Re: [PATCH v9 4/5] dt-bindings: riscv: Add binding for CBQRI controllers

[Conor Dooley]

On Sat, Oct 03, 2026 at 12:12:29AM -0700, Drew Fustini wrote:
> Document the device tree binding for RISC-V CBQRI capacity and bandwidth
> controllers. Each controller is named by a device-specific compatible
> followed by the generic compatible. The binding also describes the
> common riscv,cbqri-rcid and riscv,cbqri-mcid properties, and the
> optional riscv,cbqri-cache phandle that links a capacity controller to
> the cache whose capacity it allocates.
> 
> Assisted-by: LLM
> Reviewed-by: Conor Dooley <conor.dooley@xxxxxxxxxxxxx>
> Co-developed-by: Adrien Ricciardi <aricciardi@xxxxxxxxxxxx>
> Signed-off-by: Adrien Ricciardi <aricciardi@xxxxxxxxxxxx>
> Signed-off-by: Drew Fustini <fustini@xxxxxxxxxx>
> ---
>  .../devicetree/bindings/riscv/riscv,cbqri.yaml     | 97 ++++++++++++++++++++++
>  MAINTAINERS                                        |  1 +
>  2 files changed, 98 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/riscv/riscv,cbqri.yaml b/Documentation/devicetree/bindings/riscv/riscv,cbqri.yaml
> new file mode 100644
> index 000000000000..0924758ebdde
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/riscv/riscv,cbqri.yaml
> @@ -0,0 +1,97 @@
> +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/riscv/riscv,cbqri.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: RISC-V Capacity and Bandwidth QoS Register Interface (CBQRI) controller
> +
> +description: |
> +  The RISC-V CBQRI specification defines capacity-controller and
> +  bandwidth-controller register blocks that allocate cache capacity and memory
> +  bandwidth to resource-control IDs (RCIDs) and monitor usage per
> +  monitoring-counter ID (MCID):
> +  https://github.com/riscv-non-isa/riscv-cbqri/blob/main/riscv-cbqri.pdf
> +
> +  Allocation and monitoring share one register block, and a controller may
> +  implement either or both. A driver discovers which at runtime from the
> +  capabilities register, so the compatible names only the controller type. It
> +  does not distinguish allocation-only, monitoring-only or combined
> +  controllers, and no property declares monitoring support.
> +
> +maintainers:
> +  - Drew Fustini <fustini@xxxxxxxxxx>
> +
> +properties:
> +  compatible:
> +    oneOf:
> +      - items:
> +          - enum:
> +              - tenstorrent,ascalon-shared-cache-controller
> +          - const: riscv,cbqri-capacity-controller
> +      - items:
> +          - {}
> +          - const: riscv,cbqri-bandwidth-controller

I think I lead you up the garden path here actually, it needs to be
"- not: {}", "- {}" permits anything.

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