uart串口打印问题

hfli

我试着用USB转串口连接DEBUG，来进行串口打印。参考了Rockchip_Developer_Guide_UART_CN.pdf

1. /kernel$ git diff
   
2. diff --git a/arch/arm/boot/dts/rv1126-firefly-jd4.dtsi b/arch/arm/boot/dts/rv1126-firefly-jd4.dtsi
   
3. index f00fcb291519..de53ca662a3d 100644
   
4. --- a/arch/arm/boot/dts/rv1126-firefly-jd4.dtsi
   
5. +++ b/arch/arm/boot/dts/rv1126-firefly-jd4.dtsi
   
6. @@ -10,6 +10,7 @@
   
7. 
   
8.         chosen {
   
9.                 bootargs = "earlycon=uart8250,mmio32,0xff570000 console=ttyFIQ0 ro root=PARTLABEL=rootfs rootfstype=ext4 rootwait overlayroot=device:dev=PARTLABEL=userdata,fstype=ext4,mkfs=1 cgroup_enable=memory swapaccount=1 snd_aloop.index=7";
   
10. +               linux,stdout-path = "ttyFIQ0:1500000n8";
    
11.         };
    
12. 
    
13.         vdd_logic: vdd-logic {
    

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ttyFIQ0, 使用的是UART2:

1. 
   
2. rv1126.dtsi:
   
3.    338         fiq_debugger: fiq-debugger {
   
4.    339                 compatible = "rockchip,fiq-debugger";
   
5.    340                 rockchip,serial-id = <2>;
   
6.    341                 rockchip,wake-irq = <0>;
   
7.    342                 rockchip,irq-mode-enable = <0>;
   
8.    343                 rockchip,baudrate = <1500000>;  /* Only 115200 and 1500000 */
   
9.    344                 interrupts = <GIC_SPI 127 IRQ_TYPE_LEVEL_HIGH>;
   
10.    345                 status = "disabled";
    
11.    346         };
    
12. 
    
13. 
    
14. rv1126-firefly-rk809.dtsi
    
15. 
    
16.    646  &fiq_debugger {
    
17.    647         status = "okay";
    
18.    648 };
    
19. 
    
20. 
    

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dmesg,看到对应的串口确实enable了

1. [    0.000000] earlycon: uart8250 at MMIO32 0xff570000 (options '')
   
2. [    0.000000] bootconsole [uart8250] enabled

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通过minicom连接串口，发现串口一直没有输出。

问题可能出在哪里？

板蓝根

板子本来就设置好了 debug 串口，不需要重新配置