Messages in this thread | | | Subject | Re: [PATCH 3/5] watchdog: sp805: set WDOG_HW_RUNNING when appropriate | From | Ray Jui <> | Date | Wed, 23 May 2018 09:29:23 -0700 |
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Hi Robin,
On 5/23/2018 4:48 AM, Robin Murphy wrote: > On 23/05/18 08:52, Scott Branden wrote: >> >> >> On 18-05-22 04:24 PM, Ray Jui wrote: >>> 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@broadcom.com> >>>>> Reviewed-by: Vladimir Olovyannikov >>>>> <vladimir.olovyannikov@broadcom.com> >>>>> Reviewed-by: Scott Branden <scott.branden@broadcom.com> >>>>> --- >>>>> 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? >> Ray - your original code looks correct to me. Easier to read and less >> prone to errors as shown in the attempted translation to a single >> statement. > > if (<boolean condition>) > return true; > else > return false; > > still looks really dumb, though, and IMO is actually harder to read than > just "return <boolean condition>;" because it forces you to stop and > double-check that the logic is, in fact, only doing the obvious thing.
If you can propose a way to modify my original code above to make it more readable, I'm fine to make the change.
As I mentioned, I don't think the following change proposed by Guenter will work due to the reason I pointed out:
return !!(readl_relaxed(wdt->base + WDTCONTROL) & ENABLE_MASK));
> > Robin. > > > > p.s. No thanks for making me remember the mind-boggling horror of > briefly maintaining part of this legacy codebase... :P > > $ grep -r '? true : false' --include=*.cpp . | wc -l > 951
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