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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. /** Initialize timeouts
  49.  *
  50.  * Initialize kernel timeouts.
  51.  *
  52.  */
  53. void timeout_init(void)
  54. {
  55.     spinlock_initialize(&CPU->timeoutlock, "timeout_lock");
  56.     list_initialize(&CPU->timeout_active_head);
  57. }
  58.  
  59.  
  60. /** Reinitialize timeout
  61.  *
  62.  * Initialize all members except the lock.
  63.  *
  64.  * @param t     Timeout to be initialized.
  65.  *
  66.  */
  67. void timeout_reinitialize(timeout_t *t)
  68. {
  69.     t->cpu = NULL;
  70.     t->ticks = 0;
  71.     t->handler = NULL;
  72.     t->arg = NULL;
  73.     link_initialize(&t->link);
  74. }
  75.  
  76.  
  77. /** Initialize timeout
  78.  *
  79.  * Initialize all members including the lock.
  80.  *
  81.  * @param t     Timeout to be initialized.
  82.  *
  83.  */
  84. void timeout_initialize(timeout_t *t)
  85. {
  86.     spinlock_initialize(&t->lock, "timeout_t_lock");
  87.     timeout_reinitialize(t);
  88. }
  89.  
  90.  
  91. /** Register timeout
  92.  *
  93.  * Insert timeout handler f (with argument arg)
  94.  * to timeout list and make it execute in
  95.  * time microseconds (or slightly more).
  96.  *
  97.  * @param t     Timeout structure.
  98.  * @param time      Number of usec in the future to execute the handler.
  99.  * @param f     Timeout handler function.
  100.  * @param arg       Timeout handler argument.
  101.  *
  102.  */
  103. void
  104. timeout_register(timeout_t *t, uint64_t time, timeout_handler_t f, void *arg)
  105. {
  106.     timeout_t *hlp = NULL;
  107.     link_t *l, *m;
  108.     ipl_t ipl;
  109.     uint64_t sum;
  110.  
  111.     ipl = interrupts_disable();
  112.     spinlock_lock(&CPU->timeoutlock);
  113.     spinlock_lock(&t->lock);
  114.  
  115.     if (t->cpu)
  116.         panic("t->cpu != 0");
  117.  
  118.     t->cpu = CPU;
  119.     t->ticks = us2ticks(time);
  120.    
  121.     t->handler = f;
  122.     t->arg = arg;
  123.  
  124.     /*
  125.      * Insert t into the active timeouts list according to t->ticks.
  126.      */
  127.     sum = 0;
  128.     l = CPU->timeout_active_head.next;
  129.     while (l != &CPU->timeout_active_head) {
  130.         hlp = list_get_instance(l, timeout_t, link);
  131.         spinlock_lock(&hlp->lock);
  132.         if (t->ticks < sum + hlp->ticks) {
  133.             spinlock_unlock(&hlp->lock);
  134.             break;
  135.         }
  136.         sum += hlp->ticks;
  137.         spinlock_unlock(&hlp->lock);
  138.         l = l->next;
  139.     }
  140.  
  141.     m = l->prev;
  142.     list_prepend(&t->link, m); /* avoid using l->prev */
  143.  
  144.     /*
  145.      * Adjust t->ticks according to ticks accumulated in h's predecessors.
  146.      */
  147.     t->ticks -= sum;
  148.  
  149.     /*
  150.      * Decrease ticks of t's immediate succesor by t->ticks.
  151.      */
  152.     if (l != &CPU->timeout_active_head) {
  153.         spinlock_lock(&hlp->lock);
  154.         hlp->ticks -= t->ticks;
  155.         spinlock_unlock(&hlp->lock);
  156.     }
  157.  
  158.     spinlock_unlock(&t->lock);
  159.     spinlock_unlock(&CPU->timeoutlock);
  160.     interrupts_restore(ipl);
  161. }
  162.  
  163.  
  164. /** Unregister timeout
  165.  *
  166.  * Remove timeout from timeout list.
  167.  *
  168.  * @param t     Timeout to unregister.
  169.  *
  170.  * @return      True on success, false on failure.
  171.  */
  172. bool timeout_unregister(timeout_t *t)
  173. {
  174.     timeout_t *hlp;
  175.     link_t *l;
  176.     ipl_t ipl;
  177.     DEADLOCK_PROBE_INIT(p_tolock);
  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.         DEADLOCK_PROBE(p_tolock, DEADLOCK_THRESHOLD);
  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.