linux-imx

/*

 *  60xx Single Board Computer Watchdog Timer driver for Linux 2.2.x

 *

 *  Based on acquirewdt.c by Alan Cox.

 *

 *  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.

 *

 *  The author does NOT admit liability nor provide warranty for

 *  any of this software. This material is provided "AS-IS" in

 *  the hope that it may be useful for others.

 *

 *  (c) Copyright 2000    Jakob Oestergaard <jakob@unthought.net>

 *

 *           12/4 - 2000      [Initial revision]

 *           25/4 - 2000      Added /dev/watchdog support

 *           09/5 - 2001      [smj@oro.net] fixed fop_write to "return 1"

 *                  on success

 *           12/4 - 2002      [rob@osinvestor.com] eliminate fop_read

 *                            fix possible wdt_is_open race

 *                            add CONFIG_WATCHDOG_NOWAYOUT support

 *                            remove lock_kernel/unlock_kernel pairs

 *                            added KERN_* to printk's

 *                            got rid of extraneous comments

 *                            changed watchdog_info to correctly reflect what

 *                the driver offers

 *                added WDIOC_GETSTATUS, WDIOC_GETBOOTSTATUS,

 *                WDIOC_SETTIMEOUT, WDIOC_GETTIMEOUT, and

 *                WDIOC_SETOPTIONS ioctls

 *           09/8 - 2003      [wim@iguana.be] cleanup of trailing spaces

 *                            use module_param

 *                            made timeout (the emulated heartbeat) a

 *                module_param

 *                            made the keepalive ping an internal subroutine

 *                            made wdt_stop and wdt_start module params

 *                            added extra printk's for startup problems

 *                            added MODULE_AUTHOR and MODULE_DESCRIPTION info

 *

 *

 *  This WDT driver is different from the other Linux WDT

 *  drivers in the following ways:

 *  *)  The driver will ping the watchdog by itself, because this

 *      particular WDT has a very short timeout (one second) and it

 *      would be insane to count on any userspace daemon always

 *      getting scheduled within that time frame.

 *

 */

​

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

​

#include <linux/module.h>

#include <linux/moduleparam.h>

#include <linux/types.h>

#include <linux/timer.h>

#include <linux/jiffies.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/io.h>

#include <linux/uaccess.h>

​

​

#define OUR_NAME "sbc60xxwdt"

#define PFX OUR_NAME ": "

​

/*

 * You must set these - The driver cannot probe for the settings

 */

​

static int wdt_stop = 0x45;

module_param(wdt_stop, int, 0);

MODULE_PARM_DESC(wdt_stop, "SBC60xx WDT 'stop' io port (default 0x45)");

​

static int wdt_start = 0x443;

module_param(wdt_start, int, 0);

MODULE_PARM_DESC(wdt_start, "SBC60xx WDT 'start' io port (default 0x443)");

​

/*

 * The 60xx board can use watchdog timeout values from one second

 * to several minutes.  The default is one second, so if we reset

 * the watchdog every ~250ms we should be safe.

 */

​

#define WDT_INTERVAL (HZ/4+1)

​

/*