linux/include/xen/xenbus.h
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   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. */
  50struct 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. */
  64struct 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};
  74
  75static inline struct xenbus_device *to_xenbus_device(struct device *dev)
  76{
  77        return container_of(dev, struct xenbus_device, dev);
  78}
  79
  80struct xenbus_device_id
  81{
  82        /* .../device/<device_type>/<identifier> */
  83        char devicetype[32];    /* General class of device. */
  84};
  85
  86/* A xenbus driver. */
  87struct xenbus_driver {
  88        const struct xenbus_device_id *ids;
  89        int (*probe)(struct xenbus_device *dev,
  90                     const struct xenbus_device_id *id);
  91        void (*otherend_changed)(struct xenbus_device *dev,
  92                                 enum xenbus_state backend_state);
  93        int (*remove)(struct xenbus_device *dev);
  94        int (*suspend)(struct xenbus_device *dev);
  95        int (*resume)(struct xenbus_device *dev);
  96        int (*uevent)(struct xenbus_device *, struct kobj_uevent_env *);
  97        struct device_driver driver;
  98        int (*read_otherend_details)(struct xenbus_device *dev);
  99        int (*is_ready)(struct xenbus_device *dev);
 100};
 101
 102#define DEFINE_XENBUS_DRIVER(var, drvname, methods...)          \
 103struct xenbus_driver var ## _driver = {                         \
 104        .driver.name = drvname + 0 ?: var ## _ids->devicetype,  \
 105        .driver.owner = THIS_MODULE,                            \
 106        .ids = var ## _ids, ## methods                          \
 107}
 108
 109static inline struct xenbus_driver *to_xenbus_driver(struct device_driver *drv)
 110{
 111        return container_of(drv, struct xenbus_driver, driver);
 112}
 113
 114int __must_check xenbus_register_frontend(struct xenbus_driver *);
 115int __must_check xenbus_register_backend(struct xenbus_driver *);
 116
 117void xenbus_unregister_driver(struct xenbus_driver *drv);
 118
 119struct xenbus_transaction
 120{
 121        u32 id;
 122};
 123
 124/* Nil transaction ID. */
 125#define XBT_NIL ((struct xenbus_transaction) { 0 })
 126
 127char **xenbus_directory(struct xenbus_transaction t,
 128                        const char *dir, const char *node, unsigned int *num);
 129void *xenbus_read(struct xenbus_transaction t,
 130                  const char *dir, const char *node, unsigned int *len);
 131int xenbus_write(struct xenbus_transaction t,
 132                 const char *dir, const char *node, const char *string);
 133int xenbus_mkdir(struct xenbus_transaction t,
 134                 const char *dir, const char *node);
 135int xenbus_exists(struct xenbus_transaction t,
 136                  const char *dir, const char *node);
 137int xenbus_rm(struct xenbus_transaction t, const char *dir, const char *node);
 138int xenbus_transaction_start(struct xenbus_transaction *t);
 139int xenbus_transaction_end(struct xenbus_transaction t, int abort);
 140
 141/* Single read and scanf: returns -errno or num scanned if > 0. */
 142__scanf(4, 5)
 143int xenbus_scanf(struct xenbus_transaction t,
 144                 const char *dir, const char *node, const char *fmt, ...);
 145
 146/* Single printf and write: returns -errno or 0. */
 147__printf(4, 5)
 148int xenbus_printf(struct xenbus_transaction t,
 149                  const char *dir, const char *node, const char *fmt, ...);
 150
 151/* Generic read function: NULL-terminated triples of name,
 152 * sprintf-style type string, and pointer. Returns 0 or errno.*/
 153int xenbus_gather(struct xenbus_transaction t, const char *dir, ...);
 154
 155/* notifer routines for when the xenstore comes up */
 156extern int xenstored_ready;
 157int register_xenstore_notifier(struct notifier_block *nb);
 158void unregister_xenstore_notifier(struct notifier_block *nb);
 159
 160int register_xenbus_watch(struct xenbus_watch *watch);
 161void unregister_xenbus_watch(struct xenbus_watch *watch);
 162void xs_suspend(void);
 163void xs_resume(void);
 164void xs_suspend_cancel(void);
 165
 166/* Used by xenbus_dev to borrow kernel's store connection. */
 167void *xenbus_dev_request_and_reply(struct xsd_sockmsg *msg);
 168
 169struct work_struct;
 170
 171/* Prepare for domain suspend: then resume or cancel the suspend. */
 172void xenbus_suspend(void);
 173void xenbus_resume(void);
 174void xenbus_probe(struct work_struct *);
 175void xenbus_suspend_cancel(void);
 176
 177#define XENBUS_IS_ERR_READ(str) ({                      \
 178        if (!IS_ERR(str) && strlen(str) == 0) {         \
 179                kfree(str);                             \
 180                str = ERR_PTR(-ERANGE);                 \
 181        }                                               \
 182        IS_ERR(str);                                    \
 183})
 184
 185#define XENBUS_EXIST_ERR(err) ((err) == -ENOENT || (err) == -ERANGE)
 186
 187int xenbus_watch_path(struct xenbus_device *dev, const char *path,
 188                      struct xenbus_watch *watch,
 189                      void (*callback)(struct xenbus_watch *,
 190                                       const char **, unsigned int));
 191__printf(4, 5)
 192int xenbus_watch_pathfmt(struct xenbus_device *dev, struct xenbus_watch *watch,
 193                         void (*callback)(struct xenbus_watch *,
 194                                          const char **, unsigned int),
 195                         const char *pathfmt, ...);
 196
 197int xenbus_switch_state(struct xenbus_device *dev, enum xenbus_state new_state);
 198int xenbus_grant_ring(struct xenbus_device *dev, unsigned long ring_mfn);
 199int xenbus_map_ring_valloc(struct xenbus_device *dev,
 200                           int gnt_ref, void **vaddr);
 201int xenbus_map_ring(struct xenbus_device *dev, int gnt_ref,
 202                           grant_handle_t *handle, void *vaddr);
 203
 204int xenbus_unmap_ring_vfree(struct xenbus_device *dev, void *vaddr);
 205int xenbus_unmap_ring(struct xenbus_device *dev,
 206                      grant_handle_t handle, void *vaddr);
 207
 208int xenbus_alloc_evtchn(struct xenbus_device *dev, int *port);
 209int xenbus_bind_evtchn(struct xenbus_device *dev, int remote_port, int *port);
 210int xenbus_free_evtchn(struct xenbus_device *dev, int port);
 211
 212enum xenbus_state xenbus_read_driver_state(const char *path);
 213
 214__printf(3, 4)
 215void xenbus_dev_error(struct xenbus_device *dev, int err, const char *fmt, ...);
 216__printf(3, 4)
 217void xenbus_dev_fatal(struct xenbus_device *dev, int err, const char *fmt, ...);
 218
 219const char *xenbus_strstate(enum xenbus_state state);
 220int xenbus_dev_is_online(struct xenbus_device *dev);
 221int xenbus_frontend_closed(struct xenbus_device *dev);
 222
 223#endif /* _XEN_XENBUS_H */
 224
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