1 /******************************************************************************
2 * Talks to Xen Store to figure out what devices we have.
3 *
4 * Copyright (C) 2009, 2010 Spectra Logic Corporation
5 * Copyright (C) 2008 Doug Rabson
6 * Copyright (C) 2005 Rusty Russell, IBM Corporation
7 * Copyright (C) 2005 Mike Wray, Hewlett-Packard
8 * Copyright (C) 2005 XenSource Ltd
9 *
10 * This file may be distributed separately from the Linux kernel, or
11 * incorporated into other software packages, subject to the following license:
12 *
13 * Permission is hereby granted, free of charge, to any person obtaining a copy
14 * of this source file (the "Software"), to deal in the Software without
15 * restriction, including without limitation the rights to use, copy, modify,
16 * merge, publish, distribute, sublicense, and/or sell copies of the Software,
17 * and to permit persons to whom the Software is furnished to do so, subject to
18 * the following conditions:
19 *
20 * The above copyright notice and this permission notice shall be included in
21 * all copies or substantial portions of the Software.
22 *
23 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
24 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
25 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
26 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
27 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
28 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
29 * IN THE SOFTWARE.
30 */
31
32 /**
33 * \file xenbusb_front.c
34 *
35 * XenBus management of the NewBus bus containing the frontend instances of
36 * Xen split devices.
37 */
38
39 #include <sys/param.h>
40 #include <sys/bus.h>
41 #include <sys/kernel.h>
42 #include <sys/lock.h>
43 #include <sys/malloc.h>
44 #include <sys/module.h>
45 #include <sys/sbuf.h>
46 #include <sys/stdarg.h>
47 #include <sys/sysctl.h>
48 #include <sys/syslog.h>
49 #include <sys/systm.h>
50 #include <sys/sx.h>
51 #include <sys/taskqueue.h>
52
53 #include <xen/xen-os.h>
54 #include <xen/gnttab.h>
55 #include <xen/xenbus/xenbusvar.h>
56 #include <xen/xenbus/xenbusb.h>
57
58 /*------------------ Private Device Attachment Functions --------------------*/
59 /**
60 * \brief Probe for the existence of the XenBus front bus.
61 *
62 * \param dev NewBus device_t for this XenBus front bus instance.
63 *
64 * \return Always returns 0 indicating success.
65 */
66 static int
xenbusb_front_probe(device_t dev)67 xenbusb_front_probe(device_t dev)
68 {
69 device_set_desc(dev, "Xen Frontend Devices");
70
71 return (0);
72 }
73
74 /**
75 * \brief Attach the XenBus front bus.
76 *
77 * \param dev NewBus device_t for this XenBus front bus instance.
78 *
79 * \return On success, 0. Otherwise an errno value indicating the
80 * type of failure.
81 */
82 static int
xenbusb_front_attach(device_t dev)83 xenbusb_front_attach(device_t dev)
84 {
85 return (xenbusb_attach(dev, "device", /*id_components*/1));
86 }
87
88 /**
89 * \brief Enumerate all devices of the given type on this bus.
90 *
91 * \param dev NewBus device_t for this XenBus front bus instance.
92 * \param type String indicating the device sub-tree (e.g. "vfb", "vif")
93 * to enumerate.
94 *
95 * \return On success, 0. Otherwise an errno value indicating the
96 * type of failure.
97 *
98 * Devices that are found are entered into the NewBus hierarchy via
99 * xenbusb_add_device(). xenbusb_add_device() ignores duplicate detects
100 * and ignores duplicate devices, so it can be called unconditionally
101 * for any device found in the XenStore.
102 */
103 static int
xenbusb_front_enumerate_type(device_t dev,const char * type)104 xenbusb_front_enumerate_type(device_t dev, const char *type)
105 {
106 struct xenbusb_softc *xbs;
107 const char **dir;
108 unsigned int i, count;
109 int error;
110
111 xbs = device_get_softc(dev);
112 error = xs_directory(XST_NIL, xbs->xbs_node, type, &count, &dir);
113 if (error)
114 return (error);
115 for (i = 0; i < count; i++)
116 xenbusb_add_device(dev, type, dir[i]);
117
118 free(dir, M_XENSTORE);
119
120 return (0);
121 }
122
123 /**
124 * \brief Determine and store the XenStore path for the other end of
125 * a split device whose local end is represented by ivars.
126 *
127 * If successful, the xd_otherend_path field of the child's instance
128 * variables will be updated.
129 *
130 * \param dev NewBus device_t for this XenBus front bus instance.
131 * \param ivars Instance variables from the XenBus child device for
132 * which to perform this function.
133 *
134 * \return On success, 0. Otherwise an errno value indicating the
135 * type of failure.
136 */
137 static int
xenbusb_front_get_otherend_node(device_t dev,struct xenbus_device_ivars * ivars)138 xenbusb_front_get_otherend_node(device_t dev, struct xenbus_device_ivars *ivars)
139 {
140 char *otherend_path;
141 int error;
142
143 if (ivars->xd_otherend_path != NULL) {
144 free(ivars->xd_otherend_path, M_XENBUS);
145 ivars->xd_otherend_path = NULL;
146 }
147
148 error = xs_gather(XST_NIL, ivars->xd_node,
149 "backend-id", "%i", &ivars->xd_otherend_id,
150 "backend", NULL, &otherend_path,
151 NULL);
152
153 if (error == 0) {
154 ivars->xd_otherend_path = strdup(otherend_path, M_XENBUS);
155 ivars->xd_otherend_path_len = strlen(otherend_path);
156 free(otherend_path, M_XENSTORE);
157 }
158 return (error);
159 }
160
161 /*-------------------- Private Device Attachment Data -----------------------*/
162 static device_method_t xenbusb_front_methods[] = {
163 /* Device interface */
164 DEVMETHOD(device_identify, xenbusb_identify),
165 DEVMETHOD(device_probe, xenbusb_front_probe),
166 DEVMETHOD(device_attach, xenbusb_front_attach),
167 DEVMETHOD(device_detach, bus_generic_detach),
168 DEVMETHOD(device_shutdown, bus_generic_shutdown),
169 DEVMETHOD(device_suspend, bus_generic_suspend),
170 DEVMETHOD(device_resume, xenbusb_resume),
171
172 /* Bus Interface */
173 DEVMETHOD(bus_print_child, xenbusb_print_child),
174 DEVMETHOD(bus_read_ivar, xenbusb_read_ivar),
175 DEVMETHOD(bus_write_ivar, xenbusb_write_ivar),
176 DEVMETHOD(bus_alloc_resource, bus_generic_alloc_resource),
177 DEVMETHOD(bus_release_resource, bus_generic_release_resource),
178 DEVMETHOD(bus_activate_resource, bus_generic_activate_resource),
179 DEVMETHOD(bus_deactivate_resource, bus_generic_deactivate_resource),
180
181 /* XenBus Bus Interface */
182 DEVMETHOD(xenbusb_enumerate_type, xenbusb_front_enumerate_type),
183 DEVMETHOD(xenbusb_get_otherend_node, xenbusb_front_get_otherend_node),
184
185 DEVMETHOD_END
186 };
187
188 DEFINE_CLASS_0(xenbusb_front, xenbusb_front_driver, xenbusb_front_methods,
189 sizeof(struct xenbusb_softc));
190
191 DRIVER_MODULE(xenbusb_front, xenstore, xenbusb_front_driver, 0, 0);
192