CPSW_CPDMA_TX_HDP
bus_space_write_4(sc->sc_bst, sc->sc_bsh, CPSW_CPDMA_TX_HDP(0), 0);
if (bus_space_read_4(sc->sc_bst, sc->sc_bsh, CPSW_CPDMA_TX_HDP(0)) == 0) {
bus_space_write_4(sc->sc_bst, sc->sc_bsh, CPSW_CPDMA_TX_HDP(0),
stat = bus_space_read_4(sc->sc_bst, sc->sc_bsh, CPSW_CPDMA_TX_HDP(0));
bus_space_write_4(sc->sc_bst, sc->sc_bsh, CPSW_CPDMA_TX_HDP(0),
bus_space_write_4(sc->sc_bst, sc->sc_bsh, CPSW_CPDMA_TX_HDP(i), 0);