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

From: Kevin Hilman <[email-masked]>
Date: Wed, 06 Feb 2019 19:04:58 -0800

Martin Blumenstingl <[email-masked]> writes:

> Hi Kevin,
>
> On Fri, Jan 11, 2019 at 2:09 AM Kevin Hilman <[email-masked]> wrote:
>>
>> Martin Blumenstingl <[email-masked]> 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 <[email-masked]>
>> > Cc: Emiliano Ingrassia <[email-masked]>
>> > Cc: Linus Lüssing <[email-masked]>
>>
>> Queued for v5.1 (branch: v5.1/dt)
> do you know what happened to this patch? I can't find it in v5.1/dt

Hmm, I'm not sure what happened to it, but I (re)added it to v5.1/dt
just now.

Kevin

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