AGE_TX_RING_SZ
bzero(rd->age_tx_ring, AGE_TX_RING_SZ);
tx_ring_end = sc->age_rdata.age_tx_ring_paddr + AGE_TX_RING_SZ;
AGE_TX_RING_SZ, /* maxsize */
AGE_TX_RING_SZ, /* maxsegsize */
AGE_TX_RING_SZ, age_dmamap_cb, &ctx, 0);