/******************************************************************************
   * grant_table.h
   *
   * Two sets of functionality:
   * 1. Granting foreign access to our memory reservation.
   * 2. Accessing others' memory reservations via grant references.
   * (i.e., mechanisms for both sender and recipient of grant references)
   *
   * Copyright (c) 2004-2005, K A Fraser
   * Copyright (c) 2005, Christopher Clark
   *
   * 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 __ASM_GNTTAB_H__
  #define __ASM_GNTTAB_H__
  
  #include <asm/xen/hypervisor.h>
  #include <xen/interface/grant_table.h>
  
  /* NR_GRANT_FRAMES must be less than or equal to that configured in Xen */
  #define NR_GRANT_FRAMES 4
  
  struct gnttab_free_callback {
  	struct gnttab_free_callback *next;
  	void (*fn)(void *);
  	void *arg;
  	u16 count;
  };
  
  int gnttab_grant_foreign_access(domid_t domid, unsigned long frame,
  				int readonly);
  
  /*
   * End access through the given grant reference, iff the grant entry is no
   * longer in use.  Return 1 if the grant entry was freed, 0 if it is still in
   * use.
   */
  int gnttab_end_foreign_access_ref(grant_ref_t ref, int readonly);
  
  /*
   * Eventually end access through the given grant reference, and once that
   * access has been ended, free the given page too.  Access will be ended
   * immediately iff the grant entry is not in use, otherwise it will happen
   * some time later.  page may be 0, in which case no freeing will occur.
   */
  void gnttab_end_foreign_access(grant_ref_t ref, int readonly,
  			       unsigned long page);
  
  int gnttab_grant_foreign_transfer(domid_t domid, unsigned long pfn);
  
  unsigned long gnttab_end_foreign_transfer_ref(grant_ref_t ref);
  unsigned long gnttab_end_foreign_transfer(grant_ref_t ref);
  
  int gnttab_query_foreign_access(grant_ref_t ref);
  
  /*
   * operations on reserved batches of grant references
   */
  int gnttab_alloc_grant_references(u16 count, grant_ref_t *pprivate_head);
  
  void gnttab_free_grant_reference(grant_ref_t ref);
  
  void gnttab_free_grant_references(grant_ref_t head);
  
  int gnttab_empty_grant_references(const grant_ref_t *pprivate_head);
  
  int gnttab_claim_grant_reference(grant_ref_t *pprivate_head);
  
  void gnttab_release_grant_reference(grant_ref_t *private_head,
  				    grant_ref_t release);
  
  void gnttab_request_free_callback(struct gnttab_free_callback *callback,
  				  void (*fn)(void *), void *arg, u16 count);
  void gnttab_cancel_free_callback(struct gnttab_free_callback *callback);
  
  void gnttab_grant_foreign_access_ref(grant_ref_t ref, domid_t domid,
  				     unsigned long frame, int readonly);
  
  void gnttab_grant_foreign_transfer_ref(grant_ref_t, domid_t domid,
  				       unsigned long pfn);
  
  #define gnttab_map_vaddr(map) ((void *)(map.host_virt_addr))
  
  #endif /* __ASM_GNTTAB_H__ */