Extend samples/zephyr_exteral_config with keys

Extended build file with logic copied from boot/zephyr/CMakeLists.txt
to pull in keys.c **from that directory**.

The build `west build -p always -b nrf52840dk_nrf52840
mcuboot/samples/zephyr_external_config` now succeeds, but is
about 5000 bytes larger than the original.  Inspection of the
differences shows NORDIC_QSPI_NOR is enabled here and disabled in the
original (through a local board-specific config).

Signed-off-by: Gregory SHUE <[email protected]>

Author: legrand-gregshue

samples/zephyr_external_config/CMakeLists.txt

@@ -1,9 +1,89 @@
+# CMakeLists.txt for building mcuboot as a Zephyr project
+#
+# Copyright (c) 2017 Open Source Foundries Limited
 # Copyright (c) 2022 Legrand North America, LLC.
+#
 # SPDX-License-Identifier: Apache-2.0
 
-cmake_minimum_required(VERSION 3.20.0)
+cmake_minimum_required(VERSION 3.13.1)
 
+# Add a common dts overlay necessary to ensure mcuboot is linked into,
+# and fits inside, the boot partition. (If the user specified a
+# DTC_OVERLAY_FILE on the CMake command line, we need to append onto
+# the list).
+if(DTC_OVERLAY_FILE)
+  set(DTC_OVERLAY_FILE
+	"${DTC_OVERLAY_FILE} ../../boot/zephyr/dts.overlay"
+    CACHE STRING "" FORCE
+    )
+else()
+  set(DTC_OVERLAY_FILE ../../boot/zephyr/dts.overlay)
+endif()
+
+# Enable Zephyr runner options which request mass erase if so
+# configured.
+#
+# Note that this also disables the default "leave" option when
+# targeting STM32 DfuSe devices with dfu-util, making the chip stay in
+# the bootloader after flashing.
+#
+# That's the right thing, because mcuboot has nothing to do since the
+# chip was just erased. The next thing the user is going to want to do
+# is flash the application. (Developers can reset DfuSE devices
+# manually to test mcuboot behavior on an otherwise erased flash
+# device.)
+macro(app_set_runner_args)
+  if(CONFIG_ZEPHYR_TRY_MASS_ERASE)
+    board_runner_args(dfu-util "--dfuse-modifiers=force:mass-erase")
+    board_runner_args(pyocd "--flash-opt=-e=chip")
+    board_runner_args(nrfjprog "--erase")
+  endif()
+endmacro()
+
+# find_package(Zephyr) in order to load application boilerplate:
+# http://docs.zephyrproject.org/application/application.html
 find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
 project(mcuboot_exernal_config)
 
-target_sources(app PRIVATE empty.c)
+target_sources(app PRIVATE
+  ${ZEPHYR_MCUBOOT_MODULE_DIR}/boot/zephyr/keys.c
+  )
+
+if(NOT CONFIG_BOOT_SIGNATURE_KEY_FILE STREQUAL "")
+  # CONF_FILE points to the KConfig configuration files of the bootloader.
+  foreach (filepath ${CONF_FILE})
+    file(READ ${filepath} temp_text)
+    string(FIND "${temp_text}" ${CONFIG_BOOT_SIGNATURE_KEY_FILE} match)
+    if (${match} GREATER_EQUAL 0)
+      if (NOT DEFINED CONF_DIR)
+        get_filename_component(CONF_DIR ${filepath} DIRECTORY)
+      else()
+        message(FATAL_ERROR "Signature key file defined in multiple conf files")
+      endif()
+    endif()
+  endforeach()
+
+  if(IS_ABSOLUTE ${CONFIG_BOOT_SIGNATURE_KEY_FILE})
+    set(KEY_FILE ${CONFIG_BOOT_SIGNATURE_KEY_FILE})
+  elseif((DEFINED CONF_DIR) AND
+	 (EXISTS ${CONF_DIR}/${CONFIG_BOOT_SIGNATURE_KEY_FILE}))
+    set(KEY_FILE ${CONF_DIR}/${CONFIG_BOOT_SIGNATURE_KEY_FILE})
+  else()
+    set(KEY_FILE ${ZEPHYR_MCUBOOT_MODULE_DIR}/${CONFIG_BOOT_SIGNATURE_KEY_FILE})
+  endif()
+  message("MCUBoot bootloader key file: ${KEY_FILE}")
+
+  set(GENERATED_PUBKEY ${ZEPHYR_BINARY_DIR}/autogen-pubkey.c)
+  add_custom_command(
+    OUTPUT ${GENERATED_PUBKEY}
+    COMMAND
+    ${PYTHON_EXECUTABLE}
+    ${ZEPHYR_MCUBOOT_MODULE_DIR}/scripts/imgtool.py
+    getpub
+    -k
+    ${KEY_FILE}
+    > ${GENERATED_PUBKEY}
+    DEPENDS ${KEY_FILE}
+    )
+  zephyr_library_sources(${GENERATED_PUBKEY})
+endif()