1 files changed, 48 insertions, 41 deletions

diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c
index 64bbeb7d7e0c..3cd139752d3f 100644
--- a/drivers/tty/serial/sh-sci.c
+++ b/drivers/tty/serial/sh-sci.c
@@ -838,19 +838,9 @@ static void sci_transmit_chars(struct uart_port *port)
 
 	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
 		uart_write_wakeup(port);
-	if (uart_circ_empty(xmit)) {
+	if (uart_circ_empty(xmit))
 		sci_stop_tx(port);
-	} else {
-		ctrl = serial_port_in(port, SCSCR);
-
-		if (port->type != PORT_SCI) {
-			serial_port_in(port, SCxSR); /* Dummy read */
-			sci_clear_SCxSR(port, SCxSR_TDxE_CLEAR(port));
-		}
 
-		ctrl |= SCSCR_TIE;
-		serial_port_out(port, SCSCR, ctrl);
-	}
 }
 
 /* On SH3, SCIF may read end-of-break as a space->mark char */
@@ -1243,12 +1233,22 @@ static int sci_dma_rx_find_active(struct sci_port *s)
 	return -1;
 }
 
-static void sci_rx_dma_release(struct sci_port *s)
+static void sci_dma_rx_chan_invalidate(struct sci_port *s)
+{
+	unsigned int i;
+
+	s->chan_rx = NULL;
+	for (i = 0; i < ARRAY_SIZE(s->cookie_rx); i++)
+		s->cookie_rx[i] = -EINVAL;
+	s->active_rx = 0;
+}
+
+static void sci_dma_rx_release(struct sci_port *s)
 {
 	struct dma_chan *chan = s->chan_rx_saved;
 
-	s->chan_rx_saved = s->chan_rx = NULL;
-	s->cookie_rx[0] = s->cookie_rx[1] = -EINVAL;
+	s->chan_rx_saved = NULL;
+	sci_dma_rx_chan_invalidate(s);
 	dmaengine_terminate_sync(chan);
 	dma_free_coherent(chan->device->dev, s->buf_len_rx * 2, s->rx_buf[0],
 			  sg_dma_address(&s->sg_rx[0]));
@@ -1264,6 +1264,20 @@ static void start_hrtimer_us(struct hrtimer *hrt, unsigned long usec)
 	hrtimer_start(hrt, t, HRTIMER_MODE_REL);
 }
 
+static void sci_dma_rx_reenable_irq(struct sci_port *s)
+{
+	struct uart_port *port = &s->port;
+	u16 scr;
+
+	/* Direct new serial port interrupts back to CPU */
+	scr = serial_port_in(port, SCSCR);
+	if (port->type == PORT_SCIFA || port->type == PORT_SCIFB) {
+		scr &= ~SCSCR_RDRQE;
+		enable_irq(s->irqs[SCIx_RXI_IRQ]);
+	}
+	serial_port_out(port, SCSCR, scr | SCSCR_RIE);
+}
+
 static void sci_dma_rx_complete(void *arg)
 {
 	struct sci_port *s = arg;
@@ -1313,12 +1327,13 @@ fail:
 	dev_warn(port->dev, "Failed submitting Rx DMA descriptor\n");
 	/* Switch to PIO */
 	spin_lock_irqsave(&port->lock, flags);
-	s->chan_rx = NULL;
-	sci_start_rx(port);
+	dmaengine_terminate_async(chan);
+	sci_dma_rx_chan_invalidate(s);
+	sci_dma_rx_reenable_irq(s);
 	spin_unlock_irqrestore(&port->lock, flags);
 }
 
-static void sci_tx_dma_release(struct sci_port *s)
+static void sci_dma_tx_release(struct sci_port *s)
 {
 	struct dma_chan *chan = s->chan_tx_saved;
 
@@ -1331,7 +1346,7 @@ static void sci_tx_dma_release(struct sci_port *s)
 	dma_release_channel(chan);
 }
 
-static int sci_submit_rx(struct sci_port *s, bool port_lock_held)
+static int sci_dma_rx_submit(struct sci_port *s, bool port_lock_held)
 {
 	struct dma_chan *chan = s->chan_rx;
 	struct uart_port *port = &s->port;
@@ -1367,17 +1382,14 @@ fail:
 		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 = 0;
-	s->chan_rx = NULL;
+	sci_dma_rx_chan_invalidate(s);
 	sci_start_rx(port);
 	if (!port_lock_held)
 		spin_unlock_irqrestore(&port->lock, flags);
 	return -EAGAIN;
 }
 
-static void work_fn_tx(struct work_struct *work)
+static void sci_dma_tx_work_fn(struct work_struct *work)
 {
 	struct sci_port *s = container_of(work, struct sci_port, work_tx);
 	struct dma_async_tx_descriptor *desc;
@@ -1436,7 +1448,7 @@ switch_to_pio:
 	return;
 }
 
-static enum hrtimer_restart rx_timer_fn(struct hrtimer *t)
+static enum hrtimer_restart sci_dma_rx_timer_fn(struct hrtimer *t)
 {
 	struct sci_port *s = container_of(t, struct sci_port, rx_timer);
 	struct dma_chan *chan = s->chan_rx;
@@ -1446,7 +1458,6 @@ static enum hrtimer_restart rx_timer_fn(struct hrtimer *t)
 	unsigned long flags;
 	unsigned int read;
 	int active, count;
-	u16 scr;
 
 	dev_dbg(port->dev, "DMA Rx timed out\n");
 
@@ -1494,15 +1505,9 @@ static enum hrtimer_restart rx_timer_fn(struct hrtimer *t)
 	}
 
 	if (port->type == PORT_SCIFA || port->type == PORT_SCIFB)
-		sci_submit_rx(s, true);
+		sci_dma_rx_submit(s, true);
 
-	/* Direct new serial port interrupts back to CPU */
-	scr = serial_port_in(port, SCSCR);
-	if (port->type == PORT_SCIFA || port->type == PORT_SCIFB) {
-		scr &= ~SCSCR_RDRQE;
-		enable_irq(s->irqs[SCIx_RXI_IRQ]);
-	}
-	serial_port_out(port, SCSCR, scr | SCSCR_RIE);
+	sci_dma_rx_reenable_irq(s);
 
 	spin_unlock_irqrestore(&port->lock, flags);
 
@@ -1580,7 +1585,7 @@ static void sci_request_dma(struct uart_port *port)
 				__func__, UART_XMIT_SIZE,
 				port->state->xmit.buf, &s->tx_dma_addr);
 
-			INIT_WORK(&s->work_tx, work_fn_tx);
+			INIT_WORK(&s->work_tx, sci_dma_tx_work_fn);
 			s->chan_tx_saved = s->chan_tx = chan;
 		}
 	}
@@ -1615,12 +1620,12 @@ static void sci_request_dma(struct uart_port *port)
 		}
 
 		hrtimer_init(&s->rx_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
-		s->rx_timer.function = rx_timer_fn;
+		s->rx_timer.function = sci_dma_rx_timer_fn;
 
 		s->chan_rx_saved = s->chan_rx = chan;
 
 		if (port->type == PORT_SCIFA || port->type == PORT_SCIFB)
-			sci_submit_rx(s, false);
+			sci_dma_rx_submit(s, false);
 	}
 }
 
@@ -1629,9 +1634,9 @@ static void sci_free_dma(struct uart_port *port)
 	struct sci_port *s = to_sci_port(port);
 
 	if (s->chan_tx_saved)
-		sci_tx_dma_release(s);
+		sci_dma_tx_release(s);
 	if (s->chan_rx_saved)
-		sci_rx_dma_release(s);
+		sci_dma_rx_release(s);
 }
 
 static void sci_flush_buffer(struct uart_port *port)
@@ -1669,7 +1674,7 @@ 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)
+			if (sci_dma_rx_submit(s, false) < 0)
 				goto handle_pio;
 
 			scr &= ~SCSCR_RIE;
@@ -2507,14 +2512,16 @@ done:
 			 * center of the last stop bit in sampling clocks.
 			 */
 			int last_stop = bits * 2 - 1;
-			int deviation = min_err * srr * last_stop / 2 / baud;
+			int deviation = DIV_ROUND_CLOSEST(min_err * last_stop *
+							  (int)(srr + 1),
+							  2 * (int)baud);
 
 			if (abs(deviation) >= 2) {
 				/* At least two sampling clocks off at the
 				 * last stop bit; we can increase the error
 				 * margin by shifting the sampling point.
 				 */
-				int shift = min(-8, max(7, deviation / 2));
+				int shift = clamp(deviation / 2, -8, 7);
 
 				hssrr |= (shift << HSCIF_SRHP_SHIFT) &
 					 HSCIF_SRHP_MASK;