| Message ID | 20200731075953.14416-4-Sergey.Semin@baikalelectronics.ru (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | spi: dw-dma: Add max SG entries burst capability support | expand |
On Fri, Jul 31, 2020 at 10:59:48AM +0300, Serge Semin wrote: > 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 let's move the DMA slave > channels src/dst burst lengths, address and address width configuration to > the DMA setup stage. While at it make sure the return value of the > dmaengine_slave_config() method is checked. 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. ... > + if (!xfer->rx_buf) > + return NULL; ... > + if (xfer->rx_buf) { > + } This looks like a separate change to drop one of them and not hide in the next patch.
On Fri, Jul 31, 2020 at 12:16:38PM +0300, Andy Shevchenko wrote: > On Fri, Jul 31, 2020 at 10:59:48AM +0300, Serge Semin wrote: > > 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 let's move the DMA slave > > channels src/dst burst lengths, address and address width configuration to > > the DMA setup stage. While at it make sure the return value of the > > dmaengine_slave_config() method is checked. 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. > > ... > Part 1: > > + if (!xfer->rx_buf) > > + return NULL; > > ... > Part 2: > > + if (xfer->rx_buf) { > > > + } > > This looks like a separate change to drop one of them and not hide in the next patch. Both of these changes are a part of the single alteration introduced to detach two methods from each other: dw_spi_dma_{config,prepare}_{rx,tx}(). Part 1 is a statement, which belongs to the method dw_spi_dma_prepare_rx() and is left there after dw_spi_dma_config_rx() has been detached from it. Part 2 is a logical part, which must be presented in dw_spi_dma_setup() since we don't need to configure the Rx DMA channel if rx_buf isn't specified. Please, read more carefully the commit log. I didn't introduce anything other than the changes described there. -Sergey > > -- > With Best Regards, > Andy Shevchenko > >
diff --git a/drivers/spi/spi-dw-dma.c b/drivers/spi/spi-dw-dma.c index ec721af61663..56496b659d62 100644 --- a/drivers/spi/spi-dw-dma.c +++ b/drivers/spi/spi-dw-dma.c @@ -257,11 +257,9 @@ 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; @@ -271,7 +269,13 @@ 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, @@ -346,14 +350,9 @@ 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; @@ -363,7 +362,16 @@ 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, @@ -382,10 +390,22 @@ 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)
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 let's move the DMA slave channels src/dst burst lengths, address and address width configuration to the DMA setup stage. While at it make sure the return value of the dmaengine_slave_config() method is checked. 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> --- drivers/spi/spi-dw-dma.c | 42 +++++++++++++++++++++++++++++----------- 1 file changed, 31 insertions(+), 11 deletions(-)