BMAC_BUFSZ
error = bus_dmamem_alloc(sc->sc_dmat, BMAC_BUFSZ,
BMAC_BUFSZ, &sc->sc_txbuf, BUS_DMA_NOWAIT);
error = bus_dmamap_create(sc->sc_dmat, BMAC_BUFSZ, 1, BMAC_BUFSZ, 0,
bus_dmamem_unmap(sc->sc_dmat, sc->sc_txbuf, BMAC_BUFSZ);
BMAC_BUFSZ, NULL, BUS_DMA_NOWAIT);
bus_dmamem_unmap(sc->sc_dmat, sc->sc_txbuf, BMAC_BUFSZ);