From: Ilkka Koskinen <ilkka@os.amperecomputing.com>
To: Robin Murphy <robin.murphy@arm.com>
Cc: will@kernel.org, mark.rutland@arm.com,
linux-arm-kernel@lists.infradead.org,
devicetree@vger.kernel.org, suzuki.poulose@arm.com,
ilkka@os.amperecomputing.com, bwicaksono@nvidia.com,
YWan@nvidia.com, rwiley@nvidia.com
Subject: Re: [PATCH 3/5] perf/arm_cspmu: Simplify counter reset
Date: Wed, 6 Dec 2023 18:15:45 -0800 (PST) [thread overview]
Message-ID: <b5d7abb5-443c-f66c-901d-232d2ff3264b@os.amperecomputing.com> (raw)
In-Reply-To: <34ecf45f0f9a0fa34a580f162f02c23d9b849d90.1701793996.git.robin.murphy@arm.com>
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@arm.com>
Reviewed-by: Ilkka Koskinen <ilkka@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
>
>
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next prev parent reply other threads:[~2023-12-07 2:16 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-12-05 16:51 [PATCH 0/5] perf/arm_cspmu: Add devicetree support Robin Murphy
2023-12-05 16:51 ` [PATCH 1/5] perf/arm_cspmu: Simplify initialisation Robin Murphy
2023-12-07 2:16 ` Ilkka Koskinen
2023-12-05 16:51 ` [PATCH 2/5] perf/arm_cspmu: Simplify attribute groups Robin Murphy
2023-12-07 2:47 ` Ilkka Koskinen
2023-12-05 16:51 ` [PATCH 3/5] perf/arm_cspmu: Simplify counter reset Robin Murphy
2023-12-07 2:15 ` Ilkka Koskinen [this message]
2023-12-05 16:51 ` [PATCH 4/5] dt-bindings/perf: Add Arm CoreSight PMU Robin Murphy
2023-12-08 19:33 ` Rob Herring
2023-12-08 21:56 ` Robin Murphy
2023-12-05 16:51 ` [PATCH 5/5] perf/arm_cspmu: Add devicetree support Robin Murphy
2023-12-06 23:43 ` Ilkka Koskinen
2023-12-07 9:43 ` Robin Murphy
2023-12-08 6:35 ` Ilkka Koskinen
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