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>

3 files changed, 44 insertions, 34 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,
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,
diff --git a/arch/x86/pci/common.c b/arch/x86/pci/common.c
index 07c55ce6fdf5..323481e06ef8 100644
--- a/arch/x86/pci/common.c
+++ b/arch/x86/pci/common.c
@@ -164,9 +164,6 @@ void __devinit pcibios_fixup_bus(struct pci_bus *b)
 {
         struct pci_dev *dev;
 
-        /* root bus? */
-        if (!b->parent)
-                x86_pci_root_bus_res_quirks(b);
         pci_read_bridge_bases(b);
         list_for_each_entry(dev, &b->devices, bus_list)
                 pcibios_fixup_device_resources(dev);
@@ -433,6 +430,7 @@ void __init dmi_check_pciprobe(void)
 
 struct pci_bus * __devinit pcibios_scan_root(int busnum)
 {
+        LIST_HEAD(resources);
         struct pci_bus *bus = NULL;
         struct pci_sysdata *sd;
 
@@ -456,9 +454,12 @@ struct pci_bus * __devinit pcibios_scan_root(int busnum)
         sd->node = get_mp_bus_to_node(busnum);
 
         printk(KERN_DEBUG "PCI: Probing PCI hardware (bus %02x)\n", busnum);
-        bus = pci_scan_bus(busnum, &pci_root_ops, sd);
-        if (!bus)
+        x86_pci_root_bus_resources(busnum, &resources);
+        bus = pci_scan_root_bus(NULL, busnum, &pci_root_ops, sd, &resources);
+        if (!bus) {
+                pci_free_resource_list(&resources);
                 kfree(sd);
+        }
 
         return bus;
 }
@@ -639,6 +640,7 @@ int pci_ext_cfg_avail(struct pci_dev *dev)
 
 struct pci_bus * __devinit pci_scan_bus_on_node(int busno, struct pci_ops *ops, int node)
 {
+        LIST_HEAD(resources);
         struct pci_bus *bus = NULL;
         struct pci_sysdata *sd;
 
@@ -653,9 +655,12 @@ struct pci_bus * __devinit pci_scan_bus_on_node(int busno, struct pci_ops *ops,
                 return NULL;
         }
         sd->node = node;
-        bus = pci_scan_bus(busno, ops, sd);
-        if (!bus)
+        x86_pci_root_bus_resources(busno, &resources);
+        bus = pci_scan_root_bus(NULL, busno, ops, sd, &resources);
+        if (!bus) {
+                pci_free_resource_list(&resources);
                 kfree(sd);
+        }
 
         return bus;
 }