IDF V6 SPI API issue (IDFGH-17260)

[vladkvit]

Answers checklist.

• I have read the documentation ESP-IDF Programming Guide and the issue is not addressed there.
• I have updated my IDF branch (master or release) to the latest version and checked that the issue is present there.
• I have searched the issue tracker for a similar issue and not found a similar issue.

General issue report

After updating to ESP-IDF v6.0, I am facing an issue with my SPI driver. This issue is a regression - IDF v5.5.2 works fine. The core problem - my SPI driver interfaces with an ADC, I need to read precisely 18 bytes of data, and v6 does not allow reading of amounts not aligned to 4.

I configure my SPI like so:

  void* spi2adc         = heap_caps_malloc(20, MALLOC_CAP_DMA);
  void* adc2spi         = heap_caps_malloc(20, MALLOC_CAP_DMA);

  transDesc = {
      .flags            = SPI_TRANS_DMA_BUFFER_ALIGN_MANUAL,
      .cmd              = 0,
      .addr             = 0,
      .length           = 18 * 8, // in bits.
      .rxlength         = 0, // 0 makes it rxlength set to the value of .length
      .override_freq_hz = 0,
      .user             = nullptr,
      .tx_buffer        = spi2adc,
      .rx_buffer        = adc2spi,
  };

When I call spi_device_polling_start(), I get the following exception:

SPI_TRANS_DMA_BUFFER_ALIGN_MANUAL but RX addr&len not align to 4, or not dma_capable

Note that I allocate a 20-byte buffer, but I just need to read exactly 18 bytes.