EHCI_USBSTS
EOWRITE4(sc, EHCI_USBSTS, EHCI_STS_PCD);
status = EHCI_STS_INTRS(EOREAD4(sc, EHCI_USBSTS));
EOWRITE4(sc, EHCI_USBSTS, status); /* acknowledge */
hcr = EOREAD4(sc, EHCI_USBSTS) & EHCI_STS_HCH;
hcr = EOREAD4(sc, EHCI_USBSTS) & EHCI_STS_HCH;
i = EOREAD4(sc, EHCI_USBSTS);