Patchwork [13/14] common: DMA-mapping: add WRITE_COMBINE attribute

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Submitter Marek Szyprowski
Date Dec. 23, 2011, 12:27 p.m.
Message ID <1324643253-3024-14-git-send-email-m.szyprowski@samsung.com>
Download mbox | patch
Permalink /patch/133039/
State Not Applicable
Delegated to: David Miller
Headers show

Comments

Marek Szyprowski - Dec. 23, 2011, 12:27 p.m.
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 <m.szyprowski@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
---
 Documentation/DMA-attributes.txt |   10 ++++++++++
 include/linux/dma-attrs.h        |    1 +
 2 files changed, 11 insertions(+), 0 deletions(-)

Patch

diff --git a/Documentation/DMA-attributes.txt b/Documentation/DMA-attributes.txt
index b768cc0..811a5d4 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 71ad34e..ada61e1 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,
 };