On Fri 26 Feb 03:55 CST 2021, Sai Prakash Ranjan wrote:
Adreno(GPU) SMMU and APSS(Application Processor SubSystem) SMMU
both implement "arm,mmu-500" in some QTI SoCs and to run through
adreno smmu specific implementation such as enabling split pagetables
support, we need to match the "qcom,adreno-smmu" compatible first
before apss smmu or else we will be running apps smmu implementation
for adreno smmu and the additional features for adreno smmu is never
set. For ex: we have "qcom,sc7280-smmu-500" compatible for both apps
and adreno smmu implementing "arm,mmu-500", so the adreno smmu
implementation is never reached because the current sequence checks
for apps smmu compatible(qcom,sc7280-smmu-500) first and runs that
specific impl and we never reach adreno smmu specific implementation.
So you're saying that you have a single SMMU instance that's compatible
with both an entry in qcom_smmu_impl_of_match[] and "qcom,adreno-smmu"?
Per your proposed change we will pick the adreno ops _only_ for this
component, essentially disabling the non-Adreno quirks selected by the
qcom impl. As such keeping the non-adreno compatible in the
qcom_smmu_impl_init[] seems to only serve to obfuscate the situation.
Don't we somehow need the combined set of quirks? (At least if we're
running this with a standard UEFI based boot flow?)
Regards,
Bjorn
From: Rob Clark <hidden> Date: 2021-02-26 18:24:41
On Fri, Feb 26, 2021 at 9:24 AM Bjorn Andersson
[off-list ref] wrote:
On Fri 26 Feb 03:55 CST 2021, Sai Prakash Ranjan wrote:
quoted
Adreno(GPU) SMMU and APSS(Application Processor SubSystem) SMMU
both implement "arm,mmu-500" in some QTI SoCs and to run through
adreno smmu specific implementation such as enabling split pagetables
support, we need to match the "qcom,adreno-smmu" compatible first
before apss smmu or else we will be running apps smmu implementation
for adreno smmu and the additional features for adreno smmu is never
set. For ex: we have "qcom,sc7280-smmu-500" compatible for both apps
and adreno smmu implementing "arm,mmu-500", so the adreno smmu
implementation is never reached because the current sequence checks
for apps smmu compatible(qcom,sc7280-smmu-500) first and runs that
specific impl and we never reach adreno smmu specific implementation.
So you're saying that you have a single SMMU instance that's compatible
with both an entry in qcom_smmu_impl_of_match[] and "qcom,adreno-smmu"?
Per your proposed change we will pick the adreno ops _only_ for this
component, essentially disabling the non-Adreno quirks selected by the
qcom impl. As such keeping the non-adreno compatible in the
qcom_smmu_impl_init[] seems to only serve to obfuscate the situation.
Don't we somehow need the combined set of quirks? (At least if we're
running this with a standard UEFI based boot flow?)
are you thinking of the apps-smmu handover of display context bank?
That shouldn't change, the only thing that changes is that gpu-smmu
becomes an mmu-500, whereas previously only apps-smmu was..
BR,
-R
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From: Jordan Crouse <hidden> Date: 2021-02-26 18:49:08
On Fri, Feb 26, 2021 at 11:24:52AM -0600, Bjorn Andersson wrote:
On Fri 26 Feb 03:55 CST 2021, Sai Prakash Ranjan wrote:
quoted
Adreno(GPU) SMMU and APSS(Application Processor SubSystem) SMMU
both implement "arm,mmu-500" in some QTI SoCs and to run through
adreno smmu specific implementation such as enabling split pagetables
support, we need to match the "qcom,adreno-smmu" compatible first
before apss smmu or else we will be running apps smmu implementation
for adreno smmu and the additional features for adreno smmu is never
set. For ex: we have "qcom,sc7280-smmu-500" compatible for both apps
and adreno smmu implementing "arm,mmu-500", so the adreno smmu
implementation is never reached because the current sequence checks
for apps smmu compatible(qcom,sc7280-smmu-500) first and runs that
specific impl and we never reach adreno smmu specific implementation.
So you're saying that you have a single SMMU instance that's compatible
with both an entry in qcom_smmu_impl_of_match[] and "qcom,adreno-smmu"?
Per your proposed change we will pick the adreno ops _only_ for this
component, essentially disabling the non-Adreno quirks selected by the
qcom impl. As such keeping the non-adreno compatible in the
qcom_smmu_impl_init[] seems to only serve to obfuscate the situation.
Don't we somehow need the combined set of quirks? (At least if we're
running this with a standard UEFI based boot flow?)
We *do* need the combined set of quirks, so there has to be an adreno-smmu
impelmentation that matches the "generic" implementation with a few extra
function hooks added on. I'm not sure if there is a clever way to figure out how
to meld the implementation hooks at runtime but the alternative is to just make
sure that the adreno-smmu static struct calls the same quirks as its generic
partner.
Jordan
On Fri, Feb 26, 2021 at 9:24 AM Bjorn Andersson
[off-list ref] wrote:
quoted
On Fri 26 Feb 03:55 CST 2021, Sai Prakash Ranjan wrote:
quoted
Adreno(GPU) SMMU and APSS(Application Processor SubSystem) SMMU
both implement "arm,mmu-500" in some QTI SoCs and to run through
adreno smmu specific implementation such as enabling split pagetables
support, we need to match the "qcom,adreno-smmu" compatible first
before apss smmu or else we will be running apps smmu implementation
for adreno smmu and the additional features for adreno smmu is never
set. For ex: we have "qcom,sc7280-smmu-500" compatible for both apps
and adreno smmu implementing "arm,mmu-500", so the adreno smmu
implementation is never reached because the current sequence checks
for apps smmu compatible(qcom,sc7280-smmu-500) first and runs that
specific impl and we never reach adreno smmu specific implementation.
So you're saying that you have a single SMMU instance that's compatible
with both an entry in qcom_smmu_impl_of_match[] and "qcom,adreno-smmu"?
Per your proposed change we will pick the adreno ops _only_ for this
component, essentially disabling the non-Adreno quirks selected by the
qcom impl. As such keeping the non-adreno compatible in the
qcom_smmu_impl_init[] seems to only serve to obfuscate the situation.
Don't we somehow need the combined set of quirks? (At least if we're
running this with a standard UEFI based boot flow?)
are you thinking of the apps-smmu handover of display context bank?
That shouldn't change, the only thing that changes is that gpu-smmu
becomes an mmu-500, whereas previously only apps-smmu was..
The current logic picks one of:
1) is the compatible mentioned in qcom_smmu_impl_of_match[]
2) is the compatible an adreno
3) no quirks needed
The change flips the order of these, so the only way I can see this
change affecting things is if we expected a match on #2, but we got one
on #1.
Which implies that the instance that we want to act according to the
adreno impl was listed in qcom_smmu_impl_of_match[] - which either is
wrong, or there's a single instance that needs both behaviors.
(And I believe Jordan's answer confirms the latter - there's a single
SMMU instance that needs all them quirks at once)
Regards,
Bjorn
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From: Jordan Crouse <hidden> Date: 2021-02-26 19:55:18
On Fri, Feb 26, 2021 at 11:48:13AM -0700, Jordan Crouse wrote:
On Fri, Feb 26, 2021 at 11:24:52AM -0600, Bjorn Andersson wrote:
quoted
On Fri 26 Feb 03:55 CST 2021, Sai Prakash Ranjan wrote:
quoted
Adreno(GPU) SMMU and APSS(Application Processor SubSystem) SMMU
both implement "arm,mmu-500" in some QTI SoCs and to run through
adreno smmu specific implementation such as enabling split pagetables
support, we need to match the "qcom,adreno-smmu" compatible first
before apss smmu or else we will be running apps smmu implementation
for adreno smmu and the additional features for adreno smmu is never
set. For ex: we have "qcom,sc7280-smmu-500" compatible for both apps
and adreno smmu implementing "arm,mmu-500", so the adreno smmu
implementation is never reached because the current sequence checks
for apps smmu compatible(qcom,sc7280-smmu-500) first and runs that
specific impl and we never reach adreno smmu specific implementation.
So you're saying that you have a single SMMU instance that's compatible
with both an entry in qcom_smmu_impl_of_match[] and "qcom,adreno-smmu"?
Per your proposed change we will pick the adreno ops _only_ for this
component, essentially disabling the non-Adreno quirks selected by the
qcom impl. As such keeping the non-adreno compatible in the
qcom_smmu_impl_init[] seems to only serve to obfuscate the situation.
Don't we somehow need the combined set of quirks? (At least if we're
running this with a standard UEFI based boot flow?)
We *do* need the combined set of quirks, so there has to be an adreno-smmu
impelmentation that matches the "generic" implementation with a few extra
function hooks added on. I'm not sure if there is a clever way to figure out how
to meld the implementation hooks at runtime but the alternative is to just make
sure that the adreno-smmu static struct calls the same quirks as its generic
partner.
To clarify, the gpu-smmu doesn't strictly need the s2cr handoff or the cfg_probe
though it wouldn't hurt to have them since they would be essentially
passthroughs for the GPU. We do need to capture errata like the
sdm845_smmu500_reset which is already part of the upstream adreno
implementation.
I think the main takeaway is that if a new errata or quirk is added
for main mmu500 it needs to be considered for adreno-smmu too.
Jordan