tty: serial: atmel: Check return code of dmaengine_submit()

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>

diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
index 2c99a47..376f7a9 100644 (file)
--- 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;