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  1. /*
  2.  * Copyright (C) 2001-2004 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. #include <time/timeout.h>
  30. #include <typedefs.h>
  31. #include <arch/types.h>
  32. #include <config.h>
  33. #include <synch/spinlock.h>
  34. #include <func.h>
  35. #include <cpu.h>
  36. #include <print.h>
  37. #include <arch/asm.h>
  38. #include <arch.h>
  39.  
  40. void timeout_init(void)
  41. {
  42.     spinlock_initialize(&the->cpu->timeoutlock);
  43.     list_initialize(&the->cpu->timeout_active_head);
  44. }
  45.  
  46.  
  47. void timeout_reinitialize(timeout_t *t)
  48. {
  49.     t->cpu = NULL;
  50.     t->ticks = 0;
  51.     t->handler = NULL;
  52.     t->arg = NULL;
  53.     link_initialize(&t->link);
  54. }
  55.  
  56. void timeout_initialize(timeout_t *t)
  57. {
  58.     spinlock_initialize(&t->lock);
  59.     timeout_reinitialize(t);
  60. }
  61.  
  62. /*
  63.  * This function registers f for execution in about time microseconds.
  64.  */
  65. void timeout_register(timeout_t *t, __u64 time, timeout_handler f, void *arg)
  66. {
  67.     timeout_t *hlp;
  68.     link_t *l, *m;
  69.     pri_t pri;
  70.     __u64 sum;
  71.  
  72.     pri = cpu_priority_high();
  73.     spinlock_lock(&the->cpu->timeoutlock);
  74.     spinlock_lock(&t->lock);
  75.    
  76.     if (t->cpu)
  77.         panic("timeout_register: t->cpu != 0");
  78.  
  79.     t->cpu = the->cpu;
  80.     t->ticks = us2ticks(time);
  81.    
  82.     t->handler = f;
  83.     t->arg = arg;
  84.    
  85.     /*
  86.      * Insert t into the active timeouts list according to t->ticks.
  87.      */
  88.     sum = 0;
  89.     l = the->cpu->timeout_active_head.next;
  90.     while (l != &the->cpu->timeout_active_head) {
  91.         hlp = list_get_instance(l, timeout_t, link);
  92.         spinlock_lock(&hlp->lock);
  93.         if (t->ticks < sum + hlp->ticks) {
  94.             spinlock_unlock(&hlp->lock);
  95.             break;
  96.         }
  97.         sum += hlp->ticks;
  98.         spinlock_unlock(&hlp->lock);
  99.         l = l->next;
  100.     }
  101.     m = l->prev;
  102.     list_prepend(&t->link, m); /* avoid using l->prev */
  103.  
  104.     /*
  105.      * Adjust t->ticks according to ticks accumulated in h's predecessors.
  106.      */
  107.     t->ticks -= sum;
  108.  
  109.     /*
  110.      * Decrease ticks of t's immediate succesor by t->ticks.
  111.      */
  112.     if (l != &the->cpu->timeout_active_head) {
  113.         spinlock_lock(&hlp->lock);
  114.         hlp->ticks -= t->ticks;
  115.         spinlock_unlock(&hlp->lock);
  116.     }
  117.  
  118.     spinlock_unlock(&t->lock);
  119.     spinlock_unlock(&the->cpu->timeoutlock);
  120.     cpu_priority_restore(pri);
  121. }
  122.  
  123. int timeout_unregister(timeout_t *t)
  124. {
  125.     timeout_t *hlp;
  126.     link_t *l;
  127.     pri_t pri;
  128.  
  129. grab_locks:
  130.     pri = cpu_priority_high();
  131.     spinlock_lock(&t->lock);
  132.     if (!t->cpu) {
  133.         spinlock_unlock(&t->lock);
  134.         cpu_priority_restore(pri);
  135.         return 0;
  136.     }
  137.     if (!spinlock_trylock(&t->cpu->timeoutlock)) {
  138.         spinlock_unlock(&t->lock);
  139.         cpu_priority_restore(pri);     
  140.         goto grab_locks;
  141.     }
  142.    
  143.     /*
  144.      * Now we know for sure that t hasn't been activated yet
  145.      * and is lurking in t->cpu->timeout_active_head queue.
  146.      */
  147.  
  148.     l = t->link.next;
  149.     if (l != &t->cpu->timeout_active_head) {
  150.         hlp = list_get_instance(l, timeout_t, link);
  151.         spinlock_lock(&hlp->lock);
  152.         hlp->ticks += t->ticks;
  153.         spinlock_unlock(&hlp->lock);
  154.     }
  155.    
  156.     list_remove(&t->link);
  157.     spinlock_unlock(&t->cpu->timeoutlock);
  158.  
  159.     timeout_reinitialize(t);
  160.     spinlock_unlock(&t->lock);
  161.  
  162.     cpu_priority_restore(pri);
  163.     return 1;
  164. }
  165.