2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
4 * Core definitions and data structures shareable across OS platforms.
6 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
8 * Copyright (c) 2010 Spectra Logic Corporation
9 * Copyright (C) 2008 Doug Rabson
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39 #ifndef _XEN_XENBUS_XENBUSB_H
40 #define _XEN_XENBUS_XENBUSB_H
45 * Datastructures and function declarations for use in implementing
46 * bus attachements (e.g. frontend and backend device buses) for XenBus.
50 * Enumeration of state flag values for the xbs_flags field of
51 * the xenbusb_softc structure.
55 XBS_ATTACH_CH_ACTIVE = 0x01
59 * \brief Container for all state needed to manage a Xenbus Bus
62 struct xenbusb_softc {
64 * XenStore watch used to monitor the subtree of the
65 * XenStore where devices for this bus attachment arrive
68 struct xs_watch xbs_device_watch;
70 /** Mutex used to protect fields of the xenbusb_softc. */
74 xenbusb_softc_flag xbs_flags;
77 * A dedicated task for processing child arrival and
80 struct task xbs_probe_children;
83 * Config Hook used to block boot processing until
84 * XenBus devices complete their connection processing
87 struct intr_config_hook xbs_attach_ch;
90 * The number of children for this bus that are still
91 * in the connecting (to other VMs) state. This variable
92 * is used to determine when to release xbs_attach_ch.
94 u_int xbs_connecting_children;
96 /** The NewBus device_t for this bus attachment. */
100 * The VM relative path to the XenStore subtree this
101 * bus attachment manages.
103 const char *xbs_node;
106 * The number of path components (strings separated by the '/'
107 * character) that make up the device ID on this bus.
109 u_int xbs_id_components;
113 * Enumeration of state flag values for the xbs_flags field of
114 * the xenbusb_softc structure.
118 * This device is contributing to the xbs_connecting_children
119 * count of its parent bus.
121 XDF_CONNECTING = 0x01
124 /** Instance variables for devices on a XenBus bus. */
125 struct xenbus_device_ivars {
127 * XenStore watch used to monitor the subtree of the
128 * XenStore where information about the otherend of
129 * the split Xen device this device instance represents.
131 struct xs_watch xd_otherend_watch;
134 * XenStore watch used to monitor the XenStore sub-tree
135 * associated with this device. This watch will fire
136 * for modifications that we make from our domain as
137 * well as for those made by the control domain.
139 struct xs_watch xd_local_watch;
141 /** Sleepable lock used to protect instance data. */
145 xenbus_dev_flag xd_flags;
147 /** The NewBus device_t for this XenBus device instance. */
151 * The VM relative path to the XenStore subtree representing
152 * this VMs half of this device.
156 /** The length of xd_node. */
159 /** XenBus device type ("vbd", "vif", etc.). */
163 * Cached version of <xd_node>/state node in the XenStore.
165 enum xenbus_state xd_state;
167 /** The VM identifier of the other end of this split device. */
171 * The path to the subtree of the XenStore where information
172 * about the otherend of this split device instance.
174 char *xd_otherend_path;
176 /** The length of xd_otherend_path. */
177 int xd_otherend_path_len;
181 * \brief Identify instances of this device type in the system.
183 * \param driver The driver performing this identify action.
184 * \param parent The NewBus parent device for any devices this method adds.
186 void xenbusb_identify(driver_t *driver __unused, device_t parent);
189 * \brief Perform common XenBus bus attach processing.
191 * \param dev The NewBus device representing this XenBus bus.
192 * \param bus_node The XenStore path to the XenStore subtree for
194 * \param id_components The number of '/' separated path components that
195 * make up a unique device ID on this XenBus bus.
197 * \return On success, 0. Otherwise an errno value indicating the
200 * Intiailizes the softc for this bus, installs an interrupt driven
201 * configuration hook to block boot processing until XenBus devices fully
202 * configure, performs an initial probe/attach of the bus, and registers
203 * a XenStore watch so we are notified when the bus topology changes.
205 int xenbusb_attach(device_t dev, char *bus_node, u_int id_components);
208 * \brief Perform common XenBus bus resume handling.
210 * \param dev The NewBus device representing this XenBus bus.
212 * \return On success, 0. Otherwise an errno value indicating the
215 int xenbusb_resume(device_t dev);
218 * \brief Pretty-prints information about a child of a XenBus bus.
220 * \param dev The NewBus device representing this XenBus bus.
221 * \param child The NewBus device representing a child of dev%'s XenBus bus.
223 * \return On success, 0. Otherwise an errno value indicating the
226 int xenbusb_print_child(device_t dev, device_t child);
229 * \brief Common XenBus child instance variable read access method.
231 * \param dev The NewBus device representing this XenBus bus.
232 * \param child The NewBus device representing a child of dev%'s XenBus bus.
233 * \param index The index of the instance variable to access.
234 * \param result The value of the instance variable accessed.
236 * \return On success, 0. Otherwise an errno value indicating the
239 int xenbusb_read_ivar(device_t dev, device_t child, int index,
243 * \brief Common XenBus child instance variable write access method.
245 * \param dev The NewBus device representing this XenBus bus.
246 * \param child The NewBus device representing a child of dev%'s XenBus bus.
247 * \param index The index of the instance variable to access.
248 * \param value The new value to set in the instance variable accessed.
250 * \return On success, 0. Otherwise an errno value indicating the
253 int xenbusb_write_ivar(device_t dev, device_t child, int index,
257 * \brief Common XenBus method implementing responses to peer state changes.
259 * \param bus The XenBus bus parent of child.
260 * \param child The XenBus child whose peer stat has changed.
261 * \param state The current state of the peer.
263 void xenbusb_otherend_changed(device_t bus, device_t child,
264 enum xenbus_state state);
267 * \brief Common XenBus method implementing responses to local XenStore changes.
269 * \param bus The XenBus bus parent of child.
270 * \param child The XenBus child whose peer stat has changed.
271 * \param path The tree relative sub-path to the modified node. The empty
272 * string indicates the root of the tree was destroyed.
274 void xenbusb_localend_changed(device_t bus, device_t child, const char *path);
277 * \brief Attempt to add a XenBus device instance to this XenBus bus.
279 * \param dev The NewBus device representing this XenBus bus.
280 * \param type The device type being added (e.g. "vbd", "vif").
281 * \param id The device ID for this device.
283 * \return On success, 0. Otherwise an errno value indicating the
284 * type of failure. Failure indicates that either the
285 * path to this device no longer exists or insufficient
286 * information exists in the XenStore to create a new
289 * If successful, this routine will add a device_t with instance
290 * variable storage to the NewBus device topology. Probe/Attach
291 * processing is not performed by this routine, but must be scheduled
292 * via the xbs_probe_children task. This separation of responsibilities
293 * is required to avoid hanging up the XenStore event delivery thread
294 * with our probe/attach work in the event a device is added via
295 * a callback from the XenStore.
297 int xenbusb_add_device(device_t dev, const char *type, const char *id);
299 #include "xenbusb_if.h"
301 #endif /* _XEN_XENBUS_XENBUSB_H */