linux/drivers/watchdog/ib700wdt.c

// SPDX-License-Identifier: GPL-2.0+
/*
 *	IB700 Single Board Computer WDT driver
 *
 *	(c) Copyright 2001 Charles Howes <[email protected]>
 *
 *	Based on advantechwdt.c which is based on acquirewdt.c which
 *	is based on wdt.c.
 *
 *	(c) Copyright 2000-2001 Marek Michalkiewicz <[email protected]>
 *
 *	Based on acquirewdt.c which is based on wdt.c.
 *	Original copyright messages:
 *
 *	(c) Copyright 1996 Alan Cox <[email protected]>,
 *						All Rights Reserved.
 *
 *	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 <[email protected]>
 *
 *	14-Dec-2001 Matt Domsch <[email protected]>
 *	     Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT
 *	     Added timeout module option to override default
 *
 */

#define pr_fmt(fmt) …

#include <linux/module.h>
#include <linux/types.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/ioport.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/moduleparam.h>
#include <linux/platform_device.h>
#include <linux/io.h>
#include <linux/uaccess.h>


static struct platform_device *ibwdt_platform_device;
static unsigned long ibwdt_is_open;
static DEFINE_SPINLOCK(ibwdt_lock);
static char expect_close;

/* Module information */
#define DRV_NAME …

/*
 *
 * Watchdog Timer Configuration
 *
 * The function of the watchdog timer is to reset the system
 * automatically and is defined at I/O port 0443H.  To enable the
 * watchdog timer and allow the system to reset, write I/O port 0443H.
 * To disable the timer, write I/O port 0441H for the system to stop the
 * watchdog function.  The timer has a tolerance of 20% for its
 * intervals.
 *
 * The following describes how the timer should be programmed.
 *
 * Enabling Watchdog:
 * MOV AX,000FH (Choose the values from 0 to F)
 * MOV DX,0443H
 * OUT DX,AX
 *
 * Disabling Watchdog:
 * MOV AX,000FH (Any value is fine.)
 * MOV DX,0441H
 * OUT DX,AX
 *
 * Watchdog timer control table:
 * Level   Value  Time/sec | Level Value Time/sec
 *   1       F       0     |   9     7      16
 *   2       E       2     |   10    6      18
 *   3       D       4     |   11    5      20
 *   4       C       6     |   12    4      22
 *   5       B       8     |   13    3      24
 *   6       A       10    |   14    2      26
 *   7       9       12    |   15    1      28
 *   8       8       14    |   16    0      30
 *
 */

#define WDT_STOP …
#define WDT_START …

/* Default timeout */
#define WATCHDOG_TIMEOUT …
static int timeout = …;	/* in seconds */
module_param(timeout, int, 0);
MODULE_PARM_DESC(…) …;

static bool nowayout = … WATCHDOG_NOWAYOUT;
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(…) …;


/*
 *	Watchdog Operations
 */

static void ibwdt_ping(void)
{ … }

static void ibwdt_disable(void)
{ … }

static int ibwdt_set_heartbeat(int t)
{ … }

/*
 *	/dev/watchdog handling
 */

static ssize_t ibwdt_write(struct file *file, const char __user *buf,
						size_t count, loff_t *ppos)
{ … }

static long ibwdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{ … }

static int ibwdt_open(struct inode *inode, struct file *file)
{ … }

static int ibwdt_close(struct inode *inode, struct file *file)
{ … }

/*
 *	Kernel Interfaces
 */

static const struct file_operations ibwdt_fops = …;

static struct miscdevice ibwdt_miscdev = …;

/*
 *	Init & exit routines
 */

static int __init ibwdt_probe(struct platform_device *dev)
{ … }

static void ibwdt_remove(struct platform_device *dev)
{ … }

static void ibwdt_shutdown(struct platform_device *dev)
{ … }

static struct platform_driver ibwdt_driver = …;

static int __init ibwdt_init(void)
{ … }

static void __exit ibwdt_exit(void)
{ … }

module_init(…) …;
module_exit(ibwdt_exit);

MODULE_AUTHOR(…) …;
MODULE_DESCRIPTION(…) …;
MODULE_LICENSE(…) …;

/* end of ib700wdt.c */