drivers/char/drm/drm_agpsupport.c - kernel/msm - Gitiles

 /**
  * \file drm_agpsupport.h
  * DRM support for AGP/GART backend
  *
  * \author Rickard E. (Rik) Faith <faith@valinux.com>
  * \author Gareth Hughes <gareth@valinux.com>
  */

 /*
  * Copyright 1999 Precision Insight, Inc., Cedar Park, Texas.
  * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
  * All Rights Reserved.
  *
  * 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 (including the next
  * paragraph) 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
  * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS 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 "drmP.h"
 #include <linux/module.h>

 #if __OS_HAS_AGP

 /**
  * AGP information ioctl.
  *
  * \param inode device inode.
  * \param filp file pointer.
  * \param cmd command.
  * \param arg pointer to a (output) drm_agp_info structure.
  * \return zero on success or a negative number on failure.
  *
  * Verifies the AGP device has been initialized and acquired and fills in the
  * drm_agp_info structure with the information in drm_agp_head::agp_info.
  */
 int drm_agp_info(struct inode *inode, struct file *filp,
 		  unsigned int cmd, unsigned long arg)
 {
 	drm_file_t	 *priv	 = filp->private_data;
 	drm_device_t	 *dev	 = priv->head->dev;
 	DRM_AGP_KERN     *kern;
 	drm_agp_info_t   info;

 	if (!dev->agp || !dev->agp->acquired)
 		return -EINVAL;

 	kern                   = &dev->agp->agp_info;
 	info.agp_version_major = kern->version.major;
 	info.agp_version_minor = kern->version.minor;
 	info.mode              = kern->mode;
 	info.aperture_base     = kern->aper_base;
 	info.aperture_size     = kern->aper_size * 1024 * 1024;
 	info.memory_allowed    = kern->max_memory << PAGE_SHIFT;
 	info.memory_used       = kern->current_memory << PAGE_SHIFT;
 	info.id_vendor         = kern->device->vendor;
 	info.id_device         = kern->device->device;

 	if (copy_to_user((drm_agp_info_t __user *)arg, &info, sizeof(info)))
 		return -EFAULT;
 	return 0;
 }

 /**
  * Acquire the AGP device (ioctl).
  *
  * \param inode device inode.
  * \param filp file pointer.
  * \param cmd command.
  * \param arg user argument.
  * \return zero on success or a negative number on failure.
  *
  * Verifies the AGP device hasn't been acquired before and calls
  * agp_acquire().
  */
 int drm_agp_acquire(struct inode *inode, struct file *filp,
 		     unsigned int cmd, unsigned long arg)
 {
 	drm_file_t	 *priv	 = filp->private_data;
 	drm_device_t	 *dev	 = priv->head->dev;

 	if (!dev->agp)
 		return -ENODEV;
 	if (dev->agp->acquired)
 		return -EBUSY;
 	if (!(dev->agp->bridge = agp_backend_acquire(dev->pdev)))
 		return -ENODEV;
 	dev->agp->acquired = 1;
 	return 0;
 }

 /**
  * Release the AGP device (ioctl).
  *
  * \param inode device inode.
  * \param filp file pointer.
  * \param cmd command.
  * \param arg user argument.
  * \return zero on success or a negative number on failure.
  *
  * Verifies the AGP device has been acquired and calls agp_backend_release().
  */
 int drm_agp_release(struct inode *inode, struct file *filp,
 		     unsigned int cmd, unsigned long arg)
 {
 	drm_file_t	 *priv	 = filp->private_data;
 	drm_device_t	 *dev	 = priv->head->dev;

 	if (!dev->agp || !dev->agp->acquired)
 		return -EINVAL;
 	agp_backend_release(dev->agp->bridge);
 	dev->agp->acquired = 0;
 	return 0;

 }

 /**
  * Release the AGP device.
  *
  * Calls agp_backend_release().
  */
 void drm_agp_do_release(drm_device_t *dev)
 {
   agp_backend_release(dev->agp->bridge);
 }

 /**
  * Enable the AGP bus.
  *
  * \param inode device inode.
  * \param filp file pointer.
  * \param cmd command.
  * \param arg pointer to a drm_agp_mode structure.
  * \return zero on success or a negative number on failure.
  *
  * Verifies the AGP device has been acquired but not enabled, and calls
  * agp_enable().
  */
 int drm_agp_enable(struct inode *inode, struct file *filp,
 		    unsigned int cmd, unsigned long arg)
 {
 	drm_file_t	 *priv	 = filp->private_data;
 	drm_device_t	 *dev	 = priv->head->dev;
 	drm_agp_mode_t   mode;

 	if (!dev->agp || !dev->agp->acquired)
 		return -EINVAL;

 	if (copy_from_user(&mode, (drm_agp_mode_t __user *)arg, sizeof(mode)))
 		return -EFAULT;

 	dev->agp->mode    = mode.mode;
 	agp_enable(dev->agp->bridge, mode.mode);
 	dev->agp->base    = dev->agp->agp_info.aper_base;
 	dev->agp->enabled = 1;
 	return 0;
 }

 /**
  * Allocate AGP memory.
  *
  * \param inode device inode.
  * \param filp file pointer.
  * \param cmd command.
  * \param arg pointer to a drm_agp_buffer structure.
  * \return zero on success or a negative number on failure.
  *
  * Verifies the AGP device is present and has been acquired, allocates the
  * memory via alloc_agp() and creates a drm_agp_mem entry for it.
  */
 int drm_agp_alloc(struct inode *inode, struct file *filp,
 		   unsigned int cmd, unsigned long arg)
 {
 	drm_file_t	 *priv	 = filp->private_data;
 	drm_device_t	 *dev	 = priv->head->dev;
 	drm_agp_buffer_t request;
 	drm_agp_mem_t    *entry;
 	DRM_AGP_MEM      *memory;
 	unsigned long    pages;
 	u32 		 type;
 	drm_agp_buffer_t __user *argp = (void __user *)arg;

 	if (!dev->agp || !dev->agp->acquired)
 		return -EINVAL;
 	if (copy_from_user(&request, argp, sizeof(request)))
 		return -EFAULT;
 	if (!(entry = drm_alloc(sizeof(*entry), DRM_MEM_AGPLISTS)))
 		return -ENOMEM;

    	memset(entry, 0, sizeof(*entry));

 	pages = (request.size + PAGE_SIZE - 1) / PAGE_SIZE;
 	type = (u32) request.type;

 	if (!(memory = drm_alloc_agp(dev->agp->bridge, pages, type))) {
 		drm_free(entry, sizeof(*entry), DRM_MEM_AGPLISTS);
 		return -ENOMEM;
 	}

 	entry->handle    = (unsigned long)memory->key + 1;
 	entry->memory    = memory;
 	entry->bound     = 0;
 	entry->pages     = pages;
 	entry->prev      = NULL;
 	entry->next      = dev->agp->memory;
 	if (dev->agp->memory)
 		dev->agp->memory->prev = entry;
 	dev->agp->memory = entry;

 	request.handle   = entry->handle;
 	request.physical = memory->physical;

 	if (copy_to_user(argp, &request, sizeof(request))) {
 		dev->agp->memory       = entry->next;
 		dev->agp->memory->prev = NULL;
 		drm_free_agp(memory, pages);
 		drm_free(entry, sizeof(*entry), DRM_MEM_AGPLISTS);
 		return -EFAULT;
 	}
 	return 0;
 }

 /**
  * Search for the AGP memory entry associated with a handle.
  *
  * \param dev DRM device structure.
  * \param handle AGP memory handle.
  * \return pointer to the drm_agp_mem structure associated with \p handle.
  *
  * Walks through drm_agp_head::memory until finding a matching handle.
  */
 static drm_agp_mem_t *drm_agp_lookup_entry(drm_device_t *dev,
 					    unsigned long handle)
 {
 	drm_agp_mem_t *entry;

 	for (entry = dev->agp->memory; entry; entry = entry->next) {
 		if (entry->handle == handle)
 			return entry;
 	}
 	return NULL;
 }

 /**
  * Unbind AGP memory from the GATT (ioctl).
  *
  * \param inode device inode.
  * \param filp file pointer.
  * \param cmd command.
  * \param arg pointer to a drm_agp_binding structure.
  * \return zero on success or a negative number on failure.
  *
  * Verifies the AGP device is present and acquired, looks-up the AGP memory
  * entry and passes it to the unbind_agp() function.
  */
 int drm_agp_unbind(struct inode *inode, struct file *filp,
 		    unsigned int cmd, unsigned long arg)
 {
 	drm_file_t	  *priv	 = filp->private_data;
 	drm_device_t	  *dev	 = priv->head->dev;
 	drm_agp_binding_t request;
 	drm_agp_mem_t     *entry;
 	int ret;

 	if (!dev->agp || !dev->agp->acquired)
 		return -EINVAL;
 	if (copy_from_user(&request, (drm_agp_binding_t __user *)arg, sizeof(request)))
 		return -EFAULT;
 	if (!(entry = drm_agp_lookup_entry(dev, request.handle)))
 		return -EINVAL;
 	if (!entry->bound)
 		return -EINVAL;
 	ret = drm_unbind_agp(entry->memory);
 	if (ret == 0)
 	    entry->bound = 0;
 	return ret;
 }

 /**
  * Bind AGP memory into the GATT (ioctl)
  *
  * \param inode device inode.
  * \param filp file pointer.
  * \param cmd command.
  * \param arg pointer to a drm_agp_binding structure.
  * \return zero on success or a negative number on failure.
  *
  * Verifies the AGP device is present and has been acquired and that no memory
  * is currently bound into the GATT. Looks-up the AGP memory entry and passes
  * it to bind_agp() function.
  */
 int drm_agp_bind(struct inode *inode, struct file *filp,
 		  unsigned int cmd, unsigned long arg)
 {
 	drm_file_t	  *priv	 = filp->private_data;
 	drm_device_t	  *dev	 = priv->head->dev;
 	drm_agp_binding_t request;
 	drm_agp_mem_t     *entry;
 	int               retcode;
 	int               page;

 	if (!dev->agp || !dev->agp->acquired)
 		return -EINVAL;
 	if (copy_from_user(&request, (drm_agp_binding_t __user *)arg, sizeof(request)))
 		return -EFAULT;
 	if (!(entry = drm_agp_lookup_entry(dev, request.handle)))
 		return -EINVAL;
 	if (entry->bound)
 		return -EINVAL;
 	page = (request.offset + PAGE_SIZE - 1) / PAGE_SIZE;
 	if ((retcode = drm_bind_agp(entry->memory, page)))
 		return retcode;
 	entry->bound = dev->agp->base + (page << PAGE_SHIFT);
 	DRM_DEBUG("base = 0x%lx entry->bound = 0x%lx\n",
 		  dev->agp->base, entry->bound);
 	return 0;
 }

 /**
  * Free AGP memory (ioctl).
  *
  * \param inode device inode.
  * \param filp file pointer.
  * \param cmd command.
  * \param arg pointer to a drm_agp_buffer structure.
  * \return zero on success or a negative number on failure.
  *
  * Verifies the AGP device is present and has been acquired and looks up the
  * AGP memory entry. If the memory it's currently bound, unbind it via
  * unbind_agp(). Frees it via free_agp() as well as the entry itself
  * and unlinks from the doubly linked list it's inserted in.
  */
 int drm_agp_free(struct inode *inode, struct file *filp,
 		  unsigned int cmd, unsigned long arg)
 {
 	drm_file_t	 *priv	 = filp->private_data;
 	drm_device_t	 *dev	 = priv->head->dev;
 	drm_agp_buffer_t request;
 	drm_agp_mem_t    *entry;

 	if (!dev->agp || !dev->agp->acquired)
 		return -EINVAL;
 	if (copy_from_user(&request, (drm_agp_buffer_t __user *)arg, sizeof(request)))
 		return -EFAULT;
 	if (!(entry = drm_agp_lookup_entry(dev, request.handle)))
 		return -EINVAL;
 	if (entry->bound)
 		drm_unbind_agp(entry->memory);

 	if (entry->prev)
 		entry->prev->next = entry->next;
 	else
 		dev->agp->memory = entry->next;

 	if (entry->next)
 		entry->next->prev = entry->prev;

 	drm_free_agp(entry->memory, entry->pages);
 	drm_free(entry, sizeof(*entry), DRM_MEM_AGPLISTS);
 	return 0;
 }

 /**
  * Initialize the AGP resources.
  *
  * \return pointer to a drm_agp_head structure.
  *
  */
 drm_agp_head_t *drm_agp_init(drm_device_t *dev)
 {
 	drm_agp_head_t *head         = NULL;

 	if (!(head = drm_alloc(sizeof(*head), DRM_MEM_AGPLISTS)))
 		return NULL;
 	memset((void *)head, 0, sizeof(*head));
 	head->bridge = agp_find_bridge(dev->pdev);
 	if (!head->bridge) {
 		if (!(head->bridge = agp_backend_acquire(dev->pdev))) {
 			drm_free(head, sizeof(*head), DRM_MEM_AGPLISTS);
 			return NULL;
 		}
 		agp_copy_info(head->bridge, &head->agp_info);
 		agp_backend_release(head->bridge);
 	} else {
 		agp_copy_info(head->bridge, &head->agp_info);
 	}
 	if (head->agp_info.chipset == NOT_SUPPORTED) {
 		drm_free(head, sizeof(*head), DRM_MEM_AGPLISTS);
 		return NULL;
 	}
 	head->memory = NULL;
 #if LINUX_VERSION_CODE <= 0x020408
 	head->cant_use_aperture = 0;
 	head->page_mask = ~(0xfff);
 #else
 	head->cant_use_aperture = head->agp_info.cant_use_aperture;
 	head->page_mask = head->agp_info.page_mask;
 #endif

 	return head;
 }

 /** Calls agp_allocate_memory() */
 DRM_AGP_MEM *drm_agp_allocate_memory(struct agp_bridge_data *bridge, size_t pages, u32 type)
 {
 	return agp_allocate_memory(bridge, pages, type);
 }

 /** Calls agp_free_memory() */
 int drm_agp_free_memory(DRM_AGP_MEM *handle)
 {
 	if (!handle)
 		return 0;
 	agp_free_memory(handle);
 	return 1;
 }

 /** Calls agp_bind_memory() */
 int drm_agp_bind_memory(DRM_AGP_MEM *handle, off_t start)
 {
 	if (!handle)
 		return -EINVAL;
 	return agp_bind_memory(handle, start);
 }

 /** Calls agp_unbind_memory() */
 int drm_agp_unbind_memory(DRM_AGP_MEM *handle)
 {
 	if (!handle)
 		return -EINVAL;
 	return agp_unbind_memory(handle);
 }

 #endif /* __OS_HAS_AGP */
	/**
	* \file drm_agpsupport.h
	* DRM support for AGP/GART backend
	*
	* \author Rickard E. (Rik) Faith <faith@valinux.com>
	* \author Gareth Hughes <gareth@valinux.com>
	*/

	/*
	* Copyright 1999 Precision Insight, Inc., Cedar Park, Texas.
	* Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
	* All Rights Reserved.
	*
	* 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 (including the next
	* paragraph) 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
	* VA LINUX SYSTEMS AND/OR ITS SUPPLIERS 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 "drmP.h"
	#include <linux/module.h>

	#if __OS_HAS_AGP

	/**
	* AGP information ioctl.
	*
	* \param inode device inode.
	* \param filp file pointer.
	* \param cmd command.
	* \param arg pointer to a (output) drm_agp_info structure.
	* \return zero on success or a negative number on failure.
	*
	* Verifies the AGP device has been initialized and acquired and fills in the
	* drm_agp_info structure with the information in drm_agp_head::agp_info.
	*/
	int drm_agp_info(struct inode inode, struct file filp,
	unsigned int cmd, unsigned long arg)
	{
	drm_file_t *priv = filp->private_data;
	drm_device_t *dev = priv->head->dev;
	DRM_AGP_KERN *kern;
	drm_agp_info_t info;

	if (!dev->agp \|\| !dev->agp->acquired)
	return -EINVAL;

	kern = &dev->agp->agp_info;
	info.agp_version_major = kern->version.major;
	info.agp_version_minor = kern->version.minor;
	info.mode = kern->mode;
	info.aperture_base = kern->aper_base;
	info.aperture_size = kern->aper_size * 1024 * 1024;
	info.memory_allowed = kern->max_memory << PAGE_SHIFT;
	info.memory_used = kern->current_memory << PAGE_SHIFT;
	info.id_vendor = kern->device->vendor;
	info.id_device = kern->device->device;

	if (copy_to_user((drm_agp_info_t __user *)arg, &info, sizeof(info)))
	return -EFAULT;
	return 0;
	}

	/**
	* Acquire the AGP device (ioctl).
	*
	* \param inode device inode.
	* \param filp file pointer.
	* \param cmd command.
	* \param arg user argument.
	* \return zero on success or a negative number on failure.
	*
	* Verifies the AGP device hasn't been acquired before and calls
	* agp_acquire().
	*/
	int drm_agp_acquire(struct inode inode, struct file filp,
	unsigned int cmd, unsigned long arg)
	{
	drm_file_t *priv = filp->private_data;
	drm_device_t *dev = priv->head->dev;

	if (!dev->agp)
	return -ENODEV;
	if (dev->agp->acquired)
	return -EBUSY;
	if (!(dev->agp->bridge = agp_backend_acquire(dev->pdev)))
	return -ENODEV;
	dev->agp->acquired = 1;
	return 0;
	}

	/**
	* Release the AGP device (ioctl).
	*
	* \param inode device inode.
	* \param filp file pointer.
	* \param cmd command.
	* \param arg user argument.
	* \return zero on success or a negative number on failure.
	*
	* Verifies the AGP device has been acquired and calls agp_backend_release().
	*/
	int drm_agp_release(struct inode inode, struct file filp,
	unsigned int cmd, unsigned long arg)
	{
	drm_file_t *priv = filp->private_data;
	drm_device_t *dev = priv->head->dev;

	if (!dev->agp \|\| !dev->agp->acquired)
	return -EINVAL;
	agp_backend_release(dev->agp->bridge);
	dev->agp->acquired = 0;
	return 0;

	}

	/**
	* Release the AGP device.
	*
	* Calls agp_backend_release().
	*/
	void drm_agp_do_release(drm_device_t *dev)
	{
	agp_backend_release(dev->agp->bridge);
	}

	/**
	* Enable the AGP bus.
	*
	* \param inode device inode.
	* \param filp file pointer.
	* \param cmd command.
	* \param arg pointer to a drm_agp_mode structure.
	* \return zero on success or a negative number on failure.
	*
	* Verifies the AGP device has been acquired but not enabled, and calls
	* agp_enable().
	*/
	int drm_agp_enable(struct inode inode, struct file filp,
	unsigned int cmd, unsigned long arg)
	{
	drm_file_t *priv = filp->private_data;
	drm_device_t *dev = priv->head->dev;
	drm_agp_mode_t mode;

	if (!dev->agp \|\| !dev->agp->acquired)
	return -EINVAL;

	if (copy_from_user(&mode, (drm_agp_mode_t __user *)arg, sizeof(mode)))
	return -EFAULT;

	dev->agp->mode = mode.mode;
	agp_enable(dev->agp->bridge, mode.mode);
	dev->agp->base = dev->agp->agp_info.aper_base;
	dev->agp->enabled = 1;
	return 0;
	}

	/**
	* Allocate AGP memory.
	*
	* \param inode device inode.
	* \param filp file pointer.
	* \param cmd command.
	* \param arg pointer to a drm_agp_buffer structure.
	* \return zero on success or a negative number on failure.
	*
	* Verifies the AGP device is present and has been acquired, allocates the
	* memory via alloc_agp() and creates a drm_agp_mem entry for it.
	*/
	int drm_agp_alloc(struct inode inode, struct file filp,
	unsigned int cmd, unsigned long arg)
	{
	drm_file_t *priv = filp->private_data;
	drm_device_t *dev = priv->head->dev;
	drm_agp_buffer_t request;
	drm_agp_mem_t *entry;
	DRM_AGP_MEM *memory;
	unsigned long pages;
	u32 type;
	drm_agp_buffer_t __user argp = (void __user )arg;

	if (!dev->agp \|\| !dev->agp->acquired)
	return -EINVAL;
	if (copy_from_user(&request, argp, sizeof(request)))
	return -EFAULT;
	if (!(entry = drm_alloc(sizeof(*entry), DRM_MEM_AGPLISTS)))
	return -ENOMEM;

	memset(entry, 0, sizeof(*entry));

	pages = (request.size + PAGE_SIZE - 1) / PAGE_SIZE;
	type = (u32) request.type;

	if (!(memory = drm_alloc_agp(dev->agp->bridge, pages, type))) {
	drm_free(entry, sizeof(*entry), DRM_MEM_AGPLISTS);
	return -ENOMEM;
	}

	entry->handle = (unsigned long)memory->key + 1;
	entry->memory = memory;
	entry->bound = 0;
	entry->pages = pages;
	entry->prev = NULL;
	entry->next = dev->agp->memory;
	if (dev->agp->memory)
	dev->agp->memory->prev = entry;
	dev->agp->memory = entry;

	request.handle = entry->handle;
	request.physical = memory->physical;

	if (copy_to_user(argp, &request, sizeof(request))) {
	dev->agp->memory = entry->next;
	dev->agp->memory->prev = NULL;
	drm_free_agp(memory, pages);
	drm_free(entry, sizeof(*entry), DRM_MEM_AGPLISTS);
	return -EFAULT;
	}
	return 0;
	}

	/**
	* Search for the AGP memory entry associated with a handle.
	*
	* \param dev DRM device structure.
	* \param handle AGP memory handle.
	* \return pointer to the drm_agp_mem structure associated with \p handle.
	*
	* Walks through drm_agp_head::memory until finding a matching handle.
	*/
	static drm_agp_mem_t drm_agp_lookup_entry(drm_device_t dev,
	unsigned long handle)
	{
	drm_agp_mem_t *entry;

	for (entry = dev->agp->memory; entry; entry = entry->next) {
	if (entry->handle == handle)
	return entry;
	}
	return NULL;
	}

	/**
	* Unbind AGP memory from the GATT (ioctl).
	*
	* \param inode device inode.
	* \param filp file pointer.
	* \param cmd command.
	* \param arg pointer to a drm_agp_binding structure.
	* \return zero on success or a negative number on failure.
	*
	* Verifies the AGP device is present and acquired, looks-up the AGP memory
	* entry and passes it to the unbind_agp() function.
	*/
	int drm_agp_unbind(struct inode inode, struct file filp,
	unsigned int cmd, unsigned long arg)
	{
	drm_file_t *priv = filp->private_data;
	drm_device_t *dev = priv->head->dev;
	drm_agp_binding_t request;
	drm_agp_mem_t *entry;
	int ret;

	if (!dev->agp \|\| !dev->agp->acquired)
	return -EINVAL;
	if (copy_from_user(&request, (drm_agp_binding_t __user *)arg, sizeof(request)))
	return -EFAULT;
	if (!(entry = drm_agp_lookup_entry(dev, request.handle)))
	return -EINVAL;
	if (!entry->bound)
	return -EINVAL;
	ret = drm_unbind_agp(entry->memory);
	if (ret == 0)
	entry->bound = 0;
	return ret;
	}

	/**
	* Bind AGP memory into the GATT (ioctl)
	*
	* \param inode device inode.
	* \param filp file pointer.
	* \param cmd command.
	* \param arg pointer to a drm_agp_binding structure.
	* \return zero on success or a negative number on failure.
	*
	* Verifies the AGP device is present and has been acquired and that no memory
	* is currently bound into the GATT. Looks-up the AGP memory entry and passes
	* it to bind_agp() function.
	*/
	int drm_agp_bind(struct inode inode, struct file filp,
	unsigned int cmd, unsigned long arg)
	{
	drm_file_t *priv = filp->private_data;
	drm_device_t *dev = priv->head->dev;
	drm_agp_binding_t request;
	drm_agp_mem_t *entry;
	int retcode;
	int page;

	if (!dev->agp \|\| !dev->agp->acquired)
	return -EINVAL;
	if (copy_from_user(&request, (drm_agp_binding_t __user *)arg, sizeof(request)))
	return -EFAULT;
	if (!(entry = drm_agp_lookup_entry(dev, request.handle)))
	return -EINVAL;
	if (entry->bound)
	return -EINVAL;
	page = (request.offset + PAGE_SIZE - 1) / PAGE_SIZE;
	if ((retcode = drm_bind_agp(entry->memory, page)))
	return retcode;
	entry->bound = dev->agp->base + (page << PAGE_SHIFT);
	DRM_DEBUG("base = 0x%lx entry->bound = 0x%lx\n",
	dev->agp->base, entry->bound);
	return 0;
	}

	/**
	* Free AGP memory (ioctl).
	*
	* \param inode device inode.
	* \param filp file pointer.
	* \param cmd command.
	* \param arg pointer to a drm_agp_buffer structure.
	* \return zero on success or a negative number on failure.
	*
	* Verifies the AGP device is present and has been acquired and looks up the
	* AGP memory entry. If the memory it's currently bound, unbind it via
	* unbind_agp(). Frees it via free_agp() as well as the entry itself
	* and unlinks from the doubly linked list it's inserted in.
	*/
	int drm_agp_free(struct inode inode, struct file filp,
	unsigned int cmd, unsigned long arg)
	{
	drm_file_t *priv = filp->private_data;
	drm_device_t *dev = priv->head->dev;
	drm_agp_buffer_t request;
	drm_agp_mem_t *entry;

	if (!dev->agp \|\| !dev->agp->acquired)
	return -EINVAL;
	if (copy_from_user(&request, (drm_agp_buffer_t __user *)arg, sizeof(request)))
	return -EFAULT;
	if (!(entry = drm_agp_lookup_entry(dev, request.handle)))
	return -EINVAL;
	if (entry->bound)
	drm_unbind_agp(entry->memory);

	if (entry->prev)
	entry->prev->next = entry->next;
	else
	dev->agp->memory = entry->next;

	if (entry->next)
	entry->next->prev = entry->prev;

	drm_free_agp(entry->memory, entry->pages);
	drm_free(entry, sizeof(*entry), DRM_MEM_AGPLISTS);
	return 0;
	}

	/**
	* Initialize the AGP resources.
	*
	* \return pointer to a drm_agp_head structure.
	*
	*/
	drm_agp_head_t drm_agp_init(drm_device_t dev)
	{
	drm_agp_head_t *head = NULL;

	if (!(head = drm_alloc(sizeof(*head), DRM_MEM_AGPLISTS)))
	return NULL;
	memset((void )head, 0, sizeof(head));
	head->bridge = agp_find_bridge(dev->pdev);
	if (!head->bridge) {
	if (!(head->bridge = agp_backend_acquire(dev->pdev))) {
	drm_free(head, sizeof(*head), DRM_MEM_AGPLISTS);
	return NULL;
	}
	agp_copy_info(head->bridge, &head->agp_info);
	agp_backend_release(head->bridge);
	} else {
	agp_copy_info(head->bridge, &head->agp_info);
	}
	if (head->agp_info.chipset == NOT_SUPPORTED) {
	drm_free(head, sizeof(*head), DRM_MEM_AGPLISTS);
	return NULL;
	}
	head->memory = NULL;
	#if LINUX_VERSION_CODE <= 0x020408
	head->cant_use_aperture = 0;
	head->page_mask = ~(0xfff);
	#else
	head->cant_use_aperture = head->agp_info.cant_use_aperture;
	head->page_mask = head->agp_info.page_mask;
	#endif

	return head;
	}

	/** Calls agp_allocate_memory() */
	DRM_AGP_MEM drm_agp_allocate_memory(struct agp_bridge_data bridge, size_t pages, u32 type)
	{
	return agp_allocate_memory(bridge, pages, type);
	}

	/** Calls agp_free_memory() */
	int drm_agp_free_memory(DRM_AGP_MEM *handle)
	{
	if (!handle)
	return 0;
	agp_free_memory(handle);
	return 1;
	}

	/** Calls agp_bind_memory() */
	int drm_agp_bind_memory(DRM_AGP_MEM *handle, off_t start)
	{
	if (!handle)
	return -EINVAL;
	return agp_bind_memory(handle, start);
	}

	/** Calls agp_unbind_memory() */
	int drm_agp_unbind_memory(DRM_AGP_MEM *handle)
	{
	if (!handle)
	return -EINVAL;
	return agp_unbind_memory(handle);
	}

	#endif /* __OS_HAS_AGP */