Commit graph

3594 commits

Author SHA1 Message Date
Alin Jerpelea
46e0f6f698 Documentation: add NuttX 13.0.1 release notes
add release notes for NuttX 13.0.1 release

Signed-off-by: Alin Jerpelea <alin.jerpelea@sony.com>
2026-08-12 21:53:05 +08:00
raiden00pl
60ddd837c7 !arch/arm/src/stm32: unify the timer input clock board options
Replace the divergent board conventions for the timer input clock
frequency with a single uniform convention provided by every board:

- STM32_APBx_TIMn_CLKIN and BOARD_TIMn_FREQUENCY -> STM32_TIMn_CLKIN
- STM32_APBx_LPTIMn_CLKIN, BOARD_LPTIMn_FREQUENCY and
  STM32_LPTIMn_FREQUENCY -> STM32_LPTIMn_CLKIN
- STM32_APB1_THRTIM1_CLKIN and BOARD_HRTIM1_FREQUENCY ->
  STM32_HRTIM1_CLKIN

All STM32 consumers (tim/lptim/pwm/adc/dac/capture/sdadc/dfsdm/
pulsecount) updated to match; the timer input clock is now bus-agnostic
in the drivers.

Boards that carried the same timer clock in more than one convention now
define STM32_TIMn_CLKIN exactly once, derived from the APB bus clock
(PCLKx with the x2 doubler when the APB prescaler is greater than 1),
instead of redefining it with a second, sometimes different, value.

BREAKING CHANGE: The timer input-clock board macros STM32_APBx_TIMn_CLKIN,
BOARD_TIMn_FREQUENCY, STM32_APBx_LPTIMn_CLKIN, BOARD_LPTIMn_FREQUENCY,
STM32_LPTIMn_FREQUENCY, STM32_APB1_THRTIM1_CLKIN and
BOARD_HRTIM1_FREQUENCY are removed in favor of STM32_TIMn_CLKIN,
STM32_LPTIMn_CLKIN and STM32_HRTIM1_CLKIN.  Out-of-tree boards must
define the new macros (drop the APB bus from the name, keep the value),
and out-of-tree drivers referencing the old names must be updated.

Signed-off-by: raiden00pl <raiden00@railab.me>
2026-08-07 12:49:07 -03:00
Peter Barada
83cfeb7c4e crypto: Support SHA2_224_HMAC
Since already have support for SHA2-224, extend cryptodev/cryptosoft
to support HMAC version of SHA2-224.

Signed-off-by: Peter Barada <peter.barada@gmail.com>
2026-08-06 17:48:23 +08:00
Xiang Xiao
db9531fe96 drivers/serial: add job-control TTY ioctls and libc wrappers
NuttX has no real session/process-group abstraction, so the TTY layer
collapses the foreground process group onto the single dev->pid field
(pgrp == pid, one member per group).  Extend the controlling-terminal
support so portable software (e.g. dropbear, socat) that relies on
job-control primitives works without losing the existing NuttX-specific
behaviour.

Driver (serial.c, pty.c):
- TIOCSCTTY now accepts a flag: arg > 0 keeps the historical "target
  PID in arg" semantics (NSH registers the foreground command it just
  spawned), while arg == 0 selects the calling task via
  nxsched_getpid(), matching the POSIX flag convention used by
  dropbear/socat/apue.  This preserves all existing callers and makes
  the previously-dead arg==0 path deliver SIGINT correctly.
- Add TIOCGPGRP/TIOCGSID (return dev->pid) and TIOCSPGRP (set it).
- pty.c gains the same handlers against pd_pid and includes
  nuttx/sched.h for nxsched_getpid().

ioctl numbers (tioctl.h): TIOCGPGRP/TIOCSPGRP/TIOCGSID at 0x37-0x39.

libc wrappers:
- termios: tcgetpgrp(), tcsetpgrp(), tcgetsid() over the new ioctls.
- unistd: setsid()/getsid()/setpgid() stubs consistent with the
  existing getpgrp()/getpgid() single-session model (sid == pgid ==
  pid; setpgid only succeeds for pgid == pid).

Declare the new prototypes in unistd.h (tcgetsid was already in
termios.h) and register all sources in the Make.defs/CMakeLists.

Group-broadcast signalling (kill(-pgrp)) remains unsupported, so
tty signals still target the single dev->pid; a real session/process
group model is left as a follow-up.

Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>
2026-08-06 17:48:04 +08:00
Felipe Moura
d70e6735e9 Documentation/netutils/dropbear: add Dropbear SSH server documentation
Add application-level documentation for the Dropbear SSH server port,
covering prerequisites, configuration options, usage and troubleshooting.

Signed-off-by: Felipe Moura <moura.fmo@gmail.com>
2026-08-05 15:26:28 +02:00
Abhishek Mishra
87d12f458e Documentation: PBKDF2 login docs, board Kconfig, and CI password
Document PBKDF2-HMAC-SHA256 ROMFS passwd generation and update board
Kconfig help text accordingly.  Set the documented sim/login CI credential
in GitHub Actions.

Enable CONFIG_CODECS_BASE64 and CONFIG_NETUTILS_CODECS on sim:dropbear for
link compatibility with dropbear's bundled libtomcrypt.

Signed-off-by: Abhishek Mishra <mishra.abhishek2808@gmail.com>
2026-08-05 15:26:28 +02:00
Felipe Moura
7c88a4a631 Documentation/stm32f746g-disco: document Dropbear SSH server setup
Document the new stm32f746g-disco:dropbear configuration, mirroring
the existing esp32c3-devkit Dropbear documentation.

Signed-off-by: Felipe Moura <moura.fmo@gmail.com>
2026-08-05 15:26:28 +02:00
Felipe Moura
2edfa031e6 boards/esp32c3-devkit: Remove Dropbear SSH server support
Drop the esp32c3-devkit:dropbear defconfig and its documentation.
The companion apps#3636 (Dropbear over /dev/crypto for this board)
is stuck on an unrelated Espressif CI dependency issue, and the
port is moving to different hardware.

Signed-off-by: Felipe Moura <moura.fmo@gmail.com>
2026-08-05 15:26:28 +02:00
Felipe Moura
44ef93ac56 Documentation/esp32c3-devkit: document Dropbear SSH server setup
Describe how to enable and use the Dropbear SSH server on the ESP32-C3
DevKit, including Wi-Fi, host key, and login configuration.

Signed-off-by: Felipe Moura <moura.fmo@gmail.com>
2026-08-05 15:26:28 +02:00
Felipe Moura
00ac49d5a3 Documentation/sim: document dropbear configuration
Describe how to build and use the Dropbear SSH server configuration on
the simulator, including host TAP network setup, user creation and the
volatile /tmp host key/passwd caveat.

Signed-off-by: Felipe Moura <moura.fmo@gmail.com>
2026-08-05 15:26:28 +02:00
Abhishek Mishra
2ecbd0026b docs/nsh: document id, su, whoami, and privilege prompt markers
Document NSH identity commands and how login/su update the prompt
(# for effective root, $ for non-root). Cover flat-build euid
semantics, related Kconfig options, and session identity behavior
 after login.
2026-08-05 15:26:28 +02:00
Abhishek Mishra
102f96859e boards: add CI ROMFS passwd credentials and refresh docs
Support NUTTX_ROMFS_PASSWD_PASSWORD via update_romfs_password.sh for
configs that enable ROMFS passwd without a defconfig password (sim/login
CI). Enable RANDOMIZE_KEYS in sim/login defconfig. Update mkpasswd.c
header, platform docs, and the mkpasswd_autogen guide.

Signed-off-by: Abhishek Mishra <mishra.abhishek2808@gmail.com>
2026-08-05 15:26:28 +02:00
Abhishek Mishra
9a30bf8527 !boards: enforce secure ROMFS passwd and TEA key setup
Remove implicit default credentials and add build-time validation.
Add check_passwd_keys.sh and gen_passwd_keys.sh; run key setup via
passwd_keys.mk before config.h is generated. Mirror the same logic in
cmake/nuttx_add_romfs.cmake for CMake builds.

BREAKING CHANGE: Builds with CONFIG_BOARD_ETC_ROMFS_PASSWD_ENABLE=y now
require an explicit admin password and non-default TEA keys. The
Kconfig default password "Administrator" and default TEA keys are no
longer accepted. Fix: run make menuconfig, set Admin password under
Board Selection -> Auto-generate /etc/passwd, enable random TEA keys or
set CONFIG_FSUTILS_PASSWD_KEY1..4 manually, and use NSH login with
Encrypted password file verification.

Signed-off-by: Abhishek Mishra <mishra.abhishek2808@gmail.com>
2026-08-05 15:26:28 +02:00
Alin Jerpelea
1017d76dd9 Revert "!boards: enforce secure ROMFS passwd and TEA key setup"
This reverts commit f5291a8df1.

Signed-off-by: Alin Jerpelea <alin.jerpelea@sony.com>
2026-08-05 15:26:28 +02:00
fangyibo
6c4adb118e Documentation/audio: document the audio upper half interface
The audio subsystem page listed the source files and the configuration
options, but nothing about the interface the upper half presents to
applications.  PR #18348 added a device state machine, a second buffer
allocation mode, poll and mmap support and several new ioctls, none of
which were described anywhere, so the only way to learn the expected
call sequence was to read audio/audio.c.

Document what the upper half now guarantees:

  - the device state machine, and the fact that AUDIOIOC_START is
    rejected until AUDIOIOC_CONFIGURE has moved the device out of
    AUDIO_STATE_OPEN;
  - the normal open/configure/allocate/enqueue/start sequence;
  - the two AUDIOIOC_ALLOCBUFFER modes selected by u.pbuffer, who owns
    the buffers in each, and that a shared ring request may return zero
    when the ring is already populated;
  - that AUDIOIOC_GETBUFFERINFO also establishes the shared ring depth,
    so a lower half which does not implement it disables that mode;
  - the poll event semantics and how mmap() selects between a ring
    buffer and the device status by requested length;
  - all ioctls handled by the upper half, grouped by purpose;
  - how per-open state is aggregated into the device state when several
    applications share one device.

No functional change.

Signed-off-by: fangyibo <fangyibo@xiaomi.com>
2026-08-05 16:00:32 +08:00
Matteo Golin
c61dd58d56 docs/raspberrypi-4b: Documentation about the SD card updated
Updated the documentation to reflect the fix of buggy SD card behaviour
at the sacrifice of slower performance.

Signed-off-by: Matteo Golin <matteo.golin@gmail.com>
2026-08-03 20:57:47 +08:00
Felipe Moura
71dfc30922 Documentation/examples/rng90: add RNG90 application documentation
Document configuration, usage, Kconfig enable path, and hardware validation for the RNG90 example.

Signed-off-by: Felipe Moura <moura.fmo@gmail.com>
2026-08-03 17:23:22 +08:00
hanzhijian
1aefe1c486 Documentation: describe drivertest coverage
Explain how drivertest applications are selected and run, list the current test categories, and document the watchdog reset and notifier test behavior.

Assisted-by: OpenAI Codex
Signed-off-by: hanzhijian <hanzhijian@zepp.com>
2026-08-03 17:22:37 +08:00
hanzhijian
273c77128b fix: remove cross-reference to ip6tables doc not yet in tree 2026-07-16 09:06:26 +02:00
hanzhijian
c3ef6c6fef fix: replace :kconfig:option: with plain backticks for Sphinx compatibility 2026-07-16 09:06:26 +02:00
hanzhijian
940b3d457c Documentation/applications/system/iptables: add iptables man page
Add comprehensive documentation for the iptables command including
all supported commands, options, and usage examples.

Signed-off-by: hanzhijian <hanzhijian@zepp.com>
2026-07-16 09:06:26 +02:00
hanzhijian
2874b429f3 fix: remove extra backtick in See Also doc reference 2026-07-13 16:43:42 +08:00
hanzhijian
47be50d5fc fix: replace :kconfig:option: with plain backticks for Sphinx compatibility 2026-07-13 16:43:42 +08:00
hanzhijian
8f7a612ab4 Documentation/applications/system/ip6tables: add ip6tables man page
Add comprehensive documentation for the ip6tables command including
all supported commands, options, and IPv6-specific usage examples.

Signed-off-by: hanzhijian <hanzhijian@zepp.com>
2026-07-13 16:43:42 +08:00
Abhishek Mishra
f5291a8df1 !boards: enforce secure ROMFS passwd and TEA key setup
Remove implicit default credentials and add build-time validation.
Add check_passwd_keys.sh and gen_passwd_keys.sh; run key setup via
passwd_keys.mk before config.h is generated. Mirror the same logic in
cmake/nuttx_add_romfs.cmake for CMake builds.

BREAKING CHANGE: Builds with CONFIG_BOARD_ETC_ROMFS_PASSWD_ENABLE=y now
require an explicit admin password and non-default TEA keys. The
Kconfig default password "Administrator" and default TEA keys are no
longer accepted. Fix: run make menuconfig, set Admin password under
Board Selection -> Auto-generate /etc/passwd, enable random TEA keys or
set CONFIG_FSUTILS_PASSWD_KEY1..4 manually, and use NSH login with
Encrypted password file verification.

Signed-off-by: Abhishek Mishra <mishra.abhishek2808@gmail.com>
2026-07-06 12:04:07 -03:00
Jukka Laitinen
3498bf1a5a Documentation: Add documentation of SCHED_DUMP_TASKS and SCHED_DUMP_STACK
Add documentation for controlling the crash dump verbosity.

Signed-off-by: Jukka Laitinen <jukka.laitinen@tii.ae>
2026-07-04 13:29:32 -04:00
Eren Terzioglu
958169e1ec Docs/platforms/esp32[-c6|-h2]: Add BLE docs for esp32[-c6|-h2]
Add BLE docs for esp32c6 and esp32h2

Signed-off-by: Eren Terzioglu <eren.terzioglu@espressif.com>
2026-07-04 02:00:32 +08:00
Matteo Golin
f725c1932c docs/sim: Include documentation about NXDoom configuration
Include docs about new NXDoom configurations for playing NXDoom.

Signed-off-by: Matteo Golin <matteo.golin@gmail.com>
2026-07-04 01:59:40 +08:00
Matteo Golin
1c9f89d0df docs/games/NXDoom: Documentation for DOOM port
Includes documentation about the current state of the DOOM port, where
it came from, how to play and what the requirements are. Includes all of
the warnings about experimental/unfinished features.

Signed-off-by: Matteo Golin <matteo.golin@gmail.com>
2026-07-04 01:59:40 +08:00
raiden00pl
bfad0f1f4d Documentation: add STM32 porting guide
add STM32 porting guide

Signed-off-by: raiden00pl <raiden00@railab.me>
2026-07-03 10:27:27 +08:00
raiden00pl
db5afb356e !arch/stm32: move stm32l1 and finalize the directory split
Move the stm32l1 sources, headers and boards into arch/arm/src/stm32l1,
arch/arm/include/stm32l1 and boards/arm/stm32l1, then finalize the split:
source each split family directly in arch/arm/Kconfig and boards/Kconfig and
remove the now-empty combined arch/arm/src/stm32 and boards/arm/stm32 trees.

BREAKING CHANGE: The legacy STM32 architecture and board paths were split into
stm32f1, stm32l1, stm32f2, stm32f3, stm32f4, and stm32g4 directories.
Out-of-tree boards must move from stm32 to the matching split family.

Signed-off-by: raiden00pl <raiden00@railab.me>
2026-07-03 10:27:27 +08:00
raiden00pl
bf30992c2c !arch/stm32: move common sources to common/stm32
BREAKING CHANGE: Common STM32 source and private header files moved to
arch/arm/src/common/stm32. Out-of-tree code that references family-local
common source paths must update includes, build rules, and source paths
to the new common STM32 location.

Signed-off-by: raiden00pl <raiden00@railab.me>
2026-07-03 10:27:27 +08:00
raiden00pl
b919ee2a83 !boards/arm/stm32: move common board sources
BREAKING CHANGE: Move the existing STM32 board common sources to
boards/arm/common/stm32 and fold in the common STM32F0/L0/G0/C0
board helpers so split STM32 board families can share one source
tree.

Signed-off-by: raiden00pl <raiden00@railab.me>
2026-07-03 10:27:27 +08:00
Jorge Guzman
f049deb0d6 Documentation/spresense: rewrite board page with images and configs
Replace the bare "README.txt literal include" with a proper reStructuredText
page for the Sony Spresense board, and remove the now-redundant README.txt
(all of its content has been migrated into index.rst):

- Add board, extension and camera pinout figures (sony*.png).
- Add Features, Serial Console, Buttons and LEDs sections.
- Add "Flashing the bootloader" and "Building and Flashing" sections,
  including the official firmware download link and the flash_writer.py
  workflow.
- Document all board configurations (audio, audio_sdk, camera, charger,
  coremark, elf, example_camera, example_lcd, fmsynth, getprime, lcd, lte,
  module, mpy, nsh, nsh_automount, nsh_trace, ostest, posix_spawn, rndis,
  rndis_composite, rndis_smp, smp, usbmsc, usbnsh, wifi, wifi_smp), each of
  which was verified to build.

Signed-off-by: Jorge Guzman <jorge.gzm@gmail.com>
2026-07-02 10:30:30 -03:00
raiden00pl
a42f07052b !arm/stm32: split legacy STM32 family selectors
BREAKING CHANGE: Convert the legacy STM32 F1/F2/F3/F4/G4/L1 port to the concrete
family selectors while keeping the shared STM32 selector hidden.

Legacy STM32 family selector Kconfig symbols were split by
concrete STM32 sub-family. Out-of-tree defconfigs and code must update
CONFIG_ARCH_CHIP_* selections to the new family-specific selectors.

Signed-off-by: raiden00pl <raiden00@railab.me>
2026-07-02 10:27:21 -03:00
Alin Jerpelea
1bcfc25d45 Documentation: add NuttX 13.0.0 release notes
add release notes for NuttX 13.0.0 release

Signed-off-by: Alin Jerpelea <alin.jerpelea@sony.com>
2026-06-25 19:47:40 +08:00
raiden00pl
dd0c546eac !arch/stm32u5: use common STM32 Kconfig symbols
BREAKING CHANGE: STM32U5 Kconfig symbols were renamed from CONFIG_STM32U5_* to CONFIG_STM32_*.
Out-of-tree code must update defconfigs and Kconfig references to the new CONFIG_STM32_* names.
The custom clock option is a special breaking case that does not follow the family-to-common pattern:
CONFIG_ARCH_BOARD_STM32U5_CUSTOM_CLOCKCONFIG was renamed to CONFIG_ARCH_BOARD_STM32_CUSTOM_CLOCKCONFIG.

Signed-off-by: raiden00pl <raiden00@railab.me>
2026-06-24 23:14:35 +08:00
raiden00pl
0c41b13966 !arch/stm32l5: use common STM32 Kconfig symbols
BREAKING CHANGE: STM32L5 Kconfig symbols were renamed from CONFIG_STM32L5_* to CONFIG_STM32_*.
Out-of-tree code must update defconfigs and Kconfig references to the new CONFIG_STM32_* names.
The custom clock option is a special breaking case that does not follow the family-to-common pattern:
CONFIG_ARCH_BOARD_STM32L5_CUSTOM_CLOCKCONFIG was renamed to CONFIG_ARCH_BOARD_STM32_CUSTOM_CLOCKCONFIG.

Signed-off-by: raiden00pl <raiden00@railab.me>
2026-06-24 23:14:35 +08:00
raiden00pl
a7bd8799b7 !arch/stm32l4: use common STM32 Kconfig symbols
BREAKING CHANGE: STM32L4 Kconfig symbols were renamed from CONFIG_STM32L4_* to CONFIG_STM32_*.
Out-of-tree code must update defconfigs and Kconfig references to the new CONFIG_STM32_* names.
The custom clock option is a special breaking case that does not follow the family-to-common pattern:
CONFIG_ARCH_BOARD_STM32L4_CUSTOM_CLOCKCONFIG was renamed to CONFIG_ARCH_BOARD_STM32_CUSTOM_CLOCKCONFIG.

Signed-off-by: raiden00pl <raiden00@railab.me>
2026-06-24 23:14:35 +08:00
raiden00pl
c926b8af0c !arch/stm32h7: use common STM32 Kconfig symbols
BREAKING CHANGE: STM32H7 Kconfig symbols were renamed from CONFIG_STM32H7_* to CONFIG_STM32_*.
Out-of-tree code must update defconfigs and Kconfig references to the new CONFIG_STM32_* names.
The custom clock option is a special breaking case that does not follow the family-to-common pattern:
CONFIG_STM32H7_CUSTOM_CLOCKCONFIG was renamed to CONFIG_ARCH_BOARD_STM32_CUSTOM_CLOCKCONFIG.

Signed-off-by: raiden00pl <raiden00@railab.me>
2026-06-24 23:14:35 +08:00
raiden00pl
4f093cc1dd !arch/stm32h5: use common STM32 Kconfig symbols
BREAKING CHANGE: STM32H5 Kconfig symbols were renamed from CONFIG_STM32H5_* to CONFIG_STM32_*.
Out-of-tree code must update defconfigs and Kconfig references to the new CONFIG_STM32_* names.
The custom clock option is a special breaking case that does not follow the family-to-common pattern:
CONFIG_ARCH_BOARD_STM32H5_CUSTOM_CLOCKCONFIG was renamed to CONFIG_ARCH_BOARD_STM32_CUSTOM_CLOCKCONFIG.

Signed-off-by: raiden00pl <raiden00@railab.me>
2026-06-24 23:14:35 +08:00
raiden00pl
6bd8fe6ab6 !arch/stm32f7: use common STM32 Kconfig symbols
BREAKING CHANGE: STM32F7 Kconfig symbols were renamed from CONFIG_STM32F7_* to CONFIG_STM32_*.
Out-of-tree code must update defconfigs and Kconfig references to the new CONFIG_STM32_* names.
The custom clock option is a special breaking case that does not follow the family-to-common pattern:
CONFIG_STM32F7_CUSTOM_CLOCKCONFIG was renamed to CONFIG_ARCH_BOARD_STM32_CUSTOM_CLOCKCONFIG.

Signed-off-by: raiden00pl <raiden00@railab.me>
2026-06-24 23:14:35 +08:00
Abhishek Mishra
fec3c5bc07 Documentation/sched: Add POSIX user identity transition docs
Adds comprehensive documentation for the POSIX three-tier user identity
model (real, effective, saved-set IDs) enabled by CONFIG_SCHED_USER_IDENTITY.

* Updates sched/Kconfig with detailed help text explaining the config.
* Adds user_identity.rst to formally document credential inheritance
  and the privilege transition rules for setuid(), seteuid(), setgid(),
  and setegid().
* Updates tasks_vs_threads.rst to list credentials as a shared task
  group resource.

Signed-off-by: Abhishek Mishra <mishra.abhishek2808@gmail.com>
2026-06-17 17:13:57 +08:00
Eren Terzioglu
79d80e4918 Docs/platforms: Add missing defconfig docs for esp32[-c3|-c6|-h2]
Add missing defconfig docs for risc-v based Espressif devices
2026-06-17 17:12:14 +08:00
hanzhijian
be8fe68ff7 Documentation/applications/system/conntrack: add conntrack man page
Add comprehensive documentation for the conntrack command including
dump and event monitoring options.

Signed-off-by: hanzhijian <hanzhijian@zepp.com>
2026-06-17 17:12:14 +08:00
hanzhijian
a147b4d6dd Documentation/applications/system/conntrack: add conntrack man page
Add documentation for the conntrack command including usage, options,
output format, and examples for listing and monitoring connection
tracking entries.

Signed-off-by: hanzhijian <hanzhijian@zepp.com>
2026-06-17 17:12:14 +08:00
hanzhijian
56e3e5b354 Documentation/applications/system/critmon: add critmon man page
Add documentation for the critmon command including:
- critmon (one-shot dump)
- critmon_start (start daemon)
- critmon_stop (stop daemon)
- Output format explanation
- Configuration options

Signed-off-by: hanzhijian <hanzhijian@zepp.com>
2026-06-17 17:12:14 +08:00
raiden00pl
49eaa7b860 Documentation: update references to nrfjprog
nrfjprog is no longer maintained. Change all nrfjprog commands
to equivalent nrfutil commands

Signed-off-by: raiden00pl <raiden00@railab.me>
2026-06-17 17:12:14 +08:00
hanzj
81ff8a31ca Documentation: document tcpdump command.
Add documentation for the tcpdump system command, covering
command-line options (-i, -w, -s), Kconfig configuration,
usage examples, and notes on pcap output format compatibility.

Signed-off-by: hanzj <hanzjian@zepp.com>
2026-06-17 17:12:14 +08:00
Kerogit
8ad4f90b72 arch/avr/src/avrdx/avrdx_delay: add custom up_udelay function
NuttX builtin up_udelay function uses BOARD_LOOPSPERMSEC configuration
value to determine how many loops need to be done to cause requested
delay. This does not match well with AVR DA/DB microcontrollers
because the CPU clock frequency is configurable.

A board configuration could therefore provide BOARD_LOOPSPERMSEC
valid for one frequency but for other frequencies, the user would
be required to calibrate the value and would still get incorrect
result when changing the clock speed during runtime.

This patch therefore implements dynamic architecture-specific
up_udelay function which determines current clock settings
and infers required loop count from that.

New function was tested by simple application that used up_udelay
to put delays between printf calls.

Signed-off-by: Kerogit <kr.git@kerogit.eu>
2026-06-17 17:10:02 +08:00