// SPDX-License-Identifier: GPL-2.0+
/*
* Advantech Single Board Computer WDT driver
*
* (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
*
* 16-Oct-2002 Rob Radez <[email protected]>
* Clean up ioctls, clean up init + exit, add expect close support,
* add wdt_start and wdt_stop as parameters.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/fs.h>
#include <linux/ioport.h>
#include <linux/platform_device.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/uaccess.h>
#define DRV_NAME "advantechwdt"
#define WATCHDOG_NAME "Advantech WDT"
#define WATCHDOG_TIMEOUT 60 /* 60 sec default timeout */
/* the watchdog platform device */
static struct platform_device *advwdt_platform_device;
static unsigned long advwdt_is_open;
static char adv_expect_close;
/*
* You must set these - there is no sane way to probe for this board.
*
* To enable or restart, write the timeout value in seconds (1 to 63)
* to I/O port wdt_start. To disable, read I/O port wdt_stop.
* Both are 0x443 for most boards (tested on a PCA-6276VE-00B1), but
* check your manual (at least the PCA-6159 seems to be different -
* the manual says wdt_stop is 0x43, not 0x443).
* (0x43 is also a write-only control register for the 8254 timer!)
*/
static int wdt_stop = 0x443;
module_param(wdt_stop, int, 0);
MODULE_PARM_DESC(wdt_stop, "Advantech WDT 'stop' io port (default 0x443)");
static int wdt_start = 0x443;
module_param(wdt_start, int, 0);
MODULE_PARM_DESC(wdt_start, "Advantech WDT 'start' io port (default 0x443)");
static int timeout = WATCHDOG_TIMEOUT; /* in seconds */
module_param(timeout, int, 0);
MODULE_PARM_DESC(timeout,
"Watchdog timeout in seconds. 1<= timeout <=63, default="
__MODULE_STRING(WATCHDOG_TIMEOUT) ".");
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) ")");
/*
* Watchdog Operations
*/
static void advwdt_ping(void)
{
/* Write a watchdog value */
outb_p(timeout, wdt_start);
}
static void advwdt_disable(void)
{
inb_p(wdt_stop);
}
static int advwdt_set_heartbeat(int t)
{
if (t < 1 || t > 63)
return -EINVAL;
timeout = t;
return 0;
}
/*
* /dev/watchdog handling
*/
static ssize_t advwdt_write(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
if (count) {
if (!nowayout) {
size_t i;
adv_expect_close = 0;
for (i = 0; i != count; i++) {
char c;
if (get_user(c, buf + i))
return -EFAULT;
if (c == 'V')
adv_expect_close = 42;
}
}
advwdt_ping();
}
return count;
}
static long advwdt_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 = WATCHDOG_NAME,
};
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) {
advwdt_disable();
retval = 0;
}
if (options & WDIOS_ENABLECARD) {
advwdt_ping();
retval = 0;
}
return retval;
}
case WDIOC_KEEPALIVE:
advwdt_ping();
break;
case WDIOC_SETTIMEOUT:
if (get_user(new_timeout, p))
return -EFAULT;
if (advwdt_set_heartbeat(new_timeout))
return -EINVAL;
advwdt_ping();
fallthrough;
case WDIOC_GETTIMEOUT:
return put_user(timeout, p);
default:
return -ENOTTY;
}
return 0;
}
static int advwdt_open(struct inode *inode, struct file *file)
{
if (test_and_set_bit(0, &advwdt_is_open))
return -EBUSY;
/*
* Activate
*/
advwdt_ping();
return stream_open(inode, file);
}
static int advwdt_close(struct inode *inode, struct file *file)
{
if (adv_expect_close == 42) {
advwdt_disable();
} else {
pr_crit("Unexpected close, not stopping watchdog!\n");
advwdt_ping();
}
clear_bit(0, &advwdt_is_open);
adv_expect_close = 0;
return 0;
}
/*
* Kernel Interfaces
*/
static const struct file_operations advwdt_fops = {
.owner = THIS_MODULE,
.write = advwdt_write,
.unlocked_ioctl = advwdt_ioctl,
.compat_ioctl = compat_ptr_ioctl,
.open = advwdt_open,
.release = advwdt_close,
};
static struct miscdevice advwdt_miscdev = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &advwdt_fops,
};
/*
* Init & exit routines
*/
static int __init advwdt_probe(struct platform_device *dev)
{
int ret;
if (wdt_stop != wdt_start) {
if (!request_region(wdt_stop, 1, WATCHDOG_NAME)) {
pr_err("I/O address 0x%04x already in use\n",
wdt_stop);
ret = -EIO;
goto out;
}
}
if (!request_region(wdt_start, 1, WATCHDOG_NAME)) {
pr_err("I/O address 0x%04x already in use\n", wdt_start);
ret = -EIO;
goto unreg_stop;
}
/* Check that the heartbeat value is within it's range ;
* if not reset to the default */
if (advwdt_set_heartbeat(timeout)) {
advwdt_set_heartbeat(WATCHDOG_TIMEOUT);
pr_info("timeout value must be 1<=x<=63, using %d\n", timeout);
}
ret = misc_register(&advwdt_miscdev);
if (ret != 0) {
pr_err("cannot register miscdev on minor=%d (err=%d)\n",
WATCHDOG_MINOR, ret);
goto unreg_regions;
}
pr_info("initialized. timeout=%d sec (nowayout=%d)\n",
timeout, nowayout);
out:
return ret;
unreg_regions:
release_region(wdt_start, 1);
unreg_stop:
if (wdt_stop != wdt_start)
release_region(wdt_stop, 1);
goto out;
}
static void advwdt_remove(struct platform_device *dev)
{
misc_deregister(&advwdt_miscdev);
release_region(wdt_start, 1);
if (wdt_stop != wdt_start)
release_region(wdt_stop, 1);
}
static void advwdt_shutdown(struct platform_device *dev)
{
/* Turn the WDT off if we have a soft shutdown */
advwdt_disable();
}
static struct platform_driver advwdt_driver = {
.remove_new = advwdt_remove,
.shutdown = advwdt_shutdown,
.driver = {
.name = DRV_NAME,
},
};
static int __init advwdt_init(void)
{
int err;
pr_info("WDT driver for Advantech single board computer initialising\n");
advwdt_platform_device = platform_device_register_simple(DRV_NAME,
-1, NULL, 0);
if (IS_ERR(advwdt_platform_device))
return PTR_ERR(advwdt_platform_device);
err = platform_driver_probe(&advwdt_driver, advwdt_probe);
if (err)
goto unreg_platform_device;
return 0;
unreg_platform_device:
platform_device_unregister(advwdt_platform_device);
return err;
}
static void __exit advwdt_exit(void)
{
platform_device_unregister(advwdt_platform_device);
platform_driver_unregister(&advwdt_driver);
pr_info("Watchdog Module Unloaded\n");
}
module_init(advwdt_init);
module_exit(advwdt_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Marek Michalkiewicz <[email protected]>");
MODULE_DESCRIPTION("Advantech Single Board Computer WDT driver");
Codebase Browser
linux