PCI: pciehp: second try to get big range for pcie devices

Handle the case where the slot bridge that doesn't get a pre-allocated
resource big enough to handle its child resources..  For example pcie
devices need 256M, but the bridge only gets 2M preallocated.
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>

drivers/pci/setup-bus.c

@@ -964,12 +964,61 @@ pci_assign_unassigned_resources(void)
 void pci_assign_unassigned_bridge_resources(struct pci_dev *bridge)
 {
 	struct pci_bus *parent = bridge->subordinate;
+	int tried_times = 0;
+	struct resource_list_x head, *list;
 	int retval;
+	unsigned long type_mask = IORESOURCE_IO | IORESOURCE_MEM |
+				  IORESOURCE_PREFETCH;
+
+	head.next = NULL;
 
+again:
 	pci_bus_size_bridges(parent);
-	__pci_bridge_assign_resources(bridge, NULL);
+	__pci_bridge_assign_resources(bridge, &head);
 	retval = pci_reenable_device(bridge);
 	pci_set_master(bridge);
 	pci_enable_bridges(parent);
+
+	tried_times++;
+
+	if (!head.next)
+		return;
+
+	if (tried_times >= 2) {
+		/* still fail, don't need to try more */
+		free_failed_list(&head);
+		return;
+	}
+
+	printk(KERN_DEBUG "PCI: No. %d try to assign unassigned res\n",
+			 tried_times + 1);
+
+	/*
+	 * Try to release leaf bridge's resources that doesn't fit resource of
+	 * child device under that bridge
+	 */
+	for (list = head.next; list;) {
+		struct pci_bus *bus = list->dev->bus;
+		unsigned long flags = list->flags;
+
+		pci_bus_release_bridge_resources(bus, flags & type_mask,
+						 whole_subtree);
+		list = list->next;
+	}
+	/* restore size and flags */
+	for (list = head.next; list;) {
+		struct resource *res = list->res;
+
+		res->start = list->start;
+		res->end = list->end;
+		res->flags = list->flags;
+		if (list->dev->subordinate)
+			res->flags = 0;
+
+		list = list->next;
+	}
+	free_failed_list(&head);
+
+	goto again;
 }
 EXPORT_SYMBOL_GPL(pci_assign_unassigned_bridge_resources);