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-rw-r--r--Documentation/devicetree/bindings/iommu/mediatek,iommu.txt13
1 files changed, 9 insertions, 4 deletions
diff --git a/Documentation/devicetree/bindings/iommu/mediatek,iommu.txt b/Documentation/devicetree/bindings/iommu/mediatek,iommu.txt
index cd1b1cd7b5c4..53c20cae309f 100644
--- a/Documentation/devicetree/bindings/iommu/mediatek,iommu.txt
+++ b/Documentation/devicetree/bindings/iommu/mediatek,iommu.txt
@@ -1,7 +1,9 @@
* Mediatek IOMMU Architecture Implementation
- Some Mediatek SOCs contain a Multimedia Memory Management Unit (M4U) which
-uses the ARM Short-Descriptor translation table format for address translation.
+ Some Mediatek SOCs contain a Multimedia Memory Management Unit (M4U), and
+this M4U have two generations of HW architecture. Generation one uses flat
+pagetable, and only supports 4K size page mapping. Generation two uses the
+ARM Short-Descriptor translation table format for address translation.
About the M4U Hardware Block Diagram, please check below:
@@ -36,7 +38,9 @@ in each larb. Take a example, There are many ports like MC, PP, VLD in the
video decode local arbiter, all these ports are according to the video HW.
Required properties:
-- compatible : must be "mediatek,mt8173-m4u".
+- compatible : must be one of the following string:
+ "mediatek,mt2701-m4u" for mt2701 which uses generation one m4u HW.
+ "mediatek,mt8173-m4u" for mt8173 which uses generation two m4u HW.
- reg : m4u register base and size.
- interrupts : the interrupt of m4u.
- clocks : must contain one entry for each clock-names.
@@ -46,7 +50,8 @@ Required properties:
according to the local arbiter index, like larb0, larb1, larb2...
- iommu-cells : must be 1. This is the mtk_m4u_id according to the HW.
Specifies the mtk_m4u_id as defined in
- dt-binding/memory/mt8173-larb-port.h.
+ dt-binding/memory/mt2701-larb-port.h for mt2701 and
+ dt-binding/memory/mt8173-larb-port.h for mt8173
Example:
iommu: iommu@10205000 {