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
47static	int timeout = DEFAULT_TIMEOUT;
48static	int timeoutW;			/* timeout in watchdog counter units */
49static	unsigned long timer_alive;
50static	int testmode;
51static	char expect_close;
52static	DEFINE_SPINLOCK(spinlock);
53
54module_param(timeout, int, 0);
55MODULE_PARM_DESC(timeout,
56		"Watchdog timeout in seconds (15..7635), default="
57				__MODULE_STRING(DEFAULT_TIMEOUT) ")");
58module_param(testmode, int, 0);
59MODULE_PARM_DESC(testmode, "Watchdog testmode (1 = no reboot), default=0");
60
61static bool nowayout = WATCHDOG_NOWAYOUT;
62module_param(nowayout, bool, 0);
63MODULE_PARM_DESC(nowayout,
64		"Watchdog cannot be stopped once started (default="
65				__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
66
67/*
68 * Start the watchdog
69 */
70
71static 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
142static 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
197static 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
225static 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
257static 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
291static 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
304static 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
332static 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
372static const struct watchdog_info ident = {
373	.options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
374	.firmware_version =	1,
375	.identity = WATCHDOG_NAME,
376};
377
378static 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
441static 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
449static 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
458static struct miscdevice wdt_miscdev = {
459	.minor		= WATCHDOG_MINOR,
460	.name		= "watchdog",
461	.fops		= &wdt_fops,
462};
463
464static struct notifier_block wdt_notifier = {
465	.notifier_call = wdt_notify_sys,
466};
467
468static 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
508err_out_reboot:
509	unregister_reboot_notifier(&wdt_notifier);
510err_out_region:
511	release_region(IO_INDEX_PORT, 2);
512err_out:
513	return rc;
514}
515
516static 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
524module_init(w83977f_wdt_init);
525module_exit(w83977f_wdt_exit);
526
527MODULE_AUTHOR("Jose Goncalves <jose.goncalves@inov.pt>");
528MODULE_DESCRIPTION("Driver for watchdog timer in W83977F I/O chip");
529MODULE_LICENSE("GPL");
530