+ /*
+ * Allocate usb 3.0 device context.
+ * USB 3.0 (xHCI) protocol tries to allocate device slot
+ * and related data structures first. This call does that.
+ * Refer to sec 4.3.2 in xHCI spec rev1.0
+ */
+ if (usb_alloc_device(dev)) {
+ printf("Cannot allocate device context to get SLOT_ID\n");
+ return -1;
+ }
+