Re: [PATCH 2/5] dt-bindings: iommu: verisilicon: Add binding for VSI IOMMU

[Benjamin Gaignard]

Le 16/06/2025 à 17:58, Conor Dooley a écrit :
> On Mon, Jun 16, 2025 at 05:50:50PM +0200, Benjamin Gaignard wrote:
> > Le 16/06/2025 à 17:42, Conor Dooley a écrit :
> > > On Mon, Jun 16, 2025 at 05:30:44PM +0200, Benjamin Gaignard wrote:
> > > > Le 16/06/2025 à 17:14, Conor Dooley a écrit :
> > > > > On Mon, Jun 16, 2025 at 04:55:50PM +0200, Benjamin Gaignard wrote:
> > > > > > Add a device tree binding for the Verisilicon (VSI) IOMMU. This IOMMU sits
> > > > > > in front of hardware encoder and decoder blocks on SoCs using Verisilicon IP,
> > > > > > such as the Rockchip RK3588.
> > > > > >
> > > > > > Signed-off-by: Benjamin Gaignard <benjamin.gaignard@xxxxxxxxxxxxx>
> > > > > > ---
> > > > > >     .../bindings/iommu/verisilicon,iommu.yaml     | 71 +++++++++++++++++++
> > > > > >     1 file changed, 71 insertions(+)
> > > > > >     create mode 100644 Documentation/devicetree/bindings/iommu/verisilicon,iommu.yaml
> > > > > >
> > > > > > diff --git a/Documentation/devicetree/bindings/iommu/verisilicon,iommu.yaml b/Documentation/devicetree/bindings/iommu/verisilicon,iommu.yaml
> > > > > > new file mode 100644
> > > > > > index 000000000000..acef855fc61d
> > > > > > --- /dev/null
> > > > > > +++ b/Documentation/devicetree/bindings/iommu/verisilicon,iommu.yaml
> > > > > > @@ -0,0 +1,71 @@
> > > > > > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > > > > > +%YAML 1.2
> > > > > > +---
> > > > > > +$id: http://devicetree.org/schemas/iommu/verisilicon,iommu.yaml#
> > > > > > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > > > > > +
> > > > > > +title: Verisilicon IOMMU
> > > > > > +
> > > > > > +maintainers:
> > > > > > +  - Benjamin Gaignard <benjamin.gaignard@xxxxxxxxxxxxx>
> > > > > > +
> > > > > > +description: |+
> > > > > > +  A Versilicon iommu translates io virtual addresses to physical addresses for
> > > > > > +  its associated video decoder.
> > > > > > +
> > > > > > +properties:
> > > > > > +  compatible:
> > > > > > +    oneOf:
> > > > > > +      - items:
> > > > > > +          - const: verisilicon,iommu
> > > > > You're missing a soc-specific compatible at the very least here, but is
> > > > > there really no versioning on the IP at all? I'd be surprised if
> > > > > verisilicon only produced exactly one version of an iommu IP.
> > > > I only aware this version of the iommu for the moment.
> > > "for the moment", yeah. Is there any information that could be used to
> > > version this available?
> > The hardware block isn't documented in the TRM so I don't know if there is a version
> > field or something like that.
> >
> > > > Does adding verisilicon,rk3588-iommu sound good for you ?
> > > It'd be "rockchip,rk3588-iommu", but sure.
> > "rockchip,rk3588-iommu" is already use for other MMUs in rk3588.
> "rockchip,rk3588-video-iommu" then? Instances of an IP in an SoC get a
> specific compatible with the SoC vendor's prefix, so having verisilicon
> there isn't suitable unless they made the SoC.

Other hardware video codecs have a different IOMMU so I will suggest
"rockchip,rk3588-av1-iommu" which is specific to this video hardware block.