#include <xs1.h>
#include <platform.h>
#include <xclib.h>
#include <print.h>

#include "xperipherals_spi.h"

#ifdef XPERIPHERALS_SPI_1

#if XPERIPHERALS_SPI_1__BUS_MASTER
	
    on tile[XPERIPHERALS_SPI_1__TILE_NUMBER] : out port _xperipherals_spi_1__pin_sclk = XPERIPHERALS_SPI_1__SCLK_PORT;
    on tile[XPERIPHERALS_SPI_1__TILE_NUMBER] : out port _xperipherals_spi_1__pin_mosi = XPERIPHERALS_SPI_1__MOSI_PORT;
    on tile[XPERIPHERALS_SPI_1__TILE_NUMBER] : in  port _xperipherals_spi_1__pin_miso = XPERIPHERALS_SPI_1__MISO_PORT;

#else
	
    on tile[XPERIPHERALS_SPI_1__TILE_NUMBER] : in port  _xperipherals_spi_1__pin_sclk = XPERIPHERALS_SPI_1__SCLK_PORT;
    on tile[XPERIPHERALS_SPI_1__TILE_NUMBER] : out port _xperipherals_spi_1__pin_mosi = XPERIPHERALS_SPI_1__MOSI_PORT;
    on tile[XPERIPHERALS_SPI_1__TILE_NUMBER] : in  port _xperipherals_spi_1__pin_miso = XPERIPHERALS_SPI_1__MISO_PORT;

#endif

#if XPERIPHERALS_SPI_1__BUS_MASTER
static timer _xperipherals_spi_1__io_timer;
static int   _xperipherals_spi_1__io_time;
#else
static xbyte _xperipherals_spi_1__sclk;
#endif
static int   _xperipherals_spi_1__io_state;

static int   _xperipherals_spi_1__shift_cnt;
static xbyte _xperipherals_spi_1__mosi_data;
static xbyte _xperipherals_spi_1__miso_data;
static xbyte _xperipherals_spi_1__temp_data;

// <TODO> Calulate based on current system clock frequency

#define _XPERIPHERALS_SPI_1__TIME_BASE ((400000 / XPERIPHERALS_SPI_1__BIT_RATE) * 62)

#if XPERIPHERALS_SPI_1__BUS_MASTER

void xperipherals_spi_1__initialize( void )
{
    _xperipherals_spi_1__io_state = 0;
    _xperipherals_spi_1__pin_sclk <: (XPERIPHERALS_SPI_1__MODE_CPOL != 0);
    _xperipherals_spi_1__io_timer :> _xperipherals_spi_1__io_time;
    _xperipherals_spi_1__io_timer when timerafter( _xperipherals_spi_1__io_time + 10 * _XPERIPHERALS_SPI_1__TIME_BASE ) :> void;
}

void xperipherals_spi_1__begin_write( xbyte mosi_data ) { xperipherals_spi_1__begin_xfer( mosi_data ); }
void xperipherals_spi_1__begin_read ( void )            { xperipherals_spi_1__begin_xfer( 0x00 ); }

void xperipherals_spi_1__begin_xfer( xbyte mosi_data )
{
    _xperipherals_spi_1__mosi_data = mosi_data;
    _xperipherals_spi_1__pin_sclk <: !((XPERIPHERALS_SPI_1__MODE_CPOL !=0) ^ (XPERIPHERALS_SPI_1__MODE_CPHA !=0 ));
    _xperipherals_spi_1__pin_mosi <: (xbyte)(_xperipherals_spi_1__mosi_data & 1);
    _xperipherals_spi_1__miso_data = 0;
    _xperipherals_spi_1__shift_cnt = 1;
    _xperipherals_spi_1__io_timer :> _xperipherals_spi_1__io_time;
    _xperipherals_spi_1__io_state = 1;
}

//                                   +-------+       +-------+       +-------+
// CPOL = 0, CPHA = 0                |       |       |       |       |       |
//                      -------------+       +-------+       +-------+       +
//                           +---------------+---------------+---------------+
// CPOL = 0, CPHA = 0   XXXXX|       0       |       1       |       2       |
//                           +---------------+---------------+---------------+
//                           Beg     S1      S2      S1      S2      S1      S2
//
//                      -------------+       +-------+       +-------+       +
// CPOL = 1, CPHA = 0                |       |       |       |       |       |
//                                   +-------+       +-------+       +-------+
//                           +---------------+---------------+---------------+
// CPOL = 1, CPHA = 0   XXXXX|       0       |       1       |       2       |
//                           +---------------+---------------+---------------+
//                           Beg     S1      S2      S1      S2      S1      S2
//
//                           +-------+       +-------+       +-------+
// CPOL = 0, CPHA = 1        |       |       |       |       |       |
//                      -----+       +-------+       +-------+       +-------+
//                           +---------------+---------------+---------------+
// CPOL = 0, CPHA = 1   XXXXX|       0       |       1       |       2       |
//                           +---------------+---------------+---------------+
//                           Beg     S1      S2      S1      S2      S1      S2
//
//                      -----+       +-------+       +-------+       +-------+
// CPOL = 1, CPHA = 1        |       |       |       |       |       |
//                           +-------+       +-------+       +-------+
//                           +---------------+---------------+---------------+
// CPOL = 1, CPHA = 1   XXXXX|       0       |       1       |       2       |
//                           +---------------+---------------+---------------+
//                           Beg     S1      S2      S1      S2      S1      S2

select xperipherals_spi_1__continue_io( int& status )
{
    case _xperipherals_spi_1__io_state > 0 => _xperipherals_spi_1__io_timer when timerafter(_xperipherals_spi_1__io_time) :> _xperipherals_spi_1__io_time:

        switch( _xperipherals_spi_1__io_state )
        {
            case 1: // S1

            _xperipherals_spi_1__pin_miso :> _xperipherals_spi_1__temp_data;
            _xperipherals_spi_1__pin_sclk <: ((XPERIPHERALS_SPI_1__MODE_CPOL !=0) ^ (XPERIPHERALS_SPI_1__MODE_CPHA !=0 ));
            _xperipherals_spi_1__miso_data |=  (_xperipherals_spi_1__temp_data << _xperipherals_spi_1__shift_cnt) & 1;

            _xperipherals_spi_1__io_state = 2;
            status = XPERIPHERALS_SPI__STATUS__NONE;
            break;

            case 2: // S2

            if( _xperipherals_spi_1__shift_cnt <= 7 )
            {
                _xperipherals_spi_1__pin_sclk <: !((XPERIPHERALS_SPI_1__MODE_CPOL !=0) ^ (XPERIPHERALS_SPI_1__MODE_CPHA !=0 ));
                _xperipherals_spi_1__pin_mosi <: (xbyte)(_xperipherals_spi_1__mosi_data >> _xperipherals_spi_1__shift_cnt++) & 1;
                _xperipherals_spi_1__io_state = 1;
                status = XPERIPHERALS_SPI__STATUS__NONE;
            }
            else
            {
                _xperipherals_spi_1__pin_sclk <: !((XPERIPHERALS_SPI_1__MODE_CPOL !=0 ) ^ (XPERIPHERALS_SPI_1__MODE_CPHA !=0 ));
                _xperipherals_spi_1__io_state = 0;
                status = XPERIPHERALS_SPI__STATUS__EVENT_IO_DONE;
            }
            break;
        }
        break;
}

xbyte xperipherals_spi_1__get_data( void ) { return _xperipherals_spi_1__miso_data; }

int xperipherals_spi_1__write( xbyte mosi_data )  { xbyte tmp; return xperipherals_spi_1__transfer( mosi_data, tmp ); }
int xperipherals_spi_1__read ( xbyte& miso_data ) { return xperipherals_spi_1__transfer( 0x00, miso_data ); }

int xperipherals_spi_1__transfer( xbyte mosi_data, xbyte& miso_data )
{
    int status;
    xperipherals_spi_1__begin_write( mosi_data );
    while( TRUE ) {
        select {case xperipherals_spi_1__io_continue( status );}
        if( status != XPERIPHERALS_SPI__STATUS__NONE ) break;
    }
    return status;
}

#else

#if XPERIPHERALS_SPI_1__BUS_MASTER

void xperipherals_spi_1__initialize( void )
{
}

int xperipherals_spi_1__write( xbyte mosi_data )
{
    return 0;
}

int xperipherals_spi_1__read( xbyte& miso_data )
{
    return 0;
}

xbyte xperipherals_spi_1__transfer( xbyte mosi_data )
{
    return 0;
}

void xperipherals_spi_1__xfer_start( xbyte mosi_data )
{
    return 0;
}

select xperipherals_spi_1__xfer_done( xbool& done_flag, xbyte& miso_data )
{
    return 0;
}

void xperipherals_spi_1__begin_write( xbyte mosi_data )
{
    return 0;
}

void xperipherals_spi_1__begin_read( void )
{
    return 0;
}

void xperipherals_spi_1__begin_xfer( xbyte mosi_data )
{
    #endif
}

select xperipherals_spi_1__continue_io( int& status )
{
}

xbyte xperipherals_spi_1__get_data( void )
{
    return _xperipherals_spi_1__data;
}

#endif

#endif