Re: [PATCH v3 net-next 2/8] dt-bindings: net: mediatek: add WED RX binding for MT7986 eth driver

[Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>]

On 03/11/2022 13:51, Lorenzo Bianconi wrote:
>>> diff --git a/Documentation/devicetree/bindings/arm/mediatek/mediatek,mt7986-wo-boot.yaml b/Documentation/devicetree/bindings/arm/mediatek/mediatek,mt7986-wo-boot.yaml
>>> new file mode 100644
>>> index 000000000000..6c3c514c48ef
>>> --- /dev/null
>>> +++ b/Documentation/devicetree/bindings/arm/mediatek/mediatek,mt7986-wo-boot.yaml
>>
>> arm is only for top-level stuff. Choose appropriate subsystem, soc as
>> last resort.
> 
> these chips are used only for networking so is net folder fine?

So this is some MMIO and no actual device? Then rather soc.

> 
>>
>>> @@ -0,0 +1,47 @@
>>> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
>>> +%YAML 1.2
>>> +---
>>> +$id: http://devicetree.org/schemas/arm/mediatek/mediatek,mt7986-wo-boot.yaml#
>>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>>> +
>>> +title:
>>> +  MediaTek Wireless Ethernet Dispatch WO boot controller interface for MT7986
>>> +
>>> +maintainers:
>>> +  - Lorenzo Bianconi <lorenzo@kernel.org>
>>> +  - Felix Fietkau <nbd@nbd.name>
>>> +
>>> +description:
>>> +  The mediatek wo-boot provides a configuration interface for WED WO
>>> +  boot controller on MT7986 soc.
>>
>> And what is "WED WO boot controller?
> 
> WED WO is a chip used for networking packet processing offloaded to the Soc
> (e.g. packet reordering). WED WO boot is the memory used to store start address
> of wo firmware. Anyway I will let Sujuan comment on this.

A bit more should be in description.

> 
>>
>>> +
>>> +properties:
>>> +  compatible:
>>> +    items:
>>> +      - enum:
>>> +          - mediatek,mt7986-wo-boot
>>> +      - const: syscon
>>> +
>>> +  reg:
>>> +    maxItems: 1
>>> +
>>> +  interrupts:
>>> +    maxItems: 1
>>> +
>>> +required:
>>> +  - compatible
>>> +  - reg
>>> +
>>> +additionalProperties: false
>>> +
>>> +examples:
>>> +  - |
>>> +    soc {
>>> +      #address-cells = <2>;
>>> +      #size-cells = <2>;
>>> +
>>> +      wo_boot: syscon@15194000 {
>>> +        compatible = "mediatek,mt7986-wo-boot", "syscon";
>>> +        reg = <0 0x15194000 0 0x1000>;
>>> +      };
>>> +    };
>>> diff --git a/Documentation/devicetree/bindings/arm/mediatek/mediatek,mt7986-wo-ccif.yaml b/Documentation/devicetree/bindings/arm/mediatek/mediatek,mt7986-wo-ccif.yaml
>>> new file mode 100644
>>> index 000000000000..6357a206587a
>>> --- /dev/null
>>> +++ b/Documentation/devicetree/bindings/arm/mediatek/mediatek,mt7986-wo-ccif.yaml
>>> @@ -0,0 +1,50 @@
>>> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
>>> +%YAML 1.2
>>> +---
>>> +$id: http://devicetree.org/schemas/arm/mediatek/mediatek,mt7986-wo-ccif.yaml#
>>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>>> +
>>> +title: MediaTek Wireless Ethernet Dispatch WO controller interface for MT7986
>>> +
>>> +maintainers:
>>> +  - Lorenzo Bianconi <lorenzo@kernel.org>
>>> +  - Felix Fietkau <nbd@nbd.name>
>>> +
>>> +description:
>>> +  The mediatek wo-ccif provides a configuration interface for WED WO
>>> +  controller on MT7986 soc.
>>
>> All previous comments apply.
>>
>>> +
>>> +properties:
>>> +  compatible:
>>> +    items:
>>> +      - enum:
>>> +          - mediatek,mt7986-wo-ccif
>>> +      - const: syscon
>>> +
>>> +  reg:
>>> +    maxItems: 1
>>> +
>>> +  interrupts:
>>> +    maxItems: 1
>>> +
>>> +required:
>>> +  - compatible
>>> +  - reg
>>> +  - interrupts
>>> +
>>> +additionalProperties: false
>>> +
>>> +examples:
>>> +  - |
>>> +    #include <dt-bindings/interrupt-controller/arm-gic.h>
>>> +    #include <dt-bindings/interrupt-controller/irq.h>
>>> +    soc {
>>> +      #address-cells = <2>;
>>> +      #size-cells = <2>;
>>> +
>>> +      wo_ccif0: syscon@151a5000 {
>>> +        compatible = "mediatek,mt7986-wo-ccif", "syscon";
>>> +        reg = <0 0x151a5000 0 0x1000>;
>>> +        interrupts = <GIC_SPI 205 IRQ_TYPE_LEVEL_HIGH>;
>>> +      };
>>> +    };
>>> diff --git a/Documentation/devicetree/bindings/arm/mediatek/mediatek,mt7986-wo-dlm.yaml b/Documentation/devicetree/bindings/arm/mediatek/mediatek,mt7986-wo-dlm.yaml
>>> new file mode 100644
>>> index 000000000000..a499956d9e07
>>> --- /dev/null
>>> +++ b/Documentation/devicetree/bindings/arm/mediatek/mediatek,mt7986-wo-dlm.yaml
>>> @@ -0,0 +1,50 @@
>>> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
>>> +%YAML 1.2
>>> +---
>>> +$id: http://devicetree.org/schemas/arm/mediatek/mediatek,mt7986-wo-dlm.yaml#
>>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>>> +
>>> +title: MediaTek Wireless Ethernet Dispatch WO hw rx ring interface for MT7986
>>> +
>>> +maintainers:
>>> +  - Lorenzo Bianconi <lorenzo@kernel.org>
>>> +  - Felix Fietkau <nbd@nbd.name>
>>> +
>>> +description:
>>> +  The mediatek wo-dlm provides a configuration interface for WED WO
>>> +  rx ring on MT7986 soc.
>>> +
>>> +properties:
>>> +  compatible:
>>> +    const: mediatek,mt7986-wo-dlm
>>> +
>>> +  reg:
>>> +    maxItems: 1
>>> +
>>> +  resets:
>>> +    maxItems: 1
>>> +
>>> +  reset-names:
>>> +    maxItems: 1
>>> +
>>> +required:
>>> +  - compatible
>>> +  - reg
>>> +  - resets
>>> +  - reset-names
>>> +
>>> +additionalProperties: false
>>> +
>>> +examples:
>>> +  - |
>>> +    soc {
>>> +      #address-cells = <2>;
>>> +      #size-cells = <2>;
>>> +
>>> +      wo_dlm0: wo-dlm@151e8000 {
>>
>> Node names should be generic.
>> https://devicetree-specification.readthedocs.io/en/latest/chapter2-devicetree-basics.html#generic-names-recommendation
> 
> DLM is a chip used to store the data rx ring of wo firmware. I do not have a
> better node name (naming is always hard). Can you please suggest a better name?

The problem is that you added three new devices which seem to be for the
same device - WED. It looks like some hacky way of avoid proper hardware
description - let's model everything as MMIO and syscons...

For such model - register addresses exposed as separate devices - I do
not have appropriate name, but the real problem is not in the name. It's
in the hardware description.


Best regards,
Krzysztof