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 425500bb24e6..a312e76063a7 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,