[PATCH 4/7] v4l: videobuf2: add IOMMU based DMA memory allocator

Arnd Bergmann arnd at arndb.de
Mon Apr 18 10:15:48 EDT 2011

On Monday 18 April 2011, Marek Szyprowski wrote:
> From: Andrzej Pietrasiewicz <andrzej.p at samsung.com>
> This patch adds new videobuf2 memory allocator dedicated to devices that
> supports IOMMU DMA mappings. A device with IOMMU module and a driver
> with include/iommu.h compatible interface is required. This allocator
> aquires memory with standard alloc_page() call and doesn't suffer from
> memory fragmentation issues. The allocator support following page sizes:
> 4KiB, 64KiB, 1MiB and 16MiB to reduce iommu translation overhead.

My feeling is that this is not the right abstraction. Why can't you
just implement the regular dma-mapping.h interfaces for your IOMMU
so that the videobuf code can use the existing allocators?


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