i.MX8MP Changing default uart from UART2 to UART4 for u-boot console logs

[harsh1621]

I'm trying to obtain U-Boot Serial Console logs over UART4. By default, for var-som-symphony board, the stdout uart is uart2. I can obtain serial logs over uart2, but I need to change it to uart4. I'm attaching a diff file summarizing the changes I have made to get logs on uart4. For an overview the changes are:

1. include/configs/imx
   • Change CONFIG_MXC_UART_BASE to UART4_BASE_ADDR
   • Change console in environment variables to console=ttymxc3,115200\0
2. imx8mp-var-som-symphony-u-boot.dtsi:
   • Changes all instances of uart2 to uart4 /arch/arm/dts/imx8mp-var-som-symphony.dts:
   • Change stdout-path to uart4
   • Change bootargs to include ttymxc3
   • replace uart2 instances with uart4, replace the pin macros for UART2 with UART4

What more changes should I need to make?

[justincobb]

Hello,  Where you ever able to get your switch from UART2 over to UART4 to work?

Which version of uboot are you using? 

I am also developing using a imx8mp and need to switch debug ports in uboot and am using uboot-2020-10. 

I did not find the suggested blog useful. 

Thank you

[Rita_Wang]

You can see the patch modify and How to Change i.MX8MM evk Linux Debug UART.pdf

[Rita_Wang]

You can refer to https://community.nxp.com/t5/Blogs/How-to-Change-i-MX8MM-evk-Linux-Debug-UART/ba-p/1243938