Subject: Re: [PATCH 02/13] tty: serial: atmel: Check return code of
 dmaengine_submit()
To:     Tudor Ambarus <tudor.ambarus@microchip.com>,
        ludovic.desroches@microchip.com, vkoul@kernel.org,
        richard.genoud@gmail.com, gregkh@linuxfoundation.org,
        jirislaby@kernel.org
Cc:     nicolas.ferre@microchip.com, alexandre.belloni@bootlin.com,
        mripard@kernel.org, linux-arm-kernel@lists.infradead.org,
        dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-serial@vger.kernel.org
References: <20211116112036.96349-1-tudor.ambarus@microchip.com>
 <20211116112036.96349-3-tudor.ambarus@microchip.com>
From:   Richard Genoud <richard.genoud@gmail.com>
Message-ID: <e87ef826-1d03-e319-1d27-d876cf4fda5f@gmail.com>
Date:   Fri, 19 Nov 2021 17:27:41 +0100
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Hi,

Le 16/11/2021 à 12:20, Tudor Ambarus a écrit :
> 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>
> ---
>  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;
>  
> 

Acked-by: Richard Genoud <richard.genoud@gmail.com>


Thanks !