/* ----------------------------------------------------------------------------
 *         ATMEL Microcontroller Software Support
 * ----------------------------------------------------------------------------
 * Copyright (c) 2009, 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:
 *
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 * this list of conditions and the disclaimer below.
 *
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/** \addtogroup spi_pdc_module SPI PDC driver
 * The Spi driver is a low level spi driver which performs SPI device Initializes,
 * spi transfer and receive. It can be used by upper SPI driver such as AT45
 * driver and AT26 driver.
 *
 * \usage
 * <ul>
 * <li> Initializes a SPI instance and the corresponding SPI hardware,
 *    Configure SPI in Master Mode using SPID_Configure().</li>
 * <li> Configures the SPI characteristics (such as Clock Polarity, Phase,
 *    transfers delay and Baud Rate) for the device corresponding to the
 *    chip select using SPID_ConfigureCS().</li>
 * <li> Starts a SPI master transfer using SPID_SendCommand().
 *    The transfer is performed using the PDC channels. </li>
 *    <li> It enable the SPI clock.</li>
 *    <li> Set the corresponding peripheral chip select.</li>
 *    <li> Initialize the two SPI PDC buffers.</li>
 *       <li> Initialize SPI_TPR and SPI_TCR with SPI command data and size
 *         to send command data first.</li>
 *       <li> Initialize SPI_RPR and SPI_RCR with SPI command data and size
 *         as dummy value.</li>
 *       <li> Initialize SPI_TNPR and SPI_TNCR with rest of the data to be
 *        transfered.(if the data specified in cmd structure)</li>
 *       <li> Initialize SPI_RNPR and SPI_RNCR with rest of the data to be
 *         received.(if the data specified in cmd structure)</li>
 *    <li> Initialize the callback function if specified.</li>
 *    <li> Enable transmitter and receiver.</li>
 *    <li> Example for sending a command to the dataflash through the SPI.</li>
 * \code
 *      /// Build command to be sent.
 *      ...
 *      // Send Command and data through the SPI
 *      if (SPID_SendCommand(pAt45->pSpid, pCommand)) {
 *          return AT45_ERROR_SPI;
 *      }
 * \endcode
 * <li> The SPI_Handler() must be called by the SPI Interrupt Service Routine
 *    with the corresponding Spi instance. It is invokes to check for pending
 *    interrupts. </li>
 *    <li> Example for initializing SPI interrupt handler in upper application.</li>
 * \code
 *        AIC_ConfigureIT(AT91C_ID_SPI, 0, SPI_Handler);
 * \endcode
 * </ul>
 * Related files :\n
 * \ref spi_pdc.c\n
 * \ref spi_pdc.h.\n
*/
/*@{*/
/*@}*/


/**
 * \file
 *
 * Implementation of SPI PDC driver.
 *
 */

/*----------------------------------------------------------------------------
 *        Headers
 *----------------------------------------------------------------------------*/

#include "spi_pdc.h"
#include <board.h>

/*----------------------------------------------------------------------------
 *        Macros
 *----------------------------------------------------------------------------*/

/** Write PMC register*/
#define WRITE_PMC(pPmc, regName, value) pPmc->regName = (value)

/** Write SPI register*/
#define WRITE_SPI(pSpi, regName, value) pSpi->regName = (value)

/** Read SPI registers */
#define READ_SPI(pSpi, regName) (pSpi->regName)

/*----------------------------------------------------------------------------
 *        Exported functions
 *----------------------------------------------------------------------------*/

/**
 * \brief Initializes the Spid structure and the corresponding SPI hardware.
 *
 * \param pSpid  Pointer to a Spid instance.
 * \param pSpiHw Associated SPI peripheral.
 * \param spiId SPI peripheral identifier.
 * \return 0.
 */
uint8_t SPID_Configure(Spid *pSpid, Spi *pSpiHw, uint8_t spiId)
{
    /* Initialize the SPI structure*/
    pSpid->pSpiHw = pSpiHw;
    pSpid->spiId  = spiId;
    pSpid->semaphore = 1;
    pSpid->pCurrentCommand = 0;

    /* Enable the SPI clock*/
    WRITE_PMC(PMC, PMC_PCER0, (1 << pSpid->spiId));

    /* Execute a software reset of the SPI twice */
    WRITE_SPI(pSpiHw, SPI_CR, SPI_CR_SWRST);
    WRITE_SPI(pSpiHw, SPI_CR, SPI_CR_SWRST);

    /* Configure SPI in Master Mode with No CS selected !!! */
    WRITE_SPI(pSpiHw, SPI_MR, SPI_MR_MSTR | SPI_MR_MODFDIS | SPI_MR_PCS);

    /* Enable the SPI*/
    WRITE_SPI(pSpiHw, SPI_CR, SPI_CR_SPIEN);

    /* Enable the SPI clock*/
    WRITE_PMC(PMC, PMC_PCDR0, (1 << pSpid->spiId));

    return 0;
}

/**
 * \brief Configures the parameters for the device corresponding to the cs.
 *
 * \param pSpid  Pointer to a Spid instance.
 * \param cs  number corresponding to the SPI chip select.
 * \param csr  SPI_CSR value to setup.
 */
void SPID_ConfigureCS(Spid *pSpid, uint8_t cs, uint32_t csr)
{
    Spi *pSpiHw = pSpid->pSpiHw;
    WRITE_SPI(pSpiHw, SPI_CSR[cs], csr);
}

/**
 * \brief Starts a SPI master transfer. This is a non blocking function. It will
 * return as soon as the transfer is started.
 *
 * \param pSpid  Pointer to a Spid instance.
 * \param pCommand Pointer to the SPI command to execute.
 * \return 0 if the transfer has been started successfully; otherwise returns
 * SPID_ERROR_LOCK is the driver is in use, or SPID_ERROR if the command is not
 * valid.
 */
uint8_t SPID_SendCommand(Spid *pSpid, SpidCmd *pCommand)
{
    Spi *pSpiHw = pSpid->pSpiHw;
    uint32_t spiMr;

    /* Try to get the dataflash semaphore */
    if (pSpid->semaphore == 0) {

        return SPID_ERROR_LOCK;
    }
    pSpid->semaphore--;

    /* Enable the SPI clock */
    WRITE_PMC(PMC, PMC_PCER0, (1 << pSpid->spiId));

    /* Disable transmitter and receiver*/
    WRITE_SPI(pSpiHw, SPI_PTCR, SPI_PTCR_RXTDIS | SPI_PTCR_TXTDIS);

    /* Write to the MR register*/
    spiMr = READ_SPI(pSpiHw, SPI_MR);
    spiMr |= SPI_MR_PCS;
    spiMr &= ~((1 << pCommand->spiCs) << 16);
    WRITE_SPI(pSpiHw, SPI_MR, spiMr);

    /* Initialize the two SPI PDC buffer*/
    WRITE_SPI(pSpiHw, SPI_RPR, (int) pCommand->pCmd);
    WRITE_SPI(pSpiHw, SPI_RCR, pCommand->cmdSize);
    WRITE_SPI(pSpiHw, SPI_TPR, (int) pCommand->pCmd);
    WRITE_SPI(pSpiHw, SPI_TCR, pCommand->cmdSize);

    WRITE_SPI(pSpiHw, SPI_RNPR, (int) pCommand->pData);
    WRITE_SPI(pSpiHw, SPI_RNCR, pCommand->dataSize);
    WRITE_SPI(pSpiHw, SPI_TNPR, (int) pCommand->pData);
    WRITE_SPI(pSpiHw, SPI_TNCR, pCommand->dataSize);

    /* Initialize the callback*/
    pSpid->pCurrentCommand = pCommand;

    /* Enable transmitter and receiver*/
    WRITE_SPI(pSpiHw, SPI_PTCR, SPI_PTCR_RXTEN | SPI_PTCR_TXTEN);

    /* Enable buffer complete interrupt*/
    WRITE_SPI(pSpiHw, SPI_IER, SPI_IER_RXBUFF);

    return 0;
}


/**
 * \brief The SPI_Handler must be called by the SPI Interrupt Service Routine with the
 * corresponding Spi instance.
 *
 * \note The SPI_Handler will unlock the Spi semaphore and invoke the upper application
 * callback.
 * \param pSpid  Pointer to a Spid instance.
 */
void SPID_Handler(Spid *pSpid)
{
    SpidCmd *pSpidCmd = pSpid->pCurrentCommand;
    Spi *pSpiHw = pSpid->pSpiHw;
    volatile uint32_t spiSr;

    /* Read the status register*/
    spiSr = READ_SPI(pSpiHw, SPI_SR);
    if (spiSr & SPI_SR_RXBUFF) {

        /* Disable transmitter and receiver */
        WRITE_SPI(pSpiHw, SPI_PTCR, SPI_PTCR_RXTDIS | SPI_PTCR_TXTDIS);

        /* Disable the SPI clock*/
        WRITE_PMC(PMC, PMC_PCDR0, (1 << pSpid->spiId));

        /* Disable buffer complete interrupt */
        WRITE_SPI(pSpiHw, SPI_IDR, SPI_IDR_RXBUFF);

        /* Release the dataflash semaphore*/
        pSpid->semaphore++;

        /* Invoke the callback associated with the current command*/
        if (pSpidCmd && pSpidCmd->callback) {

            pSpidCmd->callback(0, pSpidCmd->pArgument);
        }

        /* Nothing must be done after. A new DF operation may have been started
         in the callback function.*/
    }
}

/**
 * \brief Returns 1 if the SPI driver is currently busy executing a command; otherwise
 * returns 0.
 * \param pSpid  Pointer to a Spid instance.
 */
uint8_t SPID_IsBusy(const Spid *pSpid)
{
    if (pSpid->semaphore == 0) {

        return 1;
    }
    else {

        return 0;
    }
}