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References: <20231103215124.1095-1-quic_bibekkum@quicinc.com> <20231103215124.1095-4-quic_bibekkum@quicinc.com>
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From:   Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Date:   Fri, 3 Nov 2023 23:58:10 +0200
Message-ID: <CAA8EJpob0DoXd_UTEiJf8z3JncaWk_1rgit6c4dqQ0gB6JDFxQ@mail.gmail.com>
Subject: Re: [PATCH 3/3] iommu/arm-smmu: re-enable context caching in smmu
 reset operation
To:     Bibek Kumar Patro <quic_bibekkum@quicinc.com>
Cc:     will@kernel.org, robin.murphy@arm.com, joro@8bytes.org,
        a39.skl@gmail.com, konrad.dybcio@linaro.org,
        quic_saipraka@quicinc.com, quic_pkondeti@quicinc.com,
        quic_molvera@quicinc.com, linux-arm-kernel@lists.infradead.org,
        iommu@lists.linux.dev, linux-kernel@vger.kernel.org,
        qipl.kernel.upstream@quicinc.com
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On Fri, 3 Nov 2023 at 23:53, Bibek Kumar Patro
<quic_bibekkum@quicinc.com> wrote:
>
> Context caching is re-enabled in the prefetch buffer for Qualcomm SoCs
> through SoC specific reset ops, which is disabled in the default MMU-500
> reset ops, but is expected for context banks using ACTLR register to
> retain the prefetch value during reset and runtime suspend.
>
> Signed-off-by: Bibek Kumar Patro <quic_bibekkum@quicinc.com>
> ---
>  drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c | 26 ++++++++++++++++++----
>  1 file changed, 22 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
> index 590b7c285299..f342b4778cf1 100644
> --- a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
> +++ b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
> @@ -457,11 +457,29 @@ static int qcom_smmu_def_domain_type(struct device *dev)
>         return match ? IOMMU_DOMAIN_IDENTITY : 0;
>  }
>
> +#define ARM_MMU500_ACTLR_CPRE          BIT(1)
> +
> +static int qcom_smmu500_reset(struct arm_smmu_device *smmu)
> +{
> +       int i;
> +       u32 reg;
> +
> +       arm_mmu500_reset(smmu);
> +
> +               for (i = 0; i < smmu->num_context_banks; ++i) {
> +                       reg = arm_smmu_cb_read(smmu, i, ARM_SMMU_CB_ACTLR);
> +                       reg |= ARM_MMU500_ACTLR_CPRE;
> +                       arm_smmu_cb_write(smmu, i, ARM_SMMU_CB_ACTLR, reg);
> +               }

Wrong indentation. Did you run your patches through checkpatch.pl?

> +
> +       return 0;
> +}
> +
>  static int qcom_sdm845_smmu500_reset(struct arm_smmu_device *smmu)
>  {
>         int ret;
>
> -       arm_mmu500_reset(smmu);
> +       qcom_smmu500_reset(smmu);
>
>         /*
>          * To address performance degradation in non-real time clients,
> @@ -488,7 +506,7 @@ static const struct arm_smmu_impl qcom_smmu_500_impl = {
>         .init_context = qcom_smmu_init_context,
>         .cfg_probe = qcom_smmu_cfg_probe,
>         .def_domain_type = qcom_smmu_def_domain_type,
> -       .reset = arm_mmu500_reset,
> +       .reset = qcom_smmu500_reset,
>         .write_s2cr = qcom_smmu_write_s2cr,
>         .tlb_sync = qcom_smmu_tlb_sync,
>  };
> @@ -507,7 +525,7 @@ static const struct arm_smmu_impl sm8550_smmu_500_impl = {
>         .init_context = qcom_smmu_init_context,
>         .cfg_probe = qcom_smmu_cfg_probe,
>         .def_domain_type = qcom_smmu_def_domain_type,
> -       .reset = arm_mmu500_reset,
> +       .reset = qcom_smmu500_reset,
>         .write_s2cr = qcom_smmu_write_s2cr,
>         .tlb_sync = qcom_smmu_tlb_sync,
>  };
> @@ -523,7 +541,7 @@ static const struct arm_smmu_impl qcom_adreno_smmu_v2_impl = {
>  static const struct arm_smmu_impl qcom_adreno_smmu_500_impl = {
>         .init_context = qcom_adreno_smmu_init_context,
>         .def_domain_type = qcom_smmu_def_domain_type,
> -       .reset = arm_mmu500_reset,
> +       .reset = qcom_smmu500_reset,
>         .alloc_context_bank = qcom_adreno_smmu_alloc_context_bank,
>         .write_sctlr = qcom_adreno_smmu_write_sctlr,
>         .tlb_sync = qcom_smmu_tlb_sync,
> --
> 2.17.1
>


-- 
With best wishes
Dmitry