Re: [PATCH v3 4/8] dt-bindings: iommu: Add spacemit/t100 features

[Conor Dooley <conor@kernel.org>]

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On Wed, Feb 04, 2026 at 05:09:12PM +0800, Lv Zheng wrote:
> Adds device tree bindings for SpacemiT T100 specific features by
> introducing spacemit,100 compatible. T100 contains distributed IOATCs,
> each of which exposes pmiv interrupt.
> 
> Signed-off-by: Lv Zheng <lv.zheng@linux.spacemit.com>
> Signed-off-by: Jingyu Li <joey.li@spacemit.com>
> ---
>  .../bindings/iommu/riscv,iommu.yaml           | 37 +++++++++++++++++++
>  1 file changed, 37 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/iommu/riscv,iommu.yaml b/Documentation/devicetree/bindings/iommu/riscv,iommu.yaml
> index d4838c3b3741..2da3456e7402 100644
> --- a/Documentation/devicetree/bindings/iommu/riscv,iommu.yaml
> +++ b/Documentation/devicetree/bindings/iommu/riscv,iommu.yaml
> @@ -32,6 +32,12 @@ properties:
>    # should be specified along with 'reg' property providing MMIO location.
>    compatible:
>      oneOf:
> +      - description: SpacemiT distributed IOMMUs
> +        items:
> +          - enum:
> +              - spacemit,t100
> +          - const: spacemit,riscv-iommu

What actually is the t100? Is it an SoC or is it the name of the core
complex IP that spacemit is using in multiple SoCs?

> +          - const: riscv,iommu
>        - items:
>            - enum:
>                - qemu,riscv-iommu
> @@ -75,6 +81,23 @@ required:
>  
>  additionalProperties: false
>  
> +select: false

Why is this here? It just breaks the whole binding.
pw-bot: changes-requested

> +
> +allOf:
> +  - if:
> +      properties:
> +        compatible:
> +          contains:
> +            const: spacemit,riscv-iommu
> +    then:
> +      properties:
> +        interrupts:
> +          maxItems: 68

This isn't right. You would need to make the interrupts property itself
have maxItems: 68, then add an else to this conditional that has
maxItems: 4. What you've done just doesn't work, and if you removed the
"select: false: you'd see.

> +          description:
> +            SpacemiT distributed IOMMU includes additional interrupts for
> +            IOATCs. Each IOATC exposes pmiv wired vector as standalone
> +            interrupt and the maximum number of IOATCs can be up to 64.
> +
>  examples:
>    - |+
>      /* Example 1 (IOMMU device with wired interrupts) */
> @@ -145,3 +168,17 @@ examples:
>              };
>          };
>      };
> +
> +  - |+
> +    /* Example 5 (SpacemiT distributed IOMMU) */
> +    #include <dt-bindings/interrupt-controller/irq.h>
> +
> +    iommu4: iommu@1bccd000 {

Remove the iommu4 label, there's no references to it.

Cheers,
Conor.

> +        compatible = "spacemit,t100", "spacemit,riscv-iommu", "riscv,iommu";
> +        reg = <0x1bccd000 0x1000>;
> +        interrupts = <58 IRQ_TYPE_LEVEL_HIGH>, <58 IRQ_TYPE_LEVEL_HIGH>,
> +                     <58 IRQ_TYPE_LEVEL_HIGH>, <58 IRQ_TYPE_LEVEL_HIGH>,
> +                     <62 IRQ_TYPE_LEVEL_HIGH>, <63 IRQ_TYPE_LEVEL_HIGH>;
> +        interrupt-parent = <&saplic>;
> +        #iommu-cells = <0x01>;
> +    };
> -- 
> 2.43.0
> 

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