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  1. /*
  2.  * Copyright (c) 2003-2004 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 mips32interrupt
  30.  * @{
  31.  */
  32. /** @file
  33.  */
  34.  
  35. #include <interrupt.h>
  36. #include <arch/interrupt.h>
  37. #include <arch/types.h>
  38. #include <arch.h>
  39. #include <arch/cp0.h>
  40. #include <time/clock.h>
  41. #include <arch/drivers/arc.h>
  42. #include <ipc/sysipc.h>
  43. #include <ddi/device.h>
  44.  
  45. #define IRQ_COUNT 8
  46. #define TIMER_IRQ 7
  47.  
  48. function virtual_timer_fnc = NULL;
  49. static irq_t timer_irq;
  50.  
  51. /** Disable interrupts.
  52.  *
  53.  * @return Old interrupt priority level.
  54.  */
  55. ipl_t interrupts_disable(void)
  56. {
  57.     ipl_t ipl = (ipl_t) cp0_status_read();
  58.     cp0_status_write(ipl & ~cp0_status_ie_enabled_bit);
  59.     return ipl;
  60. }
  61.  
  62. /** Enable interrupts.
  63.  *
  64.  * @return Old interrupt priority level.
  65.  */
  66. ipl_t interrupts_enable(void)
  67. {
  68.     ipl_t ipl = (ipl_t) cp0_status_read();
  69.     cp0_status_write(ipl | cp0_status_ie_enabled_bit);
  70.     return ipl;
  71. }
  72.  
  73. /** Restore interrupt priority level.
  74.  *
  75.  * @param ipl Saved interrupt priority level.
  76.  */
  77. void interrupts_restore(ipl_t ipl)
  78. {
  79.     cp0_status_write(cp0_status_read() | (ipl & cp0_status_ie_enabled_bit));
  80. }
  81.  
  82. /** Read interrupt priority level.
  83.  *
  84.  * @return Current interrupt priority level.
  85.  */
  86. ipl_t interrupts_read(void)
  87. {
  88.     return cp0_status_read();
  89. }
  90.  
  91. /* TODO: This is SMP unsafe!!! */
  92. static unsigned long nextcount;
  93. /** Start hardware clock */
  94. static void timer_start(void)
  95. {
  96.     nextcount = cp0_compare_value + cp0_count_read();
  97.     cp0_compare_write(nextcount);
  98. }
  99.  
  100. static irq_ownership_t timer_claim(void)
  101. {
  102.     return IRQ_ACCEPT;
  103. }
  104.  
  105. static void timer_irq_handler(irq_t *irq, void *arg, ...)
  106. {
  107.     unsigned long drift;
  108.  
  109.     drift = cp0_count_read() - nextcount;
  110.     while (drift > cp0_compare_value) {
  111.         drift -= cp0_compare_value;
  112.         CPU->missed_clock_ticks++;
  113.     }
  114.     nextcount = cp0_count_read() + cp0_compare_value - drift;
  115.     cp0_compare_write(nextcount);
  116.  
  117.     /*
  118.      * We are holding a lock which prevents preemption.
  119.      * Release the lock, call clock() and reacquire the lock again.
  120.      */
  121.     spinlock_unlock(&irq->lock);
  122.     clock();
  123.     spinlock_lock(&irq->lock);
  124.    
  125.     if (virtual_timer_fnc != NULL)
  126.         virtual_timer_fnc();
  127. }
  128.  
  129. /* Initialize basic tables for exception dispatching */
  130. void interrupt_init(void)
  131. {
  132.     irq_init(IRQ_COUNT, IRQ_COUNT);
  133.    
  134.     irq_initialize(&timer_irq);
  135.     timer_irq.devno = device_assign_devno();
  136.     timer_irq.inr = TIMER_IRQ;
  137.     timer_irq.claim = timer_claim;
  138.     timer_irq.handler = timer_irq_handler;
  139.     irq_register(&timer_irq);
  140.    
  141.     timer_start();
  142.     cp0_unmask_int(TIMER_IRQ);
  143. }
  144.  
  145. /** @}
  146.  */
  147.