summaryrefslogtreecommitdiffstats
path: root/drivers/watchdog/w83697hf_wdt.c
blob: d9e821d08deb3b7ea21b36be0ec4682389e807e5 (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
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
/*
 *	w83697hf/hg WDT driver
 *
 *	(c) Copyright 2006 Samuel Tardieu <sam@rfc1149.net>
 *	(c) Copyright 2006 Marcus Junker <junker@anduras.de>
 *
 *	Based on w83627hf_wdt.c which is based on advantechwdt.c
 *	which is based on wdt.c.
 *	Original copyright messages:
 *
 *	(c) Copyright 2003 Pádraig Brady <P@draigBrady.com>
 *
 *	(c) Copyright 2000-2001 Marek Michalkiewicz <marekm@linux.org.pl>
 *
 *	(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 Marcus Junker nor ANDURAS AG admit liability nor provide
 *	warranty for any of this software. This material is provided
 *	"AS-IS" and at no charge.
 */

#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 <linux/spinlock.h>

#include <asm/io.h>
#include <asm/uaccess.h>
#include <asm/system.h>

#define WATCHDOG_NAME "w83697hf/hg WDT"
#define PFX WATCHDOG_NAME ": "
#define WATCHDOG_TIMEOUT 60		/* 60 sec default timeout */

static unsigned long wdt_is_open;
static char expect_close;
static spinlock_t io_lock;

/* You must set this - there is no sane way to probe for this board. */
static int wdt_io = 0x2e;
module_param(wdt_io, int, 0);
MODULE_PARM_DESC(wdt_io, "w83697hf/hg WDT io port (default 0x2e, 0 = autodetect)");

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

/*
 *	Kernel methods.
 */

#define W83697HF_EFER (wdt_io+0)	/* Extended Function Enable Register */
#define W83697HF_EFIR (wdt_io+0)	/* Extended Function Index Register (same as EFER) */
#define W83697HF_EFDR (wdt_io+1)	/* Extended Function Data Register */

static inline void
w83697hf_unlock(void)
{
	outb_p(0x87, W83697HF_EFER);	/* Enter extended function mode */
	outb_p(0x87, W83697HF_EFER);	/* Again according to manual */
}

static inline void
w83697hf_lock(void)
{
	outb_p(0xAA, W83697HF_EFER);	/* Leave extended function mode */
}

/*
 *	The three functions w83697hf_get_reg(), w83697hf_set_reg() and
 *	w83697hf_write_timeout() must be called with the device unlocked.
 */

static unsigned char
w83697hf_get_reg(unsigned char reg)
{
	outb_p(reg, W83697HF_EFIR);
	return inb_p(W83697HF_EFDR);
}

static void
w83697hf_set_reg(unsigned char reg, unsigned char data)
{
	outb_p(reg, W83697HF_EFIR);
	outb_p(data, W83697HF_EFDR);
}

static void
w83697hf_write_timeout(int timeout)
{
	w83697hf_set_reg(0xF4, timeout);	/* Write Timeout counter to CRF4 */
}

static void
w83697hf_select_wdt(void)
{
	w83697hf_unlock();
	w83697hf_set_reg(0x07, 0x08);	/* Switch to logic device 8 (GPIO2) */
}

static inline void
w83697hf_deselect_wdt(void)
{
	w83697hf_lock();
}

static void
w83697hf_init(void)
{
	unsigned char bbuf;

	w83697hf_select_wdt();

	bbuf = w83697hf_get_reg(0x29);
	bbuf &= ~0x60;
	bbuf |= 0x20;
	w83697hf_set_reg(0x29, bbuf);	/* Set pin 119 to WDTO# mode (= CR29, WDT0) */

	bbuf = w83697hf_get_reg(0xF3);
	bbuf &= ~0x04;
	w83697hf_set_reg(0xF3, bbuf);	/* Count mode is seconds */

	w83697hf_deselect_wdt();
}

static int
wdt_ping(void)
{
	spin_lock(&io_lock);
	w83697hf_select_wdt();

	w83697hf_write_timeout(timeout);

	w83697hf_deselect_wdt();
	spin_unlock(&io_lock);
	return 0;
}

static int
wdt_enable(void)
{
	spin_lock(&io_lock);
	w83697hf_select_wdt();

	w83697hf_write_timeout(timeout);
	w83697hf_set_reg(0x30, 1);	/* Enable timer */

	w83697hf_deselect_wdt();
	spin_unlock(&io_lock);
	return 0;
}

static int
wdt_disable(void)
{
	spin_lock(&io_lock);
	w83697hf_select_wdt();

	w83697hf_set_reg(0x30, 0);	/* Disable timer */
	w83697hf_write_timeout(0);

	w83697hf_deselect_wdt();
	spin_unlock(&io_lock);
	return 0;
}

static int
wdt_set_heartbeat(int t)
{
	if ((t < 1) || (t > 255))
		return -EINVAL;

	timeout = t;
	return 0;
}

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

			expect_close = 0;

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

static int
wdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
	  unsigned long arg)
{
	void __user *argp = (void __user *)arg;
	int __user *p = argp;
	int new_timeout;
	static struct watchdog_info ident = {
		.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
		.firmware_version = 1,
		.identity = "W83697HF 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:
		wdt_ping();
		break;

	case WDIOC_SETTIMEOUT:
		if (get_user(new_timeout, p))
			return -EFAULT;
		if (wdt_set_heartbeat(new_timeout))
			return -EINVAL;
		wdt_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) {
			wdt_disable();
			retval = 0;
		}

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

		return retval;
	}

	default:
		return -ENOTTY;
	}
	return 0;
}

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

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

static int
wdt_close(struct inode *inode, struct file *file)
{
	if (expect_close == 42) {
		wdt_disable();
	} else {
		printk (KERN_CRIT PFX "Unexpected close, not stopping watchdog!\n");
		wdt_ping();
	}
	expect_close = 0;
	clear_bit(0, &wdt_is_open);
	return 0;
}

/*
 *	Notifier for system down
 */

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

/*
 *	Kernel Interfaces
 */

static const struct file_operations wdt_fops = {
	.owner		= THIS_MODULE,
	.llseek		= no_llseek,
	.write		= wdt_write,
	.ioctl		= wdt_ioctl,
	.open		= wdt_open,
	.release	= wdt_close,
};

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

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

static struct notifier_block wdt_notifier = {
	.notifier_call = wdt_notify_sys,
};

static int
w83697hf_check_wdt(void)
{
	if (!request_region(wdt_io, 2, WATCHDOG_NAME)) {
		printk (KERN_ERR PFX "I/O address 0x%x already in use\n", wdt_io);
		return -EIO;
	}

	printk (KERN_DEBUG PFX "Looking for watchdog at address 0x%x\n", wdt_io);
	w83697hf_unlock();
	if (w83697hf_get_reg(0x20) == 0x60) {
		printk (KERN_INFO PFX "watchdog found at address 0x%x\n", wdt_io);
		w83697hf_lock();
		return 0;
	}
	w83697hf_lock();	/* Reprotect in case it was a compatible device */

	printk (KERN_INFO PFX "watchdog not found at address 0x%x\n", wdt_io);
	release_region(wdt_io, 2);
	return -EIO;
}

static int w83697hf_ioports[] = { 0x2e, 0x4e, 0x00 };

static int __init
wdt_init(void)
{
	int ret, i, found = 0;

	spin_lock_init(&io_lock);

	printk (KERN_INFO PFX "WDT driver for W83697HF/HG initializing\n");

	if (wdt_io == 0) {
		/* we will autodetect the W83697HF/HG watchdog */
		for (i = 0; ((!found) && (w83697hf_ioports[i] != 0)); i++) {
			wdt_io = w83697hf_ioports[i];
			if (!w83697hf_check_wdt())
				found++;
		}
	} else {
		if (!w83697hf_check_wdt())
			found++;
	}

	if (!found) {
		printk (KERN_ERR PFX "No W83697HF/HG could be found\n");
		ret = -EIO;
		goto out;
	}

	w83697hf_init();
	wdt_disable();	/* Disable watchdog until first use */

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

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

	ret = misc_register(&wdt_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(&wdt_notifier);
unreg_regions:
	release_region(wdt_io, 2);
	goto out;
}

static void __exit
wdt_exit(void)
{
	misc_deregister(&wdt_miscdev);
	unregister_reboot_notifier(&wdt_notifier);
	release_region(wdt_io, 2);
}

module_init(wdt_init);
module_exit(wdt_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Marcus Junker <junker@anduras.de>, Samuel Tardieu <sam@rfc1149.net>");
MODULE_DESCRIPTION("w83697hf/hg WDT driver");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
OpenPOWER on IntegriCloud