Nishanth Peethambaran <nishanth.p@xxxxxxxxx> wrote @ Thu, 20 Jun 2013 10:55:32 +0200: > Thinking again on it, I feel the translation of dma-attr should happen > when dma-mapping code makes calls to " iommu mapping" API. > "iommu mapping" API which does iova management and make iommu API > calls could be taken out from dma-mapping.c, for which I see > discussion already happening for arm64. According to the discussion ARM64:dma-mapping, I got an implression that IOVA management part in ARM:dma-mapping API would be a new common module(ie: /lib/iommu-helper.c), but still IOMMU API itself would reamin as primitive as what they are. +--------------------------------- | DMA mapping API | +----------------- +--------------+-----------+ | DMA mapping API($ARCH) | IOMMU API | IOVA MGT | +------------------ +--------------+-----------+ |IOMMU API(H/W)| +--------------+ | IOMMU H/W | +--------------+ > If devices allocate via dma-mapping API, physical mem allocation, iova > allocation and iommu mapping happens internally. > Devices may allocate physical memory using any allocator (say ION > including carveout area), use "iommu mapping" API which will do iova > allocation and iommu mapping. The prot flags could be useful in this > case as well - not sure whether we would need dma-attrs here. I haven't followed ION recently, but can't ION backed by DMA mapping API instead of using IOMMU API directly? -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
