Support for NXP S32K14XX

[dgarske]

Add NXP S32K1xx (S32K142/144/146/148) Support

Summary

This PR adds complete bare-metal wolfBoot support for the NXP S32K1xx family of automotive-grade Cortex-M4F microcontrollers. The implementation has been tested on the S32K142 and includes support for all variants (S32K142, S32K144, S32K146, S32K148).

Features

• Bare-metal HAL implementation - No SDK required, fully self-contained
• Flash programming support with 8-byte phrase programming and sector erase
• FCF (Flash Configuration Field) protection - Prevents accidental device locking by refusing writes to the 0x400-0x40F region
• Watchdog management - Proper disable during boot, optional re-enable before jumping to application
• LPUART debug output on LPUART1 (PTC6=RX, PTC7=TX) at 115200 baud
• Clock configuration using FIRC (48 MHz internal RC oscillator) - no external crystal required
• Variant-aware flash sector sizing - 2KB sectors for S32K142 (256KB), 4KB sectors for larger variants

Configuration Options

Option	Description
WOLFBOOT_RESTORE_CLOCK	Restore clock to SIRC (8 MHz) before booting application
WOLFBOOT_DISABLE_WATCHDOG_ON_BOOT	Keep watchdog disabled when jumping to application
WATCHDOG / WATCHDOG_TIMEOUT_MS	Enable watchdog during wolfBoot operation
DEBUG_UART	Enable LPUART1 debug output
S32K144, S32K146, S32K148	Select variant (default is S32K142)

Memory Layout (S32K142 - 256KB Flash)

Region	Address Range	Size
Bootloader	0x00000000 - 0x0000BFFF	48 KB
Boot Partition	0x0000C000 - 0x00024FFF	100 KB
Update Partition	0x00025000 - 0x0003DFFF	100 KB
Swap Sector	0x0003E000 - 0x0003E7FF	2 KB

Changes

• New HAL: hal/s32k1xx.c and hal/s32k1xx.h with register definitions and flash/clock/UART drivers
• New linker scripts: hal/s32k1xx.ld (bootloader) and test-app/ARM-s32k1xx.ld (application)
• Configuration examples for all variants:
  • config/examples/nxp-s32k142.config
  • config/examples/nxp-s32k144.config
  • config/examples/nxp-s32k146.config
  • config/examples/nxp-s32k148.config
• Test application: test-app/app_s32k1xx.c with LED blink and wolfBoot API usage
• Build system updates in arch.mk and test-app/Makefile
• CI workflow updates to test all S32K1xx configurations
• Comprehensive documentation in docs/Targets.md including:
  • Build instructions
  • Programming/debugging with PEMicro, J-Link, and OpenSDA
  • Device recovery procedures for locked devices
  • Clock configuration details
• VS Code integration with PEMicro GDB server launch configurations

Testing

• Tested on S32K142 EVB board with:
  • Flash erase and program operations
  • Boot partition verification
  • Application handoff
  • UART debug output
  • Watchdog functionality

Future Work

• SPLL + SOSC support for true 112 MHz HSRUN mode operation
• CSEc hardware crypto acceleration integration
• FlexNVM/EEPROM support
• CAN/LIN bootloader for automotive update scenarios