imx7 issues with Secure and Non-Secure boot mode

[Emanuele Ghidoli]

Hello,

I'm currently facing issues with our board, Colibri-imx7,
regarding its behavior in different boot modes:

- Secure Mode (bootm_boot_mode=sec in U-Boot):
  When running Linux in secure mode, the idle time management does not function
  properly. The following error message is displayed during boot: 
  "CPUidle arm: CPU 0 failed to init idle CPU ops".

- Non-Secure Mode (bootm_boot_mode=nonsec in U-Boot):
  In non-secure mode, the caam_jr fails to initialize correctly,
  preventing the utilization of the hardware random number generation. 
  The error message shown during boot is: 
  "caam_jr 30901000.jr: failed to flush job ring before reset".

I have conducted tests using both mainline and 6.1 stable versions,
with consistent results.

I have also reviewed the following threads for potential solutions:

 - https://lore.kernel.org/u-boot/2536787.mZni4QDSI2@crypto/
 - https://lore.kernel.org/u-boot/CAByghJZn8d91uFr5JXSR=jXcfU4engZP_=buOk7MNNjaVeigLA@mail.gmail.com/
 - https://lore.kernel.org/all/20220608170223.1536594-1-festevam@denx.de/T/

The first thread leave me thinking the only solution is to use OPTEE,
but the last email is without any answer.
So, I am considering the utilization of OPTEE, as it seems it might address 
the issues discussed in the threads.
Could this configuration potentially resolve my current issues?

Your advice would be greatly appreciated.

Kind regards,

Emanuele Ghidoli