drivers/watchdog/wafer5823wdt.c - arm/linux-arm64-legacy - Git at Google

 /*
  *	ICP Wafer 5823 Single Board Computer WDT driver
  *	http://www.icpamerica.com/wafer_5823.php
  *	May also work on other similar models
  *
  *	(c) Copyright 2002 Justin Cormack <justin@street-vision.com>
  *
  *	Release 0.02
  *
  *	Based on advantechwdt.c which is based on wdt.c.
  *	Original copyright messages:
  *
  *	(c) Copyright 1996-1997 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>
  *
  */

 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

 #include <linux/module.h>
 #include <linux/moduleparam.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 <linux/spinlock.h>
 #include <linux/io.h>
 #include <linux/uaccess.h>

 #define WATCHDOG_NAME "Wafer 5823 WDT"
 #define PFX WATCHDOG_NAME ": "
 #define WD_TIMO 60			/* 60 sec default timeout */

 static unsigned long wafwdt_is_open;
 static char expect_close;
 static DEFINE_SPINLOCK(wafwdt_lock);

 /*
  *	You must set these - there is no sane way to probe for this board.
  *
  *	To enable, write the timeout value in seconds (1 to 255) to I/O
  *	port WDT_START, then read the port to start the watchdog. To pat
  *	the dog, read port WDT_STOP to stop the timer, then read WDT_START
  *	to restart it again.
  */

 static int wdt_stop = 0x843;
 static int wdt_start = 0x443;

 static int timeout = WD_TIMO;  /* in seconds */
 module_param(timeout, int, 0);
 MODULE_PARM_DESC(timeout,
 		"Watchdog timeout in seconds. 1 <= timeout <= 255, default="
 				__MODULE_STRING(WD_TIMO) ".");

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

 static void wafwdt_ping(void)
 {
 	/* pat watchdog */
 	spin_lock(&wafwdt_lock);
 	inb_p(wdt_stop);
 	inb_p(wdt_start);
 	spin_unlock(&wafwdt_lock);
 }

 static void wafwdt_start(void)
 {
 	/* start up watchdog */
 	outb_p(timeout, wdt_start);
 	inb_p(wdt_start);
 }

 static void wafwdt_stop(void)
 {
 	/* stop watchdog */
 	inb_p(wdt_stop);
 }

 static ssize_t wafwdt_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;

 			/* In case it was set long 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 */
 		wafwdt_ping();
 	}
 	return count;
 }

 static long wafwdt_ioctl(struct file *file, unsigned int cmd,
 							unsigned long arg)
 {
 	int new_timeout;
 	void __user *argp = (void __user *)arg;
 	int __user *p = argp;
 	static const struct watchdog_info ident = {
 		.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT |
 							WDIOF_MAGICCLOSE,
 		.firmware_version = 1,
 		.identity = "Wafer 5823 WDT",
 	};

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

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

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

 		if (get_user(options, p))
 			return -EFAULT;

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

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

 		return retval;
 	}

 	case WDIOC_KEEPALIVE:
 		wafwdt_ping();
 		break;

 	case WDIOC_SETTIMEOUT:
 		if (get_user(new_timeout, p))
 			return -EFAULT;
 		if ((new_timeout < 1) || (new_timeout > 255))
 			return -EINVAL;
 		timeout = new_timeout;
 		wafwdt_stop();
 		wafwdt_start();
 		/* Fall */
 	case WDIOC_GETTIMEOUT:
 		return put_user(timeout, p);

 	default:
 		return -ENOTTY;
 	}
 	return 0;
 }

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

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

 static int wafwdt_close(struct inode *inode, struct file *file)
 {
 	if (expect_close == 42)
 		wafwdt_stop();
 	else {
 		pr_crit("WDT device closed unexpectedly.  WDT will not stop!\n");
 		wafwdt_ping();
 	}
 	clear_bit(0, &wafwdt_is_open);
 	expect_close = 0;
 	return 0;
 }

 /*
  *	Notifier for system down
  */

 static int wafwdt_notify_sys(struct notifier_block *this, unsigned long code,
 								void *unused)
 {
 	if (code == SYS_DOWN || code == SYS_HALT)
 		wafwdt_stop();
 	return NOTIFY_DONE;
 }

 /*
  *	Kernel Interfaces
  */

 static const struct file_operations wafwdt_fops = {
 	.owner		= THIS_MODULE,
 	.llseek		= no_llseek,
 	.write		= wafwdt_write,
 	.unlocked_ioctl	= wafwdt_ioctl,
 	.open		= wafwdt_open,
 	.release	= wafwdt_close,
 };

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

 /*
  *	The WDT needs to learn about soft shutdowns in order to
  *	turn the timebomb registers off.
  */

 static struct notifier_block wafwdt_notifier = {
 	.notifier_call = wafwdt_notify_sys,
 };

 static int __init wafwdt_init(void)
 {
 	int ret;

 	pr_info("WDT driver for Wafer 5823 single board computer initialising\n");

 	if (timeout < 1 || timeout > 255) {
 		timeout = WD_TIMO;
 		pr_info("timeout value must be 1 <= x <= 255, using %d\n",
 			timeout);
 	}

 	if (wdt_stop != wdt_start) {
 		if (!request_region(wdt_stop, 1, "Wafer 5823 WDT")) {
 			pr_err("I/O address 0x%04x already in use\n", wdt_stop);
 			ret = -EIO;
 			goto error;
 		}
 	}

 	if (!request_region(wdt_start, 1, "Wafer 5823 WDT")) {
 		pr_err("I/O address 0x%04x already in use\n", wdt_start);
 		ret = -EIO;
 		goto error2;
 	}

 	ret = register_reboot_notifier(&wafwdt_notifier);
 	if (ret != 0) {
 		pr_err("cannot register reboot notifier (err=%d)\n", ret);
 		goto error3;
 	}

 	ret = misc_register(&wafwdt_miscdev);
 	if (ret != 0) {
 		pr_err("cannot register miscdev on minor=%d (err=%d)\n",
 		       WATCHDOG_MINOR, ret);
 		goto error4;
 	}

 	pr_info("initialized. timeout=%d sec (nowayout=%d)\n",
 		timeout, nowayout);

 	return ret;
 error4:
 	unregister_reboot_notifier(&wafwdt_notifier);
 error3:
 	release_region(wdt_start, 1);
 error2:
 	if (wdt_stop != wdt_start)
 		release_region(wdt_stop, 1);
 error:
 	return ret;
 }

 static void __exit wafwdt_exit(void)
 {
 	misc_deregister(&wafwdt_miscdev);
 	unregister_reboot_notifier(&wafwdt_notifier);
 	if (wdt_stop != wdt_start)
 		release_region(wdt_stop, 1);
 	release_region(wdt_start, 1);
 }

 module_init(wafwdt_init);
 module_exit(wafwdt_exit);

 MODULE_AUTHOR("Justin Cormack");
 MODULE_DESCRIPTION("ICP Wafer 5823 Single Board Computer WDT driver");
 MODULE_LICENSE("GPL");

 /* end of wafer5823wdt.c */
	/*
	* ICP Wafer 5823 Single Board Computer WDT driver
	* http://www.icpamerica.com/wafer_5823.php
	* May also work on other similar models
	*
	* (c) Copyright 2002 Justin Cormack <justin@street-vision.com>
	*
	* Release 0.02
	*
	* Based on advantechwdt.c which is based on wdt.c.
	* Original copyright messages:
	*
	* (c) Copyright 1996-1997 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>
	*
	*/

	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

	#include <linux/module.h>
	#include <linux/moduleparam.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 <linux/spinlock.h>
	#include <linux/io.h>
	#include <linux/uaccess.h>

	#define WATCHDOG_NAME "Wafer 5823 WDT"
	#define PFX WATCHDOG_NAME ": "
	#define WD_TIMO 60 /* 60 sec default timeout */

	static unsigned long wafwdt_is_open;
	static char expect_close;
	static DEFINE_SPINLOCK(wafwdt_lock);

	/*
	* You must set these - there is no sane way to probe for this board.
	*
	* To enable, write the timeout value in seconds (1 to 255) to I/O
	* port WDT_START, then read the port to start the watchdog. To pat
	* the dog, read port WDT_STOP to stop the timer, then read WDT_START
	* to restart it again.
	*/

	static int wdt_stop = 0x843;
	static int wdt_start = 0x443;

	static int timeout = WD_TIMO; /* in seconds */
	module_param(timeout, int, 0);
	MODULE_PARM_DESC(timeout,
	"Watchdog timeout in seconds. 1 <= timeout <= 255, default="
	__MODULE_STRING(WD_TIMO) ".");

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

	static void wafwdt_ping(void)
	{
	/* pat watchdog */
	spin_lock(&wafwdt_lock);
	inb_p(wdt_stop);
	inb_p(wdt_start);
	spin_unlock(&wafwdt_lock);
	}

	static void wafwdt_start(void)
	{
	/* start up watchdog */
	outb_p(timeout, wdt_start);
	inb_p(wdt_start);
	}

	static void wafwdt_stop(void)
	{
	/* stop watchdog */
	inb_p(wdt_stop);
	}

	static ssize_t wafwdt_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;

	/* In case it was set long 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 */
	wafwdt_ping();
	}
	return count;
	}

	static long wafwdt_ioctl(struct file *file, unsigned int cmd,
	unsigned long arg)
	{
	int new_timeout;
	void __user argp = (void __user )arg;
	int __user *p = argp;
	static const struct watchdog_info ident = {
	.options = WDIOF_KEEPALIVEPING \| WDIOF_SETTIMEOUT \|
	WDIOF_MAGICCLOSE,
	.firmware_version = 1,
	.identity = "Wafer 5823 WDT",
	};

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

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

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

	if (get_user(options, p))
	return -EFAULT;

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

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

	return retval;
	}

	case WDIOC_KEEPALIVE:
	wafwdt_ping();
	break;

	case WDIOC_SETTIMEOUT:
	if (get_user(new_timeout, p))
	return -EFAULT;
	if ((new_timeout < 1) \|\| (new_timeout > 255))
	return -EINVAL;
	timeout = new_timeout;
	wafwdt_stop();
	wafwdt_start();
	/* Fall */
	case WDIOC_GETTIMEOUT:
	return put_user(timeout, p);

	default:
	return -ENOTTY;
	}
	return 0;
	}

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

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

	static int wafwdt_close(struct inode inode, struct file file)
	{
	if (expect_close == 42)
	wafwdt_stop();
	else {
	pr_crit("WDT device closed unexpectedly. WDT will not stop!\n");
	wafwdt_ping();
	}
	clear_bit(0, &wafwdt_is_open);
	expect_close = 0;
	return 0;
	}

	/*
	* Notifier for system down
	*/

	static int wafwdt_notify_sys(struct notifier_block *this, unsigned long code,
	void *unused)
	{
	if (code == SYS_DOWN \|\| code == SYS_HALT)
	wafwdt_stop();
	return NOTIFY_DONE;
	}

	/*
	* Kernel Interfaces
	*/

	static const struct file_operations wafwdt_fops = {
	.owner = THIS_MODULE,
	.llseek = no_llseek,
	.write = wafwdt_write,
	.unlocked_ioctl = wafwdt_ioctl,
	.open = wafwdt_open,
	.release = wafwdt_close,
	};

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

	/*
	* The WDT needs to learn about soft shutdowns in order to
	* turn the timebomb registers off.
	*/

	static struct notifier_block wafwdt_notifier = {
	.notifier_call = wafwdt_notify_sys,
	};

	static int __init wafwdt_init(void)
	{
	int ret;

	pr_info("WDT driver for Wafer 5823 single board computer initialising\n");

	if (timeout < 1 \|\| timeout > 255) {
	timeout = WD_TIMO;
	pr_info("timeout value must be 1 <= x <= 255, using %d\n",
	timeout);
	}

	if (wdt_stop != wdt_start) {
	if (!request_region(wdt_stop, 1, "Wafer 5823 WDT")) {
	pr_err("I/O address 0x%04x already in use\n", wdt_stop);
	ret = -EIO;
	goto error;
	}
	}

	if (!request_region(wdt_start, 1, "Wafer 5823 WDT")) {
	pr_err("I/O address 0x%04x already in use\n", wdt_start);
	ret = -EIO;
	goto error2;
	}

	ret = register_reboot_notifier(&wafwdt_notifier);
	if (ret != 0) {
	pr_err("cannot register reboot notifier (err=%d)\n", ret);
	goto error3;
	}

	ret = misc_register(&wafwdt_miscdev);
	if (ret != 0) {
	pr_err("cannot register miscdev on minor=%d (err=%d)\n",
	WATCHDOG_MINOR, ret);
	goto error4;
	}

	pr_info("initialized. timeout=%d sec (nowayout=%d)\n",
	timeout, nowayout);

	return ret;
	error4:
	unregister_reboot_notifier(&wafwdt_notifier);
	error3:
	release_region(wdt_start, 1);
	error2:
	if (wdt_stop != wdt_start)
	release_region(wdt_stop, 1);
	error:
	return ret;
	}

	static void __exit wafwdt_exit(void)
	{
	misc_deregister(&wafwdt_miscdev);
	unregister_reboot_notifier(&wafwdt_notifier);
	if (wdt_stop != wdt_start)
	release_region(wdt_stop, 1);
	release_region(wdt_start, 1);
	}

	module_init(wafwdt_init);
	module_exit(wafwdt_exit);

	MODULE_AUTHOR("Justin Cormack");
	MODULE_DESCRIPTION("ICP Wafer 5823 Single Board Computer WDT driver");
	MODULE_LICENSE("GPL");

	/* end of wafer5823wdt.c */