[PATCH net] net: dsa: mv88e6xxx: fix in-band AN link establishment

[David Miller]

From: Russell King <rmk+kernel at armlinux.org.uk>
Date: Sun, 19 Jul 2020 12:00:35 +0100

> If in-band negotiation or fixed-link modes are specified for a DSA
> port, the DSA code will force the link down during initialisation. For
> fixed-link mode, this is fine, as phylink will manage the link state.
> However, for in-band mode, phylink expects the PCS to detect link,
> which will not happen if the link is forced down.
> 
> There is a related issue that in in-band mode, the link could come up
> while we are making configuration changes, so we should force the link
> down prior to reconfiguring the interface mode.
> 
> This patch addresses both issues.
> 
> Fixes: 3be98b2d5fbc ("net: dsa: Down cpu/dsa ports phylink will control")
> Signed-off-by: Russell King <rmk+kernel at armlinux.org.uk>

Applied and queued up for -stable,  but:

> @@ -664,6 +664,7 @@ static void mv88e6xxx_mac_config(struct dsa_switch *ds, int port,
>  				 const struct phylink_link_state *state)
>  {
>  	struct mv88e6xxx_chip *chip = ds->priv;
> +	struct mv88e6xxx_port *p = &chip->ports[port];
>  	int err;

I fixed the reverse christmas tree breakage here by moving the 'p'
assignment into the function body.