/*---------------------------------------------------------------------------*
  Project:  CtrBrom - libraries - OS
  File:     os_tick.c

  Copyright 2008 Nintendo.  All rights reserved.

  These coded instructions, statements, and computer programs contain
  proprietary information of Nintendo of America Inc. and/or Nintendo
  Company Ltd., and are protected by Federal copyright law.  They may
  not be disclosed to third parties or copied or duplicated in any form,
  in whole or in part, without the prior written consent of Nintendo.

  $Date::            $
  $Rev$
  $Author$
 *---------------------------------------------------------------------------*/
#include <brom/os.h>


//----------------------------------------------------------------------
//---- timer number tick uses
#define OSi_TICK_TIMER         OS_TIMER_0

#ifdef SDK_ARM11
//---- timer interrupt ID
#define OSi_TICK_IE_TIMER_ID    OS_INTR_ID_TIMER

#else // SDK_ARM9
//---- timer interrupt ID
#define OSi_TICK_IE_TIMER_ID    OS_INTR_ID_TIMER0

//---- timer interrupt mask (must be same number with OSi_TICK_TIMER)
#define OSi_TICK_IE_TIMER      REG_OS_IF_T0_MASK

//---- timer control setting for tick
#define OSi_TICK_TIMERCONTROL  ( REG_OS_TM0CNT_H_E_MASK | REG_OS_TM0CNT_H_I_MASK | OS_TIMER_PRESCALER_64 )
#endif // SDK_ARM9

//---- flag for initialization tick
static u16 i_osUseTick = FALSE;

//---- tick counter
vu64    i_osTickCounter;

//---- flag for need to re-set timer
BOOL    i_osNeedResetTimer = FALSE;

extern u16  i_osIsTimerReserved(int timerNum);
extern void i_osSetTimerReserved(int timerNum);

static void i_osCountUpTick(void);

/*---------------------------------------------------------------------------*
  Name:         osInitTick

  Description:  initialize 'tick system'

  Arguments:    None

  Returns:      None
 *---------------------------------------------------------------------------*/
void osInitTick(void)
{
    if (!i_osUseTick)
    {
        i_osUseTick = TRUE;

        //---- disable timer interrupt
        osDisableInterruptID(OSi_TICK_IE_TIMER_ID);

        osInitInterrupt();
        osInitTimer();

        i_osTickCounter = 0;

        //---- OS reserves OSi_TICK_TIMER timer
        SDK_ASSERT(!i_osIsTimerReserved(OSi_TICK_TIMER));
        i_osSetTimerReserved(OSi_TICK_TIMER);

#ifdef SDK_ARM11
        osStopTimer(OSi_TICK_TIMER);
        osEnableTimerReload(OSi_TICK_TIMER);
        osStartTimer(OSi_TICK_TIMER, OS_TICK_LO_LIMIT, 0);
#else // SDK_ARM9
        //---- setting timer
        osSetTimerControl(OSi_TICK_TIMER, 0);
        osSetTimerCount((OSTimer)OSi_TICK_TIMER, (u16)0);
        osSetTimerControl(OSi_TICK_TIMER, (u16)OSi_TICK_TIMERCONTROL);
#endif // SDK_ARM9

        //---- set interrupt callback
        osSetInterruptHandler( OSi_TICK_IE_TIMER_ID, i_osCountUpTick );

        //---- enable timer interrupt
        osEnableInterruptID(OSi_TICK_IE_TIMER_ID);

        //---- need to reset
        i_osNeedResetTimer = TRUE;
    }
}

/*---------------------------------------------------------------------------*
  Name:         osIsTickAvailable

  Description:  check tick system is available

  Arguments:    None

  Returns:      if available, TRUE.
 *---------------------------------------------------------------------------*/
BOOL osIsTickAvailable(void)
{
    return i_osUseTick;
}


/*---------------------------------------------------------------------------*
  Name:         i_osCountUpTick

  Description:  timer interrupt handle. 

  Arguments:    None

  Returns:      None
 *---------------------------------------------------------------------------*/
static void i_osCountUpTick(void)
{
    i_osTickCounter++;

    //---- setting for timer
    if (i_osNeedResetTimer)
    {
#ifdef SDK_ARM11
        osStopTimer(OSi_TICK_TIMER);
        osStartTimer(OSi_TICK_TIMER, OS_TICK_LO_LIMIT, 0);
#else // SDK_ARM9
        osSetTimerControl(OSi_TICK_TIMER, 0);
        osSetTimerCount((OSTimer)OSi_TICK_TIMER, (u16)0);
        osSetTimerControl(OSi_TICK_TIMER, (u16)OSi_TICK_TIMERCONTROL);
#endif // SDK_ARM9

        i_osNeedResetTimer = FALSE;
    }

// これはやらなくても、毎回コールバックがかかるから問題ない？
//    //---- reset callback
//    OSi_EnterTimerCallback(OSi_TICK_TIMER, (void (*)(void *))i_osCountUpTick, 0);
}

/*---------------------------------------------------------------------------*
  Name:         osGetTick

  Description:  get tick value

  Arguments:    None

  Returns:      tick value
 *---------------------------------------------------------------------------*/
u64 osGetTick(void)
{
    vu32    countL;
    vu64    countH;

    OSIntrMode prev = osDisableInterrupts();
    SDK_ASSERT(i_osUseTick);

    countL = osGetTimerCount(OSi_TICK_TIMER);
#ifdef SDK_ARM11
    countL = OS_TICK_LO_LIMIT - countL;
#endif // SDK_ARM11
    countH = i_osTickCounter;

    //---- check if timer interrupt bit is on
    if (osIsInterruptPending(OSi_TICK_IE_TIMER_ID) &&
        // countLが0xFFFFで直後に割り込み要求が来た場合の対策
#ifdef SDK_ARM11
        // ダウンカウンタなので
        (countL & OS_TICK_LO_MSB)
#else // SDK_ARM9
        // アップカウンタなので
        !(countL & OS_TICK_LO_MSB)
#endif // SDK_ARM9
       )
    {
        countH++;
    }
    
    countH <<= OS_TICK_HI_SHIFT;

    (void)osRestoreInterrupts(prev);

    return countH | countL;
}

/*---------------------------------------------------------------------------*
  Name:         osGetTickLo

  Description:  get tick value (only u16 part)

  Arguments:    None

  Returns:      tick value (only u16 part)
 *---------------------------------------------------------------------------*/
OSTimerCount osGetTickLo(void)
{
    SDK_ASSERT(OSi_UseTick);
    return osGetTimerCount(OSi_TICK_TIMER);
}

/*---------------------------------------------------------------------------*
  Name:         i_osSetTick

  Description:  set tick value

  Arguments:    count     value of tick to be set

  Returns:      None
 *---------------------------------------------------------------------------*/
void i_osSetTick(u64 count)
{
    OSIntrMode prev;

    SDK_ASSERT(i_osUseTick);
    prev = osDisableInterrupts();

    i_osNeedResetTimer = TRUE;

    i_osTickCounter = (u64)(count >> OS_TICK_HI_SHIFT);

#ifdef SDK_ARM11
    osStopTimer(OSi_TICK_TIMER);
    osClearInterruptPendingID(OSi_TICK_IE_TIMER_ID);

    osStartTimer(OSi_TICK_TIMER, (u32)(count & OS_TICK_LO_MASK), 0);

#else // SDK_ARM9
    osSetTimerControl(OSi_TICK_TIMER, 0);
    osClearInterruptPendingID(OSi_TICK_IE_TIMER_ID);

    osSetTimerCount((OSTimer)OSi_TICK_TIMER, (u16)(count & OS_TICK_LO_MASK));
    osSetTimerControl(OSi_TICK_TIMER, (u16)OSi_TICK_TIMERCONTROL);

#endif // SDK_ARM9

    (void)osRestoreInterrupts(prev);
}