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>

1 files changed, 1 insertions, 0 deletions

diff --git a/include/linux/dma-attrs.h b/include/linux/dma-attrs.h
index 547ab568d3ae..a37c10cc51c5 100644
--- a/include/linux/dma-attrs.h
+++ b/include/linux/dma-attrs.h
@@ -15,6 +15,7 @@ enum dma_attr {
         DMA_ATTR_WEAK_ORDERING,
         DMA_ATTR_WRITE_COMBINE,
         DMA_ATTR_NON_CONSISTENT,
+        DMA_ATTR_NO_KERNEL_MAPPING,
         DMA_ATTR_MAX,
 };