[PATCH 0/5] meson-gx: reset RGMII PHYs and configure TX delay

[Martin Blumenstingl]

On Tue, Jan 17, 2017 at 8:23 PM, Jerome Brunet <jbrunet at baylibre.com> wrote:
> On Sat, 2016-12-03 at 00:47 +0100, Martin Blumenstingl wrote:
>> This partially fixes the 1000Mbit/s ethernet TX throughput issues (on
>> networks which are not affected by the EEE problem, as reported here:
>> [1]).
>> The actual problem for the TX throughput issues was that the TX delay
>> was applied twice:
>> - once "accidentally" by the PHY (this was fixed with [2])
>> - once by the MAC because there was a hardcoded TX delay (of 2ns),
>>   this will be configurable with the changes from [0]
>>
>> These are the dts changes which belong to my other series (in v2
>> these patches were part of the other series, upon request of the
>> net maintainers I have split the .dts changes into their own series
>> so
>> we are able to take both through different trees):
>> "[PATCH net-next v3 0/2] stmmac: dwmac-meson8b: configurable
>> RGMII TX delay": [0].
>> Thus this series depends on the ACK for the binding changes in the
>> other series!
>>
>> I based these changes on my other series "[PATCH v2 0/2] GXL and GXM
>> SCPI improvements": [3]
>>
>>
>> [0] http://lists.infradead.org/pipermail/linux-amlogic/2016-December/
>> 001834.html
>> [1] http://lists.infradead.org/pipermail/linux-amlogic/2016-November/
>> 001607.html
>> [2] http://lists.infradead.org/pipermail/linux-amlogic/2016-November/
>> 001707.html
>> [3] http://lists.infradead.org/pipermail/linux-amlogic/2016-December/
>> 001831.html
>>
>> Martin Blumenstingl (5):
>>   ARM64: dts: meson-gx: move the MDIO node to meson-gx
>
> Sorry for the late reply, I've only been able to test this yesterday.
>
> With "snps,dwmac-mdio" provided in meson-gx.dtsi, the mdio_node is
> defined in stmmac_mdio_register and auto-detection of the PHY is
> disabled for all meson-gx boards.
>
> I wonder if this is desirable ? or maybe this something we could fix in
> stmmac ? (perform auto-detect the mdio bus is provided without a PHY)
actually it's only a "problem" when introducing support for new
devices. can you please forward this question to the stmmac
maintainers, as I think your idea of enabling auto-detection when
there are no children in the MDIO-bus makes sense

> Also, I think bisect is broken between patch 1 and patch 4: The PHY of
> some boards won't be detected between these patches. Should we squash
> them ?
what do you mean exactly? currently the TX-delay is hardcoded in
dwmac-meson8b. patch 4 moves the hardcoded value from the
dwmac-meson8b to the .dts-files.
unfortunately the corresponding dwmac-meson8b patch was not accepted
yet, so at the moment patch 4 should be a no-op.

>>   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
>>
>
> Last remark, about the use of ethernet-phy-idXXXX.XXXX in the odroid
> and the vega: Isn't it better to let phylib do the autodetection of the
> phy id ?
>
> If we want to specify the id in DT, we should probably add it for the
> Micrel PHY of the p200 as well, for consistency.
this seems to be a "best practice" when the PHY ID is known, see [0]
If you know the PHY ID of the Micrel PHY then please let me know, then
we can include this in the fix for the p20x boards

>>  arch/arm64/boot/dts/amlogic/meson-gx.dtsi            |  6 ++++++
>>  arch/arm64/boot/dts/amlogic/meson-gxbb-odroidc2.dts  | 17
>> +++++++++++++++++
>>  arch/arm64/boot/dts/amlogic/meson-gxbb-p20x.dtsi     | 17
>> +++++++++++++++++
>>  arch/arm64/boot/dts/amlogic/meson-gxbb-vega-s95.dtsi | 17
>> +++++++++++++++++
>>  arch/arm64/boot/dts/amlogic/meson-gxl-s905d-p230.dts |  2 ++
>>  arch/arm64/boot/dts/amlogic/meson-gxl.dtsi           |  6 ------
>>  arch/arm64/boot/dts/amlogic/meson-gxm-nexbox-a1.dts  |  2 ++
>>  arch/arm64/boot/dts/amlogic/meson-gxm-s912-q200.dts  |  2 ++
>>  8 files changed, 63 insertions(+), 6 deletions(-)
>>

[0] http://lxr.free-electrons.com/source/Documentation/devicetree/bindings/net/phy.txt#L22