On Wed, Sep 23, 2020 at 08:48:26AM +0200, Marek Szyprowski wrote: > Hi Shaik, > > I've run into similar problem while adapting S5P-MFC and Exynos4-IS > drivers for generic IOMMU-DMA framework. Here is my first solution: > https://lore.kernel.org/linux-samsung-soc/20200918144833.14618-1-m.szyprowski@xxxxxxxxxxx/T/ > > > It allows to remap given buffer at the specific IOVA address, although > it doesn't guarantee that those specific addresses won't be later used > by the IOVA allocator. Probably it would make sense to add an API for > generic IOMMU-DMA framework to mark the given IOVA range as > reserved/unused to protect them. If you want to use IOVA addresses in a device otherwise managed by dma-iommu we need to expose an API through the dma API. Can you please include the iommu list in the discussion of your series? I don't think using the raw IOMMU API is a very idea in these drivers, we probably want a way to change the allocator algorithm or hint the next IOVA and keep using the normal DMA API. Maybe Robin has a better idea.
