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

Andrea della Porta
2024-10-22T09:16:24Z

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@suse.com>
> > ---
> > .../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@suse.com>
> > +
> > +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