/*---------------------------------------------------------------------------*
  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 control setting for tick
#define OSi_TICK_TIMERCONTROL  ( REG_OS_TM0CNT_H_E_MASK | REG_OS_TM0CNT_H_I_MASK | OS_TIMER_PRESCALER_64 )

//---- timer number tick uses
#define OSi_TICK_TIMER         OS_TIMER_3

//---- timer interrupt mask (must be same number with OSi_TICK_TIMER)
#define OSi_TICK_IE_TIMER      REG_OS_IF_T3_MASK

//---- timer interrupt ID
#define OSi_TICK_IE_TIMER_ID    OS_INTR_ID_TIMER3

//---- 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;

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

        //---- setting timer
        i_osTickCounter = 0;
        i_osSetTimerControl(OSi_TICK_TIMER, 0);
        i_osSetTimerCount((OSTimer)OSi_TICK_TIMER, (u16)0);
        i_osSetTimerControl(OSi_TICK_TIMER, (u16)OSi_TICK_TIMERCONTROL);

        //---- set interrupt callback
        osSetInterruptHandler( OS_INTR_ID_TIMER3, i_osCountUpTick );

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

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

/*---------------------------------------------------------------------------*
  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)
    {
        i_osSetTimerControl(OSi_TICK_TIMER, 0);
        i_osSetTimerCount((OSTimer)OSi_TICK_TIMER, (u16)0);
        i_osSetTimerControl(OSi_TICK_TIMER, (u16)OSi_TICK_TIMERCONTROL);

        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)
{
    vu16    countL;
    vu64    countH;

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

    countL = *(REGType16 *)((u32)REG_TM0CNT_L_ADDR + OSi_TICK_TIMER * 4);
    countH = i_osTickCounter & 0xffffffffffffULL;

    //---- check if timer interrupt bit is on
    if (reg_OS_IF & OSi_TICK_IE_TIMER && !(countL & 0x8000))
    {
        countH++;
    }
    
    (void)osRestoreInterrupts(prev);

    return (countH << 16) | countL;
}

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

  Description:  get tick value (only u16 part)

  Arguments:    None

  Returns:      tick value (only u16 part)
 *---------------------------------------------------------------------------*/
u16 osGetTickLo(void)
{
    SDK_ASSERT(OSi_UseTick);
    return *(REGType16 *)((u32)REG_TM0CNT_L_ADDR + OSi_TICK_TIMER * 4);
}

/*---------------------------------------------------------------------------*
  Name:         osSetTick

  Description:  set tick value

  Arguments:    count     value of tick to be set

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

    SDK_ASSERT(i_osUseTick);
    prev = osDisableInterrupts();

    reg_OS_IF = OSi_TICK_IE_TIMER;

    i_osNeedResetTimer = TRUE;

    i_osTickCounter = (u64)(count >> 16);

    i_osSetTimerControl(OSi_TICK_TIMER, 0);
    i_osSetTimerCount((OSTimer)OSi_TICK_TIMER, (u16)(count & 0xffff));
    i_osSetTimerControl(OSi_TICK_TIMER, (u16)OSi_TICK_TIMERCONTROL);

    (void)osRestoreInterrupts(prev);
}