diff mbox series

[v2] serial: tegra: Read DMA status before terminating

Message ID 1666105086-17326-1-git-send-email-kkartik@nvidia.com
State New
Headers
Series [v2] serial: tegra: Read DMA status before terminating |

Commit Message

Kartik Rajput Oct. 18, 2022, 2:58 p.m. UTC 
  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")

Signed-off-by: Akhil R <akhilrajeev@nvidia.com>
Signed-off-by: Kartik <kkartik@nvidia.com>
---
v1->v2:
 * Pause the DMA before reading the DMA status.
 * Updated commit message.

 drivers/tty/serial/serial-tegra.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

Comments

Thierry Reding Oct. 18, 2022, 3:19 p.m. UTC | #1 
On Tue, Oct 18, 2022 at 08:28:06PM +0530, Kartik wrote:
> 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")
> 
> Signed-off-by: Akhil R <akhilrajeev@nvidia.com>
> Signed-off-by: Kartik <kkartik@nvidia.com>
> ---
> v1->v2:
>  * Pause the DMA before reading the DMA status.
>  * Updated commit message.
> 
>  drivers/tty/serial/serial-tegra.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)

Seems fine:

Acked-by: Thierry Reding <treding@nvidia.com>
Ilpo Järvinen Oct. 19, 2022, 9:12 a.m. UTC | #2 
On Tue, 18 Oct 2022, Kartik wrote:

> 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")
> 
> Signed-off-by: Akhil R <akhilrajeev@nvidia.com>
> Signed-off-by: Kartik <kkartik@nvidia.com>
> ---
> v1->v2:
>  * Pause the DMA before reading the DMA status.
>  * Updated commit message.
> 
>  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 b7170cb9a544..cda9cd4fa92c 100644
> --- a/drivers/tty/serial/serial-tegra.c
> +++ b/drivers/tty/serial/serial-tegra.c
> @@ -619,8 +619,9 @@ 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);
> @@ -763,8 +764,9 @@ 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;

Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Jon Hunter Oct. 19, 2022, 9:48 a.m. UTC | #3 
On 18/10/2022 15:58, Kartik wrote:
> 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")
> 
> Signed-off-by: Akhil R <akhilrajeev@nvidia.com>
> Signed-off-by: Kartik <kkartik@nvidia.com>
> ---
> v1->v2:
>   * Pause the DMA before reading the DMA status.
>   * Updated commit message.
> 
>   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 b7170cb9a544..cda9cd4fa92c 100644
> --- a/drivers/tty/serial/serial-tegra.c
> +++ b/drivers/tty/serial/serial-tegra.c
> @@ -619,8 +619,9 @@ 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);
> @@ -763,8 +764,9 @@ 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;

Thanks!

Reviewed-by: Jon Hunter <jonathanh@nvidia.com>

Jon
diff mbox series

Patch

diff --git a/drivers/tty/serial/serial-tegra.c b/drivers/tty/serial/serial-tegra.c
index b7170cb9a544..cda9cd4fa92c 100644
--- a/drivers/tty/serial/serial-tegra.c
+++ b/drivers/tty/serial/serial-tegra.c
@@ -619,8 +619,9 @@  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);
@@ -763,8 +764,9 @@  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;