Unverified Commit ab7a4d75 authored by Serge Semin's avatar Serge Semin Committed by Mark Brown
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spi: dw-dma: Move DMA transfers submission to the channels prep methods 



Indeed we can freely move the dmaengine_submit() method invocation and the
Tx and Rx busy flag setting into the DMA Tx/Rx prepare methods. Since the
Tx/Rx preparation method is now mainly used for the DMA transfers
submission, here we suggest to rename it to have the _submit_{r,t}x suffix
instead.

By having this alteration applied first we implement another code
preparation before adding the one-by-one DMA SG entries transmission,
second we now have the dma_async_tx_descriptor descriptor used locally
only in the new DMA transfers submission methods (this will be cleaned up
a bit later), third we make the generic transfer method more readable,
where now the functionality of submission, execution and wait procedures
is transparently split up instead of having a preparation, intermixed
submission/execution and wait procedures.

Signed-off-by: default avatarSerge Semin <Sergey.Semin@baikalelectronics.ru>
Link: https://lore.kernel.org/r/20200920112322.24585-6-Sergey.Semin@baikalelectronics.ru


Signed-off-by: default avatarMark Brown <broonie@kernel.org>
parent be3034d9

drivers/spi/spi-dw-dma.c

+12 −10
Original line number Diff line number Diff line
@@ -272,7 +272,7 @@ static int dw_spi_dma_config_tx(struct dw_spi *dws) 
}



static struct dma_async_tx_descriptor *

dw_spi_dma_prepare_tx(struct dw_spi *dws, struct spi_transfer *xfer)

dw_spi_dma_submit_tx(struct dw_spi *dws, struct spi_transfer *xfer)

{

	struct dma_async_tx_descriptor *txdesc;
@@ -287,6 +287,9 @@ dw_spi_dma_prepare_tx(struct dw_spi *dws, struct spi_transfer *xfer) 
	txdesc->callback = dw_spi_dma_tx_done;

	txdesc->callback_param = dws;



	dmaengine_submit(txdesc);

	set_bit(TX_BUSY, &dws->dma_chan_busy);



	return txdesc;

}
@@ -364,7 +367,7 @@ static int dw_spi_dma_config_rx(struct dw_spi *dws) 
	return dmaengine_slave_config(dws->rxchan, &rxconf);

}



static struct dma_async_tx_descriptor *dw_spi_dma_prepare_rx(struct dw_spi *dws,

static struct dma_async_tx_descriptor *dw_spi_dma_submit_rx(struct dw_spi *dws,

		struct spi_transfer *xfer)

{

	struct dma_async_tx_descriptor *rxdesc;
@@ -380,6 +383,9 @@ static struct dma_async_tx_descriptor *dw_spi_dma_prepare_rx(struct dw_spi *dws, 
	rxdesc->callback = dw_spi_dma_rx_done;

	rxdesc->callback_param = dws;



	dmaengine_submit(rxdesc);

	set_bit(RX_BUSY, &dws->dma_chan_busy);



	return rxdesc;

}
@@ -426,25 +432,21 @@ static int dw_spi_dma_transfer(struct dw_spi *dws, struct spi_transfer *xfer) 
	struct dma_async_tx_descriptor *txdesc, *rxdesc;

	int ret;



	/* Prepare the TX dma transfer */

	txdesc = dw_spi_dma_prepare_tx(dws, xfer);

	/* Submit the DMA Tx transfer */

	txdesc = dw_spi_dma_submit_tx(dws, xfer);

	if (!txdesc)

		return -EINVAL;



	/* Prepare the RX dma transfer */

	/* Submit the DMA Rx transfer if required */

	if (xfer->rx_buf) {

		rxdesc = dw_spi_dma_prepare_rx(dws, xfer);

		rxdesc = dw_spi_dma_submit_rx(dws, xfer);

		if (!rxdesc)

			return -EINVAL;



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

		set_bit(RX_BUSY, &dws->dma_chan_busy);

		dmaengine_submit(rxdesc);

		dma_async_issue_pending(dws->rxchan);

	}



	set_bit(TX_BUSY, &dws->dma_chan_busy);

	dmaengine_submit(txdesc);

	dma_async_issue_pending(dws->txchan);



	ret = dw_spi_dma_wait(dws, xfer);