How to Change console serial port before making an image

[jonasnyberg]

Hi all,

I'm quite new to building my own linux images with Yocto and has come so far to almost boot my custom image.

I'm using the Argon i.mx6ul board which have it's serial output on Uart 3 instead of what it seems to be a default of Uart 1 when building an image from scratch.

I've tried to change the line "mxc0:12345:respawn:/sbin/getty -L 115200 ttymc0" in the "inittab" file in my build/tmp/work folder to mxc2, ttymc2 and force a rebuild, but with no success. I can see that the .sdcard file is rebuilt but when I look at the contents in the associated tar-archive I see no change. Still the default mxc0.

Can somebody help me on how to change this so that it will be included in the builds (preferable permanent change)?

I have had a look at the meta-bsp/recipes-core/sysvinit/sysvinit_2.88dsf.bbappend file, where I see a SERIAL_CONSOLES variable etc. but can't find where it is defined and how to change it?

I've also tried to add a SERIAL_CONSOLE line with ttymc2 to my Machine file but with no success.

Are there any other conf files for the sysvinit-inittab recipe?

I'm stuck now when booting my device at some point saying applying local.conf something... and after that it says
INIT: Id "mxc0" respawning too fast: disabled for 5 minutes, in an infinite loop.

I can see all the text up to that point in the terminal after telling u-boot to boot my image.

Thanks in advance,

Jonas

[igorpadykov]

Hi Jonas

one can look at example of i.MX6 Sabre AI board, in uboot/include/configs/mx6qsabreauto.h:

#define CONFIG_MXC_UART_BASE    UART4_BASE

#define CONFIG_CONSOLE_DEV        "ttymxc3"

Also please refer to attached Linux Guide p.25 "Specifying the console".

Best regards
igor
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[jonasnyberg]

Hi Igor,

Thanks very much for your answer.

I got it to work the dirty way first by manually editing the "echo" line that writes the ttmxc0 line in the sysvinit_2.88dsf.bb file.

After that, rebuilding the image and now my board boots as it should.

I know that this isn't a nice solution but since I couldn't find any clear solution where to define the variable "ttmxc*".

Also I couldn't find any .h files for my board, or any other board in the yocto directories. 

Thanks again for your input.

Jonas