path: root/freebsd/sys/dev/pci/pci_pci.c

#include <machine/rtems-bsd-kernel-space.h>

/*-
 * Copyright (c) 1994,1995 Stefan Esser, Wolfgang StanglMeier
 * Copyright (c) 2000 Michael Smith <msmith@freebsd.org>
 * Copyright (c) 2000 BSDi
 * 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.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * 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>
__FBSDID("$FreeBSD$");

/*
 * PCI:PCI bridge support.
 */

#include <rtems/bsd/sys/param.h>
#include <sys/bus.h>
#include <sys/kernel.h>
#include <sys/libkern.h>
#include <sys/malloc.h>
#include <sys/module.h>
#include <sys/rman.h>
#include <sys/sysctl.h>
#include <sys/systm.h>

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

#include <dev/pci/pcivar.h>
#include <dev/pci/pcireg.h>
#include <dev/pci/pcib_private.h>

#include <rtems/bsd/local/pcib_if.h>

static int		pcib_probe(device_t dev);

static device_method_t pcib_methods[] = {
    /* Device interface */
    DEVMETHOD(device_probe,		pcib_probe),
    DEVMETHOD(device_attach,		pcib_attach),
    DEVMETHOD(device_detach,		bus_generic_detach),
    DEVMETHOD(device_shutdown,		bus_generic_shutdown),
    DEVMETHOD(device_suspend,		bus_generic_suspend),
    DEVMETHOD(device_resume,		bus_generic_resume),

    /* Bus interface */
    DEVMETHOD(bus_read_ivar,		pcib_read_ivar),
    DEVMETHOD(bus_write_ivar,		pcib_write_ivar),
    DEVMETHOD(bus_alloc_resource,	pcib_alloc_resource),
#ifdef NEW_PCIB
    DEVMETHOD(bus_adjust_resource,	pcib_adjust_resource),
    DEVMETHOD(bus_release_resource,	pcib_release_resource),
#else
    DEVMETHOD(bus_adjust_resource,	bus_generic_adjust_resource),
    DEVMETHOD(bus_release_resource,	bus_generic_release_resource),
#endif
    DEVMETHOD(bus_activate_resource,	bus_generic_activate_resource),
    DEVMETHOD(bus_deactivate_resource,	bus_generic_deactivate_resource),
    DEVMETHOD(bus_setup_intr,		bus_generic_setup_intr),
    DEVMETHOD(bus_teardown_intr,	bus_generic_teardown_intr),

    /* pcib interface */
    DEVMETHOD(pcib_maxslots,		pcib_maxslots),
    DEVMETHOD(pcib_read_config,		pcib_read_config),
    DEVMETHOD(pcib_write_config,	pcib_write_config),
    DEVMETHOD(pcib_route_interrupt,	pcib_route_interrupt),
    DEVMETHOD(pcib_alloc_msi,		pcib_alloc_msi),
    DEVMETHOD(pcib_release_msi,		pcib_release_msi),
    DEVMETHOD(pcib_alloc_msix,		pcib_alloc_msix),
    DEVMETHOD(pcib_release_msix,	pcib_release_msix),
    DEVMETHOD(pcib_map_msi,		pcib_map_msi),

    DEVMETHOD_END
};

static devclass_t pcib_devclass;

DEFINE_CLASS_0(pcib, pcib_driver, pcib_methods, sizeof(struct pcib_softc));
DRIVER_MODULE(pcib, pci, pcib_driver, pcib_devclass, 0, 0);

#ifdef NEW_PCIB
/*
 * XXX Todo:
 * - properly handle the ISA enable bit.  If it is set, we should change
 *   the behavior of the I/O window resource and rman to not allocate the
 *   blocked ranges (upper 768 bytes of each 1K in the first 64k of the
 *   I/O port address space).
 */

/*
 * Is a resource from a child device sub-allocated from one of our
 * resource managers?
 */
static int
pcib_is_resource_managed(struct pcib_softc *sc, int type, struct resource *r)
{

	switch (type) {
	case SYS_RES_IOPORT:
		return (rman_is_region_manager(r, &sc->io.rman));
	case SYS_RES_MEMORY:
		/* Prefetchable resources may live in either memory rman. */
		if (rman_get_flags(r) & RF_PREFETCHABLE &&
		    rman_is_region_manager(r, &sc->pmem.rman))
			return (1);
		return (rman_is_region_manager(r, &sc->mem.rman));
	}
	return (0);
}

static int
pcib_is_window_open(struct pcib_window *pw)
{

	return (pw->valid && pw->base < pw->limit);
}

/*
 * XXX: If RF_ACTIVE did not also imply allocating a bus space tag and
 * handle for the resource, we could pass RF_ACTIVE up to the PCI bus
 * when allocating the resource windows and rely on the PCI bus driver
 * to do this for us.
 */
static void
pcib_activate_window(struct pcib_softc *sc, int type)
{

	PCI_ENABLE_IO(device_get_parent(sc->dev), sc->dev, type);
}

static void
pcib_write_windows(struct pcib_softc *sc, int mask)
{
	device_t dev;
	uint32_t val;

	dev = sc->dev;
	if (sc->io.valid && mask & WIN_IO) {
		val = pci_read_config(dev, PCIR_IOBASEL_1, 1);
		if ((val & PCIM_BRIO_MASK) == PCIM_BRIO_32) {
			pci_write_config(dev, PCIR_IOBASEH_1,
			    sc->io.base >> 16, 2);
			pci_write_config(dev, PCIR_IOLIMITH_1,
			    sc->io.limit >> 16, 2);
		}
		pci_write_config(dev, PCIR_IOBASEL_1, sc->io.base >> 8, 1);
		pci_write_config(dev, PCIR_IOLIMITL_1, sc->io.limit >> 8, 1);
	}

	if (mask & WIN_MEM) {
		pci_write_config(dev, PCIR_MEMBASE_1, sc->mem.base >> 16, 2);
		pci_write_config(dev, PCIR_MEMLIMIT_1, sc->mem.limit >> 16, 2);
	}

	if (sc->pmem.valid && mask & WIN_PMEM) {
		val = pci_read_config(dev, PCIR_PMBASEL_1, 2);
		if ((val & PCIM_BRPM_MASK) == PCIM_BRPM_64) {
			pci_write_config(dev, PCIR_PMBASEH_1,
			    sc->pmem.base >> 32, 4);
			pci_write_config(dev, PCIR_PMLIMITH_1,
			    sc->pmem.limit >> 32, 4);
		}
		pci_write_config(dev, PCIR_PMBASEL_1, sc->pmem.base >> 16, 2);
		pci_write_config(dev, PCIR_PMLIMITL_1, sc->pmem.limit >> 16, 2);
	}
}

static void
pcib_alloc_window(struct pcib_softc *sc, struct pcib_window *w, int type,
    int flags, pci_addr_t max_address)
{
	char buf[64];
	int error, rid;

	if (max_address != (u_long)max_address)
		max_address = ~0ul;
	w->rman.rm_start = 0;
	w->rman.rm_end = max_address;
	w->rman.rm_type = RMAN_ARRAY;
	snprintf(buf, sizeof(buf), "%s %s window",
	    device_get_nameunit(sc->dev), w->name);
	w->rman.rm_descr = strdup(buf, M_DEVBUF);
	error = rman_init(&w->rman);
	if (error)
		panic("Failed to initialize %s %s rman",
		    device_get_nameunit(sc->dev), w->name);

	if (!pcib_is_window_open(w))
		return;

	if (w->base > max_address || w->limit > max_address) {
		device_printf(sc->dev,
		    "initial %s window has too many bits, ignoring\n", w->name);
		return;
	}
	rid = w->reg;
	w->res = bus_alloc_resource(sc->dev, type, &rid, w->base, w->limit,
	    w->limit - w->base + 1, flags);
	if (w->res == NULL) {
		device_printf(sc->dev,
		    "failed to allocate initial %s window: %#jx-%#jx\n",
		    w->name, (uintmax_t)w->base, (uintmax_t)w->limit);
		w->base = max_address;
		w->limit = 0;
		pcib_write_windows(sc, w->mask);
		return;
	}
	pcib_activate_window(sc, type);

	error = rman_manage_region(&w->rman, rman_get_start(w->res),
	    rman_get_end(w->res));
	if (error)
		panic("Failed to initialize rman with resource");
}

/*
 * Initialize I/O windows.
 */
static void
pcib_probe_windows(struct pcib_softc *sc)
{
	pci_addr_t max;
	device_t dev;
	uint32_t val;

	dev = sc->dev;

	/* Determine if the I/O port window is implemented. */
	val = pci_read_config(dev, PCIR_IOBASEL_1, 1);
	if (val == 0) {
		/*
		 * If 'val' is zero, then only 16-bits of I/O space
		 * are supported.
		 */
		pci_write_config(dev, PCIR_IOBASEL_1, 0xff, 1);
		if (pci_read_config(dev, PCIR_IOBASEL_1, 1) != 0) {
			sc->io.valid = 1;
			pci_write_config(dev, PCIR_IOBASEL_1, 0, 1);
		}
	} else
		sc->io.valid = 1;

	/* Read the existing I/O port window. */
	if (sc->io.valid) {
		sc->io.reg = PCIR_IOBASEL_1;
		sc->io.step = 12;
		sc->io.mask = WIN_IO;
		sc->io.name = "I/O port";
		if ((val & PCIM_BRIO_MASK) == PCIM_BRIO_32) {
			sc->io.base = PCI_PPBIOBASE(
			    pci_read_config(dev, PCIR_IOBASEH_1, 2), val);
			sc->io.limit = PCI_PPBIOLIMIT(
			    pci_read_config(dev, PCIR_IOLIMITH_1, 2),
			    pci_read_config(dev, PCIR_IOLIMITL_1, 1));
			max = 0xffffffff;
		} else {
			sc->io.base = PCI_PPBIOBASE(0, val);
			sc->io.limit = PCI_PPBIOLIMIT(0,
			    pci_read_config(dev, PCIR_IOLIMITL_1, 1));
			max = 0xffff;
		}
		pcib_alloc_window(sc, &sc->io, SYS_RES_IOPORT, 0, max);
	}

	/* Read the existing memory window. */
	sc->mem.valid = 1;
	sc->mem.reg = PCIR_MEMBASE_1;
	sc->mem.step = 20;
	sc->mem.mask = WIN_MEM;
	sc->mem.name = "memory";
	sc->mem.base = PCI_PPBMEMBASE(0,
	    pci_read_config(dev, PCIR_MEMBASE_1, 2));
	sc->mem.limit = PCI_PPBMEMLIMIT(0,
	    pci_read_config(dev, PCIR_MEMLIMIT_1, 2));
	pcib_alloc_window(sc, &sc->mem, SYS_RES_MEMORY, 0, 0xffffffff);

	/* Determine if the prefetchable memory window is implemented. */
	val = pci_read_config(dev, PCIR_PMBASEL_1, 2);
	if (val == 0) {
		/*
		 * If 'val' is zero, then only 32-bits of memory space
		 * are supported.
		 */
		pci_write_config(dev, PCIR_PMBASEL_1, 0xffff, 2);
		if (pci_read_config(dev, PCIR_PMBASEL_1, 2) != 0) {
			sc->pmem.valid = 1;
			pci_write_config(dev, PCIR_PMBASEL_1, 0, 2);
		}
	} else
		sc->pmem.valid = 1;

	/* Read the existing prefetchable memory window. */
	if (sc->pmem.valid) {
		sc->pmem.reg = PCIR_PMBASEL_1;
		sc->pmem.step = 20;
		sc->pmem.mask = WIN_PMEM;
		sc->pmem.name = "prefetch";
		if ((val & PCIM_BRPM_MASK) == PCIM_BRPM_64) {
			sc->pmem.base = PCI_PPBMEMBASE(
			    pci_read_config(dev, PCIR_PMBASEH_1, 4), val);
			sc->pmem.limit = PCI_PPBMEMLIMIT(
			    pci_read_config(dev, PCIR_PMLIMITH_1, 4),
			    pci_read_config(dev, PCIR_PMLIMITL_1, 2));
			max = 0xffffffffffffffff;
		} else {
			sc->pmem.base = PCI_PPBMEMBASE(0, val);
			sc->pmem.limit = PCI_PPBMEMLIMIT(0,
			    pci_read_config(dev, PCIR_PMLIMITL_1, 2));
			max = 0xffffffff;
		}
		pcib_alloc_window(sc, &sc->pmem, SYS_RES_MEMORY,
		    RF_PREFETCHABLE, max);
	}
}

#else

/*
 * Is the prefetch window open (eg, can we allocate memory in it?)
 */
static int
pcib_is_prefetch_open(struct pcib_softc *sc)
{
	return (sc->pmembase > 0 && sc->pmembase < sc->pmemlimit);
}

/*
 * Is the nonprefetch window open (eg, can we allocate memory in it?)
 */
static int
pcib_is_nonprefetch_open(struct pcib_softc *sc)
{
	return (sc->membase > 0 && sc->membase < sc->memlimit);
}

/*
 * Is the io window open (eg, can we allocate ports in it?)
 */
static int
pcib_is_io_open(struct pcib_softc *sc)
{
	return (sc->iobase > 0 && sc->iobase < sc->iolimit);
}
#endif

/*
 * Generic device interface
 */
static int
pcib_probe(device_t dev)
{
    if ((pci_get_class(dev) == PCIC_BRIDGE) &&
	(pci_get_subclass(dev) == PCIS_BRIDGE_PCI)) {
	device_set_desc(dev, "PCI-PCI bridge");
	return(-10000);
    }
    return(ENXIO);
}

void
pcib_attach_common(device_t dev)
{
    struct pcib_softc	*sc;
#ifndef NEW_PCIB
    uint8_t		iolow;
#endif
    struct sysctl_ctx_list *sctx;
    struct sysctl_oid	*soid;

    sc = device_get_softc(dev);
    sc->dev = dev;

    /*
     * Get current bridge configuration.
     */
    sc->command   = pci_read_config(dev, PCIR_COMMAND, 1);
    sc->domain    = pci_get_domain(dev);
    sc->pribus    = pci_read_config(dev, PCIR_PRIBUS_1, 1);
    sc->secbus    = pci_read_config(dev, PCIR_SECBUS_1, 1);
    sc->subbus    = pci_read_config(dev, PCIR_SUBBUS_1, 1);
    sc->secstat   = pci_read_config(dev, PCIR_SECSTAT_1, 2);
    sc->bridgectl = pci_read_config(dev, PCIR_BRIDGECTL_1, 2);
    sc->seclat    = pci_read_config(dev, PCIR_SECLAT_1, 1);

    /*
     * Setup sysctl reporting nodes
     */
    sctx = device_get_sysctl_ctx(dev);
    soid = device_get_sysctl_tree(dev);
    SYSCTL_ADD_UINT(sctx, SYSCTL_CHILDREN(soid), OID_AUTO, "domain",
      CTLFLAG_RD, &sc->domain, 0, "Domain number");
    SYSCTL_ADD_UINT(sctx, SYSCTL_CHILDREN(soid), OID_AUTO, "pribus",
      CTLFLAG_RD, &sc->pribus, 0, "Primary bus number");
    SYSCTL_ADD_UINT(sctx, SYSCTL_CHILDREN(soid), OID_AUTO, "secbus",
      CTLFLAG_RD, &sc->secbus, 0, "Secondary bus number");
    SYSCTL_ADD_UINT(sctx, SYSCTL_CHILDREN(soid), OID_AUTO, "subbus",
      CTLFLAG_RD, &sc->subbus, 0, "Subordinate bus number");

#ifndef NEW_PCIB
    /*
     * Determine current I/O decode.
     */
    if (sc->command & PCIM_CMD_PORTEN) {
	iolow = pci_read_config(dev, PCIR_IOBASEL_1, 1);
	if ((iolow & PCIM_BRIO_MASK) == PCIM_BRIO_32) {
	    sc->iobase = PCI_PPBIOBASE(pci_read_config(dev, PCIR_IOBASEH_1, 2),
				       pci_read_config(dev, PCIR_IOBASEL_1, 1));
	} else {
	    sc->iobase = PCI_PPBIOBASE(0, pci_read_config(dev, PCIR_IOBASEL_1, 1));
	}

	iolow = pci_read_config(dev, PCIR_IOLIMITL_1, 1);
	if ((iolow & PCIM_BRIO_MASK) == PCIM_BRIO_32) {
	    sc->iolimit = PCI_PPBIOLIMIT(pci_read_config(dev, PCIR_IOLIMITH_1, 2),
					 pci_read_config(dev, PCIR_IOLIMITL_1, 1));
	} else {
	    sc->iolimit = PCI_PPBIOLIMIT(0, pci_read_config(dev, PCIR_IOLIMITL_1, 1));
	}
    }

    /*
     * Determine current memory decode.
     */
    if (sc->command & PCIM_CMD_MEMEN) {
	sc->membase   = PCI_PPBMEMBASE(0, pci_read_config(dev, PCIR_MEMBASE_1, 2));
	sc->memlimit  = PCI_PPBMEMLIMIT(0, pci_read_config(dev, PCIR_MEMLIMIT_1, 2));
	iolow = pci_read_config(dev, PCIR_PMBASEL_1, 1);
	if ((iolow & PCIM_BRPM_MASK) == PCIM_BRPM_64)
	    sc->pmembase = PCI_PPBMEMBASE(
		pci_read_config(dev, PCIR_PMBASEH_1, 4),
		pci_read_config(dev, PCIR_PMBASEL_1, 2));
	else
	    sc->pmembase = PCI_PPBMEMBASE(0,
		pci_read_config(dev, PCIR_PMBASEL_1, 2));
	iolow = pci_read_config(dev, PCIR_PMLIMITL_1, 1);
	if ((iolow & PCIM_BRPM_MASK) == PCIM_BRPM_64)	
	    sc->pmemlimit = PCI_PPBMEMLIMIT(
		pci_read_config(dev, PCIR_PMLIMITH_1, 4),
		pci_read_config(dev, PCIR_PMLIMITL_1, 2));
	else
	    sc->pmemlimit = PCI_PPBMEMLIMIT(0,
		pci_read_config(dev, PCIR_PMLIMITL_1, 2));
    }
#endif

    /*
     * Quirk handling.
     */
    switch (pci_get_devid(dev)) {
    case 0x12258086:		/* Intel 82454KX/GX (Orion) */
	{
	    uint8_t	supbus;

	    supbus = pci_read_config(dev, 0x41, 1);
	    if (supbus != 0xff) {
		sc->secbus = supbus + 1;
		sc->subbus = supbus + 1;
	    }
	    break;
	}

    /*
     * The i82380FB mobile docking controller is a PCI-PCI bridge,
     * and it is a subtractive bridge.  However, the ProgIf is wrong
     * so the normal setting of PCIB_SUBTRACTIVE bit doesn't
     * happen.  There's also a Toshiba bridge that behaves this
     * way.
     */
    case 0x124b8086:		/* Intel 82380FB Mobile */
    case 0x060513d7:		/* Toshiba ???? */
	sc->flags |= PCIB_SUBTRACTIVE;
	break;

#ifndef __rtems__
    /* Compaq R3000 BIOS sets wrong subordinate bus number. */
    case 0x00dd10de:
	{
	    char *cp;

	    if ((cp = getenv("smbios.planar.maker")) == NULL)
		break;
	    if (strncmp(cp, "Compal", 6) != 0) {
		freeenv(cp);
		break;
	    }
	    freeenv(cp);
	    if ((cp = getenv("smbios.planar.product")) == NULL)
		break;
	    if (strncmp(cp, "08A0", 4) != 0) {
		freeenv(cp);
		break;
	    }
	    freeenv(cp);
	    if (sc->subbus < 0xa) {
		pci_write_config(dev, PCIR_SUBBUS_1, 0xa, 1);
		sc->subbus = pci_read_config(dev, PCIR_SUBBUS_1, 1);
	    }
	    break;
	}
#endif /* __rtems__ */
    }

    if (pci_msi_device_blacklisted(dev))
	sc->flags |= PCIB_DISABLE_MSI;

    /*
     * Intel 815, 845 and other chipsets say they are PCI-PCI bridges,
     * but have a ProgIF of 0x80.  The 82801 family (AA, AB, BAM/CAM,
     * BA/CA/DB and E) PCI bridges are HUB-PCI bridges, in Intelese.
     * This means they act as if they were subtractively decoding
     * bridges and pass all transactions.  Mark them and real ProgIf 1
     * parts as subtractive.
     */
    if ((pci_get_devid(dev) & 0xff00ffff) == 0x24008086 ||
      pci_read_config(dev, PCIR_PROGIF, 1) == PCIP_BRIDGE_PCI_SUBTRACTIVE)
	sc->flags |= PCIB_SUBTRACTIVE;

#ifdef NEW_PCIB
    pcib_probe_windows(sc);
#endif
    if (bootverbose) {
	device_printf(dev, "  domain            %d\n", sc->domain);
	device_printf(dev, "  secondary bus     %d\n", sc->secbus);
	device_printf(dev, "  subordinate bus   %d\n", sc->subbus);
#ifdef NEW_PCIB
	if (pcib_is_window_open(&sc->io))
	    device_printf(dev, "  I/O decode        0x%jx-0x%jx\n",
	      (uintmax_t)sc->io.base, (uintmax_t)sc->io.limit);
	if (pcib_is_window_open(&sc->mem))
	    device_printf(dev, "  memory decode     0x%jx-0x%jx\n",
	      (uintmax_t)sc->mem.base, (uintmax_t)sc->mem.limit);
	if (pcib_is_window_open(&sc->pmem))
	    device_printf(dev, "  prefetched decode 0x%jx-0x%jx\n",
	      (uintmax_t)sc->pmem.base, (uintmax_t)sc->pmem.limit);
#else
	if (pcib_is_io_open(sc))
	    device_printf(dev, "  I/O decode        0x%x-0x%x\n",
	      sc->iobase, sc->iolimit);
	if (pcib_is_nonprefetch_open(sc))
	    device_printf(dev, "  memory decode     0x%jx-0x%jx\n",
	      (uintmax_t)sc->membase, (uintmax_t)sc->memlimit);
	if (pcib_is_prefetch_open(sc))
	    device_printf(dev, "  prefetched decode 0x%jx-0x%jx\n",
	      (uintmax_t)sc->pmembase, (uintmax_t)sc->pmemlimit);
#endif
	else
	    device_printf(dev, "  no prefetched decode\n");
	if (sc->flags & PCIB_SUBTRACTIVE)
	    device_printf(dev, "  Subtractively decoded bridge.\n");
    }

    /*
     * XXX If the secondary bus number is zero, we should assign a bus number
     *     since the BIOS hasn't, then initialise the bridge.  A simple
     *     bus_alloc_resource with the a couple of busses seems like the right
     *     approach, but we don't know what busses the BIOS might have already
     *     assigned to other bridges on this bus that probe later than we do.
     *
     *     If the subordinate bus number is less than the secondary bus number,
     *     we should pick a better value.  One sensible alternative would be to
     *     pick 255; the only tradeoff here is that configuration transactions
     *     would be more widely routed than absolutely necessary.  We could
     *     then do a walk of the tree later and fix it.
     */

    /*
     * Always enable busmastering on bridges so that transactions
     * initiated on the secondary bus are passed through to the
     * primary bus.
     */
    pci_enable_busmaster(dev);
}

int
pcib_attach(device_t dev)
{
    struct pcib_softc	*sc;
    device_t		child;

    pcib_attach_common(dev);
    sc = device_get_softc(dev);
    if (sc->secbus != 0) {
	child = device_add_child(dev, "pci", sc->secbus);
	if (child != NULL)
	    return(bus_generic_attach(dev));
    }

    /* no secondary bus; we should have fixed this */
    return(0);
}

int
pcib_read_ivar(device_t dev, device_t child, int which, uintptr_t *result)
{
    struct pcib_softc	*sc = device_get_softc(dev);
    
    switch (which) {
    case PCIB_IVAR_DOMAIN:
	*result = sc->domain;
	return(0);
    case PCIB_IVAR_BUS:
	*result = sc->secbus;
	return(0);
    }
    return(ENOENT);
}

int
pcib_write_ivar(device_t dev, device_t child, int which, uintptr_t value)
{
    struct pcib_softc	*sc = device_get_softc(dev);

    switch (which) {
    case PCIB_IVAR_DOMAIN:
	return(EINVAL);
    case PCIB_IVAR_BUS:
	sc->secbus = value;
	return(0);
    }
    return(ENOENT);
}

#ifdef NEW_PCIB
static const char *
pcib_child_name(device_t child)
{
	static char buf[64];

	if (device_get_nameunit(child) != NULL)
		return (device_get_nameunit(child));
	snprintf(buf, sizeof(buf), "pci%d:%d:%d:%d", pci_get_domain(child),
	    pci_get_bus(child), pci_get_slot(child), pci_get_function(child));
	return (buf);
}

/*
 * Attempt to allocate a resource from the existing resources assigned
 * to a window.
 */
static struct resource *
pcib_suballoc_resource(struct pcib_softc *sc, struct pcib_window *w,
    device_t child, int type, int *rid, u_long start, u_long end, u_long count,
    u_int flags)
{
	struct resource *res;

	if (!pcib_is_window_open(w))
		return (NULL);

	res = rman_reserve_resource(&w->rman, start, end, count,
	    flags & ~RF_ACTIVE, child);
	if (res == NULL)
		return (NULL);

	if (bootverbose)
		device_printf(sc->dev,
		    "allocated %s range (%#lx-%#lx) for rid %x of %s\n",
		    w->name, rman_get_start(res), rman_get_end(res), *rid,
		    pcib_child_name(child));
	rman_set_rid(res, *rid);

	/*
	 * If the resource should be active, pass that request up the
	 * tree.  This assumes the parent drivers can handle
	 * activating sub-allocated resources.
	 */
	if (flags & RF_ACTIVE) {
		if (bus_activate_resource(child, type, *rid, res) != 0) {
			rman_release_resource(res);
			return (NULL);
		}
	}

	return (res);
}

/*
 * Attempt to grow a window to make room for a given resource request.
 * The 'step' parameter is log_2 of the desired I/O window's alignment.
 */
static int
pcib_grow_window(struct pcib_softc *sc, struct pcib_window *w, int type,
    u_long start, u_long end, u_long count, u_int flags)
{
	u_long align, start_free, end_free, front, back, wmask;
	int error, rid;

	/*
	 * Clamp the desired resource range to the maximum address
	 * this window supports.  Reject impossible requests.
	 */
	if (!w->valid)
		return (EINVAL);
	if (end > w->rman.rm_end)
		end = w->rman.rm_end;
	if (start + count - 1 > end || start + count < start)
		return (EINVAL);
	wmask = (1ul << w->step) - 1;

	/*
	 * If there is no resource at all, just try to allocate enough
	 * aligned space for this resource.
	 */
	if (w->res == NULL) {
		if (RF_ALIGNMENT(flags) < w->step) {
			flags &= ~RF_ALIGNMENT_MASK;
			flags |= RF_ALIGNMENT_LOG2(w->step);
		}
		start &= ~wmask;
		end |= wmask;
		count = roundup2(count, 1ul << w->step);
		rid = w->reg;
		w->res = bus_alloc_resource(sc->dev, type, &rid, start, end,
		    count, flags & ~RF_ACTIVE);
		if (w->res == NULL) {
			if (bootverbose)
				device_printf(sc->dev,
		    "failed to allocate initial %s window (%#lx-%#lx,%#lx)\n",
				    w->name, start, end, count);
			return (ENXIO);
		}
		if (bootverbose)
			device_printf(sc->dev,
			    "allocated initial %s window of %#lx-%#lx\n",
			    w->name, rman_get_start(w->res),
			    rman_get_end(w->res));
		error = rman_manage_region(&w->rman, rman_get_start(w->res),
		    rman_get_end(w->res));
		if (error) {
			if (bootverbose)
				device_printf(sc->dev,
				    "failed to add initial %s window to rman\n",
				    w->name);
			bus_release_resource(sc->dev, type, w->reg, w->res);
			w->res = NULL;
			return (error);
		}
		pcib_activate_window(sc, type);
		goto updatewin;
	}

	/*
	 * See if growing the window would help.  Compute the minimum
	 * amount of address space needed on both the front and back
	 * ends of the existing window to satisfy the allocation.
	 *
	 * For each end, build a candidate region adjusting for the
	 * required alignment, etc.  If there is a free region at the
	 * edge of the window, grow from the inner edge of the free
	 * region.  Otherwise grow from the window boundary.
	 *
	 * XXX: Special case: if w->res is completely empty and the
	 * request size is larger than w->res, we should find the
	 * optimal aligned buffer containing w->res and allocate that.
	 */
	if (bootverbose)
		device_printf(sc->dev,
		    "attempting to grow %s window for (%#lx-%#lx,%#lx)\n",
		    w->name, start, end, count);
	align = 1ul << RF_ALIGNMENT(flags);
	if (start < rman_get_start(w->res)) {
		if (rman_first_free_region(&w->rman, &start_free, &end_free) !=
		    0 || start_free != rman_get_start(w->res))
			end_free = rman_get_start(w->res);
		if (end_free > end)
			end_free = end + 1;

		/* Move end_free down until it is properly aligned. */
		end_free &= ~(align - 1);
		end_free--;
		front = end_free - (count - 1);

		/*
		 * The resource would now be allocated at (front,
		 * end_free).  Ensure that fits in the (start, end)
		 * bounds.  end_free is checked above.  If 'front' is
		 * ok, ensure it is properly aligned for this window.
		 * Also check for underflow.
		 */
		if (front >= start && front <= end_free) {
			if (bootverbose)
				printf("\tfront candidate range: %#lx-%#lx\n",
				    front, end_free);
			front &= ~wmask;
			front = rman_get_start(w->res) - front;
		} else
			front = 0;
	} else
		front = 0;
	if (end > rman_get_end(w->res)) {
		if (rman_last_free_region(&w->rman, &start_free, &end_free) !=
		    0 || end_free != rman_get_end(w->res))
			start_free = rman_get_end(w->res) + 1;
		if (start_free < start)
			start_free = start;

		/* Move start_free up until it is properly aligned. */
		start_free = roundup2(start_free, align);
		back = start_free + count - 1;

		/*
		 * The resource would now be allocated at (start_free,
		 * back).  Ensure that fits in the (start, end)
		 * bounds.  start_free is checked above.  If 'back' is
		 * ok, ensure it is properly aligned for this window.
		 * Also check for overflow.
		 */
		if (back <= end && start_free <= back) {
			if (bootverbose)
				printf("\tback candidate range: %#lx-%#lx\n",
				    start_free, back);
			back |= wmask;
			back -= rman_get_end(w->res);
		} else
			back = 0;
	} else
		back = 0;

	/*
	 * Try to allocate the smallest needed region first.
	 * If that fails, fall back to the other region.
	 */
	error = ENOSPC;
	while (front != 0 || back != 0) {
		if (front != 0 && (front <= back || back == 0)) {
			error = bus_adjust_resource(sc->dev, type, w->res,
			    rman_get_start(w->res) - front,
			    rman_get_end(w->res));
			if (error == 0)
				break;
			front = 0;
		} else {
			error = bus_adjust_resource(sc->dev, type, w->res,
			    rman_get_start(w->res),
			    rman_get_end(w->res) + back);
			if (error == 0)
				break;
			back = 0;
		}
	}

	if (error)
		return (error);
	if (bootverbose)
		device_printf(sc->dev, "grew %s window to %#lx-%#lx\n",
		    w->name, rman_get_start(w->res), rman_get_end(w->res));

	/* Add the newly allocated region to the resource manager. */
	if (w->base != rman_get_start(w->res)) {
		KASSERT(w->limit == rman_get_end(w->res), ("both ends moved"));
		error = rman_manage_region(&w->rman, rman_get_start(w->res),
		    w->base - 1);
	} else {
		KASSERT(w->limit != rman_get_end(w->res),
		    ("neither end moved"));
		error = rman_manage_region(&w->rman, w->limit + 1,
		    rman_get_end(w->res));
	}
	if (error) {
		if (bootverbose)
			device_printf(sc->dev,
			    "failed to expand %s resource manager\n", w->name);
		bus_adjust_resource(sc->dev, type, w->res, w->base, w->limit);
		return (error);
	}

updatewin:
	/* Save the new window. */
	w->base = rman_get_start(w->res);
	w->limit = rman_get_end(w->res);
	KASSERT((w->base & wmask) == 0, ("start address is not aligned"));
	KASSERT((w->limit & wmask) == wmask, ("end address is not aligned"));
	pcib_write_windows(sc, w->mask);
	return (0);
}

/*
 * We have to trap resource allocation requests and ensure that the bridge
 * is set up to, or capable of handling them.
 */
struct resource *
pcib_alloc_resource(device_t dev, device_t child, int type, int *rid,
    u_long start, u_long end, u_long count, u_int flags)
{
	struct pcib_softc *sc;
	struct resource *r;

	sc = device_get_softc(dev);

	/*
	 * VGA resources are decoded iff the VGA enable bit is set in
	 * the bridge control register.  VGA resources do not fall into
	 * the resource windows and are passed up to the parent.
	 */
	if ((type == SYS_RES_IOPORT && pci_is_vga_ioport_range(start, end)) ||
	    (type == SYS_RES_MEMORY && pci_is_vga_memory_range(start, end))) {
		if (sc->bridgectl & PCIB_BCR_VGA_ENABLE)
			return (bus_generic_alloc_resource(dev, child, type,
			    rid, start, end, count, flags));
		else
			return (NULL);
	}

	switch (type) {
	case SYS_RES_IOPORT:
		r = pcib_suballoc_resource(sc, &sc->io, child, type, rid, start,
		    end, count, flags);
		if (r != NULL || (sc->flags & PCIB_SUBTRACTIVE) != 0)
			break;
		if (pcib_grow_window(sc, &sc->io, type, start, end, count,
		    flags) == 0)
			r = pcib_suballoc_resource(sc, &sc->io, child, type,
			    rid, start, end, count, flags);
		break;
	case SYS_RES_MEMORY:
		/*
		 * For prefetchable resources, prefer the prefetchable
		 * memory window, but fall back to the regular memory
		 * window if that fails.  Try both windows before
		 * attempting to grow a window in case the firmware
		 * has used a range in the regular memory window to
		 * map a prefetchable BAR.
		 */
		if (flags & RF_PREFETCHABLE) {
			r = pcib_suballoc_resource(sc, &sc->pmem, child, type,
			    rid, start, end, count, flags);
			if (r != NULL)
				break;
		}
		r = pcib_suballoc_resource(sc, &sc->mem, child, type, rid,
		    start, end, count, flags);
		if (r != NULL || (sc->flags & PCIB_SUBTRACTIVE) != 0)
			break;
		if (flags & RF_PREFETCHABLE) {
			if (pcib_grow_window(sc, &sc->pmem, type, start, end,
			    count, flags) == 0) {
				r = pcib_suballoc_resource(sc, &sc->pmem, child,
				    type, rid, start, end, count, flags);
				if (r != NULL)
					break;
			}
		}
		if (pcib_grow_window(sc, &sc->mem, type, start, end, count,
		    flags & ~RF_PREFETCHABLE) == 0)
			r = pcib_suballoc_resource(sc, &sc->mem, child, type,
			    rid, start, end, count, flags);
		break;
	default:
		return (bus_generic_alloc_resource(dev, child, type, rid,
		    start, end, count, flags));
	}

	/*
	 * If attempts to suballocate from the window fail but this is a
	 * subtractive bridge, pass the request up the tree.
	 */
	if (sc->flags & PCIB_SUBTRACTIVE && r == NULL)
		return (bus_generic_alloc_resource(dev, child, type, rid,
		    start, end, count, flags));
	return (r);
}

int
pcib_adjust_resource(device_t bus, device_t child, int type, struct resource *r,
    u_long start, u_long end)
{
	struct pcib_softc *sc;

	sc = device_get_softc(bus);
	if (pcib_is_resource_managed(sc, type, r))
		return (rman_adjust_resource(r, start, end));
	return (bus_generic_adjust_resource(bus, child, type, r, start, end));
}

int
pcib_release_resource(device_t dev, device_t child, int type, int rid,
    struct resource *r)
{
	struct pcib_softc *sc;
	int error;

	sc = device_get_softc(dev);
	if (pcib_is_resource_managed(sc, type, r)) {
		if (rman_get_flags(r) & RF_ACTIVE) {
			error = bus_deactivate_resource(child, type, rid, r);
			if (error)
				return (error);
		}
		return (rman_release_resource(r));
	}
	return (bus_generic_release_resource(dev, child, type, rid, r));
}
#else
/*
 * We have to trap resource allocation requests and ensure that the bridge
 * is set up to, or capable of handling them.
 */
struct resource *
pcib_alloc_resource(device_t dev, device_t child, int type, int *rid, 
    u_long start, u_long end, u_long count, u_int flags)
{
	struct pcib_softc	*sc = device_get_softc(dev);
	const char *name, *suffix;
	int ok;

	/*
	 * Fail the allocation for this range if it's not supported.
	 */
	name = device_get_nameunit(child);
	if (name == NULL) {
		name = "";
		suffix = "";
	} else
		suffix = " ";
	switch (type) {
	case SYS_RES_IOPORT:
		ok = 0;
		if (!pcib_is_io_open(sc))
			break;
		ok = (start >= sc->iobase && end <= sc->iolimit);

		/*
		 * Make sure we allow access to VGA I/O addresses when the
		 * bridge has the "VGA Enable" bit set.
		 */
		if (!ok && pci_is_vga_ioport_range(start, end))
			ok = (sc->bridgectl & PCIB_BCR_VGA_ENABLE) ? 1 : 0;

		if ((sc->flags & PCIB_SUBTRACTIVE) == 0) {
			if (!ok) {
				if (start < sc->iobase)
					start = sc->iobase;
				if (end > sc->iolimit)
					end = sc->iolimit;
				if (start < end)
					ok = 1;
			}
		} else {
			ok = 1;
#if 0
			/*
			 * If we overlap with the subtractive range, then
			 * pick the upper range to use.
			 */
			if (start < sc->iolimit && end > sc->iobase)
				start = sc->iolimit + 1;
#endif
		}
		if (end < start) {
			device_printf(dev, "ioport: end (%lx) < start (%lx)\n",
			    end, start);
			start = 0;
			end = 0;
			ok = 0;
		}
		if (!ok) {
			device_printf(dev, "%s%srequested unsupported I/O "
			    "range 0x%lx-0x%lx (decoding 0x%x-0x%x)\n",
			    name, suffix, start, end, sc->iobase, sc->iolimit);
			return (NULL);
		}
		if (bootverbose)
			device_printf(dev,
			    "%s%srequested I/O range 0x%lx-0x%lx: in range\n",
			    name, suffix, start, end);
		break;

	case SYS_RES_MEMORY:
		ok = 0;
		if (pcib_is_nonprefetch_open(sc))
			ok = ok || (start >= sc->membase && end <= sc->memlimit);
		if (pcib_is_prefetch_open(sc))
			ok = ok || (start >= sc->pmembase && end <= sc->pmemlimit);

		/*
		 * Make sure we allow access to VGA memory addresses when the
		 * bridge has the "VGA Enable" bit set.
		 */
		if (!ok && pci_is_vga_memory_range(start, end))
			ok = (sc->bridgectl & PCIB_BCR_VGA_ENABLE) ? 1 : 0;

		if ((sc->flags & PCIB_SUBTRACTIVE) == 0) {
			if (!ok) {
				ok = 1;
				if (flags & RF_PREFETCHABLE) {
					if (pcib_is_prefetch_open(sc)) {
						if (start < sc->pmembase)
							start = sc->pmembase;
						if (end > sc->pmemlimit)
							end = sc->pmemlimit;
					} else {
						ok = 0;
					}
				} else {	/* non-prefetchable */
					if (pcib_is_nonprefetch_open(sc)) {
						if (start < sc->membase)
							start = sc->membase;
						if (end > sc->memlimit)
							end = sc->memlimit;
					} else {
						ok = 0;
					}
				}
			}
		} else if (!ok) {
			ok = 1;	/* subtractive bridge: always ok */
#if 0
			if (pcib_is_nonprefetch_open(sc)) {
				if (start < sc->memlimit && end > sc->membase)
					start = sc->memlimit + 1;
			}
			if (pcib_is_prefetch_open(sc)) {
				if (start < sc->pmemlimit && end > sc->pmembase)
					start = sc->pmemlimit + 1;
			}
#endif
		}
		if (end < start) {
			device_printf(dev, "memory: end (%lx) < start (%lx)\n",
			    end, start);
			start = 0;
			end = 0;
			ok = 0;
		}
		if (!ok && bootverbose)
			device_printf(dev,
			    "%s%srequested unsupported memory range %#lx-%#lx "
			    "(decoding %#jx-%#jx, %#jx-%#jx)\n",
			    name, suffix, start, end,
			    (uintmax_t)sc->membase, (uintmax_t)sc->memlimit,
			    (uintmax_t)sc->pmembase, (uintmax_t)sc->pmemlimit);
		if (!ok)
			return (NULL);
		if (bootverbose)
			device_printf(dev,"%s%srequested memory range "
			    "0x%lx-0x%lx: good\n",
			    name, suffix, start, end);
		break;

	default:
		break;
	}
	/*
	 * Bridge is OK decoding this resource, so pass it up.
	 */
	return (bus_generic_alloc_resource(dev, child, type, rid, start, end,
	    count, flags));
}
#endif

/*
 * PCIB interface.
 */
int
pcib_maxslots(device_t dev)
{
    return(PCI_SLOTMAX);
}

/*
 * Since we are a child of a PCI bus, its parent must support the pcib interface.
 */
uint32_t
pcib_read_config(device_t dev, u_int b, u_int s, u_int f, u_int reg, int width)
{
    return(PCIB_READ_CONFIG(device_get_parent(device_get_parent(dev)), b, s, f, reg, width));
}

void
pcib_write_config(device_t dev, u_int b, u_int s, u_int f, u_int reg, uint32_t val, int width)
{
    PCIB_WRITE_CONFIG(device_get_parent(device_get_parent(dev)), b, s, f, reg, val, width);
}

/*
 * Route an interrupt across a PCI bridge.
 */
int
pcib_route_interrupt(device_t pcib, device_t dev, int pin)
{
    device_t	bus;
    int		parent_intpin;
    int		intnum;

    /*	
     *
     * The PCI standard defines a swizzle of the child-side device/intpin to
     * the parent-side intpin as follows.
     *
     * device = device on child bus
     * child_intpin = intpin on child bus slot (0-3)
     * parent_intpin = intpin on parent bus slot (0-3)
     *
     * parent_intpin = (device + child_intpin) % 4
     */
    parent_intpin = (pci_get_slot(dev) + (pin - 1)) % 4;

    /*
     * Our parent is a PCI bus.  Its parent must export the pcib interface
     * which includes the ability to route interrupts.
     */
    bus = device_get_parent(pcib);
    intnum = PCIB_ROUTE_INTERRUPT(device_get_parent(bus), pcib, parent_intpin + 1);
    if (PCI_INTERRUPT_VALID(intnum) && bootverbose) {
	device_printf(pcib, "slot %d INT%c is routed to irq %d\n",
	    pci_get_slot(dev), 'A' + pin - 1, intnum);
    }
    return(intnum);
}

/* Pass request to alloc MSI/MSI-X messages up to the parent bridge. */
int
pcib_alloc_msi(device_t pcib, device_t dev, int count, int maxcount, int *irqs)
{
	struct pcib_softc *sc = device_get_softc(pcib);
	device_t bus;

	if (sc->flags & PCIB_DISABLE_MSI)
		return (ENXIO);
	bus = device_get_parent(pcib);
	return (PCIB_ALLOC_MSI(device_get_parent(bus), dev, count, maxcount,
	    irqs));
}

/* Pass request to release MSI/MSI-X messages up to the parent bridge. */
int
pcib_release_msi(device_t pcib, device_t dev, int count, int *irqs)
{
	device_t bus;

	bus = device_get_parent(pcib);
	return (PCIB_RELEASE_MSI(device_get_parent(bus), dev, count, irqs));
}

/* Pass request to alloc an MSI-X message up to the parent bridge. */
int
pcib_alloc_msix(device_t pcib, device_t dev, int *irq)
{
	struct pcib_softc *sc = device_get_softc(pcib);
	device_t bus;

	if (sc->flags & PCIB_DISABLE_MSI)
		return (ENXIO);
	bus = device_get_parent(pcib);
	return (PCIB_ALLOC_MSIX(device_get_parent(bus), dev, irq));
}

/* Pass request to release an MSI-X message up to the parent bridge. */
int
pcib_release_msix(device_t pcib, device_t dev, int irq)
{
	device_t bus;

	bus = device_get_parent(pcib);
	return (PCIB_RELEASE_MSIX(device_get_parent(bus), dev, irq));
}

/* Pass request to map MSI/MSI-X message up to parent bridge. */
int
pcib_map_msi(device_t pcib, device_t dev, int irq, uint64_t *addr,
    uint32_t *data)
{
	device_t bus;
	int error;

	bus = device_get_parent(pcib);
	error = PCIB_MAP_MSI(device_get_parent(bus), dev, irq, addr, data);
	if (error)
		return (error);

	pci_ht_map_msi(pcib, *addr);
	return (0);
}

/*
 * Try to read the bus number of a host-PCI bridge using appropriate config
 * registers.
 */
int
host_pcib_get_busno(pci_read_config_fn read_config, int bus, int slot, int func,
    uint8_t *busnum)
{
	uint32_t id;

	id = read_config(bus, slot, func, PCIR_DEVVENDOR, 4);
	if (id == 0xffffffff)
		return (0);

	switch (id) {
	case 0x12258086:
		/* Intel 824?? */
		/* XXX This is a guess */
		/* *busnum = read_config(bus, slot, func, 0x41, 1); */
		*busnum = bus;
		break;
	case 0x84c48086:
		/* Intel 82454KX/GX (Orion) */
		*busnum = read_config(bus, slot, func, 0x4a, 1);
		break;
	case 0x84ca8086:
		/*
		 * For the 450nx chipset, there is a whole bundle of
		 * things pretending to be host bridges. The MIOC will 
		 * be seen first and isn't really a pci bridge (the
		 * actual busses are attached to the PXB's). We need to 
		 * read the registers of the MIOC to figure out the
		 * bus numbers for the PXB channels.
		 *
		 * Since the MIOC doesn't have a pci bus attached, we
		 * pretend it wasn't there.
		 */
		return (0);
	case 0x84cb8086:
		switch (slot) {
		case 0x12:
			/* Intel 82454NX PXB#0, Bus#A */
			*busnum = read_config(bus, 0x10, func, 0xd0, 1);
			break;
		case 0x13:
			/* Intel 82454NX PXB#0, Bus#B */
			*busnum = read_config(bus, 0x10, func, 0xd1, 1) + 1;
			break;
		case 0x14:
			/* Intel 82454NX PXB#1, Bus#A */
			*busnum = read_config(bus, 0x10, func, 0xd3, 1);
			break;
		case 0x15:
			/* Intel 82454NX PXB#1, Bus#B */
			*busnum = read_config(bus, 0x10, func, 0xd4, 1) + 1;
			break;
		}
		break;

		/* ServerWorks -- vendor 0x1166 */
	case 0x00051166:
	case 0x00061166:
	case 0x00081166:
	case 0x00091166:
	case 0x00101166:
	case 0x00111166:
	case 0x00171166:
	case 0x01011166:
	case 0x010f1014:
	case 0x01101166:
	case 0x02011166:
	case 0x02251166:
	case 0x03021014:
		*busnum = read_config(bus, slot, func, 0x44, 1);
		break;

		/* Compaq/HP -- vendor 0x0e11 */
	case 0x60100e11:
		*busnum = read_config(bus, slot, func, 0xc8, 1);
		break;
	default:
		/* Don't know how to read bus number. */
		return 0;
	}

	return 1;
}