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>

3 files changed, 128 insertions, 0 deletions

diff --git a/drivers/acpi/internal.h b/drivers/acpi/internal.h
index e050254ae143..0f24148a2b2a 100644
--- a/drivers/acpi/internal.h
+++ b/drivers/acpi/internal.h
@@ -68,6 +68,7 @@ struct acpi_ec {
 extern struct acpi_ec *first_ec;
 
 int acpi_pci_root_init(void);
+void acpi_pci_root_hp_init(void);
 int acpi_ec_init(void);
 int acpi_ec_ecdt_probe(void);
 int acpi_boot_ec_enable(void);
diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
index 471b2dcb1c67..1389811aa21b 100644
--- a/drivers/acpi/pci_root.c
+++ b/drivers/acpi/pci_root.c
@@ -673,3 +673,127 @@ int __init acpi_pci_root_init(void)
 
 	return 0;
 }
+/* Support root bridge hotplug */
+
+static void handle_root_bridge_insertion(acpi_handle handle)
+{
+	struct acpi_device *device;
+
+	if (!acpi_bus_get_device(handle, &device)) {
+		printk(KERN_DEBUG "acpi device exists...\n");
+		return;
+	}
+
+	if (acpi_bus_scan(handle))
+		printk(KERN_ERR "cannot add bridge to acpi list\n");
+}
+
+static void handle_root_bridge_removal(struct acpi_device *device)
+{
+	struct acpi_eject_event *ej_event;
+
+	ej_event = kmalloc(sizeof(*ej_event), GFP_KERNEL);
+	if (!ej_event) {
+		/* Inform firmware the hot-remove operation has error */
+		(void) acpi_evaluate_hotplug_ost(device->handle,
+					ACPI_NOTIFY_EJECT_REQUEST,
+					ACPI_OST_SC_NON_SPECIFIC_FAILURE,
+					NULL);
+		return;
+	}
+
+	ej_event->device = device;
+	ej_event->event = ACPI_NOTIFY_EJECT_REQUEST;
+
+	acpi_bus_hot_remove_device(ej_event);
+}
+
+static void _handle_hotplug_event_root(struct work_struct *work)
+{
+	struct acpi_pci_root *root;
+	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER };
+	struct acpi_hp_work *hp_work;
+	acpi_handle handle;
+	u32 type;
+
+	hp_work = container_of(work, struct acpi_hp_work, work);
+	handle = hp_work->handle;
+	type = hp_work->type;
+
+	root = acpi_pci_find_root(handle);
+
+	acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
+
+	switch (type) {
+	case ACPI_NOTIFY_BUS_CHECK:
+		/* bus enumerate */
+		printk(KERN_DEBUG "%s: Bus check notify on %s\n", __func__,
+				 (char *)buffer.pointer);
+		if (!root)
+			handle_root_bridge_insertion(handle);
+
+		break;
+
+	case ACPI_NOTIFY_DEVICE_CHECK:
+		/* device check */
+		printk(KERN_DEBUG "%s: Device check notify on %s\n", __func__,
+				 (char *)buffer.pointer);
+		if (!root)
+			handle_root_bridge_insertion(handle);
+		break;
+
+	case ACPI_NOTIFY_EJECT_REQUEST:
+		/* request device eject */
+		printk(KERN_DEBUG "%s: Device eject notify on %s\n", __func__,
+				 (char *)buffer.pointer);
+		if (root)
+			handle_root_bridge_removal(root->device);
+		break;
+	default:
+		printk(KERN_WARNING "notify_handler: unknown event type 0x%x for %s\n",
+				 type, (char *)buffer.pointer);
+		break;
+	}
+
+	kfree(hp_work); /* allocated in handle_hotplug_event_bridge */
+	kfree(buffer.pointer);
+}
+
+static void handle_hotplug_event_root(acpi_handle handle, u32 type,
+					void *context)
+{
+	alloc_acpi_hp_work(handle, type, context,
+				_handle_hotplug_event_root);
+}
+
+static acpi_status __init
+find_root_bridges(acpi_handle handle, u32 lvl, void *context, void **rv)
+{
+	char objname[64];
+	struct acpi_buffer buffer = { .length = sizeof(objname),
+				      .pointer = objname };
+	int *count = (int *)context;
+
+	if (!acpi_is_root_bridge(handle))
+		return AE_OK;
+
+	(*count)++;
+
+	acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
+
+	acpi_install_notify_handler(handle, ACPI_SYSTEM_NOTIFY,
+				handle_hotplug_event_root, NULL);
+	printk(KERN_DEBUG "acpi root: %s notify handler installed\n", objname);
+
+	return AE_OK;
+}
+
+void __init acpi_pci_root_hp_init(void)
+{
+	int num = 0;
+
+	acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
+		ACPI_UINT32_MAX, find_root_bridges, NULL, &num, NULL);
+
+	printk(KERN_DEBUG "Found %d acpi root devices\n", num);
+}
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 7c43bdc36abc..bc2f33790e83 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -1706,5 +1706,8 @@ int __init acpi_scan_init(void)
 	}
 
 	acpi_update_all_gpes();
+
+	acpi_pci_root_hp_init();
+
 	return 0;
 }