U-Boot and ethernet regression on mx6cuboxi

[Tom Rini]

On Thu, Apr 28, 2022 at 02:25:03PM -0700, Tim Harvey wrote:
> On Thu, Apr 28, 2022 at 1:41 PM Tom Rini <trini at konsulko.com> wrote:
> >
> > Hey,
> >
> > So my mx6cuboxi was out of my lab for a bit, and that's how this
> > regression got in mainline.  With:
> > 4223fb0ee18d11462c55ac94198fdc2055f2c27c is the first bad commit
> > commit 4223fb0ee18d11462c55ac94198fdc2055f2c27c
> > Author: Tim Harvey <tharvey at gateworks.com>
> > Date:   Tue Mar 1 12:15:01 2022 -0800
> >
> >     net: fec: prevent undesired de-assertion of phy-reset on request
> >
> > I now see:
> > => dhcp
> > ethernet at 2188000 Waiting for PHY auto negotiation to complete......... TIMEOUT !
> > Could not initialize PHY ethernet at 2188000
> > BOOTP broadcast 1
> > BOOTP broadcast 2
> > BOOTP broadcast 3
> > BOOTP broadcast 4
> > BOOTP broadcast 5
> > BOOTP broadcast 6
> > BOOTP broadcast 7
> > BOOTP broadcast 8
> > BOOTP broadcast 9
> > BOOTP broadcast 10
> > BOOTP broadcast 11
> > BOOTP broadcast 12
> > BOOTP broadcast 13
> > BOOTP broadcast 14
> > BOOTP broadcast 15
> > BOOTP broadcast 16
> >
> > Any ideas?  Thanks!
> >
> 
> Tom,
> 
> What PHY is used on that board and can you verify the PHY reset is
> properly defined in the dt polarity and all?
> 
> What I found is that before commit 4223fb0ee18d11 ("net: fec: prevent
> undesired de-assertion of phy-reset on request") my board's
> (imx8mm-venice-gw73xx) PHY_RST would driver high during the
> gpio-request before it was driven low then high again. The PHY used on
> my board (at least new revisions) is the MaxLinear GPY111 and we it
> was extremely sensitive to multiple reset events and this behavior
> would make it unreliable.

Thanks for the hint, Tim!  Fabio, the dts needs to be re-synced with
Linux as upstream it says:
        /*
         * The PHY seems to require a long-enough reset duration to avoid
         * some rare issues where the PHY gets stuck in an inconsistent and
         * non-functional state at boot-up. 10ms proved to be fine .
         */
        phy-reset-duration = <10>;

But we have this set to 2, and indeed bumping it up to 10 to match fixes
the network tests for me.

-- 
Tom
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