Re: [PATCH 3/5] dt-bindings: net: Add Loongson-1 DWMAC glue layer

[Keguang Zhang]

On Fri, Aug 18, 2023 at 9:48 PM Serge Semin <fancer.lancer@xxxxxxxxx> wrote:
>
> On Fri, Aug 18, 2023 at 06:42:42PM +0800, Keguang Zhang wrote:
> > On Wed, Aug 16, 2023 at 8:54 PM Serge Semin <fancer.lancer@xxxxxxxxx> wrote:
> > >
> > > Hi Keguang
> > >
> > > On Sat, Aug 12, 2023 at 11:11:33PM +0800, Keguang Zhang wrote:
> > > > Add devicetree binding document for Loongson-1 DWMAC glue layer.
> > > >
> > > > Signed-off-by: Keguang Zhang <keguang.zhang@xxxxxxxxx>
> > > > ---
> > > >  .../bindings/net/loongson,ls1x-dwmac.yaml     | 98 +++++++++++++++++++
> > > >  .../devicetree/bindings/net/snps,dwmac.yaml   |  2 +
> > > >  2 files changed, 100 insertions(+)
> > > >  create mode 100644 Documentation/devicetree/bindings/net/loongson,ls1x-dwmac.yaml
> > > >
> > > > diff --git a/Documentation/devicetree/bindings/net/loongson,ls1x-dwmac.yaml b/Documentation/devicetree/bindings/net/loongson,ls1x-dwmac.yaml
> > > > new file mode 100644
> > > > index 000000000000..150799460599
> > > > --- /dev/null
> > > > +++ b/Documentation/devicetree/bindings/net/loongson,ls1x-dwmac.yaml
> > > > @@ -0,0 +1,98 @@
> > > > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > > > +%YAML 1.2
> > > > +---
> > > > +$id: http://devicetree.org/schemas/net/loongson,ls1x-dwmac.yaml#
> > > > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > > > +
> > >
> > > > +title: Loongson-1 DWMAC glue layer
> > >
> > > DT-schemas describe a device. It has nothing to do with the glue
> > > driver/layer/whatever.
> > >
>
> > OK. But what about the MODULE_DESCRIPTION in dwmac-loongson1.c
> > MODULE_DESCRIPTION("Loongson1 DWMAC glue layer");
> > Should the two parts be aligned with each other?
>
> No they shouldn't. MODULE_DESCRIPTION() describes the driver module.
> "Loongson1 (G)MAC glue layer" is a correct description of the kernel
> driver module.
>
> > If not, what's your suggestion then?
>
> Something like "Loongson-1 Ethernet controller" or "Loongson-1 (G)MAC
> controller". A name which would refer to the device itself
> irrespective to the driver name, driver design, etc.
>
> * Note the already available DW (XG)MAC vendor-specific DT-bindings
> * referring to the glue layer/driver in the title property are wrong
> * in doing that.
>
> >
> > > Also I suggest to add a brief device description in the
> > > "description:" property and add there a brief info regarding the SoCs
> > > the controllers can be found on, the DW (G)MAC IP-core version the
> > > ethernet controllers are based on and if possible some data about the
> > > synthesize parameters: SMA (MDIO-bus), Tx/Rx COE, DMA FIFOs size,
> > > perfect and hash MAC-filters size, L3L4 frame filters availability,
> > > PHY interfaces (MII, RMII, RGMII, etc), EEE support, IEEE 1588(-2008)
> > > Timestamping support, PMT and Wake-up frame support, MAC Management
> > > counters (MMC).
> > >
> > > Note DMA FIFO sizes can be also constrained in the properties
> > > "rx-fifo-depth" and "tx-fifo-depth"; perfect and hash MAC-filter sizes -
> > > in "snps,perfect-filter-entries" and "snps,multicast-filter-bins".
> > >
> > OK. The description could be added in next version.
> >
> > > > +
> > > > +maintainers:
> > > > +  - Keguang Zhang <keguang.zhang@xxxxxxxxx>
> > > > +
> > > > +select:
> > > > +  properties:
> > > > +    compatible:
> > > > +      contains:
> > > > +        enum:
> > > > +          - loongson,ls1b-dwmac
> > > > +          - loongson,ls1c-dwmac
> > > > +  required:
> > > > +    - compatible
> > > > +
> > > > +properties:
> > > > +  compatible:
> > > > +    items:
> > > > +      - enum:
>
> > > > +          - loongson,ls1b-dwmac
> > > > +          - loongson,ls1c-dwmac
>
> BTW referring to the DW IP-core in the compatible string isn't very
> much useful especially seeing you have a generic fallback compatible.
>
> The next names would be more descriptive:
> loongson,ls1b-gmac - seeing MAC supports 10/100/1000 speed modes
> loongson,ls1c-mac - seeing MAC support 10/100 speed modes only
>
>
> > > > +      - const: snps,dwmac-3.50a
> > > > +
> > > > +  reg:
> > > > +    maxItems: 1
> > > > +
> > > > +  clocks:
> > > > +    maxItems: 1
> > > > +
> > > > +  clock-names:
> > > > +    const: stmmaceth
> > > > +
> > > > +  interrupts:
> > > > +    maxItems: 1
> > > > +
> > > > +  interrupt-names:
> > > > +    const: macirq
> > > > +
> > >
> > > > +  syscon:
> > > > +    $ref: /schemas/types.yaml#/definitions/phandle
> > > > +    description:
> > > > +      Phandle to the syscon containing some extra configurations
> > > > +      including PHY interface mode.
> > >
> > > I believe the property is supposed to have a vendor-specific name like
> > > "loongson,ls1-syscon" or similar.
> >
>
> > This has been fixed in v2.
>
> The name "loongson,dwmac-syscon" doesn't look correct because "dwmac-"
> prefix refer to some DWMAC system controller meanwhile the phandle
> passed to the device is a generic Loongson1 SoC system controller. So
> "loongson,ls1-syscon" looks more suitable.
>
Will do.

> > Could you please review v2?
> > Thanks!
>
> I'll have a look at v3 since v2 doesn't have my comments taken into
> account. BTW don't rush with resubmitting your series. Give it at
> least one week or so to hang out in the reviewers mail boxes as the
> Linux kernel patches review process suggests.
>
> > >
> > > > +
> > > > +required:
> > > > +  - compatible
> > > > +  - reg
> > > > +  - clocks
> > > > +  - clock-names
> > > > +  - interrupts
> > > > +  - interrupt-names
> > > > +  - phy-handle
> > >
> > > > +  - phy-mode
> > >
> > > You may want to specify the enum-constraints with the value permitted
> > > for the particular Loongson (G)MAC controller. Seeing ls1b and ls1c
> > > imply different sets of the PHY-modes the constraints are better to be
> > > defined in the allOf sub-schemas. Alternatively you can split the
> > > DT-schema file into two: one for ls1b-dwmac, another one for
> > > ls1c-dwmac. IMO the later option seems better.
> > >
>
> > The "phy-mode", as pointed by Krzysztof, is defined in
> > ethernet-controller and already required by snps,dwmac.
> > So I have dropped it in v2.
>
> My point was in specifying a particular constraints on the "phy-mode"
> property. Krzysztof correctly suggested to drop the property from the
> "required" list since it's already required by the snps,dwmac.yaml
> schema. One doesn't contradict to another.
>
> > For allOf sub-schemas, do you mean something below?
> > allOf:
> >  - $ref: snps,dwmac.yaml#
> >
> >  - if:
> >      properties:
> >        compatible:
> >          contains:
> >            const: loongson,ls1b-dwmac
> >    then:
> >      properties:
> >        phy-mode:
> >          enum:
> >            - mii
> >            - rgmii
> >
> >  - if:
> >      properties:
> >        compatible:
> >          contains:
> >            const: loongson,ls1c-dwmac
> >    then:
> >      properties:
> >        phy-mode:
> >          enum:
> >            - mii
> >            - rmii
>
> Yes. But IMO in order to prevent having such complicated multi-level
> schemas you can just split up your bindings into two:
> loongson,ls1b-dwmac.yaml
> and
> loongson,ls1c-dwmac.yaml
>
> Thus you'll be able to have a device-specific generic "title" and
> "description" in each of them (especially seeing LS1-C MAC lacks of
> 1000Mbps mode support which you said you would add to the bindings
> description), simpler "compatible" and "phy-mode" property
> constraints.
>
OK. I will split this file into loongson,ls1b-gmac.yaml and
loongson,ls1c-mac.yaml.
Thanks for your review!



> -Serge(y)
>
> >
> > > -Serge(y)
> > >
> > > > +  - syscon
> > > > +
> > > > +allOf:
> > > > +  - $ref: snps,dwmac.yaml#
> > > > +
> > > > +unevaluatedProperties: false
> > > > +
> > > > +examples:
> > > > +  - |
> > > > +    #include <dt-bindings/clock/loongson,ls1x-clk.h>
> > > > +    #include <dt-bindings/interrupt-controller/irq.h>
> > > > +
> > > > +    gmac0: ethernet@1fe10000 {
> > > > +        compatible = "loongson,ls1b-dwmac", "snps,dwmac-3.50a";
> > > > +        reg = <0x1fe10000 0x10000>;
> > > > +
> > > > +        clocks = <&clkc LS1X_CLKID_AHB>;
> > > > +        clock-names = "stmmaceth";
> > > > +
> > > > +        interrupt-parent = <&intc1>;
> > > > +        interrupts = <2 IRQ_TYPE_LEVEL_HIGH>;
> > > > +        interrupt-names = "macirq";
> > > > +
> > > > +        phy-handle = <&phy0>;
> > > > +        phy-mode = "mii";
> > > > +
> > > > +        snps,pbl = <1>;
> > > > +        syscon = <&syscon>;
> > > > +
> > > > +        mdio {
> > > > +            #address-cells = <1>;
> > > > +            #size-cells = <0>;
> > > > +            compatible = "snps,dwmac-mdio";
> > > > +
> > > > +            phy0: ethernet-phy@0 {
> > > > +                reg = <0x0>;
> > > > +            };
> > > > +        };
> > > > +    };
> > > > diff --git a/Documentation/devicetree/bindings/net/snps,dwmac.yaml b/Documentation/devicetree/bindings/net/snps,dwmac.yaml
> > > > index ddf9522a5dc2..e1a956cf171e 100644
> > > > --- a/Documentation/devicetree/bindings/net/snps,dwmac.yaml
> > > > +++ b/Documentation/devicetree/bindings/net/snps,dwmac.yaml
> > > > @@ -66,6 +66,8 @@ properties:
> > > >          - ingenic,x2000-mac
> > > >          - loongson,ls2k-dwmac
> > > >          - loongson,ls7a-dwmac
> > > > +        - loongson,ls1b-dwmac
> > > > +        - loongson,ls1c-dwmac
> > > >          - qcom,qcs404-ethqos
> > > >          - qcom,sa8775p-ethqos
> > > >          - qcom,sc8280xp-ethqos
> > > > --
> > > > 2.39.2
> > > >
> >
> >
> >
> > --
> > Best regards,
> >
> > Keguang Zhang



--
Best regards,

Keguang Zhang