summaryrefslogtreecommitdiffstats
path: root/drivers/char/watchdog/wafer5823wdt.c
blob: abb0bea45c02f813d706ff81fd294bcec0d6cbb7 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
/*
 *	ICP Wafer 5823 Single Board Computer WDT driver
 *      http://www.icpamerica.com/wafer_5823.php
 *      May also work on other similar models
 *
 *	(c) Copyright 2002 Justin Cormack <justin@street-vision.com>
 *
 *      Release 0.02
 *
 *	Based on advantechwdt.c which is based on wdt.c.
 *	Original copyright messages:
 *
 *	(c) Copyright 1996-1997 Alan Cox <alan@redhat.com>, All Rights Reserved.
 *				http://www.redhat.com
 *
 *	This program is free software; you can redistribute it and/or
 *	modify it under the terms of the GNU General Public License
 *	as published by the Free Software Foundation; either version
 *	2 of the License, or (at your option) any later version.
 *
 *	Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
 *	warranty for any of this software. This material is provided
 *	"AS-IS" and at no charge.
 *
 *	(c) Copyright 1995    Alan Cox <alan@lxorguk.ukuu.org.uk>
 *
 */

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/fs.h>
#include <linux/ioport.h>
#include <linux/notifier.h>
#include <linux/reboot.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <asm/io.h>
#include <asm/uaccess.h>

#define WATCHDOG_NAME "Wafer 5823 WDT"
#define PFX WATCHDOG_NAME ": "
#define WD_TIMO 60			/* 60 sec default timeout */

static unsigned long wafwdt_is_open;
static char expect_close;
static spinlock_t wafwdt_lock;

/*
 *	You must set these - there is no sane way to probe for this board.
 *
 *      To enable, write the timeout value in seconds (1 to 255) to I/O
 *      port WDT_START, then read the port to start the watchdog. To pat
 *      the dog, read port WDT_STOP to stop the timer, then read WDT_START
 *      to restart it again.
 */

static int wdt_stop = 0x843;
static int wdt_start = 0x443;

static int timeout = WD_TIMO;  /* in seconds */
module_param(timeout, int, 0);
MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. 1<= timeout <=255, default=" __MODULE_STRING(WD_TIMO) ".");

#ifdef CONFIG_WATCHDOG_NOWAYOUT
static int nowayout = 1;
#else
static int nowayout = 0;
#endif

module_param(nowayout, int, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)");

static void wafwdt_ping(void)
{
	/* pat watchdog */
	spin_lock(&wafwdt_lock);
	inb_p(wdt_stop);
	inb_p(wdt_start);
	spin_unlock(&wafwdt_lock);
}

static void wafwdt_start(void)
{
	/* start up watchdog */
	outb_p(timeout, wdt_start);
	inb_p(wdt_start);
}

static void
wafwdt_stop(void)
{
	/* stop watchdog */
	inb_p(wdt_stop);
}

static ssize_t wafwdt_write(struct file *file, const char __user *buf, size_t count, loff_t * ppos)
{
	/* See if we got the magic character 'V' and reload the timer */
	if (count) {
		if (!nowayout) {
			size_t i;

			/* In case it was set long ago */
			expect_close = 0;

			/* scan to see whether or not we got the magic character */
			for (i = 0; i != count; i++) {
				char c;
				if (get_user(c, buf + i))
					return -EFAULT;
				if (c == 'V')
					expect_close = 42;
			}
		}
		/* Well, anyhow someone wrote to us, we should return that favour */
		wafwdt_ping();
	}
	return count;
}

static int wafwdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
	     unsigned long arg)
{
	int new_timeout;
	void __user *argp = (void __user *)arg;
	int __user *p = argp;
	static struct watchdog_info ident = {
		.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
		.firmware_version = 1,
		.identity = "Wafer 5823 WDT",
	};

	switch (cmd) {
	case WDIOC_GETSUPPORT:
		if (copy_to_user(argp, &ident, sizeof (ident)))
			return -EFAULT;
		break;

	case WDIOC_GETSTATUS:
	case WDIOC_GETBOOTSTATUS:
		return put_user(0, p);

	case WDIOC_KEEPALIVE:
		wafwdt_ping();
		break;

	case WDIOC_SETTIMEOUT:
		if (get_user(new_timeout, p))
			return -EFAULT;
		if ((new_timeout < 1) || (new_timeout > 255))
			return -EINVAL;
		timeout = new_timeout;
		wafwdt_stop();
		wafwdt_start();
		/* Fall */
	case WDIOC_GETTIMEOUT:
		return put_user(timeout, p);

	case WDIOC_SETOPTIONS:
	{
		int options, retval = -EINVAL;

		if (get_user(options, p))
			return -EFAULT;

		if (options & WDIOS_DISABLECARD) {
			wafwdt_start();
			retval = 0;
		}

		if (options & WDIOS_ENABLECARD) {
			wafwdt_stop();
			retval = 0;
		}

		return retval;
	}

	default:
		return -ENOIOCTLCMD;
	}
	return 0;
}

static int wafwdt_open(struct inode *inode, struct file *file)
{
	if (test_and_set_bit(0, &wafwdt_is_open))
		return -EBUSY;

	/*
	 *      Activate
	 */
	wafwdt_start();
	return nonseekable_open(inode, file);
}

static int
wafwdt_close(struct inode *inode, struct file *file)
{
	if (expect_close == 42) {
		wafwdt_stop();
	} else {
		printk(KERN_CRIT PFX "WDT device closed unexpectedly.  WDT will not stop!\n");
		wafwdt_ping();
	}
	clear_bit(0, &wafwdt_is_open);
	expect_close = 0;
	return 0;
}

/*
 *	Notifier for system down
 */

static int wafwdt_notify_sys(struct notifier_block *this, unsigned long code, void *unused)
{
	if (code == SYS_DOWN || code == SYS_HALT) {
		/* Turn the WDT off */
		wafwdt_stop();
	}
	return NOTIFY_DONE;
}

/*
 *	Kernel Interfaces
 */

static struct file_operations wafwdt_fops = {
	.owner		= THIS_MODULE,
	.llseek		= no_llseek,
	.write		= wafwdt_write,
	.ioctl		= wafwdt_ioctl,
	.open		= wafwdt_open,
	.release	= wafwdt_close,
};

static struct miscdevice wafwdt_miscdev = {
	.minor	= WATCHDOG_MINOR,
	.name	= "watchdog",
	.fops	= &wafwdt_fops,
};

/*
 *	The WDT needs to learn about soft shutdowns in order to
 *	turn the timebomb registers off.
 */

static struct notifier_block wafwdt_notifier = {
	.notifier_call = wafwdt_notify_sys,
};

static int __init wafwdt_init(void)
{
	int ret;

	printk(KERN_INFO "WDT driver for Wafer 5823 single board computer initialising.\n");

	spin_lock_init(&wafwdt_lock);

	if (timeout < 1 || timeout > 255) {
		timeout = WD_TIMO;
		printk (KERN_INFO PFX "timeout value must be 1<=x<=255, using %d\n",
			timeout);
	}

	if (wdt_stop != wdt_start) {
		if(!request_region(wdt_stop, 1, "Wafer 5823 WDT")) {
			printk (KERN_ERR PFX "I/O address 0x%04x already in use\n",
			wdt_stop);
			ret = -EIO;
			goto error;
		}
	}

	if(!request_region(wdt_start, 1, "Wafer 5823 WDT")) {
		printk (KERN_ERR PFX "I/O address 0x%04x already in use\n",
			wdt_start);
		ret = -EIO;
		goto error2;
	}

	ret = register_reboot_notifier(&wafwdt_notifier);
	if (ret != 0) {
		printk (KERN_ERR PFX "cannot register reboot notifier (err=%d)\n",
			ret);
		goto error3;
	}

	ret = misc_register(&wafwdt_miscdev);
	if (ret != 0) {
		printk (KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n",
			WATCHDOG_MINOR, ret);
		goto error4;
	}

	printk (KERN_INFO PFX "initialized. timeout=%d sec (nowayout=%d)\n",
		timeout, nowayout);

	return ret;
error4:
	unregister_reboot_notifier(&wafwdt_notifier);
error3:
	release_region(wdt_start, 1);
error2:
	if (wdt_stop != wdt_start)
		release_region(wdt_stop, 1);
error:
	return ret;
}

static void __exit wafwdt_exit(void)
{
	misc_deregister(&wafwdt_miscdev);
	unregister_reboot_notifier(&wafwdt_notifier);
	if(wdt_stop != wdt_start)
		release_region(wdt_stop, 1);
	release_region(wdt_start, 1);
}

module_init(wafwdt_init);
module_exit(wafwdt_exit);

MODULE_AUTHOR("Justin Cormack");
MODULE_DESCRIPTION("ICP Wafer 5823 Single Board Computer WDT driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);

/* end of wafer5823wdt.c */