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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 <panic.h>
  34. #include <synch/spinlock.h>
  35. #include <func.h>
  36. #include <cpu.h>
  37. #include <print.h>
  38. #include <arch/asm.h>
  39. #include <arch.h>
  40.  
  41. void timeout_init(void)
  42. {
  43.     spinlock_initialize(&CPU->timeoutlock);
  44.     list_initialize(&CPU->timeout_active_head);
  45. }
  46.  
  47.  
  48. void timeout_reinitialize(timeout_t *t)
  49. {
  50.     t->cpu = NULL;
  51.     t->ticks = 0;
  52.     t->handler = NULL;
  53.     t->arg = NULL;
  54.     link_initialize(&t->link);
  55. }
  56.  
  57. void timeout_initialize(timeout_t *t)
  58. {
  59.     spinlock_initialize(&t->lock);
  60.     timeout_reinitialize(t);
  61. }
  62.  
  63. /*
  64.  * This function registers f for execution in about time microseconds.
  65.  */
  66. void timeout_register(timeout_t *t, __u64 time, timeout_handler f, void *arg)
  67. {
  68.     timeout_t *hlp;
  69.     link_t *l, *m;
  70.     pri_t pri;
  71.     __u64 sum;
  72.  
  73.     pri = cpu_priority_high();
  74.     spinlock_lock(&CPU->timeoutlock);
  75.     spinlock_lock(&t->lock);
  76.    
  77.     if (t->cpu)
  78.         panic("timeout_register: t->cpu != 0");
  79.  
  80.     t->cpu = CPU;
  81.     t->ticks = us2ticks(time);
  82.    
  83.     t->handler = f;
  84.     t->arg = arg;
  85.    
  86.     /*
  87.      * Insert t into the active timeouts list according to t->ticks.
  88.      */
  89.     sum = 0;
  90.     l = CPU->timeout_active_head.next;
  91.     while (l != &CPU->timeout_active_head) {
  92.         hlp = list_get_instance(l, timeout_t, link);
  93.         spinlock_lock(&hlp->lock);
  94.         if (t->ticks < sum + hlp->ticks) {
  95.             spinlock_unlock(&hlp->lock);
  96.             break;
  97.         }
  98.         sum += hlp->ticks;
  99.         spinlock_unlock(&hlp->lock);
  100.         l = l->next;
  101.     }
  102.     m = l->prev;
  103.     list_prepend(&t->link, m); /* avoid using l->prev */
  104.  
  105.     /*
  106.      * Adjust t->ticks according to ticks accumulated in h's predecessors.
  107.      */
  108.     t->ticks -= sum;
  109.  
  110.     /*
  111.      * Decrease ticks of t's immediate succesor by t->ticks.
  112.      */
  113.     if (l != &CPU->timeout_active_head) {
  114.         spinlock_lock(&hlp->lock);
  115.         hlp->ticks -= t->ticks;
  116.         spinlock_unlock(&hlp->lock);
  117.     }
  118.  
  119.     spinlock_unlock(&t->lock);
  120.     spinlock_unlock(&CPU->timeoutlock);
  121.     cpu_priority_restore(pri);
  122. }
  123.  
  124. int timeout_unregister(timeout_t *t)
  125. {
  126.     timeout_t *hlp;
  127.     link_t *l;
  128.     pri_t pri;
  129.  
  130. grab_locks:
  131.     pri = cpu_priority_high();
  132.     spinlock_lock(&t->lock);
  133.     if (!t->cpu) {
  134.         spinlock_unlock(&t->lock);
  135.         cpu_priority_restore(pri);
  136.         return 0;
  137.     }
  138.     if (!spinlock_trylock(&t->cpu->timeoutlock)) {
  139.         spinlock_unlock(&t->lock);
  140.         cpu_priority_restore(pri);     
  141.         goto grab_locks;
  142.     }
  143.    
  144.     /*
  145.      * Now we know for sure that t hasn't been activated yet
  146.      * and is lurking in t->cpu->timeout_active_head queue.
  147.      */
  148.  
  149.     l = t->link.next;
  150.     if (l != &t->cpu->timeout_active_head) {
  151.         hlp = list_get_instance(l, timeout_t, link);
  152.         spinlock_lock(&hlp->lock);
  153.         hlp->ticks += t->ticks;
  154.         spinlock_unlock(&hlp->lock);
  155.     }
  156.    
  157.     list_remove(&t->link);
  158.     spinlock_unlock(&t->cpu->timeoutlock);
  159.  
  160.     timeout_reinitialize(t);
  161.     spinlock_unlock(&t->lock);
  162.  
  163.     cpu_priority_restore(pri);
  164.     return 1;
  165. }
  166.