Hi sripathi,
Scell sceduling is based on Scell RRM report. Pcell indicates the starting symbol of UE data as part of DCI in Pcell. Scell reports its starting symbol based on its CFI value(means PDCCH capacity)..
Main interface between Scell and Pcell is RRM. It is implmentation specific that hoe you want to know Scell CFI . One way is through RRM.