xref: /freebsd/sys/dev/pci/pci_pci.c (revision 8b92ad4371b833058069b69a71e2295ea223f5e4)

/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * 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 "opt_pci.h"

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

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

#include "pcib_if.h"

static int		pcib_probe(device_t dev);
static int		pcib_suspend(device_t dev);
static int		pcib_resume(device_t dev);
static int		pcib_power_for_sleep(device_t pcib, device_t dev,
			    int *pstate);
static int		pcib_ari_get_id(device_t pcib, device_t dev,
    enum pci_id_type type, uintptr_t *id);
static uint32_t		pcib_read_config(device_t dev, u_int b, u_int s,
    u_int f, u_int reg, int width);
static void		pcib_write_config(device_t dev, u_int b, u_int s,
    u_int f, u_int reg, uint32_t val, int width);
static int		pcib_ari_maxslots(device_t dev);
static int		pcib_ari_maxfuncs(device_t dev);
static int		pcib_try_enable_ari(device_t pcib, device_t dev);
static int		pcib_ari_enabled(device_t pcib);
static void		pcib_ari_decode_rid(device_t pcib, uint16_t rid,
			    int *bus, int *slot, int *func);
#ifdef PCI_HP
static void		pcib_pcie_ab_timeout(void *arg);
static void		pcib_pcie_cc_timeout(void *arg);
static void		pcib_pcie_dll_timeout(void *arg);
#endif
static int		pcib_request_feature_default(device_t pcib, device_t dev,
			    enum pci_feature feature);

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

    /* Bus interface */
    DEVMETHOD(bus_child_present,	pcib_child_present),
    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_ari_maxslots),
    DEVMETHOD(pcib_maxfuncs,		pcib_ari_maxfuncs),
    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(pcib_power_for_sleep,	pcib_power_for_sleep),
    DEVMETHOD(pcib_get_id,		pcib_ari_get_id),
    DEVMETHOD(pcib_try_enable_ari,	pcib_try_enable_ari),
    DEVMETHOD(pcib_ari_enabled,		pcib_ari_enabled),
    DEVMETHOD(pcib_decode_rid,		pcib_ari_decode_rid),
    DEVMETHOD(pcib_request_feature,	pcib_request_feature_default),

    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, NULL, NULL);

#if defined(NEW_PCIB) || defined(PCI_HP)
SYSCTL_DECL(_hw_pci);
#endif

#ifdef NEW_PCIB
static int pci_clear_pcib;
SYSCTL_INT(_hw_pci, OID_AUTO, clear_pcib, CTLFLAG_RDTUN, &pci_clear_pcib, 0,
    "Clear firmware-assigned resources for PCI-PCI bridge I/O windows.");

/*
 * 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) {
#ifdef PCI_RES_BUS
	case PCI_RES_BUS:
		return (rman_is_region_manager(r, &sc->bus.rman));
#endif
	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);
	}
}

/*
 * This is used to reject I/O port allocations that conflict with an
 * ISA alias range.
 */
static int
pcib_is_isa_range(struct pcib_softc *sc, rman_res_t start, rman_res_t end,
    rman_res_t count)
{
	rman_res_t next_alias;

	if (!(sc->bridgectl & PCIB_BCR_ISA_ENABLE))
		return (0);

	/* Only check fixed ranges for overlap. */
	if (start + count - 1 != end)
		return (0);

	/* ISA aliases are only in the lower 64KB of I/O space. */
	if (start >= 65536)
		return (0);

	/* Check for overlap with 0x000 - 0x0ff as a special case. */
	if (start < 0x100)
		goto alias;

	/*
	 * If the start address is an alias, the range is an alias.
	 * Otherwise, compute the start of the next alias range and
	 * check if it is before the end of the candidate range.
	 */
	if ((start & 0x300) != 0)
		goto alias;
	next_alias = (start & ~0x3fful) | 0x100;
	if (next_alias <= end)
		goto alias;
	return (0);

alias:
	if (bootverbose)
		device_printf(sc->dev,
		    "I/O range %#jx-%#jx overlaps with an ISA alias\n", start,
		    end);
	return (1);
}

static void
pcib_add_window_resources(struct pcib_window *w, struct resource **res,
    int count)
{
	struct resource **newarray;
	int error, i;

	newarray = malloc(sizeof(struct resource *) * (w->count + count),
	    M_DEVBUF, M_WAITOK);
	if (w->res != NULL)
		bcopy(w->res, newarray, sizeof(struct resource *) * w->count);
	bcopy(res, newarray + w->count, sizeof(struct resource *) * count);
	free(w->res, M_DEVBUF);
	w->res = newarray;
	w->count += count;

	for (i = 0; i < count; i++) {
		error = rman_manage_region(&w->rman, rman_get_start(res[i]),
		    rman_get_end(res[i]));
		if (error)
			panic("Failed to add resource to rman");
	}
}

typedef void (nonisa_callback)(rman_res_t start, rman_res_t end, void *arg);

static void
pcib_walk_nonisa_ranges(rman_res_t start, rman_res_t end, nonisa_callback *cb,
    void *arg)
{
	rman_res_t next_end;

	/*
	 * If start is within an ISA alias range, move up to the start
	 * of the next non-alias range.  As a special case, addresses
	 * in the range 0x000 - 0x0ff should also be skipped since
	 * those are used for various system I/O devices in ISA
	 * systems.
	 */
	if (start <= 65535) {
		if (start < 0x100 || (start & 0x300) != 0) {
			start &= ~0x3ff;
			start += 0x400;
		}
	}

	/* ISA aliases are only in the lower 64KB of I/O space. */
	while (start <= MIN(end, 65535)) {
		next_end = MIN(start | 0xff, end);
		cb(start, next_end, arg);
		start += 0x400;
	}

	if (start <= end)
		cb(start, end, arg);
}

static void
count_ranges(rman_res_t start, rman_res_t end, void *arg)
{
	int *countp;

	countp = arg;
	(*countp)++;
}

struct alloc_state {
	struct resource **res;
	struct pcib_softc *sc;
	int count, error;
};

static void
alloc_ranges(rman_res_t start, rman_res_t end, void *arg)
{
	struct alloc_state *as;
	struct pcib_window *w;
	int rid;

	as = arg;
	if (as->error != 0)
		return;

	w = &as->sc->io;
	rid = w->reg;
	if (bootverbose)
		device_printf(as->sc->dev,
		    "allocating non-ISA range %#jx-%#jx\n", start, end);
	as->res[as->count] = bus_alloc_resource(as->sc->dev, SYS_RES_IOPORT,
	    &rid, start, end, end - start + 1, 0);
	if (as->res[as->count] == NULL)
		as->error = ENXIO;
	else
		as->count++;
}

static int
pcib_alloc_nonisa_ranges(struct pcib_softc *sc, rman_res_t start, rman_res_t end)
{
	struct alloc_state as;
	int i, new_count;

	/* First, see how many ranges we need. */
	new_count = 0;
	pcib_walk_nonisa_ranges(start, end, count_ranges, &new_count);

	/* Second, allocate the ranges. */
	as.res = malloc(sizeof(struct resource *) * new_count, M_DEVBUF,
	    M_WAITOK);
	as.sc = sc;
	as.count = 0;
	as.error = 0;
	pcib_walk_nonisa_ranges(start, end, alloc_ranges, &as);
	if (as.error != 0) {
		for (i = 0; i < as.count; i++)
			bus_release_resource(sc->dev, SYS_RES_IOPORT,
			    sc->io.reg, as.res[i]);
		free(as.res, M_DEVBUF);
		return (as.error);
	}
	KASSERT(as.count == new_count, ("%s: count mismatch", __func__));

	/* Third, add the ranges to the window. */
	pcib_add_window_resources(&sc->io, as.res, as.count);
	free(as.res, M_DEVBUF);
	return (0);
}

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

	if (max_address != (rman_res_t)max_address)
		max_address = ~0;
	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;
	}
	if (type == SYS_RES_IOPORT && sc->bridgectl & PCIB_BCR_ISA_ENABLE)
		(void)pcib_alloc_nonisa_ranges(sc, w->base, w->limit);
	else {
		rid = w->reg;
		res = bus_alloc_resource(sc->dev, type, &rid, w->base, w->limit,
		    w->limit - w->base + 1, flags);
		if (res != NULL)
			pcib_add_window_resources(w, &res, 1);
	}
	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);
}

/*
 * 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;

	if (pci_clear_pcib) {
		pcib_bridge_init(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);
	}
}

static void
pcib_release_window(struct pcib_softc *sc, struct pcib_window *w, int type)
{
	device_t dev;
	int error, i;

	if (!w->valid)
		return;

	dev = sc->dev;
	error = rman_fini(&w->rman);
	if (error) {
		device_printf(dev, "failed to release %s rman\n", w->name);
		return;
	}
	free(__DECONST(char *, w->rman.rm_descr), M_DEVBUF);

	for (i = 0; i < w->count; i++) {
		error = bus_free_resource(dev, type, w->res[i]);
		if (error)
			device_printf(dev,
			    "failed to release %s resource: %d\n", w->name,
			    error);
	}
	free(w->res, M_DEVBUF);
}

static void
pcib_free_windows(struct pcib_softc *sc)
{

	pcib_release_window(sc, &sc->pmem, SYS_RES_MEMORY);
	pcib_release_window(sc, &sc->mem, SYS_RES_MEMORY);
	pcib_release_window(sc, &sc->io, SYS_RES_IOPORT);
}

#ifdef PCI_RES_BUS
/*
 * Allocate a suitable secondary bus for this bridge if needed and
 * initialize the resource manager for the secondary bus range.  Note
 * that the minimum count is a desired value and this may allocate a
 * smaller range.
 */
void
pcib_setup_secbus(device_t dev, struct pcib_secbus *bus, int min_count)
{
	char buf[64];
	int error, rid, sec_reg;

	switch (pci_read_config(dev, PCIR_HDRTYPE, 1) & PCIM_HDRTYPE) {
	case PCIM_HDRTYPE_BRIDGE:
		sec_reg = PCIR_SECBUS_1;
		bus->sub_reg = PCIR_SUBBUS_1;
		break;
	case PCIM_HDRTYPE_CARDBUS:
		sec_reg = PCIR_SECBUS_2;
		bus->sub_reg = PCIR_SUBBUS_2;
		break;
	default:
		panic("not a PCI bridge");
	}
	bus->sec = pci_read_config(dev, sec_reg, 1);
	bus->sub = pci_read_config(dev, bus->sub_reg, 1);
	bus->dev = dev;
	bus->rman.rm_start = 0;
	bus->rman.rm_end = PCI_BUSMAX;
	bus->rman.rm_type = RMAN_ARRAY;
	snprintf(buf, sizeof(buf), "%s bus numbers", device_get_nameunit(dev));
	bus->rman.rm_descr = strdup(buf, M_DEVBUF);
	error = rman_init(&bus->rman);
	if (error)
		panic("Failed to initialize %s bus number rman",
		    device_get_nameunit(dev));

	/*
	 * Allocate a bus range.  This will return an existing bus range
	 * if one exists, or a new bus range if one does not.
	 */
	rid = 0;
	bus->res = bus_alloc_resource_anywhere(dev, PCI_RES_BUS, &rid,
	    min_count, 0);
	if (bus->res == NULL) {
		/*
		 * Fall back to just allocating a range of a single bus
		 * number.
		 */
		bus->res = bus_alloc_resource_anywhere(dev, PCI_RES_BUS, &rid,
		    1, 0);
	} else if (rman_get_size(bus->res) < min_count)
		/*
		 * Attempt to grow the existing range to satisfy the
		 * minimum desired count.
		 */
		(void)bus_adjust_resource(dev, PCI_RES_BUS, bus->res,
		    rman_get_start(bus->res), rman_get_start(bus->res) +
		    min_count - 1);

	/*
	 * Add the initial resource to the rman.
	 */
	if (bus->res != NULL) {
		error = rman_manage_region(&bus->rman, rman_get_start(bus->res),
		    rman_get_end(bus->res));
		if (error)
			panic("Failed to add resource to rman");
		bus->sec = rman_get_start(bus->res);
		bus->sub = rman_get_end(bus->res);
	}
}

void
pcib_free_secbus(device_t dev, struct pcib_secbus *bus)
{
	int error;

	error = rman_fini(&bus->rman);
	if (error) {
		device_printf(dev, "failed to release bus number rman\n");
		return;
	}
	free(__DECONST(char *, bus->rman.rm_descr), M_DEVBUF);

	error = bus_free_resource(dev, PCI_RES_BUS, bus->res);
	if (error)
		device_printf(dev,
		    "failed to release bus numbers resource: %d\n", error);
}

static struct resource *
pcib_suballoc_bus(struct pcib_secbus *bus, device_t child, int *rid,
    rman_res_t start, rman_res_t end, rman_res_t count, u_int flags)
{
	struct resource *res;

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

	if (bootverbose)
		device_printf(bus->dev,
		    "allocated bus range (%ju-%ju) for rid %d of %s\n",
		    rman_get_start(res), rman_get_end(res), *rid,
		    pcib_child_name(child));
	rman_set_rid(res, *rid);
	return (res);
}

/*
 * Attempt to grow the secondary bus range.  This is much simpler than
 * for I/O windows as the range can only be grown by increasing
 * subbus.
 */
static int
pcib_grow_subbus(struct pcib_secbus *bus, rman_res_t new_end)
{
	rman_res_t old_end;
	int error;

	old_end = rman_get_end(bus->res);
	KASSERT(new_end > old_end, ("attempt to shrink subbus"));
	error = bus_adjust_resource(bus->dev, PCI_RES_BUS, bus->res,
	    rman_get_start(bus->res), new_end);
	if (error)
		return (error);
	if (bootverbose)
		device_printf(bus->dev, "grew bus range to %ju-%ju\n",
		    rman_get_start(bus->res), rman_get_end(bus->res));
	error = rman_manage_region(&bus->rman, old_end + 1,
	    rman_get_end(bus->res));
	if (error)
		panic("Failed to add resource to rman");
	bus->sub = rman_get_end(bus->res);
	pci_write_config(bus->dev, bus->sub_reg, bus->sub, 1);
	return (0);
}

struct resource *
pcib_alloc_subbus(struct pcib_secbus *bus, device_t child, int *rid,
    rman_res_t start, rman_res_t end, rman_res_t count, u_int flags)
{
	struct resource *res;
	rman_res_t start_free, end_free, new_end;

	/*
	 * First, see if the request can be satisified by the existing
	 * bus range.
	 */
	res = pcib_suballoc_bus(bus, child, rid, start, end, count, flags);
	if (res != NULL)
		return (res);

	/*
	 * Figure out a range to grow the bus range.  First, find the
	 * first bus number after the last allocated bus in the rman and
	 * enforce that as a minimum starting point for the range.
	 */
	if (rman_last_free_region(&bus->rman, &start_free, &end_free) != 0 ||
	    end_free != bus->sub)
		start_free = bus->sub + 1;
	if (start_free < start)
		start_free = start;
	new_end = start_free + count - 1;

	/*
	 * See if this new range would satisfy the request if it
	 * succeeds.
	 */
	if (new_end > end)
		return (NULL);

	/* Finally, attempt to grow the existing resource. */
	if (bootverbose) {
		device_printf(bus->dev,
		    "attempting to grow bus range for %ju buses\n", count);
		printf("\tback candidate range: %ju-%ju\n", start_free,
		    new_end);
	}
	if (pcib_grow_subbus(bus, new_end) == 0)
		return (pcib_suballoc_bus(bus, child, rid, start, end, count,
		    flags));
	return (NULL);
}
#endif

#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);
}

/*
 * Get current I/O decode.
 */
static void
pcib_get_io_decode(struct pcib_softc *sc)
{
	device_t	dev;
	uint32_t	iolow;

	dev = sc->dev;

	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), iolow);
	else
		sc->iobase = PCI_PPBIOBASE(0, iolow);

	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), iolow);
	else
		sc->iolimit = PCI_PPBIOLIMIT(0, iolow);
}

/*
 * Get current memory decode.
 */
static void
pcib_get_mem_decode(struct pcib_softc *sc)
{
	device_t	dev;
	pci_addr_t	pmemlow;

	dev = sc->dev;

	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));

	pmemlow = pci_read_config(dev, PCIR_PMBASEL_1, 2);
	if ((pmemlow & PCIM_BRPM_MASK) == PCIM_BRPM_64)
		sc->pmembase = PCI_PPBMEMBASE(
		    pci_read_config(dev, PCIR_PMBASEH_1, 4), pmemlow);
	else
		sc->pmembase = PCI_PPBMEMBASE(0, pmemlow);

	pmemlow = pci_read_config(dev, PCIR_PMLIMITL_1, 2);
	if ((pmemlow & PCIM_BRPM_MASK) == PCIM_BRPM_64)
		sc->pmemlimit = PCI_PPBMEMLIMIT(
		    pci_read_config(dev, PCIR_PMLIMITH_1, 4), pmemlow);
	else
		sc->pmemlimit = PCI_PPBMEMLIMIT(0, pmemlow);
}

/*
 * Restore previous I/O decode.
 */
static void
pcib_set_io_decode(struct pcib_softc *sc)
{
	device_t	dev;
	uint32_t	iohi;

	dev = sc->dev;

	iohi = sc->iobase >> 16;
	if (iohi > 0)
		pci_write_config(dev, PCIR_IOBASEH_1, iohi, 2);
	pci_write_config(dev, PCIR_IOBASEL_1, sc->iobase >> 8, 1);

	iohi = sc->iolimit >> 16;
	if (iohi > 0)
		pci_write_config(dev, PCIR_IOLIMITH_1, iohi, 2);
	pci_write_config(dev, PCIR_IOLIMITL_1, sc->iolimit >> 8, 1);
}

/*
 * Restore previous memory decode.
 */
static void
pcib_set_mem_decode(struct pcib_softc *sc)
{
	device_t	dev;
	pci_addr_t	pmemhi;

	dev = sc->dev;

	pci_write_config(dev, PCIR_MEMBASE_1, sc->membase >> 16, 2);
	pci_write_config(dev, PCIR_MEMLIMIT_1, sc->memlimit >> 16, 2);

	pmemhi = sc->pmembase >> 32;
	if (pmemhi > 0)
		pci_write_config(dev, PCIR_PMBASEH_1, pmemhi, 4);
	pci_write_config(dev, PCIR_PMBASEL_1, sc->pmembase >> 16, 2);

	pmemhi = sc->pmemlimit >> 32;
	if (pmemhi > 0)
		pci_write_config(dev, PCIR_PMLIMITH_1, pmemhi, 4);
	pci_write_config(dev, PCIR_PMLIMITL_1, sc->pmemlimit >> 16, 2);
}
#endif

#ifdef PCI_HP
/*
 * PCI-express HotPlug support.
 */
static int pci_enable_pcie_hp = 1;
SYSCTL_INT(_hw_pci, OID_AUTO, enable_pcie_hp, CTLFLAG_RDTUN,
    &pci_enable_pcie_hp, 0,
    "Enable support for native PCI-express HotPlug.");

static void
pcib_probe_hotplug(struct pcib_softc *sc)
{
	device_t dev;
	uint32_t link_cap;
	uint16_t link_sta, slot_sta;

	if (!pci_enable_pcie_hp)
		return;

	dev = sc->dev;
	if (pci_find_cap(dev, PCIY_EXPRESS, NULL) != 0)
		return;

	if (!(pcie_read_config(dev, PCIER_FLAGS, 2) & PCIEM_FLAGS_SLOT))
		return;

	sc->pcie_slot_cap = pcie_read_config(dev, PCIER_SLOT_CAP, 4);

	if ((sc->pcie_slot_cap & PCIEM_SLOT_CAP_HPC) == 0)
		return;
	link_cap = pcie_read_config(dev, PCIER_LINK_CAP, 4);
	if ((link_cap & PCIEM_LINK_CAP_DL_ACTIVE) == 0)
		return;

	/*
	 * Some devices report that they have an MRL when they actually
	 * do not.  Since they always report that the MRL is open, child
	 * devices would be ignored.  Try to detect these devices and
	 * ignore their claim of HotPlug support.
	 *
	 * If there is an open MRL but the Data Link Layer is active,
	 * the MRL is not real.
	 */
	if ((sc->pcie_slot_cap & PCIEM_SLOT_CAP_MRLSP) != 0) {
		link_sta = pcie_read_config(dev, PCIER_LINK_STA, 2);
		slot_sta = pcie_read_config(dev, PCIER_SLOT_STA, 2);
		if ((slot_sta & PCIEM_SLOT_STA_MRLSS) != 0 &&
		    (link_sta & PCIEM_LINK_STA_DL_ACTIVE) != 0) {
			return;
		}
	}

	/*
	 * Now that we're sure we want to do hot plug, ask the
	 * firmware, if any, if that's OK.
	 */
	if (pcib_request_feature(dev, PCI_FEATURE_HP) != 0) {
		if (bootverbose)
			device_printf(dev, "Unable to activate hot plug feature.\n");
		return;
	}

	sc->flags |= PCIB_HOTPLUG;
}

/*
 * Send a HotPlug command to the slot control register.  If this slot
 * uses command completion interrupts and a previous command is still
 * in progress, then the command is dropped.  Once the previous
 * command completes or times out, pcib_pcie_hotplug_update() will be
 * invoked to post a new command based on the slot's state at that
 * time.
 */
static void
pcib_pcie_hotplug_command(struct pcib_softc *sc, uint16_t val, uint16_t mask)
{
	device_t dev;
	uint16_t ctl, new;

	dev = sc->dev;

	if (sc->flags & PCIB_HOTPLUG_CMD_PENDING)
		return;

	ctl = pcie_read_config(dev, PCIER_SLOT_CTL, 2);
	new = (ctl & ~mask) | val;
	if (new == ctl)
		return;
	if (bootverbose)
		device_printf(dev, "HotPlug command: %04x -> %04x\n", ctl, new);
	pcie_write_config(dev, PCIER_SLOT_CTL, new, 2);
	if (!(sc->pcie_slot_cap & PCIEM_SLOT_CAP_NCCS) &&
	    (ctl & new) & PCIEM_SLOT_CTL_CCIE) {
		sc->flags |= PCIB_HOTPLUG_CMD_PENDING;
		if (!cold)
			callout_reset(&sc->pcie_cc_timer, hz,
			    pcib_pcie_cc_timeout, sc);
	}
}

static void
pcib_pcie_hotplug_command_completed(struct pcib_softc *sc)
{
	device_t dev;

	dev = sc->dev;

	if (bootverbose)
		device_printf(dev, "Command Completed\n");
	if (!(sc->flags & PCIB_HOTPLUG_CMD_PENDING))
		return;
	callout_stop(&sc->pcie_cc_timer);
	sc->flags &= ~PCIB_HOTPLUG_CMD_PENDING;
	wakeup(sc);
}

/*
 * Returns true if a card is fully inserted from the user's
 * perspective.  It may not yet be ready for access, but the driver
 * can now start enabling access if necessary.
 */
static bool
pcib_hotplug_inserted(struct pcib_softc *sc)
{

	/* Pretend the card isn't present if a detach is forced. */
	if (sc->flags & PCIB_DETACHING)
		return (false);

	/* Card must be present in the slot. */
	if ((sc->pcie_slot_sta & PCIEM_SLOT_STA_PDS) == 0)
		return (false);

	/* A power fault implicitly turns off power to the slot. */
	if (sc->pcie_slot_sta & PCIEM_SLOT_STA_PFD)
		return (false);

	/* If the MRL is disengaged, the slot is powered off. */
	if (sc->pcie_slot_cap & PCIEM_SLOT_CAP_MRLSP &&
	    (sc->pcie_slot_sta & PCIEM_SLOT_STA_MRLSS) != 0)
		return (false);

	return (true);
}

/*
 * Returns -1 if the card is fully inserted, powered, and ready for
 * access.  Otherwise, returns 0.
 */
static int
pcib_hotplug_present(struct pcib_softc *sc)
{

	/* Card must be inserted. */
	if (!pcib_hotplug_inserted(sc))
		return (0);

	/*
	 * Require the Electromechanical Interlock to be engaged if
	 * present.
	 */
	if (sc->pcie_slot_cap & PCIEM_SLOT_CAP_EIP &&
	    (sc->pcie_slot_sta & PCIEM_SLOT_STA_EIS) == 0)
		return (0);

	/* Require the Data Link Layer to be active. */
	if (!(sc->pcie_link_sta & PCIEM_LINK_STA_DL_ACTIVE))
		return (0);

	return (-1);
}

static void
pcib_pcie_hotplug_update(struct pcib_softc *sc, uint16_t val, uint16_t mask,
    bool schedule_task)
{
	bool card_inserted, ei_engaged;

	/* Clear DETACHING if Presence Detect has cleared. */
	if ((sc->pcie_slot_sta & (PCIEM_SLOT_STA_PDC | PCIEM_SLOT_STA_PDS)) ==
	    PCIEM_SLOT_STA_PDC)
		sc->flags &= ~PCIB_DETACHING;

	card_inserted = pcib_hotplug_inserted(sc);

	/* Turn the power indicator on if a card is inserted. */
	if (sc->pcie_slot_cap & PCIEM_SLOT_CAP_PIP) {
		mask |= PCIEM_SLOT_CTL_PIC;
		if (card_inserted)
			val |= PCIEM_SLOT_CTL_PI_ON;
		else if (sc->flags & PCIB_DETACH_PENDING)
			val |= PCIEM_SLOT_CTL_PI_BLINK;
		else
			val |= PCIEM_SLOT_CTL_PI_OFF;
	}

	/* Turn the power on via the Power Controller if a card is inserted. */
	if (sc->pcie_slot_cap & PCIEM_SLOT_CAP_PCP) {
		mask |= PCIEM_SLOT_CTL_PCC;
		if (card_inserted)
			val |= PCIEM_SLOT_CTL_PC_ON;
		else
			val |= PCIEM_SLOT_CTL_PC_OFF;
	}

	/*
	 * If a card is inserted, enable the Electromechanical
	 * Interlock.  If a card is not inserted (or we are in the
	 * process of detaching), disable the Electromechanical
	 * Interlock.
	 */
	if (sc->pcie_slot_cap & PCIEM_SLOT_CAP_EIP) {
		mask |= PCIEM_SLOT_CTL_EIC;
		ei_engaged = (sc->pcie_slot_sta & PCIEM_SLOT_STA_EIS) != 0;
		if (card_inserted != ei_engaged)
			val |= PCIEM_SLOT_CTL_EIC;
	}

	/*
	 * Start a timer to see if the Data Link Layer times out.
	 * Note that we only start the timer if Presence Detect or MRL Sensor
	 * changed on this interrupt.  Stop any scheduled timer if
	 * the Data Link Layer is active.
	 */
	if (card_inserted &&
	    !(sc->pcie_link_sta & PCIEM_LINK_STA_DL_ACTIVE) &&
	    sc->pcie_slot_sta &
	    (PCIEM_SLOT_STA_MRLSC | PCIEM_SLOT_STA_PDC)) {
		if (cold)
			device_printf(sc->dev,
			    "Data Link Layer inactive\n");
		else
			callout_reset(&sc->pcie_dll_timer, hz,
			    pcib_pcie_dll_timeout, sc);
	} else if (sc->pcie_link_sta & PCIEM_LINK_STA_DL_ACTIVE)
		callout_stop(&sc->pcie_dll_timer);

	pcib_pcie_hotplug_command(sc, val, mask);

	/*
	 * During attach the child "pci" device is added synchronously;
	 * otherwise, the task is scheduled to manage the child
	 * device.
	 */
	if (schedule_task &&
	    (pcib_hotplug_present(sc) != 0) != (sc->child != NULL))
		taskqueue_enqueue(taskqueue_thread, &sc->pcie_hp_task);
}

static void
pcib_pcie_intr_hotplug(void *arg)
{
	struct pcib_softc *sc;
	device_t dev;

	sc = arg;
	dev = sc->dev;
	sc->pcie_slot_sta = pcie_read_config(dev, PCIER_SLOT_STA, 2);

	/* Clear the events just reported. */
	pcie_write_config(dev, PCIER_SLOT_STA, sc->pcie_slot_sta, 2);

	if (bootverbose)
		device_printf(dev, "HotPlug interrupt: %#x\n",
		    sc->pcie_slot_sta);

	if (sc->pcie_slot_sta & PCIEM_SLOT_STA_ABP) {
		if (sc->flags & PCIB_DETACH_PENDING) {
			device_printf(dev,
			    "Attention Button Pressed: Detach Cancelled\n");
			sc->flags &= ~PCIB_DETACH_PENDING;
			callout_stop(&sc->pcie_ab_timer);
		} else {
			device_printf(dev,
		    "Attention Button Pressed: Detaching in 5 seconds\n");
			sc->flags |= PCIB_DETACH_PENDING;
			callout_reset(&sc->pcie_ab_timer, 5 * hz,
			    pcib_pcie_ab_timeout, sc);
		}
	}
	if (sc->pcie_slot_sta & PCIEM_SLOT_STA_PFD)
		device_printf(dev, "Power Fault Detected\n");
	if (sc->pcie_slot_sta & PCIEM_SLOT_STA_MRLSC)
		device_printf(dev, "MRL Sensor Changed to %s\n",
		    sc->pcie_slot_sta & PCIEM_SLOT_STA_MRLSS ? "open" :
		    "closed");
	if (bootverbose && sc->pcie_slot_sta & PCIEM_SLOT_STA_PDC)
		device_printf(dev, "Presence Detect Changed to %s\n",
		    sc->pcie_slot_sta & PCIEM_SLOT_STA_PDS ? "card present" :
		    "empty");
	if (sc->pcie_slot_sta & PCIEM_SLOT_STA_CC)
		pcib_pcie_hotplug_command_completed(sc);
	if (sc->pcie_slot_sta & PCIEM_SLOT_STA_DLLSC) {
		sc->pcie_link_sta = pcie_read_config(dev, PCIER_LINK_STA, 2);
		if (bootverbose)
			device_printf(dev,
			    "Data Link Layer State Changed to %s\n",
			    sc->pcie_link_sta & PCIEM_LINK_STA_DL_ACTIVE ?
			    "active" : "inactive");
	}

	pcib_pcie_hotplug_update(sc, 0, 0, true);
}

static void
pcib_pcie_hotplug_task(void *context, int pending)
{
	struct pcib_softc *sc;
	device_t dev;

	sc = context;
	mtx_lock(&Giant);
	dev = sc->dev;
	if (pcib_hotplug_present(sc) != 0) {
		if (sc->child == NULL) {
			sc->child = device_add_child(dev, "pci", -1);
			bus_generic_attach(dev);
		}
	} else {
		if (sc->child != NULL) {
			if (device_delete_child(dev, sc->child) == 0)
				sc->child = NULL;
		}
	}
	mtx_unlock(&Giant);
}

static void
pcib_pcie_ab_timeout(void *arg)
{
	struct pcib_softc *sc;

	sc = arg;
	mtx_assert(&Giant, MA_OWNED);
	if (sc->flags & PCIB_DETACH_PENDING) {
		sc->flags |= PCIB_DETACHING;
		sc->flags &= ~PCIB_DETACH_PENDING;
		pcib_pcie_hotplug_update(sc, 0, 0, true);
	}
}

static void
pcib_pcie_cc_timeout(void *arg)
{
	struct pcib_softc *sc;
	device_t dev;
	uint16_t sta;

	sc = arg;
	dev = sc->dev;
	mtx_assert(&Giant, MA_OWNED);
	sta = pcie_read_config(dev, PCIER_SLOT_STA, 2);
	if (!(sta & PCIEM_SLOT_STA_CC)) {
		device_printf(dev,
		    "HotPlug Command Timed Out - forcing detach\n");
		sc->flags &= ~(PCIB_HOTPLUG_CMD_PENDING | PCIB_DETACH_PENDING);
		sc->flags |= PCIB_DETACHING;
		pcib_pcie_hotplug_update(sc, 0, 0, true);
	} else {
		device_printf(dev,
	    "Missed HotPlug interrupt waiting for Command Completion\n");
		pcib_pcie_intr_hotplug(sc);
	}
}

static void
pcib_pcie_dll_timeout(void *arg)
{
	struct pcib_softc *sc;
	device_t dev;
	uint16_t sta;

	sc = arg;
	dev = sc->dev;
	mtx_assert(&Giant, MA_OWNED);
	sta = pcie_read_config(dev, PCIER_LINK_STA, 2);
	if (!(sta & PCIEM_LINK_STA_DL_ACTIVE)) {
		device_printf(dev,
		    "Timed out waiting for Data Link Layer Active\n");
		sc->flags |= PCIB_DETACHING;
		pcib_pcie_hotplug_update(sc, 0, 0, true);
	} else if (sta != sc->pcie_link_sta) {
		device_printf(dev,
		    "Missed HotPlug interrupt waiting for DLL Active\n");
		pcib_pcie_intr_hotplug(sc);
	}
}

static int
pcib_alloc_pcie_irq(struct pcib_softc *sc)
{
	device_t dev;
	int count, error, rid;

	rid = -1;
	dev = sc->dev;

	/*
	 * For simplicity, only use MSI-X if there is a single message.
	 * To support a device with multiple messages we would have to
	 * use remap intr if the MSI number is not 0.
	 */
	count = pci_msix_count(dev);
	if (count == 1) {
		error = pci_alloc_msix(dev, &count);
		if (error == 0)
			rid = 1;
	}

	if (rid < 0 && pci_msi_count(dev) > 0) {
		count = 1;
		error = pci_alloc_msi(dev, &count);
		if (error == 0)
			rid = 1;
	}

	if (rid < 0)
		rid = 0;

	sc->pcie_irq = bus_alloc_resource_any(dev, SYS_RES_IRQ, &rid,
	    RF_ACTIVE);
	if (sc->pcie_irq == NULL) {
		device_printf(dev,
		    "Failed to allocate interrupt for PCI-e events\n");
		if (rid > 0)
			pci_release_msi(dev);
		return (ENXIO);
	}

	error = bus_setup_intr(dev, sc->pcie_irq, INTR_TYPE_MISC,
	    NULL, pcib_pcie_intr_hotplug, sc, &sc->pcie_ihand);
	if (error) {
		device_printf(dev, "Failed to setup PCI-e interrupt handler\n");
		bus_release_resource(dev, SYS_RES_IRQ, rid, sc->pcie_irq);
		if (rid > 0)
			pci_release_msi(dev);
		return (error);
	}
	return (0);
}

static int
pcib_release_pcie_irq(struct pcib_softc *sc)
{
	device_t dev;
	int error;

	dev = sc->dev;
	error = bus_teardown_intr(dev, sc->pcie_irq, sc->pcie_ihand);
	if (error)
		return (error);
	error = bus_free_resource(dev, SYS_RES_IRQ, sc->pcie_irq);
	if (error)
		return (error);
	return (pci_release_msi(dev));
}

static void
pcib_setup_hotplug(struct pcib_softc *sc)
{
	device_t dev;
	uint16_t mask, val;

	dev = sc->dev;
	callout_init(&sc->pcie_ab_timer, 0);
	callout_init(&sc->pcie_cc_timer, 0);
	callout_init(&sc->pcie_dll_timer, 0);
	TASK_INIT(&sc->pcie_hp_task, 0, pcib_pcie_hotplug_task, sc);

	/* Allocate IRQ. */
	if (pcib_alloc_pcie_irq(sc) != 0)
		return;

	sc->pcie_link_sta = pcie_read_config(dev, PCIER_LINK_STA, 2);
	sc->pcie_slot_sta = pcie_read_config(dev, PCIER_SLOT_STA, 2);

	/* Clear any events previously pending. */
	pcie_write_config(dev, PCIER_SLOT_STA, sc->pcie_slot_sta, 2);

	/* Enable HotPlug events. */
	mask = PCIEM_SLOT_CTL_DLLSCE | PCIEM_SLOT_CTL_HPIE |
	    PCIEM_SLOT_CTL_CCIE | PCIEM_SLOT_CTL_PDCE | PCIEM_SLOT_CTL_MRLSCE |
	    PCIEM_SLOT_CTL_PFDE | PCIEM_SLOT_CTL_ABPE;
	val = PCIEM_SLOT_CTL_DLLSCE | PCIEM_SLOT_CTL_HPIE | PCIEM_SLOT_CTL_PDCE;
	if (sc->pcie_slot_cap & PCIEM_SLOT_CAP_APB)
		val |= PCIEM_SLOT_CTL_ABPE;
	if (sc->pcie_slot_cap & PCIEM_SLOT_CAP_PCP)
		val |= PCIEM_SLOT_CTL_PFDE;
	if (sc->pcie_slot_cap & PCIEM_SLOT_CAP_MRLSP)
		val |= PCIEM_SLOT_CTL_MRLSCE;
	if (!(sc->pcie_slot_cap & PCIEM_SLOT_CAP_NCCS))
		val |= PCIEM_SLOT_CTL_CCIE;

	/* Turn the attention indicator off. */
	if (sc->pcie_slot_cap & PCIEM_SLOT_CAP_AIP) {
		mask |= PCIEM_SLOT_CTL_AIC;
		val |= PCIEM_SLOT_CTL_AI_OFF;
	}

	pcib_pcie_hotplug_update(sc, val, mask, false);
}

static int
pcib_detach_hotplug(struct pcib_softc *sc)
{
	uint16_t mask, val;
	int error;

	/* Disable the card in the slot and force it to detach. */
	if (sc->flags & PCIB_DETACH_PENDING) {
		sc->flags &= ~PCIB_DETACH_PENDING;
		callout_stop(&sc->pcie_ab_timer);
	}
	sc->flags |= PCIB_DETACHING;

	if (sc->flags & PCIB_HOTPLUG_CMD_PENDING) {
		callout_stop(&sc->pcie_cc_timer);
		tsleep(sc, 0, "hpcmd", hz);
		sc->flags &= ~PCIB_HOTPLUG_CMD_PENDING;
	}

	/* Disable HotPlug events. */
	mask = PCIEM_SLOT_CTL_DLLSCE | PCIEM_SLOT_CTL_HPIE |
	    PCIEM_SLOT_CTL_CCIE | PCIEM_SLOT_CTL_PDCE | PCIEM_SLOT_CTL_MRLSCE |
	    PCIEM_SLOT_CTL_PFDE | PCIEM_SLOT_CTL_ABPE;
	val = 0;

	/* Turn the attention indicator off. */
	if (sc->pcie_slot_cap & PCIEM_SLOT_CAP_AIP) {
		mask |= PCIEM_SLOT_CTL_AIC;
		val |= PCIEM_SLOT_CTL_AI_OFF;
	}

	pcib_pcie_hotplug_update(sc, val, mask, false);

	error = pcib_release_pcie_irq(sc);
	if (error)
		return (error);
	taskqueue_drain(taskqueue_thread, &sc->pcie_hp_task);
	callout_drain(&sc->pcie_ab_timer);
	callout_drain(&sc->pcie_cc_timer);
	callout_drain(&sc->pcie_dll_timer);
	return (0);
}
#endif

/*
 * Get current bridge configuration.
 */
static void
pcib_cfg_save(struct pcib_softc *sc)
{
#ifndef NEW_PCIB
	device_t	dev;
	uint16_t command;

	dev = sc->dev;

	command = pci_read_config(dev, PCIR_COMMAND, 2);
	if (command & PCIM_CMD_PORTEN)
		pcib_get_io_decode(sc);
	if (command & PCIM_CMD_MEMEN)
		pcib_get_mem_decode(sc);
#endif
}

/*
 * Restore previous bridge configuration.
 */
static void
pcib_cfg_restore(struct pcib_softc *sc)
{
#ifndef NEW_PCIB
	uint16_t command;
#endif

#ifdef NEW_PCIB
	pcib_write_windows(sc, WIN_IO | WIN_MEM | WIN_PMEM);
#else
	command = pci_read_config(sc->dev, PCIR_COMMAND, 2);
	if (command & PCIM_CMD_PORTEN)
		pcib_set_io_decode(sc);
	if (command & PCIM_CMD_MEMEN)
		pcib_set_mem_decode(sc);
#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;
    struct sysctl_ctx_list *sctx;
    struct sysctl_oid	*soid;
    int comma;

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

    /*
     * Get current bridge configuration.
     */
    sc->domain = pci_get_domain(dev);
#if !(defined(NEW_PCIB) && defined(PCI_RES_BUS))
    sc->bus.sec = pci_read_config(dev, PCIR_SECBUS_1, 1);
    sc->bus.sub = pci_read_config(dev, PCIR_SUBBUS_1, 1);
#endif
    sc->bridgectl = pci_read_config(dev, PCIR_BRIDGECTL_1, 2);
    pcib_cfg_save(sc);

    /*
     * The primary bus register should always be the bus of the
     * parent.
     */
    sc->pribus = pci_get_bus(dev);
    pci_write_config(dev, PCIR_PRIBUS_1, sc->pribus, 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->bus.sec, 0, "Secondary bus number");
    SYSCTL_ADD_UINT(sctx, SYSCTL_CHILDREN(soid), OID_AUTO, "subbus",
      CTLFLAG_RD, &sc->bus.sub, 0, "Subordinate bus number");

    /*
     * Quirk handling.
     */
    switch (pci_get_devid(dev)) {
#if !(defined(NEW_PCIB) && defined(PCI_RES_BUS))
    case 0x12258086:		/* Intel 82454KX/GX (Orion) */
	{
	    uint8_t	supbus;

	    supbus = pci_read_config(dev, 0x41, 1);
	    if (supbus != 0xff) {
		sc->bus.sec = supbus + 1;
		sc->bus.sub = supbus + 1;
	    }
	    break;
	}
#endif

    /*
     * 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 are also Toshiba and Cavium ThunderX bridges
     * that behave this way.
     */
    case 0xa002177d:		/* Cavium ThunderX */
    case 0x124b8086:		/* Intel 82380FB Mobile */
    case 0x060513d7:		/* Toshiba ???? */
	sc->flags |= PCIB_SUBTRACTIVE;
	break;

#if !(defined(NEW_PCIB) && defined(PCI_RES_BUS))
    /* Compaq R3000 BIOS sets wrong subordinate bus number. */
    case 0x00dd10de:
	{
	    char *cp;

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

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

    if (pci_msix_device_blacklisted(dev))
	sc->flags |= PCIB_DISABLE_MSIX;

    /*
     * 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 PCI_HP
    pcib_probe_hotplug(sc);
#endif
#ifdef NEW_PCIB
#ifdef PCI_RES_BUS
    pcib_setup_secbus(dev, &sc->bus, 1);
#endif
    pcib_probe_windows(sc);
#endif
#ifdef PCI_HP
    if (sc->flags & PCIB_HOTPLUG)
	    pcib_setup_hotplug(sc);
#endif
    if (bootverbose) {
	device_printf(dev, "  domain            %d\n", sc->domain);
	device_printf(dev, "  secondary bus     %d\n", sc->bus.sec);
	device_printf(dev, "  subordinate bus   %d\n", sc->bus.sub);
#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
	if (sc->bridgectl & (PCIB_BCR_ISA_ENABLE | PCIB_BCR_VGA_ENABLE) ||
	    sc->flags & PCIB_SUBTRACTIVE) {
		device_printf(dev, "  special decode    ");
		comma = 0;
		if (sc->bridgectl & PCIB_BCR_ISA_ENABLE) {
			printf("ISA");
			comma = 1;
		}
		if (sc->bridgectl & PCIB_BCR_VGA_ENABLE) {
			printf("%sVGA", comma ? ", " : "");
			comma = 1;
		}
		if (sc->flags & PCIB_SUBTRACTIVE)
			printf("%ssubtractive", comma ? ", " : "");
		printf("\n");
	}
    }

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

#ifdef PCI_HP
static int
pcib_present(struct pcib_softc *sc)
{

	if (sc->flags & PCIB_HOTPLUG)
		return (pcib_hotplug_present(sc) != 0);
	return (1);
}
#endif

int
pcib_attach_child(device_t dev)
{
	struct pcib_softc *sc;

	sc = device_get_softc(dev);
	if (sc->bus.sec == 0) {
		/* no secondary bus; we should have fixed this */
		return(0);
	}

#ifdef PCI_HP
	if (!pcib_present(sc)) {
		/* An empty HotPlug slot, so don't add a PCI bus yet. */
		return (0);
	}
#endif

	sc->child = device_add_child(dev, "pci", -1);
	return (bus_generic_attach(dev));
}

int
pcib_attach(device_t dev)
{

    pcib_attach_common(dev);
    return (pcib_attach_child(dev));
}

int
pcib_detach(device_t dev)
{
#if defined(PCI_HP) || defined(NEW_PCIB)
	struct pcib_softc *sc;
#endif
	int error;

#if defined(PCI_HP) || defined(NEW_PCIB)
	sc = device_get_softc(dev);
#endif
	error = bus_generic_detach(dev);
	if (error)
		return (error);
#ifdef PCI_HP
	if (sc->flags & PCIB_HOTPLUG) {
		error = pcib_detach_hotplug(sc);
		if (error)
			return (error);
	}
#endif
	error = device_delete_children(dev);
	if (error)
		return (error);
#ifdef NEW_PCIB
	pcib_free_windows(sc);
#ifdef PCI_RES_BUS
	pcib_free_secbus(dev, &sc->bus);
#endif
#endif
	return (0);
}

int
pcib_suspend(device_t dev)
{

	pcib_cfg_save(device_get_softc(dev));
	return (bus_generic_suspend(dev));
}

int
pcib_resume(device_t dev)
{

	pcib_cfg_restore(device_get_softc(dev));
	return (bus_generic_resume(dev));
}

void
pcib_bridge_init(device_t dev)
{
	pci_write_config(dev, PCIR_IOBASEL_1, 0xff, 1);
	pci_write_config(dev, PCIR_IOBASEH_1, 0xffff, 2);
	pci_write_config(dev, PCIR_IOLIMITL_1, 0, 1);
	pci_write_config(dev, PCIR_IOLIMITH_1, 0, 2);
	pci_write_config(dev, PCIR_MEMBASE_1, 0xffff, 2);
	pci_write_config(dev, PCIR_MEMLIMIT_1, 0, 2);
	pci_write_config(dev, PCIR_PMBASEL_1, 0xffff, 2);
	pci_write_config(dev, PCIR_PMBASEH_1, 0xffffffff, 4);
	pci_write_config(dev, PCIR_PMLIMITL_1, 0, 2);
	pci_write_config(dev, PCIR_PMLIMITH_1, 0, 4);
}

int
pcib_child_present(device_t dev, device_t child)
{
#ifdef PCI_HP
	struct pcib_softc *sc = device_get_softc(dev);
	int retval;

	retval = bus_child_present(dev);
	if (retval != 0 && sc->flags & PCIB_HOTPLUG)
		retval = pcib_hotplug_present(sc);
	return (retval);
#else
	return (bus_child_present(dev));
#endif
}

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->bus.sec;
	return(0);
    }
    return(ENOENT);
}

int
pcib_write_ivar(device_t dev, device_t child, int which, uintptr_t value)
{

    switch (which) {
    case PCIB_IVAR_DOMAIN:
	return(EINVAL);
    case PCIB_IVAR_BUS:
	return(EINVAL);
    }
    return(ENOENT);
}

#ifdef NEW_PCIB
/*
 * 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, rman_res_t start, rman_res_t end,
    rman_res_t 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 (%#jx-%#jx) 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);
}

/* Allocate a fresh resource range for an unconfigured window. */
static int
pcib_alloc_new_window(struct pcib_softc *sc, struct pcib_window *w, int type,
    rman_res_t start, rman_res_t end, rman_res_t count, u_int flags)
{
	struct resource *res;
	rman_res_t base, limit, wmask;
	int rid;

	/*
	 * If this is an I/O window on a bridge with ISA enable set
	 * and the start address is below 64k, then try to allocate an
	 * initial window of 0x1000 bytes long starting at address
	 * 0xf000 and walking down.  Note that if the original request
	 * was larger than the non-aliased range size of 0x100 our
	 * caller would have raised the start address up to 64k
	 * already.
	 */
	if (type == SYS_RES_IOPORT && sc->bridgectl & PCIB_BCR_ISA_ENABLE &&
	    start < 65536) {
		for (base = 0xf000; (long)base >= 0; base -= 0x1000) {
			limit = base + 0xfff;

			/*
			 * Skip ranges that wouldn't work for the
			 * original request.  Note that the actual
			 * window that overlaps are the non-alias
			 * ranges within [base, limit], so this isn't
			 * quite a simple comparison.
			 */
			if (start + count > limit - 0x400)
				continue;
			if (base == 0) {
				/*
				 * The first open region for the window at
				 * 0 is 0x400-0x4ff.
				 */
				if (end - count + 1 < 0x400)
					continue;
			} else {
				if (end - count + 1 < base)
					continue;
			}

			if (pcib_alloc_nonisa_ranges(sc, base, limit) == 0) {
				w->base = base;
				w->limit = limit;
				return (0);
			}
		}
		return (ENOSPC);
	}

	wmask = ((rman_res_t)1 << w->step) - 1;
	if (RF_ALIGNMENT(flags) < w->step) {
		flags &= ~RF_ALIGNMENT_MASK;
		flags |= RF_ALIGNMENT_LOG2(w->step);
	}
	start &= ~wmask;
	end |= wmask;
	count = roundup2(count, (rman_res_t)1 << w->step);
	rid = w->reg;
	res = bus_alloc_resource(sc->dev, type, &rid, start, end, count,
	    flags & ~RF_ACTIVE);
	if (res == NULL)
		return (ENOSPC);
	pcib_add_window_resources(w, &res, 1);
	pcib_activate_window(sc, type);
	w->base = rman_get_start(res);
	w->limit = rman_get_end(res);
	return (0);
}

/* Try to expand an existing window to the requested base and limit. */
static int
pcib_expand_window(struct pcib_softc *sc, struct pcib_window *w, int type,
    rman_res_t base, rman_res_t limit)
{
	struct resource *res;
	int error, i, force_64k_base;

	KASSERT(base <= w->base && limit >= w->limit,
	    ("attempting to shrink window"));

	/*
	 * XXX: pcib_grow_window() doesn't try to do this anyway and
	 * the error handling for all the edge cases would be tedious.
	 */
	KASSERT(limit == w->limit || base == w->base,
	    ("attempting to grow both ends of a window"));

	/*
	 * Yet more special handling for requests to expand an I/O
	 * window behind an ISA-enabled bridge.  Since I/O windows
	 * have to grow in 0x1000 increments and the end of the 0xffff
	 * range is an alias, growing a window below 64k will always
	 * result in allocating new resources and never adjusting an
	 * existing resource.
	 */
	if (type == SYS_RES_IOPORT && sc->bridgectl & PCIB_BCR_ISA_ENABLE &&
	    (limit <= 65535 || (base <= 65535 && base != w->base))) {
		KASSERT(limit == w->limit || limit <= 65535,
		    ("attempting to grow both ends across 64k ISA alias"));

		if (base != w->base)
			error = pcib_alloc_nonisa_ranges(sc, base, w->base - 1);
		else
			error = pcib_alloc_nonisa_ranges(sc, w->limit + 1,
			    limit);
		if (error == 0) {
			w->base = base;
			w->limit = limit;
		}
		return (error);
	}

	/*
	 * Find the existing resource to adjust.  Usually there is only one,
	 * but for an ISA-enabled bridge we might be growing the I/O window
	 * above 64k and need to find the existing resource that maps all
	 * of the area above 64k.
	 */
	for (i = 0; i < w->count; i++) {
		if (rman_get_end(w->res[i]) == w->limit)
			break;
	}
	KASSERT(i != w->count, ("did not find existing resource"));
	res = w->res[i];

	/*
	 * Usually the resource we found should match the window's
	 * existing range.  The one exception is the ISA-enabled case
	 * mentioned above in which case the resource should start at
	 * 64k.
	 */
	if (type == SYS_RES_IOPORT && sc->bridgectl & PCIB_BCR_ISA_ENABLE &&
	    w->base <= 65535) {
		KASSERT(rman_get_start(res) == 65536,
		    ("existing resource mismatch"));
		force_64k_base = 1;
	} else {
		KASSERT(w->base == rman_get_start(res),
		    ("existing resource mismatch"));
		force_64k_base = 0;
	}

	error = bus_adjust_resource(sc->dev, type, res, force_64k_base ?
	    rman_get_start(res) : base, limit);
	if (error)
		return (error);

	/* Add the newly allocated region to the resource manager. */
	if (w->base != base) {
		error = rman_manage_region(&w->rman, base, w->base - 1);
		w->base = base;
	} else {
		error = rman_manage_region(&w->rman, w->limit + 1, limit);
		w->limit = limit;
	}
	if (error) {
		if (bootverbose)
			device_printf(sc->dev,
			    "failed to expand %s resource manager\n", w->name);
		(void)bus_adjust_resource(sc->dev, type, res, force_64k_base ?
		    rman_get_start(res) : w->base, w->limit);
	}
	return (error);
}

/*
 * Attempt to grow a window to make room for a given resource request.
 */
static int
pcib_grow_window(struct pcib_softc *sc, struct pcib_window *w, int type,
    rman_res_t start, rman_res_t end, rman_res_t count, u_int flags)
{
	rman_res_t align, start_free, end_free, front, back, wmask;
	int error;

	/*
	 * Clamp the desired resource range to the maximum address
	 * this window supports.  Reject impossible requests.
	 *
	 * For I/O port requests behind a bridge with the ISA enable
	 * bit set, force large allocations to start above 64k.
	 */
	if (!w->valid)
		return (EINVAL);
	if (sc->bridgectl & PCIB_BCR_ISA_ENABLE && count > 0x100 &&
	    start < 65536)
		start = 65536;
	if (end > w->rman.rm_end)
		end = w->rman.rm_end;
	if (start + count - 1 > end || start + count < start)
		return (EINVAL);
	wmask = ((rman_res_t)1 << w->step) - 1;

	/*
	 * If there is no resource at all, just try to allocate enough
	 * aligned space for this resource.
	 */
	if (w->res == NULL) {
		error = pcib_alloc_new_window(sc, w, type, start, end, count,
		    flags);
		if (error) {
			if (bootverbose)
				device_printf(sc->dev,
		    "failed to allocate initial %s window (%#jx-%#jx,%#jx)\n",
				    w->name, start, end, count);
			return (error);
		}
		if (bootverbose)
			device_printf(sc->dev,
			    "allocated initial %s window of %#jx-%#jx\n",
			    w->name, (uintmax_t)w->base, (uintmax_t)w->limit);
		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.
	 *
	 * Growing an I/O window below 64k for a bridge with the ISA
	 * enable bit doesn't require any special magic as the step
	 * size of an I/O window (1k) always includes multiple
	 * non-alias ranges when it is grown in either direction.
	 *
	 * 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 (%#jx-%#jx,%#jx)\n",
		    w->name, start, end, count);
	align = (rman_res_t)1 << RF_ALIGNMENT(flags);
	if (start < w->base) {
		if (rman_first_free_region(&w->rman, &start_free, &end_free) !=
		    0 || start_free != w->base)
			end_free = w->base;
		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: %#jx-%#jx\n",
				    front, end_free);
			front &= ~wmask;
			front = w->base - front;
		} else
			front = 0;
	} else
		front = 0;
	if (end > w->limit) {
		if (rman_last_free_region(&w->rman, &start_free, &end_free) !=
		    0 || end_free != w->limit)
			start_free = w->limit + 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: %#jx-%#jx\n",
				    start_free, back);
			back |= wmask;
			back -= w->limit;
		} 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 = pcib_expand_window(sc, w, type, w->base - front,
			    w->limit);
			if (error == 0)
				break;
			front = 0;
		} else {
			error = pcib_expand_window(sc, w, type, w->base,
			    w->limit + back);
			if (error == 0)
				break;
			back = 0;
		}
	}

	if (error)
		return (error);
	if (bootverbose)
		device_printf(sc->dev, "grew %s window to %#jx-%#jx\n",
		    w->name, (uintmax_t)w->base, (uintmax_t)w->limit);

updatewin:
	/* Write the new window. */
	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,
    rman_res_t start, rman_res_t end, rman_res_t 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) {
#ifdef PCI_RES_BUS
	case PCI_RES_BUS:
		return (pcib_alloc_subbus(&sc->bus, child, rid, start, end,
		    count, flags));
#endif
	case SYS_RES_IOPORT:
		if (pcib_is_isa_range(sc, start, end, count))
			return (NULL);
		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,
    rman_res_t start, rman_res_t 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,
    rman_res_t start, rman_res_t end, rman_res_t 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 (%jx) < start (%jx)\n",
			    end, start);
			start = 0;
			end = 0;
			ok = 0;
		}
		if (!ok) {
			device_printf(dev, "%s%srequested unsupported I/O "
			    "range 0x%jx-0x%jx (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%jx-0x%jx: 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 (%jx) < start (%jx)\n",
			    end, start);
			start = 0;
			end = 0;
			ok = 0;
		}
		if (!ok && bootverbose)
			device_printf(dev,
			    "%s%srequested unsupported memory range %#jx-%#jx "
			    "(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%jx-0x%jx: 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

/*
 * If ARI is enabled on this downstream port, translate the function number
 * to the non-ARI slot/function.  The downstream port will convert it back in
 * hardware.  If ARI is not enabled slot and func are not modified.
 */
static __inline void
pcib_xlate_ari(device_t pcib, int bus, int *slot, int *func)
{
	struct pcib_softc *sc;
	int ari_func;

	sc = device_get_softc(pcib);
	ari_func = *func;

	if (sc->flags & PCIB_ENABLE_ARI) {
		KASSERT(*slot == 0,
		    ("Non-zero slot number with ARI enabled!"));
		*slot = PCIE_ARI_SLOT(ari_func);
		*func = PCIE_ARI_FUNC(ari_func);
	}
}


static void
pcib_enable_ari(struct pcib_softc *sc, uint32_t pcie_pos)
{
	uint32_t ctl2;

	ctl2 = pci_read_config(sc->dev, pcie_pos + PCIER_DEVICE_CTL2, 4);
	ctl2 |= PCIEM_CTL2_ARI;
	pci_write_config(sc->dev, pcie_pos + PCIER_DEVICE_CTL2, ctl2, 4);

	sc->flags |= PCIB_ENABLE_ARI;
}

/*
 * PCIB interface.
 */
int
pcib_maxslots(device_t dev)
{
	uint32_t pcie_pos;
	uint16_t val;

	/*
	 * If this is a PCIe rootport or downstream switch port, there's only
	 * one slot permitted.
	 */
	if (pci_find_cap(dev, PCIY_EXPRESS, &pcie_pos) == 0) {
		val = pci_read_config(dev, pcie_pos + PCIER_FLAGS, 2);
		val &= PCIEM_FLAGS_TYPE;
		if (val == PCIEM_TYPE_ROOT_PORT ||
		    val == PCIEM_TYPE_DOWNSTREAM_PORT)
			return (0);
	}
	return (PCI_SLOTMAX);
}

static int
pcib_ari_maxslots(device_t dev)
{
	struct pcib_softc *sc;

	sc = device_get_softc(dev);

	if (sc->flags & PCIB_ENABLE_ARI)
		return (PCIE_ARI_SLOTMAX);
	else
		return (pcib_maxslots(dev));
}

static int
pcib_ari_maxfuncs(device_t dev)
{
	struct pcib_softc *sc;

	sc = device_get_softc(dev);

	if (sc->flags & PCIB_ENABLE_ARI)
		return (PCIE_ARI_FUNCMAX);
	else
		return (PCI_FUNCMAX);
}

static void
pcib_ari_decode_rid(device_t pcib, uint16_t rid, int *bus, int *slot,
    int *func)
{
	struct pcib_softc *sc;

	sc = device_get_softc(pcib);

	*bus = PCI_RID2BUS(rid);
	if (sc->flags & PCIB_ENABLE_ARI) {
		*slot = PCIE_ARI_RID2SLOT(rid);
		*func = PCIE_ARI_RID2FUNC(rid);
	} else {
		*slot = PCI_RID2SLOT(rid);
		*func = PCI_RID2FUNC(rid);
	}
}

/*
 * Since we are a child of a PCI bus, its parent must support the pcib interface.
 */
static uint32_t
pcib_read_config(device_t dev, u_int b, u_int s, u_int f, u_int reg, int width)
{
#ifdef PCI_HP
	struct pcib_softc *sc;

	sc = device_get_softc(dev);
	if (!pcib_present(sc)) {
		switch (width) {
		case 2:
			return (0xffff);
		case 1:
			return (0xff);
		default:
			return (0xffffffff);
		}
	}
#endif
	pcib_xlate_ari(dev, b, &s, &f);
	return(PCIB_READ_CONFIG(device_get_parent(device_get_parent(dev)), b, s,
	    f, reg, width));
}

static void
pcib_write_config(device_t dev, u_int b, u_int s, u_int f, u_int reg, uint32_t val, int width)
{
#ifdef PCI_HP
	struct pcib_softc *sc;

	sc = device_get_softc(dev);
	if (!pcib_present(sc))
		return;
#endif
	pcib_xlate_ari(dev, b, &s, &f);
	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_MSIX)
		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);
}

/* Pass request for device power state up to parent bridge. */
int
pcib_power_for_sleep(device_t pcib, device_t dev, int *pstate)
{
	device_t bus;

	bus = device_get_parent(pcib);
	return (PCIB_POWER_FOR_SLEEP(bus, dev, pstate));
}

static int
pcib_ari_enabled(device_t pcib)
{
	struct pcib_softc *sc;

	sc = device_get_softc(pcib);

	return ((sc->flags & PCIB_ENABLE_ARI) != 0);
}

static int
pcib_ari_get_id(device_t pcib, device_t dev, enum pci_id_type type,
    uintptr_t *id)
{
	struct pcib_softc *sc;
	device_t bus_dev;
	uint8_t bus, slot, func;

	if (type != PCI_ID_RID) {
		bus_dev = device_get_parent(pcib);
		return (PCIB_GET_ID(device_get_parent(bus_dev), dev, type, id));
	}

	sc = device_get_softc(pcib);

	if (sc->flags & PCIB_ENABLE_ARI) {
		bus = pci_get_bus(dev);
		func = pci_get_function(dev);

		*id = (PCI_ARI_RID(bus, func));
	} else {
		bus = pci_get_bus(dev);
		slot = pci_get_slot(dev);
		func = pci_get_function(dev);

		*id = (PCI_RID(bus, slot, func));
	}

	return (0);
}

/*
 * Check that the downstream port (pcib) and the endpoint device (dev) both
 * support ARI.  If so, enable it and return 0, otherwise return an error.
 */
static int
pcib_try_enable_ari(device_t pcib, device_t dev)
{
	struct pcib_softc *sc;
	int error;
	uint32_t cap2;
	int ari_cap_off;
	uint32_t ari_ver;
	uint32_t pcie_pos;

	sc = device_get_softc(pcib);

	/*
	 * ARI is controlled in a register in the PCIe capability structure.
	 * If the downstream port does not have the PCIe capability structure
	 * then it does not support ARI.
	 */
	error = pci_find_cap(pcib, PCIY_EXPRESS, &pcie_pos);
	if (error != 0)
		return (ENODEV);

	/* Check that the PCIe port advertises ARI support. */
	cap2 = pci_read_config(pcib, pcie_pos + PCIER_DEVICE_CAP2, 4);
	if (!(cap2 & PCIEM_CAP2_ARI))
		return (ENODEV);

	/*
	 * Check that the endpoint device advertises ARI support via the ARI
	 * extended capability structure.
	 */
	error = pci_find_extcap(dev, PCIZ_ARI, &ari_cap_off);
	if (error != 0)
		return (ENODEV);

	/*
	 * Finally, check that the endpoint device supports the same version
	 * of ARI that we do.
	 */
	ari_ver = pci_read_config(dev, ari_cap_off, 4);
	if (PCI_EXTCAP_VER(ari_ver) != PCIB_SUPPORTED_ARI_VER) {
		if (bootverbose)
			device_printf(pcib,
			    "Unsupported version of ARI (%d) detected\n",
			    PCI_EXTCAP_VER(ari_ver));

		return (ENXIO);
	}

	pcib_enable_ari(sc, pcie_pos);

	return (0);
}

int
pcib_request_feature_allow(device_t pcib, device_t dev,
    enum pci_feature feature)
{
	/*
	 * No host firmware we have to negotiate with, so we allow
	 * every valid feature requested.
	 */
	switch (feature) {
	case PCI_FEATURE_AER:
	case PCI_FEATURE_HP:
		break;
	default:
		return (EINVAL);
	}

	return (0);
}

int
pcib_request_feature(device_t dev, enum pci_feature feature)
{

	/*
	 * Invoke PCIB_REQUEST_FEATURE of this bridge first in case
	 * the firmware overrides the method of PCI-PCI bridges.
	 */
	return (PCIB_REQUEST_FEATURE(dev, dev, feature));
}

/*
 * Pass the request to use this PCI feature up the tree. Either there's a
 * firmware like ACPI that's using this feature that will approve (or deny) the
 * request to take it over, or the platform has no such firmware, in which case
 * the request will be approved. If the request is approved, the OS is expected
 * to make use of the feature or render it harmless.
 */
static int
pcib_request_feature_default(device_t pcib, device_t dev,
    enum pci_feature feature)
{
	device_t bus;

	/*
	 * Our parent is necessarily a pci bus. Its parent will either be
	 * another pci bridge (which passes it up) or a host bridge that can
	 * approve or reject the request.
	 */
	bus = device_get_parent(pcib);
	return (PCIB_REQUEST_FEATURE(device_get_parent(bus), dev, feature));
}