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 #define XENBUS_MAX_RING_GRANT_ORDER 4
  50 #define XENBUS_MAX_RING_GRANTS      (1U << XENBUS_MAX_RING_GRANT_ORDER)
  51 #define INVALID_GRANT_HANDLE       (~0U)
  52
  53 /* Register callback to watch this node. */
  54 struct xenbus_watch
  55 {
  56         struct list_head list;
  57
  58         /* Path being watched. */
  59         const char *node;
  60
  61         /* Callback (executed in a process context with no locks held). */
  62         void (*callback)(struct xenbus_watch *,
  63                          const char **vec, unsigned int len);
  64 };
  65
  66
  67 /* A xenbus device. */
  68 struct xenbus_device {
  69         const char *devicetype;
  70         const char *nodename;
  71         const char *otherend;
  72         int otherend_id;
  73         struct xenbus_watch otherend_watch;
  74         struct device dev;
  75         enum xenbus_state state;
  76         struct completion down;
  77         struct work_struct work;
  78 };
  79
  80 static inline struct xenbus_device *to_xenbus_device(struct device *dev)
  81 {
  82         return container_of(dev, struct xenbus_device, dev);
  83 }
  84
  85 struct xenbus_device_id
  86 {
  87         /* .../device/<device_type>/<identifier> */
  88         char devicetype[32];    /* General class of device. */
  89 };
  90
  91 /* A xenbus driver. */
  92 struct xenbus_driver {
  93         const char *name;       /* defaults to ids[0].devicetype */
  94         const struct xenbus_device_id *ids;
  95         int (*probe)(struct xenbus_device *dev,
  96                      const struct xenbus_device_id *id);
  97         void (*otherend_changed)(struct xenbus_device *dev,
  98                                  enum xenbus_state backend_state);
  99         int (*remove)(struct xenbus_device *dev);
 100         int (*suspend)(struct xenbus_device *dev);
 101         int (*resume)(struct xenbus_device *dev);
 102         int (*uevent)(struct xenbus_device *, struct kobj_uevent_env *);
 103         struct device_driver driver;
 104         int (*read_otherend_details)(struct xenbus_device *dev);
 105         int (*is_ready)(struct xenbus_device *dev);
 106 };
 107
 108 static inline struct xenbus_driver *to_xenbus_driver(struct device_driver *drv)
 109 {
 110         return container_of(drv, struct xenbus_driver, driver);
 111 }
 112
 113 int __must_check __xenbus_register_frontend(struct xenbus_driver *drv,
 114                                             struct module *owner,
 115                                             const char *mod_name);
 116 int __must_check __xenbus_register_backend(struct xenbus_driver *drv,
 117                                            struct module *owner,
 118                                            const char *mod_name);
 119
 120 #define xenbus_register_frontend(drv) \
 121         __xenbus_register_frontend(drv, THIS_MODULE, KBUILD_MODNAME)
 122 #define xenbus_register_backend(drv) \
 123         __xenbus_register_backend(drv, THIS_MODULE, KBUILD_MODNAME)
 124
 125 void xenbus_unregister_driver(struct xenbus_driver *drv);
 126
 127 struct xenbus_transaction
 128 {
 129         u32 id;
 130 };
 131
 132 /* Nil transaction ID. */
 133 #define XBT_NIL ((struct xenbus_transaction) { 0 })
 134
 135 char **xenbus_directory(struct xenbus_transaction t,
 136                         const char *dir, const char *node, unsigned int *num);
 137 void *xenbus_read(struct xenbus_transaction t,
 138                   const char *dir, const char *node, unsigned int *len);
 139 int xenbus_write(struct xenbus_transaction t,
 140                  const char *dir, const char *node, const char *string);
 141 int xenbus_mkdir(struct xenbus_transaction t,
 142                  const char *dir, const char *node);
 143 int xenbus_exists(struct xenbus_transaction t,
 144                   const char *dir, const char *node);
 145 int xenbus_rm(struct xenbus_transaction t, const char *dir, const char *node);
 146 int xenbus_transaction_start(struct xenbus_transaction *t);
 147 int xenbus_transaction_end(struct xenbus_transaction t, int abort);
 148
 149 /* Single read and scanf: returns -errno or num scanned if > 0. */
 150 __scanf(4, 5)
 151 int xenbus_scanf(struct xenbus_transaction t,
 152                  const char *dir, const char *node, const char *fmt, ...);
 153
 154 /* Single printf and write: returns -errno or 0. */
 155 __printf(4, 5)
 156 int xenbus_printf(struct xenbus_transaction t,
 157                   const char *dir, const char *node, const char *fmt, ...);
 158
 159 /* Generic read function: NULL-terminated triples of name,
 160  * sprintf-style type string, and pointer. Returns 0 or errno.*/
 161 int xenbus_gather(struct xenbus_transaction t, const char *dir, ...);
 162
 163 /* notifer routines for when the xenstore comes up */
 164 extern int xenstored_ready;
 165 int register_xenstore_notifier(struct notifier_block *nb);
 166 void unregister_xenstore_notifier(struct notifier_block *nb);
 167
 168 int register_xenbus_watch(struct xenbus_watch *watch);
 169 void unregister_xenbus_watch(struct xenbus_watch *watch);
 170 void xs_suspend(void);
 171 void xs_resume(void);
 172 void xs_suspend_cancel(void);
 173
 174 /* Used by xenbus_dev to borrow kernel's store connection. */
 175 void *xenbus_dev_request_and_reply(struct xsd_sockmsg *msg);
 176
 177 struct work_struct;
 178
 179 /* Prepare for domain suspend: then resume or cancel the suspend. */
 180 void xenbus_suspend(void);
 181 void xenbus_resume(void);
 182 void xenbus_probe(struct work_struct *);
 183 void xenbus_suspend_cancel(void);
 184
 185 #define XENBUS_IS_ERR_READ(str) ({                      \
 186         if (!IS_ERR(str) && strlen(str) == 0) {         \
 187                 kfree(str);                             \
 188                 str = ERR_PTR(-ERANGE);                 \
 189         }                                               \
 190         IS_ERR(str);                                    \
 191 })
 192
 193 #define XENBUS_EXIST_ERR(err) ((err) == -ENOENT || (err) == -ERANGE)
 194
 195 int xenbus_watch_path(struct xenbus_device *dev, const char *path,
 196                       struct xenbus_watch *watch,
 197                       void (*callback)(struct xenbus_watch *,
 198                                        const char **, unsigned int));
 199 __printf(4, 5)
 200 int xenbus_watch_pathfmt(struct xenbus_device *dev, struct xenbus_watch *watch,
 201                          void (*callback)(struct xenbus_watch *,
 202                                           const char **, unsigned int),
 203                          const char *pathfmt, ...);
 204
 205 int xenbus_switch_state(struct xenbus_device *dev, enum xenbus_state new_state);
 206 int xenbus_grant_ring(struct xenbus_device *dev, void *vaddr,
 207                       unsigned int nr_pages, grant_ref_t *grefs);
 208 int xenbus_map_ring_valloc(struct xenbus_device *dev, grant_ref_t *gnt_refs,
 209                            unsigned int nr_grefs, void **vaddr);
 210 int xenbus_map_ring(struct xenbus_device *dev,
 211                     grant_ref_t *gnt_refs, unsigned int nr_grefs,
 212                     grant_handle_t *handles, unsigned long *vaddrs,
 213                     bool *leaked);
 214
 215 int xenbus_unmap_ring_vfree(struct xenbus_device *dev, void *vaddr);
 216 int xenbus_unmap_ring(struct xenbus_device *dev,
 217                       grant_handle_t *handles, unsigned int nr_handles,
 218                       unsigned long *vaddrs);
 219
 220 int xenbus_alloc_evtchn(struct xenbus_device *dev, int *port);
 221 int xenbus_free_evtchn(struct xenbus_device *dev, int port);
 222
 223 enum xenbus_state xenbus_read_driver_state(const char *path);
 224
 225 __printf(3, 4)
 226 void xenbus_dev_error(struct xenbus_device *dev, int err, const char *fmt, ...);
 227 __printf(3, 4)
 228 void xenbus_dev_fatal(struct xenbus_device *dev, int err, const char *fmt, ...);
 229
 230 const char *xenbus_strstate(enum xenbus_state state);
 231 int xenbus_dev_is_online(struct xenbus_device *dev);
 232 int xenbus_frontend_closed(struct xenbus_device *dev);
 233
 234 #endif /* _XEN_XENBUS_H */