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| author | David S. Miller <davem@davemloft.net> | 2012-04-10 14:30:45 -0400 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2012-04-10 14:30:45 -0400 |
| commit | 06eb4eafbdc0796d741d139a44f1253278da8611 (patch) | |
| tree | fbdb44317130c371928154c9e6903e699fe2b995 /Documentation/DMA-attributes.txt | |
| parent | 32ed53b83ea5ec26a4dba90e18f5e0ff6c71eb48 (diff) | |
| parent | f68e556e23d1a4176b563bcb25d8baf2c5313f91 (diff) | |
Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
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. |