linux-kernel - Re: [PATCH v8 1/4] dt-bindings: dmaengine: Add MediaTek Command-Queue DMA controller bindings

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Date:   Wed, 6 Jan 2021 17:25:40 +0800
From:   EastL <EastL.Lee@...iatek.com>
To:     Rob Herring <robh@...nel.org>
CC:     Sean Wang <sean.wang@...iatek.com>, <vkoul@...nel.org>,
        <mark.rutland@....com>, <matthias.bgg@...il.com>,
        <dmaengine@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-mediatek@...ts.infradead.org>, <devicetree@...r.kernel.org>,
        <wsd_upstream@...iatek.com>, <cc.hwang@...iatek.com>
Subject: Re: [PATCH v8 1/4] dt-bindings: dmaengine: Add MediaTek
 Command-Queue DMA controller bindings

On Sun, 2021-01-03 at 09:58 -0700, Rob Herring wrote:
> On Wed, Dec 23, 2020 at 05:30:44PM +0800, EastL Lee wrote:
> > Document the devicetree bindings for MediaTek Command-Queue DMA controller
> > which could be found on MT6779 SoC or other similar Mediatek SoCs.
> > 
> > Signed-off-by: EastL Lee <EastL.Lee@...iatek.com>
> > ---
> >  .../devicetree/bindings/dma/mtk-cqdma.yaml         | 104 +++++++++++++++++++++
> 
> Use compatible string for filename:
OK
> 
> mediatek,cqdma.yaml
> 
> >  1 file changed, 104 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/dma/mtk-cqdma.yaml
> > 
> > diff --git a/Documentation/devicetree/bindings/dma/mtk-cqdma.yaml b/Documentation/devicetree/bindings/dma/mtk-cqdma.yaml
> > new file mode 100644
> > index 0000000..a76a263
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/dma/mtk-cqdma.yaml
> > @@ -0,0 +1,104 @@
> > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/dma/mtk-cqdma.yaml#
> 
> Don't forget to update this.
OK
> 
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: MediaTek Command-Queue DMA controller Device Tree Binding
> > +
> > +maintainers:
> > +  - EastL Lee <EastL.Lee@...iatek.com>
> > +
> > +description:
> > +  MediaTek Command-Queue DMA controller (CQDMA) on Mediatek SoC
> > +  is dedicated to memory-to-memory transfer through queue based
> > +  descriptor management.
> > +
> > +allOf:
> > +  - $ref: "dma-controller.yaml#"
> > +
> > +properties:
> > +  compatible:
> > +    items:
> > +      - enum:
> > +          - mediatek,mt6765-cqdma
> > +          - mediatek,mt6779-cqdma
> > +      - const: mediatek,cqdma
> > +
> > +  reg:
> > +    minItems: 1
> > +    maxItems: 5
> > +    description:
> > +        A base address of MediaTek Command-Queue DMA controller,
> > +        a channel will have a set of base address.
> > +
> > +  interrupts:
> > +    minItems: 1
> > +    maxItems: 5
> > +    description:
> > +        A interrupt number of MediaTek Command-Queue DMA controller,
> > +        one interrupt number per dma-channels.
> > +
> > +  clocks:
> > +    maxItems: 1
> > +
> > +  clock-names:
> > +    const: cqdma
> > +
> > +  dma-channel-mask:
> > +    description:
> > +       For DMA capability, We will know the addressing capability of
> > +       MediaTek Command-Queue DMA controller through dma-channel-mask.
> > +      minimum: 1
> > +      maximum: 63
> 
> Indentation is wrong here so this has no effect.
I'll fix it
> 
> A mask of 63 is 6 channels...
In my opinion, kernel dma mask if for 32/64 bit capability...
If I don't set dma mask I will get fail on DMATEST.
> 
> > +
> > +  dma-channels:
> > +    description:
> > +      Number of DMA channels supported by MediaTek Command-Queue DMA
> > +      controller, support up to five.
> > +      minimum: 1
> > +      maximum: 5
> 
> Same here.
OK
> 
> Do you really need both dma-channels and dma-channel-mask? You should be 
> able to get one from the other.
> 
> > +
> > +  dma-requests:
> > +    description:
> > +      Number of DMA request (virtual channel) supported by MediaTek
> > +      Command-Queue DMA controller, support up to 32.
> > +      minimum: 1
> > +      maximum: 32
> 
> And here.
> 
> You are missing '#dma-cells' also.
OK I'll fix it.
> 
> > +
> > +required:
> > +  - "#dma-cells"
> > +  - compatible
> > +  - reg
> > +  - interrupts
> > +  - clocks
> > +  - clock-names
> > +  - dma-channel-mask
> > +  - dma-channels
> > +  - dma-requests
> > +
> > +additionalProperties: false
> > +
> > +examples:
> > +  - |
> > +    #include <dt-bindings/interrupt-controller/irq.h>
> > +    #include <dt-bindings/interrupt-controller/arm-gic.h>
> > +    #include <dt-bindings/clock/mt6779-clk.h>
> > +    cqdma: dma-controller@...12000 {
> > +        compatible = "mediatek,mt6779-cqdma";
> 
> This should fail validation because it doesn't match the schema. You ran 
> 'make dt_binding_check', right?
Yes, but I got other fail on kernel-5.10...
> 
> > +        reg = <0x10212000 0x80>,
> > +            <0x10212080 0x80>,
> > +            <0x10212100 0x80>;
> > +        interrupts = <GIC_SPI 139 IRQ_TYPE_LEVEL_LOW>,
> > +            <GIC_SPI 140 IRQ_TYPE_LEVEL_LOW>,
> > +            <GIC_SPI 141 IRQ_TYPE_LEVEL_LOW>;
> > +        clocks = <&infracfg_ao CLK_INFRA_CQ_DMA>;
> > +        clock-names = "cqdma";
> > +        dma-channel-mask = <63>;
> 
> 6 channels or...
> 
> > +        dma-channels = <3>;
> 
> 3?
3 channel, the mask is for DMATEST PASS.
> 
> > +        dma-requests = <32>;
> > +        #dma-cells = <1>;
> > +    };
> > +
> > +...
> > -- 
> > 1.9.1
> >