[PATCH 5.15 335/846] serial: stm32: move tx dma terminate DMA to shutdown

[Greg Kroah-Hartman]

From: Valentin Caron <valentin.caron@xxxxxxxxxxx>

[ Upstream commit 56a23f9319e86e1d62a109896e2c7e52c414e67d ]

Terminate DMA transaction and clear CR3_DMAT when shutdown is requested,
instead of when remove is requested. If DMA transfer is not stopped in
shutdown ops, driver will fail to start a new DMA transfer after next
startup ops.

Fixes: 3489187204eb ("serial: stm32: adding dma support")
Signed-off-by: Erwan Le Ray <erwan.leray@xxxxxxxxxxx>
Signed-off-by: Valentin Caron <valentin.caron@xxxxxxxxxxx>
Link: https://lore.kernel.org/r/20220104182445.4195-2-valentin.caron@xxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/tty/serial/stm32-usart.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c
index 8f032e77b954a..3366914dad7a8 100644
--- a/drivers/tty/serial/stm32-usart.c
+++ b/drivers/tty/serial/stm32-usart.c
@@ -691,6 +691,11 @@ static void stm32_usart_shutdown(struct uart_port *port)
 	u32 val, isr;
 	int ret;
 
+	if (stm32_port->tx_dma_busy) {
+		dmaengine_terminate_async(stm32_port->tx_ch);
+		stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_DMAT);
+	}
+
 	/* Disable modem control interrupts */
 	stm32_usart_disable_ms(port);
 
@@ -1385,7 +1390,6 @@ static int stm32_usart_serial_remove(struct platform_device *pdev)
 	stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_DMAR);
 
 	if (stm32_port->tx_ch) {
-		dmaengine_terminate_async(stm32_port->tx_ch);
 		stm32_usart_of_dma_tx_remove(stm32_port, pdev);
 		dma_release_channel(stm32_port->tx_ch);
 	}
-- 
2.34.1