Hello Russell,
> From: Russell King, Sent: Tuesday, January 3, 2023 6:56 PM
>
> On Mon, Dec 26, 2022 at 04:14:25PM +0900, Yoshihiro Shimoda wrote:
> > Some Ethernet PHYs (like marvell10g) will decide the host interface
> > mode by the media-side speed. So, the rswitch driver needs to
> > initialize one of the Ethernet SERDES (r8a779f0-eth-serdes) ports
> > after linked the Ethernet PHY up. The r8a779f0-eth-serdes driver has
> > .init() for initializing all ports and .power_on() for initializing
> > each port. So, add phy_power_{on,off} calling for it.
> >
> > Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx>
> > ---
> > drivers/net/ethernet/renesas/rswitch.c | 8 ++++++++
> > 1 file changed, 8 insertions(+)
> >
> > diff --git a/drivers/net/ethernet/renesas/rswitch.c b/drivers/net/ethernet/renesas/rswitch.c
> > index ca79ee168206..2f335c95f5a8 100644
> > --- a/drivers/net/ethernet/renesas/rswitch.c
> > +++ b/drivers/net/ethernet/renesas/rswitch.c
> > @@ -1180,6 +1180,10 @@ static void rswitch_mac_link_down(struct phylink_config *config,
> > unsigned int mode,
> > phy_interface_t interface)
> > {
> > + struct net_device *ndev = to_net_dev(config->dev);
> > + struct rswitch_device *rdev = netdev_priv(ndev);
> > +
> > + phy_power_off(rdev->serdes);
> > }
> >
> > static void rswitch_mac_link_up(struct phylink_config *config,
> > @@ -1187,7 +1191,11 @@ static void rswitch_mac_link_up(struct phylink_config *config,
> > phy_interface_t interface, int speed,
> > int duplex, bool tx_pause, bool rx_pause)
> > {
> > + struct net_device *ndev = to_net_dev(config->dev);
> > + struct rswitch_device *rdev = netdev_priv(ndev);
> > +
> > /* Current hardware cannot change speed at runtime */
> > + phy_power_on(rdev->serdes);
> > }
> >
> > static const struct phylink_mac_ops rswitch_phylink_ops = {
>
> This looks to me like it will break anyone using an in-band link,
> where the link status comes from the PCS behind the series that
> you're now powering down and up.
Thank you for your review!
To be honest, I didn't know about "an in-band link". So, I studied a little,
and then I might understand about your comments. However, I still don't
understand whether this hardware (rswitch) can support the "in-band link" or not.
This seems to need a special hardware feature for "in-band link" and
only software cannot support it, IIUC.
# Unfortunately, this hardware's datasheet cannot be in public for now though...
Anyway, I'll add a condition which this driver cannot support MLO_AN_INBAND
to avoid a problem by someone for now.
Best regards,
Yoshihiro Shimoda
