TXCSR3
reg = rt2x00mmio_register_read(rt2x00dev, TXCSR3);
rt2x00mmio_register_write(rt2x00dev, TXCSR3, reg);
reg = rt2x00mmio_register_read(rt2x00dev, TXCSR3);
rt2x00mmio_register_write(rt2x00dev, TXCSR3, reg);