/*
 * 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
 *
 * All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or (at
 * your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
 * NON INFRINGEMENT.  See the GNU General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 * Send feedback to <t-kochi@bq.jp.nec.com>
 *
 */

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

#include <linux/kernel.h>
#include <linux/pci.h>
#include <linux/smp_lock.h>
#include <asm/semaphore.h>

#include "pci_hotplug.h"
#include "acpiphp.h"

static LIST_HEAD(bridge_list);

#define MY_NAME "acpiphp_glue"

static void handle_hotplug_event_bridge (acpi_handle, u32, void *);
static void handle_hotplug_event_func (acpi_handle, u32, void *);

/*
 * initialization & terminatation routines
 */

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

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

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

        return 1;
}


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

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


/* callback routine to register each ACPI PCI slot object */
static acpi_status
register_slot (acpi_handle handle, u32 lvl, void *context, void **rv)
{
        struct acpiphp_bridge *bridge = (struct acpiphp_bridge *)context;
        struct acpiphp_slot *slot;
        struct acpiphp_func *newfunc;
        acpi_handle tmp;
        acpi_status status = AE_OK;
        unsigned long adr, sun;
        int device, function;
        static int num_slots = 0;       /* XXX if we support I/O node hotplug... */

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

        if (ACPI_FAILURE(status))
                return AE_OK;

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

        if (ACPI_FAILURE(status))
                return AE_OK;

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

        newfunc = kmalloc(sizeof(struct acpiphp_func), GFP_KERNEL);
        if (!newfunc)
                return AE_NO_MEMORY;
        memset(newfunc, 0, sizeof(struct acpiphp_func));

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

        status = acpi_evaluate_integer(handle, "_SUN", NULL, &sun);
        if (ACPI_FAILURE(status))
                sun = -1;

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

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

                memset(slot, 0, sizeof(struct acpiphp_slot));
                slot->bridge = bridge;
                slot->id = num_slots++;
                slot->device = device;
                slot->sun = sun;
                INIT_LIST_HEAD(&slot->funcs);
                init_MUTEX(&slot->crit_sect);

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

                bridge->nr_slots++;

                dbg("found ACPI PCI Hotplug slot at PCI %02x:%02x Slot:%d\n",
                    slot->bridge->bus, slot->device, slot->sun);
        }

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

        /* associate corresponding pci_dev */
        newfunc->pci_dev = pci_find_slot(bridge->bus,
                                         PCI_DEVFN(device, function));
        if (newfunc->pci_dev) {
                if (acpiphp_init_func_resource(newfunc) < 0) {
                        kfree(newfunc);
                        return AE_ERROR;
                }
                slot->flags |= (SLOT_ENABLED | SLOT_POWEREDON);
        }

        /* install notify handler */
        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");
                return status;
        }

        return AE_OK;
}


/* see if it's worth looking at this bridge */
static int detect_ejectable_slots (acpi_handle *bridge_handle)
{
        acpi_status status;
        int count;

        count = 0;

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

        return count;
}


/* decode ACPI _CRS data and convert into our internal resource list
 * TBD: _TRA, etc.
 */
static void
decode_acpi_resource (struct acpi_resource *resource, struct acpiphp_bridge *bridge)
{
        struct acpi_resource_address16 *address16_data;
        struct acpi_resource_address32 *address32_data;
        struct acpi_resource_address64 *address64_data;
        struct pci_resource *res;

        u32 resource_type, producer_consumer, address_length;
        u64 min_address_range, max_address_range;
        u16 cache_attribute = 0;

        int done = 0, found;

        /* shut up gcc */
        resource_type = producer_consumer = address_length = 0;
        min_address_range = max_address_range = 0;

        while (!done) {
                found = 0;

                switch (resource->id) {
                case ACPI_RSTYPE_ADDRESS16:
                        address16_data = (struct acpi_resource_address16 *)&resource->data;
                        resource_type = address16_data->resource_type;
                        producer_consumer = address16_data->producer_consumer;
                        min_address_range = address16_data->min_address_range;
                        max_address_range = address16_data->max_address_range;
                        address_length = address16_data->address_length;
                        if (resource_type == ACPI_MEMORY_RANGE)
                                cache_attribute = address16_data->attribute.memory.cache_attribute;
                        found = 1;
                        break;

                case ACPI_RSTYPE_ADDRESS32:
                        address32_data = (struct acpi_resource_address32 *)&resource->data;
                        resource_type = address32_data->resource_type;
                        producer_consumer = address32_data->producer_consumer;
                        min_address_range = address32_data->min_address_range;
                        max_address_range = address32_data->max_address_range;
                        address_length = address32_data->address_length;
                        if (resource_type == ACPI_MEMORY_RANGE)
                                cache_attribute = address32_data->attribute.memory.cache_attribute;
                        found = 1;
                        break;

                case ACPI_RSTYPE_ADDRESS64:
                        address64_data = (struct acpi_resource_address64 *)&resource->data;
                        resource_type = address64_data->resource_type;
                        producer_consumer = address64_data->producer_consumer;
                        min_address_range = address64_data->min_address_range;
                        max_address_range = address64_data->max_address_range;
                        address_length = address64_data->address_length;
                        if (resource_type == ACPI_MEMORY_RANGE)
                                cache_attribute = address64_data->attribute.memory.cache_attribute;
                        found = 1;
                        break;

                case ACPI_RSTYPE_END_TAG:
                        done = 1;
                        break;

                default:
                        /* ignore */
                        break;
                }

                resource = (struct acpi_resource *)((char*)resource + resource->length);

                if (found && producer_consumer == ACPI_PRODUCER && address_length > 0) {
                        switch (resource_type) {
                        case ACPI_MEMORY_RANGE:
                                if (cache_attribute == ACPI_PREFETCHABLE_MEMORY) {
                                        dbg("resource type: prefetchable memory 0x%x - 0x%x\n", (u32)min_address_range, (u32)max_address_range);
                                        res = acpiphp_make_resource(min_address_range,
                                                            address_length);
                                        if (!res) {
                                                err("out of memory\n");
                                                return;
                                        }
                                        res->next = bridge->p_mem_head;
                                        bridge->p_mem_head = res;
                                } else {
                                        dbg("resource type: memory 0x%x - 0x%x\n", (u32)min_address_range, (u32)max_address_range);
                                        res = acpiphp_make_resource(min_address_range,
                                                            address_length);
                                        if (!res) {
                                                err("out of memory\n");
                                                return;
                                        }
                                        res->next = bridge->mem_head;
                                        bridge->mem_head = res;
                                }
                                break;
                        case ACPI_IO_RANGE:
                                dbg("resource type: io 0x%x - 0x%x\n", (u32)min_address_range, (u32)max_address_range);
                                res = acpiphp_make_resource(min_address_range,
                                                    address_length);
                                if (!res) {
                                        err("out of memory\n");
                                        return;
                                }
                                res->next = bridge->io_head;
                                bridge->io_head = res;
                                break;
                        case ACPI_BUS_NUMBER_RANGE:
                                dbg("resource type: bus number %d - %d\n", (u32)min_address_range, (u32)max_address_range);
                                res = acpiphp_make_resource(min_address_range,
                                                    address_length);
                                if (!res) {
                                        err("out of memory\n");
                                        return;
                                }
                                res->next = bridge->bus_head;
                                bridge->bus_head = res;
                                break;
                        default:
                                /* invalid type */
                                break;
                        }
                }
        }

        acpiphp_resource_sort_and_combine(&bridge->io_head);
        acpiphp_resource_sort_and_combine(&bridge->mem_head);
        acpiphp_resource_sort_and_combine(&bridge->p_mem_head);
        acpiphp_resource_sort_and_combine(&bridge->bus_head);

        dbg("ACPI _CRS resource:\n");
        acpiphp_dump_resource(bridge);
}


/* find pci_bus structure associated to specific bus number */
static struct pci_bus *find_pci_bus(const struct list_head *list, int bus)
{
        const struct list_head *l;

        list_for_each (l, list) {
                struct pci_bus *b = pci_bus_b(l);
                if (b->number == bus)
                        return b;

                if (!list_empty(&b->children)) {
                        /* XXX recursive call */
                        b = find_pci_bus(&b->children, bus);

                        if (b)
                                return b;
                }
        }

        return NULL;
}


/* decode ACPI 2.0 _HPP hot plug parameters */
static void decode_hpp(struct acpiphp_bridge *bridge)
{
        acpi_status status;
        struct acpi_buffer buffer = { .length = ACPI_ALLOCATE_BUFFER,
                                      .pointer = NULL};
        union acpi_object *package;
        int i;

        /* default numbers */
        bridge->hpp.cache_line_size = 0x10;
        bridge->hpp.latency_timer = 0x40;
        bridge->hpp.enable_SERR = 0;
        bridge->hpp.enable_PERR = 0;

        status = acpi_evaluate_object(bridge->handle, "_HPP", NULL, &buffer);

        if (ACPI_FAILURE(status)) {
                dbg("_HPP evaluation failed\n");
                return;
        }

        package = (union acpi_object *) buffer.pointer;

        if (!package || package->type != ACPI_TYPE_PACKAGE ||
            package->package.count != 4 || !package->package.elements) {
                err("invalid _HPP object; ignoring\n");
                goto err_exit;
        }

        for (i = 0; i < 4; i++) {
                if (package->package.elements[i].type != ACPI_TYPE_INTEGER) {
                        err("invalid _HPP parameter type; ignoring\n");
                        goto err_exit;
                }
        }

        bridge->hpp.cache_line_size = package->package.elements[0].integer.value;
        bridge->hpp.latency_timer = package->package.elements[1].integer.value;
        bridge->hpp.enable_SERR = package->package.elements[2].integer.value;
        bridge->hpp.enable_PERR = package->package.elements[3].integer.value;

        dbg("_HPP parameter = (%02x, %02x, %02x, %02x)\n",
            bridge->hpp.cache_line_size,
            bridge->hpp.latency_timer,
            bridge->hpp.enable_SERR,
            bridge->hpp.enable_PERR);

        bridge->flags |= BRIDGE_HAS_HPP;

 err_exit:
        kfree(buffer.pointer);
}


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

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

        /* subtract all resources already allocated */
        acpiphp_detect_pci_resource(bridge);

        /* register all slot objects under this bridge */
        status = acpi_walk_namespace(ACPI_TYPE_DEVICE, bridge->handle, (u32)1,
                                     register_slot, bridge, NULL);

        /* install notify handler */
        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");
        }

        list_add(&bridge->list, &bridge_list);

        dbg("Bridge resource:\n");
        acpiphp_dump_resource(bridge);
}


/* allocate and initialize host bridge data structure */
static void add_host_bridge (acpi_handle *handle, int seg, int bus)
{
        acpi_status status;
        struct acpi_buffer buffer = { .length = ACPI_ALLOCATE_BUFFER,
                                      .pointer = NULL};
        struct acpiphp_bridge *bridge;

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

        memset(bridge, 0, sizeof(struct acpiphp_bridge));

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

        bridge->pci_bus = find_pci_bus(&pci_root_buses, bus);

        bridge->res_lock = SPIN_LOCK_UNLOCKED;

        /* to be overridden when we decode _CRS */
        bridge->sub = bridge->bus;

        /* decode resources */

        status = acpi_get_current_resources(handle, &buffer);

        if (ACPI_FAILURE(status)) {
                err("failed to decode bridge resources\n");
                kfree(bridge);
                return;
        }

        decode_acpi_resource(buffer.pointer, bridge);
        kfree(buffer.pointer);

        if (bridge->bus_head) {
                bridge->bus = bridge->bus_head->base;
                bridge->sub = bridge->bus_head->base + bridge->bus_head->length - 1;
        }

        init_bridge_misc(bridge);
}


/* allocate and initialize PCI-to-PCI bridge data structure */
static void add_p2p_bridge (acpi_handle *handle, int seg, int bus, int dev, int fn)
{
        struct acpiphp_bridge *bridge;
        u8 tmp8;
        u16 tmp16;
        u64 base64, limit64;
        u32 base, limit, base32u, limit32u;

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

        memset(bridge, 0, sizeof(struct acpiphp_bridge));

        bridge->type = BRIDGE_TYPE_P2P;
        bridge->handle = handle;
        bridge->seg = seg;

        bridge->pci_dev = pci_find_slot(bus, PCI_DEVFN(dev, fn));
        if (!bridge->pci_dev) {
                err("Can't get pci_dev\n");
                kfree(bridge);
                return;
        }

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

        bridge->res_lock = SPIN_LOCK_UNLOCKED;

        bridge->bus = bridge->pci_bus->number;
        bridge->sub = bridge->pci_bus->subordinate;

        /*
         * decode resources under this P2P bridge
         */

        /* I/O resources */
        pci_read_config_byte(bridge->pci_dev, PCI_IO_BASE, &tmp8);
        base = tmp8;
        pci_read_config_byte(bridge->pci_dev, PCI_IO_LIMIT, &tmp8);
        limit = tmp8;

        switch (base & PCI_IO_RANGE_TYPE_MASK) {
        case PCI_IO_RANGE_TYPE_16:
                base = (base << 8) & 0xf000;
                limit = ((limit << 8) & 0xf000) + 0xfff;
                bridge->io_head = acpiphp_make_resource((u64)base, limit - base + 1);
                if (!bridge->io_head) {
                        err("out of memory\n");
                        kfree(bridge);
                        return;
                }
                dbg("16bit I/O range: %04x-%04x\n",
                    (u32)bridge->io_head->base,
                    (u32)(bridge->io_head->base + bridge->io_head->length - 1));
                break;
        case PCI_IO_RANGE_TYPE_32:
                pci_read_config_word(bridge->pci_dev, PCI_IO_BASE_UPPER16, &tmp16);
                base = ((u32)tmp16 << 16) | ((base << 8) & 0xf000);
                pci_read_config_word(bridge->pci_dev, PCI_IO_LIMIT_UPPER16, &tmp16);
                limit = (((u32)tmp16 << 16) | ((limit << 8) & 0xf000)) + 0xfff;
                bridge->io_head = acpiphp_make_resource((u64)base, limit - base + 1);
                if (!bridge->io_head) {
                        err("out of memory\n");
                        kfree(bridge);
                        return;
                }
                dbg("32bit I/O range: %08x-%08x\n",
                    (u32)bridge->io_head->base,
                    (u32)(bridge->io_head->base + bridge->io_head->length - 1));
                break;
        case 0x0f:
                dbg("I/O space unsupported\n");
                break;
        default:
                warn("Unknown I/O range type\n");
        }

        /* Memory resources (mandatory for P2P bridge) */
        pci_read_config_word(bridge->pci_dev, PCI_MEMORY_BASE, &tmp16);
        base = (tmp16 & 0xfff0) << 16;
        pci_read_config_word(bridge->pci_dev, PCI_MEMORY_LIMIT, &tmp16);
        limit = ((tmp16 & 0xfff0) << 16) | 0xfffff;
        bridge->mem_head = acpiphp_make_resource((u64)base, limit - base + 1);
        if (!bridge->mem_head) {
                err("out of memory\n");
                kfree(bridge);
                return;
        }
        dbg("32bit Memory range: %08x-%08x\n",
            (u32)bridge->mem_head->base,
            (u32)(bridge->mem_head->base + bridge->mem_head->length-1));

        /* Prefetchable Memory resources (optional) */
        pci_read_config_word(bridge->pci_dev, PCI_PREF_MEMORY_BASE, &tmp16);
        base = tmp16;
        pci_read_config_word(bridge->pci_dev, PCI_PREF_MEMORY_LIMIT, &tmp16);
        limit = tmp16;

        switch (base & PCI_MEMORY_RANGE_TYPE_MASK) {
        case PCI_PREF_RANGE_TYPE_32:
                base = (base & 0xfff0) << 16;
                limit = ((limit & 0xfff0) << 16) | 0xfffff;
                bridge->p_mem_head = acpiphp_make_resource((u64)base, limit - base + 1);
                if (!bridge->p_mem_head) {
                        err("out of memory\n");
                        kfree(bridge);
                        return;
                }
                dbg("32bit Prefetchable memory range: %08x-%08x\n",
                    (u32)bridge->p_mem_head->base,
                    (u32)(bridge->p_mem_head->base + bridge->p_mem_head->length - 1));
                break;
        case PCI_PREF_RANGE_TYPE_64:
                pci_read_config_dword(bridge->pci_dev, PCI_PREF_BASE_UPPER32, &base32u);
                pci_read_config_dword(bridge->pci_dev, PCI_PREF_LIMIT_UPPER32, &limit32u);
                base64 = ((u64)base32u << 32) | ((base & 0xfff0) << 16);
                limit64 = (((u64)limit32u << 32) | ((limit & 0xfff0) << 16)) + 0xfffff;

                bridge->p_mem_head = acpiphp_make_resource(base64, limit64 - base64 + 1);
                if (!bridge->p_mem_head) {
                        err("out of memory\n");
                        kfree(bridge);
                        return;
                }
                dbg("64bit Prefetchable memory range: %08x%08x-%08x%08x\n",
                    (u32)(bridge->p_mem_head->base >> 32),
                    (u32)(bridge->p_mem_head->base & 0xffffffff),
                    (u32)((bridge->p_mem_head->base + bridge->p_mem_head->length - 1) >> 32),
                    (u32)((bridge->p_mem_head->base + bridge->p_mem_head->length - 1) & 0xffffffff));
                break;
        case 0x0f:
                break;
        default:
                warn("Unknown prefetchale memory type\n");
        }

        init_bridge_misc(bridge);
}


/* callback routine to find P2P bridges */
static acpi_status
find_p2p_bridge (acpi_handle handle, u32 lvl, void *context, void **rv)
{
        acpi_status status;
        acpi_handle dummy_handle;
        unsigned long *segbus = context;
        unsigned long tmp;
        int seg, bus, device, function;
        struct pci_dev *dev;

        /* get PCI address */
        seg = (*segbus >> 8) & 0xff;
        bus = *segbus & 0xff;

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

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

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

        dev = pci_find_slot(bus, PCI_DEVFN(device, function));

        if (!dev)
                return AE_OK;

        if (!dev->subordinate)
                return AE_OK;

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

        return AE_OK;
}


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

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

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

        seg = ACPI_SUCCESS(status) ? tmp : 0;

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

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

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

        tmp = seg << 8 | bus;

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

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

        return 0;
}


static void remove_bridge (acpi_handle handle)
{
        /* No-op for now .. */
}

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

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

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

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

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

        slot->flags |= SLOT_POWEREDON;

 err_exit:
        return retval;
}


static int power_off_slot (struct acpiphp_slot *slot)
{
        acpi_status status;
        struct acpiphp_func *func;
        struct list_head *l;
        struct acpi_object_list arg_list;
        union acpi_object arg;

        int retval = 0;

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

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

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

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

                /* We don't want to call _EJ0 on non-existing functions. */
                if (func->pci_dev && (func->flags & FUNC_HAS_EJ0)) {
                        /* _EJ0 method take one argument */
                        arg_list.count = 1;
                        arg_list.pointer = &arg;
                        arg.type = ACPI_TYPE_INTEGER;
                        arg.integer.value = 1;
                        status = acpi_evaluate_object(func->handle, "_EJ0", &arg_list, NULL);
                        if (ACPI_FAILURE(status)) {
                                warn("%s: _EJ0 failed\n", __FUNCTION__);
                                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;
}


/**
 * enable_device - enable, configure a slot
 * @slot: slot to be enabled
 *
 * This function should be called per *physical slot*,
 * not per each slot object in ACPI namespace.
 *
 */
static int enable_device (struct acpiphp_slot *slot)
{
        u8 bus;
        struct pci_dev dev0, *dev;
        struct pci_bus *child;
        struct list_head *l;
        struct acpiphp_func *func;
        int retval = 0;

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

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

        /* allocate resources to device */
        retval = acpiphp_configure_slot(slot);
        if (retval)
                goto err_exit;

        memset(&dev0, 0, sizeof (struct pci_dev));

        dev0.bus = slot->bridge->pci_bus;
        dev0.devfn = PCI_DEVFN(slot->device, 0);
        dev0.sysdata = dev0.bus->sysdata;

        /* returned `dev' is the *first function* only! */
        dev = pci_scan_slot (&dev0);

        if (!dev) {
                err("No new device found\n");
                retval = -1;
                goto err_exit;
        }

        if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE) {
                pci_read_config_byte(dev, PCI_SECONDARY_BUS, &bus);
                child = (struct pci_bus*) pci_add_new_bus(dev->bus, dev, bus);
                pci_do_scan_bus(child);
        }

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

                func->pci_dev = pci_find_slot(slot->bridge->bus,
                                              PCI_DEVFN(slot->device,
                                                        func->function));
                if (!func->pci_dev)
                        continue;

                /* configure device */
                retval = acpiphp_configure_function(func);
                if (retval)
                        goto err_exit;
        }

        slot->flags |= SLOT_ENABLED;

        dbg("Available resources:\n");
        acpiphp_dump_resource(slot->bridge);

 err_exit:
        return retval;
}


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

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

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

                if (func->pci_dev)
                        if (acpiphp_unconfigure_function(func)) {
                                err("failed to unconfigure device\n");
                                retval = -1;
                                goto err_exit;
                        }
        }

        slot->flags &= (~SLOT_ENABLED);

 err_exit:
        return retval;
}


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

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

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

        return (unsigned int)sta;
}


/*
 * ACPI event handlers
 */

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

        bridge = (struct acpiphp_bridge *)context;

        acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);

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

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

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

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

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


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

        acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);

        func = (struct acpiphp_func *)context;

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

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

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

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

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


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 acpiphp_glue_init (void)
{
        int num;

        if (list_empty(&pci_root_buses))
                return -1;

        num = acpi_pci_register_driver(&acpi_pci_hp_driver);

        if (num <= 0)
                return -1;

        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)
{
        struct list_head *l1, *l2, *n1, *n2;
        struct acpiphp_bridge *bridge;
        struct acpiphp_slot *slot, *next;
        struct acpiphp_func *func;
        acpi_status status;

        list_for_each_safe (l1, n1, &bridge_list) {
                bridge = (struct acpiphp_bridge *)l1;
                slot = bridge->slots;
                while (slot) {
                        next = slot->next;
                        list_for_each_safe (l2, n2, &slot->funcs) {
                                func = list_entry(l2, struct acpiphp_func, sibling);
                                acpiphp_free_resource(&func->io_head);
                                acpiphp_free_resource(&func->mem_head);
                                acpiphp_free_resource(&func->p_mem_head);
                                acpiphp_free_resource(&func->bus_head);
                                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");
                                kfree(func);
                        }
                        kfree(slot);
                        slot = next;
                }
                status = acpi_remove_notify_handler(bridge->handle, ACPI_SYSTEM_NOTIFY,
                                                    handle_hotplug_event_bridge);
                if (ACPI_FAILURE(status))
                        err("failed to remove notify handler\n");

                acpiphp_free_resource(&bridge->io_head);
                acpiphp_free_resource(&bridge->mem_head);
                acpiphp_free_resource(&bridge->p_mem_head);
                acpiphp_free_resource(&bridge->bus_head);

                kfree(bridge);
        }
}


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

        num_slots = 0;

        list_for_each (node, &bridge_list) {
                bridge = (struct acpiphp_bridge *)node;
                dbg("Bus%d %dslot(s)\n", bridge->bus, bridge->nr_slots);
                num_slots += bridge->nr_slots;
        }

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


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

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

 err_exit:
        return retval;
}


/* search matching slot from id  */
struct acpiphp_slot *get_slot_from_id (int id)
{
        struct list_head *node;
        struct acpiphp_bridge *bridge;
        struct acpiphp_slot *slot;

        list_for_each (node, &bridge_list) {
                bridge = (struct acpiphp_bridge *)node;
                for (slot = bridge->slots; slot; slot = slot->next)
                        if (slot->id == id)
                                return slot;
        }

        /* should never happen! */
        err("%s: no object for id %d\n",__FUNCTION__, id);
        return 0;
}


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

        down(&slot->crit_sect);

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

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

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


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

        down(&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;

        acpiphp_resource_sort_and_combine(&slot->bridge->io_head);
        acpiphp_resource_sort_and_combine(&slot->bridge->mem_head);
        acpiphp_resource_sort_and_combine(&slot->bridge->p_mem_head);
        acpiphp_resource_sort_and_combine(&slot->bridge->bus_head);
        dbg("Available resources:\n");
        acpiphp_dump_resource(slot->bridge);

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


/**
 * acpiphp_check_bridge - re-enumerate devices
 */
int acpiphp_check_bridge (struct acpiphp_bridge *bridge)
{
        struct acpiphp_slot *slot;
        unsigned int sta;
        int retval = 0;
        int enabled, disabled;

        enabled = disabled = 0;

        for (slot = bridge->slots; slot; slot = slot->next) {
                sta = get_slot_status(slot);
                if (slot->flags & SLOT_ENABLED) {
                        /* if enabled but not present, disable */
                        if (sta != ACPI_STA_ALL) {
                                retval = acpiphp_disable_slot(slot);
                                if (retval) {
                                        err("Error occurred in enabling\n");
                                        up(&slot->crit_sect);
                                        goto err_exit;
                                }
                                disabled++;
                        }
                } else {
                        /* if disabled but present, enable */
                        if (sta == ACPI_STA_ALL) {
                                retval = acpiphp_enable_slot(slot);
                                if (retval) {
                                        err("Error occurred in enabling\n");
                                        up(&slot->crit_sect);
                                        goto err_exit;
                                }
                                enabled++;
                        }
                }
        }

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

 err_exit:
        return retval;
}


/*
 * slot enabled:  1
 * slot disabled: 0
 */
u8 acpiphp_get_power_status (struct acpiphp_slot *slot)
{
        unsigned int sta;

        sta = get_slot_status(slot);

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


/*
 * attention LED ON: 1
 *              OFF: 0
 *
 * TBD
 * no direct attention led status information via ACPI
 *
 */
u8 acpiphp_get_attention_status (struct acpiphp_slot *slot)
{
        return 0;
}


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

        sta = get_slot_status(slot);

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


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

        sta = get_slot_status(slot);

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


/*
 * pci address (seg/bus/dev)
 */
u32 acpiphp_get_address (struct acpiphp_slot *slot)
{
        u32 address;

        address = ((slot->bridge->seg) << 16) |
                  ((slot->bridge->bus) << 8) |
                  slot->device;

        return address;
}