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To:     Vivek Gautam <vivek.gautam@codeaurora.org>, agross@kernel.org,
        iommu@lists.linux-foundation.org, joro@8bytes.org,
        robin.murphy@arm.com, will.deacon@arm.com
From:   Stephen Boyd <swboyd@chromium.org>
Cc:     bjorn.andersson@linaro.org, linux-arm-msm@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        Vivek Gautam <vivek.gautam@codeaurora.org>
Subject: Re: [PATCH v4 3/3] iommu: arm-smmu-impl: Add sdm845 implementation hook
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Date:   Fri, 06 Sep 2019 08:07:07 -0700
Sender: linux-kernel-owner@vger.kernel.org
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Quoting Vivek Gautam (2019-08-22 23:32:48)
> diff --git a/drivers/iommu/arm-smmu-impl.c b/drivers/iommu/arm-smmu-impl.c
> index 3f88cd078dd5..0aef87c41f9c 100644
> --- a/drivers/iommu/arm-smmu-impl.c
> +++ b/drivers/iommu/arm-smmu-impl.c
> @@ -102,7 +103,6 @@ static struct arm_smmu_device *cavium_smmu_impl_init(=
struct arm_smmu_device *smm
>         return &cs->smmu;
>  }
> =20
> -
>  #define ARM_MMU500_ACTLR_CPRE          (1 << 1)
> =20
>  #define ARM_MMU500_ACR_CACHE_LOCK      (1 << 26)

Drop this hunk?=20

> @@ -147,6 +147,28 @@ static const struct arm_smmu_impl arm_mmu500_impl =
=3D {
>         .reset =3D arm_mmu500_reset,
>  };
> =20
> +static int qcom_sdm845_smmu500_reset(struct arm_smmu_device *smmu)
> +{
> +       int ret;
> +
> +       arm_mmu500_reset(smmu);
> +
> +       /*
> +        * To address performance degradation in non-real time clients,
> +        * such as USB and UFS, turn off wait-for-safe on sdm845 based bo=
ards,
> +        * such as MTP and db845, whose firmwares implement secure monitor
> +        * call handlers to turn on/off the wait-for-safe logic.
> +        */
> +       ret =3D qcom_scm_qsmmu500_wait_safe_toggle(0);
> +       if (ret)
> +               dev_warn(smmu->dev, "Failed to turn off SAFE logic\n");
> +
> +       return 0;

return ret? Or intentionally don't return an error for failure?

> +}
> +
> +const struct arm_smmu_impl qcom_sdm845_smmu500_impl =3D {

static?

> +       .reset =3D qcom_sdm845_smmu500_reset,
> +};
> =20
>  struct arm_smmu_device *arm_smmu_impl_init(struct arm_smmu_device *smmu)
>  {