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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. #include <ddi/irq.h>
  45.  
  46. #define IRQ_COUNT 8
  47. #define TIMER_IRQ 7
  48.  
  49. function virtual_timer_fnc = NULL;
  50. static irq_t timer_irq;
  51.  
  52. /** Disable interrupts.
  53.  *
  54.  * @return Old interrupt priority level.
  55.  */
  56. ipl_t interrupts_disable(void)
  57. {
  58.     ipl_t ipl = (ipl_t) cp0_status_read();
  59.     cp0_status_write(ipl & ~cp0_status_ie_enabled_bit);
  60.     return ipl;
  61. }
  62.  
  63. /** Enable interrupts.
  64.  *
  65.  * @return Old interrupt priority level.
  66.  */
  67. ipl_t interrupts_enable(void)
  68. {
  69.     ipl_t ipl = (ipl_t) cp0_status_read();
  70.     cp0_status_write(ipl | cp0_status_ie_enabled_bit);
  71.     return ipl;
  72. }
  73.  
  74. /** Restore interrupt priority level.
  75.  *
  76.  * @param ipl Saved interrupt priority level.
  77.  */
  78. void interrupts_restore(ipl_t ipl)
  79. {
  80.     cp0_status_write(cp0_status_read() | (ipl & cp0_status_ie_enabled_bit));
  81. }
  82.  
  83. /** Read interrupt priority level.
  84.  *
  85.  * @return Current interrupt priority level.
  86.  */
  87. ipl_t interrupts_read(void)
  88. {
  89.     return cp0_status_read();
  90. }
  91.  
  92. /* TODO: This is SMP unsafe!!! */
  93. static unsigned long nextcount;
  94. /** Start hardware clock */
  95. static void timer_start(void)
  96. {
  97.     nextcount = cp0_compare_value + cp0_count_read();
  98.     cp0_compare_write(nextcount);
  99. }
  100.  
  101. static irq_ownership_t timer_claim(void)
  102. {
  103.     return IRQ_ACCEPT;
  104. }
  105.  
  106. static void timer_irq_handler(irq_t *irq, void *arg, ...)
  107. {
  108.     unsigned long drift;
  109.  
  110.     drift = cp0_count_read() - nextcount;
  111.     while (drift > cp0_compare_value) {
  112.         drift -= cp0_compare_value;
  113.         CPU->missed_clock_ticks++;
  114.     }
  115.     nextcount = cp0_count_read() + cp0_compare_value - drift;
  116.     cp0_compare_write(nextcount);
  117.     clock();
  118.    
  119.     if (virtual_timer_fnc != NULL)
  120.         virtual_timer_fnc();
  121. }
  122.  
  123. /* Initialize basic tables for exception dispatching */
  124. void interrupt_init(void)
  125. {
  126.     irq_init(IRQ_COUNT, IRQ_COUNT);
  127.    
  128.     irq_initialize(&timer_irq);
  129.     timer_irq.devno = device_assign_devno();
  130.     timer_irq.inr = TIMER_IRQ;
  131.     timer_irq.claim = timer_claim;
  132.     timer_irq.handler = timer_irq_handler;
  133.     irq_register(&timer_irq);
  134.    
  135.     timer_start();
  136.     cp0_unmask_int(TIMER_IRQ);
  137. }
  138.  
  139. /** @}
  140.  */
  141.