From 4f4b9b5895614eb2e2b5f4cab7858f44bd113e1b Mon Sep 17 00:00:00 2001

From: Tudor Ambarus <tudor.ambarus@microchip.com>

Date: Thu, 25 Nov 2021 11:00:18 +0200

Subject: [PATCH] tty: serial: atmel: Call dma_async_issue_pending()

Git-commit: 4f4b9b5895614eb2e2b5f4cab7858f44bd113e1b

Patch-mainline: v5.17-rc1

References: git-fixes

The driver wrongly assummed that tx_submit() will start the transfer,

which is not the case, now that the at_xdmac driver is fixed. tx_submit

is supposed to push the current transaction descriptor to a pending queue,

waiting for issue_pending to be called. issue_pending must start the

transfer, not tx_submit.

Fixes: 34df42f59a60 ("serial: at91: add rx dma support")

Fixes: 08f738be88bb ("serial: at91: add tx dma support")

Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>

Link: https://lore.kernel.org/r/20211125090028.786832-4-tudor.ambarus@microchip.com

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Acked-by: Takashi Iwai <tiwai@suse.de>

---

 drivers/tty/serial/atmel_serial.c | 4 ++++

 1 file changed, 4 insertions(+)

diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c

index 376f7a9c2868..269b4500e9e7 100644

--- a/drivers/tty/serial/atmel_serial.c

+++ b/drivers/tty/serial/atmel_serial.c

@@ -1009,6 +1009,8 @@ static void atmel_tx_dma(struct uart_port *port)

 				atmel_port->cookie_tx);

 			return;

 		}

+

+		dma_async_issue_pending(chan);

 	}

 	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)

@@ -1269,6 +1271,8 @@ static int atmel_prepare_rx_dma(struct uart_port *port)

 		goto chan_err;

 	}

+	dma_async_issue_pending(atmel_port->chan_rx);

+

 	return 0;

 chan_err:

-- 

2.31.1