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/*
* SBC EPX C3 0.1 A Hardware Watchdog Device for the Winsystems EPX - C3
* single board computer
*
* ( c ) Copyright 2006 Calin A . Culianu < calin @ ajvar . org > , 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 .
*
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* based on softdog . c by Alan Cox < alan @ lxorguk . ukuu . org . uk >
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*/
# include <linux/module.h>
# include <linux/moduleparam.h>
# include <linux/types.h>
# include <linux/kernel.h>
# include <linux/fs.h>
# include <linux/mm.h>
# include <linux/miscdevice.h>
# include <linux/watchdog.h>
# include <linux/notifier.h>
# include <linux/reboot.h>
# include <linux/init.h>
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# include <linux/ioport.h>
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# include <linux/uaccess.h>
# include <linux/io.h>
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# define PFX "epx_c3: "
static int epx_c3_alive ;
# define WATCHDOG_TIMEOUT 1 /* 1 sec default timeout */
static int nowayout = WATCHDOG_NOWAYOUT ;
module_param ( nowayout , int , 0 ) ;
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MODULE_PARM_DESC ( nowayout , " Watchdog cannot be stopped once started (default= " __MODULE_STRING ( WATCHDOG_NOWAYOUT ) " ) " ) ;
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# define EPXC3_WATCHDOG_CTL_REG 0x1ee /* write 1 to enable, 0 to disable */
# define EPXC3_WATCHDOG_PET_REG 0x1ef /* write anything to pet once enabled */
static void epx_c3_start ( void )
{
outb ( 1 , EPXC3_WATCHDOG_CTL_REG ) ;
}
static void epx_c3_stop ( void )
{
outb ( 0 , EPXC3_WATCHDOG_CTL_REG ) ;
printk ( KERN_INFO PFX " Stopped watchdog timer. \n " ) ;
}
static void epx_c3_pet ( void )
{
outb ( 1 , EPXC3_WATCHDOG_PET_REG ) ;
}
/*
* Allow only one person to hold it open
*/
static int epx_c3_open ( struct inode * inode , struct file * file )
{
if ( epx_c3_alive )
return - EBUSY ;
if ( nowayout )
__module_get ( THIS_MODULE ) ;
/* Activate timer */
epx_c3_start ( ) ;
epx_c3_pet ( ) ;
epx_c3_alive = 1 ;
printk ( KERN_INFO " Started watchdog timer. \n " ) ;
return nonseekable_open ( inode , file ) ;
}
static int epx_c3_release ( struct inode * inode , struct file * file )
{
/* Shut off the timer.
* Lock it in if it ' s a module and we defined . . . NOWAYOUT */
if ( ! nowayout )
epx_c3_stop ( ) ; /* Turn the WDT off */
epx_c3_alive = 0 ;
return 0 ;
}
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static ssize_t epx_c3_write ( struct file * file , const char __user * data ,
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size_t len , loff_t * ppos )
{
/* Refresh the timer. */
if ( len )
epx_c3_pet ( ) ;
return len ;
}
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static long epx_c3_ioctl ( struct file * file , unsigned int cmd ,
unsigned long arg )
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{
int options , retval = - EINVAL ;
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int __user * argp = ( void __user * ) arg ;
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static const struct watchdog_info ident = {
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. options = WDIOF_KEEPALIVEPING |
WDIOF_MAGICCLOSE ,
. firmware_version = 0 ,
. identity = " Winsystems EPX-C3 H/W Watchdog " ,
} ;
switch ( cmd ) {
case WDIOC_GETSUPPORT :
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if ( copy_to_user ( argp , & ident , sizeof ( ident ) ) )
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return - EFAULT ;
return 0 ;
case WDIOC_GETSTATUS :
case WDIOC_GETBOOTSTATUS :
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return put_user ( 0 , argp ) ;
case WDIOC_SETOPTIONS :
if ( get_user ( options , argp ) )
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return - EFAULT ;
if ( options & WDIOS_DISABLECARD ) {
epx_c3_stop ( ) ;
retval = 0 ;
}
if ( options & WDIOS_ENABLECARD ) {
epx_c3_start ( ) ;
retval = 0 ;
}
return retval ;
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case WDIOC_KEEPALIVE :
epx_c3_pet ( ) ;
return 0 ;
case WDIOC_GETTIMEOUT :
return put_user ( WATCHDOG_TIMEOUT , argp ) ;
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default :
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return - ENOTTY ;
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}
}
static int epx_c3_notify_sys ( struct notifier_block * this , unsigned long code ,
void * unused )
{
if ( code = = SYS_DOWN | | code = = SYS_HALT )
epx_c3_stop ( ) ; /* Turn the WDT off */
return NOTIFY_DONE ;
}
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static const struct file_operations epx_c3_fops = {
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. owner = THIS_MODULE ,
. llseek = no_llseek ,
. write = epx_c3_write ,
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. unlocked_ioctl = epx_c3_ioctl ,
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. open = epx_c3_open ,
. release = epx_c3_release ,
} ;
static struct miscdevice epx_c3_miscdev = {
. minor = WATCHDOG_MINOR ,
. name = " watchdog " ,
. fops = & epx_c3_fops ,
} ;
static struct notifier_block epx_c3_notifier = {
. notifier_call = epx_c3_notify_sys ,
} ;
static const char banner [ ] __initdata =
KERN_INFO PFX " Hardware Watchdog Timer for Winsystems EPX-C3 SBC: 0.1 \n " ;
static int __init watchdog_init ( void )
{
int ret ;
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if ( ! request_region ( EPXC3_WATCHDOG_CTL_REG , 2 , " epxc3_watchdog " ) )
return - EBUSY ;
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ret = register_reboot_notifier ( & epx_c3_notifier ) ;
if ( ret ) {
printk ( KERN_ERR PFX " cannot register reboot notifier "
" (err=%d) \n " , ret ) ;
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goto out ;
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}
ret = misc_register ( & epx_c3_miscdev ) ;
if ( ret ) {
printk ( KERN_ERR PFX " cannot register miscdev on minor=%d "
" (err=%d) \n " , WATCHDOG_MINOR , ret ) ;
unregister_reboot_notifier ( & epx_c3_notifier ) ;
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goto out ;
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}
printk ( banner ) ;
return 0 ;
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out :
release_region ( EPXC3_WATCHDOG_CTL_REG , 2 ) ;
return ret ;
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}
static void __exit watchdog_exit ( void )
{
misc_deregister ( & epx_c3_miscdev ) ;
unregister_reboot_notifier ( & epx_c3_notifier ) ;
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release_region ( EPXC3_WATCHDOG_CTL_REG , 2 ) ;
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}
module_init ( watchdog_init ) ;
module_exit ( watchdog_exit ) ;
MODULE_AUTHOR ( " Calin A. Culianu <calin@ajvar.org> " ) ;
MODULE_DESCRIPTION ( " Hardware Watchdog Device for Winsystems EPX-C3 SBC. Note that there is no way to probe for this device -- so only use it if you are *sure* you are runnning on this specific SBC system from Winsystems! It writes to IO ports 0x1ee and 0x1ef! " ) ;
MODULE_LICENSE ( " GPL " ) ;
MODULE_ALIAS_MISCDEV ( WATCHDOG_MINOR ) ;