wdt.c

linux2.6.13下2440看门狗驱动

/*
 *	Industrial Computer Source WDT500/501 driver
 *
 *	(c) Copyright 1996-1997 Alan Cox <[e-mail]>, 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 <[e-mail]>
 *
 *	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
 */

#include <linux/config.h>
#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 <asm/io.h>
#include <asm/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 int nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, int, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)");

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

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)");

#ifdef CONFIG_WDT_501
/* 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)");
#endif /* CONFIG_WDT_501 */

/*
 *	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)
{
	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 */
	return 0;
}

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

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

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

static int wdt_ping(void)
{
	/* 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 */
	return 0;
}

/**
 *	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 successfull 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:
 *	@status:		the new 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(int *status)
{
	unsigned char new_status=inb_p(WDT_SR);

	*status=0;
	if (new_status & WDC_SR_ISOI0)
		*status |= WDIOF_EXTERN1;
	if (new_status & WDC_SR_ISII1)
		*status |= WDIOF_EXTERN2;
#ifdef CONFIG_WDT_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;
	}
#endif /* CONFIG_WDT_501 */
	return 0;
}

#ifdef CONFIG_WDT_501
/**
 *	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(int *temperature)
{
	unsigned short c=inb_p(WDT_RT);

	*temperature = (c * 11 / 15) + 7;
	return 0;
}
#endif /* CONFIG_WDT_501 */

/**
 *	wdt_interrupt:
 *	@irq:		Interrupt number
 *	@dev_id:	Unused as we don't allow multiple devices.
 *	@regs:		Unused.
 *
 *	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, struct pt_regs *regs)
{
	/*
	 *	Read the status register see what is up and
	 *	then printk it.
	 */
	unsigned char status=inb_p(WDT_SR);

	printk(KERN_CRIT "WDT status %d\n", status);

#ifdef CONFIG_WDT_501
	if (!(status & WDC_SR_TGOOD))
		printk(KERN_CRIT "Overheat alarm.(%d)\n",inb_p(WDT_RT));
	if (!(status & WDC_SR_PSUOVER))
		printk(KERN_CRIT "PSU over voltage.\n");
	if (!(status & WDC_SR_PSUUNDR))
		printk(KERN_CRIT "PSU under voltage.\n");
	if (tachometer) {
		if (!(status & WDC_SR_FANGOOD))
			printk(KERN_CRIT "Possible fan fault.\n");
	}
#endif /* CONFIG_WDT_501 */
	if (!(status & WDC_SR_WCCR))
#ifdef SOFTWARE_REBOOT
#ifdef ONLY_TESTING
		printk(KERN_CRIT "Would Reboot.\n");
#else
		printk(KERN_CRIT "Initiating system reboot.\n");
		emergency_restart();
#endif
#else
		printk(KERN_CRIT "Reset in 5ms.\n");
#endif
	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:
 *	@inode: inode of the device
 *	@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 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;