wdt.c

linux2.6.13下2440看门狗驱动

	int new_heartbeat;
	int status;

	static 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);
#ifdef CONFIG_WDT_501
	ident.options |= (WDIOF_OVERHEAT|WDIOF_POWERUNDER|WDIOF_POWEROVER);
	if (tachometer)
		ident.options |= WDIOF_FANFAULT;
#endif /* CONFIG_WDT_501 */

	switch(cmd)
	{
		default:
			return -ENOIOCTLCMD;
		case WDIOC_GETSUPPORT:
			return copy_to_user(argp, &ident, sizeof(ident))?-EFAULT:0;

		case WDIOC_GETSTATUS:
			wdt_get_status(&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);
	}
}

/**
 *	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 {
		printk(KERN_CRIT "wdt: WDT device closed unexpectedly.  WDT will not stop!\n");
		wdt_ping();
	}
	expect_close = 0;
	return 0;
}

#ifdef CONFIG_WDT_501
/**
 *	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;

	if (wdt_get_temperature(&temperature))
		return -EFAULT;

	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;
}
#endif /* CONFIG_WDT_501 */

/**
 *	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) {
		/* Turn the card off */
		wdt_stop();
	}
	return NOTIFY_DONE;
}

/*
 *	Kernel Interfaces
 */


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

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

#ifdef CONFIG_WDT_501
static 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,
};
#endif /* CONFIG_WDT_501 */

/*
 *	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);
#ifdef CONFIG_WDT_501
	misc_deregister(&temp_miscdev);
#endif /* CONFIG_WDT_501 */
	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;

	/* 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);
		printk(KERN_INFO "wdt: heartbeat value must be 0<heartbeat<65536, using %d\n",
			WD_TIMO);
	}

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

	ret = request_irq(irq, wdt_interrupt, SA_INTERRUPT, "wdt501p", NULL);
	if(ret) {
		printk(KERN_ERR "wdt: IRQ %d is not free.\n", irq);
		goto outreg;
	}

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

#ifdef CONFIG_WDT_501
	ret = misc_register(&temp_miscdev);
	if (ret) {
		printk(KERN_ERR "wdt: cannot register miscdev on minor=%d (err=%d)\n",
			TEMP_MINOR, ret);
		goto outrbt;
	}
#endif /* CONFIG_WDT_501 */

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

	ret = 0;
	printk(KERN_INFO "WDT500/501-P driver 0.10 at 0x%04x (Interrupt %d). heartbeat=%d sec (nowayout=%d)\n",
		io, irq, heartbeat, nowayout);
#ifdef CONFIG_WDT_501
	printk(KERN_INFO "wdt: Fan Tachometer is %s\n", (tachometer ? "Enabled" : "Disabled"));
#endif /* CONFIG_WDT_501 */

out:
	return ret;

outmisc:
#ifdef CONFIG_WDT_501
	misc_deregister(&temp_miscdev);
outrbt:
#endif /* CONFIG_WDT_501 */
	unregister_reboot_notifier(&wdt_notifier);
outirq:
	free_irq(irq, NULL);
outreg:
	release_region(io,8);
	goto out;
}

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");