serial: sh-sci: Do not start transfers from sci_startup()
FIFO reset is done in sci_reset(), called from sci_set_termios(), while
sci_start_tx() and sci_start_rx() are called before, from sci_startup().
However, starting transfers before the UART's FIFOs have been reset may
cause reading of stale data.
Remove the calls to sci_start_tx() and sci_start_rx() from sci_startup()
to fix this.
Transfers are still started when needed:
- sci_start_rx() is called from sci_set_termios() after FIFO reset, if
the CREAD flag is set,
- sci_start_tx() is called from uart_change_speed() immediately
thereafter, if transmission is enabled.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c
index d9cb0d7..d88c84cd 100644
--- a/drivers/tty/serial/sh-sci.c
+++ b/drivers/tty/serial/sh-sci.c
@@ -1972,7 +1972,6 @@
static int sci_startup(struct uart_port *port)
{
struct sci_port *s = to_sci_port(port);
- unsigned long flags;
int ret;
dev_dbg(port->dev, "%s(%d)\n", __func__, port->line);
@@ -1983,11 +1982,6 @@
sci_request_dma(port);
- spin_lock_irqsave(&port->lock, flags);
- sci_start_tx(port);
- sci_start_rx(port);
- spin_unlock_irqrestore(&port->lock, flags);
-
return 0;
}