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  1. /*
  2.  * Copyright (c) 2006 Jakub Jermar
  3.  * All rights reserved.
  4.  *
  5.  * Redistribution and use in source and binary forms, with or without
  6.  * modification, are permitted provided that the following conditions
  7.  * are met:
  8.  *
  9.  * - Redistributions of source code must retain the above copyright
  10.  *   notice, this list of conditions and the following disclaimer.
  11.  * - Redistributions in binary form must reproduce the above copyright
  12.  *   notice, this list of conditions and the following disclaimer in the
  13.  *   documentation and/or other materials provided with the distribution.
  14.  * - The name of the author may not be used to endorse or promote products
  15.  *   derived from this software without specific prior written permission.
  16.  *
  17.  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  18.  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19.  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20.  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  21.  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22.  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23.  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24.  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25.  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26.  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27.  */
  28.  
  29. /** @addtogroup genarchmm
  30.  * @{
  31.  */
  32.  
  33. /**
  34.  * @file
  35.  * @brief   FIFO queue ASID management.
  36.  *
  37.  * Architectures that link with this file keep the unallocated ASIDs
  38.  * in FIFO queue. The queue can be statically (e.g. mips32) or
  39.  * dynamically allocated (e.g ia64 and sparc64).
  40.  */
  41.  
  42. #include <genarch/mm/asid_fifo.h>
  43. #include <arch/mm/asid.h>
  44. #include <mm/asid.h>
  45. #include <adt/fifo.h>
  46.  
  47. #define FIFO_STATIC_LIMIT   1024
  48. #define FIFO_STATIC     (ASIDS_ALLOCABLE<FIFO_STATIC_LIMIT)
  49.  
  50. /**
  51.  * FIFO queue containing unassigned ASIDs.
  52.  * Can be only accessed when asidlock is held.
  53.  */
  54. #if FIFO_STATIC
  55. FIFO_INITIALIZE_STATIC(free_asids, asid_t, ASIDS_ALLOCABLE);
  56. #else
  57. FIFO_INITIALIZE_DYNAMIC(free_asids, asid_t, ASIDS_ALLOCABLE);
  58. #endif
  59.  
  60. /** Initialize data structures for O(1) ASID allocation and deallocation. */
  61. void asid_fifo_init(void)
  62. {
  63.     int i;
  64.  
  65. #if (!FIFO_STATIC)
  66.     fifo_create(free_asids);
  67. #endif
  68.        
  69.     for (i = 0; i < ASIDS_ALLOCABLE; i++) {
  70.         fifo_push(free_asids, ASID_START + i);
  71.     }
  72. }
  73.  
  74. /** Allocate free ASID.
  75.  *
  76.  * Allocation runs in O(1).
  77.  *
  78.  * @return Free ASID.
  79.  */
  80. asid_t asid_find_free(void)
  81. {
  82.     return fifo_pop(free_asids);
  83. }
  84.  
  85. /** Return ASID among free ASIDs.
  86.  *
  87.  * This operation runs in O(1).
  88.  *
  89.  * @param asid ASID being freed.
  90.  */
  91. void asid_put_arch(asid_t asid)
  92. {
  93.     fifo_push(free_asids, asid);
  94. }
  95.  
  96. /** @}
  97.  */
  98.