Q_DESC_SIZE
((uint32_t)qp->desc_ring_bus_addr) + (Q_DESC_SIZE * qp->cq_tail));
i = (headlo - (uint32_t)qp->desc_ring_bus_addr) / Q_DESC_SIZE;
(uint32_t)qp->desc_ring_bus_addr + (idx * Q_DESC_SIZE));
idx = (headlo - (uint32_t)qp->desc_ring_bus_addr) / Q_DESC_SIZE;