From 1f17804d368a3735700a32850cfb35b56794c186 Mon Sep 17 00:00:00 2001 From: Marek Szyprowski Date: Fri, 23 Dec 2011 09:30:47 +0100 Subject: [PATCH] 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: Marek Szyprowski Acked-by: Kyungmin Park Reviewed-by: Arnd Bergmann --- Documentation/DMA-attributes.txt | 10 ++++++++++ include/linux/dma-attrs.h | 1 + 2 files changed, 11 insertions(+) diff --git a/Documentation/DMA-attributes.txt b/Documentation/DMA-attributes.txt index b768cc0e402b..811a5d458dae 100644 --- a/Documentation/DMA-attributes.txt +++ b/Documentation/DMA-attributes.txt @@ -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. diff --git a/include/linux/dma-attrs.h b/include/linux/dma-attrs.h index 71ad34eca6e3..ada61e1abf29 100644 --- a/include/linux/dma-attrs.h +++ b/include/linux/dma-attrs.h @@ -13,6 +13,7 @@ enum dma_attr { DMA_ATTR_WRITE_BARRIER, DMA_ATTR_WEAK_ORDERING, + DMA_ATTR_WRITE_COMBINE, DMA_ATTR_MAX, }; -- 2.39.2