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, 18 insertions, 13 deletions

diff --git a/arch/x86/pci/bus_numa.c b/arch/x86/pci/bus_numa.c
index 64a122883896..fd3f65510e9d 100644
--- a/arch/x86/pci/bus_numa.c
+++ b/arch/x86/pci/bus_numa.c
@@ -7,45 +7,50 @@
 int pci_root_num;
 struct pci_root_info pci_root_info[PCI_ROOT_NR];
 
-void x86_pci_root_bus_res_quirks(struct pci_bus *b)
+void x86_pci_root_bus_resources(int bus, struct list_head *resources)
 {
 	int i;
 	int j;
 	struct pci_root_info *info;
 
-	/* don't go for it if _CRS is used already */
-	if (b->resource[0] != &ioport_resource ||
-	    b->resource[1] != &iomem_resource)
-		return;
-
 	if (!pci_root_num)
-		return;
+		goto default_resources;
 
 	for (i = 0; i < pci_root_num; i++) {
-		if (pci_root_info[i].bus_min == b->number)
+		if (pci_root_info[i].bus_min == bus)
 			break;
 	}
 
 	if (i == pci_root_num)
-		return;
+		goto default_resources;
 
-	printk(KERN_DEBUG "PCI: peer root bus %02x res updated from pci conf\n",
-			b->number);
+	printk(KERN_DEBUG "PCI: root bus %02x: hardware-probed resources\n",
+	       bus);
 
-	pci_bus_remove_resources(b);
 	info = &pci_root_info[i];
 	for (j = 0; j < info->res_num; j++) {
 		struct resource *res;
 		struct resource *root;
 
 		res = &info->res[j];
-		pci_bus_add_resource(b, res, 0);
+		pci_add_resource(resources, res);
 		if (res->flags & IORESOURCE_IO)
 			root = &ioport_resource;
 		else
 			root = &iomem_resource;
 		insert_resource(root, res);
 	}
+	return;
+
+default_resources:
+	/*
+	 * We don't have any host bridge aperture information from the
+	 * "native host bridge drivers," e.g., amd_bus or broadcom_bus,
+	 * so fall back to the defaults historically used by pci_create_bus().
+	 */
+	printk(KERN_DEBUG "PCI: root bus %02x: using default resources\n", bus);
+	pci_add_resource(resources, &ioport_resource);
+	pci_add_resource(resources, &iomem_resource);
 }
 
 void __devinit update_res(struct pci_root_info *info, resource_size_t start,