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

     /* $NetBSD: subr_autoconf.c,v 1.89 2004/02/17 05:03:16 rtr 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 1.89 2004/02/17 05:03:16 rtr 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/reboot.h>
    #include <machine/limits.h>
    
    #include "opt_userconf.h"
    #ifdef USERCONF
    #include <sys/userconf.h>
    #endif
    
    /*
    * Autoconfiguration subroutines.
    */
   
   /*
    * 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;
   static struct cftable initcftable;
   
   /*
    * Database of device properties.
    */
   propdb_t dev_propdb;
   
   #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 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 *);
   
   /* Hooks to finalize configuration once all real devices have been found. */
   struct finalize_hook {
           TAILQ_ENTRY(finalize_hook) f_list;
           int (*f_func)(struct device *);
           struct device *f_dev;
   };
   static TAILQ_HEAD(, finalize_hook) config_finalize_list;
   static int config_finalize_done;
   
   /* list of all devices */
   struct devicelist alldevs;
   
   __volatile int config_pending;          /* semaphore for mountroot */
   
   #define STREQ(s1, s2)                   \
           (*(s1) == *(s2) && strcmp((s1), (s2)) == 0)
   
   static int config_initialized;          /* config_init() has been called. */
   
   static int config_do_twiddle;
   
   /*
    * 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;
   
           /* 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);
                   }
           }
   
           TAILQ_INIT(&allcftables);
           initcftable.ct_cfdata = cfdata;
           TAILQ_INSERT_TAIL(&allcftables, &initcftable, ct_list);
   
           TAILQ_INIT(&deferred_config_queue);
           TAILQ_INIT(&interrupt_config_queue);
           TAILQ_INIT(&config_finalize_list);
           TAILQ_INIT(&alldevs); 
   
           config_initialized = 1;
   }
   
   /*
    * Configure the system's hardware.
    */
   void
   configure(void)
   {
           int errcnt;
   
           /* Initialize data structures. */
           config_init();
   
           /* Initialize the device property database. */
           dev_propdb = propdb_create("device properties");
           if (dev_propdb == NULL)
                   panic("unable to create device property database");
   
   #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();
   
           /*
            * 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);
   
           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");
                   }
           }
   }
   
   /*
    * 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;
           struct device *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, struct cfdata *cf)
   {
           int pri;
   
           if (m->fn != NULL)
                   pri = (*m->fn)(m->parent, cf, m->aux);
           else {
                   struct cfattach *ca;
   
                   ca = config_cfattach_lookup(cf->cf_name, cf->cf_atname);
                   if (ca == NULL) {
                           /* No attachment for this entry, oh well. */
                           return;
                   }
                   if (ca->ca_match == NULL) {
                           panic("mapply: no match function for '%s' attachment "
                               "of '%s'", cf->cf_atname, cf->cf_name);
                   }
                   pri = (*ca->ca_match)(m->parent, cf, m->aux);
           }
           if (pri > m->pri) {
                   m->match = cf;
                   m->pri = pri;
           }
   }
   
   /*
    * Determine if `parent' is a potential parent for a device spec based
    * on `cfp'.
    */
   static int
   cfparent_match(struct device *parent, const struct cfparent *cfp)
   {
           struct cfdriver *pcd;
           const char * const *cpp;
           const char *cp;
   
           /* 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 (pcd->cd_attrs == NULL)
                   return (0);     /* no interface attributes -> no children */
           for (cpp = pcd->cd_attrs; (cp = *cpp) != NULL; cpp++) {
                   if (STREQ(cp, cfp->cfp_iattr)) {
                           /* Match. */
                           break;
                   }
           }
           if (cp == NULL)
                   return (0);     /* doesn't carry the req'd attribute */
   
           /*
            * 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);
   }
   
   /*
    * Invoke the "match" routine for a cfdata entry on behalf of
    * an external caller, usually a "submatch" routine.
    */
   int
   config_match(struct device *parent, struct cfdata *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).
    */
   struct cfdata *
   config_search(cfmatch_t fn, struct device *parent, void *aux)
   {
           struct cftable *ct;
           struct cfdata *cf;
           struct matchinfo m;
   
           KASSERT(config_initialized);
   
           m.fn = fn;
           m.parent = parent;
           m.aux = aux;
           m.match = NULL;
           m.pri = 0;
   
           TAILQ_FOREACH(ct, &allcftables, ct_list) {
                   for (cf = ct->ct_cfdata; cf->cf_name; 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;
                           if (cf->cf_fstate == FSTATE_DNOTFOUND ||
                               cf->cf_fstate == FSTATE_DSTAR)
                                   continue;
                           if (cfparent_match(parent, cf->cf_pspec))
                                   mapply(&m, cf);
                   }
           }
           return (m.match);
   }
   
   /*
    * 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.
    */
   struct cfdata *
   config_rootsearch(cfmatch_t fn, const char *rootname, void *aux)
   {
           struct cfdata *cf;
           const 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_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.
    */
   struct device *
   config_found_sm(struct device *parent, void *aux, cfprint_t print,
       cfmatch_t submatch)
   {
           struct cfdata *cf;
   
           if ((cf = config_search(submatch, parent, aux)) != NULL)
                   return (config_attach(parent, cf, aux, print));
           if (print) {
                   if (config_do_twiddle)
                           twiddle();
                   aprint_normal("%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;
   
           if ((cf = config_rootsearch((cfmatch_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.
    */
   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(struct device *parent, struct cfdata *cf, void *aux,
           cfprint_t print)
   {
           struct device *dev;
           struct cftable *ct;
           struct cfdriver *cd;
           struct cfattach *ca;
           size_t lname, lunit;
           const char *xunit;
           int myunit;
           char num[10];
   
           cd = config_cfdriver_lookup(cf->cf_name);
           KASSERT(cd != NULL);
   
           ca = config_cfattach_lookup_cd(cd, cf->cf_atname);
           KASSERT(ca != NULL);
   
           if (ca->ca_devsize < sizeof(struct device))
                   panic("config_attach");
   
   #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;
                   KASSERT(cf->cf_fstate == FSTATE_NOTFOUND);
                   cf->cf_fstate = FSTATE_FOUND;
           }
   #else
           myunit = cf->cf_unit;
           if (cf->cf_fstate == FSTATE_STAR)
                   cf->cf_unit++;
           else {
                   KASSERT(cf->cf_fstate == FSTATE_NOTFOUND);
                   cf->cf_fstate = FSTATE_FOUND;
           }
   #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_attach: device name too long");
   
           /* get memory for all device vars */
           dev = (struct device *)malloc(ca->ca_devsize, M_DEVBUF,
               cold ? M_NOWAIT : M_WAITOK);
           if (!dev)
               panic("config_attach: memory allocation for device softc failed");
           memset(dev, 0, ca->ca_devsize);
           TAILQ_INSERT_TAIL(&alldevs, dev, dv_list);      /* link up */
           dev->dv_class = cd->cd_class;
           dev->dv_cfdata = cf;
           dev->dv_cfdriver = cd;
           dev->dv_cfattach = ca;
           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 (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)", dev->dv_xname);
                   aprint_normal("%s (root)", dev->dv_xname);
           } else {
                   aprint_naive("%s at %s", dev->dv_xname, parent->dv_xname);
                   aprint_normal("%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.
            */
           TAILQ_FOREACH(ct, &allcftables, ct_list) {
                   for (cf = ct->ct_cfdata; cf->cf_name; cf++) {
                           if (STREQ(cf->cf_name, cd->cd_name) &&
                               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
           (*ca->ca_attach)(parent, dev, aux);
           config_process_deferred(&deferred_config_queue, dev);
           return (dev);
   }
   
   /*
    * 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.
    */
   struct device *
   config_attach_pseudo(const char *name, int unit)
   {
           struct device *dev;
           struct cfdriver *cd;
           struct cfattach *ca;
           size_t lname, lunit;
           const char *xunit;
           int myunit;
           char num[10];
   
           cd = config_cfdriver_lookup(name);
           if (cd == NULL)
                   return (NULL);
   
           ca = config_cfattach_lookup_cd(cd, name);
           if (ca == NULL)
                   return (NULL);
   
           if (ca->ca_devsize < sizeof(struct device))
                   panic("config_attach_pseudo");
   
           if (unit == DVUNIT_ANY) {
                   for (myunit = 0; myunit < cd->cd_ndevs; myunit++)
                           if (cd->cd_devs[myunit] == NULL)
                                   break;
                   /*
                    * myunit is now the unit of the first NULL device pointer.
                    */
           } else {
                   myunit = unit;
                   if (myunit < cd->cd_ndevs && cd->cd_devs[myunit] != NULL)
                           return (NULL);
           }
   
           /* 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_pseudo: device name too long");
   
           /* get memory for all device vars */
           dev = (struct device *)malloc(ca->ca_devsize, M_DEVBUF,
               cold ? M_NOWAIT : M_WAITOK);
           if (!dev)
                   panic("config_attach_pseudo: memory allocation for device "
                       "softc failed");
           memset(dev, 0, ca->ca_devsize);
           TAILQ_INSERT_TAIL(&alldevs, dev, dv_list);      /* link up */
           dev->dv_class = cd->cd_class;
           dev->dv_cfdata = NULL;
           dev->dv_cfdriver = cd;
           dev->dv_cfattach = ca;
           dev->dv_unit = myunit;
           memcpy(dev->dv_xname, cd->cd_name, lname);
           memcpy(dev->dv_xname + lname, xunit, lunit);
           dev->dv_parent = ROOT;
           dev->dv_flags = DVF_ACTIVE;     /* always initially active */
   
           /* put this device in the devices array */
           config_makeroom(dev->dv_unit, cd);
           if (cd->cd_devs[dev->dv_unit])
                   panic("config_attach_pseudo: duplicate %s", dev->dv_xname);
           cd->cd_devs[dev->dv_unit] = dev;
   
   #if 0   /* XXXJRT not yet */
   #ifdef __HAVE_DEVICE_REGISTER
           device_register(dev, NULL);     /* like a root node */
   #endif
   #endif
           (*ca->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(struct device *dev, int flags)
   {
           struct cftable *ct;
           struct cfdata *cf;
           const struct cfattach *ca;
           struct cfdriver *cd;
   #ifdef DIAGNOSTIC
           struct device *d;
   #endif
           int rv = 0, i;
   
   #ifdef DIAGNOSTIC
           if (dev->dv_cfdata != NULL &&
               dev->dv_cfdata->cf_fstate != FSTATE_FOUND &&
               dev->dv_cfdata->cf_fstate != FSTATE_STAR)
                   panic("config_detach: bad device fstate");
   #endif
           cd = dev->dv_cfdriver;
           KASSERT(cd != NULL);
   
           ca = dev->dv_cfattach;
           KASSERT(ca != NULL);
   
           /*
            * 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.
            */
          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 */
                          }
                  }
          }
  
          /*
           * Unlink from device list.
           */
          TAILQ_REMOVE(&alldevs, dev, dv_list);
  
          /*
           * Remove from cfdriver's array, tell the world (unless it was
           * a pseudo-device), and free softc.
           */
          cd->cd_devs[dev->dv_unit] = NULL;
          if (dev->dv_cfdata != NULL && (flags & DETACH_QUIET) == 0)
                  aprint_normal("%s detached\n", dev->dv_xname);
          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)
  {
          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(struct device *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(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);
  }
  
  /*
   * 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(struct device *dev, int (*fn)(struct device *))
  {
          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 = malloc(sizeof(*f), M_TEMP, M_WAITOK);
          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;
          int rv;
  
          /* 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);
                  free(f, M_TEMP);
          }
  }
  

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