timer.c

三星2440原版bsp

//  Function: OALTimerIntrHandler
//
//  This function implement timer interrupt handler. It is called from common
//  ARM interrupt handler.
//
UINT32 OALTimerIntrHandler()
{
    volatile S3C2440X_INTR_REG *pIntr = (S3C2440X_INTR_REG*)OALPAtoVA(S3C2440X_BASE_REG_PA_INTR, FALSE);
    UINT32 sysIntr = SYSINTR_NOP;

    // Update high resolution counter
    g_oalTimer.curCounts += g_oalTimer.countsPerSysTick*g_idleMSec;
                             
    // Update the millisecond counter
    CurMSec += g_idleMSec;
//	RETAILMSG(1,(TEXT("(%x)"), g_idleMSec));

	OALTimerUpdate(g_oalTimer.countsPerSysTick, g_oalTimer.countsMargin);
	g_idleMSec = g_oalTimer.msecPerSysTick;

    // Reschedule?
    if ((int)(CurMSec - dwReschedTime) >= 0) sysIntr = SYSINTR_RESCHED;

#ifdef OAL_ILTIMING
    if (g_oalILT.active) {
        if (--g_oalILT.counter == 0) {
            sysIntr = SYSINTR_TIMING;
            g_oalILT.counter = g_oalILT.counterSet;
            g_oalILT.isrTime2 = OALTimerCountsSinceSysTick();
        }
    }
#endif

#ifdef DVS_EN
#if (DVS_METHOD == 3)
	ChangeSystemStateDVS();
#endif
#endif
    return sysIntr;
}


//------------------------------------------------------------------------------
//
//  Function: OALTimerCountsSinceSysTick
//
//  This function return count of hi res ticks since system tick.
//
//  Timer 4 counts down, so we should substract actual value from 
//  system tick period.
//

INT32 OALTimerCountsSinceSysTick()
{
//    return (g_oalTimer.countsPerSysTick - INREG32(&g_pPWMRegs->TCNTB4));
// Must be TCNTO4, TCNTB4 represents the written data, not counted data.
    return (INREG32(&g_pPWMRegs->TCNTB4) - INREG32(&g_pPWMRegs->TCNTO4));
}

//------------------------------------------------------------------------------
//
//  Function: OALTimerUpdate
//
//  This function is called to change length of actual system timer period.
//  If end of actual period is closer than margin period isn't changed (so
//  original period elapse). Function returns time which already expires
//  in new period length units. If end of new period is closer to actual time
//  than margin period end is shifted by margin (but next period should fix
//  this shift - this is reason why OALTimerRecharge doesn't read back 
//  compare register and it uses saved value instead).
//
UINT32 OALTimerUpdate(UINT32 period, UINT32 margin)
{
	UINT32 tcon, ret;
	
	ret = OALTimerCountsSinceSysTick()/g_oalTimer.countsPerSysTick;

	OUTREG32(&g_pPWMRegs->TCNTB4, period);
    tcon = INREG32(&g_pPWMRegs->TCON) & ~(0x0F << 20);
    OUTREG32(&g_pPWMRegs->TCON, tcon | (0x2 << 20) );
    OUTREG32(&g_pPWMRegs->TCON, tcon | (0x1 << 20) );

	return (ret);
/*
    UINT32 rc, count, offset, edge;

    count = OALTimerGetCount();
    edge = count + margin;

    if (period == 0) {
        // Period is zero, let interrupt occurs asap
        rc = 0;
        g_timer.compare = edge;
        OALTimerSetCount(g_timer.compare);
    } else if ((INT32)(g_timer.compare - edge) > 0) {
        // We are more than margin before actual compare, update period
        offset = count - g_timer.base;
        // Avoid divide/multiply for most cases
        if ((INT32)(offset - period) <= 0) {
            rc = 0;
        } else {            
            rc = offset/period;
            g_timer.base += rc * period;         
        }
        // New compare value is base plus period
        g_timer.compare = g_timer.base + period;
        // Are we more than margin before new compare?
        if ((INT32)(g_timer.compare - edge) > 0) {
            // Yes, then use calculated value
            OALTimerSetCompare(g_timer.compare);
        } else {
            // No, shift real compare value
            OALTimerSetCompare(edge);
        }            
    } else {
        // No, stay with original period
        rc = (g_timer.compare - g_timer.base)/period - 1;
    }    
    return rc;
*/
}

//------------------------------------------------------------------------------
//
//  Function:     OEMIdle
//
//  This function is called by the kernel when there are no threads ready to 
//  run. The CPU should be put into a reduced power mode if possible and halted. 
//  It is important to be able to resume execution quickly upon receiving an 
//  interrupt.
//
//  Interrupts are disabled when OEMIdle is called and when it returns.
//
//  Note that system timer must be running when CPU/SoC is moved to reduced
//  power mode.
//
void OEMIdle(DWORD idleParam)
{
    UINT32 baseMSec, idleMSec, idleSysTicks;
    INT32 usedCounts, idleCounts;
    ULARGE_INTEGER idle;

    // Get current system timer counter
    baseMSec = CurMSec;

    // Compute the remaining idle time
    idleMSec = dwReschedTime - baseMSec;
//	RETAILMSG(1,(TEXT("(%d)"), idleMSec));
    
    // Idle time has expired - we need to return
    if ((INT32)idleMSec <= 0) return;

	// Limit the maximum idle time to what is supported.  
	// Counter size is the limiting parameter.  When kernel 
	// profiler or interrupt latency timing is active it is set
	// to one system tick.
	if (idleMSec > g_oalTimer.maxPeriodMSec) {
		idleMSec = g_oalTimer.maxPeriodMSec;
	}

	// We can wait only full systick
	idleSysTicks = idleMSec/g_oalTimer.msecPerSysTick;

	// This is idle time in hi-res ticks
	idleCounts = idleSysTicks * g_oalTimer.countsPerSysTick;

    // Find how many hi-res ticks was already used
    usedCounts = OALTimerCountsSinceSysTick();

//	RETAILMSG(1,(TEXT("(%x, %x)"), idleCounts, usedCounts));
	if (idleCounts == usedCounts)
	{
		RETAILMSG(1,(TEXT("(%x, %x)"), idleCounts, usedCounts));
		return;
	}

    // Prolong beat period to idle time -- don't do it idle time isn't
    // longer than one system tick. Even if OALTimerExtendSysTick function
    // should accept this value it can cause problems if kernel profiler
    // or interrupt latency timing is active.
    if (idleSysTicks > 1) {
        // Extend timer period
        OALTimerUpdate(idleCounts-usedCounts, g_oalTimer.countsMargin);
        // Update value for timer interrupt which wakeup from idle
        g_oalTimer.actualMSecPerSysTick = idleMSec;
        g_oalTimer.actualCountsPerSysTick = idleCounts;
    }

	g_idleMSec = idleMSec;

    // Move SoC/CPU to idle mode
    OALCPUIdle();
	INTERRUPTS_OFF();

    // Return system tick period back to original. Don't call when idle
    // time was one system tick. See comment above.
    if (idleSysTicks > 1) {
        // If there wasn't timer interrupt we have to update CurMSec&curCounts
        if (CurMSec == baseMSec) {
			// Return system tick period back to original
			idleSysTicks = OALTimerUpdate(g_oalTimer.countsPerSysTick, g_oalTimer.countsMargin);

			g_idleMSec = g_oalTimer.msecPerSysTick;
//			RETAILMSG(1,(TEXT("(%x)"), idleSysTicks));

            // Restore original values
			g_oalTimer.actualMSecPerSysTick = g_oalTimer.msecPerSysTick;
			g_oalTimer.actualCountsPerSysTick = g_oalTimer.countsPerSysTick;

            // Fix system tick counters & idle counter
			CurMSec += idleSysTicks * g_oalTimer.actualMSecPerSysTick;
			idleCounts = idleSysTicks * g_oalTimer.actualCountsPerSysTick;
			g_oalTimer.curCounts += idleCounts;
			idleCounts += OALTimerCountsSinceSysTick();
        }
    } else {
        if (CurMSec == baseMSec) {
			// Update actual idle counts, if there wasn't timer interrupt
			idleCounts = OALTimerCountsSinceSysTick();
//			RETAILMSG(1,(TEXT("(%x)"), idleCounts));
        }
    }

    // Get real idle value. If result is negative we didn't idle at all.
    idleCounts -= usedCounts;

    if (idleCounts < 0) idleCounts = 0;

//	RETAILMSG(1,(TEXT("(%x, %x)"), idleCounts, (CurMSec - baseMSec)*g_oalTimer.countsPerSysTick));

    // Update idle counters
    idle.LowPart = curridlelow;
    idle.HighPart = curridlehigh;
    idle.QuadPart += idleCounts;
    curridlelow  = idle.LowPart;
    curridlehigh = idle.HighPart;

#ifdef DVS_EN
	dwCurrentidle = (idle.QuadPart/idleconv);
#endif
}

//------------------------------------------------------------------------------