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| author | John W. Linville <linville@tuxdriver.com> | 2012-04-12 13:49:28 -0400 |
|---|---|---|
| committer | John W. Linville <linville@tuxdriver.com> | 2012-04-12 13:49:28 -0400 |
| commit | 8065248069097dddf9945acfb2081025e9618c16 (patch) | |
| tree | eddf3fb0372ba0f65c01382d386942ea8d18932d /Documentation/DMA-attributes.txt | |
| parent | e66a8ddff72e85605f2212a0ebc666c7e9116641 (diff) | |
| parent | b4838d12e1f3cb48c2489a0b08733b5dbf848297 (diff) | |
| download | blackbird-op-linux-8065248069097dddf9945acfb2081025e9618c16.tar.gz blackbird-op-linux-8065248069097dddf9945acfb2081025e9618c16.zip | |
Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/linville/wireless
Diffstat (limited to 'Documentation/DMA-attributes.txt')
| -rw-r--r-- | Documentation/DMA-attributes.txt | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/Documentation/DMA-attributes.txt b/Documentation/DMA-attributes.txt index b768cc0e402b..5c72eed89563 100644 --- a/Documentation/DMA-attributes.txt +++ b/Documentation/DMA-attributes.txt @@ -31,3 +31,21 @@ 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. + +DMA_ATTR_NON_CONSISTENT +----------------------- + +DMA_ATTR_NON_CONSISTENT lets the platform to choose to return either +consistent or non-consistent memory as it sees fit. By using this API, +you are guaranteeing to the platform that you have all the correct and +necessary sync points for this memory in the driver. |
