WPDMA_GLO_CFG_TX_WRITEBACK_DONE
rt2x00_set_field32(®, WPDMA_GLO_CFG_TX_WRITEBACK_DONE, 1);
rt2x00_set_field32(®, WPDMA_GLO_CFG_TX_WRITEBACK_DONE, 1);
rt2x00_set_field32(®, WPDMA_GLO_CFG_TX_WRITEBACK_DONE, 0);