Move files to match FreeBSD layout

1 files changed, 4588 insertions, 0 deletions

diff --git a/freebsd/sys/kern/subr_bus.c b/freebsd/sys/kern/subr_bus.c
new file mode 100644
index 00000000..9edbe777
--- /dev/null
+++ b/freebsd/sys/kern/subr_bus.c
@@ -0,0 +1,4588 @@
+#include <freebsd/machine/rtems-bsd-config.h>
+
+/*-
+ * Copyright (c) 1997,1998,2003 Doug Rabson
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <freebsd/sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <freebsd/local/opt_bus.h>
+
+#include <freebsd/sys/param.h>
+#include <freebsd/sys/conf.h>
+#include <freebsd/sys/filio.h>
+#include <freebsd/sys/lock.h>
+#include <freebsd/sys/kernel.h>
+#include <freebsd/sys/kobj.h>
+#include <freebsd/sys/limits.h>
+#include <freebsd/sys/malloc.h>
+#include <freebsd/sys/module.h>
+#include <freebsd/sys/mutex.h>
+#include <freebsd/sys/poll.h>
+#include <freebsd/sys/proc.h>
+#include <freebsd/sys/condvar.h>
+#include <freebsd/sys/queue.h>
+#include <freebsd/machine/bus.h>
+#include <freebsd/sys/rman.h>
+#include <freebsd/sys/selinfo.h>
+#include <freebsd/sys/signalvar.h>
+#include <freebsd/sys/sysctl.h>
+#include <freebsd/sys/systm.h>
+#include <freebsd/sys/uio.h>
+#include <freebsd/sys/bus.h>
+#include <freebsd/sys/interrupt.h>
+
+#include <freebsd/machine/stdarg.h>
+
+#include <freebsd/vm/uma.h>
+
+SYSCTL_NODE(_hw, OID_AUTO, bus, CTLFLAG_RW, NULL, NULL);
+SYSCTL_NODE(, OID_AUTO, dev, CTLFLAG_RW, NULL, NULL);
+
+/*
+ * Used to attach drivers to devclasses.
+ */
+typedef struct driverlink *driverlink_t;
+struct driverlink {
+	kobj_class_t	driver;
+	TAILQ_ENTRY(driverlink) link;	/* list of drivers in devclass */
+	int		pass;
+	TAILQ_ENTRY(driverlink) passlink;
+};
+
+/*
+ * Forward declarations
+ */
+typedef TAILQ_HEAD(devclass_list, devclass) devclass_list_t;
+typedef TAILQ_HEAD(driver_list, driverlink) driver_list_t;
+typedef TAILQ_HEAD(device_list, device) device_list_t;
+
+struct devclass {
+	TAILQ_ENTRY(devclass) link;
+	devclass_t	parent;		/* parent in devclass hierarchy */
+	driver_list_t	drivers;     /* bus devclasses store drivers for bus */
+	char		*name;
+	device_t	*devices;	/* array of devices indexed by unit */
+	int		maxunit;	/* size of devices array */
+	int		flags;
+#define DC_HAS_CHILDREN		1
+
+#ifndef __rtems__
+	struct sysctl_ctx_list sysctl_ctx;
+	struct sysctl_oid *sysctl_tree;
+#endif /* __rtems__ */
+};
+
+/**
+ * @brief Implementation of device.
+ */
+struct device {
+	/*
+	 * A device is a kernel object. The first field must be the
+	 * current ops table for the object.
+	 */
+	KOBJ_FIELDS;
+
+	/*
+	 * Device hierarchy.
+	 */
+	TAILQ_ENTRY(device)	link;	/**< list of devices in parent */
+	TAILQ_ENTRY(device)	devlink; /**< global device list membership */
+	device_t	parent;		/**< parent of this device  */
+	device_list_t	children;	/**< list of child devices */
+
+	/*
+	 * Details of this device.
+	 */
+	driver_t	*driver;	/**< current driver */
+	devclass_t	devclass;	/**< current device class */
+	int		unit;		/**< current unit number */
+	char*		nameunit;	/**< name+unit e.g. foodev0 */
+	char*		desc;		/**< driver specific description */
+	int		busy;		/**< count of calls to device_busy() */
+	device_state_t	state;		/**< current device state  */
+	u_int32_t	devflags;	/**< api level flags for device_get_flags() */
+	u_int		flags;		/**< internal device flags  */
+#define	DF_ENABLED	0x01		/* device should be probed/attached */
+#define	DF_FIXEDCLASS	0x02		/* devclass specified at create time */
+#define	DF_WILDCARD	0x04		/* unit was originally wildcard */
+#define	DF_DESCMALLOCED	0x08		/* description was malloced */
+#define	DF_QUIET	0x10		/* don't print verbose attach message */
+#define	DF_DONENOMATCH	0x20		/* don't execute DEVICE_NOMATCH again */
+#define	DF_EXTERNALSOFTC 0x40		/* softc not allocated by us */
+#define	DF_REBID	0x80		/* Can rebid after attach */
+	u_int	order;			/**< order from device_add_child_ordered() */
+	void	*ivars;			/**< instance variables  */
+	void	*softc;			/**< current driver's variables  */
+
+#ifndef __rtems__
+	struct sysctl_ctx_list sysctl_ctx; /**< state for sysctl variables  */
+	struct sysctl_oid *sysctl_tree;	/**< state for sysctl variables */
+#endif /* __rtems__ */
+};
+
+static MALLOC_DEFINE(M_BUS, "bus", "Bus data structures");
+static MALLOC_DEFINE(M_BUS_SC, "bus-sc", "Bus data structures, softc");
+
+#ifdef BUS_DEBUG
+
+static int bus_debug = 1;
+#ifndef __rtems__
+TUNABLE_INT("bus.debug", &bus_debug);
+SYSCTL_INT(_debug, OID_AUTO, bus_debug, CTLFLAG_RW, &bus_debug, 0,
+    "Debug bus code");
+#endif /* __rtems__ */
+
+#define PDEBUG(a)	if (bus_debug) {printf("%s:%d: ", __func__, __LINE__), printf a; printf("\n");}
+#define DEVICENAME(d)	((d)? device_get_name(d): "no device")
+#define DRIVERNAME(d)	((d)? d->name : "no driver")
+#define DEVCLANAME(d)	((d)? d->name : "no devclass")
+
+/**
+ * Produce the indenting, indent*2 spaces plus a '.' ahead of that to
+ * prevent syslog from deleting initial spaces
+ */
+#define indentprintf(p)	do { int iJ; printf("."); for (iJ=0; iJ<indent; iJ++) printf("  "); printf p ; } while (0)
+
+static void print_device_short(device_t dev, int indent);
+static void print_device(device_t dev, int indent);
+void print_device_tree_short(device_t dev, int indent);
+void print_device_tree(device_t dev, int indent);
+static void print_driver_short(driver_t *driver, int indent);
+static void print_driver(driver_t *driver, int indent);
+static void print_driver_list(driver_list_t drivers, int indent);
+static void print_devclass_short(devclass_t dc, int indent);
+static void print_devclass(devclass_t dc, int indent);
+void print_devclass_list_short(void);
+void print_devclass_list(void);
+
+#else
+/* Make the compiler ignore the function calls */
+#define PDEBUG(a)			/* nop */
+#define DEVICENAME(d)			/* nop */
+#define DRIVERNAME(d)			/* nop */
+#define DEVCLANAME(d)			/* nop */
+
+#define print_device_short(d,i)		/* nop */
+#define print_device(d,i)		/* nop */
+#define print_device_tree_short(d,i)	/* nop */
+#define print_device_tree(d,i)		/* nop */
+#define print_driver_short(d,i)		/* nop */
+#define print_driver(d,i)		/* nop */
+#define print_driver_list(d,i)		/* nop */
+#define print_devclass_short(d,i)	/* nop */
+#define print_devclass(d,i)		/* nop */
+#define print_devclass_list_short()	/* nop */
+#define print_devclass_list()		/* nop */
+#endif
+
+#ifndef __rtems__
+/*
+ * dev sysctl tree
+ */
+
+enum {
+	DEVCLASS_SYSCTL_PARENT,
+};
+
+static int
+devclass_sysctl_handler(SYSCTL_HANDLER_ARGS)
+{
+	devclass_t dc = (devclass_t)arg1;
+	const char *value;
+
+	switch (arg2) {
+	case DEVCLASS_SYSCTL_PARENT:
+		value = dc->parent ? dc->parent->name : "";
+		break;
+	default:
+		return (EINVAL);
+	}
+	return (SYSCTL_OUT(req, value, strlen(value)));
+}
+
+static void
+devclass_sysctl_init(devclass_t dc)
+{
+
+	if (dc->sysctl_tree != NULL)
+		return;
+	sysctl_ctx_init(&dc->sysctl_ctx);
+	dc->sysctl_tree = SYSCTL_ADD_NODE(&dc->sysctl_ctx,
+	    SYSCTL_STATIC_CHILDREN(_dev), OID_AUTO, dc->name,
+	    CTLFLAG_RD, NULL, "");
+	SYSCTL_ADD_PROC(&dc->sysctl_ctx, SYSCTL_CHILDREN(dc->sysctl_tree),
+	    OID_AUTO, "%parent", CTLFLAG_RD,
+	    dc, DEVCLASS_SYSCTL_PARENT, devclass_sysctl_handler, "A",
+	    "parent class");
+}
+
+enum {
+	DEVICE_SYSCTL_DESC,
+	DEVICE_SYSCTL_DRIVER,
+	DEVICE_SYSCTL_LOCATION,
+	DEVICE_SYSCTL_PNPINFO,
+	DEVICE_SYSCTL_PARENT,
+};
+
+static int
+device_sysctl_handler(SYSCTL_HANDLER_ARGS)
+{
+	device_t dev = (device_t)arg1;
+	const char *value;
+	char *buf;
+	int error;
+
+	buf = NULL;
+	switch (arg2) {
+	case DEVICE_SYSCTL_DESC:
+		value = dev->desc ? dev->desc : "";
+		break;
+	case DEVICE_SYSCTL_DRIVER:
+		value = dev->driver ? dev->driver->name : "";
+		break;
+	case DEVICE_SYSCTL_LOCATION:
+		value = buf = malloc(1024, M_BUS, M_WAITOK | M_ZERO);
+		bus_child_location_str(dev, buf, 1024);
+		break;
+	case DEVICE_SYSCTL_PNPINFO:
+		value = buf = malloc(1024, M_BUS, M_WAITOK | M_ZERO);
+		bus_child_pnpinfo_str(dev, buf, 1024);
+		break;
+	case DEVICE_SYSCTL_PARENT:
+		value = dev->parent ? dev->parent->nameunit : "";
+		break;
+	default:
+		return (EINVAL);
+	}
+	error = SYSCTL_OUT(req, value, strlen(value));
+	if (buf != NULL)
+		free(buf, M_BUS);
+	return (error);
+}
+#endif /* __rtems__ */
+
+static void
+device_sysctl_init(device_t dev)
+{
+#ifndef __rtems__
+	devclass_t dc = dev->devclass;
+
+	if (dev->sysctl_tree != NULL)
+		return;
+	devclass_sysctl_init(dc);
+	sysctl_ctx_init(&dev->sysctl_ctx);
+	dev->sysctl_tree = SYSCTL_ADD_NODE(&dev->sysctl_ctx,
+	    SYSCTL_CHILDREN(dc->sysctl_tree), OID_AUTO,
+	    dev->nameunit + strlen(dc->name),
+	    CTLFLAG_RD, NULL, "");
+	SYSCTL_ADD_PROC(&dev->sysctl_ctx, SYSCTL_CHILDREN(dev->sysctl_tree),
+	    OID_AUTO, "%desc", CTLFLAG_RD,
+	    dev, DEVICE_SYSCTL_DESC, device_sysctl_handler, "A",
+	    "device description");
+	SYSCTL_ADD_PROC(&dev->sysctl_ctx, SYSCTL_CHILDREN(dev->sysctl_tree),
+	    OID_AUTO, "%driver", CTLFLAG_RD,
+	    dev, DEVICE_SYSCTL_DRIVER, device_sysctl_handler, "A",
+	    "device driver name");
+	SYSCTL_ADD_PROC(&dev->sysctl_ctx, SYSCTL_CHILDREN(dev->sysctl_tree),
+	    OID_AUTO, "%location", CTLFLAG_RD,
+	    dev, DEVICE_SYSCTL_LOCATION, device_sysctl_handler, "A",
+	    "device location relative to parent");
+	SYSCTL_ADD_PROC(&dev->sysctl_ctx, SYSCTL_CHILDREN(dev->sysctl_tree),
+	    OID_AUTO, "%pnpinfo", CTLFLAG_RD,
+	    dev, DEVICE_SYSCTL_PNPINFO, device_sysctl_handler, "A",
+	    "device identification");
+	SYSCTL_ADD_PROC(&dev->sysctl_ctx, SYSCTL_CHILDREN(dev->sysctl_tree),
+	    OID_AUTO, "%parent", CTLFLAG_RD,
+	    dev, DEVICE_SYSCTL_PARENT, device_sysctl_handler, "A",
+	    "parent device");
+#endif /* __rtems__ */
+}
+
+static void
+device_sysctl_update(device_t dev)
+{
+#ifndef __rtems__
+	devclass_t dc = dev->devclass;
+
+	if (dev->sysctl_tree == NULL)
+		return;
+	sysctl_rename_oid(dev->sysctl_tree, dev->nameunit + strlen(dc->name));
+#endif /* __rtems__ */
+}
+
+static void
+device_sysctl_fini(device_t dev)
+{
+#ifndef __rtems__
+	if (dev->sysctl_tree == NULL)
+		return;
+	sysctl_ctx_free(&dev->sysctl_ctx);
+	dev->sysctl_tree = NULL;
+#endif /* __rtems__ */
+}
+
+/*
+ * /dev/devctl implementation
+ */
+
+/*
+ * This design allows only one reader for /dev/devctl.  This is not desirable
+ * in the long run, but will get a lot of hair out of this implementation.
+ * Maybe we should make this device a clonable device.
+ *
+ * Also note: we specifically do not attach a device to the device_t tree
+ * to avoid potential chicken and egg problems.  One could argue that all
+ * of this belongs to the root node.  One could also further argue that the
+ * sysctl interface that we have not might more properly be an ioctl
+ * interface, but at this stage of the game, I'm not inclined to rock that
+ * boat.
+ *
+ * I'm also not sure that the SIGIO support is done correctly or not, as
+ * I copied it from a driver that had SIGIO support that likely hasn't been
+ * tested since 3.4 or 2.2.8!
+ */
+
+#ifndef __rtems__
+/* Deprecated way to adjust queue length */
+static int sysctl_devctl_disable(SYSCTL_HANDLER_ARGS);
+/* XXX Need to support old-style tunable hw.bus.devctl_disable" */
+SYSCTL_PROC(_hw_bus, OID_AUTO, devctl_disable, CTLTYPE_INT | CTLFLAG_RW, NULL,
+    0, sysctl_devctl_disable, "I", "devctl disable -- deprecated");
+#endif /* __rtems__ */
+
+#define DEVCTL_DEFAULT_QUEUE_LEN 1000
+#ifndef __rtems__
+static int sysctl_devctl_queue(SYSCTL_HANDLER_ARGS);
+#endif /* __rtems__ */
+static int devctl_queue_length = DEVCTL_DEFAULT_QUEUE_LEN;
+#ifndef __rtems__
+TUNABLE_INT("hw.bus.devctl_queue", &devctl_queue_length);
+SYSCTL_PROC(_hw_bus, OID_AUTO, devctl_queue, CTLTYPE_INT | CTLFLAG_RW, NULL,
+    0, sysctl_devctl_queue, "I", "devctl queue length");
+
+static d_open_t		devopen;
+static d_close_t	devclose;
+static d_read_t		devread;
+static d_ioctl_t	devioctl;
+static d_poll_t		devpoll;
+
+static struct cdevsw dev_cdevsw = {
+	.d_version =	D_VERSION,
+	.d_flags =	D_NEEDGIANT,
+	.d_open =	devopen,
+	.d_close =	devclose,
+	.d_read =	devread,
+	.d_ioctl =	devioctl,
+	.d_poll =	devpoll,
+	.d_name =	"devctl",
+};
+
+struct dev_event_info
+{
+	char *dei_data;
+	TAILQ_ENTRY(dev_event_info) dei_link;
+};
+
+TAILQ_HEAD(devq, dev_event_info);
+
+static struct dev_softc
+{
+	int	inuse;
+	int	nonblock;
+	int	queued;
+	struct mtx mtx;
+	struct cv cv;
+	struct selinfo sel;
+	struct devq devq;
+	struct proc *async_proc;
+} devsoftc;
+
+static struct cdev *devctl_dev;
+#else /* __rtems__ */
+#define devctl_disable 0
+#endif /* __rtems__ */
+
+static void
+devinit(void)
+{
+#ifndef __rtems__
+	devctl_dev = make_dev(&dev_cdevsw, 0, UID_ROOT, GID_WHEEL, 0600,
+	    "devctl");
+	mtx_init(&devsoftc.mtx, "dev mtx", "devd", MTX_DEF);
+	cv_init(&devsoftc.cv, "dev cv");
+	TAILQ_INIT(&devsoftc.devq);
+#endif /* __rtems__ */
+}
+
+#ifndef __rtems__
+static int
+devopen(struct cdev *dev, int oflags, int devtype, struct thread *td)
+{
+	if (devsoftc.inuse)
+		return (EBUSY);
+	/* move to init */
+	devsoftc.inuse = 1;
+	devsoftc.nonblock = 0;
+	devsoftc.async_proc = NULL;
+	return (0);
+}
+
+static int
+devclose(struct cdev *dev, int fflag, int devtype, struct thread *td)
+{
+	devsoftc.inuse = 0;
+	mtx_lock(&devsoftc.mtx);
+	cv_broadcast(&devsoftc.cv);
+	mtx_unlock(&devsoftc.mtx);
+	devsoftc.async_proc = NULL;
+	return (0);
+}
+
+/*
+ * The read channel for this device is used to report changes to
+ * userland in realtime.  We are required to free the data as well as
+ * the n1 object because we allocate them separately.  Also note that
+ * we return one record at a time.  If you try to read this device a
+ * character at a time, you will lose the rest of the data.  Listening
+ * programs are expected to cope.
+ */
+static int
+devread(struct cdev *dev, struct uio *uio, int ioflag)
+{
+	struct dev_event_info *n1;
+	int rv;
+
+	mtx_lock(&devsoftc.mtx);
+	while (TAILQ_EMPTY(&devsoftc.devq)) {
+		if (devsoftc.nonblock) {
+			mtx_unlock(&devsoftc.mtx);
+			return (EAGAIN);
+		}
+		rv = cv_wait_sig(&devsoftc.cv, &devsoftc.mtx);
+		if (rv) {
+			/*
+			 * Need to translate ERESTART to EINTR here? -- jake
+			 */
+			mtx_unlock(&devsoftc.mtx);
+			return (rv);
+		}
+	}
+	n1 = TAILQ_FIRST(&devsoftc.devq);
+	TAILQ_REMOVE(&devsoftc.devq, n1, dei_link);
+	devsoftc.queued--;
+	mtx_unlock(&devsoftc.mtx);
+	rv = uiomove(n1->dei_data, strlen(n1->dei_data), uio);
+	free(n1->dei_data, M_BUS);
+	free(n1, M_BUS);
+	return (rv);
+}
+
+static	int
+devioctl(struct cdev *dev, u_long cmd, caddr_t data, int fflag, struct thread *td)
+{
+	switch (cmd) {
+
+	case FIONBIO:
+		if (*(int*)data)
+			devsoftc.nonblock = 1;
+		else
+			devsoftc.nonblock = 0;
+		return (0);
+	case FIOASYNC:
+		if (*(int*)data)
+			devsoftc.async_proc = td->td_proc;
+		else
+			devsoftc.async_proc = NULL;
+		return (0);
+
+		/* (un)Support for other fcntl() calls. */
+	case FIOCLEX:
+	case FIONCLEX:
+	case FIONREAD:
+	case FIOSETOWN:
+	case FIOGETOWN:
+	default:
+		break;
+	}
+	return (ENOTTY);
+}
+
+static	int
+devpoll(struct cdev *dev, int events, struct thread *td)
+{
+	int	revents = 0;
+
+	mtx_lock(&devsoftc.mtx);
+	if (events & (POLLIN | POLLRDNORM)) {
+		if (!TAILQ_EMPTY(&devsoftc.devq))
+			revents = events & (POLLIN | POLLRDNORM);
+		else
+			selrecord(td, &devsoftc.sel);
+	}
+	mtx_unlock(&devsoftc.mtx);
+
+	return (revents);
+}
+
+/**
+ * @brief Return whether the userland process is running
+ */
+boolean_t
+devctl_process_running(void)
+{
+	return (devsoftc.inuse == 1);
+}
+#endif /* __rtems__ */
+
+/**
+ * @brief Queue data to be read from the devctl device
+ *
+ * Generic interface to queue data to the devctl device.  It is
+ * assumed that @p data is properly formatted.  It is further assumed
+ * that @p data is allocated using the M_BUS malloc type.
+ */
+void
+devctl_queue_data_f(char *data, int flags)
+{
+#ifndef __rtems__
+	struct dev_event_info *n1 = NULL, *n2 = NULL;
+	struct proc *p;
+#endif /* __rtems__ */
+
+	if (strlen(data) == 0)
+		goto out;
+#ifndef __rtems__
+	if (devctl_queue_length == 0)
+		goto out;
+	n1 = malloc(sizeof(*n1), M_BUS, flags);
+	if (n1 == NULL)
+		goto out;
+	n1->dei_data = data;
+	mtx_lock(&devsoftc.mtx);
+	if (devctl_queue_length == 0) {
+		mtx_unlock(&devsoftc.mtx);
+		free(n1->dei_data, M_BUS);
+		free(n1, M_BUS);
+		return;
+	}
+	/* Leave at least one spot in the queue... */
+	while (devsoftc.queued > devctl_queue_length - 1) {
+		n2 = TAILQ_FIRST(&devsoftc.devq);
+		TAILQ_REMOVE(&devsoftc.devq, n2, dei_link);
+		free(n2->dei_data, M_BUS);
+		free(n2, M_BUS);
+		devsoftc.queued--;
+	}
+	TAILQ_INSERT_TAIL(&devsoftc.devq, n1, dei_link);
+	devsoftc.queued++;
+	cv_broadcast(&devsoftc.cv);
+	mtx_unlock(&devsoftc.mtx);
+	selwakeup(&devsoftc.sel);
+	p = devsoftc.async_proc;
+	if (p != NULL) {
+		PROC_LOCK(p);
+		psignal(p, SIGIO);
+		PROC_UNLOCK(p);
+	}
+#else /* __rtems__ */
+	printf("devctl: %s", data);
+#endif /* __rtems__ */
+out:
+	/*
+	 * We have to free data on all error paths since the caller
+	 * assumes it will be free'd when this item is dequeued.
+	 */
+	free(data, M_BUS);
+	return;
+}
+
+void
+devctl_queue_data(char *data)
+{
+
+	devctl_queue_data_f(data, M_NOWAIT);
+}
+
+/**
+ * @brief Send a 'notification' to userland, using standard ways
+ */
+void
+devctl_notify_f(const char *system, const char *subsystem, const char *type,
+    const char *data, int flags)
+{
+	int len = 0;
+	char *msg;
+
+	if (system == NULL)
+		return;		/* BOGUS!  Must specify system. */
+	if (subsystem == NULL)
+		return;		/* BOGUS!  Must specify subsystem. */
+	if (type == NULL)
+		return;		/* BOGUS!  Must specify type. */
+	len += strlen(" system=") + strlen(system);
+	len += strlen(" subsystem=") + strlen(subsystem);
+	len += strlen(" type=") + strlen(type);
+	/* add in the data message plus newline. */
+	if (data != NULL)
+		len += strlen(data);
+	len += 3;	/* '!', '\n', and NUL */
+	msg = malloc(len, M_BUS, flags);
+	if (msg == NULL)
+		return;		/* Drop it on the floor */
+	if (data != NULL)
+		snprintf(msg, len, "!system=%s subsystem=%s type=%s %s\n",
+		    system, subsystem, type, data);
+	else
+		snprintf(msg, len, "!system=%s subsystem=%s type=%s\n",
+		    system, subsystem, type);
+	devctl_queue_data_f(msg, flags);
+}
+
+void
+devctl_notify(const char *system, const char *subsystem, const char *type,
+    const char *data)
+{
+
+	devctl_notify_f(system, subsystem, type, data, M_NOWAIT);
+}
+
+/*
+ * Common routine that tries to make sending messages as easy as possible.
+ * We allocate memory for the data, copy strings into that, but do not
+ * free it unless there's an error.  The dequeue part of the driver should
+ * free the data.  We don't send data when the device is disabled.  We do
+ * send data, even when we have no listeners, because we wish to avoid
+ * races relating to startup and restart of listening applications.
+ *
+ * devaddq is designed to string together the type of event, with the
+ * object of that event, plus the plug and play info and location info
+ * for that event.  This is likely most useful for devices, but less
+ * useful for other consumers of this interface.  Those should use
+ * the devctl_queue_data() interface instead.
+ */
+static void
+devaddq(const char *type, const char *what, device_t dev)
+{
+	char *data = NULL;
+	char *loc = NULL;
+	char *pnp = NULL;
+	const char *parstr;
+
+	if (!devctl_queue_length)/* Rare race, but lost races safely discard */
+		return;
+	data = malloc(1024, M_BUS, M_NOWAIT);
+	if (data == NULL)
+		goto bad;
+
+	/* get the bus specific location of this device */
+	loc = malloc(1024, M_BUS, M_NOWAIT);
+	if (loc == NULL)
+		goto bad;
+	*loc = '\0';
+	bus_child_location_str(dev, loc, 1024);
+
+	/* Get the bus specific pnp info of this device */
+	pnp = malloc(1024, M_BUS, M_NOWAIT);
+	if (pnp == NULL)
+		goto bad;
+	*pnp = '\0';
+	bus_child_pnpinfo_str(dev, pnp, 1024);
+
+	/* Get the parent of this device, or / if high enough in the tree. */
+	if (device_get_parent(dev) == NULL)
+		parstr = ".";	/* Or '/' ? */
+	else
+		parstr = device_get_nameunit(device_get_parent(dev));
+	/* String it all together. */
+	snprintf(data, 1024, "%s%s at %s %s on %s\n", type, what, loc, pnp,
+	  parstr);
+	free(loc, M_BUS);
+	free(pnp, M_BUS);
+	devctl_queue_data(data);
+	return;
+bad:
+	free(pnp, M_BUS);
+	free(loc, M_BUS);
+	free(data, M_BUS);
+	return;
+}
+
+/*
+ * A device was added to the tree.  We are called just after it successfully
+ * attaches (that is, probe and attach success for this device).  No call
+ * is made if a device is merely parented into the tree.  See devnomatch
+ * if probe fails.  If attach fails, no notification is sent (but maybe
+ * we should have a different message for this).
+ */
+static void
+devadded(device_t dev)
+{
+	char *pnp = NULL;
+	char *tmp = NULL;
+
+	pnp = malloc(1024, M_BUS, M_NOWAIT);
+	if (pnp == NULL)
+		goto fail;
+	tmp = malloc(1024, M_BUS, M_NOWAIT);
+	if (tmp == NULL)
+		goto fail;
+	*pnp = '\0';
+	bus_child_pnpinfo_str(dev, pnp, 1024);
+	snprintf(tmp, 1024, "%s %s", device_get_nameunit(dev), pnp);
+	devaddq("+", tmp, dev);
+fail:
+	if (pnp != NULL)
+		free(pnp, M_BUS);
+	if (tmp != NULL)
+		free(tmp, M_BUS);
+	return;
+}
+
+/*
+ * A device was removed from the tree.  We are called just before this
+ * happens.
+ */
+static void
+devremoved(device_t dev)
+{
+	char *pnp = NULL;
+	char *tmp = NULL;
+
+	pnp = malloc(1024, M_BUS, M_NOWAIT);
+	if (pnp == NULL)
+		goto fail;
+	tmp = malloc(1024, M_BUS, M_NOWAIT);
+	if (tmp == NULL)
+		goto fail;
+	*pnp = '\0';
+	bus_child_pnpinfo_str(dev, pnp, 1024);
+	snprintf(tmp, 1024, "%s %s", device_get_nameunit(dev), pnp);
+	devaddq("-", tmp, dev);
+fail:
+	if (pnp != NULL)
+		free(pnp, M_BUS);
+	if (tmp != NULL)
+		free(tmp, M_BUS);
+	return;
+}
+
+/*
+ * Called when there's no match for this device.  This is only called
+ * the first time that no match happens, so we don't keep getting this
+ * message.  Should that prove to be undesirable, we can change it.
+ * This is called when all drivers that can attach to a given bus
+ * decline to accept this device.  Other errrors may not be detected.
+ */
+static void
+devnomatch(device_t dev)
+{
+	devaddq("?", "", dev);
+}
+
+#ifndef __rtems__
+static int
+sysctl_devctl_disable(SYSCTL_HANDLER_ARGS)
+{
+	struct dev_event_info *n1;
+	int dis, error;
+
+	dis = devctl_queue_length == 0;
+	error = sysctl_handle_int(oidp, &dis, 0, req);
+	if (error || !req->newptr)
+		return (error);
+	mtx_lock(&devsoftc.mtx);
+	if (dis) {
+		while (!TAILQ_EMPTY(&devsoftc.devq)) {
+			n1 = TAILQ_FIRST(&devsoftc.devq);
+			TAILQ_REMOVE(&devsoftc.devq, n1, dei_link);
+			free(n1->dei_data, M_BUS);
+			free(n1, M_BUS);
+		}
+		devsoftc.queued = 0;
+		devctl_queue_length = 0;
+	} else {
+		devctl_queue_length = DEVCTL_DEFAULT_QUEUE_LEN;
+	}
+	mtx_unlock(&devsoftc.mtx);
+	return (0);
+}
+
+static int
+sysctl_devctl_queue(SYSCTL_HANDLER_ARGS)
+{
+	struct dev_event_info *n1;
+	int q, error;
+
+	q = devctl_queue_length;
+	error = sysctl_handle_int(oidp, &q, 0, req);
+	if (error || !req->newptr)
+		return (error);
+	if (q < 0)
+		return (EINVAL);
+	mtx_lock(&devsoftc.mtx);
+	devctl_queue_length = q;
+	while (devsoftc.queued > devctl_queue_length) {
+		n1 = TAILQ_FIRST(&devsoftc.devq);
+		TAILQ_REMOVE(&devsoftc.devq, n1, dei_link);
+		free(n1->dei_data, M_BUS);
+		free(n1, M_BUS);
+		devsoftc.queued--;
+	}
+	mtx_unlock(&devsoftc.mtx);
+	return (0);
+}
+
+/* End of /dev/devctl code */
+#endif /* __rtems__ */
+
+static TAILQ_HEAD(,device)	bus_data_devices;
+static int bus_data_generation = 1;
+
+static kobj_method_t null_methods[] = {
+	KOBJMETHOD_END
+};
+
+DEFINE_CLASS(null, null_methods, 0);
+
+/*
+ * Bus pass implementation
+ */
+
+static driver_list_t passes = TAILQ_HEAD_INITIALIZER(passes);
+int bus_current_pass = BUS_PASS_ROOT;
+
+/**
+ * @internal
+ * @brief Register the pass level of a new driver attachment
+ *
+ * Register a new driver attachment's pass level.  If no driver
+ * attachment with the same pass level has been added, then @p new
+ * will be added to the global passes list.
+ *
+ * @param new		the new driver attachment
+ */
+static void
+driver_register_pass(struct driverlink *new)
+{
+	struct driverlink *dl;
+
+	/* We only consider pass numbers during boot. */
+	if (bus_current_pass == BUS_PASS_DEFAULT)
+		return;
+
+	/*
+	 * Walk the passes list.  If we already know about this pass
+	 * then there is nothing to do.  If we don't, then insert this
+	 * driver link into the list.
+	 */
+	TAILQ_FOREACH(dl, &passes, passlink) {
+		if (dl->pass < new->pass)
+			continue;
+		if (dl->pass == new->pass)
+			return;
+		TAILQ_INSERT_BEFORE(dl, new, passlink);
+		return;
+	}
+	TAILQ_INSERT_TAIL(&passes, new, passlink);
+}
+
+/**
+ * @brief Raise the current bus pass
+ *
+ * Raise the current bus pass level to @p pass.  Call the BUS_NEW_PASS()
+ * method on the root bus to kick off a new device tree scan for each
+ * new pass level that has at least one driver.
+ */
+void
+bus_set_pass(int pass)
+{
+	struct driverlink *dl;
+
+	if (bus_current_pass > pass)
+		panic("Attempt to lower bus pass level");
+
+	TAILQ_FOREACH(dl, &passes, passlink) {
+		/* Skip pass values below the current pass level. */
+		if (dl->pass <= bus_current_pass)
+			continue;
+
+		/*
+		 * Bail once we hit a driver with a pass level that is
+		 * too high.
+		 */
+		if (dl->pass > pass)
+			break;
+
+		/*
+		 * Raise the pass level to the next level and rescan
+		 * the tree.
+		 */
+		bus_current_pass = dl->pass;
+		BUS_NEW_PASS(root_bus);
+	}
+
+	/*
+	 * If there isn't a driver registered for the requested pass,
+	 * then bus_current_pass might still be less than 'pass'.  Set
+	 * it to 'pass' in that case.
+	 */
+	if (bus_current_pass < pass)
+		bus_current_pass = pass;
+	KASSERT(bus_current_pass == pass, ("Failed to update bus pass level"));
+}
+
+/*
+ * Devclass implementation
+ */
+
+static devclass_list_t devclasses = TAILQ_HEAD_INITIALIZER(devclasses);
+
+/**
+ * @internal
+ * @brief Find or create a device class
+ *
+ * If a device class with the name @p classname exists, return it,
+ * otherwise if @p create is non-zero create and return a new device
+ * class.
+ *
+ * If @p parentname is non-NULL, the parent of the devclass is set to
+ * the devclass of that name.
+ *
+ * @param classname	the devclass name to find or create
+ * @param parentname	the parent devclass name or @c NULL
+ * @param create	non-zero to create a devclass
+ */
+static devclass_t
+devclass_find_internal(const char *classname, const char *parentname,
+		       int create)
+{
+	devclass_t dc;
+
+	PDEBUG(("looking for %s", classname));
+	if (!classname)
+		return (NULL);
+
+	TAILQ_FOREACH(dc, &devclasses, link) {
+		if (!strcmp(dc->name, classname))
+			break;
+	}
+
+	if (create && !dc) {
+		PDEBUG(("creating %s", classname));
+		dc = malloc(sizeof(struct devclass) + strlen(classname) + 1,
+		    M_BUS, M_NOWAIT | M_ZERO);
+		if (!dc)
+			return (NULL);
+		dc->parent = NULL;
+		dc->name = (char*) (dc + 1);
+		strcpy(dc->name, classname);
+		TAILQ_INIT(&dc->drivers);
+		TAILQ_INSERT_TAIL(&devclasses, dc, link);
+
+		bus_data_generation_update();
+	}
+
+	/*
+	 * If a parent class is specified, then set that as our parent so
+	 * that this devclass will support drivers for the parent class as
+	 * well.  If the parent class has the same name don't do this though
+	 * as it creates a cycle that can trigger an infinite loop in
+	 * device_probe_child() if a device exists for which there is no
+	 * suitable driver.
+	 */
+	if (parentname && dc && !dc->parent &&
+	    strcmp(classname, parentname) != 0) {
+		dc->parent = devclass_find_internal(parentname, NULL, TRUE);
+		dc->parent->flags |= DC_HAS_CHILDREN;
+	}
+
+	return (dc);
+}
+
+/**
+ * @brief Create a device class
+ *
+ * If a device class with the name @p classname exists, return it,
+ * otherwise create and return a new device class.
+ *
+ * @param classname	the devclass name to find or create
+ */
+devclass_t
+devclass_create(const char *classname)
+{
+	return (devclass_find_internal(classname, NULL, TRUE));
+}
+
+/**
+ * @brief Find a device class
+ *
+ * If a device class with the name @p classname exists, return it,
+ * otherwise return @c NULL.
+ *
+ * @param classname	the devclass name to find
+ */
+devclass_t
+devclass_find(const char *classname)
+{
+	return (devclass_find_internal(classname, NULL, FALSE));
+}
+
+/**
+ * @brief Register that a device driver has been added to a devclass
+ *
+ * Register that a device driver has been added to a devclass.  This
+ * is called by devclass_add_driver to accomplish the recursive
+ * notification of all the children classes of dc, as well as dc.
+ * Each layer will have BUS_DRIVER_ADDED() called for all instances of
+ * the devclass.  We do a full search here of the devclass list at
+ * each iteration level to save storing children-lists in the devclass
+ * structure.  If we ever move beyond a few dozen devices doing this,
+ * we may need to reevaluate...
+ *
+ * @param dc		the devclass to edit
+ * @param driver	the driver that was just added
+ */
+static void
+devclass_driver_added(devclass_t dc, driver_t *driver)
+{
+	devclass_t parent;
+	int i;
+
+	/*
+	 * Call BUS_DRIVER_ADDED for any existing busses in this class.
+	 */
+	for (i = 0; i < dc->maxunit; i++)
+		if (dc->devices[i] && device_is_attached(dc->devices[i]))
+			BUS_DRIVER_ADDED(dc->devices[i], driver);
+
+	/*
+	 * Walk through the children classes.  Since we only keep a
+	 * single parent pointer around, we walk the entire list of
+	 * devclasses looking for children.  We set the
+	 * DC_HAS_CHILDREN flag when a child devclass is created on
+	 * the parent, so we only walk the list for those devclasses
+	 * that have children.
+	 */
+	if (!(dc->flags & DC_HAS_CHILDREN))
+		return;
+	parent = dc;
+	TAILQ_FOREACH(dc, &devclasses, link) {
+		if (dc->parent == parent)
+			devclass_driver_added(dc, driver);
+	}
+}
+
+/**
+ * @brief Add a device driver to a device class
+ *
+ * Add a device driver to a devclass. This is normally called
+ * automatically by DRIVER_MODULE(). The BUS_DRIVER_ADDED() method of
+ * all devices in the devclass will be called to allow them to attempt
+ * to re-probe any unmatched children.
+ *
+ * @param dc		the devclass to edit
+ * @param driver	the driver to register
+ */
+static int
+devclass_add_driver(devclass_t dc, driver_t *driver, int pass, devclass_t *dcp)
+{
+	driverlink_t dl;
+	const char *parentname;
+
+	PDEBUG(("%s", DRIVERNAME(driver)));
+
+	/* Don't allow invalid pass values. */
+	if (pass <= BUS_PASS_ROOT)
+		return (EINVAL);
+
+	dl = malloc(sizeof *dl, M_BUS, M_NOWAIT|M_ZERO);
+	if (!dl)
+		return (ENOMEM);
+
+	/*
+	 * Compile the driver's methods. Also increase the reference count
+	 * so that the class doesn't get freed when the last instance
+	 * goes. This means we can safely use static methods and avoids a
+	 * double-free in devclass_delete_driver.
+	 */
+	kobj_class_compile((kobj_class_t) driver);
+
+	/*
+	 * If the driver has any base classes, make the
+	 * devclass inherit from the devclass of the driver's
+	 * first base class. This will allow the system to
+	 * search for drivers in both devclasses for children
+	 * of a device using this driver.
+	 */
+	if (driver->baseclasses)
+		parentname = driver->baseclasses[0]->name;
+	else
+		parentname = NULL;
+	*dcp = devclass_find_internal(driver->name, parentname, TRUE);
+
+	dl->driver = driver;
+	TAILQ_INSERT_TAIL(&dc->drivers, dl, link);
+	driver->refs++;		/* XXX: kobj_mtx */
+	dl->pass = pass;
+	driver_register_pass(dl);
+
+	devclass_driver_added(dc, driver);
+	bus_data_generation_update();
+	return (0);
+}
+
+/**
+ * @brief Delete a device driver from a device class
+ *
+ * Delete a device driver from a devclass. This is normally called
+ * automatically by DRIVER_MODULE().
+ *
+ * If the driver is currently attached to any devices,
+ * devclass_delete_driver() will first attempt to detach from each
+ * device. If one of the detach calls fails, the driver will not be
+ * deleted.
+ *
+ * @param dc		the devclass to edit
+ * @param driver	the driver to unregister
+ */
+static int
+devclass_delete_driver(devclass_t busclass, driver_t *driver)
+{
+	devclass_t dc = devclass_find(driver->name);
+	driverlink_t dl;
+	device_t dev;
+	int i;
+	int error;
+
+	PDEBUG(("%s from devclass %s", driver->name, DEVCLANAME(busclass)));
+
+	if (!dc)
+		return (0);
+
+	/*
+	 * Find the link structure in the bus' list of drivers.
+	 */
+	TAILQ_FOREACH(dl, &busclass->drivers, link) {
+		if (dl->driver == driver)
+			break;
+	}
+
+	if (!dl) {
+		PDEBUG(("%s not found in %s list", driver->name,
+		    busclass->name));
+		return (ENOENT);
+	}
+
+	/*
+	 * Disassociate from any devices.  We iterate through all the
+	 * devices in the devclass of the driver and detach any which are
+	 * using the driver and which have a parent in the devclass which
+	 * we are deleting from.
+	 *
+	 * Note that since a driver can be in multiple devclasses, we
+	 * should not detach devices which are not children of devices in
+	 * the affected devclass.
+	 */
+	for (i = 0; i < dc->maxunit; i++) {
+		if (dc->devices[i]) {
+			dev = dc->devices[i];
+			if (dev->driver == driver && dev->parent &&
+			    dev->parent->devclass == busclass) {
+				if ((error = device_detach(dev)) != 0)
+					return (error);
+				device_set_driver(dev, NULL);
+			}
+		}
+	}
+
+	TAILQ_REMOVE(&busclass->drivers, dl, link);
+	free(dl, M_BUS);
+
+	/* XXX: kobj_mtx */
+	driver->refs--;
+	if (driver->refs == 0)
+		kobj_class_free((kobj_class_t) driver);
+
+	bus_data_generation_update();
+	return (0);
+}
+
+/**
+ * @brief Quiesces a set of device drivers from a device class
+ *
+ * Quiesce a device driver from a devclass. This is normally called
+ * automatically by DRIVER_MODULE().
+ *
+ * If the driver is currently attached to any devices,
+ * devclass_quiesece_driver() will first attempt to quiesce each
+ * device.
+ *
+ * @param dc		the devclass to edit
+ * @param driver	the driver to unregister
+ */
+static int
+devclass_quiesce_driver(devclass_t busclass, driver_t *driver)
+{
+	devclass_t dc = devclass_find(driver->name);
+	driverlink_t dl;
+	device_t dev;
+	int i;
+	int error;
+
+	PDEBUG(("%s from devclass %s", driver->name, DEVCLANAME(busclass)));
+
+	if (!dc)
+		return (0);
+
+	/*
+	 * Find the link structure in the bus' list of drivers.
+	 */
+	TAILQ_FOREACH(dl, &busclass->drivers, link) {
+		if (dl->driver == driver)
+			break;
+	}
+
+	if (!dl) {
+		PDEBUG(("%s not found in %s list", driver->name,
+		    busclass->name));
+		return (ENOENT);
+	}
+
+	/*
+	 * Quiesce all devices.  We iterate through all the devices in
+	 * the devclass of the driver and quiesce any which are using
+	 * the driver and which have a parent in the devclass which we
+	 * are quiescing.
+	 *
+	 * Note that since a driver can be in multiple devclasses, we
+	 * should not quiesce devices which are not children of
+	 * devices in the affected devclass.
+	 */
+	for (i = 0; i < dc->maxunit; i++) {
+		if (dc->devices[i]) {
+			dev = dc->devices[i];
+			if (dev->driver == driver && dev->parent &&
+			    dev->parent->devclass == busclass) {
+				if ((error = device_quiesce(dev)) != 0)
+					return (error);
+			}
+		}
+	}
+
+	return (0);
+}
+
+/**
+ * @internal
+ */
+static driverlink_t
+devclass_find_driver_internal(devclass_t dc, const char *classname)
+{
+	driverlink_t dl;
+
+	PDEBUG(("%s in devclass %s", classname, DEVCLANAME(dc)));
+
+	TAILQ_FOREACH(dl, &dc->drivers, link) {
+		if (!strcmp(dl->driver->name, classname))
+			return (dl);
+	}
+
+	PDEBUG(("not found"));
+	return (NULL);
+}
+
+/**
+ * @brief Return the name of the devclass
+ */
+const char *
+devclass_get_name(devclass_t dc)
+{
+	return (dc->name);
+}
+
+/**
+ * @brief Find a device given a unit number
+ *
+ * @param dc		the devclass to search
+ * @param unit		the unit number to search for
+ * 
+ * @returns		the device with the given unit number or @c
+ *			NULL if there is no such device
+ */
+device_t
+devclass_get_device(devclass_t dc, int unit)
+{
+	if (dc == NULL || unit < 0 || unit >= dc->maxunit)
+		return (NULL);
+	return (dc->devices[unit]);
+}
+
+/**
+ * @brief Find the softc field of a device given a unit number
+ *
+ * @param dc		the devclass to search
+ * @param unit		the unit number to search for
+ * 
+ * @returns		the softc field of the device with the given
+ *			unit number or @c NULL if there is no such
+ *			device
+ */
+void *
+devclass_get_softc(devclass_t dc, int unit)
+{
+	device_t dev;
+
+	dev = devclass_get_device(dc, unit);
+	if (!dev)
+		return (NULL);
+
+	return (device_get_softc(dev));
+}
+
+/**
+ * @brief Get a list of devices in the devclass
+ *
+ * An array containing a list of all the devices in the given devclass
+ * is allocated and returned in @p *devlistp. The number of devices
+ * in the array is returned in @p *devcountp. The caller should free
+ * the array using @c free(p, M_TEMP), even if @p *devcountp is 0.
+ *
+ * @param dc		the devclass to examine
+ * @param devlistp	points at location for array pointer return
+ *			value
+ * @param devcountp	points at location for array size return value
+ *
+ * @retval 0		success
+ * @retval ENOMEM	the array allocation failed
+ */
+int
+devclass_get_devices(devclass_t dc, device_t **devlistp, int *devcountp)
+{
+	int count, i;
+	device_t *list;
+
+	count = devclass_get_count(dc);
+	list = malloc(count * sizeof(device_t), M_TEMP, M_NOWAIT|M_ZERO);
+	if (!list)
+		return (ENOMEM);
+
+	count = 0;
+	for (i = 0; i < dc->maxunit; i++) {
+		if (dc->devices[i]) {
+			list[count] = dc->devices[i];
+			count++;
+		}
+	}
+
+	*devlistp = list;
+	*devcountp = count;
+
+	return (0);
+}
+
+/**
+ * @brief Get a list of drivers in the devclass
+ *
+ * An array containing a list of pointers to all the drivers in the
+ * given devclass is allocated and returned in @p *listp.  The number
+ * of drivers in the array is returned in @p *countp. The caller should
+ * free the array using @c free(p, M_TEMP).
+ *
+ * @param dc		the devclass to examine
+ * @param listp		gives location for array pointer return value
+ * @param countp	gives location for number of array elements
+ *			return value
+ *
+ * @retval 0		success
+ * @retval ENOMEM	the array allocation failed
+ */
+int
+devclass_get_drivers(devclass_t dc, driver_t ***listp, int *countp)
+{
+	driverlink_t dl;
+	driver_t **list;
+	int count;
+
+	count = 0;
+	TAILQ_FOREACH(dl, &dc->drivers, link)
+		count++;
+	list = malloc(count * sizeof(driver_t *), M_TEMP, M_NOWAIT);
+	if (list == NULL)
+		return (ENOMEM);
+
+	count = 0;
+	TAILQ_FOREACH(dl, &dc->drivers, link) {
+		list[count] = dl->driver;
+		count++;
+	}
+	*listp = list;
+	*countp = count;
+
+	return (0);
+}
+
+/**
+ * @brief Get the number of devices in a devclass
+ *
+ * @param dc		the devclass to examine
+ */
+int
+devclass_get_count(devclass_t dc)
+{
+	int count, i;
+
+	count = 0;
+	for (i = 0; i < dc->maxunit; i++)
+		if (dc->devices[i])
+			count++;
+	return (count);
+}
+
+/**
+ * @brief Get the maximum unit number used in a devclass
+ *
+ * Note that this is one greater than the highest currently-allocated
+ * unit.  If a null devclass_t is passed in, -1 is returned to indicate
+ * that not even the devclass has been allocated yet.
+ *
+ * @param dc		the devclass to examine
+ */
+int
+devclass_get_maxunit(devclass_t dc)
+{
+	if (dc == NULL)
+		return (-1);
+	return (dc->maxunit);
+}
+
+/**
+ * @brief Find a free unit number in a devclass
+ *
+ * This function searches for the first unused unit number greater
+ * that or equal to @p unit.
+ *
+ * @param dc		the devclass to examine
+ * @param unit		the first unit number to check
+ */
+int
+devclass_find_free_unit(devclass_t dc, int unit)
+{
+	if (dc == NULL)
+		return (unit);
+	while (unit < dc->maxunit && dc->devices[unit] != NULL)
+		unit++;
+	return (unit);
+}
+
+/**
+ * @brief Set the parent of a devclass
+ *
+ * The parent class is normally initialised automatically by
+ * DRIVER_MODULE().
+ *
+ * @param dc		the devclass to edit
+ * @param pdc		the new parent devclass
+ */
+void
+devclass_set_parent(devclass_t dc, devclass_t pdc)
+{
+	dc->parent = pdc;
+}
+
+/**
+ * @brief Get the parent of a devclass
+ *
+ * @param dc		the devclass to examine
+ */
+devclass_t
+devclass_get_parent(devclass_t dc)
+{
+	return (dc->parent);
+}
+
+struct sysctl_ctx_list *
+devclass_get_sysctl_ctx(devclass_t dc)
+{
+#ifndef __rtems__
+	return (&dc->sysctl_ctx);
+#else /* __rtems__ */
+	return (NULL);
+#endif /* __rtems__ */
+}
+
+struct sysctl_oid *
+devclass_get_sysctl_tree(devclass_t dc)
+{
+#ifndef __rtems__
+	return (dc->sysctl_tree);
+#else /* __rtems__ */
+	return (NULL);
+#endif /* __rtems__ */
+}
+
+/**
+ * @internal
+ * @brief Allocate a unit number
+ *
+ * On entry, @p *unitp is the desired unit number (or @c -1 if any
+ * will do). The allocated unit number is returned in @p *unitp.
+
+ * @param dc		the devclass to allocate from
+ * @param unitp		points at the location for the allocated unit
+ *			number
+ *
+ * @retval 0		success
+ * @retval EEXIST	the requested unit number is already allocated
+ * @retval ENOMEM	memory allocation failure
+ */
+static int
+devclass_alloc_unit(devclass_t dc, device_t dev, int *unitp)
+{
+	const char *s;
+	int unit = *unitp;
+
+	PDEBUG(("unit %d in devclass %s", unit, DEVCLANAME(dc)));
+
+	/* Ask the parent bus if it wants to wire this device. */
+	if (unit == -1)
+		BUS_HINT_DEVICE_UNIT(device_get_parent(dev), dev, dc->name,
+		    &unit);
+
+	/* If we were given a wired unit number, check for existing device */
+	/* XXX imp XXX */
+	if (unit != -1) {
+		if (unit >= 0 && unit < dc->maxunit &&
+		    dc->devices[unit] != NULL) {
+			if (bootverbose)
+				printf("%s: %s%d already exists; skipping it\n",
+				    dc->name, dc->name, *unitp);
+			return (EEXIST);
+		}
+	} else {
+		/* Unwired device, find the next available slot for it */
+		unit = 0;
+		for (unit = 0;; unit++) {
+#ifndef __rtems__
+			/* If there is an "at" hint for a unit then skip it. */
+			if (resource_string_value(dc->name, unit, "at", &s) ==
+			    0)
+				continue;
+#endif /* __rtems__ */
+
+			/* If this device slot is already in use, skip it. */
+			if (unit < dc->maxunit && dc->devices[unit] != NULL)
+				continue;
+
+			break;
+		}
+	}
+
+	/*
+	 * We've selected a unit beyond the length of the table, so let's
+	 * extend the table to make room for all units up to and including
+	 * this one.
+	 */
+	if (unit >= dc->maxunit) {
+		device_t *newlist, *oldlist;
+		int newsize;
+
+		oldlist = dc->devices;
+		newsize = roundup((unit + 1), MINALLOCSIZE / sizeof(device_t));
+		newlist = malloc(sizeof(device_t) * newsize, M_BUS, M_NOWAIT);
+		if (!newlist)
+			return (ENOMEM);
+		if (oldlist != NULL)
+			bcopy(oldlist, newlist, sizeof(device_t) * dc->maxunit);
+		bzero(newlist + dc->maxunit,
+		    sizeof(device_t) * (newsize - dc->maxunit));
+		dc->devices = newlist;
+		dc->maxunit = newsize;
+		if (oldlist != NULL)
+			free(oldlist, M_BUS);
+	}
+	PDEBUG(("now: unit %d in devclass %s", unit, DEVCLANAME(dc)));
+
+	*unitp = unit;
+	return (0);
+}
+
+/**
+ * @internal
+ * @brief Add a device to a devclass
+ *
+ * A unit number is allocated for the device (using the device's
+ * preferred unit number if any) and the device is registered in the
+ * devclass. This allows the device to be looked up by its unit
+ * number, e.g. by decoding a dev_t minor number.
+ *
+ * @param dc		the devclass to add to
+ * @param dev		the device to add
+ *
+ * @retval 0		success
+ * @retval EEXIST	the requested unit number is already allocated
+ * @retval ENOMEM	memory allocation failure
+ */
+static int
+devclass_add_device(devclass_t dc, device_t dev)
+{
+	int buflen, error;
+
+	PDEBUG(("%s in devclass %s", DEVICENAME(dev), DEVCLANAME(dc)));
+
+	buflen = snprintf(NULL, 0, "%s%d$", dc->name, INT_MAX);
+	if (buflen < 0)
+		return (ENOMEM);
+	dev->nameunit = malloc(buflen, M_BUS, M_NOWAIT|M_ZERO);
+	if (!dev->nameunit)
+		return (ENOMEM);
+
+	if ((error = devclass_alloc_unit(dc, dev, &dev->unit)) != 0) {
+		free(dev->nameunit, M_BUS);
+		dev->nameunit = NULL;
+		return (error);
+	}
+	dc->devices[dev->unit] = dev;
+	dev->devclass = dc;
+	snprintf(dev->nameunit, buflen, "%s%d", dc->name, dev->unit);
+
+	return (0);
+}
+
+/**
+ * @internal
+ * @brief Delete a device from a devclass
+ *
+ * The device is removed from the devclass's device list and its unit
+ * number is freed.
+
+ * @param dc		the devclass to delete from
+ * @param dev		the device to delete
+ *
+ * @retval 0		success
+ */
+static int
+devclass_delete_device(devclass_t dc, device_t dev)
+{
+	if (!dc || !dev)
+		return (0);
+
+	PDEBUG(("%s in devclass %s", DEVICENAME(dev), DEVCLANAME(dc)));
+
+	if (dev->devclass != dc || dc->devices[dev->unit] != dev)
+		panic("devclass_delete_device: inconsistent device class");
+	dc->devices[dev->unit] = NULL;
+	if (dev->flags & DF_WILDCARD)
+		dev->unit = -1;
+	dev->devclass = NULL;
+	free(dev->nameunit, M_BUS);
+	dev->nameunit = NULL;
+
+	return (0);
+}
+
+/**
+ * @internal
+ * @brief Make a new device and add it as a child of @p parent
+ *
+ * @param parent	the parent of the new device
+ * @param name		the devclass name of the new device or @c NULL
+ *			to leave the devclass unspecified
+ * @parem unit		the unit number of the new device of @c -1 to
+ *			leave the unit number unspecified
+ *
+ * @returns the new device
+ */
+static device_t
+make_device(device_t parent, const char *name, int unit)
+{
+	device_t dev;
+	devclass_t dc;
+
+	PDEBUG(("%s at %s as unit %d", name, DEVICENAME(parent), unit));
+
+	if (name) {
+		dc = devclass_find_internal(name, NULL, TRUE);
+		if (!dc) {
+			printf("make_device: can't find device class %s\n",
+			    name);
+			return (NULL);
+		}
+	} else {
+		dc = NULL;
+	}
+
+	dev = malloc(sizeof(struct device), M_BUS, M_NOWAIT|M_ZERO);
+	if (!dev)
+		return (NULL);
+
+	dev->parent = parent;
+	TAILQ_INIT(&dev->children);
+	kobj_init((kobj_t) dev, &null_class);
+	dev->driver = NULL;
+	dev->devclass = NULL;
+	dev->unit = unit;
+	dev->nameunit = NULL;
+	dev->desc = NULL;
+	dev->busy = 0;
+	dev->devflags = 0;
+	dev->flags = DF_ENABLED;
+	dev->order = 0;
+	if (unit == -1)
+		dev->flags |= DF_WILDCARD;
+	if (name) {
+		dev->flags |= DF_FIXEDCLASS;
+		if (devclass_add_device(dc, dev)) {
+			kobj_delete((kobj_t) dev, M_BUS);
+			return (NULL);
+		}
+	}
+	dev->ivars = NULL;
+	dev->softc = NULL;
+
+	dev->state = DS_NOTPRESENT;
+
+	TAILQ_INSERT_TAIL(&bus_data_devices, dev, devlink);
+	bus_data_generation_update();
+
+	return (dev);
+}
+
+/**
+ * @internal
+ * @brief Print a description of a device.
+ */
+static int
+device_print_child(device_t dev, device_t child)
+{
+	int retval = 0;
+
+	if (device_is_alive(child))
+		retval += BUS_PRINT_CHILD(dev, child);
+	else
+		retval += device_printf(child, " not found\n");
+
+	return (retval);
+}
+
+/**
+ * @brief Create a new device
+ *
+ * This creates a new device and adds it as a child of an existing
+ * parent device. The new device will be added after the last existing
+ * child with order zero.
+ * 
+ * @param dev		the device which will be the parent of the
+ *			new child device
+ * @param name		devclass name for new device or @c NULL if not
+ *			specified
+ * @param unit		unit number for new device or @c -1 if not
+ *			specified
+ * 
+ * @returns		the new device
+ */
+device_t
+device_add_child(device_t dev, const char *name, int unit)
+{
+	return (device_add_child_ordered(dev, 0, name, unit));
+}
+
+/**
+ * @brief Create a new device
+ *
+ * This creates a new device and adds it as a child of an existing
+ * parent device. The new device will be added after the last existing
+ * child with the same order.
+ * 
+ * @param dev		the device which will be the parent of the
+ *			new child device
+ * @param order		a value which is used to partially sort the
+ *			children of @p dev - devices created using
+ *			lower values of @p order appear first in @p
+ *			dev's list of children
+ * @param name		devclass name for new device or @c NULL if not
+ *			specified
+ * @param unit		unit number for new device or @c -1 if not
+ *			specified
+ * 
+ * @returns		the new device
+ */
+device_t
+device_add_child_ordered(device_t dev, u_int order, const char *name, int unit)
+{
+	device_t child;
+	device_t place;
+
+	PDEBUG(("%s at %s with order %u as unit %d",
+	    name, DEVICENAME(dev), order, unit));
+
+	child = make_device(dev, name, unit);
+	if (child == NULL)
+		return (child);
+	child->order = order;
+
+	TAILQ_FOREACH(place, &dev->children, link) {
+		if (place->order > order)
+			break;
+	}
+
+	if (place) {
+		/*
+		 * The device 'place' is the first device whose order is
+		 * greater than the new child.
+		 */
+		TAILQ_INSERT_BEFORE(place, child, link);
+	} else {
+		/*
+		 * The new child's order is greater or equal to the order of
+		 * any existing device. Add the child to the tail of the list.
+		 */
+		TAILQ_INSERT_TAIL(&dev->children, child, link);
+	}
+
+	bus_data_generation_update();
+	return (child);
+}
+
+/**
+ * @brief Delete a device
+ *
+ * This function deletes a device along with all of its children. If
+ * the device currently has a driver attached to it, the device is
+ * detached first using device_detach().
+ * 
+ * @param dev		the parent device
+ * @param child		the device to delete
+ *
+ * @retval 0		success
+ * @retval non-zero	a unit error code describing the error
+ */
+int
+device_delete_child(device_t dev, device_t child)
+{
+	int error;
+	device_t grandchild;
+
+	PDEBUG(("%s from %s", DEVICENAME(child), DEVICENAME(dev)));
+
+	/* remove children first */
+	while ( (grandchild = TAILQ_FIRST(&child->children)) ) {
+		error = device_delete_child(child, grandchild);
+		if (error)
+			return (error);
+	}
+
+	if ((error = device_detach(child)) != 0)
+		return (error);
+	if (child->devclass)
+		devclass_delete_device(child->devclass, child);
+	TAILQ_REMOVE(&dev->children, child, link);
+	TAILQ_REMOVE(&bus_data_devices, child, devlink);
+	kobj_delete((kobj_t) child, M_BUS);
+
+	bus_data_generation_update();
+	return (0);
+}
+
+/**
+ * @brief Find a device given a unit number
+ *
+ * This is similar to devclass_get_devices() but only searches for
+ * devices which have @p dev as a parent.
+ *
+ * @param dev		the parent device to search
+ * @param unit		the unit number to search for.  If the unit is -1,
+ *			return the first child of @p dev which has name
+ *			@p classname (that is, the one with the lowest unit.)
+ *
+ * @returns		the device with the given unit number or @c
+ *			NULL if there is no such device
+ */
+device_t
+device_find_child(device_t dev, const char *classname, int unit)
+{
+	devclass_t dc;
+	device_t child;
+
+	dc = devclass_find(classname);
+	if (!dc)
+		return (NULL);
+
+	if (unit != -1) {
+		child = devclass_get_device(dc, unit);
+		if (child && child->parent == dev)
+			return (child);
+	} else {
+		for (unit = 0; unit < devclass_get_maxunit(dc); unit++) {
+			child = devclass_get_device(dc, unit);
+			if (child && child->parent == dev)
+				return (child);
+		}
+	}
+	return (NULL);
+}
+
+/**
+ * @internal
+ */
+static driverlink_t
+first_matching_driver(devclass_t dc, device_t dev)
+{
+	if (dev->devclass)
+		return (devclass_find_driver_internal(dc, dev->devclass->name));
+	return (TAILQ_FIRST(&dc->drivers));
+}
+
+/**
+ * @internal
+ */
+static driverlink_t
+next_matching_driver(devclass_t dc, device_t dev, driverlink_t last)
+{
+	if (dev->devclass) {
+		driverlink_t dl;
+		for (dl = TAILQ_NEXT(last, link); dl; dl = TAILQ_NEXT(dl, link))
+			if (!strcmp(dev->devclass->name, dl->driver->name))
+				return (dl);
+		return (NULL);
+	}
+	return (TAILQ_NEXT(last, link));
+}
+
+/**
+ * @internal
+ */
+int
+device_probe_child(device_t dev, device_t child)
+{
+	devclass_t dc;
+	driverlink_t best = NULL;
+	driverlink_t dl;
+	int result, pri = 0;
+	int hasclass = (child->devclass != NULL);
+
+	GIANT_REQUIRED;
+
+	dc = dev->devclass;
+	if (!dc)
+		panic("device_probe_child: parent device has no devclass");
+
+	/*
+	 * If the state is already probed, then return.  However, don't
+	 * return if we can rebid this object.
+	 */
+	if (child->state == DS_ALIVE && (child->flags & DF_REBID) == 0)
+		return (0);
+
+	for (; dc; dc = dc->parent) {
+		for (dl = first_matching_driver(dc, child);
+		     dl;
+		     dl = next_matching_driver(dc, child, dl)) {
+
+			/* If this driver's pass is too high, then ignore it. */
+			if (dl->pass > bus_current_pass)
+				continue;
+
+			PDEBUG(("Trying %s", DRIVERNAME(dl->driver)));
+			device_set_driver(child, dl->driver);
+			if (!hasclass) {
+				if (device_set_devclass(child, dl->driver->name)) {
+					printf("driver bug: Unable to set devclass (devname: %s)\n",
+					    (child ? device_get_name(child) :
+						"no device"));
+					device_set_driver(child, NULL);
+					continue;
+				}
+			}
+
+#ifndef __rtems__
+			/* Fetch any flags for the device before probing. */
+			resource_int_value(dl->driver->name, child->unit,
+			    "flags", &child->devflags);
+#endif /* __rtems__ */
+
+			result = DEVICE_PROBE(child);
+
+			/* Reset flags and devclass before the next probe. */
+			child->devflags = 0;
+			if (!hasclass)
+				device_set_devclass(child, NULL);
+
+			/*
+			 * If the driver returns SUCCESS, there can be
+			 * no higher match for this device.
+			 */
+			if (result == 0) {
+				best = dl;
+				pri = 0;
+				break;
+			}
+
+			/*
+			 * The driver returned an error so it
+			 * certainly doesn't match.
+			 */
+			if (result > 0) {
+				device_set_driver(child, NULL);
+				continue;
+			}
+
+			/*
+			 * A priority lower than SUCCESS, remember the
+			 * best matching driver. Initialise the value
+			 * of pri for the first match.
+			 */
+			if (best == NULL || result > pri) {
+				/*
+				 * Probes that return BUS_PROBE_NOWILDCARD
+				 * or lower only match when they are set
+				 * in stone by the parent bus.
+				 */
+				if (result <= BUS_PROBE_NOWILDCARD &&
+				    child->flags & DF_WILDCARD)
+					continue;
+				best = dl;
+				pri = result;
+				continue;
+			}
+		}
+		/*
+		 * If we have an unambiguous match in this devclass,
+		 * don't look in the parent.
+		 */
+		if (best && pri == 0)
+			break;
+	}
+
+	/*
+	 * If we found a driver, change state and initialise the devclass.
+	 */
+	/* XXX What happens if we rebid and got no best? */
+	if (best) {
+		/*
+		 * If this device was atached, and we were asked to
+		 * rescan, and it is a different driver, then we have
+		 * to detach the old driver and reattach this new one.
+		 * Note, we don't have to check for DF_REBID here
+		 * because if the state is > DS_ALIVE, we know it must
+		 * be.
+		 *
+		 * This assumes that all DF_REBID drivers can have
+		 * their probe routine called at any time and that
+		 * they are idempotent as well as completely benign in
+		 * normal operations.
+		 *
+		 * We also have to make sure that the detach
+		 * succeeded, otherwise we fail the operation (or
+		 * maybe it should just fail silently?  I'm torn).
+		 */
+		if (child->state > DS_ALIVE && best->driver != child->driver)
+			if ((result = device_detach(dev)) != 0)
+				return (result);
+
+		/* Set the winning driver, devclass, and flags. */
+		if (!child->devclass) {
+			result = device_set_devclass(child, best->driver->name);
+			if (result != 0)
+				return (result);
+		}
+		device_set_driver(child, best->driver);
+#ifndef __rtems__
+		resource_int_value(best->driver->name, child->unit,
+		    "flags", &child->devflags);
+#endif /* __rtems__ */
+
+		if (pri < 0) {
+			/*
+			 * A bit bogus. Call the probe method again to make
+			 * sure that we have the right description.
+			 */
+			DEVICE_PROBE(child);
+#if 0
+			child->flags |= DF_REBID;
+#endif
+		} else
+			child->flags &= ~DF_REBID;
+		child->state = DS_ALIVE;
+
+		bus_data_generation_update();
+		return (0);
+	}
+
+	return (ENXIO);
+}
+
+/**
+ * @brief Return the parent of a device
+ */
+device_t
+device_get_parent(device_t dev)
+{
+	return (dev->parent);
+}
+
+/**
+ * @brief Get a list of children of a device
+ *
+ * An array containing a list of all the children of the given device
+ * is allocated and returned in @p *devlistp. The number of devices
+ * in the array is returned in @p *devcountp. The caller should free
+ * the array using @c free(p, M_TEMP).
+ *
+ * @param dev		the device to examine
+ * @param devlistp	points at location for array pointer return
+ *			value
+ * @param devcountp	points at location for array size return value
+ *
+ * @retval 0		success
+ * @retval ENOMEM	the array allocation failed
+ */
+int
+device_get_children(device_t dev, device_t **devlistp, int *devcountp)
+{
+	int count;
+	device_t child;
+	device_t *list;
+
+	count = 0;
+	TAILQ_FOREACH(child, &dev->children, link) {
+		count++;
+	}
+
+#ifdef __rtems__
+	/* malloc(0) may return NULL */
+	if (count != 0) {
+#endif /* __rtems__ */
+	list = malloc(count * sizeof(device_t), M_TEMP, M_NOWAIT|M_ZERO);
+	if (!list)
+		return (ENOMEM);
+
+	count = 0;
+	TAILQ_FOREACH(child, &dev->children, link) {
+		list[count] = child;
+		count++;
+	}
+#ifdef __rtems__
+	} else {
+		list = NULL;
+	}
+#endif /* __rtems__ */
+
+	*devlistp = list;
+	*devcountp = count;
+
+	return (0);
+}
+
+/**
+ * @brief Return the current driver for the device or @c NULL if there
+ * is no driver currently attached
+ */
+driver_t *
+device_get_driver(device_t dev)
+{
+	return (dev->driver);
+}
+
+/**
+ * @brief Return the current devclass for the device or @c NULL if
+ * there is none.
+ */
+devclass_t
+device_get_devclass(device_t dev)
+{
+	return (dev->devclass);
+}
+
+/**
+ * @brief Return the name of the device's devclass or @c NULL if there
+ * is none.
+ */
+const char *
+device_get_name(device_t dev)
+{
+	if (dev != NULL && dev->devclass)
+		return (devclass_get_name(dev->devclass));
+	return (NULL);
+}
+
+/**
+ * @brief Return a string containing the device's devclass name
+ * followed by an ascii representation of the device's unit number
+ * (e.g. @c "foo2").
+ */
+const char *
+device_get_nameunit(device_t dev)
+{
+	return (dev->nameunit);
+}
+
+/**
+ * @brief Return the device's unit number.
+ */
+int
+device_get_unit(device_t dev)
+{
+	return (dev->unit);
+}
+
+/**
+ * @brief Return the device's description string
+ */
+const char *
+device_get_desc(device_t dev)
+{
+	return (dev->desc);
+}
+
+/**
+ * @brief Return the device's flags
+ */
+u_int32_t
+device_get_flags(device_t dev)
+{
+	return (dev->devflags);
+}
+
+struct sysctl_ctx_list *
+device_get_sysctl_ctx(device_t dev)
+{
+#ifndef __rtems__
+	return (&dev->sysctl_ctx);
+#else /* __rtems__ */
+	return (NULL);
+#endif /* __rtems__ */
+}
+
+struct sysctl_oid *
+device_get_sysctl_tree(device_t dev)
+{
+#ifndef __rtems__
+	return (dev->sysctl_tree);
+#else /* __rtems__ */
+	return (NULL);
+#endif /* __rtems__ */
+}
+
+/**
+ * @brief Print the name of the device followed by a colon and a space
+ *
+ * @returns the number of characters printed
+ */
+int
+device_print_prettyname(device_t dev)
+{
+	const char *name = device_get_name(dev);
+
+	if (name == NULL)
+		return (printf("unknown: "));
+	return (printf("%s%d: ", name, device_get_unit(dev)));
+}
+
+/**
+ * @brief Print the name of the device followed by a colon, a space
+ * and the result of calling vprintf() with the value of @p fmt and
+ * the following arguments.
+ *
+ * @returns the number of characters printed
+ */
+int
+device_printf(device_t dev, const char * fmt, ...)
+{
+	va_list ap;
+	int retval;
+
+	retval = device_print_prettyname(dev);
+	va_start(ap, fmt);
+	retval += vprintf(fmt, ap);
+	va_end(ap);
+	return (retval);
+}
+
+/**
+ * @internal
+ */
+static void
+device_set_desc_internal(device_t dev, const char* desc, int copy)
+{
+	if (dev->desc && (dev->flags & DF_DESCMALLOCED)) {
+		free(dev->desc, M_BUS);
+		dev->flags &= ~DF_DESCMALLOCED;
+		dev->desc = NULL;
+	}
+
+	if (copy && desc) {
+		dev->desc = malloc(strlen(desc) + 1, M_BUS, M_NOWAIT);
+		if (dev->desc) {
+			strcpy(dev->desc, desc);
+			dev->flags |= DF_DESCMALLOCED;
+		}
+	} else {
+		/* Avoid a -Wcast-qual warning */
+		dev->desc = (char *)(uintptr_t) desc;
+	}
+
+	bus_data_generation_update();
+}
+
+/**
+ * @brief Set the device's description
+ *
+ * The value of @c desc should be a string constant that will not
+ * change (at least until the description is changed in a subsequent
+ * call to device_set_desc() or device_set_desc_copy()).
+ */
+void
+device_set_desc(device_t dev, const char* desc)
+{
+	device_set_desc_internal(dev, desc, FALSE);
+}
+
+/**
+ * @brief Set the device's description
+ *
+ * The string pointed to by @c desc is copied. Use this function if
+ * the device description is generated, (e.g. with sprintf()).
+ */
+void
+device_set_desc_copy(device_t dev, const char* desc)
+{
+	device_set_desc_internal(dev, desc, TRUE);
+}
+
+/**
+ * @brief Set the device's flags
+ */
+void
+device_set_flags(device_t dev, u_int32_t flags)
+{
+	dev->devflags = flags;
+}
+
+/**
+ * @brief Return the device's softc field
+ *
+ * The softc is allocated and zeroed when a driver is attached, based
+ * on the size field of the driver.
+ */
+void *
+device_get_softc(device_t dev)
+{
+	return (dev->softc);
+}
+
+/**
+ * @brief Set the device's softc field
+ *
+ * Most drivers do not need to use this since the softc is allocated
+ * automatically when the driver is attached.
+ */
+void
+device_set_softc(device_t dev, void *softc)
+{
+	if (dev->softc && !(dev->flags & DF_EXTERNALSOFTC))
+		free(dev->softc, M_BUS_SC);
+	dev->softc = softc;
+	if (dev->softc)
+		dev->flags |= DF_EXTERNALSOFTC;
+	else
+		dev->flags &= ~DF_EXTERNALSOFTC;
+}
+
+/**
+ * @brief Get the device's ivars field
+ *
+ * The ivars field is used by the parent device to store per-device
+ * state (e.g. the physical location of the device or a list of
+ * resources).
+ */
+void *
+device_get_ivars(device_t dev)
+{
+
+	KASSERT(dev != NULL, ("device_get_ivars(NULL, ...)"));
+	return (dev->ivars);
+}
+
+/**
+ * @brief Set the device's ivars field
+ */
+void
+device_set_ivars(device_t dev, void * ivars)
+{
+
+	KASSERT(dev != NULL, ("device_set_ivars(NULL, ...)"));
+	dev->ivars = ivars;
+}
+
+/**
+ * @brief Return the device's state
+ */
+device_state_t
+device_get_state(device_t dev)
+{
+	return (dev->state);
+}
+
+/**
+ * @brief Set the DF_ENABLED flag for the device
+ */
+void
+device_enable(device_t dev)
+{
+	dev->flags |= DF_ENABLED;
+}
+
+/**
+ * @brief Clear the DF_ENABLED flag for the device
+ */
+void
+device_disable(device_t dev)
+{
+	dev->flags &= ~DF_ENABLED;
+}
+
+/**
+ * @brief Increment the busy counter for the device
+ */
+void
+device_busy(device_t dev)
+{
+	if (dev->state < DS_ATTACHED)
+		panic("device_busy: called for unattached device");
+	if (dev->busy == 0 && dev->parent)
+		device_busy(dev->parent);
+	dev->busy++;
+	dev->state = DS_BUSY;
+}
+
+/**
+ * @brief Decrement the busy counter for the device
+ */
+void
+device_unbusy(device_t dev)
+{
+	if (dev->state != DS_BUSY)
+		panic("device_unbusy: called for non-busy device %s",
+		    device_get_nameunit(dev));
+	dev->busy--;
+	if (dev->busy == 0) {
+		if (dev->parent)
+			device_unbusy(dev->parent);
+		dev->state = DS_ATTACHED;
+	}
+}
+
+/**
+ * @brief Set the DF_QUIET flag for the device
+ */
+void
+device_quiet(device_t dev)
+{
+	dev->flags |= DF_QUIET;
+}
+
+/**
+ * @brief Clear the DF_QUIET flag for the device
+ */
+void
+device_verbose(device_t dev)
+{
+	dev->flags &= ~DF_QUIET;
+}
+
+/**
+ * @brief Return non-zero if the DF_QUIET flag is set on the device
+ */
+int
+device_is_quiet(device_t dev)
+{
+	return ((dev->flags & DF_QUIET) != 0);
+}
+
+/**
+ * @brief Return non-zero if the DF_ENABLED flag is set on the device
+ */
+int
+device_is_enabled(device_t dev)
+{
+	return ((dev->flags & DF_ENABLED) != 0);
+}
+
+/**
+ * @brief Return non-zero if the device was successfully probed
+ */
+int
+device_is_alive(device_t dev)
+{
+	return (dev->state >= DS_ALIVE);
+}
+
+/**
+ * @brief Return non-zero if the device currently has a driver
+ * attached to it
+ */
+int
+device_is_attached(device_t dev)
+{
+	return (dev->state >= DS_ATTACHED);
+}
+
+/**
+ * @brief Set the devclass of a device
+ * @see devclass_add_device().
+ */
+int
+device_set_devclass(device_t dev, const char *classname)
+{
+	devclass_t dc;
+	int error;
+
+	if (!classname) {
+		if (dev->devclass)
+			devclass_delete_device(dev->devclass, dev);
+		return (0);
+	}
+
+	if (dev->devclass) {
+		printf("device_set_devclass: device class already set\n");
+		return (EINVAL);
+	}
+
+	dc = devclass_find_internal(classname, NULL, TRUE);
+	if (!dc)
+		return (ENOMEM);
+
+	error = devclass_add_device(dc, dev);
+
+	bus_data_generation_update();
+	return (error);
+}
+
+/**
+ * @brief Set the driver of a device
+ *
+ * @retval 0		success
+ * @retval EBUSY	the device already has a driver attached
+ * @retval ENOMEM	a memory allocation failure occurred
+ */
+int
+device_set_driver(device_t dev, driver_t *driver)
+{
+	if (dev->state >= DS_ATTACHED)
+		return (EBUSY);
+
+	if (dev->driver == driver)
+		return (0);
+
+	if (dev->softc && !(dev->flags & DF_EXTERNALSOFTC)) {
+		free(dev->softc, M_BUS_SC);
+		dev->softc = NULL;
+	}
+	kobj_delete((kobj_t) dev, NULL);
+	dev->driver = driver;
+	if (driver) {
+		kobj_init((kobj_t) dev, (kobj_class_t) driver);
+		if (!(dev->flags & DF_EXTERNALSOFTC) && driver->size > 0) {
+			dev->softc = malloc(driver->size, M_BUS_SC,
+			    M_NOWAIT | M_ZERO);
+			if (!dev->softc) {
+				kobj_delete((kobj_t) dev, NULL);
+				kobj_init((kobj_t) dev, &null_class);
+				dev->driver = NULL;
+				return (ENOMEM);
+			}
+		}
+	} else {
+		kobj_init((kobj_t) dev, &null_class);
+	}
+
+	bus_data_generation_update();
+	return (0);
+}
+
+/**
+ * @brief Probe a device, and return this status.
+ *
+ * This function is the core of the device autoconfiguration
+ * system. Its purpose is to select a suitable driver for a device and
+ * then call that driver to initialise the hardware appropriately. The
+ * driver is selected by calling the DEVICE_PROBE() method of a set of
+ * candidate drivers and then choosing the driver which returned the
+ * best value. This driver is then attached to the device using
+ * device_attach().
+ *
+ * The set of suitable drivers is taken from the list of drivers in
+ * the parent device's devclass. If the device was originally created
+ * with a specific class name (see device_add_child()), only drivers
+ * with that name are probed, otherwise all drivers in the devclass
+ * are probed. If no drivers return successful probe values in the
+ * parent devclass, the search continues in the parent of that
+ * devclass (see devclass_get_parent()) if any.
+ *
+ * @param dev		the device to initialise
+ *
+ * @retval 0		success
+ * @retval ENXIO	no driver was found
+ * @retval ENOMEM	memory allocation failure
+ * @retval non-zero	some other unix error code
+ * @retval -1		Device already attached
+ */
+int
+device_probe(device_t dev)
+{
+	int error;
+
+	GIANT_REQUIRED;
+
+	if (dev->state >= DS_ALIVE && (dev->flags & DF_REBID) == 0)
+		return (-1);
+
+	if (!(dev->flags & DF_ENABLED)) {
+		if (bootverbose && device_get_name(dev) != NULL) {
+			device_print_prettyname(dev);
+			printf("not probed (disabled)\n");
+		}
+		return (-1);
+	}
+	if ((error = device_probe_child(dev->parent, dev)) != 0) {		
+		if (bus_current_pass == BUS_PASS_DEFAULT &&
+		    !(dev->flags & DF_DONENOMATCH)) {
+			BUS_PROBE_NOMATCH(dev->parent, dev);
+			devnomatch(dev);
+			dev->flags |= DF_DONENOMATCH;
+		}
+		return (error);
+	}
+	return (0);
+}
+
+/**
+ * @brief Probe a device and attach a driver if possible
+ *
+ * calls device_probe() and attaches if that was successful.
+ */
+int
+device_probe_and_attach(device_t dev)
+{
+	int error;
+
+	GIANT_REQUIRED;
+
+	error = device_probe(dev);
+	if (error == -1)
+		return (0);
+	else if (error != 0)
+		return (error);
+	return (device_attach(dev));
+}
+
+/**
+ * @brief Attach a device driver to a device
+ *
+ * This function is a wrapper around the DEVICE_ATTACH() driver
+ * method. In addition to calling DEVICE_ATTACH(), it initialises the
+ * device's sysctl tree, optionally prints a description of the device
+ * and queues a notification event for user-based device management
+ * services.
+ *
+ * Normally this function is only called internally from
+ * device_probe_and_attach().
+ *
+ * @param dev		the device to initialise
+ *
+ * @retval 0		success
+ * @retval ENXIO	no driver was found
+ * @retval ENOMEM	memory allocation failure
+ * @retval non-zero	some other unix error code
+ */
+int
+device_attach(device_t dev)
+{
+	int error;
+
+	device_sysctl_init(dev);
+	if (!device_is_quiet(dev))
+		device_print_child(dev->parent, dev);
+	if ((error = DEVICE_ATTACH(dev)) != 0) {
+		printf("device_attach: %s%d attach returned %d\n",
+		    dev->driver->name, dev->unit, error);
+		/* Unset the class; set in device_probe_child */
+		if (dev->devclass == NULL)
+			device_set_devclass(dev, NULL);
+		device_set_driver(dev, NULL);
+		device_sysctl_fini(dev);
+		dev->state = DS_NOTPRESENT;
+		return (error);
+	}
+	device_sysctl_update(dev);
+	dev->state = DS_ATTACHED;
+	devadded(dev);
+	return (0);
+}
+
+/**
+ * @brief Detach a driver from a device
+ *
+ * This function is a wrapper around the DEVICE_DETACH() driver
+ * method. If the call to DEVICE_DETACH() succeeds, it calls
+ * BUS_CHILD_DETACHED() for the parent of @p dev, queues a
+ * notification event for user-based device management services and
+ * cleans up the device's sysctl tree.
+ *
+ * @param dev		the device to un-initialise
+ *
+ * @retval 0		success
+ * @retval ENXIO	no driver was found
+ * @retval ENOMEM	memory allocation failure
+ * @retval non-zero	some other unix error code
+ */
+int
+device_detach(device_t dev)
+{
+	int error;
+
+	GIANT_REQUIRED;
+
+	PDEBUG(("%s", DEVICENAME(dev)));
+	if (dev->state == DS_BUSY)
+		return (EBUSY);
+	if (dev->state != DS_ATTACHED)
+		return (0);
+
+	if ((error = DEVICE_DETACH(dev)) != 0)
+		return (error);
+	devremoved(dev);
+	if (!device_is_quiet(dev))
+		device_printf(dev, "detached\n");
+	if (dev->parent)
+		BUS_CHILD_DETACHED(dev->parent, dev);
+
+	if (!(dev->flags & DF_FIXEDCLASS))
+		devclass_delete_device(dev->devclass, dev);
+
+	dev->state = DS_NOTPRESENT;
+	device_set_driver(dev, NULL);
+	device_set_desc(dev, NULL);
+	device_sysctl_fini(dev);
+
+	return (0);
+}
+
+/**
+ * @brief Tells a driver to quiesce itself.
+ *
+ * This function is a wrapper around the DEVICE_QUIESCE() driver
+ * method. If the call to DEVICE_QUIESCE() succeeds.
+ *
+ * @param dev		the device to quiesce
+ *
+ * @retval 0		success
+ * @retval ENXIO	no driver was found
+ * @retval ENOMEM	memory allocation failure
+ * @retval non-zero	some other unix error code
+ */
+int
+device_quiesce(device_t dev)
+{
+
+	PDEBUG(("%s", DEVICENAME(dev)));
+	if (dev->state == DS_BUSY)
+		return (EBUSY);
+	if (dev->state != DS_ATTACHED)
+		return (0);
+
+	return (DEVICE_QUIESCE(dev));
+}
+
+/**
+ * @brief Notify a device of system shutdown
+ *
+ * This function calls the DEVICE_SHUTDOWN() driver method if the
+ * device currently has an attached driver.
+ *
+ * @returns the value returned by DEVICE_SHUTDOWN()
+ */
+int
+device_shutdown(device_t dev)
+{
+	if (dev->state < DS_ATTACHED)
+		return (0);
+	return (DEVICE_SHUTDOWN(dev));
+}
+
+/**
+ * @brief Set the unit number of a device
+ *
+ * This function can be used to override the unit number used for a
+ * device (e.g. to wire a device to a pre-configured unit number).
+ */
+int
+device_set_unit(device_t dev, int unit)
+{
+	devclass_t dc;
+	int err;
+
+	dc = device_get_devclass(dev);
+	if (unit < dc->maxunit && dc->devices[unit])
+		return (EBUSY);
+	err = devclass_delete_device(dc, dev);
+	if (err)
+		return (err);
+	dev->unit = unit;
+	err = devclass_add_device(dc, dev);
+	if (err)
+		return (err);
+
+	bus_data_generation_update();
+	return (0);
+}
+
+/*======================================*/
+/*
+ * Some useful method implementations to make life easier for bus drivers.
+ */
+
+/**
+ * @brief Initialise a resource list.
+ *
+ * @param rl		the resource list to initialise
+ */
+void
+resource_list_init(struct resource_list *rl)
+{
+	STAILQ_INIT(rl);
+}
+
+/**
+ * @brief Reclaim memory used by a resource list.
+ *
+ * This function frees the memory for all resource entries on the list
+ * (if any).
+ *
+ * @param rl		the resource list to free		
+ */
+void
+resource_list_free(struct resource_list *rl)
+{
+	struct resource_list_entry *rle;
+
+	while ((rle = STAILQ_FIRST(rl)) != NULL) {
+		if (rle->res)
+			panic("resource_list_free: resource entry is busy");
+		STAILQ_REMOVE_HEAD(rl, link);
+		free(rle, M_BUS);
+	}
+}
+
+/**
+ * @brief Add a resource entry.
+ *
+ * This function adds a resource entry using the given @p type, @p
+ * start, @p end and @p count values. A rid value is chosen by
+ * searching sequentially for the first unused rid starting at zero.
+ *
+ * @param rl		the resource list to edit
+ * @param type		the resource entry type (e.g. SYS_RES_MEMORY)
+ * @param start		the start address of the resource
+ * @param end		the end address of the resource
+ * @param count		XXX end-start+1
+ */
+int
+resource_list_add_next(struct resource_list *rl, int type, u_long start,
+    u_long end, u_long count)
+{
+	int rid;
+
+	rid = 0;
+	while (resource_list_find(rl, type, rid) != NULL)
+		rid++;
+	resource_list_add(rl, type, rid, start, end, count);
+	return (rid);
+}
+
+/**
+ * @brief Add or modify a resource entry.
+ *
+ * If an existing entry exists with the same type and rid, it will be
+ * modified using the given values of @p start, @p end and @p
+ * count. If no entry exists, a new one will be created using the
+ * given values.  The resource list entry that matches is then returned.
+ *
+ * @param rl		the resource list to edit
+ * @param type		the resource entry type (e.g. SYS_RES_MEMORY)
+ * @param rid		the resource identifier
+ * @param start		the start address of the resource
+ * @param end		the end address of the resource
+ * @param count		XXX end-start+1
+ */
+struct resource_list_entry *
+resource_list_add(struct resource_list *rl, int type, int rid,
+    u_long start, u_long end, u_long count)
+{
+	struct resource_list_entry *rle;
+
+	rle = resource_list_find(rl, type, rid);
+	if (!rle) {
+		rle = malloc(sizeof(struct resource_list_entry), M_BUS,
+		    M_NOWAIT);
+		if (!rle)
+			panic("resource_list_add: can't record entry");
+		STAILQ_INSERT_TAIL(rl, rle, link);
+		rle->type = type;
+		rle->rid = rid;
+		rle->res = NULL;
+	}
+
+	if (rle->res)
+		panic("resource_list_add: resource entry is busy");
+
+	rle->start = start;
+	rle->end = end;
+	rle->count = count;
+	return (rle);
+}
+
+/**
+ * @brief Find a resource entry by type and rid.
+ *
+ * @param rl		the resource list to search
+ * @param type		the resource entry type (e.g. SYS_RES_MEMORY)
+ * @param rid		the resource identifier
+ *
+ * @returns the resource entry pointer or NULL if there is no such
+ * entry.
+ */
+struct resource_list_entry *
+resource_list_find(struct resource_list *rl, int type, int rid)
+{
+	struct resource_list_entry *rle;
+
+	STAILQ_FOREACH(rle, rl, link) {
+		if (rle->type == type && rle->rid == rid)
+			return (rle);
+	}
+	return (NULL);
+}
+
+/**
+ * @brief Delete a resource entry.
+ *
+ * @param rl		the resource list to edit
+ * @param type		the resource entry type (e.g. SYS_RES_MEMORY)
+ * @param rid		the resource identifier
+ */
+void
+resource_list_delete(struct resource_list *rl, int type, int rid)
+{
+	struct resource_list_entry *rle = resource_list_find(rl, type, rid);
+
+	if (rle) {
+		if (rle->res != NULL)
+			panic("resource_list_delete: resource has not been released");
+		STAILQ_REMOVE(rl, rle, resource_list_entry, link);
+		free(rle, M_BUS);
+	}
+}
+
+/**
+ * @brief Helper function for implementing BUS_ALLOC_RESOURCE()
+ *
+ * Implement BUS_ALLOC_RESOURCE() by looking up a resource from the list
+ * and passing the allocation up to the parent of @p bus. This assumes
+ * that the first entry of @c device_get_ivars(child) is a struct
+ * resource_list. This also handles 'passthrough' allocations where a
+ * child is a remote descendant of bus by passing the allocation up to
+ * the parent of bus.
+ *
+ * Typically, a bus driver would store a list of child resources
+ * somewhere in the child device's ivars (see device_get_ivars()) and
+ * its implementation of BUS_ALLOC_RESOURCE() would find that list and
+ * then call resource_list_alloc() to perform the allocation.
+ *
+ * @param rl		the resource list to allocate from
+ * @param bus		the parent device of @p child
+ * @param child		the device which is requesting an allocation
+ * @param type		the type of resource to allocate
+ * @param rid		a pointer to the resource identifier
+ * @param start		hint at the start of the resource range - pass
+ *			@c 0UL for any start address
+ * @param end		hint at the end of the resource range - pass
+ *			@c ~0UL for any end address
+ * @param count		hint at the size of range required - pass @c 1
+ *			for any size
+ * @param flags		any extra flags to control the resource
+ *			allocation - see @c RF_XXX flags in
+ *			<sys/rman.h> for details
+ * 
+ * @returns		the resource which was allocated or @c NULL if no
+ *			resource could be allocated
+ */
+struct resource *
+resource_list_alloc(struct resource_list *rl, device_t bus, device_t child,
+    int type, int *rid, u_long start, u_long end, u_long count, u_int flags)
+{
+	struct resource_list_entry *rle = NULL;
+	int passthrough = (device_get_parent(child) != bus);
+	int isdefault = (start == 0UL && end == ~0UL);
+
+	if (passthrough) {
+		return (BUS_ALLOC_RESOURCE(device_get_parent(bus), child,
+		    type, rid, start, end, count, flags));
+	}
+
+	rle = resource_list_find(rl, type, *rid);
+
+	if (!rle)
+		return (NULL);		/* no resource of that type/rid */
+
+	if (rle->res)
+		panic("resource_list_alloc: resource entry is busy");
+
+	if (isdefault) {
+		start = rle->start;
+		count = ulmax(count, rle->count);
+		end = ulmax(rle->end, start + count - 1);
+	}
+
+	rle->res = BUS_ALLOC_RESOURCE(device_get_parent(bus), child,
+	    type, rid, start, end, count, flags);
+
+	/*
+	 * Record the new range.
+	 */
+	if (rle->res) {
+		rle->start = rman_get_start(rle->res);
+		rle->end = rman_get_end(rle->res);
+		rle->count = count;
+	}
+
+	return (rle->res);
+}
+
+/**
+ * @brief Helper function for implementing BUS_RELEASE_RESOURCE()
+ * 
+ * Implement BUS_RELEASE_RESOURCE() using a resource list. Normally
+ * used with resource_list_alloc().
+ * 
+ * @param rl		the resource list which was allocated from
+ * @param bus		the parent device of @p child
+ * @param child		the device which is requesting a release
+ * @param type		the type of resource to allocate
+ * @param rid		the resource identifier
+ * @param res		the resource to release
+ * 
+ * @retval 0		success
+ * @retval non-zero	a standard unix error code indicating what
+ *			error condition prevented the operation
+ */
+int
+resource_list_release(struct resource_list *rl, device_t bus, device_t child,
+    int type, int rid, struct resource *res)
+{
+	struct resource_list_entry *rle = NULL;
+	int passthrough = (device_get_parent(child) != bus);
+	int error;
+
+	if (passthrough) {
+		return (BUS_RELEASE_RESOURCE(device_get_parent(bus), child,
+		    type, rid, res));
+	}
+
+	rle = resource_list_find(rl, type, rid);
+
+	if (!rle)
+		panic("resource_list_release: can't find resource");
+	if (!rle->res)
+		panic("resource_list_release: resource entry is not busy");
+
+	error = BUS_RELEASE_RESOURCE(device_get_parent(bus), child,
+	    type, rid, res);
+	if (error)
+		return (error);
+
+	rle->res = NULL;
+	return (0);
+}
+
+/**
+ * @brief Print a description of resources in a resource list
+ *
+ * Print all resources of a specified type, for use in BUS_PRINT_CHILD().
+ * The name is printed if at least one resource of the given type is available.
+ * The format is used to print resource start and end.
+ *
+ * @param rl		the resource list to print
+ * @param name		the name of @p type, e.g. @c "memory"
+ * @param type		type type of resource entry to print
+ * @param format	printf(9) format string to print resource
+ *			start and end values
+ * 
+ * @returns		the number of characters printed
+ */
+int
+resource_list_print_type(struct resource_list *rl, const char *name, int type,
+    const char *format)
+{
+	struct resource_list_entry *rle;
+	int printed, retval;
+
+	printed = 0;
+	retval = 0;
+	/* Yes, this is kinda cheating */
+	STAILQ_FOREACH(rle, rl, link) {
+		if (rle->type == type) {
+			if (printed == 0)
+				retval += printf(" %s ", name);
+			else
+				retval += printf(",");
+			printed++;
+			retval += printf(format, rle->start);
+			if (rle->count > 1) {
+				retval += printf("-");
+				retval += printf(format, rle->start +
+						 rle->count - 1);
+			}
+		}
+	}
+	return (retval);
+}
+
+/**
+ * @brief Releases all the resources in a list.
+ *
+ * @param rl		The resource list to purge.
+ * 
+ * @returns		nothing
+ */
+void
+resource_list_purge(struct resource_list *rl)
+{
+	struct resource_list_entry *rle;
+
+	while ((rle = STAILQ_FIRST(rl)) != NULL) {
+		if (rle->res)
+			bus_release_resource(rman_get_device(rle->res),
+			    rle->type, rle->rid, rle->res);
+		STAILQ_REMOVE_HEAD(rl, link);
+		free(rle, M_BUS);
+	}
+}
+
+device_t
+bus_generic_add_child(device_t dev, u_int order, const char *name, int unit)
+{
+
+	return (device_add_child_ordered(dev, order, name, unit));
+}
+
+/**
+ * @brief Helper function for implementing DEVICE_PROBE()
+ *
+ * This function can be used to help implement the DEVICE_PROBE() for
+ * a bus (i.e. a device which has other devices attached to it). It
+ * calls the DEVICE_IDENTIFY() method of each driver in the device's
+ * devclass.
+ */
+int
+bus_generic_probe(device_t dev)
+{
+	devclass_t dc = dev->devclass;
+	driverlink_t dl;
+
+	TAILQ_FOREACH(dl, &dc->drivers, link) {
+		/*
+		 * If this driver's pass is too high, then ignore it.
+		 * For most drivers in the default pass, this will
+		 * never be true.  For early-pass drivers they will
+		 * only call the identify routines of eligible drivers
+		 * when this routine is called.  Drivers for later
+		 * passes should have their identify routines called
+		 * on early-pass busses during BUS_NEW_PASS().
+		 */
+		if (dl->pass > bus_current_pass)
+				continue;
+		DEVICE_IDENTIFY(dl->driver, dev);
+	}
+
+	return (0);
+}
+
+/**
+ * @brief Helper function for implementing DEVICE_ATTACH()
+ *
+ * This function can be used to help implement the DEVICE_ATTACH() for
+ * a bus. It calls device_probe_and_attach() for each of the device's
+ * children.
+ */
+int
+bus_generic_attach(device_t dev)
+{
+	device_t child;
+
+	TAILQ_FOREACH(child, &dev->children, link) {
+		device_probe_and_attach(child);
+	}
+
+	return (0);
+}
+
+/**
+ * @brief Helper function for implementing DEVICE_DETACH()
+ *
+ * This function can be used to help implement the DEVICE_DETACH() for
+ * a bus. It calls device_detach() for each of the device's
+ * children.
+ */
+int
+bus_generic_detach(device_t dev)
+{
+	device_t child;
+	int error;
+
+	if (dev->state != DS_ATTACHED)
+		return (EBUSY);
+
+	TAILQ_FOREACH(child, &dev->children, link) {
+		if ((error = device_detach(child)) != 0)
+			return (error);
+	}
+
+	return (0);
+}
+
+/**
+ * @brief Helper function for implementing DEVICE_SHUTDOWN()
+ *
+ * This function can be used to help implement the DEVICE_SHUTDOWN()
+ * for a bus. It calls device_shutdown() for each of the device's
+ * children.
+ */
+int
+bus_generic_shutdown(device_t dev)
+{
+	device_t child;
+
+	TAILQ_FOREACH(child, &dev->children, link) {
+		device_shutdown(child);
+	}
+
+	return (0);
+}
+
+/**
+ * @brief Helper function for implementing DEVICE_SUSPEND()
+ *
+ * This function can be used to help implement the DEVICE_SUSPEND()
+ * for a bus. It calls DEVICE_SUSPEND() for each of the device's
+ * children. If any call to DEVICE_SUSPEND() fails, the suspend
+ * operation is aborted and any devices which were suspended are
+ * resumed immediately by calling their DEVICE_RESUME() methods.
+ */
+int
+bus_generic_suspend(device_t dev)
+{
+	int		error;
+	device_t	child, child2;
+
+	TAILQ_FOREACH(child, &dev->children, link) {
+		error = DEVICE_SUSPEND(child);
+		if (error) {
+			for (child2 = TAILQ_FIRST(&dev->children);
+			     child2 && child2 != child;
+			     child2 = TAILQ_NEXT(child2, link))
+				DEVICE_RESUME(child2);
+			return (error);
+		}
+	}
+	return (0);
+}
+
+/**
+ * @brief Helper function for implementing DEVICE_RESUME()
+ *
+ * This function can be used to help implement the DEVICE_RESUME() for
+ * a bus. It calls DEVICE_RESUME() on each of the device's children.
+ */
+int
+bus_generic_resume(device_t dev)
+{
+	device_t	child;
+
+	TAILQ_FOREACH(child, &dev->children, link) {
+		DEVICE_RESUME(child);
+		/* if resume fails, there's nothing we can usefully do... */
+	}
+	return (0);
+}
+
+/**
+ * @brief Helper function for implementing BUS_PRINT_CHILD().
+ *
+ * This function prints the first part of the ascii representation of
+ * @p child, including its name, unit and description (if any - see
+ * device_set_desc()).
+ *
+ * @returns the number of characters printed
+ */
+int
+bus_print_child_header(device_t dev, device_t child)
+{
+	int	retval = 0;
+
+	if (device_get_desc(child)) {
+		retval += device_printf(child, "<%s>", device_get_desc(child));
+	} else {
+		retval += printf("%s", device_get_nameunit(child));
+	}
+
+	return (retval);
+}
+
+/**
+ * @brief Helper function for implementing BUS_PRINT_CHILD().
+ *
+ * This function prints the last part of the ascii representation of
+ * @p child, which consists of the string @c " on " followed by the
+ * name and unit of the @p dev.
+ *
+ * @returns the number of characters printed
+ */
+int
+bus_print_child_footer(device_t dev, device_t child)
+{
+	return (printf(" on %s\n", device_get_nameunit(dev)));
+}
+
+/**
+ * @brief Helper function for implementing BUS_PRINT_CHILD().
+ *
+ * This function simply calls bus_print_child_header() followed by
+ * bus_print_child_footer().
+ *
+ * @returns the number of characters printed
+ */
+int
+bus_generic_print_child(device_t dev, device_t child)
+{
+	int	retval = 0;
+
+	retval += bus_print_child_header(dev, child);
+	retval += bus_print_child_footer(dev, child);
+
+	return (retval);
+}
+
+/**
+ * @brief Stub function for implementing BUS_READ_IVAR().
+ * 
+ * @returns ENOENT
+ */
+int
+bus_generic_read_ivar(device_t dev, device_t child, int index,
+    uintptr_t * result)
+{
+	return (ENOENT);
+}
+
+/**
+ * @brief Stub function for implementing BUS_WRITE_IVAR().
+ * 
+ * @returns ENOENT
+ */
+int
+bus_generic_write_ivar(device_t dev, device_t child, int index,
+    uintptr_t value)
+{
+	return (ENOENT);
+}
+
+/**
+ * @brief Stub function for implementing BUS_GET_RESOURCE_LIST().
+ * 
+ * @returns NULL
+ */
+struct resource_list *
+bus_generic_get_resource_list(device_t dev, device_t child)
+{
+	return (NULL);
+}
+
+/**
+ * @brief Helper function for implementing BUS_DRIVER_ADDED().
+ *
+ * This implementation of BUS_DRIVER_ADDED() simply calls the driver's
+ * DEVICE_IDENTIFY() method to allow it to add new children to the bus
+ * and then calls device_probe_and_attach() for each unattached child.
+ */
+void
+bus_generic_driver_added(device_t dev, driver_t *driver)
+{
+	device_t child;
+
+	DEVICE_IDENTIFY(driver, dev);
+	TAILQ_FOREACH(child, &dev->children, link) {
+		if (child->state == DS_NOTPRESENT ||
+		    (child->flags & DF_REBID))
+			device_probe_and_attach(child);
+	}
+}
+
+/**
+ * @brief Helper function for implementing BUS_NEW_PASS().
+ *
+ * This implementing of BUS_NEW_PASS() first calls the identify
+ * routines for any drivers that probe at the current pass.  Then it
+ * walks the list of devices for this bus.  If a device is already
+ * attached, then it calls BUS_NEW_PASS() on that device.  If the
+ * device is not already attached, it attempts to attach a driver to
+ * it.
+ */
+void
+bus_generic_new_pass(device_t dev)
+{
+	driverlink_t dl;
+	devclass_t dc;
+	device_t child;
+
+	dc = dev->devclass;
+	TAILQ_FOREACH(dl, &dc->drivers, link) {
+		if (dl->pass == bus_current_pass)
+			DEVICE_IDENTIFY(dl->driver, dev);
+	}
+	TAILQ_FOREACH(child, &dev->children, link) {
+		if (child->state >= DS_ATTACHED)
+			BUS_NEW_PASS(child);
+		else if (child->state == DS_NOTPRESENT)
+			device_probe_and_attach(child);
+	}
+}
+
+/**
+ * @brief Helper function for implementing BUS_SETUP_INTR().
+ *
+ * This simple implementation of BUS_SETUP_INTR() simply calls the
+ * BUS_SETUP_INTR() method of the parent of @p dev.
+ */
+int
+bus_generic_setup_intr(device_t dev, device_t child, struct resource *irq,
+    int flags, driver_filter_t *filter, driver_intr_t *intr, void *arg, 
+    void **cookiep)
+{
+	/* Propagate up the bus hierarchy until someone handles it. */
+	if (dev->parent)
+		return (BUS_SETUP_INTR(dev->parent, child, irq, flags,
+		    filter, intr, arg, cookiep));
+	return (EINVAL);
+}
+
+/**
+ * @brief Helper function for implementing BUS_TEARDOWN_INTR().
+ *
+ * This simple implementation of BUS_TEARDOWN_INTR() simply calls the
+ * BUS_TEARDOWN_INTR() method of the parent of @p dev.
+ */
+int
+bus_generic_teardown_intr(device_t dev, device_t child, struct resource *irq,
+    void *cookie)
+{
+	/* Propagate up the bus hierarchy until someone handles it. */
+	if (dev->parent)
+		return (BUS_TEARDOWN_INTR(dev->parent, child, irq, cookie));
+	return (EINVAL);
+}
+
+/**
+ * @brief Helper function for implementing BUS_ALLOC_RESOURCE().
+ *
+ * This simple implementation of BUS_ALLOC_RESOURCE() simply calls the
+ * BUS_ALLOC_RESOURCE() method of the parent of @p dev.
+ */
+struct resource *
+bus_generic_alloc_resource(device_t dev, device_t child, int type, int *rid,
+    u_long start, u_long end, u_long count, u_int flags)
+{
+	/* Propagate up the bus hierarchy until someone handles it. */
+	if (dev->parent)
+		return (BUS_ALLOC_RESOURCE(dev->parent, child, type, rid,
+		    start, end, count, flags));
+	return (NULL);
+}
+
+/**
+ * @brief Helper function for implementing BUS_RELEASE_RESOURCE().
+ *
+ * This simple implementation of BUS_RELEASE_RESOURCE() simply calls the
+ * BUS_RELEASE_RESOURCE() method of the parent of @p dev.
+ */
+int
+bus_generic_release_resource(device_t dev, device_t child, int type, int rid,
+    struct resource *r)
+{
+	/* Propagate up the bus hierarchy until someone handles it. */
+	if (dev->parent)
+		return (BUS_RELEASE_RESOURCE(dev->parent, child, type, rid,
+		    r));
+	return (EINVAL);
+}
+
+/**
+ * @brief Helper function for implementing BUS_ACTIVATE_RESOURCE().
+ *
+ * This simple implementation of BUS_ACTIVATE_RESOURCE() simply calls the
+ * BUS_ACTIVATE_RESOURCE() method of the parent of @p dev.
+ */
+int
+bus_generic_activate_resource(device_t dev, device_t child, int type, int rid,
+    struct resource *r)
+{
+	/* Propagate up the bus hierarchy until someone handles it. */
+	if (dev->parent)
+		return (BUS_ACTIVATE_RESOURCE(dev->parent, child, type, rid,
+		    r));
+	return (EINVAL);
+}
+
+/**
+ * @brief Helper function for implementing BUS_DEACTIVATE_RESOURCE().
+ *
+ * This simple implementation of BUS_DEACTIVATE_RESOURCE() simply calls the
+ * BUS_DEACTIVATE_RESOURCE() method of the parent of @p dev.
+ */
+int
+bus_generic_deactivate_resource(device_t dev, device_t child, int type,
+    int rid, struct resource *r)
+{
+	/* Propagate up the bus hierarchy until someone handles it. */
+	if (dev->parent)
+		return (BUS_DEACTIVATE_RESOURCE(dev->parent, child, type, rid,
+		    r));
+	return (EINVAL);
+}
+
+/**
+ * @brief Helper function for implementing BUS_BIND_INTR().
+ *
+ * This simple implementation of BUS_BIND_INTR() simply calls the
+ * BUS_BIND_INTR() method of the parent of @p dev.
+ */
+int
+bus_generic_bind_intr(device_t dev, device_t child, struct resource *irq,
+    int cpu)
+{
+
+	/* Propagate up the bus hierarchy until someone handles it. */
+	if (dev->parent)
+		return (BUS_BIND_INTR(dev->parent, child, irq, cpu));
+	return (EINVAL);
+}
+
+/**
+ * @brief Helper function for implementing BUS_CONFIG_INTR().
+ *
+ * This simple implementation of BUS_CONFIG_INTR() simply calls the
+ * BUS_CONFIG_INTR() method of the parent of @p dev.
+ */
+int
+bus_generic_config_intr(device_t dev, int irq, enum intr_trigger trig,
+    enum intr_polarity pol)
+{
+
+	/* Propagate up the bus hierarchy until someone handles it. */
+	if (dev->parent)
+		return (BUS_CONFIG_INTR(dev->parent, irq, trig, pol));
+	return (EINVAL);
+}
+
+/**
+ * @brief Helper function for implementing BUS_DESCRIBE_INTR().
+ *
+ * This simple implementation of BUS_DESCRIBE_INTR() simply calls the
+ * BUS_DESCRIBE_INTR() method of the parent of @p dev.
+ */
+int
+bus_generic_describe_intr(device_t dev, device_t child, struct resource *irq,
+    void *cookie, const char *descr)
+{
+
+	/* Propagate up the bus hierarchy until someone handles it. */
+	if (dev->parent)
+		return (BUS_DESCRIBE_INTR(dev->parent, child, irq, cookie,
+		    descr));
+	return (EINVAL);
+}
+
+/**
+ * @brief Helper function for implementing BUS_GET_DMA_TAG().
+ *
+ * This simple implementation of BUS_GET_DMA_TAG() simply calls the
+ * BUS_GET_DMA_TAG() method of the parent of @p dev.
+ */
+bus_dma_tag_t
+bus_generic_get_dma_tag(device_t dev, device_t child)
+{
+
+	/* Propagate up the bus hierarchy until someone handles it. */
+	if (dev->parent != NULL)
+		return (BUS_GET_DMA_TAG(dev->parent, child));
+	return (NULL);
+}
+
+/**
+ * @brief Helper function for implementing BUS_GET_RESOURCE().
+ *
+ * This implementation of BUS_GET_RESOURCE() uses the
+ * resource_list_find() function to do most of the work. It calls
+ * BUS_GET_RESOURCE_LIST() to find a suitable resource list to
+ * search.
+ */
+int
+bus_generic_rl_get_resource(device_t dev, device_t child, int type, int rid,
+    u_long *startp, u_long *countp)
+{
+	struct resource_list *		rl = NULL;
+	struct resource_list_entry *	rle = NULL;
+
+	rl = BUS_GET_RESOURCE_LIST(dev, child);
+	if (!rl)
+		return (EINVAL);
+
+	rle = resource_list_find(rl, type, rid);
+	if (!rle)
+		return (ENOENT);
+
+	if (startp)
+		*startp = rle->start;
+	if (countp)
+		*countp = rle->count;
+
+	return (0);
+}
+
+/**
+ * @brief Helper function for implementing BUS_SET_RESOURCE().
+ *
+ * This implementation of BUS_SET_RESOURCE() uses the
+ * resource_list_add() function to do most of the work. It calls
+ * BUS_GET_RESOURCE_LIST() to find a suitable resource list to
+ * edit.
+ */
+int
+bus_generic_rl_set_resource(device_t dev, device_t child, int type, int rid,
+    u_long start, u_long count)
+{
+	struct resource_list *		rl = NULL;
+
+	rl = BUS_GET_RESOURCE_LIST(dev, child);
+	if (!rl)
+		return (EINVAL);
+
+	resource_list_add(rl, type, rid, start, (start + count - 1), count);
+
+	return (0);
+}
+
+/**
+ * @brief Helper function for implementing BUS_DELETE_RESOURCE().
+ *
+ * This implementation of BUS_DELETE_RESOURCE() uses the
+ * resource_list_delete() function to do most of the work. It calls
+ * BUS_GET_RESOURCE_LIST() to find a suitable resource list to
+ * edit.
+ */
+void
+bus_generic_rl_delete_resource(device_t dev, device_t child, int type, int rid)
+{
+	struct resource_list *		rl = NULL;
+
+	rl = BUS_GET_RESOURCE_LIST(dev, child);
+	if (!rl)
+		return;
+
+	resource_list_delete(rl, type, rid);
+
+	return;
+}
+
+/**
+ * @brief Helper function for implementing BUS_RELEASE_RESOURCE().
+ *
+ * This implementation of BUS_RELEASE_RESOURCE() uses the
+ * resource_list_release() function to do most of the work. It calls
+ * BUS_GET_RESOURCE_LIST() to find a suitable resource list.
+ */
+int
+bus_generic_rl_release_resource(device_t dev, device_t child, int type,
+    int rid, struct resource *r)
+{
+	struct resource_list *		rl = NULL;
+
+	rl = BUS_GET_RESOURCE_LIST(dev, child);
+	if (!rl)
+		return (EINVAL);
+
+	return (resource_list_release(rl, dev, child, type, rid, r));
+}
+
+/**
+ * @brief Helper function for implementing BUS_ALLOC_RESOURCE().
+ *
+ * This implementation of BUS_ALLOC_RESOURCE() uses the
+ * resource_list_alloc() function to do most of the work. It calls
+ * BUS_GET_RESOURCE_LIST() to find a suitable resource list.
+ */
+struct resource *
+bus_generic_rl_alloc_resource(device_t dev, device_t child, int type,
+    int *rid, u_long start, u_long end, u_long count, u_int flags)
+{
+	struct resource_list *		rl = NULL;
+
+	rl = BUS_GET_RESOURCE_LIST(dev, child);
+	if (!rl)
+		return (NULL);
+
+	return (resource_list_alloc(rl, dev, child, type, rid,
+	    start, end, count, flags));
+}
+
+/**
+ * @brief Helper function for implementing BUS_CHILD_PRESENT().
+ *
+ * This simple implementation of BUS_CHILD_PRESENT() simply calls the
+ * BUS_CHILD_PRESENT() method of the parent of @p dev.
+ */
+int
+bus_generic_child_present(device_t dev, device_t child)
+{
+	return (BUS_CHILD_PRESENT(device_get_parent(dev), dev));
+}
+
+/*
+ * Some convenience functions to make it easier for drivers to use the
+ * resource-management functions.  All these really do is hide the
+ * indirection through the parent's method table, making for slightly
+ * less-wordy code.  In the future, it might make sense for this code
+ * to maintain some sort of a list of resources allocated by each device.
+ */
+
+int
+bus_alloc_resources(device_t dev, struct resource_spec *rs,
+    struct resource **res)
+{
+	int i;
+
+	for (i = 0; rs[i].type != -1; i++)
+		res[i] = NULL;
+	for (i = 0; rs[i].type != -1; i++) {
+		res[i] = bus_alloc_resource_any(dev,
+		    rs[i].type, &rs[i].rid, rs[i].flags);
+		if (res[i] == NULL && !(rs[i].flags & RF_OPTIONAL)) {
+			bus_release_resources(dev, rs, res);
+			return (ENXIO);
+		}
+	}
+	return (0);
+}
+
+void
+bus_release_resources(device_t dev, const struct resource_spec *rs,
+    struct resource **res)
+{
+	int i;
+
+	for (i = 0; rs[i].type != -1; i++)
+		if (res[i] != NULL) {
+			bus_release_resource(
+			    dev, rs[i].type, rs[i].rid, res[i]);
+			res[i] = NULL;
+		}
+}
+
+/**
+ * @brief Wrapper function for BUS_ALLOC_RESOURCE().
+ *
+ * This function simply calls the BUS_ALLOC_RESOURCE() method of the
+ * parent of @p dev.
+ */
+struct resource *
+bus_alloc_resource(device_t dev, int type, int *rid, u_long start, u_long end,
+    u_long count, u_int flags)
+{
+	if (dev->parent == NULL)
+		return (NULL);
+	return (BUS_ALLOC_RESOURCE(dev->parent, dev, type, rid, start, end,
+	    count, flags));
+}
+
+/**
+ * @brief Wrapper function for BUS_ACTIVATE_RESOURCE().
+ *
+ * This function simply calls the BUS_ACTIVATE_RESOURCE() method of the
+ * parent of @p dev.
+ */
+int
+bus_activate_resource(device_t dev, int type, int rid, struct resource *r)
+{
+	if (dev->parent == NULL)
+		return (EINVAL);
+	return (BUS_ACTIVATE_RESOURCE(dev->parent, dev, type, rid, r));
+}
+
+/**
+ * @brief Wrapper function for BUS_DEACTIVATE_RESOURCE().
+ *
+ * This function simply calls the BUS_DEACTIVATE_RESOURCE() method of the
+ * parent of @p dev.
+ */
+int
+bus_deactivate_resource(device_t dev, int type, int rid, struct resource *r)
+{
+	if (dev->parent == NULL)
+		return (EINVAL);
+	return (BUS_DEACTIVATE_RESOURCE(dev->parent, dev, type, rid, r));
+}
+
+/**
+ * @brief Wrapper function for BUS_RELEASE_RESOURCE().
+ *
+ * This function simply calls the BUS_RELEASE_RESOURCE() method of the
+ * parent of @p dev.
+ */
+int
+bus_release_resource(device_t dev, int type, int rid, struct resource *r)
+{
+	if (dev->parent == NULL)
+		return (EINVAL);
+	return (BUS_RELEASE_RESOURCE(dev->parent, dev, type, rid, r));
+}
+
+/**
+ * @brief Wrapper function for BUS_SETUP_INTR().
+ *
+ * This function simply calls the BUS_SETUP_INTR() method of the
+ * parent of @p dev.
+ */
+int
+bus_setup_intr(device_t dev, struct resource *r, int flags,
+    driver_filter_t filter, driver_intr_t handler, void *arg, void **cookiep)
+{
+	int error;
+
+	if (dev->parent == NULL)
+		return (EINVAL);
+	error = BUS_SETUP_INTR(dev->parent, dev, r, flags, filter, handler,
+	    arg, cookiep);
+	if (error != 0)
+		return (error);
+	if (handler != NULL && !(flags & INTR_MPSAFE))
+		device_printf(dev, "[GIANT-LOCKED]\n");
+	if (bootverbose && (flags & INTR_MPSAFE))
+		device_printf(dev, "[MPSAFE]\n");
+	if (filter != NULL) {
+		if (handler == NULL)
+			device_printf(dev, "[FILTER]\n");
+		else 
+			device_printf(dev, "[FILTER+ITHREAD]\n");
+	} else 
+		device_printf(dev, "[ITHREAD]\n");
+	return (0);
+}
+
+/**
+ * @brief Wrapper function for BUS_TEARDOWN_INTR().
+ *
+ * This function simply calls the BUS_TEARDOWN_INTR() method of the
+ * parent of @p dev.
+ */
+int
+bus_teardown_intr(device_t dev, struct resource *r, void *cookie)
+{
+	if (dev->parent == NULL)
+		return (EINVAL);
+	return (BUS_TEARDOWN_INTR(dev->parent, dev, r, cookie));
+}
+
+/**
+ * @brief Wrapper function for BUS_BIND_INTR().
+ *
+ * This function simply calls the BUS_BIND_INTR() method of the
+ * parent of @p dev.
+ */
+int
+bus_bind_intr(device_t dev, struct resource *r, int cpu)
+{
+	if (dev->parent == NULL)
+		return (EINVAL);
+	return (BUS_BIND_INTR(dev->parent, dev, r, cpu));
+}
+
+/**
+ * @brief Wrapper function for BUS_DESCRIBE_INTR().
+ *
+ * This function first formats the requested description into a
+ * temporary buffer and then calls the BUS_DESCRIBE_INTR() method of
+ * the parent of @p dev.
+ */
+int
+bus_describe_intr(device_t dev, struct resource *irq, void *cookie,
+    const char *fmt, ...)
+{
+	va_list ap;
+	char descr[MAXCOMLEN + 1];
+
+	if (dev->parent == NULL)
+		return (EINVAL);
+	va_start(ap, fmt);
+	vsnprintf(descr, sizeof(descr), fmt, ap);
+	va_end(ap);
+	return (BUS_DESCRIBE_INTR(dev->parent, dev, irq, cookie, descr));
+}
+
+/**
+ * @brief Wrapper function for BUS_SET_RESOURCE().
+ *
+ * This function simply calls the BUS_SET_RESOURCE() method of the
+ * parent of @p dev.
+ */
+int
+bus_set_resource(device_t dev, int type, int rid,
+    u_long start, u_long count)
+{
+	return (BUS_SET_RESOURCE(device_get_parent(dev), dev, type, rid,
+	    start, count));
+}
+
+/**
+ * @brief Wrapper function for BUS_GET_RESOURCE().
+ *
+ * This function simply calls the BUS_GET_RESOURCE() method of the
+ * parent of @p dev.
+ */
+int
+bus_get_resource(device_t dev, int type, int rid,
+    u_long *startp, u_long *countp)
+{
+	return (BUS_GET_RESOURCE(device_get_parent(dev), dev, type, rid,
+	    startp, countp));
+}
+
+/**
+ * @brief Wrapper function for BUS_GET_RESOURCE().
+ *
+ * This function simply calls the BUS_GET_RESOURCE() method of the
+ * parent of @p dev and returns the start value.
+ */
+u_long
+bus_get_resource_start(device_t dev, int type, int rid)
+{
+	u_long start, count;
+	int error;
+
+	error = BUS_GET_RESOURCE(device_get_parent(dev), dev, type, rid,
+	    &start, &count);
+	if (error)
+		return (0);
+	return (start);
+}
+
+/**
+ * @brief Wrapper function for BUS_GET_RESOURCE().
+ *
+ * This function simply calls the BUS_GET_RESOURCE() method of the
+ * parent of @p dev and returns the count value.
+ */
+u_long
+bus_get_resource_count(device_t dev, int type, int rid)
+{
+	u_long start, count;
+	int error;
+
+	error = BUS_GET_RESOURCE(device_get_parent(dev), dev, type, rid,
+	    &start, &count);
+	if (error)
+		return (0);
+	return (count);
+}
+
+/**
+ * @brief Wrapper function for BUS_DELETE_RESOURCE().
+ *
+ * This function simply calls the BUS_DELETE_RESOURCE() method of the
+ * parent of @p dev.
+ */
+void
+bus_delete_resource(device_t dev, int type, int rid)
+{
+	BUS_DELETE_RESOURCE(device_get_parent(dev), dev, type, rid);
+}
+
+/**
+ * @brief Wrapper function for BUS_CHILD_PRESENT().
+ *
+ * This function simply calls the BUS_CHILD_PRESENT() method of the
+ * parent of @p dev.
+ */
+int
+bus_child_present(device_t child)
+{
+	return (BUS_CHILD_PRESENT(device_get_parent(child), child));
+}
+
+/**
+ * @brief Wrapper function for BUS_CHILD_PNPINFO_STR().
+ *
+ * This function simply calls the BUS_CHILD_PNPINFO_STR() method of the
+ * parent of @p dev.
+ */
+int
+bus_child_pnpinfo_str(device_t child, char *buf, size_t buflen)
+{
+	device_t parent;
+
+	parent = device_get_parent(child);
+	if (parent == NULL) {
+		*buf = '\0';
+		return (0);
+	}
+	return (BUS_CHILD_PNPINFO_STR(parent, child, buf, buflen));
+}
+
+/**
+ * @brief Wrapper function for BUS_CHILD_LOCATION_STR().
+ *
+ * This function simply calls the BUS_CHILD_LOCATION_STR() method of the
+ * parent of @p dev.
+ */
+int
+bus_child_location_str(device_t child, char *buf, size_t buflen)
+{
+	device_t parent;
+
+	parent = device_get_parent(child);
+	if (parent == NULL) {
+		*buf = '\0';
+		return (0);
+	}
+	return (BUS_CHILD_LOCATION_STR(parent, child, buf, buflen));
+}
+
+/**
+ * @brief Wrapper function for BUS_GET_DMA_TAG().
+ *
+ * This function simply calls the BUS_GET_DMA_TAG() method of the
+ * parent of @p dev.
+ */
+bus_dma_tag_t
+bus_get_dma_tag(device_t dev)
+{
+	device_t parent;
+
+	parent = device_get_parent(dev);
+	if (parent == NULL)
+		return (NULL);
+	return (BUS_GET_DMA_TAG(parent, dev));
+}
+
+/* Resume all devices and then notify userland that we're up again. */
+static int
+root_resume(device_t dev)
+{
+	int error;
+
+	error = bus_generic_resume(dev);
+	if (error == 0)
+		devctl_notify("kern", "power", "resume", NULL);
+	return (error);
+}
+
+static int
+root_print_child(device_t dev, device_t child)
+{
+	int	retval = 0;
+
+	retval += bus_print_child_header(dev, child);
+	retval += printf("\n");
+
+	return (retval);
+}
+
+static int
+root_setup_intr(device_t dev, device_t child, struct resource *irq, int flags,
+    driver_filter_t *filter, driver_intr_t *intr, void *arg, void **cookiep)
+{
+	/*
+	 * If an interrupt mapping gets to here something bad has happened.
+	 */
+	panic("root_setup_intr");
+}
+
+/*
+ * If we get here, assume that the device is permanant and really is
+ * present in the system.  Removable bus drivers are expected to intercept
+ * this call long before it gets here.  We return -1 so that drivers that
+ * really care can check vs -1 or some ERRNO returned higher in the food
+ * chain.
+ */
+static int
+root_child_present(device_t dev, device_t child)
+{
+	return (-1);
+}
+
+static kobj_method_t root_methods[] = {
+	/* Device interface */
+	KOBJMETHOD(device_shutdown,	bus_generic_shutdown),
+	KOBJMETHOD(device_suspend,	bus_generic_suspend),
+	KOBJMETHOD(device_resume,	root_resume),
+
+	/* Bus interface */
+	KOBJMETHOD(bus_print_child,	root_print_child),
+	KOBJMETHOD(bus_read_ivar,	bus_generic_read_ivar),
+	KOBJMETHOD(bus_write_ivar,	bus_generic_write_ivar),
+	KOBJMETHOD(bus_setup_intr,	root_setup_intr),
+	KOBJMETHOD(bus_child_present,	root_child_present),
+
+	KOBJMETHOD_END
+};
+
+static driver_t root_driver = {
+	"root",
+	root_methods,
+	1,			/* no softc */
+};
+
+device_t	root_bus;
+devclass_t	root_devclass;
+
+static int
+root_bus_module_handler(module_t mod, int what, void* arg)
+{
+	switch (what) {
+	case MOD_LOAD:
+		TAILQ_INIT(&bus_data_devices);
+		kobj_class_compile((kobj_class_t) &root_driver);
+		root_bus = make_device(NULL, "root", 0);
+		root_bus->desc = "System root bus";
+		kobj_init((kobj_t) root_bus, (kobj_class_t) &root_driver);
+		root_bus->driver = &root_driver;
+		root_bus->state = DS_ATTACHED;
+		root_devclass = devclass_find_internal("root", NULL, FALSE);
+		devinit();
+		return (0);
+
+	case MOD_SHUTDOWN:
+		device_shutdown(root_bus);
+		return (0);
+	default:
+		return (EOPNOTSUPP);
+	}
+
+	return (0);
+}
+
+static moduledata_t root_bus_mod = {
+	"rootbus",
+	root_bus_module_handler,
+	NULL
+};
+DECLARE_MODULE(rootbus, root_bus_mod, SI_SUB_DRIVERS, SI_ORDER_FIRST);
+
+/**
+ * @brief Automatically configure devices
+ *
+ * This function begins the autoconfiguration process by calling
+ * device_probe_and_attach() for each child of the @c root0 device.
+ */ 
+void
+root_bus_configure(void)
+{
+
+	PDEBUG(("."));
+
+	/* Eventually this will be split up, but this is sufficient for now. */
+	bus_set_pass(BUS_PASS_DEFAULT);
+}
+
+/**
+ * @brief Module handler for registering device drivers
+ *
+ * This module handler is used to automatically register device
+ * drivers when modules are loaded. If @p what is MOD_LOAD, it calls
+ * devclass_add_driver() for the driver described by the
+ * driver_module_data structure pointed to by @p arg
+ */
+int
+driver_module_handler(module_t mod, int what, void *arg)
+{
+	struct driver_module_data *dmd;
+	devclass_t bus_devclass;
+	kobj_class_t driver;
+	int error, pass;
+
+	dmd = (struct driver_module_data *)arg;
+	bus_devclass = devclass_find_internal(dmd->dmd_busname, NULL, TRUE);
+	error = 0;
+
+	switch (what) {
+	case MOD_LOAD:
+		if (dmd->dmd_chainevh)
+			error = dmd->dmd_chainevh(mod,what,dmd->dmd_chainarg);
+
+		pass = dmd->dmd_pass;
+		driver = dmd->dmd_driver;
+		PDEBUG(("Loading module: driver %s on bus %s (pass %d)",
+		    DRIVERNAME(driver), dmd->dmd_busname, pass));
+		error = devclass_add_driver(bus_devclass, driver, pass,
+		    dmd->dmd_devclass);
+		break;
+
+	case MOD_UNLOAD:
+		PDEBUG(("Unloading module: driver %s from bus %s",
+		    DRIVERNAME(dmd->dmd_driver),
+		    dmd->dmd_busname));
+		error = devclass_delete_driver(bus_devclass,
+		    dmd->dmd_driver);
+
+		if (!error && dmd->dmd_chainevh)
+			error = dmd->dmd_chainevh(mod,what,dmd->dmd_chainarg);
+		break;
+	case MOD_QUIESCE:
+		PDEBUG(("Quiesce module: driver %s from bus %s",
+		    DRIVERNAME(dmd->dmd_driver),
+		    dmd->dmd_busname));
+		error = devclass_quiesce_driver(bus_devclass,
+		    dmd->dmd_driver);
+
+		if (!error && dmd->dmd_chainevh)
+			error = dmd->dmd_chainevh(mod,what,dmd->dmd_chainarg);
+		break;
+	default:
+		error = EOPNOTSUPP;
+		break;
+	}
+
+	return (error);
+}
+
+#ifndef __rtems__
+/**
+ * @brief Enumerate all hinted devices for this bus.
+ *
+ * Walks through the hints for this bus and calls the bus_hinted_child
+ * routine for each one it fines.  It searches first for the specific
+ * bus that's being probed for hinted children (eg isa0), and then for
+ * generic children (eg isa).
+ *
+ * @param	dev	bus device to enumerate
+ */
+void
+bus_enumerate_hinted_children(device_t bus)
+{
+	int i;
+	const char *dname, *busname;
+	int dunit;
+
+	/*
+	 * enumerate all devices on the specific bus
+	 */
+	busname = device_get_nameunit(bus);
+	i = 0;
+	while (resource_find_match(&i, &dname, &dunit, "at", busname) == 0)
+		BUS_HINTED_CHILD(bus, dname, dunit);
+
+	/*
+	 * and all the generic ones.
+	 */
+	busname = device_get_name(bus);
+	i = 0;
+	while (resource_find_match(&i, &dname, &dunit, "at", busname) == 0)
+		BUS_HINTED_CHILD(bus, dname, dunit);
+}
+#endif /* __rtems__ */
+
+#ifdef BUS_DEBUG
+
+/* the _short versions avoid iteration by not calling anything that prints
+ * more than oneliners. I love oneliners.
+ */
+
+static void
+print_device_short(device_t dev, int indent)
+{
+	if (!dev)
+		return;
+
+	indentprintf(("device %d: <%s> %sparent,%schildren,%s%s%s%s%s,%sivars,%ssoftc,busy=%d\n",
+	    dev->unit, dev->desc,
+	    (dev->parent? "":"no "),
+	    (TAILQ_EMPTY(&dev->children)? "no ":""),
+	    (dev->flags&DF_ENABLED? "enabled,":"disabled,"),
+	    (dev->flags&DF_FIXEDCLASS? "fixed,":""),
+	    (dev->flags&DF_WILDCARD? "wildcard,":""),
+	    (dev->flags&DF_DESCMALLOCED? "descmalloced,":""),
+	    (dev->flags&DF_REBID? "rebiddable,":""),
+	    (dev->ivars? "":"no "),
+	    (dev->softc? "":"no "),
+	    dev->busy));
+}
+
+static void
+print_device(device_t dev, int indent)
+{
+	if (!dev)
+		return;
+
+	print_device_short(dev, indent);
+
+	indentprintf(("Parent:\n"));
+	print_device_short(dev->parent, indent+1);
+	indentprintf(("Driver:\n"));
+	print_driver_short(dev->driver, indent+1);
+	indentprintf(("Devclass:\n"));
+	print_devclass_short(dev->devclass, indent+1);
+}
+
+void
+print_device_tree_short(device_t dev, int indent)
+/* print the device and all its children (indented) */
+{
+	device_t child;
+
+	if (!dev)
+		return;
+
+	print_device_short(dev, indent);
+
+	TAILQ_FOREACH(child, &dev->children, link) {
+		print_device_tree_short(child, indent+1);
+	}
+}
+
+void
+print_device_tree(device_t dev, int indent)
+/* print the device and all its children (indented) */
+{
+	device_t child;
+
+	if (!dev)
+		return;
+
+	print_device(dev, indent);
+
+	TAILQ_FOREACH(child, &dev->children, link) {
+		print_device_tree(child, indent+1);
+	}
+}
+
+static void
+print_driver_short(driver_t *driver, int indent)
+{
+	if (!driver)
+		return;
+
+	indentprintf(("driver %s: softc size = %zd\n",
+	    driver->name, driver->size));
+}
+
+static void
+print_driver(driver_t *driver, int indent)
+{
+	if (!driver)
+		return;
+
+	print_driver_short(driver, indent);
+}
+
+
+static void
+print_driver_list(driver_list_t drivers, int indent)
+{
+	driverlink_t driver;
+
+	TAILQ_FOREACH(driver, &drivers, link) {
+		print_driver(driver->driver, indent);
+	}
+}
+
+static void
+print_devclass_short(devclass_t dc, int indent)
+{
+	if ( !dc )
+		return;
+
+	indentprintf(("devclass %s: max units = %d\n", dc->name, dc->maxunit));
+}
+
+static void
+print_devclass(devclass_t dc, int indent)
+{
+	int i;
+
+	if ( !dc )
+		return;
+
+	print_devclass_short(dc, indent);
+	indentprintf(("Drivers:\n"));
+	print_driver_list(dc->drivers, indent+1);
+
+	indentprintf(("Devices:\n"));
+	for (i = 0; i < dc->maxunit; i++)
+		if (dc->devices[i])
+			print_device(dc->devices[i], indent+1);
+}
+
+void
+print_devclass_list_short(void)
+{
+	devclass_t dc;
+
+	printf("Short listing of devclasses, drivers & devices:\n");
+	TAILQ_FOREACH(dc, &devclasses, link) {
+		print_devclass_short(dc, 0);
+	}
+}
+
+void
+print_devclass_list(void)
+{
+	devclass_t dc;
+
+	printf("Full listing of devclasses, drivers & devices:\n");
+	TAILQ_FOREACH(dc, &devclasses, link) {
+		print_devclass(dc, 0);
+	}
+}
+
+#endif
+
+#ifndef __rtems__
+/*
+ * User-space access to the device tree.
+ *
+ * We implement a small set of nodes:
+ *
+ * hw.bus			Single integer read method to obtain the
+ *				current generation count.
+ * hw.bus.devices		Reads the entire device tree in flat space.
+ * hw.bus.rman			Resource manager interface
+ *
+ * We might like to add the ability to scan devclasses and/or drivers to
+ * determine what else is currently loaded/available.
+ */
+
+static int
+sysctl_bus(SYSCTL_HANDLER_ARGS)
+{
+	struct u_businfo	ubus;
+
+	ubus.ub_version = BUS_USER_VERSION;
+	ubus.ub_generation = bus_data_generation;
+
+	return (SYSCTL_OUT(req, &ubus, sizeof(ubus)));
+}
+SYSCTL_NODE(_hw_bus, OID_AUTO, info, CTLFLAG_RW, sysctl_bus,
+    "bus-related data");
+
+static int
+sysctl_devices(SYSCTL_HANDLER_ARGS)
+{
+	int			*name = (int *)arg1;
+	u_int			namelen = arg2;
+	int			index;
+	struct device		*dev;
+	struct u_device		udev;	/* XXX this is a bit big */
+	int			error;
+
+	if (namelen != 2)
+		return (EINVAL);
+
+	if (bus_data_generation_check(name[0]))
+		return (EINVAL);
+
+	index = name[1];
+
+	/*
+	 * Scan the list of devices, looking for the requested index.
+	 */
+	TAILQ_FOREACH(dev, &bus_data_devices, devlink) {
+		if (index-- == 0)
+			break;
+	}
+	if (dev == NULL)
+		return (ENOENT);
+
+	/*
+	 * Populate the return array.
+	 */
+	bzero(&udev, sizeof(udev));
+	udev.dv_handle = (uintptr_t)dev;
+	udev.dv_parent = (uintptr_t)dev->parent;
+	if (dev->nameunit != NULL)
+		strlcpy(udev.dv_name, dev->nameunit, sizeof(udev.dv_name));
+	if (dev->desc != NULL)
+		strlcpy(udev.dv_desc, dev->desc, sizeof(udev.dv_desc));
+	if (dev->driver != NULL && dev->driver->name != NULL)
+		strlcpy(udev.dv_drivername, dev->driver->name,
+		    sizeof(udev.dv_drivername));
+	bus_child_pnpinfo_str(dev, udev.dv_pnpinfo, sizeof(udev.dv_pnpinfo));
+	bus_child_location_str(dev, udev.dv_location, sizeof(udev.dv_location));
+	udev.dv_devflags = dev->devflags;
+	udev.dv_flags = dev->flags;
+	udev.dv_state = dev->state;
+	error = SYSCTL_OUT(req, &udev, sizeof(udev));
+	return (error);
+}
+
+SYSCTL_NODE(_hw_bus, OID_AUTO, devices, CTLFLAG_RD, sysctl_devices,
+    "system device tree");
+#endif /* __rtems__ */
+
+int
+bus_data_generation_check(int generation)
+{
+	if (generation != bus_data_generation)
+		return (1);
+
+	/* XXX generate optimised lists here? */
+	return (0);
+}
+
+void
+bus_data_generation_update(void)
+{
+	bus_data_generation++;
+}
+
+#ifndef __rtems__
+int
+bus_free_resource(device_t dev, int type, struct resource *r)
+{
+	if (r == NULL)
+		return (0);
+	return (bus_release_resource(dev, type, rman_get_rid(r), r));
+}
+#endif /* __rtems__ */