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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 0xffffffff00000000LL
  51.  
  52. #define FREQ_DENOMINATOR_SHIFT 0
  53. #define FREQ_DENOMINATOR_MASK 0xffffffffLL
  54.  
  55.  
  56. uint64_t it_delta;
  57.  
  58.  
  59. static irq_t it_irq;
  60.  
  61. static irq_ownership_t it_claim(void);
  62. static void it_interrupt(irq_t *irq, void *arg, ...);
  63.  
  64. /** Initialize Interval Timer. */
  65. void it_init(void)
  66. {
  67.     cr_itv_t itv;
  68.    
  69.     if(config.cpu_active==1)
  70.     {
  71.         irq_initialize(&it_irq);
  72.         it_irq.inr = INTERRUPT_TIMER;
  73.         it_irq.devno = device_assign_devno();
  74.         it_irq.claim = it_claim;
  75.         it_irq.handler = it_interrupt;
  76.         irq_register(&it_irq);
  77.        
  78.         uint64_t base_freq;
  79.         base_freq  = ((bootinfo->freq_scale) & FREQ_NUMERATOR_MASK) >> FREQ_NUMERATOR_SHIFT;
  80.         base_freq *= bootinfo->sys_freq;
  81.         base_freq /= ((bootinfo->freq_scale) & FREQ_DENOMINATOR_MASK) >> FREQ_DENOMINATOR_SHIFT;
  82.        
  83.         it_delta = base_freq /HZ;
  84.        
  85.     }
  86.    
  87.     /* initialize Interval Timer external interrupt vector */
  88.     itv.value = itv_read();
  89.     itv.vector = INTERRUPT_TIMER;
  90.     itv.m = 0;
  91.     itv_write(itv.value);
  92.  
  93.     /* set Interval Timer Counter to zero */
  94.     itc_write(0);
  95.    
  96.     /* generate first Interval Timer interrupt in IT_DELTA ticks */
  97.     itm_write(IT_DELTA);
  98.  
  99.     /* propagate changes */
  100.     srlz_d();
  101. }
  102.  
  103. /** Always claim ownership for this IRQ.
  104.  *
  105.  * Other devices are responsible to avoid using INR 0.
  106.  *
  107.  * @return Always IRQ_ACCEPT.
  108.  */
  109. irq_ownership_t it_claim(void)
  110. {
  111.     return IRQ_ACCEPT;
  112. }
  113.  
  114. /** Process Interval Timer interrupt. */
  115. void it_interrupt(irq_t *irq, void *arg, ...)
  116. {
  117.     int64_t c;
  118.     int64_t m;
  119.    
  120.     eoi_write(EOI);
  121.    
  122.     m = itm_read();
  123.    
  124.     while (1) {
  125.         c = itc_read();
  126.         c += IT_SERVICE_CLOCKS;
  127.  
  128.         m += IT_DELTA;
  129.         if (m - c < 0)
  130.             CPU->missed_clock_ticks++;
  131.         else
  132.             break;
  133.     }
  134.    
  135.     itm_write(m);
  136.     srlz_d();               /* propagate changes */
  137.  
  138.     /*
  139.      * We are holding a lock which prevents preemption.
  140.      * Release the lock, call clock() and reacquire the lock again.
  141.      */
  142.     spinlock_unlock(&irq->lock);   
  143.     clock();
  144.     spinlock_lock(&irq->lock);
  145. }
  146.  
  147. /** @}
  148.  */
  149.