD1\|ENABLE_WD2);
	199	zf_set_control(ctrl_reg);
	200	spin_unlock_irqrestore(&zf_port_lock, flags);
	201
27c766aa	202	pr_info("Watchdog timer is now disabled\n");
1da177e4 LT	203	}
	204
	205
	206	/*
	207	* start hardware timer
	208	*/
	209	static void zf_timer_on(void)
	210	{
	211	unsigned int ctrl_reg = 0;
	212	unsigned long flags;
	213
	214	spin_lock_irqsave(&zf_port_lock, flags);
	215
	216	zf_writeb(PULSE_LEN, 0xff);
	217
	218	zf_set_timer(ZF_CTIMEOUT, WD1);
	219
	220	/* user land ping */
	221	next_heartbeat = jiffies + ZF_USER_TIMEO;
	222
	223	/* start the timer for internal ping */
82eb7c50	224	mod_timer(&zf_timer, jiffies + ZF_HW_TIMEO);
1da177e4 LT	225
	226	/* start watchdog timer */
	227	ctrl_reg = zf_get_control();
	228	ctrl_reg \|= (ENABLE_WD1\|zf_action);
	229	zf_set_control(ctrl_reg);
	230	spin_unlock_irqrestore(&zf_port_lock, flags);
	231
27c766aa	232	pr_info("Watchdog timer is now enabled\n");
1da177e4 LT	233	}
	234
	235
24ed960a	236	static void zf_ping(struct timer_list *unused)
1da177e4 LT	237	{
	238	unsigned int ctrl_reg = 0;
	239	unsigned long flags;
	240
	241	zf_writeb(COUNTER_2, 0xff);
	242
325ea4d3	243	if (time_before(jiffies, next_heartbeat)) {
1da177e4	244	dprintk("time_before: %ld\n", next_heartbeat - jiffies);
1da177e4 LT	245	/*
	246	* reset event is activated by transition from 0 to 1 on
	247	* RESET_WD1 bit and we assume that it is already zero...
	248	*/
	249
	250	spin_lock_irqsave(&zf_port_lock, flags);
	251	ctrl_reg = zf_get_control();
	252	ctrl_reg \|= RESET_WD1;
	253	zf_set_control(ctrl_reg);
	254
	255	/* ...and nothing changes until here */
	256	ctrl_reg &= ~(RESET_WD1);
	257	zf_set_control(ctrl_reg);
	258	spin_unlock_irqrestore(&zf_port_lock, flags);
	259
82eb7c50	260	mod_timer(&zf_timer, jiffies + ZF_HW_TIMEO);
325ea4d3	261	} else
27c766aa	262	pr_crit("I will reset your machine\n");
1da177e4 LT	263	}
	264
	265	static ssize_t zf_write(struct file file, const char __user buf, size_t count,
	266	loff_t *ppos)
	267	{
	268	/* See if we got the magic character */
325ea4d3	269	if (count) {
1da177e4 LT	270	/*
	271	* no need to check for close confirmation
	272	* no way to disable watchdog ;)
	273	*/
	274	if (!nowayout) {
	275	size_t ofs;
1da177e4 LT	276	/*
	277	* note: just in case someone wrote the magic character
	278	* five months ago...
	279	*/
	280	zf_expect_close = 0;
	281
	282	/* now scan */
325ea4d3	283	for (ofs = 0; ofs != count; ofs++) {
1da177e4 LT	284	char c;
	285	if (get_user(c, buf + ofs))
	286	return -EFAULT;
325ea4d3	287	if (c == 'V') {
1da177e4 LT	288	zf_expect_close = 42;
	289	dprintk("zf_expect_close = 42\n");
	290	}
	291	}
	292	}
	293
	294	/*
	295	* Well, anyhow someone wrote to us,
	296	* we should return that favour
	297	*/
	298	next_heartbeat = jiffies + ZF_USER_TIMEO;
	299	dprintk("user ping at %ld\n", jiffies);
1da177e4	300	}
1da177e4 LT	301	return count;
	302	}
	303
325ea4d3	304	static long zf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1da177e4 LT	305	{
	306	void __user argp = (void __user )arg;
	307	int __user *p = argp;
bad77057 AM	308	switch (cmd) {
	309	case WDIOC_GETSUPPORT:
	310	if (copy_to_user(argp, &zf_info, sizeof(zf_info)))
	311	return -EFAULT;
	312	break;
bad77057	313	case WDIOC_GETSTATUS:
5c4eb61b	314	case WDIOC_GETBOOTSTATUS:
bad77057	315	return put_user(0, p);
bad77057	316	case WDIOC_KEEPALIVE:
33052fbb	317	zf_ping(NULL);
bad77057	318	break;
bad77057 AM	319	default:
bad77057 AM	320	return -ENOTTY;
1da177e4	321	}
1da177e4 LT	322	return 0;
	323	}
	324
	325	static int zf_open(struct inode inode, struct file file)
	326	{
325ea4d3	327	if (test_and_set_bit(0, &zf_is_open))
1da177e4	328	return -EBUSY;
1da177e4 LT	329	if (nowayout)
1da177e4 LT	330	__module_get(THIS_MODULE);
1da177e4	331	zf_timer_on();
c5bf68fe	332	return stream_open(inode, file);
1da177e4 LT	333	}
	334
	335	static int zf_close(struct inode inode, struct file file)
	336	{
325ea4d3	337	if (zf_expect_close == 42)
1da177e4	338	zf_timer_off();
325ea4d3	339	else {
1da177e4	340	del_timer(&zf_timer);
27c766aa	341	pr_err("device file closed unexpectedly. Will not stop the WDT!\n");
1da177e4	342	}
1da177e4	343	clear_bit(0, &zf_is_open);
1da177e4	344	zf_expect_close = 0;
1da177e4 LT	345	return 0;
	346	}
	347
	348	/*
	349	* Notifier for system down
	350	*/
	351
	352	static int zf_notify_sys(struct notifier_block *this, unsigned long code,
	353	void *unused)
	354	{
325ea4d3	355	if (code == SYS_DOWN \|\| code == SYS_HALT)
1da177e4	356	zf_timer_off();
1da177e4 LT	357	return NOTIFY_DONE;
	358	}
	359
62322d25	360	static const struct file_operations zf_fops = {
325ea4d3 AC	361	.owner = THIS_MODULE,
	362	.llseek = no_llseek,
	363	.write = zf_write,
	364	.unlocked_ioctl = zf_ioctl,
b6dfb247	365	.compat_ioctl = compat_ptr_ioctl,
325ea4d3 AC	366	.open = zf_open,
325ea4d3 AC	367	.release = zf_close,
1da177e4 LT	368	};
	369
	370	static struct miscdevice zf_miscdev = {
	371	.minor = WATCHDOG_MINOR,
	372	.name = "watchdog",
	373	.fops = &zf_fops,
	374	};
325ea4d3	375
1da177e4 LT	376
	377	/*
	378	* The device needs to learn about soft shutdowns in order to
	379	* turn the timebomb registers off.
	380	*/
	381	static struct notifier_block zf_notifier = {
	382	.notifier_call = zf_notify_sys,
	383	};
	384
	385	static void __init zf_show_action(int act)
	386	{
a2b89cd8	387	static const char * const str[] = { "RESET", "SMI", "NMI", "SCI" };
1da177e4	388
27c766aa	389	pr_info("Watchdog using action = %s\n", str[act]);
1da177e4 LT	390	}
	391
	392	static int __init zf_init(void)
	393	{
	394	int ret;
	395
27c766aa	396	pr_info("MachZ ZF-Logic Watchdog driver initializing\n");
1da177e4 LT	397
1da177e4 LT	398	ret = zf_get_ZFL_version();
325ea4d3	399	if (!ret \|\| ret == 0xffff) {
27c766aa	400	pr_warn("no ZF-Logic found\n");
1da177e4 LT	401	return -ENODEV;
	402	}
	403
325ea4d3 AC	404	if (action <= 3 && action >= 0)
	405	zf_action = zf_action >> action;
	406	else
1da177e4 LT	407	action = 0;
	408
	409	zf_show_action(action);
	410
325ea4d3	411	if (!request_region(ZF_IOBASE, 3, "MachZ ZFL WDT")) {
27c766aa	412	pr_err("cannot reserve I/O ports at %d\n", ZF_IOBASE);
1da177e4 LT	413	ret = -EBUSY;
	414	goto no_region;
	415	}
	416
	417	ret = register_reboot_notifier(&zf_notifier);
325ea4d3	418	if (ret) {
27c766aa	419	pr_err("can't register reboot notifier (err=%d)\n", ret);
1da177e4 LT	420	goto no_reboot;
	421	}
	422
fb8f7ba0	423	ret = misc_register(&zf_miscdev);
325ea4d3	424	if (ret) {
27c766aa	425	pr_err("can't misc_register on minor=%d\n", WATCHDOG_MINOR);
fb8f7ba0 AD	426	goto no_misc;
	427	}
	428
1da177e4 LT	429	zf_set_status(0);
	430	zf_set_control(0);
	431
1da177e4 LT	432	return 0;
1da177e4 LT	433
fb8f7ba0 AD	434	no_misc:
fb8f7ba0 AD	435	unregister_reboot_notifier(&zf_notifier);
1da177e4 LT	436	no_reboot:
	437	release_region(ZF_IOBASE, 3);
	438	no_region:
1da177e4 LT	439	return ret;
	440	}
	441
	442
	443	static void __exit zf_exit(void)
	444	{
	445	zf_timer_off();
	446
	447	misc_deregister(&zf_miscdev);
	448	unregister_reboot_notifier(&zf_notifier);
	449	release_region(ZF_IOBASE, 3);
	450	}
	451
	452	module_init(zf_init);
	453	module_exit(zf_exit);