| Message ID | 20180510070048.9035-1-m.szyprowski@samsung.com |
|---|---|
| State | New |
| Headers | show |
| Series | serial: samsung: check DMA channel capabilities before using DMA mode | expand |
On Thu, May 10, 2018 at 09:00:48AM +0200, Marek Szyprowski wrote: > DMA engine driver might not always provide all the features needed by > serial driver to properly operate in DMA mode, so check that before > selecting DMA mode. > > Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> > --- > drivers/tty/serial/samsung.c | 15 +++++++++++++++ > 1 file changed, 15 insertions(+) > > diff --git a/drivers/tty/serial/samsung.c b/drivers/tty/serial/samsung.c > index 64e96926f1ad..334b53c6eb14 100644 > --- a/drivers/tty/serial/samsung.c > +++ b/drivers/tty/serial/samsung.c > @@ -856,6 +856,7 @@ static void s3c24xx_serial_break_ctl(struct uart_port *port, int break_state) > static int s3c24xx_serial_request_dma(struct s3c24xx_uart_port *p) > { > struct s3c24xx_uart_dma *dma = p->dma; > + struct dma_slave_caps dma_caps; > int ret; > > /* Default slave configuration parameters */ > @@ -874,6 +875,13 @@ static int s3c24xx_serial_request_dma(struct s3c24xx_uart_port *p) > if (IS_ERR(dma->rx_chan)) > return PTR_ERR(dma->rx_chan); > > + ret = dma_get_slave_caps(dma->rx_chan, &dma_caps); > + if (ret < 0 || > + dma_caps.residue_granularity < DMA_RESIDUE_GRANULARITY_BURST) { Let's print here reason of DMA setup failure? Later only generic message about not using DMA would be shown. The same in second path. Best regards, Krzysztof > + ret = -ENODEV; > + goto err_release_rx; > + } > + > dmaengine_slave_config(dma->rx_chan, &dma->rx_conf); > > dma->tx_chan = dma_request_chan(p->port.dev, "tx"); > @@ -882,6 +890,13 @@ static int s3c24xx_serial_request_dma(struct s3c24xx_uart_port *p) > goto err_release_rx; > } > > + ret = dma_get_slave_caps(dma->tx_chan, &dma_caps); > + if (ret < 0 || > + dma_caps.residue_granularity < DMA_RESIDUE_GRANULARITY_BURST) { > + ret = -ENODEV; > + goto err_release_tx; > + } > + > dmaengine_slave_config(dma->tx_chan, &dma->tx_conf); > > /* RX buffer */ > -- > 2.17.0 > -- To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/tty/serial/samsung.c b/drivers/tty/serial/samsung.c index 64e96926f1ad..334b53c6eb14 100644 --- a/drivers/tty/serial/samsung.c +++ b/drivers/tty/serial/samsung.c @@ -856,6 +856,7 @@ static void s3c24xx_serial_break_ctl(struct uart_port *port, int break_state) static int s3c24xx_serial_request_dma(struct s3c24xx_uart_port *p) { struct s3c24xx_uart_dma *dma = p->dma; + struct dma_slave_caps dma_caps; int ret; /* Default slave configuration parameters */ @@ -874,6 +875,13 @@ static int s3c24xx_serial_request_dma(struct s3c24xx_uart_port *p) if (IS_ERR(dma->rx_chan)) return PTR_ERR(dma->rx_chan); + ret = dma_get_slave_caps(dma->rx_chan, &dma_caps); + if (ret < 0 || + dma_caps.residue_granularity < DMA_RESIDUE_GRANULARITY_BURST) { + ret = -ENODEV; + goto err_release_rx; + } + dmaengine_slave_config(dma->rx_chan, &dma->rx_conf); dma->tx_chan = dma_request_chan(p->port.dev, "tx"); @@ -882,6 +890,13 @@ static int s3c24xx_serial_request_dma(struct s3c24xx_uart_port *p) goto err_release_rx; } + ret = dma_get_slave_caps(dma->tx_chan, &dma_caps); + if (ret < 0 || + dma_caps.residue_granularity < DMA_RESIDUE_GRANULARITY_BURST) { + ret = -ENODEV; + goto err_release_tx; + } + dmaengine_slave_config(dma->tx_chan, &dma->tx_conf); /* RX buffer */
DMA engine driver might not always provide all the features needed by serial driver to properly operate in DMA mode, so check that before selecting DMA mode. Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> --- drivers/tty/serial/samsung.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) -- 2.17.0 -- To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html