From: Pali Rohár pali@kernel.org
stable inclusion from linux-4.19.209 commit 4a319dd66f497bb5e8441950af48c845c0670849
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commit 74e1eb3b4a1ef2e564b4bdeb6e92afe844e900de upstream.
Driver's tx_empty callback should signal when the transmit shift register is empty. So when the last character has been sent.
STAT_TX_FIFO_EMP bit signals only that HW transmit FIFO is empty, which happens when the last byte is loaded into transmit shift register.
STAT_TX_EMP bit signals when the both HW transmit FIFO and transmit shift register are empty.
So replace STAT_TX_FIFO_EMP check by STAT_TX_EMP in mvebu_uart_tx_empty() callback function.
Fixes: 30530791a7a0 ("serial: mvebu-uart: initial support for Armada-3700 serial port") Cc: stable stable@vger.kernel.org Signed-off-by: Pali Rohár pali@kernel.org Link: https://lore.kernel.org/r/20210911132017.25505-1-pali@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Acked-by: Jason Yan yanaijie@huawei.com Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- drivers/tty/serial/mvebu-uart.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/tty/serial/mvebu-uart.c b/drivers/tty/serial/mvebu-uart.c index 170e446a2f625..494e476ac8db9 100644 --- a/drivers/tty/serial/mvebu-uart.c +++ b/drivers/tty/serial/mvebu-uart.c @@ -162,7 +162,7 @@ static unsigned int mvebu_uart_tx_empty(struct uart_port *port) st = readl(port->membase + UART_STAT); spin_unlock_irqrestore(&port->lock, flags);
- return (st & STAT_TX_FIFO_EMP) ? TIOCSER_TEMT : 0; + return (st & STAT_TX_EMP) ? TIOCSER_TEMT : 0; }
static unsigned int mvebu_uart_get_mctrl(struct uart_port *port)