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authorMarek Szyprowski <m.szyprowski@samsung.com>2012-10-15 14:03:51 (GMT)
committerInki Dae <daeinki@gmail.com>2012-11-29 11:30:34 (GMT)
commit4b9347dcbe3b426d19bda99b2061a2d1fe5a2dce (patch)
tree0a83c280f8a7bffa01ab8c86a443001b7a80e048 /Documentation/DMA-attributes.txt
parente7783ba3bf1c631278be6620875fbfa6b0eba905 (diff)
common: DMA-mapping: add DMA_ATTR_FORCE_CONTIGUOUS attribute
This patch adds DMA_ATTR_FORCE_CONTIGUOUS attribute to the DMA-mapping subsystem. By default DMA-mapping subsystem is allowed to assemble the buffer allocated by dma_alloc_attrs() function from individual pages if it can be mapped as contiguous chunk into device dma address space. By specifing this attribute the allocated buffer is forced to be contiguous also in physical memory. Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Diffstat (limited to 'Documentation/DMA-attributes.txt')
-rw-r--r--Documentation/DMA-attributes.txt9
1 files changed, 9 insertions, 0 deletions
diff --git a/Documentation/DMA-attributes.txt b/Documentation/DMA-attributes.txt
index f503090..e59480d 100644
--- a/Documentation/DMA-attributes.txt
+++ b/Documentation/DMA-attributes.txt
@@ -91,3 +91,12 @@ transferred to 'device' domain. This attribute can be also used for
dma_unmap_{single,page,sg} functions family to force buffer to stay in
device domain after releasing a mapping for it. Use this attribute with
care!
+
+DMA_ATTR_FORCE_CONTIGUOUS
+-------------------------
+
+By default DMA-mapping subsystem is allowed to assemble the buffer
+allocated by dma_alloc_attrs() function from individual pages if it can
+be mapped as contiguous chunk into device dma address space. By
+specifing this attribute the allocated buffer is forced to be contiguous
+also in physical memory.

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