How to disable SMMU on Xavier?

[zhaorenliang1]

Hello Everyone:
I can only get a half rate of pcie through the Xavier platform comparing to the x86 platform.From the previous post,someone figured out that we should disable the SMMU.But I have no idea how to do that.Does anyone can help?Thanks Very Much!

[WayneWWW]

Do you want to remove the smmu for PCIe contoller 5?

pcie smmu issue

You can disable SMMU for PCIe controller-5 by removing the following two lines from the device-tree file iommus = <&smmu TEGRA_SID_PCIE5>; dma-coherent; Having said that, I genuinely feel that your code should be checked once as to why it can’t work with SMMU enabled for PCIe. It looks to me that you might not be using dma_alloc_* / dma_map_* APIs which isn’t a good thing to do from the system security point of view as the PCIe controller (based on accesses from endpoint) can access any random…