STM, SPI DMA 16bit

[paveldedourek-eaton]

I have some doubts regarding implementation of function spi_dma_move_buffers() used in transceive_dma() - spi_ll_stm32.c

This spi_dma_move_buffers() function has 2nd parameter which is length of data (size_t data type).

spi_stm32_dma_rx_load()_ function is called in spi_dma_move_buffers() and second parameter is length of data also (size_t data type).

I do not understand, why there is following equation:

zephyr/drivers/spi/spi_ll_stm32.c

Line 210 in 4c34331

dma_segment_len = len / data->dma_rx.dma_cfg.dest_data_size;

In documentation, you can find, that second parameter is used for block_size = is the number of bytes to be transferred for this block.

When I configured my DMA to cooperate with SPI where frames are 16bit and I wanted to send/receive 6 bytes (3 words) I got accoring to equation 3 bytes to be received (6/2=3). But at the end we are going to transfer 6 bytes.

I have a feeling that something is not implemented correctly, can somebody help me with it who is more experienced with this driver? Thanks!

[erwango]

@FRASTM ^^