1 files changed, 18 insertions, 11 deletions

diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c
index cc56cb3b3eca..8df0fd824520 100644
--- a/drivers/tty/serial/sh-sci.c
+++ b/drivers/tty/serial/sh-sci.c
@@ -1331,7 +1331,7 @@ static void sci_tx_dma_release(struct sci_port *s)
 	dma_release_channel(chan);
 }
 
-static void sci_submit_rx(struct sci_port *s)
+static int sci_submit_rx(struct sci_port *s, bool port_lock_held)
 {
 	struct dma_chan *chan = s->chan_rx;
 	struct uart_port *port = &s->port;
@@ -1359,19 +1359,22 @@ static void sci_submit_rx(struct sci_port *s)
 	s->active_rx = s->cookie_rx[0];
 
 	dma_async_issue_pending(chan);
-	return;
+	return 0;
 
 fail:
+	/* Switch to PIO */
+	if (!port_lock_held)
+		spin_lock_irqsave(&port->lock, flags);
 	if (i)
 		dmaengine_terminate_async(chan);
 	for (i = 0; i < 2; i++)
 		s->cookie_rx[i] = -EINVAL;
-	s->active_rx = -EINVAL;
-	/* Switch to PIO */
-	spin_lock_irqsave(&port->lock, flags);
+	s->active_rx = 0;
 	s->chan_rx = NULL;
 	sci_start_rx(port);
-	spin_unlock_irqrestore(&port->lock, flags);
+	if (!port_lock_held)
+		spin_unlock_irqrestore(&port->lock, flags);
+	return -EAGAIN;
 }
 
 static void work_fn_tx(struct work_struct *work)
@@ -1491,7 +1494,7 @@ static enum hrtimer_restart rx_timer_fn(struct hrtimer *t)
 	}
 
 	if (port->type == PORT_SCIFA || port->type == PORT_SCIFB)
-		sci_submit_rx(s);
+		sci_submit_rx(s, true);
 
 	/* Direct new serial port interrupts back to CPU */
 	scr = serial_port_in(port, SCSCR);
@@ -1617,7 +1620,7 @@ static void sci_request_dma(struct uart_port *port)
 		s->chan_rx_saved = s->chan_rx = chan;
 
 		if (port->type == PORT_SCIFA || port->type == PORT_SCIFB)
-			sci_submit_rx(s);
+			sci_submit_rx(s, false);
 	}
 }
 
@@ -1666,8 +1669,10 @@ static irqreturn_t sci_rx_interrupt(int irq, void *ptr)
 			disable_irq_nosync(irq);
 			scr |= SCSCR_RDRQE;
 		} else {
+			if (sci_submit_rx(s, false) < 0)
+				goto handle_pio;
+
 			scr &= ~SCSCR_RIE;
-			sci_submit_rx(s);
 		}
 		serial_port_out(port, SCSCR, scr);
 		/* Clear current interrupt */
@@ -1679,6 +1684,8 @@ static irqreturn_t sci_rx_interrupt(int irq, void *ptr)
 
 		return IRQ_HANDLED;
 	}
+
+handle_pio:
 #endif
 
 	if (s->rx_trigger > 1 && s->rx_fifo_timeout > 0) {
@@ -1693,7 +1700,7 @@ static irqreturn_t sci_rx_interrupt(int irq, void *ptr)
 	 * of whether the I_IXOFF is set, otherwise, how is the interrupt
 	 * to be disabled?
 	 */
-	sci_receive_chars(ptr);
+	sci_receive_chars(port);
 
 	return IRQ_HANDLED;
 }
@@ -1749,7 +1756,7 @@ static irqreturn_t sci_er_interrupt(int irq, void *ptr)
 	} else {
 		sci_handle_fifo_overrun(port);
 		if (!s->chan_rx)
-			sci_receive_chars(ptr);
+			sci_receive_chars(port);
 	}
 
 	sci_clear_SCxSR(port, SCxSR_ERROR_CLEAR(port));