| Message ID | 20231218214451.2345691-7-cristian.ciocaltea@collabora.com (mailing list archive) |
|---|---|
| State | Not Applicable, archived |
| Headers | show |
| Series | Enable networking support for StarFive JH7100 SoC | expand |
On Mon, Dec 18, 2023 at 11:44:46PM +0200, Cristian Ciocaltea wrote: > 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 > misbehaviour on the GMAC side, but most likely the issue stems from > the Motorcomm PHY. > > While at it, drop the redundant gpio include, which is already provided > by jh7100-common.dtsi. > > Co-developed-by: Emil Renner Berthing <emil.renner.berthing@canonical.com> > Signed-off-by: Emil Renner Berthing <emil.renner.berthing@canonical.com> > Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@collabora.com> Reviewed-by: Andrew Lunn <andrew@lunn.ch> Andrew
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..4e396f820660 100644 --- a/arch/riscv/boot/dts/starfive/jh7100-starfive-visionfive-v1.dts +++ b/arch/riscv/boot/dts/starfive/jh7100-starfive-visionfive-v1.dts @@ -6,7 +6,6 @@ /dts-v1/; #include "jh7100-common.dtsi" -#include <dt-bindings/gpio/gpio.h> / { model = "StarFive VisionFive V1"; @@ -18,3 +17,24 @@ gpio-restart { priority = <224>; }; }; + +/* + * The board 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 (1.95ns) is too high, but applying a 50% + * reduction seems to mitigate the issue. + * + * It is worth noting the adjustment is not necessary on BeagleV Starlight SBC, + * which uses a Microchip PHY. Hence, most likely the Motorcomm PHY is the one + * responsible for the misbehaviour, not the GMAC. + */ +&mdio { + phy: ethernet-phy@0 { + reg = <0>; + rx-internal-delay-ps = <900>; + }; +}; + +&gmac { + phy-handle = <&phy>; +};