net/mlx4_core: Avoid setting ports to auto when only one port type is supported

When only one port type is supported, it should be read only.
We reject changing requests, even to the auto sense mode.

Fixes: 27bf91d6a0d5 ("mlx4_core: Add link type autosensing")
Signed-off-by: Maor Gottlieb <maorg@mellanox.com>
Signed-off-by: Moshe Shemesh <moshe@mellanox.com>
Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlx4/main.c

@@ -1102,6 +1102,14 @@ static int __set_port_type(struct mlx4_port_info *info,
 	int i;
 	int err = 0;
 
+	if ((port_type & mdev->caps.supported_type[info->port]) != port_type) {
+		mlx4_err(mdev,
+			 "Requested port type for port %d is not supported on this HCA\n",
+			 info->port);
+		err = -EINVAL;
+		goto err_sup;
+	}
+
 	mlx4_stop_sense(mdev);
 	mutex_lock(&priv->port_mutex);
 	info->tmp_type = port_type;
@@ -1147,7 +1155,7 @@ static int __set_port_type(struct mlx4_port_info *info,
 out:
 	mlx4_start_sense(mdev);
 	mutex_unlock(&priv->port_mutex);
-
+err_sup:
 	return err;
 }