[PATCH 1/2] serial: tegra: update tx_circular buffer only when TX_DMA is in progress

[PATCH 1/2] serial: tegra: update tx_circular buffer only when TX_DMA is in progress

[Laxman Dewangan]

From: Pradeep Goudagunta <pgoudagunta@nvidia.com>

When channel is require to stop transmit then update the Tx circular
buffer only when DMA based transfer is in progress. If there is no
DMA based transfer then no need to update the Tx buffer.

Signed-off-by: Pradeep Goudagunta <pgoudagunta@nvidia.com>
Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
---
 drivers/tty/serial/serial-tegra.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/tty/serial/serial-tegra.c b/drivers/tty/serial/serial-tegra.c
index d5c2a28..117d8d1 100644
--- a/drivers/tty/serial/serial-tegra.c
+++ b/drivers/tty/serial/serial-tegra.c
@@ -482,6 +482,9 @@ static void tegra_uart_stop_tx(struct uart_port *u)
 	struct dma_tx_state state;
 	int count;
 
+	if (tup->tx_in_progress != TEGRA_UART_TX_DMA)
+		return;
+
 	dmaengine_terminate_all(tup->tx_dma_chan);
 	dmaengine_tx_status(tup->tx_dma_chan, tup->tx_cookie, &state);
 	count = tup->tx_bytes_requested - state.residue;
-- 
1.8.1.5

[PATCH 2/2] serial: tegra: ack the rx dma desc after transfer terminated

[Laxman Dewangan]

From: Pradeep Goudagunta <pgoudagunta@nvidia.com>

The Rx dma descriptor allocated without the DMA_ACK flags so that
once after tarnsfer done or terminated, client can ack the descriptor
to free it for later use.

If the Rx DMA is terminated for some reason then rx-dma descriptor
is not getting acked which causes the memory leak and list of usage
desc to grow continuously.

Hence, acknowledge the rx-dma descriptor once transfer is terminated
to avoid memory leak and desc list to grow.

Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
---
 drivers/tty/serial/serial-tegra.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/tty/serial/serial-tegra.c b/drivers/tty/serial/serial-tegra.c
index 117d8d1..53d7c31 100644
--- a/drivers/tty/serial/serial-tegra.c
+++ b/drivers/tty/serial/serial-tegra.c
@@ -602,6 +602,7 @@ static void tegra_uart_handle_rx_dma(struct tegra_uart_port *tup,
 
 	dmaengine_terminate_all(tup->rx_dma_chan);
 	dmaengine_tx_status(tup->rx_dma_chan,  tup->rx_cookie, &state);
+	async_tx_ack(tup->rx_dma_desc);
 	count = tup->rx_bytes_requested - state.residue;
 
 	/* If we are here, DMA is stopped */
-- 
1.8.1.5