debug: coredump: add internal flash backend based on nrfx

Add Zephyr core dump backend that saves a core dump to the
internal flash or RRAM partition named "coredump_partition".

This backend is an alternative to BACKEND_FLASH_PARTITION
provided by Zephyr but it bypasses Zephyr flash device layer
and uses nrfx directly, which offers the following benefits:

1. Bypasses synchronization primitives used by Zephyr flash
   or RRAM drivers. Currently, Zephyr flash drivers cannot
   be used to write to flash from a fault handler because
   of this.
2. Works with Partition Manager.
3. Minimizes the dependencies needed to successfully write
   a core dump, which is important as the core dump often
   needs to be written when the system is in the corrupted
   state.

Only flash and RRAM are supported for now (no MRAM support).

Signed-off-by: Damian Krolik <[email protected]>

Author: Damian-Nordic

CODEOWNERS

@@ -776,6 +776,7 @@
 /subsys/bootloader/                       @nrfconnect/ncs-pluto
 /subsys/caf/                              @nrfconnect/ncs-si-muffin @nrfconnect/ncs-si-bluebagel
 /subsys/debug/                            @nordic-krch
+/subsys/debug/coredump/                   @nrfconnect/ncs-protocols-serialization
 /subsys/dfu/                              @nrfconnect/ncs-pluto
 /subsys/dfu/dfu_multi_image/              @Damian-Nordic
 /subsys/dm/                               @nrfconnect/ncs-si-muffin

doc/nrf/releases_and_maturity/releases/release-notes-changelog.rst

@@ -396,7 +396,8 @@ Common Application Framework
 Debug libraries
 ---------------
 
-|no_changes_yet_note|
+* Added an experimental :ref:`Zephyr Core Dump <zephyr:coredump>` backend that writes a core dump to an internal flash or RRAM partition.
+  To enable this backend, set the :kconfig:option:`CONFIG_DEBUG_COREDUMP_BACKEND_OTHER` and :kconfig:option:`CONFIG_DEBUG_COREDUMP_BACKEND_NRF_FLASH_PARTITION` Kconfig options.
 
 DFU libraries
 -------------

subsys/debug/CMakeLists.txt

@@ -4,6 +4,7 @@
 # SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
 #
 
+add_subdirectory(coredump)
 add_subdirectory_ifdef(CONFIG_CPU_LOAD		cpu_load)
 add_subdirectory_ifdef(CONFIG_ETB_TRACE		etb_trace)
 add_subdirectory_ifdef(CONFIG_PPI_TRACE		ppi_trace)

subsys/debug/Kconfig

@@ -6,6 +6,7 @@
 
 menu "Debug"
 
+rsource "coredump/Kconfig"
 rsource "cpu_load/Kconfig"
 rsource "etb_trace/Kconfig"
 rsource "ppi_trace/Kconfig"

subsys/debug/coredump/CMakeLists.txt

@@ -0,0 +1,7 @@
+#
+# Copyright (c) 2025 Nordic Semiconductor
+#
+# SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+#
+
+zephyr_sources_ifdef(CONFIG_DEBUG_COREDUMP_BACKEND_NRF_FLASH_PARTITION coredump_backend_nrf_flash_partition.c)

subsys/debug/coredump/Kconfig

@@ -0,0 +1,25 @@
+#
+# Copyright (c) 2025 Nordic Semiconductor
+#
+# SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+#
+
+config DEBUG_COREDUMP_BACKEND_NRF_FLASH_PARTITION
+	bool "Core dump backend using nRF internal flash/RRAM partition [EXPERIMENTAL]"
+	depends on DEBUG_COREDUMP_BACKEND_OTHER
+	depends on DT_HAS_NORDIC_NRF51_FLASH_CONTROLLER_ENABLED || \
+		   DT_HAS_NORDIC_NRF52_FLASH_CONTROLLER_ENABLED || \
+		   DT_HAS_NORDIC_NRF53_FLASH_CONTROLLER_ENABLED || \
+		   DT_HAS_NORDIC_NRF91_FLASH_CONTROLLER_ENABLED || \
+		   DT_HAS_NORDIC_RRAM_CONTROLLER_ENABLED
+	depends on !BUILD_WITH_TFM
+	select FLASH_MAP
+	select EXPERIMENTAL
+	help
+	  Enables the Zephyr core dump backend that saves a core dump to the
+	  flash or RRAM partition named "coredump_partition". This backend is
+	  similar to the one enabled with DEBUG_COREDUMP_BACKEND_FLASH_PARTITION
+	  option except that it bypasses the Zephyr flash device layer and uses
+	  nrfx library directly. This minimizes the dependencies needed to write
+	  the core dump and bypasses synchronization primitives incorporated
+	  into the Zephyr flash drivers.