This is a note to let you know that I've just added the patch titled
tty: serial: fsl_lpuart: avoid checking for transfer complete when UARTCTRL_SBK is asserted in lpuart32_tx_empty
to the 5.10-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:
tty-serial-fsl_lpuart-avoid-checking-for-transfer-complete-when-uartctrl_sbk-is-asserted-in-lpuart32_tx_empty.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 9425914f3de6febbd6250395f56c8279676d9c3c Mon Sep 17 00:00:00 2001
From: Sherry Sun <sherry.sun@xxxxxxx>
Date: Thu, 23 Mar 2023 13:44:15 +0800
Subject: tty: serial: fsl_lpuart: avoid checking for transfer complete when UARTCTRL_SBK is asserted in lpuart32_tx_empty
From: Sherry Sun <sherry.sun@xxxxxxx>
commit 9425914f3de6febbd6250395f56c8279676d9c3c upstream.
According to LPUART RM, Transmission Complete Flag becomes 0 if queuing
a break character by writing 1 to CTRL[SBK], so here need to avoid
checking for transmission complete when UARTCTRL_SBK is asserted,
otherwise the lpuart32_tx_empty may never get TIOCSER_TEMT.
Commit 2411fd94ceaa("tty: serial: fsl_lpuart: skip waiting for
transmission complete when UARTCTRL_SBK is asserted") only fix it in
lpuart32_set_termios(), here also fix it in lpuart32_tx_empty().
Fixes: 380c966c093e ("tty: serial: fsl_lpuart: add 32-bit register interface support")
Cc: stable <stable@xxxxxxxxxx>
Signed-off-by: Sherry Sun <sherry.sun@xxxxxxx>
Link: https://lore.kernel.org/r/20230323054415.20363-1-sherry.sun@xxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/tty/serial/fsl_lpuart.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
--- a/drivers/tty/serial/fsl_lpuart.c
+++ b/drivers/tty/serial/fsl_lpuart.c
@@ -809,11 +809,17 @@ static unsigned int lpuart32_tx_empty(st
struct lpuart_port, port);
unsigned long stat = lpuart32_read(port, UARTSTAT);
unsigned long sfifo = lpuart32_read(port, UARTFIFO);
+ unsigned long ctrl = lpuart32_read(port, UARTCTRL);
if (sport->dma_tx_in_progress)
return 0;
- if (stat & UARTSTAT_TC && sfifo & UARTFIFO_TXEMPT)
+ /*
+ * LPUART Transmission Complete Flag may never be set while queuing a break
+ * character, so avoid checking for transmission complete when UARTCTRL_SBK
+ * is asserted.
+ */
+ if ((stat & UARTSTAT_TC && sfifo & UARTFIFO_TXEMPT) || ctrl & UARTCTRL_SBK)
return TIOCSER_TEMT;
return 0;
Patches currently in stable-queue which might be from sherry.sun@xxxxxxx are
queue-5.10/tty-serial-fsl_lpuart-avoid-checking-for-transfer-complete-when-uartctrl_sbk-is-asserted-in-lpuart32_tx_empty.patch
