ACPI / PM: Do not refcount power resources that can't be turned on

[karo-tx-linux.git] / drivers / pci / bus.c

diff --git a/drivers/pci/bus.c b/drivers/pci/bus.c
index 5624db8c9ad0c511880ca16daf99f4dfb26c3769..003170ea2e394193bdcb7af4033a98bca9d46127 100644 (file)
--- a/drivers/pci/bus.c
+++ b/drivers/pci/bus.c
@@ -64,17 +64,57 @@ void pci_bus_remove_resources(struct pci_bus *bus)
        }
 }
 
+static bool pci_bus_resource_better(struct resource *res1, bool pos1,
+                                   struct resource *res2, bool pos2)
+{
+       /* If exactly one is positive decode, always prefer that one */
+       if (pos1 != pos2)
+               return pos1 ? true : false;
+
+       /* Prefer the one that contains the highest address */
+       if (res1->end != res2->end)
+               return (res1->end > res2->end) ? true : false;
+
+       /* Otherwise, prefer the one with highest "center of gravity" */
+       if (res1->start != res2->start)
+               return (res1->start > res2->start) ? true : false;
+
+       /* Otherwise, choose one arbitrarily (but consistently) */
+       return (res1 > res2) ? true : false;
+}
+
+static bool pci_bus_resource_positive(struct pci_bus *bus, struct resource *res)
+{
+       struct pci_bus_resource *bus_res;
+
+       /*
+        * This relies on the fact that pci_bus.resource[] refers to P2P or
+        * CardBus bridge base/limit registers, which are always positively
+        * decoded.  The pci_bus.resources list contains host bridge or
+        * subtractively decoded resources.
+        */
+       list_for_each_entry(bus_res, &bus->resources, list) {
+               if (bus_res->res == res)
+                       return (bus_res->flags & PCI_SUBTRACTIVE_DECODE) ?
+                               false : true;
+       }
+       return true;
+}
+
 /*
- * Find the highest-address bus resource below the cursor "res".  If the
- * cursor is NULL, return the highest resource.
+ * Find the next-best bus resource after the cursor "res".  If the cursor is
+ * NULL, return the best resource.  "Best" means that we prefer positive
+ * decode regions over subtractive decode, then those at higher addresses.
  */
 static struct resource *pci_bus_find_resource_prev(struct pci_bus *bus,
                                                   unsigned int type,
                                                   struct resource *res)
 {
+       bool res_pos, r_pos, prev_pos = false;
        struct resource *r, *prev = NULL;
        int i;
 
+       res_pos = pci_bus_resource_positive(bus, res);
        pci_bus_for_each_resource(bus, r, i) {
                if (!r)
                        continue;
@@ -82,26 +122,14 @@ static struct resource *pci_bus_find_resource_prev(struct pci_bus *bus,
                if ((r->flags & IORESOURCE_TYPE_BITS) != type)
                        continue;
 
-               /* If this resource is at or past the cursor, skip it */
-               if (res) {
-                       if (r == res)
-                               continue;
-                       if (r->end > res->end)
-                               continue;
-                       if (r->end == res->end && r->start > res->start)
-                               continue;
+               r_pos = pci_bus_resource_positive(bus, r);
+               if (!res || pci_bus_resource_better(res, res_pos, r, r_pos)) {
+                       if (!prev || pci_bus_resource_better(r, r_pos,
+                                                            prev, prev_pos)) {
+                               prev = r;
+                               prev_pos = r_pos;
+                       }
                }
-
-               if (!prev)
-                       prev = r;
-
-               /*
-                * A small resource is higher than a large one that ends at
-                * the same address.
-                */
-               if (r->end > prev->end ||
-                   (r->end == prev->end && r->start > prev->start))
-                       prev = r;
        }
 
        return prev;