firmware/target/arm/as3525/kernel-as3525.c

   1 /***************************************************************************
   2  *             __________               __   ___.
   3  *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
   4  *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
   5  *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
   6  *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
   7  *                     \/            \/     \/    \/            \/
   8  * $Id$
   9  *
  10  * Copyright © 2008 Rafaël Carré
  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 #include "config.h"
  22 #include "system.h"
  23 #include "kernel.h"
  24 #include "panic.h"
  25 #include "timer-target.h"
  26
  27 #ifdef HAVE_SCROLLWHEEL
  28 #include "button-target.h"
  29 /* The scrollwheel is polled every 5 ms (the tick tasks only every 10) */
  30 static volatile int poll_scrollwheel = 0;
  31
  32 void INT_TIMER2(void)
  33 {
  34     if (!poll_scrollwheel)
  35         call_tick_tasks();  /* Run through the list of tick tasks */
  36     else
  37     {
  38         if (!button_hold())
  39             button_read_dbop();
  40     }
  41
  42     poll_scrollwheel ^= 1;
  43     TIMER2_INTCLR = 0;  /* clear interrupt */
  44 }
  45 #else
  46 void INT_TIMER2(void)
  47 {
  48     call_tick_tasks();  /* Run through the list of tick tasks */
  49
  50     TIMER2_INTCLR = 0;  /* clear interrupt */
  51 }
  52 #endif
  53
  54 void tick_start(unsigned int interval_in_ms)
  55 {
  56     int phi = 0;                            /* prescaler bits */
  57     int prescale = 1;
  58     int cycles = TIMER_FREQ / 1000 * interval_in_ms;
  59
  60     while(cycles > 0x10000)
  61     {
  62         phi++;
  63         prescale <<= 4;
  64         cycles >>= 4;
  65     }
  66
  67     if(prescale > 256)
  68         panicf("%s : interval too big", __func__);
  69
  70     CGU_PERI |= CGU_TIMER2_CLOCK_ENABLE;    /* enable peripheral */
  71     VIC_INT_ENABLE |= INTERRUPT_TIMER2;     /* enable interrupt */
  72
  73     TIMER2_LOAD = TIMER2_BGLOAD = cycles;   /* timer period */
  74
  75     /* /!\ bit 4 (reserved) must not be modified
  76      * periodic mode, interrupt enabled, 16 bits counter */
  77     TIMER2_CONTROL = (TIMER2_CONTROL & (1<<4)) | 0xe0 | (phi<<2);
  78 }