2023-11-15 05:43:32

by Bibek Kumar Patro

[permalink] [raw]
Subject: Re: [PATCH v2 1/3] iommu/arm-smmu: introduction of ACTLR for custom prefetcher settings



On 11/14/2023 7:38 PM, Dmitry Baryshkov wrote:
> On Tue, 14 Nov 2023 at 15:57, Bibek Kumar Patro
> <[email protected]> wrote:
>>
>> Currently in Qualcomm SoCs the default prefetch is set to 1 which allows
>> the TLB to fetch just the next page table. MMU-500 features ACTLR
>> register which is implementation defined and is used for Qualcomm SoCs
>> to have a prefetch setting of 1/3/7/15 enabling TLB to prefetch
>> the next set of page tables accordingly allowing for faster translations.
>>
>> ACTLR value is unique for each SMR (Stream matching register) and stored
>> in a pre-populated table. This value is set to the register during
>> context bank initialisation.
>>
>> Signed-off-by: Bibek Kumar Patro <[email protected]>
>> ---
>> drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c | 41 ++++++++++++++++++++++
>> drivers/iommu/arm/arm-smmu/arm-smmu-qcom.h | 2 ++
>> drivers/iommu/arm/arm-smmu/arm-smmu.c | 5 +--
>> drivers/iommu/arm/arm-smmu/arm-smmu.h | 5 +++
>> 4 files changed, 51 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
>> index 549ae4dba3a6..578c662c7c30 100644
>> --- a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
>> +++ b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
>> @@ -14,6 +14,17 @@
>>
>> #define QCOM_DUMMY_VAL -1
>>
>> +struct actlr_config {
>> + const struct actlr_data *adata;
>> + size_t size;
>
> Merge this into struct qcom_smmu_match_data.
>

Just saw your response on the other thread in v1 patch,
let me try again once to accomodate into single structure
as suggested

>> +};
>> +
>> +struct actlr_data {
>> + u16 sid;
>> + u16 mask;
>> + u32 actlr;
>> +};
>> +
>> static struct qcom_smmu *to_qcom_smmu(struct arm_smmu_device *smmu)
>> {
>> return container_of(smmu, struct qcom_smmu, smmu);
>> @@ -261,9 +272,36 @@ static const struct of_device_id qcom_smmu_client_of_match[] __maybe_unused = {
>> { }
>> };
>>
>> +static void arm_smmu_set_actlr(struct arm_smmu_device *smmu, int idx,
>> + const struct actlr_config *actlrcfg)
>> +{
>> + struct arm_smmu_smr *smr = smmu->smrs;
>> + int i;
>> + u16 id;
>> + u16 mask;
>> +
>> + for (i = 0; i < actlrcfg->size; ++i) {
>> + id = actlrcfg->adata[i].sid;
>> + mask = actlrcfg->adata[i].mask;
>> + if (!smr_is_subset(*smr, id, mask))
>> + arm_smmu_cb_write(smmu, idx, ARM_SMMU_CB_ACTLR,
>> + actlrcfg->adata[i].actlr);
>> + }
>> +}
>> +
>> 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_config *actlrcfg;
>> + int idx = smmu_domain->cfg.cbndx;
>> +
>> + if (qsmmu->actlrcfg) {
>> + actlrcfg = qsmmu->actlrcfg;
>> + arm_smmu_set_actlr(smmu, idx, actlrcfg);
>> + }
>> +
>> smmu_domain->cfg.flush_walk_prefer_tlbiasid = true;
>>
>> return 0;
>> @@ -467,6 +505,9 @@ static struct arm_smmu_device *qcom_smmu_create(struct arm_smmu_device *smmu,
>> qsmmu->smmu.impl = impl;
>> qsmmu->cfg = data->cfg;
>>
>> + if (data->actlrcfg && (data->actlrcfg->size))
>> + qsmmu->actlrcfg = data->actlrcfg;
>> +
>> return &qsmmu->smmu;
>> }
>>
>> diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.h b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.h
>> index 593910567b88..4b6862715070 100644
>> --- a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.h
>> +++ b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.h
>> @@ -9,6 +9,7 @@
>> struct qcom_smmu {
>> struct arm_smmu_device smmu;
>> const struct qcom_smmu_config *cfg;
>> + const struct actlr_config *actlrcfg;
>> bool bypass_quirk;
>> u8 bypass_cbndx;
>> u32 stall_enabled;
>> @@ -25,6 +26,7 @@ struct qcom_smmu_config {
>> };
>>
>> struct qcom_smmu_match_data {
>> + const struct actlr_config *actlrcfg;
>> const struct qcom_smmu_config *cfg;
>> const struct arm_smmu_impl *impl;
>> const struct arm_smmu_impl *adreno_impl;
>> diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.c b/drivers/iommu/arm/arm-smmu/arm-smmu.c
>> index d6d1a2a55cc0..8e4faf015286 100644
>> --- a/drivers/iommu/arm/arm-smmu/arm-smmu.c
>> +++ b/drivers/iommu/arm/arm-smmu/arm-smmu.c
>> @@ -990,9 +990,10 @@ static int arm_smmu_find_sme(struct arm_smmu_device *smmu, u16 id, u16 mask)
>> * expect simply identical entries for this case, but there's
>> * no harm in accommodating the generalisation.
>> */
>> - if ((mask & smrs[i].mask) == mask &&
>> - !((id ^ smrs[i].id) & ~smrs[i].mask))
>> +
>> + if (smr_is_subset(smrs[i], id, mask))
>> return i;
>> +
>> /*
>> * If the new entry has any other overlap with an existing one,
>> * though, then there always exists at least one stream ID
>> diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.h b/drivers/iommu/arm/arm-smmu/arm-smmu.h
>> index 703fd5817ec1..b1638bbc41d4 100644
>> --- a/drivers/iommu/arm/arm-smmu/arm-smmu.h
>> +++ b/drivers/iommu/arm/arm-smmu/arm-smmu.h
>> @@ -501,6 +501,11 @@ static inline void arm_smmu_writeq(struct arm_smmu_device *smmu, int page,
>> writeq_relaxed(val, arm_smmu_page(smmu, page) + offset);
>> }
>>
>> +static inline bool smr_is_subset(struct arm_smmu_smr smrs, u16 id, u16 mask)
>> +{
>> + return (mask & smrs.mask) == mask && !((id ^ smrs.id) & ~smrs.mask);
>> +}
>> +
>> #define ARM_SMMU_GR0 0
>> #define ARM_SMMU_GR1 1
>> #define ARM_SMMU_CB(s, n) ((s)->numpage + (n))
>> --
>> 2.17.1
>>
>
>
> --
> With best wishes
> Dmitry


regards,
Bibek