linux-imx

/*

 * Watchdog driver for Cirrus Logic EP93xx family of devices.

 *

 * Copyright (c) 2004 Ray Lehtiniemi

 * Copyright (c) 2006 Tower Technologies

 * Based on ep93xx driver, bits from alim7101_wdt.c

 *

 * Authors: Ray Lehtiniemi <rayl@mail.com>,

 *  Alessandro Zummo <a.zummo@towertech.it>

 *

 * Copyright (c) 2012 H Hartley Sweeten <hsweeten@visionengravers.com>

 *  Convert to a platform device and use the watchdog framework API

 *

 * 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.

 *

 * This watchdog fires after 250msec, which is a too short interval

 * for us to rely on the user space daemon alone. So we ping the

 * wdt each ~200msec and eventually stop doing it if the user space

 * daemon dies.

 */

​

#include <linux/platform_device.h>

#include <linux/module.h>

#include <linux/watchdog.h>

#include <linux/io.h>

​

/* default timeout (secs) */

#define WDT_TIMEOUT 30

​

static bool nowayout = WATCHDOG_NOWAYOUT;

module_param(nowayout, bool, 0);

MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");

​

static unsigned int timeout;

module_param(timeout, uint, 0);

MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds.");

​

#define EP93XX_WATCHDOG     0x00

#define EP93XX_WDSTATUS     0x04

​

struct ep93xx_wdt_priv {

    void __iomem *mmio;

    struct watchdog_device wdd;

};

​

static int ep93xx_wdt_start(struct watchdog_device *wdd)

{

    struct ep93xx_wdt_priv *priv = watchdog_get_drvdata(wdd);

​

    writel(0xaaaa, priv->mmio + EP93XX_WATCHDOG);

​

    return 0;

}

​

static int ep93xx_wdt_stop(struct watchdog_device *wdd)

{

    struct ep93xx_wdt_priv *priv = watchdog_get_drvdata(wdd);

​

    writel(0xaa55, priv->mmio + EP93XX_WATCHDOG);

​

    return 0;