This is a note to let you know that I've just added the patch titled
serial: stm32: fix clearing interrupt error flags
to my tty git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty.git
in the tty-testing branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will be merged to the tty-next branch sometime soon,
after it passes testing, and the merge window is open.
If you have any questions about this process, please let me know.
>From 1250ed7114a977cdc2a67a0c09d6cdda63970eb9 Mon Sep 17 00:00:00 2001
From: Fabrice Gasnier <fabrice.gasnier@xxxxxx>
Date: Thu, 21 Nov 2019 09:10:49 +0100
Subject: serial: stm32: fix clearing interrupt error flags
The interrupt clear flag register is a "write 1 to clear" register.
So, only writing ones allows to clear flags:
- Replace buggy stm32_clr_bits() by a simple write to clear error flags
- Replace useless read/modify/write stm32_set_bits() routine by a
simple write to clear TC (transfer complete) flag.
Fixes: 4f01d833fdcd ("serial: stm32: fix rx error handling")
Signed-off-by: Fabrice Gasnier <fabrice.gasnier@xxxxxx>
Cc: stable <stable@xxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/1574323849-1909-1-git-send-email-fabrice.gasnier@xxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/tty/serial/stm32-usart.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c
index df90747ee3a8..2f72514d63ed 100644
--- a/drivers/tty/serial/stm32-usart.c
+++ b/drivers/tty/serial/stm32-usart.c
@@ -240,8 +240,8 @@ static void stm32_receive_chars(struct uart_port *port, bool threaded)
* cleared by the sequence [read SR - read DR].
*/
if ((sr & USART_SR_ERR_MASK) && ofs->icr != UNDEF_REG)
- stm32_clr_bits(port, ofs->icr, USART_ICR_ORECF |
- USART_ICR_PECF | USART_ICR_FECF);
+ writel_relaxed(sr & USART_SR_ERR_MASK,
+ port->membase + ofs->icr);
c = stm32_get_char(port, &sr, &stm32_port->last_res);
port->icount.rx++;
@@ -435,7 +435,7 @@ static void stm32_transmit_chars(struct uart_port *port)
if (ofs->icr == UNDEF_REG)
stm32_clr_bits(port, ofs->isr, USART_SR_TC);
else
- stm32_set_bits(port, ofs->icr, USART_ICR_TCCF);
+ writel_relaxed(USART_ICR_TCCF, port->membase + ofs->icr);
if (stm32_port->tx_ch)
stm32_transmit_chars_dma(port);
--
2.24.0
