bootloader: Kconfig files in bootloader_components is now part of menuconfig

It is now possible to configure the options (Kconfig) of bootloader components
directly from the menuconfig

examples/custom_bootloader/bootloader_override/bootloader_components/main/Kconfig

@@ -0,0 +1,8 @@
+menu "Bootloader welcome message"
+
+    config EXAMPLE_BOOTLOADER_WELCOME_MESSAGE
+        string "Bootloader welcome message"
+        default "Custom bootloader message defined in the KConfig file."
+        help
+            Message to print by the custom bootloader when booting up.
+endmenu

examples/custom_bootloader/bootloader_override/bootloader_components/main/bootloader_start.c

@@ -4,6 +4,7 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 #include <stdbool.h>
+#include "sdkconfig.h"
 #include "esp_log.h"
 #include "bootloader_init.h"
 #include "bootloader_utility.h"
@@ -41,7 +42,7 @@ void __attribute__((noreturn)) call_start_cpu0(void)
     }
 
     // 2.1 Print a custom message!
-    esp_rom_printf("[%s] Custom bootloader has been initialized correctly.\n", TAG);
+    esp_rom_printf("[%s] %s\n", TAG, CONFIG_EXAMPLE_BOOTLOADER_WELCOME_MESSAGE);
 
     // 3. Load the app image for booting
     bootloader_utility_load_boot_image(&bs, boot_index);

examples/custom_bootloader/bootloader_override/example_test.py

@@ -10,7 +10,10 @@ def test_custom_bootloader_impl_example(env, _):  # type: ignore
     dut.start_app()
 
     # Expect to read a message from the custom bootloader
-    dut.expect('Custom bootloader has been initialized correctly.')
+    # This message is defined in the Kconfig file, retrieve it while deleting
+    # leading and trailing quotes (")
+    welcome_message = dut.app.get_sdkconfig()['CONFIG_EXAMPLE_BOOTLOADER_WELCOME_MESSAGE'].strip("\"")
+    dut.expect(welcome_message)
 
     # Expect to read a message from the user application
     dut.expect('Application started!')

tools/cmake/kconfig.cmake

@@ -112,6 +112,29 @@ function(__kconfig_component_init component_target)
     __component_set_property(${component_target} SDKCONFIG_RENAME "${sdkconfig_rename}")
 endfunction()
 
+#
+# Add bootloader components Kconfig and Kconfig.projbuild files to BOOTLOADER_KCONFIG
+# and BOOTLOADER_KCONFIGS_PROJ properties respectively.
+#
+function(__kconfig_bootloader_component_add component_dir)
+    idf_build_get_property(bootloader_kconfigs BOOTLOADER_KCONFIGS)
+    idf_build_get_property(bootloader_kconfigs_proj BOOTLOADER_KCONFIGS_PROJ)
+
+    file(GLOB kconfig "${component_dir}/Kconfig")
+    if(EXISTS "${kconfig}" AND NOT IS_DIRECTORY "${kconfig}")
+        list(APPEND bootloader_kconfigs "${kconfig}")
+    endif()
+
+    file(GLOB kconfig "${component_dir}/Kconfig.projbuild")
+    if(EXISTS "${kconfig}" AND NOT IS_DIRECTORY "${kconfig}")
+        list(APPEND bootloader_kconfigs_proj "${kconfig}")
+    endif()
+
+    idf_build_set_property(BOOTLOADER_KCONFIGS "${bootloader_kconfigs}")
+    idf_build_set_property(BOOTLOADER_KCONFIGS_PROJ "${bootloader_kconfigs_proj}")
+endfunction()
+
+
 #
 # Generate the config files and create config related targets and configure
 # dependencies.
@@ -137,6 +160,12 @@ function(__kconfig_generate_config sdkconfig sdkconfig_defaults)
         endif()
     endforeach()
 
+    # Take into account bootloader components configuration files
+    idf_build_get_property(bootloader_kconfigs BOOTLOADER_KCONFIGS)
+    idf_build_get_property(bootloader_kconfigs_proj BOOTLOADER_KCONFIGS_PROJ)
+    list(APPEND kconfigs "${bootloader_kconfigs}")
+    list(APPEND kconfig_projbuilds "${bootloader_kconfigs_proj}")
+
     # Store the list version of kconfigs and kconfig_projbuilds
     idf_build_set_property(KCONFIGS "${kconfigs}")
     idf_build_set_property(KCONFIG_PROJBUILDS "${kconfig_projbuilds}")

tools/cmake/project.cmake

@@ -197,6 +197,20 @@ function(__project_init components_var test_components_var)
         __project_component_dir("${CMAKE_CURRENT_LIST_DIR}/components")
     endif()
 
+    # For bootloader components, we only need to set-up the Kconfig files.
+    # Indeed, bootloader is currently compiled as a subproject, thus,
+    # its components are not part of the main project.
+    # However, in order to be able to configure these bootloader components
+    # using menuconfig, we need to look for their Kconfig-related files now.
+    file(GLOB bootloader_component_dirs "${CMAKE_CURRENT_LIST_DIR}/bootloader_components/*")
+    list(SORT bootloader_component_dirs)
+    foreach(bootloader_component_dir ${bootloader_component_dirs})
+        __component_dir_quick_check(is_component ${bootloader_component_dir})
+        if(is_component)
+            __kconfig_bootloader_component_add("${bootloader_component_dir}")
+        endif()
+    endforeach()
+
     spaces2list(COMPONENTS)
     spaces2list(EXCLUDE_COMPONENTS)
     idf_build_get_property(component_targets __COMPONENT_TARGETS)