Re: [PATCH V5 2/7] clocksource: tegra: add Tegra210 timer support

[Joseph Lo]

On 2/1/19 11:43 PM, Jon Hunter wrote:
> On 01/02/2019 14:39, Joseph Lo wrote:
> > On 2/1/19 8:44 PM, Jon Hunter wrote:
> > > On 01/02/2019 03:36, Joseph Lo wrote:
> > > > Add support for the Tegra210 timer that runs at oscillator clock
> > > > (TMR10-TMR13). We need these timers to work as clock event device and to
> > > > replace the ARMv8 architected timer due to it can't survive across the
> > > > power cycle of the CPU core or CPUPORESET signal. So it can't be a
> > > > wake-up
> > > > source when CPU suspends in power down state.
> > > >
> > > > Also convert the original driver to use timer-of API.
> > >
> > > It may have been nice to split this into 2 patches to make it easier to
> > > see what is going on but not a big deal.
> > >
> > > > Cc: Daniel Lezcano <daniel.lezcano@xxxxxxxxxx>
> > > > Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> > > > Cc: linux-kernel@xxxxxxxxxxxxxxx
> > > > Signed-off-by: Joseph Lo <josephl@xxxxxxxxxx>
> > > > Acked-by: Thierry Reding <treding@xxxxxxxxxx>
> > > > ---
snip.
> > >
> > This can't get the timer base address. I think you mean ...
> >
> > +#ifdef CONFIG_ARM
> > +#define TIMER_CPU0 0x50 /* TIMER3 */
> > +#else
> > +#define TIMER_CPU0 0x90 /* TIMER10 */
> > +#endif
> > +#define TIMER_BASE_FOR_CPU(cpu) (TIMER_CPU0 + (cpu) * 8)
>
> Ah I see.
>
> > This doesn't need.
> > +#define TIMER_FOR_CPU(cpu) (TIMER_CPU0 + cpu)
> How come? Don't you still need to know the timer index for a given CPU?

Doesn't need. TIMER_BASE_FOR_CPU is enough. Other use cases are well 
handled by timer-of API. :)

Thanks,
Joseph