Bluetooth: Mesh: add tc to psa key convertor

Commit adds functionality that reads the stored tinycrypt
keys from settings and import them as persistent keys
into PSA crypto library.

Signed-off-by: Aleksandr Khromykh <aleksandr.khromykh@nordicsemi.no>

Author: alxelax

subsys/bluetooth/mesh/CMakeLists.txt

@@ -81,6 +81,8 @@ zephyr_linker_sources(SECTIONS scene_types.ld)
 
 zephyr_library_sources_ifdef(CONFIG_BT_MESH_RPL_STORAGE_MODE_EMDS rpl.c)
 
+zephyr_library_sources_ifdef(CONFIG_BT_MESH_KEY_IMPORTER key_importer.c)
+
 if(CONFIG_BT_MESH_USES_MBEDTLS_PSA AND (NOT CONFIG_SOC_FAMILY_NORDIC_NRF))
   zephyr_library_link_libraries(mbedTLS)
 endif()

subsys/bluetooth/mesh/Kconfig

@@ -167,6 +167,14 @@ config BT_MESH_USES_TFM_PSA
 	select PSA_WANT_KEY_TYPE_ECC_KEY_PAIR_IMPORT
 	select PSA_WANT_KEY_TYPE_ECC_KEY_PAIR_EXPORT
 
+config BT_MESH_KEY_IMPORTER
+	bool "Use key importer"
+	help
+	  Use key importer to read out the keys stored in settings subsystem
+	  and import them into PSA internal trusted storage. This is required if
+	  a provisioned device is still going to stay provisioned after changing
+	  from an image using TinyCrypt to an image that uses PSA crypto.
+
 choice TFM_PROFILE_TYPE
 	depends on BT_MESH_USES_TFM_PSA
 	default TFM_PROFILE_TYPE_NOT_SET