[PATCH V2] iommu/arm-smmu: add actlr settings for mdss on sa8775p platform

[PATCH V2] iommu/arm-smmu: add actlr settings for mdss on sa8775p platform

[Charan Teja Kalla]

Add ACTLR settings for the mdss device on Qualcomm SA8775P platform.
This is achieved by adding compatibility string for mdss in the actlr
client of match table.

Signed-off-by: Charan Teja Kalla <charan.kalla@oss.qualcomm.com>
---

Changed from V1:
  1) Added actlr setting only for MDSS and dropped for fastrpc. -- konrad
  2) ACTLR table is updated per alphanumeric order -- konrad 
  https://lore.kernel.org/all/20251105075307.1658329-1-charan.kalla@oss.qualcomm.com/

 drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
index 62874b18f645..0b400e22cb00 100644
--- a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
+++ b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
@@ -41,6 +41,8 @@ static const struct of_device_id qcom_smmu_actlr_client_of_match[] = {
 			.data = (const void *) (PREFETCH_DEEP | CPRE | CMTLB) },
 	{ .compatible = "qcom,fastrpc",
 			.data = (const void *) (PREFETCH_DEEP | CPRE | CMTLB) },
+	{ .compatible = "qcom,sa8775p-mdss",
+			.data = (const void *) (PREFETCH_DEFAULT | CMTLB) },
 	{ .compatible = "qcom,sc7280-mdss",
 			.data = (const void *) (PREFETCH_SHALLOW | CPRE | CMTLB) },
 	{ .compatible = "qcom,sc7280-venus",
-- 
2.34.1

Re: [PATCH V2] iommu/arm-smmu: add actlr settings for mdss on sa8775p platform

[Dmitry Baryshkov]

On Tue, Nov 18, 2025 at 10:48:22PM +0530, Charan Teja Kalla wrote:
> Add ACTLR settings for the mdss device on Qualcomm SA8775P platform.
> This is achieved by adding compatibility string for mdss in the actlr
> client of match table.
> 
> Signed-off-by: Charan Teja Kalla <charan.kalla@oss.qualcomm.com>
> ---
> 
> Changed from V1:
>   1) Added actlr setting only for MDSS and dropped for fastrpc. -- konrad
>   2) ACTLR table is updated per alphanumeric order -- konrad 
>   https://lore.kernel.org/all/20251105075307.1658329-1-charan.kalla@oss.qualcomm.com/
> 
>  drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
> index 62874b18f645..0b400e22cb00 100644
> --- a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
> +++ b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
> @@ -41,6 +41,8 @@ static const struct of_device_id qcom_smmu_actlr_client_of_match[] = {
>  			.data = (const void *) (PREFETCH_DEEP | CPRE | CMTLB) },
>  	{ .compatible = "qcom,fastrpc",
>  			.data = (const void *) (PREFETCH_DEEP | CPRE | CMTLB) },
> +	{ .compatible = "qcom,sa8775p-mdss",
> +			.data = (const void *) (PREFETCH_DEFAULT | CMTLB) },

What's the difference from SC7280? Why don't we need to set CPRE?

>  	{ .compatible = "qcom,sc7280-mdss",
>  			.data = (const void *) (PREFETCH_SHALLOW | CPRE | CMTLB) },
>  	{ .compatible = "qcom,sc7280-venus",
> -- 
> 2.34.1
> 

-- 
With best wishes
Dmitry

Re: [PATCH V2] iommu/arm-smmu: add actlr settings for mdss on sa8775p platform

[Charan Teja Kalla]

On 11/18/2025 11:33 PM, Dmitry Baryshkov wrote:
>> Add ACTLR settings for the mdss device on Qualcomm SA8775P platform.
>> This is achieved by adding compatibility string for mdss in the actlr
>> client of match table.
>>
>> Signed-off-by: Charan Teja Kalla <charan.kalla@oss.qualcomm.com>
>> ---
>>
>> Changed from V1:
>>   1) Added actlr setting only for MDSS and dropped for fastrpc. -- konrad
>>   2) ACTLR table is updated per alphanumeric order -- konrad 
>>   https://lore.kernel.org/all/20251105075307.1658329-1-
>> charan.kalla@oss.qualcomm.com/
>>
>>  drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c | 2 ++
>>  1 file changed, 2 insertions(+)
>>
>> diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
>> index 62874b18f645..0b400e22cb00 100644
>> --- a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
>> +++ b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
>> @@ -41,6 +41,8 @@ static const struct of_device_id qcom_smmu_actlr_client_of_match[] = {
>>  			.data = (const void *) (PREFETCH_DEEP | CPRE | CMTLB) },
>>  	{ .compatible = "qcom,fastrpc",
>>  			.data = (const void *) (PREFETCH_DEEP | CPRE | CMTLB) },
>> +	{ .compatible = "qcom,sa8775p-mdss",
>> +			.data = (const void *) (PREFETCH_DEFAULT | CMTLB) },
> What's the difference from SC7280? Why don't we need to set CPRE?

Sorry, I'm really not sure If your question imply to talk about the IP
level difference compared to SC7280 for mdss?

Regarding why don't we need CPRE -- these are QoS settings that does
control how well hw behaves i.e., related to performance settings not
the functional ones.  I guess, these settings are derived from factors
like how many masters are sharing a TBU, how crucial are masters using
that TBU(like important ones may be allowed to +7 or +15 and may be
others upto only +1 prefetch).

Thanks,
Charan

Re: [PATCH V2] iommu/arm-smmu: add actlr settings for mdss on sa8775p platform

[Konrad Dybcio]

On 11/19/25 7:06 PM, Charan Teja Kalla wrote:
> 
> 
> On 11/18/2025 11:33 PM, Dmitry Baryshkov wrote:
>>> Add ACTLR settings for the mdss device on Qualcomm SA8775P platform.
>>> This is achieved by adding compatibility string for mdss in the actlr
>>> client of match table.
>>>
>>> Signed-off-by: Charan Teja Kalla <charan.kalla@oss.qualcomm.com>
>>> ---
>>>
>>> Changed from V1:
>>>   1) Added actlr setting only for MDSS and dropped for fastrpc. -- konrad
>>>   2) ACTLR table is updated per alphanumeric order -- konrad 
>>>   https://lore.kernel.org/all/20251105075307.1658329-1-
>>> charan.kalla@oss.qualcomm.com/
>>>
>>>  drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c | 2 ++
>>>  1 file changed, 2 insertions(+)
>>>
>>> diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
>>> index 62874b18f645..0b400e22cb00 100644
>>> --- a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
>>> +++ b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
>>> @@ -41,6 +41,8 @@ static const struct of_device_id qcom_smmu_actlr_client_of_match[] = {
>>>  			.data = (const void *) (PREFETCH_DEEP | CPRE | CMTLB) },
>>>  	{ .compatible = "qcom,fastrpc",
>>>  			.data = (const void *) (PREFETCH_DEEP | CPRE | CMTLB) },
>>> +	{ .compatible = "qcom,sa8775p-mdss",
>>> +			.data = (const void *) (PREFETCH_DEFAULT | CMTLB) },
>> What's the difference from SC7280? Why don't we need to set CPRE?
> 
> Sorry, I'm really not sure If your question imply to talk about the IP
> level difference compared to SC7280 for mdss?

"SC7280 has MDSS, SA8775P also has (a slightly different) MDSS, is there
a reason these two have different settings"

> Regarding why don't we need CPRE -- these are QoS settings that does
> control how well hw behaves i.e., related to performance settings not
> the functional ones.  I guess, these settings are derived from factors
> like how many masters are sharing a TBU, how crucial are masters using
> that TBU(like important ones may be allowed to +7 or +15 and may be
> others upto only +1 prefetch).

And this is a good answer

Perhaps you could reword it a little and put in the commit message to
make it clear in case anyone has the same question in a year or so

Konrad

Re: [PATCH V2] iommu/arm-smmu: add actlr settings for mdss on sa8775p platform

[Dmitry Baryshkov]

On Thu, Nov 20, 2025 at 01:33:29PM +0100, Konrad Dybcio wrote:
> On 11/19/25 7:06 PM, Charan Teja Kalla wrote:
> > 
> > 
> > On 11/18/2025 11:33 PM, Dmitry Baryshkov wrote:
> >>> Add ACTLR settings for the mdss device on Qualcomm SA8775P platform.
> >>> This is achieved by adding compatibility string for mdss in the actlr
> >>> client of match table.
> >>>
> >>> Signed-off-by: Charan Teja Kalla <charan.kalla@oss.qualcomm.com>
> >>> ---
> >>>
> >>> Changed from V1:
> >>>   1) Added actlr setting only for MDSS and dropped for fastrpc. -- konrad
> >>>   2) ACTLR table is updated per alphanumeric order -- konrad 
> >>>   https://lore.kernel.org/all/20251105075307.1658329-1-
> >>> charan.kalla@oss.qualcomm.com/
> >>>
> >>>  drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c | 2 ++
> >>>  1 file changed, 2 insertions(+)
> >>>
> >>> diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
> >>> index 62874b18f645..0b400e22cb00 100644
> >>> --- a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
> >>> +++ b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
> >>> @@ -41,6 +41,8 @@ static const struct of_device_id qcom_smmu_actlr_client_of_match[] = {
> >>>  			.data = (const void *) (PREFETCH_DEEP | CPRE | CMTLB) },
> >>>  	{ .compatible = "qcom,fastrpc",
> >>>  			.data = (const void *) (PREFETCH_DEEP | CPRE | CMTLB) },
> >>> +	{ .compatible = "qcom,sa8775p-mdss",
> >>> +			.data = (const void *) (PREFETCH_DEFAULT | CMTLB) },
> >> What's the difference from SC7280? Why don't we need to set CPRE?
> > 
> > Sorry, I'm really not sure If your question imply to talk about the IP
> > level difference compared to SC7280 for mdss?
> 
> "SC7280 has MDSS, SA8775P also has (a slightly different) MDSS, is there
> a reason these two have different settings"
> 
> > Regarding why don't we need CPRE -- these are QoS settings that does
> > control how well hw behaves i.e., related to performance settings not
> > the functional ones.  I guess, these settings are derived from factors
> > like how many masters are sharing a TBU, how crucial are masters using
> > that TBU(like important ones may be allowed to +7 or +15 and may be
> > others upto only +1 prefetch).
> 
> And this is a good answer
> 
> Perhaps you could reword it a little and put in the commit message to
> make it clear in case anyone has the same question in a year or so

Yes, please. It would be really nice if you can add settings for other
MDSS devices too, not just the very few that management is caring
about.

-- 
With best wishes
Dmitry