FIFOHANDLESIZE
return nr_entry * sizeof(u64) + FIFOHANDLESIZE;
driver_ccb->ccb_u1.send_fifobar = dma_va + FIFOHANDLESIZE;
ilo_ccb->ccb_u1.send_fifobar_pa = dma_pa + FIFOHANDLESIZE;
driver_ccb->ccb_u3.recv_fifobar = dma_va + FIFOHANDLESIZE;
ilo_ccb->ccb_u3.recv_fifobar_pa = dma_pa + FIFOHANDLESIZE;
((struct fifo *)(((char *)(_fifo)) - FIFOHANDLESIZE))