diff --git a/arch/x86/include/asm/amd_iommu_proto.h b/arch/x86/include/asm/amd_iommu_proto.h
index d2544f1..cb03037 100644
--- a/arch/x86/include/asm/amd_iommu_proto.h
+++ b/arch/x86/include/asm/amd_iommu_proto.h
@@ -38,4 +38,10 @@
 
 #endif /* !CONFIG_AMD_IOMMU_STATS */
 
+static inline bool is_rd890_iommu(struct pci_dev *pdev)
+{
+	return (pdev->vendor == PCI_VENDOR_ID_ATI) &&
+	       (pdev->device == PCI_DEVICE_ID_RD890_IOMMU);
+}
+
 #endif /* _ASM_X86_AMD_IOMMU_PROTO_H  */
diff --git a/arch/x86/include/asm/amd_iommu_types.h b/arch/x86/include/asm/amd_iommu_types.h
index ef2d5cd..0861618 100644
--- a/arch/x86/include/asm/amd_iommu_types.h
+++ b/arch/x86/include/asm/amd_iommu_types.h
@@ -414,6 +414,15 @@
 
 	/* default dma_ops domain for that IOMMU */
 	struct dma_ops_domain *default_dom;
+
+	/*
+	 * This array is required to work around a potential BIOS bug.
+	 * The BIOS may miss to restore parts of the PCI configuration
+	 * space when the system resumes from S3. The result is that the
+	 * IOMMU does not execute commands anymore which leads to system
+	 * failure.
+	 */
+	u32 cache_cfg[4];
 };
 
 /*