aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/char/watchdog/advantechwdt.c
blob: 9d732769ba0144bd36a720d4362185dc0bb651d1 (plain) (blame)
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
/*
 *	Advantech Single Board Computer WDT driver
 *
 *	(c) Copyright 2000-2001 Marek Michalkiewicz <marekm@linux.org.pl>
 *
 *	Based on acquirewdt.c which is based on wdt.c.
 *	Original copyright messages:
 *
 *	(c) Copyright 1996 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@redhat.com>
 *
 *	14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com>
 *	    Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT
 *
 *	16-Oct-2002 Rob Radez <rob@osinvestor.com>
 *	    Clean up ioctls, clean up init + exit, add expect close support,
 *	    add wdt_start and wdt_stop as parameters.
 */

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.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 <asm/io.h>
#include <asm/uaccess.h>
#include <asm/system.h>

#define WATCHDOG_NAME "Advantech WDT"
#define PFX WATCHDOG_NAME ": "
#define WATCHDOG_TIMEOUT 60		/* 60 sec default timeout */

static unsigned long advwdt_is_open;
static char adv_expect_close;

/*
 *	You must set these - there is no sane way to probe for this board.
 *
 *	To enable or restart, write the timeout value in seconds (1 to 63)
 *	to I/O port wdt_start.  To disable, read I/O port wdt_stop.
 *	Both are 0x443 for most boards (tested on a PCA-6276VE-00B1), but
 *	check your manual (at least the PCA-6159 seems to be different -
 *	the manual says wdt_stop is 0x43, not 0x443).
 *	(0x43 is also a write-only control register for the 8254 timer!)
 */

static int wdt_stop = 0x443;
module_param(wdt_stop, int, 0);
MODULE_PARM_DESC(wdt_stop, "Advantech WDT 'stop' io port (default 0x443)");

static int wdt_start = 0x443;
module_param(wdt_start, int, 0);
MODULE_PARM_DESC(wdt_start, "Advantech WDT 'start' io port (default 0x443)");

static int timeout = WATCHDOG_TIMEOUT;	/* in seconds */
module_param(timeout, int, 0);
MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. 1<= timeout <=63, default=" __MODULE_STRING(WATCHDOG_TIMEOUT) ".");

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

/*
 *	Kernel methods.
 */

static void
advwdt_ping(void)
{
	/* Write a watchdog value */
	outb_p(timeout, wdt_start);
}

static void
advwdt_disable(void)
{
	inb_p(wdt_stop);
}

static ssize_t
advwdt_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
{
	if (count) {
		if (!nowayout) {
			size_t i;

			adv_expect_close = 0;

			for (i = 0; i != count; i++) {
				char c;
				if (get_user(c, buf+i))
					return -EFAULT;
				if (c == 'V')
					adv_expect_close = 42;
			}
		}
		advwdt_ping();
	}
	return count;
}

static int
advwdt_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 = "Advantech 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:
	  advwdt_ping();
	  break;

	case WDIOC_SETTIMEOUT:
	  if (get_user(new_timeout, p))
		  return -EFAULT;
	  if ((new_timeout < 1) || (new_timeout > 63))
		  return -EINVAL;
	  timeout = new_timeout;
	  advwdt_ping();
	  /* 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) {
	    advwdt_disable();
	    retval = 0;
	  }

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

	  return retval;
	}

	default:
	  return -ENOTTY;
	}
	return 0;
}

static int
advwdt_open(struct inode *inode, struct file *file)
{
	if (test_and_set_bit(0, &advwdt_is_open))
		return -EBUSY;
	/*
	 *	Activate
	 */

	advwdt_ping();
	return nonseekable_open(inode, file);
}

static int
advwdt_close(struct inode *inode, struct file *file)
{
	if (adv_expect_close == 42) {
		advwdt_disable();
	} else {
		printk(KERN_CRIT PFX "Unexpected close, not stopping watchdog!\n");
		advwdt_ping();
	}
	clear_bit(0, &advwdt_is_open);
	adv_expect_close = 0;
	return 0;
}

/*
 *	Notifier for system down
 */

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

/*
 *	Kernel Interfaces
 */

static const struct file_operations advwdt_fops = {
	.owner		= THIS_MODULE,
	.llseek		= no_llseek,
	.write		= advwdt_write,
	.ioctl		= advwdt_ioctl,
	.open		= advwdt_open,
	.release	= advwdt_close,
};

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

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

static struct notifier_block advwdt_notifier = {
	.notifier_call = advwdt_notify_sys,
};

static int __init
advwdt_init(void)
{
	int ret;

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

	if (timeout < 1 || timeout > 63) {
		timeout = WATCHDOG_TIMEOUT;
		printk (KERN_INFO PFX "timeout value must be 1<=x<=63, using %d\n",
			timeout);
	}

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

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

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

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

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

out:
	return ret;
unreg_reboot:
	unregister_reboot_notifier(&advwdt_notifier);
unreg_regions:
	release_region(wdt_start, 1);
unreg_stop:
	if (wdt_stop != wdt_start)
		release_region(wdt_stop, 1);
	goto out;
}

static void __exit
advwdt_exit(void)
{
	misc_deregister(&advwdt_miscdev);
	unregister_reboot_notifier(&advwdt_notifier);
	if(wdt_stop != wdt_start)
		release_region(wdt_stop,1);
	release_region(wdt_start,1);
}

module_init(advwdt_init);
module_exit(advwdt_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Marek Michalkiewicz <marekm@linux.org.pl>");
MODULE_DESCRIPTION("Advantech Single Board Computer WDT driver");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);