pc87413_wdt.c

来自「linux 内核源代码」· C语言 代码 · 共 634 行 · 第 1/2 页

	                         " %d minute(s).\n", timeout);

	return nonseekable_open(inode, file);
}

/**
 *	pc87413_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 pc87413_release(struct inode *inode, struct file *file)
{
	/* Shut off the timer. */

	if (expect_close == 42) {
		pc87413_disable();
		printk(KERN_INFO MODNAME "Watchdog disabled,"
		                         " sleeping again...\n");
	} else {
		printk(KERN_CRIT MODNAME "Unexpected close, not stopping"
		                         " watchdog!\n");
		pc87413_refresh();
	}

	clear_bit(0, &timer_enabled);
	expect_close = 0;

	return 0;
}

/**
 *	pc87413_status:
 *
 *      return, if the watchdog is enabled (timeout is set...)
 */


static int pc87413_status(void)
{
	  return 0; /* currently not supported */
}

/**
 *	pc87413_write:
 *	@file: file handle to the watchdog
 *	@data: data buffer to write
 *	@len: length in 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 pc87413_write(struct file *file, const char __user *data,
			     size_t len, loff_t *ppos)
{
	/* See if we got the magic character 'V' and reload the timer */
	if (len) {
		if (!nowayout) {
			size_t i;

			/* reset expect flag */
			expect_close = 0;

			/* scan to see whether or not we got the magic character */
			for (i = 0; i != len; i++) {
				char c;
				if (get_user(c, data+i))
					return -EFAULT;
				if (c == 'V')
					expect_close = 42;
			}
		}

		/* someone wrote to us, we should reload the timer */
		pc87413_refresh();
	}
	return len;
}

/**
 *	pc87413_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 pc87413_ioctl(struct inode *inode, struct file *file,
			 unsigned int cmd, unsigned long arg)
{
	int new_timeout;

	union {
		struct watchdog_info __user *ident;
		int __user *i;
	} uarg;

	static struct watchdog_info ident = {
		.options          = WDIOF_KEEPALIVEPING |
		                    WDIOF_SETTIMEOUT |
		                    WDIOF_MAGICCLOSE,
		.firmware_version = 1,
		.identity         = "PC87413(HF/F) watchdog"
	};

	uarg.i = (int __user *)arg;

	switch(cmd) {
		default:
			return -ENOTTY;

		case WDIOC_GETSUPPORT:
			return copy_to_user(uarg.ident, &ident,
				sizeof(ident)) ? -EFAULT : 0;

		case WDIOC_GETSTATUS:
			return put_user(pc87413_status(), uarg.i);

		case WDIOC_GETBOOTSTATUS:
			return put_user(0, uarg.i);

		case WDIOC_KEEPALIVE:
			pc87413_refresh();
#ifdef DEBUG
	                printk(KERN_INFO DPFX "keepalive\n");
#endif
			return 0;

		case WDIOC_SETTIMEOUT:
			if (get_user(new_timeout, uarg.i))
				return -EFAULT;

			// the API states this is given in secs
			new_timeout /= 60;

			if (new_timeout < 0 || new_timeout > MAX_TIMEOUT)
				return -EINVAL;

			timeout = new_timeout;
			pc87413_refresh();

			// fall through and return the new timeout...

		case WDIOC_GETTIMEOUT:

		        new_timeout = timeout * 60;

			return put_user(new_timeout, uarg.i);

		case WDIOC_SETOPTIONS:
		{
			int options, retval = -EINVAL;

			if (get_user(options, uarg.i))
				return -EFAULT;

			if (options & WDIOS_DISABLECARD) {
			        pc87413_disable();
				retval = 0;
			}

			if (options & WDIOS_ENABLECARD) {
				pc87413_enable();
				retval = 0;
			}

			return retval;
		}
	}
}

/* -- Notifier funtions -----------------------------------------*/

/**
 *	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 pc87413_notify_sys(struct notifier_block *this,
			      unsigned long code,
			      void *unused)
{
	if (code == SYS_DOWN || code == SYS_HALT)
	{
		/* Turn the card off */
		pc87413_disable();
	}
	return NOTIFY_DONE;
}

/* -- Module's structures ---------------------------------------*/

static const struct file_operations pc87413_fops = {
	.owner		= THIS_MODULE,
	.llseek		= no_llseek,
	.write		= pc87413_write,
	.ioctl		= pc87413_ioctl,
	.open		= pc87413_open,
	.release	= pc87413_release,
};

static struct notifier_block pc87413_notifier =
{
	.notifier_call  = pc87413_notify_sys,
};

static struct miscdevice pc87413_miscdev=
{
	.minor          = WATCHDOG_MINOR,
	.name           = "watchdog",
	.fops           = &pc87413_fops
};

/* -- Module init functions -------------------------------------*/

/**
 * 	pc87413_init: module's "constructor"
 *
 *	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 pc87413_init(void)
{
	int ret;

	printk(KERN_INFO PFX "Version " VERSION " at io 0x%X\n", WDT_INDEX_IO_PORT);

	/* request_region(io, 2, "pc87413"); */

	ret = register_reboot_notifier(&pc87413_notifier);
	if (ret != 0) {
		printk(KERN_ERR PFX "cannot register reboot notifier (err=%d)\n",
			ret);
	}

	ret = misc_register(&pc87413_miscdev);

	if (ret != 0) {
		printk(KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n",
			WATCHDOG_MINOR, ret);
		unregister_reboot_notifier(&pc87413_notifier);
		return ret;
	}

	printk(KERN_INFO PFX "initialized. timeout=%d min \n", timeout);

	pc87413_enable();

	return 0;
}

/**
 *	pc87413_exit: module's "destructor"
 *
 *	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 pc87413_exit(void)
{
	/* Stop the timer before we leave */
	if (!nowayout)
	{
		pc87413_disable();
		printk(KERN_INFO MODNAME "Watchdog disabled.\n");
	}

	misc_deregister(&pc87413_miscdev);
	unregister_reboot_notifier(&pc87413_notifier);
	/* release_region(io,2); */

	printk(MODNAME " watchdog component driver removed.\n");
}

module_init(pc87413_init);
module_exit(pc87413_exit);

MODULE_AUTHOR("Sven Anders <[e-mail]>, Marcus Junker <[e-mail]>,");
MODULE_DESCRIPTION("PC87413 WDT driver");
MODULE_LICENSE("GPL");

MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);

module_param(io, int, 0);
MODULE_PARM_DESC(io, MODNAME " I/O port (default: " __MODULE_STRING(io) ").");

module_param(timeout, int, 0);
MODULE_PARM_DESC(timeout, "Watchdog timeout in minutes (default=" __MODULE_STRING(timeout) ").");

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