/*
 *  pci_root.c - ACPI PCI Root Bridge Driver ($Revision: 40 $)
 *
 *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
 *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 *
 *  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.  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.,
 *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/proc_fs.h>
#include <linux/spinlock.h>
#include <linux/pm.h>
#include <linux/pci.h>
#include <linux/acpi.h>
#include <acpi/acpi_bus.h>
#include <acpi/acpi_drivers.h>

#define _COMPONENT              ACPI_PCI_COMPONENT
ACPI_MODULE_NAME("pci_root");
#define ACPI_PCI_ROOT_CLASS             "pci_bridge"
#define ACPI_PCI_ROOT_DEVICE_NAME       "PCI Root Bridge"
static int acpi_pci_root_add(struct acpi_device *device);
static int acpi_pci_root_remove(struct acpi_device *device, int type);
static int acpi_pci_root_start(struct acpi_device *device);

static struct acpi_device_id root_device_ids[] = {
        {"PNP0A03", 0},
        {"", 0},
};
MODULE_DEVICE_TABLE(acpi, root_device_ids);

static struct acpi_driver acpi_pci_root_driver = {
        .name = "pci_root",
        .class = ACPI_PCI_ROOT_CLASS,
        .ids = root_device_ids,
        .ops = {
                .add = acpi_pci_root_add,
                .remove = acpi_pci_root_remove,
                .start = acpi_pci_root_start,
                },
};

struct acpi_pci_root {
        struct list_head node;
        struct acpi_device * device;
        struct acpi_pci_id id;
        struct pci_bus *bus;
};

static LIST_HEAD(acpi_pci_roots);

static struct acpi_pci_driver *sub_driver;

int acpi_pci_register_driver(struct acpi_pci_driver *driver)
{
        int n = 0;
        struct list_head *entry;

        struct acpi_pci_driver **pptr = &sub_driver;
        while (*pptr)
                pptr = &(*pptr)->next;
        *pptr = driver;

        if (!driver->add)
                return 0;

        list_for_each(entry, &acpi_pci_roots) {
                struct acpi_pci_root *root;
                root = list_entry(entry, struct acpi_pci_root, node);
                driver->add(root->device->handle);
                n++;
        }

        return n;
}

EXPORT_SYMBOL(acpi_pci_register_driver);

void acpi_pci_unregister_driver(struct acpi_pci_driver *driver)
{
        struct list_head *entry;

        struct acpi_pci_driver **pptr = &sub_driver;
        while (*pptr) {
                if (*pptr == driver)
                        break;
                pptr = &(*pptr)->next;
        }
        BUG_ON(!*pptr);
        *pptr = (*pptr)->next;

        if (!driver->remove)
                return;

        list_for_each(entry, &acpi_pci_roots) {
                struct acpi_pci_root *root;
                root = list_entry(entry, struct acpi_pci_root, node);
                driver->remove(root->device->handle);
        }
}

EXPORT_SYMBOL(acpi_pci_unregister_driver);

acpi_handle acpi_get_pci_rootbridge_handle(unsigned int seg, unsigned int bus)
{
        struct acpi_pci_root *tmp;
        
        list_for_each_entry(tmp, &acpi_pci_roots, node) {
                if ((tmp->id.segment == (u16) seg) && (tmp->id.bus == (u16) bus))
                        return tmp->device->handle;
        }
        return NULL;            
}

EXPORT_SYMBOL_GPL(acpi_get_pci_rootbridge_handle);

static acpi_status
get_root_bridge_busnr_callback(struct acpi_resource *resource, void *data)
{
        int *busnr = data;
        struct acpi_resource_address64 address;

        if (resource->type != ACPI_RESOURCE_TYPE_ADDRESS16 &&
            resource->type != ACPI_RESOURCE_TYPE_ADDRESS32 &&
            resource->type != ACPI_RESOURCE_TYPE_ADDRESS64)
                return AE_OK;

        acpi_resource_to_address64(resource, &address);
        if ((address.address_length > 0) &&
            (address.resource_type == ACPI_BUS_NUMBER_RANGE))
                *busnr = address.minimum;

        return AE_OK;
}

static acpi_status try_get_root_bridge_busnr(acpi_handle handle, int *busnum)
{
        acpi_status status;

        *busnum = -1;
        status =
            acpi_walk_resources(handle, METHOD_NAME__CRS,
                                get_root_bridge_busnr_callback, busnum);
        if (ACPI_FAILURE(status))
                return status;
        /* Check if we really get a bus number from _CRS */
        if (*busnum == -1)
                return AE_ERROR;
        return AE_OK;
}

static void acpi_pci_bridge_scan(struct acpi_device *device)
{
        int status;
        struct acpi_device *child = NULL;

        if (device->flags.bus_address)
                if (device->parent && device->parent->ops.bind) {
                        status = device->parent->ops.bind(device);
                        if (!status) {
                                list_for_each_entry(child, &device->children, node)
                                        acpi_pci_bridge_scan(child);
                        }
                }
}

static int __devinit acpi_pci_root_add(struct acpi_device *device)
{
        int result = 0;
        struct acpi_pci_root *root = NULL;
        struct acpi_pci_root *tmp;
        acpi_status status = AE_OK;
        unsigned long long value = 0;
        acpi_handle handle = NULL;
        struct acpi_device *child;


        if (!device)
                return -EINVAL;

        root = kzalloc(sizeof(struct acpi_pci_root), GFP_KERNEL);
        if (!root)
                return -ENOMEM;
        INIT_LIST_HEAD(&root->node);

        root->device = device;
        strcpy(acpi_device_name(device), ACPI_PCI_ROOT_DEVICE_NAME);
        strcpy(acpi_device_class(device), ACPI_PCI_ROOT_CLASS);
        device->driver_data = root;

        device->ops.bind = acpi_pci_bind;

        /* 
         * Segment
         * -------
         * Obtained via _SEG, if exists, otherwise assumed to be zero (0).
         */
        status = acpi_evaluate_integer(device->handle, METHOD_NAME__SEG, NULL,
                                       &value);
        switch (status) {
        case AE_OK:
                root->id.segment = (u16) value;
                break;
        case AE_NOT_FOUND:
                ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                                  "Assuming segment 0 (no _SEG)\n"));
                root->id.segment = 0;
                break;
        default:
                ACPI_EXCEPTION((AE_INFO, status, "Evaluating _SEG"));
                result = -ENODEV;
                goto end;
        }

        /* 
         * Bus
         * ---
         * Obtained via _BBN, if exists, otherwise assumed to be zero (0).
         */
        status = acpi_evaluate_integer(device->handle, METHOD_NAME__BBN, NULL,
                                       &value);
        switch (status) {
        case AE_OK:
                root->id.bus = (u16) value;
                break;
        case AE_NOT_FOUND:
                ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Assuming bus 0 (no _BBN)\n"));
                root->id.bus = 0;
                break;
        default:
                ACPI_EXCEPTION((AE_INFO, status, "Evaluating _BBN"));
                result = -ENODEV;
                goto end;
        }

        /* Some systems have wrong _BBN */
        list_for_each_entry(tmp, &acpi_pci_roots, node) {
                if ((tmp->id.segment == root->id.segment)
                    && (tmp->id.bus == root->id.bus)) {
                        int bus = 0;
                        acpi_status status;

                        printk(KERN_ERR PREFIX
                                    "Wrong _BBN value, reboot"
                                    " and use option 'pci=noacpi'\n");

                        status = try_get_root_bridge_busnr(device->handle, &bus);
                        if (ACPI_FAILURE(status))
                                break;
                        if (bus != root->id.bus) {
                                printk(KERN_INFO PREFIX
                                       "PCI _CRS %d overrides _BBN 0\n", bus);
                                root->id.bus = bus;
                        }
                        break;
                }
        }
        /*
         * Device & Function
         * -----------------
         * Obtained from _ADR (which has already been evaluated for us).
         */
        root->id.device = device->pnp.bus_address >> 16;
        root->id.function = device->pnp.bus_address & 0xFFFF;

        /*
         * TBD: Need PCI interface for enumeration/configuration of roots.
         */

        /* TBD: Locking */
        list_add_tail(&root->node, &acpi_pci_roots);

        printk(KERN_INFO PREFIX "%s [%s] (%04x:%02x)\n",
               acpi_device_name(device), acpi_device_bid(device),
               root->id.segment, root->id.bus);

        /*
         * Scan the Root Bridge
         * --------------------
         * Must do this prior to any attempt to bind the root device, as the
         * PCI namespace does not get created until this call is made (and 
         * thus the root bridge's pci_dev does not exist).
         */
        root->bus = pci_acpi_scan_root(device, root->id.segment, root->id.bus);
        if (!root->bus) {
                printk(KERN_ERR PREFIX
                            "Bus %04x:%02x not present in PCI namespace\n",
                            root->id.segment, root->id.bus);
                result = -ENODEV;
                goto end;
        }

        /*
         * Attach ACPI-PCI Context
         * -----------------------
         * Thus binding the ACPI and PCI devices.
         */
        result = acpi_pci_bind_root(device, &root->id, root->bus);
        if (result)
                goto end;

        /*
         * PCI Routing Table
         * -----------------
         * Evaluate and parse _PRT, if exists.
         */
        status = acpi_get_handle(device->handle, METHOD_NAME__PRT, &handle);
        if (ACPI_SUCCESS(status))
                result = acpi_pci_irq_add_prt(device->handle, root->id.segment,
                                              root->id.bus);

        /*
         * Scan and bind all _ADR-Based Devices
         */
        list_for_each_entry(child, &device->children, node)
                acpi_pci_bridge_scan(child);

      end:
        if (result) {
                if (!list_empty(&root->node))
                        list_del(&root->node);
                kfree(root);
        }

        return result;
}

static int acpi_pci_root_start(struct acpi_device *device)
{
        struct acpi_pci_root *root;


        list_for_each_entry(root, &acpi_pci_roots, node) {
                if (root->device == device) {
                        pci_bus_add_devices(root->bus);
                        return 0;
                }
        }
        return -ENODEV;
}

static int acpi_pci_root_remove(struct acpi_device *device, int type)
{
        struct acpi_pci_root *root = NULL;


        if (!device || !acpi_driver_data(device))
                return -EINVAL;

        root = acpi_driver_data(device);

        kfree(root);

        return 0;
}

static int __init acpi_pci_root_init(void)
{
        if (acpi_pci_disabled)
                return 0;

        if (acpi_bus_register_driver(&acpi_pci_root_driver) < 0)
                return -ENODEV;

        return 0;
}

subsys_initcall(acpi_pci_root_init);