tty: serial: fsl_lpuart: Ignore TX/RX interrupts if DMA is enabled

In a mixed DMA/IRQ use-case (e.g.: DMA for TX, IRQ for RX), interrupt
handler might try to handle Rx/Tx condition it shouldn't. Change the
code to only handle TX/RX event if corresponding path isn't being
handled by DMA.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Cc: Stefan Agner <stefan@agner.ch>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Cory Tusar <cory.tusar@zii.aero>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-imx@nxp.com
Cc: linux-serial@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Link: https://lore.kernel.org/r/20190805185701.22863-7-andrew.smirnov@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c
index 5c3cc10..3e17bb8 100644 (file)
--- a/drivers/tty/serial/fsl_lpuart.c
+++ b/drivers/tty/serial/fsl_lpuart.c
@@ -967,10 +967,10 @@ static irqreturn_t lpuart_int(int irq, void *dev_id)
 
        sts = readb(sport->port.membase + UARTSR1);
 
-       if (sts & UARTSR1_RDRF)
+       if (sts & UARTSR1_RDRF && !sport->lpuart_dma_rx_use)
                lpuart_rxint(sport);
 
-       if (sts & UARTSR1_TDRE)
+       if (sts & UARTSR1_TDRE && !sport->lpuart_dma_tx_use)
                lpuart_txint(sport);
 
        return IRQ_HANDLED;