1 files changed, 31 insertions, 6 deletions

diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c
index a81ff7bc5fa1..c3db16b7afa1 100644
--- a/drivers/serial/8250.c
+++ b/drivers/serial/8250.c
@@ -2408,6 +2408,21 @@ serial8250_set_termios(struct uart_port *port, struct ktermios *termios,
 }
 
 static void
+serial8250_set_ldisc(struct uart_port *port)
+{
+	int line = port->line;
+
+	if (line >= port->state->port.tty->driver->num)
+		return;
+
+	if (port->state->port.tty->ldisc->ops->num == N_PPS) {
+		port->flags |= UPF_HARDPPS_CD;
+		serial8250_enable_ms(port);
+	} else
+		port->flags &= ~UPF_HARDPPS_CD;
+}
+
+static void
 serial8250_pm(struct uart_port *port, unsigned int state,
 	      unsigned int oldstate)
 {
@@ -2628,6 +2643,7 @@ static struct uart_ops serial8250_pops = {
 	.startup	= serial8250_startup,
 	.shutdown	= serial8250_shutdown,
 	.set_termios	= serial8250_set_termios,
+	.set_ldisc	= serial8250_set_ldisc,
 	.pm		= serial8250_pm,
 	.type		= serial8250_type,
 	.release_port	= serial8250_release_port,
@@ -2690,6 +2706,15 @@ static void __init serial8250_isa_init_ports(void)
 	}
 }
 
+static void
+serial8250_init_fixed_type_port(struct uart_8250_port *up, unsigned int type)
+{
+	up->port.type = type;
+	up->port.fifosize = uart_config[type].fifo_size;
+	up->capabilities = uart_config[type].flags;
+	up->tx_loadsz = uart_config[type].tx_loadsz;
+}
+
 static void __init
 serial8250_register_ports(struct uart_driver *drv, struct device *dev)
 {
@@ -2706,6 +2731,10 @@ serial8250_register_ports(struct uart_driver *drv, struct device *dev)
 		struct uart_8250_port *up = &serial8250_ports[i];
 
 		up->port.dev = dev;
+
+		if (up->port.flags & UPF_FIXED_TYPE)
+			serial8250_init_fixed_type_port(up, up->port.type);
+
 		uart_add_one_port(drv, &up->port);
 	}
 }
@@ -3118,12 +3147,8 @@ int serial8250_register_port(struct uart_port *port)
 		if (port->dev)
 			uart->port.dev = port->dev;
 
-		if (port->flags & UPF_FIXED_TYPE) {
-			uart->port.type = port->type;
-			uart->port.fifosize = uart_config[port->type].fifo_size;
-			uart->capabilities = uart_config[port->type].flags;
-			uart->tx_loadsz = uart_config[port->type].tx_loadsz;
-		}
+		if (port->flags & UPF_FIXED_TYPE)
+			serial8250_init_fixed_type_port(uart, port->type);
 
 		set_io_from_upio(&uart->port);
 		/* Possibly override default I/O functions.  */