esp-idf/components/esp_system/system_init_fn.txt

# This file documents the expected order of execution of ESP_SYSTEM_INIT_FN functions.
#
# When adding new ESP_SYSTEM_INIT_FN functions or changing init priorities of existing functions,
# keep this file up to date. This is checked in CI.
# When adding new functions or changing the priorities, please read the comments and see if
# they need to be updated to be consistent with the changes you are making.
#
# Entries are ordered by the order of execution (i.e. from low priority values to high ones).
# Each line has the following format:
#   stage: prio: function_name in path/to/source_file on affinity_expression
# Where:
#   stage: which startup stage the function is executed in (CORE or SECONDARY)
#   prio: priority value (higher value means function is executed later)
#   affinity_expression: bit map of cores the function is executed on


########### CORE startup stage ###########
# [refactor-todo]: move init calls into respective components

# Log some information about the system
CORE:  10: init_show_cpu_freq in components/esp_system/startup_funcs.c on BIT(0)
CORE:  20: init_show_app_info in components/esp_system/startup_funcs.c on BIT(0)

# Initialize heap allocator. WARNING: This *needs* to happen *after* the app cpu has booted.
# If the heap allocator is initialized first, it will put free memory linked list items into
# memory also used by the ROM. Starting the app cpu will let its ROM initialize that memory,
# corrupting those linked lists. Initializing the allocator *after* the app cpu has booted
# works around this problem.
# With SPI RAM enabled, there's a second reason: half of the SPI RAM will be managed by the
# app CPU, and when that is not up yet, the memory will be inaccessible and heap_caps_init may
# fail initializing it properly.
CORE: 100: init_heap in components/esp_system/startup_funcs.c on BIT(0)

# When apptrace module is enabled, there will be SEGGER_SYSVIEW calls in the newlib init.
# SEGGER_SYSVIEW relies on apptrace module
# apptrace module uses esp_timer_get_time to determine timeout conditions.
# esp_timer early initialization is required for esp_timer_get_time to work.
CORE: 101: init_timer in components/esp_system/startup_funcs.c on BIT(0)

CORE: 102: init_newlib in components/newlib/newlib_init.c on BIT(0)
CORE: 103: init_psram_heap in components/esp_system/startup_funcs.c on BIT(0)
CORE: 104: init_brownout in components/esp_system/startup_funcs.c on BIT(0)
CORE: 105: init_newlib_time in components/esp_system/startup_funcs.c on BIT(0)

# Peripheral-specific implementation operators should be filled first
# Then register vfs console, and follow by newlib stdio initialization
CORE: 110: init_vfs_uart in components/esp_driver_uart/src/uart_vfs.c on BIT(0)
CORE: 111: init_vfs_usj in components/esp_driver_usb_serial_jtag/src/usb_serial_jtag_vfs.c on BIT(0)
CORE: 112: init_vfs_usj_sec in components/esp_driver_usb_serial_jtag/src/usb_serial_jtag_vfs.c on BIT(0)
CORE: 114: init_vfs_console in components/vfs/vfs_console.c on BIT(0)
CORE: 115: init_newlib_stdio in components/newlib/newlib_init.c on BIT(0)

CORE: 120: init_pthread in components/esp_system/startup_funcs.c on BIT(0)
CORE: 130: init_flash in components/esp_system/startup_funcs.c on BIT(0)
CORE: 140: init_virtual_efuse in components/esp_system/startup_funcs.c on BIT(0)
CORE: 150: init_secure in components/esp_system/startup_funcs.c on BIT(0)
CORE: 160: init_rom_log in components/esp_system/startup_funcs.c on BIT(0)
CORE: 170: init_xt_wdt in components/esp_system/startup_funcs.c on BIT(0)


########### SECONDARY startup stage ###########

# esp_timer has to be initialized early, since it is used by several other components
SECONDARY: 100: esp_timer_startup_init in components/esp_timer/src/esp_timer.c on ESP_TIMER_INIT_MASK

# HW stack guard via assist-debug module.
SECONDARY: 101: esp_hw_stack_guard_init in components/esp_system/hw_stack_guard.c on ESP_SYSTEM_INIT_ALL_CORES

# esp_sleep doesn't have init dependencies
SECONDARY: 105: esp_sleep_startup_init in components/esp_hw_support/sleep_gpio.c on BIT(0)
SECONDARY: 106: sleep_clock_startup_init in components/esp_hw_support/sleep_clock.c on BIT(0)
SECONDARY: 107: sleep_sys_periph_startup_init in components/esp_hw_support/sleep_system_peripheral.c on BIT(0)

# app_trace has to be initialized before systemview
SECONDARY: 115: esp_apptrace_init in components/app_trace/app_trace.c on ESP_SYSTEM_INIT_ALL_CORES
SECONDARY: 120: sysview_init in components/app_trace/sys_view/esp/SEGGER_RTT_esp.c on BIT(0)

# the rest of the components which are initialized from startup_funcs.c
# [refactor-todo]: move init calls into respective components
SECONDARY: 200: init_dbg_stubs in components/esp_system/startup_funcs.c on BIT(0)
SECONDARY: 201: init_pm in components/esp_system/startup_funcs.c on BIT(0)
SECONDARY: 202: init_coredump in components/esp_system/startup_funcs.c on BIT(0)
SECONDARY: 203: init_apb_dma in components/esp_system/startup_funcs.c on BIT(0)
SECONDARY: 204: init_coexist in components/esp_system/startup_funcs.c on BIT(0)
SECONDARY: 205: init_cxx_exceptions in components/esp_system/startup_funcs.c on BIT(0)

# usb_console needs to create an esp_timer at startup.
# This can be done only after esp_timer initialization (esp_timer_startup_init).
SECONDARY: 220: esp_usb_console_init_restart_timer in components/esp_system/port/usb_console.c on BIT(0)

# usb_serial_jtag needs to create and acquire a PM lock at startup.
# This makes more sense to be done after esp_pm_impl_init (called from init_pm).
SECONDARY: 230: usb_serial_jtag_conn_status_init in components/esp_driver_usb_serial_jtag/src/usb_serial_jtag_connection_monitor.c on BIT(0)

# Has to be the last step!
# Now that the application is about to start, disable boot watchdog
SECONDARY: 999: init_disable_rtc_wdt in components/esp_system/startup_funcs.c on BIT(0)

# DO NOT add new init functions here. Add them to the correct stage above.