linux-kernel - Re: [PATCH v7 3/5] iommu/arm-smmu: introduction of ACTLR for custom prefetcher settings

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Message-ID: <CAA8EJpqO2vEQP3B3gpGHvMSiaMQspz+63WVVXbkd0Hrx-AFeCQ@mail.gmail.com>
Date: Fri, 12 Jan 2024 15:14:46 +0200
From: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To: Bibek Kumar Patro <quic_bibekkum@...cinc.com>
Cc: Konrad Dybcio <konrad.dybcio@...aro.org>, Pavan Kondeti <quic_pkondeti@...cinc.com>, will@...nel.org, 
	robin.murphy@....com, joro@...tes.org, jsnitsel@...hat.com, 
	quic_bjorande@...cinc.com, mani@...nel.org, quic_eberman@...cinc.com, 
	robdclark@...omium.org, u.kleine-koenig@...gutronix.de, robh@...nel.org, 
	vladimir.oltean@....com, quic_molvera@...cinc.com, 
	linux-arm-msm@...r.kernel.org, linux-arm-kernel@...ts.infradead.org, 
	iommu@...ts.linux.dev, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v7 3/5] iommu/arm-smmu: introduction of ACTLR for custom
 prefetcher settings

On Fri, 12 Jan 2024 at 15:07, Bibek Kumar Patro
<quic_bibekkum@...cinc.com> wrote:
>
>
>
> On 1/12/2024 3:31 PM, Konrad Dybcio wrote:
> >
> >
> > On 1/11/24 19:09, Bibek Kumar Patro wrote:
> >>
> >>
> >> On 1/10/2024 11:26 PM, Konrad Dybcio wrote:
> >>>
> >>>
> >>> On 1/10/24 13:55, Bibek Kumar Patro wrote:
> >>>>
> >>>>
> >>>> On 1/10/2024 4:46 PM, Bibek Kumar Patro wrote:
> >>>>>
> >>>>>
> >>>>> On 1/10/2024 9:36 AM, Pavan Kondeti wrote:
> >>>>
> >>>> [...]
> >>>>
> >>>>>>> @@ -274,6 +321,21 @@ static const struct of_device_id
> >>>>>>> qcom_smmu_client_of_match[] __maybe_unused = {
> >>>>>>>   static int qcom_smmu_init_context(struct arm_smmu_domain
> >>>>>>> *smmu_domain,
> >>>>>>>           struct io_pgtable_cfg *pgtbl_cfg, struct device *dev)
> >>>>>>>   {
> >>>>>>> +    struct arm_smmu_device *smmu = smmu_domain->smmu;
> >>>>>>> +    struct qcom_smmu *qsmmu = to_qcom_smmu(smmu);
> >>>>>>> +    const struct actlr_variant *actlrvar;
> >>>>>>> +    int cbndx = smmu_domain->cfg.cbndx;
> >>>>>>> +
> >>>>>>> +    if (qsmmu->data->actlrvar) {
> >>>>>>> +        actlrvar = qsmmu->data->actlrvar;
> >>>>>>> +        for (; actlrvar->io_start; actlrvar++) {
> >>>>>>> +            if (actlrvar->io_start == smmu->ioaddr) {
> >>>>>>> +                qcom_smmu_set_actlr(dev, smmu, cbndx,
> >>>>>>> actlrvar->actlrcfg);
> >>>>>>> +                break;
> >>>>>>> +            }
> >>>>>>> +        }
> >>>>>>> +    }
> >>>>>>> +
> >>>>>>
> >>>>>> This block and the one in qcom_adreno_smmu_init_context() are exactly
> >>>>>> the same. Possible to do some refactoring?
> >>>>>>
> >>>>>
> >>>>> I will check if this repeated blocks can be accomodated this into
> >>>>> qcom_smmu_set_actlr function if that would be fine.
> >>>>>
> >>>>
> >>>> Also adding to this, this might increase the number of indentation
> >>>> inside qcom_smmu_set_actlr as well, to around 5. So wouldn't this
> >>>> be an issue?
> >>>
> >>> By the way, we can refactor this:
> >>>
> >>> if (qsmmu->data->actlrvar) {
> >>>      actlrvar = qsmmu->data->actlrvar;
> >>>      for (; actlrvar->io_start; actlrvar++) {
> >>>          if (actlrvar->io_start == smmu->ioaddr) {
> >>>              qcom_smmu_set_actlr(dev, smmu, cbndx, actlrvar->actlrcfg);
> >>>              break;
> >>>          }
> >>>      }
> >>> }
> >>>
> >>> into
> >>>
> >>> // add const u8 num_actlrcfgs to struct actrl_variant to
> >>> // save on sentinel space:
> >>> //   sizeof(u8) < sizeof(ptr) + sizeof(resource_size_t)
> >>>
> >>
> >> Git it, Would it be better to add this in struct qcom_smmu_match_data ?
> >
> > Yes, right.
> >
>
> Actually, I noticed now, we can do both the actlr_config (num_actlrcfg
> is used) and actlr_var (num_smmu is used) in the similar by storing the
> number of elements in each of them.
> something like this:
>
> +static const struct actlr_config sc7280_apps_actlr_cfg[] = {
> +       { 0x0800, 0x24e1, PREFETCH_DEFAULT | CMTLB },
> +       { 0x2000, 0x0163, PREFETCH_DEFAULT | CMTLB },
> +       { 0x2080, 0x0461, PREFETCH_DEFAULT | CMTLB },
> +       { 0x2100, 0x0161, PREFETCH_DEFAULT | CMTLB },
> +       { 0x0900, 0x0407, PREFETCH_SHALLOW | CPRE | CMTLB },
> +       { 0x2180, 0x0027, PREFETCH_SHALLOW | CPRE | CMTLB },
> +       { 0x1000, 0x07ff, PREFETCH_DEEP | CPRE | CMTLB },
> +};
> +
> +static const struct actlr_config sc7280_gfx_actlr_cfg[] = {
> +       { 0x0000, 0x07ff, PREFETCH_SWITCH_GFX | PREFETCH_DEEP | CPRE | CMTLB },
> +};
> +
> +static const struct actlr_variant sc7280_actlr[] = {
> +       { .io_start = 0x15000000, .actlrcfg = sc7280_apps_actlr_cfg,
> .num_actlrcfg = 7 },
> +       { .io_start = 0x03da0000, .actlrcfg = sc7280_gfx_actlr_cfg,
> .num_actlrcfg = 1 },
> +};
> +
>   static const struct actlr_config sm8550_apps_actlr_cfg[] = {
>         { 0x18a0, 0x0000, PREFETCH_SHALLOW | CPRE | CMTLB },
>         { 0x18e0, 0x0000, PREFETCH_SHALLOW | CPRE | CMTLB },
> @@ -661,6 +680,13 @@ static const struct qcom_smmu_match_data
> sdm845_smmu_500_data = {
>         /* Also no debug configuration. */
>   };
>
> +static const struct qcom_smmu_match_data sc7280_smmu_500_impl0_data = {
> +       .impl = &qcom_smmu_500_impl,
> +       .adreno_impl = &qcom_adreno_smmu_500_impl,
> +       .cfg = &qcom_smmu_impl0_cfg,
> +       .actlrvar = sc7280_actlr,
> +       .num_smmu = 2,
> +};
>
> Just for note , there's a small hiccup here as we have to manually
> calculate and the number of elements in actlr_config size everytime we
> add this info for a new target, won't be an issue though but just a
> hindrance to automation (?)

Just use ARRAY_SIZE(sc7280_actlr).


-- 
With best wishes
Dmitry