USB: Add hub descriptor update hook for xHCI

Add a hook for updating xHCI internal structures after khubd fetches the
hub descriptor and sets up the hub's TT information.  The xHCI driver must
update the internal structures before devices under the hub can be
enumerated.
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/core/hcd.h

@@ -267,6 +267,11 @@ struct hc_driver {
 	void	(*reset_bandwidth)(struct usb_hcd *, struct usb_device *);
 		/* Returns the hardware-chosen device address */
 	int	(*address_device)(struct usb_hcd *, struct usb_device *udev);
+		/* Notifies the HCD after a hub descriptor is fetched.
+		 * Will block.
+		 */
+	int	(*update_hub_device)(struct usb_hcd *, struct usb_device *hdev,
+			struct usb_tt *tt, gfp_t mem_flags);
 };
 
 extern int usb_hcd_link_urb_to_ep(struct usb_hcd *hcd, struct urb *urb);

drivers/usb/core/hub.c

@@ -860,6 +860,7 @@ static int hub_post_reset(struct usb_interface *intf)
 static int hub_configure(struct usb_hub *hub,
 	struct usb_endpoint_descriptor *endpoint)
 {
+	struct usb_hcd *hcd;
 	struct usb_device *hdev = hub->hdev;
 	struct device *hub_dev = hub->intfdev;
 	u16 hubstatus, hubchange;
@@ -1061,6 +1062,19 @@ static int hub_configure(struct usb_hub *hub,
 		dev_dbg(hub_dev, "%umA bus power budget for each child\n",
 				hub->mA_per_port);
 
+	/* Update the HCD's internal representation of this hub before khubd
+	 * starts getting port status changes for devices under the hub.
+	 */
+	hcd = bus_to_hcd(hdev->bus);
+	if (hcd->driver->update_hub_device) {
+		ret = hcd->driver->update_hub_device(hcd, hdev,
+				&hub->tt, GFP_KERNEL);
+		if (ret < 0) {
+			message = "can't update HCD hub info";
+			goto fail;
+		}
+	}
+
 	ret = hub_hub_status(hub, &hubstatus, &hubchange);
 	if (ret < 0) {
 		message = "can't get hub status";

drivers/usb/host/xhci-pci.c

@@ -136,6 +136,7 @@ static const struct hc_driver xhci_pci_hc_driver = {
 	.check_bandwidth =	xhci_check_bandwidth,
 	.reset_bandwidth =	xhci_reset_bandwidth,
 	.address_device =	xhci_address_device,
+	.update_hub_device =	xhci_update_hub_device,
 
 	/*
 	 * scheduling support