From 2490a0ca5735714bd2ba8ba8a41fa9343b422113 Mon Sep 17 00:00:00 2001 From: Amelie Delaunay Date: Tue, 8 Aug 2023 18:19:06 +0200 Subject: [PATCH] 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 Signed-off-by: Valentin Caron Link: https://lore.kernel.org/r/20230808161906.178996-7-valentin.caron@foss.st.com Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/stm32-usart.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c index 8fc0526..5e9cf0c 100644 --- a/drivers/tty/serial/stm32-usart.c +++ b/drivers/tty/serial/stm32-usart.c @@ -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) -- 2.7.4