Re: [PATCH] perf/smmuv3: Use platform_get_irq_optional() for wired interrupt

[Robin Murphy <robin.murphy@arm.com>]

On 10/02/2020 4:50 pm, John Garry wrote:
> Even though a SMMUv3 PMCG implementation may use an MSI as the form of
> interrupt source, the kernel would still complain that it does not find
> the wired (GSIV) interrupt in this case:
> 
> root@(none)$ dmesg | grep arm-smmu-v3-pmcg | grep "not found"
> [   59.237219] arm-smmu-v3-pmcg arm-smmu-v3-pmcg.8.auto: IRQ index 0 not found
> [   59.322841] arm-smmu-v3-pmcg arm-smmu-v3-pmcg.9.auto: IRQ index 0 not found
> [   59.422155] arm-smmu-v3-pmcg arm-smmu-v3-pmcg.10.auto: IRQ index 0 not found
> [   59.539014] arm-smmu-v3-pmcg arm-smmu-v3-pmcg.11.auto: IRQ index 0 not found
> [   59.640329] arm-smmu-v3-pmcg arm-smmu-v3-pmcg.12.auto: IRQ index 0 not found
> [   59.743112] arm-smmu-v3-pmcg arm-smmu-v3-pmcg.13.auto: IRQ index 0 not found
> [   59.880577] arm-smmu-v3-pmcg arm-smmu-v3-pmcg.14.auto: IRQ index 0 not found
> [   60.017528] arm-smmu-v3-pmcg arm-smmu-v3-pmcg.15.auto: IRQ index 0 not found
> 
> Use platform_get_irq_optional() to silence the warning.
> 
> If neither interrupt source is found, then the driver will still warn that
> IRQ setup errored and the probe will fail.

Indeed, this is fallout from the core platform_get_irq() changes, but is 
clearly appropriate since the GSIV is explicitly optional in IORT. Not 
to mention we did the same thing for SMMUv3 itself already.

Reviewed-by: Robin Murphy <robin.murphy@arm.com>

> Signed-off-by: John Garry <john.garry@huawei.com>
> 
> diff --git a/drivers/perf/arm_smmuv3_pmu.c b/drivers/perf/arm_smmuv3_pmu.c
> index d704eccc548f..f01a57e5a5f3 100644
> --- a/drivers/perf/arm_smmuv3_pmu.c
> +++ b/drivers/perf/arm_smmuv3_pmu.c
> @@ -771,7 +771,7 @@ static int smmu_pmu_probe(struct platform_device *pdev)
>   		smmu_pmu->reloc_base = smmu_pmu->reg_base;
>   	}
>   
> -	irq = platform_get_irq(pdev, 0);
> +	irq = platform_get_irq_optional(pdev, 0);
>   	if (irq > 0)
>   		smmu_pmu->irq = irq;
>   
>