1 /******************************************************************************
2 * Talks to Xen Store to figure out what devices we have (backend half).
4 * Copyright (C) 2005 Rusty Russell, IBM Corporation
5 * Copyright (C) 2005 Mike Wray, Hewlett-Packard
6 * Copyright (C) 2005, 2006 XenSource Ltd
7 * Copyright (C) 2007 Solarflare Communications, Inc.
9 * This program is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU General Public License version 2
11 * as published by the Free Software Foundation; or, when distributed
12 * separately from the Linux kernel or incorporated into other
13 * software packages, subject to the following license:
15 * Permission is hereby granted, free of charge, to any person obtaining a copy
16 * of this source file (the "Software"), to deal in the Software without
17 * restriction, including without limitation the rights to use, copy, modify,
18 * merge, publish, distribute, sublicense, and/or sell copies of the Software,
19 * and to permit persons to whom the Software is furnished to do so, subject to
20 * the following conditions:
22 * The above copyright notice and this permission notice shall be included in
23 * all copies or substantial portions of the Software.
25 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
26 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
27 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
28 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
29 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
30 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
34 #define DPRINTK(fmt, args...) \
35 pr_debug("xenbus_probe (%s:%d) " fmt ".\n", \
36 __func__, __LINE__, ##args)
38 #include <linux/kernel.h>
39 #include <linux/version.h>
40 #include <linux/err.h>
41 #include <linux/string.h>
42 #include <linux/ctype.h>
43 #include <linux/fcntl.h>
45 #include <linux/slab.h>
46 #include <linux/notifier.h>
47 #include <linux/export.h>
50 #include <asm/pgtable.h>
52 #include <asm/xen/hypervisor.h>
54 #include <asm/hypervisor.h>
55 #include <xen/xenbus.h>
57 #include <xen/xen_proc.h>
58 #include <xen/evtchn.h>
60 #include <xen/features.h>
62 #include "xenbus_comms.h"
63 #include "xenbus_probe.h"
65 #ifdef HAVE_XEN_PLATFORM_COMPAT_H
66 #include <xen/platform-compat.h>
69 /* backend/<type>/<fe-uuid>/<id> => <type>-<fe-domid>-<id> */
70 static int backend_bus_id(char bus_id[XEN_BUS_ID_SIZE], const char *nodename)
73 const char *devid, *type, *frontend;
76 type = strchr(nodename, '/');
80 typelen = strcspn(type, "/");
81 if (!typelen || type[typelen] != '/')
84 devid = strrchr(nodename, '/') + 1;
86 err = xenbus_gather(XBT_NIL, nodename, "frontend-id", "%i", &domid,
87 "frontend", NULL, &frontend,
91 if (strlen(frontend) == 0)
93 if (!err && !xenbus_exists(XBT_NIL, frontend, ""))
100 if (snprintf(bus_id, XEN_BUS_ID_SIZE, "%.*s-%i-%s",
101 typelen, type, domid, devid) >= XEN_BUS_ID_SIZE)
106 static int xenbus_uevent_backend(struct device *dev,
107 struct kobj_uevent_env *env)
109 struct xenbus_device *xdev;
110 struct xenbus_driver *drv;
111 struct xen_bus_type *bus;
118 xdev = to_xenbus_device(dev);
119 bus = container_of(xdev->dev.bus, struct xen_bus_type, bus);
121 if (add_uevent_var(env, "MODALIAS=xen-backend:%s", xdev->devicetype))
124 /* stuff we want to pass to /sbin/hotplug */
125 if (add_uevent_var(env, "XENBUS_TYPE=%s", xdev->devicetype))
128 if (add_uevent_var(env, "XENBUS_PATH=%s", xdev->nodename))
131 if (add_uevent_var(env, "XENBUS_BASE_PATH=%s", bus->root))
135 drv = to_xenbus_driver(dev->driver);
136 if (drv && drv->uevent)
137 return drv->uevent(xdev, env);
143 /* backend/<typename>/<frontend-uuid>/<name> */
144 static int xenbus_probe_backend_unit(struct xen_bus_type *bus,
152 nodename = kasprintf(GFP_KERNEL, "%s/%s", dir, name);
156 DPRINTK("%s\n", nodename);
158 err = xenbus_probe_node(bus, type, nodename);
163 /* backend/<typename>/<frontend-domid> */
164 static int xenbus_probe_backend(struct xen_bus_type *bus, const char *type,
170 unsigned int i, dir_n = 0;
174 nodename = kasprintf(GFP_KERNEL, "%s/%s/%s", bus->root, type, domid);
178 dir = xenbus_directory(XBT_NIL, nodename, "", &dir_n);
184 for (i = 0; i < dir_n; i++) {
185 err = xenbus_probe_backend_unit(bus, nodename, type, dir[i]);
195 static void frontend_changed(struct xenbus_watch *watch,
196 const char **vec, unsigned int len)
198 xenbus_otherend_changed(watch, vec, len, 0);
202 static struct xen_bus_type xenbus_backend = {
204 .levels = 3, /* backend/type/<frontend>/<id> */
205 .get_bus_id = backend_bus_id,
206 .probe = xenbus_probe_backend,
208 .otherend_changed = frontend_changed,
211 .init_name = "xen-backend",
216 .name = "xen-backend",
217 .match = xenbus_match,
218 .uevent = xenbus_uevent_backend,
219 .probe = xenbus_dev_probe,
220 .remove = xenbus_dev_remove,
222 .shutdown = xenbus_dev_shutdown,
224 .dev_attrs = xenbus_dev_attrs,
228 static void backend_changed(struct xenbus_watch *watch,
229 const char **vec, unsigned int len)
233 xenbus_dev_changed(vec[XS_WATCH_PATH], &xenbus_backend);
236 static struct xenbus_watch be_watch = {
238 .callback = backend_changed,
241 static int read_frontend_details(struct xenbus_device *xendev)
243 return xenbus_read_otherend_details(xendev, "frontend-id", "frontend");
247 int xenbus_dev_is_online(struct xenbus_device *dev)
251 rc = xenbus_scanf(XBT_NIL, dev->nodename, "online", "%d", &val);
253 val = 0; /* no online node present */
257 EXPORT_SYMBOL_GPL(xenbus_dev_is_online);
260 int xenbus_register_backend(struct xenbus_driver *drv)
262 drv->read_otherend_details = read_frontend_details;
264 return xenbus_register_driver_common(drv, &xenbus_backend);
266 EXPORT_SYMBOL_GPL(xenbus_register_backend);
268 #if defined(CONFIG_XEN) && defined(CONFIG_PM_SLEEP)
269 void xenbus_backend_suspend(int (*fn)(struct device *, void *))
272 if (!xenbus_backend.error)
273 bus_for_each_dev(&xenbus_backend.bus, NULL, NULL, fn);
276 void xenbus_backend_resume(int (*fn)(struct device *, void *))
279 if (!xenbus_backend.error)
280 bus_for_each_dev(&xenbus_backend.bus, NULL, NULL, fn);
285 static int backend_probe_and_watch(struct notifier_block *notifier,
289 void xenbus_backend_probe_and_watch(void)
292 /* Enumerate devices in xenstore and watch for changes. */
293 xenbus_probe_devices(&xenbus_backend);
294 register_xenbus_watch(&be_watch);
303 static int __init xenbus_probe_backend_init(void)
305 static struct notifier_block xenstore_notifier = {
306 .notifier_call = backend_probe_and_watch
312 /* Register ourselves with the kernel bus subsystem */
313 err = bus_register(&xenbus_backend.bus);
317 register_xenstore_notifier(&xenstore_notifier);
321 subsys_initcall(xenbus_probe_backend_init);
325 void __init xenbus_backend_bus_register(void)
327 xenbus_backend.error = bus_register(&xenbus_backend.bus);
328 if (xenbus_backend.error)
329 pr_warning("XENBUS: Error registering backend bus: %i\n",
330 xenbus_backend.error);
333 void __init xenbus_backend_device_register(void)
335 if (xenbus_backend.error)
338 xenbus_backend.error = device_register(&xenbus_backend.dev);
339 if (xenbus_backend.error) {
340 bus_unregister(&xenbus_backend.bus);
341 pr_warning("XENBUS: Error registering backend device: %i\n",
342 xenbus_backend.error);
346 int xenbus_for_each_backend(void *arg, int (*fn)(struct device *, void *))
348 return bus_for_each_dev(&xenbus_backend.bus, NULL, arg, fn);
350 EXPORT_SYMBOL_GPL(xenbus_for_each_backend);