PCI: acpiphp: Move host bridge hotplug to pci_root.c

The acpiphp driver is confusing because it contains partial support for PCI
host bridge hotplug as well as support for hotplug of PCI devices.

This patch moves the host bridge hot-add support to pci_root.c and adds
hot-remove support in pci_root.c.

How to test it: if sci_emu patch is applied, find out root bus number to
ACPI root name mapping from dmesg or /sys.  To remove root bus:

  echo "\_SB.PCIB 3" > /sys/kernel/debug/acpi/sci_notify

To add back root bus:

  echo "\_SB.PCIB 1" > /sys/kernel/debug/acpi/sci_notify

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
diff --git a/drivers/pci/hotplug/acpiphp_glue.c b/drivers/pci/hotplug/acpiphp_glue.c
index bf338d2..c4a6301 100644
--- a/drivers/pci/hotplug/acpiphp_glue.c
+++ b/drivers/pci/hotplug/acpiphp_glue.c
@@ -543,10 +543,13 @@
 	acpi_status status;
 	acpi_handle handle = bridge->handle;
 
-	status = acpi_remove_notify_handler(handle, ACPI_SYSTEM_NOTIFY,
+	if (bridge->type != BRIDGE_TYPE_HOST) {
+		status = acpi_remove_notify_handler(handle,
+					    ACPI_SYSTEM_NOTIFY,
 					    handle_hotplug_event_bridge);
-	if (ACPI_FAILURE(status))
-		err("failed to remove notify handler\n");
+		if (ACPI_FAILURE(status))
+			err("failed to remove notify handler\n");
+	}
 
 	if ((bridge->type != BRIDGE_TYPE_HOST) &&
 	    ((bridge->flags & BRIDGE_HAS_EJ0) && bridge->func)) {
@@ -630,9 +633,6 @@
 	bridge = acpiphp_handle_to_bridge(handle);
 	if (bridge)
 		cleanup_bridge(bridge);
-	else
-		acpi_remove_notify_handler(handle, ACPI_SYSTEM_NOTIFY,
-					   handle_hotplug_event_bridge);
 }
 
 static int power_on_slot(struct acpiphp_slot *slot)
@@ -1123,18 +1123,12 @@
 }
 
 /* Program resources in newly inserted bridge */
-static int acpiphp_configure_bridge (acpi_handle handle)
+static int acpiphp_configure_p2p_bridge(acpi_handle handle)
 {
-	struct pci_bus *bus;
+	struct pci_dev *pdev = acpi_get_pci_dev(handle);
+	struct pci_bus *bus = pdev->subordinate;
 
-	if (acpi_is_root_bridge(handle)) {
-		struct acpi_pci_root *root = acpi_pci_find_root(handle);
-		bus = root->bus;
-	} else {
-		struct pci_dev *pdev = acpi_get_pci_dev(handle);
-		bus = pdev->subordinate;
-		pci_dev_put(pdev);
-	}
+	pci_dev_put(pdev);
 
 	pci_bus_size_bridges(bus);
 	pci_bus_assign_resources(bus);
@@ -1144,7 +1138,7 @@
 	return 0;
 }
 
-static void handle_bridge_insertion(acpi_handle handle, u32 type)
+static void handle_p2p_bridge_insertion(acpi_handle handle, u32 type)
 {
 	struct acpi_device *device;
 
@@ -1162,8 +1156,8 @@
 		err("ACPI device object missing\n");
 		return;
 	}
-	if (!acpiphp_configure_bridge(handle))
-		add_bridge(handle);
+	if (!acpiphp_configure_p2p_bridge(handle))
+		add_p2p_bridge(handle);
 	else
 		err("cannot configure and start bridge\n");
 
@@ -1221,7 +1215,7 @@
 
 	if (acpi_bus_get_device(handle, &device)) {
 		/* This bridge must have just been physically inserted */
-		handle_bridge_insertion(handle, type);
+		handle_p2p_bridge_insertion(handle, type);
 		goto out;
 	}
 
@@ -1396,21 +1390,6 @@
 	alloc_acpi_hp_work(handle, type, context, _handle_hotplug_event_func);
 }
 
-static acpi_status
-find_root_bridges(acpi_handle handle, u32 lvl, void *context, void **rv)
-{
-	int *count = (int *)context;
-
-	if (!acpi_is_root_bridge(handle))
-		return AE_OK;
-
-	(*count)++;
-	acpi_install_notify_handler(handle, ACPI_SYSTEM_NOTIFY,
-				    handle_hotplug_event_bridge, NULL);
-
-	return AE_OK ;
-}
-
 static struct acpi_pci_driver acpi_pci_hp_driver = {
 	.add =		add_bridge,
 	.remove =	remove_bridge,
@@ -1421,15 +1400,7 @@
  */
 int __init acpiphp_glue_init(void)
 {
-	int num = 0;
-
-	acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
-			ACPI_UINT32_MAX, find_root_bridges, NULL, &num, NULL);
-
-	if (num <= 0)
-		return -1;
-	else
-		acpi_pci_register_driver(&acpi_pci_hp_driver);
+	acpi_pci_register_driver(&acpi_pci_hp_driver);
 
 	return 0;
 }