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Arduino/hardware/sam/system/libsam/source/spi_pdc.c

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C

/* ----------------------------------------------------------------------------
* 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:
*
* - 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.
* ----------------------------------------------------------------------------
*/
/** \addtogroup spi_pdc_module SPI PDC driver
* \ingroup spi_at45_module
* 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.
*
* \section 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 "chip.h"
/*----------------------------------------------------------------------------
* 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.
*/
extern uint32_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*/
PMC_EnablePeripheral( pSpid->spiId ) ;
/* Configure SPI in Master Mode with No CS selected !!! */
SPI_Configure( pSpiHw, pSpid->spiId, SPI_MR_MSTR | SPI_MR_MODFDIS | SPI_MR_PCS_Msk ) ;
/* Enable the SPI */
SPI_Enable( pSpiHw ) ;
/* Disable the SPI clock */
PMC_DisablePeripheral( 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.
*/
extern void SPID_ConfigureCS( Spid* pSpid, uint32_t dwCS, uint32_t dwCSR )
{
SPI_ConfigureNPCS( pSpid->pSpiHw, dwCS, dwCSR ) ;
}
/**
* \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.
*/
extern uint32_t SPID_SendCommand( Spid* pSpid, SpidCmd* pCommand )
{
Spi* pSpiHw = pSpid->pSpiHw ;
uint32_t dwSpiMr ;
/* Try to get the dataflash semaphore */
if ( pSpid->semaphore == 0 )
{
return SPID_ERROR_LOCK ;
}
pSpid->semaphore-- ;
/* Enable the SPI clock */
PMC_EnablePeripheral( pSpid->spiId ) ;
/* Disable transmitter and receiver*/
SPI_PdcDisableRx( pSpiHw ) ;
SPI_PdcDisableTx( pSpiHw ) ;
/* Write to the MR register*/
dwSpiMr = pSpiHw->SPI_MR ;
dwSpiMr |= SPI_MR_PCS_Msk ;
dwSpiMr &= ~((1 << pCommand->spiCs) << 16 ) ;
pSpiHw->SPI_MR=dwSpiMr ;
/* Initialize the two SPI PDC buffer*/
SPI_PdcSetRx( pSpiHw, pCommand->pCmd, pCommand->cmdSize, pCommand->pData, pCommand->dataSize ) ;
SPI_PdcSetTx( pSpiHw, pCommand->pCmd, pCommand->cmdSize, pCommand->pData, pCommand->dataSize ) ;
/* Initialize the callback*/
pSpid->pCurrentCommand = pCommand ;
/* Enable transmitter and receiver*/
SPI_PdcEnableRx( pSpiHw ) ;
SPI_PdcEnableTx( pSpiHw ) ;
/* Enable buffer complete interrupt*/
SPI_EnableIt( pSpiHw, 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.
*/
extern void SPID_Handler( Spid* pSpid )
{
SpidCmd *pSpidCmd = pSpid->pCurrentCommand ;
Spi *pSpiHw = pSpid->pSpiHw ;
volatile uint32_t spiSr ;
/* Read the status register*/
spiSr = pSpiHw->SPI_SR ;
if ( spiSr & SPI_SR_RXBUFF )
{
/* Disable transmitter and receiver */
SPI_PdcDisableRx( pSpiHw ) ;
SPI_PdcDisableTx( pSpiHw ) ;
/* Disable the SPI clock*/
PMC_DisablePeripheral( pSpid->spiId ) ;
/* Disable buffer complete interrupt */
SPI_DisableIt( pSpiHw, 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.
*/
extern uint32_t SPID_IsBusy( const Spid* pSpid )
{
if ( pSpid->semaphore == 0 )
{
return 1 ;
}
else
{
return 0 ;
}
}