On Fri, 25 May 2018, Christoph Hellwig wrote: > Only loongson-3 is DMA coherent and uses swiotlb. So move the dma > address translations stubs directly to the loongson-3 code, and remove > a few Kconfig indirections. SiByte should too though, at least for those boards, such as the SWARM and the BigSur, that can have DRAM over 4GiB (and 32-bit PCI devices plugged). I never got to have the wiring of swiotlb completed for these boards as I got distracted with getting set up to debug a DRAM controller issue observed in the form of memory data corruption with the banks fully populated (which might have to do something with the parameters of bank interleaving enabled in such a configuration, as replacing a single module with a smaller-sized one and therefore disabling interleaving, which can only work with all modules being the same size, makes the problem go away). FWIW, Maciej
