mlxsw: spectrum: Add support for physical port names

Export to userspace the front panel name of the port, so that udev can
rename the ports accordingly. The convention suggested by switchdev
documentation is used:

1) Non-split: pX
2) Split: pXsY
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlxsw/spectrum.c

@@ -305,9 +305,9 @@ mlxsw_sp_port_system_port_mapping_set(struct mlxsw_sp_port *mlxsw_sp_port)
 	return mlxsw_reg_write(mlxsw_sp->core, MLXSW_REG(sspr), sspr_pl);
 }
 
-static int mlxsw_sp_port_module_info_get(struct mlxsw_sp *mlxsw_sp,
-					 u8 local_port, u8 *p_module,
-					 u8 *p_width)
+static int __mlxsw_sp_port_module_info_get(struct mlxsw_sp *mlxsw_sp,
+					   u8 local_port, u8 *p_module,
+					   u8 *p_width, u8 *p_lane)
 {
 	char pmlp_pl[MLXSW_REG_PMLP_LEN];
 	int err;
@@ -318,9 +318,20 @@ static int mlxsw_sp_port_module_info_get(struct mlxsw_sp *mlxsw_sp,
 		return err;
 	*p_module = mlxsw_reg_pmlp_module_get(pmlp_pl, 0);
 	*p_width = mlxsw_reg_pmlp_width_get(pmlp_pl);
+	*p_lane = mlxsw_reg_pmlp_tx_lane_get(pmlp_pl, 0);
 	return 0;
 }
 
+static int mlxsw_sp_port_module_info_get(struct mlxsw_sp *mlxsw_sp,
+					 u8 local_port, u8 *p_module,
+					 u8 *p_width)
+{
+	u8 lane;
+
+	return __mlxsw_sp_port_module_info_get(mlxsw_sp, local_port, p_module,
+					       p_width, &lane);
+}
+
 static int mlxsw_sp_port_module_map(struct mlxsw_sp *mlxsw_sp, u8 local_port,
 				    u8 module, u8 width, u8 lane)
 {
@@ -861,6 +872,33 @@ int mlxsw_sp_port_kill_vid(struct net_device *dev,
 	return 0;
 }
 
+static int mlxsw_sp_port_get_phys_port_name(struct net_device *dev, char *name,
+					    size_t len)
+{
+	struct mlxsw_sp_port *mlxsw_sp_port = netdev_priv(dev);
+	u8 module, width, lane;
+	int err;
+
+	err = __mlxsw_sp_port_module_info_get(mlxsw_sp_port->mlxsw_sp,
+					      mlxsw_sp_port->local_port,
+					      &module, &width, &lane);
+	if (err) {
+		netdev_err(dev, "Failed to retrieve module information\n");
+		return err;
+	}
+
+	if (!mlxsw_sp_port->split)
+		err = snprintf(name, len, "p%d", module + 1);
+	else
+		err = snprintf(name, len, "p%ds%d", module + 1,
+			       lane / width);
+
+	if (err >= len)
+		return -EINVAL;
+
+	return 0;
+}
+
 static const struct net_device_ops mlxsw_sp_port_netdev_ops = {
 	.ndo_open		= mlxsw_sp_port_open,
 	.ndo_stop		= mlxsw_sp_port_stop,
@@ -877,6 +915,7 @@ static const struct net_device_ops mlxsw_sp_port_netdev_ops = {
 	.ndo_bridge_setlink	= switchdev_port_bridge_setlink,
 	.ndo_bridge_getlink	= switchdev_port_bridge_getlink,
 	.ndo_bridge_dellink	= switchdev_port_bridge_dellink,
+	.ndo_get_phys_port_name	= mlxsw_sp_port_get_phys_port_name,
 };
 
 static void mlxsw_sp_port_get_drvinfo(struct net_device *dev,