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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. /** @addtogroup time
  30.  * @{
  31.  */
  32.  
  33. /**
  34.  * @file
  35.  * @brief   Timeout management functions.
  36.  */
  37.  
  38. #include <time/timeout.h>
  39. #include <arch/types.h>
  40. #include <config.h>
  41. #include <panic.h>
  42. #include <synch/spinlock.h>
  43. #include <func.h>
  44. #include <cpu.h>
  45. #include <arch/asm.h>
  46. #include <arch.h>
  47.  
  48.  
  49. /** Initialize timeouts
  50.  *
  51.  * Initialize kernel timeouts.
  52.  *
  53.  */
  54. void timeout_init(void)
  55. {
  56.     spinlock_initialize(&CPU->timeoutlock, "timeout_lock");
  57.     list_initialize(&CPU->timeout_active_head);
  58. }
  59.  
  60.  
  61. /** Reinitialize timeout
  62.  *
  63.  * Initialize all members except the lock.
  64.  *
  65.  * @param t Timeout to be initialized.
  66.  *
  67.  */
  68. void timeout_reinitialize(timeout_t *t)
  69. {
  70.     t->cpu = NULL;
  71.     t->ticks = 0;
  72.     t->handler = NULL;
  73.     t->arg = NULL;
  74.     link_initialize(&t->link);
  75. }
  76.  
  77.  
  78. /** Initialize timeout
  79.  *
  80.  * Initialize all members including the lock.
  81.  *
  82.  * @param t Timeout to be initialized.
  83.  *
  84.  */
  85. void timeout_initialize(timeout_t *t)
  86. {
  87.     spinlock_initialize(&t->lock, "timeout_t_lock");
  88.     timeout_reinitialize(t);
  89. }
  90.  
  91.  
  92. /** Register timeout
  93.  *
  94.  * Insert timeout handler f (with argument arg)
  95.  * to timeout list and make it execute in
  96.  * time microseconds (or slightly more).
  97.  *
  98.  * @param t    Timeout structure.
  99.  * @param time Number of usec in the future to execute
  100.  *             the handler.
  101.  * @param f    Timeout handler function.
  102.  * @param arg  Timeout handler argument.
  103.  *
  104.  */
  105. void timeout_register(timeout_t *t, uint64_t time, timeout_handler_t f, void *arg)
  106. {
  107.     timeout_t *hlp = NULL;
  108.     link_t *l, *m;
  109.     ipl_t ipl;
  110.     uint64_t sum;
  111.  
  112.     ipl = interrupts_disable();
  113.     spinlock_lock(&CPU->timeoutlock);
  114.     spinlock_lock(&t->lock);
  115.  
  116.     if (t->cpu)
  117.         panic("t->cpu != 0");
  118.  
  119.     t->cpu = CPU;
  120.     t->ticks = us2ticks(time);
  121.    
  122.     t->handler = f;
  123.     t->arg = arg;
  124.  
  125.     /*
  126.      * Insert t into the active timeouts list according to t->ticks.
  127.      */
  128.     sum = 0;
  129.     l = CPU->timeout_active_head.next;
  130.     while (l != &CPU->timeout_active_head) {
  131.         hlp = list_get_instance(l, timeout_t, link);
  132.         spinlock_lock(&hlp->lock);
  133.         if (t->ticks < sum + hlp->ticks) {
  134.             spinlock_unlock(&hlp->lock);
  135.             break;
  136.         }
  137.         sum += hlp->ticks;
  138.         spinlock_unlock(&hlp->lock);
  139.         l = l->next;
  140.     }
  141.  
  142.     m = l->prev;
  143.     list_prepend(&t->link, m); /* avoid using l->prev */
  144.  
  145.     /*
  146.      * Adjust t->ticks according to ticks accumulated in h's predecessors.
  147.      */
  148.     t->ticks -= sum;
  149.  
  150.     /*
  151.      * Decrease ticks of t's immediate succesor by t->ticks.
  152.      */
  153.     if (l != &CPU->timeout_active_head) {
  154.         spinlock_lock(&hlp->lock);
  155.         hlp->ticks -= t->ticks;
  156.         spinlock_unlock(&hlp->lock);
  157.     }
  158.  
  159.     spinlock_unlock(&t->lock);
  160.     spinlock_unlock(&CPU->timeoutlock);
  161.     interrupts_restore(ipl);
  162. }
  163.  
  164.  
  165. /** Unregister timeout
  166.  *
  167.  * Remove timeout from timeout list.
  168.  *
  169.  * @param t Timeout to unregister.
  170.  *
  171.  * @return true on success, false on failure.
  172.  */
  173. bool timeout_unregister(timeout_t *t)
  174. {
  175.     timeout_t *hlp;
  176.     link_t *l;
  177.     ipl_t ipl;
  178.  
  179. grab_locks:
  180.     ipl = interrupts_disable();
  181.     spinlock_lock(&t->lock);
  182.     if (!t->cpu) {
  183.         spinlock_unlock(&t->lock);
  184.         interrupts_restore(ipl);
  185.         return false;
  186.     }
  187.     if (!spinlock_trylock(&t->cpu->timeoutlock)) {
  188.         spinlock_unlock(&t->lock);
  189.         interrupts_restore(ipl);       
  190.         goto grab_locks;
  191.     }
  192.    
  193.     /*
  194.      * Now we know for sure that t hasn't been activated yet
  195.      * and is lurking in t->cpu->timeout_active_head queue.
  196.      */
  197.  
  198.     l = t->link.next;
  199.     if (l != &t->cpu->timeout_active_head) {
  200.         hlp = list_get_instance(l, timeout_t, link);
  201.         spinlock_lock(&hlp->lock);
  202.         hlp->ticks += t->ticks;
  203.         spinlock_unlock(&hlp->lock);
  204.     }
  205.    
  206.     list_remove(&t->link);
  207.     spinlock_unlock(&t->cpu->timeoutlock);
  208.  
  209.     timeout_reinitialize(t);
  210.     spinlock_unlock(&t->lock);
  211.  
  212.     interrupts_restore(ipl);
  213.     return true;
  214. }
  215.  
  216. /** @}
  217.  */
  218.