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v6.9.4
  1// SPDX-License-Identifier: GPL-2.0-or-later
  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 *
 
 
 
 
 
  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
 22 *                            changed watchdog_info to correctly reflect what
 23 *			      the driver offers
 24 *                            added WDIOC_GETSTATUS, WDIOC_GETBOOTSTATUS,
 25 *			      WDIOC_SETTIMEOUT,
 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
 30 *                            made timeout (the emulated heartbeat) a
 31 *			      module_param
 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
 41#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 42
 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>
 55#include <linux/io.h>
 56#include <linux/uaccess.h>
 57
 58#define OUR_NAME "w83877f_wdt"
 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 */
 82/* in seconds, will be multiplied by HZ to get seconds to wait for a ping */
 83static int timeout = WATCHDOG_TIMEOUT;
 84module_param(timeout, int, 0);
 85MODULE_PARM_DESC(timeout,
 86	"Watchdog timeout in seconds. (1<=timeout<=3600, default="
 87				__MODULE_STRING(WATCHDOG_TIMEOUT) ")");
 88
 89
 90static bool nowayout = WATCHDOG_NOWAYOUT;
 91module_param(nowayout, bool, 0);
 92MODULE_PARM_DESC(nowayout,
 93		"Watchdog cannot be stopped once started (default="
 94				__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
 95
 96static void wdt_timer_ping(struct timer_list *);
 97static DEFINE_TIMER(timer, wdt_timer_ping);
 98static unsigned long next_heartbeat;
 99static unsigned long wdt_is_open;
100static char wdt_expect_close;
101static DEFINE_SPINLOCK(wdt_spinlock);
102
103/*
104 *	Whack the dog
105 */
106
107static void wdt_timer_ping(struct timer_list *unused)
108{
109	/* If we got a heartbeat pulse within the WDT_US_INTERVAL
110	 * we agree to ping the WDT
111	 */
112	if (time_before(jiffies, next_heartbeat)) {
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 */
120		mod_timer(&timer, jiffies + WDT_INTERVAL);
121
122		spin_unlock(&wdt_spinlock);
123
124	} else
125		pr_warn("Heartbeat lost! Will not ping the watchdog\n");
126}
127
128/*
129 * Utility routines
130 */
131
132static 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
154static void wdt_startup(void)
155{
156	next_heartbeat = jiffies + (timeout * HZ);
157
158	/* Start the timer */
159	mod_timer(&timer, jiffies + WDT_INTERVAL);
160
161	wdt_change(WDT_ENABLE);
162
163	pr_info("Watchdog timer is now enabled\n");
164}
165
166static void wdt_turnoff(void)
167{
168	/* Stop the timer */
169	del_timer_sync(&timer);
170
171	wdt_change(WDT_DISABLE);
172
173	pr_info("Watchdog timer is now disabled...\n");
174}
175
176static void wdt_keepalive(void)
177{
178	/* user land ping */
179	next_heartbeat = jiffies + (timeout * HZ);
180}
181
182/*
183 * /dev/watchdog handling
184 */
185
186static ssize_t fop_write(struct file *file, const char __user *buf,
187						size_t count, loff_t *ppos)
188{
189	/* See if we got the magic character 'V' and reload the timer */
190	if (count) {
191		if (!nowayout) {
192			size_t ofs;
193
194			/* note: just in case someone wrote the magic
195			   character five months ago... */
196			wdt_expect_close = 0;
197
198			/* scan to see whether or not we got the
199			   magic character */
200			for (ofs = 0; ofs != count; ofs++) {
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
215static int fop_open(struct inode *inode, struct file *file)
216{
217	/* Just in case we're already talking to someone... */
218	if (test_and_set_bit(0, &wdt_is_open))
219		return -EBUSY;
220
221	/* Good, fire up the show */
222	wdt_startup();
223	return stream_open(inode, file);
224}
225
226static int fop_close(struct inode *inode, struct file *file)
227{
228	if (wdt_expect_close == 42)
229		wdt_turnoff();
230	else {
231		del_timer(&timer);
232		pr_crit("device file closed unexpectedly. Will not stop the WDT!\n");
233	}
234	clear_bit(0, &wdt_is_open);
235	wdt_expect_close = 0;
236	return 0;
237}
238
239static long fop_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
240{
241	void __user *argp = (void __user *)arg;
242	int __user *p = argp;
243	static const struct watchdog_info ident = {
244		.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT
245							| WDIOF_MAGICCLOSE,
246		.firmware_version = 1,
247		.identity = "W83877F",
248	};
249
250	switch (cmd) {
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);
256	case WDIOC_SETOPTIONS:
257	{
258		int new_options, retval = -EINVAL;
259
260		if (get_user(new_options, p))
261			return -EFAULT;
262
263		if (new_options & WDIOS_DISABLECARD) {
264			wdt_turnoff();
265			retval = 0;
266		}
267
268		if (new_options & WDIOS_ENABLECARD) {
269			wdt_startup();
270			retval = 0;
271		}
272
273		return retval;
274	}
275	case WDIOC_KEEPALIVE:
276		wdt_keepalive();
277		return 0;
278	case WDIOC_SETTIMEOUT:
279	{
280		int new_timeout;
281
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();
 
291	}
292		fallthrough;
293	case WDIOC_GETTIMEOUT:
294		return put_user(timeout, p);
295	default:
296		return -ENOTTY;
297	}
298}
299
300static const struct file_operations wdt_fops = {
301	.owner		= THIS_MODULE,
302	.llseek		= no_llseek,
303	.write		= fop_write,
304	.open		= fop_open,
305	.release	= fop_close,
306	.unlocked_ioctl	= fop_ioctl,
307	.compat_ioctl	= compat_ptr_ioctl,
308};
309
310static struct miscdevice wdt_miscdev = {
311	.minor	= WATCHDOG_MINOR,
312	.name	= "watchdog",
313	.fops	= &wdt_fops,
314};
315
316/*
317 *	Notifier for system down
318 */
319
320static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
321	void *unused)
322{
323	if (code == SYS_DOWN || code == SYS_HALT)
324		wdt_turnoff();
325	return NOTIFY_DONE;
326}
327
328/*
329 *	The WDT needs to learn about soft shutdowns in order to
330 *	turn the timebomb registers off.
331 */
332
333static struct notifier_block wdt_notifier = {
334	.notifier_call = wdt_notify_sys,
335};
336
337static void __exit w83877f_wdt_unload(void)
338{
339	wdt_turnoff();
340
341	/* Deregister */
342	misc_deregister(&wdt_miscdev);
343
344	unregister_reboot_notifier(&wdt_notifier);
345	release_region(WDT_PING, 1);
346	release_region(ENABLE_W83877F_PORT, 2);
347}
348
349static int __init w83877f_wdt_init(void)
350{
351	int rc = -EBUSY;
352
353	if (timeout < 1 || timeout > 3600) { /* arbitrary upper limit */
354		timeout = WATCHDOG_TIMEOUT;
355		pr_info("timeout value must be 1 <= x <= 3600, using %d\n",
356			timeout);
357	}
358
359	if (!request_region(ENABLE_W83877F_PORT, 2, "W83877F WDT")) {
360		pr_err("I/O address 0x%04x already in use\n",
361		       ENABLE_W83877F_PORT);
362		rc = -EIO;
363		goto err_out;
364	}
365
366	if (!request_region(WDT_PING, 1, "W8387FF WDT")) {
367		pr_err("I/O address 0x%04x already in use\n", WDT_PING);
368		rc = -EIO;
369		goto err_out_region1;
370	}
371
372	rc = register_reboot_notifier(&wdt_notifier);
373	if (rc) {
374		pr_err("cannot register reboot notifier (err=%d)\n", rc);
375		goto err_out_region2;
376	}
377
378	rc = misc_register(&wdt_miscdev);
379	if (rc) {
380		pr_err("cannot register miscdev on minor=%d (err=%d)\n",
381		       wdt_miscdev.minor, rc);
382		goto err_out_reboot;
383	}
384
385	pr_info("WDT driver for W83877F initialised. timeout=%d sec (nowayout=%d)\n",
386		timeout, nowayout);
387
388	return 0;
389
390err_out_reboot:
391	unregister_reboot_notifier(&wdt_notifier);
392err_out_region2:
393	release_region(WDT_PING, 1);
394err_out_region1:
395	release_region(ENABLE_W83877F_PORT, 2);
396err_out:
397	return rc;
398}
399
400module_init(w83877f_wdt_init);
401module_exit(w83877f_wdt_unload);
402
403MODULE_AUTHOR("Scott and Bill Jennings");
404MODULE_DESCRIPTION("Driver for watchdog timer in w83877f chip");
405MODULE_LICENSE("GPL");
v4.17
 
  1/*
  2 *	W83877F Computer Watchdog Timer driver
  3 *
  4 *      Based on acquirewdt.c by Alan Cox,
  5 *           and sbc60xxwdt.c by Jakob Oestergaard <jakob@unthought.net>
  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 *	The authors do NOT admit liability nor provide warranty for
 13 *	any of this software. This material is provided "AS-IS" in
 14 *      the hope that it may be useful for others.
 15 *
 16 *	(c) Copyright 2001    Scott Jennings <linuxdrivers@oro.net>
 17 *
 18 *           4/19 - 2001      [Initial revision]
 19 *           9/27 - 2001      Added spinlocking
 20 *           4/12 - 2002      [rob@osinvestor.com] Eliminate extra comments
 21 *                            Eliminate fop_read
 22 *                            Eliminate extra spin_unlock
 23 *                            Added KERN_* tags to printks
 24 *                            add CONFIG_WATCHDOG_NOWAYOUT support
 25 *                            fix possible wdt_is_open race
 26 *                            changed watchdog_info to correctly reflect what
 27 *			      the driver offers
 28 *                            added WDIOC_GETSTATUS, WDIOC_GETBOOTSTATUS,
 29 *			      WDIOC_SETTIMEOUT,
 30 *                            WDIOC_GETTIMEOUT, and WDIOC_SETOPTIONS ioctls
 31 *           09/8 - 2003      [wim@iguana.be] cleanup of trailing spaces
 32 *                            added extra printk's for startup problems
 33 *                            use module_param
 34 *                            made timeout (the emulated heartbeat) a
 35 *			      module_param
 36 *                            made the keepalive ping an internal subroutine
 37 *
 38 *  This WDT driver is different from most other Linux WDT
 39 *  drivers in that the driver will ping the watchdog by itself,
 40 *  because this particular WDT has a very short timeout (1.6
 41 *  seconds) and it would be insane to count on any userspace
 42 *  daemon always getting scheduled within that time frame.
 43 */
 44
 45#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 46
 47#include <linux/module.h>
 48#include <linux/moduleparam.h>
 49#include <linux/types.h>
 50#include <linux/timer.h>
 51#include <linux/jiffies.h>
 52#include <linux/miscdevice.h>
 53#include <linux/watchdog.h>
 54#include <linux/fs.h>
 55#include <linux/ioport.h>
 56#include <linux/notifier.h>
 57#include <linux/reboot.h>
 58#include <linux/init.h>
 59#include <linux/io.h>
 60#include <linux/uaccess.h>
 61
 62#define OUR_NAME "w83877f_wdt"
 63
 64#define ENABLE_W83877F_PORT 0x3F0
 65#define ENABLE_W83877F 0x87
 66#define DISABLE_W83877F 0xAA
 67#define WDT_PING 0x443
 68#define WDT_REGISTER 0x14
 69#define WDT_ENABLE 0x9C
 70#define WDT_DISABLE 0x8C
 71
 72/*
 73 * The W83877F seems to be fixed at 1.6s timeout (at least on the
 74 * EMACS PC-104 board I'm using). If we reset the watchdog every
 75 * ~250ms we should be safe.  */
 76
 77#define WDT_INTERVAL (HZ/4+1)
 78
 79/*
 80 * We must not require too good response from the userspace daemon.
 81 * Here we require the userspace daemon to send us a heartbeat
 82 * char to /dev/watchdog every 30 seconds.
 83 */
 84
 85#define WATCHDOG_TIMEOUT 30            /* 30 sec default timeout */
 86/* in seconds, will be multiplied by HZ to get seconds to wait for a ping */
 87static int timeout = WATCHDOG_TIMEOUT;
 88module_param(timeout, int, 0);
 89MODULE_PARM_DESC(timeout,
 90	"Watchdog timeout in seconds. (1<=timeout<=3600, default="
 91				__MODULE_STRING(WATCHDOG_TIMEOUT) ")");
 92
 93
 94static bool nowayout = WATCHDOG_NOWAYOUT;
 95module_param(nowayout, bool, 0);
 96MODULE_PARM_DESC(nowayout,
 97		"Watchdog cannot be stopped once started (default="
 98				__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
 99
100static void wdt_timer_ping(struct timer_list *);
101static DEFINE_TIMER(timer, wdt_timer_ping);
102static unsigned long next_heartbeat;
103static unsigned long wdt_is_open;
104static char wdt_expect_close;
105static DEFINE_SPINLOCK(wdt_spinlock);
106
107/*
108 *	Whack the dog
109 */
110
111static void wdt_timer_ping(struct timer_list *unused)
112{
113	/* If we got a heartbeat pulse within the WDT_US_INTERVAL
114	 * we agree to ping the WDT
115	 */
116	if (time_before(jiffies, next_heartbeat)) {
117		/* Ping the WDT */
118		spin_lock(&wdt_spinlock);
119
120		/* Ping the WDT by reading from WDT_PING */
121		inb_p(WDT_PING);
122
123		/* Re-set the timer interval */
124		mod_timer(&timer, jiffies + WDT_INTERVAL);
125
126		spin_unlock(&wdt_spinlock);
127
128	} else
129		pr_warn("Heartbeat lost! Will not ping the watchdog\n");
130}
131
132/*
133 * Utility routines
134 */
135
136static void wdt_change(int writeval)
137{
138	unsigned long flags;
139	spin_lock_irqsave(&wdt_spinlock, flags);
140
141	/* buy some time */
142	inb_p(WDT_PING);
143
144	/* make W83877F available */
145	outb_p(ENABLE_W83877F,  ENABLE_W83877F_PORT);
146	outb_p(ENABLE_W83877F,  ENABLE_W83877F_PORT);
147
148	/* enable watchdog */
149	outb_p(WDT_REGISTER,    ENABLE_W83877F_PORT);
150	outb_p(writeval,        ENABLE_W83877F_PORT+1);
151
152	/* lock the W8387FF away */
153	outb_p(DISABLE_W83877F, ENABLE_W83877F_PORT);
154
155	spin_unlock_irqrestore(&wdt_spinlock, flags);
156}
157
158static void wdt_startup(void)
159{
160	next_heartbeat = jiffies + (timeout * HZ);
161
162	/* Start the timer */
163	mod_timer(&timer, jiffies + WDT_INTERVAL);
164
165	wdt_change(WDT_ENABLE);
166
167	pr_info("Watchdog timer is now enabled\n");
168}
169
170static void wdt_turnoff(void)
171{
172	/* Stop the timer */
173	del_timer(&timer);
174
175	wdt_change(WDT_DISABLE);
176
177	pr_info("Watchdog timer is now disabled...\n");
178}
179
180static void wdt_keepalive(void)
181{
182	/* user land ping */
183	next_heartbeat = jiffies + (timeout * HZ);
184}
185
186/*
187 * /dev/watchdog handling
188 */
189
190static ssize_t fop_write(struct file *file, const char __user *buf,
191						size_t count, loff_t *ppos)
192{
193	/* See if we got the magic character 'V' and reload the timer */
194	if (count) {
195		if (!nowayout) {
196			size_t ofs;
197
198			/* note: just in case someone wrote the magic
199			   character five months ago... */
200			wdt_expect_close = 0;
201
202			/* scan to see whether or not we got the
203			   magic character */
204			for (ofs = 0; ofs != count; ofs++) {
205				char c;
206				if (get_user(c, buf + ofs))
207					return -EFAULT;
208				if (c == 'V')
209					wdt_expect_close = 42;
210			}
211		}
212
213		/* someone wrote to us, we should restart timer */
214		wdt_keepalive();
215	}
216	return count;
217}
218
219static int fop_open(struct inode *inode, struct file *file)
220{
221	/* Just in case we're already talking to someone... */
222	if (test_and_set_bit(0, &wdt_is_open))
223		return -EBUSY;
224
225	/* Good, fire up the show */
226	wdt_startup();
227	return nonseekable_open(inode, file);
228}
229
230static int fop_close(struct inode *inode, struct file *file)
231{
232	if (wdt_expect_close == 42)
233		wdt_turnoff();
234	else {
235		del_timer(&timer);
236		pr_crit("device file closed unexpectedly. Will not stop the WDT!\n");
237	}
238	clear_bit(0, &wdt_is_open);
239	wdt_expect_close = 0;
240	return 0;
241}
242
243static long fop_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
244{
245	void __user *argp = (void __user *)arg;
246	int __user *p = argp;
247	static const struct watchdog_info ident = {
248		.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT
249							| WDIOF_MAGICCLOSE,
250		.firmware_version = 1,
251		.identity = "W83877F",
252	};
253
254	switch (cmd) {
255	case WDIOC_GETSUPPORT:
256		return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
257	case WDIOC_GETSTATUS:
258	case WDIOC_GETBOOTSTATUS:
259		return put_user(0, p);
260	case WDIOC_SETOPTIONS:
261	{
262		int new_options, retval = -EINVAL;
263
264		if (get_user(new_options, p))
265			return -EFAULT;
266
267		if (new_options & WDIOS_DISABLECARD) {
268			wdt_turnoff();
269			retval = 0;
270		}
271
272		if (new_options & WDIOS_ENABLECARD) {
273			wdt_startup();
274			retval = 0;
275		}
276
277		return retval;
278	}
279	case WDIOC_KEEPALIVE:
280		wdt_keepalive();
281		return 0;
282	case WDIOC_SETTIMEOUT:
283	{
284		int new_timeout;
285
286		if (get_user(new_timeout, p))
287			return -EFAULT;
288
289		/* arbitrary upper limit */
290		if (new_timeout < 1 || new_timeout > 3600)
291			return -EINVAL;
292
293		timeout = new_timeout;
294		wdt_keepalive();
295		/* Fall through */
296	}
 
297	case WDIOC_GETTIMEOUT:
298		return put_user(timeout, p);
299	default:
300		return -ENOTTY;
301	}
302}
303
304static const struct file_operations wdt_fops = {
305	.owner		= THIS_MODULE,
306	.llseek		= no_llseek,
307	.write		= fop_write,
308	.open		= fop_open,
309	.release	= fop_close,
310	.unlocked_ioctl	= fop_ioctl,
 
311};
312
313static struct miscdevice wdt_miscdev = {
314	.minor	= WATCHDOG_MINOR,
315	.name	= "watchdog",
316	.fops	= &wdt_fops,
317};
318
319/*
320 *	Notifier for system down
321 */
322
323static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
324	void *unused)
325{
326	if (code == SYS_DOWN || code == SYS_HALT)
327		wdt_turnoff();
328	return NOTIFY_DONE;
329}
330
331/*
332 *	The WDT needs to learn about soft shutdowns in order to
333 *	turn the timebomb registers off.
334 */
335
336static struct notifier_block wdt_notifier = {
337	.notifier_call = wdt_notify_sys,
338};
339
340static void __exit w83877f_wdt_unload(void)
341{
342	wdt_turnoff();
343
344	/* Deregister */
345	misc_deregister(&wdt_miscdev);
346
347	unregister_reboot_notifier(&wdt_notifier);
348	release_region(WDT_PING, 1);
349	release_region(ENABLE_W83877F_PORT, 2);
350}
351
352static int __init w83877f_wdt_init(void)
353{
354	int rc = -EBUSY;
355
356	if (timeout < 1 || timeout > 3600) { /* arbitrary upper limit */
357		timeout = WATCHDOG_TIMEOUT;
358		pr_info("timeout value must be 1 <= x <= 3600, using %d\n",
359			timeout);
360	}
361
362	if (!request_region(ENABLE_W83877F_PORT, 2, "W83877F WDT")) {
363		pr_err("I/O address 0x%04x already in use\n",
364		       ENABLE_W83877F_PORT);
365		rc = -EIO;
366		goto err_out;
367	}
368
369	if (!request_region(WDT_PING, 1, "W8387FF WDT")) {
370		pr_err("I/O address 0x%04x already in use\n", WDT_PING);
371		rc = -EIO;
372		goto err_out_region1;
373	}
374
375	rc = register_reboot_notifier(&wdt_notifier);
376	if (rc) {
377		pr_err("cannot register reboot notifier (err=%d)\n", rc);
378		goto err_out_region2;
379	}
380
381	rc = misc_register(&wdt_miscdev);
382	if (rc) {
383		pr_err("cannot register miscdev on minor=%d (err=%d)\n",
384		       wdt_miscdev.minor, rc);
385		goto err_out_reboot;
386	}
387
388	pr_info("WDT driver for W83877F initialised. timeout=%d sec (nowayout=%d)\n",
389		timeout, nowayout);
390
391	return 0;
392
393err_out_reboot:
394	unregister_reboot_notifier(&wdt_notifier);
395err_out_region2:
396	release_region(WDT_PING, 1);
397err_out_region1:
398	release_region(ENABLE_W83877F_PORT, 2);
399err_out:
400	return rc;
401}
402
403module_init(w83877f_wdt_init);
404module_exit(w83877f_wdt_unload);
405
406MODULE_AUTHOR("Scott and Bill Jennings");
407MODULE_DESCRIPTION("Driver for watchdog timer in w83877f chip");
408MODULE_LICENSE("GPL");