1 files changed, 8 insertions, 29 deletions

diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index f776b3eafb96..d2f3310abe54 100644
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -552,30 +552,11 @@ static unsigned int serial_icr_read(struct uart_8250_port *up, int offset)
  */
 static void serial8250_clear_fifos(struct uart_8250_port *p)
 {
-	unsigned char fcr;
-	unsigned char clr_mask = UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT;
-
 	if (p->capabilities & UART_CAP_FIFO) {
-		/*
-		 * Make sure to avoid changing FCR[7:3] and ENABLE_FIFO bits.
-		 * In case ENABLE_FIFO is not set, there is nothing to flush
-		 * so just return. Furthermore, on certain implementations of
-		 * the 8250 core, the FCR[7:3] bits may only be changed under
-		 * specific conditions and changing them if those conditions
-		 * are not met can have nasty side effects. One such core is
-		 * the 8250-omap present in TI AM335x.
-		 */
-		fcr = serial_in(p, UART_FCR);
-
-		/* FIFO is not enabled, there's nothing to clear. */
-		if (!(fcr & UART_FCR_ENABLE_FIFO))
-			return;
-
-		fcr |= clr_mask;
-		serial_out(p, UART_FCR, fcr);
-
-		fcr &= ~clr_mask;
-		serial_out(p, UART_FCR, fcr);
+		serial_out(p, UART_FCR, UART_FCR_ENABLE_FIFO);
+		serial_out(p, UART_FCR, UART_FCR_ENABLE_FIFO |
+			       UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT);
+		serial_out(p, UART_FCR, 0);
 	}
 }
 
@@ -1467,7 +1448,7 @@ static void __do_stop_tx_rs485(struct uart_8250_port *p)
 	 * Enable previously disabled RX interrupts.
 	 */
 	if (!(p->port.rs485.flags & SER_RS485_RX_DURING_TX)) {
-		serial8250_clear_fifos(p);
+		serial8250_clear_and_reinit_fifos(p);
 
 		p->ier |= UART_IER_RLSI | UART_IER_RDI;
 		serial_port_out(&p->port, UART_IER, p->ier);
@@ -1755,7 +1736,7 @@ void serial8250_read_char(struct uart_8250_port *up, unsigned char lsr)
 		else if (lsr & UART_LSR_FE)
 			flag = TTY_FRAME;
 	}
-	if (uart_handle_sysrq_char(port, ch))
+	if (uart_prepare_sysrq_char(port, ch))
 		return;
 
 	uart_insert_char(port, lsr, UART_LSR_OE, ch, flag);
@@ -1897,7 +1878,7 @@ int serial8250_handle_irq(struct uart_port *port, unsigned int iir)
 	if ((!up->dma || up->dma->tx_err) && (status & UART_LSR_THRE))
 		serial8250_tx_chars(up);
 
-	spin_unlock_irqrestore(&port->lock, flags);
+	uart_unlock_and_check_sysrq(port, flags);
 	return 1;
 }
 EXPORT_SYMBOL_GPL(serial8250_handle_irq);
@@ -3258,9 +3239,7 @@ void serial8250_console_write(struct uart_8250_port *up, const char *s,
 
 	serial8250_rpm_get(up);
 
-	if (port->sysrq)
-		locked = 0;
-	else if (oops_in_progress)
+	if (oops_in_progress)
 		locked = spin_trylock_irqsave(&port->lock, flags);
 	else
 		spin_lock_irqsave(&port->lock, flags);