Re: [PATCH 6/9] dt-bindings: Add RISC-V advanced PLIC bindings

[Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>]

On 11/11/2022 05:42, Anup Patel wrote:
> We add DT bindings document for RISC-V advanced platform level interrupt
> controller (APLIC) defined by the RISC-V advanced interrupt architecture
> (AIA) specification.
> 
> Signed-off-by: Anup Patel <apatel@ventanamicro.com>
> ---
>  .../interrupt-controller/riscv,aplic.yaml     | 136 ++++++++++++++++++
>  1 file changed, 136 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/interrupt-controller/riscv,aplic.yaml
> 
> diff --git a/Documentation/devicetree/bindings/interrupt-controller/riscv,aplic.yaml b/Documentation/devicetree/bindings/interrupt-controller/riscv,aplic.yaml
> new file mode 100644
> index 000000000000..0aa48571f3bc
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/interrupt-controller/riscv,aplic.yaml
> @@ -0,0 +1,136 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/interrupt-controller/riscv,aplic.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: RISC-V Advancded Platform Level Interrupt Controller (APLIC)
> +
> +maintainers:
> +  - Anup Patel <anup@brainfault.org>
> +
> +description:
> +  The RISC-V advanced interrupt architecture (AIA) defines advanced platform
> +  level interrupt controller (APLIC) for handling wired interrupts in a
> +  RISC-V platform. The RISC-V AIA specification can be found at
> +  https://github.com/riscv/riscv-aia.
> +
> +  The RISC-V APLIC is implemented as hierarchical APLIC domains where all
> +  interrupt sources connect to the root domain which can further delegate
> +  interrupts to child domains. We have one device tree node for each APLIC
> +  domain.
> +
> +allOf:
> +  - $ref: /schemas/interrupt-controller.yaml#
> +
> +properties:
> +  compatible:
> +    items:
> +      - enum:
> +          - vendor,chip-aplic
> +      - const: riscv,aplic
> +
> +  reg:
> +    maxItems: 1
> +
> +  interrupt-controller: true
> +
> +  "#interrupt-cells":
> +    const: 2
> +
> +  interrupts-extended:
> +    minItems: 1
> +    maxItems: 16384
> +    description:
> +      The presence of this property implies that given APLIC domain directly
> +      injects external interrupts to a set of RISC-V HARTS (or CPUs). Each
> +      node pointed to should be a riscv,cpu-intc node, which has a riscv node
> +      (i.e. RISC-V HART) as parent.
> +
> +  msi-parent:
> +    description:
> +      The presence of this property implies that given APLIC domain forwards

Drop "The presence of this property" and make it a proper sentence
describing hardware.

> +      wired interrupts as MSIs to a AIA incoming message signaled interrupt
> +      controller (IMSIC). This property should be considered only when the
> +      interrupts-extended property is absent.
> +
> +  riscv,num-sources:
> +    $ref: "/schemas/types.yaml#/definitions/uint32"

Drop quotes.

> +    minimum: 1
> +    maximum: 1023
> +    description:
> +      Specifies how many wired interrupts are supported by this APLIC domain.
> +
> +  riscv,children:
> +    $ref: '/schemas/types.yaml#/definitions/phandle-array'
> +    minItems: 1
> +    maxItems: 1024
> +    description:
> +      This property represents a list of child APLIC domains for the given
> +      APLIC domain. Each child APLIC domain is assigned child index in
> +      increasing order with the first child APLIC domain assigned child
> +      index 0. The APLIC domain child index is used by firmware to delegate
> +      interrupts from the given APLIC domain to a particular child APLIC
> +      domain.
> +
> +  riscv,delegate:
> +    $ref: '/schemas/types.yaml#/definitions/phandle-array'
> +    minItems: 1
> +    maxItems: 1024
> +    description:
> +      This property represents a interrupt delegation list where each entry

Drop "This property represents".

> +      is a triple consisting of child APLIC domain phandle, first interrupt
> +      number, and last interrupt number. The firmware will configure interrupt
> +      delegation registers based on interrupt delegation list.
> +
> +additionalProperties: false

Same comments as in previous patch,

> +
> +required:
> +  - compatible
> +  - reg
> +  - interrupt-controller
> +  - "#interrupt-cells"
> +  - riscv,num-sources
> +
> +examples:
> +  - |
> +    // Example 1 (APIC domain directly injecting interrupt to HARTs):
> +
> +    aplic0: interrupt-controller@c000000 {
> +      compatible = "vendor,chip-aplic", "riscv,aplic";
> +      interrupts-extended = <&cpu1_intc 11>,
> +                            <&cpu2_intc 11>,
> +                            <&cpu3_intc 11>,
> +                            <&cpu4_intc 11>;
> +      reg = <0xc000000 0x4080>;
> +      interrupt-controller;
> +      #interrupt-cells = <2>;
> +      riscv,num-sources = <63>;
> +      riscv,children = <&aplic1>;
> +      riscv,delegate = <&aplic1 1 63>;
> +    };
> +
> +    aplic1: interrupt-controller@d000000 {
> +      compatible = "vendor,chip-aplic", "riscv,aplic";
> +      interrupts-extended = <&cpu1_intc 9>,
> +                            <&cpu2_intc 9>,
> +                            <&cpu3_intc 9>,
> +                            <&cpu4_intc 9>;
> +      reg = <0xd000000 0x4080>;
> +      interrupt-controller;
> +      #interrupt-cells = <2>;
> +      riscv,num-sources = <63>;
> +    };
> +
> +  - |
> +    // Example 2 (APIC domain forwarding interrupts as MSIs):
> +
> +    interrupt-controller@d000000 {
> +      compatible = "vendor,chip-aplic", "riscv,aplic";
> +      msi-parent = <&imsics>;
> +      reg = <0xd000000 0x4000>;
> +      interrupt-controller;
> +      #interrupt-cells = <2>;
> +      riscv,num-sources = <63>;

It's almost the same as previous... don't add unnecessary examples
(difference in one property usually does not mean you need new example).

> +    };
> +...

Best regards,
Krzysztof