Merge master.kernel.org:/pub/scm/linux/kernel/git/wim/linux-2.6-watchdog

[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / drivers / pci / hotplug / 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 <t-kochi@bq.jp.nec.com>
 *
 */

/*
 * Lifetime rules for pci_dev:
 *  - The one in acpiphp_func has its refcount elevated by pci_get_slot()
 *    when the driver is loaded or when an insertion event occurs.  It loses
 *    a refcount when its ejected or the driver unloads.
 *  - 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.
 */

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

#include <linux/kernel.h>
#include <linux/pci.h>
#include <linux/smp_lock.h>
#include <linux/mutex.h>

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

static LIST_HEAD(bridge_list);

#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);


/*
 * initialization & terminatation routines
 */

/**
 * is_ejectable - determine if a slot is ejectable
 * @handle: handle to acpi namespace
 *
 * Ejectable slot should satisfy at least these conditions:
 *
 *  1. has _ADR method
 *  2. has _EJ0 method
 *
 * optionally
 *
 *  1. has _STA method
 *  2. has _PS0 method
 *  3. has _PS3 method
 *  4. ..
 *
 */
static int is_ejectable(acpi_handle handle)
{
        acpi_status status;
        acpi_handle tmp;

        status = acpi_get_handle(handle, "_ADR", &tmp);
        if (ACPI_FAILURE(status)) {
                return 0;
        }

        status = acpi_get_handle(handle, "_EJ0", &tmp);
        if (ACPI_FAILURE(status)) {
                return 0;
        }

        return 1;
}


/* callback routine to check the existence of ejectable slots */
static acpi_status
is_ejectable_slot(acpi_handle handle, u32 lvl, void *context, void **rv)
{
        int *count = (int *)context;

        if (is_ejectable(handle)) {
                (*count)++;
                /* only one ejectable slot is enough */
                return AE_CTRL_TERMINATE;
        } else {
                return AE_OK;
        }
}


/* 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;
        struct dependent_device *dd;
        acpi_handle tmp;
        acpi_status status = AE_OK;
        unsigned long adr, sun;
        int device, function, retval;

        status = acpi_evaluate_integer(handle, "_ADR", NULL, &adr);

        if (ACPI_FAILURE(status))
                return AE_OK;

        status = acpi_get_handle(handle, "_EJ0", &tmp);

        if (ACPI_FAILURE(status) && !(is_dependent_device(handle)))
                return AE_OK;

        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(status))
                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;
                /* add to devices dependent on dock station,
                 * because this may actually be the dock bridge
                 */
                dd = alloc_dependent_device(handle);
                if (!dd)
                        err("Can't allocate memory for "
                                "new dependent device!\n");
                else
                        add_dependent_device(dd);
        }

        status = acpi_evaluate_integer(handle, "_SUN", NULL, &sun);
        if (ACPI_FAILURE(status))
                sun = -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 %d at PCI %04x:%02x:%02x\n",
                                slot->sun, pci_domain_nr(bridge->pci_bus),
                                bridge->pci_bus->number, slot->device);
                retval = acpiphp_register_hotplug_slot(slot);
                if (retval) {
                        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);

        /* associate corresponding pci_dev */
        newfunc->pci_dev = pci_get_slot(bridge->pci_bus,
                                         PCI_DEVFN(device, function));
        if (newfunc->pci_dev) {
                slot->flags |= (SLOT_ENABLED | SLOT_POWEREDON);
        }

        /* if this is a device dependent on a dock station,
         * associate the acpiphp_func to the dependent_device
         * struct.
         */
        if ((dd = get_dependent_device(handle))) {
                newfunc->flags |= FUNC_IS_DD;
                /*
                 * we don't want any devices which is dependent
                 * on the dock to have it's _EJ0 method executed.
                 * because we need to run _DCK first.
                 */
                newfunc->flags &= ~FUNC_HAS_EJ0;
                dd->func = newfunc;
                add_pci_dependent_device(dd);
        }

        /* 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 *bridge_handle)
{
        acpi_status status;
        int count;

        count = 0;

        /* only check slots defined directly below bridge object */
        status = acpi_walk_namespace(ACPI_TYPE_DEVICE, bridge_handle, (u32)1,
                                     is_ejectable_slot, (void *)&count, NULL);

        return count;
}


/* 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_dev, &bridge->hpp);
        if (ACPI_FAILURE(status)) {
                /* use default numbers */
                bridge->hpp.cache_line_size = 0x10;
                bridge->hpp.latency_timer = 0x40;
                bridge->hpp.enable_serr = 0;
                bridge->hpp.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;

        /* decode ACPI 2.0 _HPP (hot plug parameters) */
        decode_hpp(bridge);

        /* 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) {
                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");
                }
        }
}


/* allocate and initialize host bridge data structure */
static void add_host_bridge(acpi_handle *handle, struct pci_bus *pci_bus)
{
        struct acpiphp_bridge *bridge;

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

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

        bridge->pci_bus = pci_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 pci_dev *pci_dev)
{
        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;

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

        spin_lock_init(&bridge->res_lock);

        init_bridge_misc(bridge);
        return;
 err:
        pci_dev_put(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;
        acpi_handle dummy_handle;
        unsigned long tmp;
        int device, function;
        struct pci_dev *dev;
        struct pci_bus *pci_bus = context;

        status = acpi_get_handle(handle, "_ADR", &dummy_handle);
        if (ACPI_FAILURE(status))
                return AE_OK;           /* continue */

        status = acpi_evaluate_integer(handle, "_ADR", NULL, &tmp);
        if (ACPI_FAILURE(status)) {
                dbg("%s: _ADR evaluation failure\n", __FUNCTION__);
                return AE_OK;
        }

        device = (tmp >> 16) & 0xffff;
        function = tmp & 0xffff;

        dev = pci_get_slot(pci_bus, PCI_DEVFN(device, function));

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

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

        /* search P2P bridges under this p2p bridge */
        status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, (u32)1,
                                     find_p2p_bridge, dev->subordinate, NULL);
        if (ACPI_FAILURE(status))
                warn("find_p2p_bridge faied (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 tmp;
        int seg, bus;
        acpi_handle dummy_handle;
        struct pci_bus *pci_bus;

        /* 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", __FUNCTION__);
                        return 0;
                }
                if ((tmp & ACPI_STA_FUNCTIONING) == 0)
                        /* don't register this object */
                        return 0;
        }

        /* get PCI segment number */
        status = acpi_evaluate_integer(handle, "_SEG", NULL, &tmp);

        seg = ACPI_SUCCESS(status) ? tmp : 0;

        /* get PCI bus number */
        status = acpi_evaluate_integer(handle, "_BBN", NULL, &tmp);

        if (ACPI_SUCCESS(status)) {
                bus = tmp;
        } else {
                warn("can't get bus number, assuming 0\n");
                bus = 0;
        }

        pci_bus = pci_find_bus(seg, bus);
        if (!pci_bus) {
                err("Can't find bus %04x:%02x\n", seg, bus);
                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, pci_bus);
                return 0;
        }

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

        if (ACPI_FAILURE(status))
                warn("find_p2p_bridge faied (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");

        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 (!(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");
                        }
                        pci_dev_put(func->pci_dev);
                        list_del(list);
                        kfree(func);
                }
                acpiphp_unregister_hotplug_slot(slot);
                list_del(&slot->funcs);
                kfree(slot);
                slot = next;
        }

        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;

        if (!(bridge = acpiphp_handle_to_bridge(handle)))
                return AE_OK;
        cleanup_bridge(bridge);
        return AE_OK;
}

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

        bridge = acpiphp_handle_to_bridge(handle);
        if (bridge) {
                cleanup_bridge(bridge);
        } else {
                /* clean-up p2p bridges under this host bridge */
                acpi_walk_namespace(ACPI_TYPE_DEVICE, handle,
                                    ACPI_UINT32_MAX, cleanup_p2p_bridge,
                                    NULL, NULL);
        }
}

static struct pci_dev * get_apic_pci_info(acpi_handle handle)
{
        struct acpi_pci_id id;
        struct pci_bus *bus;
        struct pci_dev *dev;

        if (ACPI_FAILURE(acpi_get_pci_id(handle, &id)))
                return NULL;

        bus = pci_find_bus(id.segment, id.bus);
        if (!bus)
                return NULL;

        dev = pci_get_slot(bus, PCI_DEVFN(id.device, id.function));
        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 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 (((acpi_table_entry_header *)table)->type) {
        case ACPI_MADT_IOSAPIC:
                *gsi_base = ((struct acpi_table_iosapic *)table)->global_irq_base;
                result = 0;
                break;
        case ACPI_MADT_IOAPIC:
                *gsi_base = ((struct acpi_table_ioapic *)table)->global_irq_base;
                result = 0;
                break;
        default:
                break;
        }
 out:
        acpi_os_free(buffer.pointer);
        return result;
}

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

        /* 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;

        pdev = get_apic_pci_info(handle);
        if (!pdev)
                return AE_OK;

        if (pci_enable_device(pdev)) {
                pci_dev_put(pdev);
                return AE_OK;
        }

        pci_set_master(pdev);

        if (pci_request_region(pdev, 0, "I/O APIC(acpiphp)")) {
                pci_disable_device(pdev);
                pci_dev_put(pdev);
                return AE_OK;
        }

        phys_addr = pci_resource_start(pdev, 0);
        if (acpi_register_ioapic(handle, phys_addr, gsi_base)) {
                pci_release_region(pdev, 0);
                pci_disable_device(pdev);
                pci_dev_put(pdev);
                return AE_OK;
        }

        return AE_OK;
}

static int acpiphp_configure_ioapics(acpi_handle handle)
{
        acpi_walk_namespace(ACPI_TYPE_DEVICE, handle,
                            ACPI_UINT32_MAX, ioapic_add, 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", __FUNCTION__);
                        status = acpi_evaluate_object(func->handle, "_PS0", NULL, NULL);
                        if (ACPI_FAILURE(status)) {
                                warn("%s: _PS0 failed\n", __FUNCTION__);
                                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", __FUNCTION__);
                                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;
}



/**
 *  get_func - get a pointer to acpiphp_func given a slot, device
 *  @slot: slot to search
 *  @dev:  pci_dev struct to match.
 *
 *  This function will increase the reference count of pci_dev,
 *  so callers should call pci_dev_put when complete.
 *
 */
static struct acpiphp_func *
get_func(struct acpiphp_slot *slot, struct pci_dev *dev)
{
        struct acpiphp_func *func = NULL;
        struct pci_bus *bus = slot->bridge->pci_bus;
        struct pci_dev *pdev;

        list_for_each_entry(func, &slot->funcs, sibling) {
                pdev = pci_get_slot(bus, PCI_DEVFN(slot->device,
                                        func->function));
                if (pdev) {
                        if (pdev == dev)
                                break;
                        pci_dev_put(pdev);
                }
        }
        return func;
}


/**
 * 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;
}



/**
 * 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 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;

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

        /* sanity check: dev should be NULL when hot-plugged in */
        dev = pci_get_slot(bus, PCI_DEVFN(slot->device, 0));
        if (dev) {
                /* This case shouldn't happen */
                err("pci_dev structure already exists.\n");
                pci_dev_put(dev);
                retval = -1;
                goto err_exit;
        }

        num = pci_scan_slot(bus, PCI_DEVFN(slot->device, 0));
        if (num == 0) {
                err("No new device found\n");
                retval = -1;
                goto err_exit;
        }

        max = acpiphp_max_busnr(bus);
        for (pass = 0; pass < 2; pass++) {
                list_for_each_entry(dev, &bus->devices, bus_list) {
                        if (PCI_SLOT(dev->devfn) != slot->device)
                                continue;
                        if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE ||
                            dev->hdr_type == PCI_HEADER_TYPE_CARDBUS) {
                                max = pci_scan_bridge(bus, dev, max, pass);
                                if (pass && dev->subordinate) {
                                        pci_bus_size_bridges(dev->subordinate);
                                        func = get_func(slot, dev);
                                        if (func) {
                                                acpiphp_bus_add(func);
                                                /* side effect of get_func */
                                                pci_dev_put(dev);
                                        }
                                }
                        }
                }
        }

        pci_bus_assign_resources(bus);
        acpiphp_sanitize_bus(bus);
        pci_enable_bridges(bus);
        pci_bus_add_devices(bus);
        acpiphp_set_hpp_values(slot->bridge->handle, bus);
        acpiphp_configure_ioapics(slot->bridge->handle);

        /* associate pci_dev to our representation */
        list_for_each (l, &slot->funcs) {
                func = list_entry(l, struct acpiphp_func, sibling);
                func->pci_dev = pci_get_slot(bus, PCI_DEVFN(slot->device,
                                                        func->function));
        }

        slot->flags |= SLOT_ENABLED;

 err_exit:
        return retval;
}


/**
 * disable_device - disable a slot
 */
static int disable_device(struct acpiphp_slot *slot)
{
        int retval = 0;
        struct acpiphp_func *func;
        struct list_head *l;

        /* is this slot already disabled? */
        if (!(slot->flags & SLOT_ENABLED))
                goto err_exit;

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

                pci_remove_bus_device(func->pci_dev);
                pci_dev_put(func->pci_dev);
                func->pci_dev = NULL;
        }

        slot->flags &= (~SLOT_ENABLED);

 err_exit:
        return retval;
}


/**
 * get_slot_status - get ACPI slot status
 *
 * if a slot has _STA for each function and if any one of them
 * returned non-zero status, return it
 *
 * if a slot doesn't have _STA and if any one of its functions'
 * configuration space is configured, return 0x0f as a _STA
 *
 * otherwise return 0
 */
static unsigned int get_slot_status(struct acpiphp_slot *slot)
{
        acpi_status status;
        unsigned long sta = 0;
        u32 dvid;
        struct list_head *l;
        struct acpiphp_func *func;

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

                if (func->flags & FUNC_HAS_STA) {
                        status = acpi_evaluate_integer(func->handle, "_STA", NULL, &sta);
                        if (ACPI_SUCCESS(status) && sta)
                                break;
                } else {
                        pci_bus_read_config_dword(slot->bridge->pci_bus,
                                                  PCI_DEVFN(slot->device,
                                                            func->function),
                                                  PCI_VENDOR_ID, &dvid);
                        if (dvid != 0xffffffff) {
                                sta = ACPI_STA_ALL;
                                break;
                        }
                }
        }

        return (unsigned int)sta;
}

/**
 * acpiphp_eject_slot - physically eject the slot
 */
static int acpiphp_eject_slot(struct acpiphp_slot *slot)
{
        acpi_status status;
        struct acpiphp_func *func;
        struct list_head *l;
        struct acpi_object_list arg_list;
        union acpi_object arg;

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

                /* We don't want to call _EJ0 on non-existing functions. */
                if ((func->flags & FUNC_HAS_EJ0)) {
                        /* _EJ0 method take one argument */
                        arg_list.count = 1;
                        arg_list.pointer = &arg;
                        arg.type = ACPI_TYPE_INTEGER;
                        arg.integer.value = 1;

                        status = acpi_evaluate_object(func->handle, "_EJ0", &arg_list, NULL);
                        if (ACPI_FAILURE(status)) {
                                warn("%s: _EJ0 failed\n", __FUNCTION__);
                                return -1;
                        } else
                                break;
                }
        }
        return 0;
}

/**
 * acpiphp_check_bridge - re-enumerate devices
 *
 * Iterate over all slots under this bridge and make sure that if a
 * card is present they are enabled, and if not they are disabled.
 */
static int acpiphp_check_bridge(struct acpiphp_bridge *bridge)
{
        struct acpiphp_slot *slot;
        int retval = 0;
        int enabled, disabled;

        enabled = disabled = 0;

        for (slot = bridge->slots; slot; slot = slot->next) {
                unsigned int status = get_slot_status(slot);
                if (slot->flags & SLOT_ENABLED) {
                        if (status == ACPI_STA_ALL)
                                continue;
                        retval = acpiphp_disable_slot(slot);
                        if (retval) {
                                err("Error occurred in disabling\n");
                                goto err_exit;
                        } else {
                                acpiphp_eject_slot(slot);
                        }
                        disabled++;
                } else {
                        if (status != ACPI_STA_ALL)
                                continue;
                        retval = acpiphp_enable_slot(slot);
                        if (retval) {
                                err("Error occurred in enabling\n");
                                goto err_exit;
                        }
                        enabled++;
                }
        }

        dbg("%s: %d enabled, %d disabled\n", __FUNCTION__, enabled, disabled);

 err_exit:
        return retval;
}

static void program_hpp(struct pci_dev *dev, struct acpiphp_bridge *bridge)
{
        u16 pci_cmd, pci_bctl;
        struct pci_dev *cdev;

        /* Program hpp values for this device */
        if (!(dev->hdr_type == PCI_HEADER_TYPE_NORMAL ||
                        (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE &&
                        (dev->class >> 8) == PCI_CLASS_BRIDGE_PCI)))
                return;
        pci_write_config_byte(dev, PCI_CACHE_LINE_SIZE,
                        bridge->hpp.cache_line_size);
        pci_write_config_byte(dev, PCI_LATENCY_TIMER,
                        bridge->hpp.latency_timer);
        pci_read_config_word(dev, PCI_COMMAND, &pci_cmd);
        if (bridge->hpp.enable_serr)
                pci_cmd |= PCI_COMMAND_SERR;
        else
                pci_cmd &= ~PCI_COMMAND_SERR;
        if (bridge->hpp.enable_perr)
                pci_cmd |= PCI_COMMAND_PARITY;
        else
                pci_cmd &= ~PCI_COMMAND_PARITY;
        pci_write_config_word(dev, PCI_COMMAND, pci_cmd);

        /* Program bridge control value and child devices */
        if ((dev->class >> 8) == PCI_CLASS_BRIDGE_PCI) {
                pci_write_config_byte(dev, PCI_SEC_LATENCY_TIMER,
                                bridge->hpp.latency_timer);
                pci_read_config_word(dev, PCI_BRIDGE_CONTROL, &pci_bctl);
                if (bridge->hpp.enable_serr)
                        pci_bctl |= PCI_BRIDGE_CTL_SERR;
                else
                        pci_bctl &= ~PCI_BRIDGE_CTL_SERR;
                if (bridge->hpp.enable_perr)
                        pci_bctl |= PCI_BRIDGE_CTL_PARITY;
                else
                        pci_bctl &= ~PCI_BRIDGE_CTL_PARITY;
                pci_write_config_word(dev, PCI_BRIDGE_CONTROL, pci_bctl);
                if (dev->subordinate) {
                        list_for_each_entry(cdev, &dev->subordinate->devices,
                                        bus_list)
                                program_hpp(cdev, bridge);
                }
        }
}

static void acpiphp_set_hpp_values(acpi_handle handle, struct pci_bus *bus)
{
        struct acpiphp_bridge bridge;
        struct pci_dev *dev;

        memset(&bridge, 0, sizeof(bridge));
        bridge.handle = handle;
        bridge.pci_dev = bus->self;
        decode_hpp(&bridge);
        list_for_each_entry(dev, &bus->devices, bus_list)
                program_hpp(dev, &bridge);

}

/*
 * Remove devices for which we could not assign resources, call
 * arch specific code to fix-up the bus
 */
static void acpiphp_sanitize_bus(struct pci_bus *bus)
{
        struct pci_dev *dev;
        int i;
        unsigned long type_mask = IORESOURCE_IO | IORESOURCE_MEM;

        list_for_each_entry(dev, &bus->devices, bus_list) {
                for (i=0; i<PCI_BRIDGE_RESOURCES; i++) {
                        struct resource *res = &dev->resource[i];
                        if ((res->flags & type_mask) && !res->start &&
                                        res->end) {
                                /* Could not assign a required resources
                                 * for this device, remove it */
                                pci_remove_bus_device(dev);
                                break;
                        }
                }
        }
}

/* Program resources in newly inserted bridge */
static int acpiphp_configure_bridge (acpi_handle handle)
{
        struct acpi_pci_id pci_id;
        struct pci_bus *bus;

        if (ACPI_FAILURE(acpi_get_pci_id(handle, &pci_id))) {
                err("cannot get PCI domain and bus number for bridge\n");
                return -EINVAL;
        }
        bus = pci_find_bus(pci_id.segment, pci_id.bus);
        if (!bus) {
                err("cannot find bus %d:%d\n",
                                pci_id.segment, pci_id.bus);
                return -EINVAL;
        }

        pci_bus_size_bridges(bus);
        pci_bus_assign_resources(bus);
        acpiphp_sanitize_bus(bus);
        acpiphp_set_hpp_values(handle, bus);
        pci_enable_bridges(bus);
        acpiphp_configure_ioapics(handle);
        return 0;
}

static void handle_bridge_insertion(acpi_handle handle, u32 type)
{
        struct acpi_device *device, *pdevice;
        acpi_handle phandle;

        if ((type != ACPI_NOTIFY_BUS_CHECK) &&
                        (type != ACPI_NOTIFY_DEVICE_CHECK)) {
                err("unexpected notification type %d\n", type);
                return;
        }

        acpi_get_parent(handle, &phandle);
        if (acpi_bus_get_device(phandle, &pdevice)) {
                dbg("no parent device, assuming NULL\n");
                pdevice = NULL;
        }
        if (acpi_bus_add(&device, pdevice, handle, ACPI_BUS_TYPE_DEVICE)) {
                err("cannot add bridge to acpi list\n");
                return;
        }
        if (!acpiphp_configure_bridge(handle) &&
                !acpi_bus_start(device))
                add_bridge(handle);
        else
                err("cannot configure and start bridge\n");

}

/*
 * ACPI event handlers
 */

/**
 * handle_hotplug_event_bridge - handle ACPI event on bridges
 *
 * @handle: Notify()'ed acpi_handle
 * @type: Notify code
 * @context: pointer to acpiphp_bridge structure
 *
 * handles ACPI event notification on {host,p2p} bridges
 *
 */
static void handle_hotplug_event_bridge(acpi_handle handle, u32 type, void *context)
{
        struct acpiphp_bridge *bridge;
        char objname[64];
        struct acpi_buffer buffer = { .length = sizeof(objname),
                                      .pointer = objname };
        struct acpi_device *device;

        if (acpi_bus_get_device(handle, &device)) {
                /* This bridge must have just been physically inserted */
                handle_bridge_insertion(handle, type);
                return;
        }

        bridge = acpiphp_handle_to_bridge(handle);
        if (!bridge) {
                err("cannot get bridge info\n");
                return;
        }

        acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);

        switch (type) {
        case ACPI_NOTIFY_BUS_CHECK:
                /* bus re-enumerate */
                dbg("%s: Bus check notify on %s\n", __FUNCTION__, objname);
                acpiphp_check_bridge(bridge);
                break;

        case ACPI_NOTIFY_DEVICE_CHECK:
                /* device check */
                dbg("%s: Device check notify on %s\n", __FUNCTION__, objname);
                acpiphp_check_bridge(bridge);
                break;

        case ACPI_NOTIFY_DEVICE_WAKE:
                /* wake event */
                dbg("%s: Device wake notify on %s\n", __FUNCTION__, objname);
                break;

        case ACPI_NOTIFY_EJECT_REQUEST:
                /* request device eject */
                dbg("%s: Device eject notify on %s\n", __FUNCTION__, objname);
                break;

        case ACPI_NOTIFY_FREQUENCY_MISMATCH:
                printk(KERN_ERR "Device %s cannot be configured due"
                                " to a frequency mismatch\n", objname);
                break;

        case ACPI_NOTIFY_BUS_MODE_MISMATCH:
                printk(KERN_ERR "Device %s cannot be configured due"
                                " to a bus mode mismatch\n", objname);
                break;

        case ACPI_NOTIFY_POWER_FAULT:
                printk(KERN_ERR "Device %s has suffered a power fault\n",
                                objname);
                break;

        default:
                warn("notify_handler: unknown event type 0x%x for %s\n", type, objname);
                break;
        }
}

/**
 * handle_hotplug_event_func - handle ACPI event on functions (i.e. slots)
 *
 * @handle: Notify()'ed acpi_handle
 * @type: Notify code
 * @context: pointer to acpiphp_func structure
 *
 * handles ACPI event notification on slots
 *
 */
void handle_hotplug_event_func(acpi_handle handle, u32 type, void *context)
{
        struct acpiphp_func *func;
        char objname[64];
        struct acpi_buffer buffer = { .length = sizeof(objname),
                                      .pointer = objname };

        acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);

        func = (struct acpiphp_func *)context;

        switch (type) {
        case ACPI_NOTIFY_BUS_CHECK:
                /* bus re-enumerate */
                dbg("%s: Bus check notify on %s\n", __FUNCTION__, objname);
                acpiphp_enable_slot(func->slot);
                break;

        case ACPI_NOTIFY_DEVICE_CHECK:
                /* device check : re-enumerate from parent bus */
                dbg("%s: Device check notify on %s\n", __FUNCTION__, objname);
                acpiphp_check_bridge(func->slot->bridge);
                break;

        case ACPI_NOTIFY_DEVICE_WAKE:
                /* wake event */
                dbg("%s: Device wake notify on %s\n", __FUNCTION__, objname);
                break;

        case ACPI_NOTIFY_EJECT_REQUEST:
                /* request device eject */
                dbg("%s: Device eject notify on %s\n", __FUNCTION__, objname);
                if (!(acpiphp_disable_slot(func->slot)))
                        acpiphp_eject_slot(func->slot);
                break;

        default:
                warn("notify_handler: unknown event type 0x%x for %s\n", type, objname);
                break;
        }
}


static acpi_status
find_root_bridges(acpi_handle handle, u32 lvl, void *context, void **rv)
{
        int *count = (int *)context;

        if (acpi_root_bridge(handle)) {
                acpi_install_notify_handler(handle, ACPI_SYSTEM_NOTIFY,
                                handle_hotplug_event_bridge, NULL);
                        (*count)++;
        }
        return AE_OK ;
}

static struct acpi_pci_driver acpi_pci_hp_driver = {
        .add =          add_bridge,
        .remove =       remove_bridge,
};

/**
 * acpiphp_glue_init - initializes all PCI hotplug - ACPI glue data structures
 *
 */
int __init acpiphp_glue_init(void)
{
        int num = 0;

        acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
                        ACPI_UINT32_MAX, find_root_bridges, &num, NULL);

        if (num <= 0)
                return -1;
        else
                acpi_pci_register_driver(&acpi_pci_hp_driver);

        return 0;
}


/**
 * acpiphp_glue_exit - terminates all PCI hotplug - ACPI glue data structures
 *
 * This function frees all data allocated in acpiphp_glue_init()
 */
void __exit acpiphp_glue_exit(void)
{
        acpi_pci_unregister_driver(&acpi_pci_hp_driver);
}


/**
 * acpiphp_get_num_slots - count number of slots in a system
 */
int __init acpiphp_get_num_slots(void)
{
        struct list_head *node;
        struct acpiphp_bridge *bridge;
        int num_slots;

        num_slots = 0;

        list_for_each (node, &bridge_list) {
                bridge = (struct acpiphp_bridge *)node;
                dbg("Bus %04x:%02x has %d slot%s\n",
                                pci_domain_nr(bridge->pci_bus),
                                bridge->pci_bus->number, bridge->nr_slots,
                                bridge->nr_slots == 1 ? "" : "s");
                num_slots += bridge->nr_slots;
        }

        dbg("Total %d slots\n", num_slots);
        return num_slots;
}


#if 0
/**
 * acpiphp_for_each_slot - call function for each slot
 * @fn: callback function
 * @data: context to be passed to callback function
 *
 */
static int acpiphp_for_each_slot(acpiphp_callback fn, void *data)
{
        struct list_head *node;
        struct acpiphp_bridge *bridge;
        struct acpiphp_slot *slot;
        int retval = 0;

        list_for_each (node, &bridge_list) {
                bridge = (struct acpiphp_bridge *)node;
                for (slot = bridge->slots; slot; slot = slot->next) {
                        retval = fn(slot, data);
                        if (!retval)
                                goto err_exit;
                }
        }

 err_exit:
        return retval;
}
#endif


/**
 * acpiphp_enable_slot - power on slot
 */
int acpiphp_enable_slot(struct acpiphp_slot *slot)
{
        int retval;

        mutex_lock(&slot->crit_sect);

        /* wake up all functions */
        retval = power_on_slot(slot);
        if (retval)
                goto err_exit;

        if (get_slot_status(slot) == ACPI_STA_ALL)
                /* configure all functions */
                retval = enable_device(slot);

 err_exit:
        mutex_unlock(&slot->crit_sect);
        return retval;
}

/**
 * acpiphp_disable_slot - power off slot
 */
int acpiphp_disable_slot(struct acpiphp_slot *slot)
{
        int retval = 0;

        mutex_lock(&slot->crit_sect);

        /* unconfigure all functions */
        retval = disable_device(slot);
        if (retval)
                goto err_exit;

        /* power off all functions */
        retval = power_off_slot(slot);
        if (retval)
                goto err_exit;

 err_exit:
        mutex_unlock(&slot->crit_sect);
        return retval;
}


/*
 * slot enabled:  1
 * slot disabled: 0
 */
u8 acpiphp_get_power_status(struct acpiphp_slot *slot)
{
        return (slot->flags & SLOT_POWEREDON);
}


/*
 * latch closed:  1
 * latch   open:  0
 */
u8 acpiphp_get_latch_status(struct acpiphp_slot *slot)
{
        unsigned int sta;

        sta = get_slot_status(slot);

        return (sta & ACPI_STA_SHOW_IN_UI) ? 1 : 0;
}


/*
 * adapter presence : 1
 *          absence : 0
 */
u8 acpiphp_get_adapter_status(struct acpiphp_slot *slot)
{
        unsigned int sta;

        sta = get_slot_status(slot);

        return (sta == 0) ? 0 : 1;
}


/*
 * pci address (seg/bus/dev)
 */
u32 acpiphp_get_address(struct acpiphp_slot *slot)
{
        u32 address;
        struct pci_bus *pci_bus = slot->bridge->pci_bus;

        address = (pci_domain_nr(pci_bus) << 16) |
                  (pci_bus->number << 8) |
                  slot->device;

        return address;
}