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Ricard Rosson cfeca506f8 rp2040/rp23xx: implement stall queueing and GET STATUS responses
Two device-controller defects that break standard host error recovery,
found while root-causing why macOS never mounts a NuttX mass-storage
function (full analysis and host traces in apache/nuttx#19435):

1. epsubmit() aborted (-EBUSY) any IN request submitted while the
   endpoint was halted.  The mass storage class halts bulk-IN for a
   failed device-to-host command (BOT-legal) and then submits the CSW;
   the CSW was dropped on the floor, so after the host's Clear-Halt the
   endpoint NAKed forever and the host timed out (macOS: 30 s, then a
   Bulk-Only-reset/device-reset spiral until it disables the port).
   This is exactly the race documented for years in the usbmsc_scsi.c
   header (David Hewson's analysis); the USBMSC_STALL_RACEWAR sleep
   workaround only survives hosts that clear the halt within 100 ms --
   Linux does, macOS does not, which is why Linux testing never saw it.

   Implement the stall-queueing contract instead: requests submitted
   while an endpoint is halted are queued without arming the hardware
   (arming rewrites the buffer control word and would silently clear
   the STALL bit); a halt terminates any in-flight IN transfer (its
   hardware buffer is disarmed by the STALL write and would never
   complete); clearing the halt resets the data toggle and re-arms the
   head of the queue; stale buffer completions latched for transfers
   aborted by a halt are ignored.  RP2040/RP23XX now select
   ARCH_USBDEV_STALLQUEUE, which also retires the RACEWAR's two 100 ms
   sleeps per failed command.

2. The USB_REQ_GETSTATUS handler in ep0setup() validated the request
   but never queued the two-byte response, for all three recipients
   (device/interface/endpoint), so EP0 NAKed the host's data stage
   forever and every GET STATUS timed out.  macOS issues GetPipeStatus
   = GET STATUS(endpoint) on a halted pipe before running Bulk-Only
   reset recovery and hit this on every probe; lsusb -v's device-status
   query hangs on it as well.  Send the response: endpoint recipient
   reports the halt bit, device recipient reports self-powered,
   interface reports zeros; the status stage is armed by handle_zlp()
   exactly as for class-dispatched IN transfers.

Validated on RP2350 silicon (Raspberry Pi Pico 2 W, composite
CDC-ACM + CDC-NCM + USBMSC): pre-fix, a raw-usbfs replay of macOS's
sequence and timing reproduced both defects deterministically (CSW read
ETIMEDOUT after a delayed clear-halt; all GET STATUS variants
ETIMEDOUT).  Post-fix: the CSW survives the halt and is delivered after
Clear-Halt with correct tag/status/residue across a post-stall delay
sweep of 0-1000 ms; all GET STATUS variants answer immediately with
correct halt reporting; no regressions in the exact-length SCSI suite,
Bulk-Only reset, FAT mount and full reads, CDC-NCM/ACM, or warm
reboots; and macOS now mounts the volume (together with the companion
usbmsc fixes).  The rp2040 driver shares the code and receives the
identical fix (build-tested).

Assisted-by: Claude (Anthropic Claude Code)
Signed-off-by: Ricard Rosson <ricard@groundbits.com>
2026-07-28 12:40:25 +02:00
.github build(deps): bump actions/setup-python from 6 to 7 2026-07-27 13:34:36 -04:00
arch rp2040/rp23xx: implement stall queueing and GET STATUS responses 2026-07-28 12:40:25 +02:00
audio drivers/efuse/efuse: Drivers Registered With World Write Permissions(Part 1) 2026-07-13 12:08:01 +02:00
binfmt elf:use elf symbol to parse attribute 2026-07-15 12:24:44 -03:00
boards boards/rp23xx: add missing rp23xx_st7735.c LCD board glue 2026-07-28 10:16:12 +08:00
cmake cmake: Omit default priority ELF symbol. 2026-07-27 14:30:42 +08:00
crypto crypto: add CRYPTO_AES_CTR_SSH variant (128-bit big-endian counter) 2026-07-16 15:42:10 +08:00
Documentation documentation: mention PIO4IOE IO Expander 2026-07-28 10:18:01 +08:00
drivers drivers/usbdev/cdcncm: send TX immediately, not after a tick-quantized delay 2026-07-28 12:39:39 +02:00
dummy build: add initial cmake build system 2023-07-08 13:50:48 +08:00
fs fs/vfs: Add ioctldir for volume ioctls via the mountpoint directory. 2026-07-25 07:28:22 -03:00
graphics drivers/: Multiple Drivers Are Registered With World Writable - Part 2 2026-07-15 15:27:28 +08:00
include drives/ioexpander: add support to PI4IOE IO Expander 2026-07-28 10:18:01 +08:00
libs libc/time: Fix POSIX timezone string parsing. 2026-07-25 19:54:18 +08:00
mm arch/mips: Add basic support for MIPS Creator CI20 board 2026-07-15 08:02:55 -03:00
net net/sixlowpan: Fix protosize to 16-bit 2026-07-28 10:19:05 +08:00
openamp openamp: fix CMake dcache option 2026-05-10 15:03:24 +02:00
pass1 Makefile: Remove make depend files by make distclean 2026-02-16 16:27:57 +01:00
sched sched/sched_critmonitor: remove duplicate preemption start block 2026-07-28 16:04:50 +08:00
syscall syscall: fcntl param3 type to uintptr_t 2026-04-27 12:01:55 -03:00
tools tools/nxstyle: add a script to check a whole tree at once 2026-07-28 02:43:24 +08:00
video video: fix EDID standard timing decode 2026-07-17 15:00:50 -03:00
wireless drivers/: Multiple Drivers Are Registered With World Writable - Part 2 2026-07-15 15:27:28 +08:00
.asf.yaml github: master branch protection tune. 2025-05-07 18:37:13 -05:00
.codespell-ignore-lines arch/arm: Reserve r10 via ARCHCFLAGS and hoist the PIC module flags. 2026-07-24 23:09:08 +08:00
.codespellrc arch/arm/rp23xx: Add hardware TRNG driver for /dev/random. 2026-07-25 15:06:56 +08:00
.editorconfig .editorconfig: fix character encoding property specification 2025-11-28 19:12:13 +08:00
.gitignore git: Specify multiple build directories in .gitignore. 2026-05-20 03:06:58 +08:00
.gitmessage docs/contributing: Add a commit message template 2025-06-03 17:33:24 +08:00
.pre-commit-config.yaml pre-commit: enable codespell checks 2025-05-05 12:34:39 +08:00
.yamllint feat: add a GitHub action to lint the YAML files 2020-12-15 09:52:04 -06:00
AUTHORS AUTHORS: add Eren Terzioglu 2026-05-20 15:17:00 +08:00
CMakeLists.txt cmake: Do not link an executable to detect the compiler. 2026-07-25 22:52:39 +08:00
CONTRIBUTING.md contributing: Add requirement for 'Assisted-by' commit field 2026-07-12 09:42:28 +08:00
INVIOLABLES.md INVIOLABLES.md: Fix a simple alignment and change occurrences of Nuttx 2020-09-03 01:33:05 +08:00
Kconfig sched/misc/assert: Add CONFIG_SCHED_DUMP_TASKS and CONFIG_SCHED_DUMP_STACK 2026-06-09 08:04:54 -04:00
LICENSE libs/libdsp: Add Matrix operations 2026-07-11 14:55:59 -03:00
Makefile !boards: enforce secure ROMFS passwd and TEA key setup 2026-07-09 22:41:11 +08:00
NOTICE Remove the double blank line from source files 2022-02-20 20:10:14 +01:00
README.md ci/testing: Add MemBrowse Integration 2026-06-18 12:07:41 -03:00
ReleaseNotes Documentation: move ReleaseNotes 2023-09-26 20:41:00 +08:00

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Apache NuttX is a real-time operating system (RTOS) with an emphasis on standards compliance and small footprint. Scalable from 8-bit to 64-bit microcontroller environments, the primary governing standards in NuttX are POSIX and ANSI standards. Additional standard APIs from Unix and other common RTOSs (such as VxWorks) are adopted for functionality not available under these standards, or for functionality that is not appropriate for deeply-embedded environments (such as fork()).

For brevity, many parts of the documentation will refer to Apache NuttX as simply NuttX.

Getting Started

First time on NuttX? Read the Getting Started guide! If you don't have a board available, NuttX has its own simulator that you can run on terminal.

Documentation

You can find the current NuttX documentation on the Documentation Page.

Alternatively, you can build the documentation yourself by following the Documentation Build Instructions.

The old NuttX documentation is still available in the Apache wiki.

Supported Boards

NuttX supports a wide variety of platforms. See the full list on the Supported Platforms page.

Contributing

If you wish to contribute to the NuttX project, read the Contributing guidelines for information on Git usage, coding standard, workflow and the NuttX principles.

License

The code in this repository is under either the Apache 2 license, or a license compatible with the Apache 2 license. See the License Page for more information.