Re: [PATCH v5 4/7] spi: spi-fsl-dspi: Use non-coherent memory for DMA

[Vladimir Oltean]

On Fri, Aug 29, 2025 at 12:46:46PM +0100, James Clark wrote:
> @@ -517,6 +529,7 @@ static void dspi_rx_dma_callback(void *arg)
>  
>  static int dspi_next_xfer_dma_submit(struct fsl_dspi *dspi)
>  {
> +	size_t size = dspi_dma_transfer_size(dspi);
>  	struct device *dev = &dspi->pdev->dev;
>  	struct fsl_dspi_dma *dma = dspi->dma;
>  	int time_left;
> @@ -525,10 +538,9 @@ static int dspi_next_xfer_dma_submit(struct fsl_dspi *dspi)
>  	for (i = 0; i < dspi->words_in_flight; i++)
>  		dspi->dma->tx_dma_buf[i] = dspi_pop_tx_pushr(dspi);
>  
> +	dma_sync_single_for_device(dev, dma->tx_dma_phys, size, DMA_TO_DEVICE);
>  	dma->tx_desc = dmaengine_prep_slave_single(dma->chan_tx,
> -					dma->tx_dma_phys,
> -					dspi->words_in_flight *
> -					DMA_SLAVE_BUSWIDTH_4_BYTES,
> +					dma->tx_dma_phys, size,
>  					DMA_MEM_TO_DEV,
>  					DMA_PREP_INTERRUPT | DMA_CTRL_ACK);

Can you please realign the arguments here to the open parenthesis.

>  	if (!dma->tx_desc) {
> @@ -543,10 +555,10 @@ static int dspi_next_xfer_dma_submit(struct fsl_dspi *dspi)
>  		return -EINVAL;
>  	}
>  
> +	dma_sync_single_for_device(dev, dma->rx_dma_phys, size,
> +				   DMA_FROM_DEVICE);
>  	dma->rx_desc = dmaengine_prep_slave_single(dma->chan_rx,
> -					dma->rx_dma_phys,
> -					dspi->words_in_flight *
> -					DMA_SLAVE_BUSWIDTH_4_BYTES,
> +					dma->rx_dma_phys, size,
>  					DMA_DEV_TO_MEM,
>  					DMA_PREP_INTERRUPT | DMA_CTRL_ACK);

And here.

>  	if (!dma->rx_desc) {