/*
 * AGPGART driver frontend
 * Copyright (C) 2004 Silicon Graphics, Inc.
 * Copyright (C) 2002-2003 Dave Jones
 * Copyright (C) 1999 Jeff Hartmann
 * Copyright (C) 1999 Precision Insight, Inc.
 * Copyright (C) 1999 Xi Graphics, Inc.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * JEFF HARTMANN, OR ANY OTHER CONTRIBUTORS BE LIABLE FOR ANY CLAIM,
 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE
 * OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
 */

#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mman.h>
#include <linux/pci.h>
#include <linux/init.h>
#include <linux/miscdevice.h>
#include <linux/agp_backend.h>
#include <linux/agpgart.h>
#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/fs.h>
#include <linux/sched.h>
#include <asm/uaccess.h>
#include <asm/pgtable.h>
#include "agp.h"

struct agp_front_data agp_fe;

struct agp_memory *agp_find_mem_by_key(int key)
{
        struct agp_memory *curr;

        if (agp_fe.current_controller == NULL)
                return NULL;

        curr = agp_fe.current_controller->pool;

        while (curr != NULL) {
                if (curr->key == key)
                        break;
                curr = curr->next;
        }

        DBG("key=%d -> mem=%p", key, curr);
        return curr;
}

static void agp_remove_from_pool(struct agp_memory *temp)
{
        struct agp_memory *prev;
        struct agp_memory *next;

        /* Check to see if this is even in the memory pool */

        DBG("mem=%p", temp);
        if (agp_find_mem_by_key(temp->key) != NULL) {
                next = temp->next;
                prev = temp->prev;

                if (prev != NULL) {
                        prev->next = next;
                        if (next != NULL)
                                next->prev = prev;

                } else {
                        /* This is the first item on the list */
                        if (next != NULL)
                                next->prev = NULL;

                        agp_fe.current_controller->pool = next;
                }
        }
}

/*
 * Routines for managing each client's segment list -
 * These routines handle adding and removing segments
 * to each auth'ed client.
 */

static struct
agp_segment_priv *agp_find_seg_in_client(const struct agp_client *client,
                                                unsigned long offset,
                                            int size, pgprot_t page_prot)
{
        struct agp_segment_priv *seg;
        int num_segments, i;
        off_t pg_start;
        size_t pg_count;

        pg_start = offset / 4096;
        pg_count = size / 4096;
        seg = *(client->segments);
        num_segments = client->num_segments;

        for (i = 0; i < client->num_segments; i++) {
                if ((seg[i].pg_start == pg_start) &&
                    (seg[i].pg_count == pg_count) &&
                    (pgprot_val(seg[i].prot) == pgprot_val(page_prot))) {
                        return seg + i;
                }
        }

        return NULL;
}

static void agp_remove_seg_from_client(struct agp_client *client)
{
        DBG("client=%p", client);

        if (client->segments != NULL) {
                if (*(client->segments) != NULL) {
                        DBG("Freeing %p from client %p", *(client->segments), client);
                        kfree(*(client->segments));
                }
                DBG("Freeing %p from client %p", client->segments, client);
                kfree(client->segments);
                client->segments = NULL;
        }
}

static void agp_add_seg_to_client(struct agp_client *client,
                               struct agp_segment_priv ** seg, int num_segments)
{
        struct agp_segment_priv **prev_seg;

        prev_seg = client->segments;

        if (prev_seg != NULL)
                agp_remove_seg_from_client(client);

        DBG("Adding seg %p (%d segments) to client %p", seg, num_segments, client);
        client->num_segments = num_segments;
        client->segments = seg;
}

static pgprot_t agp_convert_mmap_flags(int prot)
{
        unsigned long prot_bits;

        prot_bits = calc_vm_prot_bits(prot) | VM_SHARED;
        return vm_get_page_prot(prot_bits);
}

int agp_create_segment(struct agp_client *client, struct agp_region *region)
{
        struct agp_segment_priv **ret_seg;
        struct agp_segment_priv *seg;
        struct agp_segment *user_seg;
        size_t i;

        seg = kzalloc((sizeof(struct agp_segment_priv) * region->seg_count), GFP_KERNEL);
        if (seg == NULL) {
                kfree(region->seg_list);
                region->seg_list = NULL;
                return -ENOMEM;
        }
        user_seg = region->seg_list;

        for (i = 0; i < region->seg_count; i++) {
                seg[i].pg_start = user_seg[i].pg_start;
                seg[i].pg_count = user_seg[i].pg_count;
                seg[i].prot = agp_convert_mmap_flags(user_seg[i].prot);
        }
        kfree(region->seg_list);
        region->seg_list = NULL;

        ret_seg = kmalloc(sizeof(void *), GFP_KERNEL);
        if (ret_seg == NULL) {
                kfree(seg);
                return -ENOMEM;
        }
        *ret_seg = seg;
        agp_add_seg_to_client(client, ret_seg, region->seg_count);
        return 0;
}

/* End - Routines for managing each client's segment list */

/* This function must only be called when current_controller != NULL */
static void agp_insert_into_pool(struct agp_memory * temp)
{
        struct agp_memory *prev;

        prev = agp_fe.current_controller->pool;

        if (prev != NULL) {
                prev->prev = temp;
                temp->next = prev;
        }
        agp_fe.current_controller->pool = temp;
}


/* File private list routines */

struct agp_file_private *agp_find_private(pid_t pid)
{
        struct agp_file_private *curr;

        curr = agp_fe.file_priv_list;

        while (curr != NULL) {
                if (curr->my_pid == pid)
                        return curr;
                curr = curr->next;
        }

        return NULL;
}

static void agp_insert_file_private(struct agp_file_private * priv)
{
        struct agp_file_private *prev;

        prev = agp_fe.file_priv_list;

        if (prev != NULL)
                prev->prev = priv;
        priv->next = prev;
        agp_fe.file_priv_list = priv;
}

static void agp_remove_file_private(struct agp_file_private * priv)
{
        struct agp_file_private *next;
        struct agp_file_private *prev;

        next = priv->next;
        prev = priv->prev;

        if (prev != NULL) {
                prev->next = next;

                if (next != NULL)
                        next->prev = prev;

        } else {
                if (next != NULL)
                        next->prev = NULL;

                agp_fe.file_priv_list = next;
        }
}

/* End - File flag list routines */

/*
 * Wrappers for agp_free_memory & agp_allocate_memory
 * These make sure that internal lists are kept updated.
 */
void agp_free_memory_wrap(struct agp_memory *memory)
{
        agp_remove_from_pool(memory);
        agp_free_memory(memory);
}

struct agp_memory *agp_allocate_memory_wrap(size_t pg_count, u32 type)
{
        struct agp_memory *memory;

        memory = agp_allocate_memory(agp_bridge, pg_count, type);
        if (memory == NULL)
                return NULL;

        agp_insert_into_pool(memory);
        return memory;
}

/* Routines for managing the list of controllers -
 * These routines manage the current controller, and the list of
 * controllers
 */

static struct agp_controller *agp_find_controller_by_pid(pid_t id)
{
        struct agp_controller *controller;

        controller = agp_fe.controllers;

        while (controller != NULL) {
                if (controller->pid == id)
                        return controller;
                controller = controller->next;
        }

        return NULL;
}

static struct agp_controller *agp_create_controller(pid_t id)
{
        struct agp_controller *controller;

        controller = kzalloc(sizeof(struct agp_controller), GFP_KERNEL);
        if (controller == NULL)
                return NULL;

        controller->pid = id;
        return controller;
}

static int agp_insert_controller(struct agp_controller *controller)
{
        struct agp_controller *prev_controller;

        prev_controller = agp_fe.controllers;
        controller->next = prev_controller;

        if (prev_controller != NULL)
                prev_controller->prev = controller;

        agp_fe.controllers = controller;

        return 0;
}

static void agp_remove_all_clients(struct agp_controller *controller)
{
        struct agp_client *client;
        struct agp_client *temp;

        client = controller->clients;

        while (client) {
                struct agp_file_private *priv;

                temp = client;
                agp_remove_seg_from_client(temp);
                priv = agp_find_private(temp->pid);

                if (priv != NULL) {
                        clear_bit(AGP_FF_IS_VALID, &priv->access_flags);
                        clear_bit(AGP_FF_IS_CLIENT, &priv->access_flags);
                }
                client = client->next;
                kfree(temp);
        }
}

static void agp_remove_all_memory(struct agp_controller *controller)
{
        struct agp_memory *memory;
        struct agp_memory *temp;

        memory = controller->pool;

        while (memory) {
                temp = memory;
                memory = memory->next;
                agp_free_memory_wrap(temp);
        }
}

static int agp_remove_controller(struct agp_controller *controller)
{
        struct agp_controller *prev_controller;
        struct agp_controller *next_controller;

        prev_controller = controller->prev;
        next_controller = controller->next;

        if (prev_controller != NULL) {
                prev_controller->next = next_controller;
                if (next_controller != NULL)
                        next_controller->prev = prev_controller;

        } else {
                if (next_controller != NULL)
                        next_controller->prev = NULL;

                agp_fe.controllers = next_controller;
        }

        agp_remove_all_memory(controller);
        agp_remove_all_clients(controller);

        if (agp_fe.current_controller == controller) {
                agp_fe.current_controller = NULL;
                agp_fe.backend_acquired = false;
                agp_backend_release(agp_bridge);
        }
        kfree(controller);
        return 0;
}

static void agp_controller_make_current(struct agp_controller *controller)
{
        struct agp_client *clients;

        clients = controller->clients;

        while (clients != NULL) {
                struct agp_file_private *priv;

                priv = agp_find_private(clients->pid);

                if (priv != NULL) {
                        set_bit(AGP_FF_IS_VALID, &priv->access_flags);
                        set_bit(AGP_FF_IS_CLIENT, &priv->access_flags);
                }
                clients = clients->next;
        }

        agp_fe.current_controller = controller;
}

static void agp_controller_release_current(struct agp_controller *controller,
                                      struct agp_file_private *controller_priv)
{
        struct agp_client *clients;

        clear_bit(AGP_FF_IS_VALID, &controller_priv->access_flags);
        clients = controller->clients;

        while (clients != NULL) {
                struct agp_file_private *priv;

                priv = agp_find_private(clients->pid);

                if (priv != NULL)
                        clear_bit(AGP_FF_IS_VALID, &priv->access_flags);

                clients = clients->next;
        }

        agp_fe.current_controller = NULL;
        agp_fe.used_by_controller = false;
        agp_backend_release(agp_bridge);
}

/*
 * Routines for managing client lists -
 * These routines are for managing the list of auth'ed clients.
 */

static struct agp_client
*agp_find_client_in_controller(struct agp_controller *controller, pid_t id)
{
        struct agp_client *client;

        if (controller == NULL)
                return NULL;

        client = controller->clients;

        while (client != NULL) {
                if (client->pid == id)
                        return client;
                client = client->next;
        }

        return NULL;
}

static struct agp_controller *agp_find_controller_for_client(pid_t id)
{
        struct agp_controller *controller;

        controller = agp_fe.controllers;

        while (controller != NULL) {
                if ((agp_find_client_in_controller(controller, id)) != NULL)
                        return controller;
                controller = controller->next;
        }

        return NULL;
}

struct agp_client *agp_find_client_by_pid(pid_t id)
{
        struct agp_client *temp;

        if (agp_fe.current_controller == NULL)
                return NULL;

        temp = agp_find_client_in_controller(agp_fe.current_controller, id);
        return temp;
}

static void agp_insert_client(struct agp_client *client)
{
        struct agp_client *prev_client;

        prev_client = agp_fe.current_controller->clients;
        client->next = prev_client;

        if (prev_client != NULL)
                prev_client->prev = client;

        agp_fe.current_controller->clients = client;
        agp_fe.current_controller->num_clients++;
}

struct agp_client *agp_create_client(pid_t id)
{
        struct agp_client *new_client;

        new_client = kzalloc(sizeof(struct agp_client), GFP_KERNEL);
        if (new_client == NULL)
                return NULL;

        new_client->pid = id;
        agp_insert_client(new_client);
        return new_client;
}

int agp_remove_client(pid_t id)
{
        struct agp_client *client;
        struct agp_client *prev_client;
        struct agp_client *next_client;
        struct agp_controller *controller;

        controller = agp_find_controller_for_client(id);
        if (controller == NULL)
                return -EINVAL;

        client = agp_find_client_in_controller(controller, id);
        if (client == NULL)
                return -EINVAL;

        prev_client = client->prev;
        next_client = client->next;

        if (prev_client != NULL) {
                prev_client->next = next_client;
                if (next_client != NULL)
                        next_client->prev = prev_client;

        } else {
                if (next_client != NULL)
                        next_client->prev = NULL;
                controller->clients = next_client;
        }

        controller->num_clients--;
        agp_remove_seg_from_client(client);
        kfree(client);
        return 0;
}

/* End - Routines for managing client lists */

/* File Operations */

static int agp_mmap(struct file *file, struct vm_area_struct *vma)
{
        unsigned int size, current_size;
        unsigned long offset;
        struct agp_client *client;
        struct agp_file_private *priv = file->private_data;
        struct agp_kern_info kerninfo;

        mutex_lock(&(agp_fe.agp_mutex));

        if (agp_fe.backend_acquired != true)
                goto out_eperm;

        if (!(test_bit(AGP_FF_IS_VALID, &priv->access_flags)))
                goto out_eperm;

        agp_copy_info(agp_bridge, &kerninfo);
        size = vma->vm_end - vma->vm_start;
        current_size = kerninfo.aper_size;
        current_size = current_size * 0x100000;
        offset = vma->vm_pgoff << PAGE_SHIFT;
        DBG("%lx:%lx", offset, offset+size);

        if (test_bit(AGP_FF_IS_CLIENT, &priv->access_flags)) {
                if ((size + offset) > current_size)
                        goto out_inval;

                client = agp_find_client_by_pid(current->pid);

                if (client == NULL)
                        goto out_eperm;

                if (!agp_find_seg_in_client(client, offset, size, vma->vm_page_prot))
                        goto out_inval;

                DBG("client vm_ops=%p", kerninfo.vm_ops);
                if (kerninfo.vm_ops) {
                        vma->vm_ops = kerninfo.vm_ops;
                } else if (io_remap_pfn_range(vma, vma->vm_start,
                                (kerninfo.aper_base + offset) >> PAGE_SHIFT,
                                size,
                                pgprot_writecombine(vma->vm_page_prot))) {
                        goto out_again;
                }
                mutex_unlock(&(agp_fe.agp_mutex));
                return 0;
        }

        if (test_bit(AGP_FF_IS_CONTROLLER, &priv->access_flags)) {
                if (size != current_size)
                        goto out_inval;

                DBG("controller vm_ops=%p", kerninfo.vm_ops);
                if (kerninfo.vm_ops) {
                        vma->vm_ops = kerninfo.vm_ops;
                } else if (io_remap_pfn_range(vma, vma->vm_start,
                                kerninfo.aper_base >> PAGE_SHIFT,
                                size,
                                pgprot_writecombine(vma->vm_page_prot))) {
                        goto out_again;
                }
                mutex_unlock(&(agp_fe.agp_mutex));
                return 0;
        }

out_eperm:
        mutex_unlock(&(agp_fe.agp_mutex));
        return -EPERM;

out_inval:
        mutex_unlock(&(agp_fe.agp_mutex));
        return -EINVAL;

out_again:
        mutex_unlock(&(agp_fe.agp_mutex));
        return -EAGAIN;
}

static int agp_release(struct inode *inode, struct file *file)
{
        struct agp_file_private *priv = file->private_data;

        mutex_lock(&(agp_fe.agp_mutex));

        DBG("priv=%p", priv);

        if (test_bit(AGP_FF_IS_CONTROLLER, &priv->access_flags)) {
                struct agp_controller *controller;

                controller = agp_find_controller_by_pid(priv->my_pid);

                if (controller != NULL) {
                        if (controller == agp_fe.current_controller)
                                agp_controller_release_current(controller, priv);
                        agp_remove_controller(controller);
                        controller = NULL;
                }
        }

        if (test_bit(AGP_FF_IS_CLIENT, &priv->access_flags))
                agp_remove_client(priv->my_pid);

        agp_remove_file_private(priv);
        kfree(priv);
        file->private_data = NULL;
        mutex_unlock(&(agp_fe.agp_mutex));
        return 0;
}

static int agp_open(struct inode *inode, struct file *file)
{
        int minor = iminor(inode);
        struct agp_file_private *priv;
        struct agp_client *client;

        if (minor != AGPGART_MINOR)
                return -ENXIO;

        mutex_lock(&(agp_fe.agp_mutex));

        priv = kzalloc(sizeof(struct agp_file_private), GFP_KERNEL);
        if (priv == NULL) {
                mutex_unlock(&(agp_fe.agp_mutex));
                return -ENOMEM;
        }

        set_bit(AGP_FF_ALLOW_CLIENT, &priv->access_flags);
        priv->my_pid = current->pid;

        if (capable(CAP_SYS_RAWIO))
                /* Root priv, can be controller */
                set_bit(AGP_FF_ALLOW_CONTROLLER, &priv->access_flags);

        client = agp_find_client_by_pid(current->pid);

        if (client != NULL) {
                set_bit(AGP_FF_IS_CLIENT, &priv->access_flags);
                set_bit(AGP_FF_IS_VALID, &priv->access_flags);
        }
        file->private_data = (void *) priv;
        agp_insert_file_private(priv);
        DBG("private=%p, client=%p", priv, client);

        mutex_unlock(&(agp_fe.agp_mutex));

        return 0;
}


static ssize_t agp_read(struct file *file, char __user *buf,
                        size_t count, loff_t * ppos)
{
        return -EINVAL;
}

static ssize_t agp_write(struct file *file, const char __user *buf,
                         size_t count, loff_t * ppos)
{
        return -EINVAL;
}

static int agpioc_info_wrap(struct agp_file_private *priv, void __user *arg)
{
        struct agp_info userinfo;
        struct agp_kern_info kerninfo;

        agp_copy_info(agp_bridge, &kerninfo);

        userinfo.version.major = kerninfo.version.major;
        userinfo.version.minor = kerninfo.version.minor;
        userinfo.bridge_id = kerninfo.device->vendor |
            (kerninfo.device->device << 16);
        userinfo.agp_mode = kerninfo.mode;
        userinfo.aper_base = kerninfo.aper_base;
        userinfo.aper_size = kerninfo.aper_size;
        userinfo.pg_total = userinfo.pg_system = kerninfo.max_memory;
        userinfo.pg_used = kerninfo.current_memory;

        if (copy_to_user(arg, &userinfo, sizeof(struct agp_info)))
                return -EFAULT;

        return 0;
}

int agpioc_acquire_wrap(struct agp_file_private *priv)
{
        struct agp_controller *controller;

        DBG("");

        if (!(test_bit(AGP_FF_ALLOW_CONTROLLER, &priv->access_flags)))
                return -EPERM;

        if (agp_fe.current_controller != NULL)
                return -EBUSY;

        if (!agp_bridge)
                return -ENODEV;

        if (atomic_read(&agp_bridge->agp_in_use))
                return -EBUSY;

        atomic_inc(&agp_bridge->agp_in_use);

        agp_fe.backend_acquired = true;

        controller = agp_find_controller_by_pid(priv->my_pid);

        if (controller != NULL) {
                agp_controller_make_current(controller);
        } else {
                controller = agp_create_controller(priv->my_pid);

                if (controller == NULL) {
                        agp_fe.backend_acquired = false;
                        agp_backend_release(agp_bridge);
                        return -ENOMEM;
                }
                agp_insert_controller(controller);
                agp_controller_make_current(controller);
        }

        set_bit(AGP_FF_IS_CONTROLLER, &priv->access_flags);
        set_bit(AGP_FF_IS_VALID, &priv->access_flags);
        return 0;
}

int agpioc_release_wrap(struct agp_file_private *priv)
{
        DBG("");
        agp_controller_release_current(agp_fe.current_controller, priv);
        return 0;
}

int agpioc_setup_wrap(struct agp_file_private *priv, void __user *arg)
{
        struct agp_setup mode;

        DBG("");
        if (copy_from_user(&mode, arg, sizeof(struct agp_setup)))
                return -EFAULT;

        agp_enable(agp_bridge, mode.agp_mode);
        return 0;
}

static int agpioc_reserve_wrap(struct agp_file_private *priv, void __user *arg)
{
        struct agp_region reserve;
        struct agp_client *client;
        struct agp_file_private *client_priv;

        DBG("");
        if (copy_from_user(&reserve, arg, sizeof(struct agp_region)))
                return -EFAULT;

        if ((unsigned) reserve.seg_count >= ~0U/sizeof(struct agp_segment))
                return -EFAULT;

        client = agp_find_client_by_pid(reserve.pid);

        if (reserve.seg_count == 0) {
                /* remove a client */
                client_priv = agp_find_private(reserve.pid);

                if (client_priv != NULL) {
                        set_bit(AGP_FF_IS_CLIENT, &client_priv->access_flags);
                        set_bit(AGP_FF_IS_VALID, &client_priv->access_flags);
                }
                if (client == NULL) {
                        /* client is already removed */
                        return 0;
                }
                return agp_remove_client(reserve.pid);
        } else {
                struct agp_segment *segment;

                if (reserve.seg_count >= 16384)
                        return -EINVAL;

                segment = kmalloc((sizeof(struct agp_segment) * reserve.seg_count),
                                  GFP_KERNEL);

                if (segment == NULL)
                        return -ENOMEM;

                if (copy_from_user(segment, (void __user *) reserve.seg_list,
                                   sizeof(struct agp_segment) * reserve.seg_count)) {
                        kfree(segment);
                        return -EFAULT;
                }
                reserve.seg_list = segment;

                if (client == NULL) {
                        /* Create the client and add the segment */
                        client = agp_create_client(reserve.pid);

                        if (client == NULL) {
                                kfree(segment);
                                return -ENOMEM;
                        }
                        client_priv = agp_find_private(reserve.pid);

                        if (client_priv != NULL) {
                                set_bit(AGP_FF_IS_CLIENT, &client_priv->access_flags);
                                set_bit(AGP_FF_IS_VALID, &client_priv->access_flags);
                        }
                }
                return agp_create_segment(client, &reserve);
        }
        /* Will never really happen */
        return -EINVAL;
}

int agpioc_protect_wrap(struct agp_file_private *priv)
{
        DBG("");
        /* This function is not currently implemented */
        return -EINVAL;
}

static int agpioc_allocate_wrap(struct agp_file_private *priv, void __user *arg)
{
        struct agp_memory *memory;
        struct agp_allocate alloc;

        DBG("");
        if (copy_from_user(&alloc, arg, sizeof(struct agp_allocate)))
                return -EFAULT;

        if (alloc.type >= AGP_USER_TYPES)
                return -EINVAL;

        memory = agp_allocate_memory_wrap(alloc.pg_count, alloc.type);

        if (memory == NULL)
                return -ENOMEM;

        alloc.key = memory->key;
        alloc.physical = memory->physical;

        if (copy_to_user(arg, &alloc, sizeof(struct agp_allocate))) {
                agp_free_memory_wrap(memory);
                return -EFAULT;
        }
        return 0;
}

int agpioc_deallocate_wrap(struct agp_file_private *priv, int arg)
{
        struct agp_memory *memory;

        DBG("");
        memory = agp_find_mem_by_key(arg);

        if (memory == NULL)
                return -EINVAL;

        agp_free_memory_wrap(memory);
        return 0;
}

static int agpioc_bind_wrap(struct agp_file_private *priv, void __user *arg)
{
        struct agp_bind bind_info;
        struct agp_memory *memory;

        DBG("");
        if (copy_from_user(&bind_info, arg, sizeof(struct agp_bind)))
                return -EFAULT;

        memory = agp_find_mem_by_key(bind_info.key);

        if (memory == NULL)
                return -EINVAL;

        return agp_bind_memory(memory, bind_info.pg_start);
}

static int agpioc_unbind_wrap(struct agp_file_private *priv, void __user *arg)
{
        struct agp_memory *memory;
        struct agp_unbind unbind;

        DBG("");
        if (copy_from_user(&unbind, arg, sizeof(struct agp_unbind)))
                return -EFAULT;

        memory = agp_find_mem_by_key(unbind.key);

        if (memory == NULL)
                return -EINVAL;

        return agp_unbind_memory(memory);
}

static long agp_ioctl(struct file *file,
                     unsigned int cmd, unsigned long arg)
{
        struct agp_file_private *curr_priv = file->private_data;
        int ret_val = -ENOTTY;

        DBG("priv=%p, cmd=%x", curr_priv, cmd);
        mutex_lock(&(agp_fe.agp_mutex));

        if ((agp_fe.current_controller == NULL) &&
            (cmd != AGPIOC_ACQUIRE)) {
                ret_val = -EINVAL;
                goto ioctl_out;
        }
        if ((agp_fe.backend_acquired != true) &&
            (cmd != AGPIOC_ACQUIRE)) {
                ret_val = -EBUSY;
                goto ioctl_out;
        }
        if (cmd != AGPIOC_ACQUIRE) {
                if (!(test_bit(AGP_FF_IS_CONTROLLER, &curr_priv->access_flags))) {
                        ret_val = -EPERM;
                        goto ioctl_out;
                }
                /* Use the original pid of the controller,
                 * in case it's threaded */

                if (agp_fe.current_controller->pid != curr_priv->my_pid) {
                        ret_val = -EBUSY;
                        goto ioctl_out;
                }
        }

        switch (cmd) {
        case AGPIOC_INFO:
                ret_val = agpioc_info_wrap(curr_priv, (void __user *) arg);
                break;

        case AGPIOC_ACQUIRE:

                ret_val = agpioc_acquire_wrap(curr_priv);
                break;

        case AGPIOC_RELEASE:
                ret_val = agpioc_release_wrap(curr_priv);
                break;

        case AGPIOC_SETUP:
                ret_val = agpioc_setup_wrap(curr_priv, (void __user *) arg);
                break;

        case AGPIOC_RESERVE:
                ret_val = agpioc_reserve_wrap(curr_priv, (void __user *) arg);
                break;

        case AGPIOC_PROTECT:
                ret_val = agpioc_protect_wrap(curr_priv);
                break;

        case AGPIOC_ALLOCATE:
                ret_val = agpioc_allocate_wrap(curr_priv, (void __user *) arg);
                break;

        case AGPIOC_DEALLOCATE:
                ret_val = agpioc_deallocate_wrap(curr_priv, (int) arg);
                break;

        case AGPIOC_BIND:
                ret_val = agpioc_bind_wrap(curr_priv, (void __user *) arg);
                break;

        case AGPIOC_UNBIND:
                ret_val = agpioc_unbind_wrap(curr_priv, (void __user *) arg);
                break;
               
        case AGPIOC_CHIPSET_FLUSH:
                break;
        }

ioctl_out:
        DBG("ioctl returns %d\n", ret_val);
        mutex_unlock(&(agp_fe.agp_mutex));
        return ret_val;
}

static const struct file_operations agp_fops =
{
        .owner          = THIS_MODULE,
        .llseek         = no_llseek,
        .read           = agp_read,
        .write          = agp_write,
        .unlocked_ioctl = agp_ioctl,
#ifdef CONFIG_COMPAT
        .compat_ioctl   = compat_agp_ioctl,
#endif
        .mmap           = agp_mmap,
        .open           = agp_open,
        .release        = agp_release,
};

static struct miscdevice agp_miscdev =
{
        .minor  = AGPGART_MINOR,
        .name   = "agpgart",
        .fops   = &agp_fops
};

int agp_frontend_initialize(void)
{
        memset(&agp_fe, 0, sizeof(struct agp_front_data));
        mutex_init(&(agp_fe.agp_mutex));

        if (misc_register(&agp_miscdev)) {
                printk(KERN_ERR PFX "unable to get minor: %d\n", AGPGART_MINOR);
                return -EIO;
        }
        return 0;
}

void agp_frontend_cleanup(void)
{
        misc_deregister(&agp_miscdev);
}