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path: root/drivers/pci/bus.c
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Diffstat (limited to 'drivers/pci/bus.c')
-rw-r--r--drivers/pci/bus.c70
1 files changed, 21 insertions, 49 deletions
diff --git a/drivers/pci/bus.c b/drivers/pci/bus.c
index 003170ea2e39..5624db8c9ad0 100644
--- a/drivers/pci/bus.c
+++ b/drivers/pci/bus.c
@@ -64,57 +64,17 @@ 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 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.
+ * Find the highest-address bus resource below the cursor "res". If the
+ * cursor is NULL, return the highest resource.
*/
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;
@@ -122,14 +82,26 @@ static struct resource *pci_bus_find_resource_prev(struct pci_bus *bus,
if ((r->flags & IORESOURCE_TYPE_BITS) != type)
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 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;
}
+
+ 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;