[linux-2.6-block.git] / drivers / watchdog / w83877f_wdt.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *	W83877F Computer Watchdog Timer driver
 *
 *      Based on acquirewdt.c by Alan Cox,
 *           and sbc60xxwdt.c by Jakob Oestergaard <jakob@unthought.net>
 *
 *	The authors do 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.
 *
 *	(c) Copyright 2001    Scott Jennings <linuxdrivers@oro.net>
 *
 *           4/19 - 2001      [Initial revision]
 *           9/27 - 2001      Added spinlocking
 *           4/12 - 2002      [rob@osinvestor.com] Eliminate extra comments
 *                            Eliminate fop_read
 *                            Eliminate extra spin_unlock
 *                            Added KERN_* tags to printks
 *                            add CONFIG_WATCHDOG_NOWAYOUT support
 *                            fix possible wdt_is_open race
 *                            changed watchdog_info to correctly reflect what
 *			      the driver offers
 *                            added WDIOC_GETSTATUS, WDIOC_GETBOOTSTATUS,
 *			      WDIOC_SETTIMEOUT,
 *                            WDIOC_GETTIMEOUT, and WDIOC_SETOPTIONS ioctls
 *           09/8 - 2003      [wim@iguana.be] cleanup of trailing spaces
 *                            added extra printk's for startup problems
 *                            use module_param
 *                            made timeout (the emulated heartbeat) a
 *			      module_param
 *                            made the keepalive ping an internal subroutine
 *
 *  This WDT driver is different from most other Linux WDT
 *  drivers in that the driver will ping the watchdog by itself,
 *  because this particular WDT has a very short timeout (1.6
 *  seconds) and it would be insane to count on any userspace
 *  daemon always getting scheduled within that time frame.
 */

#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>

#define OUR_NAME "w83877f_wdt"

#define ENABLE_W83877F_PORT 0x3F0
#define ENABLE_W83877F 0x87
#define DISABLE_W83877F 0xAA
#define WDT_PING 0x443
#define WDT_REGISTER 0x14
#define WDT_ENABLE 0x9C
#define WDT_DISABLE 0x8C

/*
 * The W83877F seems to be fixed at 1.6s timeout (at least on the
 * EMACS PC-104 board I'm using). If we reset the watchdog every
 * ~250ms we should be safe.  */

#define WDT_INTERVAL (HZ/4+1)

/*
 * We must not require too good response from the userspace daemon.
 * Here we require the userspace daemon to send us a heartbeat
 * char to /dev/watchdog every 30 seconds.
 */

#define WATCHDOG_TIMEOUT 30            /* 30 sec default timeout */
/* in seconds, will be multiplied by HZ to get seconds to wait for a ping */
static int timeout = WATCHDOG_TIMEOUT;
module_param(timeout, int, 0);
MODULE_PARM_DESC(timeout,
	"Watchdog timeout in seconds. (1<=timeout<=3600, default="
				__MODULE_STRING(WATCHDOG_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 wdt_timer_ping(struct timer_list *);
static DEFINE_TIMER(timer, wdt_timer_ping);
static unsigned long next_heartbeat;
static unsigned long wdt_is_open;
static char wdt_expect_close;
static DEFINE_SPINLOCK(wdt_spinlock);

/*
 *	Whack the dog
 */

static void wdt_timer_ping(struct timer_list *unused)
{
	/* If we got a heartbeat pulse within the WDT_US_INTERVAL
	 * we agree to ping the WDT
	 */
	if (time_before(jiffies, next_heartbeat)) {
		/* Ping the WDT */
		spin_lock(&wdt_spinlock);

		/* Ping the WDT by reading from WDT_PING */
		inb_p(WDT_PING);

		/* Re-set the timer interval */
		mod_timer(&timer, jiffies + WDT_INTERVAL);

		spin_unlock(&wdt_spinlock);

	} else
		pr_warn("Heartbeat lost! Will not ping the watchdog\n");
}

/*
 * Utility routines
 */

static void wdt_change(int writeval)
{
	unsigned long flags;
	spin_lock_irqsave(&wdt_spinlock, flags);

	/* buy some time */
	inb_p(WDT_PING);

	/* make W83877F available */
	outb_p(ENABLE_W83877F,  ENABLE_W83877F_PORT);
	outb_p(ENABLE_W83877F,  ENABLE_W83877F_PORT);

	/* enable watchdog */
	outb_p(WDT_REGISTER,    ENABLE_W83877F_PORT);
	outb_p(writeval,        ENABLE_W83877F_PORT+1);

	/* lock the W8387FF away */
	outb_p(DISABLE_W83877F, ENABLE_W83877F_PORT);

	spin_unlock_irqrestore(&wdt_spinlock, flags);
}

static void wdt_startup(void)
{
	next_heartbeat = jiffies + (timeout * HZ);

	/* Start the timer */
	mod_timer(&timer, jiffies + WDT_INTERVAL);

	wdt_change(WDT_ENABLE);

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

static void wdt_turnoff(void)
{
	/* Stop the timer */
	del_timer(&timer);

	wdt_change(WDT_DISABLE);

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

static void wdt_keepalive(void)
{
	/* user land ping */
	next_heartbeat = jiffies + (timeout * HZ);
}

/*
 * /dev/watchdog handling
 */

static ssize_t fop_write(struct file *file, const char __user *buf,
						size_t count, loff_t *ppos)
{
	/* See if we got the magic character 'V' and reload the timer */
	if (count) {
		if (!nowayout) {
			size_t ofs;

			/* note: just in case someone wrote the magic
			   character five months ago... */
			wdt_expect_close = 0;

			/* scan to see whether or not we got the
			   magic character */
			for (ofs = 0; ofs != count; ofs++) {
				char c;
				if (get_user(c, buf + ofs))
					return -EFAULT;
				if (c == 'V')
					wdt_expect_close = 42;
			}
		}

		/* someone wrote to us, we should restart timer */
		wdt_keepalive();
	}
	return count;
}

static int fop_open(struct inode *inode, struct file *file)
{
	/* Just in case we're already talking to someone... */
	if (test_and_set_bit(0, &wdt_is_open))
		return -EBUSY;

	/* Good, fire up the show */
	wdt_startup();
	return stream_open(inode, file);
}

static int fop_close(struct inode *inode, struct file *file)
{
	if (wdt_expect_close == 42)
		wdt_turnoff();
	else {
		del_timer(&timer);
		pr_crit("device file closed unexpectedly. Will not stop the WDT!\n");
	}
	clear_bit(0, &wdt_is_open);
	wdt_expect_close = 0;
	return 0;
}

static long fop_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
	void __user *argp = (void __user *)arg;
	int __user *p = argp;
	static const struct watchdog_info ident = {
		.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT
							| WDIOF_MAGICCLOSE,
		.firmware_version = 1,
		.identity = "W83877F",
	};

	switch (cmd) {
	case WDIOC_GETSUPPORT:
		return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
	case WDIOC_GETSTATUS:
	case WDIOC_GETBOOTSTATUS:
		return put_user(0, p);
	case WDIOC_SETOPTIONS:
	{
		int new_options, retval = -EINVAL;

		if (get_user(new_options, p))
			return -EFAULT;

		if (new_options & WDIOS_DISABLECARD) {
			wdt_turnoff();
			retval = 0;
		}

		if (new_options & WDIOS_ENABLECARD) {
			wdt_startup();
			retval = 0;
		}

		return retval;
	}
	case WDIOC_KEEPALIVE:
		wdt_keepalive();
		return 0;
	case WDIOC_SETTIMEOUT:
	{
		int new_timeout;

		if (get_user(new_timeout, p))
			return -EFAULT;

		/* arbitrary upper limit */
		if (new_timeout < 1 || new_timeout > 3600)
			return -EINVAL;

		timeout = new_timeout;
		wdt_keepalive();
	}
		/* Fall through */
	case WDIOC_GETTIMEOUT:
		return put_user(timeout, p);
	default:
		return -ENOTTY;
	}
}

static const struct file_operations wdt_fops = {
	.owner		= THIS_MODULE,
	.llseek		= no_llseek,
	.write		= fop_write,
	.open		= fop_open,
	.release	= fop_close,
	.unlocked_ioctl	= fop_ioctl,
};

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

/*
 *	Notifier for system down
 */

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

/*
 *	The WDT needs to learn about soft shutdowns in order to
 *	turn the timebomb registers off.
 */

static struct notifier_block wdt_notifier = {
	.notifier_call = wdt_notify_sys,
};

static void __exit w83877f_wdt_unload(void)
{
	wdt_turnoff();

	/* Deregister */
	misc_deregister(&wdt_miscdev);

	unregister_reboot_notifier(&wdt_notifier);
	release_region(WDT_PING, 1);
	release_region(ENABLE_W83877F_PORT, 2);
}

static int __init w83877f_wdt_init(void)
{
	int rc = -EBUSY;

	if (timeout < 1 || timeout > 3600) { /* arbitrary upper limit */
		timeout = WATCHDOG_TIMEOUT;
		pr_info("timeout value must be 1 <= x <= 3600, using %d\n",
			timeout);
	}

	if (!request_region(ENABLE_W83877F_PORT, 2, "W83877F WDT")) {
		pr_err("I/O address 0x%04x already in use\n",
		       ENABLE_W83877F_PORT);
		rc = -EIO;
		goto err_out;
	}

	if (!request_region(WDT_PING, 1, "W8387FF WDT")) {
		pr_err("I/O address 0x%04x already in use\n", WDT_PING);
		rc = -EIO;
		goto err_out_region1;
	}

	rc = register_reboot_notifier(&wdt_notifier);
	if (rc) {
		pr_err("cannot register reboot notifier (err=%d)\n", rc);
		goto err_out_region2;
	}

	rc = misc_register(&wdt_miscdev);
	if (rc) {
		pr_err("cannot register miscdev on minor=%d (err=%d)\n",
		       wdt_miscdev.minor, rc);
		goto err_out_reboot;
	}

	pr_info("WDT driver for W83877F initialised. timeout=%d sec (nowayout=%d)\n",
		timeout, nowayout);

	return 0;

err_out_reboot:
	unregister_reboot_notifier(&wdt_notifier);
err_out_region2:
	release_region(WDT_PING, 1);
err_out_region1:
	release_region(ENABLE_W83877F_PORT, 2);
err_out:
	return rc;
}

module_init(w83877f_wdt_init);
module_exit(w83877f_wdt_unload);

MODULE_AUTHOR("Scott and Bill Jennings");
MODULE_DESCRIPTION("Driver for watchdog timer in w83877f chip");
MODULE_LICENSE("GPL");
Commit	Line	Data
2874c5fd	1	// SPDX-License-Identifier: GPL-2.0-or-later
1da177e4 LT	2	/*
	3	* W83877F Computer Watchdog Timer driver
	4	*
	5	* Based on acquirewdt.c by Alan Cox,
	6	* and sbc60xxwdt.c by Jakob Oestergaard <jakob@unthought.net>
	7	*
1da177e4 LT	8	* The authors do NOT admit liability nor provide warranty for
	9	* any of this software. This material is provided "AS-IS" in
	10	* the hope that it may be useful for others.
	11	*
	12	* (c) Copyright 2001 Scott Jennings <linuxdrivers@oro.net>
	13	*
	14	* 4/19 - 2001 [Initial revision]
	15	* 9/27 - 2001 Added spinlocking
	16	* 4/12 - 2002 [rob@osinvestor.com] Eliminate extra comments
	17	* Eliminate fop_read
	18	* Eliminate extra spin_unlock
	19	* Added KERN_* tags to printks
	20	* add CONFIG_WATCHDOG_NOWAYOUT support
	21	* fix possible wdt_is_open race
c1cfd1a2 AC	22	* changed watchdog_info to correctly reflect what
	23	* the driver offers
	24	* added WDIOC_GETSTATUS, WDIOC_GETBOOTSTATUS,
	25	* WDIOC_SETTIMEOUT,
1da177e4 LT	26	* WDIOC_GETTIMEOUT, and WDIOC_SETOPTIONS ioctls
	27	* 09/8 - 2003 [wim@iguana.be] cleanup of trailing spaces
	28	* added extra printk's for startup problems
	29	* use module_param
c1cfd1a2 AC	30	* made timeout (the emulated heartbeat) a
c1cfd1a2 AC	31	* module_param
1da177e4 LT	32	* made the keepalive ping an internal subroutine
	33	*
	34	* This WDT driver is different from most other Linux WDT
	35	* drivers in that the driver will ping the watchdog by itself,
	36	* because this particular WDT has a very short timeout (1.6
	37	* seconds) and it would be insane to count on any userspace
	38	* daemon always getting scheduled within that time frame.
	39	*/
	40
27c766aa JP	41	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
27c766aa JP	42
1da177e4 LT	43	#include <linux/module.h>
	44	#include <linux/moduleparam.h>
	45	#include <linux/types.h>
	46	#include <linux/timer.h>
	47	#include <linux/jiffies.h>
	48	#include <linux/miscdevice.h>
	49	#include <linux/watchdog.h>
	50	#include <linux/fs.h>
	51	#include <linux/ioport.h>
	52	#include <linux/notifier.h>
	53	#include <linux/reboot.h>
	54	#include <linux/init.h>
c1cfd1a2 AC	55	#include <linux/io.h>
c1cfd1a2 AC	56	#include <linux/uaccess.h>
1da177e4 LT	57
1da177e4 LT	58	#define OUR_NAME "w83877f_wdt"
1da177e4 LT	59
	60	#define ENABLE_W83877F_PORT 0x3F0
	61	#define ENABLE_W83877F 0x87
	62	#define DISABLE_W83877F 0xAA
	63	#define WDT_PING 0x443
	64	#define WDT_REGISTER 0x14
	65	#define WDT_ENABLE 0x9C
	66	#define WDT_DISABLE 0x8C
	67
	68	/*
	69	* The W83877F seems to be fixed at 1.6s timeout (at least on the
	70	* EMACS PC-104 board I'm using). If we reset the watchdog every
	71	* ~250ms we should be safe. */
	72
	73	#define WDT_INTERVAL (HZ/4+1)
	74
	75	/*
	76	* We must not require too good response from the userspace daemon.
	77	* Here we require the userspace daemon to send us a heartbeat
	78	* char to /dev/watchdog every 30 seconds.
	79	*/
	80
	81	#define WATCHDOG_TIMEOUT 30 /* 30 sec default timeout */
c1cfd1a2 AC	82	/* in seconds, will be multiplied by HZ to get seconds to wait for a ping */
c1cfd1a2 AC	83	static int timeout = WATCHDOG_TIMEOUT;
1da177e4	84	module_param(timeout, int, 0);
c1cfd1a2 AC	85	MODULE_PARM_DESC(timeout,
	86	"Watchdog timeout in seconds. (1<=timeout<=3600, default="
	87	__MODULE_STRING(WATCHDOG_TIMEOUT) ")");
1da177e4 LT	88
1da177e4 LT	89
86a1e189 WVS	90	static bool nowayout = WATCHDOG_NOWAYOUT;
86a1e189 WVS	91	module_param(nowayout, bool, 0);
c1cfd1a2 AC	92	MODULE_PARM_DESC(nowayout,
	93	"Watchdog cannot be stopped once started (default="
	94	__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
1da177e4	95
24ed960a	96	static void wdt_timer_ping(struct timer_list *);
1d27e3e2	97	static DEFINE_TIMER(timer, wdt_timer_ping);
1da177e4 LT	98	static unsigned long next_heartbeat;
	99	static unsigned long wdt_is_open;
	100	static char wdt_expect_close;
c7dfd0cc	101	static DEFINE_SPINLOCK(wdt_spinlock);
1da177e4 LT	102
	103	/*
	104	* Whack the dog
	105	*/
	106
24ed960a	107	static void wdt_timer_ping(struct timer_list *unused)
1da177e4 LT	108	{
	109	/* If we got a heartbeat pulse within the WDT_US_INTERVAL
	110	* we agree to ping the WDT
	111	*/
c1cfd1a2	112	if (time_before(jiffies, next_heartbeat)) {
1da177e4 LT	113	/* Ping the WDT */
	114	spin_lock(&wdt_spinlock);
	115
	116	/* Ping the WDT by reading from WDT_PING */
	117	inb_p(WDT_PING);
	118
	119	/* Re-set the timer interval */
82eb7c50	120	mod_timer(&timer, jiffies + WDT_INTERVAL);
1da177e4 LT	121
	122	spin_unlock(&wdt_spinlock);
	123
c1cfd1a2	124	} else
27c766aa	125	pr_warn("Heartbeat lost! Will not ping the watchdog\n");
1da177e4 LT	126	}
	127
	128	/*
	129	* Utility routines
	130	*/
	131
	132	static void wdt_change(int writeval)
	133	{
	134	unsigned long flags;
	135	spin_lock_irqsave(&wdt_spinlock, flags);
	136
	137	/* buy some time */
	138	inb_p(WDT_PING);
	139
	140	/* make W83877F available */
	141	outb_p(ENABLE_W83877F, ENABLE_W83877F_PORT);
	142	outb_p(ENABLE_W83877F, ENABLE_W83877F_PORT);
	143
	144	/* enable watchdog */
	145	outb_p(WDT_REGISTER, ENABLE_W83877F_PORT);
	146	outb_p(writeval, ENABLE_W83877F_PORT+1);
	147
	148	/* lock the W8387FF away */
	149	outb_p(DISABLE_W83877F, ENABLE_W83877F_PORT);
	150
	151	spin_unlock_irqrestore(&wdt_spinlock, flags);
	152	}
	153
	154	static void wdt_startup(void)
	155	{
	156	next_heartbeat = jiffies + (timeout * HZ);
	157
	158	/* Start the timer */
82eb7c50	159	mod_timer(&timer, jiffies + WDT_INTERVAL);
1da177e4 LT	160
	161	wdt_change(WDT_ENABLE);
	162
27c766aa	163	pr_info("Watchdog timer is now enabled\n");
1da177e4 LT	164	}
	165
	166	static void wdt_turnoff(void)
	167	{
	168	/* Stop the timer */
	169	del_timer(&timer);
	170
	171	wdt_change(WDT_DISABLE);
	172
27c766aa	173	pr_info("Watchdog timer is now disabled...\n");
1da177e4 LT	174	}
	175
	176	static void wdt_keepalive(void)
	177	{
	178	/* user land ping */
	179	next_heartbeat = jiffies + (timeout * HZ);
	180	}
	181
	182	/*
	183	* /dev/watchdog handling
	184	*/
	185
c1cfd1a2 AC	186	static ssize_t fop_write(struct file file, const char __user buf,
c1cfd1a2 AC	187	size_t count, loff_t *ppos)
1da177e4 LT	188	{
1da177e4 LT	189	/* See if we got the magic character 'V' and reload the timer */
c1cfd1a2 AC	190	if (count) {
c1cfd1a2 AC	191	if (!nowayout) {
1da177e4 LT	192	size_t ofs;
1da177e4 LT	193
c1cfd1a2 AC	194	/* note: just in case someone wrote the magic
c1cfd1a2 AC	195	character five months ago... */
1da177e4 LT	196	wdt_expect_close = 0;
1da177e4 LT	197
c1cfd1a2 AC	198	/* scan to see whether or not we got the
	199	magic character */
	200	for (ofs = 0; ofs != count; ofs++) {
1da177e4 LT	201	char c;
	202	if (get_user(c, buf + ofs))
	203	return -EFAULT;
	204	if (c == 'V')
	205	wdt_expect_close = 42;
	206	}
	207	}
	208
	209	/* someone wrote to us, we should restart timer */
	210	wdt_keepalive();
	211	}
	212	return count;
	213	}
	214
c1cfd1a2	215	static int fop_open(struct inode inode, struct file file)
1da177e4 LT	216	{
1da177e4 LT	217	/* Just in case we're already talking to someone... */
c1cfd1a2	218	if (test_and_set_bit(0, &wdt_is_open))
1da177e4 LT	219	return -EBUSY;
	220
	221	/* Good, fire up the show */
	222	wdt_startup();
c5bf68fe	223	return stream_open(inode, file);
1da177e4 LT	224	}
1da177e4 LT	225
c1cfd1a2	226	static int fop_close(struct inode inode, struct file file)
1da177e4	227	{
c1cfd1a2	228	if (wdt_expect_close == 42)
1da177e4 LT	229	wdt_turnoff();
	230	else {
	231	del_timer(&timer);
27c766aa	232	pr_crit("device file closed unexpectedly. Will not stop the WDT!\n");
1da177e4 LT	233	}
	234	clear_bit(0, &wdt_is_open);
	235	wdt_expect_close = 0;
	236	return 0;
	237	}
	238
c1cfd1a2	239	static long fop_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1da177e4 LT	240	{
	241	void __user argp = (void __user )arg;
	242	int __user *p = argp;
c1cfd1a2 AC	243	static const struct watchdog_info ident = {
	244	.options = WDIOF_KEEPALIVEPING \| WDIOF_SETTIMEOUT
	245	\| WDIOF_MAGICCLOSE,
1da177e4 LT	246	.firmware_version = 1,
	247	.identity = "W83877F",
	248	};
	249
c1cfd1a2	250	switch (cmd) {
c1cfd1a2 AC	251	case WDIOC_GETSUPPORT:
	252	return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
	253	case WDIOC_GETSTATUS:
	254	case WDIOC_GETBOOTSTATUS:
	255	return put_user(0, p);
c1cfd1a2	256	case WDIOC_SETOPTIONS:
1da177e4	257	{
c1cfd1a2	258	int new_options, retval = -EINVAL;
1da177e4	259
c1cfd1a2 AC	260	if (get_user(new_options, p))
c1cfd1a2 AC	261	return -EFAULT;
1da177e4	262
c1cfd1a2 AC	263	if (new_options & WDIOS_DISABLECARD) {
	264	wdt_turnoff();
	265	retval = 0;
1da177e4	266	}
1da177e4	267
c1cfd1a2 AC	268	if (new_options & WDIOS_ENABLECARD) {
	269	wdt_startup();
	270	retval = 0;
	271	}
1da177e4	272
c1cfd1a2 AC	273	return retval;
c1cfd1a2 AC	274	}
0c06090c WVS	275	case WDIOC_KEEPALIVE:
	276	wdt_keepalive();
	277	return 0;
c1cfd1a2 AC	278	case WDIOC_SETTIMEOUT:
	279	{
	280	int new_timeout;
1da177e4	281
c1cfd1a2 AC	282	if (get_user(new_timeout, p))
	283	return -EFAULT;
	284
	285	/* arbitrary upper limit */
	286	if (new_timeout < 1 \|\| new_timeout > 3600)
	287	return -EINVAL;
	288
	289	timeout = new_timeout;
	290	wdt_keepalive();
c1cfd1a2	291	}
458c8961	292	/* Fall through */
c1cfd1a2 AC	293	case WDIOC_GETTIMEOUT:
c1cfd1a2 AC	294	return put_user(timeout, p);
0c06090c WVS	295	default:
0c06090c WVS	296	return -ENOTTY;
1da177e4 LT	297	}
	298	}
	299
62322d25	300	static const struct file_operations wdt_fops = {
1da177e4 LT	301	.owner = THIS_MODULE,
	302	.llseek = no_llseek,
	303	.write = fop_write,
	304	.open = fop_open,
	305	.release = fop_close,
c1cfd1a2	306	.unlocked_ioctl = fop_ioctl,
1da177e4 LT	307	};
	308
	309	static struct miscdevice wdt_miscdev = {
	310	.minor = WATCHDOG_MINOR,
	311	.name = "watchdog",
	312	.fops = &wdt_fops,
	313	};
	314
	315	/*
	316	* Notifier for system down
	317	*/
	318
	319	static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
	320	void *unused)
	321	{
c1cfd1a2	322	if (code == SYS_DOWN \|\| code == SYS_HALT)
1da177e4 LT	323	wdt_turnoff();
	324	return NOTIFY_DONE;
	325	}
	326
	327	/*
	328	* The WDT needs to learn about soft shutdowns in order to
	329	* turn the timebomb registers off.
	330	*/
	331
c1cfd1a2	332	static struct notifier_block wdt_notifier = {
1da177e4 LT	333	.notifier_call = wdt_notify_sys,
	334	};
	335
	336	static void __exit w83877f_wdt_unload(void)
	337	{
	338	wdt_turnoff();
	339
	340	/* Deregister */
	341	misc_deregister(&wdt_miscdev);
	342
	343	unregister_reboot_notifier(&wdt_notifier);
c1cfd1a2 AC	344	release_region(WDT_PING, 1);
c1cfd1a2 AC	345	release_region(ENABLE_W83877F_PORT, 2);
1da177e4 LT	346	}
	347
	348	static int __init w83877f_wdt_init(void)
	349	{
	350	int rc = -EBUSY;
	351
c1cfd1a2	352	if (timeout < 1 \|\| timeout > 3600) { /* arbitrary upper limit */
1da177e4	353	timeout = WATCHDOG_TIMEOUT;
27c766aa JP	354	pr_info("timeout value must be 1 <= x <= 3600, using %d\n",
27c766aa JP	355	timeout);
1da177e4 LT	356	}
1da177e4 LT	357
c1cfd1a2	358	if (!request_region(ENABLE_W83877F_PORT, 2, "W83877F WDT")) {
27c766aa JP	359	pr_err("I/O address 0x%04x already in use\n",
27c766aa JP	360	ENABLE_W83877F_PORT);
1da177e4 LT	361	rc = -EIO;
	362	goto err_out;
	363	}
	364
c1cfd1a2	365	if (!request_region(WDT_PING, 1, "W8387FF WDT")) {
27c766aa	366	pr_err("I/O address 0x%04x already in use\n", WDT_PING);
1da177e4 LT	367	rc = -EIO;
	368	goto err_out_region1;
	369	}
	370
c6cb13ae	371	rc = register_reboot_notifier(&wdt_notifier);
c1cfd1a2	372	if (rc) {
27c766aa	373	pr_err("cannot register reboot notifier (err=%d)\n", rc);
1da177e4 LT	374	goto err_out_region2;
	375	}
	376
c6cb13ae	377	rc = misc_register(&wdt_miscdev);
c1cfd1a2	378	if (rc) {
27c766aa JP	379	pr_err("cannot register miscdev on minor=%d (err=%d)\n",
27c766aa JP	380	wdt_miscdev.minor, rc);
c6cb13ae	381	goto err_out_reboot;
1da177e4 LT	382	}
1da177e4 LT	383
27c766aa	384	pr_info("WDT driver for W83877F initialised. timeout=%d sec (nowayout=%d)\n",
1da177e4 LT	385	timeout, nowayout);
	386
	387	return 0;
	388
c6cb13ae WVS	389	err_out_reboot:
c6cb13ae WVS	390	unregister_reboot_notifier(&wdt_notifier);
1da177e4	391	err_out_region2:
c1cfd1a2	392	release_region(WDT_PING, 1);
1da177e4	393	err_out_region1:
c1cfd1a2	394	release_region(ENABLE_W83877F_PORT, 2);
1da177e4 LT	395	err_out:
	396	return rc;
	397	}
	398
	399	module_init(w83877f_wdt_init);
	400	module_exit(w83877f_wdt_unload);
	401
	402	MODULE_AUTHOR("Scott and Bill Jennings");
	403	MODULE_DESCRIPTION("Driver for watchdog timer in w83877f chip");
	404	MODULE_LICENSE("GPL");