/*
 * AGPGART driver backend routines.
 * 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, DAVE JONES, 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/module.h>
#include <linux/pci.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/pagemap.h>
#include <linux/miscdevice.h>
#include <linux/pm.h>
#include <linux/agp_backend.h>
#include <linux/agpgart.h>
#include <linux/vmalloc.h>
#include <asm/io.h>
#include "agp.h"

/* Due to XFree86 brain-damage, we can't go to 1.0 until they
 * fix some real stupidity. It's only by chance we can bump
 * past 0.99 at all due to some boolean logic error. */
#define AGPGART_VERSION_MAJOR 0
#define AGPGART_VERSION_MINOR 103
static const struct agp_version agp_current_version =
{
        .major = AGPGART_VERSION_MAJOR,
        .minor = AGPGART_VERSION_MINOR,
};

struct agp_bridge_data *(*agp_find_bridge)(struct pci_dev *) =
        &agp_generic_find_bridge;

struct agp_bridge_data *agp_bridge;
LIST_HEAD(agp_bridges);
EXPORT_SYMBOL(agp_bridge);
EXPORT_SYMBOL(agp_bridges);
EXPORT_SYMBOL(agp_find_bridge);

/**
 *      agp_backend_acquire  -  attempt to acquire an agp backend.
 *      @pdev: the PCI device
 *
 */
struct agp_bridge_data *agp_backend_acquire(struct pci_dev *pdev)
{
        struct agp_bridge_data *bridge;

        bridge = agp_find_bridge(pdev);

        if (!bridge)
                return NULL;

        if (atomic_read(&bridge->agp_in_use))
                return NULL;
        atomic_inc(&bridge->agp_in_use);
        return bridge;
}
EXPORT_SYMBOL(agp_backend_acquire);


/**
 *      agp_backend_release  -  release the lock on the agp backend.
 *      @bridge: the AGP backend to release
 *
 *      The caller must insure that the graphics aperture translation table
 *      is read for use by another entity.
 *
 *      (Ensure that all memory it bound is unbound.)
 */
void agp_backend_release(struct agp_bridge_data *bridge)
{

        if (bridge)
                atomic_dec(&bridge->agp_in_use);
}
EXPORT_SYMBOL(agp_backend_release);


static const struct { int mem, agp; } maxes_table[] = {
        {0, 0},
        {32, 4},
        {64, 28},
        {128, 96},
        {256, 204},
        {512, 440},
        {1024, 942},
        {2048, 1920},
        {4096, 3932}
};

static int agp_find_max(void)
{
        long memory, index, result;

#if PAGE_SHIFT < 20
        memory = totalram_pages() >> (20 - PAGE_SHIFT);
#else
        memory = totalram_pages() << (PAGE_SHIFT - 20);
#endif
        index = 1;

        while ((memory > maxes_table[index].mem) && (index < 8))
                index++;

        result = maxes_table[index - 1].agp +
           ( (memory - maxes_table[index - 1].mem)  *
             (maxes_table[index].agp - maxes_table[index - 1].agp)) /
           (maxes_table[index].mem - maxes_table[index - 1].mem);

        result = result << (20 - PAGE_SHIFT);
        return result;
}


static int agp_backend_initialize(struct agp_bridge_data *bridge)
{
        int size_value, rc, got_gatt=0, got_keylist=0;

        bridge->max_memory_agp = agp_find_max();
        bridge->version = &agp_current_version;

        if (bridge->driver->needs_scratch_page) {
                struct page *page = bridge->driver->agp_alloc_page(bridge);

                if (!page) {
                        dev_err(&bridge->dev->dev,
                                "can't get memory for scratch page\n");
                        return -ENOMEM;
                }

                bridge->scratch_page_page = page;
                bridge->scratch_page_dma = page_to_phys(page);

                bridge->scratch_page = bridge->driver->mask_memory(bridge,
                                                   bridge->scratch_page_dma, 0);
        }

        size_value = bridge->driver->fetch_size();
        if (size_value == 0) {
                dev_err(&bridge->dev->dev, "can't determine aperture size\n");
                rc = -EINVAL;
                goto err_out;
        }
        if (bridge->driver->create_gatt_table(bridge)) {
                dev_err(&bridge->dev->dev,
                        "can't get memory for graphics translation table\n");
                rc = -ENOMEM;
                goto err_out;
        }
        got_gatt = 1;

        bridge->key_list = vzalloc(PAGE_SIZE * 4);
        if (bridge->key_list == NULL) {
                dev_err(&bridge->dev->dev,
                        "can't allocate memory for key lists\n");
                rc = -ENOMEM;
                goto err_out;
        }
        got_keylist = 1;

        /* FIXME vmalloc'd memory not guaranteed contiguous */

        if (bridge->driver->configure()) {
                dev_err(&bridge->dev->dev, "error configuring host chipset\n");
                rc = -EINVAL;
                goto err_out;
        }
        INIT_LIST_HEAD(&bridge->mapped_list);
        spin_lock_init(&bridge->mapped_lock);

        return 0;

err_out:
        if (bridge->driver->needs_scratch_page) {
                struct page *page = bridge->scratch_page_page;

                bridge->driver->agp_destroy_page(page, AGP_PAGE_DESTROY_UNMAP);
                bridge->driver->agp_destroy_page(page, AGP_PAGE_DESTROY_FREE);
        }
        if (got_gatt)
                bridge->driver->free_gatt_table(bridge);
        if (got_keylist) {
                vfree(bridge->key_list);
                bridge->key_list = NULL;
        }
        return rc;
}

/* cannot be __exit b/c as it could be called from __init code */
static void agp_backend_cleanup(struct agp_bridge_data *bridge)
{
        if (bridge->driver->cleanup)
                bridge->driver->cleanup();
        if (bridge->driver->free_gatt_table)
                bridge->driver->free_gatt_table(bridge);

        vfree(bridge->key_list);
        bridge->key_list = NULL;

        if (bridge->driver->agp_destroy_page &&
            bridge->driver->needs_scratch_page) {
                struct page *page = bridge->scratch_page_page;

                bridge->driver->agp_destroy_page(page, AGP_PAGE_DESTROY_UNMAP);
                bridge->driver->agp_destroy_page(page, AGP_PAGE_DESTROY_FREE);
        }
}

/* When we remove the global variable agp_bridge from all drivers
 * then agp_alloc_bridge and agp_generic_find_bridge need to be updated
 */

struct agp_bridge_data *agp_alloc_bridge(void)
{
        struct agp_bridge_data *bridge;

        bridge = kzalloc_obj(*bridge);
        if (!bridge)
                return NULL;

        atomic_set(&bridge->agp_in_use, 0);
        atomic_set(&bridge->current_memory_agp, 0);

        if (list_empty(&agp_bridges))
                agp_bridge = bridge;

        return bridge;
}
EXPORT_SYMBOL(agp_alloc_bridge);


void agp_put_bridge(struct agp_bridge_data *bridge)
{
        kfree(bridge);

        if (list_empty(&agp_bridges))
                agp_bridge = NULL;
}
EXPORT_SYMBOL(agp_put_bridge);


int agp_add_bridge(struct agp_bridge_data *bridge)
{
        int error;

        if (agp_off) {
                error = -ENODEV;
                goto err_put_bridge;
        }

        if (!bridge->dev) {
                printk (KERN_DEBUG PFX "Erk, registering with no pci_dev!\n");
                error = -EINVAL;
                goto err_put_bridge;
        }

        /* Grab reference on the chipset driver. */
        if (!try_module_get(bridge->driver->owner)) {
                dev_info(&bridge->dev->dev, "can't lock chipset driver\n");
                error = -EINVAL;
                goto err_put_bridge;
        }

        error = agp_backend_initialize(bridge);
        if (error) {
                dev_info(&bridge->dev->dev,
                         "agp_backend_initialize() failed\n");
                goto err_out;
        }

        if (list_empty(&agp_bridges)) {
                dev_info(&bridge->dev->dev, "AGP aperture is %dM @ 0x%lx\n",
                         bridge->driver->fetch_size(), bridge->gart_bus_addr);

        }

        list_add(&bridge->list, &agp_bridges);
        return 0;

err_out:
        module_put(bridge->driver->owner);
err_put_bridge:
        agp_put_bridge(bridge);
        return error;
}
EXPORT_SYMBOL_GPL(agp_add_bridge);


void agp_remove_bridge(struct agp_bridge_data *bridge)
{
        agp_backend_cleanup(bridge);
        list_del(&bridge->list);
        module_put(bridge->driver->owner);
}
EXPORT_SYMBOL_GPL(agp_remove_bridge);

int agp_off;
int agp_try_unsupported_boot;
EXPORT_SYMBOL(agp_off);
EXPORT_SYMBOL(agp_try_unsupported_boot);

static int __init agp_init(void)
{
        if (!agp_off)
                printk(KERN_INFO "Linux agpgart interface v%d.%d\n",
                        AGPGART_VERSION_MAJOR, AGPGART_VERSION_MINOR);
        return 0;
}

static void __exit agp_exit(void)
{
}

#ifndef MODULE
static __init int agp_setup(char *s)
{
        if (!strcmp(s,"off"))
                agp_off = 1;
        if (!strcmp(s,"try_unsupported"))
                agp_try_unsupported_boot = 1;
        return 1;
}
__setup("agp=", agp_setup);
#endif

MODULE_AUTHOR("Dave Jones, Jeff Hartmann");
MODULE_DESCRIPTION("AGP GART driver");
MODULE_LICENSE("GPL and additional rights");
MODULE_ALIAS_MISCDEV(AGPGART_MINOR);

module_init(agp_init);
module_exit(agp_exit);