8302295dd0
The STM32 DMA NDTR/CNDTR transfer-count register is 16 bits wide on
every STM32 series the in-tree driver supports (IPv1 CNDTR, IPv2
SxNDTR). spi_exchange()'s DMA path forwarded the caller's full
nwords to stm32_dmasetup(), so a single SPI_EXCHANGE() of >= 65536
words silently programmed NDTR to (nwords & 0xffff). When the
truncated count was zero - the typical case for an exact 64 KiB
transfer (flash erase block, FAT cluster, common DMA staging
buffer) - the stream completed instantly with no transfer-complete
interrupt and the caller deadlocked in spi_dmarxwait().
Walk the request in chunks of at most 65535 words inside the
existing DMA branch, reusing the same spi_dma{rx,tx}{setup,start,
wait}() sequence per chunk. Single-descriptor transfers (every
in-tree caller today) are byte-for-byte identical. CONFIG_SPI_TRIGGER
is honored for the first chunk only; subsequent chunks must run
unconditionally because re-arming between chunks of one logical
exchange was never part of the SPI_TRIGGER contract.
Drive-by: rescale priv->buflen-clamped nwords so the DMA
descriptor matches the actually-copied byte count, promote the
spiinfo() format specifier from %d to %zu, and fix two adjacent
comment typos.
See the PR description for reproduction, NSH log and benchmark
numbers (5.12 MB/s, 97.5% of SCK/8 @ 42 MHz on STM32F407 + W25Q128).
Signed-off-by: Jinji Cui <113000688+cjj66619@users.noreply.github.com>
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| audio | ||
| binfmt | ||
| boards | ||
| cmake | ||
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| dummy | ||
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| .asf.yaml | ||
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| Kconfig | ||
| LICENSE | ||
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| 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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