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/fs.h>
  42 #include <linux/completion.h>
  43 #include <linux/init.h>
  44 #include <linux/slab.h>
  45 #include <xen/interface/xen.h>
  46 #include <xen/interface/grant_table.h>
  47 #include <xen/interface/io/xenbus.h>
  48 #include <xen/interface/io/xs_wire.h>
  49
  50 #define XENBUS_MAX_RING_GRANT_ORDER 4
  51 #define XENBUS_MAX_RING_GRANTS      (1U << XENBUS_MAX_RING_GRANT_ORDER)
  52 #define INVALID_GRANT_HANDLE       (~0U)
  53
  54 /* Register callback to watch this node. */
  55 struct xenbus_watch
  56 {
  57         struct list_head list;
  58
  59         /* Path being watched. */
  60         const char *node;
  61
  62         /* Callback (executed in a process context with no locks held). */
  63         void (*callback)(struct xenbus_watch *,
  64                          const char *path, const char *token);
  65 };
  66
  67
  68 /* A xenbus device. */
  69 struct xenbus_device {
  70         const char *devicetype;
  71         const char *nodename;
  72         const char *otherend;
  73         int otherend_id;
  74         struct xenbus_watch otherend_watch;
  75         struct device dev;
  76         enum xenbus_state state;
  77         struct completion down;
  78         struct work_struct work;
  79 };
  80
  81 static inline struct xenbus_device *to_xenbus_device(struct device *dev)
  82 {
  83         return container_of(dev, struct xenbus_device, dev);
  84 }
  85
  86 struct xenbus_device_id
  87 {
  88         /* .../device/<device_type>/<identifier> */
  89         char devicetype[32];    /* General class of device. */
  90 };
  91
  92 /* A xenbus driver. */
  93 struct xenbus_driver {
  94         const char *name;       /* defaults to ids[0].devicetype */
  95         const struct xenbus_device_id *ids;
  96         bool allow_rebind; /* avoid setting xenstore closed during remove */
  97         int (*probe)(struct xenbus_device *dev,
  98                      const struct xenbus_device_id *id);
  99         void (*otherend_changed)(struct xenbus_device *dev,
 100                                  enum xenbus_state backend_state);
 101         int (*remove)(struct xenbus_device *dev);
 102         int (*suspend)(struct xenbus_device *dev);
 103         int (*resume)(struct xenbus_device *dev);
 104         int (*uevent)(struct xenbus_device *, struct kobj_uevent_env *);
 105         struct device_driver driver;
 106         int (*read_otherend_details)(struct xenbus_device *dev);
 107         int (*is_ready)(struct xenbus_device *dev);
 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 *drv,
 116                                             struct module *owner,
 117                                             const char *mod_name);
 118 int __must_check __xenbus_register_backend(struct xenbus_driver *drv,
 119                                            struct module *owner,
 120                                            const char *mod_name);
 121
 122 #define xenbus_register_frontend(drv) \
 123         __xenbus_register_frontend(drv, THIS_MODULE, KBUILD_MODNAME)
 124 #define xenbus_register_backend(drv) \
 125         __xenbus_register_backend(drv, THIS_MODULE, KBUILD_MODNAME)
 126
 127 void xenbus_unregister_driver(struct xenbus_driver *drv);
 128
 129 struct xenbus_transaction
 130 {
 131         u32 id;
 132 };
 133
 134 /* Nil transaction ID. */
 135 #define XBT_NIL ((struct xenbus_transaction) { 0 })
 136
 137 char **xenbus_directory(struct xenbus_transaction t,
 138                         const char *dir, const char *node, unsigned int *num);
 139 void *xenbus_read(struct xenbus_transaction t,
 140                   const char *dir, const char *node, unsigned int *len);
 141 int xenbus_write(struct xenbus_transaction t,
 142                  const char *dir, const char *node, const char *string);
 143 int xenbus_mkdir(struct xenbus_transaction t,
 144                  const char *dir, const char *node);
 145 int xenbus_exists(struct xenbus_transaction t,
 146                   const char *dir, const char *node);
 147 int xenbus_rm(struct xenbus_transaction t, const char *dir, const char *node);
 148 int xenbus_transaction_start(struct xenbus_transaction *t);
 149 int xenbus_transaction_end(struct xenbus_transaction t, int abort);
 150
 151 /* Single read and scanf: returns -errno or num scanned if > 0. */
 152 __scanf(4, 5)
 153 int xenbus_scanf(struct xenbus_transaction t,
 154                  const char *dir, const char *node, const char *fmt, ...);
 155
 156 /* Read an (optional) unsigned value. */
 157 unsigned int xenbus_read_unsigned(const char *dir, const char *node,
 158                                   unsigned int default_val);
 159
 160 /* Single printf and write: returns -errno or 0. */
 161 __printf(4, 5)
 162 int xenbus_printf(struct xenbus_transaction t,
 163                   const char *dir, const char *node, const char *fmt, ...);
 164
 165 /* Generic read function: NULL-terminated triples of name,
 166  * sprintf-style type string, and pointer. Returns 0 or errno.*/
 167 int xenbus_gather(struct xenbus_transaction t, const char *dir, ...);
 168
 169 /* notifer routines for when the xenstore comes up */
 170 extern int xenstored_ready;
 171 int register_xenstore_notifier(struct notifier_block *nb);
 172 void unregister_xenstore_notifier(struct notifier_block *nb);
 173
 174 int register_xenbus_watch(struct xenbus_watch *watch);
 175 void unregister_xenbus_watch(struct xenbus_watch *watch);
 176 void xs_suspend(void);
 177 void xs_resume(void);
 178 void xs_suspend_cancel(void);
 179
 180 struct work_struct;
 181
 182 void xenbus_probe(struct work_struct *);
 183
 184 #define XENBUS_IS_ERR_READ(str) ({                      \
 185         if (!IS_ERR(str) && strlen(str) == 0) {         \
 186                 kfree(str);                             \
 187                 str = ERR_PTR(-ERANGE);                 \
 188         }                                               \
 189         IS_ERR(str);                                    \
 190 })
 191
 192 #define XENBUS_EXIST_ERR(err) ((err) == -ENOENT || (err) == -ERANGE)
 193
 194 int xenbus_watch_path(struct xenbus_device *dev, const char *path,
 195                       struct xenbus_watch *watch,
 196                       void (*callback)(struct xenbus_watch *,
 197                                        const char *, const char *));
 198 __printf(4, 5)
 199 int xenbus_watch_pathfmt(struct xenbus_device *dev, struct xenbus_watch *watch,
 200                          void (*callback)(struct xenbus_watch *,
 201                                           const char *, const char *),
 202                          const char *pathfmt, ...);
 203
 204 int xenbus_switch_state(struct xenbus_device *dev, enum xenbus_state new_state);
 205 int xenbus_grant_ring(struct xenbus_device *dev, void *vaddr,
 206                       unsigned int nr_pages, grant_ref_t *grefs);
 207 int xenbus_map_ring_valloc(struct xenbus_device *dev, grant_ref_t *gnt_refs,
 208                            unsigned int nr_grefs, void **vaddr);
 209 int xenbus_map_ring(struct xenbus_device *dev,
 210                     grant_ref_t *gnt_refs, unsigned int nr_grefs,
 211                     grant_handle_t *handles, unsigned long *vaddrs,
 212                     bool *leaked);
 213
 214 int xenbus_unmap_ring_vfree(struct xenbus_device *dev, void *vaddr);
 215 int xenbus_unmap_ring(struct xenbus_device *dev,
 216                       grant_handle_t *handles, unsigned int nr_handles,
 217                       unsigned long *vaddrs);
 218
 219 int xenbus_alloc_evtchn(struct xenbus_device *dev, int *port);
 220 int xenbus_free_evtchn(struct xenbus_device *dev, int port);
 221
 222 enum xenbus_state xenbus_read_driver_state(const char *path);
 223
 224 __printf(3, 4)
 225 void xenbus_dev_error(struct xenbus_device *dev, int err, const char *fmt, ...);
 226 __printf(3, 4)
 227 void xenbus_dev_fatal(struct xenbus_device *dev, int err, const char *fmt, ...);
 228
 229 const char *xenbus_strstate(enum xenbus_state state);
 230 int xenbus_dev_is_online(struct xenbus_device *dev);
 231 int xenbus_frontend_closed(struct xenbus_device *dev);
 232
 233 extern const struct file_operations xen_xenbus_fops;
 234 extern struct xenstore_domain_interface *xen_store_interface;
 235 extern int xen_store_evtchn;
 236
 237 #endif /* _XEN_XENBUS_H */