1/*
2 *	w83627hf/thf WDT driver
3 *
4 *	(c) Copyright 2007 Vlad Drukker <vlad@storewiz.com>
5 *		added support for W83627THF.
6 *
7 *	(c) Copyright 2003,2007 Pádraig Brady <P@draigBrady.com>
8 *
9 *	Based on advantechwdt.c which is based on wdt.c.
10 *	Original copyright messages:
11 *
12 *	(c) Copyright 2000-2001 Marek Michalkiewicz <marekm@linux.org.pl>
13 *
14 *	(c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>,
15 *						All Rights Reserved.
16 *
17 *	This program is free software; you can redistribute it and/or
18 *	modify it under the terms of the GNU General Public License
19 *	as published by the Free Software Foundation; either version
20 *	2 of the License, or (at your option) any later version.
21 *
22 *	Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
23 *	warranty for any of this software. This material is provided
24 *	"AS-IS" and at no charge.
25 *
26 *	(c) Copyright 1995    Alan Cox <alan@lxorguk.ukuu.org.uk>
27 */
28
29#include <linux/module.h>
30#include <linux/moduleparam.h>
31#include <linux/types.h>
32#include <linux/miscdevice.h>
33#include <linux/watchdog.h>
34#include <linux/fs.h>
35#include <linux/ioport.h>
36#include <linux/notifier.h>
37#include <linux/reboot.h>
38#include <linux/init.h>
39#include <linux/spinlock.h>
40#include <linux/io.h>
41#include <linux/uaccess.h>
42
43#include <asm/system.h>
44
45#define WATCHDOG_NAME "w83627hf/thf/hg/dhg WDT"
46#define PFX WATCHDOG_NAME ": "
47#define WATCHDOG_TIMEOUT 60		/* 60 sec default timeout */
48
49static unsigned long wdt_is_open;
50static char expect_close;
51static DEFINE_SPINLOCK(io_lock);
52
53/* You must set this - there is no sane way to probe for this board. */
54static int wdt_io = 0x2E;
55module_param(wdt_io, int, 0);
56MODULE_PARM_DESC(wdt_io, "w83627hf/thf WDT io port (default 0x2E)");
57
58static int timeout = WATCHDOG_TIMEOUT;	/* in seconds */
59module_param(timeout, int, 0);
60MODULE_PARM_DESC(timeout,
61		"Watchdog timeout in seconds. 1 <= timeout <= 255, default="
62				__MODULE_STRING(WATCHDOG_TIMEOUT) ".");
63
64static int nowayout = WATCHDOG_NOWAYOUT;
65module_param(nowayout, int, 0);
66MODULE_PARM_DESC(nowayout,
67		"Watchdog cannot be stopped once started (default="
68				__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
69
70/*
71 *	Kernel methods.
72 */
73
74#define WDT_EFER (wdt_io+0)   /* Extended Function Enable Registers */
75#define WDT_EFIR (wdt_io+0)   /* Extended Function Index Register
76							(same as EFER) */
77#define WDT_EFDR (WDT_EFIR+1) /* Extended Function Data Register */
78
79static void w83627hf_select_wd_register(void)
80{
81	unsigned char c;
82	outb_p(0x87, WDT_EFER); /* Enter extended function mode */
83	outb_p(0x87, WDT_EFER); /* Again according to manual */
84
85	outb(0x20, WDT_EFER);	/* check chip version	*/
86	c = inb(WDT_EFDR);
87	if (c == 0x82) {	/* W83627THF		*/
88		outb_p(0x2b, WDT_EFER); /* select GPIO3 */
89		c = ((inb_p(WDT_EFDR) & 0xf7) | 0x04); /* select WDT0 */
90		outb_p(0x2b, WDT_EFER);
91		outb_p(c, WDT_EFDR);	/* set GPIO3 to WDT0 */
92	} else if (c == 0x88 || c == 0xa0) {	/* W83627EHF / W83627DHG */
93		outb_p(0x2d, WDT_EFER); /* select GPIO5 */
94		c = inb_p(WDT_EFDR) & ~0x01; /* PIN77 -> WDT0# */
95		outb_p(0x2d, WDT_EFER);
96		outb_p(c, WDT_EFDR); /* set GPIO5 to WDT0 */
97	}
98
99	outb_p(0x07, WDT_EFER); /* point to logical device number reg */
100	outb_p(0x08, WDT_EFDR); /* select logical device 8 (GPIO2) */
101	outb_p(0x30, WDT_EFER); /* select CR30 */
102	outb_p(0x01, WDT_EFDR); /* set bit 0 to activate GPIO2 */
103}
104
105static void w83627hf_unselect_wd_register(void)
106{
107	outb_p(0xAA, WDT_EFER); /* Leave extended function mode */
108}
109
110/* tyan motherboards seem to set F5 to 0x4C ?
111 * So explicitly init to appropriate value. */
112
113static void w83627hf_init(void)
114{
115	unsigned char t;
116
117	w83627hf_select_wd_register();
118
119	outb_p(0xF6, WDT_EFER); /* Select CRF6 */
120	t = inb_p(WDT_EFDR);      /* read CRF6 */
121	if (t != 0) {
122		printk(KERN_INFO PFX
123		     "Watchdog already running. Resetting timeout to %d sec\n",
124								timeout);
125		outb_p(timeout, WDT_EFDR);    /* Write back to CRF6 */
126	}
127
128	outb_p(0xF5, WDT_EFER); /* Select CRF5 */
129	t = inb_p(WDT_EFDR);      /* read CRF5 */
130	t &= ~0x0C;               /* set second mode & disable keyboard
131				    turning off watchdog */
132	t |= 0x02;		  /* enable the WDTO# output low pulse
133				    to the KBRST# pin (PIN60) */
134	outb_p(t, WDT_EFDR);    /* Write back to CRF5 */
135
136	outb_p(0xF7, WDT_EFER); /* Select CRF7 */
137	t = inb_p(WDT_EFDR);      /* read CRF7 */
138	t &= ~0xC0;               /* disable keyboard & mouse turning off
139				    watchdog */
140	outb_p(t, WDT_EFDR);    /* Write back to CRF7 */
141
142	w83627hf_unselect_wd_register();
143}
144
145static void wdt_set_time(int timeout)
146{
147	spin_lock(&io_lock);
148
149	w83627hf_select_wd_register();
150
151	outb_p(0xF6, WDT_EFER);    /* Select CRF6 */
152	outb_p(timeout, WDT_EFDR); /* Write Timeout counter to CRF6 */
153
154	w83627hf_unselect_wd_register();
155
156	spin_unlock(&io_lock);
157}
158
159static int wdt_ping(void)
160{
161	wdt_set_time(timeout);
162	return 0;
163}
164
165static int wdt_disable(void)
166{
167	wdt_set_time(0);
168	return 0;
169}
170
171static int wdt_set_heartbeat(int t)
172{
173	if (t < 1 || t > 255)
174		return -EINVAL;
175	timeout = t;
176	return 0;
177}
178
179static int wdt_get_time(void)
180{
181	int timeleft;
182
183	spin_lock(&io_lock);
184
185	w83627hf_select_wd_register();
186
187	outb_p(0xF6, WDT_EFER);    /* Select CRF6 */
188	timeleft = inb_p(WDT_EFDR); /* Read Timeout counter to CRF6 */
189
190	w83627hf_unselect_wd_register();
191
192	spin_unlock(&io_lock);
193
194	return timeleft;
195}
196
197static ssize_t wdt_write(struct file *file, const char __user *buf,
198						size_t count, loff_t *ppos)
199{
200	if (count) {
201		if (!nowayout) {
202			size_t i;
203
204			expect_close = 0;
205
206			for (i = 0; i != count; i++) {
207				char c;
208				if (get_user(c, buf + i))
209					return -EFAULT;
210				if (c == 'V')
211					expect_close = 42;
212			}
213		}
214		wdt_ping();
215	}
216	return count;
217}
218
219static long wdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
220{
221	void __user *argp = (void __user *)arg;
222	int __user *p = argp;
223	int timeval;
224	static const struct watchdog_info ident = {
225		.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT |
226							WDIOF_MAGICCLOSE,
227		.firmware_version = 1,
228		.identity = "W83627HF WDT",
229	};
230
231	switch (cmd) {
232	case WDIOC_GETSUPPORT:
233		if (copy_to_user(argp, &ident, sizeof(ident)))
234			return -EFAULT;
235		break;
236	case WDIOC_GETSTATUS:
237	case WDIOC_GETBOOTSTATUS:
238		return put_user(0, p);
239	case WDIOC_SETOPTIONS:
240	{
241		int options, retval = -EINVAL;
242
243		if (get_user(options, p))
244			return -EFAULT;
245		if (options & WDIOS_DISABLECARD) {
246			wdt_disable();
247			retval = 0;
248		}
249		if (options & WDIOS_ENABLECARD) {
250			wdt_ping();
251			retval = 0;
252		}
253		return retval;
254	}
255	case WDIOC_KEEPALIVE:
256		wdt_ping();
257		break;
258	case WDIOC_SETTIMEOUT:
259		if (get_user(timeval, p))
260			return -EFAULT;
261		if (wdt_set_heartbeat(timeval))
262			return -EINVAL;
263		wdt_ping();
264		/* Fall */
265	case WDIOC_GETTIMEOUT:
266		return put_user(timeout, p);
267	case WDIOC_GETTIMELEFT:
268		timeval = wdt_get_time();
269		return put_user(timeval, p);
270	default:
271		return -ENOTTY;
272	}
273	return 0;
274}
275
276static int wdt_open(struct inode *inode, struct file *file)
277{
278	if (test_and_set_bit(0, &wdt_is_open))
279		return -EBUSY;
280	/*
281	 *	Activate
282	 */
283
284	wdt_ping();
285	return nonseekable_open(inode, file);
286}
287
288static int wdt_close(struct inode *inode, struct file *file)
289{
290	if (expect_close == 42)
291		wdt_disable();
292	else {
293		printk(KERN_CRIT PFX
294			"Unexpected close, not stopping watchdog!\n");
295		wdt_ping();
296	}
297	expect_close = 0;
298	clear_bit(0, &wdt_is_open);
299	return 0;
300}
301
302/*
303 *	Notifier for system down
304 */
305
306static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
307	void *unused)
308{
309	if (code == SYS_DOWN || code == SYS_HALT)
310		wdt_disable();	/* Turn the WDT off */
311
312	return NOTIFY_DONE;
313}
314
315/*
316 *	Kernel Interfaces
317 */
318
319static const struct file_operations wdt_fops = {
320	.owner		= THIS_MODULE,
321	.llseek		= no_llseek,
322	.write		= wdt_write,
323	.unlocked_ioctl	= wdt_ioctl,
324	.open		= wdt_open,
325	.release	= wdt_close,
326};
327
328static struct miscdevice wdt_miscdev = {
329	.minor = WATCHDOG_MINOR,
330	.name = "watchdog",
331	.fops = &wdt_fops,
332};
333
334/*
335 *	The WDT needs to learn about soft shutdowns in order to
336 *	turn the timebomb registers off.
337 */
338
339static struct notifier_block wdt_notifier = {
340	.notifier_call = wdt_notify_sys,
341};
342
343static int __init wdt_init(void)
344{
345	int ret;
346
347	printk(KERN_INFO "WDT driver for the Winbond(TM) W83627HF/THF/HG/DHG Super I/O chip initialising.\n");
348
349	if (wdt_set_heartbeat(timeout)) {
350		wdt_set_heartbeat(WATCHDOG_TIMEOUT);
351		printk(KERN_INFO PFX
352		     "timeout value must be 1 <= timeout <= 255, using %d\n",
353				WATCHDOG_TIMEOUT);
354	}
355
356	if (!request_region(wdt_io, 1, WATCHDOG_NAME)) {
357		printk(KERN_ERR PFX "I/O address 0x%04x already in use\n",
358			wdt_io);
359		ret = -EIO;
360		goto out;
361	}
362
363	w83627hf_init();
364
365	ret = register_reboot_notifier(&wdt_notifier);
366	if (ret != 0) {
367		printk(KERN_ERR PFX
368			"cannot register reboot notifier (err=%d)\n", ret);
369		goto unreg_regions;
370	}
371
372	ret = misc_register(&wdt_miscdev);
373	if (ret != 0) {
374		printk(KERN_ERR PFX
375			"cannot register miscdev on minor=%d (err=%d)\n",
376							WATCHDOG_MINOR, ret);
377		goto unreg_reboot;
378	}
379
380	printk(KERN_INFO PFX
381			"initialized. timeout=%d sec (nowayout=%d)\n",
382							timeout, nowayout);
383
384out:
385	return ret;
386unreg_reboot:
387	unregister_reboot_notifier(&wdt_notifier);
388unreg_regions:
389	release_region(wdt_io, 1);
390	goto out;
391}
392
393static void __exit wdt_exit(void)
394{
395	misc_deregister(&wdt_miscdev);
396	unregister_reboot_notifier(&wdt_notifier);
397	release_region(wdt_io, 1);
398}
399
400module_init(wdt_init);
401module_exit(wdt_exit);
402
403MODULE_LICENSE("GPL");
404MODULE_AUTHOR("Pádraig  Brady <P@draigBrady.com>");
405MODULE_DESCRIPTION("w83627hf/thf WDT driver");
406MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
407