serial: sh-sci: Fix R-Car SCIF and HSCIF overrun handling

When fifo overrun happened, the interrupt status refers to
SCLSR register in R-Car SCIF and HSCIF.
Thus, overrun handling takes SCLSR register into account.

Signed-off-by: Hisashi Nakamura <hisashi.nakamura.ak@renesas.com>
Signed-off-by: Yoshihiro Kaneko <ykaneko0929@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/sh-sci.c

@@ -997,12 +997,15 @@ static inline unsigned long port_rx_irq_mask(struct uart_port *port)
 static irqreturn_t sci_mpxed_interrupt(int irq, void *ptr)
 {
 	unsigned short ssr_status, scr_status, err_enabled;
+	unsigned short slr_status = 0;
 	struct uart_port *port = ptr;
 	struct sci_port *s = to_sci_port(port);
 	irqreturn_t ret = IRQ_NONE;
 
 	ssr_status = serial_port_in(port, SCxSR);
 	scr_status = serial_port_in(port, SCSCR);
+	if (port->type == PORT_SCIF || port->type == PORT_HSCIF)
+		slr_status = serial_port_in(port, SCLSR);
 	err_enabled = scr_status & port_rx_irq_mask(port);
 
 	/* Tx Interrupt */
@@ -1015,8 +1018,11 @@ static irqreturn_t sci_mpxed_interrupt(int irq, void *ptr)
 	 * DR flags
 	 */
 	if (((ssr_status & SCxSR_RDxF(port)) || s->chan_rx) &&
-	    (scr_status & SCSCR_RIE))
+	    (scr_status & SCSCR_RIE)) {
+		if (port->type == PORT_SCIF || port->type == PORT_HSCIF)
+			sci_handle_fifo_overrun(port);
 		ret = sci_rx_interrupt(irq, ptr);
+	}
 
 	/* Error Interrupt */
 	if ((ssr_status & SCxSR_ERRORS(port)) && err_enabled)
@@ -1026,6 +1032,12 @@ static irqreturn_t sci_mpxed_interrupt(int irq, void *ptr)
 	if ((ssr_status & SCxSR_BRK(port)) && err_enabled)
 		ret = sci_br_interrupt(irq, ptr);
 
+	/* Overrun Interrupt */
+	if (port->type == PORT_SCIF || port->type == PORT_HSCIF) {
+		if (slr_status & 0x01)
+			sci_handle_fifo_overrun(port);
+	}
+
 	return ret;
 }