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 */
69static int
70xenbusb_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 */
85static int
86xenbusb_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 */
106static int
107xenbusb_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 */
140static int
141xenbusb_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  -----------------------*/
165static 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
190DEFINE_CLASS_0(xenbusb_front, xenbusb_front_driver, xenbusb_front_methods,
191	       sizeof(struct xenbusb_softc));
192devclass_t xenbusb_front_devclass;
193
194DRIVER_MODULE(xenbusb_front, xenstore, xenbusb_front_driver,
195	      xenbusb_front_devclass, 0, 0);
196