diff --git a/Documentation/devicetree/bindings/pci/pci.txt b/Documentation/devicetree/bindings/pci/pci.txt
index 41aeed38926d19e84b67f3194994ded9c584106c..f8fbe9af7b2f276350426b299c6030adb9464640 100644
--- a/Documentation/devicetree/bindings/pci/pci.txt
+++ b/Documentation/devicetree/bindings/pci/pci.txt
@@ -7,3 +7,14 @@ And for the interrupt mapping part:
 
 Open Firmware Recommended Practice: Interrupt Mapping
 http://www.openfirmware.org/1275/practice/imap/imap0_9d.pdf
+
+Additionally to the properties specified in the above standards a host bridge
+driver implementation may support the following properties:
+
+- linux,pci-domain:
+   If present this property assigns a fixed PCI domain number to a host bridge,
+   otherwise an unstable (across boots) unique number will be assigned.
+   It is required to either not set this property at all or set it for all
+   host bridges in the system, otherwise potentially conflicting domain numbers
+   may be assigned to root buses behind different host bridges.  The domain
+   number for each host bridge in the system must be unique.
diff --git a/drivers/pci/access.c b/drivers/pci/access.c
index d292d7cb3417062643379805a969f5d29718de2f..49dd766852ba58f5ebad21199e38f1e2a912b498 100644
--- a/drivers/pci/access.c
+++ b/drivers/pci/access.c
@@ -444,7 +444,7 @@ static inline int pcie_cap_version(const struct pci_dev *dev)
 	return pcie_caps_reg(dev) & PCI_EXP_FLAGS_VERS;
 }
 
-static inline bool pcie_cap_has_lnkctl(const struct pci_dev *dev)
+bool pcie_cap_has_lnkctl(const struct pci_dev *dev)
 {
 	int type = pci_pcie_type(dev);
 
diff --git a/drivers/pci/host/pci-xgene.c b/drivers/pci/host/pci-xgene.c
index 9ecabfa8c6343a83afba9d33b101bc4161b6bd3f..2988fe136c1e3ede0240e90db80d6e4e013e6e8a 100644
--- a/drivers/pci/host/pci-xgene.c
+++ b/drivers/pci/host/pci-xgene.c
@@ -631,10 +631,15 @@ static int xgene_pcie_probe_bridge(struct platform_device *pdev)
 	if (ret)
 		return ret;
 
-	bus = pci_scan_root_bus(&pdev->dev, 0, &xgene_pcie_ops, port, &res);
+	bus = pci_create_root_bus(&pdev->dev, 0,
+					&xgene_pcie_ops, port, &res);
 	if (!bus)
 		return -ENOMEM;
 
+	pci_scan_child_bus(bus);
+	pci_assign_unassigned_bus_resources(bus);
+	pci_bus_add_devices(bus);
+
 	platform_set_drvdata(pdev, port);
 	return 0;
 }
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 0601890db22de96131af2d67fd872651ab608133..4a3902d8e6fec7984bb483b55aee4115101cc1f4 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -6,6 +6,8 @@
 
 extern const unsigned char pcie_link_speed[];
 
+bool pcie_cap_has_lnkctl(const struct pci_dev *dev);
+
 /* Functions internal to the PCI core code */
 
 int pci_create_sysfs_dev_files(struct pci_dev *pdev);
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 5ed99309c75800938b666c5c523d7ea3ca07d51f..c8ca98c2b480a41d57676ef21e97cd6612134110 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -407,15 +407,16 @@ static void pci_read_bridge_mmio_pref(struct pci_bus *child)
 {
 	struct pci_dev *dev = child->self;
 	u16 mem_base_lo, mem_limit_lo;
-	unsigned long base, limit;
+	u64 base64, limit64;
+	dma_addr_t base, limit;
 	struct pci_bus_region region;
 	struct resource *res;
 
 	res = child->resource[2];
 	pci_read_config_word(dev, PCI_PREF_MEMORY_BASE, &mem_base_lo);
 	pci_read_config_word(dev, PCI_PREF_MEMORY_LIMIT, &mem_limit_lo);
-	base = ((unsigned long) mem_base_lo & PCI_PREF_RANGE_MASK) << 16;
-	limit = ((unsigned long) mem_limit_lo & PCI_PREF_RANGE_MASK) << 16;
+	base64 = (mem_base_lo & PCI_PREF_RANGE_MASK) << 16;
+	limit64 = (mem_limit_lo & PCI_PREF_RANGE_MASK) << 16;
 
 	if ((mem_base_lo & PCI_PREF_RANGE_TYPE_MASK) == PCI_PREF_RANGE_TYPE_64) {
 		u32 mem_base_hi, mem_limit_hi;
@@ -429,17 +430,20 @@ static void pci_read_bridge_mmio_pref(struct pci_bus *child)
 		 * this, just assume they are not being used.
 		 */
 		if (mem_base_hi <= mem_limit_hi) {
-#if BITS_PER_LONG == 64
-			base |= ((unsigned long) mem_base_hi) << 32;
-			limit |= ((unsigned long) mem_limit_hi) << 32;
-#else
-			if (mem_base_hi || mem_limit_hi) {
-				dev_err(&dev->dev, "can't handle 64-bit address space for bridge\n");
-				return;
-			}
-#endif
+			base64 |= (u64) mem_base_hi << 32;
+			limit64 |= (u64) mem_limit_hi << 32;
 		}
 	}
+
+	base = (dma_addr_t) base64;
+	limit = (dma_addr_t) limit64;
+
+	if (base != base64) {
+		dev_err(&dev->dev, "can't handle bridge window above 4GB (bus address %#010llx)\n",
+			(unsigned long long) base64);
+		return;
+	}
+
 	if (base <= limit) {
 		res->flags = (mem_base_lo & PCI_PREF_RANGE_TYPE_MASK) |
 					 IORESOURCE_MEM | IORESOURCE_PREFETCH;
@@ -1323,7 +1327,7 @@ static void program_hpp_type2(struct pci_dev *dev, struct hpp_type2 *hpp)
 			~hpp->pci_exp_devctl_and, hpp->pci_exp_devctl_or);
 
 	/* Initialize Link Control Register */
-	if (dev->subordinate)
+	if (pcie_cap_has_lnkctl(dev))
 		pcie_capability_clear_and_set_word(dev, PCI_EXP_LNKCTL,
 			~hpp->pci_exp_lnkctl_and, hpp->pci_exp_lnkctl_or);