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spi: dw-dma: Configure the DMA channels in dma_setup

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Mainly this is a preparation patch before adding one-by-one DMA SG entries
transmission. But logically the Tx and Rx DMA channels setup should be
performed in the dma_setup() callback anyway. So we'll move the DMA slave
channels src/dst burst lengths, address and address width configuration
from the Tx/Rx channels preparation methods to the dedicated functions and
then make sure it's called at the DMA setup stage.

Note we now make sure the return value of the dmaengine_slave_config()
method doesn't indicate an error. It has been unnecessary in case if Dw
DMAC is utilized as a DMA engine, since its device_config() callback
always returns zero (though it might change in future). But since DW APB
SSI driver now supports any DMA back-end we must make sure the DMA device
configuration has been successful before proceeding with further setups.

Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Link: https://lore.kernel.org/r/20200920112322.24585-4-Sergey.Semin@baikalelectronics.ru
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Serge Semin 2020-09-20 14:23:14 +03:00 committed by Mark Brown
parent 7ef30385b0
commit a874d811f0
No known key found for this signature in database
GPG key ID: 24D68B725D5487D0
1 changed files with 31 additions and 11 deletions
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42
drivers/spi/spi-dw-dma.c
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@ -256,11 +256,9 @@ static void dw_spi_dma_tx_done(void *arg)
complete(&dws->dma_completion);
}
static struct dma_async_tx_descriptor *
dw_spi_dma_prepare_tx(struct dw_spi *dws, struct spi_transfer *xfer)
static int dw_spi_dma_config_tx(struct dw_spi *dws)
{
struct dma_slave_config txconf;
struct dma_async_tx_descriptor *txdesc;
memset(&txconf, 0, sizeof(txconf));
txconf.direction = DMA_MEM_TO_DEV;
@ -270,7 +268,13 @@ dw_spi_dma_prepare_tx(struct dw_spi *dws, struct spi_transfer *xfer)
txconf.dst_addr_width = dw_spi_dma_convert_width(dws->n_bytes);
txconf.device_fc = false;
dmaengine_slave_config(dws->txchan, &txconf);
return dmaengine_slave_config(dws->txchan, &txconf);
}
static struct dma_async_tx_descriptor *
dw_spi_dma_prepare_tx(struct dw_spi *dws, struct spi_transfer *xfer)
{
struct dma_async_tx_descriptor *txdesc;
txdesc = dmaengine_prep_slave_sg(dws->txchan,
xfer->tx_sg.sgl,
@ -345,14 +349,9 @@ static void dw_spi_dma_rx_done(void *arg)
complete(&dws->dma_completion);
}
static struct dma_async_tx_descriptor *dw_spi_dma_prepare_rx(struct dw_spi *dws,
struct spi_transfer *xfer)
static int dw_spi_dma_config_rx(struct dw_spi *dws)
{
struct dma_slave_config rxconf;
struct dma_async_tx_descriptor *rxdesc;
if (!xfer->rx_buf)
return NULL;
memset(&rxconf, 0, sizeof(rxconf));
rxconf.direction = DMA_DEV_TO_MEM;
@ -362,7 +361,16 @@ static struct dma_async_tx_descriptor *dw_spi_dma_prepare_rx(struct dw_spi *dws,
rxconf.src_addr_width = dw_spi_dma_convert_width(dws->n_bytes);
rxconf.device_fc = false;
dmaengine_slave_config(dws->rxchan, &rxconf);
return dmaengine_slave_config(dws->rxchan, &rxconf);
}
static struct dma_async_tx_descriptor *dw_spi_dma_prepare_rx(struct dw_spi *dws,
struct spi_transfer *xfer)
{
struct dma_async_tx_descriptor *rxdesc;
if (!xfer->rx_buf)
return NULL;
rxdesc = dmaengine_prep_slave_sg(dws->rxchan,
xfer->rx_sg.sgl,
@ -381,10 +389,22 @@ static struct dma_async_tx_descriptor *dw_spi_dma_prepare_rx(struct dw_spi *dws,
static int dw_spi_dma_setup(struct dw_spi *dws, struct spi_transfer *xfer)
{
u16 imr, dma_ctrl;
int ret;
if (!xfer->tx_buf)
return -EINVAL;
/* Setup DMA channels */
ret = dw_spi_dma_config_tx(dws);
if (ret)
return ret;
if (xfer->rx_buf) {
ret = dw_spi_dma_config_rx(dws);
if (ret)
return ret;
}
/* Set the DMA handshaking interface */
dma_ctrl = SPI_DMA_TDMAE;
if (xfer->rx_buf)