RK3568调试串口

RK3568的调试串口默认为uart2。fiq debugger是集成到内核中的一种系统调试手段。

驱动代码 kernel/drivers/soc/rockchip/rk_fiq_debugger.c

要使用fiq debugger，需要内核配置：

CONFIG_FIQ_DEBUGGER
CONFIG_FIQ_DEBUGGER_CONSOLE
CONFIG_FIQ_DEBUGGER_CONSOLE_DEFAULT_ENABLE

fiq和普通串口是互斥的，所以配置为fiq后，默认的uart2就需要被禁用。

fiq-debugger {
	compatible = "rockchip,fiq-debugger";
	rockchip,serial-id = <2>;
	rockchip,wake-irq = <0>;
	/* If enable uart uses irq instead of fiq */
	rockchip,irq-mode-enable = <1>;
	rockchip,baudrate = <115200>;  /* Only 115200 and 1500000 */
	interrupts = <GIC_SPI 252 IRQ_TYPE_LEVEL_LOW>;
	pinctrl-names = "default";
	pinctrl-0 = <&uart2m0_xfer>;
	status = "okay";
};

&uart2 {
	status = "disabled";
	pinctrl-names = "default";
	pinctrl-0 = <&uart2m0_xfer>;
};
 
/ {
	chosen: chosen {
		bootargs = "earlycon=uart8250,mmio32,0xfe660000 console=ttyFIQ0 root=PARTUUID=614e0000-0000 rw rootwait";
	};
};