aboutsummaryrefslogtreecommitdiff
path: root/drivers/watchdog/wdt.c
blob: 64079d933c6349f57ebe4b42bbcbe8217c62201a (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
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
/*
 *	Industrial Computer Source WDT501 driver
 *
 *	(c) Copyright 1996-1997 Alan Cox <alan@lxorguk.ukuu.org.uk>,
 *						All Rights Reserved.
 *
 *	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>
 *
 *	Release 0.10.
 *
 *	Fixes
 *		Dave Gregorich	:	Modularisation and minor bugs
 *		Alan Cox	:	Added the watchdog ioctl() stuff
 *		Alan Cox	:	Fixed the reboot problem (as noted by
 *					Matt Crocker).
 *		Alan Cox	:	Added wdt= boot option
 *		Alan Cox	:	Cleaned up copy/user stuff
 *		Tim Hockin	:	Added insmod parameters, comment
 *					cleanup, parameterized timeout
 *		Tigran Aivazian	:	Restructured wdt_init() to handle
 *					failures
 *		Joel Becker	:	Added WDIOC_GET/SETTIMEOUT
 *		Matt Domsch	:	Added nowayout module option
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/interrupt.h>
#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/io.h>
#include <linux/uaccess.h>

#include <asm/system.h>
#include "wd501p.h"

static unsigned long wdt_is_open;
static char expect_close;

/*
 *	Module parameters
 */

#define WD_TIMO 60			/* Default heartbeat = 60 seconds */

static int heartbeat = WD_TIMO;
static int wd_heartbeat;
module_param(heartbeat, int, 0);
MODULE_PARM_DESC(heartbeat,
	"Watchdog heartbeat in seconds. (0 < heartbeat < 65536, default="
				__MODULE_STRING(WD_TIMO) ")");

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

/* You must set these - there is no sane way to probe for this board. */
static int io = 0x240;
static int irq = 11;

static DEFINE_SPINLOCK(wdt_lock);

module_param(io, int, 0);
MODULE_PARM_DESC(io, "WDT io port (default=0x240)");
module_param(irq, int, 0);
MODULE_PARM_DESC(irq, "WDT irq (default=11)");

/* Support for the Fan Tachometer on the WDT501-P */
static int tachometer;
module_param(tachometer, int, 0);
MODULE_PARM_DESC(tachometer,
		"WDT501-P Fan Tachometer support (0=disable, default=0)");

static int type = 500;
module_param(type, int, 0);
MODULE_PARM_DESC(type,
		"WDT501-P Card type (500 or 501, default=500)");

/*
 *	Programming support
 */

static void wdt_ctr_mode(int ctr, int mode)
{
	ctr <<= 6;
	ctr |= 0x30;
	ctr |= (mode << 1);
	outb_p(ctr, WDT_CR);
}

static void wdt_ctr_load(int ctr, int val)
{
	outb_p(val&0xFF, WDT_COUNT0+ctr);
	outb_p(val>>8, WDT_COUNT0+ctr);
}

/**
 *	wdt_start:
 *
 *	Start the watchdog driver.
 */

static int wdt_start(void)
{
	unsigned long flags;
	spin_lock_irqsave(&wdt_lock, flags);
	inb_p(WDT_DC);			/* Disable watchdog */
	wdt_ctr_mode(0, 3);		/* Program CTR0 for Mode 3:
						Square Wave Generator */
	wdt_ctr_mode(1, 2);		/* Program CTR1 for Mode 2:
						Rate Generator */
	wdt_ctr_mode(2, 0);		/* Program CTR2 for Mode 0:
						Pulse on Terminal Count */
	wdt_ctr_load(0, 8948);		/* Count at 100Hz */
	wdt_ctr_load(1, wd_heartbeat);	/* Heartbeat */
	wdt_ctr_load(2, 65535);		/* Length of reset pulse */
	outb_p(0, WDT_DC);		/* Enable watchdog */
	spin_unlock_irqrestore(&wdt_lock, flags);
	return 0;
}

/**
 *	wdt_stop:
 *
 *	Stop the watchdog driver.
 */

static int wdt_stop(void)
{
	unsigned long flags;
	spin_lock_irqsave(&wdt_lock, flags);
	/* Turn the card off */
	inb_p(WDT_DC);			/* Disable watchdog */
	wdt_ctr_load(2, 0);		/* 0 length reset pulses now */
	spin_unlock_irqrestore(&wdt_lock, flags);
	return 0;
}

/**
 *	wdt_ping:
 *
 *	Reload counter one with the watchdog heartbeat. We don't bother
 *	reloading the cascade counter.
 */

static void wdt_ping(void)
{
	unsigned long flags;
	spin_lock_irqsave(&wdt_lock, flags);
	/* Write a watchdog value */
	inb_p(WDT_DC);			/* Disable watchdog */
	wdt_ctr_mode(1, 2);		/* Re-Program CTR1 for Mode 2:
							Rate Generator */
	wdt_ctr_load(1, wd_heartbeat);	/* Heartbeat */
	outb_p(0, WDT_DC);		/* Enable watchdog */
	spin_unlock_irqrestore(&wdt_lock, flags);
}

/**
 *	wdt_set_heartbeat:
 *	@t:		the new heartbeat value that needs to be set.
 *
 *	Set a new heartbeat value for the watchdog device. If the heartbeat
 *	value is incorrect we keep the old value and return -EINVAL. If
 *	successful we return 0.
 */

static int wdt_set_heartbeat(int t)
{
	if (t < 1 || t > 65535)
		return -EINVAL;

	heartbeat = t;
	wd_heartbeat = t * 100;
	return 0;
}

/**
 *	wdt_get_status:
 *
 *	Extract the status information from a WDT watchdog device. There are
 *	several board variants so we have to know which bits are valid. Some
 *	bits default to one and some to zero in order to be maximally painful.
 *
 *	we then map the bits onto the status ioctl flags.
 */

static int wdt_get_status(void)
{
	unsigned char new_status;
	int status = 0;
	unsigned long flags;

	spin_lock_irqsave(&wdt_lock, flags);
	new_status = inb_p(WDT_SR);
	spin_unlock_irqrestore(&wdt_lock, flags);

	if (new_status & WDC_SR_ISOI0)
		status |= WDIOF_EXTERN1;
	if (new_status & WDC_SR_ISII1)
		status |= WDIOF_EXTERN2;
	if (type == 501) {
		if (!(new_status & WDC_SR_TGOOD))
			status |= WDIOF_OVERHEAT;
		if (!(new_status & WDC_SR_PSUOVER))
			status |= WDIOF_POWEROVER;
		if (!(new_status & WDC_SR_PSUUNDR))
			status |= WDIOF_POWERUNDER;
		if (tachometer) {
			if (!(new_status & WDC_SR_FANGOOD))
				status |= WDIOF_FANFAULT;
		}
	}
	return status;
}

/**
 *	wdt_get_temperature:
 *
 *	Reports the temperature in degrees Fahrenheit. The API is in
 *	farenheit. It was designed by an imperial measurement luddite.
 */

static int wdt_get_temperature(void)
{
	unsigned short c;
	unsigned long flags;

	spin_lock_irqsave(&wdt_lock, flags);
	c = inb_p(WDT_RT);
	spin_unlock_irqrestore(&wdt_lock, flags);
	return (c * 11 / 15) + 7;
}

static void wdt_decode_501(int status)
{
	if (!(status & WDC_SR_TGOOD))
		pr_crit("Overheat alarm (%d)\n", inb_p(WDT_RT));
	if (!(status & WDC_SR_PSUOVER))
		pr_crit("PSU over voltage\n");
	if (!(status & WDC_SR_PSUUNDR))
		pr_crit("PSU under voltage\n");
}

/**
 *	wdt_interrupt:
 *	@irq:		Interrupt number
 *	@dev_id:	Unused as we don't allow multiple devices.
 *
 *	Handle an interrupt from the board. These are raised when the status
 *	map changes in what the board considers an interesting way. That means
 *	a failure condition occurring.
 */

static irqreturn_t wdt_interrupt(int irq, void *dev_id)
{
	/*
	 *	Read the status register see what is up and
	 *	then printk it.
	 */
	unsigned char status;

	spin_lock(&wdt_lock);
	status = inb_p(WDT_SR);

	pr_crit("WDT status %d\n", status);

	if (type == 501) {
		wdt_decode_501(status);
		if (tachometer) {
			if (!(status & WDC_SR_FANGOOD))
				pr_crit("Possible fan fault\n");
		}
	}
	if (!(status & WDC_SR_WCCR)) {
#ifdef SOFTWARE_REBOOT
#ifdef ONLY_TESTING
		pr_crit("Would Reboot\n");
#else
		pr_crit("Initiating system reboot\n");
		emergency_restart();
#endif
#else
		pr_crit("Reset in 5ms\n");
#endif
	}
	spin_unlock(&wdt_lock);
	return IRQ_HANDLED;
}


/**
 *	wdt_write:
 *	@file: file handle to the watchdog
 *	@buf: buffer to write (unused as data does not matter here
 *	@count: count of bytes
 *	@ppos: pointer to the position to write. No seeks allowed
 *
 *	A write to a watchdog device is defined as a keepalive signal. Any
 *	write of data will do, as we we don't define content meaning.
 */

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;

			/* In case it was set long ago */
			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;
}

/**
 *	wdt_ioctl:
 *	@file: file handle to the device
 *	@cmd: watchdog command
 *	@arg: argument pointer
 *
 *	The watchdog API defines a common set of functions for all watchdogs
 *	according to their available features. We only actually usefully support
 *	querying capabilities and current status.
 */

static long wdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
	void __user *argp = (void __user *)arg;
	int __user *p = argp;
	int new_heartbeat;
	int status;

	struct watchdog_info ident = {
		.options =		WDIOF_SETTIMEOUT|
					WDIOF_MAGICCLOSE|
					WDIOF_KEEPALIVEPING,
		.firmware_version =	1,
		.identity =		"WDT500/501",
	};

	/* Add options according to the card we have */
	ident.options |= (WDIOF_EXTERN1|WDIOF_EXTERN2);
	if (type == 501) {
		ident.options |= (WDIOF_OVERHEAT|WDIOF_POWERUNDER|
							WDIOF_POWEROVER);
		if (tachometer)
			ident.options |= WDIOF_FANFAULT;
	}

	switch (cmd) {
	case WDIOC_GETSUPPORT:
		return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
	case WDIOC_GETSTATUS:
		status = wdt_get_status();
		return put_user(status, p);
	case WDIOC_GETBOOTSTATUS:
		return put_user(0, p);
	case WDIOC_KEEPALIVE:
		wdt_ping();
		return 0;
	case WDIOC_SETTIMEOUT:
		if (get_user(new_heartbeat, p))
			return -EFAULT;
		if (wdt_set_heartbeat(new_heartbeat))
			return -EINVAL;
		wdt_ping();
		/* Fall */
	case WDIOC_GETTIMEOUT:
		return put_user(heartbeat, p);
	default:
		return -ENOTTY;
	}
}

/**
 *	wdt_open:
 *	@inode: inode of device
 *	@file: file handle to device
 *
 *	The watchdog device has been opened. The watchdog device is single
 *	open and on opening we load the counters. Counter zero is a 100Hz
 *	cascade, into counter 1 which downcounts to reboot. When the counter
 *	triggers counter 2 downcounts the length of the reset pulse which
 *	set set to be as long as possible.
 */

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

/**
 *	wdt_release:
 *	@inode: inode to board
 *	@file: file handle to board
 *
 *	The watchdog has a configurable API. There is a religious dispute
 *	between people who want their watchdog to be able to shut down and
 *	those who want to be sure if the watchdog manager dies the machine
 *	reboots. In the former case we disable the counters, in the latter
 *	case you have to open it again very soon.
 */

static int wdt_release(struct inode *inode, struct file *file)
{
	if (expect_close == 42) {
		wdt_stop();
		clear_bit(0, &wdt_is_open);
	} else {
		pr_crit("WDT device closed unexpectedly.  WDT will not stop!\n");
		wdt_ping();
	}
	expect_close = 0;
	return 0;
}

/**
 *	wdt_temp_read:
 *	@file: file handle to the watchdog board
 *	@buf: buffer to write 1 byte into
 *	@count: length of buffer
 *	@ptr: offset (no seek allowed)
 *
 *	Temp_read reports the temperature in degrees Fahrenheit. The API is in
 *	farenheit. It was designed by an imperial measurement luddite.
 */

static ssize_t wdt_temp_read(struct file *file, char __user *buf,
						size_t count, loff_t *ptr)
{
	int temperature = wdt_get_temperature();

	if (copy_to_user(buf, &temperature, 1))
		return -EFAULT;

	return 1;
}

/**
 *	wdt_temp_open:
 *	@inode: inode of device
 *	@file: file handle to device
 *
 *	The temperature device has been opened.
 */

static int wdt_temp_open(struct inode *inode, struct file *file)
{
	return nonseekable_open(inode, file);
}

/**
 *	wdt_temp_release:
 *	@inode: inode to board
 *	@file: file handle to board
 *
 *	The temperature device has been closed.
 */

static int wdt_temp_release(struct inode *inode, struct file *file)
{
	return 0;
}

/**
 *	notify_sys:
 *	@this: our notifier block
 *	@code: the event being reported
 *	@unused: unused
 *
 *	Our notifier is called on system shutdowns. We want to turn the card
 *	off at reboot otherwise the machine will reboot again during memory
 *	test or worse yet during the following fsck. This would suck, in fact
 *	trust me - if it happens it does suck.
 */

static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
	void *unused)
{
	if (code == SYS_DOWN || code == SYS_HALT)
		wdt_stop();
	return NOTIFY_DONE;
}

/*
 *	Kernel Interfaces
 */


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

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

static const struct file_operations wdt_temp_fops = {
	.owner		= THIS_MODULE,
	.llseek		= no_llseek,
	.read		= wdt_temp_read,
	.open		= wdt_temp_open,
	.release	= wdt_temp_release,
};

static struct miscdevice temp_miscdev = {
	.minor	= TEMP_MINOR,
	.name	= "temperature",
	.fops	= &wdt_temp_fops,
};

/*
 *	The WDT card 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,
};

/**
 *	cleanup_module:
 *
 *	Unload the watchdog. You cannot do this with any file handles open.
 *	If your watchdog is set to continue ticking on close and you unload
 *	it, well it keeps ticking. We won't get the interrupt but the board
 *	will not touch PC memory so all is fine. You just have to load a new
 *	module in 60 seconds or reboot.
 */

static void __exit wdt_exit(void)
{
	misc_deregister(&wdt_miscdev);
	if (type == 501)
		misc_deregister(&temp_miscdev);
	unregister_reboot_notifier(&wdt_notifier);
	free_irq(irq, NULL);
	release_region(io, 8);
}

/**
 *	wdt_init:
 *
 *	Set up the WDT watchdog board. All we have to do is grab the
 *	resources we require and bitch if anyone beat us to them.
 *	The open() function will actually kick the board off.
 */

static int __init wdt_init(void)
{
	int ret;

	if (type != 500 && type != 501) {
		pr_err("unknown card type '%d'\n", type);
		return -ENODEV;
	}

	/* Check that the heartbeat value is within it's range;
	   if not reset to the default */
	if (wdt_set_heartbeat(heartbeat)) {
		wdt_set_heartbeat(WD_TIMO);
		pr_info("heartbeat value must be 0 < heartbeat < 65536, using %d\n",
			WD_TIMO);
	}

	if (!request_region(io, 8, "wdt501p")) {
		pr_err("I/O address 0x%04x already in use\n", io);
		ret = -EBUSY;
		goto out;
	}

	ret = request_irq(irq, wdt_interrupt, 0, "wdt501p", NULL);
	if (ret) {
		pr_err("IRQ %d is not free\n", irq);
		goto outreg;
	}

	ret = register_reboot_notifier(&wdt_notifier);
	if (ret) {
		pr_err("cannot register reboot notifier (err=%d)\n", ret);
		goto outirq;
	}

	if (type == 501) {
		ret = misc_register(&temp_miscdev);
		if (ret) {
			pr_err("cannot register miscdev on minor=%d (err=%d)\n",
			       TEMP_MINOR, ret);
			goto outrbt;
		}
	}

	ret = misc_register(&wdt_miscdev);
	if (ret) {
		pr_err("cannot register miscdev on minor=%d (err=%d)\n",
		       WATCHDOG_MINOR, ret);
		goto outmisc;
	}

	pr_info("WDT500/501-P driver 0.10 at 0x%04x (Interrupt %d). heartbeat=%d sec (nowayout=%d)\n",
		io, irq, heartbeat, nowayout);
	if (type == 501)
		pr_info("Fan Tachometer is %s\n",
			tachometer ? "Enabled" : "Disabled");
	return 0;

outmisc:
	if (type == 501)
		misc_deregister(&temp_miscdev);
outrbt:
	unregister_reboot_notifier(&wdt_notifier);
outirq:
	free_irq(irq, NULL);
outreg:
	release_region(io, 8);
out:
	return ret;
}

module_init(wdt_init);
module_exit(wdt_exit);

MODULE_AUTHOR("Alan Cox");
MODULE_DESCRIPTION("Driver for ISA ICS watchdog cards (WDT500/501)");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
MODULE_ALIAS_MISCDEV(TEMP_MINOR);
MODULE_LICENSE("GPL");