Unverified Commit fbb618e1 authored by James Clark's avatar James Clark Committed by Mark Brown
Browse files

spi: spi-fsl-dspi: Use whole page for DMA buffers 



dma_alloc_noncoherent() allocations are backed by a full page anyway, so
use it all.

VF610 devices used to use the full page before commit a957499b
("spi: spi-fsl-dspi: Fix bits-per-word acceleration in DMA mode"), but
others still used the FIFO size. After that commit, all devices used the
FIFO size. Now all devices use the full page.

Signed-off-by: default avatarJames Clark <james.clark@linaro.org>
Reviewed-by: default avatarVladimir Oltean <vladimir.oltean@nxp.com>
Message-ID: <20250902-james-nxp-spi-dma-v6-5-f7aa2c5e56e2@linaro.org>
Signed-off-by: default avatarMark Brown <broonie@kernel.org>
parent 36db0b03

drivers/spi/spi-fsl-dspi.c

+30 −11
Original line number Diff line number Diff line
@@ -331,6 +331,8 @@ struct fsl_dspi_dma { 
	dma_addr_t				rx_dma_phys;

	struct completion			cmd_rx_complete;

	struct dma_async_tx_descriptor		*rx_desc;



	size_t					bufsize;

};



struct fsl_dspi {
@@ -493,6 +495,24 @@ static u32 dspi_pop_tx_pushr(struct fsl_dspi *dspi) 
	return cmd << 16 | data;

}



static size_t dspi_dma_max_datawords(struct fsl_dspi *dspi)

{

	/*

	 * Transfers look like one of these, so we always use a full DMA word

	 * regardless of SPI word size:

	 *

	 * 31              16 15                   0

	 * -----------------------------------------

	 * |   CONTROL WORD  |     16-bit DATA     |

	 * -----------------------------------------

	 * or

	 * -----------------------------------------

	 * |   CONTROL WORD  | UNUSED | 8-bit DATA |

	 * -----------------------------------------

	 */

	return dspi->dma->bufsize / DMA_SLAVE_BUSWIDTH_4_BYTES;

}



static size_t dspi_dma_transfer_size(struct fsl_dspi *dspi)

{

	return dspi->words_in_flight * DMA_SLAVE_BUSWIDTH_4_BYTES;
@@ -620,9 +640,8 @@ static void dspi_dma_xfer(struct fsl_dspi *dspi) 
		/* Figure out operational bits-per-word for this chunk */

		dspi_setup_accel(dspi);



		dspi->words_in_flight = dspi->len / dspi->oper_word_size;

		if (dspi->words_in_flight > dspi->devtype_data->fifo_size)

			dspi->words_in_flight = dspi->devtype_data->fifo_size;

		dspi->words_in_flight = min(dspi->len / dspi->oper_word_size,

					    dspi_dma_max_datawords(dspi));



		message->actual_length += dspi->words_in_flight *

					  dspi->oper_word_size;
@@ -637,7 +656,6 @@ static void dspi_dma_xfer(struct fsl_dspi *dspi) 


static int dspi_request_dma(struct fsl_dspi *dspi, phys_addr_t phy_addr)

{

	int dma_bufsize = dspi->devtype_data->fifo_size * 2;

	struct device *dev = &dspi->pdev->dev;

	struct dma_slave_config cfg;

	struct fsl_dspi_dma *dma;
@@ -657,8 +675,10 @@ static int dspi_request_dma(struct fsl_dspi *dspi, phys_addr_t phy_addr) 
		goto err_tx_channel;

	}



	dma->bufsize = PAGE_SIZE;



	dma->tx_dma_buf = dma_alloc_noncoherent(dma->chan_tx->device->dev,

						dma_bufsize, &dma->tx_dma_phys,

						dma->bufsize, &dma->tx_dma_phys,

						DMA_TO_DEVICE, GFP_KERNEL);

	if (!dma->tx_dma_buf) {

		ret = -ENOMEM;
@@ -666,7 +686,7 @@ static int dspi_request_dma(struct fsl_dspi *dspi, phys_addr_t phy_addr) 
	}



	dma->rx_dma_buf = dma_alloc_noncoherent(dma->chan_rx->device->dev,

						dma_bufsize, &dma->rx_dma_phys,

						dma->bufsize, &dma->rx_dma_phys,

						DMA_FROM_DEVICE, GFP_KERNEL);

	if (!dma->rx_dma_buf) {

		ret = -ENOMEM;
@@ -702,11 +722,11 @@ static int dspi_request_dma(struct fsl_dspi *dspi, phys_addr_t phy_addr) 
	return 0;



err_slave_config:

	dma_free_noncoherent(dma->chan_rx->device->dev, dma_bufsize,

	dma_free_noncoherent(dma->chan_rx->device->dev, dma->bufsize,

			     dma->rx_dma_buf, dma->rx_dma_phys,

			     DMA_FROM_DEVICE);

err_rx_dma_buf:

	dma_free_noncoherent(dma->chan_tx->device->dev, dma_bufsize,

	dma_free_noncoherent(dma->chan_tx->device->dev, dma->bufsize,

			     dma->tx_dma_buf, dma->tx_dma_phys, DMA_TO_DEVICE);

err_tx_dma_buf:

	dma_release_channel(dma->chan_tx);
@@ -721,21 +741,20 @@ static int dspi_request_dma(struct fsl_dspi *dspi, phys_addr_t phy_addr) 


static void dspi_release_dma(struct fsl_dspi *dspi)

{

	int dma_bufsize = dspi->devtype_data->fifo_size * 2;

	struct fsl_dspi_dma *dma = dspi->dma;



	if (!dma)

		return;



	if (dma->chan_tx) {

		dma_free_noncoherent(dma->chan_tx->device->dev, dma_bufsize,

		dma_free_noncoherent(dma->chan_tx->device->dev, dma->bufsize,

				     dma->tx_dma_buf, dma->tx_dma_phys,

				     DMA_TO_DEVICE);

		dma_release_channel(dma->chan_tx);

	}



	if (dma->chan_rx) {

		dma_free_noncoherent(dma->chan_rx->device->dev, dma_bufsize,

		dma_free_noncoherent(dma->chan_rx->device->dev, dma->bufsize,

				     dma->rx_dma_buf, dma->rx_dma_phys,

				     DMA_FROM_DEVICE);

		dma_release_channel(dma->chan_rx);