kernel/core/its.c

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