AR9003_NTXSTATUS
sc->sc_txscur = (sc->sc_txscur + 1) % AR9003_NTXSTATUS;
size = AR9003_NTXSTATUS * sizeof(struct ar_tx_status);
AR9003_NTXSTATUS * sizeof(struct ar_tx_status));
memset(sc->sc_txsring, 0, AR9003_NTXSTATUS * sizeof(struct ar_tx_status));