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backend.c

/*
 * 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/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 102
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.
 *
 */
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.
 *
 *    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 = num_physpages >> (20 - PAGE_SHIFT);
#else
      memory = num_physpages << (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) {
            void *addr = bridge->driver->agp_alloc_page(bridge);

            if (!addr) {
                  printk(KERN_ERR PFX "unable to get memory for scratch page.\n");
                  return -ENOMEM;
            }
            flush_agp_mappings();

            bridge->scratch_page_real = virt_to_gart(addr);
            bridge->scratch_page =
                bridge->driver->mask_memory(bridge, bridge->scratch_page_real, 0);
      }

      size_value = bridge->driver->fetch_size();
      if (size_value == 0) {
            printk(KERN_ERR PFX "unable to determine aperture size.\n");
            rc = -EINVAL;
            goto err_out;
      }
      if (bridge->driver->create_gatt_table(bridge)) {
            printk(KERN_ERR PFX
                "unable to get memory for graphics translation table.\n");
            rc = -ENOMEM;
            goto err_out;
      }
      got_gatt = 1;

      bridge->key_list = vmalloc(PAGE_SIZE * 4);
      if (bridge->key_list == NULL) {
            printk(KERN_ERR PFX "error allocating memory for key lists.\n");
            rc = -ENOMEM;
            goto err_out;
      }
      got_keylist = 1;

      /* FIXME vmalloc'd memory not guaranteed contiguous */
      memset(bridge->key_list, 0, PAGE_SIZE * 4);

      if (bridge->driver->configure()) {
            printk(KERN_ERR PFX "error configuring host chipset.\n");
            rc = -EINVAL;
            goto err_out;
      }

      return 0;

err_out:
      if (bridge->driver->needs_scratch_page) {
            bridge->driver->agp_destroy_page(gart_to_virt(bridge->scratch_page_real),
                                     AGP_PAGE_DESTROY_UNMAP);
            flush_agp_mappings();
            bridge->driver->agp_destroy_page(gart_to_virt(bridge->scratch_page_real),
                                     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) {
            bridge->driver->agp_destroy_page(gart_to_virt(bridge->scratch_page_real),
                                     AGP_PAGE_DESTROY_UNMAP);
            flush_agp_mappings();
            bridge->driver->agp_destroy_page(gart_to_virt(bridge->scratch_page_real),
                                     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(sizeof(*bridge), GFP_KERNEL);
      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)
            return -ENODEV;

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

      /* Grab reference on the chipset driver. */
      if (!try_module_get(bridge->driver->owner)) {
            printk (KERN_INFO PFX "Couldn't lock chipset driver.\n");
            return -EINVAL;
      }

      error = agp_backend_initialize(bridge);
      if (error) {
            printk (KERN_INFO PFX "agp_backend_initialize() failed.\n");
            goto err_out;
      }

      if (list_empty(&agp_bridges)) {
            error = agp_frontend_initialize();
            if (error) {
                  printk (KERN_INFO PFX "agp_frontend_initialize() failed.\n");
                  goto frontend_err;
            }

            printk(KERN_INFO PFX "AGP aperture is %dM @ 0x%lx\n",
                  bridge->driver->fetch_size(), bridge->gart_bus_addr);

      }

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

frontend_err:
      agp_backend_cleanup(bridge);
err_out:
      module_put(bridge->driver->owner);
      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);
      if (list_empty(&agp_bridges))
            agp_frontend_cleanup();
      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 <davej@codemonkey.org.uk>");
MODULE_DESCRIPTION("AGP GART driver");
MODULE_LICENSE("GPL and additional rights");
MODULE_ALIAS_MISCDEV(AGPGART_MINOR);

module_init(agp_init);
module_exit(agp_exit);


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