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

Rob Herring
2024-10-10T02:49:23Z

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.

> + 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.

Rob