xref: /openbmc/linux/include/xen/xenbus.h (revision f4c3b83b)
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 #define INVALID_GRANT_HANDLE       (~0U)
55 
56 /* Register callback to watch this node. */
57 struct xenbus_watch
58 {
59 	struct list_head list;
60 
61 	/* Path being watched. */
62 	const char *node;
63 
64 	unsigned int nr_pending;
65 
66 	/*
67 	 * Called just before enqueing new event while a spinlock is held.
68 	 * The event will be discarded if this callback returns false.
69 	 */
70 	bool (*will_handle)(struct xenbus_watch *,
71 			      const char *path, const char *token);
72 
73 	/* Callback (executed in a process context with no locks held). */
74 	void (*callback)(struct xenbus_watch *,
75 			 const char *path, const char *token);
76 };
77 
78 
79 /* A xenbus device. */
80 struct xenbus_device {
81 	const char *devicetype;
82 	const char *nodename;
83 	const char *otherend;
84 	int otherend_id;
85 	struct xenbus_watch otherend_watch;
86 	struct device dev;
87 	enum xenbus_state state;
88 	struct completion down;
89 	struct work_struct work;
90 	struct semaphore reclaim_sem;
91 };
92 
93 static inline struct xenbus_device *to_xenbus_device(struct device *dev)
94 {
95 	return container_of(dev, struct xenbus_device, dev);
96 }
97 
98 struct xenbus_device_id
99 {
100 	/* .../device/<device_type>/<identifier> */
101 	char devicetype[32]; 	/* General class of device. */
102 };
103 
104 /* A xenbus driver. */
105 struct xenbus_driver {
106 	const char *name;       /* defaults to ids[0].devicetype */
107 	const struct xenbus_device_id *ids;
108 	bool allow_rebind; /* avoid setting xenstore closed during remove */
109 	int (*probe)(struct xenbus_device *dev,
110 		     const struct xenbus_device_id *id);
111 	void (*otherend_changed)(struct xenbus_device *dev,
112 				 enum xenbus_state backend_state);
113 	int (*remove)(struct xenbus_device *dev);
114 	int (*suspend)(struct xenbus_device *dev);
115 	int (*resume)(struct xenbus_device *dev);
116 	int (*uevent)(struct xenbus_device *, struct kobj_uevent_env *);
117 	struct device_driver driver;
118 	int (*read_otherend_details)(struct xenbus_device *dev);
119 	int (*is_ready)(struct xenbus_device *dev);
120 	void (*reclaim_memory)(struct xenbus_device *dev);
121 };
122 
123 static inline struct xenbus_driver *to_xenbus_driver(struct device_driver *drv)
124 {
125 	return container_of(drv, struct xenbus_driver, driver);
126 }
127 
128 int __must_check __xenbus_register_frontend(struct xenbus_driver *drv,
129 					    struct module *owner,
130 					    const char *mod_name);
131 int __must_check __xenbus_register_backend(struct xenbus_driver *drv,
132 					   struct module *owner,
133 					   const char *mod_name);
134 
135 #define xenbus_register_frontend(drv) \
136 	__xenbus_register_frontend(drv, THIS_MODULE, KBUILD_MODNAME)
137 #define xenbus_register_backend(drv) \
138 	__xenbus_register_backend(drv, THIS_MODULE, KBUILD_MODNAME)
139 
140 void xenbus_unregister_driver(struct xenbus_driver *drv);
141 
142 struct xenbus_transaction
143 {
144 	u32 id;
145 };
146 
147 /* Nil transaction ID. */
148 #define XBT_NIL ((struct xenbus_transaction) { 0 })
149 
150 char **xenbus_directory(struct xenbus_transaction t,
151 			const char *dir, const char *node, unsigned int *num);
152 void *xenbus_read(struct xenbus_transaction t,
153 		  const char *dir, const char *node, unsigned int *len);
154 int xenbus_write(struct xenbus_transaction t,
155 		 const char *dir, const char *node, const char *string);
156 int xenbus_mkdir(struct xenbus_transaction t,
157 		 const char *dir, const char *node);
158 int xenbus_exists(struct xenbus_transaction t,
159 		  const char *dir, const char *node);
160 int xenbus_rm(struct xenbus_transaction t, const char *dir, const char *node);
161 int xenbus_transaction_start(struct xenbus_transaction *t);
162 int xenbus_transaction_end(struct xenbus_transaction t, int abort);
163 
164 /* Single read and scanf: returns -errno or num scanned if > 0. */
165 __scanf(4, 5)
166 int xenbus_scanf(struct xenbus_transaction t,
167 		 const char *dir, const char *node, const char *fmt, ...);
168 
169 /* Read an (optional) unsigned value. */
170 unsigned int xenbus_read_unsigned(const char *dir, const char *node,
171 				  unsigned int default_val);
172 
173 /* Single printf and write: returns -errno or 0. */
174 __printf(4, 5)
175 int xenbus_printf(struct xenbus_transaction t,
176 		  const char *dir, const char *node, const char *fmt, ...);
177 
178 /* Generic read function: NULL-terminated triples of name,
179  * sprintf-style type string, and pointer. Returns 0 or errno.*/
180 int xenbus_gather(struct xenbus_transaction t, const char *dir, ...);
181 
182 /* notifer routines for when the xenstore comes up */
183 extern int xenstored_ready;
184 int register_xenstore_notifier(struct notifier_block *nb);
185 void unregister_xenstore_notifier(struct notifier_block *nb);
186 
187 int register_xenbus_watch(struct xenbus_watch *watch);
188 void unregister_xenbus_watch(struct xenbus_watch *watch);
189 void xs_suspend(void);
190 void xs_resume(void);
191 void xs_suspend_cancel(void);
192 
193 struct work_struct;
194 
195 void xenbus_probe(void);
196 
197 #define XENBUS_IS_ERR_READ(str) ({			\
198 	if (!IS_ERR(str) && strlen(str) == 0) {		\
199 		kfree(str);				\
200 		str = ERR_PTR(-ERANGE);			\
201 	}						\
202 	IS_ERR(str);					\
203 })
204 
205 #define XENBUS_EXIST_ERR(err) ((err) == -ENOENT || (err) == -ERANGE)
206 
207 int xenbus_watch_path(struct xenbus_device *dev, const char *path,
208 		      struct xenbus_watch *watch,
209 		      bool (*will_handle)(struct xenbus_watch *,
210 					  const char *, const char *),
211 		      void (*callback)(struct xenbus_watch *,
212 				       const char *, const char *));
213 __printf(5, 6)
214 int xenbus_watch_pathfmt(struct xenbus_device *dev, struct xenbus_watch *watch,
215 			 bool (*will_handle)(struct xenbus_watch *,
216 					     const char *, const char *),
217 			 void (*callback)(struct xenbus_watch *,
218 					  const char *, const char *),
219 			 const char *pathfmt, ...);
220 
221 int xenbus_switch_state(struct xenbus_device *dev, enum xenbus_state new_state);
222 int xenbus_grant_ring(struct xenbus_device *dev, void *vaddr,
223 		      unsigned int nr_pages, grant_ref_t *grefs);
224 int xenbus_map_ring_valloc(struct xenbus_device *dev, grant_ref_t *gnt_refs,
225 			   unsigned int nr_grefs, void **vaddr);
226 
227 int xenbus_unmap_ring_vfree(struct xenbus_device *dev, void *vaddr);
228 
229 int xenbus_alloc_evtchn(struct xenbus_device *dev, evtchn_port_t *port);
230 int xenbus_free_evtchn(struct xenbus_device *dev, evtchn_port_t port);
231 
232 enum xenbus_state xenbus_read_driver_state(const char *path);
233 
234 __printf(3, 4)
235 void xenbus_dev_error(struct xenbus_device *dev, int err, const char *fmt, ...);
236 __printf(3, 4)
237 void xenbus_dev_fatal(struct xenbus_device *dev, int err, const char *fmt, ...);
238 
239 const char *xenbus_strstate(enum xenbus_state state);
240 int xenbus_dev_is_online(struct xenbus_device *dev);
241 int xenbus_frontend_closed(struct xenbus_device *dev);
242 
243 extern const struct file_operations xen_xenbus_fops;
244 extern struct xenstore_domain_interface *xen_store_interface;
245 extern int xen_store_evtchn;
246 
247 #endif /* _XEN_XENBUS_H */
248