This is a note to let you know that I've just added the patch titled
serial: mvebu-uart: uart2 error bits clearing
to the 5.4-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:
serial-mvebu-uart-uart2-error-bits-clearing.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From a7209541239e5dd44d981289e5f9059222d40fd1 Mon Sep 17 00:00:00 2001
From: Narendra Hadke <nhadke@xxxxxxxxxxx>
Date: Tue, 26 Jul 2022 11:12:21 +0200
Subject: serial: mvebu-uart: uart2 error bits clearing
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From: Narendra Hadke <nhadke@xxxxxxxxxxx>
commit a7209541239e5dd44d981289e5f9059222d40fd1 upstream.
For mvebu uart2, error bits are not cleared on buffer read.
This causes interrupt loop and system hang.
Cc: stable@xxxxxxxxxxxxxxx
Reviewed-by: Yi Guo <yi.guo@xxxxxxxxxx>
Reviewed-by: Nadav Haklai <nadavh@xxxxxxxxxxx>
Signed-off-by: Narendra Hadke <nhadke@xxxxxxxxxxx>
Signed-off-by: Pali Rohár <pali@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20220726091221.12358-1-pali@xxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/tty/serial/mvebu-uart.c | 11 +++++++++++
1 file changed, 11 insertions(+)
--- a/drivers/tty/serial/mvebu-uart.c
+++ b/drivers/tty/serial/mvebu-uart.c
@@ -238,6 +238,7 @@ static void mvebu_uart_rx_chars(struct u
struct tty_port *tport = &port->state->port;
unsigned char ch = 0;
char flag = 0;
+ int ret;
do {
if (status & STAT_RX_RDY(port)) {
@@ -250,6 +251,16 @@ static void mvebu_uart_rx_chars(struct u
port->icount.parity++;
}
+ /*
+ * For UART2, error bits are not cleared on buffer read.
+ * This causes interrupt loop and system hang.
+ */
+ if (IS_EXTENDED(port) && (status & STAT_BRK_ERR)) {
+ ret = readl(port->membase + UART_STAT);
+ ret |= STAT_BRK_ERR;
+ writel(ret, port->membase + UART_STAT);
+ }
+
if (status & STAT_BRK_DET) {
port->icount.brk++;
status &= ~(STAT_FRM_ERR | STAT_PAR_ERR);
Patches currently in stable-queue which might be from nhadke@xxxxxxxxxxx are
queue-5.4/serial-mvebu-uart-uart2-error-bits-clearing.patch
