From: Kartik kkartik@nvidia.com
[ 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@nvidia.com Reviewed-by: Ilpo Järvinen ilpo.jarvinen@linux.intel.com Acked-by: Thierry Reding treding@nvidia.com Signed-off-by: Akhil R akhilrajeev@nvidia.com Signed-off-by: Kartik kkartik@nvidia.com Link: https://lore.kernel.org/r/1666105086-17326-1-git-send-email-kkartik@nvidia.c... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/tty/serial/serial-tegra.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/drivers/tty/serial/serial-tegra.c b/drivers/tty/serial/serial-tegra.c index cda71802b698..62377c831894 100644 --- a/drivers/tty/serial/serial-tegra.c +++ b/drivers/tty/serial/serial-tegra.c @@ -614,8 +614,9 @@ 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); @@ -758,8 +759,9 @@ static void tegra_uart_terminate_rx_dma(struct tegra_uart_port *tup) 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;