a5431319bb
Submitting an asynchronous transfer refused any buffer needing a cache line stand-in, and that test also refuses every buffer whose length is not a whole number of cache lines, which an interrupt transfer's rarely is: a HID keyboard reads eight bytes. Every submission returned -EFAULT before a descriptor was written, and a class driver resubmitting from its completion callback never sees a second chance. The refusal existed because the copy out of a stand-in is done by the blocked caller, and an asynchronous transfer has none. The work queue thread handling the completion will do: a buffer given to DRVR_ASYNCH comes from DRVR_ALLOC, so it is kernel memory reachable from any thread. Use the same stand-in machinery as every other transfer and finish the DMA in the completion, just before the callback. A cancelled transfer returns its stand-in on cancellation. The callback also moves outside the spinlock. It is class driver code that queues work and takes its own locks, and it may now free a stand-in. Whether a completion is synchronous is still decided under the lock, since a posted waiter may be carrying a new transfer immediately. The asynchronous setup now records the requested length, as the synchronous setup does. The byte count handed to the callback is worked out from it and the residue, and was previously whatever the endpoint held from an earlier transfer. Assisted-by: Claude:claude-opus-5 Signed-off-by: Justin Hammond <justin@dynam.ac> |
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| arch | ||
| audio | ||
| binfmt | ||
| boards | ||
| cmake | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| dummy | ||
| fs | ||
| graphics | ||
| include | ||
| libs | ||
| mm | ||
| net | ||
| openamp | ||
| pass1 | ||
| sched | ||
| syscall | ||
| tools | ||
| video | ||
| wireless | ||
| .asf.yaml | ||
| .codespell-ignore-lines | ||
| .codespellrc | ||
| .editorconfig | ||
| .gitignore | ||
| .gitmessage | ||
| .pre-commit-config.yaml | ||
| .yamllint | ||
| AUTHORS | ||
| CMakeLists.txt | ||
| CONTRIBUTING.md | ||
| INVIOLABLES.md | ||
| Kconfig | ||
| LICENSE | ||
| Makefile | ||
| NOTICE | ||
| README.md | ||
| ReleaseNotes | ||
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.