kernel/core/its.c

   1 /*
   2  *  ZeX/OS
   3  *  Copyright (C) 2009  Tomas 'ZeXx86' Jedrzejek (zexx86@zexos.org)
   4  *  Copyright (C) 2010  Tomas 'ZeXx86' Jedrzejek (zexx86@zexos.org)
   5  *
   6  *  This program is free software: you can redistribute it and/or modify
   7  *  it under the terms of the GNU General Public License as published by
   8  *  the Free Software Foundation, either version 3 of the License, or
   9  *  (at your option) any later version.
  10  *
  11  *  This program is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *  GNU General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU General Public License
  17  *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 /** Interval Time Scheduler - NOTE: it's not a task/process scheduler */
  21
  22 #include <system.h>
  23 #include <its.h>
  24
  25 its_t its_list;
  26
  27 extern unsigned long timer_ticks;
  28
  29 unsigned int its_unregister (its_t *its)
  30 {
  31         if (!its)
  32                 return 0;
  33
  34         its->next->prev = its->prev;
  35         its->prev->next = its->next;
  36
  37         kfree (its);
  38
  39         return 1;
  40 }
  41
  42 unsigned task_its ()
  43 {
  44         for (;; schedule ()) {
  45                 its_t *its;
  46                 for (its = its_list.next; its != &its_list; its = its->next)
  47                         if ((timer_ticks-its->timer) >= its->interval) {
  48                                 if (!its->handler (its->arg)) {
  49                                         its_unregister (its);
  50                                         break;
  51                                 }
  52
  53                                 its->timer = timer_ticks;
  54                         }
  55         }
  56
  57         return 1;
  58 }
  59
  60 unsigned int its_register (unsigned long interval, its_handler_t *handler, void *arg)
  61 {
  62         its_t *its = its_list.next;
  63         /* create ITS' task when it's really needed */
  64         if (its == &its_list)
  65                 task_create ("its", (unsigned) task_its, 255);
  66
  67         /* alloc and init context */
  68         its = (its_t *) kmalloc (sizeof (its_t));
  69
  70         if (!its)
  71                 return 0;
  72
  73         its->timer = timer_ticks;
  74         its->interval = interval;
  75         its->handler = handler;
  76         its->arg = arg;
  77
  78         /* add into list */
  79         its->next = &its_list;
  80         its->prev = its_list.prev;
  81         its->prev->next = its;
  82         its->next->prev = its;
  83
  84         DPRINT (DBG_CORE, "its_register () -> 0x%x every %dms", handler, interval);
  85
  86         return 1;
  87 }
  88
  89 #ifdef TEST
  90 unsigned int test_its_handler (void *arg)
  91 {
  92         if (arg)
  93                 kprintf ("%s", arg);
  94
  95         return 1;
  96 }
  97 #endif
  98
  99 unsigned int init_its ()
 100 {
 101         its_list.next = &its_list;
 102         its_list.prev = &its_list;
 103
 104 #ifdef TEST
 105         its_register (10000, &test_its_handler, "test");
 106 #endif
 107         return 1;
 108 }