RISCV_IOMMU_CQB
q->head_off = (uint32_t)base - RISCV_IOMMU_CQB + RISCV_IOMMU_CQH;
q->tail_off = (uint32_t)base - RISCV_IOMMU_CQB + RISCV_IOMMU_CQT;
error = riscv_iommu_init_queue(sc, &sc->cq, RISCV_IOMMU_CQB,
#define QUEUE_HEAD(q) ((q)->csr + RISCV_IOMMU_CQH - RISCV_IOMMU_CQB)
#define QUEUE_TAIL(q) ((q)->csr + RISCV_IOMMU_CQT - RISCV_IOMMU_CQB)