linux-kernel - Re: [PATCH 1/1] iommu/arm-smmu-qcom: remove runtime pm enabling for TBU driver

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Message-ID: <ZroNUGkKuC1L7Qfr@google.com>
Date: Mon, 12 Aug 2024 13:25:36 +0000
From: Pranjal Shrivastava <praan@...gle.com>
To: Zhenhua Huang <quic_zhenhuah@...cinc.com>
Cc: robdclark@...il.com, will@...nel.org, robin.murphy@....com,
	joro@...tes.org, iommu@...ts.linux.dev,
	linux-arm-msm@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org, quic_c_gdjako@...cinc.com,
	dmitry.baryshkov@...aro.org
Subject: Re: [PATCH 1/1] iommu/arm-smmu-qcom: remove runtime pm enabling for
 TBU driver

On Tue, Jul 30, 2024 at 06:30:43PM +0800, Zhenhua Huang wrote:
> TBU driver has no runtime pm support now, adding pm_runtime_enable()
> seems to be useless. Remove it.
> 
> Signed-off-by: Zhenhua Huang <quic_zhenhuah@...cinc.com>
> ---
>  drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c | 6 ------
>  1 file changed, 6 deletions(-)
> 
> diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
> index 36c6b36ad4ff..aff2fe1fda13 100644
> --- a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
> +++ b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
> @@ -566,7 +566,6 @@ static struct acpi_platform_list qcom_acpi_platlist[] = {
>  
>  static int qcom_smmu_tbu_probe(struct platform_device *pdev)
>  {
> -	struct device *dev = &pdev->dev;
>  	int ret;
>  
>  	if (IS_ENABLED(CONFIG_ARM_SMMU_QCOM_DEBUG)) {
> @@ -575,11 +574,6 @@ static int qcom_smmu_tbu_probe(struct platform_device *pdev)
>  			return ret;
>  	}
>  
> -	if (dev->pm_domain) {
> -		pm_runtime_set_active(dev);
> -		pm_runtime_enable(dev);

I assumed that this was required to avoid the TBU from being powered
down? If so, then I think we shall move it under the
previous if condition, i.e. CONFIG_ARM_SMMU_QCOM_DEBUG?

If not, we can remove it give that the TBU would be powered ON as needed

> -	}
> -
>  	return 0;
>  }
>  
> -- 
> 2.7.4
> 
> 

Thanks,
Pranjal