drivers/watchdog/acquirewdt.c - kernel/skids - Git at Google

 /*
  *	Acquire Single Board Computer Watchdog Timer driver
  *
  *	Based on wdt.c. Original copyright messages:
  *
  *	(c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>,
  *						All Rights Reserved.
  *
  *	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 <alan@lxorguk.ukuu.org.uk>
  *
  *	14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com>
  *	    Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT
  *	    Can't add timeout - driver doesn't allow changing value
  */

 /*
  *	Theory of Operation:
  *		The Watch-Dog Timer is provided to ensure that standalone
  *		Systems can always recover from catastrophic conditions that
  *		caused the CPU to crash. This condition may have occured by
  *		external EMI or a software bug. When the CPU stops working
  *		correctly, hardware on the board will either perform a hardware
  *		reset (cold boot) or a non-maskable interrupt (NMI) to bring the
  *		system back to a known state.
  *
  *		The Watch-Dog Timer is controlled by two I/O Ports.
  *		  443 hex	- Read	- Enable or refresh the Watch-Dog Timer
  *		  043 hex	- Read	- Disable the Watch-Dog Timer
  *
  *		To enable the Watch-Dog Timer, a read from I/O port 443h must
  *		be performed. This will enable and activate the countdown timer
  *		which will eventually time out and either reset the CPU or cause
  *		an NMI depending on the setting of a jumper. To ensure that this
  *		reset condition does not occur, the Watch-Dog Timer must be
  *		periodically refreshed by reading the same I/O port 443h.
  *		The Watch-Dog Timer is disabled by reading I/O port 043h.
  *
  *		The Watch-Dog Timer Time-Out Period is set via jumpers.
  *		It can be 1, 2, 10, 20, 110 or 220 seconds.
  */

 /*
  *	Includes, defines, variables, module parameters, ...
  */

 /* Includes */
 #include <linux/module.h>		/* For module specific items */
 #include <linux/moduleparam.h>		/* For new moduleparam's */
 #include <linux/types.h>		/* For standard types (like size_t) */
 #include <linux/errno.h>		/* For the -ENODEV/... values */
 #include <linux/kernel.h>		/* For printk/panic/... */
 #include <linux/miscdevice.h>		/* For MODULE_ALIAS_MISCDEV
 							(WATCHDOG_MINOR) */
 #include <linux/watchdog.h>		/* For the watchdog specific items */
 #include <linux/fs.h>			/* For file operations */
 #include <linux/ioport.h>		/* For io-port access */
 #include <linux/platform_device.h>	/* For platform_driver framework */
 #include <linux/init.h>			/* For __init/__exit/... */
 #include <linux/uaccess.h>		/* For copy_to_user/put_user/... */
 #include <linux/io.h>			/* For inb/outb/... */

 /* Module information */
 #define DRV_NAME "acquirewdt"
 #define PFX DRV_NAME ": "
 #define WATCHDOG_NAME "Acquire WDT"
 /* There is no way to see what the correct time-out period is */
 #define WATCHDOG_HEARTBEAT 0

 /* internal variables */
 /* the watchdog platform device */
 static struct platform_device *acq_platform_device;
 static unsigned long acq_is_open;
 static char expect_close;

 /* module parameters */
 /* You must set this - there is no sane way to probe for this board. */
 static int wdt_stop = 0x43;
 module_param(wdt_stop, int, 0);
 MODULE_PARM_DESC(wdt_stop, "Acquire WDT 'stop' io port (default 0x43)");

 /* You must set this - there is no sane way to probe for this board. */
 static int wdt_start = 0x443;
 module_param(wdt_start, int, 0);
 MODULE_PARM_DESC(wdt_start, "Acquire WDT 'start' io port (default 0x443)");

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

 /*
  *	Watchdog Operations
  */

 static void acq_keepalive(void)
 {
 	/* Write a watchdog value */
 	inb_p(wdt_start);
 }

 static void acq_stop(void)
 {
 	/* Turn the card off */
 	inb_p(wdt_stop);
 }

 /*
  *	/dev/watchdog handling
  */

 static ssize_t acq_write(struct file *file, const char __user *buf,
 						size_t count, loff_t *ppos)
 {
 	/* See if we got the magic character 'V' and reload the timer */
 	if (count) {
 		if (!nowayout) {
 			size_t i;
 			/* note: just in case someone wrote the magic character
 			   five months ago... */
 			expect_close = 0;
 			/* scan to see whether or not we got the
 			   magic character */
 			for (i = 0; i != count; i++) {
 				char c;
 				if (get_user(c, buf + i))
 					return -EFAULT;
 				if (c == 'V')
 					expect_close = 42;
 			}
 		}
 		/* Well, anyhow someone wrote to us, we should
 				return that favour */
 		acq_keepalive();
 	}
 	return count;
 }

 static long acq_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 {
 	int options, retval = -EINVAL;
 	void __user *argp = (void __user *)arg;
 	int __user *p = argp;
 	static const struct watchdog_info ident = {
 		.options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
 		.firmware_version = 1,
 		.identity = WATCHDOG_NAME,
 	};

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

 	case WDIOC_GETSTATUS:
 	case WDIOC_GETBOOTSTATUS:
 		return put_user(0, p);

 	case WDIOC_SETOPTIONS:
 	{
 		if (get_user(options, p))
 			return -EFAULT;
 		if (options & WDIOS_DISABLECARD) {
 			acq_stop();
 			retval = 0;
 		}
 		if (options & WDIOS_ENABLECARD) {
 			acq_keepalive();
 			retval = 0;
 		}
 		return retval;
 	}
 	case WDIOC_KEEPALIVE:
 		acq_keepalive();
 		return 0;

 	case WDIOC_GETTIMEOUT:
 		return put_user(WATCHDOG_HEARTBEAT, p);

 	default:
 		return -ENOTTY;
 	}
 }

 static int acq_open(struct inode *inode, struct file *file)
 {
 	if (test_and_set_bit(0, &acq_is_open))
 		return -EBUSY;

 	if (nowayout)
 		__module_get(THIS_MODULE);

 	/* Activate */
 	acq_keepalive();
 	return nonseekable_open(inode, file);
 }

 static int acq_close(struct inode *inode, struct file *file)
 {
 	if (expect_close == 42) {
 		acq_stop();
 	} else {
 		printk(KERN_CRIT PFX
 			"Unexpected close, not stopping watchdog!\n");
 		acq_keepalive();
 	}
 	clear_bit(0, &acq_is_open);
 	expect_close = 0;
 	return 0;
 }

 /*
  *	Kernel Interfaces
  */

 static const struct file_operations acq_fops = {
 	.owner		= THIS_MODULE,
 	.llseek		= no_llseek,
 	.write		= acq_write,
 	.unlocked_ioctl	= acq_ioctl,
 	.open		= acq_open,
 	.release	= acq_close,
 };

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

 /*
  *	Init & exit routines
  */

 static int __devinit acq_probe(struct platform_device *dev)
 {
 	int ret;

 	if (wdt_stop != wdt_start) {
 		if (!request_region(wdt_stop, 1, WATCHDOG_NAME)) {
 			printk(KERN_ERR PFX
 			    "I/O address 0x%04x already in use\n", wdt_stop);
 			ret = -EIO;
 			goto out;
 		}
 	}

 	if (!request_region(wdt_start, 1, WATCHDOG_NAME)) {
 		printk(KERN_ERR PFX "I/O address 0x%04x already in use\n",
 			wdt_start);
 		ret = -EIO;
 		goto unreg_stop;
 	}
 	ret = misc_register(&acq_miscdev);
 	if (ret != 0) {
 		printk(KERN_ERR PFX
 			"cannot register miscdev on minor=%d (err=%d)\n",
 							WATCHDOG_MINOR, ret);
 		goto unreg_regions;
 	}
 	printk(KERN_INFO PFX "initialized. (nowayout=%d)\n", nowayout);

 	return 0;
 unreg_regions:
 	release_region(wdt_start, 1);
 unreg_stop:
 	if (wdt_stop != wdt_start)
 		release_region(wdt_stop, 1);
 out:
 	return ret;
 }

 static int __devexit acq_remove(struct platform_device *dev)
 {
 	misc_deregister(&acq_miscdev);
 	release_region(wdt_start, 1);
 	if (wdt_stop != wdt_start)
 		release_region(wdt_stop, 1);

 	return 0;
 }

 static void acq_shutdown(struct platform_device *dev)
 {
 	/* Turn the WDT off if we have a soft shutdown */
 	acq_stop();
 }

 static struct platform_driver acquirewdt_driver = {
 	.probe		= acq_probe,
 	.remove		= __devexit_p(acq_remove),
 	.shutdown	= acq_shutdown,
 	.driver		= {
 		.owner	= THIS_MODULE,
 		.name	= DRV_NAME,
 	},
 };

 static int __init acq_init(void)
 {
 	int err;

 	printk(KERN_INFO
 	      "WDT driver for Acquire single board computer initialising.\n");

 	err = platform_driver_register(&acquirewdt_driver);
 	if (err)
 		return err;

 	acq_platform_device = platform_device_register_simple(DRV_NAME,
 								-1, NULL, 0);
 	if (IS_ERR(acq_platform_device)) {
 		err = PTR_ERR(acq_platform_device);
 		goto unreg_platform_driver;
 	}
 	return 0;

 unreg_platform_driver:
 	platform_driver_unregister(&acquirewdt_driver);
 	return err;
 }

 static void __exit acq_exit(void)
 {
 	platform_device_unregister(acq_platform_device);
 	platform_driver_unregister(&acquirewdt_driver);
 	printk(KERN_INFO PFX "Watchdog Module Unloaded.\n");
 }

 module_init(acq_init);
 module_exit(acq_exit);

 MODULE_AUTHOR("David Woodhouse");
 MODULE_DESCRIPTION("Acquire Inc. Single Board Computer Watchdog Timer driver");
 MODULE_LICENSE("GPL");
 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
	/*
	* Acquire Single Board Computer Watchdog Timer driver
	*
	* Based on wdt.c. Original copyright messages:
	*
	* (c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>,
	* All Rights Reserved.
	*
	* 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 <alan@lxorguk.ukuu.org.uk>
	*
	* 14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com>
	* Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT
	* Can't add timeout - driver doesn't allow changing value
	*/

	/*
	* Theory of Operation:
	* The Watch-Dog Timer is provided to ensure that standalone
	* Systems can always recover from catastrophic conditions that
	* caused the CPU to crash. This condition may have occured by
	* external EMI or a software bug. When the CPU stops working
	* correctly, hardware on the board will either perform a hardware
	* reset (cold boot) or a non-maskable interrupt (NMI) to bring the
	* system back to a known state.
	*
	* The Watch-Dog Timer is controlled by two I/O Ports.
	* 443 hex - Read - Enable or refresh the Watch-Dog Timer
	* 043 hex - Read - Disable the Watch-Dog Timer
	*
	* To enable the Watch-Dog Timer, a read from I/O port 443h must
	* be performed. This will enable and activate the countdown timer
	* which will eventually time out and either reset the CPU or cause
	* an NMI depending on the setting of a jumper. To ensure that this
	* reset condition does not occur, the Watch-Dog Timer must be
	* periodically refreshed by reading the same I/O port 443h.
	* The Watch-Dog Timer is disabled by reading I/O port 043h.
	*
	* The Watch-Dog Timer Time-Out Period is set via jumpers.
	* It can be 1, 2, 10, 20, 110 or 220 seconds.
	*/

	/*
	* Includes, defines, variables, module parameters, ...
	*/

	/* Includes */
	#include <linux/module.h> /* For module specific items */
	#include <linux/moduleparam.h> /* For new moduleparam's */
	#include <linux/types.h> /* For standard types (like size_t) */
	#include <linux/errno.h> /* For the -ENODEV/... values */
	#include <linux/kernel.h> /* For printk/panic/... */
	#include <linux/miscdevice.h> /* For MODULE_ALIAS_MISCDEV
	(WATCHDOG_MINOR) */
	#include <linux/watchdog.h> /* For the watchdog specific items */
	#include <linux/fs.h> /* For file operations */
	#include <linux/ioport.h> /* For io-port access */
	#include <linux/platform_device.h> /* For platform_driver framework */
	#include <linux/init.h> /* For __init/__exit/... */
	#include <linux/uaccess.h> /* For copy_to_user/put_user/... */
	#include <linux/io.h> /* For inb/outb/... */

	/* Module information */
	#define DRV_NAME "acquirewdt"
	#define PFX DRV_NAME ": "
	#define WATCHDOG_NAME "Acquire WDT"
	/* There is no way to see what the correct time-out period is */
	#define WATCHDOG_HEARTBEAT 0

	/* internal variables */
	/* the watchdog platform device */
	static struct platform_device *acq_platform_device;
	static unsigned long acq_is_open;
	static char expect_close;

	/* module parameters */
	/* You must set this - there is no sane way to probe for this board. */
	static int wdt_stop = 0x43;
	module_param(wdt_stop, int, 0);
	MODULE_PARM_DESC(wdt_stop, "Acquire WDT 'stop' io port (default 0x43)");

	/* You must set this - there is no sane way to probe for this board. */
	static int wdt_start = 0x443;
	module_param(wdt_start, int, 0);
	MODULE_PARM_DESC(wdt_start, "Acquire WDT 'start' io port (default 0x443)");

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

	/*
	* Watchdog Operations
	*/

	static void acq_keepalive(void)
	{
	/* Write a watchdog value */
	inb_p(wdt_start);
	}

	static void acq_stop(void)
	{
	/* Turn the card off */
	inb_p(wdt_stop);
	}

	/*
	* /dev/watchdog handling
	*/

	static ssize_t acq_write(struct file file, const char __user buf,
	size_t count, loff_t *ppos)
	{
	/* See if we got the magic character 'V' and reload the timer */
	if (count) {
	if (!nowayout) {
	size_t i;
	/* note: just in case someone wrote the magic character
	five months ago... */
	expect_close = 0;
	/* scan to see whether or not we got the
	magic character */
	for (i = 0; i != count; i++) {
	char c;
	if (get_user(c, buf + i))
	return -EFAULT;
	if (c == 'V')
	expect_close = 42;
	}
	}
	/* Well, anyhow someone wrote to us, we should
	return that favour */
	acq_keepalive();
	}
	return count;
	}

	static long acq_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
	{
	int options, retval = -EINVAL;
	void __user argp = (void __user )arg;
	int __user *p = argp;
	static const struct watchdog_info ident = {
	.options = WDIOF_KEEPALIVEPING \| WDIOF_MAGICCLOSE,
	.firmware_version = 1,
	.identity = WATCHDOG_NAME,
	};

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

	case WDIOC_GETSTATUS:
	case WDIOC_GETBOOTSTATUS:
	return put_user(0, p);

	case WDIOC_SETOPTIONS:
	{
	if (get_user(options, p))
	return -EFAULT;
	if (options & WDIOS_DISABLECARD) {
	acq_stop();
	retval = 0;
	}
	if (options & WDIOS_ENABLECARD) {
	acq_keepalive();
	retval = 0;
	}
	return retval;
	}
	case WDIOC_KEEPALIVE:
	acq_keepalive();
	return 0;

	case WDIOC_GETTIMEOUT:
	return put_user(WATCHDOG_HEARTBEAT, p);

	default:
	return -ENOTTY;
	}
	}

	static int acq_open(struct inode inode, struct file file)
	{
	if (test_and_set_bit(0, &acq_is_open))
	return -EBUSY;

	if (nowayout)
	__module_get(THIS_MODULE);

	/* Activate */
	acq_keepalive();
	return nonseekable_open(inode, file);
	}

	static int acq_close(struct inode inode, struct file file)
	{
	if (expect_close == 42) {
	acq_stop();
	} else {
	printk(KERN_CRIT PFX
	"Unexpected close, not stopping watchdog!\n");
	acq_keepalive();
	}
	clear_bit(0, &acq_is_open);
	expect_close = 0;
	return 0;
	}

	/*
	* Kernel Interfaces
	*/

	static const struct file_operations acq_fops = {
	.owner = THIS_MODULE,
	.llseek = no_llseek,
	.write = acq_write,
	.unlocked_ioctl = acq_ioctl,
	.open = acq_open,
	.release = acq_close,
	};

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

	/*
	* Init & exit routines
	*/

	static int __devinit acq_probe(struct platform_device *dev)
	{
	int ret;

	if (wdt_stop != wdt_start) {
	if (!request_region(wdt_stop, 1, WATCHDOG_NAME)) {
	printk(KERN_ERR PFX
	"I/O address 0x%04x already in use\n", wdt_stop);
	ret = -EIO;
	goto out;
	}
	}

	if (!request_region(wdt_start, 1, WATCHDOG_NAME)) {
	printk(KERN_ERR PFX "I/O address 0x%04x already in use\n",
	wdt_start);
	ret = -EIO;
	goto unreg_stop;
	}
	ret = misc_register(&acq_miscdev);
	if (ret != 0) {
	printk(KERN_ERR PFX
	"cannot register miscdev on minor=%d (err=%d)\n",
	WATCHDOG_MINOR, ret);
	goto unreg_regions;
	}
	printk(KERN_INFO PFX "initialized. (nowayout=%d)\n", nowayout);

	return 0;
	unreg_regions:
	release_region(wdt_start, 1);
	unreg_stop:
	if (wdt_stop != wdt_start)
	release_region(wdt_stop, 1);
	out:
	return ret;
	}

	static int __devexit acq_remove(struct platform_device *dev)
	{
	misc_deregister(&acq_miscdev);
	release_region(wdt_start, 1);
	if (wdt_stop != wdt_start)
	release_region(wdt_stop, 1);

	return 0;
	}

	static void acq_shutdown(struct platform_device *dev)
	{
	/* Turn the WDT off if we have a soft shutdown */
	acq_stop();
	}

	static struct platform_driver acquirewdt_driver = {
	.probe = acq_probe,
	.remove = __devexit_p(acq_remove),
	.shutdown = acq_shutdown,
	.driver = {
	.owner = THIS_MODULE,
	.name = DRV_NAME,
	},
	};

	static int __init acq_init(void)
	{
	int err;

	printk(KERN_INFO
	"WDT driver for Acquire single board computer initialising.\n");

	err = platform_driver_register(&acquirewdt_driver);
	if (err)
	return err;

	acq_platform_device = platform_device_register_simple(DRV_NAME,
	-1, NULL, 0);
	if (IS_ERR(acq_platform_device)) {
	err = PTR_ERR(acq_platform_device);
	goto unreg_platform_driver;
	}
	return 0;

	unreg_platform_driver:
	platform_driver_unregister(&acquirewdt_driver);
	return err;
	}

	static void __exit acq_exit(void)
	{
	platform_device_unregister(acq_platform_device);
	platform_driver_unregister(&acquirewdt_driver);
	printk(KERN_INFO PFX "Watchdog Module Unloaded.\n");
	}

	module_init(acq_init);
	module_exit(acq_exit);

	MODULE_AUTHOR("David Woodhouse");
	MODULE_DESCRIPTION("Acquire Inc. Single Board Computer Watchdog Timer driver");
	MODULE_LICENSE("GPL");
	MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);