NXP MCXN non-TrustZone + TrustZone port

[mattia-moffa]

Tested on FRDM-MCXN947. This port uses the newer version of the MCUXpresso SDK (https://github.com/nxp-mcuxpresso/mcuxsdk-manifests).

[dgarske]

Code looks great! I'll give it a test drive on the MCX-N shortly.

[dgarske]

All testing without TrustZone works great.

Partition 1 header magic 0xFFFFFFFF invalid at 0x15000
Boot partition: 0xA000 (sz 20076, ver 0x2, type 0x601)
Partition 1 header magic 0xFFFFFFFF invalid at 0x15000
Starting Update (fallback allowed 0)
Partition 1 header magic 0xFFFFFFFF invalid at 0x15000
Boot partition: 0xA000 (sz 20076, ver 0x2, type 0x601)
Booting version: 0x2
Hello from firmware version 2

I got stuck trying to enable TrustZone. I think the MCU Configurator tool can do it and setup the memory partitions, but I don't see this documented in your PR?

[mattia-moffa]

The MCX-N doesn't need a hardware-level trustzone configuration like STM32. At reset the CPU always runs in secure mode and lets you setup secure/non-secure regions at runtime, then jump into non-secure code via the BXNS/BLXNS instructions.

The difference between mcxn.config and mcxn-tz.config is that the second one runs the app as non-secure code.

The MCU Configurator tool is more like a code generator that sets up the trustzone configuration code, it's not needed in wolfBoot (at least for now, maybe we could support it in the future).