From 1e67bd2b8cb90b66e89562598e9c2046246832d3 Mon Sep 17 00:00:00 2001
From: Tudor Ambarus <tudor.ambarus@microchip.com>
Date: Thu, 25 Nov 2021 11:00:17 +0200
Subject: [PATCH] tty: serial: atmel: Check return code of dmaengine_submit()
Git-commit: 1e67bd2b8cb90b66e89562598e9c2046246832d3
Patch-mainline: v5.17-rc1
References: git-fixes

The tx_submit() method of struct dma_async_tx_descriptor is entitled
to do sanity checks and return errors if encountered. It's not the
case for the DMA controller drivers that this client is using
(at_h/xdmac), because they currently don't do sanity checks and always
return a positive cookie at tx_submit() method. In case the controller
drivers will implement sanity checks and return errors, print a message
so that the client will be informed that something went wrong at
tx_submit() level.

Fixes: 08f738be88bb ("serial: at91: add tx dma support")
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Acked-by: Richard Genoud <richard.genoud@gmail.com>
Link: https://lore.kernel.org/r/20211125090028.786832-3-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 | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
index 2c99a47a2535..376f7a9c2868 100644
--- a/drivers/tty/serial/atmel_serial.c
+++ b/drivers/tty/serial/atmel_serial.c
@@ -1004,6 +1004,11 @@ static void atmel_tx_dma(struct uart_port *port)
 		desc->callback = atmel_complete_tx_dma;
 		desc->callback_param = atmel_port;
 		atmel_port->cookie_tx = dmaengine_submit(desc);
+		if (dma_submit_error(atmel_port->cookie_tx)) {
+			dev_err(port->dev, "dma_submit_error %d\n",
+				atmel_port->cookie_tx);
+			return;
+		}
 	}
 
 	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
@@ -1258,6 +1263,11 @@ static int atmel_prepare_rx_dma(struct uart_port *port)
 	desc->callback_param = port;
 	atmel_port->desc_rx = desc;
 	atmel_port->cookie_rx = dmaengine_submit(desc);
+	if (dma_submit_error(atmel_port->cookie_rx)) {
+		dev_err(port->dev, "dma_submit_error %d\n",
+			atmel_port->cookie_rx);
+		goto chan_err;
+	}
 
 	return 0;
 
-- 
2.31.1