common: DMA-mapping: add DMA_ATTR_NO_KERNEL_MAPPING attribute
authorMarek Szyprowski <m.szyprowski@samsung.com>
Wed, 16 May 2012 13:20:37 +0000 (15:20 +0200)
committerMarek Szyprowski <m.szyprowski@samsung.com>
Mon, 30 Jul 2012 10:25:46 +0000 (12:25 +0200)
commitd5724f172fd1406c6962c4d2e27228b8e9e83642
tree2a4f868db55fcda60608486771e8f8407f197e75
parent64ccc9c033c6089b2d426dad3c56477ab066c999
common: DMA-mapping: add DMA_ATTR_NO_KERNEL_MAPPING attribute

This patch adds DMA_ATTR_NO_KERNEL_MAPPING attribute which lets the
platform to avoid creating a kernel virtual mapping for the allocated
buffer. On some architectures creating such mapping is non-trivial task
and consumes very limited resources (like kernel virtual address space
or dma consistent address space). Buffers allocated with this attribute
can be only passed to user space by calling dma_mmap_attrs().

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Kyungmin Park <kyungmin.park@samsung.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Documentation/DMA-attributes.txt
include/linux/dma-attrs.h