xref: /freebsd/sys/xen/xenbus/xenbusb_front.c (revision f7c32ed617858bcd22f8d1b03199099d50125721)
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 #include <sys/cdefs.h>
39 __FBSDID("$FreeBSD$");
40 
41 #include <sys/param.h>
42 #include <sys/bus.h>
43 #include <sys/kernel.h>
44 #include <sys/lock.h>
45 #include <sys/malloc.h>
46 #include <sys/module.h>
47 #include <sys/sbuf.h>
48 #include <sys/sysctl.h>
49 #include <sys/syslog.h>
50 #include <sys/systm.h>
51 #include <sys/sx.h>
52 #include <sys/taskqueue.h>
53 
54 #include <machine/stdarg.h>
55 
56 #include <xen/xen-os.h>
57 #include <xen/gnttab.h>
58 #include <xen/xenbus/xenbusvar.h>
59 #include <xen/xenbus/xenbusb.h>
60 
61 /*------------------ Private Device Attachment Functions  --------------------*/
62 /**
63  * \brief Probe for the existance of the XenBus front bus.
64  *
65  * \param dev  NewBus device_t for this XenBus front bus instance.
66  *
67  * \return  Always returns 0 indicating success.
68  */
69 static int
70 xenbusb_front_probe(device_t dev)
71 {
72 	device_set_desc(dev, "Xen Frontend Devices");
73 
74 	return (0);
75 }
76 
77 /**
78  * \brief Attach the XenBus front bus.
79  *
80  * \param dev  NewBus device_t for this XenBus front bus instance.
81  *
82  * \return  On success, 0. Otherwise an errno value indicating the
83  *          type of failure.
84  */
85 static int
86 xenbusb_front_attach(device_t dev)
87 {
88 	return (xenbusb_attach(dev, "device", /*id_components*/1));
89 }
90 
91 /**
92  * \brief Enumerate all devices of the given type on this bus.
93  *
94  * \param dev   NewBus device_t for this XenBus front bus instance.
95  * \param type  String indicating the device sub-tree (e.g. "vfb", "vif")
96  *              to enumerate.
97  *
98  * \return  On success, 0. Otherwise an errno value indicating the
99  *          type of failure.
100  *
101  * Devices that are found are entered into the NewBus hierarchy via
102  * xenbusb_add_device().  xenbusb_add_device() ignores duplicate detects
103  * and ignores duplicate devices, so it can be called unconditionally
104  * for any device found in the XenStore.
105  */
106 static int
107 xenbusb_front_enumerate_type(device_t dev, const char *type)
108 {
109 	struct xenbusb_softc *xbs;
110 	const char **dir;
111 	unsigned int i, count;
112 	int error;
113 
114 	xbs = device_get_softc(dev);
115 	error = xs_directory(XST_NIL, xbs->xbs_node, type, &count, &dir);
116 	if (error)
117 		return (error);
118 	for (i = 0; i < count; i++)
119 		xenbusb_add_device(dev, type, dir[i]);
120 
121 	free(dir, M_XENSTORE);
122 
123 	return (0);
124 }
125 
126 /**
127  * \brief Determine and store the XenStore path for the other end of
128  *        a split device whose local end is represented by ivars.
129  *
130  * If successful, the xd_otherend_path field of the child's instance
131  * variables will be updated.
132  *
133  * \param dev    NewBus device_t for this XenBus front bus instance.
134  * \param ivars  Instance variables from the XenBus child device for
135  *               which to perform this function.
136  *
137  * \return  On success, 0. Otherwise an errno value indicating the
138  *          type of failure.
139  */
140 static int
141 xenbusb_front_get_otherend_node(device_t dev, struct xenbus_device_ivars *ivars)
142 {
143 	char *otherend_path;
144 	int error;
145 
146 	if (ivars->xd_otherend_path != NULL) {
147 		free(ivars->xd_otherend_path, M_XENBUS);
148 		ivars->xd_otherend_path = NULL;
149 	}
150 
151 	error = xs_gather(XST_NIL, ivars->xd_node,
152 	    "backend-id", "%i", &ivars->xd_otherend_id,
153 	    "backend", NULL, &otherend_path,
154 	    NULL);
155 
156 	if (error == 0) {
157 		ivars->xd_otherend_path = strdup(otherend_path, M_XENBUS);
158 		ivars->xd_otherend_path_len = strlen(otherend_path);
159 		free(otherend_path, M_XENSTORE);
160 	}
161 	return (error);
162 }
163 
164 /*-------------------- Private Device Attachment Data  -----------------------*/
165 static device_method_t xenbusb_front_methods[] = {
166 	/* Device interface */
167 	DEVMETHOD(device_identify,	xenbusb_identify),
168 	DEVMETHOD(device_probe,         xenbusb_front_probe),
169 	DEVMETHOD(device_attach,        xenbusb_front_attach),
170 	DEVMETHOD(device_detach,        bus_generic_detach),
171 	DEVMETHOD(device_shutdown,      bus_generic_shutdown),
172 	DEVMETHOD(device_suspend,       bus_generic_suspend),
173 	DEVMETHOD(device_resume,        xenbusb_resume),
174 
175 	/* Bus Interface */
176 	DEVMETHOD(bus_print_child,      xenbusb_print_child),
177 	DEVMETHOD(bus_read_ivar,        xenbusb_read_ivar),
178 	DEVMETHOD(bus_write_ivar,       xenbusb_write_ivar),
179 	DEVMETHOD(bus_alloc_resource,   bus_generic_alloc_resource),
180 	DEVMETHOD(bus_release_resource, bus_generic_release_resource),
181 	DEVMETHOD(bus_activate_resource, bus_generic_activate_resource),
182 	DEVMETHOD(bus_deactivate_resource, bus_generic_deactivate_resource),
183 
184 	/* XenBus Bus Interface */
185 	DEVMETHOD(xenbusb_enumerate_type, xenbusb_front_enumerate_type),
186 	DEVMETHOD(xenbusb_get_otherend_node, xenbusb_front_get_otherend_node),
187 	{ 0, 0 }
188 };
189 
190 DEFINE_CLASS_0(xenbusb_front, xenbusb_front_driver, xenbusb_front_methods,
191 	       sizeof(struct xenbusb_softc));
192 devclass_t xenbusb_front_devclass;
193 
194 DRIVER_MODULE(xenbusb_front, xenstore, xenbusb_front_driver,
195 	      xenbusb_front_devclass, 0, 0);
196