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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. /**
  30.  * @file    timeout.c
  31.  * @brief   Timeout management functions.
  32.  */
  33.  
  34. #include <time/timeout.h>
  35. #include <typedefs.h>
  36. #include <arch/types.h>
  37. #include <config.h>
  38. #include <panic.h>
  39. #include <synch/spinlock.h>
  40. #include <func.h>
  41. #include <cpu.h>
  42. #include <arch/asm.h>
  43. #include <arch.h>
  44.  
  45.  
  46. /** Initialize timeouts
  47.  *
  48.  * Initialize kernel timeouts.
  49.  *
  50.  */
  51. void timeout_init(void)
  52. {
  53.     spinlock_initialize(&CPU->timeoutlock, "timeout_lock");
  54.     list_initialize(&CPU->timeout_active_head);
  55. }
  56.  
  57.  
  58. /** Reinitialize timeout
  59.  *
  60.  * Initialize all members except the lock.
  61.  *
  62.  * @param t Timeout to be initialized.
  63.  *
  64.  */
  65. void timeout_reinitialize(timeout_t *t)
  66. {
  67.     t->cpu = NULL;
  68.     t->ticks = 0;
  69.     t->handler = NULL;
  70.     t->arg = NULL;
  71.     link_initialize(&t->link);
  72. }
  73.  
  74.  
  75. /** Initialize timeout
  76.  *
  77.  * Initialize all members including the lock.
  78.  *
  79.  * @param t Timeout to be initialized.
  80.  *
  81.  */
  82. void timeout_initialize(timeout_t *t)
  83. {
  84.     spinlock_initialize(&t->lock, "timeout_t_lock");
  85.     timeout_reinitialize(t);
  86. }
  87.  
  88.  
  89. /** Register timeout
  90.  *
  91.  * Insert timeout handler f (with argument arg)
  92.  * to timeout list and make it execute in
  93.  * time microseconds (or slightly more).
  94.  *
  95.  * @param t    Timeout structure.
  96.  * @param time Number of usec in the future to execute
  97.  *             the handler.
  98.  * @param f    Timeout handler function.
  99.  * @param arg  Timeout handler argument.
  100.  *
  101.  */
  102. void timeout_register(timeout_t *t, __u64 time, timeout_handler_t f, void *arg)
  103. {
  104.     timeout_t *hlp = NULL;
  105.     link_t *l, *m;
  106.     ipl_t ipl;
  107.     __u64 sum;
  108.  
  109.     ipl = interrupts_disable();
  110.     spinlock_lock(&CPU->timeoutlock);
  111.     spinlock_lock(&t->lock);
  112.  
  113.     if (t->cpu)
  114.         panic("t->cpu != 0");
  115.  
  116.     t->cpu = CPU;
  117.     t->ticks = us2ticks(time);
  118.    
  119.     t->handler = f;
  120.     t->arg = arg;
  121.  
  122.     /*
  123.      * Insert t into the active timeouts list according to t->ticks.
  124.      */
  125.     sum = 0;
  126.     l = CPU->timeout_active_head.next;
  127.     while (l != &CPU->timeout_active_head) {
  128.         hlp = list_get_instance(l, timeout_t, link);
  129.         spinlock_lock(&hlp->lock);
  130.         if (t->ticks < sum + hlp->ticks) {
  131.             spinlock_unlock(&hlp->lock);
  132.             break;
  133.         }
  134.         sum += hlp->ticks;
  135.         spinlock_unlock(&hlp->lock);
  136.         l = l->next;
  137.     }
  138.  
  139.     m = l->prev;
  140.     list_prepend(&t->link, m); /* avoid using l->prev */
  141.  
  142.     /*
  143.      * Adjust t->ticks according to ticks accumulated in h's predecessors.
  144.      */
  145.     t->ticks -= sum;
  146.  
  147.     /*
  148.      * Decrease ticks of t's immediate succesor by t->ticks.
  149.      */
  150.     if (l != &CPU->timeout_active_head) {
  151.         spinlock_lock(&hlp->lock);
  152.         hlp->ticks -= t->ticks;
  153.         spinlock_unlock(&hlp->lock);
  154.     }
  155.  
  156.     spinlock_unlock(&t->lock);
  157.     spinlock_unlock(&CPU->timeoutlock);
  158.     interrupts_restore(ipl);
  159. }
  160.  
  161.  
  162. /** Unregister timeout
  163.  *
  164.  * Remove timeout from timeout list.
  165.  *
  166.  * @param t Timeout to unregister.
  167.  *
  168.  * @return true on success, false on failure.
  169.  */
  170. bool timeout_unregister(timeout_t *t)
  171. {
  172.     timeout_t *hlp;
  173.     link_t *l;
  174.     ipl_t ipl;
  175.  
  176. grab_locks:
  177.     ipl = interrupts_disable();
  178.     spinlock_lock(&t->lock);
  179.     if (!t->cpu) {
  180.         spinlock_unlock(&t->lock);
  181.         interrupts_restore(ipl);
  182.         return false;
  183.     }
  184.     if (!spinlock_trylock(&t->cpu->timeoutlock)) {
  185.         spinlock_unlock(&t->lock);
  186.         interrupts_restore(ipl);       
  187.         goto grab_locks;
  188.     }
  189.    
  190.     /*
  191.      * Now we know for sure that t hasn't been activated yet
  192.      * and is lurking in t->cpu->timeout_active_head queue.
  193.      */
  194.  
  195.     l = t->link.next;
  196.     if (l != &t->cpu->timeout_active_head) {
  197.         hlp = list_get_instance(l, timeout_t, link);
  198.         spinlock_lock(&hlp->lock);
  199.         hlp->ticks += t->ticks;
  200.         spinlock_unlock(&hlp->lock);
  201.     }
  202.    
  203.     list_remove(&t->link);
  204.     spinlock_unlock(&t->cpu->timeoutlock);
  205.  
  206.     timeout_reinitialize(t);
  207.     spinlock_unlock(&t->lock);
  208.  
  209.     interrupts_restore(ipl);
  210.     return true;
  211. }
  212.