Patch "serial: imx: Fix clearing of receiver overrun flag" has been added to the 4.0-stable tree

Patch "serial: imx: Fix clearing of receiver overrun flag" has been added to the 4.0-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    serial: imx: Fix clearing of receiver overrun flag

to the 4.0-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     serial-imx-fix-clearing-of-receiver-overrun-flag.patch
and it can be found in the queue-4.0 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 91555ce9012557b2d621d7b0b6ec694218a2a9bc Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig?= <u.kleine-koenig@pengutronix.de>
Date: Tue, 24 Feb 2015 11:17:05 +0100
Subject: serial: imx: Fix clearing of receiver overrun flag
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From: =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig?= <u.kleine-koenig@pengutronix.de>

commit 91555ce9012557b2d621d7b0b6ec694218a2a9bc upstream.

The writeable bits in the USR2 register are all "write 1 to
clear" so only write the bits that actually should be cleared.

Fixes: f1f836e4209e ("serial: imx: Add Rx Fifo overrun error message")
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/tty/serial/imx.c |    8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

--- a/drivers/tty/serial/imx.c
+++ b/drivers/tty/serial/imx.c
@@ -818,7 +818,7 @@ static irqreturn_t imx_int(int irq, void
 	if (sts2 & USR2_ORE) {
 		dev_err(sport->port.dev, "Rx FIFO overrun\n");
 		sport->port.icount.overrun++;
-		writel(sts2 | USR2_ORE, sport->port.membase + USR2);
+		writel(USR2_ORE, sport->port.membase + USR2);
 	}
 
 	return IRQ_HANDLED;
@@ -1181,10 +1181,12 @@ static int imx_startup(struct uart_port
 		imx_uart_dma_init(sport);
 
 	spin_lock_irqsave(&sport->port.lock, flags);
+
 	/*
 	 * Finally, clear and enable interrupts
 	 */
 	writel(USR1_RTSD, sport->port.membase + USR1);
+	writel(USR2_ORE, sport->port.membase + USR2);
 
 	if (sport->dma_is_inited && !sport->dma_is_enabled)
 		imx_enable_dma(sport);
@@ -1199,10 +1201,6 @@ static int imx_startup(struct uart_port
 
 	writel(temp, sport->port.membase + UCR1);
 
-	/* Clear any pending ORE flag before enabling interrupt */
-	temp = readl(sport->port.membase + USR2);
-	writel(temp | USR2_ORE, sport->port.membase + USR2);
-
 	temp = readl(sport->port.membase + UCR4);
 	temp |= UCR4_OREN;
 	writel(temp, sport->port.membase + UCR4);


Patches currently in stable-queue which might be from u.kleine-koenig@pengutronix.de are

queue-4.0/ring-buffer-replace-this_cpu_-with-__this_cpu_.patch
queue-4.0/serial-imx-fix-clearing-of-receiver-overrun-flag.patch