From: Andrey Smirnov <andrew.smirnov@gmail.com>
Date: Mon, 5 Aug 2019 11:57:01 -0700
Subject: tty: serial: fsl_lpuart: Ignore TX/RX interrupts if DMA is enabled
Git-commit: 6798e901ab237ae51a3d192d571ec1e462e962b5
Patch-mainline: v5.4-rc1
References: jsc#SLE-12251
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>
Signed-off-by: Mian Yousaf Kaukab <yousaf.kaukab@suse.com>
---
drivers/tty/serial/fsl_lpuart.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c
index 5c3cc1051aa8..3e17bb8a0b16 100644
--- 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;
--
2.26.2