drivers/char/agp/frontend.c

/*
 * 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/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 <linux/uaccess.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 i;
	off_t pg_start;
	size_t pg_count;

	pg_start = offset / 4096;
	pg_count = size / 4096;
	seg = *(client->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, 0) | 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 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);

	memset(&userinfo, 0, sizeof(userinfo));
	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,
	.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);
}