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
62/*------------------ Private Device Attachment Functions  --------------------*/
63/**
64 * \brief Probe for the existance of the XenBus front bus.
65 *
66 * \param dev  NewBus device_t for this XenBus front bus instance.
67 *
68 * \return  Always returns 0 indicating success.
69 */
70static int
71xenbusb_front_probe(device_t dev)
72{
73	device_set_desc(dev, "Xen Frontend Devices");
74
75	return (0);
76}
77
78/**
79 * \brief Attach the XenBus front bus.
80 *
81 * \param dev  NewBus device_t for this XenBus front bus instance.
82 *
83 * \return  On success, 0. Otherwise an errno value indicating the
84 *          type of failure.
85 */
86static int
87xenbusb_front_attach(device_t dev)
88{
89	return (xenbusb_attach(dev, "device", /*id_components*/1));
90}
91
92/**
93 * \brief Enumerate all devices of the given type on this bus.
94 *
95 * \param dev   NewBus device_t for this XenBus front bus instance.
96 * \param type  String indicating the device sub-tree (e.g. "vfb", "vif")
97 *              to enumerate.
98 *
99 * \return  On success, 0. Otherwise an errno value indicating the
100 *          type of failure.
101 *
102 * Devices that are found are entered into the NewBus hierarchy via
103 * xenbusb_add_device().  xenbusb_add_device() ignores duplicate detects
104 * and ignores duplicate devices, so it can be called unconditionally
105 * for any device found in the XenStore.
106 */
107static int
108xenbusb_front_enumerate_type(device_t dev, const char *type)
109{
110	struct xenbusb_softc *xbs;
111	const char **dir;
112	unsigned int i, count;
113	int error;
114
115	xbs = device_get_softc(dev);
116	error = xs_directory(XST_NIL, xbs->xbs_node, type, &count, &dir);
117	if (error)
118		return (error);
119	for (i = 0; i < count; i++)
120		xenbusb_add_device(dev, type, dir[i]);
121
122	free(dir, M_XENSTORE);
123
124	return (0);
125}
126
127/**
128 * \brief Determine and store the XenStore path for the other end of
129 *        a split device whose local end is represented by ivars.
130 *
131 * If successful, the xd_otherend_path field of the child's instance
132 * variables will be updated.
133 *
134 * \param dev    NewBus device_t for this XenBus front bus instance.
135 * \param ivars  Instance variables from the XenBus child device for
136 *               which to perform this function.
137 *
138 * \return  On success, 0. Otherwise an errno value indicating the
139 *          type of failure.
140 */
141static int
142xenbusb_front_get_otherend_node(device_t dev, struct xenbus_device_ivars *ivars)
143{
144	char *otherend_path;
145	int error;
146
147	if (ivars->xd_otherend_path != NULL) {
148		free(ivars->xd_otherend_path, M_XENBUS);
149		ivars->xd_otherend_path = NULL;
150	}
151
152	error = xs_gather(XST_NIL, ivars->xd_node,
153	    "backend-id", "%i", &ivars->xd_otherend_id,
154	    "backend", NULL, &otherend_path,
155	    NULL);
156
157	if (error == 0) {
158		ivars->xd_otherend_path = strdup(otherend_path, M_XENBUS);
159		ivars->xd_otherend_path_len = strlen(otherend_path);
160		free(otherend_path, M_XENSTORE);
161	}
162	return (error);
163}
164
165/*-------------------- Private Device Attachment Data  -----------------------*/
166static device_method_t xenbusb_front_methods[] = {
167	/* Device interface */
168	DEVMETHOD(device_identify,	xenbusb_identify),
169	DEVMETHOD(device_probe,         xenbusb_front_probe),
170	DEVMETHOD(device_attach,        xenbusb_front_attach),
171	DEVMETHOD(device_detach,        bus_generic_detach),
172	DEVMETHOD(device_shutdown,      bus_generic_shutdown),
173	DEVMETHOD(device_suspend,       bus_generic_suspend),
174	DEVMETHOD(device_resume,        xenbusb_resume),
175
176	/* Bus Interface */
177	DEVMETHOD(bus_print_child,      xenbusb_print_child),
178	DEVMETHOD(bus_read_ivar,        xenbusb_read_ivar),
179	DEVMETHOD(bus_write_ivar,       xenbusb_write_ivar),
180	DEVMETHOD(bus_alloc_resource,   bus_generic_alloc_resource),
181	DEVMETHOD(bus_release_resource, bus_generic_release_resource),
182	DEVMETHOD(bus_activate_resource, bus_generic_activate_resource),
183	DEVMETHOD(bus_deactivate_resource, bus_generic_deactivate_resource),
184
185	/* XenBus Bus Interface */
186	DEVMETHOD(xenbusb_enumerate_type, xenbusb_front_enumerate_type),
187	DEVMETHOD(xenbusb_get_otherend_node, xenbusb_front_get_otherend_node),
188	{ 0, 0 }
189};
190
191DEFINE_CLASS_0(xenbusb_front, xenbusb_front_driver, xenbusb_front_methods,
192	       sizeof(struct xenbusb_softc));
193devclass_t xenbusb_front_devclass;
194
195DRIVER_MODULE(xenbusb_front, xenstore, xenbusb_front_driver,
196	      xenbusb_front_devclass, 0, 0);
197