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/drivers/char/watchdog/wdt.c

https://bitbucket.org/evzijst/gittest
C | 647 lines | 358 code | 84 blank | 205 comment | 39 complexity | 9daa35b06e73718e10a361f0ccdb2a50 MD5 | raw file
  1/*
  2 *	Industrial Computer Source WDT500/501 driver
  3 *
  4 *	(c) Copyright 1996-1997 Alan Cox <alan@redhat.com>, All Rights Reserved.
  5 *				http://www.redhat.com
  6 *
  7 *	This program is free software; you can redistribute it and/or
  8 *	modify it under the terms of the GNU General Public License
  9 *	as published by the Free Software Foundation; either version
 10 *	2 of the License, or (at your option) any later version.
 11 *
 12 *	Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
 13 *	warranty for any of this software. This material is provided
 14 *	"AS-IS" and at no charge.
 15 *
 16 *	(c) Copyright 1995    Alan Cox <alan@lxorguk.ukuu.org.uk>
 17 *
 18 *	Release 0.10.
 19 *
 20 *	Fixes
 21 *		Dave Gregorich	:	Modularisation and minor bugs
 22 *		Alan Cox	:	Added the watchdog ioctl() stuff
 23 *		Alan Cox	:	Fixed the reboot problem (as noted by
 24 *					Matt Crocker).
 25 *		Alan Cox	:	Added wdt= boot option
 26 *		Alan Cox	:	Cleaned up copy/user stuff
 27 *		Tim Hockin	:	Added insmod parameters, comment cleanup
 28 *					Parameterized timeout
 29 *		Tigran Aivazian	:	Restructured wdt_init() to handle failures
 30 *		Joel Becker	:	Added WDIOC_GET/SETTIMEOUT
 31 *		Matt Domsch	:	Added nowayout module option
 32 */
 33
 34#include <linux/config.h>
 35#include <linux/interrupt.h>
 36#include <linux/module.h>
 37#include <linux/moduleparam.h>
 38#include <linux/types.h>
 39#include <linux/miscdevice.h>
 40#include <linux/watchdog.h>
 41#include <linux/fs.h>
 42#include <linux/ioport.h>
 43#include <linux/notifier.h>
 44#include <linux/reboot.h>
 45#include <linux/init.h>
 46
 47#include <asm/io.h>
 48#include <asm/uaccess.h>
 49#include <asm/system.h>
 50#include "wd501p.h"
 51
 52static unsigned long wdt_is_open;
 53static char expect_close;
 54
 55/*
 56 *	Module parameters
 57 */
 58
 59#define WD_TIMO 60			/* Default heartbeat = 60 seconds */
 60
 61static int heartbeat = WD_TIMO;
 62static int wd_heartbeat;
 63module_param(heartbeat, int, 0);
 64MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds. (0<heartbeat<65536, default=" __MODULE_STRING(WD_TIMO) ")");
 65
 66#ifdef CONFIG_WATCHDOG_NOWAYOUT
 67static int nowayout = 1;
 68#else
 69static int nowayout = 0;
 70#endif
 71
 72module_param(nowayout, int, 0);
 73MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)");
 74
 75/* You must set these - there is no sane way to probe for this board. */
 76static int io=0x240;
 77static int irq=11;
 78
 79module_param(io, int, 0);
 80MODULE_PARM_DESC(io, "WDT io port (default=0x240)");
 81module_param(irq, int, 0);
 82MODULE_PARM_DESC(irq, "WDT irq (default=11)");
 83
 84#ifdef CONFIG_WDT_501
 85/* Support for the Fan Tachometer on the WDT501-P */
 86static int tachometer;
 87
 88module_param(tachometer, int, 0);
 89MODULE_PARM_DESC(tachometer, "WDT501-P Fan Tachometer support (0=disable, default=0)");
 90#endif /* CONFIG_WDT_501 */
 91
 92/*
 93 *	Programming support
 94 */
 95
 96static void wdt_ctr_mode(int ctr, int mode)
 97{
 98	ctr<<=6;
 99	ctr|=0x30;
100	ctr|=(mode<<1);
101	outb_p(ctr, WDT_CR);
102}
103
104static void wdt_ctr_load(int ctr, int val)
105{
106	outb_p(val&0xFF, WDT_COUNT0+ctr);
107	outb_p(val>>8, WDT_COUNT0+ctr);
108}
109
110/**
111 *	wdt_start:
112 *
113 *	Start the watchdog driver.
114 */
115
116static int wdt_start(void)
117{
118	inb_p(WDT_DC);			/* Disable watchdog */
119	wdt_ctr_mode(0,3);		/* Program CTR0 for Mode 3: Square Wave Generator */
120	wdt_ctr_mode(1,2);		/* Program CTR1 for Mode 2: Rate Generator */
121	wdt_ctr_mode(2,0);		/* Program CTR2 for Mode 0: Pulse on Terminal Count */
122	wdt_ctr_load(0, 8948);		/* Count at 100Hz */
123	wdt_ctr_load(1,wd_heartbeat);	/* Heartbeat */
124	wdt_ctr_load(2,65535);		/* Length of reset pulse */
125	outb_p(0, WDT_DC);		/* Enable watchdog */
126	return 0;
127}
128
129/**
130 *	wdt_stop:
131 *
132 *	Stop the watchdog driver.
133 */
134
135static int wdt_stop (void)
136{
137	/* Turn the card off */
138	inb_p(WDT_DC);			/* Disable watchdog */
139	wdt_ctr_load(2,0);		/* 0 length reset pulses now */
140	return 0;
141}
142
143/**
144 *	wdt_ping:
145 *
146 *	Reload counter one with the watchdog heartbeat. We don't bother reloading
147 *	the cascade counter.
148 */
149
150static int wdt_ping(void)
151{
152	/* Write a watchdog value */
153	inb_p(WDT_DC);			/* Disable watchdog */
154	wdt_ctr_mode(1,2);		/* Re-Program CTR1 for Mode 2: Rate Generator */
155	wdt_ctr_load(1,wd_heartbeat);	/* Heartbeat */
156	outb_p(0, WDT_DC);		/* Enable watchdog */
157	return 0;
158}
159
160/**
161 *	wdt_set_heartbeat:
162 *	@t:		the new heartbeat value that needs to be set.
163 *
164 *	Set a new heartbeat value for the watchdog device. If the heartbeat value is
165 *	incorrect we keep the old value and return -EINVAL. If successfull we
166 *	return 0.
167 */
168static int wdt_set_heartbeat(int t)
169{
170	if ((t < 1) || (t > 65535))
171		return -EINVAL;
172
173	heartbeat = t;
174	wd_heartbeat = t * 100;
175	return 0;
176}
177
178/**
179 *	wdt_get_status:
180 *	@status:		the new status.
181 *
182 *	Extract the status information from a WDT watchdog device. There are
183 *	several board variants so we have to know which bits are valid. Some
184 *	bits default to one and some to zero in order to be maximally painful.
185 *
186 *	we then map the bits onto the status ioctl flags.
187 */
188
189static int wdt_get_status(int *status)
190{
191	unsigned char new_status=inb_p(WDT_SR);
192
193	*status=0;
194	if (new_status & WDC_SR_ISOI0)
195		*status |= WDIOF_EXTERN1;
196	if (new_status & WDC_SR_ISII1)
197		*status |= WDIOF_EXTERN2;
198#ifdef CONFIG_WDT_501
199	if (!(new_status & WDC_SR_TGOOD))
200		*status |= WDIOF_OVERHEAT;
201	if (!(new_status & WDC_SR_PSUOVER))
202		*status |= WDIOF_POWEROVER;
203	if (!(new_status & WDC_SR_PSUUNDR))
204		*status |= WDIOF_POWERUNDER;
205	if (tachometer) {
206		if (!(new_status & WDC_SR_FANGOOD))
207			*status |= WDIOF_FANFAULT;
208	}
209#endif /* CONFIG_WDT_501 */
210	return 0;
211}
212
213#ifdef CONFIG_WDT_501
214/**
215 *	wdt_get_temperature:
216 *
217 *	Reports the temperature in degrees Fahrenheit. The API is in
218 *	farenheit. It was designed by an imperial measurement luddite.
219 */
220
221static int wdt_get_temperature(int *temperature)
222{
223	unsigned short c=inb_p(WDT_RT);
224
225	*temperature = (c * 11 / 15) + 7;
226	return 0;
227}
228#endif /* CONFIG_WDT_501 */
229
230/**
231 *	wdt_interrupt:
232 *	@irq:		Interrupt number
233 *	@dev_id:	Unused as we don't allow multiple devices.
234 *	@regs:		Unused.
235 *
236 *	Handle an interrupt from the board. These are raised when the status
237 *	map changes in what the board considers an interesting way. That means
238 *	a failure condition occurring.
239 */
240
241static irqreturn_t wdt_interrupt(int irq, void *dev_id, struct pt_regs *regs)
242{
243	/*
244	 *	Read the status register see what is up and
245	 *	then printk it.
246	 */
247	unsigned char status=inb_p(WDT_SR);
248
249	printk(KERN_CRIT "WDT status %d\n", status);
250
251#ifdef CONFIG_WDT_501
252	if (!(status & WDC_SR_TGOOD))
253		printk(KERN_CRIT "Overheat alarm.(%d)\n",inb_p(WDT_RT));
254	if (!(status & WDC_SR_PSUOVER))
255		printk(KERN_CRIT "PSU over voltage.\n");
256	if (!(status & WDC_SR_PSUUNDR))
257		printk(KERN_CRIT "PSU under voltage.\n");
258	if (tachometer) {
259		if (!(status & WDC_SR_FANGOOD))
260			printk(KERN_CRIT "Possible fan fault.\n");
261	}
262#endif /* CONFIG_WDT_501 */
263	if (!(status & WDC_SR_WCCR))
264#ifdef SOFTWARE_REBOOT
265#ifdef ONLY_TESTING
266		printk(KERN_CRIT "Would Reboot.\n");
267#else
268		printk(KERN_CRIT "Initiating system reboot.\n");
269		machine_restart(NULL);
270#endif
271#else
272		printk(KERN_CRIT "Reset in 5ms.\n");
273#endif
274	return IRQ_HANDLED;
275}
276
277
278/**
279 *	wdt_write:
280 *	@file: file handle to the watchdog
281 *	@buf: buffer to write (unused as data does not matter here
282 *	@count: count of bytes
283 *	@ppos: pointer to the position to write. No seeks allowed
284 *
285 *	A write to a watchdog device is defined as a keepalive signal. Any
286 *	write of data will do, as we we don't define content meaning.
287 */
288
289static ssize_t wdt_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
290{
291	if(count) {
292		if (!nowayout) {
293			size_t i;
294
295			/* In case it was set long ago */
296			expect_close = 0;
297
298			for (i = 0; i != count; i++) {
299				char c;
300				if (get_user(c, buf + i))
301					return -EFAULT;
302				if (c == 'V')
303					expect_close = 42;
304			}
305		}
306		wdt_ping();
307	}
308	return count;
309}
310
311/**
312 *	wdt_ioctl:
313 *	@inode: inode of the device
314 *	@file: file handle to the device
315 *	@cmd: watchdog command
316 *	@arg: argument pointer
317 *
318 *	The watchdog API defines a common set of functions for all watchdogs
319 *	according to their available features. We only actually usefully support
320 *	querying capabilities and current status.
321 */
322
323static int wdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
324	unsigned long arg)
325{
326	void __user *argp = (void __user *)arg;
327	int __user *p = argp;
328	int new_heartbeat;
329	int status;
330
331	static struct watchdog_info ident = {
332		.options =		WDIOF_SETTIMEOUT|
333					WDIOF_MAGICCLOSE|
334					WDIOF_KEEPALIVEPING,
335		.firmware_version =	1,
336		.identity =		"WDT500/501",
337	};
338
339	/* Add options according to the card we have */
340	ident.options |= (WDIOF_EXTERN1|WDIOF_EXTERN2);
341#ifdef CONFIG_WDT_501
342	ident.options |= (WDIOF_OVERHEAT|WDIOF_POWERUNDER|WDIOF_POWEROVER);
343	if (tachometer)
344		ident.options |= WDIOF_FANFAULT;
345#endif /* CONFIG_WDT_501 */
346
347	switch(cmd)
348	{
349		default:
350			return -ENOIOCTLCMD;
351		case WDIOC_GETSUPPORT:
352			return copy_to_user(argp, &ident, sizeof(ident))?-EFAULT:0;
353
354		case WDIOC_GETSTATUS:
355			wdt_get_status(&status);
356			return put_user(status, p);
357		case WDIOC_GETBOOTSTATUS:
358			return put_user(0, p);
359		case WDIOC_KEEPALIVE:
360			wdt_ping();
361			return 0;
362		case WDIOC_SETTIMEOUT:
363			if (get_user(new_heartbeat, p))
364				return -EFAULT;
365
366			if (wdt_set_heartbeat(new_heartbeat))
367				return -EINVAL;
368
369			wdt_ping();
370			/* Fall */
371		case WDIOC_GETTIMEOUT:
372			return put_user(heartbeat, p);
373	}
374}
375
376/**
377 *	wdt_open:
378 *	@inode: inode of device
379 *	@file: file handle to device
380 *
381 *	The watchdog device has been opened. The watchdog device is single
382 *	open and on opening we load the counters. Counter zero is a 100Hz
383 *	cascade, into counter 1 which downcounts to reboot. When the counter
384 *	triggers counter 2 downcounts the length of the reset pulse which
385 *	set set to be as long as possible.
386 */
387
388static int wdt_open(struct inode *inode, struct file *file)
389{
390	if(test_and_set_bit(0, &wdt_is_open))
391		return -EBUSY;
392	/*
393	 *	Activate
394	 */
395	wdt_start();
396	return nonseekable_open(inode, file);
397}
398
399/**
400 *	wdt_release:
401 *	@inode: inode to board
402 *	@file: file handle to board
403 *
404 *	The watchdog has a configurable API. There is a religious dispute
405 *	between people who want their watchdog to be able to shut down and
406 *	those who want to be sure if the watchdog manager dies the machine
407 *	reboots. In the former case we disable the counters, in the latter
408 *	case you have to open it again very soon.
409 */
410
411static int wdt_release(struct inode *inode, struct file *file)
412{
413	if (expect_close == 42) {
414		wdt_stop();
415		clear_bit(0, &wdt_is_open);
416	} else {
417		printk(KERN_CRIT "wdt: WDT device closed unexpectedly.  WDT will not stop!\n");
418		wdt_ping();
419	}
420	expect_close = 0;
421	return 0;
422}
423
424#ifdef CONFIG_WDT_501
425/**
426 *	wdt_temp_read:
427 *	@file: file handle to the watchdog board
428 *	@buf: buffer to write 1 byte into
429 *	@count: length of buffer
430 *	@ptr: offset (no seek allowed)
431 *
432 *	Temp_read reports the temperature in degrees Fahrenheit. The API is in
433 *	farenheit. It was designed by an imperial measurement luddite.
434 */
435
436static ssize_t wdt_temp_read(struct file *file, char __user *buf, size_t count, loff_t *ptr)
437{
438	int temperature;
439
440	if (wdt_get_temperature(&temperature))
441		return -EFAULT;
442
443	if (copy_to_user (buf, &temperature, 1))
444		return -EFAULT;
445
446	return 1;
447}
448
449/**
450 *	wdt_temp_open:
451 *	@inode: inode of device
452 *	@file: file handle to device
453 *
454 *	The temperature device has been opened.
455 */
456
457static int wdt_temp_open(struct inode *inode, struct file *file)
458{
459	return nonseekable_open(inode, file);
460}
461
462/**
463 *	wdt_temp_release:
464 *	@inode: inode to board
465 *	@file: file handle to board
466 *
467 *	The temperature device has been closed.
468 */
469
470static int wdt_temp_release(struct inode *inode, struct file *file)
471{
472	return 0;
473}
474#endif /* CONFIG_WDT_501 */
475
476/**
477 *	notify_sys:
478 *	@this: our notifier block
479 *	@code: the event being reported
480 *	@unused: unused
481 *
482 *	Our notifier is called on system shutdowns. We want to turn the card
483 *	off at reboot otherwise the machine will reboot again during memory
484 *	test or worse yet during the following fsck. This would suck, in fact
485 *	trust me - if it happens it does suck.
486 */
487
488static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
489	void *unused)
490{
491	if(code==SYS_DOWN || code==SYS_HALT) {
492		/* Turn the card off */
493		wdt_stop();
494	}
495	return NOTIFY_DONE;
496}
497
498/*
499 *	Kernel Interfaces
500 */
501
502
503static struct file_operations wdt_fops = {
504	.owner		= THIS_MODULE,
505	.llseek		= no_llseek,
506	.write		= wdt_write,
507	.ioctl		= wdt_ioctl,
508	.open		= wdt_open,
509	.release	= wdt_release,
510};
511
512static struct miscdevice wdt_miscdev = {
513	.minor	= WATCHDOG_MINOR,
514	.name	= "watchdog",
515	.fops	= &wdt_fops,
516};
517
518#ifdef CONFIG_WDT_501
519static struct file_operations wdt_temp_fops = {
520	.owner		= THIS_MODULE,
521	.llseek		= no_llseek,
522	.read		= wdt_temp_read,
523	.open		= wdt_temp_open,
524	.release	= wdt_temp_release,
525};
526
527static struct miscdevice temp_miscdev = {
528	.minor	= TEMP_MINOR,
529	.name	= "temperature",
530	.fops	= &wdt_temp_fops,
531};
532#endif /* CONFIG_WDT_501 */
533
534/*
535 *	The WDT card needs to learn about soft shutdowns in order to
536 *	turn the timebomb registers off.
537 */
538
539static struct notifier_block wdt_notifier = {
540	.notifier_call = wdt_notify_sys,
541};
542
543/**
544 *	cleanup_module:
545 *
546 *	Unload the watchdog. You cannot do this with any file handles open.
547 *	If your watchdog is set to continue ticking on close and you unload
548 *	it, well it keeps ticking. We won't get the interrupt but the board
549 *	will not touch PC memory so all is fine. You just have to load a new
550 *	module in 60 seconds or reboot.
551 */
552
553static void __exit wdt_exit(void)
554{
555	misc_deregister(&wdt_miscdev);
556#ifdef CONFIG_WDT_501
557	misc_deregister(&temp_miscdev);
558#endif /* CONFIG_WDT_501 */
559	unregister_reboot_notifier(&wdt_notifier);
560	free_irq(irq, NULL);
561	release_region(io,8);
562}
563
564/**
565 * 	wdt_init:
566 *
567 *	Set up the WDT watchdog board. All we have to do is grab the
568 *	resources we require and bitch if anyone beat us to them.
569 *	The open() function will actually kick the board off.
570 */
571
572static int __init wdt_init(void)
573{
574	int ret;
575
576	/* Check that the heartbeat value is within it's range ; if not reset to the default */
577	if (wdt_set_heartbeat(heartbeat)) {
578		wdt_set_heartbeat(WD_TIMO);
579		printk(KERN_INFO "wdt: heartbeat value must be 0<heartbeat<65536, using %d\n",
580			WD_TIMO);
581	}
582
583	if (!request_region(io, 8, "wdt501p")) {
584		printk(KERN_ERR "wdt: I/O address 0x%04x already in use\n", io);
585		ret = -EBUSY;
586		goto out;
587	}
588
589	ret = request_irq(irq, wdt_interrupt, SA_INTERRUPT, "wdt501p", NULL);
590	if(ret) {
591		printk(KERN_ERR "wdt: IRQ %d is not free.\n", irq);
592		goto outreg;
593	}
594
595	ret = register_reboot_notifier(&wdt_notifier);
596	if(ret) {
597		printk(KERN_ERR "wdt: cannot register reboot notifier (err=%d)\n", ret);
598		goto outirq;
599	}
600
601#ifdef CONFIG_WDT_501
602	ret = misc_register(&temp_miscdev);
603	if (ret) {
604		printk(KERN_ERR "wdt: cannot register miscdev on minor=%d (err=%d)\n",
605			TEMP_MINOR, ret);
606		goto outrbt;
607	}
608#endif /* CONFIG_WDT_501 */
609
610	ret = misc_register(&wdt_miscdev);
611	if (ret) {
612		printk(KERN_ERR "wdt: cannot register miscdev on minor=%d (err=%d)\n",
613			WATCHDOG_MINOR, ret);
614		goto outmisc;
615	}
616
617	ret = 0;
618	printk(KERN_INFO "WDT500/501-P driver 0.10 at 0x%04x (Interrupt %d). heartbeat=%d sec (nowayout=%d)\n",
619		io, irq, heartbeat, nowayout);
620#ifdef CONFIG_WDT_501
621	printk(KERN_INFO "wdt: Fan Tachometer is %s\n", (tachometer ? "Enabled" : "Disabled"));
622#endif /* CONFIG_WDT_501 */
623
624out:
625	return ret;
626
627outmisc:
628#ifdef CONFIG_WDT_501
629	misc_deregister(&temp_miscdev);
630outrbt:
631#endif /* CONFIG_WDT_501 */
632	unregister_reboot_notifier(&wdt_notifier);
633outirq:
634	free_irq(irq, NULL);
635outreg:
636	release_region(io,8);
637	goto out;
638}
639
640module_init(wdt_init);
641module_exit(wdt_exit);
642
643MODULE_AUTHOR("Alan Cox");
644MODULE_DESCRIPTION("Driver for ISA ICS watchdog cards (WDT500/501)");
645MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
646MODULE_ALIAS_MISCDEV(TEMP_MINOR);
647MODULE_LICENSE("GPL");