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Commit 8a413432 authored by Marek Szyprowski's avatar Marek Szyprowski
Browse files

common: DMA-mapping: add WRITE_COMBINE attribute 



DMA_ATTR_WRITE_COMBINE specifies that writes to the mapping may be
buffered to improve performance. It will be used by the replacement for
ARM/ARV32 specific dma_alloc_writecombine() function.

Signed-off-by: default avatarMarek Szyprowski <m.szyprowski@samsung.com>
Acked-by: default avatarKyungmin Park <kyungmin.park@samsung.com>
Reviewed-by: default avatarArnd Bergmann <arnd@arndb.de>
parent 9adc5374

Documentation/DMA-attributes.txt

+10 −0
Original line number Diff line number Diff line
@@ -31,3 +31,13 @@ may be weakly ordered, that is that reads and writes may pass each other. 
Since it is optional for platforms to implement DMA_ATTR_WEAK_ORDERING,

those that do not will simply ignore the attribute and exhibit default

behavior.



DMA_ATTR_WRITE_COMBINE

----------------------



DMA_ATTR_WRITE_COMBINE specifies that writes to the mapping may be

buffered to improve performance.



Since it is optional for platforms to implement DMA_ATTR_WRITE_COMBINE,

those that do not will simply ignore the attribute and exhibit default

behavior.

include/linux/dma-attrs.h

+1 −0
Original line number Diff line number Diff line
@@ -13,6 +13,7 @@ 
enum dma_attr {

	DMA_ATTR_WRITE_BARRIER,

	DMA_ATTR_WEAK_ORDERING,

	DMA_ATTR_WRITE_COMBINE,

	DMA_ATTR_MAX,

};