linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Mathieu Poirier <mathieu.poirier@linaro.org>
To: stable@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Subject: [stable 4.19][PATCH 1/3] serial: uartps: Add a timeout to the tx empty wait
Date: Mon, 10 Feb 2020 10:18:25 -0700	[thread overview]
Message-ID: <20200210171827.29693-2-mathieu.poirier@linaro.org> (raw)
In-Reply-To: <20200210171827.29693-1-mathieu.poirier@linaro.org>

From: Shubhrajyoti Datta <shubhrajyoti.datta@xilinx.com>

commit 277375b864e8147975b064b513f491e2a910e66a upstream

In case the cable is not connected then the target gets into
an infinite wait for tx empty.
Add a timeout to the tx empty wait.

Reported-by: Jean-Francois Dagenais <jeff.dagenais@gmail.com>
Signed-off-by: Shubhrajyoti Datta <shubhrajyoti.datta@xilinx.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: stable <stable@vger.kernel.org> # 4.19
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
---
 drivers/tty/serial/xilinx_uartps.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c
index 66d49d511885..7cbee19ea93d 100644
--- a/drivers/tty/serial/xilinx_uartps.c
+++ b/drivers/tty/serial/xilinx_uartps.c
@@ -26,6 +26,7 @@
 #include <linux/of.h>
 #include <linux/module.h>
 #include <linux/pm_runtime.h>
+#include <linux/iopoll.h>
 
 #define CDNS_UART_TTY_NAME	"ttyPS"
 #define CDNS_UART_NAME		"xuartps"
@@ -34,6 +35,7 @@
 #define CDNS_UART_NR_PORTS	2
 #define CDNS_UART_FIFO_SIZE	64	/* FIFO size */
 #define CDNS_UART_REGISTER_SPACE	0x1000
+#define TX_TIMEOUT		500000
 
 /* Rx Trigger level */
 static int rx_trigger_level = 56;
@@ -681,16 +683,20 @@ static void cdns_uart_set_termios(struct uart_port *port,
 	unsigned int cval = 0;
 	unsigned int baud, minbaud, maxbaud;
 	unsigned long flags;
-	unsigned int ctrl_reg, mode_reg;
+	unsigned int ctrl_reg, mode_reg, val;
+	int err;
 
 	spin_lock_irqsave(&port->lock, flags);
 
 	/* Wait for the transmit FIFO to empty before making changes */
 	if (!(readl(port->membase + CDNS_UART_CR) &
 				CDNS_UART_CR_TX_DIS)) {
-		while (!(readl(port->membase + CDNS_UART_SR) &
-				CDNS_UART_SR_TXEMPTY)) {
-			cpu_relax();
+		err = readl_poll_timeout(port->membase + CDNS_UART_SR,
+					 val, (val & CDNS_UART_SR_TXEMPTY),
+					 1000, TX_TIMEOUT);
+		if (err) {
+			dev_err(port->dev, "timed out waiting for tx empty");
+			return;
 		}
 	}
 
-- 
2.20.1


  reply	other threads:[~2020-02-10 17:18 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-10 17:18 [stable 4.19][PATCH 0/3] stable: Candidates for 4.19.y Mathieu Poirier
2020-02-10 17:18 ` Mathieu Poirier [this message]
2020-02-10 17:18 ` [stable 4.19][PATCH 2/3] gpio: zynq: Report gpio direction at boot Mathieu Poirier
2020-02-10 17:18 ` [stable 4.19][PATCH 3/3] spi: spi-mem: Add extra sanity checks on the op param Mathieu Poirier
2020-02-12 13:12 ` [stable 4.19][PATCH 0/3] stable: Candidates for 4.19.y Sasha Levin

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20200210171827.29693-2-mathieu.poirier@linaro.org \
    --to=mathieu.poirier@linaro.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=stable@vger.kernel.org \
    --subject='Re: [stable 4.19][PATCH 1/3] serial: uartps: Add a timeout to the tx empty wait' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).