1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /***************************************************************************
3  *   Copyright (C) 2006 by Hans Edgington <hans@edgington.nl>              *
4  *   Copyright (C) 2007-2009 Hans de Goede <hdegoede@redhat.com>           *
5  *   Copyright (C) 2010 Giel van Schijndel <me@mortis.eu>                  *
6  *                                                                         *
7  ***************************************************************************/
8 
9 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
10 
11 #include <linux/err.h>
12 #include <linux/fs.h>
13 #include <linux/init.h>
14 #include <linux/io.h>
15 #include <linux/ioport.h>
16 #include <linux/miscdevice.h>
17 #include <linux/module.h>
18 #include <linux/mutex.h>
19 #include <linux/notifier.h>
20 #include <linux/reboot.h>
21 #include <linux/uaccess.h>
22 #include <linux/watchdog.h>
23 
24 #define DRVNAME "f71808e_wdt"
25 
26 #define SIO_F71808FG_LD_WDT	0x07	/* Watchdog timer logical device */
27 #define SIO_UNLOCK_KEY		0x87	/* Key to enable Super-I/O */
28 #define SIO_LOCK_KEY		0xAA	/* Key to disable Super-I/O */
29 
30 #define SIO_REG_LDSEL		0x07	/* Logical device select */
31 #define SIO_REG_DEVID		0x20	/* Device ID (2 bytes) */
32 #define SIO_REG_DEVREV		0x22	/* Device revision */
33 #define SIO_REG_MANID		0x23	/* Fintek ID (2 bytes) */
34 #define SIO_REG_ROM_ADDR_SEL	0x27	/* ROM address select */
35 #define SIO_F81866_REG_PORT_SEL	0x27	/* F81866 Multi-Function Register */
36 #define SIO_REG_MFUNCT1		0x29	/* Multi function select 1 */
37 #define SIO_REG_MFUNCT2		0x2a	/* Multi function select 2 */
38 #define SIO_REG_MFUNCT3		0x2b	/* Multi function select 3 */
39 #define SIO_F81866_REG_GPIO1	0x2c	/* F81866 GPIO1 Enable Register */
40 #define SIO_REG_ENABLE		0x30	/* Logical device enable */
41 #define SIO_REG_ADDR		0x60	/* Logical device address (2 bytes) */
42 
43 #define SIO_FINTEK_ID		0x1934	/* Manufacturers ID */
44 #define SIO_F71808_ID		0x0901	/* Chipset ID */
45 #define SIO_F71858_ID		0x0507	/* Chipset ID */
46 #define SIO_F71862_ID		0x0601	/* Chipset ID */
47 #define SIO_F71868_ID		0x1106	/* Chipset ID */
48 #define SIO_F71869_ID		0x0814	/* Chipset ID */
49 #define SIO_F71869A_ID		0x1007	/* Chipset ID */
50 #define SIO_F71882_ID		0x0541	/* Chipset ID */
51 #define SIO_F71889_ID		0x0723	/* Chipset ID */
52 #define SIO_F81865_ID		0x0704	/* Chipset ID */
53 #define SIO_F81866_ID		0x1010	/* Chipset ID */
54 
55 #define F71808FG_REG_WDO_CONF		0xf0
56 #define F71808FG_REG_WDT_CONF		0xf5
57 #define F71808FG_REG_WD_TIME		0xf6
58 
59 #define F71808FG_FLAG_WDOUT_EN		7
60 
61 #define F71808FG_FLAG_WDTMOUT_STS	6
62 #define F71808FG_FLAG_WD_EN		5
63 #define F71808FG_FLAG_WD_PULSE		4
64 #define F71808FG_FLAG_WD_UNIT		3
65 
66 #define F81865_REG_WDO_CONF		0xfa
67 #define F81865_FLAG_WDOUT_EN		0
68 
69 /* Default values */
70 #define WATCHDOG_TIMEOUT	60	/* 1 minute default timeout */
71 #define WATCHDOG_MAX_TIMEOUT	(60 * 255)
72 #define WATCHDOG_PULSE_WIDTH	125	/* 125 ms, default pulse width for
73 					   watchdog signal */
74 #define WATCHDOG_F71862FG_PIN	63	/* default watchdog reset output
75 					   pin number 63 */
76 
77 static unsigned short force_id;
78 module_param(force_id, ushort, 0);
79 MODULE_PARM_DESC(force_id, "Override the detected device ID");
80 
81 static const int max_timeout = WATCHDOG_MAX_TIMEOUT;
82 static int timeout = WATCHDOG_TIMEOUT;	/* default timeout in seconds */
83 module_param(timeout, int, 0);
84 MODULE_PARM_DESC(timeout,
85 	"Watchdog timeout in seconds. 1<= timeout <="
86 			__MODULE_STRING(WATCHDOG_MAX_TIMEOUT) " (default="
87 			__MODULE_STRING(WATCHDOG_TIMEOUT) ")");
88 
89 static unsigned int pulse_width = WATCHDOG_PULSE_WIDTH;
90 module_param(pulse_width, uint, 0);
91 MODULE_PARM_DESC(pulse_width,
92 	"Watchdog signal pulse width. 0(=level), 1, 25, 30, 125, 150, 5000 or 6000 ms"
93 			" (default=" __MODULE_STRING(WATCHDOG_PULSE_WIDTH) ")");
94 
95 static unsigned int f71862fg_pin = WATCHDOG_F71862FG_PIN;
96 module_param(f71862fg_pin, uint, 0);
97 MODULE_PARM_DESC(f71862fg_pin,
98 	"Watchdog f71862fg reset output pin configuration. Choose pin 56 or 63"
99 			" (default=" __MODULE_STRING(WATCHDOG_F71862FG_PIN)")");
100 
101 static bool nowayout = WATCHDOG_NOWAYOUT;
102 module_param(nowayout, bool, 0444);
103 MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close");
104 
105 static unsigned int start_withtimeout;
106 module_param(start_withtimeout, uint, 0);
107 MODULE_PARM_DESC(start_withtimeout, "Start watchdog timer on module load with"
108 	" given initial timeout. Zero (default) disables this feature.");
109 
110 enum chips { f71808fg, f71858fg, f71862fg, f71868, f71869, f71882fg, f71889fg,
111 	     f81865, f81866};
112 
113 static const char *f71808e_names[] = {
114 	"f71808fg",
115 	"f71858fg",
116 	"f71862fg",
117 	"f71868",
118 	"f71869",
119 	"f71882fg",
120 	"f71889fg",
121 	"f81865",
122 	"f81866",
123 };
124 
125 /* Super-I/O Function prototypes */
126 static inline int superio_inb(int base, int reg);
127 static inline int superio_inw(int base, int reg);
128 static inline void superio_outb(int base, int reg, u8 val);
129 static inline void superio_set_bit(int base, int reg, int bit);
130 static inline void superio_clear_bit(int base, int reg, int bit);
131 static inline int superio_enter(int base);
132 static inline void superio_select(int base, int ld);
133 static inline void superio_exit(int base);
134 
135 struct watchdog_data {
136 	unsigned short	sioaddr;
137 	enum chips	type;
138 	unsigned long	opened;
139 	struct mutex	lock;
140 	char		expect_close;
141 	struct watchdog_info ident;
142 
143 	unsigned short	timeout;
144 	u8		timer_val;	/* content for the wd_time register */
145 	char		minutes_mode;
146 	u8		pulse_val;	/* pulse width flag */
147 	char		pulse_mode;	/* enable pulse output mode? */
148 	char		caused_reboot;	/* last reboot was by the watchdog */
149 };
150 
151 static struct watchdog_data watchdog = {
152 	.lock = __MUTEX_INITIALIZER(watchdog.lock),
153 };
154 
155 /* Super I/O functions */
156 static inline int superio_inb(int base, int reg)
157 {
158 	outb(reg, base);
159 	return inb(base + 1);
160 }
161 
162 static int superio_inw(int base, int reg)
163 {
164 	int val;
165 	val  = superio_inb(base, reg) << 8;
166 	val |= superio_inb(base, reg + 1);
167 	return val;
168 }
169 
170 static inline void superio_outb(int base, int reg, u8 val)
171 {
172 	outb(reg, base);
173 	outb(val, base + 1);
174 }
175 
176 static inline void superio_set_bit(int base, int reg, int bit)
177 {
178 	unsigned long val = superio_inb(base, reg);
179 	__set_bit(bit, &val);
180 	superio_outb(base, reg, val);
181 }
182 
183 static inline void superio_clear_bit(int base, int reg, int bit)
184 {
185 	unsigned long val = superio_inb(base, reg);
186 	__clear_bit(bit, &val);
187 	superio_outb(base, reg, val);
188 }
189 
190 static inline int superio_enter(int base)
191 {
192 	/* Don't step on other drivers' I/O space by accident */
193 	if (!request_muxed_region(base, 2, DRVNAME)) {
194 		pr_err("I/O address 0x%04x already in use\n", (int)base);
195 		return -EBUSY;
196 	}
197 
198 	/* according to the datasheet the key must be sent twice! */
199 	outb(SIO_UNLOCK_KEY, base);
200 	outb(SIO_UNLOCK_KEY, base);
201 
202 	return 0;
203 }
204 
205 static inline void superio_select(int base, int ld)
206 {
207 	outb(SIO_REG_LDSEL, base);
208 	outb(ld, base + 1);
209 }
210 
211 static inline void superio_exit(int base)
212 {
213 	outb(SIO_LOCK_KEY, base);
214 	release_region(base, 2);
215 }
216 
217 static int watchdog_set_timeout(int timeout)
218 {
219 	if (timeout <= 0
220 	 || timeout >  max_timeout) {
221 		pr_err("watchdog timeout out of range\n");
222 		return -EINVAL;
223 	}
224 
225 	mutex_lock(&watchdog.lock);
226 
227 	watchdog.timeout = timeout;
228 	if (timeout > 0xff) {
229 		watchdog.timer_val = DIV_ROUND_UP(timeout, 60);
230 		watchdog.minutes_mode = true;
231 	} else {
232 		watchdog.timer_val = timeout;
233 		watchdog.minutes_mode = false;
234 	}
235 
236 	mutex_unlock(&watchdog.lock);
237 
238 	return 0;
239 }
240 
241 static int watchdog_set_pulse_width(unsigned int pw)
242 {
243 	int err = 0;
244 	unsigned int t1 = 25, t2 = 125, t3 = 5000;
245 
246 	if (watchdog.type == f71868) {
247 		t1 = 30;
248 		t2 = 150;
249 		t3 = 6000;
250 	}
251 
252 	mutex_lock(&watchdog.lock);
253 
254 	if        (pw <=  1) {
255 		watchdog.pulse_val = 0;
256 	} else if (pw <= t1) {
257 		watchdog.pulse_val = 1;
258 	} else if (pw <= t2) {
259 		watchdog.pulse_val = 2;
260 	} else if (pw <= t3) {
261 		watchdog.pulse_val = 3;
262 	} else {
263 		pr_err("pulse width out of range\n");
264 		err = -EINVAL;
265 		goto exit_unlock;
266 	}
267 
268 	watchdog.pulse_mode = pw;
269 
270 exit_unlock:
271 	mutex_unlock(&watchdog.lock);
272 	return err;
273 }
274 
275 static int watchdog_keepalive(void)
276 {
277 	int err = 0;
278 
279 	mutex_lock(&watchdog.lock);
280 	err = superio_enter(watchdog.sioaddr);
281 	if (err)
282 		goto exit_unlock;
283 	superio_select(watchdog.sioaddr, SIO_F71808FG_LD_WDT);
284 
285 	if (watchdog.minutes_mode)
286 		/* select minutes for timer units */
287 		superio_set_bit(watchdog.sioaddr, F71808FG_REG_WDT_CONF,
288 				F71808FG_FLAG_WD_UNIT);
289 	else
290 		/* select seconds for timer units */
291 		superio_clear_bit(watchdog.sioaddr, F71808FG_REG_WDT_CONF,
292 				F71808FG_FLAG_WD_UNIT);
293 
294 	/* Set timer value */
295 	superio_outb(watchdog.sioaddr, F71808FG_REG_WD_TIME,
296 			   watchdog.timer_val);
297 
298 	superio_exit(watchdog.sioaddr);
299 
300 exit_unlock:
301 	mutex_unlock(&watchdog.lock);
302 	return err;
303 }
304 
305 static int f71862fg_pin_configure(unsigned short ioaddr)
306 {
307 	/* When ioaddr is non-zero the calling function has to take care of
308 	   mutex handling and superio preparation! */
309 
310 	if (f71862fg_pin == 63) {
311 		if (ioaddr) {
312 			/* SPI must be disabled first to use this pin! */
313 			superio_clear_bit(ioaddr, SIO_REG_ROM_ADDR_SEL, 6);
314 			superio_set_bit(ioaddr, SIO_REG_MFUNCT3, 4);
315 		}
316 	} else if (f71862fg_pin == 56) {
317 		if (ioaddr)
318 			superio_set_bit(ioaddr, SIO_REG_MFUNCT1, 1);
319 	} else {
320 		pr_err("Invalid argument f71862fg_pin=%d\n", f71862fg_pin);
321 		return -EINVAL;
322 	}
323 	return 0;
324 }
325 
326 static int watchdog_start(void)
327 {
328 	int err;
329 	u8 tmp;
330 
331 	/* Make sure we don't die as soon as the watchdog is enabled below */
332 	err = watchdog_keepalive();
333 	if (err)
334 		return err;
335 
336 	mutex_lock(&watchdog.lock);
337 	err = superio_enter(watchdog.sioaddr);
338 	if (err)
339 		goto exit_unlock;
340 	superio_select(watchdog.sioaddr, SIO_F71808FG_LD_WDT);
341 
342 	/* Watchdog pin configuration */
343 	switch (watchdog.type) {
344 	case f71808fg:
345 		/* Set pin 21 to GPIO23/WDTRST#, then to WDTRST# */
346 		superio_clear_bit(watchdog.sioaddr, SIO_REG_MFUNCT2, 3);
347 		superio_clear_bit(watchdog.sioaddr, SIO_REG_MFUNCT3, 3);
348 		break;
349 
350 	case f71862fg:
351 		err = f71862fg_pin_configure(watchdog.sioaddr);
352 		if (err)
353 			goto exit_superio;
354 		break;
355 
356 	case f71868:
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 		/*
380 		 * GPIO1 Control Register when 27h BIT3:2 = 01 & BIT0 = 0.
381 		 * The PIN 70(GPIO15/WDTRST) is controlled by 2Ch:
382 		 *     BIT5: 0 -> WDTRST#
383 		 *           1 -> GPIO15
384 		 */
385 		tmp = superio_inb(watchdog.sioaddr, SIO_F81866_REG_PORT_SEL);
386 		tmp &= ~(BIT(3) | BIT(0));
387 		tmp |= BIT(2);
388 		superio_outb(watchdog.sioaddr, SIO_F81866_REG_PORT_SEL, tmp);
389 
390 		superio_clear_bit(watchdog.sioaddr, SIO_F81866_REG_GPIO1, 5);
391 		break;
392 
393 	default:
394 		/*
395 		 * 'default' label to shut up the compiler and catch
396 		 * programmer errors
397 		 */
398 		err = -ENODEV;
399 		goto exit_superio;
400 	}
401 
402 	superio_select(watchdog.sioaddr, SIO_F71808FG_LD_WDT);
403 	superio_set_bit(watchdog.sioaddr, SIO_REG_ENABLE, 0);
404 
405 	if (watchdog.type == f81865 || watchdog.type == f81866)
406 		superio_set_bit(watchdog.sioaddr, F81865_REG_WDO_CONF,
407 				F81865_FLAG_WDOUT_EN);
408 	else
409 		superio_set_bit(watchdog.sioaddr, F71808FG_REG_WDO_CONF,
410 				F71808FG_FLAG_WDOUT_EN);
411 
412 	superio_set_bit(watchdog.sioaddr, F71808FG_REG_WDT_CONF,
413 			F71808FG_FLAG_WD_EN);
414 
415 	if (watchdog.pulse_mode) {
416 		/* Select "pulse" output mode with given duration */
417 		u8 wdt_conf = superio_inb(watchdog.sioaddr,
418 				F71808FG_REG_WDT_CONF);
419 
420 		/* Set WD_PSWIDTH bits (1:0) */
421 		wdt_conf = (wdt_conf & 0xfc) | (watchdog.pulse_val & 0x03);
422 		/* Set WD_PULSE to "pulse" mode */
423 		wdt_conf |= BIT(F71808FG_FLAG_WD_PULSE);
424 
425 		superio_outb(watchdog.sioaddr, F71808FG_REG_WDT_CONF,
426 				wdt_conf);
427 	} else {
428 		/* Select "level" output mode */
429 		superio_clear_bit(watchdog.sioaddr, F71808FG_REG_WDT_CONF,
430 				F71808FG_FLAG_WD_PULSE);
431 	}
432 
433 exit_superio:
434 	superio_exit(watchdog.sioaddr);
435 exit_unlock:
436 	mutex_unlock(&watchdog.lock);
437 
438 	return err;
439 }
440 
441 static int watchdog_stop(void)
442 {
443 	int err = 0;
444 
445 	mutex_lock(&watchdog.lock);
446 	err = superio_enter(watchdog.sioaddr);
447 	if (err)
448 		goto exit_unlock;
449 	superio_select(watchdog.sioaddr, SIO_F71808FG_LD_WDT);
450 
451 	superio_clear_bit(watchdog.sioaddr, F71808FG_REG_WDT_CONF,
452 			F71808FG_FLAG_WD_EN);
453 
454 	superio_exit(watchdog.sioaddr);
455 
456 exit_unlock:
457 	mutex_unlock(&watchdog.lock);
458 
459 	return err;
460 }
461 
462 static int watchdog_get_status(void)
463 {
464 	int status = 0;
465 
466 	mutex_lock(&watchdog.lock);
467 	status = (watchdog.caused_reboot) ? WDIOF_CARDRESET : 0;
468 	mutex_unlock(&watchdog.lock);
469 
470 	return status;
471 }
472 
473 static bool watchdog_is_running(void)
474 {
475 	/*
476 	 * if we fail to determine the watchdog's status assume it to be
477 	 * running to be on the safe side
478 	 */
479 	bool is_running = true;
480 
481 	mutex_lock(&watchdog.lock);
482 	if (superio_enter(watchdog.sioaddr))
483 		goto exit_unlock;
484 	superio_select(watchdog.sioaddr, SIO_F71808FG_LD_WDT);
485 
486 	is_running = (superio_inb(watchdog.sioaddr, SIO_REG_ENABLE) & BIT(0))
487 		&& (superio_inb(watchdog.sioaddr, F71808FG_REG_WDT_CONF)
488 			& BIT(F71808FG_FLAG_WD_EN));
489 
490 	superio_exit(watchdog.sioaddr);
491 
492 exit_unlock:
493 	mutex_unlock(&watchdog.lock);
494 	return is_running;
495 }
496 
497 /* /dev/watchdog api */
498 
499 static int watchdog_open(struct inode *inode, struct file *file)
500 {
501 	int err;
502 
503 	/* If the watchdog is alive we don't need to start it again */
504 	if (test_and_set_bit(0, &watchdog.opened))
505 		return -EBUSY;
506 
507 	err = watchdog_start();
508 	if (err) {
509 		clear_bit(0, &watchdog.opened);
510 		return err;
511 	}
512 
513 	if (nowayout)
514 		__module_get(THIS_MODULE);
515 
516 	watchdog.expect_close = 0;
517 	return stream_open(inode, file);
518 }
519 
520 static int watchdog_release(struct inode *inode, struct file *file)
521 {
522 	clear_bit(0, &watchdog.opened);
523 
524 	if (!watchdog.expect_close) {
525 		watchdog_keepalive();
526 		pr_crit("Unexpected close, not stopping watchdog!\n");
527 	} else if (!nowayout) {
528 		watchdog_stop();
529 	}
530 	return 0;
531 }
532 
533 /*
534  *      watchdog_write:
535  *      @file: file handle to the watchdog
536  *      @buf: buffer to write
537  *      @count: count of bytes
538  *      @ppos: pointer to the position to write. No seeks allowed
539  *
540  *      A write to a watchdog device is defined as a keepalive signal. Any
541  *      write of data will do, as we we don't define content meaning.
542  */
543 
544 static ssize_t watchdog_write(struct file *file, const char __user *buf,
545 			    size_t count, loff_t *ppos)
546 {
547 	if (count) {
548 		if (!nowayout) {
549 			size_t i;
550 
551 			/* In case it was set long ago */
552 			bool expect_close = false;
553 
554 			for (i = 0; i != count; i++) {
555 				char c;
556 				if (get_user(c, buf + i))
557 					return -EFAULT;
558 				if (c == 'V')
559 					expect_close = true;
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 		/* fall through */
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 through */
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_F71868_ID:
796 		watchdog.type = f71868;
797 		break;
798 	case SIO_F71869_ID:
799 	case SIO_F71869A_ID:
800 		watchdog.type = f71869;
801 		break;
802 	case SIO_F71882_ID:
803 		watchdog.type = f71882fg;
804 		break;
805 	case SIO_F71889_ID:
806 		watchdog.type = f71889fg;
807 		break;
808 	case SIO_F71858_ID:
809 		/* Confirmed (by datasheet) not to have a watchdog. */
810 		err = -ENODEV;
811 		goto exit;
812 	case SIO_F81865_ID:
813 		watchdog.type = f81865;
814 		break;
815 	case SIO_F81866_ID:
816 		watchdog.type = f81866;
817 		break;
818 	default:
819 		pr_info("Unrecognized Fintek device: %04x\n",
820 			(unsigned int)devid);
821 		err = -ENODEV;
822 		goto exit;
823 	}
824 
825 	pr_info("Found %s watchdog chip, revision %d\n",
826 		f71808e_names[watchdog.type],
827 		(int)superio_inb(sioaddr, SIO_REG_DEVREV));
828 exit:
829 	superio_exit(sioaddr);
830 	return err;
831 }
832 
833 static int __init f71808e_init(void)
834 {
835 	static const unsigned short addrs[] = { 0x2e, 0x4e };
836 	int err = -ENODEV;
837 	int i;
838 
839 	for (i = 0; i < ARRAY_SIZE(addrs); i++) {
840 		err = f71808e_find(addrs[i]);
841 		if (err == 0)
842 			break;
843 	}
844 	if (i == ARRAY_SIZE(addrs))
845 		return err;
846 
847 	return watchdog_init(addrs[i]);
848 }
849 
850 static void __exit f71808e_exit(void)
851 {
852 	if (watchdog_is_running()) {
853 		pr_warn("Watchdog timer still running, stopping it\n");
854 		watchdog_stop();
855 	}
856 	misc_deregister(&watchdog_miscdev);
857 	unregister_reboot_notifier(&watchdog_notifier);
858 }
859 
860 MODULE_DESCRIPTION("F71808E Watchdog Driver");
861 MODULE_AUTHOR("Giel van Schijndel <me@mortis.eu>");
862 MODULE_LICENSE("GPL");
863 
864 module_init(f71808e_init);
865 module_exit(f71808e_exit);
866