[PATCH 1/6] Docs: dt: add fsl-mc iommu-parent device-tree binding
From: robin.murphy@arm.com (Robin Murphy)
Date: 2018-03-05 14:53:21
Also in:
linux-devicetree, linux-iommu, linuxppc-dev, lkml
On 05/03/18 14:29, Nipun Gupta wrote:
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.
Given that allowing "msi-parent" for #msi-cells > 1 is merely a backward-compatibility bodge full of hard-coded assumptions, why would we want to knowingly introduce a similarly unpleasant equivalent for IOMMUs? What's wrong with "iommu-map"?
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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.
IOW, precisely the case for which "{msi,iommu}-map" exist. Yes, I know
they're currently documented under bindings/pci, but they're not really
intended to be absolutely PCI-specific.
Robin.
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+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. Example: + smmu: iommu at 5000000 { + compatible = "arm,mmu-500"; + #iommu-cells = <1>; + stream-match-mask = <0x7C00>; + ... + }; + fsl_mc: fsl-mc at 80c000000 { compatible = "fsl,qoriq-mc"; reg = <0x00000008 0x0c000000 0 0x40>, /* MC portal base */ <0x00000000 0x08340000 0 0x40000>; /* MC control reg */ msi-parent = <&its>; + iommu-parent = <&smmu>; #address-cells = <3>; #size-cells = <1>;