topic Re: IMX8MP uart2 to uart4 in i.MX Processors

IMX8MP uart2 to uart4

jmass — Thu, 16 Mar 2023 15:09:16 GMT

Hi NXP,

I'm struggling with the change of uart console port. I want to change from uart2 to uart4.
I saw that there are some questions about it and tried the answers proposed but none of them works.

https://community.nxp.com/t5/Blogs/How-to-Change-i-MX8MM-evk-Linux-Debug-UART/ba-p/1243938#M40

https://community.nxp.com/t5/i-MX-Processors/IMX8MP-EVK-Change-u-boot-debug-console-UART2-gt-UART1/m-p/1285780/highlight/true

https://community.nxp.com/t5/i-MX-Processors/i-MX8M-Plus-IMX8MP-EVK-switch-uart4-to-A53-and-change-debug/m-p/1447724#M189580

I'm using the IMX8MP-LPDDR4-EVK board only with Yocto Linux. I have done the modifications with patch files (in attachments) following others answers. I'm using the 5.15.72-2.2.0 imx manifest.

I build only the imx-image-core. It works like a charm without modifications but as I said I want to switch uart (needed in our custom board) and that kind of work but the board does not boot.

Here is what I did:
- build a clean image using imx-docker with manifest 5.15.71-2.2.0
- then create my own /sources/meta-folder with my /recipes-bsp/imx-atf & /recipes-bsp/u-boot, recipes-kernel/linux-imx
- added all config files + bbappend + files/modifs.patch
- then force compilation with bitbake imx-atf, bitbake u-boot, bitbake linux-imx

- then recreate a new *.wic.zst file with bitbake imx-image-core

everything goes well and the SDcard is flashed correctly. When I power on the board, the UART port as changed and I can see the image in attachment but the boot process stops here...

What am I missing ?

Thanks for your reply.

Re: IMX8MP uart2 to uart4

AldoG — Fri, 17 Mar 2023 20:52:33 GMT

Hello,

Most of your changes looks correct, in you Linux patch I see that you made changes to 3 device tree files so I would like to know exactly which dts are you using for your test?
is it audio board dts or jailhouse dual linux dts?

Best regards,
Aldo.

Re: IMX8MP uart2 to uart4

jmass — Mon, 20 Mar 2023 12:56:44 GMT

Hi Aldo,

Thanks for your reply,

I'm not using the audio, I basically changed most uart inside imx8mpxxx.dtb as nothing works...
Trying to just have a simple Yocto Linux booting with UART4.

Best Regards,

Re: IMX8MP uart2 to uart4

AldoG — Tue, 21 Mar 2023 23:46:02 GMT

Hi,

So you’re using the default one, correct?
Also, are you trying this on our EVK right?
I do not think that it is not booting rather is just not configured correctly.

Best regards,
Aldo.

Re: IMX8MP uart2 to uart4

jmass — Tue, 21 Mar 2023 23:49:35 GMT

Hi,

Yes I am usine the default one and yes on the NXP EVK (lpddr4).

so Am I misaine a file or something? Could it be because of the bl_31 (imx-atf) ?

thanks,

Re: IMX8MP uart2 to uart4

jmass — Thu, 23 Mar 2023 15:27:51 GMT

Hi,

Found the issue. Need to modify meta-freescale/conf/machine/include/imx-base.inc :

SOC_ATF_BOOT_UART_BASE:mx8m-generic-bsp = "0x30a60000"

and imx8mp-evk.inc :

SERIAL_CONSOLES = "115200;ttymxc3"

Thanks,