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

     /*
      * Copyright (c) 1997,1998 Doug Rabson
      * All rights reserved.
      *
      * Redistribution and use in source and binary forms, with or without
      * modification, are permitted provided that the following conditions
      * are met:
      * 1. Redistributions of source code must retain the above copyright
      *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     *
     * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
     * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     * SUCH DAMAGE.
     *
     * $FreeBSD: src/sys/kern/subr_bus.c,v 1.54.2.9 2002/10/10 15:13:32 jhb Exp $
     */
    
    #include "opt_bus.h"
    
    #include <sys/param.h>
    #include <sys/queue.h>
    #include <sys/malloc.h>
    #include <sys/kernel.h>
    #include <sys/module.h>
    #include <sys/kobj.h>
    #include <sys/bus_private.h>
    #include <sys/sysctl.h>
    #include <sys/systm.h>
    #include <sys/bus.h>
    #include <sys/rman.h>
    #include <sys/device.h>
    #include <sys/lock.h>
    #include <sys/conf.h>
    #include <sys/uio.h>
    #include <sys/filio.h>
    #include <sys/event.h>
    #include <sys/signalvar.h>
    #include <sys/machintr.h>
    
    #include <machine/stdarg.h>     /* for device_printf() */
    
    #include <sys/thread2.h>
    #include <sys/mplock2.h>
    
    SYSCTL_NODE(_hw, OID_AUTO, bus, CTLFLAG_RW, NULL, NULL);
    
    MALLOC_DEFINE(M_BUS, "bus", "Bus data structures");
    
    #ifdef BUS_DEBUG
    #define PDEBUG(a)       (kprintf("%s:%d: ", __func__, __LINE__), kprintf a, kprintf("\n"))
    #define DEVICENAME(d)   ((d)? device_get_name(d): "no device")
    #define DRIVERNAME(d)   ((d)? d->name : "no driver")
    #define DEVCLANAME(d)   ((d)? d->name : "no devclass")
    
    /* Produce the indenting, indent*2 spaces plus a '.' ahead of that to 
     * prevent syslog from deleting initial spaces
     */
    #define indentprintf(p) do { int iJ; kprintf("."); for (iJ=0; iJ<indent; iJ++) kprintf("  "); kprintf p ; } while(0)
    
    static void     print_device_short(device_t dev, int indent);
    static void     print_device(device_t dev, int indent);
    void            print_device_tree_short(device_t dev, int indent);
    void            print_device_tree(device_t dev, int indent);
    static void     print_driver_short(driver_t *driver, int indent);
    static void     print_driver(driver_t *driver, int indent);
    static void     print_driver_list(driver_list_t drivers, int indent);
    static void     print_devclass_short(devclass_t dc, int indent);
    static void     print_devclass(devclass_t dc, int indent);
    void            print_devclass_list_short(void);
    void            print_devclass_list(void);
    
    #else
    /* Make the compiler ignore the function calls */
    #define PDEBUG(a)                       /* nop */
    #define DEVICENAME(d)                   /* nop */
    #define DRIVERNAME(d)                   /* nop */
    #define DEVCLANAME(d)                   /* nop */
    
    #define print_device_short(d,i)         /* nop */
    #define print_device(d,i)               /* nop */
    #define print_device_tree_short(d,i)    /* nop */
    #define print_device_tree(d,i)          /* nop */
    #define print_driver_short(d,i)         /* nop */
    #define print_driver(d,i)               /* nop */
    #define print_driver_list(d,i)          /* nop */
    #define print_devclass_short(d,i)       /* nop */
    #define print_devclass(d,i)             /* nop */
    #define print_devclass_list_short()     /* nop */
   #define print_devclass_list()           /* nop */
   #endif
   
   static void     device_attach_async(device_t dev);
   static void     device_attach_thread(void *arg);
   static int      device_doattach(device_t dev);
   
   static int do_async_attach = 0;
   static int numasyncthreads;
   TUNABLE_INT("kern.do_async_attach", &do_async_attach);
   
   /*
    * /dev/devctl implementation
    */
   
   /*
    * This design allows only one reader for /dev/devctl.  This is not desirable
    * in the long run, but will get a lot of hair out of this implementation.
    * Maybe we should make this device a clonable device.
    *
    * Also note: we specifically do not attach a device to the device_t tree
    * to avoid potential chicken and egg problems.  One could argue that all
    * of this belongs to the root node.  One could also further argue that the
    * sysctl interface that we have not might more properly be an ioctl
    * interface, but at this stage of the game, I'm not inclined to rock that
    * boat.
    *
    * I'm also not sure that the SIGIO support is done correctly or not, as
    * I copied it from a driver that had SIGIO support that likely hasn't been
    * tested since 3.4 or 2.2.8!
    */
   
   static int sysctl_devctl_disable(SYSCTL_HANDLER_ARGS);
   static int devctl_disable = 0;
   TUNABLE_INT("hw.bus.devctl_disable", &devctl_disable);
   SYSCTL_PROC(_hw_bus, OID_AUTO, devctl_disable, CTLTYPE_INT | CTLFLAG_RW, 0, 0,
       sysctl_devctl_disable, "I", "devctl disable");
   
   static d_open_t         devopen;
   static d_close_t        devclose;
   static d_read_t         devread;
   static d_ioctl_t        devioctl;
   static d_kqfilter_t     devkqfilter;
   
   static struct dev_ops devctl_ops = {
           { "devctl", 0, 0 },
           .d_open =       devopen,
           .d_close =      devclose,
           .d_read =       devread,
           .d_ioctl =      devioctl,
           .d_kqfilter =   devkqfilter
   };
   
   struct dev_event_info
   {
           char *dei_data;
           TAILQ_ENTRY(dev_event_info) dei_link;
   };
   
   TAILQ_HEAD(devq, dev_event_info);
   
   static struct dev_softc
   {
           int     inuse;
           int     nonblock;
           struct lock lock;
           struct kqinfo kq;
           struct devq devq;
           struct proc *async_proc;
   } devsoftc;
   
   static void
   devinit(void)
   {
           make_dev(&devctl_ops, 0, UID_ROOT, GID_WHEEL, 0600, "devctl");
           lockinit(&devsoftc.lock, "dev mtx", 0, 0);
           TAILQ_INIT(&devsoftc.devq);
   }
   
   static int
   devopen(struct dev_open_args *ap)
   {
           if (devsoftc.inuse)
                   return (EBUSY);
           /* move to init */
           devsoftc.inuse = 1;
           devsoftc.nonblock = 0;
           devsoftc.async_proc = NULL;
           return (0);
   }
   
   static int
   devclose(struct dev_close_args *ap)
   {
           devsoftc.inuse = 0;
           lockmgr(&devsoftc.lock, LK_EXCLUSIVE);
           wakeup(&devsoftc);
           lockmgr(&devsoftc.lock, LK_RELEASE);
   
           return (0);
   }
   
   /*
    * The read channel for this device is used to report changes to
    * userland in realtime.  We are required to free the data as well as
    * the n1 object because we allocate them separately.  Also note that
    * we return one record at a time.  If you try to read this device a
    * character at a time, you will lose the rest of the data.  Listening
    * programs are expected to cope.
    */
   static int
   devread(struct dev_read_args *ap)
   {
           struct uio *uio = ap->a_uio;
           struct dev_event_info *n1;
           int rv;
   
           lockmgr(&devsoftc.lock, LK_EXCLUSIVE);
           while (TAILQ_EMPTY(&devsoftc.devq)) {
                   if (devsoftc.nonblock) {
                           lockmgr(&devsoftc.lock, LK_RELEASE);
                           return (EAGAIN);
                   }
                   tsleep_interlock(&devsoftc, PCATCH);
                   lockmgr(&devsoftc.lock, LK_RELEASE);
                   rv = tsleep(&devsoftc, PCATCH | PINTERLOCKED, "devctl", 0);
                   lockmgr(&devsoftc.lock, LK_EXCLUSIVE);
                   if (rv) {
                           /*
                            * Need to translate ERESTART to EINTR here? -- jake
                            */
                           lockmgr(&devsoftc.lock, LK_RELEASE);
                           return (rv);
                   }
           }
           n1 = TAILQ_FIRST(&devsoftc.devq);
           TAILQ_REMOVE(&devsoftc.devq, n1, dei_link);
           lockmgr(&devsoftc.lock, LK_RELEASE);
           rv = uiomove(n1->dei_data, strlen(n1->dei_data), uio);
           kfree(n1->dei_data, M_BUS);
           kfree(n1, M_BUS);
           return (rv);
   }
   
   static  int
   devioctl(struct dev_ioctl_args *ap)
   {
           switch (ap->a_cmd) {
   
           case FIONBIO:
                   if (*(int*)ap->a_data)
                           devsoftc.nonblock = 1;
                   else
                           devsoftc.nonblock = 0;
                   return (0);
           case FIOASYNC:
                   if (*(int*)ap->a_data)
                           devsoftc.async_proc = curproc;
                   else
                           devsoftc.async_proc = NULL;
                   return (0);
   
                   /* (un)Support for other fcntl() calls. */
           case FIOCLEX:
           case FIONCLEX:
           case FIONREAD:
           case FIOSETOWN:
           case FIOGETOWN:
           default:
                   break;
           }
           return (ENOTTY);
   }
   
   static void dev_filter_detach(struct knote *);
   static int dev_filter_read(struct knote *, long);
   
   static struct filterops dev_filtops =
           { FILTEROP_ISFD, NULL, dev_filter_detach, dev_filter_read };
   
   static int
   devkqfilter(struct dev_kqfilter_args *ap)
   {
           struct knote *kn = ap->a_kn;
           struct klist *klist;
   
           ap->a_result = 0;
           lockmgr(&devsoftc.lock, LK_EXCLUSIVE);
   
           switch (kn->kn_filter) {
           case EVFILT_READ:
                   kn->kn_fop = &dev_filtops;
                   break;
           default:
                   ap->a_result = EOPNOTSUPP;
                   lockmgr(&devsoftc.lock, LK_RELEASE);
                   return (0);
           }
   
           klist = &devsoftc.kq.ki_note;
           knote_insert(klist, kn);
   
           lockmgr(&devsoftc.lock, LK_RELEASE);
   
           return (0);
   }
   
   static void
   dev_filter_detach(struct knote *kn)
   {
           struct klist *klist;
   
           lockmgr(&devsoftc.lock, LK_EXCLUSIVE);
           klist = &devsoftc.kq.ki_note;
           knote_remove(klist, kn);
           lockmgr(&devsoftc.lock, LK_RELEASE);
   }
   
   static int
   dev_filter_read(struct knote *kn, long hint)
   {
           int ready = 0;
   
           lockmgr(&devsoftc.lock, LK_EXCLUSIVE);
           if (!TAILQ_EMPTY(&devsoftc.devq))
                   ready = 1;
           lockmgr(&devsoftc.lock, LK_RELEASE);
   
           return (ready);
   }
   
   
   /**
    * @brief Return whether the userland process is running
    */
   boolean_t
   devctl_process_running(void)
   {
           return (devsoftc.inuse == 1);
   }
   
   /**
    * @brief Queue data to be read from the devctl device
    *
    * Generic interface to queue data to the devctl device.  It is
    * assumed that @p data is properly formatted.  It is further assumed
    * that @p data is allocated using the M_BUS malloc type.
    */
   void
   devctl_queue_data(char *data)
   {
           struct dev_event_info *n1 = NULL;
           struct proc *p;
   
           n1 = kmalloc(sizeof(*n1), M_BUS, M_NOWAIT);
           if (n1 == NULL)
                   return;
           n1->dei_data = data;
           lockmgr(&devsoftc.lock, LK_EXCLUSIVE);
           TAILQ_INSERT_TAIL(&devsoftc.devq, n1, dei_link);
           wakeup(&devsoftc);
           lockmgr(&devsoftc.lock, LK_RELEASE);
           get_mplock();   /* XXX */
           KNOTE(&devsoftc.kq.ki_note, 0);
           rel_mplock();   /* XXX */
           p = devsoftc.async_proc;
           if (p != NULL)
                   ksignal(p, SIGIO);
   }
   
   /**
    * @brief Send a 'notification' to userland, using standard ways
    */
   void
   devctl_notify(const char *system, const char *subsystem, const char *type,
       const char *data)
   {
           int len = 0;
           char *msg;
   
           if (system == NULL)
                   return;         /* BOGUS!  Must specify system. */
           if (subsystem == NULL)
                   return;         /* BOGUS!  Must specify subsystem. */
           if (type == NULL)
                   return;         /* BOGUS!  Must specify type. */
           len += strlen(" system=") + strlen(system);
           len += strlen(" subsystem=") + strlen(subsystem);
           len += strlen(" type=") + strlen(type);
           /* add in the data message plus newline. */
           if (data != NULL)
                   len += strlen(data);
           len += 3;       /* '!', '\n', and NUL */
           msg = kmalloc(len, M_BUS, M_NOWAIT);
           if (msg == NULL)
                   return;         /* Drop it on the floor */
           if (data != NULL)
                   ksnprintf(msg, len, "!system=%s subsystem=%s type=%s %s\n",
                       system, subsystem, type, data);
           else
                   ksnprintf(msg, len, "!system=%s subsystem=%s type=%s\n",
                       system, subsystem, type);
           devctl_queue_data(msg);
   }
   
   /*
    * Common routine that tries to make sending messages as easy as possible.
    * We allocate memory for the data, copy strings into that, but do not
    * free it unless there's an error.  The dequeue part of the driver should
    * free the data.  We don't send data when the device is disabled.  We do
    * send data, even when we have no listeners, because we wish to avoid
    * races relating to startup and restart of listening applications.
    *
    * devaddq is designed to string together the type of event, with the
    * object of that event, plus the plug and play info and location info
    * for that event.  This is likely most useful for devices, but less
    * useful for other consumers of this interface.  Those should use
    * the devctl_queue_data() interface instead.
    */
   static void
   devaddq(const char *type, const char *what, device_t dev)
   {
           char *data = NULL;
           char *loc = NULL;
           char *pnp = NULL;
           const char *parstr;
   
           if (devctl_disable)
                   return;
           data = kmalloc(1024, M_BUS, M_NOWAIT);
           if (data == NULL)
                   goto bad;
   
           /* get the bus specific location of this device */
           loc = kmalloc(1024, M_BUS, M_NOWAIT);
           if (loc == NULL)
                   goto bad;
           *loc = '\0';
           bus_child_location_str(dev, loc, 1024);
   
           /* Get the bus specific pnp info of this device */
           pnp = kmalloc(1024, M_BUS, M_NOWAIT);
           if (pnp == NULL)
                   goto bad;
           *pnp = '\0';
           bus_child_pnpinfo_str(dev, pnp, 1024);
   
           /* Get the parent of this device, or / if high enough in the tree. */
           if (device_get_parent(dev) == NULL)
                   parstr = ".";   /* Or '/' ? */
           else
                   parstr = device_get_nameunit(device_get_parent(dev));
           /* String it all together. */
           ksnprintf(data, 1024, "%s%s at %s %s on %s\n", type, what, loc, pnp,
             parstr);
           kfree(loc, M_BUS);
           kfree(pnp, M_BUS);
           devctl_queue_data(data);
           return;
   bad:
           kfree(pnp, M_BUS);
           kfree(loc, M_BUS);
           kfree(data, M_BUS);
           return;
   }
   
   /*
    * A device was added to the tree.  We are called just after it successfully
    * attaches (that is, probe and attach success for this device).  No call
    * is made if a device is merely parented into the tree.  See devnomatch
    * if probe fails.  If attach fails, no notification is sent (but maybe
    * we should have a different message for this).
    */
   static void
   devadded(device_t dev)
   {
           char *pnp = NULL;
           char *tmp = NULL;
   
           pnp = kmalloc(1024, M_BUS, M_NOWAIT);
           if (pnp == NULL)
                   goto fail;
           tmp = kmalloc(1024, M_BUS, M_NOWAIT);
           if (tmp == NULL)
                   goto fail;
           *pnp = '\0';
           bus_child_pnpinfo_str(dev, pnp, 1024);
           ksnprintf(tmp, 1024, "%s %s", device_get_nameunit(dev), pnp);
           devaddq("+", tmp, dev);
   fail:
           if (pnp != NULL)
                   kfree(pnp, M_BUS);
           if (tmp != NULL)
                   kfree(tmp, M_BUS);
           return;
   }
   
   /*
    * A device was removed from the tree.  We are called just before this
    * happens.
    */
   static void
   devremoved(device_t dev)
   {
           char *pnp = NULL;
           char *tmp = NULL;
   
           pnp = kmalloc(1024, M_BUS, M_NOWAIT);
           if (pnp == NULL)
                   goto fail;
           tmp = kmalloc(1024, M_BUS, M_NOWAIT);
           if (tmp == NULL)
                   goto fail;
           *pnp = '\0';
           bus_child_pnpinfo_str(dev, pnp, 1024);
           ksnprintf(tmp, 1024, "%s %s", device_get_nameunit(dev), pnp);
           devaddq("-", tmp, dev);
   fail:
           if (pnp != NULL)
                   kfree(pnp, M_BUS);
           if (tmp != NULL)
                   kfree(tmp, M_BUS);
           return;
   }
   
   /*
    * Called when there's no match for this device.  This is only called
    * the first time that no match happens, so we don't keep getitng this
    * message.  Should that prove to be undesirable, we can change it.
    * This is called when all drivers that can attach to a given bus
    * decline to accept this device.  Other errrors may not be detected.
    */
   static void
   devnomatch(device_t dev)
   {
           devaddq("?", "", dev);
   }
   
   static int
   sysctl_devctl_disable(SYSCTL_HANDLER_ARGS)
   {
           struct dev_event_info *n1;
           int dis, error;
   
           dis = devctl_disable;
           error = sysctl_handle_int(oidp, &dis, 0, req);
           if (error || !req->newptr)
                   return (error);
           lockmgr(&devsoftc.lock, LK_EXCLUSIVE);
           devctl_disable = dis;
           if (dis) {
                   while (!TAILQ_EMPTY(&devsoftc.devq)) {
                           n1 = TAILQ_FIRST(&devsoftc.devq);
                           TAILQ_REMOVE(&devsoftc.devq, n1, dei_link);
                           kfree(n1->dei_data, M_BUS);
                           kfree(n1, M_BUS);
                   }
           }
           lockmgr(&devsoftc.lock, LK_RELEASE);
           return (0);
   }
   
   /* End of /dev/devctl code */
   
   TAILQ_HEAD(,device)     bus_data_devices;
   static int bus_data_generation = 1;
   
   kobj_method_t null_methods[] = {
           { 0, 0 }
   };
   
   DEFINE_CLASS(null, null_methods, 0);
   
   /*
    * Devclass implementation
    */
   
   static devclass_list_t devclasses = TAILQ_HEAD_INITIALIZER(devclasses);
   
   static devclass_t
   devclass_find_internal(const char *classname, const char *parentname,
                          int create)
   {
           devclass_t dc;
   
           PDEBUG(("looking for %s", classname));
           if (classname == NULL)
                   return(NULL);
   
           TAILQ_FOREACH(dc, &devclasses, link)
                   if (!strcmp(dc->name, classname))
                           break;
   
           if (create && !dc) {
                   PDEBUG(("creating %s", classname));
                   dc = kmalloc(sizeof(struct devclass) + strlen(classname) + 1,
                               M_BUS, M_INTWAIT | M_ZERO);
                   dc->parent = NULL;
                   dc->name = (char*) (dc + 1);
                   strcpy(dc->name, classname);
                   dc->devices = NULL;
                   dc->maxunit = 0;
                   TAILQ_INIT(&dc->drivers);
                   TAILQ_INSERT_TAIL(&devclasses, dc, link);
   
                   bus_data_generation_update();
   
           }
   
           /*
            * If a parent class is specified, then set that as our parent so
            * that this devclass will support drivers for the parent class as
            * well.  If the parent class has the same name don't do this though
            * as it creates a cycle that can trigger an infinite loop in
            * device_probe_child() if a device exists for which there is no
            * suitable driver.
            */
           if (parentname && dc && !dc->parent &&
               strcmp(classname, parentname) != 0)
                   dc->parent = devclass_find_internal(parentname, NULL, FALSE);
   
           return(dc);
   }
   
   devclass_t
   devclass_create(const char *classname)
   {
           return(devclass_find_internal(classname, NULL, TRUE));
   }
   
   devclass_t
   devclass_find(const char *classname)
   {
           return(devclass_find_internal(classname, NULL, FALSE));
   }
   
   device_t
   devclass_find_unit(const char *classname, int unit)
   {
           devclass_t dc;
   
           if ((dc = devclass_find(classname)) != NULL)
               return(devclass_get_device(dc, unit));
           return (NULL);
   }
   
   int
   devclass_add_driver(devclass_t dc, driver_t *driver)
   {
           driverlink_t dl;
           device_t dev;
           int i;
   
           PDEBUG(("%s", DRIVERNAME(driver)));
   
           dl = kmalloc(sizeof *dl, M_BUS, M_INTWAIT | M_ZERO);
   
           /*
            * Compile the driver's methods. Also increase the reference count
            * so that the class doesn't get freed when the last instance
            * goes. This means we can safely use static methods and avoids a
            * double-free in devclass_delete_driver.
            */
           kobj_class_instantiate(driver);
   
           /*
            * Make sure the devclass which the driver is implementing exists.
            */
           devclass_find_internal(driver->name, NULL, TRUE);
   
           dl->driver = driver;
           TAILQ_INSERT_TAIL(&dc->drivers, dl, link);
   
           /*
            * Call BUS_DRIVER_ADDED for any existing busses in this class,
            * but only if the bus has already been attached (otherwise we
            * might probe too early).
            *
            * This is what will cause a newly loaded module to be associated
            * with hardware.  bus_generic_driver_added() is typically what ends
            * up being called.
            */
           for (i = 0; i < dc->maxunit; i++) {
                   if ((dev = dc->devices[i]) != NULL) {
                           if (dev->state >= DS_ATTACHED)
                                   BUS_DRIVER_ADDED(dev, driver);
                   }
           }
   
           bus_data_generation_update();
           return(0);
   }
   
   int
   devclass_delete_driver(devclass_t busclass, driver_t *driver)
   {
           devclass_t dc = devclass_find(driver->name);
           driverlink_t dl;
           device_t dev;
           int i;
           int error;
   
           PDEBUG(("%s from devclass %s", driver->name, DEVCLANAME(busclass)));
   
           if (!dc)
                   return(0);
   
           /*
            * Find the link structure in the bus' list of drivers.
            */
           TAILQ_FOREACH(dl, &busclass->drivers, link)
                   if (dl->driver == driver)
                           break;
   
           if (!dl) {
                   PDEBUG(("%s not found in %s list", driver->name, busclass->name));
                   return(ENOENT);
           }
   
           /*
            * Disassociate from any devices.  We iterate through all the
            * devices in the devclass of the driver and detach any which are
            * using the driver and which have a parent in the devclass which
            * we are deleting from.
            *
            * Note that since a driver can be in multiple devclasses, we
            * should not detach devices which are not children of devices in
            * the affected devclass.
            */
           for (i = 0; i < dc->maxunit; i++)
                   if (dc->devices[i]) {
                           dev = dc->devices[i];
                           if (dev->driver == driver && dev->parent &&
                               dev->parent->devclass == busclass) {
                                   if ((error = device_detach(dev)) != 0)
                                           return(error);
                                   device_set_driver(dev, NULL);
                           }
                   }
   
           TAILQ_REMOVE(&busclass->drivers, dl, link);
           kfree(dl, M_BUS);
   
           kobj_class_uninstantiate(driver);
   
           bus_data_generation_update();
           return(0);
   }
   
   static driverlink_t
   devclass_find_driver_internal(devclass_t dc, const char *classname)
   {
           driverlink_t dl;
   
           PDEBUG(("%s in devclass %s", classname, DEVCLANAME(dc)));
   
           TAILQ_FOREACH(dl, &dc->drivers, link)
                   if (!strcmp(dl->driver->name, classname))
                           return(dl);
   
           PDEBUG(("not found"));
           return(NULL);
   }
   
   kobj_class_t
   devclass_find_driver(devclass_t dc, const char *classname)
   {
           driverlink_t dl;
   
           dl = devclass_find_driver_internal(dc, classname);
           if (dl)
                   return(dl->driver);
           else
                   return(NULL);
   }
   
   const char *
   devclass_get_name(devclass_t dc)
   {
           return(dc->name);
   }
   
   device_t
   devclass_get_device(devclass_t dc, int unit)
   {
           if (dc == NULL || unit < 0 || unit >= dc->maxunit)
                   return(NULL);
           return(dc->devices[unit]);
   }
   
   void *
   devclass_get_softc(devclass_t dc, int unit)
   {
           device_t dev;
   
           dev = devclass_get_device(dc, unit);
           if (!dev)
                   return(NULL);
   
           return(device_get_softc(dev));
   }
   
   int
   devclass_get_devices(devclass_t dc, device_t **devlistp, int *devcountp)
   {
           int i;
           int count;
           device_t *list;
       
           count = 0;
           for (i = 0; i < dc->maxunit; i++)
                   if (dc->devices[i])
                           count++;
   
           list = kmalloc(count * sizeof(device_t), M_TEMP, M_INTWAIT | M_ZERO);
   
           count = 0;
           for (i = 0; i < dc->maxunit; i++)
                   if (dc->devices[i]) {
                           list[count] = dc->devices[i];
                           count++;
                   }
   
           *devlistp = list;
           *devcountp = count;
   
           return(0);
   }
   
   /**
    * @brief Get a list of drivers in the devclass
    *
    * An array containing a list of pointers to all the drivers in the
    * given devclass is allocated and returned in @p *listp.  The number
    * of drivers in the array is returned in @p *countp. The caller should
    * free the array using @c free(p, M_TEMP).
    *
    * @param dc            the devclass to examine
    * @param listp         gives location for array pointer return value
    * @param countp        gives location for number of array elements
    *                      return value
    *
    * @retval 0            success
    * @retval ENOMEM       the array allocation failed
    */
   int
   devclass_get_drivers(devclass_t dc, driver_t ***listp, int *countp)
   {
           driverlink_t dl;
           driver_t **list;
           int count;
   
           count = 0;
           TAILQ_FOREACH(dl, &dc->drivers, link)
                   count++;
           list = kmalloc(count * sizeof(driver_t *), M_TEMP, M_NOWAIT);
           if (list == NULL)
                   return (ENOMEM);
   
           count = 0;
           TAILQ_FOREACH(dl, &dc->drivers, link) {
                   list[count] = dl->driver;
                   count++;
           }
           *listp = list;
           *countp = count;
   
           return (0);
   }
   
   /**
    * @brief Get the number of devices in a devclass
    *
    * @param dc            the devclass to examine
    */
   int
   devclass_get_count(devclass_t dc)
   {
           int count, i;
   
           count = 0;
           for (i = 0; i < dc->maxunit; i++)
                   if (dc->devices[i])
                           count++;
           return (count);
   }
   
   int
   devclass_get_maxunit(devclass_t dc)
   {
           return(dc->maxunit);
   }
   
   void
   devclass_set_parent(devclass_t dc, devclass_t pdc)
   {
           dc->parent = pdc;
   }
   
   devclass_t
   devclass_get_parent(devclass_t dc)
   {
           return(dc->parent);
   }
   
   static int
   devclass_alloc_unit(devclass_t dc, int *unitp)
   {
           int unit = *unitp;
   
           PDEBUG(("unit %d in devclass %s", unit, DEVCLANAME(dc)));
   
           /* If we have been given a wired unit number, check for existing device */
           if (unit != -1) {
                   if (unit >= 0 && unit < dc->maxunit &&
                       dc->devices[unit] != NULL) {
                           if (bootverbose)
                                   kprintf("%s-: %s%d exists, using next available unit number\n",
                                          dc->name, dc->name, unit);
                           /* find the next available slot */
                           while (++unit < dc->maxunit && dc->devices[unit] != NULL)
                                   ;
                   }
           } else {
                   /* Unwired device, find the next available slot for it */
                   unit = 0;
                   while (unit < dc->maxunit && dc->devices[unit] != NULL)
                           unit++;
           }
   
           /*
            * We've selected a unit beyond the length of the table, so let's
            * extend the table to make room for all units up to and including
            * this one.
            */
           if (unit >= dc->maxunit) {
                   device_t *newlist;
                   int newsize;
   
                   newsize = roundup((unit + 1), MINALLOCSIZE / sizeof(device_t));
                   newlist = kmalloc(sizeof(device_t) * newsize, M_BUS,
                                    M_INTWAIT | M_ZERO);
                   if (newlist == NULL)
                           return(ENOMEM);
                   bcopy(dc->devices, newlist, sizeof(device_t) * dc->maxunit);
                   if (dc->devices)
                           kfree(dc->devices, M_BUS);
                   dc->devices = newlist;
                   dc->maxunit = newsize;
           }
           PDEBUG(("now: unit %d in devclass %s", unit, DEVCLANAME(dc)));
   
           *unitp = unit;
           return(0);
   }
   
   static int
   devclass_add_device(devclass_t dc, device_t dev)
   {
           int buflen, error;
   
           PDEBUG(("%s in devclass %s", DEVICENAME(dev), DEVCLANAME(dc)));
   
           buflen = strlen(dc->name) + 5;
           dev->nameunit = kmalloc(buflen, M_BUS, M_INTWAIT | M_ZERO);
           if (!dev->nameunit)
                   return(ENOMEM);
   
           if ((error = devclass_alloc_unit(dc, &dev->unit)) != 0) {
                   kfree(dev->nameunit, M_BUS);
                   dev->nameunit = NULL;
                   return(error);
           }
           dc->devices[dev->unit] = dev;
           dev->devclass = dc;
           ksnprintf(dev->nameunit, buflen, "%s%d", dc->name, dev->unit);
   
           return(0);
   }
   
   static int
   devclass_delete_device(devclass_t dc, device_t dev)
   {
           if (!dc || !dev)
                   return(0);
   
           PDEBUG(("%s in devclass %s", DEVICENAME(dev), DEVCLANAME(dc)));
   
           if (dev->devclass != dc || dc->devices[dev->unit] != dev)
                   panic("devclass_delete_device: inconsistent device class");
           dc->devices[dev->unit] = NULL;
           if (dev->flags & DF_WILDCARD)
                   dev->unit = -1;
           dev->devclass = NULL;
           kfree(dev->nameunit, M_BUS);
           dev->nameunit = NULL;
   
           return(0);
   }
   
  static device_t
  make_device(device_t parent, const char *name, int unit)
  {
          device_t dev;
          devclass_t dc;
  
          PDEBUG(("%s at %s as unit %d", name, DEVICENAME(parent), unit));
  
          if (name != NULL) {
                  dc = devclass_find_internal(name, NULL, TRUE);
                  if (!dc) {
                          kprintf("make_device: can't find device class %s\n", name);
                          return(NULL);
                  }
          } else
                  dc = NULL;
  
          dev = kmalloc(sizeof(struct device), M_BUS, M_INTWAIT | M_ZERO);
          if (!dev)
                  return(0);
  
          dev->parent = parent;
          TAILQ_INIT(&dev->children);
          kobj_init((kobj_t) dev, &null_class);
          dev->driver = NULL;
          dev->devclass = NULL;
          dev->unit = unit;
          dev->nameunit = NULL;
          dev->desc = NULL;
          dev->busy = 0;
          dev->devflags = 0;
          dev->flags = DF_ENABLED;
          dev->order = 0;
          if (unit == -1)
                  dev->flags |= DF_WILDCARD;
          if (name) {
                  dev->flags |= DF_FIXEDCLASS;
                  if (devclass_add_device(dc, dev) != 0) {
                          kobj_delete((kobj_t)dev, M_BUS);
                          return(NULL);
                  }
          }
          dev->ivars = NULL;
          dev->softc = NULL;
  
          dev->state = DS_NOTPRESENT;
  
          TAILQ_INSERT_TAIL(&bus_data_devices, dev, devlink);
          bus_data_generation_update();
  
          return(dev);
  }
  
  static int
  device_print_child(device_t dev, device_t child)
  {
          int retval = 0;
  
          if (device_is_alive(child))
                  retval += BUS_PRINT_CHILD(dev, child);
          else
                  retval += device_printf(child, " not found\n");
  
          return(retval);
  }
  
  device_t
  device_add_child(device_t dev, const char *name, int unit)
  {
          return device_add_child_ordered(dev, 0, name, unit);
  }
  
  device_t
  device_add_child_ordered(device_t dev, int order, const char *name, int unit)
  {
          device_t child;
          device_t place;
  
          PDEBUG(("%s at %s with order %d as unit %d", name, DEVICENAME(dev),
                  order, unit));
  
          child = make_device(dev, name, unit);
          if (child == NULL)
                  return child;
          child->order = order;
  
          TAILQ_FOREACH(place, &dev->children, link)
                  if (place->order > order)
                          break;
  
          if (place) {
                  /*
                   * The device 'place' is the first device whose order is
                   * greater than the new child.
                   */
                  TAILQ_INSERT_BEFORE(place, child, link);
          } else {
                  /*
                   * The new child's order is greater or equal to the order of
                   * any existing device. Add the child to the tail of the list.
                   */
                  TAILQ_INSERT_TAIL(&dev->children, child, link);
          }
  
          bus_data_generation_update();
          return(child);
  }
  
  int
  device_delete_child(device_t dev, device_t child)
  {
          int error;
          device_t grandchild;
  
          PDEBUG(("%s from %s", DEVICENAME(child), DEVICENAME(dev)));
  
          /* remove children first */
          while ( (grandchild = TAILQ_FIRST(&child->children)) ) {
                  error = device_delete_child(child, grandchild);
                  if (error)
                          return(error);
          }
  
          if ((error = device_detach(child)) != 0)
                  return(error);
          if (child->devclass)
                  devclass_delete_device(child->devclass, child);
          TAILQ_REMOVE(&dev->children, child, link);
          TAILQ_REMOVE(&bus_data_devices, child, devlink);
          device_set_desc(child, NULL);
          kobj_delete((kobj_t)child, M_BUS);
  
          bus_data_generation_update();
          return(0);
  }
  
  /**
   * @brief Delete all children devices of the given device, if any.
   *
   * This function deletes all children devices of the given device, if
   * any, using the device_delete_child() function for each device it
   * finds. If a child device cannot be deleted, this function will
   * return an error code.
   * 
   * @param dev           the parent device
   *
   * @retval 0            success
   * @retval non-zero     a device would not detach
   */
  int
  device_delete_children(device_t dev)
  {
          device_t child;
          int error;
  
          PDEBUG(("Deleting all children of %s", DEVICENAME(dev)));
  
          error = 0;
  
          while ((child = TAILQ_FIRST(&dev->children)) != NULL) {
                  error = device_delete_child(dev, child);
                  if (error) {
                          PDEBUG(("Failed deleting %s", DEVICENAME(child)));
                          break;
                  }
          }
          return (error);
  }
  
  /**
   * @brief Find a device given a unit number
   *
   * This is similar to devclass_get_devices() but only searches for
   * devices which have @p dev as a parent.
   *
   * @param dev           the parent device to search
   * @param unit          the unit number to search for.  If the unit is -1,
   *                      return the first child of @p dev which has name
   *                      @p classname (that is, the one with the lowest unit.)
   *
   * @returns             the device with the given unit number or @c
   *                      NULL if there is no such device
   */
  device_t
  device_find_child(device_t dev, const char *classname, int unit)
  {
          devclass_t dc;
          device_t child;
  
          dc = devclass_find(classname);
          if (!dc)
                  return(NULL);
  
          if (unit != -1) {
                  child = devclass_get_device(dc, unit);
                  if (child && child->parent == dev)
                          return (child);
          } else {
                  for (unit = 0; unit < devclass_get_maxunit(dc); unit++) {
                          child = devclass_get_device(dc, unit);
                          if (child && child->parent == dev)
                                  return (child);
                  }
          }
          return(NULL);
  }
  
  static driverlink_t
  first_matching_driver(devclass_t dc, device_t dev)
  {
          if (dev->devclass)
                  return(devclass_find_driver_internal(dc, dev->devclass->name));
          else
                  return(TAILQ_FIRST(&dc->drivers));
  }
  
  static driverlink_t
  next_matching_driver(devclass_t dc, device_t dev, driverlink_t last)
  {
          if (dev->devclass) {
                  driverlink_t dl;
                  for (dl = TAILQ_NEXT(last, link); dl; dl = TAILQ_NEXT(dl, link))
                          if (!strcmp(dev->devclass->name, dl->driver->name))
                                  return(dl);
                  return(NULL);
          } else
                  return(TAILQ_NEXT(last, link));
  }
  
  int
  device_probe_child(device_t dev, device_t child)
  {
          devclass_t dc;
          driverlink_t best = NULL;
          driverlink_t dl;
          int result, pri = 0;
          int hasclass = (child->devclass != NULL);
  
          dc = dev->devclass;
          if (!dc)
                  panic("device_probe_child: parent device has no devclass");
  
          if (child->state == DS_ALIVE)
                  return(0);
  
          for (; dc; dc = dc->parent) {
                  for (dl = first_matching_driver(dc, child); dl;
                       dl = next_matching_driver(dc, child, dl)) {
                          PDEBUG(("Trying %s", DRIVERNAME(dl->driver)));
                          device_set_driver(child, dl->driver);
                          if (!hasclass)
                                  device_set_devclass(child, dl->driver->name);
                          result = DEVICE_PROBE(child);
                          if (!hasclass)
                                  device_set_devclass(child, 0);
  
                          /*
                           * If the driver returns SUCCESS, there can be
                           * no higher match for this device.
                           */
                          if (result == 0) {
                                  best = dl;
                                  pri = 0;
                                  break;
                          }
  
                          /*
                           * The driver returned an error so it
                           * certainly doesn't match.
                           */
                          if (result > 0) {
                                  device_set_driver(child, 0);
                                  continue;
                          }
  
                          /*
                           * A priority lower than SUCCESS, remember the
                           * best matching driver. Initialise the value
                           * of pri for the first match.
                           */
                          if (best == NULL || result > pri) {
                                  best = dl;
                                  pri = result;
                                  continue;
                          }
                  }
                  /*
                   * If we have unambiguous match in this devclass,
                   * don't look in the parent.
                   */
                  if (best && pri == 0)
                          break;
          }
  
          /*
           * If we found a driver, change state and initialise the devclass.
           */
          if (best) {
                  if (!child->devclass)
                          device_set_devclass(child, best->driver->name);
                  device_set_driver(child, best->driver);
                  if (pri < 0) {
                          /*
                           * A bit bogus. Call the probe method again to make
                           * sure that we have the right description.
                           */
                          DEVICE_PROBE(child);
                  }
  
                  bus_data_generation_update();
                  child->state = DS_ALIVE;
                  return(0);
          }
  
          return(ENXIO);
  }
  
  device_t
  device_get_parent(device_t dev)
  {
          return dev->parent;
  }
  
  int
  device_get_children(device_t dev, device_t **devlistp, int *devcountp)
  {
          int count;
          device_t child;
          device_t *list;
      
          count = 0;
          TAILQ_FOREACH(child, &dev->children, link)
                  count++;
  
          list = kmalloc(count * sizeof(device_t), M_TEMP, M_INTWAIT | M_ZERO);
  
          count = 0;
          TAILQ_FOREACH(child, &dev->children, link) {
                  list[count] = child;
                  count++;
          }
  
          *devlistp = list;
          *devcountp = count;
  
          return(0);
  }
  
  driver_t *
  device_get_driver(device_t dev)
  {
          return(dev->driver);
  }
  
  devclass_t
  device_get_devclass(device_t dev)
  {
          return(dev->devclass);
  }
  
  const char *
  device_get_name(device_t dev)
  {
          if (dev->devclass)
                  return devclass_get_name(dev->devclass);
          return(NULL);
  }
  
  const char *
  device_get_nameunit(device_t dev)
  {
          return(dev->nameunit);
  }
  
  int
  device_get_unit(device_t dev)
  {
          return(dev->unit);
  }
  
  const char *
  device_get_desc(device_t dev)
  {
          return(dev->desc);
  }
  
  uint32_t
  device_get_flags(device_t dev)
  {
          return(dev->devflags);
  }
  
  int
  device_print_prettyname(device_t dev)
  {
          const char *name = device_get_name(dev);
  
          if (name == NULL)
                  return kprintf("unknown: ");
          else
                  return kprintf("%s%d: ", name, device_get_unit(dev));
  }
  
  int
  device_printf(device_t dev, const char * fmt, ...)
  {
          __va_list ap;
          int retval;
  
          retval = device_print_prettyname(dev);
          __va_start(ap, fmt);
          retval += kvprintf(fmt, ap);
          __va_end(ap);
          return retval;
  }
  
  static void
  device_set_desc_internal(device_t dev, const char* desc, int copy)
  {
          if (dev->desc && (dev->flags & DF_DESCMALLOCED)) {
                  kfree(dev->desc, M_BUS);
                  dev->flags &= ~DF_DESCMALLOCED;
                  dev->desc = NULL;
          }
  
          if (copy && desc) {
                  dev->desc = kmalloc(strlen(desc) + 1, M_BUS, M_INTWAIT);
                  if (dev->desc) {
                          strcpy(dev->desc, desc);
                          dev->flags |= DF_DESCMALLOCED;
                  }
          } else {
                  /* Avoid a -Wcast-qual warning */
                  dev->desc = (char *)(uintptr_t) desc;
          }
  
          bus_data_generation_update();
  }
  
  void
  device_set_desc(device_t dev, const char* desc)
  {
          device_set_desc_internal(dev, desc, FALSE);
  }
  
  void
  device_set_desc_copy(device_t dev, const char* desc)
  {
          device_set_desc_internal(dev, desc, TRUE);
  }
  
  void
  device_set_flags(device_t dev, uint32_t flags)
  {
          dev->devflags = flags;
  }
  
  void *
  device_get_softc(device_t dev)
  {
          return dev->softc;
  }
  
  void
  device_set_softc(device_t dev, void *softc)
  {
          if (dev->softc && !(dev->flags & DF_EXTERNALSOFTC))
                  kfree(dev->softc, M_BUS);
          dev->softc = softc;
          if (dev->softc)
                  dev->flags |= DF_EXTERNALSOFTC;
          else
                  dev->flags &= ~DF_EXTERNALSOFTC;
  }
  
  void
  device_set_async_attach(device_t dev, int enable)
  {
          if (enable)
                  dev->flags |= DF_ASYNCPROBE;
          else
                  dev->flags &= ~DF_ASYNCPROBE;
  }
  
  void *
  device_get_ivars(device_t dev)
  {
          return dev->ivars;
  }
  
  void
  device_set_ivars(device_t dev, void * ivars)
  {
          if (!dev)
                  return;
  
          dev->ivars = ivars;
  }
  
  device_state_t
  device_get_state(device_t dev)
  {
          return(dev->state);
  }
  
  void
  device_enable(device_t dev)
  {
          dev->flags |= DF_ENABLED;
  }
  
  void
  device_disable(device_t dev)
  {
          dev->flags &= ~DF_ENABLED;
  }
  
  /*
   * YYY cannot block
   */
  void
  device_busy(device_t dev)
  {
          if (dev->state < DS_ATTACHED)
                  panic("device_busy: called for unattached device");
          if (dev->busy == 0 && dev->parent)
                  device_busy(dev->parent);
          dev->busy++;
          dev->state = DS_BUSY;
  }
  
  /*
   * YYY cannot block
   */
  void
  device_unbusy(device_t dev)
  {
          if (dev->state != DS_BUSY)
                  panic("device_unbusy: called for non-busy device");
          dev->busy--;
          if (dev->busy == 0) {
                  if (dev->parent)
                          device_unbusy(dev->parent);
                  dev->state = DS_ATTACHED;
          }
  }
  
  void
  device_quiet(device_t dev)
  {
          dev->flags |= DF_QUIET;
  }
  
  void
  device_verbose(device_t dev)
  {
          dev->flags &= ~DF_QUIET;
  }
  
  int
  device_is_quiet(device_t dev)
  {
          return((dev->flags & DF_QUIET) != 0);
  }
  
  int
  device_is_enabled(device_t dev)
  {
          return((dev->flags & DF_ENABLED) != 0);
  }
  
  int
  device_is_alive(device_t dev)
  {
          return(dev->state >= DS_ALIVE);
  }
  
  int
  device_is_attached(device_t dev)
  {
          return(dev->state >= DS_ATTACHED);
  }
  
  int
  device_set_devclass(device_t dev, const char *classname)
  {
          devclass_t dc;
          int error;
  
          if (!classname) {
                  if (dev->devclass)
                          devclass_delete_device(dev->devclass, dev);
                  return(0);
          }
  
          if (dev->devclass) {
                  kprintf("device_set_devclass: device class already set\n");
                  return(EINVAL);
          }
  
          dc = devclass_find_internal(classname, NULL, TRUE);
          if (!dc)
                  return(ENOMEM);
  
          error = devclass_add_device(dc, dev);
  
          bus_data_generation_update();
          return(error);
  }
  
  int
  device_set_driver(device_t dev, driver_t *driver)
  {
          if (dev->state >= DS_ATTACHED)
                  return(EBUSY);
  
          if (dev->driver == driver)
                  return(0);
  
          if (dev->softc && !(dev->flags & DF_EXTERNALSOFTC)) {
                  kfree(dev->softc, M_BUS);
                  dev->softc = NULL;
          }
          kobj_delete((kobj_t) dev, 0);
          dev->driver = driver;
          if (driver) {
                  kobj_init((kobj_t) dev, (kobj_class_t) driver);
                  if (!(dev->flags & DF_EXTERNALSOFTC))
                          dev->softc = kmalloc(driver->size, M_BUS,
                                              M_INTWAIT | M_ZERO);
          } else {
                  kobj_init((kobj_t) dev, &null_class);
          }
  
          bus_data_generation_update();
          return(0);
  }
  
  int
  device_probe_and_attach(device_t dev)
  {
          device_t bus = dev->parent;
          int error = 0;
  
          if (dev->state >= DS_ALIVE)
                  return(0);
  
          if ((dev->flags & DF_ENABLED) == 0) {
                  if (bootverbose) {
                          device_print_prettyname(dev);
                          kprintf("not probed (disabled)\n");
                  }
                  return(0);
          }
  
          error = device_probe_child(bus, dev);
          if (error) {
                  if (!(dev->flags & DF_DONENOMATCH)) {
                          BUS_PROBE_NOMATCH(bus, dev);
                          devnomatch(dev);
                          dev->flags |= DF_DONENOMATCH;
                  }
                  return(error);
          }
  
          /*
           * Output the exact device chain prior to the attach in case the  
           * system locks up during attach, and generate the full info after
           * the attach so correct irq and other information is displayed.
           */
          if (bootverbose && !device_is_quiet(dev)) {
                  device_t tmp;
  
                  kprintf("%s", device_get_nameunit(dev));
                  for (tmp = dev->parent; tmp; tmp = tmp->parent)
                          kprintf(".%s", device_get_nameunit(tmp));
                  kprintf("\n");
          }
          if (!device_is_quiet(dev))
                  device_print_child(bus, dev);
          if ((dev->flags & DF_ASYNCPROBE) && do_async_attach) {
                  kprintf("%s: probing asynchronously\n",
                          device_get_nameunit(dev));
                  dev->state = DS_INPROGRESS;
                  device_attach_async(dev);
                  error = 0;
          } else {
                  error = device_doattach(dev);
          }
          return(error);
  }
  
  /*
   * Device is known to be alive, do the attach asynchronously.
   * However, serialize the attaches with the mp lock.
   */
  static void
  device_attach_async(device_t dev)
  {
          thread_t td;
  
          atomic_add_int(&numasyncthreads, 1);
          lwkt_create(device_attach_thread, dev, &td, NULL,
                      0, 0, "%s", (dev->desc ? dev->desc : "devattach"));
  }
  
  static void
  device_attach_thread(void *arg)
  {
          device_t dev = arg;
  
          get_mplock();   /* XXX replace with devattach_token later */
          (void)device_doattach(dev);
          atomic_subtract_int(&numasyncthreads, 1);
          wakeup(&numasyncthreads);
          rel_mplock();   /* XXX replace with devattach_token later */
  }
  
  /*
   * Device is known to be alive, do the attach (synchronous or asynchronous)
   */
  static int
  device_doattach(device_t dev)
  {
          device_t bus = dev->parent;
          int hasclass = (dev->devclass != NULL);
          int error;
  
          error = DEVICE_ATTACH(dev);
          if (error == 0) {
                  dev->state = DS_ATTACHED;
                  if (bootverbose && !device_is_quiet(dev))
                          device_print_child(bus, dev);
                  devadded(dev);
          } else {
                  kprintf("device_probe_and_attach: %s%d attach returned %d\n",
                         dev->driver->name, dev->unit, error);
                  /* Unset the class that was set in device_probe_child */
                  if (!hasclass)
                          device_set_devclass(dev, 0);
                  device_set_driver(dev, NULL);
                  dev->state = DS_NOTPRESENT;
          }
          return(error);
  }
  
  int
  device_detach(device_t dev)
  {
          int error;
  
          PDEBUG(("%s", DEVICENAME(dev)));
          if (dev->state == DS_BUSY)
                  return(EBUSY);
          if (dev->state != DS_ATTACHED)
                  return(0);
  
          if ((error = DEVICE_DETACH(dev)) != 0)
                  return(error);
          devremoved(dev);
          device_printf(dev, "detached\n");
          if (dev->parent)
                  BUS_CHILD_DETACHED(dev->parent, dev);
  
          if (!(dev->flags & DF_FIXEDCLASS))
                  devclass_delete_device(dev->devclass, dev);
  
          dev->state = DS_NOTPRESENT;
          device_set_driver(dev, NULL);
  
          return(0);
  }
  
  int
  device_shutdown(device_t dev)
  {
          if (dev->state < DS_ATTACHED)
                  return 0;
          PDEBUG(("%s", DEVICENAME(dev)));
          return DEVICE_SHUTDOWN(dev);
  }
  
  int
  device_set_unit(device_t dev, int unit)
  {
          devclass_t dc;
          int err;
  
          dc = device_get_devclass(dev);
          if (unit < dc->maxunit && dc->devices[unit])
                  return(EBUSY);
          err = devclass_delete_device(dc, dev);
          if (err)
                  return(err);
          dev->unit = unit;
          err = devclass_add_device(dc, dev);
          if (err)
                  return(err);
  
          bus_data_generation_update();
          return(0);
  }
  
  /*======================================*/
  /*
   * Access functions for device resources.
   */
  
  /* Supplied by config(8) in ioconf.c */
  extern struct config_device config_devtab[];
  extern int devtab_count;
  
  /* Runtime version */
  struct config_device *devtab = config_devtab;
  
  static int
  resource_new_name(const char *name, int unit)
  {
          struct config_device *new;
  
          new = kmalloc((devtab_count + 1) * sizeof(*new), M_TEMP,
                       M_INTWAIT | M_ZERO);
          if (devtab && devtab_count > 0)
                  bcopy(devtab, new, devtab_count * sizeof(*new));
          new[devtab_count].name = kmalloc(strlen(name) + 1, M_TEMP, M_INTWAIT);
          if (new[devtab_count].name == NULL) {
                  kfree(new, M_TEMP);
                  return(-1);
          }
          strcpy(new[devtab_count].name, name);
          new[devtab_count].unit = unit;
          new[devtab_count].resource_count = 0;
          new[devtab_count].resources = NULL;
          if (devtab && devtab != config_devtab)
                  kfree(devtab, M_TEMP);
          devtab = new;
          return devtab_count++;
  }
  
  static int
  resource_new_resname(int j, const char *resname, resource_type type)
  {
          struct config_resource *new;
          int i;
  
          i = devtab[j].resource_count;
          new = kmalloc((i + 1) * sizeof(*new), M_TEMP, M_INTWAIT | M_ZERO);
          if (devtab[j].resources && i > 0)
                  bcopy(devtab[j].resources, new, i * sizeof(*new));
          new[i].name = kmalloc(strlen(resname) + 1, M_TEMP, M_INTWAIT);
          if (new[i].name == NULL) {
                  kfree(new, M_TEMP);
                  return(-1);
          }
          strcpy(new[i].name, resname);
          new[i].type = type;
          if (devtab[j].resources)
                  kfree(devtab[j].resources, M_TEMP);
          devtab[j].resources = new;
          devtab[j].resource_count = i + 1;
          return(i);
  }
  
  static int
  resource_match_string(int i, const char *resname, const char *value)
  {
          int j;
          struct config_resource *res;
  
          for (j = 0, res = devtab[i].resources;
               j < devtab[i].resource_count; j++, res++)
                  if (!strcmp(res->name, resname)
                      && res->type == RES_STRING
                      && !strcmp(res->u.stringval, value))
                          return(j);
          return(-1);
  }
  
  static int
  resource_find(const char *name, int unit, const char *resname, 
                struct config_resource **result)
  {
          int i, j;
          struct config_resource *res;
  
          /*
           * First check specific instances, then generic.
           */
          for (i = 0; i < devtab_count; i++) {
                  if (devtab[i].unit < 0)
                          continue;
                  if (!strcmp(devtab[i].name, name) && devtab[i].unit == unit) {
                          res = devtab[i].resources;
                          for (j = 0; j < devtab[i].resource_count; j++, res++)
                                  if (!strcmp(res->name, resname)) {
                                          *result = res;
                                          return(0);
                                  }
                  }
          }
          for (i = 0; i < devtab_count; i++) {
                  if (devtab[i].unit >= 0)
                          continue;
                  /* XXX should this `&& devtab[i].unit == unit' be here? */
                  /* XXX if so, then the generic match does nothing */
                  if (!strcmp(devtab[i].name, name) && devtab[i].unit == unit) {
                          res = devtab[i].resources;
                          for (j = 0; j < devtab[i].resource_count; j++, res++)
                                  if (!strcmp(res->name, resname)) {
                                          *result = res;
                                          return(0);
                                  }
                  }
          }
          return(ENOENT);
  }
  
  static int
  resource_kenv(const char *name, int unit, const char *resname, long *result)
  {
          const char *env;
          char buf[64];
  
          ksnprintf(buf, sizeof(buf), "%s%d.%s", name, unit, resname);
          if ((env = kgetenv(buf)) != NULL) {
                  *result = strtol(env, NULL, 0);
                  return(0);
          }
          return (ENOENT);
  }
  
  int
  resource_int_value(const char *name, int unit, const char *resname, int *result)
  {
          struct config_resource *res;
          long kvalue = 0;
          int error;
  
          if (resource_kenv(name, unit, resname, &kvalue) == 0) {
                  *result = (int)kvalue;
                  return 0;
          }
          if ((error = resource_find(name, unit, resname, &res)) != 0)
                  return(error);
          if (res->type != RES_INT)
                  return(EFTYPE);
          *result = res->u.intval;
          return(0);
  }
  
  int
  resource_long_value(const char *name, int unit, const char *resname,
                      long *result)
  {
          struct config_resource *res;
          long kvalue;
          int error;
  
          if (resource_kenv(name, unit, resname, &kvalue) == 0) {
                  *result = kvalue;
                  return 0;
          }
          if ((error = resource_find(name, unit, resname, &res)) != 0)
                  return(error);
          if (res->type != RES_LONG)
                  return(EFTYPE);
          *result = res->u.longval;
          return(0);
  }
  
  int
  resource_string_value(const char *name, int unit, const char *resname,
                        char **result)
  {
          int error;
          struct config_resource *res;
  
          if ((error = resource_find(name, unit, resname, &res)) != 0)
                  return(error);
          if (res->type != RES_STRING)
                  return(EFTYPE);
          *result = res->u.stringval;
          return(0);
  }
  
  int
  resource_query_string(int i, const char *resname, const char *value)
  {
          if (i < 0)
                  i = 0;
          else
                  i = i + 1;
          for (; i < devtab_count; i++)
                  if (resource_match_string(i, resname, value) >= 0)
                          return(i);
          return(-1);
  }
  
  int
  resource_locate(int i, const char *resname)
  {
          if (i < 0)
                  i = 0;
          else
                  i = i + 1;
          for (; i < devtab_count; i++)
                  if (!strcmp(devtab[i].name, resname))
                          return(i);
          return(-1);
  }
  
  int
  resource_count(void)
  {
          return(devtab_count);
  }
  
  char *
  resource_query_name(int i)
  {
          return(devtab[i].name);
  }
  
  int
  resource_query_unit(int i)
  {
          return(devtab[i].unit);
  }
  
  static int
  resource_create(const char *name, int unit, const char *resname,
                  resource_type type, struct config_resource **result)
  {
          int i, j;
          struct config_resource *res = NULL;
  
          for (i = 0; i < devtab_count; i++)
                  if (!strcmp(devtab[i].name, name) && devtab[i].unit == unit) {
                          res = devtab[i].resources;
                          break;
                  }
          if (res == NULL) {
                  i = resource_new_name(name, unit);
                  if (i < 0)
                          return(ENOMEM);
                  res = devtab[i].resources;
          }
          for (j = 0; j < devtab[i].resource_count; j++, res++)
                  if (!strcmp(res->name, resname)) {
                          *result = res;
                          return(0);
                  }
          j = resource_new_resname(i, resname, type);
          if (j < 0)
                  return(ENOMEM);
          res = &devtab[i].resources[j];
          *result = res;
          return(0);
  }
  
  int
  resource_set_int(const char *name, int unit, const char *resname, int value)
  {
          int error;
          struct config_resource *res;
  
          error = resource_create(name, unit, resname, RES_INT, &res);
          if (error)
                  return(error);
          if (res->type != RES_INT)
                  return(EFTYPE);
          res->u.intval = value;
          return(0);
  }
  
  int
  resource_set_long(const char *name, int unit, const char *resname, long value)
  {
          int error;
          struct config_resource *res;
  
          error = resource_create(name, unit, resname, RES_LONG, &res);
          if (error)
                  return(error);
          if (res->type != RES_LONG)
                  return(EFTYPE);
          res->u.longval = value;
          return(0);
  }
  
  int
  resource_set_string(const char *name, int unit, const char *resname,
                      const char *value)
  {
          int error;
          struct config_resource *res;
  
          error = resource_create(name, unit, resname, RES_STRING, &res);
          if (error)
                  return(error);
          if (res->type != RES_STRING)
                  return(EFTYPE);
          if (res->u.stringval)
                  kfree(res->u.stringval, M_TEMP);
          res->u.stringval = kmalloc(strlen(value) + 1, M_TEMP, M_INTWAIT);
          if (res->u.stringval == NULL)
                  return(ENOMEM);
          strcpy(res->u.stringval, value);
          return(0);
  }
  
  static void
  resource_cfgload(void *dummy __unused)
  {
          struct config_resource *res, *cfgres;
          int i, j;
          int error;
          char *name, *resname;
          int unit;
          resource_type type;
          char *stringval;
          int config_devtab_count;
  
          config_devtab_count = devtab_count;
          devtab = NULL;
          devtab_count = 0;
  
          for (i = 0; i < config_devtab_count; i++) {
                  name = config_devtab[i].name;
                  unit = config_devtab[i].unit;
  
                  for (j = 0; j < config_devtab[i].resource_count; j++) {
                          cfgres = config_devtab[i].resources;
                          resname = cfgres[j].name;
                          type = cfgres[j].type;
                          error = resource_create(name, unit, resname, type,
                                                  &res);
                          if (error) {
                                  kprintf("create resource %s%d: error %d\n",
                                          name, unit, error);
                                  continue;
                          }
                          if (res->type != type) {
                                  kprintf("type mismatch %s%d: %d != %d\n",
                                          name, unit, res->type, type);
                                  continue;
                          }
                          switch (type) {
                          case RES_INT:
                                  res->u.intval = cfgres[j].u.intval;
                                  break;
                          case RES_LONG:
                                  res->u.longval = cfgres[j].u.longval;
                                  break;
                          case RES_STRING:
                                  if (res->u.stringval)
                                          kfree(res->u.stringval, M_TEMP);
                                  stringval = cfgres[j].u.stringval;
                                  res->u.stringval = kmalloc(strlen(stringval) + 1,
                                                            M_TEMP, M_INTWAIT);
                                  if (res->u.stringval == NULL)
                                          break;
                                  strcpy(res->u.stringval, stringval);
                                  break;
                          default:
                                  panic("unknown resource type %d", type);
                          }
                  }
          }
  }
  SYSINIT(cfgload, SI_BOOT1_POST, SI_ORDER_ANY + 50, resource_cfgload, 0)
  
  
  /*======================================*/
  /*
   * Some useful method implementations to make life easier for bus drivers.
   */
  
  void
  resource_list_init(struct resource_list *rl)
  {
          SLIST_INIT(rl);
  }
  
  void
  resource_list_free(struct resource_list *rl)
  {
          struct resource_list_entry *rle;
  
          while ((rle = SLIST_FIRST(rl)) != NULL) {
                  if (rle->res)
                          panic("resource_list_free: resource entry is busy");
                  SLIST_REMOVE_HEAD(rl, link);
                  kfree(rle, M_BUS);
          }
  }
  
  void
  resource_list_add(struct resource_list *rl, int type, int rid,
      u_long start, u_long end, u_long count, int cpuid)
  {
          struct resource_list_entry *rle;
  
          rle = resource_list_find(rl, type, rid);
          if (rle == NULL) {
                  rle = kmalloc(sizeof(struct resource_list_entry), M_BUS,
                               M_INTWAIT);
                  SLIST_INSERT_HEAD(rl, rle, link);
                  rle->type = type;
                  rle->rid = rid;
                  rle->res = NULL;
                  rle->cpuid = -1;
          }
  
          if (rle->res)
                  panic("resource_list_add: resource entry is busy");
  
          rle->start = start;
          rle->end = end;
          rle->count = count;
  
          if (cpuid != -1) {
                  if (rle->cpuid != -1 && rle->cpuid != cpuid) {
                          panic("resource_list_add: moving from cpu%d -> cpu%d",
                              rle->cpuid, cpuid);
                  }
                  rle->cpuid = cpuid;
          }
  }
  
  struct resource_list_entry*
  resource_list_find(struct resource_list *rl,
                     int type, int rid)
  {
          struct resource_list_entry *rle;
  
          SLIST_FOREACH(rle, rl, link)
                  if (rle->type == type && rle->rid == rid)
                          return(rle);
          return(NULL);
  }
  
  void
  resource_list_delete(struct resource_list *rl,
                       int type, int rid)
  {
          struct resource_list_entry *rle = resource_list_find(rl, type, rid);
  
          if (rle) {
                  if (rle->res != NULL)
                          panic("resource_list_delete: resource has not been released");
                  SLIST_REMOVE(rl, rle, resource_list_entry, link);
                  kfree(rle, M_BUS);
          }
  }
  
  struct resource *
  resource_list_alloc(struct resource_list *rl,
                      device_t bus, device_t child,
                      int type, int *rid,
                      u_long start, u_long end,
                      u_long count, u_int flags, int cpuid)
  {
          struct resource_list_entry *rle = NULL;
          int passthrough = (device_get_parent(child) != bus);
          int isdefault = (start == 0UL && end == ~0UL);
  
          if (passthrough) {
                  return(BUS_ALLOC_RESOURCE(device_get_parent(bus), child,
                                            type, rid,
                                            start, end, count, flags, cpuid));
          }
  
          rle = resource_list_find(rl, type, *rid);
  
          if (!rle)
                  return(0);              /* no resource of that type/rid */
  
          if (rle->res)
                  panic("resource_list_alloc: resource entry is busy");
  
          if (isdefault) {
                  start = rle->start;
                  count = max(count, rle->count);
                  end = max(rle->end, start + count - 1);
          }
          cpuid = rle->cpuid;
  
          rle->res = BUS_ALLOC_RESOURCE(device_get_parent(bus), child,
                                        type, rid, start, end, count,
                                        flags, cpuid);
  
          /*
           * Record the new range.
           */
          if (rle->res) {
                  rle->start = rman_get_start(rle->res);
                  rle->end = rman_get_end(rle->res);
                  rle->count = count;
          }
  
          return(rle->res);
  }
  
  int
  resource_list_release(struct resource_list *rl,
                        device_t bus, device_t child,
                        int type, int rid, struct resource *res)
  {
          struct resource_list_entry *rle = NULL;
          int passthrough = (device_get_parent(child) != bus);
          int error;
  
          if (passthrough) {
                  return(BUS_RELEASE_RESOURCE(device_get_parent(bus), child,
                                              type, rid, res));
          }
  
          rle = resource_list_find(rl, type, rid);
  
          if (!rle)
                  panic("resource_list_release: can't find resource");
          if (!rle->res)
                  panic("resource_list_release: resource entry is not busy");
  
          error = BUS_RELEASE_RESOURCE(device_get_parent(bus), child,
                                       type, rid, res);
          if (error)
                  return(error);
  
          rle->res = NULL;
          return(0);
  }
  
  int
  resource_list_print_type(struct resource_list *rl, const char *name, int type,
                           const char *format)
  {
          struct resource_list_entry *rle;
          int printed, retval;
  
          printed = 0;
          retval = 0;
          /* Yes, this is kinda cheating */
          SLIST_FOREACH(rle, rl, link) {
                  if (rle->type == type) {
                          if (printed == 0)
                                  retval += kprintf(" %s ", name);
                          else
                                  retval += kprintf(",");
                          printed++;
                          retval += kprintf(format, rle->start);
                          if (rle->count > 1) {
                                  retval += kprintf("-");
                                  retval += kprintf(format, rle->start +
                                                   rle->count - 1);
                          }
                  }
          }
          return(retval);
  }
  
  /*
   * Generic driver/device identify functions.  These will install a device
   * rendezvous point under the parent using the same name as the driver
   * name, which will at a later time be probed and attached.
   *
   * These functions are used when the parent does not 'scan' its bus for
   * matching devices, or for the particular devices using these functions,
   * or when the device is a pseudo or synthesized device (such as can be
   * found under firewire and ppbus).
   */
  int
  bus_generic_identify(driver_t *driver, device_t parent)
  {
          if (parent->state == DS_ATTACHED)
                  return (0);
          BUS_ADD_CHILD(parent, parent, 0, driver->name, -1);
          return (0);
  }
  
  int
  bus_generic_identify_sameunit(driver_t *driver, device_t parent)
  {
          if (parent->state == DS_ATTACHED)
                  return (0);
          BUS_ADD_CHILD(parent, parent, 0, driver->name, device_get_unit(parent));
          return (0);
  }
  
  /*
   * Call DEVICE_IDENTIFY for each driver.
   */
  int
  bus_generic_probe(device_t dev)
  {
          devclass_t dc = dev->devclass;
          driverlink_t dl;
  
          TAILQ_FOREACH(dl, &dc->drivers, link) {
                  DEVICE_IDENTIFY(dl->driver, dev);
          }
  
          return(0);
  }
  
  /*
   * This is an aweful hack due to the isa bus and autoconf code not
   * probing the ISA devices until after everything else has configured.
   * The ISA bus did a dummy attach long ago so we have to set it back
   * to an earlier state so the probe thinks its the initial probe and
   * not a bus rescan.
   *
   * XXX remove by properly defering the ISA bus scan.
   */
  int
  bus_generic_probe_hack(device_t dev)
  {
          if (dev->state == DS_ATTACHED) {
                  dev->state = DS_ALIVE;
                  bus_generic_probe(dev);
                  dev->state = DS_ATTACHED;
          }
          return (0);
  }
  
  int
  bus_generic_attach(device_t dev)
  {
          device_t child;
  
          TAILQ_FOREACH(child, &dev->children, link) {
                  device_probe_and_attach(child);
          }
  
          return(0);
  }
  
  int
  bus_generic_detach(device_t dev)
  {
          device_t child;
          int error;
  
          if (dev->state != DS_ATTACHED)
                  return(EBUSY);
  
          TAILQ_FOREACH(child, &dev->children, link)
                  if ((error = device_detach(child)) != 0)
                          return(error);
  
          return 0;
  }
  
  int
  bus_generic_shutdown(device_t dev)
  {
          device_t child;
  
          TAILQ_FOREACH(child, &dev->children, link)
                  device_shutdown(child);
  
          return(0);
  }
  
  int
  bus_generic_suspend(device_t dev)
  {
          int error;
          device_t child, child2;
  
          TAILQ_FOREACH(child, &dev->children, link) {
                  error = DEVICE_SUSPEND(child);
                  if (error) {
                          for (child2 = TAILQ_FIRST(&dev->children);
                               child2 && child2 != child; 
                               child2 = TAILQ_NEXT(child2, link))
                                  DEVICE_RESUME(child2);
                          return(error);
                  }
          }
          return(0);
  }
  
  int
  bus_generic_resume(device_t dev)
  {
          device_t child;
  
          TAILQ_FOREACH(child, &dev->children, link)
                  DEVICE_RESUME(child);
                  /* if resume fails, there's nothing we can usefully do... */
  
          return(0);
  }
  
  int
  bus_print_child_header(device_t dev, device_t child)
  {
          int retval = 0;
  
          if (device_get_desc(child))
                  retval += device_printf(child, "<%s>", device_get_desc(child));
          else
                  retval += kprintf("%s", device_get_nameunit(child));
          if (bootverbose) {
                  if (child->state != DS_ATTACHED)
                          kprintf(" [tentative]");
                  else
                          kprintf(" [attached!]");
          }
          return(retval);
  }
  
  int
  bus_print_child_footer(device_t dev, device_t child)
  {
          return(kprintf(" on %s\n", device_get_nameunit(dev)));
  }
  
  device_t
  bus_generic_add_child(device_t dev, device_t child, int order,
                        const char *name, int unit)
  {
          if (dev->parent)
                  dev = BUS_ADD_CHILD(dev->parent, child, order, name, unit);
          else
                  dev = device_add_child_ordered(child, order, name, unit);
          return(dev);
                  
  }
  
  int
  bus_generic_print_child(device_t dev, device_t child)
  {
          int retval = 0;
  
          retval += bus_print_child_header(dev, child);
          retval += bus_print_child_footer(dev, child);
  
          return(retval);
  }
  
  int
  bus_generic_read_ivar(device_t dev, device_t child, int index, 
                        uintptr_t * result)
  {
          int error;
  
          if (dev->parent)
                  error = BUS_READ_IVAR(dev->parent, child, index, result);
          else
                  error = ENOENT;
          return (error);
  }
  
  int
  bus_generic_write_ivar(device_t dev, device_t child, int index, 
                         uintptr_t value)
  {
          int error;
  
          if (dev->parent)
                  error = BUS_WRITE_IVAR(dev->parent, child, index, value);
          else
                  error = ENOENT;
          return (error);
  }
  
  /*
   * Resource list are used for iterations, do not recurse.
   */
  struct resource_list *
  bus_generic_get_resource_list(device_t dev, device_t child)
  {
          return (NULL);
  }
  
  void
  bus_generic_driver_added(device_t dev, driver_t *driver)
  {
          device_t child;
  
          DEVICE_IDENTIFY(driver, dev);
          TAILQ_FOREACH(child, &dev->children, link) {
                  if (child->state == DS_NOTPRESENT)
                          device_probe_and_attach(child);
          }
  }
  
  int
  bus_generic_setup_intr(device_t dev, device_t child, struct resource *irq,
      int flags, driver_intr_t *intr, void *arg, void **cookiep,
      lwkt_serialize_t serializer, const char *desc)
  {
          /* Propagate up the bus hierarchy until someone handles it. */
          if (dev->parent) {
                  return BUS_SETUP_INTR(dev->parent, child, irq, flags,
                      intr, arg, cookiep, serializer, desc);
          } else {
                  return EINVAL;
          }
  }
  
  int
  bus_generic_teardown_intr(device_t dev, device_t child, struct resource *irq,
                            void *cookie)
  {
          /* Propagate up the bus hierarchy until someone handles it. */
          if (dev->parent)
                  return(BUS_TEARDOWN_INTR(dev->parent, child, irq, cookie));
          else
                  return(EINVAL);
  }
  
  int
  bus_generic_disable_intr(device_t dev, device_t child, void *cookie)
  {
          if (dev->parent)
                  return(BUS_DISABLE_INTR(dev->parent, child, cookie));
          else
                  return(0);
  }
  
  void
  bus_generic_enable_intr(device_t dev, device_t child, void *cookie)
  {
          if (dev->parent)
                  BUS_ENABLE_INTR(dev->parent, child, cookie);
  }
  
  int
  bus_generic_config_intr(device_t dev, device_t child, int irq, enum intr_trigger trig,
      enum intr_polarity pol)
  {
          /* Propagate up the bus hierarchy until someone handles it. */
          if (dev->parent)
                  return(BUS_CONFIG_INTR(dev->parent, child, irq, trig, pol));
          else
                  return(EINVAL);
  }
  
  struct resource *
  bus_generic_alloc_resource(device_t dev, device_t child, int type, int *rid,
      u_long start, u_long end, u_long count, u_int flags, int cpuid)
  {
          /* Propagate up the bus hierarchy until someone handles it. */
          if (dev->parent)
                  return(BUS_ALLOC_RESOURCE(dev->parent, child, type, rid, 
                                             start, end, count, flags, cpuid));
          else
                  return(NULL);
  }
  
  int
  bus_generic_release_resource(device_t dev, device_t child, int type, int rid,
                               struct resource *r)
  {
          /* Propagate up the bus hierarchy until someone handles it. */
          if (dev->parent)
                  return(BUS_RELEASE_RESOURCE(dev->parent, child, type, rid, r));
          else
                  return(EINVAL);
  }
  
  int
  bus_generic_activate_resource(device_t dev, device_t child, int type, int rid,
                                struct resource *r)
  {
          /* Propagate up the bus hierarchy until someone handles it. */
          if (dev->parent)
                  return(BUS_ACTIVATE_RESOURCE(dev->parent, child, type, rid, r));
          else
                  return(EINVAL);
  }
  
  int
  bus_generic_deactivate_resource(device_t dev, device_t child, int type,
                                  int rid, struct resource *r)
  {
          /* Propagate up the bus hierarchy until someone handles it. */
          if (dev->parent)
                  return(BUS_DEACTIVATE_RESOURCE(dev->parent, child, type, rid,
                                                 r));
          else
                  return(EINVAL);
  }
  
  int
  bus_generic_get_resource(device_t dev, device_t child, int type, int rid,
                           u_long *startp, u_long *countp)
  {
          int error;
  
          error = ENOENT;
          if (dev->parent) {
                  error = BUS_GET_RESOURCE(dev->parent, child, type, rid, 
                                           startp, countp);
          }
          return (error);
  }
  
  int
  bus_generic_set_resource(device_t dev, device_t child, int type, int rid,
                          u_long start, u_long count, int cpuid)
  {
          int error;
  
          error = EINVAL;
          if (dev->parent) {
                  error = BUS_SET_RESOURCE(dev->parent, child, type, rid, 
                                           start, count, cpuid);
          }
          return (error);
  }
  
  void
  bus_generic_delete_resource(device_t dev, device_t child, int type, int rid)
  {
          if (dev->parent)
                  BUS_DELETE_RESOURCE(dev, child, type, rid);
  }
  
  /**
   * @brief Helper function for implementing BUS_GET_DMA_TAG().
   *
   * This simple implementation of BUS_GET_DMA_TAG() simply calls the
   * BUS_GET_DMA_TAG() method of the parent of @p dev.
   */
  bus_dma_tag_t
  bus_generic_get_dma_tag(device_t dev, device_t child)
  {
  
          /* Propagate up the bus hierarchy until someone handles it. */
          if (dev->parent != NULL)
                  return (BUS_GET_DMA_TAG(dev->parent, child));
          return (NULL);
  }
  
  int
  bus_generic_rl_get_resource(device_t dev, device_t child, int type, int rid,
      u_long *startp, u_long *countp)
  {
          struct resource_list *rl = NULL;
          struct resource_list_entry *rle = NULL;
  
          rl = BUS_GET_RESOURCE_LIST(dev, child);
          if (!rl)
                  return(EINVAL);
  
          rle = resource_list_find(rl, type, rid);
          if (!rle)
                  return(ENOENT);
  
          if (startp)
                  *startp = rle->start;
          if (countp)
                  *countp = rle->count;
  
          return(0);
  }
  
  int
  bus_generic_rl_set_resource(device_t dev, device_t child, int type, int rid,
      u_long start, u_long count, int cpuid)
  {
          struct resource_list *rl = NULL;
  
          rl = BUS_GET_RESOURCE_LIST(dev, child);
          if (!rl)
                  return(EINVAL);
  
          resource_list_add(rl, type, rid, start, (start + count - 1), count,
              cpuid);
  
          return(0);
  }
  
  void
  bus_generic_rl_delete_resource(device_t dev, device_t child, int type, int rid)
  {
          struct resource_list *rl = NULL;
  
          rl = BUS_GET_RESOURCE_LIST(dev, child);
          if (!rl)
                  return;
  
          resource_list_delete(rl, type, rid);
  }
  
  int
  bus_generic_rl_release_resource(device_t dev, device_t child, int type,
      int rid, struct resource *r)
  {
          struct resource_list *rl = NULL;
  
          rl = BUS_GET_RESOURCE_LIST(dev, child);
          if (!rl)
                  return(EINVAL);
  
          return(resource_list_release(rl, dev, child, type, rid, r));
  }
  
  struct resource *
  bus_generic_rl_alloc_resource(device_t dev, device_t child, int type,
      int *rid, u_long start, u_long end, u_long count, u_int flags, int cpuid)
  {
          struct resource_list *rl = NULL;
  
          rl = BUS_GET_RESOURCE_LIST(dev, child);
          if (!rl)
                  return(NULL);
  
          return(resource_list_alloc(rl, dev, child, type, rid,
              start, end, count, flags, cpuid));
  }
  
  int
  bus_generic_child_present(device_t bus, device_t child)
  {
          return(BUS_CHILD_PRESENT(device_get_parent(bus), bus));
  }
  
  
  /*
   * Some convenience functions to make it easier for drivers to use the
   * resource-management functions.  All these really do is hide the
   * indirection through the parent's method table, making for slightly
   * less-wordy code.  In the future, it might make sense for this code
   * to maintain some sort of a list of resources allocated by each device.
   */
  int
  bus_alloc_resources(device_t dev, struct resource_spec *rs,
      struct resource **res)
  {
          int i;
  
          for (i = 0; rs[i].type != -1; i++)
                  res[i] = NULL;
          for (i = 0; rs[i].type != -1; i++) {
                  res[i] = bus_alloc_resource_any(dev,
                      rs[i].type, &rs[i].rid, rs[i].flags);
                  if (res[i] == NULL) {
                          bus_release_resources(dev, rs, res);
                          return (ENXIO);
                  }
          }
          return (0);
  }
  
  void
  bus_release_resources(device_t dev, const struct resource_spec *rs,
      struct resource **res)
  {
          int i;
  
          for (i = 0; rs[i].type != -1; i++)
                  if (res[i] != NULL) {
                          bus_release_resource(
                              dev, rs[i].type, rs[i].rid, res[i]);
                          res[i] = NULL;
                  }
  }
  
  struct resource *
  bus_alloc_resource(device_t dev, int type, int *rid, u_long start, u_long end,
                     u_long count, u_int flags)
  {
          if (dev->parent == NULL)
                  return(0);
          return(BUS_ALLOC_RESOURCE(dev->parent, dev, type, rid, start, end,
                                    count, flags, -1));
  }
  
  struct resource *
  bus_alloc_legacy_irq_resource(device_t dev, int *rid, u_long irq, u_int flags)
  {
          if (dev->parent == NULL)
                  return(0);
          return BUS_ALLOC_RESOURCE(dev->parent, dev, SYS_RES_IRQ, rid,
              irq, irq, 1, flags, machintr_legacy_intr_cpuid(irq));
  }
  
  int
  bus_activate_resource(device_t dev, int type, int rid, struct resource *r)
  {
          if (dev->parent == NULL)
                  return(EINVAL);
          return(BUS_ACTIVATE_RESOURCE(dev->parent, dev, type, rid, r));
  }
  
  int
  bus_deactivate_resource(device_t dev, int type, int rid, struct resource *r)
  {
          if (dev->parent == NULL)
                  return(EINVAL);
          return(BUS_DEACTIVATE_RESOURCE(dev->parent, dev, type, rid, r));
  }
  
  int
  bus_release_resource(device_t dev, int type, int rid, struct resource *r)
  {
          if (dev->parent == NULL)
                  return(EINVAL);
          return(BUS_RELEASE_RESOURCE(dev->parent, dev, type, rid, r));
  }
  
  int
  bus_setup_intr_descr(device_t dev, struct resource *r, int flags,
      driver_intr_t handler, void *arg, void **cookiep,
      lwkt_serialize_t serializer, const char *desc)
  {
          if (dev->parent == NULL)
                  return EINVAL;
          return BUS_SETUP_INTR(dev->parent, dev, r, flags, handler, arg,
              cookiep, serializer, desc);
  }
  
  int
  bus_setup_intr(device_t dev, struct resource *r, int flags,
      driver_intr_t handler, void *arg, void **cookiep,
      lwkt_serialize_t serializer)
  {
          return bus_setup_intr_descr(dev, r, flags, handler, arg, cookiep,
              serializer, NULL);
  }
  
  int
  bus_teardown_intr(device_t dev, struct resource *r, void *cookie)
  {
          if (dev->parent == NULL)
                  return(EINVAL);
          return(BUS_TEARDOWN_INTR(dev->parent, dev, r, cookie));
  }
  
  void
  bus_enable_intr(device_t dev, void *cookie)
  {
          if (dev->parent)
                  BUS_ENABLE_INTR(dev->parent, dev, cookie);
  }
  
  int
  bus_disable_intr(device_t dev, void *cookie)
  {
          if (dev->parent)
                  return(BUS_DISABLE_INTR(dev->parent, dev, cookie));
          else
                  return(0);
  }
  
  int
  bus_set_resource(device_t dev, int type, int rid,
                   u_long start, u_long count, int cpuid)
  {
          return(BUS_SET_RESOURCE(device_get_parent(dev), dev, type, rid,
                                  start, count, cpuid));
  }
  
  int
  bus_get_resource(device_t dev, int type, int rid,
                   u_long *startp, u_long *countp)
  {
          return(BUS_GET_RESOURCE(device_get_parent(dev), dev, type, rid,
                                  startp, countp));
  }
  
  u_long
  bus_get_resource_start(device_t dev, int type, int rid)
  {
          u_long start, count;
          int error;
  
          error = BUS_GET_RESOURCE(device_get_parent(dev), dev, type, rid,
                                   &start, &count);
          if (error)
                  return(0);
          return(start);
  }
  
  u_long
  bus_get_resource_count(device_t dev, int type, int rid)
  {
          u_long start, count;
          int error;
  
          error = BUS_GET_RESOURCE(device_get_parent(dev), dev, type, rid,
                                   &start, &count);
          if (error)
                  return(0);
          return(count);
  }
  
  void
  bus_delete_resource(device_t dev, int type, int rid)
  {
          BUS_DELETE_RESOURCE(device_get_parent(dev), dev, type, rid);
  }
  
  int
  bus_child_present(device_t child)
  {
          return (BUS_CHILD_PRESENT(device_get_parent(child), child));
  }
  
  int
  bus_child_pnpinfo_str(device_t child, char *buf, size_t buflen)
  {
          device_t parent;
  
          parent = device_get_parent(child);
          if (parent == NULL) {
                  *buf = '\0';
                  return (0);
          }
          return (BUS_CHILD_PNPINFO_STR(parent, child, buf, buflen));
  }
  
  int
  bus_child_location_str(device_t child, char *buf, size_t buflen)
  {
          device_t parent;
  
          parent = device_get_parent(child);
          if (parent == NULL) {
                  *buf = '\0';
                  return (0);
          }
          return (BUS_CHILD_LOCATION_STR(parent, child, buf, buflen));
  }
  
  /**
   * @brief Wrapper function for BUS_GET_DMA_TAG().
   *
   * This function simply calls the BUS_GET_DMA_TAG() method of the
   * parent of @p dev.
   */
  bus_dma_tag_t
  bus_get_dma_tag(device_t dev)
  {
          device_t parent;
  
          parent = device_get_parent(dev);
          if (parent == NULL)
                  return (NULL);
          return (BUS_GET_DMA_TAG(parent, dev));
  }
  
  static int
  root_print_child(device_t dev, device_t child)
  {
          return(0);
  }
  
  static int
  root_setup_intr(device_t dev, device_t child, driver_intr_t *intr, void *arg,
                  void **cookiep, lwkt_serialize_t serializer, const char *desc)
  {
          /*
           * If an interrupt mapping gets to here something bad has happened.
           */
          panic("root_setup_intr");
  }
  
  /*
   * If we get here, assume that the device is permanant and really is
   * present in the system.  Removable bus drivers are expected to intercept
   * this call long before it gets here.  We return -1 so that drivers that
   * really care can check vs -1 or some ERRNO returned higher in the food
   * chain.
   */
  static int
  root_child_present(device_t dev, device_t child)
  {
          return(-1);
  }
  
  /*
   * XXX NOTE! other defaults may be set in bus_if.m
   */
  static kobj_method_t root_methods[] = {
          /* Device interface */
          KOBJMETHOD(device_shutdown,     bus_generic_shutdown),
          KOBJMETHOD(device_suspend,      bus_generic_suspend),
          KOBJMETHOD(device_resume,       bus_generic_resume),
  
          /* Bus interface */
          KOBJMETHOD(bus_add_child,       bus_generic_add_child),
          KOBJMETHOD(bus_print_child,     root_print_child),
          KOBJMETHOD(bus_read_ivar,       bus_generic_read_ivar),
          KOBJMETHOD(bus_write_ivar,      bus_generic_write_ivar),
          KOBJMETHOD(bus_setup_intr,      root_setup_intr),
          KOBJMETHOD(bus_child_present,   root_child_present),
  
          KOBJMETHOD_END
  };
  
  static driver_t root_driver = {
          "root",
          root_methods,
          1,                      /* no softc */
  };
  
  device_t        root_bus;
  devclass_t      root_devclass;
  
  static int
  root_bus_module_handler(module_t mod, int what, void* arg)
  {
          switch (what) {
          case MOD_LOAD:
                  TAILQ_INIT(&bus_data_devices);
                  root_bus = make_device(NULL, "root", 0);
                  root_bus->desc = "System root bus";
                  kobj_init((kobj_t) root_bus, (kobj_class_t) &root_driver);
                  root_bus->driver = &root_driver;
                  root_bus->state = DS_ALIVE;
                  root_devclass = devclass_find_internal("root", NULL, FALSE);
                  devinit();
                  return(0);
  
          case MOD_SHUTDOWN:
                  device_shutdown(root_bus);
                  return(0);
          default:
                  return(0);
          }
  }
  
  static moduledata_t root_bus_mod = {
          "rootbus",
          root_bus_module_handler,
          0
  };
  DECLARE_MODULE(rootbus, root_bus_mod, SI_SUB_DRIVERS, SI_ORDER_FIRST);
  
  void
  root_bus_configure(void)
  {
          int warncount;
          device_t dev;
  
          PDEBUG(("."));
  
          /*
           * handle device_identify based device attachments to the root_bus
           * (typically nexus).
           */
          bus_generic_probe(root_bus);
  
          /*
           * Probe and attach the devices under root_bus.
           */
          TAILQ_FOREACH(dev, &root_bus->children, link) {
                  device_probe_and_attach(dev);
          }
  
          /*
           * Wait for all asynchronous attaches to complete.  If we don't
           * our legacy ISA bus scan could steal device unit numbers or
           * even I/O ports.
           */
          warncount = 10;
          if (numasyncthreads)
                  kprintf("Waiting for async drivers to attach\n");
          while (numasyncthreads > 0) {
                  if (tsleep(&numasyncthreads, 0, "rootbus", hz) == EWOULDBLOCK)
                          --warncount;
                  if (warncount == 0) {
                          kprintf("Warning: Still waiting for %d "
                                  "drivers to attach\n", numasyncthreads);
                  } else if (warncount == -30) {
                          kprintf("Giving up on %d drivers\n", numasyncthreads);
                          break;
                  }
          }
          root_bus->state = DS_ATTACHED;
  }
  
  int
  driver_module_handler(module_t mod, int what, void *arg)
  {
          int error;
          struct driver_module_data *dmd;
          devclass_t bus_devclass;
          kobj_class_t driver;
          const char *parentname;
  
          dmd = (struct driver_module_data *)arg;
          bus_devclass = devclass_find_internal(dmd->dmd_busname, NULL, TRUE);
          error = 0;
  
          switch (what) {
          case MOD_LOAD:
                  if (dmd->dmd_chainevh)
                          error = dmd->dmd_chainevh(mod,what,dmd->dmd_chainarg);
  
                  driver = dmd->dmd_driver;
                  PDEBUG(("Loading module: driver %s on bus %s",
                          DRIVERNAME(driver), dmd->dmd_busname));
  
                  /*
                   * If the driver has any base classes, make the
                   * devclass inherit from the devclass of the driver's
                   * first base class. This will allow the system to
                   * search for drivers in both devclasses for children
                   * of a device using this driver.
                   */
                  if (driver->baseclasses)
                          parentname = driver->baseclasses[0]->name;
                  else
                          parentname = NULL;
                  *dmd->dmd_devclass = devclass_find_internal(driver->name,
                                                              parentname, TRUE);
  
                  error = devclass_add_driver(bus_devclass, driver);
                  if (error)
                          break;
                  break;
  
          case MOD_UNLOAD:
                  PDEBUG(("Unloading module: driver %s from bus %s",
                          DRIVERNAME(dmd->dmd_driver), dmd->dmd_busname));
                  error = devclass_delete_driver(bus_devclass, dmd->dmd_driver);
  
                  if (!error && dmd->dmd_chainevh)
                          error = dmd->dmd_chainevh(mod,what,dmd->dmd_chainarg);
                  break;
          }
  
          return (error);
  }
  
  #ifdef BUS_DEBUG
  
  /*
   * The _short versions avoid iteration by not calling anything that prints
   * more than oneliners. I love oneliners.
   */
  
  static void
  print_device_short(device_t dev, int indent)
  {
          if (!dev)
                  return;
  
          indentprintf(("device %d: <%s> %sparent,%schildren,%s%s%s%s,%sivars,%ssoftc,busy=%d\n",
                        dev->unit, dev->desc,
                        (dev->parent? "":"no "),
                        (TAILQ_EMPTY(&dev->children)? "no ":""),
                        (dev->flags&DF_ENABLED? "enabled,":"disabled,"),
                        (dev->flags&DF_FIXEDCLASS? "fixed,":""),
                        (dev->flags&DF_WILDCARD? "wildcard,":""),
                        (dev->flags&DF_DESCMALLOCED? "descmalloced,":""),
                        (dev->ivars? "":"no "),
                        (dev->softc? "":"no "),
                        dev->busy));
  }
  
  static void
  print_device(device_t dev, int indent)
  {
          if (!dev)
                  return;
  
          print_device_short(dev, indent);
  
          indentprintf(("Parent:\n"));
          print_device_short(dev->parent, indent+1);
          indentprintf(("Driver:\n"));
          print_driver_short(dev->driver, indent+1);
          indentprintf(("Devclass:\n"));
          print_devclass_short(dev->devclass, indent+1);
  }
  
  /*
   * Print the device and all its children (indented).
   */
  void
  print_device_tree_short(device_t dev, int indent)
  {
          device_t child;
  
          if (!dev)
                  return;
  
          print_device_short(dev, indent);
  
          TAILQ_FOREACH(child, &dev->children, link)
                  print_device_tree_short(child, indent+1);
  }
  
  /*
   * Print the device and all its children (indented).
   */
  void
  print_device_tree(device_t dev, int indent)
  {
          device_t child;
  
          if (!dev)
                  return;
  
          print_device(dev, indent);
  
          TAILQ_FOREACH(child, &dev->children, link)
                  print_device_tree(child, indent+1);
  }
  
  static void
  print_driver_short(driver_t *driver, int indent)
  {
          if (!driver)
                  return;
  
          indentprintf(("driver %s: softc size = %zu\n",
                        driver->name, driver->size));
  }
  
  static void
  print_driver(driver_t *driver, int indent)
  {
          if (!driver)
                  return;
  
          print_driver_short(driver, indent);
  }
  
  
  static void
  print_driver_list(driver_list_t drivers, int indent)
  {
          driverlink_t driver;
  
          TAILQ_FOREACH(driver, &drivers, link)
                  print_driver(driver->driver, indent);
  }
  
  static void
  print_devclass_short(devclass_t dc, int indent)
  {
          if (!dc)
                  return;
  
          indentprintf(("devclass %s: max units = %d\n", dc->name, dc->maxunit));
  }
  
  static void
  print_devclass(devclass_t dc, int indent)
  {
          int i;
  
          if (!dc)
                  return;
  
          print_devclass_short(dc, indent);
          indentprintf(("Drivers:\n"));
          print_driver_list(dc->drivers, indent+1);
  
          indentprintf(("Devices:\n"));
          for (i = 0; i < dc->maxunit; i++)
                  if (dc->devices[i])
                          print_device(dc->devices[i], indent+1);
  }
  
  void
  print_devclass_list_short(void)
  {
          devclass_t dc;
  
          kprintf("Short listing of devclasses, drivers & devices:\n");
          TAILQ_FOREACH(dc, &devclasses, link) {
                  print_devclass_short(dc, 0);
          }
  }
  
  void
  print_devclass_list(void)
  {
          devclass_t dc;
  
          kprintf("Full listing of devclasses, drivers & devices:\n");
          TAILQ_FOREACH(dc, &devclasses, link) {
                  print_devclass(dc, 0);
          }
  }
  
  #endif
  
  /*
   * Check to see if a device is disabled via a disabled hint.
   */
  int
  resource_disabled(const char *name, int unit)
  {
          int error, value;
  
          error = resource_int_value(name, unit, "disabled", &value);
          if (error)
                 return(0);
          return(value);
  }
  
  /*
   * User-space access to the device tree.
   *
   * We implement a small set of nodes:
   *
   * hw.bus                       Single integer read method to obtain the
   *                              current generation count.
   * hw.bus.devices               Reads the entire device tree in flat space.
   * hw.bus.rman                  Resource manager interface
   *
   * We might like to add the ability to scan devclasses and/or drivers to
   * determine what else is currently loaded/available.
   */
  
  static int
  sysctl_bus(SYSCTL_HANDLER_ARGS)
  {
          struct u_businfo        ubus;
  
          ubus.ub_version = BUS_USER_VERSION;
          ubus.ub_generation = bus_data_generation;
  
          return (SYSCTL_OUT(req, &ubus, sizeof(ubus)));
  }
  SYSCTL_NODE(_hw_bus, OID_AUTO, info, CTLFLAG_RW, sysctl_bus,
      "bus-related data");
  
  static int
  sysctl_devices(SYSCTL_HANDLER_ARGS)
  {
          int                     *name = (int *)arg1;
          u_int                   namelen = arg2;
          int                     index;
          struct device           *dev;
          struct u_device         udev;   /* XXX this is a bit big */
          int                     error;
  
          if (namelen != 2)
                  return (EINVAL);
  
          if (bus_data_generation_check(name[0]))
                  return (EINVAL);
  
          index = name[1];
  
          /*
           * Scan the list of devices, looking for the requested index.
           */
          TAILQ_FOREACH(dev, &bus_data_devices, devlink) {
                  if (index-- == 0)
                          break;
          }
          if (dev == NULL)
                  return (ENOENT);
  
          /*
           * Populate the return array.
           */
          bzero(&udev, sizeof(udev));
          udev.dv_handle = (uintptr_t)dev;
          udev.dv_parent = (uintptr_t)dev->parent;
          if (dev->nameunit != NULL)
                  strlcpy(udev.dv_name, dev->nameunit, sizeof(udev.dv_name));
          if (dev->desc != NULL)
                  strlcpy(udev.dv_desc, dev->desc, sizeof(udev.dv_desc));
          if (dev->driver != NULL && dev->driver->name != NULL)
                  strlcpy(udev.dv_drivername, dev->driver->name,
                      sizeof(udev.dv_drivername));
          bus_child_pnpinfo_str(dev, udev.dv_pnpinfo, sizeof(udev.dv_pnpinfo));
          bus_child_location_str(dev, udev.dv_location, sizeof(udev.dv_location));
          udev.dv_devflags = dev->devflags;
          udev.dv_flags = dev->flags;
          udev.dv_state = dev->state;
          error = SYSCTL_OUT(req, &udev, sizeof(udev));
          return (error);
  }
  
  SYSCTL_NODE(_hw_bus, OID_AUTO, devices, CTLFLAG_RD, sysctl_devices,
      "system device tree");
  
  int
  bus_data_generation_check(int generation)
  {
          if (generation != bus_data_generation)
                  return (1);
  
          /* XXX generate optimised lists here? */
          return (0);
  }
  
  void
  bus_data_generation_update(void)
  {
          bus_data_generation++;
  }
  
  const char *
  intr_str_polarity(enum intr_polarity pola)
  {
          switch (pola) {
          case INTR_POLARITY_LOW:
                  return "low";
  
          case INTR_POLARITY_HIGH:
                  return "high";
  
          case INTR_POLARITY_CONFORM:
                  return "conform";
          }
          return "unknown";
  }
  
  const char *
  intr_str_trigger(enum intr_trigger trig)
  {
          switch (trig) {
          case INTR_TRIGGER_EDGE:
                  return "edge";
  
          case INTR_TRIGGER_LEVEL:
                  return "level";
  
          case INTR_TRIGGER_CONFORM:
                  return "conform";
          }
          return "unknown";
  }
  
  int
  device_getenv_int(device_t dev, const char *knob, int def)
  {
          char env[128];
  
          ksnprintf(env, sizeof(env), "hw.%s.%s", device_get_nameunit(dev), knob);
          kgetenv_int(env, &def);
          return def;
  }

Cache object: 6cc0dd09db8add64a56a29f44a2e6e2a