text: /******************************************************************************
   * xenbus.h
   *
   * Talks to Xen Store to figure out what devices we have.
   *
   * Copyright (C) 2005 Rusty Russell, IBM Corporation
   * Copyright (C) 2005 XenSource Ltd.
   *
   * This program is free software; you can redistribute it and/or
   * modify it under the terms of the GNU General Public License version 2
   * as published by the Free Software Foundation; or, when distributed
   * separately from the Linux kernel or incorporated into other
   * software packages, subject to the following license:
   *
   * Permission is hereby granted, free of charge, to any person obtaining a copy
   * of this source file (the "Software"), to deal in the Software without
   * restriction, including without limitation the rights to use, copy, modify,
   * merge, publish, distribute, sublicense, and/or sell copies of the Software,
   * and to permit persons to whom the Software is furnished to do so, subject to
   * the following conditions:
   *
   * The above copyright notice and this permission notice shall be included in
   * all copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
   * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
   * IN THE SOFTWARE.
   */
  
  #ifndef _XEN_XENBUS_H
  #define _XEN_XENBUS_H
  
  #include <linux/device.h>
  #include <linux/notifier.h>
  #include <linux/mutex.h>
  #include <linux/export.h>
  #include <linux/completion.h>
  #include <linux/init.h>
  #include <linux/slab.h>
  #include <xen/interface/xen.h>
  #include <xen/interface/grant_table.h>
  #include <xen/interface/io/xenbus.h>
  #include <xen/interface/io/xs_wire.h>
  
  /* Register callback to watch this node. */
  struct xenbus_watch
  {
  	struct list_head list;
  
  	/* Path being watched. */
  	const char *node;
  
  	/* Callback (executed in a process context with no locks held). */
  	void (*callback)(struct xenbus_watch *,
  			 const char **vec, unsigned int len);
  };
  
  
  /* A xenbus device. */
  struct xenbus_device {
  	const char *devicetype;
  	const char *nodename;
  	const char *otherend;
  	int otherend_id;
  	struct xenbus_watch otherend_watch;
  	struct device dev;
  	enum xenbus_state state;
  	struct completion down;
  	struct work_struct work;
  };
  
  static inline struct xenbus_device *to_xenbus_device(struct device *dev)
  {
  	return container_of(dev, struct xenbus_device, dev);
  }
  
  struct xenbus_device_id
  {
  	/* .../device/<device_type>/<identifier> */
  	char devicetype[32]; 	/* General class of device. */
  };
  
  /* A xenbus driver. */
  struct xenbus_driver {
  	const char *name;       /* defaults to ids[0].devicetype */
  	const struct xenbus_device_id *ids;
  	int (*probe)(struct xenbus_device *dev,
  		     const struct xenbus_device_id *id);
  	void (*otherend_changed)(struct xenbus_device *dev,
  				 enum xenbus_state backend_state);
  	int (*remove)(struct xenbus_device *dev);
  	int (*suspend)(struct xenbus_device *dev);
  	int (*resume)(struct xenbus_device *dev);
  	int (*uevent)(struct xenbus_device *, struct kobj_uevent_env *);
  	struct device_driver driver;
  	int (*read_otherend_details)(struct xenbus_device *dev);
  	int (*is_ready)(struct xenbus_device *dev);
  };
  
  static inline struct xenbus_driver *to_xenbus_driver(struct device_driver *drv)
  {
  	return container_of(drv, struct xenbus_driver, driver);
  }
  
  int __must_check __xenbus_register_frontend(struct xenbus_driver *drv,
  					    struct module *owner,
  					    const char *mod_name);
  int __must_check __xenbus_register_backend(struct xenbus_driver *drv,
  					   struct module *owner,
  					   const char *mod_name);
  
  #define xenbus_register_frontend(drv) \
  	__xenbus_register_frontend(drv, THIS_MODULE, KBUILD_MODNAME);
  #define xenbus_register_backend(drv) \
  	__xenbus_register_backend(drv, THIS_MODULE, KBUILD_MODNAME);
  
  void xenbus_unregister_driver(struct xenbus_driver *drv);
  
  struct xenbus_transaction
  {
  	u32 id;
  };
  
  /* Nil transaction ID. */
  #define XBT_NIL ((struct xenbus_transaction) { 0 })
  
  char **xenbus_directory(struct xenbus_transaction t,
  			const char *dir, const char *node, unsigned int *num);
  void *xenbus_read(struct xenbus_transaction t,
  		  const char *dir, const char *node, unsigned int *len);
  int xenbus_write(struct xenbus_transaction t,
  		 const char *dir, const char *node, const char *string);
  int xenbus_mkdir(struct xenbus_transaction t,
  		 const char *dir, const char *node);
  int xenbus_exists(struct xenbus_transaction t,
  		  const char *dir, const char *node);
  int xenbus_rm(struct xenbus_transaction t, const char *dir, const char *node);
  int xenbus_transaction_start(struct xenbus_transaction *t);
  int xenbus_transaction_end(struct xenbus_transaction t, int abort);
  
  /* Single read and scanf: returns -errno or num scanned if > 0. */
  __scanf(4, 5)
  int xenbus_scanf(struct xenbus_transaction t,
  		 const char *dir, const char *node, const char *fmt, ...);
  
  /* Single printf and write: returns -errno or 0. */
  __printf(4, 5)
  int xenbus_printf(struct xenbus_transaction t,
  		  const char *dir, const char *node, const char *fmt, ...);
  
  /* Generic read function: NULL-terminated triples of name,
   * sprintf-style type string, and pointer. Returns 0 or errno.*/
  int xenbus_gather(struct xenbus_transaction t, const char *dir, ...);
  
  /* notifer routines for when the xenstore comes up */
  extern int xenstored_ready;
  int register_xenstore_notifier(struct notifier_block *nb);
  void unregister_xenstore_notifier(struct notifier_block *nb);
  
  int register_xenbus_watch(struct xenbus_watch *watch);
  void unregister_xenbus_watch(struct xenbus_watch *watch);
  void xs_suspend(void);
  void xs_resume(void);
  void xs_suspend_cancel(void);
  
  /* Used by xenbus_dev to borrow kernel's store connection. */
  void *xenbus_dev_request_and_reply(struct xsd_sockmsg *msg);
  
  struct work_struct;
  
  /* Prepare for domain suspend: then resume or cancel the suspend. */
  void xenbus_suspend(void);
  void xenbus_resume(void);
  void xenbus_probe(struct work_struct *);
  void xenbus_suspend_cancel(void);
  
  #define XENBUS_IS_ERR_READ(str) ({			\
  	if (!IS_ERR(str) && strlen(str) == 0) {		\
  		kfree(str);				\
  		str = ERR_PTR(-ERANGE);			\
  	}						\
  	IS_ERR(str);					\
  })
  
  #define XENBUS_EXIST_ERR(err) ((err) == -ENOENT || (err) == -ERANGE)
  
  int xenbus_watch_path(struct xenbus_device *dev, const char *path,
  		      struct xenbus_watch *watch,
  		      void (*callback)(struct xenbus_watch *,
  				       const char **, unsigned int));
  __printf(4, 5)
  int xenbus_watch_pathfmt(struct xenbus_device *dev, struct xenbus_watch *watch,
  			 void (*callback)(struct xenbus_watch *,
  					  const char **, unsigned int),
  			 const char *pathfmt, ...);
  
  int xenbus_switch_state(struct xenbus_device *dev, enum xenbus_state new_state);
  int xenbus_grant_ring(struct xenbus_device *dev, unsigned long ring_mfn);
  int xenbus_map_ring_valloc(struct xenbus_device *dev,
  			   int gnt_ref, void **vaddr);
  int xenbus_map_ring(struct xenbus_device *dev, int gnt_ref,
  			   grant_handle_t *handle, void *vaddr);
  
  int xenbus_unmap_ring_vfree(struct xenbus_device *dev, void *vaddr);
  int xenbus_unmap_ring(struct xenbus_device *dev,
  		      grant_handle_t handle, void *vaddr);
  
  int xenbus_alloc_evtchn(struct xenbus_device *dev, int *port);
  int xenbus_free_evtchn(struct xenbus_device *dev, int port);
  
  enum xenbus_state xenbus_read_driver_state(const char *path);
  
  __printf(3, 4)
  void xenbus_dev_error(struct xenbus_device *dev, int err, const char *fmt, ...);
  __printf(3, 4)
  void xenbus_dev_fatal(struct xenbus_device *dev, int err, const char *fmt, ...);
  
  const char *xenbus_strstate(enum xenbus_state state);
  int xenbus_dev_is_online(struct xenbus_device *dev);
  int xenbus_frontend_closed(struct xenbus_device *dev);
  
  #endif /* _XEN_XENBUS_H */
  