Re: [RFC PATCH v2 10/17] dt-bindings: interrupt-controller: Add bindings for RISC-V RPMI system MSI

[Rob Herring]

On Mon, Feb 03, 2025 at 02:18:59PM +0530, Anup Patel wrote:
> Add device tree bindings for the system MSI service group based interrupt
> controller defined by the RISC-V platform management interface (RPMI)
> specification.
> 
> Signed-off-by: Anup Patel <apatel@xxxxxxxxxxxxxxxx>
> ---
>  .../riscv,rpmi-system-msi.yaml                | 89 +++++++++++++++++++
>  1 file changed, 89 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/interrupt-controller/riscv,rpmi-system-msi.yaml
> 
> diff --git a/Documentation/devicetree/bindings/interrupt-controller/riscv,rpmi-system-msi.yaml b/Documentation/devicetree/bindings/interrupt-controller/riscv,rpmi-system-msi.yaml
> new file mode 100644
> index 000000000000..e6c297e66c99
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/interrupt-controller/riscv,rpmi-system-msi.yaml
> @@ -0,0 +1,89 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/interrupt-controller/riscv,rpmi-system-msi.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: RISC-V RPMI system MSI service group based interrupt controller
> +
> +maintainers:
> +  - Anup Patel <anup@xxxxxxxxxxxxxx>
> +
> +description: |
> +  The RISC-V Platform Management Interface (RPMI) [1] defines a
> +  messaging protocol which is modular and extensible. The supervisor
> +  software can send/receive RPMI messages via SBI MPXY extension [2]
> +  or some dedicated supervisor-mode RPMI transport.
> +
> +  The RPMI specification [1] defines system MSI service group which
> +  allow application processors to receive MSIs upon system events
> +  such as P2A doorbell, graceful shutdown/reboot request, CPU hotplug
> +  event, memory hotplug event, etc from the platform microcontroller.

I'm confused by this description and what the binding has. This "device" 
is receiving interrupts and generating MSIs based on those interrupts? 

> +
> +  ===========================================
> +  References
> +  ===========================================
> +
> +  [1] RISC-V Platform Management Interface (RPMI)
> +      https://github.com/riscv-non-isa/riscv-rpmi/releases
> +
> +  [2] RISC-V Supervisor Binary Interface (SBI)
> +      https://github.com/riscv-non-isa/riscv-sbi-doc/releases
> +
> +allOf:
> +  - $ref: /schemas/interrupt-controller.yaml#
> +
> +properties:
> +  compatible:
> +    oneOf:
> +      - description:
> +          Intended for use by the SBI implementation in machine mode or
> +          software in supervisor mode.
> +        const: riscv,rpmi-system-msi
> +
> +      - description:
> +          Intended for use by the SBI implementation in machine mode.
> +        const: riscv,rpmi-mpxy-system-msi
> +
> +  mboxes:
> +    maxItems: 1
> +    description:
> +      Mailbox channel of the underlying RPMI transport or SBI message proxy.
> +
> +  riscv,sbi-mpxy-channel-id:
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    description:
> +      The SBI MPXY channel id to be used for providing RPMI access to
> +      the supervisor software. This property is mandatory when using
> +      riscv,rpmi-mpxy-system-msi compatible string.
> +
> +  msi-parent: true
> +
> +  interrupt-controller: true
> +
> +  "#interrupt-cells":
> +    const: 1
> +
> +required:
> +  - compatible
> +  - mboxes
> +  - msi-parent
> +  - interrupt-controller
> +  - "#interrupt-cells"
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    mpxy_mbox: sbi-mpxy-mbox {

mailbox {

Though generally we don't show providers for a consumer schema.

> +          compatible = "riscv,sbi-mpxy-mbox";
> +          #mbox-cells = <2>;
> +    };
> +    rpmi_sysmsi_intc: interrupt-controller {
> +        compatible = "riscv,rpmi-system-msi";
> +        mboxes = <&mpxy_mbox 0x2000 0x0>;
> +        msi-parent = <&imsic_slevel>;
> +        interrupt-controller;
> +        #interrupt-cells = <1>;
> +    };
> +...
> -- 
> 2.43.0
>