The StarFive VisionFive V1 SBC uses a Motorcomm YT8521 PHY supporting
RGMII-ID, but requires manual adjustment of the RX internal delay to
work properly.
The default RX delay provided by the driver is 1.95 ns, which proves to
be too high. Applying a 50% reduction seems to mitigate the issue.
Also note this adjustment is not necessary on BeagleV Starlight SBC,
which uses a Microchip PHY. Hence, there is no indication of a
miss-behaviour on the GMAC side, but most likely the issue stems from
the Motorcomm PHY.
Co-developed-by: Emil Renner Berthing <emil.renner.berthing@xxxxxxxxxxxxx>
Signed-off-by: Emil Renner Berthing <emil.renner.berthing@xxxxxxxxxxxxx>
Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@xxxxxxxxxxxxx>
---
.../boot/dts/starfive/jh7100-starfive-visionfive-v1.dts | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/arch/riscv/boot/dts/starfive/jh7100-starfive-visionfive-v1.dts b/arch/riscv/boot/dts/starfive/jh7100-starfive-visionfive-v1.dts
index e82af72f1aaf..ca134b9f11bf 100644
--- a/arch/riscv/boot/dts/starfive/jh7100-starfive-visionfive-v1.dts
+++ b/arch/riscv/boot/dts/starfive/jh7100-starfive-visionfive-v1.dts
@@ -18,3 +18,10 @@ gpio-restart {
priority = <224>;
};
};
+
+&mdio {
+ phy: ethernet-phy@0 {
+ reg = <0>;
+ rx-internal-delay-ps = <900>;
+ };
+};
--
2.43.0
