smsc37b787_wdt.c

来自「linux 内核源代码」· C语言 代码 · 共 626 行 · 第 1/2 页

        wb_smsc_wdt_set_timeout(timeout);
}

/* reset the timer */

static void wb_smsc_wdt_reset_timer(void)
{
	spin_lock(&io_lock);
        open_io_config();
        select_io_device(IODEV_NO);

	// reset the timer
	wdt_timeout_value(timeout);
	wdt_timer_conf(0x08);

        close_io_config();
	spin_unlock(&io_lock);
}

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

static int wb_smsc_wdt_status(void)
{
	return (wb_smsc_wdt_get_timeout() == 0) ? 0 : WDIOF_KEEPALIVEPING;
}


/* -- File operations -------------------------------------------*/

/* open => enable watchdog and set initial timeout */

static int wb_smsc_wdt_open(struct inode *inode, struct file *file)
{
	/* /dev/watchdog can only be opened once */

	if (test_and_set_bit(0, &timer_enabled))
		return -EBUSY;

	if (nowayout)
		__module_get(THIS_MODULE);

	/* Reload and activate timer */
	wb_smsc_wdt_enable();

	printk(KERN_INFO MODNAME "Watchdog enabled. Timeout set to %d %s.\n", timeout, (unit == UNIT_SECOND) ? "second(s)" : "minute(s)");

	return nonseekable_open(inode, file);
}

/* close => shut off the timer */

static int wb_smsc_wdt_release(struct inode *inode, struct file *file)
{
	/* Shut off the timer. */

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

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

/* write => update the timer to keep the machine alive */

static ssize_t wb_smsc_wdt_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 */
		wb_smsc_wdt_reset_timer();
	}
	return len;
}

/* ioctl => control interface */

static int wb_smsc_wdt_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 =	0,
		.identity = 		"SMsC 37B787 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(wb_smsc_wdt_status(), uarg.i);

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

		case WDIOC_KEEPALIVE:
			wb_smsc_wdt_reset_timer();
			return 0;

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

			// the API states this is given in secs
			if (unit == UNIT_MINUTE)
			  new_timeout /= 60;

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

			timeout = new_timeout;
			wb_smsc_wdt_set_timeout(timeout);

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

		case WDIOC_GETTIMEOUT:

		        new_timeout = timeout;

			if (unit == UNIT_MINUTE)
			  new_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) {
				wb_smsc_wdt_disable();
				retval = 0;
			}

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

			return retval;
		}
	}
}

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

static int wb_smsc_wdt_notify_sys(struct notifier_block *this, unsigned long code, void *unused)
{
	if (code == SYS_DOWN || code == SYS_HALT)
	{
                // set timeout to 0, to avoid possible race-condition
	        timeout = 0;
		wb_smsc_wdt_disable();
	}
	return NOTIFY_DONE;
}

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

static const struct file_operations wb_smsc_wdt_fops =
{
	.owner          = THIS_MODULE,
	.llseek		= no_llseek,
	.write		= wb_smsc_wdt_write,
	.ioctl		= wb_smsc_wdt_ioctl,
	.open		= wb_smsc_wdt_open,
	.release	= wb_smsc_wdt_release,
};

static struct notifier_block wb_smsc_wdt_notifier =
{
	.notifier_call  = wb_smsc_wdt_notify_sys,
};

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

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

/* module's "constructor" */

static int __init wb_smsc_wdt_init(void)
{
	int ret;

	printk("SMsC 37B787 watchdog component driver " VERSION " initialising...\n");

	if (!request_region(IOPORT, IOPORT_SIZE, "SMsC 37B787 watchdog")) {
		printk(KERN_ERR MODNAME "Unable to register IO port %#x\n", IOPORT);
		ret = -EBUSY;
		goto out_pnp;
	}

        // set new maximum, if it's too big
        if (timeout > MAX_TIMEOUT)
               timeout = MAX_TIMEOUT;

        // init the watchdog timer
        wb_smsc_wdt_initialize();

	ret = register_reboot_notifier(&wb_smsc_wdt_notifier);
	if (ret) {
		printk(KERN_ERR MODNAME "Unable to register reboot notifier err = %d\n", ret);
		goto out_io;
	}

	ret = misc_register(&wb_smsc_wdt_miscdev);
	if (ret) {
		printk(KERN_ERR MODNAME "Unable to register miscdev on minor %d\n", WATCHDOG_MINOR);
		goto out_rbt;
	}

	// output info
	printk(KERN_INFO MODNAME "Timeout set to %d %s.\n", timeout, (unit == UNIT_SECOND) ? "second(s)" : "minute(s)");
	printk(KERN_INFO MODNAME "Watchdog initialized and sleeping (nowayout=%d)...\n", nowayout);

	// ret = 0

out_clean:
	return ret;

out_rbt:
	unregister_reboot_notifier(&wb_smsc_wdt_notifier);

out_io:
	release_region(IOPORT, IOPORT_SIZE);

out_pnp:
	goto out_clean;
}

/* module's "destructor" */

static void __exit wb_smsc_wdt_exit(void)
{
	/* Stop the timer before we leave */
	if (!nowayout)
	{
		wb_smsc_wdt_shutdown();
		printk(KERN_INFO MODNAME "Watchdog disabled.\n");
	}

	misc_deregister(&wb_smsc_wdt_miscdev);
	unregister_reboot_notifier(&wb_smsc_wdt_notifier);
	release_region(IOPORT, IOPORT_SIZE);

	printk("SMsC 37B787 watchdog component driver removed.\n");
}

module_init(wb_smsc_wdt_init);
module_exit(wb_smsc_wdt_exit);

MODULE_AUTHOR("Sven Anders <[e-mail]>");
MODULE_DESCRIPTION("Driver for SMsC 37B787 watchdog component (Version " VERSION ")");
MODULE_LICENSE("GPL");

MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);

#ifdef SMSC_SUPPORT_MINUTES
module_param(unit, int, 0);
MODULE_PARM_DESC(unit, "set unit to use, 0=seconds or 1=minutes, default is 0");
#endif

module_param(timeout, int, 0);
MODULE_PARM_DESC(timeout, "range is 1-255 units, default is 60");

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