linux-kernel - Re: [PATCH v2 03/15] dt-bindings: display: mediatek: add EXDMA yaml for MT8196

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Message-ID: <4051e2b2249625f0e957352a4a2dfe2cf50818a4.camel@mediatek.com>
Date: Wed, 14 May 2025 16:25:30 +0000
From: Paul-pl Chen (陳柏霖) <Paul-pl.Chen@...iatek.com>
To: CK Hu (胡俊光) <ck.hu@...iatek.com>,
	"robh@...nel.org" <robh@...nel.org>, "krzk+dt@...nel.org"
	<krzk+dt@...nel.org>, "conor+dt@...nel.org" <conor+dt@...nel.org>,
	"chunkuang.hu@...nel.org" <chunkuang.hu@...nel.org>, "AngeloGioacchino Del
 Regno" <angelogioacchino.delregno@...labora.com>
CC: Sunny Shen (沈姍姍) <Sunny.Shen@...iatek.com>,
	Sirius Wang (王皓昱) <Sirius.Wang@...iatek.com>,
	Nancy Lin (林欣螢) <Nancy.Lin@...iatek.com>,
	Xiandong Wang (王先冬)
	<Xiandong.Wang@...iatek.com>, "linux-kernel@...r.kernel.org"
	<linux-kernel@...r.kernel.org>, Project_Global_Chrome_Upstream_Group
	<Project_Global_Chrome_Upstream_Group@...iatek.com>,
	"dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>,
	"linux-mediatek@...ts.infradead.org" <linux-mediatek@...ts.infradead.org>,
	Jason-JH Lin (林睿祥) <Jason-JH.Lin@...iatek.com>,
	"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
	"fshao@...omium.org" <fshao@...omium.org>, "p.zabel@...gutronix.de"
	<p.zabel@...gutronix.de>, Singo Chang (張興國)
	<Singo.Chang@...iatek.com>, "linux-arm-kernel@...ts.infradead.org"
	<linux-arm-kernel@...ts.infradead.org>, "matthias.bgg@...il.com"
	<matthias.bgg@...il.com>, "treapking@...omium.org" <treapking@...omium.org>
Subject: Re: [PATCH v2 03/15] dt-bindings: display: mediatek: add EXDMA yaml
 for MT8196

On Mon, 2025-03-24 at 02:45 +0000, CK Hu (胡俊光) wrote:
> On Fri, 2025-03-21 at 17:33 +0800, paul-pl.chen wrote:
> > From: Paul-pl Chen <paul-pl.chen@...iatek.com>
> > 
> > Add mediatek,exdma.yaml to support EXDMA for MT8196.
> > The MediaTek display overlap extended DMA engine, namely
> > OVL_EXDMA or EXDMA, primarily functions as a DMA engine
> > for reading data from DRAM with various DRAM footprints
> > and data formats.
> > 
> > Signed-off-by: Paul-pl Chen <paul-pl.chen@...iatek.com>
> > ---
> >  .../bindings/dma/mediatek,exdma.yaml          | 70
> > +++++++++++++++++++
> >  1 file changed, 70 insertions(+)
> >  create mode 100644
> > Documentation/devicetree/bindings/dma/mediatek,exdma.yaml
> > 
> > diff --git
> > a/Documentation/devicetree/bindings/dma/mediatek,exdma.yaml
> > b/Documentation/devicetree/bindings/dma/mediatek,exdma.yaml
> > new file mode 100644
> > index 000000000000..de7f8283bb48
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/dma/mediatek,exdma.yaml
> > @@ -0,0 +1,70 @@
> > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > +%YAML 1.2
> > +---
> > +$id:
> > https://urldefense.com/v3/__http://devicetree.org/schemas/dma/mediatek,exdma.yaml*__;Iw!!CTRNKA9wMg0ARbw!jH_-2I8NkTUX90vbZGjduUAo4on8DsCGFTrVX5jUdxL_zpKt5PSPRGm31otPZ4wIDzI2h9HFGbF4DC5jPw1nejo$
> >  
> > +$schema:
> > https://urldefense.com/v3/__http://devicetree.org/meta-schemas/core.yaml*__;Iw!!CTRNKA9wMg0ARbw!jH_-2I8NkTUX90vbZGjduUAo4on8DsCGFTrVX5jUdxL_zpKt5PSPRGm31otPZ4wIDzI2h9HFGbF4DC5jr1jxJoQ$
> >  
> > +
> > +title: MediaTek display overlap extended DMA engine
> > +
> > +maintainers:
> > +  - Chun-Kuang Hu <chunkuang.hu@...nel.org>
> > +  - Philipp Zabel <p.zabel@...gutronix.de>
> > +
> > +description:
> > +  The MediaTek display overlap extended DMA engine, namely
> > OVL_EXDMA or EXDMA,
> > +  primarily functions as a DMA engine for reading data from DRAM
> > with various
> > +  DRAM footprints and data formats. For input sources in certain
> > color formats
> > +  and color domains, OVL_EXDMA also includes a color transfer
> > function
> > +  to process pixels into a consistent color domain.
> > +
> > +properties:
> > +  compatible:
> > +    const: mediatek,mt8196-exdma
> > +
> > +  reg:
> > +    maxItems: 1
> > +
> > +  clocks:
> > +    maxItems: 1
> > +
> > +  power-domains:
> > +    maxItems: 1
> > +
> > +  mediatek,larb:
> > +    $ref: /schemas/types.yaml#/definitions/phandle
> > +    description: |
> > +      A phandle to the local arbiters node in the current SoCs.
> > +      Refer to bindings/memory-controllers/mediatek,smi-larb.yaml.
> > +
> > +  iommus:
> > +    maxItems: 1
> > +
> > +  '#dma-cells':
> > +    const: 1
> > +
> > +required:
> > +  - compatible
> > +  - reg
> > +  - clocks
> > +  - power-domains
> > +  - mediatek,larb
> > +
> > +additionalProperties: false
> > +
> > +examples:
> > +  - |
> > +
> > +    soc {
> > +        #address-cells = <2>;
> > +        #size-cells = <2>;
> > +
> > +        disp_ovl0_exdma2: dma-controller@...50000 {
> > +            compatible = "mediatek,mt8196-exdma";
> > +            reg = <0 0x32850000 0 0x1000>;
> > +            clocks = <&ovlsys_config_clk 13>;
> > +            power-domains = <&hfrpsys 12>;
> > +            mediatek,larb = <&smi_larb0>;
> 
> larb is controlled by iommu, and exdma has already point to iommu.
> OVL also not point to larb, so it's not necessary to point to larb
> here.
> 
> Regards,
> CK
> 
> 
> 
This is for the device-link.

Best, Paul
> 
> > +            iommus = <&mm_smmu 144>;
> > +            #dma-cells = <1>;
> > +        };
> > +    };
>