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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 generic   
  30.  * @{
  31.  */
  32.  
  33. /**
  34.  * @file
  35.  * @brief   Timeout management functions.
  36.  */
  37.  
  38. #include <time/timeout.h>
  39. #include <typedefs.h>
  40. #include <arch/types.h>
  41. #include <config.h>
  42. #include <panic.h>
  43. #include <synch/spinlock.h>
  44. #include <func.h>
  45. #include <cpu.h>
  46. #include <arch/asm.h>
  47. #include <arch.h>
  48.  
  49.  
  50. /** Initialize timeouts
  51.  *
  52.  * Initialize kernel timeouts.
  53.  *
  54.  */
  55. void timeout_init(void)
  56. {
  57.     spinlock_initialize(&CPU->timeoutlock, "timeout_lock");
  58.     list_initialize(&CPU->timeout_active_head);
  59. }
  60.  
  61.  
  62. /** Reinitialize timeout
  63.  *
  64.  * Initialize all members except the lock.
  65.  *
  66.  * @param t Timeout to be initialized.
  67.  *
  68.  */
  69. void timeout_reinitialize(timeout_t *t)
  70. {
  71.     t->cpu = NULL;
  72.     t->ticks = 0;
  73.     t->handler = NULL;
  74.     t->arg = NULL;
  75.     link_initialize(&t->link);
  76. }
  77.  
  78.  
  79. /** Initialize timeout
  80.  *
  81.  * Initialize all members including the lock.
  82.  *
  83.  * @param t Timeout to be initialized.
  84.  *
  85.  */
  86. void timeout_initialize(timeout_t *t)
  87. {
  88.     spinlock_initialize(&t->lock, "timeout_t_lock");
  89.     timeout_reinitialize(t);
  90. }
  91.  
  92.  
  93. /** Register timeout
  94.  *
  95.  * Insert timeout handler f (with argument arg)
  96.  * to timeout list and make it execute in
  97.  * time microseconds (or slightly more).
  98.  *
  99.  * @param t    Timeout structure.
  100.  * @param time Number of usec in the future to execute
  101.  *             the handler.
  102.  * @param f    Timeout handler function.
  103.  * @param arg  Timeout handler argument.
  104.  *
  105.  */
  106. void timeout_register(timeout_t *t, __u64 time, timeout_handler_t f, void *arg)
  107. {
  108.     timeout_t *hlp = NULL;
  109.     link_t *l, *m;
  110.     ipl_t ipl;
  111.     __u64 sum;
  112.  
  113.     ipl = interrupts_disable();
  114.     spinlock_lock(&CPU->timeoutlock);
  115.     spinlock_lock(&t->lock);
  116.  
  117.     if (t->cpu)
  118.         panic("t->cpu != 0");
  119.  
  120.     t->cpu = CPU;
  121.     t->ticks = us2ticks(time);
  122.    
  123.     t->handler = f;
  124.     t->arg = arg;
  125.  
  126.     /*
  127.      * Insert t into the active timeouts list according to t->ticks.
  128.      */
  129.     sum = 0;
  130.     l = CPU->timeout_active_head.next;
  131.     while (l != &CPU->timeout_active_head) {
  132.         hlp = list_get_instance(l, timeout_t, link);
  133.         spinlock_lock(&hlp->lock);
  134.         if (t->ticks < sum + hlp->ticks) {
  135.             spinlock_unlock(&hlp->lock);
  136.             break;
  137.         }
  138.         sum += hlp->ticks;
  139.         spinlock_unlock(&hlp->lock);
  140.         l = l->next;
  141.     }
  142.  
  143.     m = l->prev;
  144.     list_prepend(&t->link, m); /* avoid using l->prev */
  145.  
  146.     /*
  147.      * Adjust t->ticks according to ticks accumulated in h's predecessors.
  148.      */
  149.     t->ticks -= sum;
  150.  
  151.     /*
  152.      * Decrease ticks of t's immediate succesor by t->ticks.
  153.      */
  154.     if (l != &CPU->timeout_active_head) {
  155.         spinlock_lock(&hlp->lock);
  156.         hlp->ticks -= t->ticks;
  157.         spinlock_unlock(&hlp->lock);
  158.     }
  159.  
  160.     spinlock_unlock(&t->lock);
  161.     spinlock_unlock(&CPU->timeoutlock);
  162.     interrupts_restore(ipl);
  163. }
  164.  
  165.  
  166. /** Unregister timeout
  167.  *
  168.  * Remove timeout from timeout list.
  169.  *
  170.  * @param t Timeout to unregister.
  171.  *
  172.  * @return true on success, false on failure.
  173.  */
  174. bool timeout_unregister(timeout_t *t)
  175. {
  176.     timeout_t *hlp;
  177.     link_t *l;
  178.     ipl_t ipl;
  179.  
  180. grab_locks:
  181.     ipl = interrupts_disable();
  182.     spinlock_lock(&t->lock);
  183.     if (!t->cpu) {
  184.         spinlock_unlock(&t->lock);
  185.         interrupts_restore(ipl);
  186.         return false;
  187.     }
  188.     if (!spinlock_trylock(&t->cpu->timeoutlock)) {
  189.         spinlock_unlock(&t->lock);
  190.         interrupts_restore(ipl);       
  191.         goto grab_locks;
  192.     }
  193.    
  194.     /*
  195.      * Now we know for sure that t hasn't been activated yet
  196.      * and is lurking in t->cpu->timeout_active_head queue.
  197.      */
  198.  
  199.     l = t->link.next;
  200.     if (l != &t->cpu->timeout_active_head) {
  201.         hlp = list_get_instance(l, timeout_t, link);
  202.         spinlock_lock(&hlp->lock);
  203.         hlp->ticks += t->ticks;
  204.         spinlock_unlock(&hlp->lock);
  205.     }
  206.    
  207.     list_remove(&t->link);
  208.     spinlock_unlock(&t->cpu->timeoutlock);
  209.  
  210.     timeout_reinitialize(t);
  211.     spinlock_unlock(&t->lock);
  212.  
  213.     interrupts_restore(ipl);
  214.     return true;
  215. }
  216.  
  217.  /** @}
  218.  */
  219.  
  220.