The TCUs (Translation Control Units) and TBUs (Translation Buffer Units) are key components of the MMU-500. Multiple TBUs are connected to a single TCU over an interconnect. Each TBU contains a TLB that caches page tables. The MMU-500 implements a TBU for each connected master, and the TBU is designed, so that it is local to the master. A common TBU DT schema is added to describe the TBUs. The Qualcomm SDM845 and SC7280 platforms have an implementation of the SMMU-500, that has multiple TBUs. A vendor-specific DT schema is added to describe the resources for each TBU (register space, power-domains, interconnects and clocks). The TBU driver will manage the resources and allow the system to operate the TBUs during a context fault to obtain details by doing s1 inv, software + hardware page table walks etc. This is implemented with ATOS/eCATs as the ATS feature is not supported. Being able to query the TBUs is useful for debugging various hardware/software issues on these platforms. v5: - Drop the common TBU bindings and child nodes. These TBU functionalities are only Qualcomm specific and not generic. In the unmodified ARM MMU-500 implementation there are no TBU-specific resources, so just make them standalone DT nodes. (Robin) - The "qcom,stream-id-range" DT property now takes a phandle to the smmu and a stream ID range. v4: https://lore.kernel.org/all/20240201210529.7728-1-quic_c_gdjako@xxxxxxxxxxx/ - Create a common TBU schema. Move the vendor-specific properties into a separate schema that references the common one. (Rob) - Drop unused DT labels in example, fix regex. (Rob) - Properly rebase on latest code. v3: https://lore.kernel.org/r/20231220060236.18600-1-quic_c_gdjako@xxxxxxxxxxx - Having a TBU is not Qualcomm specific, so allow having TBU child nodes with no specific constraints on properties. For some of the vendor compatibles however, add a schema to describe specific properties and allow validation. (Rob) - Drop the useless reg-names DT property on TBUs. (Rob) - Make the stream-id-range DT property a common one. (Rob) - Fix the DT example. (Rob) - Minor fixes on the TBU driver. - Add support for SC7280 platforms. v2: https://lore.kernel.org/r/20231118042730.2799-1-quic_c_gdjako@xxxxxxxxxxx - Improve DT binding description, add full example. (Konrad) - Drop Qcom specific stuff from the generic binding. (Rob) - Unconditionally try to populate subnodes. (Konrad) - Improve TBU driver commit text, remove memory barriers. (Bjorn) - Move TBU stuff into separate file. Make the driver builtin. - TODO: Evaluate whether to keep TBU support as a separate driver or just instantiate things from qcom_smmu_impl_init() v1: https://lore.kernel.org/r/20231019021923.13939-1-quic_c_gdjako@xxxxxxxxxxx Georgi Djakov (7): dt-bindings: iommu: Add Qualcomm TBU bindings iommu/arm-smmu-qcom-tbu: Add Qualcomm TBU driver iommu/arm-smmu: Allow using a threaded handler for context interrupts iommu/arm-smmu-qcom: Use a custom context fault handler for sdm845 arm64: dts: qcom: sdm845: Add DT nodes for the TBUs iommu/arm-smmu-qcom: Use the custom fault handler on more platforms arm64: dts: qcom: sc7280: Add DT nodes for the TBUs .../devicetree/bindings/iommu/qcom,tbu.yaml | 65 +++ arch/arm64/boot/dts/qcom/sc7280.dtsi | 89 ++++ arch/arm64/boot/dts/qcom/sdm845.dtsi | 70 +++ drivers/iommu/Kconfig | 9 + drivers/iommu/arm/arm-smmu/Makefile | 1 + .../iommu/arm/arm-smmu/arm-smmu-qcom-tbu.c | 495 ++++++++++++++++++ drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c | 8 + drivers/iommu/arm/arm-smmu/arm-smmu-qcom.h | 2 + drivers/iommu/arm/arm-smmu/arm-smmu.c | 12 +- drivers/iommu/arm/arm-smmu/arm-smmu.h | 3 + 10 files changed, 752 insertions(+), 2 deletions(-) create mode 100644 Documentation/devicetree/bindings/iommu/qcom,tbu.yaml create mode 100644 drivers/iommu/arm/arm-smmu/arm-smmu-qcom-tbu.c
