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watchdog: ep93xx_wdt: cleanup and let the core handle the heartbeat
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Cleanup this driver and remove the 200ms heartbeat timer. The core now
has the ability to handle the heartbeat.

Signed-off-by: H Hartley Sweeten <[email protected]>
[groeck: Dropped 0-initialization of static variable]
Signed-off-by: Guenter Roeck <[email protected]>
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@bigguiness @groeck
bigguiness authored and groeck committed Feb 24, 2017
1 parent 8751f90 commit 9170036
Showing 1 changed file with 44 additions and 70 deletions.
114 changes: 44 additions & 70 deletions drivers/watchdog/ep93xx_wdt.c
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Original file line number Diff line number Diff line change
Expand Up @@ -19,81 +19,62 @@
* 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.
*
* TODO:
*
* - Test last reset from watchdog status
* - Add a few missing ioctls
*/

#include <linux/platform_device.h>
#include <linux/module.h>
#include <linux/watchdog.h>
#include <linux/timer.h>
#include <linux/io.h>

#define WDT_VERSION "0.4"

/* 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 = WDT_TIMEOUT;
static unsigned int timeout;
module_param(timeout, uint, 0);
MODULE_PARM_DESC(timeout,
"Watchdog timeout in seconds. (1<=timeout<=3600, default="
__MODULE_STRING(WDT_TIMEOUT) ")");

static void __iomem *mmio_base;
static struct timer_list timer;
static unsigned long next_heartbeat;
MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds.");

#define EP93XX_WATCHDOG 0x00
#define EP93XX_WDSTATUS 0x04

/* reset the wdt every ~200ms - the heartbeat of the device is 0.250 seconds*/
#define WDT_INTERVAL (HZ/5)

static void ep93xx_wdt_timer_ping(unsigned long data)
{
if (time_before(jiffies, next_heartbeat))
writel(0x5555, mmio_base + EP93XX_WATCHDOG);

/* Re-set the timer interval */
mod_timer(&timer, jiffies + WDT_INTERVAL);
}
struct ep93xx_wdt_priv {
void __iomem *mmio;
struct watchdog_device wdd;
};

static int ep93xx_wdt_start(struct watchdog_device *wdd)
{
next_heartbeat = jiffies + (timeout * HZ);
struct ep93xx_wdt_priv *priv = watchdog_get_drvdata(wdd);

writel(0xaaaa, mmio_base + EP93XX_WATCHDOG);
mod_timer(&timer, jiffies + WDT_INTERVAL);
writel(0xaaaa, priv->mmio + EP93XX_WATCHDOG);

return 0;
}

static int ep93xx_wdt_stop(struct watchdog_device *wdd)
{
del_timer_sync(&timer);
writel(0xaa55, mmio_base + EP93XX_WATCHDOG);
struct ep93xx_wdt_priv *priv = watchdog_get_drvdata(wdd);

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

return 0;
}

static int ep93xx_wdt_keepalive(struct watchdog_device *wdd)
static int ep93xx_wdt_ping(struct watchdog_device *wdd)
{
/* user land ping */
next_heartbeat = jiffies + (timeout * HZ);
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",
Expand All @@ -103,55 +84,50 @@ static const struct watchdog_ops ep93xx_wdt_ops = {
.owner = THIS_MODULE,
.start = ep93xx_wdt_start,
.stop = ep93xx_wdt_stop,
.ping = ep93xx_wdt_keepalive,
};

static struct watchdog_device ep93xx_wdt_wdd = {
.info = &ep93xx_wdt_ident,
.ops = &ep93xx_wdt_ops,
.ping = ep93xx_wdt_ping,
};

static int ep93xx_wdt_probe(struct platform_device *pdev)
{
struct ep93xx_wdt_priv *priv;
struct watchdog_device *wdd;
struct resource *res;
unsigned long val;
int err;
int ret;

priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
if (!priv)
return -ENOMEM;

res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
mmio_base = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(mmio_base))
return PTR_ERR(mmio_base);
priv->mmio = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(priv->mmio))
return PTR_ERR(priv->mmio);

if (timeout < 1 || timeout > 3600) {
timeout = WDT_TIMEOUT;
dev_warn(&pdev->dev,
"timeout value must be 1<=x<=3600, using %d\n",
timeout);
}
val = readl(priv->mmio + EP93XX_WATCHDOG);

val = readl(mmio_base + EP93XX_WATCHDOG);
ep93xx_wdt_wdd.bootstatus = (val & 0x01) ? WDIOF_CARDRESET : 0;
ep93xx_wdt_wdd.timeout = timeout;
ep93xx_wdt_wdd.parent = &pdev->dev;
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 = &pdev->dev;

watchdog_set_nowayout(&ep93xx_wdt_wdd, nowayout);
watchdog_set_nowayout(wdd, nowayout);

setup_timer(&timer, ep93xx_wdt_timer_ping, 1);
wdd->timeout = WDT_TIMEOUT;
watchdog_init_timeout(wdd, timeout, &pdev->dev);

err = watchdog_register_device(&ep93xx_wdt_wdd);
if (err)
return err;
watchdog_set_drvdata(wdd, priv);

dev_info(&pdev->dev,
"EP93XX watchdog, driver version " WDT_VERSION "%s\n",
(val & 0x08) ? " (nCS1 disable detected)" : "");
ret = devm_watchdog_register_device(&pdev->dev, wdd);
if (ret)
return ret;

return 0;
}
dev_info(&pdev->dev, "EP93XX watchdog driver %s\n",
(val & 0x08) ? " (nCS1 disable detected)" : "");

static int ep93xx_wdt_remove(struct platform_device *pdev)
{
watchdog_unregister_device(&ep93xx_wdt_wdd);
return 0;
}

Expand All @@ -160,7 +136,6 @@ static struct platform_driver ep93xx_wdt_driver = {
.name = "ep93xx-wdt",
},
.probe = ep93xx_wdt_probe,
.remove = ep93xx_wdt_remove,
};

module_platform_driver(ep93xx_wdt_driver);
Expand All @@ -170,4 +145,3 @@ MODULE_AUTHOR("Alessandro Zummo <[email protected]>");
MODULE_AUTHOR("H Hartley Sweeten <[email protected]>");
MODULE_DESCRIPTION("EP93xx Watchdog");
MODULE_LICENSE("GPL");
MODULE_VERSION(WDT_VERSION);

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