/**************************************************************************
*
*  spi. - SPI functions to connect an Arduidno to the TI CC3000
*
*  This code uses the Arduino hardware SPI library (or a bit-banged
*  SPI for the Teensy 3.0) to send & receive data between the library
*  API calls and the CC3000 hardware. Every
*
*  Version 1.0.1b
*
*  Copyright (C) 2013 Chris Magagna - cmagagna@yahoo.com
*
*  Redistribution and use in source and binary forms, with or without
*  modification, are permitted provided that the following conditions
*  are met:
*
*  Don't sue me if my code blows up your board and burns down your house
*
****************************************************************************/

#include <stdio.h>
#include <debug.h>
#include <string.h>
#include <unistd.h>
#include <nuttx/config.h>
#include <nuttx/spi/spi.h>
#include <arch/board/kl_wifi.h>
#include <nuttx/wireless/cc3000/hci.h>
#include <nuttx/wireless/cc3000/spi.h>
//#include <nuttx/wireless/cc3000/ArduinoCC3000Core.h>

// This flag lets the interrupt handler know if it should respond to
// the WL_SPI_IRQ pin going low or not
int16_t SPIInterruptsEnabled=0;


#define READ                    3
#define WRITE                   1

#define HI(value)               (((value) & 0xFF00) >> 8)
#define LO(value)               ((value) & 0x00FF)

#define HEADERS_SIZE_EVNT       (SPI_HEADER_SIZE + 5)

#define SPI_HEADER_SIZE         (5)

#define eSPI_STATE_POWERUP              (0)
#define eSPI_STATE_INITIALIZED          (1)
#define eSPI_STATE_IDLE                 (2)
#define eSPI_STATE_WRITE_IRQ            (3)
#define eSPI_STATE_WRITE_FIRST_PORTION  (4)
#define eSPI_STATE_WRITE_EOT            (5)
#define eSPI_STATE_READ_IRQ             (6)
#define eSPI_STATE_READ_FIRST_PORTION   (7)
#define eSPI_STATE_READ_EOT             (8)

/* !!!HACK!!!*/
#define KL_PORTA_ISFR 0x400490a0
#define PIN16 16
#define getreg32(a)          (*(volatile uint32_t *)(a))
#define putreg32(v,a)        (*(volatile uint32_t *)(a) = (v))

#undef SPI_DEBUG   /* Define to enable debug */
#undef SPI_VERBOSE /* Define to enable verbose debug */

#ifdef SPI_DEBUG
#  define spidbg  lldbg
#  ifdef SPI_VERBOSE
#    define spivdbg lldbg
#  else
#    define spivdbg(x...)
#  endif
#else
#  undef SPI_VERBOSE
#  define spidbg(x...)
#  define spivdbg(x...)
#endif

#ifdef CONFIG_KL_SPI0
void kl_spi0select(FAR struct spi_dev_s *dev, enum spi_dev_e devid,
                   bool selected)
{
  spivdbg("devid: %d CS: %s\n",
           (int)devid, selected ? "assert" : "de-assert");
}
#endif

#ifdef CONFIG_KL_SPI1
void kl_spi1select(FAR struct spi_dev_s *dev, enum spi_dev_e devid,
                   bool selected)
{
  spivdbg("devid: %d CS: %s\n",
           (int)devid, selected ? "assert" : "de-assert");
}
#endif

#ifdef CONFIG_KL_SPI0
uint8_t kl_spi0status(FAR struct spi_dev_s *dev, enum spi_dev_e devid)
{
  return 0;
}
#endif

#ifdef CONFIG_KL_SPI1
uint8_t kl_spi1status(FAR struct spi_dev_s *dev, enum spi_dev_e devid)
{
  return 0;
}
#endif

typedef struct
{
  gcSpiHandleRx  SPIRxHandler;

  uint16_t usTxPacketLength;
  uint16_t usRxPacketLength;
  unsigned long  ulSpiState;
  uint8_t *pTxPacket;
  uint8_t *pRxPacket;

} tSpiInformation;

tSpiInformation sSpiInformation;

//
// Static buffer for 5 bytes of SPI HEADER
//
uint8_t tSpiReadHeader[] = {READ, 0, 0, 0, 0};

// The magic number that resides at the end of the TX/RX buffer (1 byte after the allocated size)
// for the purpose of detection of the overrun. The location of the memory where the magic number
// resides shall never be written. In case it is written - the overrun occured and either recevie function
// or send function will stuck forever.
#define CC3000_BUFFER_MAGIC_NUMBER (0xDE)

char spi_buffer[CC3000_RX_BUFFER_SIZE];
uint8_t wlan_tx_buffer[CC3000_TX_BUFFER_SIZE];

struct spi_dev_s *spi = NULL;

unsigned int SPIPump(uint8_t data)
{
  uint8_t rx;

  printf("SPIPump tx = 0x%X ", data);

  if (!spi)
    {
      spi = up_spiinitialize(1);
      SPI_SETBITS(spi, 8);
      SPI_SETMODE(spi, SPIDEV_MODE1);
    }

  SPI_EXCHANGE(spi, &data, &rx, 1);

  printf(" rx = 0x%X\n", rx);

  return rx;
}

//*****************************************************************************
//
//! This function enter point for write flow
//!
//!  \param  SpiPauseSpi
//!
//!  \return none
//!
//!  \brief  The function triggers a user provided callback for
//
//*****************************************************************************

void SpiPauseSpi(void)
{
  SPIInterruptsEnabled = 0;
}

//*****************************************************************************
//
//! This function enter point for write flow
//!
//!  \param  SpiResumeSpi
//!
//!  \return none
//!
//!  \brief  The function triggers a user provided callback for
//
//*****************************************************************************

void SpiResumeSpi(void)
{
  SPIInterruptsEnabled = 1;
}

//*****************************************************************************
//
//! This function enter point for write flow
//!
//!  \param  SpiTriggerRxProcessing
//!
//!  \return none
//!
//!  \brief  The function triggers a user provided callback for
//
//*****************************************************************************
void SpiTriggerRxProcessing(void)
{
  //
  // Trigger Rx processing
  //
  SpiPauseSpi();
  DeassertWlanCS();

  // The magic number that resides at the end of the TX/RX buffer (1 byte after the allocated size)
  // for the purpose of detection of the overrun. If the magic number is overriten - buffer overrun
  // occurred - and we will stuck here forever!

  if (sSpiInformation.pRxPacket[CC3000_RX_BUFFER_SIZE - 1] != CC3000_BUFFER_MAGIC_NUMBER)
    {
      while (1)
        ;
    }

  sSpiInformation.ulSpiState = eSPI_STATE_IDLE;
  sSpiInformation.SPIRxHandler(sSpiInformation.pRxPacket + SPI_HEADER_SIZE);
}

//*****************************************************************************
//
//! This function enter point for write flow
//!
//!  \param  buffer
//!
//!  \return none
//!
//!  \brief  ...
//
//*****************************************************************************

void SpiReadDataSynchronous(uint8_t *data, uint16_t size)
{
  long i = 0;
    uint8_t *data_to_send = tSpiReadHeader;

  for (i = 0; i < size; i ++)
    {
      data[i] = SPIPump(data_to_send[0]);
    }
}

//*****************************************************************************
//
//! This function enter point for write flow
//!
//!  \param  buffer
//!
//!  \return none
//!
//!  \brief  ...
//
//*****************************************************************************

void SpiWriteDataSynchronous(uint8_t *data, uint16_t size)
{
  while (size)
    {
      SPIPump(*data);
      size --;
      data++;
    }
}

//*****************************************************************************
//
//! This function enter point for write flow
//!
//!  \param  buffer
//!
//!  \return none
//!
//!  \brief  ...
//
//*****************************************************************************
long SpiFirstWrite(uint8_t *ucBuf, uint16_t usLength)
{
  //
  // workaround for first transaction
  //

  AssertWlanCS();

  usleep(70);

  // SPI writes first 4 bytes of data

  SpiWriteDataSynchronous(ucBuf, 4);

  usleep(70);

  SpiWriteDataSynchronous(ucBuf + 4, usLength - 4);

  sSpiInformation.ulSpiState = eSPI_STATE_IDLE;

  DeassertWlanCS();

  //printf("Executed SpiFirstWrite!\n");

  return(0);
}

//*****************************************************************************
//
//! This function enter point for write flow
//!
//!  \param  buffer
//!
//!  \return none
//!
//!  \brief  ...
//
//*****************************************************************************

long SpiWrite(uint8_t *pUserBuffer, uint16_t usLength)
{
  uint8_t ucPad = 0;

  //
  // Figure out the total length of the packet in order to figure out if there is padding or not
  //

  if(!(usLength & 0x0001))
    {
      ucPad++;
    }

  pUserBuffer[0] = WRITE;
  pUserBuffer[1] = HI(usLength + ucPad);
  pUserBuffer[2] = LO(usLength + ucPad);
  pUserBuffer[3] = 0;
  pUserBuffer[4] = 0;

  usLength += (SPI_HEADER_SIZE + ucPad);

  // The magic number that resides at the end of the TX/RX buffer (1 byte after the allocated size)
  // for the purpose of overrun detection. If the magic number is overwritten - buffer overrun
  // occurred - and we will be stuck here forever!

  if (wlan_tx_buffer[CC3000_TX_BUFFER_SIZE - 1] != CC3000_BUFFER_MAGIC_NUMBER)
    {
      while (1)
        ;
    }

  if (sSpiInformation.ulSpiState == eSPI_STATE_POWERUP)
    {
      while (sSpiInformation.ulSpiState != eSPI_STATE_INITIALIZED)
        {
        }
    }

  if (sSpiInformation.ulSpiState == eSPI_STATE_INITIALIZED)
    {
      //
      // This is time for first TX/RX transactions over SPI:
      // the IRQ is down - so need to send read buffer size command
      //

      SpiFirstWrite(pUserBuffer, usLength);
    }
  else
    {
      //
      // We need to prevent here race that can occur in case two back to back packets are sent to the
      // device, so the state will move to IDLE and once again to not IDLE due to IRQ
      //

      tSLInformation.WlanInterruptDisable();

      while (sSpiInformation.ulSpiState != eSPI_STATE_IDLE)
       {
         ;
       }

      sSpiInformation.ulSpiState = eSPI_STATE_WRITE_IRQ;
      sSpiInformation.pTxPacket = pUserBuffer;
      sSpiInformation.usTxPacketLength = usLength;

      //
      // Assert the CS line and wait till SSI IRQ line is active and then initialize write operation
      //

      AssertWlanCS();

      //
      // Re-enable IRQ - if it was not disabled - this is not a problem...
      //

      tSLInformation.WlanInterruptEnable();

      //
      // check for a missing interrupt between the CS assertion and enabling back the interrupts
      //

      if (tSLInformation.ReadWlanInterruptPin() == 0)
        {
          SpiWriteDataSynchronous(sSpiInformation.pTxPacket, sSpiInformation.usTxPacketLength);

          sSpiInformation.ulSpiState = eSPI_STATE_IDLE;

          DeassertWlanCS();
        }
    }


  //
  // Due to the fact that we are currently implementing a blocking situation
  // here we will wait till end of transaction
  //

  while (eSPI_STATE_IDLE != sSpiInformation.ulSpiState)
    ;

  return(0);
}

//*****************************************************************************
//
//! This function processes received SPI Header and in accordance with it - continues reading
//!  the packet
//!
//!  \param  None
//!
//!  \return None
//!
//!  \brief  ...
//
//*****************************************************************************

long SpiReadDataCont(void)
{
  long data_to_recv;
  uint8_t *evnt_buff, type;

  //
  //determine what type of packet we have
  //

  evnt_buff =  sSpiInformation.pRxPacket;
  data_to_recv = 0;
  STREAM_TO_UINT8((char *)(evnt_buff + SPI_HEADER_SIZE), HCI_PACKET_TYPE_OFFSET, type);

  switch(type)
    {
      case HCI_TYPE_DATA:
        {
          //
          // We need to read the rest of data..
          //

          STREAM_TO_UINT16((char *)(evnt_buff + SPI_HEADER_SIZE), HCI_DATA_LENGTH_OFFSET, data_to_recv);

          if (!((HEADERS_SIZE_EVNT + data_to_recv) & 1))
            {
              data_to_recv++;
            }

          if (data_to_recv)
            {
              SpiReadDataSynchronous(evnt_buff + 10, data_to_recv);
            }
          break;
        }

      case HCI_TYPE_EVNT:
        {
          //
          // Calculate the rest length of the data
          //

          STREAM_TO_UINT8((char *)(evnt_buff + SPI_HEADER_SIZE), HCI_EVENT_LENGTH_OFFSET, data_to_recv);

          data_to_recv -= 1;

          //
          // Add padding byte if needed
          //

          if ((HEADERS_SIZE_EVNT + data_to_recv) & 1)
            {
              data_to_recv++;
            }

          if (data_to_recv)
           {
              SpiReadDataSynchronous(evnt_buff + 10, data_to_recv);
           }

          sSpiInformation.ulSpiState = eSPI_STATE_READ_EOT;
          break;
        }
    }

    return (0);
}

//*****************************************************************************
//
//! This function enter point for write flow
//!
//!  \param  SSIContReadOperation
//!
//!  \return none
//!
//!  \brief  The function triggers a user provided callback for
//
//*****************************************************************************

void SSIContReadOperation(void)
{
  //
  // The header was read - continue with  the payload read
  //
  if (!SpiReadDataCont())
    {
      //
      // All the data was read - finalize handling by switching to teh task
      //  and calling from task Event Handler
      //

      SpiTriggerRxProcessing();
    }
}

//*****************************************************************************
//
//! This function enter point for read flow: first we read minimal 5 SPI header bytes and 5 Event
//!  Data bytes
//!
//!  \param  buffer
//!
//!  \return none
//!
//!  \brief  ...
//
//*****************************************************************************
void SpiReadHeader(void)
{
  SpiReadDataSynchronous(sSpiInformation.pRxPacket, 10);
}

//*****************************************************************************
//
//!  The IntSpiGPIOHandler interrupt handler
//!
//!  \param  none
//!
//!  \return none
//!
//!  \brief  GPIO A interrupt handler. When the external SSI WLAN device is
//!          ready to interact with Host CPU it generates an interrupt signal.
//!          After that Host CPU has registrated this interrupt request
//!          it set the corresponding /CS in active state.
//
//*****************************************************************************
//#pragma vector=PORT2_VECTOR
//__interrupt void IntSpiGPIOHandler(void)
int CC3000InterruptHandler(int irq, void *context)
{
  uint32_t regval = 0;

  regval = getreg32(KL_PORTA_ISFR);
  if (regval & (1 << PIN16))
    {
      //printf("\nAn interrupt was issued!\n");

      if (!SPIInterruptsEnabled)
        {
          goto out;
        }

      //printf("\nSPIInterrupt was enabled!\n");

      if (sSpiInformation.ulSpiState == eSPI_STATE_POWERUP)
        {
          /* This means IRQ line was low call a callback of HCI Layer to inform on event */

          sSpiInformation.ulSpiState = eSPI_STATE_INITIALIZED;
        }
      else if (sSpiInformation.ulSpiState == eSPI_STATE_IDLE)
        {
          sSpiInformation.ulSpiState = eSPI_STATE_READ_IRQ;

         /* IRQ line goes down - start reception */

         AssertWlanCS();

         //
         // Wait for TX/RX Complete which will come as DMA interrupt
         //

         SpiReadHeader();

         sSpiInformation.ulSpiState = eSPI_STATE_READ_EOT;

         SSIContReadOperation();
        }
      else if (sSpiInformation.ulSpiState == eSPI_STATE_WRITE_IRQ)
        {
          SpiWriteDataSynchronous(sSpiInformation.pTxPacket, sSpiInformation.usTxPacketLength);

          sSpiInformation.ulSpiState = eSPI_STATE_IDLE;

          DeassertWlanCS();
        }
      else
        {
        }

out:
      regval = (1 << PIN16);
      putreg32(regval, KL_PORTA_ISFR);
    }

  return 0;
}

//*****************************************************************************
//
//!  SpiClose
//!
//!  \param  none
//!
//!  \return none
//!
//!  \brief  Cofigure the SSI
//
//*****************************************************************************

void SpiOpen(gcSpiHandleRx pfRxHandler)
{
  sSpiInformation.ulSpiState = eSPI_STATE_POWERUP;

  memset(spi_buffer, 0, sizeof(spi_buffer));
  memset(wlan_tx_buffer, 0, sizeof(spi_buffer));

  sSpiInformation.SPIRxHandler = pfRxHandler;
  sSpiInformation.usTxPacketLength = 0;
  sSpiInformation.pTxPacket = NULL;
  sSpiInformation.pRxPacket = (uint8_t *)spi_buffer;
  sSpiInformation.usRxPacketLength = 0;
  spi_buffer[CC3000_RX_BUFFER_SIZE - 1] = CC3000_BUFFER_MAGIC_NUMBER;
  wlan_tx_buffer[CC3000_TX_BUFFER_SIZE - 1] = CC3000_BUFFER_MAGIC_NUMBER;

  //
  // Enable interrupt on the GPIO pin of WLAN IRQ
  //
  tSLInformation.WlanInterruptEnable();
}

//*****************************************************************************
//
//!  SpiClose
//!
//!  \param  none
//!
//!  \return none
//!
//!  \brief  Cofigure the SSI
//
//*****************************************************************************

void SpiClose(void)
{
  if (sSpiInformation.pRxPacket)
    {
      sSpiInformation.pRxPacket = 0;
    }

  //
  //  Disable Interrupt in GPIOA module...
  //

  tSLInformation.WlanInterruptDisable();
}