[net-next PATCH v1 0/2] stmmac: dwmac-meson8b: configurable RGMII TX delay
Jerome Brunet
jbrunet at baylibre.com
Thu Nov 24 08:08:01 PST 2016
On Thu, 2016-11-24 at 15:34 +0100, Martin Blumenstingl wrote:
> Currently the dwmac-meson8b stmmac glue driver uses a hardcoded 1/4
> cycle 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...
>
> This raises a question though:
> Which device is supposed to enable the TX delay when both MAC and PHY
> support it? And should we implement it for each PHY / MAC separately
> or should we think about a more generic solution (currently it's not
> possible to disable the TX delay generated by the RTL8211F PHY via
> devicetree when using phy-mode "rgmii")?
>
> 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
>
Cool, one more board working ;)
I tried your patch on another board (MXQ_V2.1, with sheep printed on
the PCB). It 's not improving the situation for this one unfortunately.
Actually I already tried playing with the TX delay on the MAC and PHY
but I could get any good results with the boards I have.
It is strange that we can adjust the delay by 2ns steps, when delay
seens by the phy should be 2ns ...
> iperf Done.
>
>
> Martin Blumenstingl (2):
> net: dt-bindings: add RGMII TX delay configuration to meson8b-dwmac
> net: stmmac: dwmac-meson8b: make the RGMII TX delay configurable
>
> Documentation/devicetree/bindings/net/meson-dwmac.txt | 11
> +++++++++++
> drivers/net/ethernet/stmicro/stmmac/dwmac-meson8b.c | 16
> +++++++++++-----
> include/dt-bindings/net/dwmac-meson8b.h | 18
> ++++++++++++++++++
> 3 files changed, 40 insertions(+), 5 deletions(-)
> create mode 100644 include/dt-bindings/net/dwmac-meson8b.h
>
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