[PATCH v2 1/1] watchdog: mtk_wdt: Remove mtk_wdt_stop() in probe() to prevent the system freeze and it doesn't reboot by watchdog problem

[Freddy.Hsin]

On Thu, 2020-12-31 at 00:50 +0800, Guenter Roeck wrote:
> On 12/30/20 12:15 AM, Freddy Hsin wrote:
> > From: "freddy.hsin" <freddy.hsin at mediatek.com>
> > 
> > Before user space daemon start to access the watchdog device,
> > there is a time interval that watchdog is disabled in the
> > original flow. If the system freezing at this interval, it
> > cannot be rebooted by watchdog hardware automatically.
> > 
> > In order to solve this problem, the watchdog hardware should be
> > kept working, and start hrtimer in framework to ping it by
> > setting max_hw_heartbeat_ms and HW_RUNNING used in
> > watchdog_need_worker to determine whether the worker should be
> > started or not. Besides the redundant setting of max_timeout is
> > also removed.
> > 
> > Signed-off-by: freddy.hsin <freddy.hsin at mediatek.com>
> > ---
> 
> Change log goes here.
> 
> Looks good though.
> 
> Reviewed-by: Guenter Roeck <linux at roeck-us.net>


Dear Sir,

Will this change be merged into the mainline tree?

BRs,
FreddyHsin


> 
> >  drivers/watchdog/mtk_wdt.c |   17 +++++++++++++++--
> >  1 file changed, 15 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/watchdog/mtk_wdt.c b/drivers/watchdog/mtk_wdt.c
> > index d6a6393..0c869b7 100644
> > --- a/drivers/watchdog/mtk_wdt.c
> > +++ b/drivers/watchdog/mtk_wdt.c
> > @@ -195,6 +195,19 @@ static int mtk_wdt_set_timeout(struct watchdog_device *wdt_dev,
> >  	return 0;
> >  }
> >  
> > +static void mtk_wdt_init(struct watchdog_device *wdt_dev)
> > +{
> > +	struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev);
> > +	void __iomem *wdt_base;
> > +
> > +	wdt_base = mtk_wdt->wdt_base;
> > +
> > +	if (readl(wdt_base + WDT_MODE) & WDT_MODE_EN) {
> > +		set_bit(WDOG_HW_RUNNING, &wdt_dev->status);
> > +		mtk_wdt_set_timeout(wdt_dev, wdt_dev->timeout);
> > +	}
> > +}
> > +
> >  static int mtk_wdt_stop(struct watchdog_device *wdt_dev)
> >  {
> >  	struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev);
> > @@ -264,7 +277,7 @@ static int mtk_wdt_probe(struct platform_device *pdev)
> >  	mtk_wdt->wdt_dev.info = &mtk_wdt_info;
> >  	mtk_wdt->wdt_dev.ops = &mtk_wdt_ops;
> >  	mtk_wdt->wdt_dev.timeout = WDT_MAX_TIMEOUT;
> > -	mtk_wdt->wdt_dev.max_timeout = WDT_MAX_TIMEOUT;
> > +	mtk_wdt->wdt_dev.max_hw_heartbeat_ms = WDT_MAX_TIMEOUT * 1000;
> >  	mtk_wdt->wdt_dev.min_timeout = WDT_MIN_TIMEOUT;
> >  	mtk_wdt->wdt_dev.parent = dev;
> >  
> > @@ -274,7 +287,7 @@ static int mtk_wdt_probe(struct platform_device *pdev)
> >  
> >  	watchdog_set_drvdata(&mtk_wdt->wdt_dev, mtk_wdt);
> >  
> > -	mtk_wdt_stop(&mtk_wdt->wdt_dev);
> > +	mtk_wdt_init(&mtk_wdt->wdt_dev);
> >  
> >  	watchdog_stop_on_reboot(&mtk_wdt->wdt_dev);
> >  	err = devm_watchdog_register_device(dev, &mtk_wdt->wdt_dev);
> > 
>