1 files changed, 28 insertions, 2 deletions

diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c
index 9ae024025ff3..6800f5f26241 100644
--- a/drivers/tty/serial/amba-pl011.c
+++ b/drivers/tty/serial/amba-pl011.c
@@ -159,6 +159,7 @@ struct uart_amba_port {
 	unsigned int		fifosize;	/* vendor-specific */
 	unsigned int		lcrh_tx;	/* vendor-specific */
 	unsigned int		lcrh_rx;	/* vendor-specific */
+	unsigned int		old_cr;		/* state during shutdown */
 	bool			autorts;
 	char			type[12];
 	bool			interrupt_may_hang; /* vendor-specific */
@@ -1411,7 +1412,9 @@ static int pl011_startup(struct uart_port *port)
 	while (readw(uap->port.membase + UART01x_FR) & UART01x_FR_BUSY)
 		barrier();
 
-	cr = UART01x_CR_UARTEN | UART011_CR_RXE | UART011_CR_TXE;
+	/* restore RTS and DTR */
+	cr = uap->old_cr & (UART011_CR_RTS | UART011_CR_DTR);
+	cr |= UART01x_CR_UARTEN | UART011_CR_RXE | UART011_CR_TXE;
 	writew(cr, uap->port.membase + UART011_CR);
 
 	/* Clear pending error interrupts */
@@ -1469,6 +1472,7 @@ static void pl011_shutdown_channel(struct uart_amba_port *uap,
 static void pl011_shutdown(struct uart_port *port)
 {
 	struct uart_amba_port *uap = (struct uart_amba_port *)port;
+	unsigned int cr;
 
 	/*
 	 * disable all interrupts
@@ -1488,9 +1492,16 @@ static void pl011_shutdown(struct uart_port *port)
 
 	/*
 	 * disable the port
+	 * disable the port. It should not disable RTS and DTR.
+	 * Also RTS and DTR state should be preserved to restore
+	 * it during startup().
 	 */
 	uap->autorts = false;
-	writew(UART01x_CR_UARTEN | UART011_CR_TXE, uap->port.membase + UART011_CR);
+	cr = readw(uap->port.membase + UART011_CR);
+	uap->old_cr = cr;
+	cr &= UART011_CR_RTS | UART011_CR_DTR;
+	cr |= UART01x_CR_UARTEN | UART011_CR_TXE;
+	writew(cr, uap->port.membase + UART011_CR);
 
 	/*
 	 * disable break condition and fifos
@@ -1740,9 +1751,19 @@ pl011_console_write(struct console *co, const char *s, unsigned int count)
 {
 	struct uart_amba_port *uap = amba_ports[co->index];
 	unsigned int status, old_cr, new_cr;
+	unsigned long flags;
+	int locked = 1;
 
 	clk_enable(uap->clk);
 
+	local_irq_save(flags);
+	if (uap->port.sysrq)
+		locked = 0;
+	else if (oops_in_progress)
+		locked = spin_trylock(&uap->port.lock);
+	else
+		spin_lock(&uap->port.lock);
+
 	/*
 	 *	First save the CR then disable the interrupts
 	 */
@@ -1762,6 +1783,10 @@ pl011_console_write(struct console *co, const char *s, unsigned int count)
 	} while (status & UART01x_FR_BUSY);
 	writew(old_cr, uap->port.membase + UART011_CR);
 
+	if (locked)
+		spin_unlock(&uap->port.lock);
+	local_irq_restore(flags);
+
 	clk_disable(uap->clk);
 }
 
@@ -1905,6 +1930,7 @@ static int pl011_probe(struct amba_device *dev, const struct amba_id *id)
 	uap->vendor = vendor;
 	uap->lcrh_rx = vendor->lcrh_rx;
 	uap->lcrh_tx = vendor->lcrh_tx;
+	uap->old_cr = 0;
 	uap->fifosize = vendor->fifosize;
 	uap->interrupt_may_hang = vendor->interrupt_may_hang;
 	uap->port.dev = &dev->dev;