Re: [PATCH 1/6] Docs: dt: add fsl-mc iommu-parent device-tree binding

The existing IOMMU bindings cannot be used to specify the relationship
between fsl-mc devices and IOMMUs. This patch adds a binding for
mapping fsl-mc devices to IOMMUs, using a new iommu-parent property.

Signed-off-by: Nipun Gupta <redacted>
---
 .../devicetree/bindings/misc/fsl,qoriq-mc.txt      | 31 ++++++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/Documentation/devicetree/bindings/misc/fsl,qoriq-mc.txt b/Documentation/devicetree/bindings/misc/fsl,qoriq-mc.txt
index 6611a7c..011c7d6 100644
--- a/Documentation/devicetree/bindings/misc/fsl,qoriq-mc.txt
+++ b/Documentation/devicetree/bindings/misc/fsl,qoriq-mc.txt

@@ -9,6 +9,24 @@ blocks that can be used to create functional hardware objects/devices
 such as network interfaces, crypto accelerator instances, L2 switches,
 etc.
 
+For an overview of the DPAA2 architecture and fsl-mc bus see:
+drivers/staging/fsl-mc/README.txt
+
+As described in the above overview, all DPAA2 objects in a DPRC share the
+same hardware "isolation context" and a 10-bit value called an ICID
+(isolation context id) is expressed by the hardware to identify
+the requester.
+
+The generic 'iommus' property is cannot be used to describe the relationship
+between fsl-mc and IOMMUs, so an iommu-parent property is used to define
+the same.

+
+For generic IOMMU bindings, see
+Documentation/devicetree/bindings/iommu/iommu.txt.
+
+For arm-smmu binding, see:
+Documentation/devicetree/bindings/iommu/arm,smmu.txt.
+
 Required properties:
 
     - compatible

@@ -88,14 +106,27 @@ Sub-nodes:
               Value type: <phandle>
               Definition: Specifies the phandle to the PHY device node associated
                           with the this dpmac.
+Optional properties:
+
+- iommu-parent: Maps the devices on fsl-mc bus to an IOMMU.
+  The property specifies the IOMMU behind which the devices on
+  fsl-mc bus are residing.