Re: [PATCH 3/5] watchdog: sp805: set WDOG_HW_RUNNING when appropriate

[Ray Jui]

Hi Guenter,

On 5/22/2018 1:54 PM, Guenter Roeck wrote:
> On Tue, May 22, 2018 at 11:47:18AM -0700, Ray Jui wrote:
> > If the watchdog hardware is already enabled during the boot process,
> > when the Linux watchdog driver loads, it should reset the watchdog and
> > tell the watchdog framework. As a result, ping can be generated from
> > the watchdog framework, until the userspace watchdog daemon takes over
> > control
> >
> > Signed-off-by: Ray Jui <ray.jui@xxxxxxxxxxxx>
> > Reviewed-by: Vladimir Olovyannikov <vladimir.olovyannikov@xxxxxxxxxxxx>
> > Reviewed-by: Scott Branden <scott.branden@xxxxxxxxxxxx>
> > ---
> >   drivers/watchdog/sp805_wdt.c | 22 ++++++++++++++++++++++
> >   1 file changed, 22 insertions(+)
> >
> > diff --git a/drivers/watchdog/sp805_wdt.c b/drivers/watchdog/sp805_wdt.c
> > index 1484609..408ffbe 100644
> > --- a/drivers/watchdog/sp805_wdt.c
> > +++ b/drivers/watchdog/sp805_wdt.c
> > @@ -42,6 +42,7 @@
> >   	/* control register masks */
> >   	#define	INT_ENABLE	(1 << 0)
> >   	#define	RESET_ENABLE	(1 << 1)
> > +	#define	ENABLE_MASK	(INT_ENABLE | RESET_ENABLE)
> >   #define WDTINTCLR		0x00C
> >   #define WDTRIS			0x010
> >   #define WDTMIS			0x014
> > @@ -74,6 +75,18 @@ module_param(nowayout, bool, 0);
> >   MODULE_PARM_DESC(nowayout,
> >   		"Set to 1 to keep watchdog running after device release");
> >   
> > +/* returns true if wdt is running; otherwise returns false */
> > +static bool wdt_is_running(struct watchdog_device *wdd)
> > +{
> > +	struct sp805_wdt *wdt = watchdog_get_drvdata(wdd);
> > +
> > +	if ((readl_relaxed(wdt->base + WDTCONTROL) & ENABLE_MASK) ==
> > +	    ENABLE_MASK)
> > +		return true;
> > +	else
> > +		return false;
>
> 	return !!(readl_relaxed(wdt->base + WDTCONTROL) & ENABLE_MASK));

Note ENABLE_MASK contains two bits (INT_ENABLE and RESET_ENABLE); 
therefore, a simple !!(expression) would not work? That is, the masked 
result needs to be compared against the mask again to ensure both bits 
are set, right?

Thanks,

Ray