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>

1 files changed, 36 insertions, 0 deletions

diff --git a/drivers/pci/dmar.c b/drivers/pci/dmar.c
index bb4ed985f9c7..932e5e3930fc 100644
--- a/drivers/pci/dmar.c
+++ b/drivers/pci/dmar.c
@@ -754,6 +754,42 @@ int qi_flush_iotlb(struct intel_iommu *iommu, u16 did, u64 addr,
 }
 
 /*
+ * 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.