MGE_PORT_SERIAL_CTRL
MGE_WRITE(sc, MGE_PORT_SERIAL_CTRL, reg_val);
reg_val = MGE_READ(sc, MGE_PORT_SERIAL_CTRL);
MGE_WRITE(sc, MGE_PORT_SERIAL_CTRL, reg_val);
reg_val = MGE_READ(sc, MGE_PORT_SERIAL_CTRL);
MGE_WRITE(sc, MGE_PORT_SERIAL_CTRL ,reg_val);