Re: [PATCH v5 07/11] arm-cci: Add routines to save/restore all counters

[Suzuki K. Poulose]

On 11/01/16 10:50, Mark Rutland wrote:
> On Mon, Jan 04, 2016 at 11:54:46AM +0000, Suzuki K. Poulose wrote:
> > Adds helper routines to disable the counter controls for
> > all the counters on the CCI PMU and restore it back, by
> > preserving the original state in caller provided mask.
> >
> > Cc: Punit Agrawal <punit.agrawal@xxxxxxx>
> > Cc: Mark Rutland <mark.rutland@xxxxxxx>
> > Signed-off-by: Suzuki K. Poulose <suzuki.poulose@xxxxxxx>
> > ---
> >   drivers/bus/arm-cci.c |   38 ++++++++++++++++++++++++++++++++++++++
> >   1 file changed, 38 insertions(+)
> >
> > diff --git a/drivers/bus/arm-cci.c b/drivers/bus/arm-cci.c
> > index a3938ef..2f1fcf0 100644
> > --- a/drivers/bus/arm-cci.c
> > +++ b/drivers/bus/arm-cci.c
> > @@ -672,6 +672,44 @@ static void pmu_set_event(struct cci_pmu *cci_pmu, int idx, unsigned long event)
> >   }
> >
> >   /*
> > + * For all counters on the CCI-PMU, disable any 'enabled' counters,
> > + * saving the changed counters in the mask, so that we can restore
> > + * it later using pmu_restore_counters. The mask is private to the
> > + * caller. We cannot rely on the used_mask maintained by the CCI_PMU
> > + * as it only tells us if the counter is assigned to perf_event or not.
> > + * The state of the perf_event cannot be locked by the PMU layer, hence
> > + * we check the individual counter status (which can be locked by
> > + * cci_pm->hw_events->pmu_lock).
> > + *
> > + * @mask should be initialised by the caller.
>
> We should probably state "initialised to zero", or "empty".

Yep, will fix it.

> > +/*
> > + * Restore the status of the counters. Reversal of the pmu_disable_counters().
> > + * For each counter set in the mask, enable the counter back.
> > + */
>
> Shouldn't that say pmu_save_counters?

Yea, missed it in rebase.

> With that:
>
> Acked-by: Mark Rutland <mark.rutland@xxxxxxx>

Thanks
Suzuki