linux-imx

// SPDX-License-Identifier: GPL-2.0

/*

 * Watchdog timer driver for the WinSystems EBC-C384

 * Copyright (C) 2016 William Breathitt Gray

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License, version 2, as

 * published by the Free Software Foundation.

 *

 * This program is distributed in the hope that it will be useful, but

 * WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * General Public License for more details.

 */

#include <linux/device.h>

#include <linux/dmi.h>

#include <linux/errno.h>

#include <linux/io.h>

#include <linux/ioport.h>

#include <linux/isa.h>

#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/moduleparam.h>

#include <linux/types.h>

#include <linux/watchdog.h>

​

#define MODULE_NAME     "ebc-c384_wdt"

#define WATCHDOG_TIMEOUT    60

/*

 * The timeout value in minutes must fit in a single byte when sent to the

 * watchdog timer; the maximum timeout possible is 15300 (255 * 60) seconds.

 */

#define WATCHDOG_MAX_TIMEOUT    15300

#define BASE_ADDR       0x564

#define ADDR_EXTENT     5

#define CFG_ADDR        (BASE_ADDR + 1)

#define PET_ADDR        (BASE_ADDR + 2)

​

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) ")");

​

static unsigned timeout;

module_param(timeout, uint, 0);

MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds (default="

    __MODULE_STRING(WATCHDOG_TIMEOUT) ")");

​

static int ebc_c384_wdt_start(struct watchdog_device *wdev)

{

    unsigned t = wdev->timeout;

​

    /* resolution is in minutes for timeouts greater than 255 seconds */

    if (t > 255)

        t = DIV_ROUND_UP(t, 60);

​

    outb(t, PET_ADDR);

​

    return 0;

}

​

static int ebc_c384_wdt_stop(struct watchdog_device *wdev)

{