X-Git-Url: https://git.karo-electronics.de/?a=blobdiff_plain;f=Documentation%2FDMA-attributes.txt;h=b768cc0e402b8e6f1cfa8ae0b0f23c4e1c50168a;hb=52bd080d5c87af556bf71e3b07bdd8586166c43b;hp=6d772f84b477c9f5a4698e87d50fb63649af83d3;hpb=a815752ac0ffdb910e92958d41d28f4fb28e5296;p=mv-sheeva.git

diff --git a/Documentation/DMA-attributes.txt b/Documentation/DMA-attributes.txt
index 6d772f84b47..b768cc0e402 100644
--- a/Documentation/DMA-attributes.txt
+++ b/Documentation/DMA-attributes.txt
@@ -22,3 +22,12 @@ ready and available in memory.  The DMA of the "completion indication"
 could race with data DMA.  Mapping the memory used for completion
 indications with DMA_ATTR_WRITE_BARRIER would prevent the race.
 
+DMA_ATTR_WEAK_ORDERING
+----------------------
+
+DMA_ATTR_WEAK_ORDERING specifies that reads and writes to the mapping
+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.