> -----Original Message----- > From: Robin Murphy [mailto:robin.murphy@xxxxxxx] > Sent: Monday, March 05, 2018 20:23 > To: Nipun Gupta <nipun.gupta@xxxxxxx>; will.deacon@xxxxxxx; > mark.rutland@xxxxxxx; catalin.marinas@xxxxxxx > Cc: iommu@xxxxxxxxxxxxxxxxxxxxxxxxxx; robh+dt@xxxxxxxxxx; hch@xxxxxx; > m.szyprowski@xxxxxxxxxxx; gregkh@xxxxxxxxxxxxxxxxxxx; joro@xxxxxxxxxx; > Leo Li <leoyang.li@xxxxxxx>; shawnguo@xxxxxxxxxx; linux- > kernel@xxxxxxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx; linux-arm- > kernel@xxxxxxxxxxxxxxxxxxx; linuxppc-dev@xxxxxxxxxxxxxxxx; Bharat Bhushan > <bharat.bhushan@xxxxxxx>; stuyoder@xxxxxxxxx; Laurentiu Tudor > <laurentiu.tudor@xxxxxxx> > Subject: Re: [PATCH 1/6] Docs: dt: add fsl-mc iommu-parent device-tree binding > > 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"? Hi Robin, With 'msi-parent' the property is fixed up to have msi-map. In this case there is no fixup required and simple 'iommu-parent' property can be used, with MC bus itself providing the stream-id's (in the code execution via FW). We can also use the iommu-map property similar to PCI, which will require u-boot fixup. But then it leads to little bit complications of u-boot - kernel compatibility. If you suggest we can re-use the iommu-map property. What is your opinion? Thanks, Nipun > > > Signed-off-by: Nipun Gupta <nipun.gupta@xxxxxxx> > > --- > > .../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. > > > +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@5000000 { > > + compatible = "arm,mmu-500"; > > + #iommu-cells = <1>; > > + 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>; > > + iommu-parent = <&smmu>; > > #address-cells = <3>; > > #size-cells = <1>; > > > > ��.n��������+%������w��{.n����z�{��ܨ}���Ơz�j:+v�����w����ޙ��&�)ߡ�a����z�ޗ���ݢj��w�f
