LDN_TXDMA
nep_write(sc, LD_IM0(LDN_TXDMA(sc->sc_port)), 0);
nep_write(sc, LD_IM0(LDN_TXDMA(sc->sc_port)), 1);
nep_write(sc, LDG_NUM(LDN_TXDMA(sc->sc_port)), sc->sc_port);
if (sv0 & (1ULL << LDN_TXDMA(sc->sc_port))) {