xHCI: test and clear RWC bit

Introduce xhci_test_and_clear_bit() to clear RWC bit in PORTSC register.

Signed-off-by: Andiry Xu <andiry.xu@amd.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/usb/host/xhci-hub.c b/drivers/usb/host/xhci-hub.c
index ef03c18..d7be6d7 100644
--- a/drivers/usb/host/xhci-hub.c
+++ b/drivers/usb/host/xhci-hub.c
@@ -404,6 +404,20 @@
 	xhci_writel(xhci, temp, port_array[port_id]);
 }
 
+/* Test and clear port RWC bit */
+void xhci_test_and_clear_bit(struct xhci_hcd *xhci, __le32 __iomem **port_array,
+				int port_id, u32 port_bit)
+{
+	u32 temp;
+
+	temp = xhci_readl(xhci, port_array[port_id]);
+	if (temp & port_bit) {
+		temp = xhci_port_state_to_neutral(temp);
+		temp |= port_bit;
+		xhci_writel(xhci, temp, port_array[port_id]);
+	}
+}
+
 int xhci_hub_control(struct usb_hcd *hcd, u16 typeReq, u16 wValue,
 		u16 wIndex, char *buf, u16 wLength)
 {
@@ -924,12 +938,8 @@
 			spin_lock_irqsave(&xhci->lock, flags);
 
 			/* Clear PLC */
-			temp = xhci_readl(xhci, port_array[port_index]);
-			if (temp & PORT_PLC) {
-				temp = xhci_port_state_to_neutral(temp);
-				temp |= PORT_PLC;
-				xhci_writel(xhci, temp, port_array[port_index]);
-			}
+			xhci_test_and_clear_bit(xhci, port_array, port_index,
+						PORT_PLC);
 
 			slot_id = xhci_find_slot_id_by_port(hcd,
 					xhci, port_index + 1);