From: Muhammad Hamza Farooq <mfarooq@xxxxxxxxxxx>
Occasionally, DMA transaction completes _after_ DMA engine is stopped.
Verify if the transaction has not finished before forcing the engine to
stop and push the data
Signed-off-by: Muhammad Hamza Farooq <mfarooq@xxxxxxxxxxx>
Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
---
v4:
- New.
---
drivers/tty/serial/sh-sci.c | 16 ++++++++++++++++
1 file changed, 16 insertions(+)
diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c
index 9406fe227bc76c96..b1d1ce1986e6c064 100644
--- a/drivers/tty/serial/sh-sci.c
+++ b/drivers/tty/serial/sh-sci.c
@@ -1277,6 +1277,7 @@ static bool filter(struct dma_chan *chan, void *slave)
static void rx_timer_fn(unsigned long arg)
{
struct sci_port *s = (struct sci_port *)arg;
+ struct dma_chan *chan = s->chan_rx;
struct uart_port *port = &s->port;
struct dma_tx_state state;
enum dma_status status;
@@ -1305,6 +1306,21 @@ static void rx_timer_fn(unsigned long arg)
return;
}
+ dmaengine_pause(chan);
+
+ /*
+ * sometimes DMA transfer doesn't stop even if it is stopped and
+ * data keeps on coming until transaction is complete so check
+ * for DMA_COMPLETE again
+ * Let packet complete handler take care of the packet
+ */
+ status = dmaengine_tx_status(s->chan_rx, s->active_rx, &state);
+ if (status == DMA_COMPLETE) {
+ spin_unlock_irqrestore(&port->lock, flags);
+ dev_dbg(port->dev, "Transaction complete after DMA engine was stopped");
+ return;
+ }
+
/* Handle incomplete DMA receive */
dmaengine_terminate_all(s->chan_rx);
read = sg_dma_len(&s->sg_rx[active]) - state.residue;
--
1.9.1
--
To unsubscribe from this list: send the line "unsubscribe linux-serial" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
