aon_rtc.c

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/******************************************************************************
*  Filename:       aon_rtc.c
*  Revised:        2015-06-24 13:36:23 +0200 (Wed, 24 Jun 2015)
*  Revision:       44023
*
*  Description:    Driver for the AON RTC.
*
*  Copyright (c) 2015, Texas Instruments Incorporated
*  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 ORGANIZATION nor the names of its 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 HOLDER 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
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*  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.
*
******************************************************************************/

#include <driverlib/aon_rtc.h>
#include <driverlib/cpu.h>

//*****************************************************************************
//
// Handle support for DriverLib in ROM:
// This section will undo prototype renaming made in the header file
//
//*****************************************************************************
#if !defined(DOXYGEN)
    #undef  AONRTCCurrentCompareValueGet
    #define AONRTCCurrentCompareValueGet    NOROM_AONRTCCurrentCompareValueGet
    #undef  AONRTCCurrent64BitValueGet
    #define AONRTCCurrent64BitValueGet      NOROM_AONRTCCurrent64BitValueGet
#endif


//*****************************************************************************
//
// Get the current value of the RTC counter in a format compatible to the compare registers.
//
//*****************************************************************************
uint32_t
AONRTCCurrentCompareValueGet( void )
{
    uint32_t   ui32CurrentSec    ;
    uint32_t   ui32CurrentSubSec ;
    uint32_t   ui32SecondSecRead ;

    //
    // Reading SEC both before and after SUBSEC in order to detect if SEC incremented while reading SUBSEC
    // If SEC incremented, we can’t be sure which SEC the SUBSEC belongs to, so repeating the sequence then.
    //
    do {
        ui32CurrentSec    = HWREG( AON_RTC_BASE + AON_RTC_O_SEC    );
        ui32CurrentSubSec = HWREG( AON_RTC_BASE + AON_RTC_O_SUBSEC );
        ui32SecondSecRead = HWREG( AON_RTC_BASE + AON_RTC_O_SEC    );
    } while ( ui32CurrentSec != ui32SecondSecRead );

    return (( ui32CurrentSec << 16 ) | ( ui32CurrentSubSec >> 16 ));
}

//*****************************************************************************
//
// Get the current 64-bit value of the RTC counter.
//
//*****************************************************************************
uint64_t
AONRTCCurrent64BitValueGet( void )
{
    union {
        uint64_t  returnValue       ;
        uint32_t  secAndSubSec[ 2 ] ;
    } currentRtc                    ;
    uint32_t      ui32SecondSecRead ;

    //
    // Reading SEC both before and after SUBSEC in order to detect if SEC incremented while reading SUBSEC
    // If SEC incremented, we can’t be sure which SEC the SUBSEC belongs to, so repeating the sequence then.
    //
    do {
        currentRtc.secAndSubSec[ 1 ] = HWREG( AON_RTC_BASE + AON_RTC_O_SEC    );
        currentRtc.secAndSubSec[ 0 ] = HWREG( AON_RTC_BASE + AON_RTC_O_SUBSEC );
        ui32SecondSecRead            = HWREG( AON_RTC_BASE + AON_RTC_O_SEC    );
    } while ( currentRtc.secAndSubSec[ 1 ] != ui32SecondSecRead );

    return ( currentRtc.returnValue );
}