Q_HEAD
riscv_iommu_writel(queue->iommu, Q_HEAD(queue), 0);
riscv_iommu_writel(queue->iommu, Q_HEAD(queue), Q_ITEM(queue, head));
if (riscv_iommu_readl_timeout(queue->iommu, Q_HEAD(queue), head,
if (riscv_iommu_readl_timeout(queue->iommu, Q_HEAD(queue), head,