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// SPDX-License-Identifier: GPL-2.0-only
/*
* 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 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;
}
static int ep93xx_wdt_ping(struct watchdog_device *wdd)
{
struct ep93xx_wdt_priv *priv = watchdog_get_drvdata(wdd);
writel(0x5555, priv->mmio + EP93XX_WATCHDOG);
return 0;
}
static const struct watchdog_info ep93xx_wdt_ident = {
.options = WDIOF_CARDRESET |
WDIOF_SETTIMEOUT |
WDIOF_MAGICCLOSE |
WDIOF_KEEPALIVEPING,
.identity = "EP93xx Watchdog",
};
static const struct watchdog_ops ep93xx_wdt_ops = {
.owner = THIS_MODULE,
.start = ep93xx_wdt_start,
.stop = ep93xx_wdt_stop,
.ping = ep93xx_wdt_ping,
};
static int ep93xx_wdt_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct ep93xx_wdt_priv *priv;
struct watchdog_device *wdd;
unsigned long val;
int ret;
priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
if (!priv)
return -ENOMEM;
priv->mmio = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(priv->mmio))
return PTR_ERR(priv->mmio);
val = readl(priv->mmio + EP93XX_WATCHDOG);
wdd = &priv->wdd;
wdd->bootstatus = (val & 0x01) ? WDIOF_CARDRESET : 0;
wdd->info = &ep93xx_wdt_ident;
wdd->ops = &ep93xx_wdt_ops;
wdd->min_timeout = 1;
wdd->max_hw_heartbeat_ms = 200;
wdd->parent = dev;
watchdog_set_nowayout(wdd, nowayout);
wdd->timeout = WDT_TIMEOUT;
watchdog_init_timeout(wdd, timeout, dev);
watchdog_set_drvdata(wdd, priv);
ret = devm_watchdog_register_device(dev, wdd);
if (ret)
return ret;
dev_info(dev, "EP93XX watchdog driver %s\n",
(val & 0x08) ? " (nCS1 disable detected)" : "");
return 0;
}
static struct platform_driver ep93xx_wdt_driver = {
.driver = {
.name = "ep93xx-wdt",
},
.probe = ep93xx_wdt_probe,
};
module_platform_driver(ep93xx_wdt_driver);
MODULE_AUTHOR("Ray Lehtiniemi <rayl@mail.com>");
MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
MODULE_AUTHOR("H Hartley Sweeten <hsweeten@visionengravers.com>");
MODULE_DESCRIPTION("EP93xx Watchdog");
MODULE_LICENSE("GPL");
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