cmake: add ExternalNcsVariantProject_Add() function

The ExternalNcsVariantProject_Add() function will read properties from
an existing Zephyr image build and re-create the same settings in a
variant build.

Signed-off-by: Torsten Rasmussen <Torsten.Rasmussen@nordicsemi.no>

cmake/sysbuild/modules/ncs_sysbuild_extensions.cmake

@@ -0,0 +1,55 @@
+#
+# Copyright (c) 2023 Nordic Semiconductor
+#
+# SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+
+include_guard(GLOBAL)
+
+# Usage:
+# ExternalNcsVariantProject_Add(APPLICATION <name>
+# VARIANT <name>
+# )
+#
+# This function includes a variant build of an existing Zephyr based build
+# system into the multiimage build system
+#
+# APPLICATION <name>: Name of the application which is used as the source for
+# the variant build.
+# VARIANT <name>: Name of the variant build.
+function(ExternalNcsVariantProject_Add)
+ cmake_parse_arguments(VBUILD "" "APPLICATION;VARIANT" "" ${ARGN})
+
+ ExternalProject_Get_Property(${VBUILD_APPLICATION} SOURCE_DIR BINARY_DIR)
+ set(${VBUILD_APPLICATION}_BINARY_DIR ${BINARY_DIR})
+
+ ExternalZephyrProject_Add(
+ APPLICATION ${VBUILD_VARIANT}
+ SOURCE_DIR ${SOURCE_DIR}
+ BUILD_ONLY true
+ )
+
+ get_cmake_property(sysbuild_cache CACHE_VARIABLES)
+ foreach(var_name ${sysbuild_cache})
+ if("${var_name}" MATCHES "^(${}_.*)$")
+ string(LENGTH "${VBUILD_APPLICATION}" tmplen)
+ string(SUBSTRING "${var_name}" ${tmplen} -1 tmp)
+ set(${VBUILD_VARIANT}${tmp} "${${var_name}}" CACHE UNINITIALIZED "" FORCE)
+ endif()
+ endforeach()
+
+ ExternalProject_Get_Property(${VBUILD_VARIANT} BINARY_DIR)
+ ExternalProject_Add_Step(${VBUILD_VARIANT} variant_config
+ COMMAND ${CMAKE_COMMAND} -E copy_if_different
+ ${${VBUILD_APPLICATION}_BINARY_DIR}/zephyr/.config
+ ${BINARY_DIR}/zephyr/.config
+ DEPENDERS build
+ ALWAYS True
+ )
+
+ # Disable menuconfig and friends in variant builds by substitutuin with a
+ # dummy target that does nothing except returning succesfully.
+ set_property(TARGET ${VBUILD_VARIANT} APPEND PROPERTY _EP_CMAKE_ARGS
+ -DKCONFIG_TARGETS=variant_config
+ "-DEXTRA_KCONFIG_TARGET_COMMAND_FOR_variant_config=-c\;''"
+ )
+endfunction()

sysbuild/CMakeLists.txt

@@ -52,6 +52,8 @@ endfunction(${SYSBUILD_CURRENT_MODULE_NAME}_post_cmake)
 # Consider if this shoulc come through Sysbuild Kconfig flag.
 set(NCS_SYSBUILD_PARTITION_MANAGER TRUE PARENT_SCOPE)
 
+list(APPEND CMAKE_MODULE_PATH ${ZEPHYR_NRF_MODULE_DIR}/cmake/sysbuild/modules)
+include(ncs_sysbuild_extensions)
 include(${CMAKE_CURRENT_LIST_DIR}/extensions.cmake)
 
 if(SB_CONFIG_SECURE_BOOT)

sysbuild/secureboot.cmake

@@ -41,37 +41,11 @@ if(SB_CONFIG_SECURE_BOOT)
  set(image s1_image)
 
  if(SB_CONFIG_BOOTLOADER_MCUBOOT)
- set(s1_source_image mcuboot)
- set(s1_source_dir ${ZEPHYR_MCUBOOT_MODULE_DIR}/boot/zephyr/)
-
- # Set corresponding values in s1 variant of mcuboot
- set(${image}_CONFIG_BOOT_SIGNATURE_TYPE_${SB_CONFIG_SIGNATURE_TYPE} y CACHE STRING
- "MCUBOOT signature type" FORCE
- )
- set(${image}_CONFIG_BOOT_SIGNATURE_KEY_FILE
- \"${SB_CONFIG_BOOT_SIGNATURE_KEY_FILE}\" CACHE STRING
- "Signature key file for signing" FORCE
- )
+ ExternalNcsVariantProject_Add(APPLICATION mcuboot VARIANT ${image})
  else()
- set(s1_source_image ${DEFAULT_IMAGE})
- set(s1_source_dir ${APP_DIR})
+ ExternalNcsVariantProject_Add(APPLICATION ${DEFAULT_IMAGE} VARIANT ${image})
  endif()
 
- get_cmake_property(sysbuild_cache CACHE_VARIABLES)
- foreach(var_name ${sysbuild_cache})
- if("${var_name}" MATCHES "^(${s1_source_image}_.*)$")
- string(LENGTH "${s1_source_image}" tmplen)
- string(SUBSTRING "${var_name}" ${tmplen} -1 tmp)
- set(${image}${tmp} "${${var_name}}" CACHE UNINITIALIZED "" FORCE)
- endif()
- endforeach()
-
- ExternalZephyrProject_Add(
- APPLICATION ${image}
- SOURCE_DIR ${s1_source_dir}
- BUILD_ONLY true
- )
-
  set_property(GLOBAL APPEND PROPERTY
  PM_${SB_CONFIG_SECURE_BOOT_DOMAIN}_IMAGES
  "s1_image"