acpiphp_glue.c

/*
 * ACPI PCI HotPlug glue functions to ACPI CA subsystem
 *
 * Copyright (C) 2002,2003 Takayoshi Kochi (t-kochi@bq.jp.nec.com)
 * Copyright (C) 2002 Hiroshi Aono (h-aono@ap.jp.nec.com)
 * Copyright (C) 2002,2003 NEC Corporation
 * Copyright (C) 2003-2005 Matthew Wilcox (matthew.wilcox@hp.com)
 * Copyright (C) 2003-2005 Hewlett Packard
 * Copyright (C) 2005 Rajesh Shah (rajesh.shah@intel.com)
 * Copyright (C) 2005 Intel Corporation
 *
 * All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or (at
 * your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
 * NON INFRINGEMENT.  See the GNU General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 * Send feedback to <kristen.c.accardi@intel.com>
 *
 */

/*
 * Lifetime rules for pci_dev:
 *  - The one in acpiphp_bridge has its refcount elevated by pci_get_slot()
 *    when the bridge is scanned and it loses a refcount when the bridge
 *    is removed.
 *  - When a P2P bridge is present, we elevate the refcount on the subordinate
 *    bus. It loses the refcount when the the driver unloads.
 */

#include <linux/init.h>
#include <linux/module.h>

#include <linux/kernel.h>
#include <linux/pci.h>
#include <linux/pci_hotplug.h>
#include <linux/pci-acpi.h>
#include <linux/mutex.h>

#include "../pci.h"
#include "acpiphp.h"

static LIST_HEAD(bridge_list);
static LIST_HEAD(ioapic_list);
static DEFINE_SPINLOCK(ioapic_list_lock);

#define MY_NAME "acpiphp_glue"

static void handle_hotplug_event_bridge (acpi_handle, u32, void *);
static void acpiphp_sanitize_bus(struct pci_bus *bus);
static void acpiphp_set_hpp_values(acpi_handle handle, struct pci_bus *bus);
static void handle_hotplug_event_func(acpi_handle handle, u32 type, void *context);

/* callback routine to check for the existence of a pci dock device */
static acpi_status
is_pci_dock_device(acpi_handle handle, u32 lvl, void *context, void **rv)
{
	int *count = (int *)context;

	if (is_dock_device(handle)) {
		(*count)++;
		return AE_CTRL_TERMINATE;
	} else {
		return AE_OK;
	}
}

/*
 * the _DCK method can do funny things... and sometimes not
 * hah-hah funny.
 *
 * TBD - figure out a way to only call fixups for
 * systems that require them.
 */
static int post_dock_fixups(struct notifier_block *nb, unsigned long val,
	void *v)
{
	struct acpiphp_func *func = container_of(nb, struct acpiphp_func, nb);
	struct pci_bus *bus = func->slot->bridge->pci_bus;
	u32 buses;

	if (!bus->self)
		return  NOTIFY_OK;

	/* fixup bad _DCK function that rewrites
	 * secondary bridge on slot
	 */
	pci_read_config_dword(bus->self,
			PCI_PRIMARY_BUS,
			&buses);

	if (((buses >> 8) & 0xff) != bus->secondary) {
		buses = (buses & 0xff000000)
			| ((unsigned int)(bus->primary)     <<  0)
			| ((unsigned int)(bus->secondary)   <<  8)
			| ((unsigned int)(bus->subordinate) << 16);
		pci_write_config_dword(bus->self, PCI_PRIMARY_BUS, buses);
	}
	return NOTIFY_OK;
}


static struct acpi_dock_ops acpiphp_dock_ops = {
	.handler = handle_hotplug_event_func,
};

/* callback routine to register each ACPI PCI slot object */
static acpi_status
register_slot(acpi_handle handle, u32 lvl, void *context, void **rv)
{
	struct acpiphp_bridge *bridge = (struct acpiphp_bridge *)context;
	struct acpiphp_slot *slot;
	struct acpiphp_func *newfunc;
	acpi_handle tmp;
	acpi_status status = AE_OK;
	unsigned long long adr, sun;
	int device, function, retval;
	struct pci_bus *pbus = bridge->pci_bus;
	struct pci_dev *pdev;

	if (!acpi_pci_check_ejectable(pbus, handle) && !is_dock_device(handle))
		return AE_OK;

	acpi_evaluate_integer(handle, "_ADR", NULL, &adr);
	device = (adr >> 16) & 0xffff;
	function = adr & 0xffff;

	newfunc = kzalloc(sizeof(struct acpiphp_func), GFP_KERNEL);
	if (!newfunc)
		return AE_NO_MEMORY;

	INIT_LIST_HEAD(&newfunc->sibling);
	newfunc->handle = handle;
	newfunc->function = function;

	if (ACPI_SUCCESS(acpi_get_handle(handle, "_EJ0", &tmp)))
		newfunc->flags = FUNC_HAS_EJ0;

	if (ACPI_SUCCESS(acpi_get_handle(handle, "_STA", &tmp)))
		newfunc->flags |= FUNC_HAS_STA;

	if (ACPI_SUCCESS(acpi_get_handle(handle, "_PS0", &tmp)))
		newfunc->flags |= FUNC_HAS_PS0;

	if (ACPI_SUCCESS(acpi_get_handle(handle, "_PS3", &tmp)))
		newfunc->flags |= FUNC_HAS_PS3;

	if (ACPI_SUCCESS(acpi_get_handle(handle, "_DCK", &tmp)))
		newfunc->flags |= FUNC_HAS_DCK;

	status = acpi_evaluate_integer(handle, "_SUN", NULL, &sun);
	if (ACPI_FAILURE(status)) {
		/*
		 * use the count of the number of slots we've found
		 * for the number of the slot
		 */
		sun = bridge->nr_slots+1;
	}

	/* search for objects that share the same slot */
	for (slot = bridge->slots; slot; slot = slot->next)
		if (slot->device == device) {
			if (slot->sun != sun)
				warn("sibling found, but _SUN doesn't match!\n");
			break;
		}

	if (!slot) {
		slot = kzalloc(sizeof(struct acpiphp_slot), GFP_KERNEL);
		if (!slot) {
			kfree(newfunc);
			return AE_NO_MEMORY;
		}

		slot->bridge = bridge;
		slot->device = device;
		slot->sun = sun;
		INIT_LIST_HEAD(&slot->funcs);
		mutex_init(&slot->crit_sect);

		slot->next = bridge->slots;
		bridge->slots = slot;

		bridge->nr_slots++;

		dbg("found ACPI PCI Hotplug slot %llu at PCI %04x:%02x:%02x\n",
		    slot->sun, pci_domain_nr(pbus), pbus->number, device);
		retval = acpiphp_register_hotplug_slot(slot);
		if (retval) {
			if (retval == -EBUSY)
				warn("Slot %llu already registered by another "
					"hotplug driver\n", slot->sun);
			else
				warn("acpiphp_register_hotplug_slot failed "
					"(err code = 0x%x)\n", retval);
			goto err_exit;
		}
	}

	newfunc->slot = slot;
	list_add_tail(&newfunc->sibling, &slot->funcs);

	pdev = pci_get_slot(pbus, PCI_DEVFN(device, function));
	if (pdev) {
		slot->flags |= (SLOT_ENABLED | SLOT_POWEREDON);
		pci_dev_put(pdev);
	}

	if (is_dock_device(handle)) {
		/* we don't want to call this device's _EJ0
		 * because we want the dock notify handler
		 * to call it after it calls _DCK
		 */
		newfunc->flags &= ~FUNC_HAS_EJ0;
		if (register_hotplug_dock_device(handle,
			&acpiphp_dock_ops, newfunc))
			dbg("failed to register dock device\n");

		/* we need to be notified when dock events happen
		 * outside of the hotplug operation, since we may
		 * need to do fixups before we can hotplug.
		 */
		newfunc->nb.notifier_call = post_dock_fixups;
		if (register_dock_notifier(&newfunc->nb))
			dbg("failed to register a dock notifier");
	}

	/* install notify handler */
	if (!(newfunc->flags & FUNC_HAS_DCK)) {
		status = acpi_install_notify_handler(handle,
					     ACPI_SYSTEM_NOTIFY,
					     handle_hotplug_event_func,
					     newfunc);

		if (ACPI_FAILURE(status))
			err("failed to register interrupt notify handler\n");
	} else
		status = AE_OK;

	return status;

 err_exit:
	bridge->nr_slots--;
	bridge->slots = slot->next;
	kfree(slot);
	kfree(newfunc);

	return AE_OK;
}


/* see if it's worth looking at this bridge */
static int detect_ejectable_slots(acpi_handle handle)
{
	int found = acpi_pci_detect_ejectable(handle);
	if (!found) {
		acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, (u32)1,
				    is_pci_dock_device, (void *)&found, NULL);
	}
	return found;
}


/* decode ACPI 2.0 _HPP hot plug parameters */
static void decode_hpp(struct acpiphp_bridge *bridge)
{
	acpi_status status;

	status = acpi_get_hp_params_from_firmware(bridge->pci_bus, &bridge->hpp);
	if (ACPI_FAILURE(status) ||
	    !bridge->hpp.t0 || (bridge->hpp.t0->revision > 1)) {
		/* use default numbers */
		printk(KERN_WARNING
		       "%s: Could not get hotplug parameters. Use defaults\n",
		       __func__);
		bridge->hpp.t0 = &bridge->hpp.type0_data;
		bridge->hpp.t0->revision = 0;
		bridge->hpp.t0->cache_line_size = 0x10;
		bridge->hpp.t0->latency_timer = 0x40;
		bridge->hpp.t0->enable_serr = 0;
		bridge->hpp.t0->enable_perr = 0;
	}
}



/* initialize miscellaneous stuff for both root and PCI-to-PCI bridge */
static void init_bridge_misc(struct acpiphp_bridge *bridge)
{
	acpi_status status;

	/* must be added to the list prior to calling register_slot */
	list_add(&bridge->list, &bridge_list);

	/* register all slot objects under this bridge */
	status = acpi_walk_namespace(ACPI_TYPE_DEVICE, bridge->handle, (u32)1,
				     register_slot, bridge, NULL);
	if (ACPI_FAILURE(status)) {
		list_del(&bridge->list);
		return;
	}

	/* install notify handler */
	if (bridge->type != BRIDGE_TYPE_HOST) {
		if ((bridge->flags & BRIDGE_HAS_EJ0) && bridge->func) {
			status = acpi_remove_notify_handler(bridge->func->handle,
						ACPI_SYSTEM_NOTIFY,
						handle_hotplug_event_func);
			if (ACPI_FAILURE(status))
				err("failed to remove notify handler\n");
		}
		status = acpi_install_notify_handler(bridge->handle,
					     ACPI_SYSTEM_NOTIFY,
					     handle_hotplug_event_bridge,
					     bridge);

		if (ACPI_FAILURE(status)) {
			err("failed to register interrupt notify handler\n");
		}
	}
}


/* find acpiphp_func from acpiphp_bridge */
static struct acpiphp_func *acpiphp_bridge_handle_to_function(acpi_handle handle)
{
	struct list_head *node, *l;
	struct acpiphp_bridge *bridge;
	struct acpiphp_slot *slot;
	struct acpiphp_func *func;

	list_for_each(node, &bridge_list) {
		bridge = list_entry(node, struct acpiphp_bridge, list);
		for (slot = bridge->slots; slot; slot = slot->next) {
			list_for_each(l, &slot->funcs) {
				func = list_entry(l, struct acpiphp_func,
							sibling);
				if (func->handle == handle)
					return func;
			}
		}
	}

	return NULL;
}


static inline void config_p2p_bridge_flags(struct acpiphp_bridge *bridge)
{
	acpi_handle dummy_handle;

	if (ACPI_SUCCESS(acpi_get_handle(bridge->handle,
					"_STA", &dummy_handle)))
		bridge->flags |= BRIDGE_HAS_STA;

	if (ACPI_SUCCESS(acpi_get_handle(bridge->handle,
					"_EJ0", &dummy_handle)))
		bridge->flags |= BRIDGE_HAS_EJ0;

	if (ACPI_SUCCESS(acpi_get_handle(bridge->handle,
					"_PS0", &dummy_handle)))
		bridge->flags |= BRIDGE_HAS_PS0;

	if (ACPI_SUCCESS(acpi_get_handle(bridge->handle,
					"_PS3", &dummy_handle)))
		bridge->flags |= BRIDGE_HAS_PS3;

	/* is this ejectable p2p bridge? */
	if (bridge->flags & BRIDGE_HAS_EJ0) {
		struct acpiphp_func *func;

		dbg("found ejectable p2p bridge\n");

		/* make link between PCI bridge and PCI function */
		func = acpiphp_bridge_handle_to_function(bridge->handle);
		if (!func)
			return;
		bridge->func = func;
		func->bridge = bridge;
	}
}


/* allocate and initialize host bridge data structure */
static void add_host_bridge(acpi_handle *handle)
{
	struct acpiphp_bridge *bridge;
	struct acpi_pci_root *root = acpi_pci_find_root(handle);

	bridge = kzalloc(sizeof(struct acpiphp_bridge), GFP_KERNEL);
	if (bridge == NULL)
		return;

	bridge->type = BRIDGE_TYPE_HOST;
	bridge->handle = handle;

	bridge->pci_bus = root->bus;

	spin_lock_init(&bridge->res_lock);

	init_bridge_misc(bridge);
}


/* allocate and initialize PCI-to-PCI bridge data structure */
static void add_p2p_bridge(acpi_handle *handle)
{
	struct acpiphp_bridge *bridge;

	bridge = kzalloc(sizeof(struct acpiphp_bridge), GFP_KERNEL);
	if (bridge == NULL) {
		err("out of memory\n");
		return;
	}

	bridge->type = BRIDGE_TYPE_P2P;
	bridge->handle = handle;
	config_p2p_bridge_flags(bridge);

	bridge->pci_dev = acpi_get_pci_dev(handle);
	bridge->pci_bus = bridge->pci_dev->subordinate;
	if (!bridge->pci_bus) {
		err("This is not a PCI-to-PCI bridge!\n");
		goto err;
	}

	/*
	 * Grab a ref to the subordinate PCI bus in case the bus is
	 * removed via PCI core logical hotplug. The ref pins the bus
	 * (which we access during module unload).
	 */
	get_device(&bridge->pci_bus->dev);
	spin_lock_init(&bridge->res_lock);

	init_bridge_misc(bridge);
	return;
 err:
	pci_dev_put(bridge->pci_dev);
	kfree(bridge);
	return;
}


/* callback routine to find P2P bridges */
static acpi_status
find_p2p_bridge(acpi_handle handle, u32 lvl, void *context, void **rv)
{
	acpi_status status;
	struct pci_dev *dev;

	dev = acpi_get_pci_dev(handle);
	if (!dev || !dev->subordinate)
		goto out;

	/* check if this bridge has ejectable slots */
	if ((detect_ejectable_slots(handle) > 0)) {
		dbg("found PCI-to-PCI bridge at PCI %s\n", pci_name(dev));
		add_p2p_bridge(handle);
	}

	/* search P2P bridges under this p2p bridge */
	status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, (u32)1,
				     find_p2p_bridge, NULL, NULL);
	if (ACPI_FAILURE(status))
		warn("find_p2p_bridge failed (error code = 0x%x)\n", status);

 out:
	pci_dev_put(dev);
	return AE_OK;
}


/* find hot-pluggable slots, and then find P2P bridge */
static int add_bridge(acpi_handle handle)
{
	acpi_status status;
	unsigned long long tmp;
	acpi_handle dummy_handle;

	/* if the bridge doesn't have _STA, we assume it is always there */
	status = acpi_get_handle(handle, "_STA", &dummy_handle);
	if (ACPI_SUCCESS(status)) {
		status = acpi_evaluate_integer(handle, "_STA", NULL, &tmp);
		if (ACPI_FAILURE(status)) {
			dbg("%s: _STA evaluation failure\n", __func__);
			return 0;
		}
		if ((tmp & ACPI_STA_FUNCTIONING) == 0)
			/* don't register this object */
			return 0;
	}

	/* check if this bridge has ejectable slots */
	if (detect_ejectable_slots(handle) > 0) {
		dbg("found PCI host-bus bridge with hot-pluggable slots\n");
		add_host_bridge(handle);
	}

	/* search P2P bridges under this host bridge */
	status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, (u32)1,
				     find_p2p_bridge, NULL, NULL);

	if (ACPI_FAILURE(status))
		warn("find_p2p_bridge failed (error code = 0x%x)\n", status);

	return 0;
}

static struct acpiphp_bridge *acpiphp_handle_to_bridge(acpi_handle handle)
{
	struct list_head *head;
	list_for_each(head, &bridge_list) {
		struct acpiphp_bridge *bridge = list_entry(head,
						struct acpiphp_bridge, list);
		if (bridge->handle == handle)
			return bridge;
	}

	return NULL;
}

static void cleanup_bridge(struct acpiphp_bridge *bridge)
{
	struct list_head *list, *tmp;
	struct acpiphp_slot *slot;
	acpi_status status;
	acpi_handle handle = bridge->handle;

	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 ((bridge->type != BRIDGE_TYPE_HOST) &&
	    ((bridge->flags & BRIDGE_HAS_EJ0) && bridge->func)) {
		status = acpi_install_notify_handler(bridge->func->handle,
						ACPI_SYSTEM_NOTIFY,
						handle_hotplug_event_func,
						bridge->func);
		if (ACPI_FAILURE(status))
			err("failed to install interrupt notify handler\n");
	}

	slot = bridge->slots;
	while (slot) {
		struct acpiphp_slot *next = slot->next;
		list_for_each_safe (list, tmp, &slot->funcs) {
			struct acpiphp_func *func;
			func = list_entry(list, struct acpiphp_func, sibling);
			if (is_dock_device(func->handle)) {
				unregister_hotplug_dock_device(func->handle);
				unregister_dock_notifier(&func->nb);
			}
			if (!(func->flags & FUNC_HAS_DCK)) {
				status = acpi_remove_notify_handler(func->handle,
						ACPI_SYSTEM_NOTIFY,
						handle_hotplug_event_func);
				if (ACPI_FAILURE(status))
					err("failed to remove notify handler\n");
			}
			list_del(list);
			kfree(func);
		}
		acpiphp_unregister_hotplug_slot(slot);
		list_del(&slot->funcs);
		kfree(slot);
		slot = next;
	}

	/*
	 * Only P2P bridges have a pci_dev
	 */
	if (bridge->pci_dev)
		put_device(&bridge->pci_bus->dev);

	pci_dev_put(bridge->pci_dev);
	list_del(&bridge->list);
	kfree(bridge);
}

static acpi_status
cleanup_p2p_bridge(acpi_handle handle, u32 lvl, void *context, void **rv)
{
	struct acpiphp_bridge *bridge;

	/* cleanup p2p bridges under this P2P bridge
	   in a depth-first manner */
	acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, (u32)1,
				cleanup_p2p_bridge, NULL, NULL);

	bridge = acpiphp_handle_to_bridge(handle);
	if (bridge)
		cleanup_bridge(bridge);

	return AE_OK;
}

static void remove_bridge(acpi_handle handle)
{
	struct acpiphp_bridge *bridge;

	/* cleanup p2p bridges under this host bridge
	   in a depth-first manner */
	acpi_walk_namespace(ACPI_TYPE_DEVICE, handle,
				(u32)1, cleanup_p2p_bridge, NULL, NULL);

	/*
	 * On root bridges with hotplug slots directly underneath (ie,
	 * no p2p bridge inbetween), we call cleanup_bridge(). 
	 *
	 * The else clause cleans up root bridges that either had no
	 * hotplug slots at all, or had a p2p bridge underneath.
	 */
	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 struct pci_dev * get_apic_pci_info(acpi_handle handle)
{
	struct pci_dev *dev;

	dev = acpi_get_pci_dev(handle);
	if (!dev)
		return NULL;

	if ((dev->class != PCI_CLASS_SYSTEM_PIC_IOAPIC) &&
	    (dev->class != PCI_CLASS_SYSTEM_PIC_IOXAPIC))
	{
		pci_dev_put(dev);
		return NULL;
	}

	return dev;
}

static int get_gsi_base(acpi_handle handle, u32 *gsi_base)
{
	acpi_status status;
	int result = -1;
	unsigned long long gsb;
	struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL};
	union acpi_object *obj;
	void *table;

	status = acpi_evaluate_integer(handle, "_GSB", NULL, &gsb);
	if (ACPI_SUCCESS(status)) {
		*gsi_base = (u32)gsb;
		return 0;
	}

	status = acpi_evaluate_object(handle, "_MAT", NULL, &buffer);
	if (ACPI_FAILURE(status) || !buffer.length || !buffer.pointer)
		return -1;

	obj = buffer.pointer;
	if (obj->type != ACPI_TYPE_BUFFER)
		goto out;

	table = obj->buffer.pointer;
	switch (((struct acpi_subtable_header *)table)->type) {
	case ACPI_MADT_TYPE_IO_SAPIC:
		*gsi_base = ((struct acpi_madt_io_sapic *)table)->global_irq_base;
		result = 0;
		break;
	case ACPI_MADT_TYPE_IO_APIC:
		*gsi_base = ((struct acpi_madt_io_apic *)table)->global_irq_base;
		result = 0;
		break;
	default:
		break;
	}
 out:
	kfree(buffer.pointer);
	return result;
}

static acpi_status
ioapic_add(acpi_handle handle, u32 lvl, void *context, void **rv)
{
	acpi_status status;
	unsigned long long sta;
	acpi_handle tmp;
	struct pci_dev *pdev;
	u32 gsi_base;
	u64 phys_addr;
	struct acpiphp_ioapic *ioapic;

	/* Evaluate _STA if present */
	status = acpi_evaluate_integer(handle, "_STA", NULL, &sta);
	if (ACPI_SUCCESS(status) && sta != ACPI_STA_ALL)
		return AE_CTRL_DEPTH;

	/* Scan only PCI bus scope */
	status = acpi_get_handle(handle, "_HID", &tmp);
	if (ACPI_SUCCESS(status))
		return AE_CTRL_DEPTH;

	if (get_gsi_base(handle, &gsi_base))
		return AE_OK;

	ioapic = kmalloc(sizeof(*ioapic), GFP_KERNEL);
	if (!ioapic)
		return AE_NO_MEMORY;

	pdev = get_apic_pci_info(handle);
	if (!pdev)
		goto exit_kfree;

	if (pci_enable_device(pdev))
		goto exit_pci_dev_put;

	pci_set_master(pdev);

	if (pci_request_region(pdev, 0, "I/O APIC(acpiphp)"))
		goto exit_pci_disable_device;

	phys_addr = pci_resource_start(pdev, 0);
	if (acpi_register_ioapic(handle, phys_addr, gsi_base))
		goto exit_pci_release_region;

	ioapic->gsi_base = gsi_base;
	ioapic->dev = pdev;
	spin_lock(&ioapic_list_lock);
	list_add_tail(&ioapic->list, &ioapic_list);
	spin_unlock(&ioapic_list_lock);

	return AE_OK;

 exit_pci_release_region:
	pci_release_region(pdev, 0);
 exit_pci_disable_device:
	pci_disable_device(pdev);
 exit_pci_dev_put:
	pci_dev_put(pdev);
 exit_kfree:
	kfree(ioapic);

	return AE_OK;
}

static acpi_status
ioapic_remove(acpi_handle handle, u32 lvl, void *context, void **rv)
{
	acpi_status status;
	unsigned long long sta;
	acpi_handle tmp;
	u32 gsi_base;
	struct acpiphp_ioapic *pos, *n, *ioapic = NULL;

	/* Evaluate _STA if present */
	status = acpi_evaluate_integer(handle, "_STA", NULL, &sta);
	if (ACPI_SUCCESS(status) && sta != ACPI_STA_ALL)
		return AE_CTRL_DEPTH;

	/* Scan only PCI bus scope */
	status = acpi_get_handle(handle, "_HID", &tmp);
	if (ACPI_SUCCESS(status))
		return AE_CTRL_DEPTH;

	if (get_gsi_base(handle, &gsi_base))
		return AE_OK;

	acpi_unregister_ioapic(handle, gsi_base);

	spin_lock(&ioapic_list_lock);
	list_for_each_entry_safe(pos, n, &ioapic_list, list) {
		if (pos->gsi_base != gsi_base)
			continue;
		ioapic = pos;
		list_del(&ioapic->list);
		break;
	}
	spin_unlock(&ioapic_list_lock);

	if (!ioapic)
		return AE_OK;

	pci_release_region(ioapic->dev, 0);
	pci_disable_device(ioapic->dev);
	pci_dev_put(ioapic->dev);
	kfree(ioapic);

	return AE_OK;
}

static int acpiphp_configure_ioapics(acpi_handle handle)
{
	ioapic_add(handle, 0, NULL, NULL);
	acpi_walk_namespace(ACPI_TYPE_DEVICE, handle,
			    ACPI_UINT32_MAX, ioapic_add, NULL, NULL);
	return 0;
}

static int acpiphp_unconfigure_ioapics(acpi_handle handle)
{
	ioapic_remove(handle, 0, NULL, NULL);
	acpi_walk_namespace(ACPI_TYPE_DEVICE, handle,
			    ACPI_UINT32_MAX, ioapic_remove, NULL, NULL);
	return 0;
}

static int power_on_slot(struct acpiphp_slot *slot)
{
	acpi_status status;
	struct acpiphp_func *func;
	struct list_head *l;
	int retval = 0;

	/* if already enabled, just skip */
	if (slot->flags & SLOT_POWEREDON)
		goto err_exit;

	list_for_each (l, &slot->funcs) {
		func = list_entry(l, struct acpiphp_func, sibling);

		if (func->flags & FUNC_HAS_PS0) {
			dbg("%s: executing _PS0\n", __func__);
			status = acpi_evaluate_object(func->handle, "_PS0", NULL, NULL);
			if (ACPI_FAILURE(status)) {
				warn("%s: _PS0 failed\n", __func__);
				retval = -1;
				goto err_exit;
			} else
				break;
		}
	}

	/* TBD: evaluate _STA to check if the slot is enabled */

	slot->flags |= SLOT_POWEREDON;

 err_exit:
	return retval;
}


static int power_off_slot(struct acpiphp_slot *slot)
{
	acpi_status status;
	struct acpiphp_func *func;
	struct list_head *l;

	int retval = 0;

	/* if already disabled, just skip */
	if ((slot->flags & SLOT_POWEREDON) == 0)
		goto err_exit;

	list_for_each (l, &slot->funcs) {
		func = list_entry(l, struct acpiphp_func, sibling);

		if (func->flags & FUNC_HAS_PS3) {
			status = acpi_evaluate_object(func->handle, "_PS3", NULL, NULL);
			if (ACPI_FAILURE(status)) {
				warn("%s: _PS3 failed\n", __func__);
				retval = -1;
				goto err_exit;
			} else
				break;
		}
	}

	/* TBD: evaluate _STA to check if the slot is disabled */

	slot->flags &= (~SLOT_POWEREDON);

 err_exit:
	return retval;
}



/**
 * acpiphp_max_busnr - return the highest reserved bus number under the given bus.
 * @bus: bus to start search with
 */
static unsigned char acpiphp_max_busnr(struct pci_bus *bus)
{
	struct list_head *tmp;
	unsigned char max, n;

	/*
	 * pci_bus_max_busnr will return the highest
	 * reserved busnr for all these children.
	 * that is equivalent to the bus->subordinate
	 * value.  We don't want to use the parent's
	 * bus->subordinate value because it could have
	 * padding in it.
	 */
	max = bus->secondary;

	list_for_each(tmp, &bus->children) {
		n = pci_bus_max_busnr(pci_bus_b(tmp));
		if (n > max)
			max = n;
	}
	return max;
}


/**
 * acpiphp_bus_add - add a new bus to acpi subsystem
 * @func: acpiphp_func of the bridge
 */
static int acpiphp_bus_add(struct acpiphp_func *func)
{
	acpi_handle phandle;
	struct acpi_device *device, *pdevice;
	int ret_val;

	acpi_get_parent(func->handle, &phandle);
	if (acpi_bus_get_device(phandle, &pdevice)) {
		dbg("no parent device, assuming NULL\n");
		pdevice = NULL;
	}
	if (!acpi_bus_get_device(func->handle, &device)) {
		dbg("bus exists... trim\n");
		/* this shouldn't be in here, so remove
		 * the bus then re-add it...
		 */
		ret_val = acpi_bus_trim(device, 1);
		dbg("acpi_bus_trim return %x\n", ret_val);
	}

	ret_val = acpi_bus_add(&device, pdevice, func->handle,
		ACPI_BUS_TYPE_DEVICE);
	if (ret_val) {
		dbg("error adding bus, %x\n",
			-ret_val);
		goto acpiphp_bus_add_out;
	}
	/*
	 * try to start anyway.  We could have failed to add
	 * simply because this bus had previously been added
	 * on another add.  Don't bother with the return value
	 * we just keep going.
	 */
	ret_val = acpi_bus_start(device);

acpiphp_bus_add_out:
	return ret_val;
}


/**
 * acpiphp_bus_trim - trim a bus from acpi subsystem
 * @handle: handle to acpi namespace
 */
static int acpiphp_bus_trim(acpi_handle handle)
{
	struct acpi_device *device;
	int retval;

	retval = acpi_bus_get_device(handle, &device);
	if (retval) {
		dbg("acpi_device not found\n");
		return retval;
	}

	retval = acpi_bus_trim(device, 1);
	if (retval)
		err("cannot remove from acpi list\n");

	return retval;
}

/**
 * enable_device - enable, configure a slot
 * @slot: slot to be enabled
 *
 * This function should be called per *physical slot*,
 * not per each slot object in ACPI namespace.
 */
static int __ref enable_device(struct acpiphp_slot *slot)
{
	struct pci_dev *dev;
	struct pci_bus *bus = slot->bridge->pci_bus;
	struct list_head *l;
	struct acpiphp_func *func;
	int retval = 0;
	int num, max, pass;
	acpi_status status;

	if (slot->flags & SLOT_ENABLED)
		goto err_exit;