BMAC_BUFLEN
sc->sc_rxbuf = sc->sc_txbuf + BMAC_BUFLEN * BMAC_TXBUFS;
sc->sc_rxbuf_pa = sc->sc_txbuf_pa + BMAC_BUFLEN * BMAC_TXBUFS;
DBDMA_BUILD(cmd, DBDMA_CMD_IN_LAST, 0, BMAC_BUFLEN,
sc->sc_rxbuf_pa + BMAC_BUFLEN * i,
data = sc->sc_rxbuf + BMAC_BUFLEN * i;
#define BMAC_BUFSZ ((BMAC_RXBUFS + BMAC_TXBUFS + 2) * BMAC_BUFLEN)