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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. /** Interval Timer driver. */
  30.  
  31. #include <arch/drivers/it.h>
  32. #include <arch/interrupt.h>
  33. #include <arch/register.h>
  34. #include <arch/asm.h>
  35. #include <arch/barrier.h>
  36. #include <time/clock.h>
  37.  
  38. /** Initialize Interval Timer. */
  39. void it_init(void)
  40. {
  41.     cr_itv_t itv;
  42.  
  43.     /* initialize Interval Timer external interrupt vector */
  44.     itv.value = itv_read();
  45.     itv.vector = INTERRUPT_TIMER;
  46.     itv.m = 0;
  47.     itv_write(itv.value);
  48.  
  49.     /* set Interval Timer Counter to zero */
  50.     itc_write(0);
  51.    
  52.     /* generate first Interval Timer interrupt in IT_DELTA ticks */
  53.     itm_write(IT_DELTA);
  54.  
  55.     /* propagate changes */
  56.     srlz_d();
  57. }
  58.  
  59. /** Process Interval Timer interrupt. */
  60. void it_interrupt(void)
  61. {
  62.     eoi_write(EOI);
  63.     itm_write(itc_read() + IT_DELTA);   /* program next interruption */
  64.     srlz_d();               /* propagate changes */
  65.     clock();
  66. }
  67.