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Date:   Thu, 22 Sep 2022 22:08:56 +0100
From:   Will Deacon <will@kernel.org>
To:     Jean-Philippe Brucker <jean-philippe@linaro.org>, joro@8bytes.org
Cc:     robin.murphy@arm.com, robh+dt@kernel.org,
        krzysztof.kozlowski+dt@linaro.org,
        linux-arm-kernel@lists.infradead.org, iommu@lists.linux.dev,
        devicetree@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] dt-bindings: iommu: arm,smmu-v3: Relax order of
 interrupt names
Message-ID: <20220922210855.GC12945@willie-the-truck>
References: <20220916133145.1910549-1-jean-philippe@linaro.org>
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On Fri, Sep 16, 2022 at 02:31:47PM +0100, Jean-Philippe Brucker wrote:
> The QEMU devicetree uses a different order for SMMUv3 interrupt names,
> and there isn't a good reason for enforcing a specific order. Since all
> interrupt lines are optional, operating systems should not expect a
> fixed interrupt array layout; they should instead match each interrupt
> to its name individually. Besides, as a result of commit e4783856a2e8
> ("dt-bindings: iommu: arm,smmu-v3: make PRI IRQ optional"), "cmdq-sync"
> and "priq" are already permutable. Relax the interrupt-names array
> entirely by allowing any permutation, incidentally making the schema
> more readable.
> 
> Note that dt-validate won't allow duplicate names here so we don't need
> to specify maxItems or add additional checks, it's quite neat.
> 
> Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
> ---
>  .../devicetree/bindings/iommu/arm,smmu-v3.yaml    | 15 +++++----------
>  1 file changed, 5 insertions(+), 10 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/iommu/arm,smmu-v3.yaml b/Documentation/devicetree/bindings/iommu/arm,smmu-v3.yaml
> index c57a53d87e4e..75fcf4cb52d9 100644
> --- a/Documentation/devicetree/bindings/iommu/arm,smmu-v3.yaml
> +++ b/Documentation/devicetree/bindings/iommu/arm,smmu-v3.yaml
> @@ -39,16 +39,11 @@ properties:
>            any others.
>        - minItems: 1
>          items:
> -          - enum:
> -              - eventq     # Event Queue not empty
> -              - gerror     # Global Error activated
> -          - const: gerror
> -          - enum:
> -              - cmdq-sync  # CMD_SYNC complete
> -              - priq       # PRI Queue not empty
> -          - enum:
> -              - cmdq-sync
> -              - priq
> +          enum:
> +            - eventq      # Event Queue not empty
> +            - gerror      # Global Error activated
> +            - cmdq-sync   # CMD_SYNC complete
> +            - priq        # PRI Queue not empty
>  
>    '#iommu-cells':
>      const: 1

Acked-by: Will Deacon <will@kernel.org>

Joerg -- please can you take this one directly for 6.1? I don't actually
have any other SMMU patches queued, so it doesn't seem worth sending a pull
request just for this.

Cheers,

Will