linux-kernel - Re: [PATCH v2 06/10] dt-bindings: gpu: mali-bifrost: Add a compatible for MediaTek MT8186

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Date:   Thu, 23 Feb 2023 10:43:50 +0800
From:   Chen-Yu Tsai <wenst@...omium.org>
To:     AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...labora.com>
Cc:     airlied@...il.com, daniel@...ll.ch, robh+dt@...nel.org,
        krzysztof.kozlowski+dt@...aro.org, steven.price@....com,
        alyssa.rosenzweig@...labora.com, matthias.bgg@...il.com,
        robh@...nel.org, 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
Subject: Re: [PATCH v2 06/10] dt-bindings: gpu: mali-bifrost: Add a compatible
 for MediaTek MT8186

On Wed, Feb 22, 2023 at 5:13 PM AngeloGioacchino Del Regno
<angelogioacchino.delregno@...labora.com> wrote:
>
> Il 22/02/23 09:37, Chen-Yu Tsai ha scritto:
> > On Tue, Feb 21, 2023 at 11:37 PM AngeloGioacchino Del Regno
> > <angelogioacchino.delregno@...labora.com> wrote:
> >>
> >> Get GPU support on MT8186 by adding its compatible.
> >>
> >> Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>
> >> ---
> >>   Documentation/devicetree/bindings/gpu/arm,mali-bifrost.yaml | 5 +++++
> >>   1 file changed, 5 insertions(+)
> >>
> >> diff --git a/Documentation/devicetree/bindings/gpu/arm,mali-bifrost.yaml b/Documentation/devicetree/bindings/gpu/arm,mali-bifrost.yaml
> >> index be18b161959b..43a841d4e94d 100644
> >> --- a/Documentation/devicetree/bindings/gpu/arm,mali-bifrost.yaml
> >> +++ b/Documentation/devicetree/bindings/gpu/arm,mali-bifrost.yaml
> >> @@ -15,6 +15,11 @@ properties:
> >>
> >>     compatible:
> >>       oneOf:
> >> +      - items:
> >> +          - enum:
> >> +              - mediatek,mt8186-mali
> >> +          - const: mediatek,mt8183b-mali
> >> +          - const: arm,mali-bifrost # Mali Bifrost GPU model/revision is fully discoverable
> >
> > The MT8186 has Mali-G52 MC2 2EE, while the MT8183 has Mali-G72 MP3.
>
> Keeping in mind the obvious - which is that G52 and G72 are both Bifrost....
>
> > So we actually need a new entry with two power domains.
> >
>
> ...This is my node for MT8186:
>
>                 gpu: gpu@...40000 {
>                         compatible = "mediatek,mt8186-mali",
>                                      "mediatek,mt8183b-mali",
>                                      "arm,mali-bifrost";
>                         reg = <0 0x13040000 0 0x4000>;
>
>                         clocks = <&mfgsys CLK_MFG_BG3D>;
>                         interrupts = <GIC_SPI 276 IRQ_TYPE_LEVEL_HIGH 0>,
>                                      <GIC_SPI 275 IRQ_TYPE_LEVEL_HIGH 0>,
>                                      <GIC_SPI 274 IRQ_TYPE_LEVEL_HIGH 0>;
>                         interrupt-names = "job", "mmu", "gpu";
>                         power-domains = <&spm MT8186_POWER_DOMAIN_MFG1>,
>                                         <&spm MT8186_POWER_DOMAIN_MFG2>,
>                                         <&spm MT8186_POWER_DOMAIN_MFG3>;
>                         power-domain-names = "core0", "core1", "core2";
>
>                         /* Please ignore speedbin, that's for another time :-) */
>                         nvmem-cells = <&gpu_volt_bin>;
>                         nvmem-cell-names = "speed-bin";
>                         #cooling-cells = <2>;
>                 };
>
> There are three MFG power domains... MFG2 and MFG3 are parents of MFG1, on that
> I agree, but we can avoid adding a new entry just for MT8186 and use the MT8183-b
> one while still being technically correct.
>
> Besides, Mali G52 and Mali G72 are both Bifrost... so I don't think that this
> commit is incorrect. For the sake of simplicity, I would push on getting this
> one picked.

I'm aware. In case it wasn't obvious, Mali-G52 MC2 2EE has 2 cores, while
Mali-G72 MP3 has 3 cores. I think that is reason enough to do a new entry.
Otherwise you are describing power domains for 3 cores for a GPU that only
has two.

> Unless there are any real-strong opinions against...

Yes.

ChenYu