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/* ----------------------------------------------------------------------------

 *         ATMEL Microcontroller Software Support

 * ----------------------------------------------------------------------------

 * Copyright (c) 2008, Atmel Corporation

 *

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions are met:

 *

 * - Redistributions of source code must retain the above copyright notice,

 * this list of conditions and the disclaimer below.

 *

 * Atmel's name may not be used to endorse or promote products derived from

 * this software without specific prior written permission.

 *

 * DISCLAIMER: THIS SOFTWARE IS PROVIDED BY ATMEL "AS IS" AND ANY EXPRESS OR

 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF

 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT ARE

 * DISCLAIMED. IN NO EVENT SHALL ATMEL 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 INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF

 * LIABILITY, WHETHER IN 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.

 * ----------------------------------------------------------------------------

 */

#if defined(at91cap9)

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

//         Headers

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

#include "slck.h"

#include <utility/assert.h>

#include <utility/trace.h>

#include <utility/util.h>

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

//         Local definitions

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

/// Start Up Time Slow Clock 32K Oscillator // see DC characteritics in Datasheet

#define T_ST_SLCK_32K_IN_MS  1200 

/// Start Up Time Slow Clock RC Oscillator  // see DC characteritics in Datasheet

#define T_ST_SLCK_RC_IN_US     75 

#define FREQ_SLCK_32K     32768 // see DC characteritics in Datasheet

#define MIN_FREQ_SLCK_RC  20000 // see DC characteritics in Datasheet

#define TIME_5_CYCLES_32K_IN_US     ((2 * 5 * 1000000) / FREQ_SLCK_32K)

#define TIME_5_CYCLES_RC_IN_US      ((2 * 5 * 1000000) / MIN_FREQ_SLCK_RC)

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

//         Local functions

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

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

/// Wait time in ms

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

// not precise, depends on the compiler and on the options

static void WaitTimeInMs(unsigned int pck, unsigned int time_ms)

{

    register unsigned int i = 0;

    i = (pck / 1000) * time_ms;

    i = i / 4;

    while(i--);

}

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

/// Wait time in us

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

// not precise, depends on the compiler and on the options

static void WaitTimeInUs(unsigned int pck, unsigned int time_us)

{

    volatile unsigned int i = 0;

    i = (pck / 1000000) * time_us;

    i = i / 4;

    while(i--);

}

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

//         Global functions

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

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

/// Return 1 if the slow clock is 32k

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

unsigned char SLCK_Is32k(void)

{

    return ((*AT91C_SYS_SLCKSEL & AT91C_SLCKSEL_OSCSEL) != 0);

}

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

/// Configure the 32kHz oscillator for the slow clock

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

void SLCK_RCto32k(void)

{

    // Check that the master clock has a different source than slow clock. If no,

    if( (AT91C_BASE_PMC->PMC_MCKR & AT91C_PMC_CSS) == 0)

    {

        TRACE_WARNING("The master clock use the slow clock. " \

            "Not possible to change Slow clock\n\r");

        return;

    }

    // Check that the slow clock source is RC

    if( SLCK_Is32k() )

    {

        TRACE_WARNING("The slow clock is already the external 32.768kHz crystal\n\r");

        return;

    }

    // Enable the 32,768 Hz oscillator by setting the bit OSC32EN to 1.

    *AT91C_SYS_SLCKSEL |= AT91C_SLCKSEL_OSC32EN;

    // Wait 32,768 Hz Startup Time for clock stabilization (software loop).    

    WaitTimeInMs(BOARD_MCK*2, T_ST_SLCK_32K_IN_MS);

    // Switch from internal RC to 32,768 Hz oscillator by setting the bit OSCSEL to 1.

    *AT91C_SYS_SLCKSEL |= AT91C_SLCKSEL_OSCSEL;

    // Wait 5 slow clock cycles for internal resynchronization.   

    WaitTimeInUs(BOARD_MCK*2, TIME_5_CYCLES_32K_IN_US);

    // Disable the RC oscillator by setting the bit RCEN to 0.    

    *AT91C_SYS_SLCKSEL &= (0xFFFFFFFF ^ AT91C_SLCKSEL_RCEN);

    TRACE_INFO("The slow clock is now the external 32.768kHz crystal\n\r");

}

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

/// Configure the RC oscillator for the slow clock

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

void SLCK_32ktoRC(void)

{

    // Check that the master clock has a different source than slow clock.

    if( (AT91C_BASE_PMC->PMC_MCKR & AT91C_PMC_CSS) == 0)

    {

        TRACE_WARNING("The master clock use the slow clock. " \

            "Not possible to change Slow clock\n\r");

        return;

    }

    // Check that the slow clock source is RC

    if( !SLCK_Is32k() )

    {

        TRACE_WARNING("The slow clock is already the internal RC oscillator\n\r");

        return;

    }

    // Enable the internal RC oscillator by setting the bit RCEN to 1

    *AT91C_SYS_SLCKSEL |= AT91C_SLCKSEL_RCEN;

    // Wait internal RC Startup Time for clock stabilization (software loop).

    WaitTimeInUs(BOARD_MCK*2, T_ST_SLCK_RC_IN_US);

    // Switch from 32768 Hz oscillator to internal RC by setting the bit OSCSEL to 0.

    *AT91C_SYS_SLCKSEL &= (0xFFFFFFFF ^ AT91C_SLCKSEL_OSCSEL);

    // Wait 5 slow clock cycles for internal resynchronization.

    WaitTimeInUs(BOARD_MCK*2, TIME_5_CYCLES_RC_IN_US);

    // Disable the 32768 Hz oscillator by setting the bit OSC32EN to 0.   

    *AT91C_SYS_SLCKSEL &= (0xFFFFFFFF ^ AT91C_SLCKSEL_OSC32EN);

    TRACE_INFO("The slow clock is now the internal RC oscillator\n\r");

}

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

/// by pass the 32kHz oscillator

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

void SLCK_bypass32Kosc(void)

{

    // Enable the bypass path OSC32BYP bit set to 1

    *AT91C_SYS_SLCKSEL |= AT91C_SLCKSEL_OSC32BYP;

    // Disable the 32,768 Hz oscillator by setting the bit OSC32EN to 0

    *AT91C_SYS_SLCKSEL &= (0xFFFFFFFF ^ AT91C_SLCKSEL_OSC32EN);

}

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

/// set Slow Clock Mode

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

#define TIMEOUT             10000000

void SLCK_UtilSetSlowClockMode(unsigned int timeInSlowClockMode)

{

    unsigned int oldPll;

    unsigned int oldMck;

    unsigned int timeout = 0;

    // Save previous values for PLL A and Master Clock configuration

    oldPll = AT91C_BASE_CKGR->CKGR_PLLAR;

    oldMck = AT91C_BASE_PMC->PMC_MCKR;

    // Slow clock is selected for Master Clock 

    // 32kKz / 64 = 500Hz

    // PCK = 500Hz, MCK = 250 MHz

    AT91C_BASE_PMC->PMC_MCKR = AT91C_PMC_CSS_SLOW_CLK | AT91C_PMC_PRES_CLK_64 | AT91C_PMC_MDIV_2;

    timeout = 0;

    while ( !(AT91C_BASE_PMC->PMC_SR & AT91C_PMC_MCKRDY) && timeout++ < TIMEOUT);

    // Stop PLL A

    // MULA: PLL A Multiplier 0 = The PLL A is deactivated.

    AT91C_BASE_CKGR->CKGR_PLLAR = 0x00003f00;

    // Stop Main Oscillator

    AT91C_BASE_CKGR->CKGR_MOR = AT91C_BASE_CKGR->CKGR_MOR & (~AT91C_CKGR_MOSCEN);

    // Wait a while. The clock is at 500Hz...

    while( timeInSlowClockMode-- );

    // End !  

    // Restart Main Oscillator    

    AT91C_BASE_CKGR->CKGR_MOR = AT91C_BASE_CKGR->CKGR_MOR | (AT91C_CKGR_OSCOUNT & (0x32<<8) );

    AT91C_BASE_CKGR->CKGR_MOR = AT91C_BASE_CKGR->CKGR_MOR | (AT91C_CKGR_MOSCEN);

    // Restart PLL A

    AT91C_BASE_CKGR->CKGR_PLLAR = oldPll;

    timeout = 0;

    while( !(AT91C_BASE_PMC->PMC_SR & AT91C_PMC_LOCKA) && timeout++ < TIMEOUT);

    // Selection of Master Clock MCK (so Processor Clock PCK)

    AT91C_BASE_PMC->PMC_MCKR = oldMck;

    timeout = 0;

    while( !(AT91C_BASE_PMC->PMC_SR & AT91C_PMC_MCKRDY) && timeout++ < TIMEOUT);

    // Reconfigure DBGU

    TRACE_CONFIGURE(DBGU_STANDARD, 115200, BOARD_MCK);

}

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

/// get the slow clock frequency

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

unsigned int SLCK_UtilGetFreq(void)

{

    unsigned int freq = 0;

    SLCK_UtilSetSlowClockMode(0);

    if(AT91C_BASE_PMC->PMC_MCFR & (1<<16)) {

        freq = BOARD_MAINOSC / (AT91C_BASE_PMC->PMC_MCFR & 0x0000FFFF);

        freq *= 16;

    }

    return freq;

}

#endif //#if defined(at91cap9)