1 /***************************************************************************
2  *   Copyright (C) 2006 by Hans Edgington <hans@edgington.nl>              *
3  *   Copyright (C) 2007-2009 Hans de Goede <hdegoede@redhat.com>           *
4  *   Copyright (C) 2010 Giel van Schijndel <me@mortis.eu>                  *
5  *                                                                         *
6  *   This program is free software; you can redistribute it and/or modify  *
7  *   it under the terms of the GNU General Public License as published by  *
8  *   the Free Software Foundation; either version 2 of the License, or     *
9  *   (at your option) any later version.                                   *
10  *                                                                         *
11  *   This program is distributed in the hope that it will be useful,       *
12  *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
13  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
14  *   GNU General Public License for more details.                          *
15  *                                                                         *
16  *   You should have received a copy of the GNU General Public License     *
17  *   along with this program; if not, write to the                         *
18  *   Free Software Foundation, Inc.,                                       *
19  *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
20  ***************************************************************************/
21 
22 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
23 
24 #include <linux/err.h>
25 #include <linux/fs.h>
26 #include <linux/init.h>
27 #include <linux/io.h>
28 #include <linux/ioport.h>
29 #include <linux/miscdevice.h>
30 #include <linux/module.h>
31 #include <linux/mutex.h>
32 #include <linux/notifier.h>
33 #include <linux/reboot.h>
34 #include <linux/uaccess.h>
35 #include <linux/watchdog.h>
36 
37 #define DRVNAME "f71808e_wdt"
38 
39 #define SIO_F71808FG_LD_WDT	0x07	/* Watchdog timer logical device */
40 #define SIO_UNLOCK_KEY		0x87	/* Key to enable Super-I/O */
41 #define SIO_LOCK_KEY		0xAA	/* Key to disable Super-I/O */
42 
43 #define SIO_REG_LDSEL		0x07	/* Logical device select */
44 #define SIO_REG_DEVID		0x20	/* Device ID (2 bytes) */
45 #define SIO_REG_DEVREV		0x22	/* Device revision */
46 #define SIO_REG_MANID		0x23	/* Fintek ID (2 bytes) */
47 #define SIO_REG_ROM_ADDR_SEL	0x27	/* ROM address select */
48 #define SIO_F81866_REG_PORT_SEL	0x27	/* F81866 Multi-Function Register */
49 #define SIO_REG_MFUNCT1		0x29	/* Multi function select 1 */
50 #define SIO_REG_MFUNCT2		0x2a	/* Multi function select 2 */
51 #define SIO_REG_MFUNCT3		0x2b	/* Multi function select 3 */
52 #define SIO_F81866_REG_GPIO1	0x2c	/* F81866 GPIO1 Enable Register */
53 #define SIO_REG_ENABLE		0x30	/* Logical device enable */
54 #define SIO_REG_ADDR		0x60	/* Logical device address (2 bytes) */
55 
56 #define SIO_FINTEK_ID		0x1934	/* Manufacturers ID */
57 #define SIO_F71808_ID		0x0901	/* Chipset ID */
58 #define SIO_F71858_ID		0x0507	/* Chipset ID */
59 #define SIO_F71862_ID		0x0601	/* Chipset ID */
60 #define SIO_F71869_ID		0x0814	/* Chipset ID */
61 #define SIO_F71869A_ID		0x1007	/* Chipset ID */
62 #define SIO_F71882_ID		0x0541	/* Chipset ID */
63 #define SIO_F71889_ID		0x0723	/* Chipset ID */
64 #define SIO_F81865_ID		0x0704	/* Chipset ID */
65 #define SIO_F81866_ID		0x1010	/* Chipset ID */
66 
67 #define F71808FG_REG_WDO_CONF		0xf0
68 #define F71808FG_REG_WDT_CONF		0xf5
69 #define F71808FG_REG_WD_TIME		0xf6
70 
71 #define F71808FG_FLAG_WDOUT_EN		7
72 
73 #define F71808FG_FLAG_WDTMOUT_STS	6
74 #define F71808FG_FLAG_WD_EN		5
75 #define F71808FG_FLAG_WD_PULSE		4
76 #define F71808FG_FLAG_WD_UNIT		3
77 
78 #define F81865_REG_WDO_CONF		0xfa
79 #define F81865_FLAG_WDOUT_EN		0
80 
81 /* Default values */
82 #define WATCHDOG_TIMEOUT	60	/* 1 minute default timeout */
83 #define WATCHDOG_MAX_TIMEOUT	(60 * 255)
84 #define WATCHDOG_PULSE_WIDTH	125	/* 125 ms, default pulse width for
85 					   watchdog signal */
86 #define WATCHDOG_F71862FG_PIN	63	/* default watchdog reset output
87 					   pin number 63 */
88 
89 static unsigned short force_id;
90 module_param(force_id, ushort, 0);
91 MODULE_PARM_DESC(force_id, "Override the detected device ID");
92 
93 static const int max_timeout = WATCHDOG_MAX_TIMEOUT;
94 static int timeout = WATCHDOG_TIMEOUT;	/* default timeout in seconds */
95 module_param(timeout, int, 0);
96 MODULE_PARM_DESC(timeout,
97 	"Watchdog timeout in seconds. 1<= timeout <="
98 			__MODULE_STRING(WATCHDOG_MAX_TIMEOUT) " (default="
99 			__MODULE_STRING(WATCHDOG_TIMEOUT) ")");
100 
101 static unsigned int pulse_width = WATCHDOG_PULSE_WIDTH;
102 module_param(pulse_width, uint, 0);
103 MODULE_PARM_DESC(pulse_width,
104 	"Watchdog signal pulse width. 0(=level), 1 ms, 25 ms, 125 ms or 5000 ms"
105 			" (default=" __MODULE_STRING(WATCHDOG_PULSE_WIDTH) ")");
106 
107 static unsigned int f71862fg_pin = WATCHDOG_F71862FG_PIN;
108 module_param(f71862fg_pin, uint, 0);
109 MODULE_PARM_DESC(f71862fg_pin,
110 	"Watchdog f71862fg reset output pin configuration. Choose pin 56 or 63"
111 			" (default=" __MODULE_STRING(WATCHDOG_F71862FG_PIN)")");
112 
113 static bool nowayout = WATCHDOG_NOWAYOUT;
114 module_param(nowayout, bool, 0444);
115 MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close");
116 
117 static unsigned int start_withtimeout;
118 module_param(start_withtimeout, uint, 0);
119 MODULE_PARM_DESC(start_withtimeout, "Start watchdog timer on module load with"
120 	" given initial timeout. Zero (default) disables this feature.");
121 
122 enum chips { f71808fg, f71858fg, f71862fg, f71869, f71882fg, f71889fg, f81865,
123 	     f81866};
124 
125 static const char *f71808e_names[] = {
126 	"f71808fg",
127 	"f71858fg",
128 	"f71862fg",
129 	"f71869",
130 	"f71882fg",
131 	"f71889fg",
132 	"f81865",
133 	"f81866",
134 };
135 
136 /* Super-I/O Function prototypes */
137 static inline int superio_inb(int base, int reg);
138 static inline int superio_inw(int base, int reg);
139 static inline void superio_outb(int base, int reg, u8 val);
140 static inline void superio_set_bit(int base, int reg, int bit);
141 static inline void superio_clear_bit(int base, int reg, int bit);
142 static inline int superio_enter(int base);
143 static inline void superio_select(int base, int ld);
144 static inline void superio_exit(int base);
145 
146 struct watchdog_data {
147 	unsigned short	sioaddr;
148 	enum chips	type;
149 	unsigned long	opened;
150 	struct mutex	lock;
151 	char		expect_close;
152 	struct watchdog_info ident;
153 
154 	unsigned short	timeout;
155 	u8		timer_val;	/* content for the wd_time register */
156 	char		minutes_mode;
157 	u8		pulse_val;	/* pulse width flag */
158 	char		pulse_mode;	/* enable pulse output mode? */
159 	char		caused_reboot;	/* last reboot was by the watchdog */
160 };
161 
162 static struct watchdog_data watchdog = {
163 	.lock = __MUTEX_INITIALIZER(watchdog.lock),
164 };
165 
166 /* Super I/O functions */
167 static inline int superio_inb(int base, int reg)
168 {
169 	outb(reg, base);
170 	return inb(base + 1);
171 }
172 
173 static int superio_inw(int base, int reg)
174 {
175 	int val;
176 	val  = superio_inb(base, reg) << 8;
177 	val |= superio_inb(base, reg + 1);
178 	return val;
179 }
180 
181 static inline void superio_outb(int base, int reg, u8 val)
182 {
183 	outb(reg, base);
184 	outb(val, base + 1);
185 }
186 
187 static inline void superio_set_bit(int base, int reg, int bit)
188 {
189 	unsigned long val = superio_inb(base, reg);
190 	__set_bit(bit, &val);
191 	superio_outb(base, reg, val);
192 }
193 
194 static inline void superio_clear_bit(int base, int reg, int bit)
195 {
196 	unsigned long val = superio_inb(base, reg);
197 	__clear_bit(bit, &val);
198 	superio_outb(base, reg, val);
199 }
200 
201 static inline int superio_enter(int base)
202 {
203 	/* Don't step on other drivers' I/O space by accident */
204 	if (!request_muxed_region(base, 2, DRVNAME)) {
205 		pr_err("I/O address 0x%04x already in use\n", (int)base);
206 		return -EBUSY;
207 	}
208 
209 	/* according to the datasheet the key must be sent twice! */
210 	outb(SIO_UNLOCK_KEY, base);
211 	outb(SIO_UNLOCK_KEY, base);
212 
213 	return 0;
214 }
215 
216 static inline void superio_select(int base, int ld)
217 {
218 	outb(SIO_REG_LDSEL, base);
219 	outb(ld, base + 1);
220 }
221 
222 static inline void superio_exit(int base)
223 {
224 	outb(SIO_LOCK_KEY, base);
225 	release_region(base, 2);
226 }
227 
228 static int watchdog_set_timeout(int timeout)
229 {
230 	if (timeout <= 0
231 	 || timeout >  max_timeout) {
232 		pr_err("watchdog timeout out of range\n");
233 		return -EINVAL;
234 	}
235 
236 	mutex_lock(&watchdog.lock);
237 
238 	watchdog.timeout = timeout;
239 	if (timeout > 0xff) {
240 		watchdog.timer_val = DIV_ROUND_UP(timeout, 60);
241 		watchdog.minutes_mode = true;
242 	} else {
243 		watchdog.timer_val = timeout;
244 		watchdog.minutes_mode = false;
245 	}
246 
247 	mutex_unlock(&watchdog.lock);
248 
249 	return 0;
250 }
251 
252 static int watchdog_set_pulse_width(unsigned int pw)
253 {
254 	int err = 0;
255 
256 	mutex_lock(&watchdog.lock);
257 
258 	if        (pw <=    1) {
259 		watchdog.pulse_val = 0;
260 	} else if (pw <=   25) {
261 		watchdog.pulse_val = 1;
262 	} else if (pw <=  125) {
263 		watchdog.pulse_val = 2;
264 	} else if (pw <= 5000) {
265 		watchdog.pulse_val = 3;
266 	} else {
267 		pr_err("pulse width out of range\n");
268 		err = -EINVAL;
269 		goto exit_unlock;
270 	}
271 
272 	watchdog.pulse_mode = pw;
273 
274 exit_unlock:
275 	mutex_unlock(&watchdog.lock);
276 	return err;
277 }
278 
279 static int watchdog_keepalive(void)
280 {
281 	int err = 0;
282 
283 	mutex_lock(&watchdog.lock);
284 	err = superio_enter(watchdog.sioaddr);
285 	if (err)
286 		goto exit_unlock;
287 	superio_select(watchdog.sioaddr, SIO_F71808FG_LD_WDT);
288 
289 	if (watchdog.minutes_mode)
290 		/* select minutes for timer units */
291 		superio_set_bit(watchdog.sioaddr, F71808FG_REG_WDT_CONF,
292 				F71808FG_FLAG_WD_UNIT);
293 	else
294 		/* select seconds for timer units */
295 		superio_clear_bit(watchdog.sioaddr, F71808FG_REG_WDT_CONF,
296 				F71808FG_FLAG_WD_UNIT);
297 
298 	/* Set timer value */
299 	superio_outb(watchdog.sioaddr, F71808FG_REG_WD_TIME,
300 			   watchdog.timer_val);
301 
302 	superio_exit(watchdog.sioaddr);
303 
304 exit_unlock:
305 	mutex_unlock(&watchdog.lock);
306 	return err;
307 }
308 
309 static int f71862fg_pin_configure(unsigned short ioaddr)
310 {
311 	/* When ioaddr is non-zero the calling function has to take care of
312 	   mutex handling and superio preparation! */
313 
314 	if (f71862fg_pin == 63) {
315 		if (ioaddr) {
316 			/* SPI must be disabled first to use this pin! */
317 			superio_clear_bit(ioaddr, SIO_REG_ROM_ADDR_SEL, 6);
318 			superio_set_bit(ioaddr, SIO_REG_MFUNCT3, 4);
319 		}
320 	} else if (f71862fg_pin == 56) {
321 		if (ioaddr)
322 			superio_set_bit(ioaddr, SIO_REG_MFUNCT1, 1);
323 	} else {
324 		pr_err("Invalid argument f71862fg_pin=%d\n", f71862fg_pin);
325 		return -EINVAL;
326 	}
327 	return 0;
328 }
329 
330 static int watchdog_start(void)
331 {
332 	/* Make sure we don't die as soon as the watchdog is enabled below */
333 	int err = watchdog_keepalive();
334 	if (err)
335 		return err;
336 
337 	mutex_lock(&watchdog.lock);
338 	err = superio_enter(watchdog.sioaddr);
339 	if (err)
340 		goto exit_unlock;
341 	superio_select(watchdog.sioaddr, SIO_F71808FG_LD_WDT);
342 
343 	/* Watchdog pin configuration */
344 	switch (watchdog.type) {
345 	case f71808fg:
346 		/* Set pin 21 to GPIO23/WDTRST#, then to WDTRST# */
347 		superio_clear_bit(watchdog.sioaddr, SIO_REG_MFUNCT2, 3);
348 		superio_clear_bit(watchdog.sioaddr, SIO_REG_MFUNCT3, 3);
349 		break;
350 
351 	case f71862fg:
352 		err = f71862fg_pin_configure(watchdog.sioaddr);
353 		if (err)
354 			goto exit_superio;
355 		break;
356 
357 	case f71869:
358 		/* GPIO14 --> WDTRST# */
359 		superio_clear_bit(watchdog.sioaddr, SIO_REG_MFUNCT1, 4);
360 		break;
361 
362 	case f71882fg:
363 		/* Set pin 56 to WDTRST# */
364 		superio_set_bit(watchdog.sioaddr, SIO_REG_MFUNCT1, 1);
365 		break;
366 
367 	case f71889fg:
368 		/* set pin 40 to WDTRST# */
369 		superio_outb(watchdog.sioaddr, SIO_REG_MFUNCT3,
370 			superio_inb(watchdog.sioaddr, SIO_REG_MFUNCT3) & 0xcf);
371 		break;
372 
373 	case f81865:
374 		/* Set pin 70 to WDTRST# */
375 		superio_clear_bit(watchdog.sioaddr, SIO_REG_MFUNCT3, 5);
376 		break;
377 
378 	case f81866:
379 		/* Set pin 70 to WDTRST# */
380 		superio_clear_bit(watchdog.sioaddr, SIO_F81866_REG_PORT_SEL,
381 				  BIT(3) | BIT(0));
382 		superio_set_bit(watchdog.sioaddr, SIO_F81866_REG_PORT_SEL,
383 				BIT(2));
384 		/*
385 		 * GPIO1 Control Register when 27h BIT3:2 = 01 & BIT0 = 0.
386 		 * The PIN 70(GPIO15/WDTRST) is controlled by 2Ch:
387 		 *     BIT5: 0 -> WDTRST#
388 		 *           1 -> GPIO15
389 		 */
390 		superio_clear_bit(watchdog.sioaddr, SIO_F81866_REG_GPIO1,
391 				  BIT(5));
392 		break;
393 
394 	default:
395 		/*
396 		 * 'default' label to shut up the compiler and catch
397 		 * programmer errors
398 		 */
399 		err = -ENODEV;
400 		goto exit_superio;
401 	}
402 
403 	superio_select(watchdog.sioaddr, SIO_F71808FG_LD_WDT);
404 	superio_set_bit(watchdog.sioaddr, SIO_REG_ENABLE, 0);
405 
406 	if (watchdog.type == f81865 || watchdog.type == f81866)
407 		superio_set_bit(watchdog.sioaddr, F81865_REG_WDO_CONF,
408 				F81865_FLAG_WDOUT_EN);
409 	else
410 		superio_set_bit(watchdog.sioaddr, F71808FG_REG_WDO_CONF,
411 				F71808FG_FLAG_WDOUT_EN);
412 
413 	superio_set_bit(watchdog.sioaddr, F71808FG_REG_WDT_CONF,
414 			F71808FG_FLAG_WD_EN);
415 
416 	if (watchdog.pulse_mode) {
417 		/* Select "pulse" output mode with given duration */
418 		u8 wdt_conf = superio_inb(watchdog.sioaddr,
419 				F71808FG_REG_WDT_CONF);
420 
421 		/* Set WD_PSWIDTH bits (1:0) */
422 		wdt_conf = (wdt_conf & 0xfc) | (watchdog.pulse_val & 0x03);
423 		/* Set WD_PULSE to "pulse" mode */
424 		wdt_conf |= BIT(F71808FG_FLAG_WD_PULSE);
425 
426 		superio_outb(watchdog.sioaddr, F71808FG_REG_WDT_CONF,
427 				wdt_conf);
428 	} else {
429 		/* Select "level" output mode */
430 		superio_clear_bit(watchdog.sioaddr, F71808FG_REG_WDT_CONF,
431 				F71808FG_FLAG_WD_PULSE);
432 	}
433 
434 exit_superio:
435 	superio_exit(watchdog.sioaddr);
436 exit_unlock:
437 	mutex_unlock(&watchdog.lock);
438 
439 	return err;
440 }
441 
442 static int watchdog_stop(void)
443 {
444 	int err = 0;
445 
446 	mutex_lock(&watchdog.lock);
447 	err = superio_enter(watchdog.sioaddr);
448 	if (err)
449 		goto exit_unlock;
450 	superio_select(watchdog.sioaddr, SIO_F71808FG_LD_WDT);
451 
452 	superio_clear_bit(watchdog.sioaddr, F71808FG_REG_WDT_CONF,
453 			F71808FG_FLAG_WD_EN);
454 
455 	superio_exit(watchdog.sioaddr);
456 
457 exit_unlock:
458 	mutex_unlock(&watchdog.lock);
459 
460 	return err;
461 }
462 
463 static int watchdog_get_status(void)
464 {
465 	int status = 0;
466 
467 	mutex_lock(&watchdog.lock);
468 	status = (watchdog.caused_reboot) ? WDIOF_CARDRESET : 0;
469 	mutex_unlock(&watchdog.lock);
470 
471 	return status;
472 }
473 
474 static bool watchdog_is_running(void)
475 {
476 	/*
477 	 * if we fail to determine the watchdog's status assume it to be
478 	 * running to be on the safe side
479 	 */
480 	bool is_running = true;
481 
482 	mutex_lock(&watchdog.lock);
483 	if (superio_enter(watchdog.sioaddr))
484 		goto exit_unlock;
485 	superio_select(watchdog.sioaddr, SIO_F71808FG_LD_WDT);
486 
487 	is_running = (superio_inb(watchdog.sioaddr, SIO_REG_ENABLE) & BIT(0))
488 		&& (superio_inb(watchdog.sioaddr, F71808FG_REG_WDT_CONF)
489 			& F71808FG_FLAG_WD_EN);
490 
491 	superio_exit(watchdog.sioaddr);
492 
493 exit_unlock:
494 	mutex_unlock(&watchdog.lock);
495 	return is_running;
496 }
497 
498 /* /dev/watchdog api */
499 
500 static int watchdog_open(struct inode *inode, struct file *file)
501 {
502 	int err;
503 
504 	/* If the watchdog is alive we don't need to start it again */
505 	if (test_and_set_bit(0, &watchdog.opened))
506 		return -EBUSY;
507 
508 	err = watchdog_start();
509 	if (err) {
510 		clear_bit(0, &watchdog.opened);
511 		return err;
512 	}
513 
514 	if (nowayout)
515 		__module_get(THIS_MODULE);
516 
517 	watchdog.expect_close = 0;
518 	return nonseekable_open(inode, file);
519 }
520 
521 static int watchdog_release(struct inode *inode, struct file *file)
522 {
523 	clear_bit(0, &watchdog.opened);
524 
525 	if (!watchdog.expect_close) {
526 		watchdog_keepalive();
527 		pr_crit("Unexpected close, not stopping watchdog!\n");
528 	} else if (!nowayout) {
529 		watchdog_stop();
530 	}
531 	return 0;
532 }
533 
534 /*
535  *      watchdog_write:
536  *      @file: file handle to the watchdog
537  *      @buf: buffer to write
538  *      @count: count of bytes
539  *      @ppos: pointer to the position to write. No seeks allowed
540  *
541  *      A write to a watchdog device is defined as a keepalive signal. Any
542  *      write of data will do, as we we don't define content meaning.
543  */
544 
545 static ssize_t watchdog_write(struct file *file, const char __user *buf,
546 			    size_t count, loff_t *ppos)
547 {
548 	if (count) {
549 		if (!nowayout) {
550 			size_t i;
551 
552 			/* In case it was set long ago */
553 			bool expect_close = false;
554 
555 			for (i = 0; i != count; i++) {
556 				char c;
557 				if (get_user(c, buf + i))
558 					return -EFAULT;
559 				expect_close = (c == 'V');
560 			}
561 
562 			/* Properly order writes across fork()ed processes */
563 			mutex_lock(&watchdog.lock);
564 			watchdog.expect_close = expect_close;
565 			mutex_unlock(&watchdog.lock);
566 		}
567 
568 		/* someone wrote to us, we should restart timer */
569 		watchdog_keepalive();
570 	}
571 	return count;
572 }
573 
574 /*
575  *      watchdog_ioctl:
576  *      @inode: inode of the device
577  *      @file: file handle to the device
578  *      @cmd: watchdog command
579  *      @arg: argument pointer
580  *
581  *      The watchdog API defines a common set of functions for all watchdogs
582  *      according to their available features.
583  */
584 static long watchdog_ioctl(struct file *file, unsigned int cmd,
585 	unsigned long arg)
586 {
587 	int status;
588 	int new_options;
589 	int new_timeout;
590 	union {
591 		struct watchdog_info __user *ident;
592 		int __user *i;
593 	} uarg;
594 
595 	uarg.i = (int __user *)arg;
596 
597 	switch (cmd) {
598 	case WDIOC_GETSUPPORT:
599 		return copy_to_user(uarg.ident, &watchdog.ident,
600 			sizeof(watchdog.ident)) ? -EFAULT : 0;
601 
602 	case WDIOC_GETSTATUS:
603 		status = watchdog_get_status();
604 		if (status < 0)
605 			return status;
606 		return put_user(status, uarg.i);
607 
608 	case WDIOC_GETBOOTSTATUS:
609 		return put_user(0, uarg.i);
610 
611 	case WDIOC_SETOPTIONS:
612 		if (get_user(new_options, uarg.i))
613 			return -EFAULT;
614 
615 		if (new_options & WDIOS_DISABLECARD)
616 			watchdog_stop();
617 
618 		if (new_options & WDIOS_ENABLECARD)
619 			return watchdog_start();
620 
621 
622 	case WDIOC_KEEPALIVE:
623 		watchdog_keepalive();
624 		return 0;
625 
626 	case WDIOC_SETTIMEOUT:
627 		if (get_user(new_timeout, uarg.i))
628 			return -EFAULT;
629 
630 		if (watchdog_set_timeout(new_timeout))
631 			return -EINVAL;
632 
633 		watchdog_keepalive();
634 		/* Fall */
635 
636 	case WDIOC_GETTIMEOUT:
637 		return put_user(watchdog.timeout, uarg.i);
638 
639 	default:
640 		return -ENOTTY;
641 
642 	}
643 }
644 
645 static int watchdog_notify_sys(struct notifier_block *this, unsigned long code,
646 	void *unused)
647 {
648 	if (code == SYS_DOWN || code == SYS_HALT)
649 		watchdog_stop();
650 	return NOTIFY_DONE;
651 }
652 
653 static const struct file_operations watchdog_fops = {
654 	.owner		= THIS_MODULE,
655 	.llseek		= no_llseek,
656 	.open		= watchdog_open,
657 	.release	= watchdog_release,
658 	.write		= watchdog_write,
659 	.unlocked_ioctl	= watchdog_ioctl,
660 };
661 
662 static struct miscdevice watchdog_miscdev = {
663 	.minor		= WATCHDOG_MINOR,
664 	.name		= "watchdog",
665 	.fops		= &watchdog_fops,
666 };
667 
668 static struct notifier_block watchdog_notifier = {
669 	.notifier_call = watchdog_notify_sys,
670 };
671 
672 static int __init watchdog_init(int sioaddr)
673 {
674 	int wdt_conf, err = 0;
675 
676 	/* No need to lock watchdog.lock here because no entry points
677 	 * into the module have been registered yet.
678 	 */
679 	watchdog.sioaddr = sioaddr;
680 	watchdog.ident.options = WDIOC_SETTIMEOUT
681 				| WDIOF_MAGICCLOSE
682 				| WDIOF_KEEPALIVEPING;
683 
684 	snprintf(watchdog.ident.identity,
685 		sizeof(watchdog.ident.identity), "%s watchdog",
686 		f71808e_names[watchdog.type]);
687 
688 	err = superio_enter(sioaddr);
689 	if (err)
690 		return err;
691 	superio_select(watchdog.sioaddr, SIO_F71808FG_LD_WDT);
692 
693 	wdt_conf = superio_inb(sioaddr, F71808FG_REG_WDT_CONF);
694 	watchdog.caused_reboot = wdt_conf & BIT(F71808FG_FLAG_WDTMOUT_STS);
695 
696 	superio_exit(sioaddr);
697 
698 	err = watchdog_set_timeout(timeout);
699 	if (err)
700 		return err;
701 	err = watchdog_set_pulse_width(pulse_width);
702 	if (err)
703 		return err;
704 
705 	err = register_reboot_notifier(&watchdog_notifier);
706 	if (err)
707 		return err;
708 
709 	err = misc_register(&watchdog_miscdev);
710 	if (err) {
711 		pr_err("cannot register miscdev on minor=%d\n",
712 		       watchdog_miscdev.minor);
713 		goto exit_reboot;
714 	}
715 
716 	if (start_withtimeout) {
717 		if (start_withtimeout <= 0
718 		 || start_withtimeout >  max_timeout) {
719 			pr_err("starting timeout out of range\n");
720 			err = -EINVAL;
721 			goto exit_miscdev;
722 		}
723 
724 		err = watchdog_start();
725 		if (err) {
726 			pr_err("cannot start watchdog timer\n");
727 			goto exit_miscdev;
728 		}
729 
730 		mutex_lock(&watchdog.lock);
731 		err = superio_enter(sioaddr);
732 		if (err)
733 			goto exit_unlock;
734 		superio_select(watchdog.sioaddr, SIO_F71808FG_LD_WDT);
735 
736 		if (start_withtimeout > 0xff) {
737 			/* select minutes for timer units */
738 			superio_set_bit(sioaddr, F71808FG_REG_WDT_CONF,
739 				F71808FG_FLAG_WD_UNIT);
740 			superio_outb(sioaddr, F71808FG_REG_WD_TIME,
741 				DIV_ROUND_UP(start_withtimeout, 60));
742 		} else {
743 			/* select seconds for timer units */
744 			superio_clear_bit(sioaddr, F71808FG_REG_WDT_CONF,
745 				F71808FG_FLAG_WD_UNIT);
746 			superio_outb(sioaddr, F71808FG_REG_WD_TIME,
747 				start_withtimeout);
748 		}
749 
750 		superio_exit(sioaddr);
751 		mutex_unlock(&watchdog.lock);
752 
753 		if (nowayout)
754 			__module_get(THIS_MODULE);
755 
756 		pr_info("watchdog started with initial timeout of %u sec\n",
757 			start_withtimeout);
758 	}
759 
760 	return 0;
761 
762 exit_unlock:
763 	mutex_unlock(&watchdog.lock);
764 exit_miscdev:
765 	misc_deregister(&watchdog_miscdev);
766 exit_reboot:
767 	unregister_reboot_notifier(&watchdog_notifier);
768 
769 	return err;
770 }
771 
772 static int __init f71808e_find(int sioaddr)
773 {
774 	u16 devid;
775 	int err = superio_enter(sioaddr);
776 	if (err)
777 		return err;
778 
779 	devid = superio_inw(sioaddr, SIO_REG_MANID);
780 	if (devid != SIO_FINTEK_ID) {
781 		pr_debug("Not a Fintek device\n");
782 		err = -ENODEV;
783 		goto exit;
784 	}
785 
786 	devid = force_id ? force_id : superio_inw(sioaddr, SIO_REG_DEVID);
787 	switch (devid) {
788 	case SIO_F71808_ID:
789 		watchdog.type = f71808fg;
790 		break;
791 	case SIO_F71862_ID:
792 		watchdog.type = f71862fg;
793 		err = f71862fg_pin_configure(0); /* validate module parameter */
794 		break;
795 	case SIO_F71869_ID:
796 	case SIO_F71869A_ID:
797 		watchdog.type = f71869;
798 		break;
799 	case SIO_F71882_ID:
800 		watchdog.type = f71882fg;
801 		break;
802 	case SIO_F71889_ID:
803 		watchdog.type = f71889fg;
804 		break;
805 	case SIO_F71858_ID:
806 		/* Confirmed (by datasheet) not to have a watchdog. */
807 		err = -ENODEV;
808 		goto exit;
809 	case SIO_F81865_ID:
810 		watchdog.type = f81865;
811 		break;
812 	case SIO_F81866_ID:
813 		watchdog.type = f81866;
814 		break;
815 	default:
816 		pr_info("Unrecognized Fintek device: %04x\n",
817 			(unsigned int)devid);
818 		err = -ENODEV;
819 		goto exit;
820 	}
821 
822 	pr_info("Found %s watchdog chip, revision %d\n",
823 		f71808e_names[watchdog.type],
824 		(int)superio_inb(sioaddr, SIO_REG_DEVREV));
825 exit:
826 	superio_exit(sioaddr);
827 	return err;
828 }
829 
830 static int __init f71808e_init(void)
831 {
832 	static const unsigned short addrs[] = { 0x2e, 0x4e };
833 	int err = -ENODEV;
834 	int i;
835 
836 	for (i = 0; i < ARRAY_SIZE(addrs); i++) {
837 		err = f71808e_find(addrs[i]);
838 		if (err == 0)
839 			break;
840 	}
841 	if (i == ARRAY_SIZE(addrs))
842 		return err;
843 
844 	return watchdog_init(addrs[i]);
845 }
846 
847 static void __exit f71808e_exit(void)
848 {
849 	if (watchdog_is_running()) {
850 		pr_warn("Watchdog timer still running, stopping it\n");
851 		watchdog_stop();
852 	}
853 	misc_deregister(&watchdog_miscdev);
854 	unregister_reboot_notifier(&watchdog_notifier);
855 }
856 
857 MODULE_DESCRIPTION("F71808E Watchdog Driver");
858 MODULE_AUTHOR("Giel van Schijndel <me@mortis.eu>");
859 MODULE_LICENSE("GPL");
860 
861 module_init(f71808e_init);
862 module_exit(f71808e_exit);
863