FreeBSD/Linux Kernel Cross Reference
sys/kern/subr_autoconf.c

     /* $NetBSD: subr_autoconf.c,v 1.163.4.3 2010/11/20 17:41:27 riz 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. 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 1.163.4.3 2010/11/20 17:41:27 riz Exp $");
    
    #include "opt_ddb.h"
    #include "drvctl.h"
    
    #include <sys/param.h>
    #include <sys/device.h>
    #include <sys/disklabel.h>
    #include <sys/conf.h>
    #include <sys/kauth.h>
    #include <sys/malloc.h>
    #include <sys/kmem.h>
    #include <sys/systm.h>
    #include <sys/kernel.h>
    #include <sys/errno.h>
    #include <sys/proc.h>
    #include <sys/reboot.h>
    #include <sys/kthread.h>
    #include <sys/buf.h>
    #include <sys/dirent.h>
   #include <sys/vnode.h>
   #include <sys/mount.h>
   #include <sys/namei.h>
   #include <sys/unistd.h>
   #include <sys/fcntl.h>
   #include <sys/lockf.h>
   #include <sys/callout.h>
   #include <sys/mutex.h>
   #include <sys/condvar.h>
   #include <sys/devmon.h>
   #include <sys/cpu.h>
   
   #include <sys/disk.h>
   
   #include <machine/limits.h>
   
   #include "opt_userconf.h"
   #ifdef USERCONF
   #include <sys/userconf.h>
   #endif
   
   #ifdef __i386__
   #include "opt_splash.h"
   #if defined(SPLASHSCREEN) && defined(SPLASHSCREEN_PROGRESS)
   #include <dev/splash/splash.h>
   extern struct splash_progress *splash_progress_state;
   #endif
   #endif
   
   /*
    * Autoconfiguration subroutines.
    */
   
   typedef struct pmf_private {
           int             pp_nwait;
           int             pp_nlock;
           lwp_t           *pp_holder;
           kmutex_t        pp_mtx;
           kcondvar_t      pp_cv;
   } pmf_private_t;
   
   /*
    * ioconf.c exports exactly two names: cfdata and cfroots.  All system
    * devices and drivers are found via these tables.
    */
   extern struct cfdata cfdata[];
   extern const short cfroots[];
   
   /*
    * List of all cfdriver structures.  We use this to detect duplicates
    * when other cfdrivers are loaded.
    */
   struct cfdriverlist allcfdrivers = LIST_HEAD_INITIALIZER(&allcfdrivers);
   extern struct cfdriver * const cfdriver_list_initial[];
   
   /*
    * Initial list of cfattach's.
    */
   extern const struct cfattachinit cfattachinit[];
   
   /*
    * List of cfdata tables.  We always have one such list -- the one
    * built statically when the kernel was configured.
    */
   struct cftablelist allcftables = TAILQ_HEAD_INITIALIZER(allcftables);
   static struct cftable initcftable;
   
   #define ROOT ((device_t)NULL)
   
   struct matchinfo {
           cfsubmatch_t fn;
           struct  device *parent;
           const int *locs;
           void    *aux;
           struct  cfdata *match;
           int     pri;
   };
   
   static char *number(char *, int);
   static void mapply(struct matchinfo *, cfdata_t);
   static device_t config_devalloc(const device_t, const cfdata_t, const int *);
   static void config_devdealloc(device_t);
   static void config_makeroom(int, struct cfdriver *);
   static void config_devlink(device_t);
   static void config_devunlink(device_t);
   
   static void pmflock_debug(device_t, const char *, int);
   static void pmflock_debug_with_flags(device_t, const char *, int PMF_FN_PROTO);
   
   static device_t deviter_next1(deviter_t *);
   static void deviter_reinit(deviter_t *);
   
   struct deferred_config {
           TAILQ_ENTRY(deferred_config) dc_queue;
           device_t dc_dev;
           void (*dc_func)(device_t);
   };
   
   TAILQ_HEAD(deferred_config_head, deferred_config);
   
   struct deferred_config_head deferred_config_queue =
           TAILQ_HEAD_INITIALIZER(deferred_config_queue);
   struct deferred_config_head interrupt_config_queue =
           TAILQ_HEAD_INITIALIZER(interrupt_config_queue);
   int interrupt_config_threads = 8;
   
   static void config_process_deferred(struct deferred_config_head *, device_t);
   
   /* Hooks to finalize configuration once all real devices have been found. */
   struct finalize_hook {
           TAILQ_ENTRY(finalize_hook) f_list;
           int (*f_func)(device_t);
           device_t f_dev;
   };
   static TAILQ_HEAD(, finalize_hook) config_finalize_list =
           TAILQ_HEAD_INITIALIZER(config_finalize_list);
   static int config_finalize_done;
   
   /* list of all devices */
   struct devicelist alldevs = TAILQ_HEAD_INITIALIZER(alldevs);
   kcondvar_t alldevs_cv;
   kmutex_t alldevs_mtx;
   static int alldevs_nread = 0;
   static int alldevs_nwrite = 0;
   static lwp_t *alldevs_writer = NULL;
   
   static int config_pending;              /* semaphore for mountroot */
   static kmutex_t config_misc_lock;
   static kcondvar_t config_misc_cv;
   
   #define STREQ(s1, s2)                   \
           (*(s1) == *(s2) && strcmp((s1), (s2)) == 0)
   
   static int config_initialized;          /* config_init() has been called. */
   
   static int config_do_twiddle;
   
   struct vnode *
   opendisk(struct device *dv)
   {
           int bmajor, bminor;
           struct vnode *tmpvn;
           int error;
           dev_t dev;
           
           /*
            * Lookup major number for disk block device.
            */
           bmajor = devsw_name2blk(device_xname(dv), NULL, 0);
           if (bmajor == -1)
                   return NULL;
           
           bminor = minor(device_unit(dv));
           /*
            * Fake a temporary vnode for the disk, open it, and read
            * and hash the sectors.
            */
           dev = device_is_a(dv, "dk") ? makedev(bmajor, bminor) :
               MAKEDISKDEV(bmajor, bminor, RAW_PART);
           if (bdevvp(dev, &tmpvn))
                   panic("%s: can't alloc vnode for %s", __func__,
                       device_xname(dv));
           error = VOP_OPEN(tmpvn, FREAD, NOCRED);
           if (error) {
   #ifndef DEBUG
                   /*
                    * Ignore errors caused by missing device, partition,
                    * or medium.
                    */
                   if (error != ENXIO && error != ENODEV)
   #endif
                           printf("%s: can't open dev %s (%d)\n",
                               __func__, device_xname(dv), error);
                   vput(tmpvn);
                   return NULL;
           }
   
           return tmpvn;
   }
   
   int
   config_handle_wedges(struct device *dv, int par)
   {
           struct dkwedge_list wl;
           struct dkwedge_info *wi;
           struct vnode *vn;
           char diskname[16];
           int i, error;
   
           if ((vn = opendisk(dv)) == NULL)
                   return -1;
   
           wl.dkwl_bufsize = sizeof(*wi) * 16;
           wl.dkwl_buf = wi = malloc(wl.dkwl_bufsize, M_TEMP, M_WAITOK);
   
           error = VOP_IOCTL(vn, DIOCLWEDGES, &wl, FREAD, NOCRED);
           VOP_CLOSE(vn, FREAD, NOCRED);
           vput(vn);
           if (error) {
   #ifdef DEBUG_WEDGE
                   printf("%s: List wedges returned %d\n",
                       device_xname(dv), error);
   #endif
                   free(wi, M_TEMP);
                   return -1;
           }
   
   #ifdef DEBUG_WEDGE
           printf("%s: Returned %u(%u) wedges\n", device_xname(dv),
               wl.dkwl_nwedges, wl.dkwl_ncopied);
   #endif
           snprintf(diskname, sizeof(diskname), "%s%c", device_xname(dv),
               par + 'a');
   
           for (i = 0; i < wl.dkwl_ncopied; i++) {
   #ifdef DEBUG_WEDGE
                   printf("%s: Looking for %s in %s\n", 
                       device_xname(dv), diskname, wi[i].dkw_wname);
   #endif
                   if (strcmp(wi[i].dkw_wname, diskname) == 0)
                           break;
           }
   
           if (i == wl.dkwl_ncopied) {
   #ifdef DEBUG_WEDGE
                   printf("%s: Cannot find wedge with parent %s\n",
                       device_xname(dv), diskname);
   #endif
                   free(wi, M_TEMP);
                   return -1;
           }
   
   #ifdef DEBUG_WEDGE
           printf("%s: Setting boot wedge %s (%s) at %llu %llu\n", 
                   device_xname(dv), wi[i].dkw_devname, wi[i].dkw_wname,
                   (unsigned long long)wi[i].dkw_offset,
                   (unsigned long long)wi[i].dkw_size);
   #endif
           dkwedge_set_bootwedge(dv, wi[i].dkw_offset, wi[i].dkw_size);
           free(wi, M_TEMP);
           return 0;
   }
   
   /*
    * Initialize the autoconfiguration data structures.  Normally this
    * is done by configure(), but some platforms need to do this very
    * early (to e.g. initialize the console).
    */
   void
   config_init(void)
   {
           const struct cfattachinit *cfai;
           int i, j;
   
           if (config_initialized)
                   return;
   
           mutex_init(&alldevs_mtx, MUTEX_DEFAULT, IPL_NONE);
           cv_init(&alldevs_cv, "alldevs");
   
           mutex_init(&config_misc_lock, MUTEX_DEFAULT, IPL_NONE);
           cv_init(&config_misc_cv, "cfgmisc");
   
           /* allcfdrivers is statically initialized. */
           for (i = 0; cfdriver_list_initial[i] != NULL; i++) {
                   if (config_cfdriver_attach(cfdriver_list_initial[i]) != 0)
                           panic("configure: duplicate `%s' drivers",
                               cfdriver_list_initial[i]->cd_name);
           }
   
           for (cfai = &cfattachinit[0]; cfai->cfai_name != NULL; cfai++) {
                   for (j = 0; cfai->cfai_list[j] != NULL; j++) {
                           if (config_cfattach_attach(cfai->cfai_name,
                                                      cfai->cfai_list[j]) != 0)
                                   panic("configure: duplicate `%s' attachment "
                                       "of `%s' driver",
                                       cfai->cfai_list[j]->ca_name,
                                       cfai->cfai_name);
                   }
           }
   
           initcftable.ct_cfdata = cfdata;
           TAILQ_INSERT_TAIL(&allcftables, &initcftable, ct_list);
   
           config_initialized = 1;
   }
   
   void
   config_deferred(device_t dev)
   {
           config_process_deferred(&deferred_config_queue, dev);
           config_process_deferred(&interrupt_config_queue, dev);
   }
   
   static void
   config_interrupts_thread(void *cookie)
   {
           struct deferred_config *dc;
   
           while ((dc = TAILQ_FIRST(&interrupt_config_queue)) != NULL) {
                   TAILQ_REMOVE(&interrupt_config_queue, dc, dc_queue);
                   (*dc->dc_func)(dc->dc_dev);
                   kmem_free(dc, sizeof(*dc));
                   config_pending_decr();
           }
           kthread_exit(0);
   }
   
   /*
    * Configure the system's hardware.
    */
   void
   configure(void)
   {
           /* Initialize data structures. */
           config_init();
           pmf_init();
   #if NDRVCTL > 0
           drvctl_init();
   #endif
   
   #ifdef USERCONF
           if (boothowto & RB_USERCONF)
                   user_config();
   #endif
   
           if ((boothowto & (AB_SILENT|AB_VERBOSE)) == AB_SILENT) {
                   config_do_twiddle = 1;
                   printf_nolog("Detecting hardware...");
           }
   
           /*
            * 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();
   }
   
   void
   configure2(void)
   {
           CPU_INFO_ITERATOR cii;
           struct cpu_info *ci;
           int i, s;
   
           /*
            * 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! */
           s = splsched();
           curcpu()->ci_schedstate.spc_flags |= SPCF_RUNNING;
           splx(s);
   
           /* Boot the secondary processors. */
           for (CPU_INFO_FOREACH(cii, ci)) {
                   uvm_cpu_attach(ci);
           }
           mp_online = true;
   #if defined(MULTIPROCESSOR)
           cpu_boot_secondary_processors();
   #endif
   
           /* Setup the runqueues and scheduler. */
           runq_init();
           sched_init();
   
           /*
            * Create threads to call back and finish configuration for
            * devices that want interrupts enabled.
            */
           for (i = 0; i < interrupt_config_threads; i++) {
                   (void)kthread_create(PRI_NONE, 0, NULL,
                       config_interrupts_thread, NULL, NULL, "config");
           }
   
           /* Get the threads going and into any sleeps before continuing. */
           yield();
   }
   
   /*
    * Announce device attach/detach to userland listeners.
    */
   static void
   devmon_report_device(device_t dev, bool isattach)
   {
   #if NDRVCTL > 0
           prop_dictionary_t ev;
           const char *parent;
           const char *what;
           device_t pdev = device_parent(dev);
   
           ev = prop_dictionary_create();
           if (ev == NULL)
                   return;
   
           what = (isattach ? "device-attach" : "device-detach");
           parent = (pdev == NULL ? "root" : device_xname(pdev));
           if (!prop_dictionary_set_cstring(ev, "device", device_xname(dev)) ||
               !prop_dictionary_set_cstring(ev, "parent", parent)) {
                   prop_object_release(ev);
                   return;
           }
   
           devmon_insert(what, ev);
   #endif
   }
   
   /*
    * Add a cfdriver to the system.
    */
   int
   config_cfdriver_attach(struct cfdriver *cd)
   {
           struct cfdriver *lcd;
   
           /* Make sure this driver isn't already in the system. */
           LIST_FOREACH(lcd, &allcfdrivers, cd_list) {
                   if (STREQ(lcd->cd_name, cd->cd_name))
                           return (EEXIST);
           }
   
           LIST_INIT(&cd->cd_attach);
           LIST_INSERT_HEAD(&allcfdrivers, cd, cd_list);
   
           return (0);
   }
   
   /*
    * Remove a cfdriver from the system.
    */
   int
   config_cfdriver_detach(struct cfdriver *cd)
   {
           int i;
   
           /* Make sure there are no active instances. */
           for (i = 0; i < cd->cd_ndevs; i++) {
                   if (cd->cd_devs[i] != NULL)
                           return (EBUSY);
           }
   
           /* ...and no attachments loaded. */
           if (LIST_EMPTY(&cd->cd_attach) == 0)
                   return (EBUSY);
   
           LIST_REMOVE(cd, cd_list);
   
           KASSERT(cd->cd_devs == NULL);
   
           return (0);
   }
   
   /*
    * Look up a cfdriver by name.
    */
   struct cfdriver *
   config_cfdriver_lookup(const char *name)
   {
           struct cfdriver *cd;
   
           LIST_FOREACH(cd, &allcfdrivers, cd_list) {
                   if (STREQ(cd->cd_name, name))
                           return (cd);
           }
   
           return (NULL);
   }
   
   /*
    * Add a cfattach to the specified driver.
    */
   int
   config_cfattach_attach(const char *driver, struct cfattach *ca)
   {
           struct cfattach *lca;
           struct cfdriver *cd;
   
           cd = config_cfdriver_lookup(driver);
           if (cd == NULL)
                   return (ESRCH);
   
           /* Make sure this attachment isn't already on this driver. */
           LIST_FOREACH(lca, &cd->cd_attach, ca_list) {
                   if (STREQ(lca->ca_name, ca->ca_name))
                           return (EEXIST);
           }
   
           LIST_INSERT_HEAD(&cd->cd_attach, ca, ca_list);
   
           return (0);
   }
   
   /*
    * Remove a cfattach from the specified driver.
    */
   int
   config_cfattach_detach(const char *driver, struct cfattach *ca)
   {
           struct cfdriver *cd;
           device_t dev;
           int i;
   
           cd = config_cfdriver_lookup(driver);
           if (cd == NULL)
                   return (ESRCH);
   
           /* Make sure there are no active instances. */
           for (i = 0; i < cd->cd_ndevs; i++) {
                   if ((dev = cd->cd_devs[i]) == NULL)
                           continue;
                   if (dev->dv_cfattach == ca)
                           return (EBUSY);
           }
   
           LIST_REMOVE(ca, ca_list);
   
           return (0);
   }
   
   /*
    * Look up a cfattach by name.
    */
   static struct cfattach *
   config_cfattach_lookup_cd(struct cfdriver *cd, const char *atname)
   {
           struct cfattach *ca;
   
           LIST_FOREACH(ca, &cd->cd_attach, ca_list) {
                   if (STREQ(ca->ca_name, atname))
                           return (ca);
           }
   
           return (NULL);
   }
   
   /*
    * Look up a cfattach by driver/attachment name.
    */
   struct cfattach *
   config_cfattach_lookup(const char *name, const char *atname)
   {
           struct cfdriver *cd;
   
           cd = config_cfdriver_lookup(name);
           if (cd == NULL)
                   return (NULL);
   
           return (config_cfattach_lookup_cd(cd, atname));
   }
   
   /*
    * 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, cfdata_t cf)
   {
           int pri;
   
           if (m->fn != NULL) {
                   pri = (*m->fn)(m->parent, cf, m->locs, m->aux);
           } else {
                   pri = config_match(m->parent, cf, m->aux);
           }
           if (pri > m->pri) {
                   m->match = cf;
                   m->pri = pri;
           }
   }
   
   int
   config_stdsubmatch(device_t parent, cfdata_t cf, const int *locs, void *aux)
   {
           const struct cfiattrdata *ci;
           const struct cflocdesc *cl;
           int nlocs, i;
   
           ci = cfiattr_lookup(cf->cf_pspec->cfp_iattr, parent->dv_cfdriver);
           KASSERT(ci);
           nlocs = ci->ci_loclen;
           KASSERT(!nlocs || locs);
           for (i = 0; i < nlocs; i++) {
                   cl = &ci->ci_locdesc[i];
                   /* !cld_defaultstr means no default value */
                   if ((!(cl->cld_defaultstr)
                        || (cf->cf_loc[i] != cl->cld_default))
                       && cf->cf_loc[i] != locs[i])
                           return (0);
           }
   
           return (config_match(parent, cf, aux));
   }
   
   /*
    * Helper function: check whether the driver supports the interface attribute
    * and return its descriptor structure.
    */
   static const struct cfiattrdata *
   cfdriver_get_iattr(const struct cfdriver *cd, const char *ia)
   {
           const struct cfiattrdata * const *cpp;
   
           if (cd->cd_attrs == NULL)
                   return (0);
   
           for (cpp = cd->cd_attrs; *cpp; cpp++) {
                   if (STREQ((*cpp)->ci_name, ia)) {
                           /* Match. */
                           return (*cpp);
                   }
           }
           return (0);
   }
   
   /*
    * Lookup an interface attribute description by name.
    * If the driver is given, consider only its supported attributes.
    */
   const struct cfiattrdata *
   cfiattr_lookup(const char *name, const struct cfdriver *cd)
   {
           const struct cfdriver *d;
           const struct cfiattrdata *ia;
   
           if (cd)
                   return (cfdriver_get_iattr(cd, name));
   
           LIST_FOREACH(d, &allcfdrivers, cd_list) {
                   ia = cfdriver_get_iattr(d, name);
                   if (ia)
                           return (ia);
           }
           return (0);
   }
   
   /*
    * Determine if `parent' is a potential parent for a device spec based
    * on `cfp'.
    */
   static int
   cfparent_match(const device_t parent, const struct cfparent *cfp)
   {
           struct cfdriver *pcd;
   
           /* We don't match root nodes here. */
           if (cfp == NULL)
                   return (0);
   
           pcd = parent->dv_cfdriver;
           KASSERT(pcd != NULL);
   
           /*
            * First, ensure this parent has the correct interface
            * attribute.
            */
           if (!cfdriver_get_iattr(pcd, cfp->cfp_iattr))
                   return (0);
   
           /*
            * If no specific parent device instance was specified (i.e.
            * we're attaching to the attribute only), we're done!
            */
           if (cfp->cfp_parent == NULL)
                   return (1);
   
           /*
            * Check the parent device's name.
            */
           if (STREQ(pcd->cd_name, cfp->cfp_parent) == 0)
                   return (0);     /* not the same parent */
   
           /*
            * Make sure the unit number matches.
            */
           if (cfp->cfp_unit == DVUNIT_ANY ||      /* wildcard */
               cfp->cfp_unit == parent->dv_unit)
                   return (1);
   
           /* Unit numbers don't match. */
           return (0);
   }
   
   /*
    * Helper for config_cfdata_attach(): check all devices whether it could be
    * parent any attachment in the config data table passed, and rescan.
    */
   static void
   rescan_with_cfdata(const struct cfdata *cf)
   {
           device_t d;
           const struct cfdata *cf1;
           deviter_t di;
     
   
           /*
            * "alldevs" is likely longer than an LKM's cfdata, so make it
            * the outer loop.
            */
           for (d = deviter_first(&di, 0); d != NULL; d = deviter_next(&di)) {
   
                   if (!(d->dv_cfattach->ca_rescan))
                           continue;
   
                   for (cf1 = cf; cf1->cf_name; cf1++) {
   
                           if (!cfparent_match(d, cf1->cf_pspec))
                                   continue;
   
                           (*d->dv_cfattach->ca_rescan)(d,
                                   cf1->cf_pspec->cfp_iattr, cf1->cf_loc);
                   }
           }
           deviter_release(&di);
   }
   
   /*
    * Attach a supplemental config data table and rescan potential
    * parent devices if required.
    */
   int
   config_cfdata_attach(cfdata_t cf, int scannow)
   {
           struct cftable *ct;
   
           ct = kmem_alloc(sizeof(*ct), KM_SLEEP);
           ct->ct_cfdata = cf;
           TAILQ_INSERT_TAIL(&allcftables, ct, ct_list);
   
           if (scannow)
                   rescan_with_cfdata(cf);
   
           return (0);
   }
   
   /*
    * Helper for config_cfdata_detach: check whether a device is
    * found through any attachment in the config data table.
    */
   static int
   dev_in_cfdata(const struct device *d, const struct cfdata *cf)
   {
           const struct cfdata *cf1;
   
           for (cf1 = cf; cf1->cf_name; cf1++)
                   if (d->dv_cfdata == cf1)
                           return (1);
   
           return (0);
   }
   
   /*
    * Detach a supplemental config data table. Detach all devices found
    * through that table (and thus keeping references to it) before.
    */
   int
   config_cfdata_detach(cfdata_t cf)
   {
           device_t d;
           int error = 0;
           struct cftable *ct;
           deviter_t di;
   
           for (d = deviter_first(&di, DEVITER_F_RW); d != NULL;
                d = deviter_next(&di)) {
                   if (!dev_in_cfdata(d, cf))
                           continue;
                   if ((error = config_detach(d, 0)) != 0)
                           break;
           }
           deviter_release(&di);
           if (error) {
                   aprint_error_dev(d, "unable to detach instance\n");
                   return error;
           }
   
           TAILQ_FOREACH(ct, &allcftables, ct_list) {
                   if (ct->ct_cfdata == cf) {
                           TAILQ_REMOVE(&allcftables, ct, ct_list);
                           kmem_free(ct, sizeof(*ct));
                           return (0);
                   }
           }
   
           /* not found -- shouldn't happen */
           return (EINVAL);
   }
   
   /*
    * Invoke the "match" routine for a cfdata entry on behalf of
    * an external caller, usually a "submatch" routine.
    */
   int
   config_match(device_t parent, cfdata_t cf, void *aux)
   {
           struct cfattach *ca;
   
           ca = config_cfattach_lookup(cf->cf_name, cf->cf_atname);
           if (ca == NULL) {
                   /* No attachment for this entry, oh well. */
                   return (0);
           }
   
           return ((*ca->ca_match)(parent, cf, aux));
   }
   
   /*
    * 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).
    */
   cfdata_t
   config_search_loc(cfsubmatch_t fn, device_t parent,
                     const char *ifattr, const int *locs, void *aux)
   {
           struct cftable *ct;
           cfdata_t cf;
           struct matchinfo m;
   
           KASSERT(config_initialized);
           KASSERT(!ifattr || cfdriver_get_iattr(parent->dv_cfdriver, ifattr));
   
           m.fn = fn;
           m.parent = parent;
           m.locs = locs;
           m.aux = aux;
           m.match = NULL;
           m.pri = 0;
   
           TAILQ_FOREACH(ct, &allcftables, ct_list) {
                   for (cf = ct->ct_cfdata; cf->cf_name; cf++) {
   
                           /* We don't match root nodes here. */
                           if (!cf->cf_pspec)
                                   continue;
   
                           /*
                            * 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;
                           if (cf->cf_fstate == FSTATE_DNOTFOUND ||
                               cf->cf_fstate == FSTATE_DSTAR)
                                   continue;
   
                           /*
                            * If an interface attribute was specified,
                            * consider only children which attach to
                            * that attribute.
                            */
                           if (ifattr && !STREQ(ifattr, cf->cf_pspec->cfp_iattr))
                                   continue;
   
                           if (cfparent_match(parent, cf->cf_pspec))
                                   mapply(&m, cf);
                   }
           }
           return (m.match);
   }
   
   cfdata_t
   config_search_ia(cfsubmatch_t fn, device_t parent, const char *ifattr,
       void *aux)
   {
   
           return (config_search_loc(fn, parent, ifattr, NULL, aux));
   }
   
   /*
    * Find the given root device.
    * This is much like config_search, but there is no parent.
    * Don't bother with multiple cfdata tables; the root node
    * must always be in the initial table.
    */
   cfdata_t
   config_rootsearch(cfsubmatch_t fn, const char *rootname, void *aux)
   {
           cfdata_t cf;
           const short *p;
           struct matchinfo m;
   
           m.fn = fn;
           m.parent = ROOT;
           m.aux = aux;
           m.match = NULL;
           m.pri = 0;
           m.locs = 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_name, rootname) == 0)
                          mapply(&m, cf);
          }
          return (m.match);
  }
  
  static const char * const 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.
   */
  device_t
  config_found_sm_loc(device_t parent,
                  const char *ifattr, const int *locs, void *aux,
                  cfprint_t print, cfsubmatch_t submatch)
  {
          cfdata_t cf;
  
  #if defined(SPLASHSCREEN) && defined(SPLASHSCREEN_PROGRESS)
          if (splash_progress_state)
                  splash_progress_update(splash_progress_state);
  #endif
  
          if ((cf = config_search_loc(submatch, parent, ifattr, locs, aux)))
                  return(config_attach_loc(parent, cf, locs, aux, print));
          if (print) {
                  if (config_do_twiddle)
                          twiddle();
                  aprint_normal("%s", msgs[(*print)(aux, device_xname(parent))]);
          }
  
  #if defined(SPLASHSCREEN) && defined(SPLASHSCREEN_PROGRESS)
          if (splash_progress_state)
                  splash_progress_update(splash_progress_state);
  #endif
  
          return (NULL);
  }
  
  device_t
  config_found_ia(device_t parent, const char *ifattr, void *aux,
      cfprint_t print)
  {
  
          return (config_found_sm_loc(parent, ifattr, NULL, aux, print, NULL));
  }
  
  device_t
  config_found(device_t parent, void *aux, cfprint_t print)
  {
  
          return (config_found_sm_loc(parent, NULL, NULL, aux, print, NULL));
  }
  
  /*
   * As above, but for root devices.
   */
  device_t
  config_rootfound(const char *rootname, void *aux)
  {
          cfdata_t cf;
  
          if ((cf = config_rootsearch((cfsubmatch_t)NULL, rootname, aux)) != NULL)
                  return (config_attach(ROOT, cf, aux, (cfprint_t)NULL));
          aprint_error("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) + '';
                  n /= 10;
          }
          *--ep = n + '';
          return (ep);
  }
  
  /*
   * Expand the size of the cd_devs array if necessary.
   */
  static void
  config_makeroom(int n, struct cfdriver *cd)
  {
          const km_flag_t kmflags = (cold ? KM_NOSLEEP : KM_SLEEP);
          int old, new;
          device_t *nsp;
  
          if (n < cd->cd_ndevs)
                  return;
  
          /*
           * Need to expand the array.
           */
          old = cd->cd_ndevs;
          if (old == 0)
                  new = 4;
          else
                  new = old * 2;
          while (new <= n)
                  new *= 2;
          cd->cd_ndevs = new;
          nsp = kmem_alloc(sizeof(device_t [new]), kmflags);
          if (nsp == NULL)
                  panic("config_attach: %sing dev array",
                      old != 0 ? "expand" : "creat");
          memset(nsp + old, 0, sizeof(device_t [new - old]));
          if (old != 0) {
                  memcpy(nsp, cd->cd_devs, sizeof(device_t [old]));
                  kmem_free(cd->cd_devs, sizeof(device_t [old]));
          }
          cd->cd_devs = nsp;
  }
  
  static void
  config_devlink(device_t dev)
  {
          struct cfdriver *cd = dev->dv_cfdriver;
  
          /* 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", device_xname(dev));
          cd->cd_devs[dev->dv_unit] = dev;
  
          /* It is safe to add a device to the tail of the list while
           * readers are in the list, but not while a writer is in
           * the list.  Wait for any writer to complete.
           */
          mutex_enter(&alldevs_mtx);
          while (alldevs_nwrite != 0 && alldevs_writer != curlwp)
                  cv_wait(&alldevs_cv, &alldevs_mtx);
          TAILQ_INSERT_TAIL(&alldevs, dev, dv_list);      /* link up */
          cv_signal(&alldevs_cv);
          mutex_exit(&alldevs_mtx);
  }
  
  static void
  config_devunlink(device_t dev)
  {
          struct cfdriver *cd = dev->dv_cfdriver;
          int i;
  
          /* Unlink from device list. */
          TAILQ_REMOVE(&alldevs, dev, dv_list);
  
          /* Remove from cfdriver's array. */
          cd->cd_devs[dev->dv_unit] = NULL;
  
          /*
           * 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)
                          return;
          }
          /* nothing found; deallocate */
          kmem_free(cd->cd_devs, sizeof(device_t [cd->cd_ndevs]));
          cd->cd_devs = NULL;
          cd->cd_ndevs = 0;
  }
          
  static device_t
  config_devalloc(const device_t parent, const cfdata_t cf, const int *locs)
  {
          struct cfdriver *cd;
          struct cfattach *ca;
          size_t lname, lunit;
          const char *xunit;
          int myunit;
          char num[10];
          device_t dev;
          void *dev_private;
          const struct cfiattrdata *ia;
          const km_flag_t kmflags = (cold ? KM_NOSLEEP : KM_SLEEP);
  
          cd = config_cfdriver_lookup(cf->cf_name);
          if (cd == NULL)
                  return (NULL);
  
          ca = config_cfattach_lookup_cd(cd, cf->cf_atname);
          if (ca == NULL)
                  return (NULL);
  
          if ((ca->ca_flags & DVF_PRIV_ALLOC) == 0 &&
              ca->ca_devsize < sizeof(struct device))
                  panic("config_devalloc: %s", cf->cf_atname);
  
  #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;
                  if (myunit < cd->cd_ndevs && cd->cd_devs[myunit] != NULL)
                          return (NULL);
          }       
  #else
          myunit = cf->cf_unit;
  #endif /* ! __BROKEN_CONFIG_UNIT_USAGE */
  
          /* 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_devalloc: device name too long");
  
          /* get memory for all device vars */
          KASSERT((ca->ca_flags & DVF_PRIV_ALLOC) || ca->ca_devsize >= sizeof(struct device));
          if (ca->ca_devsize > 0) {
                  dev_private = kmem_zalloc(ca->ca_devsize, kmflags);
                  if (dev_private == NULL)
                          panic("config_devalloc: memory allocation for device softc failed");
          } else {
                  KASSERT(ca->ca_flags & DVF_PRIV_ALLOC);
                  dev_private = NULL;
          }
  
          if ((ca->ca_flags & DVF_PRIV_ALLOC) != 0) {
                  dev = kmem_zalloc(sizeof(*dev), kmflags);
          } else {
                  dev = dev_private;
          }
          if (dev == NULL)
                  panic("config_devalloc: memory allocation for device_t failed");
  
          dev->dv_class = cd->cd_class;
          dev->dv_cfdata = cf;
          dev->dv_cfdriver = cd;
          dev->dv_cfattach = ca;
          dev->dv_unit = myunit;
          dev->dv_activity_count = 0;
          dev->dv_activity_handlers = NULL;
          dev->dv_private = dev_private;
          memcpy(dev->dv_xname, cd->cd_name, lname);
          memcpy(dev->dv_xname + lname, xunit, lunit);
          dev->dv_parent = parent;
          if (parent != NULL)
                  dev->dv_depth = parent->dv_depth + 1;
          else
                  dev->dv_depth = 0;
          dev->dv_flags = DVF_ACTIVE;     /* always initially active */
          dev->dv_flags |= ca->ca_flags;  /* inherit flags from class */
          if (locs) {
                  KASSERT(parent); /* no locators at root */
                  ia = cfiattr_lookup(cf->cf_pspec->cfp_iattr,
                                      parent->dv_cfdriver);
                  dev->dv_locators =
                      kmem_alloc(sizeof(int [ia->ci_loclen + 1]), kmflags);
                  *dev->dv_locators++ = sizeof(int [ia->ci_loclen + 1]);
                  memcpy(dev->dv_locators, locs, sizeof(int [ia->ci_loclen]));
          }
          dev->dv_properties = prop_dictionary_create();
          KASSERT(dev->dv_properties != NULL);
  
          prop_dictionary_set_cstring_nocopy(dev->dv_properties,
              "device-driver", dev->dv_cfdriver->cd_name);
          prop_dictionary_set_uint16(dev->dv_properties,
              "device-unit", dev->dv_unit);
  
          return (dev);
  }
  
  static void
  config_devdealloc(device_t dev)
  {
          int priv = (dev->dv_flags & DVF_PRIV_ALLOC);
  
          KASSERT(dev->dv_properties != NULL);
          prop_object_release(dev->dv_properties);
  
          if (dev->dv_activity_handlers)
                  panic("config_devdealloc with registered handlers");
  
          if (dev->dv_locators) {
                  size_t amount = *--dev->dv_locators;
                  kmem_free(dev->dv_locators, amount);
          }
  
          if (dev->dv_cfattach->ca_devsize > 0)
                  kmem_free(dev->dv_private, dev->dv_cfattach->ca_devsize);
          if (priv)
                  kmem_free(dev, sizeof(*dev));
  }
  
  /*
   * Attach a found device.
   */
  device_t
  config_attach_loc(device_t parent, cfdata_t cf,
          const int *locs, void *aux, cfprint_t print)
  {
          device_t dev;
          struct cftable *ct;
          const char *drvname;
  
  #if defined(SPLASHSCREEN) && defined(SPLASHSCREEN_PROGRESS)
          if (splash_progress_state)
                  splash_progress_update(splash_progress_state);
  #endif
  
          dev = config_devalloc(parent, cf, locs);
          if (!dev)
                  panic("config_attach: allocation of device softc failed");
  
          /* XXX redundant - see below? */
          if (cf->cf_fstate != FSTATE_STAR) {
                  KASSERT(cf->cf_fstate == FSTATE_NOTFOUND);
                  cf->cf_fstate = FSTATE_FOUND;
          }
  #ifdef __BROKEN_CONFIG_UNIT_USAGE
            else
                  cf->cf_unit++;
  #endif
  
          config_devlink(dev);
  
          if (config_do_twiddle)
                  twiddle();
          else
                  aprint_naive("Found ");
          /*
           * We want the next two printfs for normal, verbose, and quiet,
           * but not silent (in which case, we're twiddling, instead).
           */
          if (parent == ROOT) {
                  aprint_naive("%s (root)", device_xname(dev));
                  aprint_normal("%s (root)", device_xname(dev));
          } else {
                  aprint_naive("%s at %s", device_xname(dev), device_xname(parent));
                  aprint_normal("%s at %s", device_xname(dev), device_xname(parent));
                  if (print)
                          (void) (*print)(aux, NULL);
          }
  
          /*
           * Before attaching, clobber any unfound devices that are
           * otherwise identical.
           * XXX code above is redundant?
           */
          drvname = dev->dv_cfdriver->cd_name;
          TAILQ_FOREACH(ct, &allcftables, ct_list) {
                  for (cf = ct->ct_cfdata; cf->cf_name; cf++) {
                          if (STREQ(cf->cf_name, drvname) &&
                              cf->cf_unit == dev->dv_unit) {
                                  if (cf->cf_fstate == FSTATE_NOTFOUND)
                                          cf->cf_fstate = FSTATE_FOUND;
  #ifdef __BROKEN_CONFIG_UNIT_USAGE
                                  /*
                                   * Bump the unit number on all starred cfdata
                                   * entries for this device.
                                   */
                                  if (cf->cf_fstate == FSTATE_STAR)
                                          cf->cf_unit++;
  #endif /* __BROKEN_CONFIG_UNIT_USAGE */
                          }
                  }
          }
  #ifdef __HAVE_DEVICE_REGISTER
          device_register(dev, aux);
  #endif
  
          /* Let userland know */
          devmon_report_device(dev, true);
  
  #if defined(SPLASHSCREEN) && defined(SPLASHSCREEN_PROGRESS)
          if (splash_progress_state)
                  splash_progress_update(splash_progress_state);
  #endif
          (*dev->dv_cfattach->ca_attach)(parent, dev, aux);
  #if defined(SPLASHSCREEN) && defined(SPLASHSCREEN_PROGRESS)
          if (splash_progress_state)
                  splash_progress_update(splash_progress_state);
  #endif
  
          if (!device_pmf_is_registered(dev))
                  aprint_debug_dev(dev, "WARNING: power management not supported\n");
  
          config_process_deferred(&deferred_config_queue, dev);
          return (dev);
  }
  
  device_t
  config_attach(device_t parent, cfdata_t cf, void *aux, cfprint_t print)
  {
  
          return (config_attach_loc(parent, cf, NULL, aux, print));
  }
  
  /*
   * As above, but for pseudo-devices.  Pseudo-devices attached in this
   * way are silently inserted into the device tree, and their children
   * attached.
   *
   * Note that because pseudo-devices are attached silently, any information
   * the attach routine wishes to print should be prefixed with the device
   * name by the attach routine.
   */
  device_t
  config_attach_pseudo(cfdata_t cf)
  {
          device_t dev;
  
          dev = config_devalloc(ROOT, cf, NULL);
          if (!dev)
                  return (NULL);
  
          /* XXX mark busy in cfdata */
  
          config_devlink(dev);
  
  #if 0   /* XXXJRT not yet */
  #ifdef __HAVE_DEVICE_REGISTER
          device_register(dev, NULL);     /* like a root node */
  #endif
  #endif
          (*dev->dv_cfattach->ca_attach)(ROOT, dev, NULL);
          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(device_t dev, int flags)
  {
          struct cftable *ct;
          cfdata_t cf;
          const struct cfattach *ca;
          struct cfdriver *cd;
  #ifdef DIAGNOSTIC
          device_t d;
  #endif
          int rv = 0;
  
  #ifdef DIAGNOSTIC
          cf = dev->dv_cfdata;
          if (cf != NULL && cf->cf_fstate != FSTATE_FOUND &&
              cf->cf_fstate != FSTATE_STAR)
                  panic("config_detach: %s: bad device fstate %d",
                      device_xname(dev), cf ? cf->cf_fstate : -1);
  #endif
          cd = dev->dv_cfdriver;
          KASSERT(cd != NULL);
  
          ca = dev->dv_cfattach;
          KASSERT(ca != NULL);
  
          KASSERT(curlwp != NULL);
          mutex_enter(&alldevs_mtx);
          if (alldevs_nwrite > 0 && alldevs_writer == NULL)
                  ;
          else while (alldevs_nread != 0 ||
                 (alldevs_nwrite != 0 && alldevs_writer != curlwp))
                  cv_wait(&alldevs_cv, &alldevs_mtx);
          if (alldevs_nwrite++ == 0)
                  alldevs_writer = curlwp;
          mutex_exit(&alldevs_mtx);
  
          /*
           * 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)
                          goto out;
                  else
                          panic("config_detach: forced detach of %s failed (%d)",
                              device_xname(dev), rv);
          }
  
          /*
           * The device has now been successfully detached.
           */
  
          /* Let userland know */
          devmon_report_device(dev, false);
  
  #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", device_xname(dev), device_xname(d));
                          panic("config_detach");
                  }
          }
  #endif
  
          /* notify the parent that the child is gone */
          if (dev->dv_parent) {
                  device_t p = dev->dv_parent;
                  if (p->dv_cfattach->ca_childdetached)
                          (*p->dv_cfattach->ca_childdetached)(p, dev);
          }
  
          /*
           * Mark cfdata to show that the unit can be reused, if possible.
           */
          TAILQ_FOREACH(ct, &allcftables, ct_list) {
                  for (cf = ct->ct_cfdata; cf->cf_name; cf++) {
                          if (STREQ(cf->cf_name, cd->cd_name)) {
                                  if (cf->cf_fstate == FSTATE_FOUND &&
                                      cf->cf_unit == dev->dv_unit)
                                          cf->cf_fstate = FSTATE_NOTFOUND;
  #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.
                                   */
                                  if (cf->cf_fstate == FSTATE_STAR &&
                                      cf->cf_unit == dev->dv_unit + 1)
                                          cf->cf_unit--;
  #endif /* __BROKEN_CONFIG_UNIT_USAGE */
                          }
                  }
          }
  
          config_devunlink(dev);
  
          if (dev->dv_cfdata != NULL && (flags & DETACH_QUIET) == 0)
                  aprint_normal_dev(dev, "detached\n");
  
          config_devdealloc(dev);
  
  out:
          mutex_enter(&alldevs_mtx);
          if (--alldevs_nwrite == 0)
                  alldevs_writer = NULL;
          cv_signal(&alldevs_cv);
          mutex_exit(&alldevs_mtx);
          return rv;
  }
  
  int
  config_detach_children(device_t parent, int flags)
  {
          device_t dv;
          deviter_t di;
          int error = 0;
  
          for (dv = deviter_first(&di, DEVITER_F_RW); dv != NULL;
               dv = deviter_next(&di)) {
                  if (device_parent(dv) != parent)
                          continue;
                  if ((error = config_detach(dv, flags)) != 0)
                          break;
          }
          deviter_release(&di);
          return error;
  }
  
  int
  config_activate(device_t dev)
  {
          const struct cfattach *ca = dev->dv_cfattach;
          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(device_t dev)
  {
          const struct cfattach *ca = dev->dv_cfattach;
          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(device_t dev, void (*func)(device_t))
  {
          const km_flag_t kmflags = (cold ? KM_NOSLEEP : KM_SLEEP);
          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 = kmem_alloc(sizeof(*dc), kmflags);
          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(device_t dev, void (*func)(device_t))
  {
          const km_flag_t kmflags = (cold ? KM_NOSLEEP : KM_SLEEP);
          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 = kmem_alloc(sizeof(*dc), kmflags);
          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,
      device_t 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);
                          kmem_free(dc, sizeof(*dc));
                          config_pending_decr();
                  }
          }
  }
  
  /*
   * Manipulate the config_pending semaphore.
   */
  void
  config_pending_incr(void)
  {
  
          mutex_enter(&config_misc_lock);
          config_pending++;
          mutex_exit(&config_misc_lock);
  }
  
  void
  config_pending_decr(void)
  {
  
  #ifdef DIAGNOSTIC
          if (config_pending == 0)
                  panic("config_pending_decr: config_pending == 0");
  #endif
          mutex_enter(&config_misc_lock);
          config_pending--;
          if (config_pending == 0)
                  cv_broadcast(&config_misc_cv);
          mutex_exit(&config_misc_lock);
  }
  
  /*
   * Register a "finalization" routine.  Finalization routines are
   * called iteratively once all real devices have been found during
   * autoconfiguration, for as long as any one finalizer has done
   * any work.
   */
  int
  config_finalize_register(device_t dev, int (*fn)(device_t))
  {
          struct finalize_hook *f;
  
          /*
           * If finalization has already been done, invoke the
           * callback function now.
           */
          if (config_finalize_done) {
                  while ((*fn)(dev) != 0)
                          /* loop */ ;
          }
  
          /* Ensure this isn't already on the list. */
          TAILQ_FOREACH(f, &config_finalize_list, f_list) {
                  if (f->f_func == fn && f->f_dev == dev)
                          return (EEXIST);
          }
  
          f = kmem_alloc(sizeof(*f), KM_SLEEP);
          f->f_func = fn;
          f->f_dev = dev;
          TAILQ_INSERT_TAIL(&config_finalize_list, f, f_list);
  
          return (0);
  }
  
  void
  config_finalize(void)
  {
          struct finalize_hook *f;
          struct pdevinit *pdev;
          extern struct pdevinit pdevinit[];
          int errcnt, rv;
  
          /*
           * Now that device driver threads have been created, wait for
           * them to finish any deferred autoconfiguration.
           */
          mutex_enter(&config_misc_lock);
          while (config_pending != 0)
                  cv_wait(&config_misc_cv, &config_misc_lock);
          mutex_exit(&config_misc_lock);
  
          KERNEL_LOCK(1, NULL);
  
          /* Attach pseudo-devices. */
          for (pdev = pdevinit; pdev->pdev_attach != NULL; pdev++)
                  (*pdev->pdev_attach)(pdev->pdev_count);
  
          /* Run the hooks until none of them does any work. */
          do {
                  rv = 0;
                  TAILQ_FOREACH(f, &config_finalize_list, f_list)
                          rv |= (*f->f_func)(f->f_dev);
          } while (rv != 0);
  
          config_finalize_done = 1;
  
          /* Now free all the hooks. */
          while ((f = TAILQ_FIRST(&config_finalize_list)) != NULL) {
                  TAILQ_REMOVE(&config_finalize_list, f, f_list);
                  kmem_free(f, sizeof(*f));
          }
  
          KERNEL_UNLOCK_ONE(NULL);
  
          errcnt = aprint_get_error_count();
          if ((boothowto & (AB_QUIET|AB_SILENT)) != 0 &&
              (boothowto & AB_VERBOSE) == 0) {
                  if (config_do_twiddle) {
                          config_do_twiddle = 0;
                          printf_nolog(" done.\n");
                  }
                  if (errcnt != 0) {
                          printf("WARNING: %d error%s while detecting hardware; "
                              "check system log.\n", errcnt,
                              errcnt == 1 ? "" : "s");
                  }
          }
  }
  
  /*
   * device_lookup:
   *
   *      Look up a device instance for a given driver.
   */
  device_t
  device_lookup(cfdriver_t cd, int unit)
  {
  
          if (unit < 0 || unit >= cd->cd_ndevs)
                  return (NULL);
          
          return (cd->cd_devs[unit]);
  }
  
  /*
   * device_lookup:
   *
   *      Look up a device instance for a given driver.
   */
  void *
  device_lookup_private(cfdriver_t cd, int unit)
  {
          device_t dv;
  
          if (unit < 0 || unit >= cd->cd_ndevs)
                  return NULL;
          
          if ((dv = cd->cd_devs[unit]) == NULL)
                  return NULL;
  
          return dv->dv_private;
  }
  
  /*
   * Accessor functions for the device_t type.
   */
  devclass_t
  device_class(device_t dev)
  {
  
          return (dev->dv_class);
  }
  
  cfdata_t
  device_cfdata(device_t dev)
  {
  
          return (dev->dv_cfdata);
  }
  
  cfdriver_t
  device_cfdriver(device_t dev)
  {
  
          return (dev->dv_cfdriver);
  }
  
  cfattach_t
  device_cfattach(device_t dev)
  {
  
          return (dev->dv_cfattach);
  }
  
  int
  device_unit(device_t dev)
  {
  
          return (dev->dv_unit);
  }
  
  const char *
  device_xname(device_t dev)
  {
  
          return (dev->dv_xname);
  }
  
  device_t
  device_parent(device_t dev)
  {
  
          return (dev->dv_parent);
  }
  
  bool
  device_is_active(device_t dev)
  {
          int active_flags;
  
          active_flags = DVF_ACTIVE;
          active_flags |= DVF_CLASS_SUSPENDED;
          active_flags |= DVF_DRIVER_SUSPENDED;
          active_flags |= DVF_BUS_SUSPENDED;
  
          return ((dev->dv_flags & active_flags) == DVF_ACTIVE);
  }
  
  bool
  device_is_enabled(device_t dev)
  {
          return (dev->dv_flags & DVF_ACTIVE) == DVF_ACTIVE;
  }
  
  bool
  device_has_power(device_t dev)
  {
          int active_flags;
  
          active_flags = DVF_ACTIVE | DVF_BUS_SUSPENDED;
  
          return ((dev->dv_flags & active_flags) == DVF_ACTIVE);
  }
  
  int
  device_locator(device_t dev, u_int locnum)
  {
  
          KASSERT(dev->dv_locators != NULL);
          return (dev->dv_locators[locnum]);
  }
  
  void *
  device_private(device_t dev)
  {
  
          /*
           * The reason why device_private(NULL) is allowed is to simplify the
           * work of a lot of userspace request handlers (i.e., c/bdev
           * handlers) which grab cfdriver_t->cd_units[n].
           * It avoids having them test for it to be NULL and only then calling
           * device_private.
           */
          return dev == NULL ? NULL : dev->dv_private;
  }
  
  prop_dictionary_t
  device_properties(device_t dev)
  {
  
          return (dev->dv_properties);
  }
  
  /*
   * device_is_a:
   *
   *      Returns true if the device is an instance of the specified
   *      driver.
   */
  bool
  device_is_a(device_t dev, const char *dname)
  {
  
          return (strcmp(dev->dv_cfdriver->cd_name, dname) == 0);
  }
  
  /*
   * device_find_by_xname:
   *
   *      Returns the device of the given name or NULL if it doesn't exist.
   */
  device_t
  device_find_by_xname(const char *name)
  {
          device_t dv;
          deviter_t di;
  
          for (dv = deviter_first(&di, 0); dv != NULL; dv = deviter_next(&di)) {
                  if (strcmp(device_xname(dv), name) == 0)
                          break;
          }
          deviter_release(&di);
  
          return dv;
  }
  
  /*
   * device_find_by_driver_unit:
   *
   *      Returns the device of the given driver name and unit or
   *      NULL if it doesn't exist.
   */
  device_t
  device_find_by_driver_unit(const char *name, int unit)
  {
          struct cfdriver *cd;
  
          if ((cd = config_cfdriver_lookup(name)) == NULL)
                  return NULL;
          return device_lookup(cd, unit);
  }
  
  /*
   * Power management related functions.
   */
  
  bool
  device_pmf_is_registered(device_t dev)
  {
          return (dev->dv_flags & DVF_POWER_HANDLERS) != 0;
  }
  
  bool
  device_pmf_driver_suspend(device_t dev PMF_FN_ARGS)
  {
          if ((dev->dv_flags & DVF_DRIVER_SUSPENDED) != 0)
                  return true;
          if ((dev->dv_flags & DVF_CLASS_SUSPENDED) == 0)
                  return false;
          if (*dev->dv_driver_suspend != NULL &&
              !(*dev->dv_driver_suspend)(dev PMF_FN_CALL))
                  return false;
  
          dev->dv_flags |= DVF_DRIVER_SUSPENDED;
          return true;
  }
  
  bool
  device_pmf_driver_resume(device_t dev PMF_FN_ARGS)
  {
          if ((dev->dv_flags & DVF_DRIVER_SUSPENDED) == 0)
                  return true;
          if ((dev->dv_flags & DVF_BUS_SUSPENDED) != 0)
                  return false;
          if ((flags & PMF_F_SELF) != 0 && !device_is_self_suspended(dev))
                  return false;
          if (*dev->dv_driver_resume != NULL &&
              !(*dev->dv_driver_resume)(dev PMF_FN_CALL))
                  return false;
  
          dev->dv_flags &= ~DVF_DRIVER_SUSPENDED;
          return true;
  }
  
  bool
  device_pmf_driver_shutdown(device_t dev, int how)
  {
  
          if (*dev->dv_driver_shutdown != NULL &&
              !(*dev->dv_driver_shutdown)(dev, how))
                  return false;
          return true;
  }
  
  bool
  device_pmf_driver_register(device_t dev,
      bool (*suspend)(device_t PMF_FN_PROTO),
      bool (*resume)(device_t PMF_FN_PROTO),
      bool (*shutdown)(device_t, int))
  {
          pmf_private_t *pp;
  
          if ((pp = kmem_zalloc(sizeof(*pp), KM_NOSLEEP)) == NULL)
                  return false;
          mutex_init(&pp->pp_mtx, MUTEX_DEFAULT, IPL_NONE);
          cv_init(&pp->pp_cv, "pmfsusp");
          dev->dv_pmf_private = pp;
  
          dev->dv_driver_suspend = suspend;
          dev->dv_driver_resume = resume;
          dev->dv_driver_shutdown = shutdown;
          dev->dv_flags |= DVF_POWER_HANDLERS;
          return true;
  }
  
  static const char *
  curlwp_name(void)
  {
          if (curlwp->l_name != NULL)
                  return curlwp->l_name;
          else
                  return curlwp->l_proc->p_comm;
  }
  
  void
  device_pmf_driver_deregister(device_t dev)
  {
          pmf_private_t *pp = dev->dv_pmf_private;
  
          /* XXX avoid crash in case we are not initialized */
          if (!pp)
                  return;
  
          dev->dv_driver_suspend = NULL;
          dev->dv_driver_resume = NULL;
  
          mutex_enter(&pp->pp_mtx);
          dev->dv_flags &= ~DVF_POWER_HANDLERS;
          while (pp->pp_nlock > 0 || pp->pp_nwait > 0) {
                  /* Wake a thread that waits for the lock.  That
                   * thread will fail to acquire the lock, and then
                   * it will wake the next thread that waits for the
                   * lock, or else it will wake us.
                   */
                  cv_signal(&pp->pp_cv);
                  pmflock_debug(dev, __func__, __LINE__);
                  cv_wait(&pp->pp_cv, &pp->pp_mtx);
                  pmflock_debug(dev, __func__, __LINE__);
          }
          dev->dv_pmf_private = NULL;
          mutex_exit(&pp->pp_mtx);
  
          cv_destroy(&pp->pp_cv);
          mutex_destroy(&pp->pp_mtx);
          kmem_free(pp, sizeof(*pp));
  }
  
  bool
  device_pmf_driver_child_register(device_t dev)
  {
          device_t parent = device_parent(dev);
  
          if (parent == NULL || parent->dv_driver_child_register == NULL)
                  return true;
          return (*parent->dv_driver_child_register)(dev);
  }
  
  void
  device_pmf_driver_set_child_register(device_t dev,
      bool (*child_register)(device_t))
  {
          dev->dv_driver_child_register = child_register;
  }
  
  void
  device_pmf_self_resume(device_t dev PMF_FN_ARGS)
  {
          pmflock_debug_with_flags(dev, __func__, __LINE__ PMF_FN_CALL);
          if ((dev->dv_flags & DVF_SELF_SUSPENDED) != 0)
                  dev->dv_flags &= ~DVF_SELF_SUSPENDED;
          pmflock_debug_with_flags(dev, __func__, __LINE__ PMF_FN_CALL);
  }
  
  bool
  device_is_self_suspended(device_t dev)
  {
          return (dev->dv_flags & DVF_SELF_SUSPENDED) != 0;
  }
  
  void
  device_pmf_self_suspend(device_t dev PMF_FN_ARGS)
  {
          bool self = (flags & PMF_F_SELF) != 0;
  
          pmflock_debug_with_flags(dev, __func__, __LINE__ PMF_FN_CALL);
  
          if (!self)
                  dev->dv_flags &= ~DVF_SELF_SUSPENDED;
          else if (device_is_active(dev))
                  dev->dv_flags |= DVF_SELF_SUSPENDED;
  
          pmflock_debug_with_flags(dev, __func__, __LINE__ PMF_FN_CALL);
  }
  
  static void
  pmflock_debug(device_t dev, const char *func, int line)
  {
          pmf_private_t *pp = device_pmf_private(dev);
  
          aprint_debug_dev(dev, "%s.%d, %s pp_nlock %d pp_nwait %d dv_flags %x\n",
              func, line, curlwp_name(), pp->pp_nlock, pp->pp_nwait,
              dev->dv_flags);
  }
  
  static void
  pmflock_debug_with_flags(device_t dev, const char *func, int line PMF_FN_ARGS)
  {
          pmf_private_t *pp = device_pmf_private(dev);
  
          aprint_debug_dev(dev, "%s.%d, %s pp_nlock %d pp_nwait %d dv_flags %x "
              "flags " PMF_FLAGS_FMT "\n", func, line, curlwp_name(),
              pp->pp_nlock, pp->pp_nwait, dev->dv_flags PMF_FN_CALL);
  }
  
  static bool
  device_pmf_lock1(device_t dev PMF_FN_ARGS)
  {
          pmf_private_t *pp = device_pmf_private(dev);
  
          while (device_pmf_is_registered(dev) &&
              pp->pp_nlock > 0 && pp->pp_holder != curlwp) {
                  pp->pp_nwait++;
                  pmflock_debug_with_flags(dev, __func__, __LINE__ PMF_FN_CALL);
                  cv_wait(&pp->pp_cv, &pp->pp_mtx);
                  pmflock_debug_with_flags(dev, __func__, __LINE__ PMF_FN_CALL);
                  pp->pp_nwait--;
          }
          if (!device_pmf_is_registered(dev)) {
                  pmflock_debug_with_flags(dev, __func__, __LINE__ PMF_FN_CALL);
                  /* We could not acquire the lock, but some other thread may
                   * wait for it, also.  Wake that thread.
                   */
                  cv_signal(&pp->pp_cv);
                  return false;
          }
          pp->pp_nlock++;
          pp->pp_holder = curlwp;
          pmflock_debug_with_flags(dev, __func__, __LINE__ PMF_FN_CALL);
          return true;
  }
  
  bool
  device_pmf_lock(device_t dev PMF_FN_ARGS)
  {
          bool rc;
          pmf_private_t *pp = device_pmf_private(dev);
  
          mutex_enter(&pp->pp_mtx);
          rc = device_pmf_lock1(dev PMF_FN_CALL);
          mutex_exit(&pp->pp_mtx);
  
          return rc;
  }
  
  void
  device_pmf_unlock(device_t dev PMF_FN_ARGS)
  {
          pmf_private_t *pp = device_pmf_private(dev);
  
          KASSERT(pp->pp_nlock > 0);
          mutex_enter(&pp->pp_mtx);
          if (--pp->pp_nlock == 0)
                  pp->pp_holder = NULL;
          cv_signal(&pp->pp_cv);
          pmflock_debug_with_flags(dev, __func__, __LINE__ PMF_FN_CALL);
          mutex_exit(&pp->pp_mtx);
  }
  
  void *
  device_pmf_private(device_t dev)
  {
          return dev->dv_pmf_private;
  }
  
  void *
  device_pmf_bus_private(device_t dev)
  {
          return dev->dv_bus_private;
  }
  
  bool
  device_pmf_bus_suspend(device_t dev PMF_FN_ARGS)
  {
          if ((dev->dv_flags & DVF_BUS_SUSPENDED) != 0)
                  return true;
          if ((dev->dv_flags & DVF_CLASS_SUSPENDED) == 0 ||
              (dev->dv_flags & DVF_DRIVER_SUSPENDED) == 0)
                  return false;
          if (*dev->dv_bus_suspend != NULL &&
              !(*dev->dv_bus_suspend)(dev PMF_FN_CALL))
                  return false;
  
          dev->dv_flags |= DVF_BUS_SUSPENDED;
          return true;
  }
  
  bool
  device_pmf_bus_resume(device_t dev PMF_FN_ARGS)
  {
          if ((dev->dv_flags & DVF_BUS_SUSPENDED) == 0)
                  return true;
          if ((flags & PMF_F_SELF) != 0 && !device_is_self_suspended(dev))
                  return false;
          if (*dev->dv_bus_resume != NULL &&
              !(*dev->dv_bus_resume)(dev PMF_FN_CALL))
                  return false;
  
          dev->dv_flags &= ~DVF_BUS_SUSPENDED;
          return true;
  }
  
  bool
  device_pmf_bus_shutdown(device_t dev, int how)
  {
  
          if (*dev->dv_bus_shutdown != NULL &&
              !(*dev->dv_bus_shutdown)(dev, how))
                  return false;
          return true;
  }
  
  void
  device_pmf_bus_register(device_t dev, void *priv,
      bool (*suspend)(device_t PMF_FN_PROTO),
      bool (*resume)(device_t PMF_FN_PROTO),
      bool (*shutdown)(device_t, int), void (*deregister)(device_t))
  {
          dev->dv_bus_private = priv;
          dev->dv_bus_resume = resume;
          dev->dv_bus_suspend = suspend;
          dev->dv_bus_shutdown = shutdown;
          dev->dv_bus_deregister = deregister;
  }
  
  void
  device_pmf_bus_deregister(device_t dev)
  {
          if (dev->dv_bus_deregister == NULL)
                  return;
          (*dev->dv_bus_deregister)(dev);
          dev->dv_bus_private = NULL;
          dev->dv_bus_suspend = NULL;
          dev->dv_bus_resume = NULL;
          dev->dv_bus_deregister = NULL;
  }
  
  void *
  device_pmf_class_private(device_t dev)
  {
          return dev->dv_class_private;
  }
  
  bool
  device_pmf_class_suspend(device_t dev PMF_FN_ARGS)
  {
          if ((dev->dv_flags & DVF_CLASS_SUSPENDED) != 0)
                  return true;
          if (*dev->dv_class_suspend != NULL &&
              !(*dev->dv_class_suspend)(dev PMF_FN_CALL))
                  return false;
  
          dev->dv_flags |= DVF_CLASS_SUSPENDED;
          return true;
  }
  
  bool
  device_pmf_class_resume(device_t dev PMF_FN_ARGS)
  {
          if ((dev->dv_flags & DVF_CLASS_SUSPENDED) == 0)
                  return true;
          if ((dev->dv_flags & DVF_BUS_SUSPENDED) != 0 ||
              (dev->dv_flags & DVF_DRIVER_SUSPENDED) != 0)
                  return false;
          if (*dev->dv_class_resume != NULL &&
              !(*dev->dv_class_resume)(dev PMF_FN_CALL))
                  return false;
  
          dev->dv_flags &= ~DVF_CLASS_SUSPENDED;
          return true;
  }
  
  void
  device_pmf_class_register(device_t dev, void *priv,
      bool (*suspend)(device_t PMF_FN_PROTO),
      bool (*resume)(device_t PMF_FN_PROTO),
      void (*deregister)(device_t))
  {
          dev->dv_class_private = priv;
          dev->dv_class_suspend = suspend;
          dev->dv_class_resume = resume;
          dev->dv_class_deregister = deregister;
  }
  
  void
  device_pmf_class_deregister(device_t dev)
  {
          if (dev->dv_class_deregister == NULL)
                  return;
          (*dev->dv_class_deregister)(dev);
          dev->dv_class_private = NULL;
          dev->dv_class_suspend = NULL;
          dev->dv_class_resume = NULL;
          dev->dv_class_deregister = NULL;
  }
  
  bool
  device_active(device_t dev, devactive_t type)
  {
          size_t i;
  
          if (dev->dv_activity_count == 0)
                  return false;
  
          for (i = 0; i < dev->dv_activity_count; ++i) {
                  if (dev->dv_activity_handlers[i] == NULL)
                          break;
                  (*dev->dv_activity_handlers[i])(dev, type);
          }
  
          return true;
  }
  
  bool
  device_active_register(device_t dev, void (*handler)(device_t, devactive_t))
  {
          void (**new_handlers)(device_t, devactive_t);
          void (**old_handlers)(device_t, devactive_t);
          size_t i, old_size, new_size;
          int s;
  
          old_handlers = dev->dv_activity_handlers;
          old_size = dev->dv_activity_count;
  
          for (i = 0; i < old_size; ++i) {
                  KASSERT(old_handlers[i] != handler);
                  if (old_handlers[i] == NULL) {
                          old_handlers[i] = handler;
                          return true;
                  }
          }
  
          new_size = old_size + 4;
          new_handlers = kmem_alloc(sizeof(void *[new_size]), KM_SLEEP);
  
          memcpy(new_handlers, old_handlers, sizeof(void *[old_size]));
          new_handlers[old_size] = handler;
          memset(new_handlers + old_size + 1, 0,
              sizeof(int [new_size - (old_size+1)]));
  
          s = splhigh();
          dev->dv_activity_count = new_size;
          dev->dv_activity_handlers = new_handlers;
          splx(s);
  
          if (old_handlers != NULL)
                  kmem_free(old_handlers, sizeof(int [old_size]));
  
          return true;
  }
  
  void
  device_active_deregister(device_t dev, void (*handler)(device_t, devactive_t))
  {
          void (**old_handlers)(device_t, devactive_t);
          size_t i, old_size;
          int s;
  
          old_handlers = dev->dv_activity_handlers;
          old_size = dev->dv_activity_count;
  
          for (i = 0; i < old_size; ++i) {
                  if (old_handlers[i] == handler)
                          break;
                  if (old_handlers[i] == NULL)
                          return; /* XXX panic? */
          }
  
          if (i == old_size)
                  return; /* XXX panic? */
  
          for (; i < old_size - 1; ++i) {
                  if ((old_handlers[i] = old_handlers[i + 1]) != NULL)
                          continue;
  
                  if (i == 0) {
                          s = splhigh();
                          dev->dv_activity_count = 0;
                          dev->dv_activity_handlers = NULL;
                          splx(s);
                          kmem_free(old_handlers, sizeof(void *[old_size]));
                  }
                  return;
          }
          old_handlers[i] = NULL;
  }
  
  /*
   * Device Iteration
   *
   * deviter_t: a device iterator.  Holds state for a "walk" visiting
   *     each device_t's in the device tree.
   *
   * deviter_init(di, flags): initialize the device iterator `di'
   *     to "walk" the device tree.  deviter_next(di) will return
   *     the first device_t in the device tree, or NULL if there are
   *     no devices.
   *
   *     `flags' is one or more of DEVITER_F_RW, indicating that the
   *     caller intends to modify the device tree by calling
   *     config_detach(9) on devices in the order that the iterator
   *     returns them; DEVITER_F_ROOT_FIRST, asking for the devices
   *     nearest the "root" of the device tree to be returned, first;
   *     DEVITER_F_LEAVES_FIRST, asking for the devices furthest from
   *     the root of the device tree, first; and DEVITER_F_SHUTDOWN,
   *     indicating both that deviter_init() should not respect any
   *     locks on the device tree, and that deviter_next(di) may run
   *     in more than one LWP before the walk has finished.
   *
   *     Only one DEVITER_F_RW iterator may be in the device tree at
   *     once.
   *
   *     DEVITER_F_SHUTDOWN implies DEVITER_F_RW.
   *
   *     Results are undefined if the flags DEVITER_F_ROOT_FIRST and
   *     DEVITER_F_LEAVES_FIRST are used in combination.
   *
   * deviter_first(di, flags): initialize the device iterator `di'
   *     and return the first device_t in the device tree, or NULL
   *     if there are no devices.  The statement
   *
   *         dv = deviter_first(di);
   *
   *     is shorthand for
   *
   *         deviter_init(di);
   *         dv = deviter_next(di);
   *
   * deviter_next(di): return the next device_t in the device tree,
   *     or NULL if there are no more devices.  deviter_next(di)
   *     is undefined if `di' was not initialized with deviter_init() or
   *     deviter_first().
   *
   * deviter_release(di): stops iteration (subsequent calls to
   *     deviter_next() will return NULL), releases any locks and
   *     resources held by the device iterator.
   *
   * Device iteration does not return device_t's in any particular
   * order.  An iterator will never return the same device_t twice.
   * Device iteration is guaranteed to complete---i.e., if deviter_next(di)
   * is called repeatedly on the same `di', it will eventually return
   * NULL.  It is ok to attach/detach devices during device iteration.
   */
  void
  deviter_init(deviter_t *di, deviter_flags_t flags)
  {
          device_t dv;
          bool rw;
  
          mutex_enter(&alldevs_mtx);
          if ((flags & DEVITER_F_SHUTDOWN) != 0) {
                  flags |= DEVITER_F_RW;
                  alldevs_nwrite++;
                  alldevs_writer = NULL;
                  alldevs_nread = 0;
          } else {
                  rw = (flags & DEVITER_F_RW) != 0;
  
                  if (alldevs_nwrite > 0 && alldevs_writer == NULL)
                          ;
                  else while ((alldevs_nwrite != 0 && alldevs_writer != curlwp) ||
                         (rw && alldevs_nread != 0))
                          cv_wait(&alldevs_cv, &alldevs_mtx);
  
                  if (rw) {
                          if (alldevs_nwrite++ == 0)
                                  alldevs_writer = curlwp;
                  } else
                          alldevs_nread++;
          }
          mutex_exit(&alldevs_mtx);
  
          memset(di, 0, sizeof(*di));
  
          di->di_flags = flags;
  
          switch (di->di_flags & (DEVITER_F_LEAVES_FIRST|DEVITER_F_ROOT_FIRST)) {
          case DEVITER_F_LEAVES_FIRST:
                  TAILQ_FOREACH(dv, &alldevs, dv_list)
                          di->di_curdepth = MAX(di->di_curdepth, dv->dv_depth);
                  break;
          case DEVITER_F_ROOT_FIRST:
                  TAILQ_FOREACH(dv, &alldevs, dv_list)
                          di->di_maxdepth = MAX(di->di_maxdepth, dv->dv_depth);
                  break;
          default:
                  break;
          }
  
          deviter_reinit(di);
  }
  
  static void
  deviter_reinit(deviter_t *di)
  {
          if ((di->di_flags & DEVITER_F_RW) != 0)
                  di->di_prev = TAILQ_LAST(&alldevs, devicelist);
          else
                  di->di_prev = TAILQ_FIRST(&alldevs);
  }
  
  device_t
  deviter_first(deviter_t *di, deviter_flags_t flags)
  {
          deviter_init(di, flags);
          return deviter_next(di);
  }
  
  static device_t
  deviter_next1(deviter_t *di)
  {
          device_t dv;
  
          dv = di->di_prev;
  
          if (dv == NULL)
                  ;
          else if ((di->di_flags & DEVITER_F_RW) != 0)
                  di->di_prev = TAILQ_PREV(dv, devicelist, dv_list);
          else
                  di->di_prev = TAILQ_NEXT(dv, dv_list);
  
          return dv;
  }
  
  device_t
  deviter_next(deviter_t *di)
  {
          device_t dv = NULL;
  
          switch (di->di_flags & (DEVITER_F_LEAVES_FIRST|DEVITER_F_ROOT_FIRST)) {
          case 0:
                  return deviter_next1(di);
          case DEVITER_F_LEAVES_FIRST:
                  while (di->di_curdepth >= 0) {
                          if ((dv = deviter_next1(di)) == NULL) {
                                  di->di_curdepth--;
                                  deviter_reinit(di);
                          } else if (dv->dv_depth == di->di_curdepth)
                                  break;
                  }
                  return dv;
          case DEVITER_F_ROOT_FIRST:
                  while (di->di_curdepth <= di->di_maxdepth) {
                          if ((dv = deviter_next1(di)) == NULL) {
                                  di->di_curdepth++;
                                  deviter_reinit(di);
                          } else if (dv->dv_depth == di->di_curdepth)
                                  break;
                  }
                  return dv;
          default:
                  return NULL;
          }
  }
  
  void
  deviter_release(deviter_t *di)
  {
          bool rw = (di->di_flags & DEVITER_F_RW) != 0;
  
          mutex_enter(&alldevs_mtx);
          if (alldevs_nwrite > 0 && alldevs_writer == NULL)
                  --alldevs_nwrite;
          else {
  
                  if (rw) {
                          if (--alldevs_nwrite == 0)
                                  alldevs_writer = NULL;
                  } else
                          --alldevs_nread;
  
                  cv_signal(&alldevs_cv);
          }
          mutex_exit(&alldevs_mtx);
  }

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