Martin Blumenstingl
29f0023d01
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: b96446541d ("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>
Tested-by: Emiliano Ingrassia <ingrassia@epigenesys.com>
Reviewed-by: Emiliano Ingrassia <ingrassia@epigenesys.com>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.