/*
 *  pci_root.c - ACPI PCI Root Bridge Driver ($Revision: 41 $)
 *
 *  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")

extern struct pci_ops *pci_root_ops;

#define PREFIX                  "ACPI: "

static int acpi_pci_root_add (struct acpi_device *device);
static int acpi_pci_root_remove (struct acpi_device *device, int type);

static struct acpi_driver acpi_pci_root_driver = {
        .name =         ACPI_PCI_ROOT_DRIVER_NAME,
        .class =        ACPI_PCI_ROOT_CLASS,
        .ids =          ACPI_PCI_ROOT_HID,
        .ops =          {
                                .add =    acpi_pci_root_add,
                                .remove = acpi_pci_root_remove,
                        },
};

struct acpi_pci_root {
        struct list_head        node;
        acpi_handle             handle;
        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->handle);
                n++;
        }

        return n;
}

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)
                        continue;
                *pptr = (*pptr)->next;
                break;
        }

        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->handle);
        }
}

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

        if (resource->id != ACPI_RSTYPE_ADDRESS16 &&
            resource->id != ACPI_RSTYPE_ADDRESS32 &&
            resource->id != ACPI_RSTYPE_ADDRESS64)
                return AE_OK;

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

        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 int
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           value = 0;
        acpi_handle             handle = NULL;

        ACPI_FUNCTION_TRACE("acpi_pci_root_add");

        if (!device)
                return_VALUE(-EINVAL);

        root = kmalloc(sizeof(struct acpi_pci_root), GFP_KERNEL);
        if (!root)
                return_VALUE(-ENOMEM);
        memset(root, 0, sizeof(struct acpi_pci_root));

        root->handle = device->handle;
        sprintf(acpi_device_name(device), "%s", ACPI_PCI_ROOT_DEVICE_NAME);
        sprintf(acpi_device_class(device), "%s", ACPI_PCI_ROOT_CLASS);
        acpi_driver_data(device) = root;

        /*
         * TBD: Doesn't the bus driver automatically set this?
         */
        device->ops.bind = acpi_pci_bind;

        /* 
         * Segment
         * -------
         * Obtained via _SEG, if exists, otherwise assumed to be zero (0).
         */
        status = acpi_evaluate_integer(root->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_DEBUG_PRINT((ACPI_DB_ERROR, "Error evaluating _SEG\n"));
                result = -ENODEV;
                goto end;
        }

        /* 
         * Bus
         * ---
         * Obtained via _BBN, if exists, otherwise assumed to be zero (0).
         */
        status = acpi_evaluate_integer(root->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_DEBUG_PRINT((ACPI_DB_ERROR, "Error evaluating _BBN\n"));
                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;

                        ACPI_DEBUG_PRINT((ACPI_DB_ERROR, 
                                "Wrong _BBN value, please reboot and using option 'pci=noacpi'\n"));

                        status = try_get_root_bridge_busnr(root->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] (%02x:%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).
         */
#ifdef CONFIG_X86
        root->bus = pcibios_scan_root(root->id.bus);
#else
        root->bus = pcibios_scan_root(root->handle,
                                      root->id.segment, root->id.bus);
#endif
        if (!root->bus) {
                ACPI_DEBUG_PRINT((ACPI_DB_ERROR, 
                        "Bus %02x:%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(root->handle, METHOD_NAME__PRT, &handle);
        if (ACPI_SUCCESS(status))
                result = acpi_pci_irq_add_prt(root->handle, root->id.segment,
                        root->id.bus);

end:
        if (result)
                kfree(root);

        return_VALUE(result);
}


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

        ACPI_FUNCTION_TRACE("acpi_pci_root_remove");

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

        root = (struct acpi_pci_root *) acpi_driver_data(device);

        kfree(root);

        return_VALUE(0);
}


int __init
acpi_pci_root_init (void)
{
        ACPI_FUNCTION_TRACE("acpi_pci_root_init");

        /* DEBUG:
        acpi_dbg_layer = ACPI_PCI_COMPONENT;
        acpi_dbg_level = 0xFFFFFFFF;
         */

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

        return_VALUE(0);
}


void __exit
acpi_pci_root_exit (void)
{
        ACPI_FUNCTION_TRACE("acpi_pci_root_exit");

        acpi_bus_unregister_driver(&acpi_pci_root_driver);

        return_VOID;
}