MPI_DOORBELL_FUNCTION_SHIFT   50 dev/ic/mpireg.h #define  MPI_DOORBELL_FUNCTION_MASK	(0xff << MPI_DOORBELL_FUNCTION_SHIFT)
MPI_DOORBELL_FUNCTION_SHIFT   52 dev/ic/mpireg.h     (((x) << MPI_DOORBELL_FUNCTION_SHIFT) & MPI_DOORBELL_FUNCTION_MASK)