docs/guides/bootsequence: Migrate UML diagram to PlantUML

Removes legacy UML diagram image in favour of PlantUML description using
plain text.

Signed-off-by: Matteo Golin <matteo.golin@gmail.com>
This commit is contained in:
Matteo Golin
2026-02-10 16:58:52 -05:00
committed by Mateusz Szafoni
parent 16aca58275
commit bcf682ccbe
2 changed files with 50 additions and 8 deletions
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The diagram of boot sequence
The diagram of boot sequence
============================
The premise of this sequence diagram is NuttX12.4.0, cxd56xx, non-SMP and Flat build.
The beginning of boot sequence is __start().
__start() will call nx_start(). nx_start() will initialize the kernel and call nsh_main().
nsh_main() will execute NuttShell(NSH).
nx_start() is NuttX standard function, but the behavior depends on some kernel configurations.
For example, the calling nsh_main() is also configurable.
About related kernel configurations, see :doc:`/guides/port_relatedkernelconfigrations`.
The beginning of boot sequence is ``__start()``.
.. image:: image/port_bootsequence-12.4.0.png
``__start()`` will call ``nx_start()``. ``nx_start()`` will initialize the
kernel and call ``nsh_main()``. ``nsh_main()`` will execute NuttShell(NSH).
``nx_start()`` is NuttX standard function, but the behavior depends on some
kernel configurations. For example, the calling ``nsh_main()`` is also
configurable. About related kernel configurations, see
:doc:`/guides/port_relatedkernelconfigrations`.
.. uml::
bootloader --> cxd56_start.c : Jump to __start by function call or de-assert the reset signal of CM4F
note over cxd56_start.c : Initialize SP
note over cxd56_start.c : Disable IRQ @processor level
note over cxd56_start.c : Initialize .data/.bss
note over cxd56_start.c : cxd56_board_initialize() as <arch>_board_initialize()
cxd56_start.c --> nx_start.c : nx_start()
note over nx_start.c : Initialize IDLE task TCB
note over nx_start.c : nxsem_initialize()
note over nx_start.c : Initialize HEAP
note over nx_start.c : Create and initialize IDLE group instance
note over nx_start.c : sched_lock()
note over nx_start.c : fs_initialize()
note over nx_start.c : irq_initialize()
note over nx_start.c : clock_initialize()
note over nx_start.c : timer_initialize()
note over nx_start.c : nxsig_initialize()
note over nx_start.c : nxmq_initialize()
note over nx_start.c : net_initialize()
note over nx_start.c : binfmt_initialize()
note over nx_start.c : up_initialize()
note over nx_start.c : drivers_initialize()
note over nx_start.c : board_early_initialize()
note over nx_start.c : Initialize SDIO for IDLE task
nx_start.c --> nx_bringup.c : nx_bringup()
note over nx_bringup.c : Initialize environment variables (PWD, PATH, LD_LIBRARY_PATH)
note over nx_bringup.c : Start work queues
nx_bringup.c --> nx_start_application : nx_start_task()
note over nx_start_application : board_late_initialize()
note over nx_start_application : coredump_initialize()
note over nx_start_application : Start nsh_main() as the application initialization task
note over nx_start.c : up_idle()