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Date:   Fri, 28 Jul 2023 11:44:16 +0300
From:   Ilias Apalodimas <ilias.apalodimas@linaro.org>
To:     Ard Biesheuvel <ardb@kernel.org>
Cc:     Mark Brown <broonie@kernel.org>,
        Masahisa Kojima <masahisa.kojima@linaro.org>,
        Jassi Brar <jaswinder.singh@linaro.org>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] net: netsec: Ignore 'phy-mode' on SynQuacer in DT mode
Message-ID: <ZMN/4F4TZZtt8B/b@hades>
References: <20230727-synquacer-net-v1-1-4d7f5c4cc8d9@kernel.org>
 <CAMj1kXH_4OEY58Nb9yGHTDvjfouJHKNVhReo0mMdD_aGWW_WGQ@mail.gmail.com>
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Hi Ard, Mark

On Fri, Jul 28, 2023 at 07:45:44AM +0200, Ard Biesheuvel wrote:
> (cc Masahisa)
> 
> On Thu, 27 Jul 2023 at 23:52, Mark Brown <broonie@kernel.org> wrote:
> >
> > As documented in acd7aaf51b20 ("netsec: ignore 'phy-mode' device
> > property on ACPI systems") the SocioNext SynQuacer platform ships with
> > firmware defining the PHY mode as RGMII even though the physical
> > configuration of the PHY is for TX and RX commits.  Since
> > bbc4d71d63549bc ("net: phy: realtek: fix rtl8211e rx/tx delay config")
> > this has caused misconfiguration of the PHY, rendering the network
> > unusable.
> >
> > This was worked around for ACPI by ignoring the phy-mode property but
> > the system is also used with DT.  Since the firmware used with DT is the
> > same (the firmware interface is selectable in the firmware
> > configuration) and the firmware configures the PHY prior to running the
> > OS we can use the same workaround.
> >
> 
> Wouldn't this break SynQuacers booting with firmware that lacks a
> network driver? (I.e., u-boot?)
> 

U-Boot does support the network interface (sni-netsec.c) but I'll have to
check what that code does wrt to the PHY config.  Since the interface works
I am assuming some config is done properly. 

> I am not sure why, but quite some effort has gone into porting u-boot
> to this SoC as well.

It was mostly an effort to prove the box is SystemReady-IR compliant.  On
top of that it was (back then) one of the few available platforms with an
RPMB interface and OP-TEE support, so it was used for demonstrating storing
EFI variables there. 

Regards
/Ilias
> 
> 
> > Limit this to the SynQuacer, though practically speaking this is the
> > only currently known system using this device.
> >
> > Fixes: 533dd11a12f6 ("net: socionext: Add Synquacer NetSec driver")
> > Signed-off-by: Mark Brown <broonie@kernel.org>
> > ---
> >  drivers/net/ethernet/socionext/netsec.c | 18 ++++++++++++++----
> >  1 file changed, 14 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/net/ethernet/socionext/netsec.c b/drivers/net/ethernet/socionext/netsec.c
> > index 2d7347b71c41..ae4d336efaa4 100644
> > --- a/drivers/net/ethernet/socionext/netsec.c
> > +++ b/drivers/net/ethernet/socionext/netsec.c
> > @@ -1845,10 +1845,20 @@ static int netsec_of_probe(struct platform_device *pdev,
> >  {
> >         int err;
> >
> > -       err = of_get_phy_mode(pdev->dev.of_node, &priv->phy_interface);
> > -       if (err) {
> > -               dev_err(&pdev->dev, "missing required property 'phy-mode'\n");
> > -               return err;
> > +       if (of_machine_is_compatible("socionext,developer-box")) {
> > +               /*
> > +                * SynQuacer reports RGMII but is physically
> > +                * configured with TX and RX delays, since the
> > +                * firwmare configures the PHY prior to boot just
> > +                * ignore the configuration.
> > +                */
> > +               priv->phy_interface = PHY_INTERFACE_MODE_NA;
> > +       } else {
> > +               err = of_get_phy_mode(pdev->dev.of_node, &priv->phy_interface);
> > +               if (err) {
> > +                       dev_err(&pdev->dev, "missing required property 'phy-mode'\n");
> > +                       return err;
> > +               }
> >         }
> >
> >         priv->phy_np = of_parse_phandle(pdev->dev.of_node, "phy-handle", 0);
> >
> > ---
> > base-commit: 6eaae198076080886b9e7d57f4ae06fa782f90ef
> > change-id: 20230727-synquacer-net-e241f34baceb
> >
> > Best regards,
> > --
> > Mark Brown <broonie@kernel.org>
> >