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 > Suggested-by: Akhil P Oommen <akhilpo@xxxxxxxxxxxxxx> > Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan@xxxxxxxxxxxxxx> > --- > drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c | 12 +++++++++--- > 1 file changed, 9 insertions(+), 3 deletions(-) > > diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c > index bea3ee0dabc2..03f048aebb80 100644 > --- a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c > +++ b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c > @@ -345,11 +345,17 @@ struct arm_smmu_device *qcom_smmu_impl_init(struct arm_smmu_device *smmu) > { > const struct device_node *np = smmu->dev->of_node; > > - if (of_match_node(qcom_smmu_impl_of_match, np)) > - return qcom_smmu_create(smmu, &qcom_smmu_impl); > - > + /* > + * Do not change this order of implementation, i.e., first adreno > + * smmu impl and then apss smmu since we can have both implementing > + * arm,mmu-500 in which case we will miss setting adreno smmu specific > + * features if the order is changed. > + */ > if (of_device_is_compatible(np, "qcom,adreno-smmu")) > return qcom_smmu_create(smmu, &qcom_adreno_smmu_impl); > > + if (of_match_node(qcom_smmu_impl_of_match, np)) > + return qcom_smmu_create(smmu, &qcom_smmu_impl); > + > return smmu; > } > -- > QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member > of Code Aurora Forum, hosted by The Linux Foundation >