linux-imx

/*

 * 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;

    }