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Date:   Wed, 6 Dec 2023 09:09:27 -0600
From:   Rob Herring <robh@kernel.org>
To:     Tanmay Shah <tanmay.shah@amd.com>
Cc:     jassisinghbrar@gmail.com, krzysztof.kozlowski+dt@linaro.org,
        conor+dt@kernel.org, shubhrajyoti.datta@amd.com,
        michal.simek@amd.com, linux-kernel@vger.kernel.org,
        devicetree@vger.kernel.org, ben.levinsky@amd.com
Subject: Re: [PATCH] dt-bindings: mailbox: add Versal IPI bindings
Message-ID: <20231206150927.GA2140113-robh@kernel.org>
References: <20231130011936.3753814-1-tanmay.shah@amd.com>
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On Wed, Nov 29, 2023 at 05:19:36PM -0800, Tanmay Shah wrote:
> Add documentation for AMD-Xilinx Versal platform Inter Processor Interrupt
> controller. These bindings are different from previous
> xlnx,zynqmp-ipi-mailbox bindings and hence introduced in separate file.
> However, same existing driver will be extended for devices that are based
> on Versal bindings.

Looks to me like the binding doc could be shared.

> 
> Signed-off-by: Tanmay Shah <tanmay.shah@amd.com>
> ---
>  .../mailbox/xlnx,versal-ipi-mailbox.yaml      | 174 ++++++++++++++++++
>  1 file changed, 174 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/mailbox/xlnx,versal-ipi-mailbox.yaml
> 
> diff --git a/Documentation/devicetree/bindings/mailbox/xlnx,versal-ipi-mailbox.yaml b/Documentation/devicetree/bindings/mailbox/xlnx,versal-ipi-mailbox.yaml
> new file mode 100644
> index 000000000000..4408b59d392d
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/mailbox/xlnx,versal-ipi-mailbox.yaml
> @@ -0,0 +1,174 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/mailbox/xlnx,versal-ipi-mailbox.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Xilinx IPI(Inter Processor Interrupt) mailbox controller
> +
> +description: |
> +  The Xilinx IPI(Inter Processor Interrupt) mailbox controller is to manage
> +  messaging between two IPI agents. Each IPI agent owns registers used for
> +  notification and buffers for message.
> +
> +               +-------------------------------------+
> +               | Xilinx IPI Controller               |
> +               +-------------------------------------+
> +    +--------------------------------------------------+
> +  TF-A                   |                     |
> +                         |                     |
> +                         |                     |
> +    +--------------------------+               |
> +                         |                     |
> +                         |                     |
> +    +--------------------------------------------------+
> +              +------------------------------------------+
> +              |  +----------------+   +----------------+ |
> +  Hardware    |  |  IPI Agent     |   |  IPI Buffers   | |
> +              |  |  Registers     |   |  (optional)    | |
> +              |  |                |   |                | |
> +              |  +----------------+   +----------------+ |
> +              |                                          |
> +              | Xilinx IPI Agent Block                   |
> +              +------------------------------------------+
> +
> +maintainers:
> +  - Shubhrajyoti Datta <shubhrajyoti.datta@amd.com>
> +
> +properties:
> +  compatible:
> +    const: xlnx,versal-ipi-mailbox
> +
> +  method:
> +    description: |
> +      The method of calling the PM-API firmware layer.
> +      Permitted values are.
> +      - "smc" : SMC
> +      - "hvc" : HVC

The schema already says this, no need to do so twice.

> +
> +    $ref: /schemas/types.yaml#/definitions/string
> +    enum:
> +      - smc
> +      - hvc
> +    default: smc
> +
> +  '#address-cells':
> +    const: 2
> +
> +  '#size-cells':
> +    const: 2
> +
> +  reg:
> +    minItems: 1
> +    items:
> +      - description: Host IPI agent control registers
> +      - description: Host IPI agent optional message buffers
> +
> +  reg-names:
> +    minItems: 1
> +    items:
> +      - const: ctrl
> +      - const: msg
> +
> +  xlnx,ipi-id:
> +    description: |
> +      Remote Xilinx IPI agent ID of which the mailbox is connected to.
> +    $ref: /schemas/types.yaml#/definitions/uint32

Any value 0-2^32 is valid?

Place vendor properties last.

> +
> +  interrupts:
> +    maxItems: 1
> +
> +  ranges: true
> +
> +patternProperties:
> +  '^mailbox@[0-9a-f]+$':
> +    description: Internal ipi mailbox node
> +    type: object
> +
> +    properties:
> +
> +      compatible:
> +        const: xlnx,versal-ipi-dest-mailbox
> +
> +      xlnx,ipi-id:
> +        description:
> +          Remote Xilinx IPI agent ID of which the mailbox is connected to.
> +        $ref: /schemas/types.yaml#/definitions/uint32

Any value 0-2^32 is valid?

> +
> +      '#mbox-cells':
> +        const: 1
> +        description:
> +          It contains tx(0) or rx(1) channel IPI id number.
> +
> +      reg:
> +        minItems: 1
> +        items:
> +          - description: Host IPI agent control registers
> +          - description: Host IPI agent optional message buffers

Same description as the parent? But the parent is not a mailbox (No 
#mbox-cells)? 

> +
> +      reg-names:
> +        minItems: 1
> +        items:
> +          - const: ctrl
> +          - const: msg
> +
> +    additionalProperties: false
> +
> +    required:
> +      - compatible
> +      - reg
> +      - reg-names
> +      - xlnx,ipi-id
> +      - "#mbox-cells"
> +
> +additionalProperties: false
> +
> +required:
> +  - compatible
> +  - interrupts
> +  - '#address-cells'
> +  - '#size-cells'
> +  - reg
> +  - reg-names
> +  - xlnx,ipi-id

Same order as 'properties'.

> +
> +examples:
> +  - |
> +    #include<dt-bindings/interrupt-controller/arm-gic.h>
> +
> +    amba {

bus {

> +      #address-cells = <0x2>;
> +      #size-cells = <0x2>;
> +      zynqmp-mailbox@ff300000 {
> +        compatible = "xlnx,versal-ipi-mailbox";
> +        interrupts = <GIC_SPI 29 IRQ_TYPE_LEVEL_HIGH>;
> +        xlnx,ipi-id = <0>;
> +        #address-cells = <2>;
> +        #size-cells = <2>;
> +        reg = <0x0 0xff300000 0x0 0x1000>,
> +              <0x0 0xff990000 0x0 0x1ff>;
> +        reg-names = "ctrl", "msg";
> +        ranges;
> +
> +        /* buffered IPI */
> +        mailbox@ff340000 {
> +          compatible = "xlnx,versal-ipi-dest-mailbox";
> +          reg = <0x0 0xff340000 0x0 0x1000>,
> +                <0x0 0xff990400 0x0 0x1ff>;
> +          reg-names = "ctrl", "msg";
> +          #mbox-cells = <1>;
> +          xlnx,ipi-id = <4>;
> +        };
> +
> +        /* bufferless IPI */
> +        mailbox@ff370000 {
> +          compatible = "xlnx,versal-ipi-dest-mailbox";
> +          reg = <0x0 0xff370000 0x0 0x1000>;
> +          reg-names = "ctrl";
> +          #mbox-cells = <1>;
> +          xlnx,ipi-id = <7>;
> +        };
> +      };
> +    };
> +
> +...
> 
> base-commit: 2cc14f52aeb78ce3f29677c2de1f06c0e91471ab
> -- 
> 2.25.1
>