xref: /src/sys/kern/subr_autoconf.c

/* $NetBSD: subr_autoconf.c,v 1.62.6.1 2002/03/22 18:29:52 eeh Exp $ */

/*
 * Copyright (c) 1996, 2000 Christopher G. Demetriou
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *          This product includes software developed for the
 *          NetBSD Project.  See http://www.netbsd.org/ for
 *          information about NetBSD.
 * 4. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 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.
 *
 * --(license Id: LICENSE.proto,v 1.1 2000/06/13 21:40:26 cgd Exp )--
 */

/*
 * Copyright (c) 1992, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * This software was developed by the Computer Systems Engineering group
 * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
 * contributed to Berkeley.
 *
 * All advertising materials mentioning features or use of this software
 * must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Lawrence Berkeley Laboratories.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
 *
 * from: Header: subr_autoconf.c,v 1.12 93/02/01 19:31:48 torek Exp  (LBL)
 *
 *	@(#)subr_autoconf.c	8.3 (Berkeley) 5/17/94
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: subr_autoconf.c,v 1.62.6.1 2002/03/22 18:29:52 eeh Exp $");

#include "opt_ddb.h"

#include <sys/param.h>
#include <sys/device.h>
#include <sys/malloc.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/errno.h>
#include <sys/proc.h>
#include <sys/properties.h>
#include <machine/limits.h>

#include "opt_userconf.h"
#ifdef USERCONF
#include <sys/userconf.h>
#include <sys/reboot.h>
#endif

/*
 * Autoconfiguration subroutines.
 */

static struct device *dev_create(struct device *, ssize_t, int);

/*
 * ioconf.c exports exactly two names: cfdata and cfroots.  All system
 * devices and drivers are found via these tables.
 */
extern struct cfdata cfdata[];
extern short cfroots[];

#define	ROOT ((struct device *)NULL)

struct matchinfo {
	cfmatch_t fn;
	struct	device *parent;
	void	*aux;
	struct	cfdata *match;
	int	pri;
};

static char *number(char *, int);
static void mapply(struct matchinfo *, struct cfdata *, struct device *);
static void locset(struct device *, struct cfdata *);
static void locrm(struct device *, struct cfdata *);

struct deferred_config {
	TAILQ_ENTRY(deferred_config) dc_queue;
	struct device *dc_dev;
	void (*dc_func)(struct device *);
};

TAILQ_HEAD(deferred_config_head, deferred_config);

struct deferred_config_head deferred_config_queue;
struct deferred_config_head interrupt_config_queue;

static void config_process_deferred(struct deferred_config_head *,
	struct device *);

/* list of all devices */
struct devicelist alldevs;

/* list of all events */
struct evcntlist allevents = TAILQ_HEAD_INITIALIZER(allevents);

__volatile int config_pending;		/* semaphore for mountroot */

/* device properties database */
static propdb_t devpropdb;

/*
 * Configure the system's hardware.
 */
void
configure(void)
{

	TAILQ_INIT(&deferred_config_queue);
	TAILQ_INIT(&interrupt_config_queue);
	TAILQ_INIT(&alldevs);

	devpropdb = propdb_create("devprop");

#ifdef USERCONF
	if (boothowto & RB_USERCONF)
		user_config();
#endif

	/*
	 * Do the machine-dependent portion of autoconfiguration.  This
	 * sets the configuration machinery here in motion by "finding"
	 * the root bus.  When this function returns, we expect interrupts
	 * to be enabled.
	 */
	cpu_configure();

	/*
	 * Now that we've found all the hardware, start the real time
	 * and statistics clocks.
	 */
	initclocks();

	cold = 0;	/* clocks are running, we're warm now! */

	/*
	 * Now callback to finish configuration for devices which want
	 * to do this once interrupts are enabled.
	 */
	config_process_deferred(&interrupt_config_queue, NULL);
}

/*
 * Set locators as properties on device node.
 */
static void
locset(struct device *d, struct cfdata *cf)
{
	int i;
	int type = PROP_CONST|PROP_INT;
	char buf[32];

	for (i=0; cf->cf_locnames[i]; i++) {
		sprintf(buf, "loc-%s", cf->cf_locnames[i]);
		dev_setprop(d, buf, &cf->cf_loc[i],
			    sizeof(int), type, (!cold));
	}
}

/*
 * Remove locator properties from device node.
 */
static void
locrm(struct device *d, struct cfdata *cf)
{
	int i;
	char buf[32];

	for (i=0; cf->cf_locnames[i]; i++) {
		sprintf(buf, "loc-%s", cf->cf_locnames[i]);
		dev_delprop(d, buf);
	}
}

/*
 * Apply the matching function and choose the best.  This is used
 * a few times and we want to keep the code small.
 */
static void
mapply(struct matchinfo *m, struct cfdata *cf, struct device *child)
{
	int pri;
	void *aux = m->aux;

	if ((ssize_t)cf->cf_attach->ca_devsize < 0) {
		/* New-style device driver */
		if (!child)
			panic("mapply: no device for new-style driver\n");
		locset(child, cf);
		child->dv_private = aux;
		aux = child;
	}
	if (m->fn != NULL)
		/* Someday the submatch function should use properties too. */
		pri = (*m->fn)(m->parent, cf, m->aux);
	else {
	        if (cf->cf_attach->ca_match == NULL) {
			panic("mapply: no match function for '%s' device\n",
			    cf->cf_driver->cd_name);
		}
		pri = (*cf->cf_attach->ca_match)(m->parent, cf, aux);
	}
	if (pri > m->pri) {
		m->match = cf;
		m->pri = pri;
	}
	if (child) {
		locrm(child, cf);
		child->dv_private = NULL;
	}
}

/*
 * Iterate over all potential children of some device, calling the given
 * function (default being the child's match function) for each one.
 * Nonzero returns are matches; the highest value returned is considered
 * the best match.  Return the `found child' if we got a match, or NULL
 * otherwise.  The `aux' pointer is simply passed on through.
 *
 * Note that this function is designed so that it can be used to apply
 * an arbitrary function to all potential children (its return value
 * can be ignored).
 */
struct cfdata *
config_search_ad(cfmatch_t fn, struct device *parent, void *aux,
		 struct device *child)
{
	struct cfdata *cf;
	short *p;
	struct matchinfo m;

	m.fn = fn;
	m.parent = parent;
	m.aux = aux;
	m.match = NULL;
	m.pri = 0;

	for (cf = cfdata; cf->cf_driver; cf++) {
		/*
		 * Skip cf if no longer eligible, otherwise scan through
		 * parents for one matching `parent', and try match function.
		 */
		if (cf->cf_fstate == FSTATE_FOUND)
			continue;
		for (p = cf->cf_parents; *p >= 0; p++)
			if (parent->dv_cfdata == &cfdata[*p])
				mapply(&m, cf, child);
	}
	return (m.match);
}

/*
 * Find the given root device.
 * This is much like config_search, but there is no parent.
 */
struct cfdata *
config_rootsearch_ad(cfmatch_t fn, const char *rootname, void *aux,
		     struct device *root)
{
	struct cfdata *cf;
	short *p;
	struct matchinfo m;

	m.fn = fn;
	m.parent = ROOT;
	m.aux = aux;
	m.match = NULL;
	m.pri = 0;
	/*
	 * Look at root entries for matching name.  We do not bother
	 * with found-state here since only one root should ever be
	 * searched (and it must be done first).
	 */
	for (p = cfroots; *p >= 0; p++) {
		cf = &cfdata[*p];
		if (strcmp(cf->cf_driver->cd_name, rootname) == 0)
			mapply(&m, cf, root);
	}
	return (m.match);
}

static const char *msgs[3] = { "", " not configured\n", " unsupported\n" };

/*
 * The given `aux' argument describes a device that has been found
 * on the given parent, but not necessarily configured.  Locate the
 * configuration data for that device (using the submatch function
 * provided, or using candidates' cd_match configuration driver
 * functions) and attach it, and return true.  If the device was
 * not configured, call the given `print' function and return 0.
 */
struct device *
config_found_sad(struct device *parent, void *aux, cfprint_t print,
    cfmatch_t submatch, struct device *d)
{
	struct cfdata *cf;

	/*
	 * Creating the dummy device here is really optional.  But
	 * it allows old-style bus drivers to attach new-style children.
	 */
	if (!d) d = dev_create(ROOT, 0, cold ? M_NOWAIT : M_WAITOK);
	if ((cf = config_search_ad(submatch, parent, aux, d)) != NULL)
		return (config_attach_ad(parent, cf, aux, print, d));
	if (print)
		printf("%s", msgs[(*print)(aux, parent->dv_xname)]);
	return (NULL);
}

/*
 * As above, but for root devices.
 */
struct device *
config_rootfound(const char *rootname, void *aux)
{
	struct cfdata *cf;
	struct device *root;

	root = dev_create(ROOT, 0, cold ? M_NOWAIT : M_WAITOK);
	if ((cf = config_rootsearch_ad((cfmatch_t)NULL, rootname, aux, root)) != NULL)
		return (config_attach_ad(ROOT, cf, aux, (cfprint_t)NULL, root));
	printf("root device %s not configured\n", rootname);
	return (NULL);
}

/* just like sprintf(buf, "%d") except that it works from the end */
static char *
number(char *ep, int n)
{

	*--ep = 0;
	while (n >= 10) {
		*--ep = (n % 10) + '0';
		n /= 10;
	}
	*--ep = n + '0';
	return (ep);
}

/*
 * Allocate an empty device node.  If `parent' is provided then the
 * new node is attached to the tree under `parent'.  If `size'
 * is provided, then the new device node is allocated to be that
 * size.
 */
static struct device *
dev_create(struct device *parent, ssize_t size, int wait) {
	struct device * dev;

	/* get memory for all device vars */
	if (size == 0)
		size = sizeof(struct device);
	dev = (struct device *)malloc(size, M_DEVBUF, wait);
	if (!dev)
	    panic("dev_create: memory allocation for device failed");
	memset(dev, 0, size);
	TAILQ_INSERT_TAIL(&alldevs, dev, dv_list);	/* link up */
	dev->dv_class = DV_EMPTY;
	if (parent)
		dev->dv_parent = parent;
	return (dev);
}

/*
 * Expand the size of the cd_devs array if necessary.
 */
void
config_makeroom(int n, struct cfdriver *cd)
{
	int old, new;
	void **nsp;

	if (n < cd->cd_ndevs)
		return;

	/*
	 * Need to expand the array.
	 */
	old = cd->cd_ndevs;
	if (old == 0)
		new = MINALLOCSIZE / sizeof(void *);
	else
		new = old * 2;
	while (new <= n)
		new *= 2;
	cd->cd_ndevs = new;
	nsp = malloc(new * sizeof(void *), M_DEVBUF,
	    cold ? M_NOWAIT : M_WAITOK);
	if (nsp == NULL)
		panic("config_attach: %sing dev array",
		    old != 0 ? "expand" : "creat");
	memset(nsp + old, 0, (new - old) * sizeof(void *));
	if (old != 0) {
		memcpy(nsp, cd->cd_devs, old * sizeof(void *));
		free(cd->cd_devs, M_DEVBUF);
	}
	cd->cd_devs = nsp;
}

/*
 * Attach a found device.  Allocates memory for device variables.
 */
struct device *
config_attach_ad(struct device *parent, struct cfdata *cf, void *aux,
	cfprint_t print, struct device *propdev)
{
	struct device *dev;
	struct cfdriver *cd;
	struct cfattach *ca;
	size_t lname, lunit;
	ssize_t softsize;
	const char *xunit;
	int myunit;
	char num[10];

	cd = cf->cf_driver;
	ca = cf->cf_attach;
	softsize = ca->ca_devsize;

#ifndef __BROKEN_CONFIG_UNIT_USAGE
	if (cf->cf_fstate == FSTATE_STAR) {
		for (myunit = cf->cf_unit; myunit < cd->cd_ndevs; myunit++)
			if (cd->cd_devs[myunit] == NULL)
				break;
		/*
		 * myunit is now the unit of the first NULL device pointer,
		 * or max(cd->cd_ndevs,cf->cf_unit).
		 */
	} else {
		myunit = cf->cf_unit;
#else /* __BROKEN_CONFIG_UNIT_USAGE */
	myunit = cf->cf_unit;
	if (cf->cf_fstate == FSTATE_STAR)
		cf->cf_unit++;
	else {
#endif /* __BROKEN_CONFIG_UNIT_USAGE */
		KASSERT(cf->cf_fstate == FSTATE_NOTFOUND);
		cf->cf_fstate = FSTATE_FOUND;
	}

	/* compute length of name and decimal expansion of unit number */
	lname = strlen(cd->cd_name);
	xunit = number(&num[sizeof(num)], myunit);
	lunit = &num[sizeof(num)] - xunit;
	if (lname + lunit >= sizeof(dev->dv_xname))
		panic("config_attach: device name too long");

	/* get memory for all device vars */
	if (softsize < 0) {
		/* New-style device */
		if (propdev) {
			/* Great, we can use the propdev. */
			dev = propdev;
		} else {
			dev = dev_create(parent, 0, cold ? M_NOWAIT : M_WAITOK);
			if (!dev)
				panic("config_attach: memory allocation for device failed");
		}
		if (softsize < 0) softsize = -softsize;
		if (softsize < sizeof(struct device)) panic("config_attach");
		dev->dv_private = malloc(softsize, M_DEVBUF,
					 cold ? M_NOWAIT : M_WAITOK);
		if (!dev->dv_private)
			panic("config_attach: memory allocation for device softc failed");
		memset(dev->dv_private, 0, softsize);
		dev->dv_flags |= DVF_SOFTC;
	} else {
		dev = (struct device *)malloc(softsize, M_DEVBUF,
					      cold ? M_NOWAIT : M_WAITOK);
		if (!dev)
			panic("config_attach: memory allocation for device softc failed");
		memset(dev, 0, softsize);
		TAILQ_INSERT_TAIL(&alldevs, dev, dv_list);	/* link up */
		dev->dv_private = dev;		/* Point private to ourself... */
	}
	dev->dv_class = cd->cd_class;
	dev->dv_cfdata = cf;
	dev->dv_unit = myunit;
	memcpy(dev->dv_xname, cd->cd_name, lname);
	memcpy(dev->dv_xname + lname, xunit, lunit);
	dev->dv_parent = parent;
	dev->dv_flags |= DVF_ACTIVE;	/* always initially active */
	if (propdev && propdev != dev) {
		/* Inherit (steal) properties from dummy device */
		dev_copyprops(propdev, dev, (!cold));
		dev_delprop(propdev, NULL);
		/* destroy propdev */
		config_detach(propdev, 0);
	}

	if (parent == ROOT)
		printf("%s (root)", dev->dv_xname);
	else {
		printf("%s at %s", dev->dv_xname, parent->dv_xname);
		if (print)
			(void) (*print)(aux, NULL);
	}

	/* put this device in the devices array */
	config_makeroom(dev->dv_unit, cd);
	if (cd->cd_devs[dev->dv_unit])
		panic("config_attach: duplicate %s", dev->dv_xname);
	cd->cd_devs[dev->dv_unit] = dev;

	/*
	 * Before attaching, clobber any unfound devices that are
	 * otherwise identical.
	 */
#ifdef __BROKEN_CONFIG_UNIT_USAGE
	/* bump the unit number on all starred cfdata for this device. */
#endif /* __BROKEN_CONFIG_UNIT_USAGE */
	for (cf = cfdata; cf->cf_driver; cf++)
		if (cf->cf_driver == cd && cf->cf_unit == dev->dv_unit) {
			if (cf->cf_fstate == FSTATE_NOTFOUND)
				cf->cf_fstate = FSTATE_FOUND;
#ifdef __BROKEN_CONFIG_UNIT_USAGE
			if (cf->cf_fstate == FSTATE_STAR)
				cf->cf_unit++;
#endif /* __BROKEN_CONFIG_UNIT_USAGE */
		}
#ifdef __HAVE_DEVICE_REGISTER
	device_register(dev, aux);
#endif
	(*ca->ca_attach)(parent, dev, aux);
	config_process_deferred(&deferred_config_queue, dev);
	return (dev);
}

/*
 * Detach a device.  Optionally forced (e.g. because of hardware
 * removal) and quiet.  Returns zero if successful, non-zero
 * (an error code) otherwise.
 *
 * Note that this code wants to be run from a process context, so
 * that the detach can sleep to allow processes which have a device
 * open to run and unwind their stacks.
 */
int
config_detach(struct device *dev, int flags)
{
	struct cfdata *cf;
	struct cfattach *ca;
	struct cfdriver *cd;
#ifdef DIAGNOSTIC
	struct device *d;
#endif
	int rv = 0, i;

	if (dev->dv_class == DV_EMPTY) {
		/*
		 * The device is a dummy that never fully attached.
		 * Simply remove it from the global list and free it.
		 */
		TAILQ_REMOVE(&alldevs, dev, dv_list);
		dev_delprop(dev, NULL);
		if (dev->dv_flags & DVF_SOFTC)
			/* Separately allocated softc */
			free(dev->dv_private, M_DEVBUF);
		free(dev, M_DEVBUF);
		return (0);
	}

	cf = dev->dv_cfdata;
#ifdef DIAGNOSTIC
	if (cf->cf_fstate != FSTATE_FOUND && cf->cf_fstate != FSTATE_STAR)
		panic("config_detach: bad device fstate");
#endif
	ca = cf->cf_attach;
	cd = cf->cf_driver;

	/*
	 * Ensure the device is deactivated.  If the device doesn't
	 * have an activation entry point, we allow DVF_ACTIVE to
	 * remain set.  Otherwise, if DVF_ACTIVE is still set, the
	 * device is busy, and the detach fails.
	 */
	if (ca->ca_activate != NULL)
		rv = config_deactivate(dev);

	/*
	 * Try to detach the device.  If that's not possible, then
	 * we either panic() (for the forced but failed case), or
	 * return an error.
	 */
	if (rv == 0) {
		if (ca->ca_detach != NULL)
			rv = (*ca->ca_detach)(dev, flags);
		else
			rv = EOPNOTSUPP;
	}
	if (rv != 0) {
		if ((flags & DETACH_FORCE) == 0)
			return (rv);
		else
			panic("config_detach: forced detach of %s failed (%d)",
			      dev->dv_xname, rv);
	}

	/*
	 * The device has now been successfully detached.
	 */

#ifdef DIAGNOSTIC
	/*
	 * Sanity: If you're successfully detached, you should have no
	 * children.  (Note that because children must be attached
	 * after parents, we only need to search the latter part of
	 * the list.)
	 */
	for (d = TAILQ_NEXT(dev, dv_list); d != NULL;
	     d = TAILQ_NEXT(d, dv_list)) {
		if (d->dv_parent == dev) {
			printf("config_detach: detached device %s"
			       " has children %s\n", dev->dv_xname, d->dv_xname);
			panic("config_detach");
		}
	}
#endif

	/*
	 * Mark cfdata to show that the unit can be reused, if possible.
	 */
#ifdef __BROKEN_CONFIG_UNIT_USAGE
	/*
	 * Note that we can only re-use a starred unit number if the unit
	 * being detached had the last assigned unit number.
	 */
#endif /* __BROKEN_CONFIG_UNIT_USAGE */
	for (cf = cfdata; cf->cf_driver; cf++) {
		if (cf->cf_driver == cd) {
			if (cf->cf_fstate == FSTATE_FOUND &&
			    cf->cf_unit == dev->dv_unit)
				cf->cf_fstate = FSTATE_NOTFOUND;
#ifdef __BROKEN_CONFIG_UNIT_USAGE
			if (cf->cf_fstate == FSTATE_STAR &&
			    cf->cf_unit == dev->dv_unit + 1)
				cf->cf_unit--;
#endif /* __BROKEN_CONFIG_UNIT_USAGE */
		}
	}

	/*
	 * Unlink from device list.
	 */
	TAILQ_REMOVE(&alldevs, dev, dv_list);

	/*
	 * Remove from cfdriver's array, tell the world, and free softc.
	 */
	if (cd) {
		cd->cd_devs[dev->dv_unit] = NULL;
		if ((flags & DETACH_QUIET) == 0)
			printf("%s detached\n", dev->dv_xname);
	}
	dev_delprop(dev, NULL);
	if (dev->dv_flags & DVF_SOFTC)
		/* Separately allocated softc */
		free(dev->dv_private, M_DEVBUF);
	free(dev, M_DEVBUF);

	/*
	 * If the device now has no units in use, deallocate its softc array.
	 */
	for (i = 0; i < cd->cd_ndevs; i++)
		if (cd->cd_devs[i] != NULL)
			break;
	if (i == cd->cd_ndevs) {		/* nothing found; deallocate */
		free(cd->cd_devs, M_DEVBUF);
		cd->cd_devs = NULL;
		cd->cd_ndevs = 0;
	}

	/*
	 * Return success.
	 */
	return (0);
}

int
config_activate(struct device *dev)
{
	struct cfattach *ca = dev->dv_cfdata->cf_attach;
	int rv = 0, oflags = dev->dv_flags;

	if (ca->ca_activate == NULL)
		return (EOPNOTSUPP);

	if ((dev->dv_flags & DVF_ACTIVE) == 0) {
		dev->dv_flags |= DVF_ACTIVE;
		rv = (*ca->ca_activate)(dev, DVACT_ACTIVATE);
		if (rv)
			dev->dv_flags = oflags;
	}
	return (rv);
}

int
config_deactivate(struct device *dev)
{
	struct cfattach *ca = dev->dv_cfdata->cf_attach;
	int rv = 0, oflags = dev->dv_flags;

	if (ca->ca_activate == NULL)
		return (EOPNOTSUPP);

	if (dev->dv_flags & DVF_ACTIVE) {
		dev->dv_flags &= ~DVF_ACTIVE;
		rv = (*ca->ca_activate)(dev, DVACT_DEACTIVATE);
		if (rv)
			dev->dv_flags = oflags;
	}
	return (rv);
}

/*
 * Defer the configuration of the specified device until all
 * of its parent's devices have been attached.
 */
void
config_defer(struct device *dev, void (*func)(struct device *))
{
	struct deferred_config *dc;

	if (dev->dv_parent == NULL)
		panic("config_defer: can't defer config of a root device");

#ifdef DIAGNOSTIC
	for (dc = TAILQ_FIRST(&deferred_config_queue); dc != NULL;
	     dc = TAILQ_NEXT(dc, dc_queue)) {
		if (dc->dc_dev == dev)
			panic("config_defer: deferred twice");
	}
#endif

	dc = malloc(sizeof(*dc), M_DEVBUF, cold ? M_NOWAIT : M_WAITOK);
	if (dc == NULL)
		panic("config_defer: unable to allocate callback");

	dc->dc_dev = dev;
	dc->dc_func = func;
	TAILQ_INSERT_TAIL(&deferred_config_queue, dc, dc_queue);
	config_pending_incr();
}

/*
 * Defer some autoconfiguration for a device until after interrupts
 * are enabled.
 */
void
config_interrupts(struct device *dev, void (*func)(struct device *))
{
	struct deferred_config *dc;

	/*
	 * If interrupts are enabled, callback now.
	 */
	if (cold == 0) {
		(*func)(dev);
		return;
	}

#ifdef DIAGNOSTIC
	for (dc = TAILQ_FIRST(&interrupt_config_queue); dc != NULL;
	     dc = TAILQ_NEXT(dc, dc_queue)) {
		if (dc->dc_dev == dev)
			panic("config_interrupts: deferred twice");
	}
#endif

	dc = malloc(sizeof(*dc), M_DEVBUF, cold ? M_NOWAIT : M_WAITOK);
	if (dc == NULL)
		panic("config_interrupts: unable to allocate callback");

	dc->dc_dev = dev;
	dc->dc_func = func;
	TAILQ_INSERT_TAIL(&interrupt_config_queue, dc, dc_queue);
	config_pending_incr();
}

/*
 * Process a deferred configuration queue.
 */
static void
config_process_deferred(struct deferred_config_head *queue,
    struct device *parent)
{
	struct deferred_config *dc, *ndc;

	for (dc = TAILQ_FIRST(queue); dc != NULL; dc = ndc) {
		ndc = TAILQ_NEXT(dc, dc_queue);
		if (parent == NULL || dc->dc_dev->dv_parent == parent) {
			TAILQ_REMOVE(queue, dc, dc_queue);
			(*dc->dc_func)(dc->dc_dev);
			free(dc, M_DEVBUF);
			config_pending_decr();
		}
	}
}

/*
 * Manipulate the config_pending semaphore.
 */
void
config_pending_incr(void)
{

	config_pending++;
}

void
config_pending_decr(void)
{

#ifdef DIAGNOSTIC
	if (config_pending == 0)
		panic("config_pending_decr: config_pending == 0");
#endif
	config_pending--;
	if (config_pending == 0)
		wakeup((void *)&config_pending);
}

/*
 * Attach a statically-initialized event.  The type and string pointers
 * are already set up.
 */
void
evcnt_attach_static(struct evcnt *ev)
{
	int len;

	len = strlen(ev->ev_group);
#ifdef DIAGNOSTIC
	if (len >= EVCNT_STRING_MAX)		/* ..._MAX includes NUL */
		panic("evcnt_attach_static: group length (%s)", ev->ev_group);
#endif
	ev->ev_grouplen = len;

	len = strlen(ev->ev_name);
#ifdef DIAGNOSTIC
	if (len >= EVCNT_STRING_MAX)		/* ..._MAX includes NUL */
		panic("evcnt_attach_static: name length (%s)", ev->ev_name);
#endif
	ev->ev_namelen = len;

	TAILQ_INSERT_TAIL(&allevents, ev, ev_list);
}

/*
 * Attach a dynamically-initialized event.  Zero it, set up the type
 * and string pointers and then act like it was statically initialized.
 */
void
evcnt_attach_dynamic(struct evcnt *ev, int type, const struct evcnt *parent,
    const char *group, const char *name)
{

	memset(ev, 0, sizeof *ev);
	ev->ev_type = type;
	ev->ev_parent = parent;
	ev->ev_group = group;
	ev->ev_name = name;
	evcnt_attach_static(ev);
}

/*
 * Detach an event.
 */
void
evcnt_detach(struct evcnt *ev)
{

	TAILQ_REMOVE(&allevents, ev, ev_list);
}

/*
 * Device property management routines.
 */
#ifdef DEBUG
int devprop_debug = 0;
#endif

/*
 * Create a dummy device you can attach properties to.
 */
struct device *
dev_config_create(struct device *parent, int wait)
{
	struct device *dev;

	dev = dev_create(parent, 0, wait ? M_WAITOK : M_NOWAIT);
	return (dev);
}


int
dev_setprop(struct device *dev, const char *name, void *val,
			size_t len, int type, int wait)
{
#ifdef DEBUG
	if (devprop_debug)
		printf("dev_setprop(%p, %s, %p %s, %ld, %x, %d)\n",
		       dev, name, val, (PROP_TYPE(type) == PROP_STRING) ?
		       (char *)val : "", len, type, wait);
#endif

	return (prop_set(devpropdb, dev, name, val, len, type, wait));
}

size_t
dev_getprop(struct device *dev, const char *name, void *val,
			size_t len, int *type, int search)
{
	ssize_t rv;

#ifdef DEBUG
	if (devprop_debug) {
		printf("dev_getprop(%p, %s, %p, %ld, %p, %d)\n",
		       dev, name, val, len, type, search);
	}
#endif
	rv = prop_get(devpropdb, dev, name, val, len, type);
	if (rv == -1) {
		/* Not found -- try md_getprop */
		rv = dev_mdgetprop(dev->dv_parent, name, val,
			len, type);
	}
	if ((rv == -1) && search) {
		if (dev->dv_parent)
			/* Tail recursion -- there should be no stack growth. */
			return (dev_getprop(dev->dv_parent, name,
					    val, len, type, search));
	}
#ifdef DEBUG
	if (devprop_debug && (rv == -1)) {
		printf("%s no found\n", name);
	}
#endif
	return (rv);
}

int
dev_delprop(struct device *dev, const char *name)
{

#ifdef DEBUG_N
	if (devprop_debug)
		printf("dev_delprop(%p, %s, %x)\n", dev, name);
#endif
	return (prop_delete(devpropdb, dev, name));
}


int
dev_copyprops(struct device *src, struct device *dest, int wait)
{
	return (prop_copy(devpropdb, src, dest, wait));
}

#ifdef DDB
void
event_print(int full, void (*pr)(const char *, ...))
{
	struct evcnt *evp;

	TAILQ_FOREACH(evp, &allevents, ev_list) {
		if (evp->ev_count == 0 && !full)
			continue;

		(*pr)("evcnt type %d: %s %s = %lld\n", evp->ev_type,
		    evp->ev_group, evp->ev_name, evp->ev_count);
	}
}
#endif /* DDB */