IRQ_TX
CSR_WRITE(sc, xINTAE_SET, IRQ_RX | IRQ_TX);
if (status & (IRQ_TX | IRQ_RX)) {
CSR_WRITE(sc, xINTAE_CLR, (IRQ_TX | IRQ_RX));
CSR_WRITE(sc, xINTAE_SET, (IRQ_TX | IRQ_RX));