Tx'ing does not correctly account Tx'ed characters into icount.tx.
Using uart_xmit_advance() fixes the problem.

Fixes: 2d908b38d409 ("serial: Add Tegra Combined UART driver")
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
---
 drivers/tty/serial/tegra-tcu.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/tty/serial/tegra-tcu.c b/drivers/tty/serial/tegra-tcu.c
index 4877c54c613d..889b701ba7c6 100644
--- a/drivers/tty/serial/tegra-tcu.c
+++ b/drivers/tty/serial/tegra-tcu.c
@@ -101,7 +101,7 @@ static void tegra_tcu_uart_start_tx(struct uart_port *port)
 			break;
 
 		tegra_tcu_write(tcu, &xmit->buf[xmit->tail], count);
-		xmit->tail = (xmit->tail + count) & (UART_XMIT_SIZE - 1);
+		uart_xmit_advance(port, count);
 	}
 
 	uart_write_wakeup(port);
-- 
2.30.2