Unverified Commit be3034d9 authored by Serge Semin's avatar Serge Semin Committed by Mark Brown
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spi: dw-dma: Check rx_buf availability in the xfer method 



Checking rx_buf for being NULL and returning NULL from the Rx-channel
preparation method doesn't let us to distinguish that situation from
errors happening during the Rx SG-list preparation. So it's better to make
sure that the rx_buf not-NULL and full-duplex communication is requested
prior calling the Rx preparation method.

Signed-off-by: default avatarSerge Semin <Sergey.Semin@baikalelectronics.ru>
Link: https://lore.kernel.org/r/20200920112322.24585-5-Sergey.Semin@baikalelectronics.ru


Signed-off-by: default avatarMark Brown <broonie@kernel.org>
parent a874d811

drivers/spi/spi-dw-dma.c

+6 −7
Original line number Diff line number Diff line
@@ -369,9 +369,6 @@ static struct dma_async_tx_descriptor *dw_spi_dma_prepare_rx(struct dw_spi *dws, 
{

	struct dma_async_tx_descriptor *rxdesc;



	if (!xfer->rx_buf)

		return NULL;



	rxdesc = dmaengine_prep_slave_sg(dws->rxchan,

				xfer->rx_sg.sgl,

				xfer->rx_sg.nents,
@@ -435,10 +432,12 @@ static int dw_spi_dma_transfer(struct dw_spi *dws, struct spi_transfer *xfer) 
		return -EINVAL;



	/* Prepare the RX dma transfer */

	if (xfer->rx_buf) {

		rxdesc = dw_spi_dma_prepare_rx(dws, xfer);

		if (!rxdesc)

			return -EINVAL;



		/* rx must be started before tx due to spi instinct */

	if (rxdesc) {

		set_bit(RX_BUSY, &dws->dma_chan_busy);

		dmaengine_submit(rxdesc);

		dma_async_issue_pending(dws->rxchan);
@@ -458,7 +457,7 @@ static int dw_spi_dma_transfer(struct dw_spi *dws, struct spi_transfer *xfer) 
			return ret;

	}



	if (rxdesc && dws->master->cur_msg->status == -EINPROGRESS)

	if (xfer->rx_buf && dws->master->cur_msg->status == -EINPROGRESS)

		ret = dw_spi_dma_wait_rx_done(dws);



	return ret;