rockbox/firmware/target/arm/as3525/kernel-as3525.c
2009-06-03 11:35:56 +00:00

78 lines
2.3 KiB
C

/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright © 2008 Rafaël Carré
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#include "config.h"
#include "system.h"
#include "kernel.h"
#include "panic.h"
#include "timer-target.h"
#ifdef HAVE_SCROLLWHEEL
#include "button-target.h"
/* The scrollwheel is polled every 5 ms (the tick tasks only every 10) */
static volatile int poll_scrollwheel = 0;
void INT_TIMER2(void)
{
if (!poll_scrollwheel)
call_tick_tasks(); /* Run through the list of tick tasks */
else
{
if (!button_hold())
button_read_dbop();
}
poll_scrollwheel ^= 1;
TIMER2_INTCLR = 0; /* clear interrupt */
}
#else
void INT_TIMER2(void)
{
call_tick_tasks(); /* Run through the list of tick tasks */
TIMER2_INTCLR = 0; /* clear interrupt */
}
#endif
void tick_start(unsigned int interval_in_ms)
{
int phi = 0; /* prescaler bits */
int prescale = 1;
int cycles = TIMER_FREQ / 1000 * interval_in_ms;
while(cycles > 0x10000)
{
phi++;
prescale <<= 4;
cycles >>= 4;
}
if(prescale > 256)
panicf("%s : interval too big", __func__);
CGU_PERI |= CGU_TIMER2_CLOCK_ENABLE; /* enable peripheral */
VIC_INT_ENABLE |= INTERRUPT_TIMER2; /* enable interrupt */
TIMER2_LOAD = TIMER2_BGLOAD = cycles; /* timer period */
/* /!\ bit 4 (reserved) must not be modified
* periodic mode, interrupt enabled, 16 bits counter */
TIMER2_CONTROL = (TIMER2_CONTROL & (1<<4)) | 0xe0 | (phi<<2);
}