MTK_UART_EFR_HW_FC
(~(MTK_UART_EFR_HW_FC | MTK_UART_EFR_SW_FC_MASK)));
serial_out(up, MTK_UART_EFR, MTK_UART_EFR_HW_FC |
(~(MTK_UART_EFR_HW_FC | MTK_UART_EFR_SW_FC_MASK))));
(~(MTK_UART_EFR_HW_FC | MTK_UART_EFR_SW_FC_MASK))));