samples: introduce 'with_mcuboot' sample to show sysbuild feature

This sample is intended to show users how they can create a sample which
has dedicated configuration files for extra images included in a build.

MCUboot is used as example on how its default can be adjusted and
MCUboot itself automatically be included in the build when using
sysbuild.

Signed-off-by: Torsten Rasmussen <[email protected]>

Author: tejlmand

samples/application_development/sysbuild/with_mcuboot/CMakeLists.txt

@@ -0,0 +1,13 @@
+# SPDX-License-Identifier: Apache-2.0
+
+cmake_minimum_required(VERSION 3.20.0)
+
+find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
+project(sample_with_mcuboot)
+
+# Verify that this samnple is built through sysbuild to ensure MCUboot is
+# automatically included and that sample specific MCUboot configurations are
+# used when building MCUboot.
+test_sysbuild()
+
+target_sources(app PRIVATE src/main.c)

samples/application_development/sysbuild/with_mcuboot/README.rst

@@ -0,0 +1,52 @@
+.. _with_mcuboot:
+
+Sample with MCUboot
+###################
+
+Overview
+********
+A simple example that demonstrates how building a sample using sysbuild can
+automatically include MCUboot as the bootloader.
+It showcases how the sample can adjust the configuration of extra image by
+creating a image specific Kconfig fragment.
+
+Sysbuild specific settings
+**************************
+
+This sample automatically includes MCUboot as bootloader when built using
+sysbuild.
+
+This is achieved with a sysbuild specific Kconfig configuration,
+:file:`sysbuild.conf`.
+
+The `SB_CONFIG_BOOTLOADER_MCUBOOT=y` setting in the sysbuild Kconfig file
+enables the bootloader when building with sysbuild.
+
+The :file:`sysbuild/mcuboot.conf` file will be used as an extra fragment that
+is merged together with the default configuration files used by MCUboot.
+
+:file:`sysbuild/mcuboot.conf` adjusts the log level in MCUboot, as well as
+configures MCUboot to prevent downgrades and operate in upgrade-only mode.
+
+To build both the sample and MCUboot with ``west`` for the ``reel_board``, run:
+
+.. zephyr-app-commands::
+   :tool: west
+   :app: samples/application_development/sysbuild/with_mcuboot
+   :board: reel_board
+   :goals: build
+   :west-args: --sysbuild
+   :compact:
+
+Execution output:
+
+.. code-block:: console
+
+   *** Booting Zephyr OS build v3.2.0-rc3-209-gdcf4201d3573  ***
+   *** Booting Zephyr OS build v3.2.0-rc3-209-gdcf4201d3573  ***
+   Address of sample 0xc000
+   Hello sysbuild with mcuboot! nrf52840dk_nrf52840
+
+The first ``Booting Zephyr OS build`` is printed by MCUboot itself and the
+following lines are printed by the ``with_mcuboot`` sample.
+This sample also prints its flash location.

samples/application_development/sysbuild/with_mcuboot/sample.yaml

@@ -0,0 +1,16 @@
+sample:
+    description: Sample with MCUboot built through sysbuild
+    name: with mcuboot
+tests:
+  sample.application_development.sysbuild.with_mcuboot:
+    sysbuild: True
+    # Platform allowed is used as twister using sysbuild still lacks proper
+    # filtering support, see discussion in #49552.
+    platform_allow: reel_board nrf52840dk_nrf52840
+    tags: mcuboot
+    harness: console
+    harness_config:
+      type: multi_line
+      regex:
+      - "Address of sample(.*)"
+      - "Hello sysbuild with mcuboot!(.*)"

samples/application_development/sysbuild/with_mcuboot/src/main.c

@@ -0,0 +1,14 @@
+/*
+ * Copyright (c) 2022 Nordic Semiconductor
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <zephyr/kernel.h>
+#include <zephyr/linker/linker-defs.h>
+
+void main(void)
+{
+	printk("Address of sample %p\n", (void *)__rom_region_start);
+	printk("Hello sysbuild with mcuboot! %s\n", CONFIG_BOARD);
+}

samples/application_development/sysbuild/with_mcuboot/sysbuild.conf

@@ -0,0 +1,4 @@
+# Sysbuild configuration file.
+
+# Enable MCUboot per default for this sample.
+SB_CONFIG_BOOTLOADER_MCUBOOT=y

samples/application_development/sysbuild/with_mcuboot/sysbuild/mcuboot.conf

@@ -0,0 +1,5 @@
+# Example of sample specific Kconfig changes when building sample with MCUboot
+# when using sysbuild.
+CONFIG_MCUBOOT_LOG_LEVEL_WRN=y
+CONFIG_BOOT_UPGRADE_ONLY=y
+CONFIG_MCUBOOT_DOWNGRADE_PREVENTION=y

scripts/ci/check_compliance.py

@@ -561,6 +561,8 @@ def get_defined_syms(kconf):
     "ARMCLANG_STD_LIBC",  # The ARMCLANG_STD_LIBC is defined in the toolchain
                           # Kconfig which is sourced based on Zephyr toolchain
 			  # variant and therefore not visible to compliance.
+    "BOOT_UPGRADE_ONLY", # Used in example adjusting MCUboot config, but symbol
+                         # is defined in MCUboot itself.
     "CDC_ACM_PORT_NAME_",
     "CLOCK_STM32_SYSCLK_SRC_",
     "CMU",
@@ -579,6 +581,8 @@ def get_defined_syms(kconf):
     "FOO_SETTING_1",
     "FOO_SETTING_2",
     "LSM6DSO_INT_PIN",
+    "MCUBOOT_LOG_LEVEL_WRN",        # Used in example adjusting MCUboot config,
+    "MCUBOOT_DOWNGRADE_PREVENTION", # but symbols are defined in MCUboot itself.
     "MISSING",
     "MODULES",
     "MYFEATURE",