linux-kernel - Re: [PATCH 3/3] iommu/arm-smmu: re-enable context caching in smmu reset operation

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Message-ID: <CAA8EJprG_=p=F7BCUG6gBwHAP3VHQxYnx91fYSOKwBV_nJ3HAw@mail.gmail.com>
Date:   Sat, 4 Nov 2023 00:23:07 +0200
From:   Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To:     Bibek Kumar Patro <quic_bibekkum@...cinc.com>
Cc:     will@...nel.org, robin.murphy@....com, joro@...tes.org,
        a39.skl@...il.com, konrad.dybcio@...aro.org,
        quic_saipraka@...cinc.com, quic_pkondeti@...cinc.com,
        quic_molvera@...cinc.com, linux-arm-kernel@...ts.infradead.org,
        iommu@...ts.linux.dev, linux-kernel@...r.kernel.org,
        qipl.kernel.upstream@...cinc.com
Subject: Re: [PATCH 3/3] iommu/arm-smmu: re-enable context caching in smmu
 reset operation

On Sat, 4 Nov 2023 at 00:07, Bibek Kumar Patro
<quic_bibekkum@...cinc.com> wrote:
>
>
>
> On 11/4/2023 3:28 AM, Dmitry Baryshkov wrote:
> > On Fri, 3 Nov 2023 at 23:53, Bibek Kumar Patro
> > <quic_bibekkum@...cinc.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@...cinc.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?
> >
>
> Yes Dmitry, I did run checkpatch.pl script on this patch as well as
> others, got 0 errors and 0 warnings. With -f option as well. Did not
> get any related errors and warnings.

Ack, I beg your pardon. checkpatch indeed doesn't warn about this
indentation. Though it is still incorrect.

>
> >> +
> >> +       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