1 files changed, 117 insertions, 8 deletions

diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
index ebf51ad1b714..7a65db400253 100644
--- a/drivers/pci/setup-bus.c
+++ b/drivers/pci/setup-bus.c
@@ -991,30 +991,139 @@ static void pci_bus_dump_resources(struct pci_bus *bus)
         }
 }
 
+static int __init pci_bus_get_depth(struct pci_bus *bus)
+{
+        int depth = 0;
+        struct pci_dev *dev;
+
+        list_for_each_entry(dev, &bus->devices, bus_list) {
+                int ret;
+                struct pci_bus *b = dev->subordinate;
+                if (!b)
+                        continue;
+
+                ret = pci_bus_get_depth(b);
+                if (ret + 1 > depth)
+                        depth = ret + 1;
+        }
+
+        return depth;
+}
+static int __init pci_get_max_depth(void)
+{
+        int depth = 0;
+        struct pci_bus *bus;
+
+        list_for_each_entry(bus, &pci_root_buses, node) {
+                int ret;
+
+                ret = pci_bus_get_depth(bus);
+                if (ret > depth)
+                        depth = ret;
+        }
+
+        return depth;
+}
+
+/*
+ * first try will not touch pci bridge res
+ * second  and later try will clear small leaf bridge res
+ * will stop till to the max  deepth if can not find good one
+ */
 void __init
 pci_assign_unassigned_resources(void)
 {
         struct pci_bus *bus;
         struct resource_list_x add_list; /* list of resources that
                                         want additional resources */
+        int tried_times = 0;
+        enum release_type rel_type = leaf_only;
+        struct resource_list_x head, *list;
+        unsigned long type_mask = IORESOURCE_IO | IORESOURCE_MEM |
+                                  IORESOURCE_PREFETCH;
+        unsigned long failed_type;
+        int max_depth = pci_get_max_depth();
+        int pci_try_num;
+
+
+        head.next = NULL;
         add_list.next = NULL;
+
+        pci_try_num = max_depth + 1;
+        printk(KERN_DEBUG "PCI: max bus depth: %d pci_try_num: %d\n",
+                 max_depth, pci_try_num);
+
+again:
         /* Depth first, calculate sizes and alignments of all
            subordinate buses. */
-        list_for_each_entry(bus, &pci_root_buses, node) {
+        list_for_each_entry(bus, &pci_root_buses, node)
                 __pci_bus_size_bridges(bus, &add_list);
-        }
 
         /* Depth last, allocate resources and update the hardware. */
-        list_for_each_entry(bus, &pci_root_buses, node) {
-                __pci_bus_assign_resources(bus, &add_list, NULL);
-                pci_enable_bridges(bus);
-        }
+        list_for_each_entry(bus, &pci_root_buses, node)
+                __pci_bus_assign_resources(bus, &add_list, &head);
         BUG_ON(add_list.next);
+        tried_times++;
+
+        /* any device complain? */
+        if (!head.next)
+                goto enable_and_dump;
+        failed_type = 0;
+        for (list = head.next; list;) {
+                failed_type |= list->flags;
+                list = list->next;
+        }
+        /*
+         * io port are tight, don't try extra
+         * or if reach the limit, don't want to try more
+         */
+        failed_type &= type_mask;
+        if ((failed_type == IORESOURCE_IO) || (tried_times >= pci_try_num)) {
+                free_list(resource_list_x, &head);
+                goto enable_and_dump;
+        }
+
+        printk(KERN_DEBUG "PCI: No. %d try to assign unassigned res\n",
+                         tried_times + 1);
+
+        /* third times and later will not check if it is leaf */
+        if ((tried_times + 1) > 2)
+                rel_type = whole_subtree;
+
+        /*
+         * Try to release leaf bridge's resources that doesn't fit resource of
+         * child device under that bridge
+         */
+        for (list = head.next; list;) {
+                bus = list->dev->bus;
+                pci_bus_release_bridge_resources(bus, list->flags & type_mask,
+                                                  rel_type);
+                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_list(resource_list_x, &head);
+
+        goto again;
+
+enable_and_dump:
+        /* Depth last, update the hardware. */
+        list_for_each_entry(bus, &pci_root_buses, node)
+                pci_enable_bridges(bus);
 
         /* dump the resource on buses */
-        list_for_each_entry(bus, &pci_root_buses, node) {
+        list_for_each_entry(bus, &pci_root_buses, node)
                 pci_bus_dump_resources(bus);
-        }
 }
 
 void pci_assign_unassigned_bridge_resources(struct pci_dev *bridge)