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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/interrupt.h>
  39. #include <arch/register.h>
  40. #include <arch/asm.h>
  41. #include <arch/barrier.h>
  42. #include <time/clock.h>
  43. #include <ddi/irq.h>
  44. #include <ddi/device.h>
  45. #include <arch.h>
  46.  
  47. #define IT_SERVICE_CLOCKS   64
  48.  
  49. #define FREQ_NUMERATOR_SHIFT    32
  50. #define FREQ_NUMERATOR_MASK 0xffffffff00000000ULL
  51.  
  52. #define FREQ_DENOMINATOR_SHIFT  0
  53. #define FREQ_DENOMINATOR_MASK   0xffffffffULL
  54.  
  55. uint64_t it_delta;
  56.  
  57. static irq_t it_irq;
  58.  
  59. static irq_ownership_t it_claim(irq_t *);
  60. static void it_interrupt(irq_t *);
  61.  
  62. /** Initialize Interval Timer. */
  63. void it_init(void)
  64. {
  65.     cr_itv_t itv;
  66.    
  67.     if (config.cpu_active == 1) {
  68.         irq_initialize(&it_irq);
  69.         it_irq.inr = INTERRUPT_TIMER;
  70.         it_irq.devno = device_assign_devno();
  71.         it_irq.claim = it_claim;
  72.         it_irq.handler = it_interrupt;
  73.         irq_register(&it_irq);
  74.        
  75.         uint64_t base_freq;
  76.         base_freq  = ((bootinfo->freq_scale) & FREQ_NUMERATOR_MASK) >>
  77.             FREQ_NUMERATOR_SHIFT;
  78.         base_freq *= bootinfo->sys_freq;
  79.         base_freq /= ((bootinfo->freq_scale) & FREQ_DENOMINATOR_MASK) >>
  80.             FREQ_DENOMINATOR_SHIFT;
  81.        
  82.         it_delta = base_freq / HZ;
  83.     }
  84.    
  85.     /* initialize Interval Timer external interrupt vector */
  86.     itv.value = itv_read();
  87.     itv.vector = INTERRUPT_TIMER;
  88.     itv.m = 0;
  89.     itv_write(itv.value);
  90.  
  91.     /* set Interval Timer Counter to zero */
  92.     itc_write(0);
  93.    
  94.     /* generate first Interval Timer interrupt in IT_DELTA ticks */
  95.     itm_write(IT_DELTA);
  96.  
  97.     /* propagate changes */
  98.     srlz_d();
  99. }
  100.  
  101. /** Always claim ownership for this IRQ.
  102.  *
  103.  * Other devices are responsible to avoid using INR 0.
  104.  *
  105.  * @return Always IRQ_ACCEPT.
  106.  */
  107. irq_ownership_t it_claim(irq_t *irq)
  108. {
  109.     return IRQ_ACCEPT;
  110. }
  111.  
  112. /** Process Interval Timer interrupt. */
  113. void it_interrupt(irq_t *irq)
  114. {
  115.     int64_t c;
  116.     int64_t m;
  117.    
  118.     eoi_write(EOI);
  119.    
  120.     m = itm_read();
  121.    
  122.     while (1) {
  123.         c = itc_read();
  124.         c += IT_SERVICE_CLOCKS;
  125.  
  126.         m += IT_DELTA;
  127.         if (m - c < 0)
  128.             CPU->missed_clock_ticks++;
  129.         else
  130.             break;
  131.     }
  132.    
  133.     itm_write(m);
  134.     srlz_d();               /* propagate changes */
  135.  
  136.     /*
  137.      * We are holding a lock which prevents preemption.
  138.      * Release the lock, call clock() and reacquire the lock again.
  139.      */
  140.     spinlock_unlock(&irq->lock);   
  141.     clock();
  142.     spinlock_lock(&irq->lock);
  143. }
  144.  
  145. /** @}
  146.  */
  147.