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From: Valentin Caron <valentin.caron@foss.st.com>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jirislaby@kernel.org>,
	Alexandre Torgue <alexandre.torgue@foss.st.com>,
	Amelie Delaunay <amelie.delaunay@foss.st.com>,
	<linux-serial@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
	<linux-stm32@st-md-mailman.stormreply.com>,
	<linux-arm-kernel@lists.infradead.org>,
	Valentin Caron <valentin.caron@foss.st.com>
Subject: [PATCH v2 6/6] serial: stm32: synchronize RX DMA channel in shutdown
Date: Tue, 8 Aug 2023 18:19:06 +0200	[thread overview]
Message-ID: <20230808161906.178996-7-valentin.caron@foss.st.com> (raw)
In-Reply-To: <20230808161906.178996-1-valentin.caron@foss.st.com>

From: Amelie Delaunay <amelie.delaunay@foss.st.com>

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>
---
 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 8fc0526be898..5e9cf0c48813 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)
-- 
2.25.1


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      parent reply	other threads:[~2023-08-08 16:21 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-08-08 16:19 [PATCH v2 0/6] serial: stm32: improve DMA pause and resume Valentin Caron
2023-08-08 16:19 ` [PATCH v2 1/6] serial: stm32: avoid clearing DMAT bit during transfer Valentin Caron
2023-08-08 16:19 ` [PATCH v2 2/6] serial: stm32: use DMAT as a configuration bit Valentin Caron
2023-08-08 16:19 ` [PATCH v2 3/6] serial: stm32: modify parameter and rename stm32_usart_rx_dma_enabled Valentin Caron
2023-08-08 16:19 ` [PATCH v2 4/6] serial: stm32: group dma pause/resume error handling into single function Valentin Caron
2023-08-08 16:19 ` [PATCH v2 5/6] serial: stm32: replace access to DMAR bit by dmaengine_pause/resume Valentin Caron
2023-08-08 16:19 ` Valentin Caron [this message]

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