Re: [PATCH net-next 08/16] dt-bindings: net: Add Synopsys DW xPCS bindings

Rob Herring
2023-12-14T17:41:23Z

On Tue, Dec 05, 2023 at 01:35:29PM +0300, Serge Semin wrote:
> Synopsys DesignWare XPCS IP-core is a Physical Coding Sublayer (PCS) layer
> providing an interface between the Media Access Control (MAC) and Physical
> Medium Attachment Sublayer (PMA) through a Media independent interface.
> >From software point of view it exposes IEEE std. Clause 45 CSR space and
> can be accessible either by MDIO or MCI/APB3 bus interfaces. The later
> case is described by means of a dedicated DT-bindings which imply having
> the DW XPCS Management Interface defined as a DT-supernode which child the
> PCSs nodes would be (in the same way as the standard MDIO buses and
> devices are normally defined).
>
> Besides of that DW XPCS DT-nodes can have the interrupts and clock source
> properties specified. The former one indicates the Clause 73/37
> auto-negotiation events like: negotiation page received, AN is completed
> or incompatible link partner. The clock DT-properties can describe up to
> two clock sources: internal one and the one connected to the chip pad.
> Either of them is supposed to be used as the device reference clocks.
>
> Finally the DW XPCS IP-core can be optionally synthesized with a
> vendor-specific interface connected to Synopsys PMA (also called
> DesignWare Consumer/Enterprise PHY). Alas that isn't auto-detectable
> anyhow so if the DW XPCS device has the respective PMA attached then it
> should be reflected in the DT-node compatible string so the driver would
> be aware of the PMA-specific device capabilities (mainly connected with
> CSRs available for the fine-tunings).
>
> Signed-off-by: Serge Semin <fancer.lancer@gmail.com>
> ---
> .../bindings/net/pcs/snps,dw-xpcs.yaml | 88 +++++++++++++++++++
> .../bindings/net/snps,dw-xpcs-mi.yaml | 88 +++++++++++++++++++
> 2 files changed, 176 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/net/pcs/snps,dw-xpcs.yaml
> create mode 100644 Documentation/devicetree/bindings/net/snps,dw-xpcs-mi.yaml
>
> diff --git a/Documentation/devicetree/bindings/net/pcs/snps,dw-xpcs.yaml b/Documentation/devicetree/bindings/net/pcs/snps,dw-xpcs.yaml
> new file mode 100644
> index 000000000000..9694ef51abad
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/net/pcs/snps,dw-xpcs.yaml
> @@ -0,0 +1,88 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/net/pcs/snps,dw-xpcs.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Synopsys DesignWare Ethernet PCS
> +
> +maintainers:
> + - Jose Abreu <Jose.Abreu@synopsys.com>
> +
> +description:
> + Synopsys DesignWare Ethernet Physical Coding Sublayer provides an interface
> + between Media Access Control and Physical Medium Attachment Sublayer through
> + the Media Independent Interface (XGMII, USXGMII, XLGMII, GMII, etc)
> + controlled by means of the IEEE std. Clause 45 registers set. The PCS can be
> + optionally synthesized with a vendor-specific interface connected to
> + Synopsys PMA (also called DesignWare Consumer/Enterprise PHY) although in
> + general it can be used to communicate with any compatible PHY.
> +
> +properties:
> + compatible:
> + oneOf:
> + - description: Synopsys DesignWare XPCS with none or unknown PMA
> + const: snps,dw-xpcs
> + - description: Synopsys DesignWare XPCS with Consumer Gen1 3G PMA
> + const: snps,dw-xpcs-gen1-3g
> + - description: Synopsys DesignWare XPCS with Consumer Gen2 3G PMA
> + const: snps,dw-xpcs-gen2-3g
> + - description: Synopsys DesignWare XPCS with Consumer Gen2 6G PMA
> + const: snps,dw-xpcs-gen2-6g
> + - description: Synopsys DesignWare XPCS with Consumer Gen4 3G PMA
> + const: snps,dw-xpcs-gen4-3g
> + - description: Synopsys DesignWare XPCS with Consumer Gen4 6G PMA
> + const: snps,dw-xpcs-gen4-6g
> + - description: Synopsys DesignWare XPCS with Consumer Gen5 10G PMA
> + const: snps,dw-xpcs-gen5-10g
> + - description: Synopsys DesignWare XPCS with Consumer Gen5 12G PMA
> + const: snps,dw-xpcs-gen5-12g
> +
> + reg:
> + maxItems: 1
> +
> + interrupts:
> + description:
> + System interface interrupt output (sbd_intr_o) indicating Clause 73/37
> + auto-negotiation events like':' Page received, AN is completed or

like':' ?

> + incompatible link partner.
> + maxItems: 1
> +
> + clocks:
> + description:
> + PCS/PMA interface be can clocked either by internal reference clock
> + source or by an externally connected (via a pad) clock generator.
> + minItems: 1
> + maxItems: 2
> +
> + clock-names:
> + minItems: 1
> + maxItems: 2
> + items:
> + enum: [ core, pad ]
> +
> +required:
> + - compatible
> + - reg

Don't you always need a clock?

> +
> +additionalProperties: false
> +
> +examples:
> + - |
> + #include <dt-bindings/interrupt-controller/irq.h>
> +
> + mdio-bus {
> + #address-cells = <1>;
> + #size-cells = <0>;
> +
> + xgmac_pcs: ethernet-pcs@0 {
> + compatible = "snps,dw-xpcs";
> + reg = <0>;
> +
> + interrupts = <79 IRQ_TYPE_LEVEL_HIGH>;
> +
> + clocks = <&ccu_core>, <&ccu_pad>;
> + clock-names = "core", "pad";
> + };
> + };
> +...
> diff --git a/Documentation/devicetree/bindings/net/snps,dw-xpcs-mi.yaml b/Documentation/devicetree/bindings/net/snps,dw-xpcs-mi.yaml
> new file mode 100644
> index 000000000000..67ddba9d61fd
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/net/snps,dw-xpcs-mi.yaml
> @@ -0,0 +1,88 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/net/snps,dw-xpcs-mi.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Synopsys DesignWare Ethernet PCS Management Interface
> +
> +maintainers:
> + - Serge Semin <fancer.lancer@gmail.com>
> +
> +description:
> + Synopsys DesignWare Ethernet PCS provides an interface between MAC and PMA
> + through the Media Independent Interface. The PCS CSRs can be accessible over
> + the Ethernet MDIO bus or directly by means of the APB3/MCI interfaces. In the
> + later case the XPCS can be mapped right to the system IO memory space.
> +
> +allOf:
> + - $ref: mdio.yaml#
> +
> +properties:
> + compatible:
> + const: snps,dw-xpcs-mi
> +
> + reg:
> + items:
> + - description:
> + DW XPCS CSRs space can be either 'directly' or 'indirectly'
> + accessible. In the former case all Clause 45 registers are
> + contiguously mapped within the address space MMD '[20:16]',
> + Reg '[15:0]'. In the later case the space is divided to the
> + multiple 256 register sets. There is a special viewport CSR
> + which is responsible for the set selection. The upper part of
> + the CSR address is supposed to be written in there thus the
> + corresponding subset would be mapped over the lowest 255 CSRs.
> +
> + reg-names:
> + items:
> + - enum: [ direct, indirect ]
> +
> + reg-io-width:
> + description:
> + The way the CSRs are mapped to the memory is platform depended. Since

dependent

> + each Clause 45 CSR is of 16-bits wide the access instructions must be
> + two bytes aligned at least.
> + default: 2
> + enum: [ 2, 4 ]
> +
> + clocks:
> + items:
> + - description: Peripheral MCI/APB3 bus clock source
> +
> + clock-names:
> + items:
> + - const: pclk
> +
> +patternProperties:
> + 'ethernet-pcs@[0-9a-f]+$':
> + type: object
> +
> + $ref: pcs/snps,dw-xpcs.yaml#

This causes dw-xpcs to be validated twice. Does this MDIO bus support
other devices on it or it is fixed config?

> +
> +required:
> + - compatible
> + - reg
> + - reg-names
> +
> +unevaluatedProperties: false
> +
> +examples:
> + - |
> + mdio@1f05d000 {
> + compatible = "snps,dw-xpcs-mi";
> + reg = <0x1f05d000 0x1000>;
> + reg-names = "indirect";
> + #address-cells = <1>;
> + #size-cells = <0>;
> +
> + clocks = <&ccu_pclk>;
> + clock-names = "pclk";
> +
> + reg-io-width = <4>;
> +
> + ethernet-pcs@0 {
> + compatible = "snps,dw-xpcs";
> + reg = <0>;
> + };
> + };
> --
> 2.42.1
>