x86/PCI: convert to pci_create_root_bus() and pci_scan_root_bus()

x86 has two kinds of PCI root bus scanning:

(1) ACPI-based, using _CRS resources.  This used pci_create_bus(), not
    pci_scan_bus(), because ACPI hotplug needed to split the
    pci_bus_add_devices() into a separate host bridge .start() method.

    This patch parses the _CRS resources earlier, so we can build a list of
    resources and pass it to pci_create_root_bus().

    Note that as before, we parse the _CRS even if we aren't going to use
    it so we can print it for debugging purposes.

(2) All other, which used either default resources (ioport_resource and
    iomem_resource) or information read from the hardware via amd_bus.c or
    similar.  This used pci_scan_bus().

    This patch converts x86_pci_root_bus_res_quirks() (previously called
    from pcibios_fixup_bus()) to x86_pci_root_bus_resources(), which builds
    a list of resources before we call pci_scan_root_bus().

    We also use x86_pci_root_bus_resources() if we have ACPI but are
    ignoring _CRS.

CC: Yinghai Lu <yinghai.lu@oracle.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

1 files changed, 14 insertions, 14 deletions

diff --git a/arch/x86/pci/acpi.c b/arch/x86/pci/acpi.c
index 425500b..a312e76 100644
--- a/arch/x86/pci/acpi.c
+++ b/arch/x86/pci/acpi.c
@@ -12,7 +12,7 @@ struct pci_root_info {
 	char *name;
 	unsigned int res_num;
 	struct resource *res;
-	struct pci_bus *bus;
+	struct list_head *resources;
 	int busnum;
 };
 
@@ -304,23 +304,20 @@ static void add_resources(struct pci_root_info *info)
 				 "ignoring host bridge window %pR (conflicts with %s %pR)\n",
 				 res, conflict->name, conflict);
 		else
-			pci_bus_add_resource(info->bus, res, 0);
+			pci_add_resource(info->resources, res);
 	}
 }
 
 static void
 get_current_resources(struct acpi_device *device, int busnum,
-			int domain, struct pci_bus *bus)
+		      int domain, struct list_head *resources)
 {
 	struct pci_root_info info;
 	size_t size;
 
-	if (pci_use_crs)
-		pci_bus_remove_resources(bus);
-
 	info.bridge = device;
-	info.bus = bus;
 	info.res_num = 0;
+	info.resources = resources;
 	acpi_walk_resources(device->handle, METHOD_NAME__CRS, count_resource,
 				&info);
 	if (!info.res_num)
@@ -329,7 +326,7 @@ get_current_resources(struct acpi_device *device, int busnum,
 	size = sizeof(*info.res) * info.res_num;
 	info.res = kmalloc(size, GFP_KERNEL);
 	if (!info.res)
-		goto res_alloc_fail;
+		return;
 
 	info.name = kasprintf(GFP_KERNEL, "PCI Bus %04x:%02x", domain, busnum);
 	if (!info.name)
@@ -344,8 +341,6 @@ get_current_resources(struct acpi_device *device, int busnum,
 
 name_alloc_fail:
 	kfree(info.res);
-res_alloc_fail:
-	return;
 }
 
 struct pci_bus * __devinit pci_acpi_scan_root(struct acpi_pci_root *root)
@@ -353,6 +348,7 @@ struct pci_bus * __devinit pci_acpi_scan_root(struct acpi_pci_root *root)
 	struct acpi_device *device = root->device;
 	int domain = root->segment;
 	int busnum = root->secondary.start;
+	LIST_HEAD(resources);
 	struct pci_bus *bus;
 	struct pci_sysdata *sd;
 	int node;
@@ -407,11 +403,15 @@ struct pci_bus * __devinit pci_acpi_scan_root(struct acpi_pci_root *root)
 		memcpy(bus->sysdata, sd, sizeof(*sd));
 		kfree(sd);
 	} else {
-		bus = pci_create_bus(NULL, busnum, &pci_root_ops, sd);
-		if (bus) {
-			get_current_resources(device, busnum, domain, bus);
+		get_current_resources(device, busnum, domain, &resources);
+		if (list_empty(&resources))
+			x86_pci_root_bus_resources(busnum, &resources);
+		bus = pci_create_root_bus(NULL, busnum, &pci_root_ops, sd,
+					  &resources);
+		if (bus)
 			bus->subordinate = pci_scan_child_bus(bus);
-		}
+		else
+			pci_free_resource_list(&resources);
 	}
 
 	/* After the PCI-E bus has been walked and all devices discovered,