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@xxxxxxxxxxx>
---
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) {
+ 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
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