serial: omap: Make context_loss_cnt signed

get_context_loss_count returns an int however it is stored in
unsigned integer context_loss_cnt . This patch tries to make
context_loss_cnt int. So that in case of errors the value
(which may be negative) is not interpreted wrongly.

In serial_omap_runtime_resume in case of errors returned by
get_context_loss_count print a warning and do a restore.

Signed-off-by: Shubhrajyoti D <shubhrajyoti@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/omap-serial.c

@@ -96,7 +96,7 @@ struct uart_omap_port {
 	unsigned char		msr_saved_flags;
 	char			name[20];
 	unsigned long		port_activity;
-	u32			context_loss_cnt;
+	int			context_loss_cnt;
 	u32			errata;
 	u8			wakeups_enabled;
 	unsigned int		irq_pending:1;
@@ -1556,11 +1556,15 @@ static int serial_omap_runtime_resume(struct device *dev)
 {
 	struct uart_omap_port *up = dev_get_drvdata(dev);
 
-	u32 loss_cnt = serial_omap_get_context_loss_count(up);
+	int loss_cnt = serial_omap_get_context_loss_count(up);
 
-	if (up->context_loss_cnt != loss_cnt)
+	if (loss_cnt < 0) {
+		dev_err(dev, "serial_omap_get_context_loss_count failed : %d\n",
+			loss_cnt);
 		serial_omap_restore_context(up);
-
+	} else if (up->context_loss_cnt != loss_cnt) {
+		serial_omap_restore_context(up);
+	}
 	up->latency = up->calc_latency;
 	schedule_work(&up->qos_work);