UART¶

Firefly_RK3399¶

开发板默认使用uart2作为调试串口,在bootargs中有如下设置

bootargs = "earlycon=uart8250,mmio32,0xff1a0000";

其中0xff1a0000就是uart2的地址

uart2: serial@ff1a0000

在cmdline中设置了console使用节点ttyFIQ0(等价与ttyS2)

androidboot.console=ttyFIQ0

ttyFIQ0节点驱动对应的dts如下

fiq_debugger: fiq-debugger {
    compatible = "rockchip,fiq-debugger";
    rockchip,serial-id = <2>;
    rockchip,signal-irq = <182>;
    rockchip,wake-irq = <0>;
    rockchip,irq-mode-enable = <1>;  /* If enable uart uses irq instead of fiq */
    rockchip,baudrate = <115200>;  /* Only 115200 and 1500000 */
    pinctrl-names = "default";
    pinctrl-0 = <&uart2c_xfer>;
};

其中设置了对应的串口为uart2

rockchip,serial-id = <2>;

所以如果要将调试串口改成其它串口,比如uart4

只需要fiq的dts和bootargs,内核日志就将在uart4上输出

rockchip,serial-id = <4>;
pinctrl-0 = <&uart4_xfer>;
bootargs = "earlycon=uart8250,mmio32,ff370000";