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