On 5/22/2020 12:42 PM, Robin Murphy wrote:
On 2020-05-22 00:10, Rob Herring wrote:On Thu, May 21, 2020 at 7:00 AM Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx> wrote:From: Laurentiu Tudor <laurentiu.tudor@xxxxxxx> The existing bindings cannot be used to specify the relationship between fsl-mc devices and GIC ITSes. Add a generic binding for mapping fsl-mc devices to GIC ITSes, using msi-map property. Signed-off-by: Laurentiu Tudor <laurentiu.tudor@xxxxxxx> Cc: Rob Herring <robh+dt@xxxxxxxxxx> ---.../devicetree/bindings/misc/fsl,qoriq-mc.txt | 30 +++++++++++++++++--1 file changed, 27 insertions(+), 3 deletions(-)diff --git a/Documentation/devicetree/bindings/misc/fsl,qoriq-mc.txt b/Documentation/devicetree/bindings/misc/fsl,qoriq-mc.txtindex 9134e9bcca56..b0813b2d0493 100644 --- a/Documentation/devicetree/bindings/misc/fsl,qoriq-mc.txt +++ b/Documentation/devicetree/bindings/misc/fsl,qoriq-mc.txt@@ -18,9 +18,9 @@ same hardware "isolation context" and a 10-bit value called an ICIDthe 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.+between ICIDs and IOMMUs, so the iommu-map and msi-map properties are used +to define the set of possible ICIDs under a root DPRC and how they map to+an IOMMU and a GIC ITS respectively. For generic IOMMU bindings, see Documentation/devicetree/bindings/iommu/iommu.txt. @@ -28,6 +28,9 @@ Documentation/devicetree/bindings/iommu/iommu.txt. For arm-smmu binding, see: Documentation/devicetree/bindings/iommu/arm,smmu.yaml. +For GICv3 and GIC ITS bindings, see:+Documentation/devicetree/bindings/interrupt-controller/arm,gic-v3.yaml.+ Required properties: - compatible @@ -119,6 +122,15 @@ Optional properties: associated with the listed IOMMU, with the iommu-specifier (i - icid-base + iommu-base). +- msi-map: Maps an ICID to a GIC ITS and associated iommu-specifier + data. + + The property is an arbitrary number of tuples of + (icid-base,iommu,iommu-base,length).I'm confused because the example has GIC ITS phandle, not an IOMMU. What is an iommu-base?Right, I was already halfway through writing a reply to say that all the copy-pasted "iommu" references here should be using the terminology from the pci-msi.txt binding instead.
Right, will change it.
+ + Any ICID in the interval [icid-base, icid-base + length) is + associated with the listed GIC ITS, with the iommu-specifier + (i - icid-base + iommu-base). Example: smmu: iommu@5000000 { @@ -128,6 +140,16 @@ Example: ... }; + gic: interrupt-controller@6000000 { + compatible = "arm,gic-v3"; + ... + its: gic-its@6020000 { + compatible = "arm,gic-v3-its"; + msi-controller; + ... + }; + }; + fsl_mc: fsl-mc@80c000000 { compatible = "fsl,qoriq-mc";reg = <0x00000008 0x0c000000 0 0x40>, /* MC portal base */@@ -135,6 +157,8 @@ Example: msi-parent = <&its>;Side note: is it right to keep msi-parent here? It rather implies that the MC itself has a 'native' Device ID rather than an ICID, which I believe is not strictly true. Plus it's extra-confusing that it doesn't specify an ID either way, since that makes it look like the legacy PCI case that gets treated implicitly as an identity msi-map, which makes no sense at all to combine with an actual msi-map.
Before adding msi-map, the fsl-mc code assumed that ICID and streamID are equal and used msi-parent just to get the reference to the ITS node. Removing msi-parent will break the backward compatibility of the already existing systems. Maybe we should mention that this is legacy and not to be used for newer device trees.
/* define map for ICIDs 23-64 */ iommu-map = <23 &smmu 23 41>; + /* define msi map for ICIDs 23-64 */ + msi-map = <23 &its 23 41>;Seeing 23 twice is odd. The numbers to the right of 'its' should be an ITS number space.On about 99% of systems the values in the SMMU Stream ID and ITS Device ID spaces are going to be the same. Nobody's going to bother carrying *two* sets of sideband data across the interconnect if they don't have to ;)Robin.
Diana
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