diff --git a/drivers/iommu/amd_iommu_init.c b/drivers/iommu/amd_iommu_init.c
index c567903..542024b 100644
--- a/drivers/iommu/amd_iommu_init.c
+++ b/drivers/iommu/amd_iommu_init.c
@@ -1029,6 +1029,9 @@
 	if (!iommu->dev)
 		return 1;
 
+	iommu->root_pdev = pci_get_bus_and_slot(iommu->dev->bus->number,
+						PCI_DEVFN(0, 0));
+
 	iommu->cap_ptr = h->cap_ptr;
 	iommu->pci_seg = h->pci_seg;
 	iommu->mmio_phys = h->mmio_phys;
@@ -1323,20 +1326,16 @@
 {
 	int i, j;
 	u32 ioc_feature_control;
-	struct pci_dev *pdev = NULL;
+	struct pci_dev *pdev = iommu->root_pdev;
 
 	/* RD890 BIOSes may not have completely reconfigured the iommu */
-	if (!is_rd890_iommu(iommu->dev))
+	if (!is_rd890_iommu(iommu->dev) || !pdev)
 		return;
 
 	/*
 	 * First, we need to ensure that the iommu is enabled. This is
 	 * controlled by a register in the northbridge
 	 */
-	pdev = pci_get_bus_and_slot(iommu->dev->bus->number, PCI_DEVFN(0, 0));
-
-	if (!pdev)
-		return;
 
 	/* Select Northbridge indirect register 0x75 and enable writing */
 	pci_write_config_dword(pdev, 0x60, 0x75 | (1 << 7));
@@ -1346,8 +1345,6 @@
 	if (!(ioc_feature_control & 0x1))
 		pci_write_config_dword(pdev, 0x64, ioc_feature_control | 1);
 
-	pci_dev_put(pdev);
-
 	/* Restore the iommu BAR */
 	pci_write_config_dword(iommu->dev, iommu->cap_ptr + 4,
 			       iommu->stored_addr_lo);
diff --git a/drivers/iommu/amd_iommu_types.h b/drivers/iommu/amd_iommu_types.h
index 2452f3b..2435555 100644
--- a/drivers/iommu/amd_iommu_types.h
+++ b/drivers/iommu/amd_iommu_types.h
@@ -481,6 +481,9 @@
 	/* Pointer to PCI device of this IOMMU */
 	struct pci_dev *dev;
 
+	/* Cache pdev to root device for resume quirks */
+	struct pci_dev *root_pdev;
+
 	/* physical address of MMIO space */
 	u64 mmio_phys;
 	/* virtual address of MMIO space */