1 /******************************************************************************
2 * Talks to Xen Store to figure out what devices we have.
4 * Copyright (C) 2005 Rusty Russell, IBM Corporation
5 * Copyright (C) 2005 Mike Wray, Hewlett-Packard
6 * Copyright (C) 2005, 2006 XenSource Ltd
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License version 2
10 * as published by the Free Software Foundation; or, when distributed
11 * separately from the Linux kernel or incorporated into other
12 * software packages, subject to the following license:
14 * Permission is hereby granted, free of charge, to any person obtaining a copy
15 * of this source file (the "Software"), to deal in the Software without
16 * restriction, including without limitation the rights to use, copy, modify,
17 * merge, publish, distribute, sublicense, and/or sell copies of the Software,
18 * and to permit persons to whom the Software is furnished to do so, subject to
19 * the following conditions:
21 * The above copyright notice and this permission notice shall be included in
22 * all copies or substantial portions of the Software.
24 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
25 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
26 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
27 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
28 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
29 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
33 #define DPRINTK(fmt, args...) \
34 pr_debug("xenbus_probe (%s:%d) " fmt ".\n", \
35 __func__, __LINE__, ##args)
37 #include <linux/kernel.h>
38 #include <linux/err.h>
39 #include <linux/string.h>
40 #include <linux/ctype.h>
41 #include <linux/fcntl.h>
43 #include <linux/proc_fs.h>
44 #include <linux/notifier.h>
45 #include <linux/kthread.h>
46 #include <linux/mutex.h>
48 #include <linux/slab.h>
51 #include <asm/pgtable.h>
52 #include <asm/xen/hypervisor.h>
55 #include <xen/xenbus.h>
56 #include <xen/events.h>
61 #include "xenbus_comms.h"
62 #include "xenbus_probe.h"
66 EXPORT_SYMBOL(xen_store_evtchn);
68 struct xenstore_domain_interface *xen_store_interface;
69 static unsigned long xen_store_mfn;
71 static BLOCKING_NOTIFIER_HEAD(xenstore_chain);
73 static void wait_for_devices(struct xenbus_driver *xendrv);
75 static int xenbus_probe_frontend(const char *type, const char *name);
77 static void xenbus_dev_shutdown(struct device *_dev);
79 static int xenbus_dev_suspend(struct device *dev, pm_message_t state);
80 static int xenbus_dev_resume(struct device *dev);
82 /* If something in array of ids matches this device, return it. */
83 static const struct xenbus_device_id *
84 match_device(const struct xenbus_device_id *arr, struct xenbus_device *dev)
86 for (; *arr->devicetype != '\0'; arr++) {
87 if (!strcmp(arr->devicetype, dev->devicetype))
93 int xenbus_match(struct device *_dev, struct device_driver *_drv)
95 struct xenbus_driver *drv = to_xenbus_driver(_drv);
100 return match_device(drv->ids, to_xenbus_device(_dev)) != NULL;
103 static int xenbus_uevent(struct device *_dev, struct kobj_uevent_env *env)
105 struct xenbus_device *dev = to_xenbus_device(_dev);
107 if (add_uevent_var(env, "MODALIAS=xen:%s", dev->devicetype))
113 /* device/<type>/<id> => <type>-<id> */
114 static int frontend_bus_id(char bus_id[XEN_BUS_ID_SIZE], const char *nodename)
116 nodename = strchr(nodename, '/');
117 if (!nodename || strlen(nodename + 1) >= XEN_BUS_ID_SIZE) {
118 printk(KERN_WARNING "XENBUS: bad frontend %s\n", nodename);
122 strlcpy(bus_id, nodename + 1, XEN_BUS_ID_SIZE);
123 if (!strchr(bus_id, '/')) {
124 printk(KERN_WARNING "XENBUS: bus_id %s no slash\n", bus_id);
127 *strchr(bus_id, '/') = '-';
132 static void free_otherend_details(struct xenbus_device *dev)
134 kfree(dev->otherend);
135 dev->otherend = NULL;
139 static void free_otherend_watch(struct xenbus_device *dev)
141 if (dev->otherend_watch.node) {
142 unregister_xenbus_watch(&dev->otherend_watch);
143 kfree(dev->otherend_watch.node);
144 dev->otherend_watch.node = NULL;
149 int read_otherend_details(struct xenbus_device *xendev,
150 char *id_node, char *path_node)
152 int err = xenbus_gather(XBT_NIL, xendev->nodename,
153 id_node, "%i", &xendev->otherend_id,
154 path_node, NULL, &xendev->otherend,
157 xenbus_dev_fatal(xendev, err,
158 "reading other end details from %s",
162 if (strlen(xendev->otherend) == 0 ||
163 !xenbus_exists(XBT_NIL, xendev->otherend, "")) {
164 xenbus_dev_fatal(xendev, -ENOENT,
165 "unable to read other end from %s. "
166 "missing or inaccessible.",
168 free_otherend_details(xendev);
176 static int read_backend_details(struct xenbus_device *xendev)
178 return read_otherend_details(xendev, "backend-id", "backend");
181 static struct device_attribute xenbus_dev_attrs[] = {
185 /* Bus type for frontend drivers. */
186 static struct xen_bus_type xenbus_frontend = {
188 .levels = 2, /* device/type/<id> */
189 .get_bus_id = frontend_bus_id,
190 .probe = xenbus_probe_frontend,
193 .match = xenbus_match,
194 .uevent = xenbus_uevent,
195 .probe = xenbus_dev_probe,
196 .remove = xenbus_dev_remove,
197 .shutdown = xenbus_dev_shutdown,
198 .dev_attrs = xenbus_dev_attrs,
200 .suspend = xenbus_dev_suspend,
201 .resume = xenbus_dev_resume,
205 static void otherend_changed(struct xenbus_watch *watch,
206 const char **vec, unsigned int len)
208 struct xenbus_device *dev =
209 container_of(watch, struct xenbus_device, otherend_watch);
210 struct xenbus_driver *drv = to_xenbus_driver(dev->dev.driver);
211 enum xenbus_state state;
213 /* Protect us against watches firing on old details when the otherend
214 details change, say immediately after a resume. */
215 if (!dev->otherend ||
216 strncmp(dev->otherend, vec[XS_WATCH_PATH],
217 strlen(dev->otherend))) {
218 dev_dbg(&dev->dev, "Ignoring watch at %s\n",
223 state = xenbus_read_driver_state(dev->otherend);
225 dev_dbg(&dev->dev, "state is %d, (%s), %s, %s\n",
226 state, xenbus_strstate(state), dev->otherend_watch.node,
230 * Ignore xenbus transitions during shutdown. This prevents us doing
231 * work that can fail e.g., when the rootfs is gone.
233 if (system_state > SYSTEM_RUNNING) {
234 struct xen_bus_type *bus = bus;
235 bus = container_of(dev->dev.bus, struct xen_bus_type, bus);
236 /* If we're frontend, drive the state machine to Closed. */
237 /* This should cause the backend to release our resources. */
238 if ((bus == &xenbus_frontend) && (state == XenbusStateClosing))
239 xenbus_frontend_closed(dev);
243 if (drv->otherend_changed)
244 drv->otherend_changed(dev, state);
248 static int talk_to_otherend(struct xenbus_device *dev)
250 struct xenbus_driver *drv = to_xenbus_driver(dev->dev.driver);
252 free_otherend_watch(dev);
253 free_otherend_details(dev);
255 return drv->read_otherend_details(dev);
259 static int watch_otherend(struct xenbus_device *dev)
261 return xenbus_watch_pathfmt(dev, &dev->otherend_watch, otherend_changed,
262 "%s/%s", dev->otherend, "state");
266 int xenbus_dev_probe(struct device *_dev)
268 struct xenbus_device *dev = to_xenbus_device(_dev);
269 struct xenbus_driver *drv = to_xenbus_driver(_dev->driver);
270 const struct xenbus_device_id *id;
273 DPRINTK("%s", dev->nodename);
280 id = match_device(drv->ids, dev);
286 err = talk_to_otherend(dev);
288 dev_warn(&dev->dev, "talk_to_otherend on %s failed.\n",
293 err = drv->probe(dev, id);
297 err = watch_otherend(dev);
299 dev_warn(&dev->dev, "watch_otherend on %s failed.\n",
306 xenbus_dev_error(dev, err, "xenbus_dev_probe on %s", dev->nodename);
307 xenbus_switch_state(dev, XenbusStateClosed);
311 int xenbus_dev_remove(struct device *_dev)
313 struct xenbus_device *dev = to_xenbus_device(_dev);
314 struct xenbus_driver *drv = to_xenbus_driver(_dev->driver);
316 DPRINTK("%s", dev->nodename);
318 free_otherend_watch(dev);
319 free_otherend_details(dev);
324 xenbus_switch_state(dev, XenbusStateClosed);
328 static void xenbus_dev_shutdown(struct device *_dev)
330 struct xenbus_device *dev = to_xenbus_device(_dev);
331 unsigned long timeout = 5*HZ;
333 DPRINTK("%s", dev->nodename);
335 get_device(&dev->dev);
336 if (dev->state != XenbusStateConnected) {
337 printk(KERN_INFO "%s: %s: %s != Connected, skipping\n", __func__,
338 dev->nodename, xenbus_strstate(dev->state));
341 xenbus_switch_state(dev, XenbusStateClosing);
342 timeout = wait_for_completion_timeout(&dev->down, timeout);
344 printk(KERN_INFO "%s: %s timeout closing device\n",
345 __func__, dev->nodename);
347 put_device(&dev->dev);
350 int xenbus_register_driver_common(struct xenbus_driver *drv,
351 struct xen_bus_type *bus,
352 struct module *owner,
353 const char *mod_name)
355 drv->driver.name = drv->name;
356 drv->driver.bus = &bus->bus;
357 drv->driver.owner = owner;
358 drv->driver.mod_name = mod_name;
360 return driver_register(&drv->driver);
363 int __xenbus_register_frontend(struct xenbus_driver *drv,
364 struct module *owner, const char *mod_name)
368 drv->read_otherend_details = read_backend_details;
370 ret = xenbus_register_driver_common(drv, &xenbus_frontend,
375 /* If this driver is loaded as a module wait for devices to attach. */
376 wait_for_devices(drv);
380 EXPORT_SYMBOL_GPL(__xenbus_register_frontend);
382 void xenbus_unregister_driver(struct xenbus_driver *drv)
384 driver_unregister(&drv->driver);
386 EXPORT_SYMBOL_GPL(xenbus_unregister_driver);
390 struct xenbus_device *dev;
391 const char *nodename;
394 static int cmp_dev(struct device *dev, void *data)
396 struct xenbus_device *xendev = to_xenbus_device(dev);
397 struct xb_find_info *info = data;
399 if (!strcmp(xendev->nodename, info->nodename)) {
407 struct xenbus_device *xenbus_device_find(const char *nodename,
408 struct bus_type *bus)
410 struct xb_find_info info = { .dev = NULL, .nodename = nodename };
412 bus_for_each_dev(bus, NULL, &info, cmp_dev);
416 static int cleanup_dev(struct device *dev, void *data)
418 struct xenbus_device *xendev = to_xenbus_device(dev);
419 struct xb_find_info *info = data;
420 int len = strlen(info->nodename);
422 DPRINTK("%s", info->nodename);
424 /* Match the info->nodename path, or any subdirectory of that path. */
425 if (strncmp(xendev->nodename, info->nodename, len))
428 /* If the node name is longer, ensure it really is a subdirectory. */
429 if ((strlen(xendev->nodename) > len) && (xendev->nodename[len] != '/'))
437 static void xenbus_cleanup_devices(const char *path, struct bus_type *bus)
439 struct xb_find_info info = { .nodename = path };
443 bus_for_each_dev(bus, NULL, &info, cleanup_dev);
445 device_unregister(&info.dev->dev);
446 put_device(&info.dev->dev);
451 static void xenbus_dev_release(struct device *dev)
454 kfree(to_xenbus_device(dev));
457 static ssize_t xendev_show_nodename(struct device *dev,
458 struct device_attribute *attr, char *buf)
460 return sprintf(buf, "%s\n", to_xenbus_device(dev)->nodename);
462 static DEVICE_ATTR(nodename, S_IRUSR | S_IRGRP | S_IROTH, xendev_show_nodename, NULL);
464 static ssize_t xendev_show_devtype(struct device *dev,
465 struct device_attribute *attr, char *buf)
467 return sprintf(buf, "%s\n", to_xenbus_device(dev)->devicetype);
469 static DEVICE_ATTR(devtype, S_IRUSR | S_IRGRP | S_IROTH, xendev_show_devtype, NULL);
471 static ssize_t xendev_show_modalias(struct device *dev,
472 struct device_attribute *attr, char *buf)
474 return sprintf(buf, "xen:%s\n", to_xenbus_device(dev)->devicetype);
476 static DEVICE_ATTR(modalias, S_IRUSR | S_IRGRP | S_IROTH, xendev_show_modalias, NULL);
478 int xenbus_probe_node(struct xen_bus_type *bus,
480 const char *nodename)
482 char devname[XEN_BUS_ID_SIZE];
484 struct xenbus_device *xendev;
488 enum xenbus_state state = xenbus_read_driver_state(nodename);
490 if (state != XenbusStateInitialising) {
491 /* Device is not new, so ignore it. This can happen if a
492 device is going away after switching to Closed. */
496 stringlen = strlen(nodename) + 1 + strlen(type) + 1;
497 xendev = kzalloc(sizeof(*xendev) + stringlen, GFP_KERNEL);
501 xendev->state = XenbusStateInitialising;
503 /* Copy the strings into the extra space. */
505 tmpstring = (char *)(xendev + 1);
506 strcpy(tmpstring, nodename);
507 xendev->nodename = tmpstring;
509 tmpstring += strlen(tmpstring) + 1;
510 strcpy(tmpstring, type);
511 xendev->devicetype = tmpstring;
512 init_completion(&xendev->down);
514 xendev->dev.bus = &bus->bus;
515 xendev->dev.release = xenbus_dev_release;
517 err = bus->get_bus_id(devname, xendev->nodename);
521 dev_set_name(&xendev->dev, devname);
523 /* Register with generic device framework. */
524 err = device_register(&xendev->dev);
528 err = device_create_file(&xendev->dev, &dev_attr_nodename);
530 goto fail_unregister;
532 err = device_create_file(&xendev->dev, &dev_attr_devtype);
534 goto fail_remove_nodename;
536 err = device_create_file(&xendev->dev, &dev_attr_modalias);
538 goto fail_remove_devtype;
542 device_remove_file(&xendev->dev, &dev_attr_devtype);
543 fail_remove_nodename:
544 device_remove_file(&xendev->dev, &dev_attr_nodename);
546 device_unregister(&xendev->dev);
552 /* device/<typename>/<name> */
553 static int xenbus_probe_frontend(const char *type, const char *name)
558 nodename = kasprintf(GFP_KERNEL, "%s/%s/%s",
559 xenbus_frontend.root, type, name);
563 DPRINTK("%s", nodename);
565 err = xenbus_probe_node(&xenbus_frontend, type, nodename);
570 static int xenbus_probe_device_type(struct xen_bus_type *bus, const char *type)
574 unsigned int dir_n = 0;
577 dir = xenbus_directory(XBT_NIL, bus->root, type, &dir_n);
581 for (i = 0; i < dir_n; i++) {
582 err = bus->probe(type, dir[i]);
590 int xenbus_probe_devices(struct xen_bus_type *bus)
594 unsigned int i, dir_n;
596 dir = xenbus_directory(XBT_NIL, bus->root, "", &dir_n);
600 for (i = 0; i < dir_n; i++) {
601 err = xenbus_probe_device_type(bus, dir[i]);
609 static unsigned int char_count(const char *str, char c)
611 unsigned int i, ret = 0;
613 for (i = 0; str[i]; i++)
619 static int strsep_len(const char *str, char c, unsigned int len)
623 for (i = 0; str[i]; i++)
629 return (len == 0) ? i : -ERANGE;
632 void xenbus_dev_changed(const char *node, struct xen_bus_type *bus)
635 struct xenbus_device *dev;
636 char type[XEN_BUS_ID_SIZE];
637 const char *p, *root;
639 if (char_count(node, '/') < 2)
642 exists = xenbus_exists(XBT_NIL, node, "");
644 xenbus_cleanup_devices(node, &bus->bus);
648 /* backend/<type>/... or device/<type>/... */
649 p = strchr(node, '/') + 1;
650 snprintf(type, XEN_BUS_ID_SIZE, "%.*s", (int)strcspn(p, "/"), p);
651 type[XEN_BUS_ID_SIZE-1] = '\0';
653 rootlen = strsep_len(node, '/', bus->levels);
656 root = kasprintf(GFP_KERNEL, "%.*s", rootlen, node);
660 dev = xenbus_device_find(root, &bus->bus);
662 xenbus_probe_node(bus, type, root);
664 put_device(&dev->dev);
668 EXPORT_SYMBOL_GPL(xenbus_dev_changed);
670 static void frontend_changed(struct xenbus_watch *watch,
671 const char **vec, unsigned int len)
675 xenbus_dev_changed(vec[XS_WATCH_PATH], &xenbus_frontend);
678 /* We watch for devices appearing and vanishing. */
679 static struct xenbus_watch fe_watch = {
681 .callback = frontend_changed,
684 static int xenbus_dev_suspend(struct device *dev, pm_message_t state)
687 struct xenbus_driver *drv;
688 struct xenbus_device *xdev;
692 if (dev->driver == NULL)
694 drv = to_xenbus_driver(dev->driver);
695 xdev = container_of(dev, struct xenbus_device, dev);
697 err = drv->suspend(xdev, state);
700 "xenbus: suspend %s failed: %i\n", dev_name(dev), err);
704 static int xenbus_dev_resume(struct device *dev)
707 struct xenbus_driver *drv;
708 struct xenbus_device *xdev;
712 if (dev->driver == NULL)
715 drv = to_xenbus_driver(dev->driver);
716 xdev = container_of(dev, struct xenbus_device, dev);
718 err = talk_to_otherend(xdev);
721 "xenbus: resume (talk_to_otherend) %s failed: %i\n",
726 xdev->state = XenbusStateInitialising;
729 err = drv->resume(xdev);
732 "xenbus: resume %s failed: %i\n",
738 err = watch_otherend(xdev);
741 "xenbus_probe: resume (watch_otherend) %s failed: "
742 "%d.\n", dev_name(dev), err);
749 /* A flag to determine if xenstored is 'ready' (i.e. has started) */
750 int xenstored_ready = 0;
753 int register_xenstore_notifier(struct notifier_block *nb)
757 if (xenstored_ready > 0)
758 ret = nb->notifier_call(nb, 0, NULL);
760 blocking_notifier_chain_register(&xenstore_chain, nb);
764 EXPORT_SYMBOL_GPL(register_xenstore_notifier);
766 void unregister_xenstore_notifier(struct notifier_block *nb)
768 blocking_notifier_chain_unregister(&xenstore_chain, nb);
770 EXPORT_SYMBOL_GPL(unregister_xenstore_notifier);
772 void xenbus_probe(struct work_struct *unused)
774 BUG_ON((xenstored_ready <= 0));
776 /* Enumerate devices in xenstore and watch for changes. */
777 xenbus_probe_devices(&xenbus_frontend);
778 register_xenbus_watch(&fe_watch);
779 xenbus_backend_probe_and_watch();
781 /* Notify others that xenstore is up */
782 blocking_notifier_call_chain(&xenstore_chain, 0, NULL);
785 static int __init xenbus_probe_init(void)
795 /* Register ourselves with the kernel bus subsystem */
796 err = bus_register(&xenbus_frontend.bus);
800 err = xenbus_backend_bus_register();
802 goto out_unreg_front;
805 * Domain0 doesn't have a store_evtchn or store_mfn yet.
807 if (xen_initial_domain()) {
808 /* dom0 not yet supported */
810 if (xen_hvm_domain()) {
812 err = hvm_get_parameter(HVM_PARAM_STORE_EVTCHN, &v);
815 xen_store_evtchn = (int)v;
816 err = hvm_get_parameter(HVM_PARAM_STORE_PFN, &v);
819 xen_store_mfn = (unsigned long)v;
820 xen_store_interface = ioremap(xen_store_mfn << PAGE_SHIFT, PAGE_SIZE);
822 xen_store_evtchn = xen_start_info->store_evtchn;
823 xen_store_mfn = xen_start_info->store_mfn;
824 xen_store_interface = mfn_to_virt(xen_store_mfn);
829 /* Initialize the interface to xenstore. */
833 "XENBUS: Error initializing xenstore comms: %i\n", err);
837 if (!xen_initial_domain())
840 #ifdef CONFIG_XEN_COMPAT_XENFS
842 * Create xenfs mountpoint in /proc for compatibility with
843 * utilities that expect to find "xenbus" under "/proc/xen".
845 proc_mkdir("xen", NULL);
851 xenbus_backend_bus_unregister();
854 bus_unregister(&xenbus_frontend.bus);
860 postcore_initcall(xenbus_probe_init);
862 MODULE_LICENSE("GPL");
864 static int is_device_connecting(struct device *dev, void *data)
866 struct xenbus_device *xendev = to_xenbus_device(dev);
867 struct device_driver *drv = data;
868 struct xenbus_driver *xendrv;
871 * A device with no driver will never connect. We care only about
872 * devices which should currently be in the process of connecting.
877 /* Is this search limited to a particular driver? */
878 if (drv && (dev->driver != drv))
881 xendrv = to_xenbus_driver(dev->driver);
882 return (xendev->state < XenbusStateConnected ||
883 (xendev->state == XenbusStateConnected &&
884 xendrv->is_ready && !xendrv->is_ready(xendev)));
887 static int exists_connecting_device(struct device_driver *drv)
889 return bus_for_each_dev(&xenbus_frontend.bus, NULL, drv,
890 is_device_connecting);
893 static int print_device_status(struct device *dev, void *data)
895 struct xenbus_device *xendev = to_xenbus_device(dev);
896 struct device_driver *drv = data;
898 /* Is this operation limited to a particular driver? */
899 if (drv && (dev->driver != drv))
903 /* Information only: is this too noisy? */
904 printk(KERN_INFO "XENBUS: Device with no driver: %s\n",
906 } else if (xendev->state < XenbusStateConnected) {
907 enum xenbus_state rstate = XenbusStateUnknown;
908 if (xendev->otherend)
909 rstate = xenbus_read_driver_state(xendev->otherend);
910 printk(KERN_WARNING "XENBUS: Timeout connecting "
911 "to device: %s (local state %d, remote state %d)\n",
912 xendev->nodename, xendev->state, rstate);
918 /* We only wait for device setup after most initcalls have run. */
919 static int ready_to_wait_for_devices;
922 * On a 5-minute timeout, wait for all devices currently configured. We need
923 * to do this to guarantee that the filesystems and / or network devices
924 * needed for boot are available, before we can allow the boot to proceed.
926 * This needs to be on a late_initcall, to happen after the frontend device
927 * drivers have been initialised, but before the root fs is mounted.
929 * A possible improvement here would be to have the tools add a per-device
930 * flag to the store entry, indicating whether it is needed at boot time.
931 * This would allow people who knew what they were doing to accelerate their
932 * boot slightly, but of course needs tools or manual intervention to set up
933 * those flags correctly.
935 static void wait_for_devices(struct xenbus_driver *xendrv)
937 unsigned long start = jiffies;
938 struct device_driver *drv = xendrv ? &xendrv->driver : NULL;
939 unsigned int seconds_waited = 0;
941 if (!ready_to_wait_for_devices || !xen_domain())
944 while (exists_connecting_device(drv)) {
945 if (time_after(jiffies, start + (seconds_waited+5)*HZ)) {
947 printk(KERN_WARNING "XENBUS: Waiting for "
948 "devices to initialise: ");
950 printk("%us...", 300 - seconds_waited);
951 if (seconds_waited == 300)
955 schedule_timeout_interruptible(HZ/10);
961 bus_for_each_dev(&xenbus_frontend.bus, NULL, drv,
962 print_device_status);
966 static int __init boot_wait_for_devices(void)
968 ready_to_wait_for_devices = 1;
969 wait_for_devices(NULL);
973 late_initcall(boot_wait_for_devices);