Re: [PATCH v3 2/2] ARM: dts: meson8b: fix the Ethernet data line signals in eth_rgmii_pins

[Emiliano Ingrassia <ingrassia@epigenesys.com>]

On Thu, Jan 10, 2019 at 05:09:47PM -0800, Kevin Hilman wrote:
> Martin Blumenstingl <martin.blumenstingl@googlemail.com> writes:
>
> > According to the Odroid-C1+ schematics the Ethernet TXD1 signal is
> > routed to GPIOH_5 and the TXD0 signal is routed to GPIOH_6.
> > The public S805 datasheet shows that TXD0 can be routed to DIF_2_P and
> > TXD1 can be routed to DIF_2_N instead.
> >
> > The pin groups eth_txd0_0 (GPIOH_6) and eth_txd0_1 (DIF_2_P) are both
> > configured as Ethernet TXD0 and TXD1 data lines in meson8b.dtsi. At the
> > same time eth_txd1_0 (GPIOH_5) and eth_txd1_1 (DIF_2_N) are configured
> > as TXD0 and TXD1 data lines as well.
> > This results in a bad Ethernet receive performance. Presumably this is
> > due to the eth_txd0 and eth_txd1 signal being routed to the wrong pins.
> > As a result of that data can only be transmitted on eth_txd2 and
> > eth_txd3. However, I have no scope to fully confirm this assumption.
> >
> > The vendor u-boot sources for Odroid-C1 use the following Ethernet
> > pinmux configuration:
> >   SET_CBUS_REG_MASK(PERIPHS_PIN_MUX_6, 0x3f4f);
> >   SET_CBUS_REG_MASK(PERIPHS_PIN_MUX_7, 0xf00000);
> > This translates to the following pin groups in the mainline kernel:
> > - register 6 bit  0: eth_rxd1 (DIF_0_P)
> > - register 6 bit  1: eth_rxd0 (DIF_0_N)
> > - register 6 bit  2: eth_rx_dv (DIF_1_P)
> > - register 6 bit  3: eth_rx_clk (DIF_1_N)
> > - register 6 bit  6: eth_tx_en (DIF_3_P)
> > - register 6 bit  8: eth_ref_clk (DIF_3_N)
> > - register 6 bit  9: eth_mdc (DIF_4_P)
> > - register 6 bit 10: eth_mdio_en (DIF_4_N)
> > - register 6 bit 11: eth_tx_clk (GPIOH_9)
> > - register 6 bit 12: eth_txd2 (GPIOH_8)
> > - register 6 bit 13: eth_txd3 (GPIOH_7)
> > - register 7 bit 20: eth_txd0_0 (GPIOH_6)
> > - register 7 bit 21: eth_txd1_0 (GPIOH_5)
> > - register 7 bit 22: eth_rxd3 (DIF_2_P)
> > - register 7 bit 23: eth_rxd2 (DIF_2_N)
> >
> > Drop the eth_txd0_1 and eth_txd1_1 groups from eth_rgmii_pins to fix the
> > Ethernet transmit performance on Odroid-C1. Also add the eth_rxd2 and
> > eth_rxd3 groups so we don't rely on the bootloader to set them up.
> >
> > iperf3 statistics before this change:
> > - transmitting from Odroid-C1: 741 Mbits/sec (0 retries)
> > - receiving on Odroid-C1: 199 Mbits/sec (1713 retries)
> >
> > iperf3 statistics after this change:
> > - transmitting from Odroid-C1: 667 Mbits/sec (0 retries)
> > - receiving on Odroid-C1: 750 Mbits/sec (0 retries)
> >
> > Fixes: b96446541d8390 ("ARM: dts: meson8b: extend ethernet controller description")
> > Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
> > Cc: Emiliano Ingrassia <ingrassia@epigenesys.com>
> > Cc: Linus Lüssing <linus.luessing@c0d3.blue>
>
> Queued for v5.1 (branch: v5.1/dt)
>
> Kevin

Tested-by: Emiliano Ingrassia <ingrassia@epigenesys.com>
Reviewed-by: Emiliano Ingrassia <ingrassia@epigenesys.com>

Emiliano

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