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authorMagnus Damm <damm@igel.co.jp>2009-06-17 00:32:36 +0200
committerLinus Torvalds <torvalds@linux-foundation.org>2009-06-17 04:47:40 +0200
commit720b17e759a50635c429ccaa2ec3d01edb4f92d6 (patch)
tree8f6d86a05b328a54bd312b62e1fbc844c1dc30ba /mm
parentmm: introduce follow_pfn() (diff)
downloadlinux-720b17e759a50635c429ccaa2ec3d01edb4f92d6.tar.xz
linux-720b17e759a50635c429ccaa2ec3d01edb4f92d6.zip
videobuf-dma-contig: zero copy USERPTR support
Since videobuf-dma-contig is designed to handle physically contiguous memory, this patch modifies the videobuf-dma-contig code to only accept a user space pointer to physically contiguous memory. For now only VM_PFNMAP vmas are supported, so forget hotplug. On SuperH Mobile we use this with our sh_mobile_ceu_camera driver together with various multimedia accelerator blocks that are exported to user space using UIO. The UIO kernel code exports physically contiguous memory to user space and lets the user space application mmap() this memory and pass a pointer using the USERPTR interface for V4L2 zero copy operation. With this approach we support zero copy capture, hardware scaling and various forms of hardware encoding and decoding. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Magnus Damm <damm@igel.co.jp> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Paul Mundt <lethal@linux-sh.org> Acked-by: Mauro Carvalho Chehab <mchehab@infradead.org> Cc: Hans Verkuil <hverkuil@xs4all.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
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