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/*
* Watchdog driver for SBC-FITPC2 board
*
* Author: Denis Turischev <denis@compulab.co.il>
*
* Adapted from the IXP2000 watchdog driver by Deepak Saxena.
*
* This file is licensed under the terms of the GNU General Public
* License version 2. This program is licensed "as is" without any
* warranty of any kind, whether express or implied.
*/
#define pr_fmt(fmt) KBUILD_MODNAME " WATCHDOG: " fmt
#include <linux/module.h>
#include <linux/types.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/ioport.h>
#include <linux/delay.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/moduleparam.h>
#include <linux/dmi.h>
#include <linux/io.h>
#include <linux/uaccess.h>
static bool nowayout = WATCHDOG_NOWAYOUT;
static unsigned int margin = 60; /* (secs) Default is 1 minute */
static unsigned long wdt_status;
static DEFINE_MUTEX(wdt_lock);
#define WDT_IN_USE 0
#define WDT_OK_TO_CLOSE 1
#define COMMAND_PORT 0x4c
#define DATA_PORT 0x48
#define IFACE_ON_COMMAND 1
#define REBOOT_COMMAND 2
#define WATCHDOG_NAME "SBC-FITPC2 Watchdog"
static void wdt_send_data(unsigned char command, unsigned char data)
{
outb(data, DATA_PORT);
msleep(200);
outb(command, COMMAND_PORT);
msleep(100);
}
static void wdt_enable(void)
{
mutex_lock(&wdt_lock);
wdt_send_data(IFACE_ON_COMMAND, 1);
wdt_send_data(REBOOT_COMMAND, margin);
mutex_unlock(&wdt_lock);
}
static void wdt_disable(void)
{
mutex_lock(&wdt_lock);
wdt_send_data(IFACE_ON_COMMAND, 0);
wdt_send_data(REBOOT_COMMAND, 0);
mutex_unlock(&wdt_lock);
}
static int fitpc2_wdt_open(struct inode *inode, struct file *file)
{
if (test_and_set_bit(WDT_IN_USE, &wdt_status))
return -EBUSY;
clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
wdt_enable();
return nonseekable_open(inode, file);
}
static ssize_t fitpc2_wdt_write(struct file *file, const char *data,
size_t len, loff_t *ppos)
{
size_t i;
if (!len)
return 0;
if (nowayout) {
len = 0;
goto out;
}
clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
for (i = 0; i != len; i++) {
char c;
if (get_user(c, data + i))
return -EFAULT;
if (c == 'V')
set_bit(WDT_OK_TO_CLOSE, &wdt_status);
}
out:
wdt_enable();
return len;
}
static const struct watchdog_info ident = {
.options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT |
WDIOF_KEEPALIVEPING,
.identity = WATCHDOG_NAME,
};
static long fitpc2_wdt_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
int ret = -ENOTTY;
int time;
switch (cmd) {
case WDIOC_GETSUPPORT:
ret = copy_to_user((struct watchdog_info *)arg, &ident,
sizeof(ident)) ? -EFAULT : 0;
break;
case WDIOC_GETSTATUS:
ret = put_user(0, (int *)arg);
break;
case WDIOC_GETBOOTSTATUS:
ret = put_user(0, (int *)arg);
break;
case WDIOC_KEEPALIVE:
wdt_enable();
ret = 0;
break;
case WDIOC_SETTIMEOUT:
ret = get_user(time, (int *)arg);
if (ret)
break;
if (time < 31 || time > 255) {
ret = -EINVAL;
break;
}
margin = time;
wdt_enable();
/* Fall through */
case WDIOC_GETTIMEOUT:
ret = put_user(margin, (int *)arg);
break;
}
return ret;
}
static int fitpc2_wdt_release(struct inode *inode, struct file *file)
{
if (test_bit(WDT_OK_TO_CLOSE, &wdt_status)) {
wdt_disable();
pr_info("Device disabled\n");
} else {
pr_warn("Device closed unexpectedly - timer will not stop\n");
wdt_enable();
}
clear_bit(WDT_IN_USE, &wdt_status);
clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
return 0;
}
static const struct file_operations fitpc2_wdt_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.write = fitpc2_wdt_write,
.unlocked_ioctl = fitpc2_wdt_ioctl,
.open = fitpc2_wdt_open,
.release = fitpc2_wdt_release,
};
static struct miscdevice fitpc2_wdt_miscdev = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &fitpc2_wdt_fops,
};
static int __init fitpc2_wdt_init(void)
{
int err;
const char *brd_name;
brd_name = dmi_get_system_info(DMI_BOARD_NAME);
if (!brd_name || !strstr(brd_name, "SBC-FITPC2"))
return -ENODEV;
pr_info("%s found\n", brd_name);
if (!request_region(COMMAND_PORT, 1, WATCHDOG_NAME)) {
pr_err("I/O address 0x%04x already in use\n", COMMAND_PORT);
return -EIO;
}
if (!request_region(DATA_PORT, 1, WATCHDOG_NAME)) {
pr_err("I/O address 0x%04x already in use\n", DATA_PORT);
err = -EIO;
goto err_data_port;
}
if (margin < 31 || margin > 255) {
pr_err("margin must be in range 31 - 255 seconds, you tried to set %d\n",
margin);
err = -EINVAL;
goto err_margin;
}
err = misc_register(&fitpc2_wdt_miscdev);
if (err) {
pr_err("cannot register miscdev on minor=%d (err=%d)\n",
WATCHDOG_MINOR, err);
goto err_margin;
}
return 0;
err_margin:
release_region(DATA_PORT, 1);
err_data_port:
release_region(COMMAND_PORT, 1);
return err;
}
static void __exit fitpc2_wdt_exit(void)
{
misc_deregister(&fitpc2_wdt_miscdev);
release_region(DATA_PORT, 1);
release_region(COMMAND_PORT, 1);
}
module_init(fitpc2_wdt_init);
module_exit(fitpc2_wdt_exit);
MODULE_AUTHOR("Denis Turischev <denis@compulab.co.il>");
MODULE_DESCRIPTION("SBC-FITPC2 Watchdog");
module_param(margin, int, 0);
MODULE_PARM_DESC(margin, "Watchdog margin in seconds (default 60s)");
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
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