FEDEVEL
Platform forum

arkanoid , 07-04-2018, 12:21 PM

I'm in your course of Linux embedded and I've some doubts about configuration between uboot and linux. For example

• If you configure the LCD to works well in U-boot. Do you have to configure in the same way in the Kernel? The same for Ethernet, etc??
• You calibrate the memories for the u-boot. Do you have to place those values in the kernel too?

Thanks!

robertferanec , 07-07-2018, 02:08 AM

Normally we only configure bare minimum in uBoot and then reconfigure everything properly in Linux (bare minimum = we only configure in uBoot the pins and interfaces needed to boot up Linux). When booting Linux, I would not rely on using settings from uBoot - Linux should reconfigure everything even if uBoot set it before.

PS: Memories are set in uBoot, I have never seen Linux changing memory settings (I am not sure if Linux can change them, could be dangerous). Calibration is done for specific PCB layout, it is not done for uBoot or Linux. uBoot just sets the memory controller based on the values measured during calibration.

PSS: Some interfaces may reset when Linux is booting (e.g. Ethernet), so you definitely may need to configure them again.