1 /******************************************************************************
2 * xenbus.h
3 *
4 * Talks to Xen Store to figure out what devices we have.
5 *
6 * Copyright (C) 2005 Rusty Russell, IBM Corporation
7 * Copyright (C) 2005 XenSource Ltd.
8 *
9 * This program is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU General Public License version 2
11 * as published by the Free Software Foundation; or, when distributed
12 * separately from the Linux kernel or incorporated into other
13 * software packages, subject to the following license:
14 *
15 * Permission is hereby granted, free of charge, to any person obtaining a copy
16 * of this source file (the "Software"), to deal in the Software without
17 * restriction, including without limitation the rights to use, copy, modify,
18 * merge, publish, distribute, sublicense, and/or sell copies of the Software,
19 * and to permit persons to whom the Software is furnished to do so, subject to
20 * the following conditions:
21 *
22 * The above copyright notice and this permission notice shall be included in
23 * all copies or substantial portions of the Software.
24 *
25 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
26 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
27 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
28 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
29 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
30 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
31 * IN THE SOFTWARE.
32 */
33
34 #ifndef _XEN_XENBUS_H
35 #define _XEN_XENBUS_H
36
37 #include <linux/device.h>
38 #include <linux/notifier.h>
39 #include <linux/mutex.h>
40 #include <linux/export.h>
41 #include <linux/fs.h>
42 #include <linux/completion.h>
43 #include <linux/init.h>
44 #include <linux/slab.h>
45 #include <linux/semaphore.h>
46 #include <xen/interface/xen.h>
47 #include <xen/interface/grant_table.h>
48 #include <xen/interface/io/xenbus.h>
49 #include <xen/interface/io/xs_wire.h>
50 #include <xen/interface/event_channel.h>
51
52 #define XENBUS_MAX_RING_GRANT_ORDER 4
53 #define XENBUS_MAX_RING_GRANTS (1U << XENBUS_MAX_RING_GRANT_ORDER)
54
55 /* Register callback to watch this node. */
56 struct xenbus_watch
57 {
58 struct list_head list;
59
60 /* Path being watched. */
61 const char *node;
62
63 unsigned int nr_pending;
64
65 /*
66 * Called just before enqueing new event while a spinlock is held.
67 * The event will be discarded if this callback returns false.
68 */
69 bool (*will_handle)(struct xenbus_watch *,
70 const char *path, const char *token);
71
72 /* Callback (executed in a process context with no locks held). */
73 void (*callback)(struct xenbus_watch *,
74 const char *path, const char *token);
75 };
76
77
78 /* A xenbus device. */
79 struct xenbus_device {
80 const char *devicetype;
81 const char *nodename;
82 const char *otherend;
83 int otherend_id;
84 struct xenbus_watch otherend_watch;
85 struct device dev;
86 enum xenbus_state state;
87 struct completion down;
88 struct work_struct work;
89 struct semaphore reclaim_sem;
90
91 /* Event channel based statistics and settings. */
92 atomic_t event_channels;
93 atomic_t events;
94 atomic_t spurious_events;
95 atomic_t jiffies_eoi_delayed;
96 unsigned int spurious_threshold;
97 };
98
to_xenbus_device(struct device * dev)99 static inline struct xenbus_device *to_xenbus_device(struct device *dev)
100 {
101 return container_of(dev, struct xenbus_device, dev);
102 }
103
104 struct xenbus_device_id
105 {
106 /* .../device/<device_type>/<identifier> */
107 char devicetype[32]; /* General class of device. */
108 };
109
110 /* A xenbus driver. */
111 struct xenbus_driver {
112 const char *name; /* defaults to ids[0].devicetype */
113 const struct xenbus_device_id *ids;
114 bool allow_rebind; /* avoid setting xenstore closed during remove */
115 bool not_essential; /* is not mandatory for boot progress */
116 int (*probe)(struct xenbus_device *dev,
117 const struct xenbus_device_id *id);
118 void (*otherend_changed)(struct xenbus_device *dev,
119 enum xenbus_state backend_state);
120 int (*remove)(struct xenbus_device *dev);
121 int (*suspend)(struct xenbus_device *dev);
122 int (*resume)(struct xenbus_device *dev);
123 int (*uevent)(struct xenbus_device *, struct kobj_uevent_env *);
124 struct device_driver driver;
125 int (*read_otherend_details)(struct xenbus_device *dev);
126 int (*is_ready)(struct xenbus_device *dev);
127 void (*reclaim_memory)(struct xenbus_device *dev);
128 };
129
to_xenbus_driver(struct device_driver * drv)130 static inline struct xenbus_driver *to_xenbus_driver(struct device_driver *drv)
131 {
132 return container_of(drv, struct xenbus_driver, driver);
133 }
134
135 int __must_check __xenbus_register_frontend(struct xenbus_driver *drv,
136 struct module *owner,
137 const char *mod_name);
138 int __must_check __xenbus_register_backend(struct xenbus_driver *drv,
139 struct module *owner,
140 const char *mod_name);
141
142 #define xenbus_register_frontend(drv) \
143 __xenbus_register_frontend(drv, THIS_MODULE, KBUILD_MODNAME)
144 #define xenbus_register_backend(drv) \
145 __xenbus_register_backend(drv, THIS_MODULE, KBUILD_MODNAME)
146
147 void xenbus_unregister_driver(struct xenbus_driver *drv);
148
149 struct xenbus_transaction
150 {
151 u32 id;
152 };
153
154 /* Nil transaction ID. */
155 #define XBT_NIL ((struct xenbus_transaction) { 0 })
156
157 char **xenbus_directory(struct xenbus_transaction t,
158 const char *dir, const char *node, unsigned int *num);
159 void *xenbus_read(struct xenbus_transaction t,
160 const char *dir, const char *node, unsigned int *len);
161 int xenbus_write(struct xenbus_transaction t,
162 const char *dir, const char *node, const char *string);
163 int xenbus_mkdir(struct xenbus_transaction t,
164 const char *dir, const char *node);
165 int xenbus_exists(struct xenbus_transaction t,
166 const char *dir, const char *node);
167 int xenbus_rm(struct xenbus_transaction t, const char *dir, const char *node);
168 int xenbus_transaction_start(struct xenbus_transaction *t);
169 int xenbus_transaction_end(struct xenbus_transaction t, int abort);
170
171 /* Single read and scanf: returns -errno or num scanned if > 0. */
172 __scanf(4, 5)
173 int xenbus_scanf(struct xenbus_transaction t,
174 const char *dir, const char *node, const char *fmt, ...);
175
176 /* Read an (optional) unsigned value. */
177 unsigned int xenbus_read_unsigned(const char *dir, const char *node,
178 unsigned int default_val);
179
180 /* Single printf and write: returns -errno or 0. */
181 __printf(4, 5)
182 int xenbus_printf(struct xenbus_transaction t,
183 const char *dir, const char *node, const char *fmt, ...);
184
185 /* Generic read function: NULL-terminated triples of name,
186 * sprintf-style type string, and pointer. Returns 0 or errno.*/
187 int xenbus_gather(struct xenbus_transaction t, const char *dir, ...);
188
189 /* notifer routines for when the xenstore comes up */
190 extern int xenstored_ready;
191 int register_xenstore_notifier(struct notifier_block *nb);
192 void unregister_xenstore_notifier(struct notifier_block *nb);
193
194 int register_xenbus_watch(struct xenbus_watch *watch);
195 void unregister_xenbus_watch(struct xenbus_watch *watch);
196 void xs_suspend(void);
197 void xs_resume(void);
198 void xs_suspend_cancel(void);
199
200 struct work_struct;
201
202 #define XENBUS_IS_ERR_READ(str) ({ \
203 if (!IS_ERR(str) && strlen(str) == 0) { \
204 kfree(str); \
205 str = ERR_PTR(-ERANGE); \
206 } \
207 IS_ERR(str); \
208 })
209
210 #define XENBUS_EXIST_ERR(err) ((err) == -ENOENT || (err) == -ERANGE)
211
212 int xenbus_watch_path(struct xenbus_device *dev, const char *path,
213 struct xenbus_watch *watch,
214 bool (*will_handle)(struct xenbus_watch *,
215 const char *, const char *),
216 void (*callback)(struct xenbus_watch *,
217 const char *, const char *));
218 __printf(5, 6)
219 int xenbus_watch_pathfmt(struct xenbus_device *dev, struct xenbus_watch *watch,
220 bool (*will_handle)(struct xenbus_watch *,
221 const char *, const char *),
222 void (*callback)(struct xenbus_watch *,
223 const char *, const char *),
224 const char *pathfmt, ...);
225
226 int xenbus_switch_state(struct xenbus_device *dev, enum xenbus_state new_state);
227 int xenbus_setup_ring(struct xenbus_device *dev, gfp_t gfp, void **vaddr,
228 unsigned int nr_pages, grant_ref_t *grefs);
229 void xenbus_teardown_ring(void **vaddr, unsigned int nr_pages,
230 grant_ref_t *grefs);
231 int xenbus_map_ring_valloc(struct xenbus_device *dev, grant_ref_t *gnt_refs,
232 unsigned int nr_grefs, void **vaddr);
233
234 int xenbus_unmap_ring_vfree(struct xenbus_device *dev, void *vaddr);
235
236 int xenbus_alloc_evtchn(struct xenbus_device *dev, evtchn_port_t *port);
237 int xenbus_free_evtchn(struct xenbus_device *dev, evtchn_port_t port);
238
239 enum xenbus_state xenbus_read_driver_state(const char *path);
240
241 __printf(3, 4)
242 void xenbus_dev_error(struct xenbus_device *dev, int err, const char *fmt, ...);
243 __printf(3, 4)
244 void xenbus_dev_fatal(struct xenbus_device *dev, int err, const char *fmt, ...);
245
246 const char *xenbus_strstate(enum xenbus_state state);
247 int xenbus_dev_is_online(struct xenbus_device *dev);
248 int xenbus_frontend_closed(struct xenbus_device *dev);
249
250 extern const struct file_operations xen_xenbus_fops;
251 extern struct xenstore_domain_interface *xen_store_interface;
252 extern int xen_store_evtchn;
253
254 #endif /* _XEN_XENBUS_H */
255