net: dsa: allow DSA switch drivers to provide their own phylink mac ops

Rather than having a shim for each and every phylink MAC operation,
allow DSA switch drivers to provide their own ops structure. When a
DSA driver provides the phylink MAC operations, the shimmed ops must
not be provided, so fail an attempt to register a switch with both
the phylink_mac_ops in struct dsa_switch and the phylink_mac_*
operations populated in dsa_switch_ops populated.

Signed-off-by: Russell King (Oracle) <[email protected]>
Reviewed-by: Vladimir Oltean <[email protected]>
Reviewed-by: Florian Fainelli <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

Author: Russell King (Oracle)

include/net/dsa.h

@@ -457,6 +457,11 @@ struct dsa_switch {
 	 */
 	const struct dsa_switch_ops	*ops;
 
+	/*
+	 * Allow a DSA switch driver to override the phylink MAC ops
+	 */
+	const struct phylink_mac_ops	*phylink_mac_ops;
+
 	/*
 	 * User mii_bus and devices for the individual ports.
 	 */

net/dsa/dsa.c

@@ -1505,6 +1505,17 @@ static int dsa_switch_probe(struct dsa_switch *ds)
 	if (!ds->num_ports)
 		return -EINVAL;
 
+	if (ds->phylink_mac_ops) {
+		if (ds->ops->phylink_mac_select_pcs ||
+		    ds->ops->phylink_mac_prepare ||
+		    ds->ops->phylink_mac_config ||
+		    ds->ops->phylink_mac_finish ||
+		    ds->ops->phylink_mac_link_down ||
+		    ds->ops->phylink_mac_link_up ||
+		    ds->ops->adjust_link)
+			return -EINVAL;
+	}
+
 	if (np) {
 		err = dsa_switch_parse_of(ds, np);
 		if (err)

net/dsa/port.c

@@ -1662,6 +1662,7 @@ static const struct phylink_mac_ops dsa_port_phylink_mac_ops = {
 
 int dsa_port_phylink_create(struct dsa_port *dp)
 {
+	const struct phylink_mac_ops *mac_ops;
 	struct dsa_switch *ds = dp->ds;
 	phy_interface_t mode;
 	struct phylink *pl;
@@ -1685,8 +1686,12 @@ int dsa_port_phylink_create(struct dsa_port *dp)
 		}
 	}
 
-	pl = phylink_create(&dp->pl_config, of_fwnode_handle(dp->dn),
-			    mode, &dsa_port_phylink_mac_ops);
+	mac_ops = &dsa_port_phylink_mac_ops;
+	if (ds->phylink_mac_ops)
+		mac_ops = ds->phylink_mac_ops;
+
+	pl = phylink_create(&dp->pl_config, of_fwnode_handle(dp->dn), mode,
+			    mac_ops);
 	if (IS_ERR(pl)) {
 		pr_err("error creating PHYLINK: %ld\n", PTR_ERR(pl));
 		return PTR_ERR(pl);
@@ -1952,12 +1957,23 @@ static void dsa_shared_port_validate_of(struct dsa_port *dp,
 		dn, dsa_port_is_cpu(dp) ? "CPU" : "DSA", dp->index);
 }
 
+static void dsa_shared_port_link_down(struct dsa_port *dp)
+{
+	struct dsa_switch *ds = dp->ds;
+
+	if (ds->phylink_mac_ops && ds->phylink_mac_ops->mac_link_down)
+		ds->phylink_mac_ops->mac_link_down(&dp->pl_config, MLO_AN_FIXED,
+						   PHY_INTERFACE_MODE_NA);
+	else if (ds->ops->phylink_mac_link_down)
+		ds->ops->phylink_mac_link_down(ds, dp->index, MLO_AN_FIXED,
+					       PHY_INTERFACE_MODE_NA);
+}
+
 int dsa_shared_port_link_register_of(struct dsa_port *dp)
 {
 	struct dsa_switch *ds = dp->ds;
 	bool missing_link_description;
 	bool missing_phy_mode;
-	int port = dp->index;
 
 	dsa_shared_port_validate_of(dp, &missing_phy_mode,
 				    &missing_link_description);
@@ -1973,9 +1989,7 @@ int dsa_shared_port_link_register_of(struct dsa_port *dp)
 				 "Skipping phylink registration for %s port %d\n",
 				 dsa_port_is_cpu(dp) ? "CPU" : "DSA", dp->index);
 		} else {
-			if (ds->ops->phylink_mac_link_down)
-				ds->ops->phylink_mac_link_down(ds, port,
-					MLO_AN_FIXED, PHY_INTERFACE_MODE_NA);
+			dsa_shared_port_link_down(dp);
 
 			return dsa_shared_port_phylink_register(dp);
 		}