bootloader: force multi image mcuboot when b0 enabled

To support updateable mcuboot, mcuboot needs to be built with multi
image support. Force this configuration when b0 is enabled.

Signed-off-by: Håkon Øye Amundsen <[email protected]>

Author: hakonfam

subsys/bootloader/image/CMakeLists.txt

@@ -4,6 +4,16 @@
 # SPDX-License-Identifier: LicenseRef-BSD-5-Clause-Nordic
 #
 
+function(add_overlay_config image overlay_file)
+  set(old_conf ${${image}OVERLAY_CONFIG})
+  string(FIND "${old_conf}" "${overlay_file}" found)
+  if (${found} EQUAL -1)
+    set(${image}OVERLAY_CONFIG
+      "${old_conf} ${overlay_file}"
+      CACHE STRING "" FORCE)
+  endif()
+endfunction()
+
 # This CMakeLists.txt is executed by the root application only when
 # B0 (SECURE_BOOT) is enabled. First, figure out what image will be
 # booted by B0, and set the required properties for that image to be
@@ -12,6 +22,11 @@
 if (CONFIG_BOOTLOADER_MCUBOOT)
   set(image_to_boot mcuboot_)
 
+  add_overlay_config(
+    mcuboot_
+    ${CMAKE_CURRENT_SOURCE_DIR}/multi_image_mcuboot.conf
+    )
+
   # Partition S1 is only enabled when MCUBoot is enabled.
   set(s1_addr $<TARGET_PROPERTY:partition_manager,PM_S1_ADDRESS>)
 
@@ -27,14 +42,15 @@ but MCUboot is not being built.")
   endif()
 endif()
 
-# Include a kconfig file which enables CONFIG_FW_INFO in the image
-# which is booted by B0.
-set(old_conf ${${image_to_boot}OVERLAY_CONFIG})
-string(FIND "${old_conf}" "${CMAKE_CURRENT_SOURCE_DIR}/fw_info.conf" found)
-if (${found} EQUAL -1)
-  set(${image_to_boot}OVERLAY_CONFIG
-    "${old_conf} ${CMAKE_CURRENT_SOURCE_DIR}/fw_info.conf"
-    CACHE STRING "" FORCE)
+if (image_to_boot)
+  # Include a kconfig file which enables CONFIG_FW_INFO in the image
+  # which is booted by B0.
+  add_overlay_config(
+    ${image_to_boot}
+    ${CMAKE_CURRENT_SOURCE_DIR}/fw_info.conf
+    )
+else()
+  assert(CONFIG_FW_INFO "CONFIG_FW_INFO must be set")
 endif()
 
 # Partition S0 will always contain the image to be booted by B0.

subsys/bootloader/image/multi_image_mcuboot.conf

@@ -0,0 +1 @@
+CONFIG_UPDATEABLE_IMAGE_NUMBER=2