xref: /openbmc/linux/drivers/watchdog/it87_wdt.c (revision 93d90ad7)
1 /*
2  *	Watchdog Timer Driver
3  *	   for ITE IT87xx Environment Control - Low Pin Count Input / Output
4  *
5  *	(c) Copyright 2007  Oliver Schuster <olivers137@aol.com>
6  *
7  *	Based on softdog.c	by Alan Cox,
8  *		 83977f_wdt.c	by Jose Goncalves,
9  *		 it87.c		by Chris Gauthron, Jean Delvare
10  *
11  *	Data-sheets: Publicly available at the ITE website
12  *		    http://www.ite.com.tw/
13  *
14  *	Support of the watchdog timers, which are available on
15  *	IT8702, IT8712, IT8716, IT8718, IT8720, IT8721, IT8726
16  *	and IT8728.
17  *
18  *	This program is free software; you can redistribute it and/or
19  *	modify it under the terms of the GNU General Public License
20  *	as published by the Free Software Foundation; either version
21  *	2 of the License, or (at your option) any later version.
22  *
23  *	This program is distributed in the hope that it will be useful,
24  *	but WITHOUT ANY WARRANTY; without even the implied warranty of
25  *	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
26  *	GNU General Public License for more details.
27  *
28  *	You should have received a copy of the GNU General Public License
29  *	along with this program; if not, write to the Free Software
30  *	Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
31  */
32 
33 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
34 
35 #include <linux/module.h>
36 #include <linux/moduleparam.h>
37 #include <linux/types.h>
38 #include <linux/kernel.h>
39 #include <linux/fs.h>
40 #include <linux/miscdevice.h>
41 #include <linux/init.h>
42 #include <linux/ioport.h>
43 #include <linux/watchdog.h>
44 #include <linux/notifier.h>
45 #include <linux/reboot.h>
46 #include <linux/uaccess.h>
47 #include <linux/io.h>
48 
49 
50 #define WATCHDOG_VERSION	"1.14"
51 #define WATCHDOG_NAME		"IT87 WDT"
52 #define DRIVER_VERSION		WATCHDOG_NAME " driver, v" WATCHDOG_VERSION "\n"
53 #define WD_MAGIC		'V'
54 
55 /* Defaults for Module Parameter */
56 #define DEFAULT_NOGAMEPORT	0
57 #define DEFAULT_NOCIR		0
58 #define DEFAULT_EXCLUSIVE	1
59 #define DEFAULT_TIMEOUT		60
60 #define DEFAULT_TESTMODE	0
61 #define DEFAULT_NOWAYOUT	WATCHDOG_NOWAYOUT
62 
63 /* IO Ports */
64 #define REG		0x2e
65 #define VAL		0x2f
66 
67 /* Logical device Numbers LDN */
68 #define GPIO		0x07
69 #define GAMEPORT	0x09
70 #define CIR		0x0a
71 
72 /* Configuration Registers and Functions */
73 #define LDNREG		0x07
74 #define CHIPID		0x20
75 #define CHIPREV		0x22
76 #define ACTREG		0x30
77 #define BASEREG		0x60
78 
79 /* Chip Id numbers */
80 #define NO_DEV_ID	0xffff
81 #define IT8702_ID	0x8702
82 #define IT8705_ID	0x8705
83 #define IT8712_ID	0x8712
84 #define IT8716_ID	0x8716
85 #define IT8718_ID	0x8718
86 #define IT8720_ID	0x8720
87 #define IT8721_ID	0x8721
88 #define IT8726_ID	0x8726	/* the data sheet suggest wrongly 0x8716 */
89 #define IT8728_ID	0x8728
90 
91 /* GPIO Configuration Registers LDN=0x07 */
92 #define WDTCTRL		0x71
93 #define WDTCFG		0x72
94 #define WDTVALLSB	0x73
95 #define WDTVALMSB	0x74
96 
97 /* GPIO Bits WDTCTRL */
98 #define WDT_CIRINT	0x80
99 #define WDT_MOUSEINT	0x40
100 #define WDT_KYBINT	0x20
101 #define WDT_GAMEPORT	0x10 /* not in it8718, it8720, it8721, it8728 */
102 #define WDT_FORCE	0x02
103 #define WDT_ZERO	0x01
104 
105 /* GPIO Bits WDTCFG */
106 #define WDT_TOV1	0x80
107 #define WDT_KRST	0x40
108 #define WDT_TOVE	0x20
109 #define WDT_PWROK	0x10 /* not in it8721 */
110 #define WDT_INT_MASK	0x0f
111 
112 /* CIR Configuration Register LDN=0x0a */
113 #define CIR_ILS		0x70
114 
115 /* The default Base address is not always available, we use this */
116 #define CIR_BASE	0x0208
117 
118 /* CIR Controller */
119 #define CIR_DR(b)	(b)
120 #define CIR_IER(b)	(b + 1)
121 #define CIR_RCR(b)	(b + 2)
122 #define CIR_TCR1(b)	(b + 3)
123 #define CIR_TCR2(b)	(b + 4)
124 #define CIR_TSR(b)	(b + 5)
125 #define CIR_RSR(b)	(b + 6)
126 #define CIR_BDLR(b)	(b + 5)
127 #define CIR_BDHR(b)	(b + 6)
128 #define CIR_IIR(b)	(b + 7)
129 
130 /* Default Base address of Game port */
131 #define GP_BASE_DEFAULT	0x0201
132 
133 /* wdt_status */
134 #define WDTS_TIMER_RUN	0
135 #define WDTS_DEV_OPEN	1
136 #define WDTS_KEEPALIVE	2
137 #define WDTS_LOCKED	3
138 #define WDTS_USE_GP	4
139 #define WDTS_EXPECTED	5
140 #define WDTS_USE_CIR	6
141 
142 static	unsigned int base, gpact, ciract, max_units, chip_type;
143 static	unsigned long wdt_status;
144 
145 static	int nogameport = DEFAULT_NOGAMEPORT;
146 static int nocir      = DEFAULT_NOCIR;
147 static	int exclusive  = DEFAULT_EXCLUSIVE;
148 static	int timeout    = DEFAULT_TIMEOUT;
149 static	int testmode   = DEFAULT_TESTMODE;
150 static	bool nowayout   = DEFAULT_NOWAYOUT;
151 
152 module_param(nogameport, int, 0);
153 MODULE_PARM_DESC(nogameport, "Forbid the activation of game port, default="
154 		__MODULE_STRING(DEFAULT_NOGAMEPORT));
155 module_param(nocir, int, 0);
156 MODULE_PARM_DESC(nocir, "Forbid the use of Consumer IR interrupts to reset timer, default="
157 		__MODULE_STRING(DEFAULT_NOCIR));
158 module_param(exclusive, int, 0);
159 MODULE_PARM_DESC(exclusive, "Watchdog exclusive device open, default="
160 		__MODULE_STRING(DEFAULT_EXCLUSIVE));
161 module_param(timeout, int, 0);
162 MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds, default="
163 		__MODULE_STRING(DEFAULT_TIMEOUT));
164 module_param(testmode, int, 0);
165 MODULE_PARM_DESC(testmode, "Watchdog test mode (1 = no reboot), default="
166 		__MODULE_STRING(DEFAULT_TESTMODE));
167 module_param(nowayout, bool, 0);
168 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started, default="
169 		__MODULE_STRING(WATCHDOG_NOWAYOUT));
170 
171 /* Superio Chip */
172 
173 static inline int superio_enter(void)
174 {
175 	/*
176 	 * Try to reserve REG and REG + 1 for exclusive access.
177 	 */
178 	if (!request_muxed_region(REG, 2, WATCHDOG_NAME))
179 		return -EBUSY;
180 
181 	outb(0x87, REG);
182 	outb(0x01, REG);
183 	outb(0x55, REG);
184 	outb(0x55, REG);
185 	return 0;
186 }
187 
188 static inline void superio_exit(void)
189 {
190 	outb(0x02, REG);
191 	outb(0x02, VAL);
192 	release_region(REG, 2);
193 }
194 
195 static inline void superio_select(int ldn)
196 {
197 	outb(LDNREG, REG);
198 	outb(ldn, VAL);
199 }
200 
201 static inline int superio_inb(int reg)
202 {
203 	outb(reg, REG);
204 	return inb(VAL);
205 }
206 
207 static inline void superio_outb(int val, int reg)
208 {
209 	outb(reg, REG);
210 	outb(val, VAL);
211 }
212 
213 static inline int superio_inw(int reg)
214 {
215 	int val;
216 	outb(reg++, REG);
217 	val = inb(VAL) << 8;
218 	outb(reg, REG);
219 	val |= inb(VAL);
220 	return val;
221 }
222 
223 static inline void superio_outw(int val, int reg)
224 {
225 	outb(reg++, REG);
226 	outb(val >> 8, VAL);
227 	outb(reg, REG);
228 	outb(val, VAL);
229 }
230 
231 /* Internal function, should be called after superio_select(GPIO) */
232 static void wdt_update_timeout(void)
233 {
234 	unsigned char cfg = WDT_KRST;
235 	int tm = timeout;
236 
237 	if (testmode)
238 		cfg = 0;
239 
240 	if (tm <= max_units)
241 		cfg |= WDT_TOV1;
242 	else
243 		tm /= 60;
244 
245 	if (chip_type != IT8721_ID)
246 		cfg |= WDT_PWROK;
247 
248 	superio_outb(cfg, WDTCFG);
249 	superio_outb(tm, WDTVALLSB);
250 	if (max_units > 255)
251 		superio_outb(tm>>8, WDTVALMSB);
252 }
253 
254 static int wdt_round_time(int t)
255 {
256 	t += 59;
257 	t -= t % 60;
258 	return t;
259 }
260 
261 /* watchdog timer handling */
262 
263 static void wdt_keepalive(void)
264 {
265 	if (test_bit(WDTS_USE_GP, &wdt_status))
266 		inb(base);
267 	else if (test_bit(WDTS_USE_CIR, &wdt_status))
268 		/* The timer reloads with around 5 msec delay */
269 		outb(0x55, CIR_DR(base));
270 	else {
271 		if (superio_enter())
272 			return;
273 
274 		superio_select(GPIO);
275 		wdt_update_timeout();
276 		superio_exit();
277 	}
278 	set_bit(WDTS_KEEPALIVE, &wdt_status);
279 }
280 
281 static int wdt_start(void)
282 {
283 	int ret = superio_enter();
284 	if (ret)
285 		return ret;
286 
287 	superio_select(GPIO);
288 	if (test_bit(WDTS_USE_GP, &wdt_status))
289 		superio_outb(WDT_GAMEPORT, WDTCTRL);
290 	else if (test_bit(WDTS_USE_CIR, &wdt_status))
291 		superio_outb(WDT_CIRINT, WDTCTRL);
292 	wdt_update_timeout();
293 
294 	superio_exit();
295 
296 	return 0;
297 }
298 
299 static int wdt_stop(void)
300 {
301 	int ret = superio_enter();
302 	if (ret)
303 		return ret;
304 
305 	superio_select(GPIO);
306 	superio_outb(0x00, WDTCTRL);
307 	superio_outb(WDT_TOV1, WDTCFG);
308 	superio_outb(0x00, WDTVALLSB);
309 	if (max_units > 255)
310 		superio_outb(0x00, WDTVALMSB);
311 
312 	superio_exit();
313 	return 0;
314 }
315 
316 /**
317  *	wdt_set_timeout - set a new timeout value with watchdog ioctl
318  *	@t: timeout value in seconds
319  *
320  *	The hardware device has a 8 or 16 bit watchdog timer (depends on
321  *	chip version) that can be configured to count seconds or minutes.
322  *
323  *	Used within WDIOC_SETTIMEOUT watchdog device ioctl.
324  */
325 
326 static int wdt_set_timeout(int t)
327 {
328 	if (t < 1 || t > max_units * 60)
329 		return -EINVAL;
330 
331 	if (t > max_units)
332 		timeout = wdt_round_time(t);
333 	else
334 		timeout = t;
335 
336 	if (test_bit(WDTS_TIMER_RUN, &wdt_status)) {
337 		int ret = superio_enter();
338 		if (ret)
339 			return ret;
340 
341 		superio_select(GPIO);
342 		wdt_update_timeout();
343 		superio_exit();
344 	}
345 	return 0;
346 }
347 
348 /**
349  *	wdt_get_status - determines the status supported by watchdog ioctl
350  *	@status: status returned to user space
351  *
352  *	The status bit of the device does not allow to distinguish
353  *	between a regular system reset and a watchdog forced reset.
354  *	But, in test mode it is useful, so it is supported through
355  *	WDIOC_GETSTATUS watchdog ioctl. Additionally the driver
356  *	reports the keepalive signal and the acception of the magic.
357  *
358  *	Used within WDIOC_GETSTATUS watchdog device ioctl.
359  */
360 
361 static int wdt_get_status(int *status)
362 {
363 	*status = 0;
364 	if (testmode) {
365 		int ret = superio_enter();
366 		if (ret)
367 			return ret;
368 
369 		superio_select(GPIO);
370 		if (superio_inb(WDTCTRL) & WDT_ZERO) {
371 			superio_outb(0x00, WDTCTRL);
372 			clear_bit(WDTS_TIMER_RUN, &wdt_status);
373 			*status |= WDIOF_CARDRESET;
374 		}
375 
376 		superio_exit();
377 	}
378 	if (test_and_clear_bit(WDTS_KEEPALIVE, &wdt_status))
379 		*status |= WDIOF_KEEPALIVEPING;
380 	if (test_bit(WDTS_EXPECTED, &wdt_status))
381 		*status |= WDIOF_MAGICCLOSE;
382 	return 0;
383 }
384 
385 /* /dev/watchdog handling */
386 
387 /**
388  *	wdt_open - watchdog file_operations .open
389  *	@inode: inode of the device
390  *	@file: file handle to the device
391  *
392  *	The watchdog timer starts by opening the device.
393  *
394  *	Used within the file operation of the watchdog device.
395  */
396 
397 static int wdt_open(struct inode *inode, struct file *file)
398 {
399 	if (exclusive && test_and_set_bit(WDTS_DEV_OPEN, &wdt_status))
400 		return -EBUSY;
401 	if (!test_and_set_bit(WDTS_TIMER_RUN, &wdt_status)) {
402 		int ret;
403 		if (nowayout && !test_and_set_bit(WDTS_LOCKED, &wdt_status))
404 			__module_get(THIS_MODULE);
405 
406 		ret = wdt_start();
407 		if (ret) {
408 			clear_bit(WDTS_LOCKED, &wdt_status);
409 			clear_bit(WDTS_TIMER_RUN, &wdt_status);
410 			clear_bit(WDTS_DEV_OPEN, &wdt_status);
411 			return ret;
412 		}
413 	}
414 	return nonseekable_open(inode, file);
415 }
416 
417 /**
418  *	wdt_release - watchdog file_operations .release
419  *	@inode: inode of the device
420  *	@file: file handle to the device
421  *
422  *	Closing the watchdog device either stops the watchdog timer
423  *	or in the case, that nowayout is set or the magic character
424  *	wasn't written, a critical warning about an running watchdog
425  *	timer is given.
426  *
427  *	Used within the file operation of the watchdog device.
428  */
429 
430 static int wdt_release(struct inode *inode, struct file *file)
431 {
432 	if (test_bit(WDTS_TIMER_RUN, &wdt_status)) {
433 		if (test_and_clear_bit(WDTS_EXPECTED, &wdt_status)) {
434 			int ret = wdt_stop();
435 			if (ret) {
436 				/*
437 				 * Stop failed. Just keep the watchdog alive
438 				 * and hope nothing bad happens.
439 				 */
440 				set_bit(WDTS_EXPECTED, &wdt_status);
441 				wdt_keepalive();
442 				return ret;
443 			}
444 			clear_bit(WDTS_TIMER_RUN, &wdt_status);
445 		} else {
446 			wdt_keepalive();
447 			pr_crit("unexpected close, not stopping watchdog!\n");
448 		}
449 	}
450 	clear_bit(WDTS_DEV_OPEN, &wdt_status);
451 	return 0;
452 }
453 
454 /**
455  *	wdt_write - watchdog file_operations .write
456  *	@file: file handle to the watchdog
457  *	@buf: buffer to write
458  *	@count: count of bytes
459  *	@ppos: pointer to the position to write. No seeks allowed
460  *
461  *	A write to a watchdog device is defined as a keepalive signal. Any
462  *	write of data will do, as we don't define content meaning.
463  *
464  *	Used within the file operation of the watchdog device.
465  */
466 
467 static ssize_t wdt_write(struct file *file, const char __user *buf,
468 			    size_t count, loff_t *ppos)
469 {
470 	if (count) {
471 		clear_bit(WDTS_EXPECTED, &wdt_status);
472 		wdt_keepalive();
473 	}
474 	if (!nowayout) {
475 		size_t ofs;
476 
477 	/* note: just in case someone wrote the magic character long ago */
478 		for (ofs = 0; ofs != count; ofs++) {
479 			char c;
480 			if (get_user(c, buf + ofs))
481 				return -EFAULT;
482 			if (c == WD_MAGIC)
483 				set_bit(WDTS_EXPECTED, &wdt_status);
484 		}
485 	}
486 	return count;
487 }
488 
489 static const struct watchdog_info ident = {
490 	.options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
491 	.firmware_version =	1,
492 	.identity = WATCHDOG_NAME,
493 };
494 
495 /**
496  *	wdt_ioctl - watchdog file_operations .unlocked_ioctl
497  *	@file: file handle to the device
498  *	@cmd: watchdog command
499  *	@arg: argument pointer
500  *
501  *	The watchdog API defines a common set of functions for all watchdogs
502  *	according to their available features.
503  *
504  *	Used within the file operation of the watchdog device.
505  */
506 
507 static long wdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
508 {
509 	int rc = 0, status, new_options, new_timeout;
510 	union {
511 		struct watchdog_info __user *ident;
512 		int __user *i;
513 	} uarg;
514 
515 	uarg.i = (int __user *)arg;
516 
517 	switch (cmd) {
518 	case WDIOC_GETSUPPORT:
519 		return copy_to_user(uarg.ident,
520 				    &ident, sizeof(ident)) ? -EFAULT : 0;
521 
522 	case WDIOC_GETSTATUS:
523 		rc = wdt_get_status(&status);
524 		if (rc)
525 			return rc;
526 		return put_user(status, uarg.i);
527 
528 	case WDIOC_GETBOOTSTATUS:
529 		return put_user(0, uarg.i);
530 
531 	case WDIOC_KEEPALIVE:
532 		wdt_keepalive();
533 		return 0;
534 
535 	case WDIOC_SETOPTIONS:
536 		if (get_user(new_options, uarg.i))
537 			return -EFAULT;
538 
539 		switch (new_options) {
540 		case WDIOS_DISABLECARD:
541 			if (test_bit(WDTS_TIMER_RUN, &wdt_status)) {
542 				rc = wdt_stop();
543 				if (rc)
544 					return rc;
545 			}
546 			clear_bit(WDTS_TIMER_RUN, &wdt_status);
547 			return 0;
548 
549 		case WDIOS_ENABLECARD:
550 			if (!test_and_set_bit(WDTS_TIMER_RUN, &wdt_status)) {
551 				rc = wdt_start();
552 				if (rc) {
553 					clear_bit(WDTS_TIMER_RUN, &wdt_status);
554 					return rc;
555 				}
556 			}
557 			return 0;
558 
559 		default:
560 			return -EFAULT;
561 		}
562 
563 	case WDIOC_SETTIMEOUT:
564 		if (get_user(new_timeout, uarg.i))
565 			return -EFAULT;
566 		rc = wdt_set_timeout(new_timeout);
567 	case WDIOC_GETTIMEOUT:
568 		if (put_user(timeout, uarg.i))
569 			return -EFAULT;
570 		return rc;
571 
572 	default:
573 		return -ENOTTY;
574 	}
575 }
576 
577 static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
578 	void *unused)
579 {
580 	if (code == SYS_DOWN || code == SYS_HALT)
581 		wdt_stop();
582 	return NOTIFY_DONE;
583 }
584 
585 static const struct file_operations wdt_fops = {
586 	.owner		= THIS_MODULE,
587 	.llseek		= no_llseek,
588 	.write		= wdt_write,
589 	.unlocked_ioctl	= wdt_ioctl,
590 	.open		= wdt_open,
591 	.release	= wdt_release,
592 };
593 
594 static struct miscdevice wdt_miscdev = {
595 	.minor		= WATCHDOG_MINOR,
596 	.name		= "watchdog",
597 	.fops		= &wdt_fops,
598 };
599 
600 static struct notifier_block wdt_notifier = {
601 	.notifier_call = wdt_notify_sys,
602 };
603 
604 static int __init it87_wdt_init(void)
605 {
606 	int rc = 0;
607 	int try_gameport = !nogameport;
608 	u8  chip_rev;
609 	int gp_rreq_fail = 0;
610 
611 	wdt_status = 0;
612 
613 	rc = superio_enter();
614 	if (rc)
615 		return rc;
616 
617 	chip_type = superio_inw(CHIPID);
618 	chip_rev  = superio_inb(CHIPREV) & 0x0f;
619 	superio_exit();
620 
621 	switch (chip_type) {
622 	case IT8702_ID:
623 		max_units = 255;
624 		break;
625 	case IT8712_ID:
626 		max_units = (chip_rev < 8) ? 255 : 65535;
627 		break;
628 	case IT8716_ID:
629 	case IT8726_ID:
630 		max_units = 65535;
631 		break;
632 	case IT8718_ID:
633 	case IT8720_ID:
634 	case IT8721_ID:
635 	case IT8728_ID:
636 		max_units = 65535;
637 		try_gameport = 0;
638 		break;
639 	case IT8705_ID:
640 		pr_err("Unsupported Chip found, Chip %04x Revision %02x\n",
641 		       chip_type, chip_rev);
642 		return -ENODEV;
643 	case NO_DEV_ID:
644 		pr_err("no device\n");
645 		return -ENODEV;
646 	default:
647 		pr_err("Unknown Chip found, Chip %04x Revision %04x\n",
648 		       chip_type, chip_rev);
649 		return -ENODEV;
650 	}
651 
652 	rc = superio_enter();
653 	if (rc)
654 		return rc;
655 
656 	superio_select(GPIO);
657 	superio_outb(WDT_TOV1, WDTCFG);
658 	superio_outb(0x00, WDTCTRL);
659 
660 	/* First try to get Gameport support */
661 	if (try_gameport) {
662 		superio_select(GAMEPORT);
663 		base = superio_inw(BASEREG);
664 		if (!base) {
665 			base = GP_BASE_DEFAULT;
666 			superio_outw(base, BASEREG);
667 		}
668 		gpact = superio_inb(ACTREG);
669 		superio_outb(0x01, ACTREG);
670 		if (request_region(base, 1, WATCHDOG_NAME))
671 			set_bit(WDTS_USE_GP, &wdt_status);
672 		else
673 			gp_rreq_fail = 1;
674 	}
675 
676 	/* If we haven't Gameport support, try to get CIR support */
677 	if (!nocir && !test_bit(WDTS_USE_GP, &wdt_status)) {
678 		if (!request_region(CIR_BASE, 8, WATCHDOG_NAME)) {
679 			if (gp_rreq_fail)
680 				pr_err("I/O Address 0x%04x and 0x%04x already in use\n",
681 				       base, CIR_BASE);
682 			else
683 				pr_err("I/O Address 0x%04x already in use\n",
684 				       CIR_BASE);
685 			rc = -EIO;
686 			goto err_out;
687 		}
688 		base = CIR_BASE;
689 
690 		superio_select(CIR);
691 		superio_outw(base, BASEREG);
692 		superio_outb(0x00, CIR_ILS);
693 		ciract = superio_inb(ACTREG);
694 		superio_outb(0x01, ACTREG);
695 		if (gp_rreq_fail) {
696 			superio_select(GAMEPORT);
697 			superio_outb(gpact, ACTREG);
698 		}
699 		set_bit(WDTS_USE_CIR, &wdt_status);
700 	}
701 
702 	if (timeout < 1 || timeout > max_units * 60) {
703 		timeout = DEFAULT_TIMEOUT;
704 		pr_warn("Timeout value out of range, use default %d sec\n",
705 			DEFAULT_TIMEOUT);
706 	}
707 
708 	if (timeout > max_units)
709 		timeout = wdt_round_time(timeout);
710 
711 	rc = register_reboot_notifier(&wdt_notifier);
712 	if (rc) {
713 		pr_err("Cannot register reboot notifier (err=%d)\n", rc);
714 		goto err_out_region;
715 	}
716 
717 	rc = misc_register(&wdt_miscdev);
718 	if (rc) {
719 		pr_err("Cannot register miscdev on minor=%d (err=%d)\n",
720 		       wdt_miscdev.minor, rc);
721 		goto err_out_reboot;
722 	}
723 
724 	/* Initialize CIR to use it as keepalive source */
725 	if (test_bit(WDTS_USE_CIR, &wdt_status)) {
726 		outb(0x00, CIR_RCR(base));
727 		outb(0xc0, CIR_TCR1(base));
728 		outb(0x5c, CIR_TCR2(base));
729 		outb(0x10, CIR_IER(base));
730 		outb(0x00, CIR_BDHR(base));
731 		outb(0x01, CIR_BDLR(base));
732 		outb(0x09, CIR_IER(base));
733 	}
734 
735 	pr_info("Chip IT%04x revision %d initialized. timeout=%d sec (nowayout=%d testmode=%d exclusive=%d nogameport=%d nocir=%d)\n",
736 		chip_type, chip_rev, timeout,
737 		nowayout, testmode, exclusive, nogameport, nocir);
738 
739 	superio_exit();
740 	return 0;
741 
742 err_out_reboot:
743 	unregister_reboot_notifier(&wdt_notifier);
744 err_out_region:
745 	if (test_bit(WDTS_USE_GP, &wdt_status))
746 		release_region(base, 1);
747 	else if (test_bit(WDTS_USE_CIR, &wdt_status)) {
748 		release_region(base, 8);
749 		superio_select(CIR);
750 		superio_outb(ciract, ACTREG);
751 	}
752 err_out:
753 	if (try_gameport) {
754 		superio_select(GAMEPORT);
755 		superio_outb(gpact, ACTREG);
756 	}
757 
758 	superio_exit();
759 	return rc;
760 }
761 
762 static void __exit it87_wdt_exit(void)
763 {
764 	if (superio_enter() == 0) {
765 		superio_select(GPIO);
766 		superio_outb(0x00, WDTCTRL);
767 		superio_outb(0x00, WDTCFG);
768 		superio_outb(0x00, WDTVALLSB);
769 		if (max_units > 255)
770 			superio_outb(0x00, WDTVALMSB);
771 		if (test_bit(WDTS_USE_GP, &wdt_status)) {
772 			superio_select(GAMEPORT);
773 			superio_outb(gpact, ACTREG);
774 		} else if (test_bit(WDTS_USE_CIR, &wdt_status)) {
775 			superio_select(CIR);
776 			superio_outb(ciract, ACTREG);
777 		}
778 		superio_exit();
779 	}
780 
781 	misc_deregister(&wdt_miscdev);
782 	unregister_reboot_notifier(&wdt_notifier);
783 
784 	if (test_bit(WDTS_USE_GP, &wdt_status))
785 		release_region(base, 1);
786 	else if (test_bit(WDTS_USE_CIR, &wdt_status))
787 		release_region(base, 8);
788 }
789 
790 module_init(it87_wdt_init);
791 module_exit(it87_wdt_exit);
792 
793 MODULE_AUTHOR("Oliver Schuster");
794 MODULE_DESCRIPTION("Hardware Watchdog Device Driver for IT87xx EC-LPC I/O");
795 MODULE_LICENSE("GPL");
796