xref: /openbsd/sys/dev/pci/agp.c (revision 8f8e4ea1)

/* $OpenBSD: agp.c,v 1.20 2008/04/09 18:59:58 oga Exp $ */
/*-
 * 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.
 *
 *	$FreeBSD: src/sys/pci/agp.c,v 1.12 2001/05/19 01:28:07 alfred Exp $
 */

#include <sys/param.h>
#include <sys/malloc.h>
#include <sys/agpio.h>
#include <sys/fcntl.h>
#include <sys/ioctl.h>

#include <uvm/uvm.h>

#include <dev/pci/pcivar.h>
#include <dev/pci/pcidevs.h>

#include <dev/ic/mc6845reg.h>
#include <dev/ic/pcdisplayvar.h>
#include <dev/ic/vgareg.h>
#include <dev/ic/vgavar.h>

#include <dev/pci/agpvar.h>
#include <dev/pci/agpreg.h>

#include "agp_ali.h"
#include "agp_amd.h"
#include "agp_amd64.h"
#include "agp_apple.h"
#include "agp_i810.h"
#include "agp_intel.h"
#include "agp_sis.h"
#include "agp_via.h"

struct agp_memory *agp_find_memory(struct agp_softc *sc, int id);
const struct agp_product *agp_lookup(struct pci_attach_args *pa);
/* userland ioctl functions */
int	agp_info_user(void *, agp_info *);
int	agp_setup_user(void *, agp_setup *);
int	agp_allocate_user(void *, agp_allocate *);
int	agp_deallocate_user(void *, int);
int	agp_bind_user(void *, agp_bind *);
int	agp_unbind_user(void *, agp_unbind *);
int	agp_acquire_helper(void *dev, enum agp_acquire_state state);
int	agp_release_helper(void *dev, enum agp_acquire_state state);

const struct agp_product agp_products[] = {
#if NAGP_ALI > 0
	{ PCI_VENDOR_ALI, -1, agp_ali_attach },
#endif
#if NAGP_AMD > 0
	{ PCI_VENDOR_AMD, -1, agp_amd_attach },
#endif
#if NAGP_I810 > 0
	{ PCI_VENDOR_INTEL, PCI_PRODUCT_INTEL_82810_HB, agp_i810_attach },
	{ PCI_VENDOR_INTEL, PCI_PRODUCT_INTEL_82810_DC100_HB, agp_i810_attach },
	{ PCI_VENDOR_INTEL, PCI_PRODUCT_INTEL_82810E_HB, agp_i810_attach },
	{ PCI_VENDOR_INTEL, PCI_PRODUCT_INTEL_82815_HB, agp_i810_attach },
	{ PCI_VENDOR_INTEL, PCI_PRODUCT_INTEL_82830M_HB, agp_i810_attach },
	{ PCI_VENDOR_INTEL, PCI_PRODUCT_INTEL_82845G_HB, agp_i810_attach },
	{ PCI_VENDOR_INTEL, PCI_PRODUCT_INTEL_82855GM_HB, agp_i810_attach },
	{ PCI_VENDOR_INTEL, PCI_PRODUCT_INTEL_82865G_HB, agp_i810_attach },
	{ PCI_VENDOR_INTEL, PCI_PRODUCT_INTEL_82915G_HB, agp_i810_attach },
	{ PCI_VENDOR_INTEL, PCI_PRODUCT_INTEL_82915GM_HB, agp_i810_attach },
	{ PCI_VENDOR_INTEL, PCI_PRODUCT_INTEL_82945G_HB, agp_i810_attach },
	{ PCI_VENDOR_INTEL, PCI_PRODUCT_INTEL_82945GM_HB, agp_i810_attach },
	{ PCI_VENDOR_INTEL, PCI_PRODUCT_INTEL_82G965_HB, agp_i810_attach },
	{ PCI_VENDOR_INTEL, PCI_PRODUCT_INTEL_82Q965_HB, agp_i810_attach },
	{ PCI_VENDOR_INTEL, PCI_PRODUCT_INTEL_82GM965_HB, agp_i810_attach },
	{ PCI_VENDOR_INTEL, PCI_PRODUCT_INTEL_82G33_HB, agp_i810_attach },
#endif
#if NAGP_INTEL > 0
	{ PCI_VENDOR_INTEL, -1, agp_intel_attach },
#endif
#if NAGP_SIS > 0
	{ PCI_VENDOR_SIS, -1, agp_sis_attach },
#endif
#if NAGP_VIA > 0
	{ PCI_VENDOR_VIATECH, -1, agp_via_attach },
#endif
	{ 0, 0, NULL }
};


int
agp_probe(struct device *parent, void *match, void *aux)
{
	struct agpbus_attach_args *aaa = aux;
	struct pci_attach_args *pa = &aaa->apa_pci_args;

	/* pci_args must be a pchb */
	if (PCI_CLASS(pa->pa_class) != PCI_CLASS_BRIDGE ||
	    PCI_SUBCLASS(pa->pa_class) != PCI_SUBCLASS_BRIDGE_HOST)
		return (0);

	if (agp_lookup(pa) == NULL)
		return (0);

	return (1);
}

void
agp_attach(struct device *parent, struct device *self, void *aux)
{
	struct agpbus_attach_args *aaa = aux;
	struct pci_attach_args *pa = &aaa->apa_pci_args;
	struct agp_softc *sc = (struct agp_softc *)self;
	const struct agp_product *ap;
	u_int memsize;
	int i, ret;

	ap = agp_lookup(pa);
	if (ap) {
		static const 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	 (sizeof(agp_max)/sizeof(agp_max[0]))

		/*
		 * Work out an upper bound for agp memory allocation. This
		 * uses a heuristic table from the Linux driver.
		 */
		memsize = ptoa(physmem) >> 20;

		for (i = 0; i < agp_max_size && memsize > agp_max[i][0]; i++)
			;
		if (i == agp_max_size)
			i = agp_max_size - 1;
		sc->sc_maxmem = agp_max[i][1] << 20;

		/*
		 * The lock is used to prevent re-entry to
		 * agp_generic_bind_memory() since that function can sleep.
		 */

		rw_init(&sc->sc_lock, "agplk");

		TAILQ_INIT(&sc->sc_memory);

		sc->sc_pcitag = pa->pa_tag;
		sc->sc_pc = pa->pa_pc;
		sc->sc_id = pa->pa_id;
		sc->sc_dmat = pa->pa_dmat;

		pci_get_capability(sc->sc_pc, sc->sc_pcitag, PCI_CAP_AGP,
		    &sc->sc_capoff, NULL);

		printf(": ");
		ret = (*ap->ap_attach)(sc, pa);
		if (ret == 0)
			printf("aperture at 0x%lx, size 0x%lx\n",
			    (u_long)sc->sc_apaddr,
			    (u_long)AGP_GET_APERTURE(sc));
		else {
			sc->sc_chipc = NULL;
		}
	}
}

struct cfattach agp_ca = {
        sizeof (struct agp_softc), agp_probe, agp_attach,
	NULL, NULL
};

struct cfdriver agp_cd = {
	NULL, "agp", DV_DULL
};

paddr_t
agpmmap(void *v, off_t off, int prot)
{
	struct agp_softc* sc = (struct agp_softc *)v;

	if (sc->sc_apaddr) {

		if (off > AGP_GET_APERTURE(sc))
			return (-1);

		/*
		 * XXX this should use bus_space_mmap() but it's not
		 * availiable on all archs.
		 */
		return atop(sc->sc_apaddr + off);
	}
	return (-1);
}

int
agpopen(dev_t dev, int oflags, int devtype, struct proc *p)
{
        struct agp_softc *sc = agp_find_device(AGPUNIT(dev));

        if (sc == NULL)
                return (ENXIO);

        if (sc->sc_chipc == NULL)
                return (ENXIO);

        if (!sc->sc_opened)
                sc->sc_opened = 1;
        else
                return (EBUSY);

        return (0);
}


int
agpioctl(dev_t dev, u_long cmd, caddr_t addr, int flag, struct proc *pb)
{
	struct agp_softc *sc = agp_find_device(AGPUNIT(dev));

	if (sc ==NULL)
		return (ENODEV);

	if (sc->sc_methods == NULL || sc->sc_chipc == NULL)
		return (ENXIO);

	if (cmd != AGPIOC_INFO && !(flag & FWRITE))
		return (EPERM);

	switch(cmd) {
	case AGPIOC_INFO:
		return (agp_info_user(sc, (agp_info *)addr));

	case AGPIOC_ACQUIRE:
		return (agp_acquire_helper(sc, AGP_ACQUIRE_USER));

	case AGPIOC_RELEASE:
		return (agp_release_helper(sc, AGP_ACQUIRE_USER));

	case AGPIOC_SETUP:
		return (agp_setup_user(sc, (agp_setup *)addr));

	case AGPIOC_ALLOCATE:
		return (agp_allocate_user(sc, (agp_allocate *)addr));

	case AGPIOC_DEALLOCATE:
		return (agp_deallocate_user(sc, *(int *)addr));

	case AGPIOC_BIND:
		return (agp_bind_user(sc, (agp_bind *)addr));

	case AGPIOC_UNBIND:
		return (agp_unbind_user(sc, (agp_unbind *)addr));

	default:
		return (ENOTTY);
	}

}

int
agpclose(dev_t dev, int flags, int devtype, struct proc *p)
{
	struct agp_softc *sc = agp_find_device(AGPUNIT(dev));
	struct agp_memory *mem;

	/*
         * Clear the GATT and force release on last close
         */
	if (sc->sc_state == AGP_ACQUIRE_USER) {
		while ((mem = TAILQ_FIRST(&sc->sc_memory)) != 0) {
			if (mem->am_is_bound)
				AGP_UNBIND_MEMORY(sc, mem);
			AGP_FREE_MEMORY(sc, mem);
		}
                agp_release_helper(sc, AGP_ACQUIRE_USER);
	}
        sc->sc_opened = 0;

	return (0);
}

struct agp_memory *
agp_find_memory(struct agp_softc *sc, int id)
{
	struct agp_memory *mem;

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

const struct agp_product *
agp_lookup(struct pci_attach_args *pa)
{
	const struct agp_product *ap;

	/* First find the vendor. */
	for (ap = agp_products; ap->ap_attach != NULL; ap++)
		if (ap->ap_vendor == PCI_VENDOR(pa->pa_id))
			break;

	if (ap->ap_attach == NULL)
		return (NULL);

	/* Now find the product within the vendor's domain. */
	for (; ap->ap_attach != NULL; ap++) {
		/* Ran out of this vendor's section of the table. */
		if (ap->ap_vendor != PCI_VENDOR(pa->pa_id))
			return (NULL);

		if (ap->ap_product == PCI_PRODUCT(pa->pa_id))
			break;		/* Exact match. */
		if (ap->ap_product == (u_int32_t) -1)
			break;		/* Wildcard match. */
	}

	if (ap->ap_attach == NULL)
		ap = NULL;

	return (ap);
}

int
agp_map_aperture(struct pci_attach_args *pa, struct agp_softc *sc, u_int32_t bar, u_int32_t memtype)
{
	/* Find the aperture. Don't map it (yet), this would eat KVA */
	if (pci_mapreg_info(pa->pa_pc, pa->pa_tag, bar,
	    memtype, &sc->sc_apaddr, &sc->sc_apsize,
	    &sc->sc_apflags) != 0)
		return (ENXIO);

	return (0);
}

u_int32_t
agp_generic_get_aperture(struct agp_softc *sc)
{
	return (sc->sc_apsize);
}

int
agp_generic_set_aperture(struct agp_softc *sc, u_int32_t aperture)
{
	if (aperture != AGP_GET_APERTURE(sc))
		return (EINVAL);

	return (0);
}

struct agp_gatt *
agp_alloc_gatt(struct agp_softc *sc)
{
	u_int32_t apsize = AGP_GET_APERTURE(sc);
	u_int32_t entries = apsize >> AGP_PAGE_SHIFT;
	struct agp_gatt *gatt;
	int nseg;

	gatt = malloc(sizeof(*gatt), M_AGP, M_NOWAIT | M_ZERO);
	if (!gatt)
		return (NULL);
	gatt->ag_entries = entries;

	if (agp_alloc_dmamem(sc->sc_dmat, entries * sizeof(u_int32_t),
	    0, &gatt->ag_dmamap, (caddr_t *)&gatt->ag_virtual,
	    &gatt->ag_physical, &gatt->ag_dmaseg, 1, &nseg) != 0)
		return (NULL);

	gatt->ag_size = entries * sizeof(u_int32_t);
	memset(gatt->ag_virtual, 0, gatt->ag_size);
	agp_flush_cache();

	return (gatt);
}

void
agp_free_gatt(struct agp_softc *sc, struct agp_gatt *gatt)
{
	agp_free_dmamem(sc->sc_dmat, gatt->ag_size, gatt->ag_dmamap,
	    (caddr_t)gatt->ag_virtual, &gatt->ag_dmaseg, 1);
	free(gatt, M_AGP);
}

int
agp_generic_detach(struct agp_softc *sc)
{
	agp_flush_cache();
	return (0);
}

int
agp_generic_enable(struct agp_softc *sc, u_int32_t mode)
{
	pcireg_t tstatus, mstatus;
	pcireg_t command;
	int rq, sba, fw, rate, capoff;

	if (pci_get_capability(sc->sc_pc, sc->sc_pcitag, PCI_CAP_AGP,
	    &capoff, NULL) == 0) {
		printf("agp_generic_enable: not an AGP capable device\n");
		return (-1);
	}

	tstatus = pci_conf_read(sc->sc_pc, sc->sc_pcitag,
	    sc->sc_capoff + AGP_STATUS);
	mstatus = pci_conf_read(sc->sc_pc, sc->sc_pcitag,
	    capoff + AGP_STATUS);

	/* 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_RATE_4x)
		rate = AGP_MODE_RATE_4x;
	else if (rate & AGP_MODE_RATE_2x)
		rate = AGP_MODE_RATE_2x;
	else
		rate = AGP_MODE_RATE_1x;

	/* Construct the new mode word and tell the hardware  */
	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_conf_write(sc->sc_pc, sc->sc_pcitag,
	    sc->sc_capoff + AGP_COMMAND, command);
	pci_conf_write(sc->sc_pc, sc->sc_pcitag, capoff + AGP_COMMAND, command);
	return (0);
}

struct agp_memory *
agp_generic_alloc_memory(struct agp_softc *sc, int type, vsize_t size)
{
	struct agp_memory *mem;

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

	mem = malloc(sizeof *mem, M_AGP, M_WAITOK | M_ZERO);

	if (bus_dmamap_create(sc->sc_dmat, size, size / PAGE_SIZE + 1,
	    size, 0, BUS_DMA_NOWAIT, &mem->am_dmamap) != 0) {
		free(mem, M_AGP);
		return (NULL);
	}

	mem->am_id = sc->sc_nextid++;
	mem->am_size = size;
	TAILQ_INSERT_TAIL(&sc->sc_memory, mem, am_link);
	sc->sc_allocated += size;

	return (mem);
}

int
agp_generic_free_memory(struct agp_softc *sc, struct agp_memory *mem)
{
	if (mem->am_is_bound)
		return (EBUSY);

	sc->sc_allocated -= mem->am_size;
	TAILQ_REMOVE(&sc->sc_memory, mem, am_link);
	bus_dmamap_destroy(sc->sc_dmat, mem->am_dmamap);
	free(mem, M_AGP);
	return (0);
}

int
agp_generic_bind_memory(struct agp_softc *sc, struct agp_memory *mem,
			off_t offset)
{
	bus_dma_segment_t *segs, *seg;
	bus_size_t done, j;
	bus_addr_t pa;
	off_t i, k;
	int nseg, error;

	rw_enter_write(&sc->sc_lock);

	if (mem->am_is_bound) {
		printf("AGP: memory already bound\n");
		rw_exit_write(&sc->sc_lock);
		return (EINVAL);
	}

	if (offset < 0
	    || (offset & (AGP_PAGE_SIZE - 1)) != 0
	    || offset + mem->am_size > AGP_GET_APERTURE(sc)) {
		printf("AGP: binding memory at bad offset %#lx\n",
		    (unsigned long) offset);
		rw_exit_write(&sc->sc_lock);
		return (EINVAL);
	}

	/*
	 * The memory here needs to be directly accessable from the
	 * AGP video card, so it should be allocated using bus_dma.
	 * However, it need not be contiguous, since individual pages
	 * are translated using the GATT.
	 */

	nseg = (mem->am_size + PAGE_SIZE - 1) / PAGE_SIZE;
	segs = malloc(nseg * sizeof *segs, M_AGP, M_WAITOK);
	if ((error = bus_dmamem_alloc(sc->sc_dmat, mem->am_size, PAGE_SIZE, 0,
	    segs, nseg, &mem->am_nseg, BUS_DMA_WAITOK)) != 0) {
		free(segs, M_AGP);
		rw_exit_write(&sc->sc_lock);
		AGP_DPF("bus_dmamem_alloc failed %d\n", error);
		return (error);
	}
	if ((error = bus_dmamem_map(sc->sc_dmat, segs, mem->am_nseg,
	    mem->am_size, &mem->am_virtual, BUS_DMA_WAITOK)) != 0) {
		bus_dmamem_free(sc->sc_dmat, segs, mem->am_nseg);
		free(segs, M_AGP);
		rw_exit_write(&sc->sc_lock);
		AGP_DPF("bus_dmamem_map failed %d\n", error);
		return (error);
	}
	if ((error = bus_dmamap_load(sc->sc_dmat, mem->am_dmamap,
	    mem->am_virtual, mem->am_size, NULL,
	    BUS_DMA_WAITOK)) != 0) {
		bus_dmamem_unmap(sc->sc_dmat, mem->am_virtual,
		    mem->am_size);
		bus_dmamem_free(sc->sc_dmat, segs, mem->am_nseg);
		free(segs, M_AGP);
		rw_exit_write(&sc->sc_lock);
		AGP_DPF("bus_dmamap_load failed %d\n", error);
		return (error);
	}
	mem->am_dmaseg = segs;

	/*
	 * Bind the individual pages and flush the chipset's
	 * TLB.
	 */
	done = 0;
	for (i = 0; i < mem->am_dmamap->dm_nsegs; i++) {
		seg = &mem->am_dmamap->dm_segs[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 < seg->ds_len && (done + j) < mem->am_size;
		    j += AGP_PAGE_SIZE) {
			pa = seg->ds_addr + j;
			AGP_DPF("binding offset %#lx to pa %#lx\n",
			    (unsigned long)(offset + done + j),
			    (unsigned long)pa);
			error = AGP_BIND_PAGE(sc, offset + done + j, pa);
			if (error) {
				/*
				 * Bail out. Reverse all the mappings
				 * and unwire the pages.
				 */
				for (k = 0; k < done + j; k += AGP_PAGE_SIZE)
					AGP_UNBIND_PAGE(sc, offset + k);

				bus_dmamap_unload(sc->sc_dmat, mem->am_dmamap);
				bus_dmamem_unmap(sc->sc_dmat, mem->am_virtual,
				    mem->am_size);
				bus_dmamem_free(sc->sc_dmat, mem->am_dmaseg,
				    mem->am_nseg);
				free(mem->am_dmaseg, M_AGP);
				rw_exit_write(&sc->sc_lock);
				AGP_DPF("AGP_BIND_PAGE failed %d\n", error);
				return (error);
			}
		}
		done += seg->ds_len;
	}

	/*
	 * Flush the cpu cache since we are providing a new mapping
	 * for these pages.
	 */
	agp_flush_cache();

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

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

	rw_exit_write(&sc->sc_lock);

	return (0);
}

int
agp_generic_unbind_memory(struct agp_softc *sc, struct agp_memory *mem)
{
	int i;

	rw_enter_write(&sc->sc_lock);

	if (!mem->am_is_bound) {
		printf("AGP: memory is not bound\n");
		rw_exit_write(&sc->sc_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(sc, mem->am_offset + i);

	agp_flush_cache();
	AGP_FLUSH_TLB(sc);

	bus_dmamap_unload(sc->sc_dmat, mem->am_dmamap);
	bus_dmamem_unmap(sc->sc_dmat, mem->am_virtual, mem->am_size);
	bus_dmamem_free(sc->sc_dmat, mem->am_dmaseg, mem->am_nseg);

	free(mem->am_dmaseg, M_AGP);

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

	rw_exit_write(&sc->sc_lock);

	return (0);
}

int
agp_alloc_dmamem(bus_dma_tag_t tag, size_t size, int flags,
    bus_dmamap_t *mapp, caddr_t *vaddr, bus_addr_t *baddr,
    bus_dma_segment_t *seg, int nseg, int *rseg)

{
	int error, level = 0;

	if ((error = bus_dmamem_alloc(tag, size, PAGE_SIZE, 0,
	    seg, nseg, rseg, BUS_DMA_NOWAIT)) != 0)
		goto out;
	level++;

	if ((error = bus_dmamem_map(tag, seg, *rseg, size, vaddr,
	    BUS_DMA_NOWAIT | flags)) != 0)
		goto out;
	level++;

	if ((error = bus_dmamap_create(tag, size, *rseg, size, 0,
	    BUS_DMA_NOWAIT, mapp)) != 0)
		goto out;
	level++;

	if ((error = bus_dmamap_load(tag, *mapp, *vaddr, size, NULL,
	    BUS_DMA_NOWAIT)) != 0)
		goto out;

	*baddr = (*mapp)->dm_segs[0].ds_addr;

	return (0);
out:
	switch (level) {
	case 3:
		bus_dmamap_destroy(tag, *mapp);
		/* FALLTHROUGH */
	case 2:
		bus_dmamem_unmap(tag, *vaddr, size);
		/* FALLTHROUGH */
	case 1:
		bus_dmamem_free(tag, seg, *rseg);
		break;
	default:
		break;
	}

	return (error);
}

void
agp_free_dmamem(bus_dma_tag_t tag, size_t size, bus_dmamap_t map,
    caddr_t vaddr, bus_dma_segment_t *seg, int nseg)
{

	bus_dmamap_unload(tag, map);
	bus_dmamap_destroy(tag, map);
	bus_dmamem_unmap(tag, vaddr, size);
	bus_dmamem_free(tag, seg, nseg);
}

/* Helper functions used in both user and kernel APIs */

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

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

	return (0);
}

int
agp_release_helper(void *dev, enum agp_acquire_state state)
{
	struct agp_softc *sc = (struct agp_softc *)dev;
	struct agp_memory* mem;

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

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

	/*
	 * Clear out the aperture and free any
	 * outstanding memory blocks.
	 */
	TAILQ_FOREACH(mem, &sc->sc_memory, am_link) {
		if (mem->am_is_bound) {
			printf("agp_release_helper: mem %d is bound\n",
			    mem->am_id);
			AGP_UNBIND_MEMORY(sc, mem);
		}
	}
	sc->sc_state = AGP_ACQUIRE_FREE;
	return (0);
}

/* Implementation of the userland ioctl API */

int
agp_info_user(void *dev, agp_info *info)
{
	struct agp_softc *sc = (struct agp_softc *) dev;

	if (!sc->sc_chipc)
		return (ENXIO);

	bzero(info, sizeof *info);
	info->bridge_id = sc->sc_id;
	if (sc->sc_capoff != 0)
		info->agp_mode = pci_conf_read(sc->sc_pc, sc->sc_pcitag,
		    AGP_STATUS + sc->sc_capoff);
	else
		info->agp_mode = 0; /* i810 doesn't have real AGP */
	info->aper_base = sc->sc_apaddr;
	info->aper_size = AGP_GET_APERTURE(sc) >> 20;
	info->pg_total =
	info->pg_system = sc->sc_maxmem >> AGP_PAGE_SHIFT;
	info->pg_used = sc->sc_allocated >> AGP_PAGE_SHIFT;

	return (0);
}

int
agp_setup_user(void *dev, agp_setup *setup)
{
	struct agp_softc *sc = (struct agp_softc *) dev;

	return (AGP_ENABLE(sc, setup->agp_mode));
}

int
agp_allocate_user(void *dev, agp_allocate *alloc)
{
	struct agp_softc *sc = (struct agp_softc *) dev;
	struct agp_memory* mem;
	size_t size = alloc->pg_count << AGP_PAGE_SHIFT;

	if (sc->sc_allocated + size > sc->sc_maxmem)
		return (EINVAL);

	mem = AGP_ALLOC_MEMORY(sc, alloc->type, size);
	if (mem) {
		alloc->key = mem->am_id;
		alloc->physical = mem->am_physical;
		return (0);
	} else
		return (ENOMEM);
}

int
agp_deallocate_user(void *dev, int id)
{
	struct agp_softc *sc = (struct agp_softc *) dev;
	struct agp_memory *mem = agp_find_memory(sc, id);
	if (mem) {
		AGP_FREE_MEMORY(sc, mem);
		return (0);
	} else
		return (ENOENT);
}

int
agp_bind_user(void *dev, agp_bind *bind)
{
	struct agp_softc *sc = (struct agp_softc *) dev;
	struct agp_memory *mem = agp_find_memory(sc, bind->key);

	if (!mem)
		return (ENOENT);

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


int
agp_unbind_user(void *dev, agp_unbind *unbind)
{
	struct agp_softc *sc = (struct agp_softc *) dev;
	struct agp_memory *mem = agp_find_memory(sc, unbind->key);

	if (!mem)
		return (ENOENT);

	return (AGP_UNBIND_MEMORY(sc, mem));
}

/* Implementation of the kernel api */

void *
agp_find_device(int unit)
{
	if (unit >= agp_cd.cd_ndevs || unit < 0)
		return (NULL);
	return (agp_cd.cd_devs[unit]);
}

enum agp_acquire_state
agp_state(void *dev)
{
	struct agp_softc *sc = (struct agp_softc *) dev;
        return (sc->sc_state);
}

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

        info->ai_mode = pci_conf_read(sc->sc_pc, sc->sc_pcitag,
	    sc->sc_capoff + AGP_STATUS);
	info->ai_aperture_base = sc->sc_apaddr;
	info->ai_aperture_size = sc->sc_apsize;
        info->ai_memory_allowed = sc->sc_maxmem;
        info->ai_memory_used = sc->sc_allocated;
}

int
agp_acquire(void *dev)
{
	struct agp_softc *sc = (struct agp_softc *)dev;

        return (agp_acquire_helper(sc, AGP_ACQUIRE_KERNEL));
}

int
agp_release(void *dev)
{
	struct agp_softc *sc = (struct agp_softc *)dev;

        return (agp_release_helper(sc, AGP_ACQUIRE_KERNEL));
}

int
agp_enable(void *dev, u_int32_t mode)
{
	struct agp_softc *sc = (struct agp_softc *) dev;

        return (AGP_ENABLE(sc, mode));
}

void *
agp_alloc_memory(void *dev, int type, vsize_t bytes)
{
	struct agp_softc *sc = (struct agp_softc *)dev;

        return  ((void *) AGP_ALLOC_MEMORY(sc, type, bytes));
}

void
agp_free_memory(void *dev, void *handle)
{
	struct agp_softc *sc = (struct agp_softc *) dev;
        struct agp_memory *mem = (struct agp_memory *) handle;

        AGP_FREE_MEMORY(sc, mem);
}

int
agp_bind_memory(void *dev, void *handle, off_t offset)
{
	struct agp_softc *sc = (struct agp_softc *) dev;
	struct agp_memory *mem = (struct agp_memory *) handle;

	return (AGP_BIND_MEMORY(sc, mem, offset));
}

int
agp_unbind_memory(void *dev, void *handle)
{
	struct agp_softc *sc = (struct agp_softc *) dev;
        struct agp_memory *mem = (struct agp_memory *) handle;

        return (AGP_UNBIND_MEMORY(sc, mem));
}

void
agp_memory_info(void *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;
}