net: dsa: add plumbing for changing and getting MAC merge layer state

The DSA core is in charge of the ethtool_ops of the net devices
associated with switch ports, so in case a hardware driver supports the
MAC merge layer, DSA must pass the callbacks through to the driver.
Add support for precisely that.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/dsa.h

@@ -937,6 +937,17 @@ struct dsa_switch_ops {
 	int	(*get_ts_info)(struct dsa_switch *ds, int port,
 			       struct ethtool_ts_info *ts);
 
+	/*
+	 * ethtool MAC merge layer
+	 */
+	int	(*get_mm)(struct dsa_switch *ds, int port,
+			  struct ethtool_mm_state *state);
+	int	(*set_mm)(struct dsa_switch *ds, int port,
+			  struct ethtool_mm_cfg *cfg,
+			  struct netlink_ext_ack *extack);
+	void	(*get_mm_stats)(struct dsa_switch *ds, int port,
+				struct ethtool_mm_stats *stats);
+
 	/*
 	 * DCB ops
 	 */

net/dsa/slave.c

@@ -1117,6 +1117,40 @@ static void dsa_slave_net_selftest(struct net_device *ndev,
 	net_selftest(ndev, etest, buf);
 }
 
+static int dsa_slave_get_mm(struct net_device *dev,
+			    struct ethtool_mm_state *state)
+{
+	struct dsa_port *dp = dsa_slave_to_port(dev);
+	struct dsa_switch *ds = dp->ds;
+
+	if (!ds->ops->get_mm)
+		return -EOPNOTSUPP;
+
+	return ds->ops->get_mm(ds, dp->index, state);
+}
+
+static int dsa_slave_set_mm(struct net_device *dev, struct ethtool_mm_cfg *cfg,
+			    struct netlink_ext_ack *extack)
+{
+	struct dsa_port *dp = dsa_slave_to_port(dev);
+	struct dsa_switch *ds = dp->ds;
+
+	if (!ds->ops->set_mm)
+		return -EOPNOTSUPP;
+
+	return ds->ops->set_mm(ds, dp->index, cfg, extack);
+}
+
+static void dsa_slave_get_mm_stats(struct net_device *dev,
+				   struct ethtool_mm_stats *stats)
+{
+	struct dsa_port *dp = dsa_slave_to_port(dev);
+	struct dsa_switch *ds = dp->ds;
+
+	if (ds->ops->get_mm_stats)
+		ds->ops->get_mm_stats(ds, dp->index, stats);
+}
+
 static void dsa_slave_get_wol(struct net_device *dev, struct ethtool_wolinfo *w)
 {
 	struct dsa_port *dp = dsa_slave_to_port(dev);
@@ -2205,6 +2239,9 @@ static const struct ethtool_ops dsa_slave_ethtool_ops = {
 	.set_rxnfc		= dsa_slave_set_rxnfc,
 	.get_ts_info		= dsa_slave_get_ts_info,
 	.self_test		= dsa_slave_net_selftest,
+	.get_mm			= dsa_slave_get_mm,
+	.set_mm			= dsa_slave_set_mm,
+	.get_mm_stats		= dsa_slave_get_mm_stats,
 };
 
 static const struct dcbnl_rtnl_ops __maybe_unused dsa_slave_dcbnl_ops = {