include/xen/xenbus.h

   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/completion.h>
  42 #include <linux/init.h>
  43 #include <linux/slab.h>
  44 #include <xen/interface/xen.h>
  45 #include <xen/interface/grant_table.h>
  46 #include <xen/interface/io/xenbus.h>
  47 #include <xen/interface/io/xs_wire.h>
  48
  49 /* Register callback to watch this node. */
  50 struct xenbus_watch
  51 {
  52         struct list_head list;
  53
  54         /* Path being watched. */
  55         const char *node;
  56
  57         /* Callback (executed in a process context with no locks held). */
  58         void (*callback)(struct xenbus_watch *,
  59                          const char **vec, unsigned int len);
  60 };
  61
  62
  63 /* A xenbus device. */
  64 struct xenbus_device {
  65         const char *devicetype;
  66         const char *nodename;
  67         const char *otherend;
  68         int otherend_id;
  69         struct xenbus_watch otherend_watch;
  70         struct device dev;
  71         enum xenbus_state state;
  72         struct completion down;
  73         struct work_struct work;
  74 };
  75
  76 static inline struct xenbus_device *to_xenbus_device(struct device *dev)
  77 {
  78         return container_of(dev, struct xenbus_device, dev);
  79 }
  80
  81 struct xenbus_device_id
  82 {
  83         /* .../device/<device_type>/<identifier> */
  84         char devicetype[32];    /* General class of device. */
  85 };
  86
  87 /* A xenbus driver. */
  88 struct xenbus_driver {
  89         const struct xenbus_device_id *ids;
  90         int (*probe)(struct xenbus_device *dev,
  91                      const struct xenbus_device_id *id);
  92         void (*otherend_changed)(struct xenbus_device *dev,
  93                                  enum xenbus_state backend_state);
  94         int (*remove)(struct xenbus_device *dev);
  95         int (*suspend)(struct xenbus_device *dev);
  96         int (*resume)(struct xenbus_device *dev);
  97         int (*uevent)(struct xenbus_device *, struct kobj_uevent_env *);
  98         struct device_driver driver;
  99         int (*read_otherend_details)(struct xenbus_device *dev);
 100         int (*is_ready)(struct xenbus_device *dev);
 101 };
 102
 103 #define DEFINE_XENBUS_DRIVER(var, drvname, methods...)          \
 104 struct xenbus_driver var ## _driver = {                         \
 105         .driver.name = drvname + 0 ?: var ## _ids->devicetype,  \
 106         .driver.owner = THIS_MODULE,                            \
 107         .ids = var ## _ids, ## methods                          \
 108 }
 109
 110 static inline struct xenbus_driver *to_xenbus_driver(struct device_driver *drv)
 111 {
 112         return container_of(drv, struct xenbus_driver, driver);
 113 }
 114
 115 int __must_check xenbus_register_frontend(struct xenbus_driver *);
 116 int __must_check xenbus_register_backend(struct xenbus_driver *);
 117
 118 void xenbus_unregister_driver(struct xenbus_driver *drv);
 119
 120 struct xenbus_transaction
 121 {
 122         u32 id;
 123 };
 124
 125 /* Nil transaction ID. */
 126 #define XBT_NIL ((struct xenbus_transaction) { 0 })
 127
 128 char **xenbus_directory(struct xenbus_transaction t,
 129                         const char *dir, const char *node, unsigned int *num);
 130 void *xenbus_read(struct xenbus_transaction t,
 131                   const char *dir, const char *node, unsigned int *len);
 132 int xenbus_write(struct xenbus_transaction t,
 133                  const char *dir, const char *node, const char *string);
 134 int xenbus_mkdir(struct xenbus_transaction t,
 135                  const char *dir, const char *node);
 136 int xenbus_exists(struct xenbus_transaction t,
 137                   const char *dir, const char *node);
 138 int xenbus_rm(struct xenbus_transaction t, const char *dir, const char *node);
 139 int xenbus_transaction_start(struct xenbus_transaction *t);
 140 int xenbus_transaction_end(struct xenbus_transaction t, int abort);
 141
 142 /* Single read and scanf: returns -errno or num scanned if > 0. */
 143 __scanf(4, 5)
 144 int xenbus_scanf(struct xenbus_transaction t,
 145                  const char *dir, const char *node, const char *fmt, ...);
 146
 147 /* Single printf and write: returns -errno or 0. */
 148 __printf(4, 5)
 149 int xenbus_printf(struct xenbus_transaction t,
 150                   const char *dir, const char *node, const char *fmt, ...);
 151
 152 /* Generic read function: NULL-terminated triples of name,
 153  * sprintf-style type string, and pointer. Returns 0 or errno.*/
 154 int xenbus_gather(struct xenbus_transaction t, const char *dir, ...);
 155
 156 /* notifer routines for when the xenstore comes up */
 157 extern int xenstored_ready;
 158 int register_xenstore_notifier(struct notifier_block *nb);
 159 void unregister_xenstore_notifier(struct notifier_block *nb);
 160
 161 int register_xenbus_watch(struct xenbus_watch *watch);
 162 void unregister_xenbus_watch(struct xenbus_watch *watch);
 163 void xs_suspend(void);
 164 void xs_resume(void);
 165 void xs_suspend_cancel(void);
 166
 167 /* Used by xenbus_dev to borrow kernel's store connection. */
 168 void *xenbus_dev_request_and_reply(struct xsd_sockmsg *msg);
 169
 170 struct work_struct;
 171
 172 /* Prepare for domain suspend: then resume or cancel the suspend. */
 173 void xenbus_suspend(void);
 174 void xenbus_resume(void);
 175 void xenbus_probe(struct work_struct *);
 176 void xenbus_suspend_cancel(void);
 177
 178 #define XENBUS_IS_ERR_READ(str) ({                      \
 179         if (!IS_ERR(str) && strlen(str) == 0) {         \
 180                 kfree(str);                             \
 181                 str = ERR_PTR(-ERANGE);                 \
 182         }                                               \
 183         IS_ERR(str);                                    \
 184 })
 185
 186 #define XENBUS_EXIST_ERR(err) ((err) == -ENOENT || (err) == -ERANGE)
 187
 188 int xenbus_watch_path(struct xenbus_device *dev, const char *path,
 189                       struct xenbus_watch *watch,
 190                       void (*callback)(struct xenbus_watch *,
 191                                        const char **, unsigned int));
 192 __printf(4, 5)
 193 int xenbus_watch_pathfmt(struct xenbus_device *dev, struct xenbus_watch *watch,
 194                          void (*callback)(struct xenbus_watch *,
 195                                           const char **, unsigned int),
 196                          const char *pathfmt, ...);
 197
 198 int xenbus_switch_state(struct xenbus_device *dev, enum xenbus_state new_state);
 199 int xenbus_grant_ring(struct xenbus_device *dev, unsigned long ring_mfn);
 200 int xenbus_map_ring_valloc(struct xenbus_device *dev,
 201                            int gnt_ref, void **vaddr);
 202 int xenbus_map_ring(struct xenbus_device *dev, int gnt_ref,
 203                            grant_handle_t *handle, void *vaddr);
 204
 205 int xenbus_unmap_ring_vfree(struct xenbus_device *dev, void *vaddr);
 206 int xenbus_unmap_ring(struct xenbus_device *dev,
 207                       grant_handle_t handle, void *vaddr);
 208
 209 int xenbus_alloc_evtchn(struct xenbus_device *dev, int *port);
 210 int xenbus_free_evtchn(struct xenbus_device *dev, int port);
 211
 212 enum xenbus_state xenbus_read_driver_state(const char *path);
 213
 214 __printf(3, 4)
 215 void xenbus_dev_error(struct xenbus_device *dev, int err, const char *fmt, ...);
 216 __printf(3, 4)
 217 void xenbus_dev_fatal(struct xenbus_device *dev, int err, const char *fmt, ...);
 218
 219 const char *xenbus_strstate(enum xenbus_state state);
 220 int xenbus_dev_is_online(struct xenbus_device *dev);
 221 int xenbus_frontend_closed(struct xenbus_device *dev);
 222
 223 #endif /* _XEN_XENBUS_H */