* [PATCH] Add 'dma-coherent' property as a standard property
@ 2020-03-05 0:36 Rob Herring
0 siblings, 0 replies; only message in thread
From: Rob Herring @ 2020-03-05 0:36 UTC (permalink / raw)
To: devicetree-spec-u79uwXL29TY76Z2rM5mHXA
The 'dma-coherent' property was added for architectures which by default
have non-coherent I/O (e.g. Arm) as a way to specify certain devices are
coherent. It's been in use since 2012.
Signed-off-by: Rob Herring <robh-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
---
source/devicetree-basics.rst | 13 +++++++++++++
1 file changed, 13 insertions(+)
diff --git a/source/devicetree-basics.rst b/source/devicetree-basics.rst
index 8292a312ba5a..90d49a1835c7 100644
--- a/source/devicetree-basics.rst
+++ b/source/devicetree-basics.rst
@@ -804,6 +804,19 @@ Description:
from the *#size-cells* of this node (the node in which the dma-ranges
property appears).
+dma-coherent
+~~~~~~~~~~~~
+
+Property name: ``dma-coherent``
+
+Value type: ``<empty>``
+
+Description:
+ For architectures which are by default non-coherent for I/O, the
+ *dma-coherent* property is used to indicate a device is capable of
+ coherent DMA operations. Some architectures have coherent DMA by default
+ and this property is not applicable.
+
name (deprecated)
~~~~~~~~~~~~~~~~~
--
2.20.1
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