Hi all.
Worked with imx-linux-kirkstone (kernel 5.15.52) with the HW imx8mm_evk_lpddr4 long enough, with different hardware configurations (different SDRAMs, network devices, etc.). All worked, in any case the problems were quite understandable.
Now I switched to imx-linux-langdale (kernel 6.1.1) with the same HW and imx8mm_evk_lpddr4. And immediately got one of the most difficult problems to debug.
So:
- U-Boot, although formally has the same version, but contains a number of significant changes. However, it starts normally and boots a previous customized Linux kernel 5.15.52 without problems.
- Linux kernel 6.1.1 is built without any changes in the configuration and source code
- When trying to load it on the serial console the last (normal) message from U-Boot is visible:
Starting kernel ...
then nothing happens.
This means that the kernel crashes before it initializes the serial console.
Requests:
- some idea.
- maybe someone has a tested fragment of assembly language text for the A53 output the symbol to the console serial port. The idea is: (a) to put this fragment into the entry.S before the virtual memory is initialized (and after is also possible); (b) U_Boot leaves the serial port hardware in an initialized state so I can determine if the kernel starts at all and approximately where it crashes.
Thank you.
