On Fri, Nov 26, 2021 at 10:05:37AM +0100, Horatiu Vultur wrote:

This patch adds support for netdev and phylink in the switch. The
injection + extraction is register based. This will be replaced with DMA
accees.

Signed-off-by: Horatiu Vultur <horatiu.vultur@microchip.com>

This looks mostly good now, thanks. There's one remaining issue:

+int lan966x_port_pcs_set(struct lan966x_port *port,
+			 struct lan966x_port_config *config)
+{
+	struct lan966x *lan966x = port->lan966x;
+	bool inband_aneg = false;
+	bool outband;
+	int err;
+
+	lan966x_port_link_down(port);

This looks like something the MAC layer should be doing. Phylink won't
change the interface mode by just calling the PCS - it will do this
sequence, known as a major reconfiguration:

mac_link_down() (if the link was previously up)
mac_prepare()
mac_config()
if (pcs_config() > 0)
  pcs_an_restart()
mac_finish()

pcs_config() will also be called thusly:

if (pcs_config() > 0)
  pcs_an_restart()

to change the ethtool advertising mask which changes the inband advert
or the Autoneg bit, which has an effect only on your DEV_PCS1G_ANEG_CFG()
register, and this may be called with the link up or down.

Also, pcs_config() is supposed to return 0 if the inband advert has not
changed, or positive if it has (so pcs_an_restart() is called to cause
in-band negotiation to be restarted.)

Note also that pcs_an_restart() may  also be called when ethtool
requests negotiation restart when we're operating in 802.3z modes.

So, my question is - do you need to be so heavy weight with the call to
lan966x_port_link_down() to take everything down when pcs_config() is
called, and is it really in the right place through the sequence for
a major reconfiguration?

Thanks.

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