frontend.c

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/*
 * 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, 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, 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);
}