RE: [PATCH 1/7 v5] Docs: dt: add fsl-mc iommu-map device-tree binding

[Nipun Gupta]

> -----Original Message-----
> From: Robin Murphy [mailto:robin.murphy@xxxxxxx]
> Sent: Tuesday, July 3, 2018 8:10 PM
> To: Nipun Gupta <nipun.gupta@xxxxxxx>; will.deacon@xxxxxxx;
> robh+dt@xxxxxxxxxx; robh@xxxxxxxxxx; mark.rutland@xxxxxxx;
> catalin.marinas@xxxxxxx; gregkh@xxxxxxxxxxxxxxxxxxx; Laurentiu Tudor
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> Cc: hch@xxxxxx; joro@xxxxxxxxxx; m.szyprowski@xxxxxxxxxxx;
> shawnguo@xxxxxxxxxx; frowand.list@xxxxxxxxx; iommu@xxxxxxxxxxxx
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> Subject: Re: [PATCH 1/7 v5] Docs: dt: add fsl-mc iommu-map device-tree
> binding
> 
> On 20/05/18 14:49, Nipun Gupta wrote:
> > 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>
> > Reviewed-by: Rob Herring <robh@xxxxxxxxxx>
> > ---
> >   .../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
> 
> Nit: Looks like that's Documentation/networking/dpaa2/overview.rst now.
> 
> > +
> > +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>;
> 
> This should be 1 if stream-match-mask is present. Bad example is bad :)

Agree :). Ill update it.

> 
> Robin.
> 
> > +               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>;
> >
> >