Re: [PATCH v2 03/14] dt-bindings: pci: Add common schema for devices accessible through PCI BARs

[Andrea della Porta <andrea.porta@xxxxxxxx>]

Hi Rob,

On 21:47 Wed 09 Oct     , Rob Herring wrote:
> On Mon, Oct 07, 2024 at 02:39:46PM +0200, Andrea della Porta wrote:
> > Common YAML schema for devices that exports internal peripherals through
> > PCI BARs. The BARs are exposed as simple-buses through which the
> > peripherals can be accessed.
> > 
> > This is not intended to be used as a standalone binding, but should be
> > included by device specific bindings.
> > 
> > Signed-off-by: Andrea della Porta <andrea.porta@xxxxxxxx>
> > ---
> >  .../devicetree/bindings/pci/pci-ep-bus.yaml   | 69 +++++++++++++++++++
> >  MAINTAINERS                                   |  1 +
> >  2 files changed, 70 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/pci/pci-ep-bus.yaml
> > 
> > diff --git a/Documentation/devicetree/bindings/pci/pci-ep-bus.yaml b/Documentation/devicetree/bindings/pci/pci-ep-bus.yaml
> > new file mode 100644
> > index 000000000000..9d7a784b866a
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/pci/pci-ep-bus.yaml
> > @@ -0,0 +1,69 @@
> > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/pci/pci-ep-bus.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: Common properties for PCI MFD endpoints with peripherals addressable from BARs.
> > +
> > +maintainers:
> > +  - Andrea della Porta  <andrea.porta@xxxxxxxx>
> > +
> > +description:
> > +  Define a generic node representing a PCI endpoint which contains several sub-
> > +  peripherals. The peripherals can be accessed through one or more BARs.
> > +  This common schema is intended to be referenced from device tree bindings, and
> > +  does not represent a device tree binding by itself.
> > +
> > +properties:
> > +  "#address-cells":
> > +    const: 3
> > +
> > +  "#size-cells":
> > +    const: 2
> > +
> > +  ranges:
> > +    minItems: 1
> > +    maxItems: 6
> > +    items:
> > +      maxItems: 8
> > +      additionalItems: true
> > +      items:
> > +        - maximum: 5  # The BAR number
> > +        - const: 0
> > +        - const: 0
> > +
> > +patternProperties:
> > +  "^pci-ep-bus@[0-5]$":
> > +    $ref: '#/$defs/pci-ep-bus'
> 
> This should just be:
> 
> additionalProperties: true
> 
> properties:
>   compatible:
>     const: simple-bus
> 
> required:
>   - compatible
> 
> Then the compatible will cause simple-bus.yaml to be applied to this 
> node.
>

Ack.
 
> > +    description:
> > +      One node for each BAR used by peripherals contained in the PCI endpoint.
> > +      Each node represent a bus on which peripherals are connected.
> > +      This allows for some segmentation, e.g. one peripheral is accessible
> > +      through BAR0 and another through BAR1, and you don't want the two
> > +      peripherals to be able to act on the other BAR. Alternatively, when
> > +      different peripherals need to share BARs, you can define only one node
> > +      and use 'ranges' property to map all the used BARs.
> > +
> > +required:
> > +  - ranges
> > +  - '#address-cells'
> > +  - '#size-cells'
> > +
> > +$defs:
> > +  pci-ep-bus:
> > +    type: object
> > +    additionalProperties: true
> > +    properties:
> > +      compatible:
> > +        const: simple-bus
> > +      dma-ranges: true
> > +      ranges: true
> > +      "#address-cells": true
> > +      "#size-cells": true
> > +    required:
> > +      - compatible
> > +      - ranges
> > +      - '#address-cells'
> > +      - '#size-cells'
> 
> All this should be covered by simple-bus.yaml.

Ack.

Many thanks,
Andrea
> 
> Rob