[PATCH AUTOSEL 4.19 122/206] serial: 8250: 8250_omap: Terminate DMA before pushing data on RX timeout

[Sasha Levin]

From: Vignesh Raghavendra <vigneshr@xxxxxx>

[ Upstream commit 7cf4df30a98175033e9849f7f16c46e96ba47f41 ]

Terminate and flush DMA internal buffers, before pushing RX data to
higher layer. Otherwise, this will lead to data corruption, as driver
would end up pushing stale buffer data to higher layer while actual data
is still stuck inside DMA hardware and has yet not arrived at the
memory.
While at that, replace deprecated dmaengine_terminate_all() with
dmaengine_terminate_async().

Signed-off-by: Vignesh Raghavendra <vigneshr@xxxxxx>
Link: https://lore.kernel.org/r/20200319110344.21348-2-vigneshr@xxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/tty/serial/8250/8250_omap.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/tty/serial/8250/8250_omap.c b/drivers/tty/serial/8250/8250_omap.c
index a7e555e413a69..cbd006fb7fbb9 100644
--- a/drivers/tty/serial/8250/8250_omap.c
+++ b/drivers/tty/serial/8250/8250_omap.c
@@ -781,7 +781,10 @@ static void __dma_rx_do_complete(struct uart_8250_port *p)
 	dmaengine_tx_status(dma->rxchan, dma->rx_cookie, &state);
 
 	count = dma->rx_size - state.residue;
-
+	if (count < dma->rx_size)
+		dmaengine_terminate_async(dma->rxchan);
+	if (!count)
+		goto unlock;
 	ret = tty_insert_flip_string(tty_port, dma->rx_buf, count);
 
 	p->port.icount.rx += ret;
@@ -843,7 +846,6 @@ static void omap_8250_rx_dma_flush(struct uart_8250_port *p)
 	spin_unlock_irqrestore(&priv->rx_dma_lock, flags);
 
 	__dma_rx_do_complete(p);
-	dmaengine_terminate_all(dma->rxchan);
 }
 
 static int omap_8250_rx_dma(struct uart_8250_port *p)
-- 
2.25.1