[PATCH 1/6 v3] Docs: dt: add fsl-mc iommu-map device-tree binding

From: Nipun Gupta
Date: Fri Apr 27 2018 - 06:28:03 EST


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

Signed-off-by: Nipun Gupta <nipun.gupta@xxxxxxx>
---
.../devicetree/bindings/misc/fsl,qoriq-mc.txt | 39 ++++++++++++++++++++++
1 file changed, 39 insertions(+)

diff --git a/Documentation/devicetree/bindings/misc/fsl,qoriq-mc.txt b/Documentation/devicetree/bindings/misc/fsl,qoriq-mc.txt
index 6611a7c..8cbed4f 100644
--- a/Documentation/devicetree/bindings/misc/fsl,qoriq-mc.txt
+++ b/Documentation/devicetree/bindings/misc/fsl,qoriq-mc.txt
@@ -9,6 +9,25 @@ 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 insufficient to describe the relationship
+between ICIDs and IOMMUs, so an iommu-map property is used to define
+the set of possible ICIDs under a root DPRC and how they map to
+an IOMMU.
+
+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 +107,34 @@ Sub-nodes:
Value type: <phandle>
Definition: Specifies the phandle to the PHY device node associated
with the this dpmac.
+Optional properties:
+
+- iommu-map: Maps an ICID to an IOMMU and associated iommu-specifier
+ data.
+
+ The property is an arbitrary number of tuples of
+ (icid-base,iommu,iommu-base,length).
+
+ Any ICID i in the interval [icid-base, icid-base + length) is
+ associated with the listed IOMMU, with the iommu-specifier
+ (i - icid-base + iommu-base).

Example:

+ smmu: iommu@5000000 {
+ compatible = "arm,mmu-500";
+ #iommu-cells = <2>;
+ stream-match-mask = <0x7C00>;
+ ...
+ };
+
fsl_mc: fsl-mc@80c000000 {
compatible = "fsl,qoriq-mc";
reg = <0x00000008 0x0c000000 0 0x40>, /* MC portal base */
<0x00000000 0x08340000 0 0x40000>; /* MC control reg */
msi-parent = <&its>;
+ /* define map for ICIDs 23-64 */
+ iommu-map = <23 &smmu 23 41>;
#address-cells = <3>;
#size-cells = <1>;

--
1.9.1