Fix a potential deadlock in the DMA driver. DMA completion callbacks
may immediately submit another transfer, for example:
imx9_dmaterminate()
-> imx9_dma_txcallback()
-> imx9_dma_txavailable()
-> uart_xmitchars_dma()
-> imx9_dma_send()
-> imx9_dmach_stop()
-> imx9_dmaterminate()
Resulting dmaterminate to take the same spinlock again. Fix this by moving
the spin_unlock_irqrestore_nopreempt before calling the callback. It is not
necessary to keep dma channel locked during the callback; the channel is
already free at this point.
This doesn't directly affect arch/arm/imx9 (the cortex-m version) because
it is not SMP (the spinlock is reduced to blocking irqs), but it is worth
fixing at the same to keep drivers in sync.
Signed-off-by: Jukka Laitinen <jukka.laitinen@tii.ae>
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| 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()).
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