serial: 8250_of: Add IO space support

Currently the 8250_of driver only supports MEM IO type
accesses.

Some development boards (Huawei D03, specifically) require
IO space access for 8250-compatible OF driver support, so
add it.

The modification is quite simple: just set the port iotype
and associated flags depending on the device address
resource type.
Signed-off-by: John Garry <john.garry@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/8250/8250_of.c

@@ -92,7 +92,14 @@ static int of_platform_serial_setup(struct platform_device *ofdev,
 		goto err_unprepare;
 	}
 
+	port->flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_FIXED_PORT |
+				  UPF_FIXED_TYPE;
 	spin_lock_init(&port->lock);
+
+	if (resource_type(&resource) == IORESOURCE_IO) {
+		port->iotype = UPIO_PORT;
+		port->iobase = resource.start;
+	} else {
 		port->mapbase = resource.start;
 		port->mapsize = resource_size(&resource);
 
@@ -100,20 +107,6 @@ static int of_platform_serial_setup(struct platform_device *ofdev,
 		if (of_property_read_u32(np, "reg-offset", &prop) == 0)
 			port->mapbase += prop;
 
-	/* Check for registers offset within the devices address range */
-	if (of_property_read_u32(np, "reg-shift", &prop) == 0)
-		port->regshift = prop;
-
-	/* Check for fifo size */
-	if (of_property_read_u32(np, "fifo-size", &prop) == 0)
-		port->fifosize = prop;
-
-	/* Check for a fixed line number */
-	ret = of_alias_get_id(np, "serial");
-	if (ret >= 0)
-		port->line = ret;
-
-	port->irq = irq_of_parse_and_map(np, 0);
 		port->iotype = UPIO_MEM;
 		if (of_property_read_u32(np, "reg-io-width", &prop) == 0) {
 			switch (prop) {
@@ -134,6 +127,23 @@ static int of_platform_serial_setup(struct platform_device *ofdev,
 				goto err_dispose;
 			}
 		}
+		port->flags |= UPF_IOREMAP;
+	}
+
+	/* Check for registers offset within the devices address range */
+	if (of_property_read_u32(np, "reg-shift", &prop) == 0)
+		port->regshift = prop;
+
+	/* Check for fifo size */
+	if (of_property_read_u32(np, "fifo-size", &prop) == 0)
+		port->fifosize = prop;
+
+	/* Check for a fixed line number */
+	ret = of_alias_get_id(np, "serial");
+	if (ret >= 0)
+		port->line = ret;
+
+	port->irq = irq_of_parse_and_map(np, 0);
 
 	info->rst = devm_reset_control_get_optional_shared(&ofdev->dev, NULL);
 	if (IS_ERR(info->rst)) {
@@ -147,8 +157,6 @@ static int of_platform_serial_setup(struct platform_device *ofdev,
 
 	port->type = type;
 	port->uartclk = clk;
-	port->flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_IOREMAP
-		| UPF_FIXED_PORT | UPF_FIXED_TYPE;
 	port->irqflags |= IRQF_SHARED;
 
 	if (of_property_read_bool(np, "no-loopback-test"))