[PATCH 5.12 095/296] serial: tegra: Fix a mask operation that is always true

Greg Kroah-Hartman
2021-05-31T16:20:09Z

From: Colin Ian King <colin.king@canonical.com>

commit 3ddb4ce1e6e3bd112778ab93bbd9092f23a878ec upstream.

Currently the expression lsr | UART_LSR_TEMT is always true and
this seems suspect. I believe the intent was to mask lsr with UART_LSR_TEMT
to check that bit, so the expression should be using the & operator
instead. Fix this.

Fixes: b9c2470fb150 ("serial: tegra: flush the RX fifo on frame error")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20210426105514.23268-1-colin.king@canonical.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/tty/serial/serial-tegra.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/tty/serial/serial-tegra.c
+++ b/drivers/tty/serial/serial-tegra.c
@@ -338,7 +338,7 @@ static void tegra_uart_fifo_reset(struct

do {
lsr = tegra_uart_read(tup, UART_LSR);
- if ((lsr | UART_LSR_TEMT) && !(lsr & UART_LSR_DR))
+ if ((lsr & UART_LSR_TEMT) && !(lsr & UART_LSR_DR))
break;
udelay(1);
} while (--tmout);