diff mbox series

[v2,1/3] iommu/arm-smmu: introduction of ACTLR for custom prefetcher settings

Message ID 20231114135654.30475-2-quic_bibekkum@quicinc.com (mailing list archive)
State New, archived
Headers show
Series iommu/arm-smmu: introduction of ACTLR implementation for Qualcomm SoCs | expand

Commit Message

Bibek Kumar Patro Nov. 14, 2023, 1:56 p.m. UTC
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 <quic_bibekkum@quicinc.com>
---
 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(-)

--
2.17.1

Comments

Dmitry Baryshkov Nov. 14, 2023, 2:08 p.m. UTC | #1
On Tue, 14 Nov 2023 at 15:57, Bibek Kumar Patro
<quic_bibekkum@quicinc.com> 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 <quic_bibekkum@quicinc.com>
> ---
>  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.

> +};
> +
> +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
Robin Murphy Nov. 14, 2023, 4:55 p.m. UTC | #2
On 14/11/2023 1:56 pm, Bibek Kumar Patro 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 <quic_bibekkum@quicinc.com>
> ---
>   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;
> +};
> +
> +struct actlr_data {
> +	u16 sid;
> +	u16 mask;

Do we need to worry about masks? If you're already assuming that any SMR 
will be programmed to match a superset of the data here, surely a single 
unique ID per device would suffice?

> +	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))

How well have you tested this? ;)

> +			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;

Do we really need to replicate multiple parts of the data, or would it 
be sensible to just replace qsmmu->cfg with qsmmu->data and handle the 
further dereferences in the places that want them?

> +
>   	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)

Hmm, that name reads as implying the opposite of what it actually tests, 
not to mention that passing structs by value is a bit horrid as well :(

Thanks,
Robin.

> +{
> +	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
>
Bibek Kumar Patro Nov. 15, 2023, 5:42 a.m. UTC | #3
On 11/14/2023 7:38 PM, Dmitry Baryshkov wrote:
> On Tue, 14 Nov 2023 at 15:57, Bibek Kumar Patro
> <quic_bibekkum@quicinc.com> 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 <quic_bibekkum@quicinc.com>
>> ---
>>   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
Bibek Kumar Patro Nov. 15, 2023, 12:32 p.m. UTC | #4
On 11/14/2023 10:25 PM, Robin Murphy wrote:
> On 14/11/2023 1:56 pm, Bibek Kumar Patro 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 <quic_bibekkum@quicinc.com>
>> ---
>>   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;
>> +};
>> +
>> +struct actlr_data {
>> +    u16 sid;
>> +    u16 mask;
> 
> Do we need to worry about masks? If you're already assuming that any SMR 
> will be programmed to match a superset of the data here, surely a single 
> unique ID per device would suffice?
> 

If you refer to the arm_smmu_set_actlr below, mask would be needed as we 
would check for mask along with sid as well while assigning actlr 
configuration. Also with mask no of actlr entries can be reduces as
with out mask we have to have entry for each sid.

>> +    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))
> 
> How well have you tested this? ;)
> 

Well, this logic has worked pretty good for us till now in our
downstream implementation. :) (During testing as well this logic helped 
to better match the SMRs instead of manually mathcing the mask and SID 
which missed some SIDs)
Also this is already being used to arm_smmu_find_sme hence packaged this
logic in a wrapper to be used in other places as well(including ACTLR
register setting case here.)

>> +            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;
> 
> Do we really need to replicate multiple parts of the data, or would it 
> be sensible to just replace qsmmu->cfg with qsmmu->data and handle the 
> further dereferences in the places that want them?
> 
>> +
>>       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)
> 
> Hmm, that name reads as implying the opposite of what it actually tests, 
> not to mention that passing structs by value is a bit horrid as well :(
> 

It might be okay to name it as subset_of_smr() though. You have any 
other naming suggestion in mind which could correctly describe the
logic?

Thanks & regards,
Bibek

> Thanks,
> Robin.
> 
>> +{
>> +    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
>>
Bibek Kumar Patro Nov. 15, 2023, 1:54 p.m. UTC | #5
>> @@ -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;
> 
> Do we really need to replicate multiple parts of the data, or would it 
> be sensible to just replace qsmmu->cfg with qsmmu->data and handle the 
> further dereferences in the places that want them?
> 

Mm, could not understand this properly. :( Could you help explain more 
please?
As per my understanding aren't data and qsmmu different structures.
qcom_smmu is a superset of arm_smmu housing additonal properties
and qcom_smmu_match_data is kind of a superset of arm_smmu_impl with
additional specific implmentations, so both needs to be in place?
Apologies if I understood your statement incorrectly.

>> +
>>       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 {
>>   };
>>
Robin Murphy Nov. 15, 2023, 2:53 p.m. UTC | #6
On 2023-11-15 1:54 pm, Bibek Kumar Patro wrote:
> 
>>> @@ -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;
>>
>> Do we really need to replicate multiple parts of the data, or would it 
>> be sensible to just replace qsmmu->cfg with qsmmu->data and handle the 
>> further dereferences in the places that want them?
>>
> 
> Mm, could not understand this properly. :( Could you help explain more 
> please?
> As per my understanding aren't data and qsmmu different structures.
> qcom_smmu is a superset of arm_smmu housing additonal properties
> and qcom_smmu_match_data is kind of a superset of arm_smmu_impl with
> additional specific implmentations, so both needs to be in place?
> Apologies if I understood your statement incorrectly.

My point is that the data is static and constant, so there's really no 
point storing multiple pointers into different bits of it. So rather than:

	qsmmu->cfg = data->cfg;
	qssmu->actlrcfg = data->actlrcfg;
	...
	do_something(qsmmu->cfg);
	...
	do_other_thing(qsmmu->actlrcfg);

we can just store the one pointer and have:

	qsmmu->data = data;
	...
	do_something(qsmmu->data->cfg);
	...
	do_other_thing(qsmmu->data->actlrcfg);

Thanks,
Robin.

>>> +
>>>       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 {
>>>   };
>>>
Robin Murphy Nov. 15, 2023, 3:04 p.m. UTC | #7
On 2023-11-15 12:32 pm, Bibek Kumar Patro wrote:
> 
> 
> On 11/14/2023 10:25 PM, Robin Murphy wrote:
>> On 14/11/2023 1:56 pm, Bibek Kumar Patro 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 <quic_bibekkum@quicinc.com>
>>> ---
>>>   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;
>>> +};
>>> +
>>> +struct actlr_data {
>>> +    u16 sid;
>>> +    u16 mask;
>>
>> Do we need to worry about masks? If you're already assuming that any 
>> SMR will be programmed to match a superset of the data here, surely a 
>> single unique ID per device would suffice?
>>
> 
> If you refer to the arm_smmu_set_actlr below, mask would be needed as we 
> would check for mask along with sid as well while assigning actlr 
> configuration. Also with mask no of actlr entries can be reduces as
> with out mask we have to have entry for each sid.

But why? As far as I can tell, the design in patch #2 is to have a 
single data entry for each distinct device, since you're expecting to 
see a single SMR programmed to match at least the full id/mask range of 
the entry. However any SMR which matches that full range will by 
definition also match any smaller subset of that range as well, so we 
can uniquely identify any device in this context from just any *one* of 
its IDs, thus we could store less data and have simpler matching logic.

>>> +    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))
>>
>> How well have you tested this? ;)
>>
> 
> Well, this logic has worked pretty good for us till now in our
> downstream implementation. :) (During testing as well this logic helped 
> to better match the SMRs instead of manually mathcing the mask and SID 
> which missed some SIDs)
> Also this is already being used to arm_smmu_find_sme hence packaged this
> logic in a wrapper to be used in other places as well(including ACTLR
> register setting case here.)

1) Look at what you're matching the id and mask values *against*

2) Look at the polarity of the condition

3) Consider the old saying "two wrongs don't make a right"

>>> +            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;
>>
>> Do we really need to replicate multiple parts of the data, or would it 
>> be sensible to just replace qsmmu->cfg with qsmmu->data and handle the 
>> further dereferences in the places that want them?
>>
>>> +
>>>       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)
>>
>> Hmm, that name reads as implying the opposite of what it actually 
>> tests, not to mention that passing structs by value is a bit horrid as 
>> well :(
>>
> 
> It might be okay to name it as subset_of_smr() though. You have any 
> other naming suggestion in mind which could correctly describe the
> logic?

As above I think the ideal answer is to avoid the reason for factoring 
it out at all, by using a simpler matching process to begin with.

Thanks,
Robin.
Bibek Kumar Patro Nov. 17, 2023, 5:27 a.m. UTC | #8
On 11/15/2023 8:23 PM, Robin Murphy wrote:
> On 2023-11-15 1:54 pm, Bibek Kumar Patro wrote:
>>
>>>> @@ -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;
>>>
>>> Do we really need to replicate multiple parts of the data, or would 
>>> it be sensible to just replace qsmmu->cfg with qsmmu->data and handle 
>>> the further dereferences in the places that want them?
>>>
>>
>> Mm, could not understand this properly. :( Could you help explain more 
>> please?
>> As per my understanding aren't data and qsmmu different structures.
>> qcom_smmu is a superset of arm_smmu housing additonal properties
>> and qcom_smmu_match_data is kind of a superset of arm_smmu_impl with
>> additional specific implmentations, so both needs to be in place?
>> Apologies if I understood your statement incorrectly.
> 
> My point is that the data is static and constant, so there's really no 
> point storing multiple pointers into different bits of it. So rather than:
> 
>      qsmmu->cfg = data->cfg;
>      qssmu->actlrcfg = data->actlrcfg;
>      ...
>      do_something(qsmmu->cfg);
>      ...
>      do_other_thing(qsmmu->actlrcfg);
> 
> we can just store the one pointer and have:
> 
>      qsmmu->data = data;
>      ...
>      do_something(qsmmu->data->cfg);
>      ...
>      do_other_thing(qsmmu->data->actlrcfg);
> 
> Thanks,
> Robin.
> 

I see, this looks like probably we need a separate patch altogether for
this cleanup, as "cfg" is used in other fault handling places as well as 
i can see and is introduced as a part of different patch. Should we 
scope this work for a separate patch if it's okay?

Thanks,
Bibek
>>>> +
>>>>       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 {
>>>>   };
>>>>
Bibek Kumar Patro Nov. 20, 2023, 10:24 a.m. UTC | #9
On 11/15/2023 8:34 PM, Robin Murphy wrote:
> On 2023-11-15 12:32 pm, Bibek Kumar Patro wrote:
>>
>>
>> On 11/14/2023 10:25 PM, Robin Murphy wrote:
>>> On 14/11/2023 1:56 pm, Bibek Kumar Patro 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 <quic_bibekkum@quicinc.com>
>>>> ---
>>>>   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;
>>>> +};
>>>> +
>>>> +struct actlr_data {
>>>> +    u16 sid;
>>>> +    u16 mask;
>>>
>>> Do we need to worry about masks? If you're already assuming that any 
>>> SMR will be programmed to match a superset of the data here, surely a 
>>> single unique ID per device would suffice?
>>>

Thanks for this comment. I see now, only assuming smrs might not be able
to correctly set the ACTLR values for all the context banks without the
index. it should be smr = smmu->smrs[idx] instead of smr = smmu->smrs
or it will be considering the single SMR for all the associated devices.

>>
>> If you refer to the arm_smmu_set_actlr below, mask would be needed as 
>> we would check for mask along with sid as well while assigning actlr 
>> configuration. Also with mask no of actlr entries can be reduces as
>> with out mask we have to have entry for each sid.
> 
> But why? As far as I can tell, the design in patch #2 is to have a 
> single data entry for each distinct device, since you're expecting to 
> see a single SMR programmed to match at least the full id/mask range of 
> the entry. However any SMR which matches that full range will by 
> definition also match any smaller subset of that range as well, so we 
> can uniquely identify any device in this context from just any *one* of 
> its IDs, thus we could store less data and have simpler matching logic.
> 

I was going though your earlier reply once again and noticed we would
need to mention the context bank index against the smr as well to take
the right ACTLR value, as I replied to your earlier response above.

>>>> +    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;

It would be smr = smmu->smrs[idx] instead of smr = smmu->smrs to get
sid of individual device attached to corresponding context bank.

>>>> +    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))
>>>
>>> How well have you tested this? ;)
>>>
>>
>> Well, this logic has worked pretty good for us till now in our
>> downstream implementation. :) (During testing as well this logic 
>> helped to better match the SMRs instead of manually mathcing the mask 
>> and SID which missed some SIDs)
>> Also this is already being used to arm_smmu_find_sme hence packaged this
>> logic in a wrapper to be used in other places as well(including ACTLR
>> register setting case here.)
> 
> 1) Look at what you're matching the id and mask values *against*
> 

Got this now. Will take care of this in next version.

> 2) Look at the polarity of the condition
> 
> 3) Consider the old saying "two wrongs don't make a right"
> 

Noted.

>>>> +            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;
>>>
>>> Do we really need to replicate multiple parts of the data, or would 
>>> it be sensible to just replace qsmmu->cfg with qsmmu->data and handle 
>>> the further dereferences in the places that want them?
>>>
>>>> +
>>>>       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)
>>>
>>> Hmm, that name reads as implying the opposite of what it actually 
>>> tests, not to mention that passing structs by value is a bit horrid 
>>> as well :(
>>>
>>
>> It might be okay to name it as subset_of_smr() though. You have any 
>> other naming suggestion in mind which could correctly describe the
>> logic?
> 
> As above I think the ideal answer is to avoid the reason for factoring 
> it out at all, by using a simpler matching process to begin with.
>

As per the approach mentioned above to use the context bank index,
this same approach should be okay to go forward with.

Thanks Robin for you above comments, I have noted the inputs and will
take care of this in next version.

Thanks & regards,
Bibek

> Thanks,
> Robin.
diff mbox series

Patch

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;
+};
+
+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))