firmware/target/arm/pnx0101/timer-pnx0101.c

   1 /***************************************************************************
   2 *             __________               __   ___.
   3 *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
   4 *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
   5 *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
   6 *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
   7 *                     \/            \/     \/    \/            \/
   8 * $Id$
   9 *
  10 * Copyright (C) 2007 Tomasz Malesinski
  11 *
  12 * This program is free software; you can redistribute it and/or
  13 * modify it under the terms of the GNU General Public License
  14 * as published by the Free Software Foundation; either version 2
  15 * of the License, or (at your option) any later version.
  16 *
  17 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  18 * KIND, either express or implied.
  19 *
  20 ****************************************************************************/
  21
  22 #include "system.h"
  23 #include "timer.h"
  24
  25 static long cycles_new = 0;
  26
  27 void TIMER1_ISR(void)
  28 {
  29     if (cycles_new > 0)
  30     {
  31         TIMER1.load = cycles_new - 1;
  32         cycles_new = 0;
  33     }
  34     if (pfn_timer != NULL)
  35     {
  36         cycles_new = -1;
  37         /* "lock" the variable, in case timer_set_period()
  38          * is called within pfn_timer() */
  39         pfn_timer();
  40         cycles_new = 0;
  41     }
  42     TIMER1.clr = 1; /* clear the interrupt */
  43 }
  44
  45 bool timer_set(long cycles, bool start)
  46 {
  47     if (start)
  48     {
  49         if (pfn_unregister != NULL)
  50         {
  51             pfn_unregister();
  52             pfn_unregister = NULL;
  53         }
  54         TIMER1.ctrl &= ~0x80; /* disable the counter */
  55         TIMER1.ctrl |= 0x40;  /* reload after counting down to zero */
  56         TIMER1.ctrl &= ~0xc;  /* no prescaler */
  57         TIMER1.clr = 1;       /* clear an interrupt event */
  58     }
  59     if (start || (cycles_new == -1)) /* within isr, cycles_new is "locked" */
  60     {                                /* enable timer */
  61         TIMER1.load = cycles - 1;
  62         TIMER1.ctrl |= 0x80;        /* enable the counter */
  63     }
  64     else
  65         cycles_new = cycles;
  66
  67     return true;
  68 }
  69
  70 bool timer_start(void)
  71 {
  72     irq_set_int_handler(IRQ_TIMER1, TIMER1_ISR);
  73     irq_enable_int(IRQ_TIMER1);
  74     return true;
  75 }
  76
  77 void timer_stop(void)
  78 {
  79     TIMER1.ctrl &= ~0x80;  /* disable timer 1 */
  80     irq_disable_int(IRQ_TIMER1);
  81 }