1 /*
2  *	W83977F Watchdog Timer Driver for Winbond W83977F I/O Chip
3  *
4  *	(c) Copyright 2005  Jose Goncalves <jose.goncalves@inov.pt>
5  *
6  *      Based on w83877f_wdt.c by Scott Jennings,
7  *           and wdt977.c by Woody Suwalski
8  *
9  *			-----------------------
10  *
11  *	This program is free software; you can redistribute it and/or
12  *	modify it under the terms of the GNU General Public License
13  *	as published by the Free Software Foundation; either version
14  *	2 of the License, or (at your option) any later version.
15  *
16  */
17 
18 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
19 
20 #include <linux/module.h>
21 #include <linux/moduleparam.h>
22 #include <linux/types.h>
23 #include <linux/kernel.h>
24 #include <linux/fs.h>
25 #include <linux/miscdevice.h>
26 #include <linux/init.h>
27 #include <linux/ioport.h>
28 #include <linux/watchdog.h>
29 #include <linux/notifier.h>
30 #include <linux/reboot.h>
31 #include <linux/uaccess.h>
32 #include <linux/io.h>
33 
34 
35 #define WATCHDOG_VERSION  "1.00"
36 #define WATCHDOG_NAME     "W83977F WDT"
37 
38 #define IO_INDEX_PORT     0x3F0
39 #define IO_DATA_PORT      (IO_INDEX_PORT+1)
40 
41 #define UNLOCK_DATA       0x87
42 #define LOCK_DATA         0xAA
43 #define DEVICE_REGISTER   0x07
44 
45 #define	DEFAULT_TIMEOUT   45		/* default timeout in seconds */
46 
47 static	int timeout = DEFAULT_TIMEOUT;
48 static	int timeoutW;			/* timeout in watchdog counter units */
49 static	unsigned long timer_alive;
50 static	int testmode;
51 static	char expect_close;
52 static	DEFINE_SPINLOCK(spinlock);
53 
54 module_param(timeout, int, 0);
55 MODULE_PARM_DESC(timeout,
56 		"Watchdog timeout in seconds (15..7635), default="
57 				__MODULE_STRING(DEFAULT_TIMEOUT) ")");
58 module_param(testmode, int, 0);
59 MODULE_PARM_DESC(testmode, "Watchdog testmode (1 = no reboot), default=0");
60 
61 static bool nowayout = WATCHDOG_NOWAYOUT;
62 module_param(nowayout, bool, 0);
63 MODULE_PARM_DESC(nowayout,
64 		"Watchdog cannot be stopped once started (default="
65 				__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
66 
67 /*
68  * Start the watchdog
69  */
70 
71 static int wdt_start(void)
72 {
73 	unsigned long flags;
74 
75 	spin_lock_irqsave(&spinlock, flags);
76 
77 	/* Unlock the SuperIO chip */
78 	outb_p(UNLOCK_DATA, IO_INDEX_PORT);
79 	outb_p(UNLOCK_DATA, IO_INDEX_PORT);
80 
81 	/*
82 	 * Select device Aux2 (device=8) to set watchdog regs F2, F3 and F4.
83 	 * F2 has the timeout in watchdog counter units.
84 	 * F3 is set to enable watchdog LED blink at timeout.
85 	 * F4 is used to just clear the TIMEOUT'ed state (bit 0).
86 	 */
87 	outb_p(DEVICE_REGISTER, IO_INDEX_PORT);
88 	outb_p(0x08, IO_DATA_PORT);
89 	outb_p(0xF2, IO_INDEX_PORT);
90 	outb_p(timeoutW, IO_DATA_PORT);
91 	outb_p(0xF3, IO_INDEX_PORT);
92 	outb_p(0x08, IO_DATA_PORT);
93 	outb_p(0xF4, IO_INDEX_PORT);
94 	outb_p(0x00, IO_DATA_PORT);
95 
96 	/* Set device Aux2 active */
97 	outb_p(0x30, IO_INDEX_PORT);
98 	outb_p(0x01, IO_DATA_PORT);
99 
100 	/*
101 	 * Select device Aux1 (dev=7) to set GP16 as the watchdog output
102 	 * (in reg E6) and GP13 as the watchdog LED output (in reg E3).
103 	 * Map GP16 at pin 119.
104 	 * In test mode watch the bit 0 on F4 to indicate "triggered" or
105 	 * check watchdog LED on SBC.
106 	 */
107 	outb_p(DEVICE_REGISTER, IO_INDEX_PORT);
108 	outb_p(0x07, IO_DATA_PORT);
109 	if (!testmode) {
110 		unsigned pin_map;
111 
112 		outb_p(0xE6, IO_INDEX_PORT);
113 		outb_p(0x0A, IO_DATA_PORT);
114 		outb_p(0x2C, IO_INDEX_PORT);
115 		pin_map = inb_p(IO_DATA_PORT);
116 		pin_map |= 0x10;
117 		pin_map &= ~(0x20);
118 		outb_p(0x2C, IO_INDEX_PORT);
119 		outb_p(pin_map, IO_DATA_PORT);
120 	}
121 	outb_p(0xE3, IO_INDEX_PORT);
122 	outb_p(0x08, IO_DATA_PORT);
123 
124 	/* Set device Aux1 active */
125 	outb_p(0x30, IO_INDEX_PORT);
126 	outb_p(0x01, IO_DATA_PORT);
127 
128 	/* Lock the SuperIO chip */
129 	outb_p(LOCK_DATA, IO_INDEX_PORT);
130 
131 	spin_unlock_irqrestore(&spinlock, flags);
132 
133 	pr_info("activated\n");
134 
135 	return 0;
136 }
137 
138 /*
139  * Stop the watchdog
140  */
141 
142 static int wdt_stop(void)
143 {
144 	unsigned long flags;
145 
146 	spin_lock_irqsave(&spinlock, flags);
147 
148 	/* Unlock the SuperIO chip */
149 	outb_p(UNLOCK_DATA, IO_INDEX_PORT);
150 	outb_p(UNLOCK_DATA, IO_INDEX_PORT);
151 
152 	/*
153 	 * Select device Aux2 (device=8) to set watchdog regs F2, F3 and F4.
154 	 * F2 is reset to its default value (watchdog timer disabled).
155 	 * F3 is reset to its default state.
156 	 * F4 clears the TIMEOUT'ed state (bit 0) - back to default.
157 	 */
158 	outb_p(DEVICE_REGISTER, IO_INDEX_PORT);
159 	outb_p(0x08, IO_DATA_PORT);
160 	outb_p(0xF2, IO_INDEX_PORT);
161 	outb_p(0xFF, IO_DATA_PORT);
162 	outb_p(0xF3, IO_INDEX_PORT);
163 	outb_p(0x00, IO_DATA_PORT);
164 	outb_p(0xF4, IO_INDEX_PORT);
165 	outb_p(0x00, IO_DATA_PORT);
166 	outb_p(0xF2, IO_INDEX_PORT);
167 	outb_p(0x00, IO_DATA_PORT);
168 
169 	/*
170 	 * Select device Aux1 (dev=7) to set GP16 (in reg E6) and
171 	 * Gp13 (in reg E3) as inputs.
172 	 */
173 	outb_p(DEVICE_REGISTER, IO_INDEX_PORT);
174 	outb_p(0x07, IO_DATA_PORT);
175 	if (!testmode) {
176 		outb_p(0xE6, IO_INDEX_PORT);
177 		outb_p(0x01, IO_DATA_PORT);
178 	}
179 	outb_p(0xE3, IO_INDEX_PORT);
180 	outb_p(0x01, IO_DATA_PORT);
181 
182 	/* Lock the SuperIO chip */
183 	outb_p(LOCK_DATA, IO_INDEX_PORT);
184 
185 	spin_unlock_irqrestore(&spinlock, flags);
186 
187 	pr_info("shutdown\n");
188 
189 	return 0;
190 }
191 
192 /*
193  * Send a keepalive ping to the watchdog
194  * This is done by simply re-writing the timeout to reg. 0xF2
195  */
196 
197 static int wdt_keepalive(void)
198 {
199 	unsigned long flags;
200 
201 	spin_lock_irqsave(&spinlock, flags);
202 
203 	/* Unlock the SuperIO chip */
204 	outb_p(UNLOCK_DATA, IO_INDEX_PORT);
205 	outb_p(UNLOCK_DATA, IO_INDEX_PORT);
206 
207 	/* Select device Aux2 (device=8) to kick watchdog reg F2 */
208 	outb_p(DEVICE_REGISTER, IO_INDEX_PORT);
209 	outb_p(0x08, IO_DATA_PORT);
210 	outb_p(0xF2, IO_INDEX_PORT);
211 	outb_p(timeoutW, IO_DATA_PORT);
212 
213 	/* Lock the SuperIO chip */
214 	outb_p(LOCK_DATA, IO_INDEX_PORT);
215 
216 	spin_unlock_irqrestore(&spinlock, flags);
217 
218 	return 0;
219 }
220 
221 /*
222  * Set the watchdog timeout value
223  */
224 
225 static int wdt_set_timeout(int t)
226 {
227 	int tmrval;
228 
229 	/*
230 	 * Convert seconds to watchdog counter time units, rounding up.
231 	 * On PCM-5335 watchdog units are 30 seconds/step with 15 sec startup
232 	 * value. This information is supplied in the PCM-5335 manual and was
233 	 * checked by me on a real board. This is a bit strange because W83977f
234 	 * datasheet says counter unit is in minutes!
235 	 */
236 	if (t < 15)
237 		return -EINVAL;
238 
239 	tmrval = ((t + 15) + 29) / 30;
240 
241 	if (tmrval > 255)
242 		return -EINVAL;
243 
244 	/*
245 	 * timeout is the timeout in seconds,
246 	 * timeoutW is the timeout in watchdog counter units.
247 	 */
248 	timeoutW = tmrval;
249 	timeout = (timeoutW * 30) - 15;
250 	return 0;
251 }
252 
253 /*
254  * Get the watchdog status
255  */
256 
257 static int wdt_get_status(int *status)
258 {
259 	int new_status;
260 	unsigned long flags;
261 
262 	spin_lock_irqsave(&spinlock, flags);
263 
264 	/* Unlock the SuperIO chip */
265 	outb_p(UNLOCK_DATA, IO_INDEX_PORT);
266 	outb_p(UNLOCK_DATA, IO_INDEX_PORT);
267 
268 	/* Select device Aux2 (device=8) to read watchdog reg F4 */
269 	outb_p(DEVICE_REGISTER, IO_INDEX_PORT);
270 	outb_p(0x08, IO_DATA_PORT);
271 	outb_p(0xF4, IO_INDEX_PORT);
272 	new_status = inb_p(IO_DATA_PORT);
273 
274 	/* Lock the SuperIO chip */
275 	outb_p(LOCK_DATA, IO_INDEX_PORT);
276 
277 	spin_unlock_irqrestore(&spinlock, flags);
278 
279 	*status = 0;
280 	if (new_status & 1)
281 		*status |= WDIOF_CARDRESET;
282 
283 	return 0;
284 }
285 
286 
287 /*
288  *	/dev/watchdog handling
289  */
290 
291 static int wdt_open(struct inode *inode, struct file *file)
292 {
293 	/* If the watchdog is alive we don't need to start it again */
294 	if (test_and_set_bit(0, &timer_alive))
295 		return -EBUSY;
296 
297 	if (nowayout)
298 		__module_get(THIS_MODULE);
299 
300 	wdt_start();
301 	return nonseekable_open(inode, file);
302 }
303 
304 static int wdt_release(struct inode *inode, struct file *file)
305 {
306 	/*
307 	 * Shut off the timer.
308 	 * Lock it in if it's a module and we set nowayout
309 	 */
310 	if (expect_close == 42) {
311 		wdt_stop();
312 		clear_bit(0, &timer_alive);
313 	} else {
314 		wdt_keepalive();
315 		pr_crit("unexpected close, not stopping watchdog!\n");
316 	}
317 	expect_close = 0;
318 	return 0;
319 }
320 
321 /*
322  *      wdt_write:
323  *      @file: file handle to the watchdog
324  *      @buf: buffer to write (unused as data does not matter here
325  *      @count: count of bytes
326  *      @ppos: pointer to the position to write. No seeks allowed
327  *
328  *      A write to a watchdog device is defined as a keepalive signal. Any
329  *      write of data will do, as we we don't define content meaning.
330  */
331 
332 static ssize_t wdt_write(struct file *file, const char __user *buf,
333 			    size_t count, loff_t *ppos)
334 {
335 	/* See if we got the magic character 'V' and reload the timer */
336 	if (count) {
337 		if (!nowayout) {
338 			size_t ofs;
339 
340 			/* note: just in case someone wrote the
341 			   magic character long ago */
342 			expect_close = 0;
343 
344 			/* scan to see whether or not we got the
345 			   magic character */
346 			for (ofs = 0; ofs != count; ofs++) {
347 				char c;
348 				if (get_user(c, buf + ofs))
349 					return -EFAULT;
350 				if (c == 'V')
351 					expect_close = 42;
352 			}
353 		}
354 
355 		/* someone wrote to us, we should restart timer */
356 		wdt_keepalive();
357 	}
358 	return count;
359 }
360 
361 /*
362  *      wdt_ioctl:
363  *      @inode: inode of the device
364  *      @file: file handle to the device
365  *      @cmd: watchdog command
366  *      @arg: argument pointer
367  *
368  *      The watchdog API defines a common set of functions for all watchdogs
369  *      according to their available features.
370  */
371 
372 static const struct watchdog_info ident = {
373 	.options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
374 	.firmware_version =	1,
375 	.identity = WATCHDOG_NAME,
376 };
377 
378 static long wdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
379 {
380 	int status;
381 	int new_options, retval = -EINVAL;
382 	int new_timeout;
383 	union {
384 		struct watchdog_info __user *ident;
385 		int __user *i;
386 	} uarg;
387 
388 	uarg.i = (int __user *)arg;
389 
390 	switch (cmd) {
391 	case WDIOC_GETSUPPORT:
392 		return copy_to_user(uarg.ident, &ident,
393 						sizeof(ident)) ? -EFAULT : 0;
394 
395 	case WDIOC_GETSTATUS:
396 		wdt_get_status(&status);
397 		return put_user(status, uarg.i);
398 
399 	case WDIOC_GETBOOTSTATUS:
400 		return put_user(0, uarg.i);
401 
402 	case WDIOC_SETOPTIONS:
403 		if (get_user(new_options, uarg.i))
404 			return -EFAULT;
405 
406 		if (new_options & WDIOS_DISABLECARD) {
407 			wdt_stop();
408 			retval = 0;
409 		}
410 
411 		if (new_options & WDIOS_ENABLECARD) {
412 			wdt_start();
413 			retval = 0;
414 		}
415 
416 		return retval;
417 
418 	case WDIOC_KEEPALIVE:
419 		wdt_keepalive();
420 		return 0;
421 
422 	case WDIOC_SETTIMEOUT:
423 		if (get_user(new_timeout, uarg.i))
424 			return -EFAULT;
425 
426 		if (wdt_set_timeout(new_timeout))
427 			return -EINVAL;
428 
429 		wdt_keepalive();
430 		/* Fall */
431 
432 	case WDIOC_GETTIMEOUT:
433 		return put_user(timeout, uarg.i);
434 
435 	default:
436 		return -ENOTTY;
437 
438 	}
439 }
440 
441 static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
442 	void *unused)
443 {
444 	if (code == SYS_DOWN || code == SYS_HALT)
445 		wdt_stop();
446 	return NOTIFY_DONE;
447 }
448 
449 static const struct file_operations wdt_fops = {
450 	.owner		= THIS_MODULE,
451 	.llseek		= no_llseek,
452 	.write		= wdt_write,
453 	.unlocked_ioctl	= wdt_ioctl,
454 	.open		= wdt_open,
455 	.release	= wdt_release,
456 };
457 
458 static struct miscdevice wdt_miscdev = {
459 	.minor		= WATCHDOG_MINOR,
460 	.name		= "watchdog",
461 	.fops		= &wdt_fops,
462 };
463 
464 static struct notifier_block wdt_notifier = {
465 	.notifier_call = wdt_notify_sys,
466 };
467 
468 static int __init w83977f_wdt_init(void)
469 {
470 	int rc;
471 
472 	pr_info("driver v%s\n", WATCHDOG_VERSION);
473 
474 	/*
475 	 * Check that the timeout value is within it's range;
476 	 * if not reset to the default
477 	 */
478 	if (wdt_set_timeout(timeout)) {
479 		wdt_set_timeout(DEFAULT_TIMEOUT);
480 		pr_info("timeout value must be 15 <= timeout <= 7635, using %d\n",
481 			DEFAULT_TIMEOUT);
482 	}
483 
484 	if (!request_region(IO_INDEX_PORT, 2, WATCHDOG_NAME)) {
485 		pr_err("I/O address 0x%04x already in use\n", IO_INDEX_PORT);
486 		rc = -EIO;
487 		goto err_out;
488 	}
489 
490 	rc = register_reboot_notifier(&wdt_notifier);
491 	if (rc) {
492 		pr_err("cannot register reboot notifier (err=%d)\n", rc);
493 		goto err_out_region;
494 	}
495 
496 	rc = misc_register(&wdt_miscdev);
497 	if (rc) {
498 		pr_err("cannot register miscdev on minor=%d (err=%d)\n",
499 		       wdt_miscdev.minor, rc);
500 		goto err_out_reboot;
501 	}
502 
503 	pr_info("initialized. timeout=%d sec (nowayout=%d testmode=%d)\n",
504 		timeout, nowayout, testmode);
505 
506 	return 0;
507 
508 err_out_reboot:
509 	unregister_reboot_notifier(&wdt_notifier);
510 err_out_region:
511 	release_region(IO_INDEX_PORT, 2);
512 err_out:
513 	return rc;
514 }
515 
516 static void __exit w83977f_wdt_exit(void)
517 {
518 	wdt_stop();
519 	misc_deregister(&wdt_miscdev);
520 	unregister_reboot_notifier(&wdt_notifier);
521 	release_region(IO_INDEX_PORT, 2);
522 }
523 
524 module_init(w83977f_wdt_init);
525 module_exit(w83977f_wdt_exit);
526 
527 MODULE_AUTHOR("Jose Goncalves <jose.goncalves@inov.pt>");
528 MODULE_DESCRIPTION("Driver for watchdog timer in W83977F I/O chip");
529 MODULE_LICENSE("GPL");
530