idle.c

来自「该BSP是基于PXA270+WINCE的BSP」· C语言 代码 · 共 77 行

//
// Copyright (c) Microsoft Corporation.  All rights reserved.
//
//
// Use of this source code is subject to the terms of the Microsoft end-user
// license agreement (EULA) under which you licensed this SOFTWARE PRODUCT.
// If you did not accept the terms of the EULA, you are not authorized to use
// this source code. For a copy of the EULA, please see the LICENSE.RTF on your
// install media.
//
//------------------------------------------------------------------------------
//
//  File:  idle.c
//

#include <windows.h>
#include <nkintr.h>
#include <pkfuncs.h>
#include <bulverde_base_regs.h>
#include <bulverde_memctrl.h>
#include <oal.h>

//------------------------------------------------------------------------------
// Defines 
 
//------------------------------------------------------------------------------
// External Variables 

//------------------------------------------------------------------------------
// Global Variables 
 
//------------------------------------------------------------------------------
// Local Variables 
static PBULVERSE_MEMCTRL_REG m_pMemCtrl = 0; 

//------------------------------------------------------------------------------
// Local Functions 
//
//  Function:     OALCPUIdle
//
//  This function is called by the common implementation of variable OEMIdle.
//  OEMIdle 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 off when OALCPUIdle is called. Interrrupts are also turned off when OALCPUIdle returns.
//

void OALCPUIdle()
{
    extern void CPUEnterIdle(void);

    if (!m_pMemCtrl)
        m_pMemCtrl = (PBULVERSE_MEMCTRL_REG) OALPAtoUA(BULVERDE_BASE_REG_PA_MEMC);

    // Enable Auto power down of SDRAM & synchronous flash
    //
    m_pMemCtrl->mdrefr |= MEMCTRL_MDREFR_APD;
        
    INTERRUPTS_ON();
    
    CPUEnterIdle();

    INTERRUPTS_OFF();

    // Disable auto power down of SDRAM & synchronous flash
    // (If APD is set a latency penalty of one memory cycle is incurred for 
    //  restarting SDCLK and SDCKE between non-consecutive SDRAM/synchronous
    //  memory flash transfers. Disabling APD improves the memory throughput
    //  during normal operation)
    //
    m_pMemCtrl->mdrefr &= ~(MEMCTRL_MDREFR_APD);

}
//------------------------------------------------------------------------------