linux-hardening - Re: [PATCH v8 1/5] dt-bindings: gpu: mali-valhall-csf: add mediatek,mt8196-mali variant

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Message-ID: <aQD5gwByEmX6GQK9@e110455-lin.cambridge.arm.com>
Date: Tue, 28 Oct 2025 17:12:35 +0000
From: Liviu Dudau <liviu.dudau@....com>
To: Nicolas Frattaroli <nicolas.frattaroli@...labora.com>
Cc: AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>,
	Boris Brezillon <boris.brezillon@...labora.com>,
	Jassi Brar <jassisinghbrar@...il.com>,
	Chia-I Wu <olvaffe@...il.com>, Chen-Yu Tsai <wenst@...omium.org>,
	Steven Price <steven.price@....com>,
	Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
	Maxime Ripard <mripard@...nel.org>,
	Thomas Zimmermann <tzimmermann@...e.de>,
	David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>,
	Rob Herring <robh@...nel.org>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>,
	Matthias Brugger <matthias.bgg@...il.com>,
	Kees Cook <kees@...nel.org>,
	"Gustavo A. R. Silva" <gustavoars@...nel.org>,
	Ulf Hansson <ulf.hansson@...aro.org>, kernel@...labora.com,
	dri-devel@...ts.freedesktop.org, devicetree@...r.kernel.org,
	linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
	linux-mediatek@...ts.infradead.org, linux-hardening@...r.kernel.org,
	linux-pm@...r.kernel.org
Subject: Re: [PATCH v8 1/5] dt-bindings: gpu: mali-valhall-csf: add
 mediatek,mt8196-mali variant

On Fri, Oct 17, 2025 at 05:31:08PM +0200, Nicolas Frattaroli wrote:
> The Mali-based GPU on the MediaTek MT8196 SoC uses a separate MCU to
> control the power and frequency of the GPU. This is modelled as a power
> domain and clock provider.
> 
> It lets us omit the OPP tables from the device tree, as those can now be
> enumerated at runtime from the MCU.
> 
> Add the necessary schema logic to handle what this SoC expects in terms
> of clocks and power-domains.
> 
> Reviewed-by: Rob Herring (Arm) <robh@...nel.org>
> Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>
> Signed-off-by: Nicolas Frattaroli <nicolas.frattaroli@...labora.com>
> ---
>  .../bindings/gpu/arm,mali-valhall-csf.yaml         | 37 +++++++++++++++++++++-
>  1 file changed, 36 insertions(+), 1 deletion(-)
> 
> diff --git a/Documentation/devicetree/bindings/gpu/arm,mali-valhall-csf.yaml b/Documentation/devicetree/bindings/gpu/arm,mali-valhall-csf.yaml
> index 613040fdb444..860691ce985e 100644
> --- a/Documentation/devicetree/bindings/gpu/arm,mali-valhall-csf.yaml
> +++ b/Documentation/devicetree/bindings/gpu/arm,mali-valhall-csf.yaml
> @@ -45,7 +45,9 @@ properties:
>      minItems: 1
>      items:
>        - const: core
> -      - const: coregroup
> +      - enum:
> +          - coregroup
> +          - stacks
>        - const: stacks

I'm not sure how to parse this part of the change. We're overwriting the property
for mt8196-mali anyway so why do we need this? And if we do, should 'stacks'
still remain as a const?

Best regards,
Liviu

>  
>    mali-supply: true
> @@ -110,6 +112,27 @@ allOf:
>          power-domain-names: false
>        required:
>          - mali-supply
> +  - if:
> +      properties:
> +        compatible:
> +          contains:
> +            const: mediatek,mt8196-mali
> +    then:
> +      properties:
> +        mali-supply: false
> +        sram-supply: false
> +        operating-points-v2: false
> +        power-domains:
> +          maxItems: 1
> +        power-domain-names: false
> +        clocks:
> +          maxItems: 2
> +        clock-names:
> +          items:
> +            - const: core
> +            - const: stacks
> +      required:
> +        - power-domains
>  
>  examples:
>    - |
> @@ -145,5 +168,17 @@ examples:
>              };
>          };
>      };
> +  - |
> +    gpu@...00000 {
> +        compatible = "mediatek,mt8196-mali", "arm,mali-valhall-csf";
> +        reg = <0x48000000 0x480000>;
> +        clocks = <&gpufreq 0>, <&gpufreq 1>;
> +        clock-names = "core", "stacks";
> +        interrupts = <GIC_SPI 606 IRQ_TYPE_LEVEL_HIGH 0>,
> +                     <GIC_SPI 605 IRQ_TYPE_LEVEL_HIGH 0>,
> +                     <GIC_SPI 604 IRQ_TYPE_LEVEL_HIGH 0>;
> +        interrupt-names = "job", "mmu", "gpu";
> +        power-domains = <&gpufreq>;
> +    };
>  
>  ...
> 
> -- 
> 2.51.0
> 

-- 
====================
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| but they're not |
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