Re: [RESEND PATCH net-next v3 3/4] net: phy: aquantia: wait for the GLOBAL_CFG to start returning real values

[Jon Hunter]

On 18/07/2024 14:29, Bartosz Golaszewski wrote:
> On Thu, Jul 18, 2024 at 3:04 PM Bartosz Golaszewski <brgl@xxxxxxxx> wrote:
> > On Thu, Jul 18, 2024 at 2:23 PM Jon Hunter <jonathanh@xxxxxxxxxx> wrote:
> > > With the current -next and mainline we are seeing the following issue on
> > > our Tegra234 Jetson AGX Orin platform ...
> > >
> > >    Aquantia AQR113C stmmac-0:00: aqr107_fill_interface_modes failed: -110
> > >    tegra-mgbe 6800000.ethernet eth0: __stmmac_open: Cannot attach to PHY (error: -110)
> > >
> > >
> > > We have tracked it down to this change and looks like our PHY does not
> > > support 10M ...
> > >
> > > $ ethtool eth0
> > > Settings for eth0:
> > >           Supported ports: [  ]
> > >           Supported link modes:   100baseT/Full
> > >                                   1000baseT/Full
> > >                                   10000baseT/Full
> > >                                   1000baseKX/Full
> > >                                   10000baseKX4/Full
> > >                                   10000baseKR/Full
> > >                                   2500baseT/Full
> > >                                   5000baseT/Full
> > >
> > > The following fixes this for this platform ...
> > >
> > > diff --git a/drivers/net/phy/aquantia/aquantia_main.c b/drivers/net/phy/aquantia/aquantia_main.c
> > > index d12e35374231..0b2db486d8bd 100644
> > > --- a/drivers/net/phy/aquantia/aquantia_main.c
> > > +++ b/drivers/net/phy/aquantia/aquantia_main.c
> > > @@ -656,7 +656,7 @@ static int aqr107_fill_interface_modes(struct phy_device *phydev)
> > >           int i, val, ret;
> > >
> > >           ret = phy_read_mmd_poll_timeout(phydev, MDIO_MMD_VEND1,
> > > -                                       VEND1_GLOBAL_CFG_10M, val, val != 0,
> > > +                                       VEND1_GLOBAL_CFG_100M, val, val != 0,
> > >                                           1000, 100000, false);
> > >           if (ret)
> > >                   return ret;
> > >
> > >
> > > However, I am not sure if this is guaranteed to work for all?
> >
> > Ah cr*p. No, I don't think it is. We should take the first supported
> > mode for a given PHY I think.
>
> TBH I only observed the issue on AQR115C. I don't have any other model
> to test with. Is it fine to fix it by implementing
> aqr115_fill_interface_modes() that would first wait for this register
> to return non-0 and then call aqr107_fill_interface_modes()?

I am doing a bit more testing. We have seen a few issues with this PHY 
driver and so I am wondering if we also need something similar for the 
AQR113C variant too.

Interestingly, the product brief for these PHYs [0] do show that both 
the AQR113C and AQR115C both support 10M. So I wonder if it is our 
ethernet controller that is not supporting 10M? I will check on this too.

Jon

[0] 
https://www.marvell.com/content/dam/marvell/en/public-collateral/transceivers/marvell-phys-transceivers-aqrate-gen4-product-brief.pdf


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