Re: [PATCH] riscv: dts: sophgo: add cv1800b ethernet support overlay

[Hiago De Franco <hfranco@baylibre.com>]

Hi Inochi Amaoto,

Just a friendly ping about this patch. Not sure if it was picked up by
you already.

Thanks!

On Thu, Oct 01, 2026 at 04:38:30PM -0300, Hiago De Franco wrote:
> The CV1800B SoC has a DWMAC controller connected to an internal 10/100
> Ethernet PHY. Both the MAC (gmac0) and the MDIO multiplexer used to
> reach the internal PHY are already described in cv180x.dtsi, but are
> disabled by default.
> 
> Enable gmac0 and the MDIO multiplexer to make ethernet work.
> 
> Tested on a Milk-V Duo (CV1800B) with its IO base board. The link comes
> up at 100Mbps/Full and the interface gets an address via DHCP.
> 
> This can not be enabled by default as others may want to use the same
> pins as GPIO, that is the reason an overlay is being used.
> 
> Signed-off-by: Hiago De Franco <hfranco@baylibre.com>
> ---
> Hi,
> 
> This is a continuation of patch [1]. The same patch was sent before [2],
> and an overlay was suggested, altought it was not sent. Therefore I am
> sending this overlay now.
> 
> U-Boot logs:
> 
> milkv_duo# setenv fdtoverlay_addr_r 0x82480000
> milkv_duo# boot
> ** Booting bootflow 'mmc@4310000.bootdev.part_1' with extlinux
> 1:	Poky (Yocto Project Reference Distro)
> Retrieving file: /Image.gz
> append: root=/dev/mmcblk0p2 ro rootwait console=ttyS0,115200 earlycon=sbi
> Retrieving file: /cv1800b-milkv-duo.dtb
> Retrieving file: /cv1800b-milkv-duo-eth.dtbo
>    Uncompressing Kernel Image to 0
> \## Flattened Device Tree blob at 82200000
>    Booting using the fdt blob at 0x82200000
> Working FDT set to 82200000
>    Loading Device Tree to 0000000083560000, end 0000000083568fff ... OK
> Working FDT set to 83560000
> 
> Kernel logs:
> 
> root@milkv-duo:~# ip a
> 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue qlen 1000
>     link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
>     inet 127.0.0.1/8 scope host lo
>        valid_lft forever preferred_lft forever
> 2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq qlen 1000
>     link/ether 22:9c:5e:8d:3b:0c brd ff:ff:ff:ff:ff:ff
>     inet 192.168.0.124/24 brd 192.168.0.255 scope global eth0
>        valid_lft forever preferred_lft forever
> root@milkv-duo:~# dmesg | grep stmmaceth
> [    0.580448] stmmaceth 4070000.ethernet: IRQ eth_wake_irq not found
> [    0.587750] stmmaceth 4070000.ethernet: IRQ sfty not found
> [    0.594165] stmmaceth 4070000.ethernet: Hash table entries set to unexpected value 0
> [    0.604856] stmmaceth 4070000.ethernet: User ID: 0x10, Synopsys ID: 0x37
> [    0.612359] stmmaceth 4070000.ethernet: 	DWMAC1000
> [    0.617641] stmmaceth 4070000.ethernet: DMA HW capability register supported
> [    0.625189] stmmaceth 4070000.ethernet: Active PHY interface: RMII (4)
> [    0.632191] stmmaceth 4070000.ethernet: RX Checksum Offload Engine supported
> [    0.639720] stmmaceth 4070000.ethernet: COE Type 2
> [    0.644915] stmmaceth 4070000.ethernet: TX Checksum insertion supported
> [    0.651995] stmmaceth 4070000.ethernet: Normal descriptors
> [    0.657911] stmmaceth 4070000.ethernet: Ring mode enabled
> [    0.663737] stmmaceth 4070000.ethernet: Enable RX Mitigation via HW Watchdog Timer
> [    0.671939] stmmaceth 4070000.ethernet: device MAC address 22:9c:5e:8d:3b:0c
> [   13.104870] stmmaceth 4070000.ethernet eth0: Register MEM_TYPE_PAGE_POOL RxQ-0
> [   13.125037] stmmaceth 4070000.ethernet eth0: PHY [mdio_mux-0.0:01] driver [Generic PHY] (irq=POLL)
> [   13.172421] stmmaceth 4070000.ethernet eth0: No Safety Features support found
> [   13.203664] stmmaceth 4070000.ethernet eth0: IEEE 1588-2002 Timestamp supported
> [   13.229963] stmmaceth 4070000.ethernet eth0: configuring for phy/internal link mode
> [   15.278278] stmmaceth 4070000.ethernet eth0: Link is Up - 100Mbps/Full - flow control rx/tx
> 
> [1] https://lore.kernel.org/sophgo/20260930-milkv-duo-ethernet-v1-1-428ff137f5d3@baylibre.com/
> [2] https://lore.kernel.org/sophgo/20260803163323.74414-1-chenyou910331@gmail.com/
> ---
>  arch/riscv/boot/dts/sophgo/Makefile                   |  3 +++
>  arch/riscv/boot/dts/sophgo/cv1800b-milkv-duo-eth.dtso | 17 +++++++++++++++++
>  2 files changed, 20 insertions(+)
> 
> diff --git a/arch/riscv/boot/dts/sophgo/Makefile b/arch/riscv/boot/dts/sophgo/Makefile
> index d5c80d4ff005..adea990ad912 100644
> --- a/arch/riscv/boot/dts/sophgo/Makefile
> +++ b/arch/riscv/boot/dts/sophgo/Makefile
> @@ -1,5 +1,8 @@
>  # SPDX-License-Identifier: GPL-2.0
>  dtb-$(CONFIG_ARCH_SOPHGO) += cv1800b-milkv-duo.dtb
> +cv1800b-milkv-duo-eth-dtbs := cv1800b-milkv-duo.dtb cv1800b-milkv-duo-eth.dtbo
> +dtb-$(CONFIG_ARCH_SOPHGO) += cv1800b-milkv-duo-eth.dtb
> +dtb-$(CONFIG_ARCH_SOPHGO) += cv1800b-milkv-duo-eth.dtbo
>  dtb-$(CONFIG_ARCH_SOPHGO) += cv1812h-huashan-pi.dtb
>  dtb-$(CONFIG_ARCH_SOPHGO) += sg2000-milkv-duo-s.dtb
>  dtb-$(CONFIG_ARCH_SOPHGO) += sg2002-licheerv-nano-b.dtb
> diff --git a/arch/riscv/boot/dts/sophgo/cv1800b-milkv-duo-eth.dtso b/arch/riscv/boot/dts/sophgo/cv1800b-milkv-duo-eth.dtso
> new file mode 100644
> index 000000000000..52c85b4e0155
> --- /dev/null
> +++ b/arch/riscv/boot/dts/sophgo/cv1800b-milkv-duo-eth.dtso
> @@ -0,0 +1,17 @@
> +// SPDX-License-Identifier: (GPL-2.0 OR MIT)
> +/*
> + * Enable ethernet support on Milk-V Duo (CV1800B).
> + *
> + * Copyright (c) 2026, Hiago De Franco <hfranco@baylibre.com>
> + */
> +
> +/dts-v1/;
> +/plugin/;
> +
> +&gmac0 {
> +	status = "okay";
> +};
> +
> +&mdio {
> +	status = "okay";
> +};
> 
> ---
> base-commit: d24e8ac715de2e16a53c144005b1863660a5fbea
> change-id: 20261001-milkv-duo-eth-overlay-cf7738449a40
> 
> Best regards,
> --  
> Hiago
> 

Best regards,
-- 
Hiago