1/*
2 *	ICP Wafer 5823 Single Board Computer WDT driver
3 *      http://www.icpamerica.com/wafer_5823.php
4 *      May also work on other similar models
5 *
6 *	(c) Copyright 2002 Justin Cormack <justin@street-vision.com>
7 *
8 *      Release 0.02
9 *
10 *	Based on advantechwdt.c which is based on wdt.c.
11 *	Original copyright messages:
12 *
13 *	(c) Copyright 1996-1997 Alan Cox <alan@redhat.com>, All Rights Reserved.
14 *				http://www.redhat.com
15 *
16 *	This program is free software; you can redistribute it and/or
17 *	modify it under the terms of the GNU General Public License
18 *	as published by the Free Software Foundation; either version
19 *	2 of the License, or (at your option) any later version.
20 *
21 *	Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
22 *	warranty for any of this software. This material is provided
23 *	"AS-IS" and at no charge.
24 *
25 *	(c) Copyright 1995    Alan Cox <alan@lxorguk.ukuu.org.uk>
26 *
27 */
28
29#include <linux/module.h>
30#include <linux/moduleparam.h>
31#include <linux/miscdevice.h>
32#include <linux/watchdog.h>
33#include <linux/fs.h>
34#include <linux/ioport.h>
35#include <linux/notifier.h>
36#include <linux/reboot.h>
37#include <linux/init.h>
38#include <linux/spinlock.h>
39#include <asm/io.h>
40#include <asm/uaccess.h>
41
42#define WATCHDOG_NAME "Wafer 5823 WDT"
43#define PFX WATCHDOG_NAME ": "
44#define WD_TIMO 60			/* 60 sec default timeout */
45
46static unsigned long wafwdt_is_open;
47static char expect_close;
48static spinlock_t wafwdt_lock;
49
50/*
51 *	You must set these - there is no sane way to probe for this board.
52 *
53 *      To enable, write the timeout value in seconds (1 to 255) to I/O
54 *      port WDT_START, then read the port to start the watchdog. To pat
55 *      the dog, read port WDT_STOP to stop the timer, then read WDT_START
56 *      to restart it again.
57 */
58
59static int wdt_stop = 0x843;
60static int wdt_start = 0x443;
61
62static int timeout = WD_TIMO;  /* in seconds */
63module_param(timeout, int, 0);
64MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. 1<= timeout <=255, default=" __MODULE_STRING(WD_TIMO) ".");
65
66static int nowayout = WATCHDOG_NOWAYOUT;
67module_param(nowayout, int, 0);
68MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
69
70static void wafwdt_ping(void)
71{
72	/* pat watchdog */
73	spin_lock(&wafwdt_lock);
74	inb_p(wdt_stop);
75	inb_p(wdt_start);
76	spin_unlock(&wafwdt_lock);
77}
78
79static void wafwdt_start(void)
80{
81	/* start up watchdog */
82	outb_p(timeout, wdt_start);
83	inb_p(wdt_start);
84}
85
86static void
87wafwdt_stop(void)
88{
89	/* stop watchdog */
90	inb_p(wdt_stop);
91}
92
93static ssize_t wafwdt_write(struct file *file, const char __user *buf, size_t count, loff_t * ppos)
94{
95	/* See if we got the magic character 'V' and reload the timer */
96	if (count) {
97		if (!nowayout) {
98			size_t i;
99
100			/* In case it was set long ago */
101			expect_close = 0;
102
103			/* scan to see whether or not we got the magic character */
104			for (i = 0; i != count; i++) {
105				char c;
106				if (get_user(c, buf + i))
107					return -EFAULT;
108				if (c == 'V')
109					expect_close = 42;
110			}
111		}
112		/* Well, anyhow someone wrote to us, we should return that favour */
113		wafwdt_ping();
114	}
115	return count;
116}
117
118static int wafwdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
119	     unsigned long arg)
120{
121	int new_timeout;
122	void __user *argp = (void __user *)arg;
123	int __user *p = argp;
124	static struct watchdog_info ident = {
125		.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
126		.firmware_version = 1,
127		.identity = "Wafer 5823 WDT",
128	};
129
130	switch (cmd) {
131	case WDIOC_GETSUPPORT:
132		if (copy_to_user(argp, &ident, sizeof (ident)))
133			return -EFAULT;
134		break;
135
136	case WDIOC_GETSTATUS:
137	case WDIOC_GETBOOTSTATUS:
138		return put_user(0, p);
139
140	case WDIOC_KEEPALIVE:
141		wafwdt_ping();
142		break;
143
144	case WDIOC_SETTIMEOUT:
145		if (get_user(new_timeout, p))
146			return -EFAULT;
147		if ((new_timeout < 1) || (new_timeout > 255))
148			return -EINVAL;
149		timeout = new_timeout;
150		wafwdt_stop();
151		wafwdt_start();
152		/* Fall */
153	case WDIOC_GETTIMEOUT:
154		return put_user(timeout, p);
155
156	case WDIOC_SETOPTIONS:
157	{
158		int options, retval = -EINVAL;
159
160		if (get_user(options, p))
161			return -EFAULT;
162
163		if (options & WDIOS_DISABLECARD) {
164			wafwdt_start();
165			retval = 0;
166		}
167
168		if (options & WDIOS_ENABLECARD) {
169			wafwdt_stop();
170			retval = 0;
171		}
172
173		return retval;
174	}
175
176	default:
177		return -ENOTTY;
178	}
179	return 0;
180}
181
182static int wafwdt_open(struct inode *inode, struct file *file)
183{
184	if (test_and_set_bit(0, &wafwdt_is_open))
185		return -EBUSY;
186
187	/*
188	 *      Activate
189	 */
190	wafwdt_start();
191	return nonseekable_open(inode, file);
192}
193
194static int
195wafwdt_close(struct inode *inode, struct file *file)
196{
197	if (expect_close == 42) {
198		wafwdt_stop();
199	} else {
200		printk(KERN_CRIT PFX "WDT device closed unexpectedly.  WDT will not stop!\n");
201		wafwdt_ping();
202	}
203	clear_bit(0, &wafwdt_is_open);
204	expect_close = 0;
205	return 0;
206}
207
208/*
209 *	Notifier for system down
210 */
211
212static int wafwdt_notify_sys(struct notifier_block *this, unsigned long code, void *unused)
213{
214	if (code == SYS_DOWN || code == SYS_HALT) {
215		/* Turn the WDT off */
216		wafwdt_stop();
217	}
218	return NOTIFY_DONE;
219}
220
221/*
222 *	Kernel Interfaces
223 */
224
225static const struct file_operations wafwdt_fops = {
226	.owner		= THIS_MODULE,
227	.llseek		= no_llseek,
228	.write		= wafwdt_write,
229	.ioctl		= wafwdt_ioctl,
230	.open		= wafwdt_open,
231	.release	= wafwdt_close,
232};
233
234static struct miscdevice wafwdt_miscdev = {
235	.minor	= WATCHDOG_MINOR,
236	.name	= "watchdog",
237	.fops	= &wafwdt_fops,
238};
239
240/*
241 *	The WDT needs to learn about soft shutdowns in order to
242 *	turn the timebomb registers off.
243 */
244
245static struct notifier_block wafwdt_notifier = {
246	.notifier_call = wafwdt_notify_sys,
247};
248
249static int __init wafwdt_init(void)
250{
251	int ret;
252
253	printk(KERN_INFO "WDT driver for Wafer 5823 single board computer initialising.\n");
254
255	spin_lock_init(&wafwdt_lock);
256
257	if (timeout < 1 || timeout > 255) {
258		timeout = WD_TIMO;
259		printk (KERN_INFO PFX "timeout value must be 1<=x<=255, using %d\n",
260			timeout);
261	}
262
263	if (wdt_stop != wdt_start) {
264		if(!request_region(wdt_stop, 1, "Wafer 5823 WDT")) {
265			printk (KERN_ERR PFX "I/O address 0x%04x already in use\n",
266			wdt_stop);
267			ret = -EIO;
268			goto error;
269		}
270	}
271
272	if(!request_region(wdt_start, 1, "Wafer 5823 WDT")) {
273		printk (KERN_ERR PFX "I/O address 0x%04x already in use\n",
274			wdt_start);
275		ret = -EIO;
276		goto error2;
277	}
278
279	ret = register_reboot_notifier(&wafwdt_notifier);
280	if (ret != 0) {
281		printk (KERN_ERR PFX "cannot register reboot notifier (err=%d)\n",
282			ret);
283		goto error3;
284	}
285
286	ret = misc_register(&wafwdt_miscdev);
287	if (ret != 0) {
288		printk (KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n",
289			WATCHDOG_MINOR, ret);
290		goto error4;
291	}
292
293	printk (KERN_INFO PFX "initialized. timeout=%d sec (nowayout=%d)\n",
294		timeout, nowayout);
295
296	return ret;
297error4:
298	unregister_reboot_notifier(&wafwdt_notifier);
299error3:
300	release_region(wdt_start, 1);
301error2:
302	if (wdt_stop != wdt_start)
303		release_region(wdt_stop, 1);
304error:
305	return ret;
306}
307
308static void __exit wafwdt_exit(void)
309{
310	misc_deregister(&wafwdt_miscdev);
311	unregister_reboot_notifier(&wafwdt_notifier);
312	if(wdt_stop != wdt_start)
313		release_region(wdt_stop, 1);
314	release_region(wdt_start, 1);
315}
316
317module_init(wafwdt_init);
318module_exit(wafwdt_exit);
319
320MODULE_AUTHOR("Justin Cormack");
321MODULE_DESCRIPTION("ICP Wafer 5823 Single Board Computer WDT driver");
322MODULE_LICENSE("GPL");
323MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
324
325/* end of wafer5823wdt.c */
326