Re: [PATCH 1/2] dt-bindings: arm: Add qcom specific hvc transport for SCMI

Krzysztof Kozlowski
2023-07-18T18:12:16Z

On 18/07/2023 18:08, Nikunj Kela wrote:
> Introduce compatible "qcom,scmi-hvc-shmem" for SCMI
> transport channel for Qualcomm virtual platforms.
> The compatible mandates a shared memory channel.
>
> Signed-off-by: Nikunj Kela <quic_nkela@quicinc.com>
> ---
> .../bindings/firmware/arm,scmi.yaml | 69 +++++++++++++++++++
> 1 file changed, 69 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/firmware/arm,scmi.yaml b/Documentation/devicetree/bindings/firmware/arm,scmi.yaml
> index b138f3d23df8..605b1e997a85 100644
> --- a/Documentation/devicetree/bindings/firmware/arm,scmi.yaml
> +++ b/Documentation/devicetree/bindings/firmware/arm,scmi.yaml
> @@ -45,6 +45,9 @@ properties:
> - description: SCMI compliant firmware with OP-TEE transport
> items:
> - const: linaro,scmi-optee
> + - description: SCMI compliant firmware with Qualcomm hvc/shmem transport
> + items:
> + - const: qcom,scmi-hvc-shmem
>
> interrupts:
> description:
> @@ -321,6 +324,16 @@ else:
> required:
> - linaro,optee-channel-id
>
> + else:
> + if:
> + properties:
> + compatible:
> + contains:
> + const: qcom,scmi-hvc-shmem
> + then:
> + required:
> + - shmem

Unfortunately this pattern if-else-if-else-if-else does not scale well.
Please convert all entries first to allOf:if:then,if:then,if:then (in
new patch), and then add new if:then:

> +
> examples:
> - |
> firmware {
> @@ -444,6 +457,62 @@ examples:
> };
> };
>
> + - |
> + firmware {
> + scmi_dpu {

No underscores in node names.

Node names should be generic. See also an explanation and list of
examples (not exhaustive) in DT specification:
https://devicetree-specification.readthedocs.io/en/latest/chapter2-devicetree-basics.html#generic-names-recommendation

> + compatible = "qcom,scmi-hvc-shmem";
> + shmem = <&shmem_dpu>;
> +
> + #address-cells = <1>;
> + #size-cells = <0>;
> +
> + scmi_pd_dpu: protocol@11 {
> + reg = <0x11>;
> + #power-domain-cells = <1>;
> + };
> + };
> +

Add only one example, but then only if it differs significantly. I see
no differences - except compatible - so maybe no point of examples.

> + scmi_gpu {
> + compatible = "qcom,scmi-hvc-shmem";
> + shmem = <&shmem_gpu>;

This example for sure is not needed - you duplicate above.

> +
> + interrupts = <GIC_SPI 931 IRQ_TYPE_EDGE_RISING>;
> + interrupt-names = "a2p";
> +
> + #address-cells = <1>;
> + #size-cells = <0>;
> +
> + scmi_pd_gpu: protocol@11 {
> + reg = <0x11>;
> + #power-domain-cells = <1>;
> + };
> + };
> + };
> +
> + soc {
> + #address-cells = <1>;
> + #size-cells = <1>;
> +
> + sram@95c00000 {
> + compatible = "mmio-sram";
> + reg = <0x95c00000 0x10000>;
> +
> + #address-cells = <1>;
> + #size-cells = <1>;
> + ranges;
> +
> + shmem_dpu: scmi-sram-dpu@95c00000 {
> + compatible = "arm,scmi-shmem";
> + reg = <0x95c00000 0x3f0>;
> + };

How does these differ from existing example?

Best regards,
Krzysztof