Re: Aquantia PHY in OCSGMII mode?

["Russell King (Oracle)" <linux@armlinux.org.uk>]

On Fri, Aug 01, 2025 at 02:06:16PM +0200, Alexander Wilhelm wrote:
> Am Fri, Aug 01, 2025 at 12:58:23PM +0100 schrieb Russell King (Oracle):
> > On Fri, Aug 01, 2025 at 01:54:29PM +0200, Alexander Wilhelm wrote:
> > > Am Fri, Aug 01, 2025 at 02:01:06PM +0300 schrieb Vladimir Oltean:
> > > > On Thu, Jul 31, 2025 at 08:26:43PM +0100, Russell King (Oracle) wrote:
> > > > > and this works. So... we could actually reconfigure the PHY independent
> > > > > of what was programmed into the firmware.
> > > > 
> > > > It does work indeed, the trouble will be adding this code to the common
> > > > mainline kernel driver and then watching various boards break after their
> > > > known-good firmware provisioning was overwritten, from a source of unknown
> > > > applicability to their system.
> > > 
> > > You're right. I've now selected a firmware that uses a different provisioning
> > > table, which already configures the PHY for 2500BASE-X with Flow Control.
> > > According to the documentation, it should support all modes: 10M, 100M, 1G, and
> > > 2.5G.
> > > 
> > > It seems the issue lies with the MAC, as it doesn't appear to handle the
> > > configured PHY_INTERFACE_MODE_2500BASEX correctly. I'm currently investigating
> > > this further.
> > 
> > Which MAC driver, and is it using phylink?
> 
> If I understand it correclty, then yes. It is an Freescale FMAN driver that is
> called through phylink callbacks like the following:
> 
>     static const struct phylink_mac_ops memac_mac_ops = {
>             .validate = memac_validate,
>             .mac_select_pcs = memac_select_pcs,
>             .mac_prepare = memac_prepare,
>             .mac_config = memac_mac_config,
>             .mac_link_up = memac_link_up,
>             .mac_link_down = memac_link_down,
>     };

Thanks.

It looks like memac_select_pcs() and memac_prepare() fail to
handle 2500BASEX despite memac_initialization() suggesting the
SGMII PCS supports 2500BASEX.

It would also be good if the driver can also use
pcs->supported_interfaces which states which modes the PCS layer
supports as well.

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