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
  55/* Register callback to watch this node. */
  56struct xenbus_watch
  57{
  58        struct list_head list;
  59
  60        /* Path being watched. */
  61        const char *node;
  62
  63        unsigned int nr_pending;
  64
  65        /*
  66         * Called just before enqueing new event while a spinlock is held.
  67         * The event will be discarded if this callback returns false.
  68         */
  69        bool (*will_handle)(struct xenbus_watch *,
  70                              const char *path, const char *token);
  71
  72        /* Callback (executed in a process context with no locks held). */
  73        void (*callback)(struct xenbus_watch *,
  74                         const char *path, const char *token);
  75};
  76
  77
  78/* A xenbus device. */
  79struct xenbus_device {
  80        const char *devicetype;
  81        const char *nodename;
  82        const char *otherend;
  83        int otherend_id;
  84        struct xenbus_watch otherend_watch;
  85        struct device dev;
  86        enum xenbus_state state;
  87        struct completion down;
  88        struct work_struct work;
  89        struct semaphore reclaim_sem;
  90
  91        /* Event channel based statistics and settings. */
  92        atomic_t event_channels;
  93        atomic_t events;
  94        atomic_t spurious_events;
  95        atomic_t jiffies_eoi_delayed;
  96        unsigned int spurious_threshold;
  97};
  98
  99static inline struct xenbus_device *to_xenbus_device(struct device *dev)
 100{
 101        return container_of(dev, struct xenbus_device, dev);
 102}
 103
 104struct xenbus_device_id
 105{
 106        /* .../device/<device_type>/<identifier> */
 107        char devicetype[32];    /* General class of device. */
 108};
 109
 110/* A xenbus driver. */
 111struct xenbus_driver {
 112        const char *name;       /* defaults to ids[0].devicetype */
 113        const struct xenbus_device_id *ids;
 114        bool allow_rebind; /* avoid setting xenstore closed during remove */
 115        bool not_essential;     /* is not mandatory for boot progress */
 116        int (*probe)(struct xenbus_device *dev,
 117                     const struct xenbus_device_id *id);
 118        void (*otherend_changed)(struct xenbus_device *dev,
 119                                 enum xenbus_state backend_state);
 120        int (*remove)(struct xenbus_device *dev);
 121        int (*suspend)(struct xenbus_device *dev);
 122        int (*resume)(struct xenbus_device *dev);
 123        int (*uevent)(struct xenbus_device *, struct kobj_uevent_env *);
 124        struct device_driver driver;
 125        int (*read_otherend_details)(struct xenbus_device *dev);
 126        int (*is_ready)(struct xenbus_device *dev);
 127        void (*reclaim_memory)(struct xenbus_device *dev);
 128};
 129
 130static inline struct xenbus_driver *to_xenbus_driver(struct device_driver *drv)
 131{
 132        return container_of(drv, struct xenbus_driver, driver);
 133}
 134
 135int __must_check __xenbus_register_frontend(struct xenbus_driver *drv,
 136                                            struct module *owner,
 137                                            const char *mod_name);
 138int __must_check __xenbus_register_backend(struct xenbus_driver *drv,
 139                                           struct module *owner,
 140                                           const char *mod_name);
 141
 142#define xenbus_register_frontend(drv) \
 143        __xenbus_register_frontend(drv, THIS_MODULE, KBUILD_MODNAME)
 144#define xenbus_register_backend(drv) \
 145        __xenbus_register_backend(drv, THIS_MODULE, KBUILD_MODNAME)
 146
 147void xenbus_unregister_driver(struct xenbus_driver *drv);
 148
 149struct xenbus_transaction
 150{
 151        u32 id;
 152};
 153
 154/* Nil transaction ID. */
 155#define XBT_NIL ((struct xenbus_transaction) { 0 })
 156
 157char **xenbus_directory(struct xenbus_transaction t,
 158                        const char *dir, const char *node, unsigned int *num);
 159void *xenbus_read(struct xenbus_transaction t,
 160                  const char *dir, const char *node, unsigned int *len);
 161int xenbus_write(struct xenbus_transaction t,
 162                 const char *dir, const char *node, const char *string);
 163int xenbus_mkdir(struct xenbus_transaction t,
 164                 const char *dir, const char *node);
 165int xenbus_exists(struct xenbus_transaction t,
 166                  const char *dir, const char *node);
 167int xenbus_rm(struct xenbus_transaction t, const char *dir, const char *node);
 168int xenbus_transaction_start(struct xenbus_transaction *t);
 169int xenbus_transaction_end(struct xenbus_transaction t, int abort);
 170
 171/* Single read and scanf: returns -errno or num scanned if > 0. */
 172__scanf(4, 5)
 173int xenbus_scanf(struct xenbus_transaction t,
 174                 const char *dir, const char *node, const char *fmt, ...);
 175
 176/* Read an (optional) unsigned value. */
 177unsigned int xenbus_read_unsigned(const char *dir, const char *node,
 178                                  unsigned int default_val);
 179
 180/* Single printf and write: returns -errno or 0. */
 181__printf(4, 5)
 182int xenbus_printf(struct xenbus_transaction t,
 183                  const char *dir, const char *node, const char *fmt, ...);
 184
 185/* Generic read function: NULL-terminated triples of name,
 186 * sprintf-style type string, and pointer. Returns 0 or errno.*/
 187int xenbus_gather(struct xenbus_transaction t, const char *dir, ...);
 188
 189/* notifer routines for when the xenstore comes up */
 190extern int xenstored_ready;
 191int register_xenstore_notifier(struct notifier_block *nb);
 192void unregister_xenstore_notifier(struct notifier_block *nb);
 193
 194int register_xenbus_watch(struct xenbus_watch *watch);
 195void unregister_xenbus_watch(struct xenbus_watch *watch);
 196void xs_suspend(void);
 197void xs_resume(void);
 198void xs_suspend_cancel(void);
 199
 200struct work_struct;
 201
 202#define XENBUS_IS_ERR_READ(str) ({                      \
 203        if (!IS_ERR(str) && strlen(str) == 0) {         \
 204                kfree(str);                             \
 205                str = ERR_PTR(-ERANGE);                 \
 206        }                                               \
 207        IS_ERR(str);                                    \
 208})
 209
 210#define XENBUS_EXIST_ERR(err) ((err) == -ENOENT || (err) == -ERANGE)
 211
 212int xenbus_watch_path(struct xenbus_device *dev, const char *path,
 213                      struct xenbus_watch *watch,
 214                      bool (*will_handle)(struct xenbus_watch *,
 215                                          const char *, const char *),
 216                      void (*callback)(struct xenbus_watch *,
 217                                       const char *, const char *));
 218__printf(5, 6)
 219int xenbus_watch_pathfmt(struct xenbus_device *dev, struct xenbus_watch *watch,
 220                         bool (*will_handle)(struct xenbus_watch *,
 221                                             const char *, const char *),
 222                         void (*callback)(struct xenbus_watch *,
 223                                          const char *, const char *),
 224                         const char *pathfmt, ...);
 225
 226int xenbus_switch_state(struct xenbus_device *dev, enum xenbus_state new_state);
 227int xenbus_grant_ring(struct xenbus_device *dev, void *vaddr,
 228                      unsigned int nr_pages, grant_ref_t *grefs);
 229int xenbus_map_ring_valloc(struct xenbus_device *dev, grant_ref_t *gnt_refs,
 230                           unsigned int nr_grefs, void **vaddr);
 231
 232int xenbus_unmap_ring_vfree(struct xenbus_device *dev, void *vaddr);
 233
 234int xenbus_alloc_evtchn(struct xenbus_device *dev, evtchn_port_t *port);
 235int xenbus_free_evtchn(struct xenbus_device *dev, evtchn_port_t port);
 236
 237enum xenbus_state xenbus_read_driver_state(const char *path);
 238
 239__printf(3, 4)
 240void xenbus_dev_error(struct xenbus_device *dev, int err, const char *fmt, ...);
 241__printf(3, 4)
 242void xenbus_dev_fatal(struct xenbus_device *dev, int err, const char *fmt, ...);
 243
 244const char *xenbus_strstate(enum xenbus_state state);
 245int xenbus_dev_is_online(struct xenbus_device *dev);
 246int xenbus_frontend_closed(struct xenbus_device *dev);
 247
 248extern const struct file_operations xen_xenbus_fops;
 249extern struct xenstore_domain_interface *xen_store_interface;
 250extern int xen_store_evtchn;
 251
 252#endif /* _XEN_XENBUS_H */
 253