[U-Boot] imx8mq-evk: Outbound network packets lost

[Chris Spencer]

On Wed, 30 Jan 2019 at 00:44, Sergey Kubushyn <ksi at koi8.net> wrote:
> OK, I've got it working. The problem was DM FEC driver does _NOT_ do pin
> muxing and FEC pins in i.MX8MQ come up as GPIOs after rest so no wonder it
> can't talk to the PHY or whatever else.
>
> I don't know yet if there is some setting that I've missed to force it to do
> pin muxing but didn't find anything appropriate in reference fsl-imx8mq-evk
> board configs or board source files.
>
> Once pin muxing is done in the board file FEC comes up as expected, finds
> the PHY and all network stuff works as expected.
>
> Dedicated "regulator" and PHY reset works OK from DTB provided FEC driver is
> patched for regulator (regulator_set_enable instead of regulator_autoset)
> and PHY reset GPIO set "ACTIVE_LOW" in the board's DTS file (fec driver sets
> it to "1" to reset then resets it to "0").
>
> So it is either pin muxing is missing and one should do it in his board's
> file or I've missed some setting that I can't find to get the DM FEC driver
> to do it itself from DTS file.

Welp. There's no pinctrl driver. That would explain a lot...

The attached patches fix the networking in U-Boot for me (I can at
least ping; haven't tried anything else). If it works for you then I
will submit the patches properly with your Tested-by.

Weirdly, I still get the issue in Linux where it intermittently uses
the wrong phy driver, but, with this change, the generic phy driver
now seems to work fine. I guess maybe U-Boot is now leaving the phy in
a different state that happens to work.

Chris
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