Currently the dwmac-meson8b stmmac glue driver uses a hardcoded 1/4 cycle (= 2ns) TX clock delay. This seems to work fine for many boards (for example Odroid-C2 or Amlogic's reference boards) but there are some others where TX traffic is simply broken. There are probably multiple reasons why it's working on some boards while it's broken on others: - some of Amlogic's reference boards are using a Micrel PHY - hardware circuit design - maybe more... iperf3 results on my Mecool BB2 board (Meson GXM, RTL8211F PHY) with TX clock delay disabled on the MAC (as it's enabled in the PHY driver). TX throughput was virtually zero before: $ iperf3 -c 192.168.1.100 -R Connecting to host 192.168.1.100, port 5201 Reverse mode, remote host 192.168.1.100 is sending [ 4] local 192.168.1.206 port 52828 connected to 192.168.1.100 port 5201 [ ID] Interval Transfer Bandwidth [ 4] 0.00-1.00 sec 108 MBytes 901 Mbits/sec [ 4] 1.00-2.00 sec 94.2 MBytes 791 Mbits/sec [ 4] 2.00-3.00 sec 96.5 MBytes 810 Mbits/sec [ 4] 3.00-4.00 sec 96.2 MBytes 808 Mbits/sec [ 4] 4.00-5.00 sec 96.6 MBytes 810 Mbits/sec [ 4] 5.00-6.00 sec 96.5 MBytes 810 Mbits/sec [ 4] 6.00-7.00 sec 96.6 MBytes 810 Mbits/sec [ 4] 7.00-8.00 sec 96.5 MBytes 809 Mbits/sec [ 4] 8.00-9.00 sec 105 MBytes 884 Mbits/sec [ 4] 9.00-10.00 sec 111 MBytes 934 Mbits/sec - - - - - - - - - - - - - - - - - - - - - - - - - [ ID] Interval Transfer Bandwidth Retr [ 4] 0.00-10.00 sec 1000 MBytes 839 Mbits/sec 0 sender [ 4] 0.00-10.00 sec 998 MBytes 837 Mbits/sec receiver iperf Done. $ iperf3 -c 192.168.1.100 Connecting to host 192.168.1.100, port 5201 [ 4] local 192.168.1.206 port 52832 connected to 192.168.1.100 port 5201 [ ID] Interval Transfer Bandwidth Retr Cwnd [ 4] 0.00-1.01 sec 99.5 MBytes 829 Mbits/sec 117 139 KBytes [ 4] 1.01-2.00 sec 105 MBytes 884 Mbits/sec 129 70.7 KBytes [ 4] 2.00-3.01 sec 107 MBytes 889 Mbits/sec 106 187 KBytes [ 4] 3.01-4.01 sec 105 MBytes 878 Mbits/sec 92 143 KBytes [ 4] 4.01-5.00 sec 105 MBytes 882 Mbits/sec 140 129 KBytes [ 4] 5.00-6.01 sec 106 MBytes 883 Mbits/sec 115 195 KBytes [ 4] 6.01-7.00 sec 102 MBytes 863 Mbits/sec 133 70.7 KBytes [ 4] 7.00-8.01 sec 106 MBytes 884 Mbits/sec 143 97.6 KBytes [ 4] 8.01-9.01 sec 104 MBytes 875 Mbits/sec 124 107 KBytes [ 4] 9.01-10.01 sec 105 MBytes 876 Mbits/sec 90 139 KBytes - - - - - - - - - - - - - - - - - - - - - - - - - [ ID] Interval Transfer Bandwidth Retr [ 4] 0.00-10.01 sec 1.02 GBytes 874 Mbits/sec 1189 sender [ 4] 0.00-10.01 sec 1.02 GBytes 873 Mbits/sec receiver iperf Done. I get similar TX throughput on my Meson GXBB "MXQ Pro+" board when I disable the PHY's TX-delay and configure a 4ms TX-delay on the MAC. So changes to at least the RTL8211F PHY driver are needed to get it working properly in all situations. Changes since v2: - moved all .dts patches (3-7) to a separate series - removed the default 2ns TX delay when phy-mode RGMII is specified - (rebased against current net-next) Changes since v1: - renamed the devicetree property "amlogic,tx-delay" to "amlogic,tx-delay-ns", which makes the .dts easier to read as we can simply specify human-readable values instead of having "preprocessor defines and calculation in human brain". Thanks to Andrew Lunn for the suggestion! - improved documentation to indicate when the MAC TX-delay should be configured and how to use the PHY's TX-delay - changed the default TX-delay in the dwmac-meson8b driver from 2ns to 0ms when any of the rgmii-*id modes are used (the 2ns default value still applies for phy-mode "rgmii") - added patches to properly reset the PHY on Meson GXBB devices and to use a similar configuration than the one we use on Meson GXL devices (by passing a phy-handle to stmmac and defining the PHY in the mdio0 bus - patch 3-6) - add the "amlogic,tx-delay-ns" property to all boards which are using the RGMII PHY (patch 7) Martin Blumenstingl (2): net: dt-bindings: add RGMII TX delay configuration to meson8b-dwmac net: stmmac: dwmac-meson8b: make the RGMII TX delay configurable .../devicetree/bindings/net/meson-dwmac.txt | 14 ++++++++++++++ drivers/net/ethernet/stmicro/stmmac/dwmac-meson8b.c | 21 +++++++++++++++------ 2 files changed, 29 insertions(+), 6 deletions(-) -- 2.10.2 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
