Hi,
On 27. 01. 24, 22:35, Emil Kronborg wrote:
After updating Linux on an i.MX28 board, serial communication over AUART
broke. When I TX from the board and measure on the TX pin, it seems like
the HW fifo is not emptied before the transmission is stopped. I
bisected the bad commit to be 2d141e683e9a ("tty: serial: use
uart_port_tx() helper"). Since it concerns multiple drivers, simply
reverting it is not feasible. One solution would be to effectively
revert the commit for just mxs-auart.c, but maybe you have a better
idea? Any pointers is appreciated.
Hm, the tx stop handling is weird throughout mxs. What about the
attached patch?
thanks,
--
js
suse labs
From 0f5b15374953f1e4b65722b3dbbef9ce14a3c018 Mon Sep 17 00:00:00 2001
From: "Jiri Slaby (SUSE)" <jirislaby@xxxxxxxxxx>
Date: Tue, 30 Jan 2024 10:36:35 +0100
Subject: [PATCH] mxs: fix
Signed-off-by: Jiri Slaby (SUSE) <jirislaby@xxxxxxxxxx>
---
drivers/tty/serial/mxs-auart.c | 5 ++++-
include/linux/serial_core.h | 10 ++++++----
2 files changed, 10 insertions(+), 5 deletions(-)
diff --git a/drivers/tty/serial/mxs-auart.c b/drivers/tty/serial/mxs-auart.c
index 424db8466755..ec013d13cc3d 100644
--- a/drivers/tty/serial/mxs-auart.c
+++ b/drivers/tty/serial/mxs-auart.c
@@ -594,13 +594,16 @@ static void mxs_auart_tx_chars(struct mxs_auart_port *s)
return;
}
- pending = uart_port_tx(&s->port, ch,
+ pending = uart_port_tx_no_stop(&s->port, ch,
!(mxs_read(s, REG_STAT) & AUART_STAT_TXFF),
mxs_write(ch, s, REG_DATA));
if (pending)
mxs_set(AUART_INTR_TXIEN, s, REG_INTR);
else
mxs_clr(AUART_INTR_TXIEN, s, REG_INTR);
+
+ if (uart_tx_stopped(&s->port))
+ mxs_auart_stop_tx(&s->port);
}
static void mxs_auart_rx_char(struct mxs_auart_port *s)
diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
index c5fa72c8f96e..18256fd765c9 100644
--- a/include/linux/serial_core.h
+++ b/include/linux/serial_core.h
@@ -769,7 +769,7 @@ struct uart_driver {
void uart_write_wakeup(struct uart_port *port);
-#define __uart_port_tx(uport, ch, tx_ready, put_char, tx_done, for_test, \
+#define __uart_port_tx(uport, ch, tx_ready, put_char, should_stop, tx_done, for_test, \
for_post) \
({ \
struct uart_port *__port = (uport); \
@@ -799,7 +799,7 @@ void uart_write_wakeup(struct uart_port *port);
if (pending < WAKEUP_CHARS) { \
uart_write_wakeup(__port); \
\
- if (pending == 0) \
+ if (should_stop && pending == 0) \
__port->ops->stop_tx(__port); \
} \
\
@@ -834,7 +834,7 @@ void uart_write_wakeup(struct uart_port *port);
*/
#define uart_port_tx_limited(port, ch, count, tx_ready, put_char, tx_done) ({ \
unsigned int __count = (count); \
- __uart_port_tx(port, ch, tx_ready, put_char, tx_done, __count, \
+ __uart_port_tx(port, ch, tx_ready, put_char, true, tx_done, __count, \
__count--); \
})
@@ -848,8 +848,10 @@ void uart_write_wakeup(struct uart_port *port);
* See uart_port_tx_limited() for more details.
*/
#define uart_port_tx(port, ch, tx_ready, put_char) \
- __uart_port_tx(port, ch, tx_ready, put_char, ({}), true, ({}))
+ __uart_port_tx(port, ch, tx_ready, put_char, true, ({}), true, ({}))
+#define uart_port_tx_no_stop(port, ch, tx_ready, put_char) \
+ __uart_port_tx(port, ch, tx_ready, put_char, false, ({}), true, ({}))
/*
* Baud rate helpers.
*/
--
2.43.0
