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/*
 * sma cpu5 watchdog driver
 *
 * Copyright (C) 2003 Heiko Ronsdorf <hero@ihg.uni-duisburg.de>
 *
 * 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.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 */
 
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/miscdevice.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/ioport.h>
#include <linux/timer.h>
#include <linux/completion.h>
#include <linux/jiffies.h>
#include <asm/io.h>
#include <asm/uaccess.h>
 
#include <linux/watchdog.h>
 
/* adjustable parameters */
 
static int verbose = 0;
static int port = 0x91;
static int ticks = 10000;
 
#define PFX			"cpu5wdt: "
 
#define CPU5WDT_EXTENT          0x0A
 
#define CPU5WDT_STATUS_REG      0x00
#define CPU5WDT_TIME_A_REG      0x02
#define CPU5WDT_TIME_B_REG      0x03
#define CPU5WDT_MODE_REG        0x04
#define CPU5WDT_TRIGGER_REG     0x07
#define CPU5WDT_ENABLE_REG      0x08
#define CPU5WDT_RESET_REG       0x09
 
#define CPU5WDT_INTERVAL	(HZ/10+1)
 
/* some device data */
 
static struct {
	struct completion stop;
	volatile int running;
	struct timer_list timer;
	volatile int queue;
	int default_ticks;
	unsigned long inuse;
} cpu5wdt_device;
 
/* generic helper functions */
 
static void cpu5wdt_trigger(unsigned long unused)
{
	if ( verbose > 2 )
		printk(KERN_DEBUG PFX "trigger at %i ticks\n", ticks);
 
	if( cpu5wdt_device.running )
		ticks--;
 
	/* keep watchdog alive */
	outb(1, port + CPU5WDT_TRIGGER_REG);
 
	/* requeue?? */
	if (cpu5wdt_device.queue && ticks)
		mod_timer(&cpu5wdt_device.timer, jiffies + CPU5WDT_INTERVAL);
	else {
		/* ticks doesn't matter anyway */
		complete(&cpu5wdt_device.stop);
	}
 
}
 
static void cpu5wdt_reset(void)
{
	ticks = cpu5wdt_device.default_ticks;
 
	if ( verbose )
		printk(KERN_DEBUG PFX "reset (%i ticks)\n", (int) ticks);
 
}
 
static void cpu5wdt_start(void)
{
	if ( !cpu5wdt_device.queue ) {
		cpu5wdt_device.queue = 1;
		outb(0, port + CPU5WDT_TIME_A_REG);
		outb(0, port + CPU5WDT_TIME_B_REG);
		outb(1, port + CPU5WDT_MODE_REG);
		outb(0, port + CPU5WDT_RESET_REG);
		outb(0, port + CPU5WDT_ENABLE_REG);
		mod_timer(&cpu5wdt_device.timer, jiffies + CPU5WDT_INTERVAL);
	}
	/* if process dies, counter is not decremented */
	cpu5wdt_device.running++;
}
 
static int cpu5wdt_stop(void)
{
	if ( cpu5wdt_device.running )
		cpu5wdt_device.running = 0;
 
	ticks = cpu5wdt_device.default_ticks;
 
	if ( verbose )
		printk(KERN_CRIT PFX "stop not possible\n");
 
	return -EIO;
}
 
/* filesystem operations */
 
static int cpu5wdt_open(struct inode *inode, struct file *file)
{
	if ( test_and_set_bit(0, &cpu5wdt_device.inuse) )
		return -EBUSY;
 
	return nonseekable_open(inode, file);
}
 
static int cpu5wdt_release(struct inode *inode, struct file *file)
{
	clear_bit(0, &cpu5wdt_device.inuse);
	return 0;
}
 
static int cpu5wdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
{
	void __user *argp = (void __user *)arg;
	unsigned int value;
	static struct watchdog_info ident =
	{
		.options = WDIOF_CARDRESET,
		.identity = "CPU5 WDT",
	};
 
	switch(cmd) {
		case WDIOC_KEEPALIVE:
			cpu5wdt_reset();
			break;
		case WDIOC_GETSTATUS:
			value = inb(port + CPU5WDT_STATUS_REG);
			value = (value >> 2) & 1;
			if ( copy_to_user(argp, &value, sizeof(int)) )
				return -EFAULT;
			break;
		case WDIOC_GETBOOTSTATUS:
			if ( copy_to_user(argp, &value, sizeof(int)) )
				return -EFAULT;
			break;
		case WDIOC_GETSUPPORT:
			if ( copy_to_user(argp, &ident, sizeof(ident)) )
				return -EFAULT;
			break;
		case WDIOC_SETOPTIONS:
			if ( copy_from_user(&value, argp, sizeof(int)) )
				return -EFAULT;
			switch(value) {
				case WDIOS_ENABLECARD:
					cpu5wdt_start();
					break;
				case WDIOS_DISABLECARD:
					return cpu5wdt_stop();
				default:
					return -EINVAL;
			}
			break;
		default:
    			return -ENOTTY;
	}
	return 0;
}
 
static ssize_t cpu5wdt_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
{
	if ( !count )
		return -EIO;
 
	cpu5wdt_reset();
 
	return count;
}
 
static const struct file_operations cpu5wdt_fops = {
	.owner		= THIS_MODULE,
	.llseek		= no_llseek,
	.ioctl		= cpu5wdt_ioctl,
	.open		= cpu5wdt_open,
	.write		= cpu5wdt_write,
	.release	= cpu5wdt_release,
};
 
static struct miscdevice cpu5wdt_misc = {
	.minor	= WATCHDOG_MINOR,
	.name	= "watchdog",
	.fops	= &cpu5wdt_fops,
};
 
/* init/exit function */
 
static int __devinit cpu5wdt_init(void)
{
	unsigned int val;
	int err;
 
	if ( verbose )
		printk(KERN_DEBUG PFX "port=0x%x, verbose=%i\n", port, verbose);
 
	if ( !request_region(port, CPU5WDT_EXTENT, PFX) ) {
		printk(KERN_ERR PFX "request_region failed\n");
		err = -EBUSY;
		goto no_port;
	}
 
	if ( (err = misc_register(&cpu5wdt_misc)) < 0 ) {
		printk(KERN_ERR PFX "misc_register failed\n");
		goto no_misc;
	}
 
	/* watchdog reboot? */
	val = inb(port + CPU5WDT_STATUS_REG);
	val = (val >> 2) & 1;
	if ( !val )
		printk(KERN_INFO PFX "sorry, was my fault\n");
 
	init_completion(&cpu5wdt_device.stop);
	cpu5wdt_device.queue = 0;
 
	clear_bit(0, &cpu5wdt_device.inuse);
 
	setup_timer(&cpu5wdt_device.timer, cpu5wdt_trigger, 0);
 
	cpu5wdt_device.default_ticks = ticks;
 
	printk(KERN_INFO PFX "init success\n");
 
	return 0;
 
no_misc:
	release_region(port, CPU5WDT_EXTENT);
no_port:
	return err;
}
 
static int __devinit cpu5wdt_init_module(void)
{
	return cpu5wdt_init();
}
 
static void __devexit cpu5wdt_exit(void)
{
	if ( cpu5wdt_device.queue ) {
		cpu5wdt_device.queue = 0;
		wait_for_completion(&cpu5wdt_device.stop);
	}
 
	misc_deregister(&cpu5wdt_misc);
 
	release_region(port, CPU5WDT_EXTENT);
 
}
 
static void __devexit cpu5wdt_exit_module(void)
{
	cpu5wdt_exit();
}
 
/* module entry points */
 
module_init(cpu5wdt_init_module);
module_exit(cpu5wdt_exit_module);
 
MODULE_AUTHOR("Heiko Ronsdorf <hero@ihg.uni-duisburg.de>");
MODULE_DESCRIPTION("sma cpu5 watchdog driver");
MODULE_SUPPORTED_DEVICE("sma cpu5 watchdog");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 
module_param(port, int, 0);
MODULE_PARM_DESC(port, "base address of watchdog card, default is 0x91");
 
module_param(verbose, int, 0);
MODULE_PARM_DESC(verbose, "be verbose, default is 0 (no)");
 
module_param(ticks, int, 0);
MODULE_PARM_DESC(ticks, "count down ticks, default is 10000");