[PATCH v2 0/7] stmmac: dwmac-meson8b: configurable RGMII TX delay

[narmstrong@baylibre.com (Neil Armstrong)]

On 11/25/2016 02:01 PM, 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...
> 
> 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.
> 
> 
> NOTE: patches 3-7 should be taken though the Amlogic tree. patches 1
> and 2 can be taken through the net-tree or through the Amlogic tree.
> There shouldn't be a runtime dependency as long as phy-mode "rgmii"
> (or the not-relevant-for-this-case "rmii") is used (which is currently
> the case for all ARM64 meson-gx boards) due to the dwmac-meson8b's
> default 2ns TX-delay.
> 
> 
> 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 (7):
>   net: dt-bindings: add RGMII TX delay configuration to meson8b-dwmac
>   net: stmmac: dwmac-meson8b: make the RGMII TX delay configurable
>   ARM64: dts: meson-gx: move the MDIO node to meson-gx
>   ARM64: dts: meson-gxbb-odroidc2: add reset for the ethernet PHY
>   ARM64: dts: meson-gxbb-p20x: add reset for the ethernet PHY
>   ARM64: dts: meson-gxbb-vega-s95: add reset for the ethernet PHY
>   ARM64: dts: amlogic: add the ethernet TX delay configuration
> 
>  .../devicetree/bindings/net/meson-dwmac.txt        | 14 ++++++++++++
>  arch/arm64/boot/dts/amlogic/meson-gx.dtsi          |  6 +++++
>  .../arm64/boot/dts/amlogic/meson-gxbb-odroidc2.dts | 17 ++++++++++++++
>  arch/arm64/boot/dts/amlogic/meson-gxbb-p20x.dtsi   | 17 ++++++++++++++
>  .../boot/dts/amlogic/meson-gxbb-vega-s95.dtsi      | 17 ++++++++++++++
>  .../boot/dts/amlogic/meson-gxl-s905d-p230.dts      |  2 ++
>  arch/arm64/boot/dts/amlogic/meson-gxl.dtsi         |  6 -----
>  .../arm64/boot/dts/amlogic/meson-gxm-nexbox-a1.dts |  2 ++
>  .../arm64/boot/dts/amlogic/meson-gxm-s912-q200.dts |  2 ++
>  .../net/ethernet/stmicro/stmmac/dwmac-meson8b.c    | 26 +++++++++++++++++-----
>  10 files changed, 97 insertions(+), 12 deletions(-)
> 

Along the "net: phy: realtek: fix RTL8211F TX-delay handling" v1 patchset,
fixes the link issue on my Nexbox A1 board and does not break my Amlogic P230 board.

Tested-by: Neil Armstrong <narmstrong@baylibre.com>