Re: [PATCH 09/20] clocksource/drivers/vf-pit: Register the clocksource from the driver

[Daniel Lezcano]

On 07/07/2025 14:02, Ghennadi Procopciuc wrote:
> On 7/5/2025 7:01 PM, Daniel Lezcano wrote:
> [...]
>
> > +static u64 pit_timer_clocksource_read(struct clocksource *cs)
> > +{
> > +	struct pit_timer *pit = cs_to_pit(cs);
> > +
> > +	return ~(u64)readl(pit->clksrc_base + PITCVAL);
> > +}
>
> The CVAL register is a 32-bit countdown timer. Casting its value to 64 bits before applying bitwise negation results in a 64-bit value where the upper 32 bits are always set. To avoid this, shouldn't the operations be reordered so that the bitwise negation is applied first to the 32-bit value, followed by casting the result to 64 bits?

Yes, that's right

Good catch !

Thanks



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