CPSW_WR_C_TX_EN
bus_space_write_4(sc->sc_bst, sc->sc_bsh, CPSW_WR_C_TX_EN(0), 1);
bus_space_write_4(sc->sc_bst, sc->sc_bsh, CPSW_WR_C_TX_EN(0), 0x0);