Add generic support for link-time registration of struct instances,
modeled after the Zephyr STRUCT_SECTION_* mechanism:
- include/nuttx/iterable_sections.h: STRUCT_SECTION_ITERABLE/DECLARE/
FOREACH/GET/COUNT macros placing instances in name-sorted linker
sections delimited by _<type>_list_start/_end symbols (attributes
through the nuttx/compiler.h macros; FOREACH takes a caller-declared
iterator, like list_for_every_entry).
- include/nuttx/linker/iterable_sections.ld: ITERABLE_SECTION() macro
emitting the KEEP + SORT_BY_NAME collection statements (linker
scripts in ARCHSCRIPT are CPP-preprocessed).
- include/nuttx/linker/common-rom.ld / common-ram.ld: central
aggregators meant to be included by board linker scripts (inside
.text and .data respectively); subsystems register their sections
here guarded by their Kconfig options, so the fragments expand to
nothing on configurations that do not use them.
- CONFIG_ITERABLE_SECTIONS_LINKER_INSERT + include/nuttx/linker/
common-insert.ld (added before the board script by tools/Config.mk and
by the top-level CMakeLists.txt): optional zero-touch mode that
supplements the board script through GNU ld INSERT AFTER, collecting
the subsystems' ITERABLE_SECTION blocks in one output section; the
common-rom.ld/common-ram.ld fragments expand to nothing in that mode.
See the option help for the constraints.
- Documentation/components/iterable_sections.rst.
First user: the Zephyr zbus message bus port (apps/system/zbus in
nuttx-apps); its board integration comes in a companion PR.
Signed-off-by: Jorge Guzman <jorge.gzm@gmail.com>
- migrated /README are removed from /boards
- there are a lot of READMEs that should be further converted to rst.
At the moment they are moved to Documentation/platforms and included in rst files
