Existing exynos-iommu driver only supports SysMMU versions up to v5. But it's pretty much ready for basic usage with SysMMU v7, only small changes have to be done. As SysMMU version is tested dynamically (by reading the corresponding register), there is no need to introduce new compatible string.
One major change is that SysMMU v7 can have different register layouts: - with Virtual Machine support - without Virtual Machine support That can be checked by reading the capability registers. In case the SysMMU IP-core is VM-capable, the VM registers have to be used, and some additional initialization is needed. That is the case on E850-96 board, which non-secure SysMMU (v7.4) implements VM-capable register set. The patch series was tested on E850-96 board. Because at the moment there are no SysMMU users for that board, the testing was done using so called "Emulated Translation" registers available on SysMMU v7. That allows one to initiate the translation from CPU, by writing to those registers, and then reading the corresponding TLB registers to find out the translation result. The testing driver can be found in [1] tree. [1] https://github.com/joe-skb7/linux/tree/e850-96-mainline-iommu Sam Protsenko (4): iommu/exynos: Set correct dma mask for SysMMU v5+ iommu/exynos: Check if SysMMU v7 has VM registers iommu/exynos: Use lookup based approach to access v7 registers iommu/exynos: Add minimal support for SysMMU v7 with VM registers drivers/iommu/exynos-iommu.c | 112 ++++++++++++++++++++++++++++++++--- 1 file changed, 104 insertions(+), 8 deletions(-) -- 2.30.2 _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
