[PATCH] acpi bridge hotadd: ACPI based root bridge hot-add

When you hot-plug a (root) bridge hierarchy, it may have p2p bridges and
devices attached to it that have not been configured by firmware.  In this
case, we need to configure the devices before starting them.  This patch
separates device start from device scan so that we can introduce the
configuration step in the middle.

I kept the existing semantics for pci_scan_bus() since there are a huge number
of callers to that function.

Also, I have no way of testing the changes I made to the parisc files, so this
needs review by those folks.  Sorry for the massive cross-post, this touches
files in many different places.

Signed-off-by: Rajesh Shah <rajesh.shah@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

2 files changed, 38 insertions, 2 deletions

diff --git a/drivers/acpi/pci_bind.c b/drivers/acpi/pci_bind.c
index 5d19b39e9e2b..7753df1f9fb8 100644
--- a/drivers/acpi/pci_bind.c
+++ b/drivers/acpi/pci_bind.c
@@ -129,6 +129,8 @@ acpi_pci_bind (
         char                    *pathname = NULL;
         struct acpi_buffer      buffer = {0, NULL};
         acpi_handle             handle = NULL;
+        struct pci_dev          *dev;
+        struct pci_bus          *bus;
 
         ACPI_FUNCTION_TRACE("acpi_pci_bind");
 
@@ -193,8 +195,20 @@ acpi_pci_bind (
          * Locate matching device in PCI namespace.  If it doesn't exist
          * this typically means that the device isn't currently inserted
          * (e.g. docking station, port replicator, etc.).
+         * We cannot simply search the global pci device list, since
+         * PCI devices are added to the global pci list when the root
+         * bridge start ops are run, which may not have happened yet.
          */
-        data->dev = pci_find_slot(data->id.bus, PCI_DEVFN(data->id.device, data->id.function));
+        bus = pci_find_bus(data->id.segment, data->id.bus);
+        if (bus) {
+                list_for_each_entry(dev, &bus->devices, bus_list) {
+                        if (dev->devfn == PCI_DEVFN(data->id.device,
+                                                data->id.function)) {
+                                data->dev = dev;
+                                break;
+                        }
+                }
+        }
         if (!data->dev) {
                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, 
                         "Device %02x:%02x:%02x.%02x not present in PCI namespace\n",
diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
index 7e6b8e3b2ed4..5d2f77fcd50c 100644
--- a/drivers/acpi/pci_root.c
+++ b/drivers/acpi/pci_root.c
@@ -46,6 +46,7 @@ ACPI_MODULE_NAME		("pci_root")
 
 static int acpi_pci_root_add (struct acpi_device *device);
 static int acpi_pci_root_remove (struct acpi_device *device, int type);
+static int acpi_pci_root_start (struct acpi_device *device);
 
 static struct acpi_driver acpi_pci_root_driver = {
         .name =         ACPI_PCI_ROOT_DRIVER_NAME,
@@ -54,6 +55,7 @@ static struct acpi_driver acpi_pci_root_driver = {
         .ops =          {
                                 .add =    acpi_pci_root_add,
                                 .remove = acpi_pci_root_remove,
+                                .start =  acpi_pci_root_start,
                         },
 };
 
@@ -169,6 +171,7 @@ acpi_pci_root_add (
         if (!root)
                 return_VALUE(-ENOMEM);
         memset(root, 0, sizeof(struct acpi_pci_root));
+        INIT_LIST_HEAD(&root->node);
 
         root->handle = device->handle;
         strcpy(acpi_device_name(device), ACPI_PCI_ROOT_DEVICE_NAME);
@@ -298,12 +301,31 @@ acpi_pci_root_add (
                         root->id.bus);
 
 end:
-        if (result)
+        if (result) {
+                if (!list_empty(&root->node))
+                        list_del(&root->node);
                 kfree(root);
+        }
 
         return_VALUE(result);
 }
 
+static int
+acpi_pci_root_start (
+        struct acpi_device      *device)
+{
+        struct acpi_pci_root    *root;
+
+        ACPI_FUNCTION_TRACE("acpi_pci_root_start");
+
+        list_for_each_entry(root, &acpi_pci_roots, node) {
+                if (root->handle == device->handle) {
+                        pci_bus_add_devices(root->bus);
+                        return_VALUE(0);
+                }
+        }
+        return_VALUE(-ENODEV);
+}
 
 static int
 acpi_pci_root_remove (