zephyr: Add estimated image footer size to cache in sysbuild

Adds MCUboot's estimated overhead footer size to the application's cache when using sysbuild, this allows that information to be propagated to applications which can use the information to reduce the available size for an application, preventing the MCUboot error of image too large to swap. Signed-off-by: Jamie McCrae <[email protected]>
mcu-tools · Nov 1, 2023 · 74c86a8 · 74c86a8
1 parent 304fd41
commit 74c86a8
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diff --git a/boot/zephyr/CMakeLists.txt b/boot/zephyr/CMakeLists.txt
@@ -1,6 +1,7 @@
 # CMakeLists.txt for building mcuboot as a Zephyr project
 #
 # Copyright (c) 2017 Open Source Foundries Limited
+# Copyright (c) 2023 Nordic Semiconductor ASA
 #
 # SPDX-License-Identifier: Apache-2.0
 
@@ -370,3 +371,131 @@ zephyr_library_sources(
   ${BOOT_DIR}/zephyr/arm_cleanup.c
 )
 endif()
+
+if(SYSBUILD)
+  function(align_up num align result)
+    math(EXPR out "(((${num}) + ((${align}) - 1)) & ~((${align}) - 1))")
+    set(${result} "${out}" PARENT_SCOPE)
+  endfunction()
+
+  function(dt_get_parent node)
+    string(FIND "${${node}}" "/" pos REVERSE)
+
+    if(pos EQUAL -1)
+      message(ERROR "Unable to get parent of node: ${${node}}")
+    endif()
+
+    string(SUBSTRING "${${node}}" 0 ${pos} ${node})
+    set(${node} "${${node}}" PARENT_SCOPE)
+  endfunction()
+
+  if(CONFIG_BOOT_SWAP_USING_SCRATCH OR CONFIG_BOOT_SWAP_USING_MOVE OR CONFIG_BOOT_UPGRADE_ONLY OR CONFIG_BOOT_DIRECT_XIP OR CONFIG_BOOT_RAM_LOAD)
+    # TODO: RAM LOAD support
+    dt_nodelabel(slot0_flash NODELABEL "slot0_partition")
+    dt_get_parent(slot0_flash)
+    dt_get_parent(slot0_flash)
+
+    if(NOT CONFIG_SINGLE_APPLICATION_SLOT)
+      dt_nodelabel(slot1_flash NODELABEL "slot1_partition")
+      dt_get_parent(slot1_flash)
+      dt_get_parent(slot1_flash)
+
+      if(NOT "${slot0_flash}" STREQUAL "${slot1_flash}")
+        # Check both slots for the one with the largest write/erase block size
+        dt_prop(erase_size_slot0 PATH "${slot0_flash}" PROPERTY "erase-block-size")
+        dt_prop(write_size_slot0 PATH "${slot0_flash}" PROPERTY "write-block-size")
+        dt_prop(erase_size_slot1 PATH "${slot1_flash}" PROPERTY "erase-block-size")
+        dt_prop(write_size_slot1 PATH "${slot1_flash}" PROPERTY "write-block-size")
+
+        if(${erase_size_slot0} GREATER ${erase_size_slot1})
+          set(erase_size ${erase_size_slot0})
+        else()
+          set(erase_size ${erase_size_slot1})
+        endif()
+
+        if(${write_size_slot0} GREATER ${write_size_slot1})
+          set(write_size ${write_size_slot0})
+        else()
+          set(write_size ${write_size_slot1})
+        endif()
+      else()
+        dt_prop(erase_size PATH "${slot0_flash}" PROPERTY "erase-block-size")
+        dt_prop(write_size PATH "${slot0_flash}" PROPERTY "write-block-size")
+      endif()
+
+    else()
+      dt_prop(erase_size PATH "${slot0_flash}" PROPERTY "erase-block-size")
+      dt_prop(write_size PATH "${slot0_flash}" PROPERTY "write-block-size")
+    endif()
+
+    if(write_size LESS 8)
+      set(write_size 8)
+    endif()
+
+    set(key_size 0)
+
+    # Boot trailer magic size
+    set(boot_magic_size 16)
+
+    # Estimates for trailer TLV data size, this was taken from hello world builds for nrf52840dk
+    if(CONFIG_BOOT_SIGNATURE_TYPE_RSA)
+      if(CONFIG_BOOT_SIGNATURE_TYPE_RSA_LEN EQUAL 3072)
+        set(boot_tlv_estimate 464)
+      else()
+        set(boot_tlv_estimate 336)
+      endif()
+    elseif(CONFIG_BOOT_SIGNATURE_TYPE_ECDSA_P256)
+      set(boot_tlv_estimate 150)
+    elseif(CONFIG_BOOT_SIGNATURE_TYPE_ED25519)
+      set(boot_tlv_estimate 144)
+    else()
+      set(boot_tlv_estimate 40)
+    endif()
+
+    if(CONFIG_BOOT_ENCRYPT_RSA OR CONFIG_BOOT_ENCRYPT_EC256 OR CONFIG_BOOT_ENCRYPT_X25519)
+      # 128-bit AES key size
+      set(boot_enc_key_size 16)
+
+      if(CONFIG_BOOT_SWAP_SAVE_ENCTLV)
+        if(CONFIG_BOOT_ENCRYPT_RSA)
+          set(key_size 256)
+        elseif(CONFIG_BOOT_ENCRYPT_EC256)
+          math(EXPR key_size "65 + 32 + ${boot_enc_key_size}")
+        elseif(CONFIG_BOOT_ENCRYPT_X25519)
+          math(EXPR key_size "32 + 32 + ${boot_enc_key_size}")
+        endif()
+      else()
+        set(key_size "${boot_enc_key_size}")
+      endif()
+
+      align_up(${key_size} ${write_size} key_size)
+      math(EXPR key_size "${key_size} * 2")
+    endif()
+
+    align_up(${boot_magic_size} ${write_size} boot_magic_size)
+
+    if(CONFIG_SINGLE_APPLICATION_SLOT)
+      set(boot_swap_data_size 0)
+    else()
+      math(EXPR boot_swap_data_size "${write_size} * 4")
+    endif()
+
+    if(CONFIG_BOOT_SWAP_USING_SCRATCH OR CONFIG_BOOT_SWAP_USING_MOVE)
+      math(EXPR boot_status_data_size "${CONFIG_BOOT_MAX_IMG_SECTORS} * (3 * ${write_size})")
+    else()
+      set(boot_status_data_size 0)
+    endif()
+
+    math(EXPR required_size "${key_size} + ${boot_magic_size} + ${boot_swap_data_size} + ${boot_status_data_size} + ${boot_tlv_estimate}")
+
+    align_up(${required_size} ${erase_size} required_size)
+
+    if(CONFIG_BOOT_SWAP_USING_MOVE)
+      math(EXPR required_size "${required_size} + ${erase_size}")
+    endif()
+  else()
+    set(required_size 0)
+  endif()
+
+  set(mcuboot_image_footer_size ${required_size} CACHE INTERNAL "Estimated MCUboot image trailer size" FORCE)
+endif()
diff --git a/boot/zephyr/sysbuild/CMakeLists.txt b/boot/zephyr/sysbuild/CMakeLists.txt
@@ -0,0 +1,40 @@
+function(mathup num align result)
+  math(EXPR out "(((${num}) + ((${align}) - 1)) & ~((${align}) - 1))")
+  set(${result} "${out}" PARENT_SCOPE)
+endfunction()
+
+function(${SYSBUILD_CURRENT_MODULE_NAME}_pre_image_cmake)
+  cmake_parse_arguments(POST_IMAGE_CMAKE "" "IMAGE" "IMAGES" ${ARGN})
+
+  if(NOT "${POST_IMAGE_CMAKE_IMAGE}" STREQUAL "mcuboot")
+    return()
+  endif()
+
+  set_property(
+    DIRECTORY APPEND PROPERTY
+    CMAKE_CONFIGURE_DEPENDS
+    ${CMAKE_BINARY_DIR}/mcuboot/CMakeCache.txt
+    ${CMAKE_BINARY_DIR}/mcuboot/zephyr/.config
+    )
+endfunction(${SYSBUILD_CURRENT_MODULE_NAME}_pre_image_cmake)
+
+function(${SYSBUILD_CURRENT_MODULE_NAME}_post_image_cmake)
+  cmake_parse_arguments(POST_IMAGE_CMAKE "" "IMAGE" "IMAGES" ${ARGN})
+
+  if(NOT "${POST_IMAGE_CMAKE_IMAGE}" STREQUAL "mcuboot")
+    return()
+  endif()
+
+  foreach(image ${IMAGES})
+    set(app_type)
+    get_property(app_type TARGET ${image} PROPERTY APP_TYPE)
+
+    if("${app_type}" STREQUAL "MAIN")
+      sysbuild_get(mcuboot_image_footer_size IMAGE mcuboot CACHE)
+      math(EXPR mcuboot_image_footer_size "${mcuboot_image_footer_size}" OUTPUT_FORMAT HEXADECIMAL)
+
+      set_property(TARGET ${image} APPEND_STRING PROPERTY CONFIG "CONFIG_ROM_END_OFFSET=${mcuboot_image_footer_size}\n")
+      return()
+    endif()
+  endforeach()
+endfunction(${SYSBUILD_CURRENT_MODULE_NAME}_post_image_cmake)
diff --git a/zephyr/module.yml b/zephyr/module.yml
@@ -2,3 +2,4 @@ samples:
   - boot/zephyr
 build:
   cmake: ./boot/bootutil/zephyr
+  sysbuild-cmake: boot/zephyr/sysbuild