From 56a23f9319e86e1d62a109896e2c7e52c414e67d Mon Sep 17 00:00:00 2001
From: Valentin Caron <valentin.caron@foss.st.com>
Date: Tue, 4 Jan 2022 19:24:42 +0100
Subject: [PATCH] serial: stm32: move tx dma terminate DMA to shutdown
Git-commit: 56a23f9319e86e1d62a109896e2c7e52c414e67d
Patch-mainline: v5.17-rc1
References: git-fixes

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@foss.st.com>
Signed-off-by: Valentin Caron <valentin.caron@foss.st.com>
Link: https://lore.kernel.org/r/20220104182445.4195-2-valentin.caron@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/tty/serial/stm32-usart.c |    6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

--- a/drivers/tty/serial/stm32-usart.c
+++ b/drivers/tty/serial/stm32-usart.c
@@ -691,6 +691,11 @@ static void stm32_usart_shutdown(struct
 	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);
 
@@ -1386,7 +1391,6 @@ static int stm32_usart_serial_remove(str
 	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);
 	}