4.16-stable review patch. If anyone has any objections, please let me know.
------------------
From: Gabriel Matni <gabriel.matni@xxxxxxxx>
[ Upstream commit c685af1108d7c303f0b901413405d68eaeac4477 ]
Fixes missing characters on kernel console at low baud rates (i.e.9600).
The driver should poll TX_RDY or TX_FIFO_EMP instead of TX_EMP to ensure
that the transmitter holding register (THR) is ready to receive a new byte.
TX_EMP tells us when it is possible to send a break sequence via
SND_BRK_SEQ. While this also indicates that both the THR and the TSR are
empty, it does not guarantee that a new byte can be written just yet.
Fixes: 30530791a7a0 ("serial: mvebu-uart: initial support for Armada-3700 serial port")
Reviewed-by: Miquel Raynal <miquel.raynal@xxxxxxxxxxx>
Acked-by: Gregory CLEMENT <gregory.clement@xxxxxxxxxxx>
Signed-off-by: Gabriel Matni <gabriel.matni@xxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/tty/serial/mvebu-uart.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/tty/serial/mvebu-uart.c
+++ b/drivers/tty/serial/mvebu-uart.c
@@ -617,7 +617,7 @@ static void wait_for_xmitr(struct uart_p
u32 val;
readl_poll_timeout_atomic(port->membase + UART_STAT, val,
- (val & STAT_TX_EMP), 1, 10000);
+ (val & STAT_TX_RDY(port)), 1, 10000);
}
static void mvebu_uart_console_putchar(struct uart_port *port, int ch)
