PCI: versatile: Convert PCI scan API to pci_scan_root_bus_bridge()

The introduction of pci_scan_root_bus_bridge() provides a PCI core API to
scan a PCI root bus backed by an already initialized struct pci_host_bridge
object, which simplifies the bus scan interface and makes the PCI scan root
bus interface easier to generalize as members are added to the struct
pci_host_bridge.

Convert PCI versatile host code to pci_scan_root_bus_bridge() to improve
the PCI root bus scanning interface.
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
[bhelgaas: folded in fix from Arnd Bergmann <arnd@arndb.de>:
http://lkml.kernel.org/r/20170621215323.3921382-3-arnd@arndb.de]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Rob Herring <robh@kernel.org>

drivers/pci/host/pci-versatile.c

@@ -125,8 +125,13 @@ static int versatile_pci_probe(struct platform_device *pdev)
 	u32 val;
 	void __iomem *local_pci_cfg_base;
 	struct pci_bus *bus, *child;
+	struct pci_host_bridge *bridge;
 	LIST_HEAD(pci_res);
 
+	bridge = devm_pci_alloc_host_bridge(&pdev->dev, 0);
+	if (!bridge)
+		return -ENOMEM;
+
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	versatile_pci_base = devm_ioremap_resource(&pdev->dev, res);
 	if (IS_ERR(versatile_pci_base))
@@ -199,11 +204,20 @@ static int versatile_pci_probe(struct platform_device *pdev)
 	pci_add_flags(PCI_ENABLE_PROC_DOMAINS);
 	pci_add_flags(PCI_REASSIGN_ALL_BUS | PCI_REASSIGN_ALL_RSRC);
 
-	bus = pci_scan_root_bus(&pdev->dev, 0, &pci_versatile_ops, NULL, &pci_res);
-	if (!bus)
-		return -ENOMEM;
+	list_splice_init(&pci_res, &bridge->windows);
+	bridge->dev.parent = &pdev->dev;
+	bridge->sysdata = NULL;
+	bridge->busnr = 0;
+	bridge->ops = &pci_versatile_ops;
+
+	ret = pci_scan_root_bus_bridge(bridge);
+	if (ret < 0)
+		return ret;
+
+	bus = bridge->bus;
 
 	pci_fixup_irqs(pci_common_swizzle, of_irq_parse_and_map_pci);
+
 	pci_assign_unassigned_bus_resources(bus);
 	list_for_each_entry(child, &bus->children, node)
 		pcie_bus_configure_settings(child);