[PATCH 3/5] perf/arm_cspmu: Simplify counter reset

[Ilkka Koskinen]

On Tue, 5 Dec 2023, Robin Murphy wrote:
> arm_cspmu_reset_counters() inherently also stops them since it is
> writing 0 to PMCR.E, so there should be no need to do that twice.
> Also tidy up the reset routine itself for consistency with the start
> and stop routines, and to be clear at first glance that it is simply
> writing a constant value.
>
> Signed-off-by: Robin Murphy <robin.murphy at arm.com>


Reviewed-by: Ilkka Koskinen <ilkka at os.amperecomputing.com>

Cheers, Ilkka


> ---
> drivers/perf/arm_cspmu/arm_cspmu.c | 7 +------
> 1 file changed, 1 insertion(+), 6 deletions(-)
>
> diff --git a/drivers/perf/arm_cspmu/arm_cspmu.c b/drivers/perf/arm_cspmu/arm_cspmu.c
> index f7aa2ac5fd88..b64de4d800c7 100644
> --- a/drivers/perf/arm_cspmu/arm_cspmu.c
> +++ b/drivers/perf/arm_cspmu/arm_cspmu.c
> @@ -525,11 +525,7 @@ static int arm_cspmu_alloc_attr_groups(struct arm_cspmu *cspmu)
>
> static inline void arm_cspmu_reset_counters(struct arm_cspmu *cspmu)
> {
> -	u32 pmcr = 0;
> -
> -	pmcr |= PMCR_P;
> -	pmcr |= PMCR_C;
> -	writel(pmcr, cspmu->base0 + PMCR);
> +	writel(PMCR_C | PMCR_P, cspmu->base0 + PMCR);
> }
>
> static inline void arm_cspmu_start_counters(struct arm_cspmu *cspmu)
> @@ -1189,7 +1185,6 @@ static int arm_cspmu_register_pmu(struct arm_cspmu *cspmu)
> 	};
>
> 	/* Hardware counter init */
> -	arm_cspmu_stop_counters(cspmu);
> 	arm_cspmu_reset_counters(cspmu);
>
> 	ret = perf_pmu_register(&cspmu->pmu, cspmu->name, -1);
> -- 
> 2.39.2.101.g768bb238c484.dirty
>
>