path: root/drivers/char/agp/generic.c

/*
 * AGPGART driver.
 * Copyright (C) 2004 Silicon Graphics, Inc.
 * Copyright (C) 2002-2005 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.
 *
 * TODO:
 * - Allocate more than order 0 pages to avoid too much linear map splitting.
 */
#include <linux/config.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/init.h>
#include <linux/pagemap.h>
#include <linux/miscdevice.h>
#include <linux/pm.h>
#include <linux/agp_backend.h>
#include <linux/vmalloc.h>
#include <linux/dma-mapping.h>
#include <linux/mm.h>
#include <asm/io.h>
#include <asm/cacheflush.h>
#include <asm/pgtable.h>
#include "agp.h"

__u32 *agp_gatt_table;
int agp_memory_reserved;

/*
 * Needed by the Nforce GART driver for the time being. Would be
 * nice to do this some other way instead of needing this export.
 */
EXPORT_SYMBOL_GPL(agp_memory_reserved);

#if defined(CONFIG_X86)
int map_page_into_agp(struct page *page)
{
	int i;
	i = change_page_attr(page, 1, PAGE_KERNEL_NOCACHE);
	global_flush_tlb();
	return i;
}
EXPORT_SYMBOL_GPL(map_page_into_agp);

int unmap_page_from_agp(struct page *page)
{
	int i;
	i = change_page_attr(page, 1, PAGE_KERNEL);
	global_flush_tlb();
	return i;
}
EXPORT_SYMBOL_GPL(unmap_page_from_agp);
#endif

/*
 * Generic routines for handling agp_memory structures -
 * They use the basic page allocation routines to do the brunt of the work.
 */

void agp_free_key(int key)
{
	if (key < 0)
		return;

	if (key < MAXKEY)
		clear_bit(key, agp_bridge->key_list);
}
EXPORT_SYMBOL(agp_free_key);


static int agp_get_key(void)
{
	int bit;

	bit = find_first_zero_bit(agp_bridge->key_list, MAXKEY);
	if (bit < MAXKEY) {
		set_bit(bit, agp_bridge->key_list);
		return bit;
	}
	return -1;
}


struct agp_memory *agp_create_memory(int scratch_pages)
{
	struct agp_memory *new;

	new = kmalloc(sizeof(struct agp_memory), GFP_KERNEL);

	if (new == NULL)
		return NULL;

	memset(new, 0, sizeof(struct agp_memory));
	new->key = agp_get_key();

	if (new->key < 0) {
		kfree(new);
		return NULL;
	}
	new->memory = vmalloc(PAGE_SIZE * scratch_pages);

	if (new->memory == NULL) {
		agp_free_key(new->key);
		kfree(new);
		return NULL;
	}
	new->num_scratch_pages = scratch_pages;
	return new;
}
EXPORT_SYMBOL(agp_create_memory);

/**
 *	agp_free_memory - free memory associated with an agp_memory pointer.
 *
 *	@curr:		agp_memory pointer to be freed.
 *
 *	It is the only function that can be called when the backend is not owned
 *	by the caller.  (So it can free memory on client death.)
 */
void