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 5.19-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-5.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 040076f0ab10143dc046c3347c9b3c04d0330d7a
Author: Narendra Hadke <nhadke@xxxxxxxxxxx>
Date: Tue Jul 26 11:12:21 2022 +0200
serial: mvebu-uart: uart2 error bits clearing
[ Upstream commit a7209541239e5dd44d981289e5f9059222d40fd1 ]
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>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/tty/serial/mvebu-uart.c b/drivers/tty/serial/mvebu-uart.c
index 93489fe334d0..65eaecd10b7c 100644
--- a/drivers/tty/serial/mvebu-uart.c
+++ b/drivers/tty/serial/mvebu-uart.c
@@ -265,6 +265,7 @@ static void mvebu_uart_rx_chars(struct uart_port *port, unsigned int status)
struct tty_port *tport = &port->state->port;
unsigned char ch = 0;
char flag = 0;
+ int ret;
do {
if (status & STAT_RX_RDY(port)) {
@@ -277,6 +278,16 @@ static void mvebu_uart_rx_chars(struct uart_port *port, unsigned int status)
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);
