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