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        int (*probe)(struct xenbus_device *dev,
 116                     const struct xenbus_device_id *id);
 117        void (*otherend_changed)(struct xenbus_device *dev,
 118                                 enum xenbus_state backend_state);
 119        int (*remove)(struct xenbus_device *dev);
 120        int (*suspend)(struct xenbus_device *dev);
 121        int (*resume)(struct xenbus_device *dev);
 122        int (*uevent)(struct xenbus_device *, struct kobj_uevent_env *);
 123        struct device_driver driver;
 124        int (*read_otherend_details)(struct xenbus_device *dev);
 125        int (*is_ready)(struct xenbus_device *dev);
 126        void (*reclaim_memory)(struct xenbus_device *dev);
 127};
 128
 129static inline struct xenbus_driver *to_xenbus_driver(struct device_driver *drv)
 130{
 131        return container_of(drv, struct xenbus_driver, driver);
 132}
 133
 134int __must_check __xenbus_register_frontend(struct xenbus_driver *drv,
 135                                            struct module *owner,
 136                                            const char *mod_name);
 137int __must_check __xenbus_register_backend(struct xenbus_driver *drv,
 138                                           struct module *owner,
 139                                           const char *mod_name);
 140
 141#define xenbus_register_frontend(drv) \
 142        __xenbus_register_frontend(drv, THIS_MODULE, KBUILD_MODNAME)
 143#define xenbus_register_backend(drv) \
 144        __xenbus_register_backend(drv, THIS_MODULE, KBUILD_MODNAME)
 145
 146void xenbus_unregister_driver(struct xenbus_driver *drv);
 147
 148struct xenbus_transaction
 149{
 150        u32 id;
 151};
 152
 153/* Nil transaction ID. */
 154#define XBT_NIL ((struct xenbus_transaction) { 0 })
 155
 156char **xenbus_directory(struct xenbus_transaction t,
 157                        const char *dir, const char *node, unsigned int *num);
 158void *xenbus_read(struct xenbus_transaction t,
 159                  const char *dir, const char *node, unsigned int *len);
 160int xenbus_write(struct xenbus_transaction t,
 161                 const char *dir, const char *node, const char *string);
 162int xenbus_mkdir(struct xenbus_transaction t,
 163                 const char *dir, const char *node);
 164int xenbus_exists(struct xenbus_transaction t,
 165                  const char *dir, const char *node);
 166int xenbus_rm(struct xenbus_transaction t, const char *dir, const char *node);
 167int xenbus_transaction_start(struct xenbus_transaction *t);
 168int xenbus_transaction_end(struct xenbus_transaction t, int abort);
 169
 170/* Single read and scanf: returns -errno or num scanned if > 0. */
 171__scanf(4, 5)
 172int xenbus_scanf(struct xenbus_transaction t,
 173                 const char *dir, const char *node, const char *fmt, ...);
 174
 175/* Read an (optional) unsigned value. */
 176unsigned int xenbus_read_unsigned(const char *dir, const char *node,
 177                                  unsigned int default_val);
 178
 179/* Single printf and write: returns -errno or 0. */
 180__printf(4, 5)
 181int xenbus_printf(struct xenbus_transaction t,
 182                  const char *dir, const char *node, const char *fmt, ...);
 183
 184/* Generic read function: NULL-terminated triples of name,
 185 * sprintf-style type string, and pointer. Returns 0 or errno.*/
 186int xenbus_gather(struct xenbus_transaction t, const char *dir, ...);
 187
 188/* notifer routines for when the xenstore comes up */
 189extern int xenstored_ready;
 190int register_xenstore_notifier(struct notifier_block *nb);
 191void unregister_xenstore_notifier(struct notifier_block *nb);
 192
 193int register_xenbus_watch(struct xenbus_watch *watch);
 194void unregister_xenbus_watch(struct xenbus_watch *watch);
 195void xs_suspend(void);
 196void xs_resume(void);
 197void xs_suspend_cancel(void);
 198
 199struct work_struct;
 200
 201#define XENBUS_IS_ERR_READ(str) ({                      \
 202        if (!IS_ERR(str) && strlen(str) == 0) {         \
 203                kfree(str);                             \
 204                str = ERR_PTR(-ERANGE);                 \
 205        }                                               \
 206        IS_ERR(str);                                    \
 207})
 208
 209#define XENBUS_EXIST_ERR(err) ((err) == -ENOENT || (err) == -ERANGE)
 210
 211int xenbus_watch_path(struct xenbus_device *dev, const char *path,
 212                      struct xenbus_watch *watch,
 213                      bool (*will_handle)(struct xenbus_watch *,
 214                                          const char *, const char *),
 215                      void (*callback)(struct xenbus_watch *,
 216                                       const char *, const char *));
 217__printf(5, 6)
 218int xenbus_watch_pathfmt(struct xenbus_device *dev, struct xenbus_watch *watch,
 219                         bool (*will_handle)(struct xenbus_watch *,
 220                                             const char *, const char *),
 221                         void (*callback)(struct xenbus_watch *,
 222                                          const char *, const char *),
 223                         const char *pathfmt, ...);
 224
 225int xenbus_switch_state(struct xenbus_device *dev, enum xenbus_state new_state);
 226int xenbus_grant_ring(struct xenbus_device *dev, void *vaddr,
 227                      unsigned int nr_pages, grant_ref_t *grefs);
 228int xenbus_map_ring_valloc(struct xenbus_device *dev, grant_ref_t *gnt_refs,
 229                           unsigned int nr_grefs, void **vaddr);
 230
 231int xenbus_unmap_ring_vfree(struct xenbus_device *dev, void *vaddr);
 232
 233int xenbus_alloc_evtchn(struct xenbus_device *dev, evtchn_port_t *port);
 234int xenbus_free_evtchn(struct xenbus_device *dev, evtchn_port_t port);
 235
 236enum xenbus_state xenbus_read_driver_state(const char *path);
 237
 238__printf(3, 4)
 239void xenbus_dev_error(struct xenbus_device *dev, int err, const char *fmt, ...);
 240__printf(3, 4)
 241void xenbus_dev_fatal(struct xenbus_device *dev, int err, const char *fmt, ...);
 242
 243const char *xenbus_strstate(enum xenbus_state state);
 244int xenbus_dev_is_online(struct xenbus_device *dev);
 245int xenbus_frontend_closed(struct xenbus_device *dev);
 246
 247extern const struct file_operations xen_xenbus_fops;
 248extern struct xenstore_domain_interface *xen_store_interface;
 249extern int xen_store_evtchn;
 250
 251#endif /* _XEN_XENBUS_H */
 252