1 files changed, 42 insertions, 23 deletions

diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c
index 919706988c72..cc0504f30a1d 100644
--- a/drivers/tty/serial/sh-sci.c
+++ b/drivers/tty/serial/sh-sci.c
@@ -2391,6 +2391,27 @@ done:
 
 	uart_update_timeout(port, termios->c_cflag, baud);
 
+	/* byte size and parity */
+	switch (termios->c_cflag & CSIZE) {
+	case CS5:
+		bits = 7;
+		break;
+	case CS6:
+		bits = 8;
+		break;
+	case CS7:
+		bits = 9;
+		break;
+	default:
+		bits = 10;
+		break;
+	}
+
+	if (termios->c_cflag & CSTOPB)
+		bits++;
+	if (termios->c_cflag & PARENB)
+		bits++;
+
 	if (best_clk >= 0) {
 		if (port->type == PORT_SCIFA || port->type == PORT_SCIFB)
 			switch (srr + 1) {
@@ -2407,8 +2428,27 @@ done:
 		serial_port_out(port, SCSCR, scr_val | s->hscif_tot);
 		serial_port_out(port, SCSMR, smr_val);
 		serial_port_out(port, SCBRR, brr);
-		if (sci_getreg(port, HSSRR)->size)
-			serial_port_out(port, HSSRR, srr | HSCIF_SRE);
+		if (sci_getreg(port, HSSRR)->size) {
+			unsigned int hssrr = srr | HSCIF_SRE;
+			/* Calculate deviation from intended rate at the
+			 * center of the last stop bit in sampling clocks.
+			 */
+			int last_stop = bits * 2 - 1;
+			int deviation = min_err * srr * last_stop / 2 / 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));
+
+				hssrr |= (shift << HSCIF_SRHP_SHIFT) &
+					 HSCIF_SRHP_MASK;
+				hssrr |= HSCIF_SRDE;
+			}
+			serial_port_out(port, HSSRR, hssrr);
+		}
 
 		/* Wait one bit interval */
 		udelay((1000000 + (baud - 1)) / baud);
@@ -2475,27 +2515,6 @@ done:
 	 * value obtained by this formula is too small. Therefore, if the value
 	 * is smaller than 20ms, use 20ms as the timeout value for DMA.
 	 */
-	/* byte size and parity */
-	switch (termios->c_cflag & CSIZE) {
-	case CS5:
-		bits = 7;
-		break;
-	case CS6:
-		bits = 8;
-		break;
-	case CS7:
-		bits = 9;
-		break;
-	default:
-		bits = 10;
-		break;
-	}
-
-	if (termios->c_cflag & CSTOPB)
-		bits++;
-	if (termios->c_cflag & PARENB)
-		bits++;
-
 	s->rx_frame = (10000 * bits) / (baud / 100);
 #ifdef CONFIG_SERIAL_SH_SCI_DMA
 	s->rx_timeout = s->buf_len_rx * 2 * s->rx_frame;