NVIDIA's Xavier (Tegra194) SOC has three ARM SMMU(MMU-500) instances. Two of the SMMU instances are used to interleave IOVA accesses across them. The IOVA accesses from HW devices are interleaved across these two SMMU instances and they need to be programmed identical.
The existing ARM SMMU driver can't be used in its current form for programming the two SMMU instances identically. But, most of the code can be shared between ARM SMMU driver and Tegra194 SMMU driver. Page fault handling and TLB sync operations need to know about specific instance of SMMU for correct fault handling and optimal TLB sync wait. Rest of the code doesn't need to know about number of SMMU instances. Based on this fact, The patch series here rearranges the arm-smmu.c code to allow sharing most of the ARM SMMU programming/iommu_ops code between ARM SMMU driver and Tegra194 SMMU driver and transparently handles programming of two SMMU instances. The third SMMU instance would use the existing ARM SMMU driver. Changes in v2: * Added CONFIG_ARM_SMMU_TEGRA to protect Tegra194 SMMU driver compilation * Enabled CONFIG_ARM_SMMU_TEGRA in defconfig * Added SMMU nodes in Tegra194 device tree Krishna Reddy (5): iommu/arm-smmu: rearrange arm-smmu.c code iommu/arm-smmu: Prepare fault, probe, sync functions for sharing code iommu/tegra194_smmu: Add Tegra194 SMMU driver arm64: defconfig: Enable ARM_SMMU_TEGRA arm64: tegra: Add SMMU nodes to Tegra194 device tree arch/arm64/boot/dts/nvidia/tegra194.dtsi | 148 ++ arch/arm64/configs/defconfig | 1 + drivers/iommu/Kconfig | 10 + drivers/iommu/Makefile | 1 + drivers/iommu/arm-smmu-common.c | 1971 +++++++++++++++++++++++++++ drivers/iommu/arm-smmu-common.h | 256 ++++ drivers/iommu/arm-smmu.c | 2167 +----------------------------- drivers/iommu/tegra194-smmu.c | 201 +++ 8 files changed, 2595 insertions(+), 2160 deletions(-) create mode 100644 drivers/iommu/arm-smmu-common.c create mode 100644 drivers/iommu/arm-smmu-common.h create mode 100644 drivers/iommu/tegra194-smmu.c -- 2.1.4
