/*
 * 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 <linux/slab.h>
#include <linux/acpi.h>

#include "../pci.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(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->busn_res.start) {
                buses = (buses & 0xff000000)
                        | ((unsigned int)(bus->primary)     <<  0)
                        | ((unsigned int)(bus->busn_res.start)   <<  8)
                        | ((unsigned int)(bus->busn_res.end) << 16);
                pci_write_config_dword(bus->self, PCI_PRIMARY_BUS, buses);
        }
        return NOTIFY_OK;
}


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

/* Check whether the PCI device is managed by native PCIe hotplug driver */
static bool device_is_managed_by_native_pciehp(struct pci_dev *pdev)
{
        u32 reg32;
        acpi_handle tmp;
        struct acpi_pci_root *root;

        /* Check whether the PCIe port supports native PCIe hotplug */
        if (pcie_capability_read_dword(pdev, PCI_EXP_SLTCAP, &reg32))
                return false;
        if (!(reg32 & PCI_EXP_SLTCAP_HPC))
                return false;

        /*
         * Check whether native PCIe hotplug has been enabled for
         * this PCIe hierarchy.
         */
        tmp = acpi_find_root_bridge_handle(pdev);
        if (!tmp)
                return false;
        root = acpi_pci_find_root(tmp);
        if (!root)
                return false;
        if (!(root->osc_control_set & OSC_PCI_EXPRESS_NATIVE_HP_CONTROL))
                return false;

        return true;
}

/* 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;

        status = acpi_evaluate_integer(handle, "_ADR", NULL, &adr);
        if (ACPI_FAILURE(status)) {
                warn("can't evaluate _ADR (%#x)\n", status);
                return AE_OK;
        }

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

        pdev = pbus->self;
        if (pdev && device_is_managed_by_native_pciehp(pdev))
                return AE_OK;

        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, NULL, (void *)&found, NULL);
        }
        return found;
}

/* 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, NULL, 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 acpiphp_bridge *bridge;
        struct acpiphp_slot *slot;
        struct acpiphp_func *func;

        list_for_each_entry(bridge, &bridge_list, list) {
                for (slot = bridge->slots; slot; slot = slot->next) {
                        list_for_each_entry(func, &slot->funcs, 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(struct acpi_pci_root *root)
{
        struct acpiphp_bridge *bridge;
        acpi_handle handle = root->device->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;

        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);

        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, 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(struct acpi_pci_root *root)
{
        acpi_status status;
        unsigned long long tmp;
        acpi_handle dummy_handle;
        acpi_handle handle = root->device->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(root);
        }

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

        list_for_each_entry(bridge, &bridge_list, list)
                if (bridge->handle == handle)
                        return bridge;

        return NULL;
}

static void cleanup_bridge(struct acpiphp_bridge *bridge)
{
        struct acpiphp_slot *slot, *next;
        struct acpiphp_func *func, *tmp;
        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) {
                next = slot->next;
                list_for_each_entry_safe(func, tmp, &slot->funcs, 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(&func->sibling);
                        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, NULL);

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

        return AE_OK;
}

static void remove_bridge(struct acpi_pci_root *root)
{
        struct acpiphp_bridge *bridge;
        acpi_handle handle = root->device->handle;

        /* 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, NULL);

        /*
         * On root bridges with hotplug slots directly underneath (ie,
         * no p2p bridge between), 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 int power_on_slot(struct acpiphp_slot *slot)
{
        acpi_status status;
        struct acpiphp_func *func;
        int retval = 0;

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

        list_for_each_entry(func, &slot->funcs, 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;

        int retval = 0;

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

        list_for_each_entry(func, &slot->funcs, 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->busn_res.start;

        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;
        }
        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;
}

static void acpiphp_set_acpi_region(struct acpiphp_slot *slot)
{
        struct acpiphp_func *func;
        union acpi_object params[2];
        struct acpi_object_list arg_list;

        list_for_each_entry(func, &slot->funcs, sibling) {
                arg_list.count = 2;
                arg_list.pointer = params;
                params[0].type = ACPI_TYPE_INTEGER;
                params[0].integer.value = ACPI_ADR_SPACE_PCI_CONFIG;
                params[1].type = ACPI_TYPE_INTEGER;
                params[1].integer.value = 1;
                /* _REG is optional, we don't care about if there is failure */
                acpi_evaluate_object(func->handle, "_REG", &arg_list, NULL);
        }
}

/**
 * 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 acpiphp_func *func;
        int retval = 0;
        int num, max, pass;
        acpi_status status;

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

        num = pci_scan_slot(bus, PCI_DEVFN(slot->device, 0));
        if (num == 0) {
                /* Maybe only part of funcs are added. */
                dbg("No new device found\n");
                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);
                        }
                }
        }

        list_for_each_entry(func, &slot->funcs, sibling)
                acpiphp_bus_add(func);

        pci_bus_assign_resources(bus);
        acpiphp_sanitize_bus(bus);
        acpiphp_set_hpp_values(bus);
        acpiphp_set_acpi_region(slot);
        pci_enable_bridges(bus);

        list_for_each_entry(dev, &bus->devices, bus_list) {
                /* Assume that newly added devices are powered on already. */
                if (!dev->is_added)
                        dev->current_state = PCI_D0;
        }

        pci_bus_add_devices(bus);

        slot->flags |= SLOT_ENABLED;
        list_for_each_entry(func, &slot->funcs, sibling) {
                dev = pci_get_slot(bus, PCI_DEVFN(slot->device,
                                                  func->function));
                if (!dev) {
                        /* Do not set SLOT_ENABLED flag if some funcs
                           are not added. */
                        slot->flags &= (~SLOT_ENABLED);
                        continue;
                }

                if (dev->hdr_type != PCI_HEADER_TYPE_BRIDGE &&
                    dev->hdr_type != PCI_HEADER_TYPE_CARDBUS) {
                        pci_dev_put(dev);
                        continue;
                }

                status = find_p2p_bridge(func->handle, (u32)1, bus, NULL);
                if (ACPI_FAILURE(status))
                        warn("find_p2p_bridge failed (error code = 0x%x)\n",
                                status);
                pci_dev_put(dev);
        }


 err_exit:
        return retval;
}

/* return first device in slot, acquiring a reference on it */
static struct pci_dev *dev_in_slot(struct acpiphp_slot *slot)
{
        struct pci_bus *bus = slot->bridge->pci_bus;
        struct pci_dev *dev;
        struct pci_dev *ret = NULL;

        down_read(&pci_bus_sem);
        list_for_each_entry(dev, &bus->devices, bus_list)
                if (PCI_SLOT(dev->devfn) == slot->device) {
                        ret = pci_dev_get(dev);
                        break;
                }
        up_read(&pci_bus_sem);

        return ret;
}

/**
 * disable_device - disable a slot
 * @slot: ACPI PHP slot
 */
static int disable_device(struct acpiphp_slot *slot)
{
        struct acpiphp_func *func;
        struct pci_dev *pdev;
        struct pci_bus *bus = slot->bridge->pci_bus;

        /* The slot will be enabled when func 0 is added, so check
           func 0 before disable the slot. */
        pdev = pci_get_slot(bus, PCI_DEVFN(slot->device, 0));
        if (!pdev)
                goto err_exit;
        pci_dev_put(pdev);

        list_for_each_entry(func, &slot->funcs, sibling) {
                if (func->bridge) {
                        /* cleanup p2p bridges under this P2P bridge */
                        cleanup_p2p_bridge(func->bridge->handle,
                                                (u32)1, NULL, NULL);
                        func->bridge = NULL;
                }
        }

        /*
         * enable_device() enumerates all functions in this device via
         * pci_scan_slot(), whether they have associated ACPI hotplug
         * methods (_EJ0, etc.) or not.  Therefore, we remove all functions
         * here.
         */
        while ((pdev = dev_in_slot(slot))) {
                pci_stop_and_remove_bus_device(pdev);
                pci_dev_put(pdev);
        }

        list_for_each_entry(func, &slot->funcs, sibling) {
                acpiphp_bus_trim(func->handle);
        }

        slot->flags &= (~SLOT_ENABLED);

err_exit:
        return 0;
}


/**
 * get_slot_status - get ACPI slot status
 * @slot: ACPI PHP slot
 *
 * 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 long sta = 0;
        u32 dvid;
        struct acpiphp_func *func;

        list_for_each_entry(func, &slot->funcs, 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
 * @slot: ACPI PHP slot
 */
int acpiphp_eject_slot(struct acpiphp_slot *slot)
{
        acpi_status status;
        struct acpiphp_func *func;
        struct acpi_object_list arg_list;
        union acpi_object arg;

        list_for_each_entry(func, &slot->funcs, 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", __func__);
                                return -1;
                        } else
                                break;
                }
        }
        return 0;
}

/**
 * acpiphp_check_bridge - re-enumerate devices
 * @bridge: where to begin re-enumeration
 *
 * 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", __func__, enabled, disabled);

 err_exit:
        return retval;
}

static void acpiphp_set_hpp_values(struct pci_bus *bus)
{
        struct pci_dev *dev;

        list_for_each_entry(dev, &bus->devices, bus_list)
                pci_configure_slot(dev);
}

/*
 * 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_stop_and_remove_bus_device(dev);
                                break;
                        }
                }
        }
}

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

        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_bus_size_bridges(bus);
        pci_bus_assign_resources(bus);
        acpiphp_sanitize_bus(bus);
        acpiphp_set_hpp_values(bus);
        pci_enable_bridges(bus);
        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
 */

static acpi_status
count_sub_bridges(acpi_handle handle, u32 lvl, void *context, void **rv)
{
        int *count = (int *)context;
        struct acpiphp_bridge *bridge;

        bridge = acpiphp_handle_to_bridge(handle);
        if (bridge)
                (*count)++;
        return AE_OK ;
}

static acpi_status
check_sub_bridges(acpi_handle handle, u32 lvl, void *context, void **rv)
{
        struct acpiphp_bridge *bridge;
        char objname[64];
        struct acpi_buffer buffer = { .length = sizeof(objname),
                                      .pointer = objname };

        bridge = acpiphp_handle_to_bridge(handle);
        if (bridge) {
                acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
                dbg("%s: re-enumerating slots under %s\n",
                        __func__, objname);
                acpiphp_check_bridge(bridge);
        }
        return AE_OK ;
}

struct acpiphp_hp_work {
        struct work_struct work;
        acpi_handle handle;
        u32 type;
        void *context;
};

static void alloc_acpiphp_hp_work(acpi_handle handle, u32 type,
                                  void *context,
                                  void (*func)(struct work_struct *work))
{
        struct acpiphp_hp_work *hp_work;
        int ret;

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

        hp_work->handle = handle;
        hp_work->type = type;
        hp_work->context = context;

        INIT_WORK(&hp_work->work, func);
        ret = queue_work(kacpi_hotplug_wq, &hp_work->work);
        if (!ret)
                kfree(hp_work);
}

static void _handle_hotplug_event_bridge(struct work_struct *work)
{
        struct acpiphp_bridge *bridge;
        char objname[64];
        struct acpi_buffer buffer = { .length = sizeof(objname),
                                      .pointer = objname };
        struct acpi_device *device;
        int num_sub_bridges = 0;
        struct acpiphp_hp_work *hp_work;
        acpi_handle handle;
        u32 type;

        hp_work = container_of(work, struct acpiphp_hp_work, work);
        handle = hp_work->handle;
        type = hp_work->type;

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

        bridge = acpiphp_handle_to_bridge(handle);
        if (type == ACPI_NOTIFY_BUS_CHECK) {
                acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, ACPI_UINT32_MAX,
                        count_sub_bridges, NULL, &num_sub_bridges, NULL);
        }

        if (!bridge && !num_sub_bridges) {
                err("cannot get bridge info\n");
                goto out;
        }

        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", __func__, objname);
                if (bridge) {
                        dbg("%s: re-enumerating slots under %s\n",
                                __func__, objname);
                        acpiphp_check_bridge(bridge);
                }
                if (num_sub_bridges)
                        acpi_walk_namespace(ACPI_TYPE_DEVICE, handle,
                                ACPI_UINT32_MAX, check_sub_bridges, NULL, NULL, NULL);
                break;

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

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

        case ACPI_NOTIFY_EJECT_REQUEST:
                /* request device eject */
                dbg("%s: Device eject notify on %s\n", __func__, objname);
                if ((bridge->type != BRIDGE_TYPE_HOST) &&
                    (bridge->flags & BRIDGE_HAS_EJ0)) {
                        struct acpiphp_slot *slot;
                        slot = bridge->func->slot;
                        if (!acpiphp_disable_slot(slot))
                                acpiphp_eject_slot(slot);
                }
                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;
        }

out:
        kfree(hp_work); /* allocated in handle_hotplug_event_bridge */
}

/**
 * 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)
{
        /*
         * Currently the code adds all hotplug events to the kacpid_wq
         * queue when it should add hotplug events to the kacpi_hotplug_wq.
         * The proper way to fix this is to reorganize the code so that
         * drivers (dock, etc.) do not call acpi_os_execute(), etc.
         * For now just re-add this work to the kacpi_hotplug_wq so we
         * don't deadlock on hotplug actions.
         */
        alloc_acpiphp_hp_work(handle, type, context,
                              _handle_hotplug_event_bridge);
}

static void _handle_hotplug_event_func(struct work_struct *work)
{
        struct acpiphp_func *func;
        char objname[64];
        struct acpi_buffer buffer = { .length = sizeof(objname),
                                      .pointer = objname };
        struct acpiphp_hp_work *hp_work;
        acpi_handle handle;
        u32 type;
        void *context;

        hp_work = container_of(work, struct acpiphp_hp_work, work);
        handle = hp_work->handle;
        type = hp_work->type;
        context = hp_work->context;

        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", __func__, 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", __func__, objname);
                acpiphp_check_bridge(func->slot->bridge);
                break;

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

        case ACPI_NOTIFY_EJECT_REQUEST:
                /* request device eject */
                dbg("%s: Device eject notify on %s\n", __func__, 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;
        }

        kfree(hp_work); /* allocated in handle_hotplug_event_func */
}

/**
 * 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.
 */
static void handle_hotplug_event_func(acpi_handle handle, u32 type,
                                      void *context)
{
        /*
         * Currently the code adds all hotplug events to the kacpid_wq
         * queue when it should add hotplug events to the kacpi_hotplug_wq.
         * The proper way to fix this is to reorganize the code so that
         * drivers (dock, etc.) do not call acpi_os_execute(), etc.
         * For now just re-add this work to the kacpi_hotplug_wq so we
         * don't deadlock on hotplug actions.
         */
        alloc_acpiphp_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,
};

/**
 * 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, NULL, &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  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 acpiphp_bridge *bridge;
        int num_slots = 0;

        list_for_each_entry(bridge, &bridge_list, list) {
                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;
}


/**
 * acpiphp_enable_slot - power on slot
 * @slot: ACPI PHP 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);
                if (retval)
                        power_off_slot(slot);
        } else {
                dbg("%s: Slot status is not ACPI_STA_ALL\n", __func__);
                power_off_slot(slot);
        }

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

/**
 * acpiphp_disable_slot - power off slot
 * @slot: ACPI PHP 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   open:  1
 * latch closed:  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) ? 0 : 1;
}


/*
 * 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;
}