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_GPL(xen_store_evtchn);
68 struct xenstore_domain_interface *xen_store_interface;
69 EXPORT_SYMBOL_GPL(xen_store_interface);
71 static unsigned long xen_store_mfn;
73 static BLOCKING_NOTIFIER_HEAD(xenstore_chain);
75 /* If something in array of ids matches this device, return it. */
76 static const struct xenbus_device_id *
77 match_device(const struct xenbus_device_id *arr, struct xenbus_device *dev)
79 for (; *arr->devicetype != '\0'; arr++) {
80 if (!strcmp(arr->devicetype, dev->devicetype))
86 int xenbus_match(struct device *_dev, struct device_driver *_drv)
88 struct xenbus_driver *drv = to_xenbus_driver(_drv);
93 return match_device(drv->ids, to_xenbus_device(_dev)) != NULL;
95 EXPORT_SYMBOL_GPL(xenbus_match);
98 static void free_otherend_details(struct xenbus_device *dev)
100 kfree(dev->otherend);
101 dev->otherend = NULL;
105 static void free_otherend_watch(struct xenbus_device *dev)
107 if (dev->otherend_watch.node) {
108 unregister_xenbus_watch(&dev->otherend_watch);
109 kfree(dev->otherend_watch.node);
110 dev->otherend_watch.node = NULL;
115 static int talk_to_otherend(struct xenbus_device *dev)
117 struct xenbus_driver *drv = to_xenbus_driver(dev->dev.driver);
119 free_otherend_watch(dev);
120 free_otherend_details(dev);
122 return drv->read_otherend_details(dev);
127 static int watch_otherend(struct xenbus_device *dev)
129 struct xen_bus_type *bus = container_of(dev->dev.bus, struct xen_bus_type, bus);
131 return xenbus_watch_pathfmt(dev, &dev->otherend_watch, bus->otherend_changed,
132 "%s/%s", dev->otherend, "state");
136 int xenbus_read_otherend_details(struct xenbus_device *xendev,
137 char *id_node, char *path_node)
139 int err = xenbus_gather(XBT_NIL, xendev->nodename,
140 id_node, "%i", &xendev->otherend_id,
141 path_node, NULL, &xendev->otherend,
144 xenbus_dev_fatal(xendev, err,
145 "reading other end details from %s",
149 if (strlen(xendev->otherend) == 0 ||
150 !xenbus_exists(XBT_NIL, xendev->otherend, "")) {
151 xenbus_dev_fatal(xendev, -ENOENT,
152 "unable to read other end from %s. "
153 "missing or inaccessible.",
155 free_otherend_details(xendev);
161 EXPORT_SYMBOL_GPL(xenbus_read_otherend_details);
163 void xenbus_otherend_changed(struct xenbus_watch *watch,
164 const char **vec, unsigned int len,
165 int ignore_on_shutdown)
167 struct xenbus_device *dev =
168 container_of(watch, struct xenbus_device, otherend_watch);
169 struct xenbus_driver *drv = to_xenbus_driver(dev->dev.driver);
170 enum xenbus_state state;
172 /* Protect us against watches firing on old details when the otherend
173 details change, say immediately after a resume. */
174 if (!dev->otherend ||
175 strncmp(dev->otherend, vec[XS_WATCH_PATH],
176 strlen(dev->otherend))) {
177 dev_dbg(&dev->dev, "Ignoring watch at %s\n",
182 state = xenbus_read_driver_state(dev->otherend);
184 dev_dbg(&dev->dev, "state is %d, (%s), %s, %s\n",
185 state, xenbus_strstate(state), dev->otherend_watch.node,
189 * Ignore xenbus transitions during shutdown. This prevents us doing
190 * work that can fail e.g., when the rootfs is gone.
192 if (system_state > SYSTEM_RUNNING) {
193 if (ignore_on_shutdown && (state == XenbusStateClosing))
194 xenbus_frontend_closed(dev);
198 if (drv->otherend_changed)
199 drv->otherend_changed(dev, state);
201 EXPORT_SYMBOL_GPL(xenbus_otherend_changed);
203 int xenbus_dev_probe(struct device *_dev)
205 struct xenbus_device *dev = to_xenbus_device(_dev);
206 struct xenbus_driver *drv = to_xenbus_driver(_dev->driver);
207 const struct xenbus_device_id *id;
210 DPRINTK("%s", dev->nodename);
217 id = match_device(drv->ids, dev);
223 err = talk_to_otherend(dev);
225 dev_warn(&dev->dev, "talk_to_otherend on %s failed.\n",
230 err = drv->probe(dev, id);
234 err = watch_otherend(dev);
236 dev_warn(&dev->dev, "watch_otherend on %s failed.\n",
243 xenbus_dev_error(dev, err, "xenbus_dev_probe on %s", dev->nodename);
244 xenbus_switch_state(dev, XenbusStateClosed);
247 EXPORT_SYMBOL_GPL(xenbus_dev_probe);
249 int xenbus_dev_remove(struct device *_dev)
251 struct xenbus_device *dev = to_xenbus_device(_dev);
252 struct xenbus_driver *drv = to_xenbus_driver(_dev->driver);
254 DPRINTK("%s", dev->nodename);
256 free_otherend_watch(dev);
257 free_otherend_details(dev);
262 xenbus_switch_state(dev, XenbusStateClosed);
265 EXPORT_SYMBOL_GPL(xenbus_dev_remove);
267 void xenbus_dev_shutdown(struct device *_dev)
269 struct xenbus_device *dev = to_xenbus_device(_dev);
270 unsigned long timeout = 5*HZ;
272 DPRINTK("%s", dev->nodename);
274 get_device(&dev->dev);
275 if (dev->state != XenbusStateConnected) {
276 printk(KERN_INFO "%s: %s: %s != Connected, skipping\n", __func__,
277 dev->nodename, xenbus_strstate(dev->state));
280 xenbus_switch_state(dev, XenbusStateClosing);
281 timeout = wait_for_completion_timeout(&dev->down, timeout);
283 printk(KERN_INFO "%s: %s timeout closing device\n",
284 __func__, dev->nodename);
286 put_device(&dev->dev);
288 EXPORT_SYMBOL_GPL(xenbus_dev_shutdown);
290 int xenbus_register_driver_common(struct xenbus_driver *drv,
291 struct xen_bus_type *bus,
292 struct module *owner,
293 const char *mod_name)
295 drv->driver.name = drv->name;
296 drv->driver.bus = &bus->bus;
297 drv->driver.owner = owner;
298 drv->driver.mod_name = mod_name;
300 return driver_register(&drv->driver);
302 EXPORT_SYMBOL_GPL(xenbus_register_driver_common);
304 void xenbus_unregister_driver(struct xenbus_driver *drv)
306 driver_unregister(&drv->driver);
308 EXPORT_SYMBOL_GPL(xenbus_unregister_driver);
312 struct xenbus_device *dev;
313 const char *nodename;
316 static int cmp_dev(struct device *dev, void *data)
318 struct xenbus_device *xendev = to_xenbus_device(dev);
319 struct xb_find_info *info = data;
321 if (!strcmp(xendev->nodename, info->nodename)) {
329 struct xenbus_device *xenbus_device_find(const char *nodename,
330 struct bus_type *bus)
332 struct xb_find_info info = { .dev = NULL, .nodename = nodename };
334 bus_for_each_dev(bus, NULL, &info, cmp_dev);
338 static int cleanup_dev(struct device *dev, void *data)
340 struct xenbus_device *xendev = to_xenbus_device(dev);
341 struct xb_find_info *info = data;
342 int len = strlen(info->nodename);
344 DPRINTK("%s", info->nodename);
346 /* Match the info->nodename path, or any subdirectory of that path. */
347 if (strncmp(xendev->nodename, info->nodename, len))
350 /* If the node name is longer, ensure it really is a subdirectory. */
351 if ((strlen(xendev->nodename) > len) && (xendev->nodename[len] != '/'))
359 static void xenbus_cleanup_devices(const char *path, struct bus_type *bus)
361 struct xb_find_info info = { .nodename = path };
365 bus_for_each_dev(bus, NULL, &info, cleanup_dev);
367 device_unregister(&info.dev->dev);
368 put_device(&info.dev->dev);
373 static void xenbus_dev_release(struct device *dev)
376 kfree(to_xenbus_device(dev));
379 static ssize_t xendev_show_nodename(struct device *dev,
380 struct device_attribute *attr, char *buf)
382 return sprintf(buf, "%s\n", to_xenbus_device(dev)->nodename);
384 static DEVICE_ATTR(nodename, S_IRUSR | S_IRGRP | S_IROTH, xendev_show_nodename, NULL);
386 static ssize_t xendev_show_devtype(struct device *dev,
387 struct device_attribute *attr, char *buf)
389 return sprintf(buf, "%s\n", to_xenbus_device(dev)->devicetype);
391 static DEVICE_ATTR(devtype, S_IRUSR | S_IRGRP | S_IROTH, xendev_show_devtype, NULL);
393 static ssize_t xendev_show_modalias(struct device *dev,
394 struct device_attribute *attr, char *buf)
396 return sprintf(buf, "xen:%s\n", to_xenbus_device(dev)->devicetype);
398 static DEVICE_ATTR(modalias, S_IRUSR | S_IRGRP | S_IROTH, xendev_show_modalias, NULL);
400 int xenbus_probe_node(struct xen_bus_type *bus,
402 const char *nodename)
404 char devname[XEN_BUS_ID_SIZE];
406 struct xenbus_device *xendev;
410 enum xenbus_state state = xenbus_read_driver_state(nodename);
412 if (state != XenbusStateInitialising) {
413 /* Device is not new, so ignore it. This can happen if a
414 device is going away after switching to Closed. */
418 stringlen = strlen(nodename) + 1 + strlen(type) + 1;
419 xendev = kzalloc(sizeof(*xendev) + stringlen, GFP_KERNEL);
423 xendev->state = XenbusStateInitialising;
425 /* Copy the strings into the extra space. */
427 tmpstring = (char *)(xendev + 1);
428 strcpy(tmpstring, nodename);
429 xendev->nodename = tmpstring;
431 tmpstring += strlen(tmpstring) + 1;
432 strcpy(tmpstring, type);
433 xendev->devicetype = tmpstring;
434 init_completion(&xendev->down);
436 xendev->dev.bus = &bus->bus;
437 xendev->dev.release = xenbus_dev_release;
439 err = bus->get_bus_id(devname, xendev->nodename);
443 dev_set_name(&xendev->dev, devname);
445 /* Register with generic device framework. */
446 err = device_register(&xendev->dev);
450 err = device_create_file(&xendev->dev, &dev_attr_nodename);
452 goto fail_unregister;
454 err = device_create_file(&xendev->dev, &dev_attr_devtype);
456 goto fail_remove_nodename;
458 err = device_create_file(&xendev->dev, &dev_attr_modalias);
460 goto fail_remove_devtype;
464 device_remove_file(&xendev->dev, &dev_attr_devtype);
465 fail_remove_nodename:
466 device_remove_file(&xendev->dev, &dev_attr_nodename);
468 device_unregister(&xendev->dev);
473 EXPORT_SYMBOL_GPL(xenbus_probe_node);
475 static int xenbus_probe_device_type(struct xen_bus_type *bus, const char *type)
479 unsigned int dir_n = 0;
482 printk(KERN_CRIT "%s type %s\n", __func__, type);
484 dir = xenbus_directory(XBT_NIL, bus->root, type, &dir_n);
486 printk(KERN_CRIT "%s failed xenbus_directory\n", __func__);
490 for (i = 0; i < dir_n; i++) {
491 printk(KERN_CRIT "%s %d/%d %s\n", __func__, i+1,dir_n, dir[i]);
492 err = bus->probe(bus, type, dir[i]);
494 printk(KERN_CRIT "%s failed\n", __func__);
498 printk("%s done\n", __func__);
503 int xenbus_probe_devices(struct xen_bus_type *bus)
507 unsigned int i, dir_n;
509 printk(KERN_CRIT "%s %s\n", __func__, bus->root);
511 dir = xenbus_directory(XBT_NIL, bus->root, "", &dir_n);
513 printk(KERN_CRIT "%s failed xenbus_directory\n", __func__);
517 for (i = 0; i < dir_n; i++) {
518 printk(KERN_CRIT "%s %d/%d %s\n", __func__, i+1,dir_n, dir[i]);
519 err = xenbus_probe_device_type(bus, dir[i]);
521 printk(KERN_CRIT "%s failed\n", __func__);
525 printk("%s done\n", __func__);
529 EXPORT_SYMBOL_GPL(xenbus_probe_devices);
531 static unsigned int char_count(const char *str, char c)
533 unsigned int i, ret = 0;
535 for (i = 0; str[i]; i++)
541 static int strsep_len(const char *str, char c, unsigned int len)
545 for (i = 0; str[i]; i++)
551 return (len == 0) ? i : -ERANGE;
554 void xenbus_dev_changed(const char *node, struct xen_bus_type *bus)
557 struct xenbus_device *dev;
558 char type[XEN_BUS_ID_SIZE];
559 const char *p, *root;
561 if (char_count(node, '/') < 2)
564 exists = xenbus_exists(XBT_NIL, node, "");
566 xenbus_cleanup_devices(node, &bus->bus);
570 /* backend/<type>/... or device/<type>/... */
571 p = strchr(node, '/') + 1;
572 snprintf(type, XEN_BUS_ID_SIZE, "%.*s", (int)strcspn(p, "/"), p);
573 type[XEN_BUS_ID_SIZE-1] = '\0';
575 rootlen = strsep_len(node, '/', bus->levels);
578 root = kasprintf(GFP_KERNEL, "%.*s", rootlen, node);
582 dev = xenbus_device_find(root, &bus->bus);
584 xenbus_probe_node(bus, type, root);
586 put_device(&dev->dev);
590 EXPORT_SYMBOL_GPL(xenbus_dev_changed);
592 int xenbus_dev_suspend(struct device *dev, pm_message_t state)
595 struct xenbus_driver *drv;
596 struct xenbus_device *xdev = container_of(dev, struct xenbus_device, dev);
598 DPRINTK("%s", xdev->nodename);
600 if (dev->driver == NULL)
602 drv = to_xenbus_driver(dev->driver);
604 err = drv->suspend(xdev, state);
607 "xenbus: suspend %s failed: %i\n", dev_name(dev), err);
610 EXPORT_SYMBOL_GPL(xenbus_dev_suspend);
612 int xenbus_dev_resume(struct device *dev)
615 struct xenbus_driver *drv;
616 struct xenbus_device *xdev = container_of(dev, struct xenbus_device, dev);
618 DPRINTK("%s", xdev->nodename);
620 if (dev->driver == NULL)
622 drv = to_xenbus_driver(dev->driver);
623 err = talk_to_otherend(xdev);
626 "xenbus: resume (talk_to_otherend) %s failed: %i\n",
631 xdev->state = XenbusStateInitialising;
634 err = drv->resume(xdev);
637 "xenbus: resume %s failed: %i\n",
643 err = watch_otherend(xdev);
646 "xenbus_probe: resume (watch_otherend) %s failed: "
647 "%d.\n", dev_name(dev), err);
653 EXPORT_SYMBOL_GPL(xenbus_dev_resume);
655 /* A flag to determine if xenstored is 'ready' (i.e. has started) */
656 int xenstored_ready = 0;
659 int register_xenstore_notifier(struct notifier_block *nb)
663 if (xenstored_ready > 0)
664 ret = nb->notifier_call(nb, 0, NULL);
666 blocking_notifier_chain_register(&xenstore_chain, nb);
670 EXPORT_SYMBOL_GPL(register_xenstore_notifier);
672 void unregister_xenstore_notifier(struct notifier_block *nb)
674 blocking_notifier_chain_unregister(&xenstore_chain, nb);
676 EXPORT_SYMBOL_GPL(unregister_xenstore_notifier);
678 void xenbus_probe(struct work_struct *unused)
682 printk(KERN_CRIT "xenbus_probe wake_waiting\n");
684 /* Notify others that xenstore is up */
685 blocking_notifier_call_chain(&xenstore_chain, 0, NULL);
687 EXPORT_SYMBOL_GPL(xenbus_probe);
689 static int __init xenbus_probe_initcall(void)
694 if (xen_initial_domain() || xen_hvm_domain())
701 device_initcall(xenbus_probe_initcall);
703 static int __init xenbus_init(void)
706 unsigned long page = 0;
715 * Domain0 doesn't have a store_evtchn or store_mfn yet.
717 if (xen_initial_domain()) {
718 struct evtchn_alloc_unbound alloc_unbound;
720 /* Allocate Xenstore page */
721 page = get_zeroed_page(GFP_KERNEL);
725 xen_store_mfn = xen_start_info->store_mfn =
726 pfn_to_mfn(virt_to_phys((void *)page) >>
729 /* Next allocate a local port which xenstored can bind to */
730 alloc_unbound.dom = DOMID_SELF;
731 alloc_unbound.remote_dom = 0;
733 err = HYPERVISOR_event_channel_op(EVTCHNOP_alloc_unbound,
739 xen_store_evtchn = xen_start_info->store_evtchn =
742 xen_store_interface = mfn_to_virt(xen_store_mfn);
744 if (xen_hvm_domain()) {
746 err = hvm_get_parameter(HVM_PARAM_STORE_EVTCHN, &v);
749 xen_store_evtchn = (int)v;
750 err = hvm_get_parameter(HVM_PARAM_STORE_PFN, &v);
753 xen_store_mfn = (unsigned long)v;
754 xen_store_interface = ioremap(xen_store_mfn << PAGE_SHIFT, PAGE_SIZE);
756 xen_store_evtchn = xen_start_info->store_evtchn;
757 xen_store_mfn = xen_start_info->store_mfn;
758 xen_store_interface = mfn_to_virt(xen_store_mfn);
763 /* Initialize the interface to xenstore. */
767 "XENBUS: Error initializing xenstore comms: %i\n", err);
771 #ifdef CONFIG_XEN_COMPAT_XENFS
773 * Create xenfs mountpoint in /proc for compatibility with
774 * utilities that expect to find "xenbus" under "/proc/xen".
776 proc_mkdir("xen", NULL);
779 printk(KERN_CRIT "%s ok\n", __func__);
789 postcore_initcall(xenbus_init);
791 MODULE_LICENSE("GPL");