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 <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(struct work_struct *);
 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 */