rockbox/firmware/target/mips/ingenic_jz47xx/timer-jz4740.c

/***************************************************************************
 *             __________               __   ___.
 *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
 *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
 *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
 *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
 *                     \/            \/     \/    \/            \/
 * $Id$
 *
 * Copyright (C) 2008 by Maurus Cuelenaere
 *
 * 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 "jz4740.h"
#include "system.h"
#include "timer.h"

/* Interrupt handler */
void TCU1(void)
{
    __tcu_clear_full_match_flag(1);
    
    if (pfn_timer != NULL)
        pfn_timer();
}

/* TODO: figure out what cycles means */
bool __timer_set(long cycles, bool start)
{
    unsigned int latch, old_irq;
    
    if(cycles < 1)
        return false;
    
    if (start && pfn_unregister != NULL)
    {
        pfn_unregister();
        pfn_unregister = NULL;
    }
    
    old_irq = disable_irq_save();
    
    __tcu_stop_counter(1);
    __tcu_disable_pwm_output(1);
    
    __tcu_mask_half_match_irq(1); 
    __tcu_unmask_full_match_irq(1);

    /* EXTAL clock = 12Mhz */
    __tcu_select_extalclk(1);
    /* 12Mhz / 4 = 3Mhz */
    __tcu_select_clk_div4(1);
    
    latch = cycles;

    REG_TCU_TCNT(1) = 0;
    REG_TCU_TDFR(1) = latch;
    REG_TCU_TDHR(1) = latch;

    __tcu_clear_full_match_flag(1);
    
    system_enable_irq(IRQ_TCU1);
    
    restore_irq(old_irq);
    
    return true;
}

bool __timer_register(void)
{
    unsigned int old_irq = disable_irq_save();
    
    __tcu_start_counter(1);
    
    restore_irq(old_irq);
    
    return true;
}

void __timer_unregister(void)
{
    unsigned int old_irq = disable_irq_save();
    
    __tcu_stop_counter(1);
    
    restore_irq(old_irq);
}