[PATCH AUTOSEL 5.4 162/266] ARM: dts: meson: Switch existing boards with RGMII PHY to "rgmii-id"

From: Martin Blumenstingl martin.blumenstingl@googlemail.com

[ Upstream commit 005231128e9e97461e81fa32421957a7664317ca ]

Let the PHY generate the RX and TX delay on the Odroid-C1 and MXIII Plus.

Previously we did not know that these boards used an RX delay. We assumed that setting the TX delay on the MAC side It turns out that these boards also require an RX delay of 2ns (verified on Odroid-C1, but the u-boot code uses the same setup on both boards). Ethernet only worked because u-boot added this RX delay on the MAC side.

The 4ns TX delay was also wrong and the result of using an unsupported RGMII TX clock divider setting. This has been fixed in the driver with commit bd6f48546b9cb7 ("net: stmmac: dwmac-meson8b: Fix the RGMII TX delay on Meson8b/8m2 SoCs").

Switch to phy-mode "rgmii-id" to let the PHY side handle all the delays, (as recommended by the Ethernet maintainers anyways) to correctly describe the need for a 2ns RX as well as 2ns TX delay on these boards. This fixes the Ethernet performance on Odroid-C1 where there was a huge amount of packet loss when transmitting data due to the incorrect TX delay.

Signed-off-by: Martin Blumenstingl martin.blumenstingl@googlemail.com Signed-off-by: Kevin Hilman khilman@baylibre.com Link: https://lore.kernel.org/r/20200512215148.540322-3-martin.blumenstingl@google... Signed-off-by: Sasha Levin sashal@kernel.org --- arch/arm/boot/dts/meson8b-odroidc1.dts | 3 +-- arch/arm/boot/dts/meson8m2-mxiii-plus.dts | 4 +--- 2 files changed, 2 insertions(+), 5 deletions(-)

diff --git a/arch/arm/boot/dts/meson8b-odroidc1.dts b/arch/arm/boot/dts/meson8b-odroidc1.dts index a24eccc354b9..10f6d601eadb 100644 --- a/arch/arm/boot/dts/meson8b-odroidc1.dts +++ b/arch/arm/boot/dts/meson8b-odroidc1.dts @@ -202,9 +202,8 @@ &ethmac { pinctrl-0 = <&eth_rgmii_pins>; pinctrl-names = "default";

- phy-mode = "rgmii"; phy-handle = <&eth_phy>; - amlogic,tx-delay-ns = <4>; + phy-mode = "rgmii-id";

nvmem-cells = <&ethernet_mac_address>; nvmem-cell-names = "mac-address"; diff --git a/arch/arm/boot/dts/meson8m2-mxiii-plus.dts b/arch/arm/boot/dts/meson8m2-mxiii-plus.dts index d54477b1001c..cc498191ddd1 100644 --- a/arch/arm/boot/dts/meson8m2-mxiii-plus.dts +++ b/arch/arm/boot/dts/meson8m2-mxiii-plus.dts @@ -69,9 +69,7 @@ &ethmac { pinctrl-names = "default";

phy-handle = <&eth_phy0>; - phy-mode = "rgmii"; - - amlogic,tx-delay-ns = <4>; + phy-mode = "rgmii-id";

mdio { compatible = "snps,dwmac-mdio";