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

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

[Hiago De Franco]

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


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

[葉宸佑]

On Thu, Oct 01, 2026 at 04:38:30PM -0300, Hiago De Franco wrote:
> 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.

Thanks for picking this up. [2] was mine, for the Duo 256M; the overlay
rework stalled while I waited for the IO board, which has now arrived.
I will send the matching overlay for sg2002-milkv-duo256m in the same
shape as this one, so the two boards stay consistent.

One note, not a blocker for this patch: the internal PHY under the mdio
node this overlay enables is named phy@0 but has reg = <1> -- which is
also why it shows up as mdio_mux-0.0:01 in your log. 2/2 of my earlier
series [3] fixes the node name in cv180x.dtsi, so it covers CV1800B as
well, and already has Inochi's Reviewed-by. I will carry it in my
overlay series unless it lands first.

Reviewed-by: Chen-Yu Yeh <chenyou910331@gmail.com>

[3] https://lore.kernel.org/sophgo/20260803163427.74445-1-chenyou910331@gmail.com/

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

[Hiago De Franco]

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

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