+/*
+ * Disable Queued Invalidation interface.
+ */
+void dmar_disable_qi(struct intel_iommu *iommu)
+{
+ unsigned long flags;
+ u32 sts;
+ cycles_t start_time = get_cycles();
+
+ if (!ecap_qis(iommu->ecap))
+ return;
+
+ spin_lock_irqsave(&iommu->register_lock, flags);
+
+ sts = dmar_readq(iommu->reg + DMAR_GSTS_REG);
+ if (!(sts & DMA_GSTS_QIES))
+ goto end;
+
+ /*
+ * Give a chance to HW to complete the pending invalidation requests.
+ */
+ while ((readl(iommu->reg + DMAR_IQT_REG) !=
+ readl(iommu->reg + DMAR_IQH_REG)) &&
+ (DMAR_OPERATION_TIMEOUT > (get_cycles() - start_time)))
+ cpu_relax();
+
+ iommu->gcmd &= ~DMA_GCMD_QIE;
+
+ writel(iommu->gcmd, iommu->reg + DMAR_GCMD_REG);
+
+ IOMMU_WAIT_OP(iommu, DMAR_GSTS_REG, readl,
+ !(sts & DMA_GSTS_QIES), sts);
+end:
+ spin_unlock_irqrestore(&iommu->register_lock, flags);
+}
+