/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2000 Doug Rabson
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/cdefs.h>
#include "opt_agp.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/malloc.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <sys/bus.h>
#include <sys/conf.h>
#include <sys/ioccom.h>
#include <sys/agpio.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/rwlock.h>

#include <dev/agp/agppriv.h>
#include <dev/agp/agpvar.h>
#include <dev/agp/agpreg.h>
#include <dev/pci/pcivar.h>
#include <dev/pci/pcireg.h>

#include <vm/vm.h>
#include <vm/vm_extern.h>
#include <vm/vm_kern.h>
#include <vm/vm_param.h>
#include <vm/vm_object.h>
#include <vm/vm_page.h>
#include <vm/vm_pageout.h>
#include <vm/vm_radix.h>
#include <vm/pmap.h>

#include <machine/bus.h>
#include <machine/resource.h>
#include <sys/rman.h>

MODULE_VERSION(agp, 1);

MALLOC_DEFINE(M_AGP, "agp", "AGP data structures");

                                /* agp_drv.c */
static d_open_t agp_open;
static d_close_t agp_close;
static d_ioctl_t agp_ioctl;
static d_mmap_t agp_mmap;

static struct cdevsw agp_cdevsw = {
        .d_version =    D_VERSION,
        .d_flags =      D_NEEDGIANT,
        .d_open =       agp_open,
        .d_close =      agp_close,
        .d_ioctl =      agp_ioctl,
        .d_mmap =       agp_mmap,
        .d_name =       "agp",
};

static devclass_t agp_devclass;

/* Helper functions for implementing chipset mini drivers. */

u_int8_t
agp_find_caps(device_t dev)
{
        int capreg;

        if (pci_find_cap(dev, PCIY_AGP, &capreg) != 0)
                capreg = 0;
        return (capreg);
}

/*
 * Find an AGP display device (if any).
 */
static device_t
agp_find_display(void)
{
        devclass_t pci = devclass_find("pci");
        device_t bus, dev = 0;
        device_t *kids;
        int busnum, numkids, i;

        for (busnum = 0; busnum < devclass_get_maxunit(pci); busnum++) {
                bus = devclass_get_device(pci, busnum);
                if (!bus)
                        continue;
                if (device_get_children(bus, &kids, &numkids) != 0)
                        continue;
                for (i = 0; i < numkids; i++) {
                        dev = kids[i];
                        if (pci_get_class(dev) == PCIC_DISPLAY
                            && pci_get_subclass(dev) == PCIS_DISPLAY_VGA)
                                if (agp_find_caps(dev)) {
                                        free(kids, M_TEMP);
                                        return dev;
                                }
                                        
                }
                free(kids, M_TEMP);
        }

        return 0;
}

struct agp_gatt *
agp_alloc_gatt(device_t dev)
{
        u_int32_t apsize = AGP_GET_APERTURE(dev);
        u_int32_t entries = apsize >> AGP_PAGE_SHIFT;
        struct agp_gatt *gatt;

        if (bootverbose)
                device_printf(dev,
                              "allocating GATT for aperture of size %dM\n",
                              apsize / (1024*1024));

        if (entries == 0) {
                device_printf(dev, "bad aperture size\n");
                return NULL;
        }

        gatt = malloc(sizeof(struct agp_gatt), M_AGP, M_NOWAIT);
        if (!gatt)
                return 0;

        gatt->ag_entries = entries;
        gatt->ag_virtual = kmem_alloc_contig(entries * sizeof(uint32_t),
            M_NOWAIT | M_ZERO, 0, ~0, PAGE_SIZE, 0, VM_MEMATTR_WRITE_COMBINING);
        if (!gatt->ag_virtual) {
                if (bootverbose)
                        device_printf(dev, "contiguous allocation failed\n");
                free(gatt, M_AGP);
                return 0;
        }
        gatt->ag_physical = vtophys((vm_offset_t) gatt->ag_virtual);

        return gatt;
}

void
agp_free_gatt(struct agp_gatt *gatt)
{
        kmem_free(gatt->ag_virtual, gatt->ag_entries * sizeof(uint32_t));
        free(gatt, M_AGP);
}

static u_int agp_max[][2] = {
        {0,     0},
        {32,    4},
        {64,    28},
        {128,   96},
        {256,   204},
        {512,   440},
        {1024,  942},
        {2048,  1920},
        {4096,  3932}
};
#define AGP_MAX_SIZE    nitems(agp_max)

/**
 * Sets the PCI resource which represents the AGP aperture.
 *
 * If not called, the default AGP aperture resource of AGP_APBASE will
 * be used.  Must be called before agp_generic_attach().
 */
void
agp_set_aperture_resource(device_t dev, int rid)
{
        struct agp_softc *sc = device_get_softc(dev);

        sc->as_aperture_rid = rid;
}

int
agp_generic_attach(device_t dev)
{
        struct make_dev_args mdargs;
        struct agp_softc *sc = device_get_softc(dev);
        int error, i, unit;
        u_int memsize;

        /*
         * Find and map the aperture, RF_SHAREABLE for DRM but not RF_ACTIVE
         * because the kernel doesn't need to map it.
         */

        if (sc->as_aperture_rid != -1) {
                if (sc->as_aperture_rid == 0)
                        sc->as_aperture_rid = AGP_APBASE;

                sc->as_aperture = bus_alloc_resource_any(dev, SYS_RES_MEMORY,
                    &sc->as_aperture_rid, RF_SHAREABLE);
                if (!sc->as_aperture)
                        return ENOMEM;
        }

        /*
         * Work out an upper bound for agp memory allocation. This
         * uses a heurisitc table from the Linux driver.
         */
        memsize = ptoa(realmem) >> 20;
        for (i = 0; i < AGP_MAX_SIZE; i++) {
                if (memsize <= agp_max[i][0])
                        break;
        }
        if (i == AGP_MAX_SIZE)
                i = AGP_MAX_SIZE - 1;
        sc->as_maxmem = agp_max[i][1] << 20U;

        /*
         * The lock is used to prevent re-entry to
         * agp_generic_bind_memory() since that function can sleep.
         */
        mtx_init(&sc->as_lock, "agp lock", NULL, MTX_DEF);

        /*
         * Initialise stuff for the userland device.
         */
        agp_devclass = devclass_find("agp");
        TAILQ_INIT(&sc->as_memory);
        sc->as_nextid = 1;

        sc->as_devalias = NULL;

        make_dev_args_init(&mdargs);
        mdargs.mda_devsw = &agp_cdevsw;
        mdargs.mda_uid = UID_ROOT;
        mdargs.mda_gid = GID_WHEEL;
        mdargs.mda_mode = 0600;
        mdargs.mda_si_drv1 = dev;
        mdargs.mda_si_drv2 = NULL;

        unit = device_get_unit(dev);
        error = make_dev_s(&mdargs, &sc->as_devnode, "agpgart%d", unit);
        if (error == 0) {
                /*
                 * Create an alias for the first device that shows up.
                 */
                if (unit == 0) {
                        (void)make_dev_alias_p(MAKEDEV_CHECKNAME,
                            &sc->as_devalias, sc->as_devnode, "agpgart");
                }
        } else {
                agp_free_res(dev);
        }

        return error;
}

void
agp_free_cdev(device_t dev)
{
        struct agp_softc *sc = device_get_softc(dev);

        destroy_dev(sc->as_devnode);
        if (sc->as_devalias != NULL)
                destroy_dev(sc->as_devalias);
}

void
agp_free_res(device_t dev)
{
        struct agp_softc *sc = device_get_softc(dev);

        if (sc->as_aperture != NULL)
                bus_release_resource(dev, SYS_RES_MEMORY, sc->as_aperture_rid,
                    sc->as_aperture);
        mtx_destroy(&sc->as_lock);
}

int
agp_generic_detach(device_t dev)
{

        agp_free_cdev(dev);
        agp_free_res(dev);
        return 0;
}

/**
 * Default AGP aperture size detection which simply returns the size of
 * the aperture's PCI resource.
 */
u_int32_t
agp_generic_get_aperture(device_t dev)
{
        struct agp_softc *sc = device_get_softc(dev);

        return rman_get_size(sc->as_aperture);
}

/**
 * Default AGP aperture size setting function, which simply doesn't allow
 * changes to resource size.
 */
int
agp_generic_set_aperture(device_t dev, u_int32_t aperture)
{
        u_int32_t current_aperture;

        current_aperture = AGP_GET_APERTURE(dev);
        if (current_aperture != aperture)
                return EINVAL;
        else
                return 0;
}

/*
 * This does the enable logic for v3, with the same topology
 * restrictions as in place for v2 -- one bus, one device on the bus.
 */
static int
agp_v3_enable(device_t dev, device_t mdev, u_int32_t mode)
{
        u_int32_t tstatus, mstatus;
        u_int32_t command;
        int rq, sba, fw, rate, arqsz, cal;

        tstatus = pci_read_config(dev, agp_find_caps(dev) + AGP_STATUS, 4);
        mstatus = pci_read_config(mdev, agp_find_caps(mdev) + AGP_STATUS, 4);

        /* Set RQ to the min of mode, tstatus and mstatus */
        rq = AGP_MODE_GET_RQ(mode);
        if (AGP_MODE_GET_RQ(tstatus) < rq)
                rq = AGP_MODE_GET_RQ(tstatus);
        if (AGP_MODE_GET_RQ(mstatus) < rq)
                rq = AGP_MODE_GET_RQ(mstatus);

        /*
         * ARQSZ - Set the value to the maximum one.
         * Don't allow the mode register to override values.
         */
        arqsz = AGP_MODE_GET_ARQSZ(mode);
        if (AGP_MODE_GET_ARQSZ(tstatus) > rq)
                rq = AGP_MODE_GET_ARQSZ(tstatus);
        if (AGP_MODE_GET_ARQSZ(mstatus) > rq)
                rq = AGP_MODE_GET_ARQSZ(mstatus);

        /* Calibration cycle - don't allow override by mode register */
        cal = AGP_MODE_GET_CAL(tstatus);
        if (AGP_MODE_GET_CAL(mstatus) < cal)
                cal = AGP_MODE_GET_CAL(mstatus);

        /* SBA must be supported for AGP v3. */
        sba = 1;

        /* Set FW if all three support it. */
        fw = (AGP_MODE_GET_FW(tstatus)
               & AGP_MODE_GET_FW(mstatus)
               & AGP_MODE_GET_FW(mode));

        /* Figure out the max rate */
        rate = (AGP_MODE_GET_RATE(tstatus)
                & AGP_MODE_GET_RATE(mstatus)
                & AGP_MODE_GET_RATE(mode));
        if (rate & AGP_MODE_V3_RATE_8x)
                rate = AGP_MODE_V3_RATE_8x;
        else
                rate = AGP_MODE_V3_RATE_4x;
        if (bootverbose)
                device_printf(dev, "Setting AGP v3 mode %d\n", rate * 4);

        pci_write_config(dev, agp_find_caps(dev) + AGP_COMMAND, 0, 4);

        /* Construct the new mode word and tell the hardware */
        command = 0;
        command = AGP_MODE_SET_RQ(0, rq);
        command = AGP_MODE_SET_ARQSZ(command, arqsz);
        command = AGP_MODE_SET_CAL(command, cal);
        command = AGP_MODE_SET_SBA(command, sba);
        command = AGP_MODE_SET_FW(command, fw);
        command = AGP_MODE_SET_RATE(command, rate);
        command = AGP_MODE_SET_MODE_3(command, 1);
        command = AGP_MODE_SET_AGP(command, 1);
        pci_write_config(dev, agp_find_caps(dev) + AGP_COMMAND, command, 4);
        pci_write_config(mdev, agp_find_caps(mdev) + AGP_COMMAND, command, 4);

        return 0;
}

static int
agp_v2_enable(device_t dev, device_t mdev, u_int32_t mode)
{
        u_int32_t tstatus, mstatus;
        u_int32_t command;
        int rq, sba, fw, rate;

        tstatus = pci_read_config(dev, agp_find_caps(dev) + AGP_STATUS, 4);
        mstatus = pci_read_config(mdev, agp_find_caps(mdev) + AGP_STATUS, 4);

        /* Set RQ to the min of mode, tstatus and mstatus */
        rq = AGP_MODE_GET_RQ(mode);
        if (AGP_MODE_GET_RQ(tstatus) < rq)
                rq = AGP_MODE_GET_RQ(tstatus);
        if (AGP_MODE_GET_RQ(mstatus) < rq)
                rq = AGP_MODE_GET_RQ(mstatus);

        /* Set SBA if all three can deal with SBA */
        sba = (AGP_MODE_GET_SBA(tstatus)
               & AGP_MODE_GET_SBA(mstatus)
               & AGP_MODE_GET_SBA(mode));

        /* Similar for FW */
        fw = (AGP_MODE_GET_FW(tstatus)
               & AGP_MODE_GET_FW(mstatus)
               & AGP_MODE_GET_FW(mode));

        /* Figure out the max rate */
        rate = (AGP_MODE_GET_RATE(tstatus)
                & AGP_MODE_GET_RATE(mstatus)
                & AGP_MODE_GET_RATE(mode));
        if (rate & AGP_MODE_V2_RATE_4x)
                rate = AGP_MODE_V2_RATE_4x;
        else if (rate & AGP_MODE_V2_RATE_2x)
                rate = AGP_MODE_V2_RATE_2x;
        else
                rate = AGP_MODE_V2_RATE_1x;
        if (bootverbose)
                device_printf(dev, "Setting AGP v2 mode %d\n", rate);

        /* Construct the new mode word and tell the hardware */
        command = 0;
        command = AGP_MODE_SET_RQ(0, rq);
        command = AGP_MODE_SET_SBA(command, sba);
        command = AGP_MODE_SET_FW(command, fw);
        command = AGP_MODE_SET_RATE(command, rate);
        command = AGP_MODE_SET_AGP(command, 1);
        pci_write_config(dev, agp_find_caps(dev) + AGP_COMMAND, command, 4);
        pci_write_config(mdev, agp_find_caps(mdev) + AGP_COMMAND, command, 4);

        return 0;
}

int
agp_generic_enable(device_t dev, u_int32_t mode)
{
        device_t mdev = agp_find_display();
        u_int32_t tstatus, mstatus;

        if (!mdev) {
                AGP_DPF("can't find display\n");
                return ENXIO;
        }

        tstatus = pci_read_config(dev, agp_find_caps(dev) + AGP_STATUS, 4);
        mstatus = pci_read_config(mdev, agp_find_caps(mdev) + AGP_STATUS, 4);

        /*
         * Check display and bridge for AGP v3 support.  AGP v3 allows
         * more variety in topology than v2, e.g. multiple AGP devices
         * attached to one bridge, or multiple AGP bridges in one
         * system.  This doesn't attempt to address those situations,
         * but should work fine for a classic single AGP slot system
         * with AGP v3.
         */
        if (AGP_MODE_GET_MODE_3(mode) &&
            AGP_MODE_GET_MODE_3(tstatus) &&
            AGP_MODE_GET_MODE_3(mstatus))
                return (agp_v3_enable(dev, mdev, mode));
        else
                return (agp_v2_enable(dev, mdev, mode));            
}

struct agp_memory *
agp_generic_alloc_memory(device_t dev, int type, vm_size_t size)
{
        struct agp_softc *sc = device_get_softc(dev);
        struct agp_memory *mem;

        if ((size & (AGP_PAGE_SIZE - 1)) != 0)
                return 0;

        if (size > sc->as_maxmem - sc->as_allocated)
                return 0;

        if (type != 0) {
                printf("agp_generic_alloc_memory: unsupported type %d\n",
                       type);
                return 0;
        }

        mem = malloc(sizeof *mem, M_AGP, M_WAITOK);
        mem->am_id = sc->as_nextid++;
        mem->am_size = size;
        mem->am_type = 0;
        mem->am_obj = vm_object_allocate(OBJT_SWAP, atop(round_page(size)));
        mem->am_physical = 0;
        mem->am_offset = 0;
        mem->am_is_bound = 0;
        TAILQ_INSERT_TAIL(&sc->as_memory, mem, am_link);
        sc->as_allocated += size;

        return mem;
}

int
agp_generic_free_memory(device_t dev, struct agp_memory *mem)
{
        struct agp_softc *sc = device_get_softc(dev);

        if (mem->am_is_bound)
                return EBUSY;

        sc->as_allocated -= mem->am_size;
        TAILQ_REMOVE(&sc->as_memory, mem, am_link);
        vm_object_deallocate(mem->am_obj);
        free(mem, M_AGP);
        return 0;
}

int
agp_generic_bind_memory(device_t dev, struct agp_memory *mem,
                        vm_offset_t offset)
{
        struct pctrie_iter pages;
        struct agp_softc *sc = device_get_softc(dev);
        vm_offset_t i, j, k;
        vm_page_t m;
        int error;

        /* Do some sanity checks first. */
        if ((offset & (AGP_PAGE_SIZE - 1)) != 0 ||
            offset + mem->am_size > AGP_GET_APERTURE(dev)) {
                device_printf(dev, "binding memory at bad offset %#x\n",
                    (int)offset);
                return EINVAL;
        }

        /*
         * Allocate the pages early, before acquiring the lock,
         * because vm_page_grab() may sleep and we can't hold a mutex
         * while sleeping.
         */
        VM_OBJECT_WLOCK(mem->am_obj);
        for (i = 0; i < mem->am_size; i += PAGE_SIZE) {
                /*
                 * Find a page from the object and wire it
                 * down. This page will be mapped using one or more
                 * entries in the GATT (assuming that PAGE_SIZE >=
                 * AGP_PAGE_SIZE. If this is the first call to bind,
                 * the pages will be allocated and zeroed.
                 */
                m = vm_page_grab(mem->am_obj, OFF_TO_IDX(i),
                    VM_ALLOC_WIRED | VM_ALLOC_ZERO);
                AGP_DPF("found page pa=%#jx\n", (uintmax_t)VM_PAGE_TO_PHYS(m));
        }
        VM_OBJECT_WUNLOCK(mem->am_obj);
        vm_page_iter_init(&pages, mem->am_obj);
        mtx_lock(&sc->as_lock);

        if (mem->am_is_bound) {
                device_printf(dev, "memory already bound\n");
                error = EINVAL;
                VM_OBJECT_WLOCK(mem->am_obj);
                i = 0;
                goto bad;
        }

        /*
         * Bind the individual pages and flush the chipset's
         * TLB.
         */
        VM_OBJECT_WLOCK(mem->am_obj);
        for (i = 0; i < mem->am_size; i += PAGE_SIZE) {
                m = vm_radix_iter_lookup(&pages, OFF_TO_IDX(i));

                /*
                 * Install entries in the GATT, making sure that if
                 * AGP_PAGE_SIZE < PAGE_SIZE and mem->am_size is not
                 * aligned to PAGE_SIZE, we don't modify too many GATT 
                 * entries.
                 */
                for (j = 0; j < PAGE_SIZE && i + j < mem->am_size;
                     j += AGP_PAGE_SIZE) {
                        vm_offset_t pa = VM_PAGE_TO_PHYS(m) + j;
                        AGP_DPF("binding offset %#jx to pa %#jx\n",
                                (uintmax_t)offset + i + j, (uintmax_t)pa);
                        error = AGP_BIND_PAGE(dev, offset + i + j, pa);
                        if (error) {
                                /*
                                 * Bail out. Reverse all the mappings
                                 * and unwire the pages.
                                 */
                                for (k = 0; k < i + j; k += AGP_PAGE_SIZE)
                                        AGP_UNBIND_PAGE(dev, offset + k);
                                goto bad;
                        }
                }
                vm_page_xunbusy(m);
        }
        VM_OBJECT_WUNLOCK(mem->am_obj);

        /*
         * Make sure the chipset gets the new mappings.
         */
        AGP_FLUSH_TLB(dev);

        mem->am_offset = offset;
        mem->am_is_bound = 1;

        mtx_unlock(&sc->as_lock);

        return 0;
bad:
        mtx_unlock(&sc->as_lock);
        VM_OBJECT_ASSERT_WLOCKED(mem->am_obj);
        for (k = 0; k < mem->am_size; k += PAGE_SIZE) {
                m = vm_radix_iter_lookup(&pages, OFF_TO_IDX(k));
                if (k >= i)
                        vm_page_xunbusy(m);
                vm_page_unwire(m, PQ_INACTIVE);
        }
        VM_OBJECT_WUNLOCK(mem->am_obj);

        return error;
}

int
agp_generic_unbind_memory(device_t dev, struct agp_memory *mem)
{
        struct pctrie_iter pages;
        struct agp_softc *sc = device_get_softc(dev);
        vm_page_t m;
        int i;

        mtx_lock(&sc->as_lock);

        if (!mem->am_is_bound) {
                device_printf(dev, "memory is not bound\n");
                mtx_unlock(&sc->as_lock);
                return EINVAL;
        }

        /*
         * Unbind the individual pages and flush the chipset's
         * TLB. Unwire the pages so they can be swapped.
         */
        for (i = 0; i < mem->am_size; i += AGP_PAGE_SIZE)
                AGP_UNBIND_PAGE(dev, mem->am_offset + i);

        AGP_FLUSH_TLB(dev);

        vm_page_iter_init(&pages, mem->am_obj);
        VM_OBJECT_WLOCK(mem->am_obj);
        for (i = 0; i < mem->am_size; i += PAGE_SIZE) {
                m = vm_radix_iter_lookup(&pages, atop(i));
                vm_page_unwire(m, PQ_INACTIVE);
        }
        VM_OBJECT_WUNLOCK(mem->am_obj);

        mem->am_offset = 0;
        mem->am_is_bound = 0;

        mtx_unlock(&sc->as_lock);

        return 0;
}

/* Helper functions for implementing user/kernel api */

static int
agp_acquire_helper(device_t dev, enum agp_acquire_state state)
{
        struct agp_softc *sc = device_get_softc(dev);

        if (sc->as_state != AGP_ACQUIRE_FREE)
                return EBUSY;
        sc->as_state = state;

        return 0;
}

static int
agp_release_helper(device_t dev, enum agp_acquire_state state)
{
        struct agp_softc *sc = device_get_softc(dev);

        if (sc->as_state == AGP_ACQUIRE_FREE)
                return 0;

        if (sc->as_state != state)
                return EBUSY;

        sc->as_state = AGP_ACQUIRE_FREE;
        return 0;
}

static struct agp_memory *
agp_find_memory(device_t dev, int id)
{
        struct agp_softc *sc = device_get_softc(dev);
        struct agp_memory *mem;

        AGP_DPF("searching for memory block %d\n", id);
        TAILQ_FOREACH(mem, &sc->as_memory, am_link) {
                AGP_DPF("considering memory block %d\n", mem->am_id);
                if (mem->am_id == id)
                        return mem;
        }
        return 0;
}

/* Implementation of the userland ioctl api */

static int
agp_info_user(device_t dev, agp_info *info)
{
        struct agp_softc *sc = device_get_softc(dev);

        bzero(info, sizeof *info);
        info->bridge_id = pci_get_devid(dev);
        info->agp_mode = 
            pci_read_config(dev, agp_find_caps(dev) + AGP_STATUS, 4);
        if (sc->as_aperture)
                info->aper_base = rman_get_start(sc->as_aperture);
        else
                info->aper_base = 0;
        info->aper_size = AGP_GET_APERTURE(dev) >> 20;
        info->pg_total = info->pg_system = sc->as_maxmem >> AGP_PAGE_SHIFT;
        info->pg_used = sc->as_allocated >> AGP_PAGE_SHIFT;

        return 0;
}

static int
agp_setup_user(device_t dev, agp_setup *setup)
{
        return AGP_ENABLE(dev, setup->agp_mode);
}

static int
agp_allocate_user(device_t dev, agp_allocate *alloc)
{
        struct agp_memory *mem;

        mem = AGP_ALLOC_MEMORY(dev,
                               alloc->type,
                               alloc->pg_count << AGP_PAGE_SHIFT);
        if (mem) {
                alloc->key = mem->am_id;
                alloc->physical = mem->am_physical;
                return 0;
        } else {
                return ENOMEM;
        }
}

static int
agp_deallocate_user(device_t dev, int id)
{
        struct agp_memory *mem = agp_find_memory(dev, id);

        if (mem) {
                AGP_FREE_MEMORY(dev, mem);
                return 0;
        } else {
                return ENOENT;
        }
}

static int
agp_bind_user(device_t dev, agp_bind *bind)
{
        struct agp_memory *mem = agp_find_memory(dev, bind->key);

        if (!mem)
                return ENOENT;

        return AGP_BIND_MEMORY(dev, mem, bind->pg_start << AGP_PAGE_SHIFT);
}

static int
agp_unbind_user(device_t dev, agp_unbind *unbind)
{
        struct agp_memory *mem = agp_find_memory(dev, unbind->key);

        if (!mem)
                return ENOENT;

        return AGP_UNBIND_MEMORY(dev, mem);
}

static int
agp_chipset_flush(device_t dev)
{

        return (AGP_CHIPSET_FLUSH(dev));
}

static int
agp_open(struct cdev *kdev, int oflags, int devtype, struct thread *td)
{
        device_t dev = kdev->si_drv1;
        struct agp_softc *sc = device_get_softc(dev);

        if (!sc->as_isopen) {
                sc->as_isopen = 1;
                device_busy(dev);
        }

        return 0;
}

static int
agp_close(struct cdev *kdev, int fflag, int devtype, struct thread *td)
{
        device_t dev = kdev->si_drv1;
        struct agp_softc *sc = device_get_softc(dev);
        struct agp_memory *mem;

        /*
         * Clear the GATT and force release on last close
         */
        while ((mem = TAILQ_FIRST(&sc->as_memory)) != NULL) {
                if (mem->am_is_bound)
                        AGP_UNBIND_MEMORY(dev, mem);
                AGP_FREE_MEMORY(dev, mem);
        }
        if (sc->as_state == AGP_ACQUIRE_USER)
                agp_release_helper(dev, AGP_ACQUIRE_USER);
        sc->as_isopen = 0;
        device_unbusy(dev);

        return 0;
}

static int
agp_ioctl(struct cdev *kdev, u_long cmd, caddr_t data, int fflag, struct thread *td)
{
        device_t dev = kdev->si_drv1;

        switch (cmd) {
        case AGPIOC_INFO:
                return agp_info_user(dev, (agp_info *) data);

        case AGPIOC_ACQUIRE:
                return agp_acquire_helper(dev, AGP_ACQUIRE_USER);

        case AGPIOC_RELEASE:
                return agp_release_helper(dev, AGP_ACQUIRE_USER);

        case AGPIOC_SETUP:
                return agp_setup_user(dev, (agp_setup *)data);

        case AGPIOC_ALLOCATE:
                return agp_allocate_user(dev, (agp_allocate *)data);

        case AGPIOC_DEALLOCATE:
                return agp_deallocate_user(dev, *(int *) data);

        case AGPIOC_BIND:
                return agp_bind_user(dev, (agp_bind *)data);

        case AGPIOC_UNBIND:
                return agp_unbind_user(dev, (agp_unbind *)data);

        case AGPIOC_CHIPSET_FLUSH:
                return agp_chipset_flush(dev);
        }

        return EINVAL;
}

static int
agp_mmap(struct cdev *kdev, vm_ooffset_t offset, vm_paddr_t *paddr,
    int prot, vm_memattr_t *memattr)
{
        device_t dev = kdev->si_drv1;
        struct agp_softc *sc = device_get_softc(dev);

        if (offset > AGP_GET_APERTURE(dev))
                return -1;
        if (sc->as_aperture == NULL)
                return -1;
        *paddr = rman_get_start(sc->as_aperture) + offset;
        return 0;
}

/* Implementation of the kernel api */

device_t
agp_find_device(void)
{
        device_t *children, child;
        int i, count;

        if (!agp_devclass)
                return NULL;
        if (devclass_get_devices(agp_devclass, &children, &count) != 0)
                return NULL;
        child = NULL;
        for (i = 0; i < count; i++) {
                if (device_is_attached(children[i])) {
                        child = children[i];
                        break;
                }
        }
        free(children, M_TEMP);
        return child;
}

enum agp_acquire_state
agp_state(device_t dev)
{
        struct agp_softc *sc = device_get_softc(dev);
        return sc->as_state;
}

void
agp_get_info(device_t dev, struct agp_info *info)
{
        struct agp_softc *sc = device_get_softc(dev);

        info->ai_mode =
                pci_read_config(dev, agp_find_caps(dev) + AGP_STATUS, 4);
        if (sc->as_aperture != NULL)
                info->ai_aperture_base = rman_get_start(sc->as_aperture);
        else
                info->ai_aperture_base = 0;
        info->ai_aperture_size = AGP_GET_APERTURE(dev);
        info->ai_memory_allowed = sc->as_maxmem;
        info->ai_memory_used = sc->as_allocated;
}

int
agp_acquire(device_t dev)
{
        return agp_acquire_helper(dev, AGP_ACQUIRE_KERNEL);
}

int
agp_release(device_t dev)
{
        return agp_release_helper(dev, AGP_ACQUIRE_KERNEL);
}

int
agp_enable(device_t dev, u_int32_t mode)
{
        return AGP_ENABLE(dev, mode);
}

void *agp_alloc_memory(device_t dev, int type, vm_size_t bytes)
{
        return  (void *) AGP_ALLOC_MEMORY(dev, type, bytes);
}

void agp_free_memory(device_t dev, void *handle)
{
        struct agp_memory *mem = (struct agp_memory *) handle;
        AGP_FREE_MEMORY(dev, mem);
}

int agp_bind_memory(device_t dev, void *handle, vm_offset_t offset)
{
        struct agp_memory *mem = (struct agp_memory *) handle;
        return AGP_BIND_MEMORY(dev, mem, offset);
}

int agp_unbind_memory(device_t dev, void *handle)
{
        struct agp_memory *mem = (struct agp_memory *) handle;
        return AGP_UNBIND_MEMORY(dev, mem);
}

void agp_memory_info(device_t dev, void *handle, struct
                     agp_memory_info *mi)
{
        struct agp_memory *mem = (struct agp_memory *) handle;

        mi->ami_size = mem->am_size;
        mi->ami_physical = mem->am_physical;
        mi->ami_offset = mem->am_offset;
        mi->ami_is_bound = mem->am_is_bound;
}

int
agp_bind_pages(device_t dev, vm_page_t *pages, vm_size_t size,
    vm_offset_t offset)
{
        struct agp_softc *sc;
        vm_offset_t i, j, k, pa;
        vm_page_t m;
        int error;

        if ((size & (AGP_PAGE_SIZE - 1)) != 0 ||
            (offset & (AGP_PAGE_SIZE - 1)) != 0)
                return (EINVAL);

        sc = device_get_softc(dev);

        mtx_lock(&sc->as_lock);
        for (i = 0; i < size; i += PAGE_SIZE) {
                m = pages[OFF_TO_IDX(i)];
                KASSERT(vm_page_wired(m),
                    ("agp_bind_pages: page %p hasn't been wired", m));

                /*
                 * Install entries in the GATT, making sure that if
                 * AGP_PAGE_SIZE < PAGE_SIZE and size is not
                 * aligned to PAGE_SIZE, we don't modify too many GATT 
                 * entries.
                 */
                for (j = 0; j < PAGE_SIZE && i + j < size; j += AGP_PAGE_SIZE) {
                        pa = VM_PAGE_TO_PHYS(m) + j;
                        AGP_DPF("binding offset %#jx to pa %#jx\n",
                                (uintmax_t)offset + i + j, (uintmax_t)pa);
                        error = AGP_BIND_PAGE(dev, offset + i + j, pa);
                        if (error) {
                                /*
                                 * Bail out. Reverse all the mappings.
                                 */
                                for (k = 0; k < i + j; k += AGP_PAGE_SIZE)
                                        AGP_UNBIND_PAGE(dev, offset + k);

                                mtx_unlock(&sc->as_lock);
                                return (error);
                        }
                }
        }

        AGP_FLUSH_TLB(dev);

        mtx_unlock(&sc->as_lock);
        return (0);
}

int
agp_unbind_pages(device_t dev, vm_size_t size, vm_offset_t offset)
{
        struct agp_softc *sc;
        vm_offset_t i;

        if ((size & (AGP_PAGE_SIZE - 1)) != 0 ||
            (offset & (AGP_PAGE_SIZE - 1)) != 0)
                return (EINVAL);

        sc = device_get_softc(dev);

        mtx_lock(&sc->as_lock);
        for (i = 0; i < size; i += AGP_PAGE_SIZE)
                AGP_UNBIND_PAGE(dev, offset + i);

        AGP_FLUSH_TLB(dev);

        mtx_unlock(&sc->as_lock);
        return (0);
}