mlxsw: spectrum_router: Configure TIGCR on init

Spectrum tunnels do not default to ttl of "inherit" like the Linux ones
do. Configure TIGCR on router init so that the TTL of tunnel packets is
copied from the overlay packets.

Fixes: ee954d1a91 ("mlxsw: spectrum_router: Support GRE tunnels")
Signed-off-by: Petr Machata <petrm@mellanox.com>
Reviewed-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_router.c

@@ -5896,11 +5896,20 @@ static void mlxsw_sp_rifs_fini(struct mlxsw_sp *mlxsw_sp)
 	kfree(mlxsw_sp->router->rifs);
 }
 
+static int
+mlxsw_sp_ipip_config_tigcr(struct mlxsw_sp *mlxsw_sp)
+{
+	char tigcr_pl[MLXSW_REG_TIGCR_LEN];
+
+	mlxsw_reg_tigcr_pack(tigcr_pl, true, 0);
+	return mlxsw_reg_write(mlxsw_sp->core, MLXSW_REG(tigcr), tigcr_pl);
+}
+
 static int mlxsw_sp_ipips_init(struct mlxsw_sp *mlxsw_sp)
 {
 	mlxsw_sp->router->ipip_ops_arr = mlxsw_sp_ipip_ops_arr;
 	INIT_LIST_HEAD(&mlxsw_sp->router->ipip_list);
-	return 0;
+	return mlxsw_sp_ipip_config_tigcr(mlxsw_sp);
 }
 
 static void mlxsw_sp_ipips_fini(struct mlxsw_sp *mlxsw_sp)