Merge branch 'pci/resource'

- Coalesce host bridge contiguous apertures to allow P2P bridge windows
  that span several contiguous host bridge apertures (Kai-Heng Feng)

* pci/resource:
  PCI: Coalesce host bridge contiguous apertures

1 files changed, 27 insertions, 4 deletions

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 240e4cf8c83e..78ca4cbebbb7 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -883,11 +883,11 @@ static void pci_set_bus_msi_domain(struct pci_bus *bus)
 static int pci_register_host_bridge(struct pci_host_bridge *bridge)
 {
 	struct device *parent = bridge->dev.parent;
-	struct resource_entry *window, *n;
+	struct resource_entry *window, *next, *n;
 	struct pci_bus *bus, *b;
-	resource_size_t offset;
+	resource_size_t offset, next_offset;
 	LIST_HEAD(resources);
-	struct resource *res;
+	struct resource *res, *next_res;
 	char addr[64], *fmt;
 	const char *name;
 	int err;
@@ -970,11 +970,34 @@ static int pci_register_host_bridge(struct pci_host_bridge *bridge)
 	if (nr_node_ids > 1 && pcibus_to_node(bus) == NUMA_NO_NODE)
 		dev_warn(&bus->dev, "Unknown NUMA node; performance will be reduced\n");
 
+	/* Coalesce contiguous windows */
+	resource_list_for_each_entry_safe(window, n, &resources) {
+		if (list_is_last(&window->node, &resources))
+			break;
+
+		next = list_next_entry(window, node);
+		offset = window->offset;
+		res = window->res;
+		next_offset = next->offset;
+		next_res = next->res;
+
+		if (res->flags != next_res->flags || offset != next_offset)
+			continue;
+
+		if (res->end + 1 == next_res->start) {
+			next_res->start = res->start;
+			res->flags = res->start = res->end = 0;
+		}
+	}
+
 	/* Add initial resources to the bus */
 	resource_list_for_each_entry_safe(window, n, &resources) {
-		list_move_tail(&window->node, &bridge->windows);
 		offset = window->offset;
 		res = window->res;
+		if (!res->end)
+			continue;
+
+		list_move_tail(&window->node, &bridge->windows);
 
 		if (res->flags & IORESOURCE_BUS)
 			pci_bus_insert_busn_res(bus, bus->number, res->end);