acpiphp_glue.c

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/*
 * ACPI PCI HotPlug glue functions to ACPI CA subsystem
 *
 * Copyright (C) 2002,2003 Takayoshi Kochi ([email protected])
 * Copyright (C) 2002 Hiroshi Aono ([email protected])
 * Copyright (C) 2002,2003 NEC Corporation
 * Copyright (C) 2003-2005 Matthew Wilcox ([email protected])
 * Copyright (C) 2003-2005 Hewlett Packard
 * Copyright (C) 2005 Rajesh Shah ([email protected])
 * 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 <[email protected]>
 *
 */

/*
 * 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;
}



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;
}


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;
}


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);
    }
}

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;
}

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;
}


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;
}

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;
}

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 */
}

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 */
}

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,
};

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;
}


void  acpiphp_glue_exit(void)
{
    acpi_pci_unregister_driver(&acpi_pci_hp_driver);
}


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;
}


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;
}

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;
}