This is a note to let you know that I've just added the patch titled
serial: tegra: Read DMA status before terminating
to the 4.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
serial-tegra-read-dma-status-before-terminating.patch
and it can be found in the queue-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 7ac4008a0a23e9036c10fce3b8506b5ec91e7b1f
Author: Kartik <kkartik@xxxxxxxxxx>
Date: Tue Oct 18 20:28:06 2022 +0530
serial: tegra: Read DMA status before terminating
[ Upstream commit 109a951a9f1fd8a34ebd1896cbbd5d5cede880a7 ]
Read the DMA status before terminating the DMA, as doing so deletes
the DMA desc.
Also, to get the correct transfer status information, pause the DMA
using dmaengine_pause() before reading the DMA status.
Fixes: e9ea096dd225 ("serial: tegra: add serial driver")
Reviewed-by: Jon Hunter <jonathanh@xxxxxxxxxx>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx>
Acked-by: Thierry Reding <treding@xxxxxxxxxx>
Signed-off-by: Akhil R <akhilrajeev@xxxxxxxxxx>
Signed-off-by: Kartik <kkartik@xxxxxxxxxx>
Link: https://lore.kernel.org/r/1666105086-17326-1-git-send-email-kkartik@xxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/tty/serial/serial-tegra.c b/drivers/tty/serial/serial-tegra.c
index 1d957144117e..cc613240a351 100644
--- a/drivers/tty/serial/serial-tegra.c
+++ b/drivers/tty/serial/serial-tegra.c
@@ -570,8 +570,9 @@ static void tegra_uart_stop_tx(struct uart_port *u)
if (tup->tx_in_progress != TEGRA_UART_TX_DMA)
return;
- dmaengine_terminate_all(tup->tx_dma_chan);
+ dmaengine_pause(tup->tx_dma_chan);
dmaengine_tx_status(tup->tx_dma_chan, tup->tx_cookie, &state);
+ dmaengine_terminate_all(tup->tx_dma_chan);
count = tup->tx_bytes_requested - state.residue;
async_tx_ack(tup->tx_dma_desc);
uart_xmit_advance(&tup->uport, count);
@@ -697,8 +698,9 @@ static void tegra_uart_terminate_rx_dma(struct tegra_uart_port *tup)
if (!tup->rx_dma_active)
return;
- dmaengine_terminate_all(tup->rx_dma_chan);
+ dmaengine_pause(tup->rx_dma_chan);
dmaengine_tx_status(tup->rx_dma_chan, tup->rx_cookie, &state);
+ dmaengine_terminate_all(tup->rx_dma_chan);
tegra_uart_rx_buffer_push(tup, state.residue);
tup->rx_dma_active = false;
