From: Esben Haabendal <esben@geanix.com>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Jiri Slaby <jirislaby@kernel.org>,
Shawn Guo <shawnguo@kernel.org>,
Sascha Hauer <s.hauer@pengutronix.de>,
Pengutronix Kernel Team <kernel@pengutronix.de>,
Fabio Estevam <festevam@gmail.com>
Cc: Marc Kleine-Budde <mkl@pengutronix.de>,
linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org,
imx@lists.linux.dev, linux-arm-kernel@lists.infradead.org
Subject: [PATCH 1/2] serial: imx: Introduce timeout when waiting on transmitter empty
Date: Fri, 5 Apr 2024 11:25:13 +0200 [thread overview]
Message-ID: <76cf9ce9cbf9dcdf78bc00ce7a919db1776ebce1.1712309058.git.esben@geanix.com> (raw)
By waiting at most 1 second for USR2_TXDC to be set, we avoid a potentital
deadlock.
In case of the timeout, there is not much we can do, so we simply ignore
the transmitter state and optimistically try to continue.
Signed-off-by: Esben Haabendal <esben@geanix.com>
Acked-by: Marc Kleine-Budde <mkl@pengutronix.de>
---
drivers/tty/serial/imx.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
index e14813250616..09c1678ddfd4 100644
--- a/drivers/tty/serial/imx.c
+++ b/drivers/tty/serial/imx.c
@@ -26,6 +26,7 @@
#include <linux/slab.h>
#include <linux/of.h>
#include <linux/io.h>
+#include <linux/iopoll.h>
#include <linux/dma-mapping.h>
#include <asm/irq.h>
@@ -2010,7 +2011,7 @@ imx_uart_console_write(struct console *co, const char *s, unsigned int count)
struct imx_port *sport = imx_uart_ports[co->index];
struct imx_port_ucrs old_ucr;
unsigned long flags;
- unsigned int ucr1;
+ unsigned int ucr1, usr2;
int locked = 1;
if (sport->port.sysrq)
@@ -2041,8 +2042,8 @@ imx_uart_console_write(struct console *co, const char *s, unsigned int count)
* Finally, wait for transmitter to become empty
* and restore UCR1/2/3
*/
- while (!(imx_uart_readl(sport, USR2) & USR2_TXDC));
-
+ read_poll_timeout_atomic(imx_uart_readl, usr2, usr2 & USR2_TXDC,
+ 0, USEC_PER_SEC, false, sport, USR2);
imx_uart_ucrs_restore(sport, &old_ucr);
if (locked)
--
2.44.0
next reply other threads:[~2024-04-05 9:25 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-05 9:25 Esben Haabendal [this message]
2024-04-05 9:49 ` [PATCH 1/2] serial: imx: Introduce timeout when waiting on transmitter empty Marc Kleine-Budde
2024-04-05 17:22 ` Esben Haabendal
2024-04-05 17:33 ` Marc Kleine-Budde
2024-04-08 8:57 ` Esben Haabendal
2024-04-05 17:38 ` Fabio Estevam
2024-04-05 19:05 ` Sergey Organov
2024-04-08 8:56 ` Esben Haabendal
2024-04-10 7:18 ` [PATCH v2] " Esben Haabendal
2024-04-11 12:06 ` Greg Kroah-Hartman
2024-04-11 12:18 ` Esben Haabendal
2024-04-11 12:19 ` [PATCH v3] " Esben Haabendal
2024-05-02 9:14 ` Esben Haabendal
2024-05-04 16:03 ` Greg Kroah-Hartman
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