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  1. /*
  2.  * Copyright (C) 2005 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 ia64   
  30.  * @{
  31.  */
  32. /** @file
  33.  */
  34.  
  35. /** Interval Timer driver. */
  36.  
  37. #include <arch/drivers/it.h>
  38. #include <arch/ski/ski.h>
  39. #include <arch/interrupt.h>
  40. #include <arch/register.h>
  41. #include <arch/asm.h>
  42. #include <arch/barrier.h>
  43. #include <time/clock.h>
  44. #include <arch.h>
  45.  
  46.  
  47. #define IT_SERVICE_CLOCKS 64
  48.  
  49. /** Initialize Interval Timer. */
  50. void it_init(void)
  51. {
  52.     cr_itv_t itv;
  53.  
  54.     /* initialize Interval Timer external interrupt vector */
  55.     itv.value = itv_read();
  56.     itv.vector = INTERRUPT_TIMER;
  57.     itv.m = 0;
  58.     itv_write(itv.value);
  59.  
  60.     /* set Interval Timer Counter to zero */
  61.     itc_write(0);
  62.    
  63.     /* generate first Interval Timer interrupt in IT_DELTA ticks */
  64.     itm_write(IT_DELTA);
  65.  
  66.     /* propagate changes */
  67.     srlz_d();
  68. }
  69.  
  70.  
  71. /** Process Interval Timer interrupt. */
  72. void it_interrupt(void)
  73. {
  74.     int64_t c;
  75.     int64_t m;
  76.    
  77.     eoi_write(EOI);
  78.    
  79.     m = itm_read();
  80.    
  81.     while (1) {
  82.         c = itc_read();
  83.         c += IT_SERVICE_CLOCKS;
  84.  
  85.         m += IT_DELTA;
  86.         if (m-c<0)
  87.             CPU->missed_clock_ticks++;
  88.         else
  89.             break;
  90.     }
  91.    
  92.     itm_write(m);
  93.     srlz_d();               /* propagate changes */
  94.    
  95.     clock();
  96.     poll_keyboard();
  97. }
  98.  
  99. /** @}
  100.  */
  101.