1 files changed, 32 insertions, 4 deletions

diff --git a/arch/powerpc/kernel/pci-common.c b/arch/powerpc/kernel/pci-common.c
index 2aa04f29e1de..7f94f760dd0c 100644
--- a/arch/powerpc/kernel/pci-common.c
+++ b/arch/powerpc/kernel/pci-common.c
@@ -99,6 +99,26 @@ void pcibios_free_controller(struct pci_controller *phb)
 		kfree(phb);
 }
 
+/*
+ * The function is used to return the minimal alignment
+ * for memory or I/O windows of the associated P2P bridge.
+ * By default, 4KiB alignment for I/O windows and 1MiB for
+ * memory windows.
+ */
+resource_size_t pcibios_window_alignment(struct pci_bus *bus,
+					 unsigned long type)
+{
+	if (ppc_md.pcibios_window_alignment)
+		return ppc_md.pcibios_window_alignment(bus, type);
+
+	/*
+	 * PCI core will figure out the default
+	 * alignment: 4KiB for I/O and 1MiB for
+	 * memory window.
+	 */
+	return 1;
+}
+
 static resource_size_t pcibios_io_size(const struct pci_controller *hose)
 {
 #ifdef CONFIG_PPC64
@@ -960,13 +980,14 @@ static void __devinit pcibios_fixup_bridge(struct pci_bus *bus)
 		if (i >= 3 && bus->self->transparent)
 			continue;
 
-		/* If we are going to re-assign everything, mark the resource
-		 * as unset and move it down to 0
+		/* If we're going to reassign everything, we can
+		 * shrink the P2P resource to have size as being
+		 * of 0 in order to save space.
 		 */
 		if (pci_has_flag(PCI_REASSIGN_ALL_RSRC)) {
 			res->flags |= IORESOURCE_UNSET;
-			res->end -= res->start;
 			res->start = 0;
+			res->end = -1;
 			continue;
 		}
 
@@ -1228,7 +1249,14 @@ void pcibios_allocate_bus_resources(struct pci_bus *bus)
 		pr_warning("PCI: Cannot allocate resource region "
 			   "%d of PCI bridge %d, will remap\n", i, bus->number);
 	clear_resource:
-		res->start = res->end = 0;
+		/* The resource might be figured out when doing
+		 * reassignment based on the resources required
+		 * by the downstream PCI devices. Here we set
+		 * the size of the resource to be 0 in order to
+		 * save more space.
+		 */
+		res->start = 0;
+		res->end = -1;
 		res->flags = 0;
 	}