Terminate any DMA transfer and verify the TX FIFO is empty.
Signed-off-by: Hector Palacios <hector.palacios@xxxxxxxx>
---
drivers/tty/serial/mxs-auart.c | 23 +++++++++++++++++++++++
1 file changed, 23 insertions(+)
diff --git a/drivers/tty/serial/mxs-auart.c b/drivers/tty/serial/mxs-auart.c
index 9f0461778fc1..d9bf6e103f65 100644
--- a/drivers/tty/serial/mxs-auart.c
+++ b/drivers/tty/serial/mxs-auart.c
@@ -782,6 +782,28 @@ static unsigned int mxs_auart_tx_empty(struct uart_port *u)
return 0;
}
+/*
+ * Flush the transmit buffer.
+ * Locking: called with port lock held and IRQs disabled.
+ */
+static void mxs_auart_flush_buffer(struct uart_port *u)
+{
+ struct mxs_auart_port *s = to_auart_port(u);
+ struct dma_chan *channel = s->tx_dma_chan;
+ unsigned int to;
+
+ if (auart_dma_enabled(s)) {
+ /* Avoid deadlock with the DMA engine callback */
+ spin_unlock(&s->port.lock);
+ dmaengine_terminate_all(channel);
+ spin_lock(&s->port.lock);
+ }
+ /* Wait for the FIFO to flush */
+ to = u->timeout;
+ while (!mxs_auart_tx_empty(u) && to--)
+ mdelay(1);
+}
+
static void mxs_auart_start_tx(struct uart_port *u)
{
struct mxs_auart_port *s = to_auart_port(u);
@@ -828,6 +850,7 @@ static struct uart_ops mxs_auart_ops = {
.get_mctrl = mxs_auart_get_mctrl,
.startup = mxs_auart_startup,
.shutdown = mxs_auart_shutdown,
+ .flush_buffer = mxs_auart_flush_buffer,
.set_termios = mxs_auart_settermios,
.type = mxs_auart_type,
.release_port = mxs_auart_release_port,
--
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
