drivers/gpu/drm/drm_agpsupport.c - kernel/quantenna - Git at Google

 /**
  * \file drm_agpsupport.c
  * 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 <drm/drmP.h>
 #include <linux/module.h>
 #include <linux/slab.h>
 #include "drm_legacy.h"

 #include <asm/agp.h>

 /**
  * Get AGP information.
  *
  * \param inode device inode.
  * \param file_priv DRM file private.
  * \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 drm_device *dev, struct drm_agp_info *info)
 {
 	struct agp_kern_info *kern;

 	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;

 	return 0;
 }

 EXPORT_SYMBOL(drm_agp_info);

 int drm_agp_info_ioctl(struct drm_device *dev, void *data,
 		       struct drm_file *file_priv)
 {
 	struct drm_agp_info *info = data;
 	int err;

 	err = drm_agp_info(dev, info);
 	if (err)
 		return err;

 	return 0;
 }

 /**
  * Acquire the AGP device.
  *
  * \param dev DRM device that is to acquire AGP.
  * \return zero on success or a negative number on failure.
  *
  * Verifies the AGP device hasn't been acquired before and calls
  * \c agp_backend_acquire.
  */
 int drm_agp_acquire(struct drm_device * 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;
 }

 EXPORT_SYMBOL(drm_agp_acquire);

 /**
  * Acquire the AGP device (ioctl).
  *
  * \param inode device inode.
  * \param file_priv DRM file private.
  * \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
  * \c agp_backend_acquire.
  */
 int drm_agp_acquire_ioctl(struct drm_device *dev, void *data,
 			  struct drm_file *file_priv)
 {
 	return drm_agp_acquire((struct drm_device *) file_priv->minor->dev);
 }

 /**
  * Release the AGP device.
  *
  * \param dev DRM device that is to release AGP.
  * \return zero on success or a negative number on failure.
  *
  * Verifies the AGP device has been acquired and calls \c agp_backend_release.
  */
 int drm_agp_release(struct drm_device * dev)
 {
 	if (!dev->agp || !dev->agp->acquired)
 		return -EINVAL;
 	agp_backend_release(dev->agp->bridge);
 	dev->agp->acquired = 0;
 	return 0;
 }
 EXPORT_SYMBOL(drm_agp_release);

 int drm_agp_release_ioctl(struct drm_device *dev, void *data,
 			  struct drm_file *file_priv)
 {
 	return drm_agp_release(dev);
 }

 /**
  * Enable the AGP bus.
  *
  * \param dev DRM device that has previously acquired AGP.
  * \param mode Requested AGP mode.
  * \return zero on success or a negative number on failure.
  *
  * Verifies the AGP device has been acquired but not enabled, and calls
  * \c agp_enable.
  */
 int drm_agp_enable(struct drm_device * dev, struct drm_agp_mode mode)
 {
 	if (!dev->agp || !dev->agp->acquired)
 		return -EINVAL;

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

 EXPORT_SYMBOL(drm_agp_enable);

 int drm_agp_enable_ioctl(struct drm_device *dev, void *data,
 			 struct drm_file *file_priv)
 {
 	struct drm_agp_mode *mode = data;

 	return drm_agp_enable(dev, *mode);
 }

 /**
  * Allocate AGP memory.
  *
  * \param inode device inode.
  * \param file_priv file private 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 agp_allocate_memory() and creates a drm_agp_mem entry for it.
  */
 int drm_agp_alloc(struct drm_device *dev, struct drm_agp_buffer *request)
 {
 	struct drm_agp_mem *entry;
 	struct agp_memory *memory;
 	unsigned long pages;
 	u32 type;

 	if (!dev->agp || !dev->agp->acquired)
 		return -EINVAL;
 	if (!(entry = kzalloc(sizeof(*entry), GFP_KERNEL)))
 		return -ENOMEM;

 	pages = (request->size + PAGE_SIZE - 1) / PAGE_SIZE;
 	type = (u32) request->type;
 	if (!(memory = agp_allocate_memory(dev->agp->bridge, pages, type))) {
 		kfree(entry);
 		return -ENOMEM;
 	}

 	entry->handle = (unsigned long)memory->key + 1;
 	entry->memory = memory;
 	entry->bound = 0;
 	entry->pages = pages;
 	list_add(&entry->head, &dev->agp->memory);

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

 	return 0;
 }
 EXPORT_SYMBOL(drm_agp_alloc);


 int drm_agp_alloc_ioctl(struct drm_device *dev, void *data,
 			struct drm_file *file_priv)
 {
 	struct drm_agp_buffer *request = data;

 	return drm_agp_alloc(dev, request);
 }

 /**
  * 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 struct drm_agp_mem *drm_agp_lookup_entry(struct drm_device * dev,
 					   unsigned long handle)
 {
 	struct drm_agp_mem *entry;

 	list_for_each_entry(entry, &dev->agp->memory, head) {
 		if (entry->handle == handle)
 			return entry;
 	}
 	return NULL;
 }

 /**
  * Unbind AGP memory from the GATT (ioctl).
  *
  * \param inode device inode.
  * \param file_priv DRM file private.
  * \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 drm_device *dev, struct drm_agp_binding *request)
 {
 	struct drm_agp_mem *entry;
 	int ret;

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


 int drm_agp_unbind_ioctl(struct drm_device *dev, void *data,
 			 struct drm_file *file_priv)
 {
 	struct drm_agp_binding *request = data;

 	return drm_agp_unbind(dev, request);
 }

 /**
  * Bind AGP memory into the GATT (ioctl)
  *
  * \param inode device inode.
  * \param file_priv DRM file private.
  * \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 drm_device *dev, struct drm_agp_binding *request)
 {
 	struct drm_agp_mem *entry;
 	int retcode;
 	int page;

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


 int drm_agp_bind_ioctl(struct drm_device *dev, void *data,
 		       struct drm_file *file_priv)
 {
 	struct drm_agp_binding *request = data;

 	return drm_agp_bind(dev, request);
 }

 /**
  * Free AGP memory (ioctl).
  *
  * \param inode device inode.
  * \param file_priv DRM file private.
  * \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 drm_device *dev, struct drm_agp_buffer *request)
 {
 	struct drm_agp_mem *entry;

 	if (!dev->agp || !dev->agp->acquired)
 		return -EINVAL;
 	if (!(entry = drm_agp_lookup_entry(dev, request->handle)))
 		return -EINVAL;
 	if (entry->bound)
 		drm_unbind_agp(entry->memory);

 	list_del(&entry->head);

 	drm_free_agp(entry->memory, entry->pages);
 	kfree(entry);
 	return 0;
 }
 EXPORT_SYMBOL(drm_agp_free);


 int drm_agp_free_ioctl(struct drm_device *dev, void *data,
 		       struct drm_file *file_priv)
 {
 	struct drm_agp_buffer *request = data;

 	return drm_agp_free(dev, request);
 }

 /**
  * Initialize the AGP resources.
  *
  * \return pointer to a drm_agp_head structure.
  *
  * Gets the drm_agp_t structure which is made available by the agpgart module
  * via the inter_module_* functions. Creates and initializes a drm_agp_head
  * structure.
  *
  * Note that final cleanup of the kmalloced structure is directly done in
  * drm_pci_agp_destroy.
  */
 struct drm_agp_head *drm_agp_init(struct drm_device *dev)
 {
 	struct drm_agp_head *head = NULL;

 	if (!(head = kzalloc(sizeof(*head), GFP_KERNEL)))
 		return NULL;
 	head->bridge = agp_find_bridge(dev->pdev);
 	if (!head->bridge) {
 		if (!(head->bridge = agp_backend_acquire(dev->pdev))) {
 			kfree(head);
 			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) {
 		kfree(head);
 		return NULL;
 	}
 	INIT_LIST_HEAD(&head->memory);
 	head->cant_use_aperture = head->agp_info.cant_use_aperture;
 	head->page_mask = head->agp_info.page_mask;
 	head->base = head->agp_info.aper_base;
 	return head;
 }

 /**
  * drm_legacy_agp_clear - Clear AGP resource list
  * @dev: DRM device
  *
  * Iterate over all AGP resources and remove them. But keep the AGP head
  * intact so it can still be used. It is safe to call this if AGP is disabled or
  * was already removed.
  *
  * If DRIVER_MODESET is active, nothing is done to protect the modesetting
  * resources from getting destroyed. Drivers are responsible of cleaning them up
  * during device shutdown.
  */
 void drm_legacy_agp_clear(struct drm_device *dev)
 {
 	struct drm_agp_mem *entry, *tempe;

 	if (!dev->agp)
 		return;
 	if (drm_core_check_feature(dev, DRIVER_MODESET))
 		return;

 	list_for_each_entry_safe(entry, tempe, &dev->agp->memory, head) {
 		if (entry->bound)
 			drm_unbind_agp(entry->memory);
 		drm_free_agp(entry->memory, entry->pages);
 		kfree(entry);
 	}
 	INIT_LIST_HEAD(&dev->agp->memory);

 	if (dev->agp->acquired)
 		drm_agp_release(dev);

 	dev->agp->acquired = 0;
 	dev->agp->enabled = 0;
 }

 /**
  * Binds a collection of pages into AGP memory at the given offset, returning
  * the AGP memory structure containing them.
  *
  * No reference is held on the pages during this time -- it is up to the
  * caller to handle that.
  */
 struct agp_memory *
 drm_agp_bind_pages(struct drm_device *dev,
 		   struct page **pages,
 		   unsigned long num_pages,
 		   uint32_t gtt_offset,
 		   u32 type)
 {
 	struct agp_memory *mem;
 	int ret, i;

 	DRM_DEBUG("\n");

 	mem = agp_allocate_memory(dev->agp->bridge, num_pages,
 				      type);
 	if (mem == NULL) {
 		DRM_ERROR("Failed to allocate memory for %ld pages\n",
 			  num_pages);
 		return NULL;
 	}

 	for (i = 0; i < num_pages; i++)
 		mem->pages[i] = pages[i];
 	mem->page_count = num_pages;

 	mem->is_flushed = true;
 	ret = agp_bind_memory(mem, gtt_offset / PAGE_SIZE);
 	if (ret != 0) {
 		DRM_ERROR("Failed to bind AGP memory: %d\n", ret);
 		agp_free_memory(mem);
 		return NULL;
 	}

 	return mem;
 }
 EXPORT_SYMBOL(drm_agp_bind_pages);
	/**
	* \file drm_agpsupport.c
	* 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 <drm/drmP.h>
	#include <linux/module.h>
	#include <linux/slab.h>
	#include "drm_legacy.h"

	#include <asm/agp.h>

	/**
	* Get AGP information.
	*
	* \param inode device inode.
	* \param file_priv DRM file private.
	* \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 drm_device dev, struct drm_agp_info info)
	{
	struct agp_kern_info *kern;

	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;

	return 0;
	}

	EXPORT_SYMBOL(drm_agp_info);

	int drm_agp_info_ioctl(struct drm_device dev, void data,
	struct drm_file *file_priv)
	{
	struct drm_agp_info *info = data;
	int err;

	err = drm_agp_info(dev, info);
	if (err)
	return err;

	return 0;
	}

	/**
	* Acquire the AGP device.
	*
	* \param dev DRM device that is to acquire AGP.
	* \return zero on success or a negative number on failure.
	*
	* Verifies the AGP device hasn't been acquired before and calls
	* \c agp_backend_acquire.
	*/
	int drm_agp_acquire(struct drm_device * 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;
	}

	EXPORT_SYMBOL(drm_agp_acquire);

	/**
	* Acquire the AGP device (ioctl).
	*
	* \param inode device inode.
	* \param file_priv DRM file private.
	* \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
	* \c agp_backend_acquire.
	*/
	int drm_agp_acquire_ioctl(struct drm_device dev, void data,
	struct drm_file *file_priv)
	{
	return drm_agp_acquire((struct drm_device *) file_priv->minor->dev);
	}

	/**
	* Release the AGP device.
	*
	* \param dev DRM device that is to release AGP.
	* \return zero on success or a negative number on failure.
	*
	* Verifies the AGP device has been acquired and calls \c agp_backend_release.
	*/
	int drm_agp_release(struct drm_device * dev)
	{
	if (!dev->agp \|\| !dev->agp->acquired)
	return -EINVAL;
	agp_backend_release(dev->agp->bridge);
	dev->agp->acquired = 0;
	return 0;
	}
	EXPORT_SYMBOL(drm_agp_release);

	int drm_agp_release_ioctl(struct drm_device dev, void data,
	struct drm_file *file_priv)
	{
	return drm_agp_release(dev);
	}

	/**
	* Enable the AGP bus.
	*
	* \param dev DRM device that has previously acquired AGP.
	* \param mode Requested AGP mode.
	* \return zero on success or a negative number on failure.
	*
	* Verifies the AGP device has been acquired but not enabled, and calls
	* \c agp_enable.
	*/
	int drm_agp_enable(struct drm_device * dev, struct drm_agp_mode mode)
	{
	if (!dev->agp \|\| !dev->agp->acquired)
	return -EINVAL;

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

	EXPORT_SYMBOL(drm_agp_enable);

	int drm_agp_enable_ioctl(struct drm_device dev, void data,
	struct drm_file *file_priv)
	{
	struct drm_agp_mode *mode = data;

	return drm_agp_enable(dev, *mode);
	}

	/**
	* Allocate AGP memory.
	*
	* \param inode device inode.
	* \param file_priv file private 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 agp_allocate_memory() and creates a drm_agp_mem entry for it.
	*/
	int drm_agp_alloc(struct drm_device dev, struct drm_agp_buffer request)
	{
	struct drm_agp_mem *entry;
	struct agp_memory *memory;
	unsigned long pages;
	u32 type;

	if (!dev->agp \|\| !dev->agp->acquired)
	return -EINVAL;
	if (!(entry = kzalloc(sizeof(*entry), GFP_KERNEL)))
	return -ENOMEM;

	pages = (request->size + PAGE_SIZE - 1) / PAGE_SIZE;
	type = (u32) request->type;
	if (!(memory = agp_allocate_memory(dev->agp->bridge, pages, type))) {
	kfree(entry);
	return -ENOMEM;
	}

	entry->handle = (unsigned long)memory->key + 1;
	entry->memory = memory;
	entry->bound = 0;
	entry->pages = pages;
	list_add(&entry->head, &dev->agp->memory);

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

	return 0;
	}
	EXPORT_SYMBOL(drm_agp_alloc);


	int drm_agp_alloc_ioctl(struct drm_device dev, void data,
	struct drm_file *file_priv)
	{
	struct drm_agp_buffer *request = data;

	return drm_agp_alloc(dev, request);
	}

	/**
	* 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 struct drm_agp_mem drm_agp_lookup_entry(struct drm_device dev,
	unsigned long handle)
	{
	struct drm_agp_mem *entry;

	list_for_each_entry(entry, &dev->agp->memory, head) {
	if (entry->handle == handle)
	return entry;
	}
	return NULL;
	}

	/**
	* Unbind AGP memory from the GATT (ioctl).
	*
	* \param inode device inode.
	* \param file_priv DRM file private.
	* \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 drm_device dev, struct drm_agp_binding request)
	{
	struct drm_agp_mem *entry;
	int ret;

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


	int drm_agp_unbind_ioctl(struct drm_device dev, void data,
	struct drm_file *file_priv)
	{
	struct drm_agp_binding *request = data;

	return drm_agp_unbind(dev, request);
	}

	/**
	* Bind AGP memory into the GATT (ioctl)
	*
	* \param inode device inode.
	* \param file_priv DRM file private.
	* \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 drm_device dev, struct drm_agp_binding request)
	{
	struct drm_agp_mem *entry;
	int retcode;
	int page;

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


	int drm_agp_bind_ioctl(struct drm_device dev, void data,
	struct drm_file *file_priv)
	{
	struct drm_agp_binding *request = data;

	return drm_agp_bind(dev, request);
	}

	/**
	* Free AGP memory (ioctl).
	*
	* \param inode device inode.
	* \param file_priv DRM file private.
	* \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 drm_device dev, struct drm_agp_buffer request)
	{
	struct drm_agp_mem *entry;

	if (!dev->agp \|\| !dev->agp->acquired)
	return -EINVAL;
	if (!(entry = drm_agp_lookup_entry(dev, request->handle)))
	return -EINVAL;
	if (entry->bound)
	drm_unbind_agp(entry->memory);

	list_del(&entry->head);

	drm_free_agp(entry->memory, entry->pages);
	kfree(entry);
	return 0;
	}
	EXPORT_SYMBOL(drm_agp_free);



	int drm_agp_free_ioctl(struct drm_device dev, void data,
	struct drm_file *file_priv)
	{
	struct drm_agp_buffer *request = data;

	return drm_agp_free(dev, request);
	}

	/**
	* Initialize the AGP resources.
	*
	* \return pointer to a drm_agp_head structure.
	*
	* Gets the drm_agp_t structure which is made available by the agpgart module
	* via the inter_module_* functions. Creates and initializes a drm_agp_head
	* structure.
	*
	* Note that final cleanup of the kmalloced structure is directly done in
	* drm_pci_agp_destroy.
	*/
	struct drm_agp_head drm_agp_init(struct drm_device dev)
	{
	struct drm_agp_head *head = NULL;

	if (!(head = kzalloc(sizeof(*head), GFP_KERNEL)))
	return NULL;
	head->bridge = agp_find_bridge(dev->pdev);
	if (!head->bridge) {
	if (!(head->bridge = agp_backend_acquire(dev->pdev))) {
	kfree(head);
	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) {
	kfree(head);
	return NULL;
	}
	INIT_LIST_HEAD(&head->memory);
	head->cant_use_aperture = head->agp_info.cant_use_aperture;
	head->page_mask = head->agp_info.page_mask;
	head->base = head->agp_info.aper_base;
	return head;
	}

	/**
	* drm_legacy_agp_clear - Clear AGP resource list
	* @dev: DRM device
	*
	* Iterate over all AGP resources and remove them. But keep the AGP head
	* intact so it can still be used. It is safe to call this if AGP is disabled or
	* was already removed.
	*
	* If DRIVER_MODESET is active, nothing is done to protect the modesetting
	* resources from getting destroyed. Drivers are responsible of cleaning them up
	* during device shutdown.
	*/
	void drm_legacy_agp_clear(struct drm_device *dev)
	{
	struct drm_agp_mem entry, tempe;

	if (!dev->agp)
	return;
	if (drm_core_check_feature(dev, DRIVER_MODESET))
	return;

	list_for_each_entry_safe(entry, tempe, &dev->agp->memory, head) {
	if (entry->bound)
	drm_unbind_agp(entry->memory);
	drm_free_agp(entry->memory, entry->pages);
	kfree(entry);
	}
	INIT_LIST_HEAD(&dev->agp->memory);

	if (dev->agp->acquired)
	drm_agp_release(dev);

	dev->agp->acquired = 0;
	dev->agp->enabled = 0;
	}

	/**
	* Binds a collection of pages into AGP memory at the given offset, returning
	* the AGP memory structure containing them.
	*
	* No reference is held on the pages during this time -- it is up to the
	* caller to handle that.
	*/
	struct agp_memory *
	drm_agp_bind_pages(struct drm_device *dev,
	struct page **pages,
	unsigned long num_pages,
	uint32_t gtt_offset,
	u32 type)
	{
	struct agp_memory *mem;
	int ret, i;

	DRM_DEBUG("\n");

	mem = agp_allocate_memory(dev->agp->bridge, num_pages,
	type);
	if (mem == NULL) {
	DRM_ERROR("Failed to allocate memory for %ld pages\n",
	num_pages);
	return NULL;
	}

	for (i = 0; i < num_pages; i++)
	mem->pages[i] = pages[i];
	mem->page_count = num_pages;

	mem->is_flushed = true;
	ret = agp_bind_memory(mem, gtt_offset / PAGE_SIZE);
	if (ret != 0) {
	DRM_ERROR("Failed to bind AGP memory: %d\n", ret);
	agp_free_memory(mem);
	return NULL;
	}

	return mem;
	}
	EXPORT_SYMBOL(drm_agp_bind_pages);