x86, dmar: routines for disabling queued invalidation and intr remapping
Impact: new interfaces (not yet used)
Routines for disabling queued invalidation and interrupt remapping.
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
diff --git a/drivers/pci/dmar.c b/drivers/pci/dmar.c
index bb4ed98..932e5e3 100644
--- a/drivers/pci/dmar.c
+++ b/drivers/pci/dmar.c
@@ -754,6 +754,42 @@
}
/*
+ * 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);
+}
+
+/*
* Enable Queued Invalidation interface. This is a must to support
* interrupt-remapping. Also used by DMA-remapping, which replaces
* register based IOTLB invalidation.