From: Narendra Hadke <nhadke@marvell.com> stable inclusion from stable-v5.10.137 commit 3bdda8656a1b74879f6b3889133ccc85decb0b3f category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I60PLB Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- commit a7209541239e5dd44d981289e5f9059222d40fd1 upstream. For mvebu uart2, error bits are not cleared on buffer read. This causes interrupt loop and system hang. Cc: stable@vger.kernel.org Reviewed-by: Yi Guo <yi.guo@cavium.com> Reviewed-by: Nadav Haklai <nadavh@marvell.com> Signed-off-by: Narendra Hadke <nhadke@marvell.com> Signed-off-by: Pali Rohár <pali@kernel.org> Link: https://lore.kernel.org/r/20220726091221.12358-1-pali@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com> Reviewed-by: Wei Li <liwei391@huawei.com> --- drivers/tty/serial/mvebu-uart.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/drivers/tty/serial/mvebu-uart.c b/drivers/tty/serial/mvebu-uart.c index e941f57de953..bbf1b0b37b11 100644 --- 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 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)) { @@ -250,6 +251,16 @@ 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); -- 2.20.1