serial: sh-sci: Clear (H)SCIF timeout and overrun during reset

Add the missing timeout bit definition for (H)SCIF.
Clear the timeout and overrun flag bits during UART reset, cfr. the
initialization flowchart in the datasheet.
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/sh-sci.c

@@ -2156,6 +2156,11 @@ static void sci_reset(struct uart_port *port)
 	sci_clear_SCxSR(port,
 			SCxSR_RDxF_CLEAR(port) & SCxSR_ERROR_CLEAR(port) &
 			SCxSR_BREAK_CLEAR(port));
+	if (sci_getreg(port, SCLSR)->size) {
+		status = serial_port_in(port, SCLSR);
+		status &= ~(SCLSR_TO | SCLSR_ORER);
+		serial_port_out(port, SCLSR, status);
+	}
 }
 
 static void sci_set_termios(struct uart_port *port, struct ktermios *termios,

drivers/tty/serial/sh-sci.h

@@ -105,6 +105,7 @@ enum {
 #define SCFCR_LOOP	BIT(0)	/* Loopback Test */
 
 /* SCLSR (Line Status Register) on (H)SCIF */
+#define SCLSR_TO	BIT(2)	/* Timeout */
 #define SCLSR_ORER	BIT(0)	/* Overrun Error */
 
 /* SCSPTR (Serial Port Register), optional */