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/sysctl.h>
47 #include <sys/syslog.h>
48 #include <sys/systm.h>
49 #include <sys/sx.h>
50 #include <sys/taskqueue.h>
51
52 #include <machine/stdarg.h>
53
54 #include <xen/xen-os.h>
55 #include <xen/gnttab.h>
56 #include <xen/xenbus/xenbusvar.h>
57 #include <xen/xenbus/xenbusb.h>
58
59 /*------------------ Private Device Attachment Functions --------------------*/
60 /**
61 * \brief Probe for the existence of the XenBus front bus.
62 *
63 * \param dev NewBus device_t for this XenBus front bus instance.
64 *
65 * \return Always returns 0 indicating success.
66 */
67 static int
xenbusb_front_probe(device_t dev)68 xenbusb_front_probe(device_t dev)
69 {
70 device_set_desc(dev, "Xen Frontend Devices");
71
72 return (0);
73 }
74
75 /**
76 * \brief Attach the XenBus front bus.
77 *
78 * \param dev NewBus device_t for this XenBus front bus instance.
79 *
80 * \return On success, 0. Otherwise an errno value indicating the
81 * type of failure.
82 */
83 static int
xenbusb_front_attach(device_t dev)84 xenbusb_front_attach(device_t dev)
85 {
86 return (xenbusb_attach(dev, "device", /*id_components*/1));
87 }
88
89 /**
90 * \brief Enumerate all devices of the given type on this bus.
91 *
92 * \param dev NewBus device_t for this XenBus front bus instance.
93 * \param type String indicating the device sub-tree (e.g. "vfb", "vif")
94 * to enumerate.
95 *
96 * \return On success, 0. Otherwise an errno value indicating the
97 * type of failure.
98 *
99 * Devices that are found are entered into the NewBus hierarchy via
100 * xenbusb_add_device(). xenbusb_add_device() ignores duplicate detects
101 * and ignores duplicate devices, so it can be called unconditionally
102 * for any device found in the XenStore.
103 */
104 static int
xenbusb_front_enumerate_type(device_t dev,const char * type)105 xenbusb_front_enumerate_type(device_t dev, const char *type)
106 {
107 struct xenbusb_softc *xbs;
108 const char **dir;
109 unsigned int i, count;
110 int error;
111
112 xbs = device_get_softc(dev);
113 error = xs_directory(XST_NIL, xbs->xbs_node, type, &count, &dir);
114 if (error)
115 return (error);
116 for (i = 0; i < count; i++)
117 xenbusb_add_device(dev, type, dir[i]);
118
119 free(dir, M_XENSTORE);
120
121 return (0);
122 }
123
124 /**
125 * \brief Determine and store the XenStore path for the other end of
126 * a split device whose local end is represented by ivars.
127 *
128 * If successful, the xd_otherend_path field of the child's instance
129 * variables will be updated.
130 *
131 * \param dev NewBus device_t for this XenBus front bus instance.
132 * \param ivars Instance variables from the XenBus child device for
133 * which to perform this function.
134 *
135 * \return On success, 0. Otherwise an errno value indicating the
136 * type of failure.
137 */
138 static int
xenbusb_front_get_otherend_node(device_t dev,struct xenbus_device_ivars * ivars)139 xenbusb_front_get_otherend_node(device_t dev, struct xenbus_device_ivars *ivars)
140 {
141 char *otherend_path;
142 int error;
143
144 if (ivars->xd_otherend_path != NULL) {
145 free(ivars->xd_otherend_path, M_XENBUS);
146 ivars->xd_otherend_path = NULL;
147 }
148
149 error = xs_gather(XST_NIL, ivars->xd_node,
150 "backend-id", "%i", &ivars->xd_otherend_id,
151 "backend", NULL, &otherend_path,
152 NULL);
153
154 if (error == 0) {
155 ivars->xd_otherend_path = strdup(otherend_path, M_XENBUS);
156 ivars->xd_otherend_path_len = strlen(otherend_path);
157 free(otherend_path, M_XENSTORE);
158 }
159 return (error);
160 }
161
162 /*-------------------- Private Device Attachment Data -----------------------*/
163 static device_method_t xenbusb_front_methods[] = {
164 /* Device interface */
165 DEVMETHOD(device_identify, xenbusb_identify),
166 DEVMETHOD(device_probe, xenbusb_front_probe),
167 DEVMETHOD(device_attach, xenbusb_front_attach),
168 DEVMETHOD(device_detach, bus_generic_detach),
169 DEVMETHOD(device_shutdown, bus_generic_shutdown),
170 DEVMETHOD(device_suspend, bus_generic_suspend),
171 DEVMETHOD(device_resume, xenbusb_resume),
172
173 /* Bus Interface */
174 DEVMETHOD(bus_print_child, xenbusb_print_child),
175 DEVMETHOD(bus_read_ivar, xenbusb_read_ivar),
176 DEVMETHOD(bus_write_ivar, xenbusb_write_ivar),
177 DEVMETHOD(bus_alloc_resource, bus_generic_alloc_resource),
178 DEVMETHOD(bus_release_resource, bus_generic_release_resource),
179 DEVMETHOD(bus_activate_resource, bus_generic_activate_resource),
180 DEVMETHOD(bus_deactivate_resource, bus_generic_deactivate_resource),
181
182 /* XenBus Bus Interface */
183 DEVMETHOD(xenbusb_enumerate_type, xenbusb_front_enumerate_type),
184 DEVMETHOD(xenbusb_get_otherend_node, xenbusb_front_get_otherend_node),
185
186 DEVMETHOD_END
187 };
188
189 DEFINE_CLASS_0(xenbusb_front, xenbusb_front_driver, xenbusb_front_methods,
190 sizeof(struct xenbusb_softc));
191
192 DRIVER_MODULE(xenbusb_front, xenstore, xenbusb_front_driver, 0, 0);
193