On Fri, 2 Jan 2026, at 3:52 PM, Icenowy Zheng wrote:

Currently the LS7A GMAC device tree node lacks a proper phy-handle property pointing to the PHY node.

In addition, the phy-mode property specifies "rgmii" without any internal delay information, which means the board trace needs to add 2ns delay to the RGMII data lines; but that isn't known to happen on any Loongson board. The ACPI-based initialization codepath, which is used on LoongArch-based 3A5000 + 7A1000 hardwares, specifies "rgmii-id" phy mode, which should be the one we are using.

Add the lacking phy-handle property and set proper phy-mode.

Tested on a LS3A4000_7A1000_NUC_BOARD_V2.1 board with YT8521S PHY.

Signed-off-by: Icenowy Zheng zhengxingda@iscas.ac.cn

Good catch! This with fine with realtek phy chips but YT8521S seems to be picky.

Reviewed-by: Jiaxun Yang jiaxun.yang@flygoat.com

Also maybe:

Cc: stable@vger.kernel.org

Given those boards rely on built-in DT.

Thanks

---

arch/mips/boot/dts/loongson/ls7a-pch.dtsi | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/arch/mips/boot/dts/loongson/ls7a-pch.dtsi b/arch/mips/boot/dts/loongson/ls7a-pch.dtsi index ee71045883e7e..6dee85909f5a6 100644 --- a/arch/mips/boot/dts/loongson/ls7a-pch.dtsi +++ b/arch/mips/boot/dts/loongson/ls7a-pch.dtsi @@ -199,7 +199,8 @@ gmac@3,0 { <13 IRQ_TYPE_LEVEL_HIGH>; interrupt-names = "macirq", "eth_lpi"; interrupt-parent = <&pic>;

• 		phy-mode = "rgmii";
  

• 		phy-mode = "rgmii-id";
  

• 		phy-handle = <&phy0>;
  	mdio {
  		#address-cells = <1>;
  		#size-cells = <0>;
  

@@ -222,7 +223,8 @@ gmac@3,1 { <15 IRQ_TYPE_LEVEL_HIGH>; interrupt-names = "macirq", "eth_lpi"; interrupt-parent = <&pic>;

• 		phy-mode = "rgmii";
  

• 		phy-mode = "rgmii-id";
  

• 		phy-handle = <&phy1>;
  	mdio {
  		#address-cells = <1>;
  		#size-cells = <0>;
  

-- 2.52.0