xref: /freebsd-11-stable/sys/kern/subr_bus.c

/*-
 * Copyright (c) 1997,1998 Doug Rabson
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * $FreeBSD: head/sys/kern/subr_bus.c 86114 2001-11-05 22:27:46Z arr $
 */

#include "opt_bus.h"

#include <sys/param.h>
#include <sys/queue.h>
#include <sys/malloc.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <sys/kobj.h>
#include <sys/bus_private.h>
#include <sys/sysctl.h>
#include <sys/systm.h>
#include <machine/bus.h>
#include <sys/rman.h>
#include <machine/stdarg.h>	/* for device_printf() */

static MALLOC_DEFINE(M_BUS, "bus", "Bus data structures");

#ifdef BUS_DEBUG

static int bus_debug = 1;
SYSCTL_INT(_debug, OID_AUTO, bus_debug, CTLFLAG_RW, &bus_debug, 0,
    "Debug bus code");

#define PDEBUG(a)	if (bus_debug) {printf(__FUNCTION__ ":%d: ", __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

TAILQ_HEAD(,device)	bus_data_devices;
static int bus_data_generation = 1;

kobj_method_t null_methods[] = {
	{ 0, 0 }
};

DEFINE_CLASS(null, null_methods, 0);

/*
 * Devclass implementation
 */

static devclass_list_t devclasses = TAILQ_HEAD_INITIALIZER(devclasses);

static devclass_t
devclass_find_internal(const char *classname, int create)
{
	devclass_t dc;

	PDEBUG(("looking for %s", classname));
	if (!classname)
		return (NULL);

	TAILQ_FOREACH(dc, &devclasses, link) {
		if (!strcmp(dc->name, classname))
			return (dc);
	}

	PDEBUG(("%s not found%s", classname, (create? ", creating": "")));
	if (create) {
		dc = malloc(sizeof(struct devclass) + strlen(classname) + 1,
		    M_BUS, M_NOWAIT|M_ZERO);
		if (!dc)
			return (NULL);
		dc->name = (char*) (dc + 1);
		strcpy(dc->name, classname);
		TAILQ_INIT(&dc->drivers);
		TAILQ_INSERT_TAIL(&devclasses, dc, link);

		bus_data_generation_update();
	}

	return (dc);
}

devclass_t
devclass_create(const char *classname)
{
	return (devclass_find_internal(classname, TRUE));
}

devclass_t
devclass_find(const char *classname)
{
	return (devclass_find_internal(classname, FALSE));
}

int
devclass_add_driver(devclass_t dc, driver_t *driver)
{
	driverlink_t dl;
	int i;

	PDEBUG(("%s", DRIVERNAME(driver)));

	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);

	/*
	 * Make sure the devclass which the driver is implementing exists.
	 */
	devclass_find_internal(driver->name, TRUE);

	dl->driver = driver;
	TAILQ_INSERT_TAIL(&dc->drivers, dl, link);
	driver->refs++;

	/*
	 * Call BUS_DRIVER_ADDED for any existing busses in this class.
	 */
	for (i = 0; i < dc->maxunit; i++)
		if (dc->devices[i])
			BUS_DRIVER_ADDED(dc->devices[i], driver);

	bus_data_generation_update();
	return (0);
}

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);

	driver->refs--;
	if (driver->refs == 0)
		kobj_class_free((kobj_class_t) driver);

	bus_data_generation_update();
	return (0);
}

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);
}

driver_t *
devclass_find_driver(devclass_t dc, const char *classname)
{
	driverlink_t dl;

	dl = devclass_find_driver_internal(dc, classname);
	if (dl)
		return (dl->driver);
	return (NULL);
}

const char *
devclass_get_name(devclass_t dc)
{
	return (dc->name);
}

device_t
devclass_get_device(devclass_t dc, int unit)
{
	if (dc == NULL || unit < 0 || unit >= dc->maxunit)
		return (NULL);
	return (dc->devices[unit]);
}

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));
}

int
devclass_get_devices(devclass_t dc, device_t **devlistp, int *devcountp)
{
	int i;
	int count;
	device_t *list;

	count = 0;
	for (i = 0; i < dc->maxunit; i++)
		if (dc->devices[i])
			count++;

	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);
}

int
devclass_get_maxunit(devclass_t dc)
{
	return (dc->maxunit);
}

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);
}

static int
devclass_alloc_unit(devclass_t dc, int *unitp)
{
	int unit = *unitp;

	PDEBUG(("unit %d in devclass %s", unit, DEVCLANAME(dc)));

	/* 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) {
			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;
		while (unit < dc->maxunit && dc->devices[unit] != NULL)
			unit++;
	}

	/*
	 * 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;
		int newsize;

		newsize = roundup((unit + 1), MINALLOCSIZE / sizeof(device_t));
		newlist = malloc(sizeof(device_t) * newsize, M_BUS, M_NOWAIT);
		if (!newlist)
			return (ENOMEM);
		bcopy(dc->devices, newlist, sizeof(device_t) * dc->maxunit);
		bzero(newlist + dc->maxunit,
		    sizeof(device_t) * (newsize - dc->maxunit));
		if (dc->devices)
			free(dc->devices, M_BUS);
		dc->devices = newlist;
		dc->maxunit = newsize;
	}
	PDEBUG(("now: unit %d in devclass %s", unit, DEVCLANAME(dc)));

	*unitp = unit;
	return (0);
}

static int
devclass_add_device(devclass_t dc, device_t dev)
{
	int buflen, error;

	PDEBUG(("%s in devclass %s", DEVICENAME(dev), DEVCLANAME(dc)));

	buflen = strlen(dc->name) + 5;
	dev->nameunit = malloc(buflen, M_BUS, M_NOWAIT|M_ZERO);
	if (!dev->nameunit)
		return (ENOMEM);

	if ((error = devclass_alloc_unit(dc, &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);
}

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);
}

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, 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);
}

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);
}

device_t
device_add_child(device_t dev, const char *name, int unit)
{
	return (device_add_child_ordered(dev, 0, name, unit));
}

device_t
device_add_child_ordered(device_t dev, int order, const char *name, int unit)
{
	device_t child;
	device_t place;

	PDEBUG(("%s at %s with order %d 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);
}

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);
	device_set_desc(child, NULL);
	free(child, M_BUS);

	bus_data_generation_update();
	return (0);
}

/*
 * Find only devices attached to this bus.
 */
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);

	child = devclass_get_device(dc, unit);
	if (child && child->parent == dev)
		return (child);
	return (NULL);
}

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));
}

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));
}

static int
device_probe_child(device_t dev, device_t child)
{
	devclass_t dc;
	driverlink_t best = 0;
	driverlink_t dl;
	int result, pri = 0;
	int hasclass = (child->devclass != 0);

	dc = dev->devclass;
	if (!dc)
		panic("device_probe_child: parent device has no devclass");

	if (child->state == DS_ALIVE)
		return (0);

	for (dl = first_matching_driver(dc, child);
	     dl;
	     dl = next_matching_driver(dc, child, dl)) {
		PDEBUG(("Trying %s", DRIVERNAME(dl->driver)));
		device_set_driver(child, dl->driver);
		if (!hasclass)
			device_set_devclass(child, dl->driver->name);
		result = DEVICE_PROBE(child);
		if (!hasclass)
			device_set_devclass(child, 0);

		/*
		 * 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, 0);
			continue;
		}

		/*
		 * A priority lower than SUCCESS, remember the best matching
		 * driver. Initialise the value of pri for the first match.
		 */
		if (best == 0 || result > pri) {
			best = dl;
			pri = result;
			continue;
		}
	}

	/*
	 * If we found a driver, change state and initialise the devclass.
	 */
	if (best) {
		if (!child->devclass)
			device_set_devclass(child, best->driver->name);
		device_set_driver(child, best->driver);
		if (pri < 0) {
			/*
			 * A bit bogus. Call the probe method again to make
			 * sure that we have the right description.
			 */
			DEVICE_PROBE(child);
		}
		child->state = DS_ALIVE;

		bus_data_generation_update();
		return (0);
	}

	return (ENXIO);
}

device_t
device_get_parent(device_t dev)
{
	return (dev->parent);
}

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++;
	}

	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++;
	}

	*devlistp = list;
	*devcountp = count;

	return (0);
}

driver_t *
device_get_driver(device_t dev)
{
	return (dev->driver);
}

devclass_t
device_get_devclass(device_t dev)
{
	return (dev->devclass);
}

const char *
device_get_name(device_t dev)
{
	if (dev->devclass)
		return (devclass_get_name(dev->devclass));
	return (NULL);
}

const char *
device_get_nameunit(device_t dev)
{
	return (dev->nameunit);
}

int
device_get_unit(device_t dev)
{
	return (dev->unit);
}

const char *
device_get_desc(device_t dev)
{
	return (dev->desc);
}

u_int32_t
device_get_flags(device_t dev)
{
	return (dev->devflags);
}

int
device_print_prettyname(device_t dev)
{
	const char *name = device_get_name(dev);

	if (name == 0)
		return (printf("unknown: "));
	return (printf("%s%d: ", name, device_get_unit(dev)));
}

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);
}

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();
}

void
device_set_desc(device_t dev, const char* desc)
{
	device_set_desc_internal(dev, desc, FALSE);
}

void
device_set_desc_copy(device_t dev, const char* desc)
{
	device_set_desc_internal(dev, desc, TRUE);
}

void
device_set_flags(device_t dev, u_int32_t flags)
{
	dev->devflags = flags;
}

void *
device_get_softc(device_t dev)
{
	return (dev->softc);
}

void
device_set_softc(device_t dev, void *softc)
{
	if (dev->softc && !(dev->flags & DF_EXTERNALSOFTC))
		free(dev->softc, M_BUS);
	dev->softc = softc;
	if (dev->softc)
		dev->flags |= DF_EXTERNALSOFTC;
	else
		dev->flags &= ~DF_EXTERNALSOFTC;
}

void *
device_get_ivars(device_t dev)
{
	return (dev->ivars);
}

void
device_set_ivars(device_t dev, void * ivars)
{
	if (!dev)
		return;

	dev->ivars = ivars;

	return;
}

device_state_t
device_get_state(device_t dev)
{
	return (dev->state);
}

void
device_enable(device_t dev)
{
	dev->flags |= DF_ENABLED;
}

void
device_disable(device_t dev)
{
	dev->flags &= ~DF_ENABLED;
}

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;
}

void
device_unbusy(device_t dev)
{
	if (dev->state != DS_BUSY)
		panic("device_unbusy: called for non-busy device");
	dev->busy--;
	if (dev->busy == 0) {
		if (dev->parent)
			device_unbusy(dev->parent);
		dev->state = DS_ATTACHED;
	}
}

void
device_quiet(device_t dev)
{
	dev->flags |= DF_QUIET;
}

void
device_verbose(device_t dev)
{
	dev->flags &= ~DF_QUIET;
}

int
device_is_quiet(device_t dev)
{
	return ((dev->flags & DF_QUIET) != 0);
}

int
device_is_enabled(device_t dev)
{
	return ((dev->flags & DF_ENABLED) != 0);
}

int
device_is_alive(device_t dev)
{
	return (dev->state >= DS_ALIVE);
}

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, TRUE);
	if (!dc)
		return (ENOMEM);

	error = devclass_add_device(dc, dev);

	bus_data_generation_update();
	return (error);
}

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);
		dev->softc = NULL;
	}
	kobj_delete((kobj_t) dev, 0);
	dev->driver = driver;
	if (driver) {
		kobj_init((kobj_t) dev, (kobj_class_t) driver);
		if (!(dev->flags & DF_EXTERNALSOFTC)) {
			dev->softc = malloc(driver->size, M_BUS,
			    M_NOWAIT | M_ZERO);
			if (!dev->softc) {
				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);
}

int
device_probe_and_attach(device_t dev)
{
	device_t bus = dev->parent;
	int error = 0;
	int hasclass = (dev->devclass != 0);

	if (dev->state >= DS_ALIVE)
		return (0);

	if (dev->flags & DF_ENABLED) {
		error = device_probe_child(bus, dev);
		if (!error) {
			if (!device_is_quiet(dev))
				device_print_child(bus, dev);
			error = DEVICE_ATTACH(dev);
			if (!error)
				dev->state = DS_ATTACHED;
			else {
				printf("device_probe_and_attach: %s%d attach returned %d\n",
				    dev->driver->name, dev->unit, error);
				/* Unset the class; set in device_probe_child */
				if (!hasclass)
					device_set_devclass(dev, 0);
				device_set_driver(dev, NULL);
				dev->state = DS_NOTPRESENT;
			}
		} else {
			if (!(dev->flags & DF_DONENOMATCH)) {
				BUS_PROBE_NOMATCH(bus, dev);
				dev->flags |= DF_DONENOMATCH;
			}
		}
	} else {
		if (bootverbose) {
			device_print_prettyname(dev);
			printf("not probed (disabled)\n");
		}
	}

	return (error);
}

int
device_detach(device_t dev)
{
	int error;

	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);
	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);

	return (0);
}

int
device_shutdown(device_t dev)
{
	if (dev->state < DS_ATTACHED)
		return (0);
	return (DEVICE_SHUTDOWN(dev));
}

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.
 */

void
resource_list_init(struct resource_list *rl)
{
	SLIST_INIT(rl);
}

void
resource_list_free(struct resource_list *rl)
{
	struct resource_list_entry *rle;

	while ((rle = SLIST_FIRST(rl)) != NULL) {
		if (rle->res)
			panic("resource_list_free: resource entry is busy");
		SLIST_REMOVE_HEAD(rl, link);
		free(rle, M_BUS);
	}
}

void
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");
		SLIST_INSERT_HEAD(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;
}

struct resource_list_entry *
resource_list_find(struct resource_list *rl, int type, int rid)
{
	struct resource_list_entry *rle;

	SLIST_FOREACH(rle, rl, link) {
		if (rle->type == type && rle->rid == rid)
			return (rle);
	}
	return (NULL);
}

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");
		SLIST_REMOVE(rl, rle, resource_list_entry, link);
		free(rle, M_BUS);
	}
}

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 = 0;
	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 = max(count, rle->count);
		end = max(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);
}

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 = 0;
	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);
}

/*
 * Call DEVICE_IDENTIFY for each driver.
 */
int
bus_generic_probe(device_t dev)
{
	devclass_t dc = dev->devclass;
	driverlink_t dl;

	TAILQ_FOREACH(dl, &dc->drivers, link) {
		DEVICE_IDENTIFY(dl->driver, dev);
	}

	return (0);
}

int
bus_generic_attach(device_t dev)
{
	device_t child;

	TAILQ_FOREACH(child, &dev->children, link) {
		device_probe_and_attach(child);
	}

	return (0);
}

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);
}

int
bus_generic_shutdown(device_t dev)
{
	device_t child;

	TAILQ_FOREACH(child, &dev->children, link) {
		device_shutdown(child);
	}

	return (0);
}

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);
}

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);
}

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);
}

int
bus_print_child_footer (device_t dev, device_t child)
{
	return (printf(" on %s\n", device_get_nameunit(dev)));
}

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);
}

int
bus_generic_read_ivar(device_t dev, device_t child, int index,
    uintptr_t * result)
{
	return (ENOENT);
}

int
bus_generic_write_ivar(device_t dev, device_t child, int index,
    uintptr_t value)
{
	return (ENOENT);
}

struct resource_list *
bus_generic_get_resource_list (device_t dev, device_t child)
{
	return (NULL);
}

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)
			device_probe_and_attach(child);
	}
}

int
bus_generic_setup_intr(device_t dev, device_t child, struct resource *irq,
    int flags, 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,
		    intr, arg, cookiep));
	return (EINVAL);
}

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);
}

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);
}

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);
}

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);
}

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);
}

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);
}

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);
}

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;
}

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));
}

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));
}

/*
 * 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.
 */
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 == 0)
		return (0);
	return (BUS_ALLOC_RESOURCE(dev->parent, dev, type, rid, start, end,
	    count, flags));
}

int
bus_activate_resource(device_t dev, int type, int rid, struct resource *r)
{
	if (dev->parent == 0)
		return (EINVAL);
	return (BUS_ACTIVATE_RESOURCE(dev->parent, dev, type, rid, r));
}

int
bus_deactivate_resource(device_t dev, int type, int rid, struct resource *r)
{
	if (dev->parent == 0)
		return (EINVAL);
	return (BUS_DEACTIVATE_RESOURCE(dev->parent, dev, type, rid, r));
}

int
bus_release_resource(device_t dev, int type, int rid, struct resource *r)
{
	if (dev->parent == 0)
		return (EINVAL);
	return (BUS_RELEASE_RESOURCE(dev->parent, dev, type, rid, r));
}

int
bus_setup_intr(device_t dev, struct resource *r, int flags,
    driver_intr_t handler, void *arg, void **cookiep)
{
	if (dev->parent == 0)
		return (EINVAL);
	return (BUS_SETUP_INTR(dev->parent, dev, r, flags,
	    handler, arg, cookiep));
}

int
bus_teardown_intr(device_t dev, struct resource *r, void *cookie)
{
	if (dev->parent == 0)
		return (EINVAL);
	return (BUS_TEARDOWN_INTR(dev->parent, dev, r, cookie));
}

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);
}

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));
}

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);
}

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);
}

void
bus_delete_resource(device_t dev, int type, int rid)
{
	BUS_DELETE_RESOURCE(device_get_parent(dev), dev, type, rid);
}

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, driver_intr_t *intr, void *arg,
    void **cookiep)
{
	/*
	 * If an interrupt mapping gets to here something bad has happened.
	 */
	panic("root_setup_intr");
}

static kobj_method_t root_methods[] = {
	/* Device interface */
	KOBJMETHOD(device_shutdown,	bus_generic_shutdown),
	KOBJMETHOD(device_suspend,	bus_generic_suspend),
	KOBJMETHOD(device_resume,	bus_generic_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),

	{ 0, 0 }
};

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", FALSE);
		return (0);

	case MOD_SHUTDOWN:
		device_shutdown(root_bus);
		return (0);
	}

	return (0);
}

static moduledata_t root_bus_mod = {
	"rootbus",
	root_bus_module_handler,
	0
};
DECLARE_MODULE(rootbus, root_bus_mod, SI_SUB_DRIVERS, SI_ORDER_FIRST);

void
root_bus_configure(void)
{
	device_t dev;

	PDEBUG(("."));

	TAILQ_FOREACH(dev, &root_bus->children, link) {
		device_probe_and_attach(dev);
	}
}

int
driver_module_handler(module_t mod, int what, void *arg)
{
	int error, i;
	struct driver_module_data *dmd;
	devclass_t bus_devclass;

	dmd = (struct driver_module_data *)arg;
	bus_devclass = devclass_find_internal(dmd->dmd_busname, TRUE);
	error = 0;

	switch (what) {
	case MOD_LOAD:
		if (dmd->dmd_chainevh)
			error = dmd->dmd_chainevh(mod,what,dmd->dmd_chainarg);

		for (i = 0; !error && i < dmd->dmd_ndrivers; i++) {
			PDEBUG(("Loading module: driver %s on bus %s",
			    DRIVERNAME(dmd->dmd_drivers[i]), dmd->dmd_busname));
			error = devclass_add_driver(bus_devclass,
			    dmd->dmd_drivers[i]);
		}
		if (error)
			break;

		/*
		 * The drivers loaded in this way are assumed to all
		 * implement the same devclass.
		 */
		*dmd->dmd_devclass =
		    devclass_find_internal(dmd->dmd_drivers[0]->name, TRUE);
		break;

	case MOD_UNLOAD:
		for (i = 0; !error && i < dmd->dmd_ndrivers; i++) {
			PDEBUG(("Unloading module: driver %s from bus %s",
			    DRIVERNAME(dmd->dmd_drivers[i]),
			    dmd->dmd_busname));
			error = devclass_delete_driver(bus_devclass,
			    dmd->dmd_drivers[i]);
		}

		if (!error && dmd->dmd_chainevh)
			error = dmd->dmd_chainevh(mod,what,dmd->dmd_chainarg);
		break;
	}

	return (error);
}

#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,%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->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 = %d\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

/*
 * 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.
 */
SYSCTL_NODE(_hw, OID_AUTO, bus, CTLFLAG_RW, NULL, NULL);

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.
	 */
	udev.dv_handle = (uintptr_t)dev;
	udev.dv_parent = (uintptr_t)dev->parent;
	if (dev->nameunit == NULL) {
		udev.dv_name[0] = 0;
	} else {
		snprintf(udev.dv_name, 32, "%s", dev->nameunit);
	}
	if (dev->desc == NULL) {
		udev.dv_desc[0] = 0;
	} else {
		snprintf(udev.dv_desc, 32, "%s", dev->desc);
	}
	if ((dev->driver == NULL) || (dev->driver->name == NULL)) {
		udev.dv_drivername[0] = 0;
	} else {
		snprintf(udev.dv_drivername, 32, "%s", dev->driver->name);
	}
	error = SYSCTL_OUT(req, &udev, sizeof(udev));
	return (error);
}

SYSCTL_NODE(_hw_bus, OID_AUTO, devices, CTLFLAG_RD, sysctl_devices,
    "system device tree");

/*
 * Sysctl interface for scanning the resource lists.
 *
 * We take two input parameters; the index into the list of resource
 * managers, and the resource offset into the list.
 */
static int
sysctl_rman(SYSCTL_HANDLER_ARGS)
{
	int			*name = (int *)arg1;
	u_int			namelen = arg2;
	int			rman_idx, res_idx;
	struct rman		*rm;
	struct resource		*res;
	struct u_rman		urm;
	struct u_resource	ures;
	int			error;

	if (namelen != 3)
		return (EINVAL);

	if (bus_data_generation_check(name[0]))
		return (EINVAL);
	rman_idx = name[1];
	res_idx = name[2];

	/*
	 * Find the indexed resource manager
	 */
	TAILQ_FOREACH(rm, &rman_head, rm_link) {
		if (rman_idx-- == 0)
			break;
	}
	if (rm == NULL)
		return (ENOENT);

	/*
	 * If the resource index is -1, we want details on the
	 * resource manager.
	 */
	if (res_idx == -1) {
		urm.rm_handle = (uintptr_t)rm;
		snprintf(urm.rm_descr, RM_TEXTLEN, "%s", rm->rm_descr);
		urm.rm_descr[RM_TEXTLEN - 1] = '\0';
		urm.rm_start = rm->rm_start;
		urm.rm_size = rm->rm_end - rm->rm_start + 1;
		urm.rm_type = rm->rm_type;

		error = SYSCTL_OUT(req, &urm, sizeof(urm));
		return (error);
	}

	/*
	 * Find the indexed resource and return it.
	 */
	TAILQ_FOREACH(res, &rm->rm_list, r_link) {
		if (res_idx-- == 0) {
			ures.r_handle = (uintptr_t)res;
			ures.r_parent = (uintptr_t)res->r_rm;
			ures.r_device = (uintptr_t)res->r_dev;
			if (res->r_dev != NULL) {
				if (device_get_name(res->r_dev) != NULL) {
					snprintf(ures.r_devname, RM_TEXTLEN,
					    "%s%d",
					    device_get_name(res->r_dev),
					    device_get_unit(res->r_dev));
				} else {
					snprintf(ures.r_devname, RM_TEXTLEN,
					    "nomatch");
				}
			} else {
				ures.r_devname[0] = 0;
			}
			ures.r_start = res->r_start;
			ures.r_size = res->r_end - res->r_start + 1;
			ures.r_flags = res->r_flags;

			error = SYSCTL_OUT(req, &ures, sizeof(ures));
			return (error);
		}
	}
	return (ENOENT);
}

SYSCTL_NODE(_hw_bus, OID_AUTO, rman, CTLFLAG_RD, sysctl_rman,
    "kernel resource manager");

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++;
}