Re: [PATCH 00/16] dts/dt-bindings: Fix Arm Ltd. ARMv8 "boards"

[Robin Murphy <robin.murphy@arm.com>]

On 2020-05-05 5:51 pm, Andre Przywara wrote:
> Date: Mon, 4 May 2020 12:41:55 +0100
> Subject: [PATCH 01/16] dt-bindings: mali-midgard: Allow dma-coherent
> 
> Add the boolean dma-coherent property to the list of allowed properties,
> since some boards (Arm Juno) integrate the GPU this way.

The same comment as for "iommus" applies to some degree here too. 
There's a bit more likelihood that the device itself does want to know 
whether it's integrated coherently, so that it can choose what memory 
attributes to use (as is the case here), but with protocols like 
ACE-lite it's possible to hard-wire any old dumb device to behave 
coherently without even realising. Thus this is another property that 
could legitimately turn up more or less anywhere.

Robin.

> Signed-off-by: Andre Przywara <andre.przywara@arm.com>
> ---
>   Documentation/devicetree/bindings/gpu/arm,mali-midgard.yaml | 2 ++
>   1 file changed, 2 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/gpu/arm,mali-midgard.yaml b/Documentation/devicetree/bindings/gpu/arm,mali-midgard.yaml
> index 0407e45eb8c4..5d7165385e1f 100644
> --- a/Documentation/devicetree/bindings/gpu/arm,mali-midgard.yaml
> +++ b/Documentation/devicetree/bindings/gpu/arm,mali-midgard.yaml
> @@ -87,6 +87,8 @@ properties:
>     "#cooling-cells":
>       const: 2
>   
> +  dma-coherent: true
> +
>   required:
>     - compatible
>     - reg
>