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| author | Linux Build Service Account <lnxbuild@localhost> | 2017-03-10 02:07:10 -0800 |
|---|---|---|
| committer | Gerrit - the friendly Code Review server <code-review@localhost> | 2017-03-10 02:07:10 -0800 |
| commit | c03b5c2d1c8cb3a6f740d372756ec2e8369b2b90 (patch) | |
| tree | b95c8f19678e97b5ef98f27c10d82a11cc470cd4 /Documentation | |
| parent | 7577433126b5efaa164536f8ccb34b408a914f83 (diff) | |
| parent | 37a29f1605993040e3f21fa2fb51e14d9de11e65 (diff) | |
Merge "arm64: dma-mapping: optimize unmap coherency check"
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/DMA-attributes.txt | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/Documentation/DMA-attributes.txt b/Documentation/DMA-attributes.txt index 6eadd564a247..2ad68dbbaaae 100644 --- a/Documentation/DMA-attributes.txt +++ b/Documentation/DMA-attributes.txt @@ -132,6 +132,11 @@ DMA_ATTR_FORCE_COHERENT When passed to a DMA map call the DMA_ATTR_FORCE_COHERENT DMA attribute can be used to force a buffer to be mapped as IO coherent. + +When the DMA_ATTR_FORCE_COHERENT attribute is set during a map call ensure +that it is also set during for the matching unmap call to ensure that the +correct cache maintenance is carried out. + This DMA attribute is only currently supported for arm64 stage 1 IOMMU mappings. @@ -143,5 +148,9 @@ coherent. The DMA_ATTR_FORCE_NON_COHERENT DMA attribute overrides the buffer IO coherency configuration set by making the device IO coherent. +When the DMA_ATTR_FORCE_NON_COHERENT attribute is set during a map call +ensure that it is also set during for the matching unmap call to ensure +that the correct cache maintenance is carried out. + This DMA attribute is only currently supported for arm64 stage 1 IOMMU mappings. |