On Fri 26 Feb 12:23 CST 2021, Rob Clark wrote: > On Fri, Feb 26, 2021 at 9:24 AM Bjorn Andersson > <bjorn.andersson@xxxxxxxxxx> wrote: > > > > 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?) > > > > 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
