Re: [PATCH RFC net-next 3/6] net: dsa: sja1105: use .mac_select_pcs() interface

[Vladimir Oltean <olteanv@gmail.com>]

On Thu, Feb 24, 2022 at 04:15:26PM +0000, Russell King (Oracle) wrote:
> Convert the PCS selection to use mac_select_pcs, which allows the PCS
> to perform any validation it needs, and removes the need to set the PCS
> in the mac_config() callback, delving into the higher DSA levels to do
> so.
> 
> Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
> ---

Reviewed-by: Vladimir Oltean <olteanv@gmail.com>

>  drivers/net/dsa/sja1105/sja1105_main.c | 16 +++++++---------
>  1 file changed, 7 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/net/dsa/sja1105/sja1105_main.c b/drivers/net/dsa/sja1105/sja1105_main.c
> index e278bd86e3c6..b5c36f808df1 100644
> --- a/drivers/net/dsa/sja1105/sja1105_main.c
> +++ b/drivers/net/dsa/sja1105/sja1105_main.c
> @@ -1358,18 +1358,16 @@ static int sja1105_adjust_port_config(struct sja1105_private *priv, int port,
>  	return sja1105_clocking_setup_port(priv, port);
>  }
>  
> -static void sja1105_mac_config(struct dsa_switch *ds, int port,
> -			       unsigned int mode,
> -			       const struct phylink_link_state *state)
> +static struct phylink_pcs *
> +sja1105_mac_select_pcs(struct dsa_switch *ds, int port, phy_interface_t iface)
>  {
> -	struct dsa_port *dp = dsa_to_port(ds, port);
>  	struct sja1105_private *priv = ds->priv;
> -	struct dw_xpcs *xpcs;
> -
> -	xpcs = priv->xpcs[port];
> +	struct dw_xpcs *xpcs = priv->xpcs[port];
>  
>  	if (xpcs)
> -		phylink_set_pcs(dp->pl, &xpcs->pcs);
> +		return &xpcs->pcs;
> +
> +	return NULL;
>  }
>  
>  static void sja1105_mac_link_down(struct dsa_switch *ds, int port,
> @@ -3137,7 +3135,7 @@ static const struct dsa_switch_ops sja1105_switch_ops = {
>  	.port_max_mtu		= sja1105_get_max_mtu,
>  	.phylink_get_caps	= sja1105_phylink_get_caps,
>  	.phylink_validate	= sja1105_phylink_validate,
> -	.phylink_mac_config	= sja1105_mac_config,

Deleting sja1105_mac_config() here is safe not because
phylink_mac_config() stops calling pl->mac_ops->mac_config(), but
because dsa_port_phylink_mac_config() first checks whether
ds->ops->phylink_mac_config is implemented, and that is purely an
artefact of providing a phylib-style ds->ops->adjust_link, right?

Maybe it's worth mentioning.

> +	.phylink_mac_select_pcs	= sja1105_mac_select_pcs,
>  	.phylink_mac_link_up	= sja1105_mac_link_up,
>  	.phylink_mac_link_down	= sja1105_mac_link_down,
>  	.get_strings		= sja1105_get_strings,
> -- 
> 2.30.2
>