Work In Progress

What's New In This Release

Major Changes to Core OS

New Features

Bug Fixes

Major Changes to the Build System

Architectural Support

New Architecture Support

Architectures With Significant Improvements

Driver Support

New Driver Support

Drivers With Significant Improvements

Networking

Applications

Improvements

Bug Fixes

Security Issues Fixed In This Release

Compatibility Concerns

Changes to Build System

If you have are building NuttX for a custom board, you may need to make some of the following changes in build-related files for your board:

Rename EXTRADEFINES to EXTRAFLAGS

In your custom board's scripts/Make.defs file, rename EXTRADEFINES to EXTRAFLAGS.

For example, these lines:

CFLAGS = $(ARCHCFLAGS) $(ARCHWARNINGS) $(ARCHOPTIMIZATION) $(ARCHCPUFLAGS) $(ARCHINCLUDES) $(ARCHDEFINES) $(EXTRADEFINES) -pipe
...
CXXFLAGS = $(ARCHCXXFLAGS) $(ARCHWARNINGSXX) $(ARCHOPTIMIZATION) $(ARCHCPUFLAGS) $(ARCHXXINCLUDES) $(ARCHDEFINES) $(EXTRADEFINES) -pipe
...
CPPFLAGS = $(ARCHINCLUDES) $(ARCHDEFINES) $(EXTRADEFINES)

would change as follows:

CFLAGS = $(ARCHCFLAGS) $(ARCHWARNINGS) $(ARCHOPTIMIZATION) $(ARCHCPUFLAGS) $(ARCHINCLUDES) $(ARCHDEFINES) $(EXTRAFLAGS) -pipe
...
CXXFLAGS = $(ARCHCXXFLAGS) $(ARCHWARNINGSXX) $(ARCHOPTIMIZATION) $(ARCHCPUFLAGS) $(ARCHXXINCLUDES) $(ARCHDEFINES) $(EXTRAFLAGS) -pipe
...
CPPFLAGS = $(ARCHINCLUDES) $(ARCHDEFINES) $(EXTRAFLAGS)

See git commit # 459ad9937377a42785692098ff0d73baaa9551e6 in the main NuttX repository.

If you forget to do this, memory allocations on the heap probably won't work and your user tasks won't start.

To see why, tools/Config.mk assigns a value to KDEFINE such that the preprocessor symbol __KERNEL__ will be defined when certain source files are compiled. KDEFINE is passed to nested invocations of 'make' as EXTRAFLAGS. If your board's scripts/Make.defs still attempts to use EXTRADEFINES, the preprocessor symbol __KERNEL__ will not be defined in some of the places that it should be. Suppose you're building a FLAT build. In this case, include/nuttx/mm/mm.h will not define MM_KERNEL_USRHEAP_INIT like it should, which will cause nx_start.c not to call up_allocate_heap() at startup. Therefore, any attempt to allocate memory on the heap will fail.

Rename src/Makefile to src/Make.defs and Modify

This item pertains only to custom boards that are developed in-tree, meaning under the NuttX boards/ subdirectory. Out-of-tree boards are not affected.

If your custom board directory is in-tree and in a board family that uses a 'boards/ARCH/FAMILY/common' directory (such as boards/arm/stm32/common, boards/arm/cxd56xx/common, etc), then you'll need to make two minor changes to your custom board's src/Makefile:

(1) Rename it from src/Makefile to src/Make.defs, and

(2) Near the end of that file, replace this line, which usually appears at the end:

include $(TOPDIR)/boards/Board.mk

PR-977 PR-987 PR-998 PR-995 PR-997 PR-1007 Thread Local Storage (TLS) is now a required feature and used by all architectures

There is detailed information on the implementation and how this impacts errno specifically in the Wiki article: Thread Local Storage (TLS)

PR-957 PR-947 PR-963 PR-969 Provide nx_ versions of many functions that are used internally to avoid disrupting errno in userspace

PR-965 PR-980 PR-984 ioctl is now always in the variadic form. Syscalls in KERNEL builds are also more efficient with this as well now.

Previously the ioctl prototype was normally defined as

int ioctl(int fd, int cmd, unsigned long arg);

unless the CONFIG_LIBC_IOCTL_VARIADIC was enabled in which case it was

int ioctl(int fd, int cmd, ...);
This form is now the form defined by opengroup and is also inline with Linux.  Prior to this change there were issues with making ioctl calls on 64-bit arch since the implementation assumed that (void *) would be of size long.  There is more discussion of this issue in the GitHub issue ticket here:

https://github.com/apache/incubator-nuttx/issues/959

PR-962 PR-964 Add new interface sched_get_stackinfo that simplifies interfaces for things like TLS

There are some security imposed rules for using this interface

1. Any thread may query its own stack,
2. A kernel thread may query the stack of any other thread
3. Application threads, however, may query only the stacks of threads within the same task group, i.e., the main thread and any of the child pthreads created with the main thread as a parent or grandparent or great-grandparent.

PR-1104 Internal function fs_fsopen() no longer affects errno

PR-1123 Move task_init() and task_activate() to be internal functions

PR-1140 Add nxtask_uninit() interface

This function will undo all operations on a TCB performed by task_init() and release the TCB by calling kmm_free(). This is intended primarily to support error recovery operations after a successful call to task_init() such was when a subsequent call to task_activate fails.

PR-1134 Add typedef for max_align_t

PR-1141 Handle custom stack allocations

sched_releasetcb() will normally free the stack allocated for a task. However, a task with a custom, user-managed stack may be created using nxtask_init() followed by nxtask_activate(). If such a custom stack is used then it must not be freed in this manner or a crash will most likely result.

This change adds a flag call TCB_FLAG_CUSTOM_STACK that may be passed in the the pre-allocated TCB to nxtask_init(). This flag is not used internally anywhere in the OS except that if set, it will prevent sched_releasetcb() from attempting to free that custom stack.

PR-1164 PR-1173 Implement some missing functions required for latest libc++

• aligned_alloc() posix_memaligned(), timespec_get(), wcsrtombs() wcsnrtombs(), mbsnrtowcs() mblen(), mbstowcs(), wcstombs()

PR-1172 Implement %ju and %jd printf formaters

PR-1179 Implement vscanf()

PR-1182 tmpfile() no longer hardcodes to /tmp path

PR-1186 printf() and vprintf() use buffered IO if available

PR-1174 Add support for mtx_timedlock recursive mutex

PR-1193 Add location directive to compiler.h to support location data in different memory sections

Bug Fixes

Many private architecture interfaces were using 'up_' instead of the arch name 'arm_'

This fix is carried over many PRs such as PR-924.  Many files also carried this same error in naming convention and were converted as well.

PR-1018 PR-1017 PR-1021 PR-1022 PR-1057 PR-1060 PR-1194 Clean up internal APIs that were not using the properly naming conventions

PR-857 Wrong value for it_interval field in timespec returned by timer_gettime

PR-902 SMP: On task creation do not clone uninitialized descriptors

In SMP mode, there is a possibility that a pthread executing one CPU may create a new task while a pthread on another CPU has allocated the socket but not yet initialized it. This commit updates the socket clone test to assure that the socket is both allocated and initialized before it is cloned.

PR-911 Use OS signal functions internally to not reset errno that applications are using

PR-925 sys/stat.h Change the xtime fields to align with POSIX standard.

Starting from Issue 7 of the POSIX standard the fields st_atime, st_mtime and st_ctime have a type of strcut timespec instead of time_t.

PR-939 openamp: Update to 2020.04.0

PR-953 lib_vsprintf: Fix issue where stack would become corrupt on x86_64

This function requires traversing the VA_LIST twice.  For some architectures like x86 and x86_64 this needs to be cloned first.

Major Changes to the Build System

Parts of the build system have been refactored to reduce duplication and simplify Makefile and Make.defs files across many directories. These changes are particularly beneficial for boards.

Please note that if you develop your own custom boards, you may need to make some modifications to keep your board's build scripts up-to-date with the rest of NuttX and avoid a broken or defective build. For details, see Compatibility Concerns, Changes to Build System, in these release notes.

New Features

PR-894 openamp and libmetal can now be downloaded and configured by build system

PR-941 Remove 'u' prefix from userspace library in FLAT Build so it is the same for all build types

PR-1044 ARM: Remove support for old redundant gcc toolchains

This removes support for the Codesourcery, Atollic, DevKitArm, Raisonance, and CodeRed toolchains. Not only are these tools old and no longer used but they are all equivalent to the standard ARM EABI toolchains. Retaining specific support was not meaningful (and they are still supported, but now just as generic EABI toolchains).

PR-1148 PR-1149 Improve build time especially on non-Linux platforms by providing a C version of incdir.sh

Bug Fixes

Many small changes to resolve dependency resolution issues that would sometimes appear during parallel builds.  Parallel builds should be much more reliable now and bugs filed against any issues found.

PR-1000 Fix broken support of ZDS-II Toolchain with MSYS

Architectural Support

New Architecture Support

PR-879 ARMv8-M support

PR-1051 STM32G474 support

Initial architectural support for the STM32G474 family of microcontrollers. In terms of peripherals, currently there is basic support for the RCC and UART, allowing NuttX to boot to a functional NSH prompt on this family. Other peripherals on the SoC are not yet supported and/or not tested yet. Contributions to enable other peripherals are welcome. This adds support for these variants:

• STM32G474C
• STM32G474M
• STM32G474R
• STM32G474Q
• STM32G474V

Architectures With Significant Improvements

PR-745 The full line of STM32H7 chips are now defined

This adds support for these variants:

• STM32H743AG
• STM32H743AI
• STM32H743BG
• STM32H743BI
• STM32H743IG
• STM32H743II
• STM32H743VG
• STM32H743VI
• STM32H743XG
• STM32H743XI
• STM32H743ZG
• STM32H753AI
• STM32H753BI
• STM32H753VI
• STM32H753XI
• STM32H753ZI

PR-811 i486: Fix corruption of esp register on full context restore

This resolves a long standing issue with running the x86 port under QEMU where it would crash shortly after boot.

PR-837 rx65n: Add crashdump support using standby RAM

PR-862 STM32L4: Expose LPTIM timers

PR-868 STM32L4: Extend clock options and power regulation for based on clock settings

• Interface to select the core regulator voltage according to clock frequency range
• Usage of this interface during clock configuration according to chosen clock frequency
• Option to choose a different system clock than the main PLL (there is HSI, MSI, HSE and LSE available to use)
• Option to not enable the main PLL which allows for reduced power usage when setting one of the above options as system clock, to do this you should define STM32L4_BOARD_NOPLL on your board header.

PR-960 STM32: Add support for ADC features EXTSEL and JEXTSEL

PR-1041 STM32H7: Improve IDMA transfer and cache handling

This resolves an issue where the sdmmc driver crashes at boot when using writeback cache.

This also simplifies the sdmmc driver when the IDMA is in use. There is no need to mix
IDMA and interrupt based transfers; instead, when making unaligned data tranfers,
just make IDMA into an internal aligned buffer and then copy the data. This method also enables multiblock transfers, and transfers from/to data buffers which are not
aligned on cache boundary.

PR-1042 STM32H7: Resolve multiple limitations and bugs with progmem especailly for partial memory writes

PR-1045 STM32H7: This gives possibility to send arbitrary number of bytes from memory to peripheral using DMA also when using write-back cache

• It was not possible to DMA to/from AXI sram if CONFIG_STM32H7_DMACAPABLE=y
• When doing TX DMA (e.g. in SPI driver in simplex-tx mode), it should not be necessary to
  align the data buffers to the cache line.

PR-1103 STM32H7: Resolve clocking and pin configurations bugs that could cause SDMMC and ETH to fail in some configurations

PR-1104 STM32H7: Use UUID for Ethernet MAC.  This is inline with the behaviour of STM32F7

PR-1110 STM32H7: Use FDCANSEL to determin FDCAN clock source if possible

PR-1165 STM32H7: SPI transaction appears to be completed before the data has actually been flushed

TX DMA completes before the data has been actually sent out from the SPI fifo. This is expected, but the exchange should actually wait for spi tx to finish instead of dma to the fifo to finish. This replaces the dma completion event with the SPI TXC event for detecting end of transmission.

PR-1203 PR-1204 STM32H7: Enable support for BDMA and enable it for SPI6

PR-905 x86_64: Resolve linking issue when building with gcc 7 and 9.

PR-904 x86_64: Resolve compiler aliasing warnings and RNG pointer cast bug

PR-944 x86_64: Change entrypoint to standard location 1M

PR-971 x86_64: Fix bug in rng implementation using intrinsics

PR-973 x86_64: Fix crash on boot when XSAVE and SSE/AVX is enabled

PR-974 x86_64: Add support booting NuttX as a Jailhouse Cell

PR-919 sim: Add host mmap and perror to allow use of LIBC_MODLIB and BINFMT_LOADABLE

PR-1198 sim: Use correct errno sign with hostfs interface

PR-932 z16: Updated toolchain to ZDS-II 5.2.2

PR-970 K210: Add PLL support

PR-988 K210: Resolve occasional lock in early boot caused by waiting for serial driver to initialize

PR-1205 K210: Add basic GPIOHS support

PR-1112 tiva: Add up_idle support

PR-1116 NRF52832: Work around chip eratta for SPI Master 1 Byte transfer anomaly

PR-1130 imxrt: Resolve WFI issue by setting the low power mode to remain in run mode

PR-1197 cxd56: Fix locking issue in Spresense audio driver causes by using semaphore in DMA buffer handling code

PR-1221 Add INTx_C macro defintion

Driver Support

Bug Fixes

PR-1206 PR-1207 PR-1210 ioctl function should retun ENOTTY when the command is not recognized.

New Driver Support

PR-795 PR-1001 Initial NuttX audio driver supporting the Spresense CXD56

PR-975 Support for HDC1008 temperature and humidity sensor

PR-1201 Support for the CS4344 stereo audio DAC

PR-1145 Support for the FTDI FT232R USB to Serial converter

PR-1052 gs2200m: Add max payload size to prevent crashing when sending large packets

PR-1090 gs2200m: Fix possible packet queue count overflow seen during streaming

PR-1127 gs2200m: Resolve possible buffer overrun in packet parsing

PR-1167 pty: Return correct number of bytes when CONFIG_SERIAL_TERMIOS and OPOST|ONLCR are enabled

Drivers With Significant Improvements

PR-887 PR-888 rptun: Add control for independent control of rx and tx buffer size

PR-917 gs2200m: Receive performance improvement for TCP/UDP

PR-1032 gs2200m: Add SPI-DMA support to spresense

PR-1046 gs2200m: Add getsockname() support

PR-1094 PR-1163 gs2200m: Add flow control support to prevent memory starvation in changing network environments

PR-1101 gs2200m: Add WPA2-PSK AP mode support, this is now the default instead of WEP

PR-1115 SPI slave: Improve interface

• Enable enqueue and receive full buffers of data with single call, to avoid call overhead when sending / receiving large amounts of data.

• Enable the slave device to leave received data in the controller receive buffers and retrieve it from there by polling

PR-1196 Audio: Add support for using ap_buffer_info without CONFIG_AUDIO_DRIVER_SPECIFIC_BUFFERS and return ENOTTY if provided ioctl is not supported

PR-1222 audio/cxd56: Add audio buffering feature.

Board Support

Significant Improvements

PR-1200 The boards_button_initialize and boards_userled_initialize functions now return the number of buttons and leds, thus their prototypes have changed from

void board_button_initialize(void) and void board_userled_initialize(void) to uint32_t board_button_initialize(void) and uint32_t board_userled_initialize(void).

New Board Support

PR-1051 ST Micro B-G474E-DPOW1 Discovery Kit

Initial support for the ST Micro B-G474E-DPOW1 Discovery Kit with STM32G474RE MCU. Currently there is basic support for booting NuttX to a functional NSH prompt. Other peripherals on the board are not yet supported or not tested yet. Contributions to enable other peripherals are welcome. The NSH prompt can be accessed from a host computer via a Virtual COM Port over the same Micro-USB Type B connection used for programming/debugging.

PR-1211  STM32F411-Minimum board (a.k.a. BlackPill)

Initial support for the BlackPill board which is a low cost STM32F411 board.  The current support boots NuttX to a functional NSH prompt.

Boards With Significant Improvements

PR-949 qemu-intel64: Add nsh configuration for testing QEMU virtualization

PR-966 qemu-i486: Fix issue where console would not accept input because of wrong IRQ number

PR-993 stm32h747i-disco: Add support for FMC SDRAM

PR-1029 maix-bit: Add knsh configuration for testing Kernel mode under QEMU virtualization

PR-1056 stm32h747i-disco: Add support for FAT and SD Card via SDMMC

PR-1070 PR-1086 spresense: Add ftpd/ftpc and nxplayer to wifi and rndis configurations

PR-1084 imxrt1060-evk: Add dns client and renew command to netnsh configuration

PR-1113 lm3s6965ek: Use proper sysclock for QEMU configuration

PR-1229 Add support for the inboard joystick

PR-1232 Architectural re-organization to the initialization of the video stream driver to comply with other NuttX drivers

File System

Bug Fixes

PR-918 tmpfs: Calling statfs could cause files to be removed recursively

PR-1142 NFS: Use of uint64_t causes issues with gaps in data since it must be on a 8 byte boundary

PR-1143 Report correct stats for proxied block and MTD drivers

Significant Improvements

PR-793 Allow use of genromfs to geneate ROMFS

Previously nsh_romfsimg.h would have to be created manually or using mkromfs.sh.  Now the file structure can be defined in the Makefile.

Here is a demo boards/arm/chip/board/src/Makefile

RCSRCS := rcS
VPATH += :etc/init.d
DEPPATH += --dep-path etc/init.d
include $(TOPDIR)/boards/Board.mk

And boards/arm/chip/board/src/etc/init.d/rcS

#include <nuttx/config.h>
#ifdef CONFIG_NSH_PROC_MOUNTPOINT
mount -t procfs CONFIG_NSH_PROC_MOUNTPOINT
#endif
#ifdef CONFIG_FS_TMPFS
mount -t tmpfs CONFIG_LIBC_TMPDIR
#endif
#ifndef CONFIG_NSH_DISABLE_UNAME
uname -a > /dev/syslog
#endif

PR-851 Upgrade littlefs to v2.2.1

PR-1154 FATFS: Do not rewrite the root directory if it has not been changed.

PR-1120 PR-1118 Fill in file size for mtd and block inode

Networking

PR-807 Netlink: Broadcast link status changes to userspace via RTNLGRP_LINK

PR-892 Netdb: Multiple DNS Servers

PR adds capability to add multiple nameservers on run-time even when not using resolv.conf and reset the list of nameservers back to default setting (no nameserver at all or single predefined nameserver in Kconfig). This is useful for applications that change their cellular network frequently.

PR-1015 tcp/conn: Request ARP before 3-way handshake

Applications

Improvements

PR-185 PR-828 nshlib

• Add the source command.
• Avoid use of sh where it is not needed since it pollutes the parent environment including the working directory and variables.

PR-236 littlevgl: Add additional config mappings to the library

PR-264 nxplayer: Add max host and filename for http url

PR-260 nshlib: Add wget buffer size control with CONFIG_NSH_WGET_BUFF_SIZE

PR-243 dhcpd: Add ability for daemon to be cancelled

PR-238 Remove use the set_errno this is now properly handled by the libc and OS

PR-233 hdc1008: Add example application for this driver

Bug Fixes

PR-282 netlib: Fix pathlen computation for netlib_parseurl and netlib_parsehttpurl

PR-281 webclient: Check return value of netlib_parseurl correctly

PR-278 webclient: Handle http→https redirection correctly

PR-277 webclient: Limit the number of http redirects

PR-198 webclient: Use getaddrinfo() to get IPv4 address on dual stack systems

PR-268 ftpd: Fix EPSV mode for IPv4

PR-258 nsh: Always try FILE_APPS even if the command is builtin, this is a regression introduced in 9.0.0

PR-257 gs2200m: Handle packets over 1500 Bytes, previously would overflow buffer

PR-221 gs2200m: Server sockets were not properly being released by the daemon when close() was called

PR-248 dhcpd: Correct option header check length

PR-176 cu: Handle NULL character correctly

PR-287 PR-290 examples: Update nxflat and thttpd Makefile's to fix a build breakage.

Security Issues Fixed In This Release

Compatibility Concerns

Changes to Build System

If you are building NuttX for a custom board, you may need to make some of the following changes in build-related files for your board:

Rename EXTRADEFINES to EXTRAFLAGS

In your custom board's scripts/Make.defs file, rename EXTRADEFINES to EXTRAFLAGS.

For example, these lines:

CFLAGS = $(ARCHCFLAGS) $(ARCHWARNINGS) $(ARCHOPTIMIZATION) $(ARCHCPUFLAGS) $(ARCHINCLUDES) $(ARCHDEFINES) $(EXTRADEFINES) -pipe
...
CXXFLAGS = $(ARCHCXXFLAGS) $(ARCHWARNINGSXX) $(ARCHOPTIMIZATION) $(ARCHCPUFLAGS) $(ARCHXXINCLUDES) $(ARCHDEFINES) $(EXTRADEFINES) -pipe
...
CPPFLAGS = $(ARCHINCLUDES) $(ARCHDEFINES) $(EXTRADEFINES)

would change as follows:

CFLAGS = $(ARCHCFLAGS) $(ARCHWARNINGS) $(ARCHOPTIMIZATION) $(ARCHCPUFLAGS) $(ARCHINCLUDES) $(ARCHDEFINES) $(EXTRAFLAGS) -pipe
...
CXXFLAGS = $(ARCHCXXFLAGS) $(ARCHWARNINGSXX) $(ARCHOPTIMIZATION) $(ARCHCPUFLAGS) $(ARCHXXINCLUDES) $(ARCHDEFINES) $(EXTRAFLAGS) -pipe
...
CPPFLAGS = $(ARCHINCLUDES) $(ARCHDEFINES) $(EXTRAFLAGS)

See git commit # 459ad9937377a42785692098ff0d73baaa9551e6 in the main NuttX repository.

If you forget to do this, memory allocations on the heap probably won't work and your user tasks won't start.

To see why, tools/Config.mk assigns a value to KDEFINE such that the preprocessor symbol __KERNEL__ will be defined when certain source files are compiled. KDEFINE is passed to nested invocations of 'make' as EXTRAFLAGS. If your board's scripts/Make.defs still attempts to use EXTRADEFINES, the preprocessor symbol __KERNEL__ will not be defined in some of the places that it should be. Suppose you're building a FLAT build. In this case, include/nuttx/mm/mm.h will not define MM_KERNEL_USRHEAP_INIT like it should, which will cause nx_start.c not to call up_allocate_heap() at startup. Therefore, any attempt to allocate memory on the heap will fail.

Rename src/Makefile to src/Make.defs and Modify

This item pertains only to custom boards that are developed in-tree, meaning under the NuttX boards/ subdirectory. Out-of-tree boards are not affected.

If your custom board directory is in-tree and in a board family that uses a 'boards/ARCH/FAMILY/common' directory (such as boards/arm/stm32/common, boards/arm/cxd56xx/common, etc), then you'll need to make two minor changes to your custom board's src/Makefile:

(1) Rename it from src/Makefile to src/Make.defs, and

(2) Near the end of that file, replace this line, which usually appears at the end:

include $(TOPDIR)/boards/Board.mk

with these three lines:

DEPPATH += --dep-path board
VPATH += :board
CFLAGS += $(shell $(INCDIR) $(INCDIROPT) "$(CC)" $(TOPDIR)$(DELIM)arch$(DELIM)$(CONFIG_ARCH)$(DELIM)src$(DELIM)board$(DELIM)board)

See git commit # 6ca46520df38854bf660f9be54957cceede39ded in the main NuttX repository.

If you forget to do this, 'make' will report an error, "no rule to make libboard.a," and the build will fail.

Rename WINTOOL to CONFIG_CYGWIN_WINTOOL

In your custom board's scripts/Make.defs file, rename any instances of WINTOOL to CONFIG_CYGWIN_WINTOOL.

For example, change this line:

ifeq ($(WINTOOL),y)

to this:

ifeq ($(CONFIG_CYGWIN_WINTOOL),y)

See git commit # bd656888f26c92e8832f0e76b395a5ece7704530 in the main NuttX repository.

Remove INCDIROPT

In your custom board's src/Make.defs file, remove INCDIROPT from CFLAGS.

For example, change this line:

CFLAGS += $(shell $(INCDIR) $(INCDIROPT) "$(CC)" $(TOPDIR)$(DELIM)arch$(DELIM)$(CONFIG_ARCH)$(DELIM)src$(DELIM)board$(DELIM)board)

to this:

CFLAGS += $(shell $(INCDIR) "$(CC)" $(TOPDIR)$(DELIM)arch$(DELIM)$(CONFIG_ARCH)$(DELIM)src$(DELIM)board$(DELIM)board)

This option, which resolves to -w when CONFIG_CYGWIN_WINTOOL is configured, is now appended to INCDIR in tools/Config.mk.

See git commit # 5eae32577e5d5226e5d3027c169eeb369f83f77d in the main NuttX repository.

Remove Unnecessary Variables

In your custom board's scripts/Make.defs file, It is no longer necessary to define the following variables unless your build requires that you assign special values to them:

• DIRLINK
• DIRUNLINK
• MKDEP
• ASMEXT
• OBJEXT
• LIBEXT
• EXEEXT

These variables have been refactored into tools/Config.mk.

See these git commits in the main NuttX repository:

• 9ec9431706fd0eb7c4c4410d84dafff68ff31366 (DIRLINK and DIRUNLINK)
• 8b42ee421a41214093c0238e479d73a1099b0e82 (MKDEP)
• 567962bd6263bf8809fb63c739f6ec668c69c416 (ASMEXT, OBJEXT, LIBEXT, EXEEXT)

Change ${TOPDIR} to $(TOPDIR)

In your custom board's scripts/Make.defs file, it is recommended to change ${TOPDIR} to $(TOPDIR) for consistency (change curly braces to parenthesis).

See git commit # 7faf3c0254bb63af89f9eb59beefacb4cba26dd9 in the main NuttX repository.

Remove Workaround For Missing $(TOPDIR)/Make.defs

In src/Make.defs or src/Makefile for your custom board or custom apps, the workaround for missing $(TOPDIR)/.config and/or $(TOPDIR)/Make.defs is no longer needed. To remove the workaround, delete the minus sign in front of include .config. This is now handled in the main Makefile and, if those files are missing, will print an error message with hint to run tools/configure.sh <target>.

Change this line, located near the top of the file:

-include $(TOPDIR)/Make.defs

to this:

include $(TOPDIR)/Make.defs

See git commit # 1a95cce1a3c3ed8b04d1d86b7bd744352cca45a2 in the main NuttX repository, and git commit # ead498a7883a654b1d542da94a5fab3ce163361e in the apps repository.

Simplify ARCHINCLUDES and ARCHXXINCLUDES

In your custom board's scripts/Make.defs, ARCHINCLUDES and ARCHXXINCLUDES can be defined without maintaining two different versions conditioned upon CONFIG_CYGWIN_WINTOOL (renamed from WINTOOL). Replace syntax similar to the following:

ifeq ($(CONFIG_CYGWIN_WINTOOL),y)
# Windows-native toolchains
  ARCHINCLUDES = -I. -isystem "${shell cygpath -w $(TOPDIR)$(DELIM)include}"
  ARCHXXINCLUDES = -I. -isystem "${shell cygpath -w $(TOPDIR)$(DELIM)include}" -isystem "${shell cygpath -w $(TOPDIR)$(DELIM)include$(DELIM)cxx}"
else
# Linux/Cygwin-native toolchain
  ARCHINCLUDES = -I. -isystem $(TOPDIR)$(DELIM)include
  ARCHXXINCLUDES = -I. -isystem $(TOPDIR)$(DELIM)include -isystem $(TOPDIR)$(DELIM)include$(DELIM)cxx
endif

with syntax similar towith these three lines:

DEPPATHARCHINCLUDES += --dep-path board
VPATH += :board
CFLAGS ${shell $(INCDIR) -s "$(CC)" $(TOPDIR)$(DELIM)include}
ARCHXXINCLUDES += ${shell $(INCDIR) -s "$(CC)" $(TOPDIR)$(DELIM)include}
ARCHXXINCLUDES += $({shell $(INCDIR) $(INCDIROPT)) -s "$(CC)" $(TOPDIR)$(DELIM)arch$(DELIM)$(CONFIG_ARCH)$(DELIM)src$(DELIM)board$(DELIM)board)include$(DELIM)cxx}

INCDIR is defined in tools/Config.mk and resolves to a shell script or batch file that constructs the appropriate command line argument string to specify include directories for your compiler.

See git commit # 7e5b0f81e93c7e879ce8434d57e8bf4e2319c1c0 See git commit # 6ca46520df38854bf660f9be54957cceede39ded in the main NuttX repository.

If you forget to do this, 'make' will report an error, "no rule to make libboard.a," and the build will fail.

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Simplify Board Directory Handling With BOARD_DIR

In your custom board's scripts/Make.defs file, rename any instances of WINTOOL to CONFIG_CYGWIN_WINTOOL. or Makefile, when setting up build variables containing paths inside your board directory, a new variable BOARD_DIR has been introduced that simplifies the syntax:

Replace syntax like thisFor example, change this line:

ifeq ($(WINTOOL),y)

$(TOPDIR)$(DELIM)boards$(DELIM)$(CONFIG_ARCH)$(DELIM)$(CONFIG_ARCH_CHIP)$(DELIM)$(CONFIG_ARCH_BOARD)

with this variableto this:

ifeq ($(CONFIGBOARD_CYGWIN_WINTOOL),y)

See git commit # bd656888f26c92e8832f0e76b395a5ece7704530 in the main NuttX repository.

Remove INCDIROPT

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DIR)

For example, change this line:

CFLAGSARCHSCRIPT += $(shell -T$(TOPDIR)$(INCDIRDELIM) $boards$(INCDIROPTDELIM) "$(CCCONFIG_ARCH)" $(TOPDIRDELIM)$(DELIM)arch$CONFIG_ARCH_CHIP)$(DELIM)$(CONFIG_ARCH_BOARD)$(DELIM)src$scripts$(DELIM)board$$(DELIM)boardLDSCRIPT)

to this much simpler syntax:

CFLAGS += $(shell $(INCDIR) "$(CC)" $(TOPDIRARCHSCRIPT = -T$(BOARD_DIR)$(DELIM)arch$scripts$(DELIM)$(CONFIG_ARCH)$(DELIM)src$(DELIM)board$(DELIM)board)
LDSCRIPT)

You may find the old syntax being used for variables like ARCHSCRIPT, LDELFFLAGS, LINKCMDTEMPLATE, SCRIPTDIR, USER_LDSCRIPT, or others.

BOARD_DIR is defined in This option, which resolves to -w when CONFIG_CYGWIN_WINTOOL is configured, is now appended to INCDIR in tools/Config.mk.

See git commit # 5eae32577e5d5226e5d3027c169eeb369f83f77d e83c1400b65c65cbdf59c5abcf2ae368f540faef in the main NuttX repository.

Remove Unnecessary Variables

In your custom board's scripts/Make.defs file, It is no longer necessary to define the following variables unless your build requires that you assign special values to them:

• DIRLINK
• DIRUNLINK
• MKDEP
• ASMEXT
• OBJEXT
• LIBEXT
• EXEEXT

These variables have been refactored into tools/Config.mk.

See these git commits in the main NuttX repository:

• 9ec9431706fd0eb7c4c4410d84dafff68ff31366 (DIRLINK and DIRUNLINK)
• 8b42ee421a41214093c0238e479d73a1099b0e82 (MKDEP)
• 567962bd6263bf8809fb63c739f6ec668c69c416 (ASMEXT, OBJEXT, LIBEXT, EXEEXT)

Change ${TOPDIR} to $(TOPDIR)

In your custom board's scripts/Make.defs file, it is recommended to change ${TOPDIR} to $(TOPDIR) for consistency (change curly braces to parenthesis).

See git commit # 7faf3c0254bb63af89f9eb59beefacb4cba26dd9 in the main NuttX repository.

Remove Workaround For Missing $(TOPDIR)/Make.defs

In your custom board's src/Make.defs or src/Makefile, remove the workaround for missing .config/Make.defs by removing the minus sign in front of include .config. This is not handled in the main Makefile and will print an error message with hint to run tools/configure.sh <target>.

Change this line, located near the top of the file:

-include $(TOPDIR)/Make.defs

to this:

include $(TOPDIR)/Make.defs

See git commit # 1a95cce1a3c3ed8b04d1d86b7bd744352cca45a2 in the main NuttX repository.

Known Problems In This Release

More Information

How to Download

How to Clone Git Repository

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NuttX repository.

Known Problems In This Release

More Information

How to Download

Release artifacts for all current and past NuttX releases can be downloaded at:

• https://nuttx.apache.org/download/

How to Clone the Git Repository

The Apache NuttX project uses Git SCM as its version control system.

There are two primary repositories:

• nuttx - The real time operating system itself.
• apps - Optional applications and example programs for the operating system. You can use this repository or make your own custom one.

The main "Single Source of Truth" repositories are hosted by the ASF:

• https://gitbox.apache.org/repos/asf?p=incubator-nuttx.git
• https://gitbox.apache.org/repos/asf?p=incubator-nuttx-apps.git

These are synchronized with repositories hosted at GitHub:

• https://github.com/apache/incubator-nuttx/
• https://github.com/apache/incubator-nuttx-apps/

How to Contact the Community

The main forum for project communication, to ask a question, get involved, or contribute to NuttX, is our mailing list, dev@nuttx.apache.org. The list is publicly archived and searchable at https://lists.apache.org/list.html?dev@nuttx.apache.org. For more information, see NuttX Community.

Enthusiastic Contributors Welcome!

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