find_cap
struct ds_cap_state *cp = find_cap(dp, dpkt->handle);
struct ds_cap_state *cp = find_cap(dp, ap->handle);
struct ds_cap_state *cp = find_cap(dp, np->handle);
cap = find_cap(bus, slot, func,
return find_cap(bus, slot, func, PCI_CAP_ID_EHCI_DEBUG);