/*
 * Copyright (C) 2001-2005 by egnite Software GmbH. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the copyright holders nor the names of
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
 * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * For additional information see http://www.ethernut.de/
 *
 */

/*
 * $Log$
 * Revision 1.7  2008/08/22 09:25:33  haraldkipp
 * Clock value caching and new functions NutArchClockGet, NutClockGet and
 * NutClockSet added.
 *
 * Revision 1.6  2008/08/11 06:59:12  haraldkipp
 * BSD types replaced by stdint types (feature request #1282721).
 *
 * Revision 1.5  2008/07/08 08:25:04  haraldkipp
 * NutDelay is no more architecture specific.
 * Number of loops per millisecond is configurable or will be automatically
 * determined.
 * A new function NutMicroDelay provides shorter delays.
 *
 * Revision 1.4  2006/10/08 16:48:07  haraldkipp
 * Documentation fixed
 *
 * Revision 1.3  2005/10/24 17:59:19  haraldkipp
 * Use correct header file, arm, not gba.
 *
 * Revision 1.2  2005/08/02 17:46:45  haraldkipp
 * Major API documentation update.
 *
 * Revision 1.1  2005/07/26 18:02:26  haraldkipp
 * Moved from dev.
 *
 * Revision 1.2  2005/07/20 09:17:26  haraldkipp
 * Default NUT_CPU_FREQ and NUT_TICK_FREQ added.
 * NutTimerIntr() removed, because we can use the hardware independent code.
 *
 * Revision 1.1  2005/05/27 17:16:40  drsung
 * Moved the file.
 *
 * Revision 1.5  2005/04/05 17:50:46  haraldkipp
 * Use register names in gba.h.
 *
 * Revision 1.4  2004/11/08 19:16:37  haraldkipp
 * Hacked in Gameboy timer support
 *
 * Revision 1.3  2004/10/03 18:42:21  haraldkipp
 * No GBA support yet, but let the compiler run through
 *
 * Revision 1.2  2004/09/08 10:19:39  haraldkipp
 * Running on AT91 and S3C, thanks to James Tyou
 *
 */

#include <cfg/arch.h>
#include <arch/arm.h>
#include <dev/irqreg.h>

/*!
 * \addtogroup xgNutArchArmOsTimerGba
 */
/*@{*/

#ifndef NUT_CPU_FREQ
#define NUT_CPU_FREQ    1000000UL
#endif

#ifndef NUT_TICK_FREQ
#define NUT_TICK_FREQ   1000UL
#endif

static void (*os_handler) (void *);

/*!
 * \brief Timer 0 interrupt entry.
 */
void Timer3Entry(void *arg)
{
    outw(REG_IF, INT_TMR3);
    os_handler(0);
}

/*!
 * \brief Initialize system timer.
 *
 * This function is automatically called by Nut/OS
 * during system initialization.
 *
 * Nut/OS uses on-chip timer 0 for its timer services.
 * Applications should not modify any registers of this
 * timer, but make use of the Nut/OS timer API. Timer 1
 * and timer 2 are available to applications.
 */
void NutRegisterTimer(void (*handler) (void *))
{
    os_handler = handler;


    /* Disable master interrupt. */
    outw(REG_IME, 0);

    /* Set global interrupt vector. */
    NutRegisterIrqHandler(&sig_TMR3, Timer3Entry, 0);

    /* Enable timer and timer interrupts. */
    outdw(REG_TMR3CNT, TMR_IRQ_ENA | TMR_ENA | 48756);

    /* Enable timer 3 interrupts. */
    outw(REG_IE, inw(REG_IE) | INT_TMR3);

    /* Enable master interrupt. */
    outw(REG_IME, 1);
}

/*!
 * \brief Return the CPU clock in Hertz.
 *
 * \return CPU clock frequency in Hertz, which is 16780000 for the GBA.
 */
uint32_t NutArchClockGet(int idx)
{
    return NUT_CPU_FREQ;
}

/*!
 * \brief Return the number of system ticks per second.
 *
 * \return System tick frequency in Hertz.
 */
uint32_t NutGetTickClock(void)
{
    return NUT_TICK_FREQ;
}

/*!
 * \brief Calculate system ticks for a given number of milliseconds.
 */
uint32_t NutTimerMillisToTicks(uint32_t ms)
{
#if (NUT_TICK_FREQ % 1000)
    if (ms >= 0x3E8000UL)
        return (ms / 1000UL) * NUT_TICK_FREQ;
    return (ms * NUT_TICK_FREQ + 999UL) / 1000UL;
#else
    return ms * (NUT_TICK_FREQ / 1000UL);
#endif
}

/*@}*/