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Device layer rollup commit.

* cdevsw_add() is now required.  cdevsw_add() and cdevsw_remove() may specify
  a mask/match indicating the range of supported minor numbers.  Multiple
  cdevsw_add()'s using the same major number, but distinctly different
  ranges, may be issued.  All devices that failed to call cdevsw_add() before
  now do.

* cdevsw_remove() now automatically marks all devices within its supported
  range as being destroyed.

* vnode->v_rdev is no longer resolved when the vnode is created.  Instead,
  only v_udev (a newly added field) is resolved.  v_rdev is resolved when
  the vnode is opened and cleared on the last close.

* A great deal of code was making rather dubious assumptions with regards
  to the validity of devices associated with vnodes, primarily due to
  the persistence of a device structure due to being indexed by (major, minor)
  instead of by (cdevsw, major, minor).  In particular, if you run a program
  which connects to a USB device and then you pull the USB device and plug
  it back in, the vnode subsystem will continue to believe that the device
  is open when, in fact, it isn't (because it was destroyed and recreated).

  In particular, note that all the VFS mount procedures now check devices
  via v_udev instead of v_rdev prior to calling VOP_OPEN(), since v_rdev
  is NULL prior to the first open.

* The disk layer's device interaction has been rewritten.  The disk layer
  (i.e. the slice and disklabel management layer) no longer overloads
  its data onto the device structure representing the underlying physical
  disk.  Instead, the disk layer uses the new cdevsw_add() functionality
  to register its own cdevsw using the underlying device's major number,
  and simply does NOT register the underlying device's cdevsw.  No
  confusion is created because the device hash is now based on
  (cdevsw,major,minor) rather then (major,minor).

  NOTE: This also means that underlying raw disk devices may use the entire
  device minor number instead of having to reserve the bits used by the disk
  layer, and also means that can we (theoretically) stack a fully
  disklabel-supported 'disk' on top of any block device.

* The new reference counting scheme prevents this by associating a device
  with a cdevsw and disconnecting the device from its cdevsw when the cdevsw
  is removed.  Additionally, all udev2dev() lookups run through the cdevsw
  mask/match and only successfully find devices still associated with an
  active cdevsw.

* Major work on MFS:  MFS no longer shortcuts vnode and device creation.  It
  now creates a real vnode and a real device and implements real open and
  close VOPs.  Additionally, due to the disk layer changes, MFS is no longer
  limited to 255 mounts.  The new limit is 16 million.  Since MFS creates a
  real device node, mount_mfs will now create a real /dev/mfs<PID> device
  that can be read from userland (e.g. so you can dump an MFS filesystem).

* BUF AND DEVICE STRATEGY changes.  The struct buf contains a b_dev field.
  In order to properly handle stacked devices we now require that the b_dev
  field be initialized before the device strategy routine is called.  This
  required some additional work in various VFS implementations.  To enforce
  this requirement, biodone() now sets b_dev to NODEV.  The new disk layer
  will adjust b_dev before forwarding a request to the actual physical
  device.

* A bug in the ISO CD boot sequence which resulted in a panic has been fixed.

Testing by: lots of people, but David Rhodus found the most aggregious bugs.

/*
 * $NetBSD: usb.c,v 1.68 2002/02/20 20:30:12 christos Exp $
 * $FreeBSD: src/sys/dev/usb/usb.c,v 1.95 2003/11/09 23:54:21 joe Exp $
 * $DragonFly: src/sys/bus/usb/usb.c,v 1.14 2004/05/19 22:52:39 dillon Exp $
 */

/* Also already merged from NetBSD:
 *	$NetBSD: usb.c,v 1.70 2002/05/09 21:54:32 augustss Exp $
 *	$NetBSD: usb.c,v 1.71 2002/06/01 23:51:04 lukem Exp $
 *	$NetBSD: usb.c,v 1.73 2002/09/23 05:51:19 simonb Exp $
 */

/*
 * Copyright (c) 1998 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Lennart Augustsson (lennart@augustsson.net) at
 * Carlstedt Research & Technology.
 *
 * 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *        This product includes software developed by the NetBSD
 *        Foundation, Inc. and its contributors.
 * 4. Neither the name of The NetBSD Foundation nor the names of its
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
 */

/*
 * USB specifications and other documentation can be found at
 * http://www.usb.org/developers/data/ and
 * http://www.usb.org/developers/index.html .
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#if defined(__FreeBSD__) && __FreeBSD_version >= 500000
#include <sys/mutex.h>
#endif
#if defined(__NetBSD__) || defined(__OpenBSD__)
#include <sys/device.h>
#elif defined(__FreeBSD__) || defined(__DragonFly__)
#include <sys/unistd.h>
#include <sys/module.h>
#include <sys/bus.h>
#include <sys/filio.h>
#include <sys/uio.h>
#endif
#include <sys/kthread.h>
#include <sys/proc.h>
#include <sys/conf.h>
#include <sys/poll.h>
#if defined(__FreeBSD__) && __FreeBSD_version >= 500014
#include <sys/selinfo.h>
#else
#include <sys/select.h>
#endif
#include <sys/vnode.h>
#include <sys/signalvar.h>
#include <sys/sysctl.h>

#include "usb.h"
#include "usbdi.h"
#include "usbdi_util.h"

#define USBUNIT(d)	(minor(d))	/* usb_discover device nodes, kthread */
#define USB_DEV_MINOR	255		/* event queue device */

#if defined(__FreeBSD__) || defined(__DragonFly__)
MALLOC_DEFINE(M_USB, "USB", "USB");
MALLOC_DEFINE(M_USBDEV, "USBdev", "USB device");
MALLOC_DEFINE(M_USBHC, "USBHC", "USB host controller");

#include "usb_if.h"
#endif /* defined(__FreeBSD__) */

#include <machine/bus.h>

#include "usbdivar.h"
#include "usb_quirks.h"

/* Define this unconditionally in case a kernel module is loaded that
 * has been compiled with debugging options.
 */
SYSCTL_NODE(_hw, OID_AUTO, usb, CTLFLAG_RW, 0, "USB debugging");

#ifdef USB_DEBUG
#define DPRINTF(x)	if (usbdebug) logprintf x
#define DPRINTFN(n,x)	if (usbdebug>(n)) logprintf x
int	usbdebug = 0;
SYSCTL_INT(_hw_usb, OID_AUTO, debug, CTLFLAG_RW,
	   &usbdebug, 0, "usb debug level");
/*
 * 0  - do usual exploration
 * 1  - do not use timeout exploration
 * >1 - do no exploration
 */
int	usb_noexplore = 0;
#else
#define DPRINTF(x)
#define DPRINTFN(n,x)
#endif

struct usb_softc {
	USBBASEDEVICE	sc_dev;		/* base device */
	usbd_bus_handle sc_bus;		/* USB controller */
	struct usbd_port sc_port;	/* dummy port for root hub */

	struct thread	*sc_event_thread;

	char		sc_dying;
};

TAILQ_HEAD(, usb_task) usb_all_tasks;

#if defined(__NetBSD__) || defined(__OpenBSD__)
cdev_decl(usb);
#elif defined(__FreeBSD__) || defined(__DragonFly__)
d_open_t  usbopen;
d_close_t usbclose;
d_read_t usbread;
d_ioctl_t usbioctl;
int usbpoll(dev_t, int, usb_proc_ptr);

struct cdevsw usb_cdevsw = {
	/* name */      "usb",
	/* maj */       USB_CDEV_MAJOR,
	/* flags */     0,
	/* port */	NULL,
	/* clone */	NULL,

	/* open */      usbopen,
	/* close */     usbclose,
	/* read */      usbread,
	/* write */     nowrite,
	/* ioctl */     usbioctl,
	/* poll */      usbpoll,
	/* mmap */      nommap,
	/* strategy */  nostrategy,
	/* dump */      nodump,
	/* psize */     nopsize
};
#endif

Static void	usb_discover(void *);
Static void	usb_create_event_thread(void *);
Static void	usb_event_thread(void *);
Static void	usb_task_thread(void *);
Static usb_proc_ptr	usb_task_thread_proc = NULL;

#define USB_MAX_EVENTS 100
struct usb_event_q {
	struct usb_event ue;
	TAILQ_ENTRY(usb_event_q) next;
};
Static TAILQ_HEAD(, usb_event_q) usb_events =
	TAILQ_HEAD_INITIALIZER(usb_events);
Static int usb_nevents = 0;
Static struct selinfo usb_selevent;
Static struct proc *usb_async_proc;  /* process that wants USB SIGIO */
Static int usb_dev_open = 0;
Static void usb_add_event(int, struct usb_event *);

Static int usb_get_next_event(struct usb_event *);

#if defined(__NetBSD__) || defined(__OpenBSD__)
/* Flag to see if we are in the cold boot process. */
extern int cold;
#endif

Static const char *usbrev_str[] = USBREV_STR;

USB_DECLARE_DRIVER_INIT(usb,
			DEVMETHOD(device_suspend, bus_generic_suspend),
			DEVMETHOD(device_resume, bus_generic_resume),
			DEVMETHOD(device_shutdown, bus_generic_shutdown)
			);

#if defined(__FreeBSD__) || defined(__DragonFly__)
MODULE_VERSION(usb, 1);
#endif

USB_MATCH(usb)
{
	DPRINTF(("usbd_match\n"));
	return (UMATCH_GENERIC);
}

USB_ATTACH(usb)
{
#if defined(__NetBSD__) || defined(__OpenBSD__)
	struct usb_softc *sc = (struct usb_softc *)self;
#elif defined(__FreeBSD__) || defined(__DragonFly__)
	struct usb_softc *sc = device_get_softc(self);
	void *aux = device_get_ivars(self);
	static int global_init_done = 0;
#endif
	usbd_device_handle dev;
	usbd_status err;
	int usbrev;
	int speed;
	struct usb_event ue;

	sc->sc_dev = self;

	DPRINTF(("usbd_attach\n"));

	usbd_init();
	sc->sc_bus = aux;
	sc->sc_bus->usbctl = sc;
	sc->sc_port.power = USB_MAX_POWER;

#if defined(__FreeBSD__) || defined(__DragonFly__)
	printf("%s", USBDEVNAME(sc->sc_dev));
#endif
	usbrev = sc->sc_bus->usbrev;
	printf(": USB revision %s", usbrev_str[usbrev]);
	switch (usbrev) {
	case USBREV_1_0:
	case USBREV_1_1:
		speed = USB_SPEED_FULL;
		break;
	case USBREV_2_0:
		speed = USB_SPEED_HIGH;
		break;
	default:
		printf(", not supported\n");
		sc->sc_dying = 1;
		USB_ATTACH_ERROR_RETURN;
	}
	printf("\n");

	/* Make sure not to use tsleep() if we are cold booting. */
	if (cold)
		sc->sc_bus->use_polling++;

	ue.u.ue_ctrlr.ue_bus = USBDEVUNIT(sc->sc_dev);
	usb_add_event(USB_EVENT_CTRLR_ATTACH, &ue);

#ifdef USB_USE_SOFTINTR
#ifdef __HAVE_GENERIC_SOFT_INTERRUPTS
	/* XXX we should have our own level */
	sc->sc_bus->soft = softintr_establish(IPL_SOFTNET,
	    sc->sc_bus->methods->soft_intr, sc->sc_bus);
	if (sc->sc_bus->soft == NULL) {
		printf("%s: can't register softintr\n", USBDEVNAME(sc->sc_dev));
		sc->sc_dying = 1;
		USB_ATTACH_ERROR_RETURN;
	}
#else
	usb_callout_init(sc->sc_bus->softi);
#endif
#endif

	err = usbd_new_device(USBDEV(sc->sc_dev), sc->sc_bus, 0, speed, 0,
		  &sc->sc_port);
	if (!err) {
		dev = sc->sc_port.device;
		if (dev->hub == NULL) {
			sc->sc_dying = 1;
			printf("%s: root device is not a hub\n",
			       USBDEVNAME(sc->sc_dev));
			USB_ATTACH_ERROR_RETURN;
		}
		sc->sc_bus->root_hub = dev;
#if 1
		/*
		 * Turning this code off will delay attachment of USB devices
		 * until the USB event thread is running, which means that
		 * the keyboard will not work until after cold boot.
		 */
#if defined(__FreeBSD__) || defined(__DragonFly__)
		if (cold)
#else
		if (cold && (sc->sc_dev.dv_cfdata->cf_flags & 1))
#endif
			dev->hub->explore(sc->sc_bus->root_hub);
#endif
	} else {
		printf("%s: root hub problem, error=%d\n",
		       USBDEVNAME(sc->sc_dev), err);
		sc->sc_dying = 1;
	}
	if (cold)
		sc->sc_bus->use_polling--;

	config_pending_incr();
#if defined(__NetBSD__) || defined(__OpenBSD__)
	usb_kthread_create(usb_create_event_thread, sc);
#endif

#if defined(__FreeBSD__) || defined(__DragonFly__)
	usb_create_event_thread(sc);
	/* The per controller devices (used for usb_discover) */
	/* XXX This is redundant now, but old usbd's will want it */
	if (!global_init_done) {
		/* The device spitting out events */
		cdevsw_add(&usb_cdevsw, -1, USB_DEV_MINOR);
		make_dev(&usb_cdevsw, USB_DEV_MINOR, UID_ROOT, GID_OPERATOR,
			0660, "usb");
		global_init_done = 1;
	}
	cdevsw_add(&usb_cdevsw, -1, device_get_unit(self));
	make_dev(&usb_cdevsw, device_get_unit(self), UID_ROOT, GID_OPERATOR,
		0660, "usb%d", device_get_unit(self));
#endif

	USB_ATTACH_SUCCESS_RETURN;
}

void
usb_create_event_thread(void *arg)
{
	struct usb_softc *sc = arg;
	static int created = 0;

	if (usb_kthread_create1(usb_event_thread, sc, &sc->sc_event_thread,
			   "%s", USBDEVNAME(sc->sc_dev))) {
		printf("%s: unable to create event thread for\n",
		       USBDEVNAME(sc->sc_dev));
		panic("usb_create_event_thread");
	}
	if (!created) {
		created = 1;
		TAILQ_INIT(&usb_all_tasks);
		if (usb_kthread_create2(usb_task_thread, NULL,
					&usb_task_thread_proc, "usbtask")) {
			printf("unable to create task thread\n");
			panic("usb_create_event_thread task");
		}
	}
}

/*
 * Add a task to be performed by the task thread.  This function can be
 * called from any context and the task will be executed in a process
 * context ASAP.
 */
void
usb_add_task(usbd_device_handle dev, struct usb_task *task)
{
	int s;

	s = splusb();
	if (!task->onqueue) {
		DPRINTFN(2,("usb_add_task: task=%p\n", task));
		TAILQ_INSERT_TAIL(&usb_all_tasks, task, next);
		task->onqueue = 1;
	} else {
		DPRINTFN(3,("usb_add_task: task=%p on q\n", task));
	}
	wakeup(&usb_all_tasks);
	splx(s);
}

void
usb_rem_task(usbd_device_handle dev, struct usb_task *task)
{
	int s;

	s = splusb();
	if (task->onqueue) {
		TAILQ_REMOVE(&usb_all_tasks, task, next);
		task->onqueue = 0;
	}
	splx(s);
}

void
usb_event_thread(void *arg)
{
	struct usb_softc *sc = arg;

	DPRINTF(("usb_event_thread: start\n"));

	/*
	 * In case this controller is a companion controller to an
	 * EHCI controller we need to wait until the EHCI controller
	 * has grabbed the port.
	 * XXX It would be nicer to do this with a tsleep(), but I don't
	 * know how to synchronize the creation of the threads so it
	 * will work.
	 */
	usb_delay_ms(sc->sc_bus, 500);

	/* Make sure first discover does something. */
	sc->sc_bus->needs_explore = 1;
	usb_discover(sc);
	config_pending_decr();

	while (!sc->sc_dying) {
#ifdef USB_DEBUG
		if (usb_noexplore < 2)
#endif
		usb_discover(sc);
#ifdef USB_DEBUG
		(void)tsleep(&sc->sc_bus->needs_explore, 0, "usbevt",
			usb_noexplore ? 0 : hz * 60);
#else
		(void)tsleep(&sc->sc_bus->needs_explore, 0, "usbevt",
			hz * 60);
#endif
		DPRINTFN(2,("usb_event_thread: woke up\n"));
	}
	sc->sc_event_thread = NULL;

	/* In case parent is waiting for us to exit. */
	wakeup(sc);

	DPRINTF(("usb_event_thread: exit\n"));
	kthread_exit();
}

void
usb_task_thread(void *arg)
{
	struct usb_task *task;
	int s;

#if defined(__FreeBSD__) && __FreeBSD_version >= 500000
	mtx_lock(&Giant);
#endif

	DPRINTF(("usb_task_thread: start\n"));

	s = splusb();
	for (;;) {
		task = TAILQ_FIRST(&usb_all_tasks);
		if (task == NULL) {
			tsleep(&usb_all_tasks, 0, "usbtsk", 0);
			task = TAILQ_FIRST(&usb_all_tasks);
		}
		DPRINTFN(2,("usb_task_thread: woke up task=%p\n", task));
		if (task != NULL) {
			TAILQ_REMOVE(&usb_all_tasks, task, next);
			task->onqueue = 0;
			splx(s);
			task->fun(task->arg);
			s = splusb();
		}
	}
}

#if defined(__NetBSD__) || defined(__OpenBSD__)
int
usbctlprint(void *aux, const char *pnp)
{
	/* only "usb"es can attach to host controllers */
	if (pnp)
		printf("usb at %s", pnp);

	return (UNCONF);
}
#endif /* defined(__NetBSD__) || defined(__OpenBSD__) */

int
usbopen(dev_t dev, int flag, int mode, usb_proc_ptr p)
{
	int unit = USBUNIT(dev);
	struct usb_softc *sc;

	if (unit == USB_DEV_MINOR) {
		if (usb_dev_open)
			return (EBUSY);
		usb_dev_open = 1;
		usb_async_proc = NULL;
		return (0);
	}

	USB_GET_SC_OPEN(usb, unit, sc);

	if (sc->sc_dying)
		return (EIO);

	return (0);
}

int
usbread(dev_t dev, struct uio *uio, int flag)
{
	struct usb_event ue;
	int unit = USBUNIT(dev);
	int s, error, n;

	if (unit != USB_DEV_MINOR)
		return (ENODEV);

	if (uio->uio_resid != sizeof(struct usb_event))
		return (EINVAL);

	error = 0;
	s = splusb();
	for (;;) {
		n = usb_get_next_event(&ue);
		if (n != 0)
			break;
		if (flag & IO_NDELAY) {
			error = EWOULDBLOCK;
			break;
		}
		error = tsleep(&usb_events, PCATCH, "usbrea", 0);
		if (error)
			break;
	}
	splx(s);
	if (!error)
		error = uiomove((void *)&ue, uio->uio_resid, uio);

	return (error);
}

int
usbclose(dev_t dev, int flag, int mode, usb_proc_ptr p)
{
	int unit = USBUNIT(dev);

	if (unit == USB_DEV_MINOR) {
		usb_async_proc = NULL;
		usb_dev_open = 0;
	}

	return (0);
}

int
usbioctl(dev_t devt, u_long cmd, caddr_t data, int flag, usb_proc_ptr p)
{
	struct usb_softc *sc;
	int unit = USBUNIT(devt);

	if (unit == USB_DEV_MINOR) {
		switch (cmd) {
		case FIONBIO:
			/* All handled in the upper FS layer. */
			return (0);

		case FIOASYNC:
			if (*(int *)data)
#if defined(__DragonFly__)
				usb_async_proc = p->td_proc;
#elif __FreeBSD_version >= 500000
				usb_async_proc = p->td_proc;
#else
				usb_async_proc = p;
#endif
			else
				usb_async_proc = NULL;
			return (0);

		default:
			return (EINVAL);
		}
	}

	USB_GET_SC(usb, unit, sc);

	if (sc->sc_dying)
		return (EIO);

	switch (cmd) {
#if defined(__FreeBSD__) || defined(__DragonFly__)
	/* This part should be deleted */
  	case USB_DISCOVER:
  		break;
#endif
	case USB_REQUEST:
	{
		struct usb_ctl_request *ur = (void *)data;
		int len = UGETW(ur->ucr_request.wLength);
		struct iovec iov;
		struct uio uio;
		void *ptr = 0;
		int addr = ur->ucr_addr;
		usbd_status err;
		int error = 0;

		DPRINTF(("usbioctl: USB_REQUEST addr=%d len=%d\n", addr, len));
		if (len < 0 || len > 32768)
			return (EINVAL);
		if (addr < 0 || addr >= USB_MAX_DEVICES ||
		    sc->sc_bus->devices[addr] == 0)
			return (EINVAL);
		if (len != 0) {
			iov.iov_base = (caddr_t)ur->ucr_data;
			iov.iov_len = len;
			uio.uio_iov = &iov;
			uio.uio_iovcnt = 1;
			uio.uio_resid = len;
			uio.uio_offset = 0;
			uio.uio_segflg = UIO_USERSPACE;
			uio.uio_rw =
				ur->ucr_request.bmRequestType & UT_READ ?
				UIO_READ : UIO_WRITE;
			uio.uio_td = p;
			ptr = malloc(len, M_TEMP, M_WAITOK);
			if (uio.uio_rw == UIO_WRITE) {
				error = uiomove(ptr, len, &uio);
				if (error)
					goto ret;
			}
		}
		err = usbd_do_request_flags(sc->sc_bus->devices[addr],
			  &ur->ucr_request, ptr, ur->ucr_flags, &ur->ucr_actlen,
			  USBD_DEFAULT_TIMEOUT);
		if (err) {
			error = EIO;
			goto ret;
		}
		if (len != 0) {
			if (uio.uio_rw == UIO_READ) {
				error = uiomove(ptr, len, &uio);
				if (error)
					goto ret;
			}
		}
	ret:
		if (ptr)
			free(ptr, M_TEMP);
		return (error);
	}

	case USB_DEVICEINFO:
	{
		struct usb_device_info *di = (void *)data;
		int addr = di->udi_addr;
		usbd_device_handle dev;

		if (addr < 1 || addr >= USB_MAX_DEVICES)
			return (EINVAL);
		dev = sc->sc_bus->devices[addr];
		if (dev == NULL)
			return (ENXIO);
		usbd_fill_deviceinfo(dev, di, 1);
		break;
	}

	case USB_DEVICESTATS:
		*(struct usb_device_stats *)data = sc->sc_bus->stats;
		break;

	default:
		return (EINVAL);
	}
	return (0);
}

int
usbpoll(dev_t dev, int events, usb_proc_ptr p)
{
	int revents, mask, s;
	int unit = USBUNIT(dev);

	if (unit == USB_DEV_MINOR) {
		revents = 0;
		mask = POLLIN | POLLRDNORM;

		s = splusb();
		if (events & mask && usb_nevents > 0)
			revents |= events & mask;
		if (revents == 0 && events & mask)
			selrecord(p, &usb_selevent);
		splx(s);

		return (revents);
	} else {
#if defined(__FreeBSD__) || defined(__DragonFly__)
		return (0);	/* select/poll never wakes up - back compat */
#else
		return (ENXIO);
#endif
	}
}

/* Explore device tree from the root. */
Static void
usb_discover(void *v)
{
	struct usb_softc *sc = v;

#if defined(__FreeBSD__) || defined(__DragonFly__)
	/* splxxx should be changed to mutexes for preemption safety some day */
	int s;
#endif

	DPRINTFN(2,("usb_discover\n"));
#ifdef USB_DEBUG
	if (usb_noexplore > 1)
		return;
#endif

	/*
	 * We need mutual exclusion while traversing the device tree,
	 * but this is guaranteed since this function is only called
	 * from the event thread for the controller.
	 */
#if defined(__FreeBSD__) || defined(__DragonFly__)
	s = splusb();
#endif
	while (sc->sc_bus->needs_explore && !sc->sc_dying) {
		sc->sc_bus->needs_explore = 0;
#if defined(__FreeBSD__) || defined(__DragonFly__)
		splx(s);
#endif
		sc->sc_bus->root_hub->hub->explore(sc->sc_bus->root_hub);
#if defined(__FreeBSD__) || defined(__DragonFly__)
		s = splusb();
#endif
	}
#if defined(__FreeBSD__) || defined(__DragonFly__)
	splx(s);
#endif
}

void
usb_needs_explore(usbd_device_handle dev)
{
	DPRINTFN(2,("usb_needs_explore\n"));
	dev->bus->needs_explore = 1;
	wakeup(&dev->bus->needs_explore);
}

/* Called at splusb() */
int
usb_get_next_event(struct usb_event *ue)
{
	struct usb_event_q *ueq;

	if (usb_nevents <= 0)
		return (0);
	ueq = TAILQ_FIRST(&usb_events);
#ifdef DIAGNOSTIC
	if (ueq == NULL) {
		printf("usb: usb_nevents got out of sync! %d\n", usb_nevents);
		usb_nevents = 0;
		return (0);
	}
#endif
	*ue = ueq->ue;
	TAILQ_REMOVE(&usb_events, ueq, next);
	free(ueq, M_USBDEV);
	usb_nevents--;
	return (1);
}

void
usbd_add_dev_event(int type, usbd_device_handle udev)
{
	struct usb_event ue;

	usbd_fill_deviceinfo(udev, &ue.u.ue_device, USB_EVENT_IS_ATTACH(type));
	usb_add_event(type, &ue);
}

void
usbd_add_drv_event(int type, usbd_device_handle udev, device_ptr_t dev)
{
	struct usb_event ue;

	ue.u.ue_driver.ue_cookie = udev->cookie;
	strncpy(ue.u.ue_driver.ue_devname, USBDEVPTRNAME(dev),
		sizeof ue.u.ue_driver.ue_devname);
	usb_add_event(type, &ue);
}

void
usb_add_event(int type, struct usb_event *uep)
{
	struct usb_event_q *ueq;
	struct usb_event ue;
	struct timeval thetime;
	int s;

	ueq = malloc(sizeof *ueq, M_USBDEV, M_INTWAIT);
	ueq->ue = *uep;
	ueq->ue.ue_type = type;
	microtime(&thetime);
	TIMEVAL_TO_TIMESPEC(&thetime, &ueq->ue.ue_time);

	s = splusb();
	if (USB_EVENT_IS_DETACH(type)) {
		struct usb_event_q *ueqi, *ueqi_next;

		for (ueqi = TAILQ_FIRST(&usb_events); ueqi; ueqi = ueqi_next) {
			ueqi_next = TAILQ_NEXT(ueqi, next);
			if (ueqi->ue.u.ue_driver.ue_cookie.cookie ==
			    uep->u.ue_device.udi_cookie.cookie) {
				TAILQ_REMOVE(&usb_events, ueqi, next);
				free(ueqi, M_USBDEV);
				usb_nevents--;
				ueqi_next = TAILQ_FIRST(&usb_events);
			}
		}
	}
	if (usb_nevents >= USB_MAX_EVENTS) {
		/* Too many queued events, drop an old one. */
		DPRINTF(("usb: event dropped\n"));
		(void)usb_get_next_event(&ue);
	}
	TAILQ_INSERT_TAIL(&usb_events, ueq, next);
	usb_nevents++;
	wakeup(&usb_events);
	selwakeuppri(&usb_selevent, 0);
	if (usb_async_proc != NULL) {
		PROC_LOCK(usb_async_proc);
		psignal(usb_async_proc, SIGIO);
		PROC_UNLOCK(usb_async_proc);
	}
	splx(s);
}

void
usb_schedsoftintr(usbd_bus_handle bus)
{
	DPRINTFN(10,("usb_schedsoftintr: polling=%d\n", bus->use_polling));
#ifdef USB_USE_SOFTINTR
	if (bus->use_polling) {
		bus->methods->soft_intr(bus);
	} else {
#ifdef __HAVE_GENERIC_SOFT_INTERRUPTS
		softintr_schedule(bus->soft);
#else
		if (!callout_pending(&bus->softi))
			callout_reset(&bus->softi, 0, bus->methods->soft_intr,
			    bus);
#endif /* __HAVE_GENERIC_SOFT_INTERRUPTS */
	}
#else
	bus->methods->soft_intr(bus);
#endif /* USB_USE_SOFTINTR */
}


#if defined(__NetBSD__) || defined(__OpenBSD__)
int
usb_activate(device_ptr_t self, enum devact act)
{
	struct usb_softc *sc = (struct usb_softc *)self;
	usbd_device_handle dev = sc->sc_port.device;
	int i, rv = 0;

	switch (act) {
	case DVACT_ACTIVATE:
		return (EOPNOTSUPP);

	case DVACT_DEACTIVATE:
		sc->sc_dying = 1;
		if (dev != NULL && dev->cdesc != NULL && dev->subdevs != NULL) {
			for (i = 0; dev->subdevs[i]; i++)
				rv |= config_deactivate(dev->subdevs[i]);
		}
		break;
	}
	return (rv);
}

int
usb_detach(device_ptr_t self, int flags)
{
	struct usb_softc *sc = (struct usb_softc *)self;
	struct usb_event ue;

	DPRINTF(("usb_detach: start\n"));

	sc->sc_dying = 1;

	/* Make all devices disconnect. */
	if (sc->sc_port.device != NULL)
		usb_disconnect_port(&sc->sc_port, self);

	/* Kill off event thread. */
	if (sc->sc_event_thread != NULL) {
		wakeup(&sc->sc_bus->needs_explore);
		if (tsleep(sc, 0, "usbdet", hz * 60))
			printf("%s: event thread didn't die\n",
			       USBDEVNAME(sc->sc_dev));
		DPRINTF(("usb_detach: event thread dead\n"));
	}

	usbd_finish();

#ifdef USB_USE_SOFTINTR
#ifdef __HAVE_GENERIC_SOFT_INTERRUPTS
	if (sc->sc_bus->soft != NULL) {
		softintr_disestablish(sc->sc_bus->soft);
		sc->sc_bus->soft = NULL;
	}
#else
	callout_stop(&sc->sc_bus->softi);
#endif
#endif

	ue.u.ue_ctrlr.ue_bus = USBDEVUNIT(sc->sc_dev);
	usb_add_event(USB_EVENT_CTRLR_DETACH, &ue);

	return (0);
}
#elif defined(__FreeBSD__) || defined(__DragonFly__)
int
usb_detach(device_t self)
{
	DPRINTF(("%s: unload, prevented\n", USBDEVNAME(self)));

	return (EINVAL);
}
#endif


#if defined(__FreeBSD__) || defined(__DragonFly__)
DRIVER_MODULE(usb, ohci, usb_driver, usb_devclass, 0, 0);
DRIVER_MODULE(usb, uhci, usb_driver, usb_devclass, 0, 0);
DRIVER_MODULE(usb, ehci, usb_driver, usb_devclass, 0, 0);
#endif