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

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Message-ID: <2dab5741-fbd0-4af4-b3fe-aa57bf212253@quicinc.com>
Date:   Sat, 4 Nov 2023 04:12:22 +0530
From:   Bibek Kumar Patro <quic_bibekkum@...cinc.com>
To:     Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
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 11/4/2023 3:53 AM, Dmitry Baryshkov wrote:
> 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.
> 

Ack, thanks for pointing this out. Will fix this indentation for loop in
next iteration.

>>
>>>> +
>>>> +       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
>>>>
>>>
>>>
> 
> 
>