serial: stm32: synchronize RX DMA channel in shutdown

In shutdown, RX DMA channel is terminated. If the DMA RX callback is
scheduled but not yet executed, while a new RX DMA transfer is started, the
callback can be executed, and then disturb the ongoing RX DMA transfer.
To avoid such a case, call dmaengine_synchronize in shutdown, after the
DMA RX channel is terminated.

Signed-off-by: Amelie Delaunay <amelie.delaunay@foss.st.com>
Signed-off-by: Valentin Caron <valentin.caron@foss.st.com>
Link: https://lore.kernel.org/r/20230808161906.178996-7-valentin.caron@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Amelie Delaunay 2023-08-08 18:19:06 +02:00 committed by Greg Kroah-Hartman
parent a01ae50d7e
commit 2490a0ca57

View file

@ -1123,8 +1123,10 @@ static void stm32_usart_shutdown(struct uart_port *port)
dev_err(port->dev, "Transmission is not complete\n");
/* Disable RX DMA. */
if (stm32_port->rx_ch)
if (stm32_port->rx_ch) {
stm32_usart_rx_dma_terminate(stm32_port);
dmaengine_synchronize(stm32_port->rx_ch);
}
/* flush RX & TX FIFO */
if (ofs->rqr != UNDEF_REG)