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ChibiOS/os/hal/platforms/AT91SAM7/spi_lld.c

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/*
ChibiOS/RT - Copyright (C) 2006,2007,2008,2009,2010,
2011 Giovanni Di Sirio.
This file is part of ChibiOS/RT.
ChibiOS/RT is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
ChibiOS/RT is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/**
* @file AT91SAM7/spi_lld.c
* @brief AT91SAM7 low level SPI driver code.
*
* @addtogroup SPI
* @{
*/
#include "ch.h"
#include "hal.h"
#if HAL_USE_SPI || defined(__DOXYGEN__)
/*===========================================================================*/
/* Driver exported variables. */
/*===========================================================================*/
#if AT91SAM7_SPI_USE_SPI0 || defined(__DOXYGEN__)
/** @brief SPI1 driver identifier.*/
SPIDriver SPID1;
#endif
#if AT91SAM7_SPI_USE_SPI1 || defined(__DOXYGEN__)
/** @brief SPI2 driver identifier.*/
SPIDriver SPID2;
#endif
/*===========================================================================*/
/* Driver local variables. */
/*===========================================================================*/
/**
* @brief Idle line value.
* @details This thing's DMA apparently does not allow to *not* increment
* the memory pointer so a buffer filled with ones is required
* somewhere.
* @note This buffer size also limits the maximum transfer size, 512B,
* for @p spiReceive() and @p spiIgnore(). @p spiSend() and
* @p spiExchange are not affected.
*/
static const uint16_t idle_buf[] = {
0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF
};
/*===========================================================================*/
/* Driver local functions. */
/*===========================================================================*/
/**
* @brief Initializes a SPI device.
*/
static void spi_init(AT91PS_SPI spi) {
/* Software reset must be written twice (errata for revision B parts).*/
spi->SPI_CR = AT91C_SPI_SWRST;
spi->SPI_CR = AT91C_SPI_SWRST;
spi->SPI_RCR = 0;
spi->SPI_RNCR = 0;
spi->SPI_TCR = 0;
spi->SPI_TNCR = 0;
spi->SPI_PTCR = AT91C_PDC_RXTDIS | AT91C_PDC_TXTDIS;
spi->SPI_MR = AT91C_SPI_MSTR | AT91C_SPI_MODFDIS;
}
#if defined(__GNUC__)
__attribute__((noinline))
#endif
/**
* @brief Shared interrupt handling code.
*
* @param[in] spip pointer to the @p SPIDriver object
*/
static void spi_lld_serve_interrupt(SPIDriver *spip) {
uint32_t sr = spip->spi->SPI_SR;
if ((sr & AT91C_SPI_ENDRX) != 0) {
(void)spip->spi->SPI_RDR; /* Clears eventual overflow.*/
spip->spi->SPI_PTCR = AT91C_PDC_RXTDIS |
AT91C_PDC_TXTDIS; /* PDC disabled. */
spip->spi->SPI_IDR = AT91C_SPI_ENDRX; /* Interrupt disabled. */
spip->spi->SPI_CR = AT91C_SPI_SPIDIS; /* SPI disabled. */
/* Portable SPI ISR code defined in the high level driver, note, it is
a macro.*/
_spi_isr_code(spip);
}
}
/*===========================================================================*/
/* Driver interrupt handlers. */
/*===========================================================================*/
#if AT91SAM7_SPI_USE_SPI0 || defined(__DOXYGEN__)
/**
* @brief SPI0 interrupt handler.
*
* @isr
*/
CH_IRQ_HANDLER(SPI0IrqHandler) {
CH_IRQ_PROLOGUE();
spi_lld_serve_interrupt(&SPID1);
AT91C_BASE_AIC->AIC_EOICR = 0;
CH_IRQ_EPILOGUE();
}
#endif
#if AT91SAM7_SPI_USE_SPI1 || defined(__DOXYGEN__)
/**
* @brief SPI1 interrupt handler.
*
* @isr
*/
CH_IRQ_HANDLER(SPI1IrqHandler) {
CH_IRQ_PROLOGUE();
spi_lld_serve_interrupt(&SPID2);
AT91C_BASE_AIC->AIC_EOICR = 0;
CH_IRQ_EPILOGUE();
}
#endif
/*===========================================================================*/
/* Driver exported functions. */
/*===========================================================================*/
/**
* @brief Low level SPI driver initialization.
*
* @notapi
*/
void spi_lld_init(void) {
#if AT91SAM7_SPI_USE_SPI0
spiObjectInit(&SPID1);
SPID1.spi = AT91C_BASE_SPI0;
spi_init(AT91C_BASE_SPI0);
AT91C_BASE_PIOA->PIO_PDR = SPI0_MISO | SPI0_MOSI | SPI0_SCK;
AT91C_BASE_PIOA->PIO_ASR = SPI0_MISO | SPI0_MOSI | SPI0_SCK;
AT91C_BASE_PIOA->PIO_PPUDR = SPI0_MISO | SPI0_MOSI | SPI0_SCK;
AIC_ConfigureIT(AT91C_ID_SPI0,
AT91C_AIC_SRCTYPE_HIGH_LEVEL | AT91SAM7_SPI0_PRIORITY,
SPI0IrqHandler);
#endif
#if AT91SAM7_SPI_USE_SPI1
spiObjectInit(&SPID2);
SPID2.spi = AT91C_BASE_SPI1;
spi_init(AT91C_BASE_SPI1);
AT91C_BASE_PIOA->PIO_PDR = SPI1_MISO | SPI1_MOSI | SPI1_SCK;
AT91C_BASE_PIOA->PIO_BSR = SPI1_MISO | SPI1_MOSI | SPI1_SCK;
AT91C_BASE_PIOA->PIO_PPUDR = SPI1_MISO | SPI1_MOSI | SPI1_SCK;
AIC_ConfigureIT(AT91C_ID_SPI1,
AT91C_AIC_SRCTYPE_HIGH_LEVEL | AT91SAM7_SPI1_PRIORITY,
SPI1IrqHandler);
#endif
}
/**
* @brief Configures and activates the SPI peripheral.
*
* @param[in] spip pointer to the @p SPIDriver object
*
* @notapi
*/
void spi_lld_start(SPIDriver *spip) {
if (spip->state == SPI_STOP) {
#if AT91SAM7_SPI_USE_SPI0
if (&SPID1 == spip) {
/* Clock activation.*/
AT91C_BASE_PMC->PMC_PCER = (1 << AT91C_ID_SPI0);
/* Enables associated interrupt vector.*/
AIC_EnableIT(AT91C_ID_SPI0);
}
#endif
#if AT91SAM7_SPI_USE_SPI1
if (&SPID2 == spip) {
/* Clock activation.*/
AT91C_BASE_PMC->PMC_PCER = (1 << AT91C_ID_SPI1);
/* Enables associated interrupt vector.*/
AIC_EnableIT(AT91C_ID_SPI1);
}
#endif
}
/* Configuration.*/
spip->spi->SPI_CSR[0] = spip->config->csr;
}
/**
* @brief Deactivates the SPI peripheral.
*
* @param[in] spip pointer to the @p SPIDriver object
*
* @notapi
*/
void spi_lld_stop(SPIDriver *spip) {
if (spip->state != SPI_STOP) {
#if AT91SAM7_SPI_USE_SPI0
if (&SPID1 == spip) {
AT91C_BASE_PMC->PMC_PCDR = (1 << AT91C_ID_SPI0);
AIC_DisableIT(AT91C_ID_SPI0);
}
#endif
#if AT91SAM7_SPI_USE_SPI1
if (&SPID1 == spip) {
AT91C_BASE_PMC->PMC_PCDR = (1 << AT91C_ID_SPI1);
AIC_DisableIT(AT91C_ID_SPI0);
}
#endif
}
}
/**
* @brief Asserts the slave select signal and prepares for transfers.
*
* @param[in] spip pointer to the @p SPIDriver object
*
* @notapi
*/
void spi_lld_select(SPIDriver *spip) {
palClearPad(spip->config->ssport, spip->config->sspad);
}
/**
* @brief Deasserts the slave select signal.
* @details The previously selected peripheral is unselected.
*
* @param[in] spip pointer to the @p SPIDriver object
*
* @notapi
*/
void spi_lld_unselect(SPIDriver *spip) {
palSetPad(spip->config->ssport, spip->config->sspad);
}
/**
* @brief Ignores data on the SPI bus.
* @details This function transmits a series of idle words on the SPI bus and
* ignores the received data. This function can be invoked even
* when a slave select signal has not been yet asserted.
*
* @param[in] spip pointer to the @p SPIDriver object
* @param[in] n number of words to be ignored
*
* @notapi
*/
void spi_lld_ignore(SPIDriver *spip, size_t n) {
spip->spi->SPI_TCR = n;
spip->spi->SPI_RCR = n;
spip->spi->SPI_TPR = (AT91_REG)idle_buf;
spip->spi->SPI_RPR = (AT91_REG)idle_buf;
spip->spi->SPI_IER = AT91C_SPI_ENDRX;
spip->spi->SPI_CR = AT91C_SPI_SPIEN;
spip->spi->SPI_PTCR = AT91C_PDC_RXTEN | AT91C_PDC_TXTEN;
}
/**
* @brief Exchanges data on the SPI bus.
* @details This function performs a simultaneous transmit/receive operation.
* @note The buffers are organized as uint8_t arrays.
*
* @param[in] spip pointer to the @p SPIDriver object
* @param[in] n number of words to be exchanged
* @param[in] txbuf the pointer to the transmit buffer
* @param[out] rxbuf the pointer to the receive buffer
*
* @notapi
*/
void spi_lld_exchange(SPIDriver *spip, size_t n,
const void *txbuf, void *rxbuf) {
spip->spi->SPI_TCR = n;
spip->spi->SPI_RCR = n;
spip->spi->SPI_TPR = (AT91_REG)txbuf;
spip->spi->SPI_RPR = (AT91_REG)rxbuf;
spip->spi->SPI_IER = AT91C_SPI_ENDRX;
spip->spi->SPI_CR = AT91C_SPI_SPIEN;
spip->spi->SPI_PTCR = AT91C_PDC_RXTEN | AT91C_PDC_TXTEN;
}
/**
* @brief Sends data over the SPI bus.
* @note The buffers are organized as uint8_t arrays.
*
* @param[in] spip pointer to the @p SPIDriver object
* @param[in] n number of words to send
* @param[in] txbuf the pointer to the transmit buffer
*
* @notapi
*/
void spi_lld_send(SPIDriver *spip, size_t n, const void *txbuf) {
spip->spi->SPI_TCR = n;
spip->spi->SPI_RCR = n;
spip->spi->SPI_TPR = (AT91_REG)txbuf;
spip->spi->SPI_RPR = (AT91_REG)idle_buf;
spip->spi->SPI_IER = AT91C_SPI_ENDRX;
spip->spi->SPI_CR = AT91C_SPI_SPIEN;
spip->spi->SPI_PTCR = AT91C_PDC_RXTEN | AT91C_PDC_TXTEN;
}
/**
* @brief Receives data from the SPI bus.
* @note The buffers are organized as uint8_t arrays.
*
* @param[in] spip pointer to the @p SPIDriver object
* @param[in] n number of words to receive
* @param[out] rxbuf the pointer to the receive buffer
*
* @notapi
*/
void spi_lld_receive(SPIDriver *spip, size_t n, void *rxbuf) {
spip->spi->SPI_TCR = n;
spip->spi->SPI_RCR = n;
spip->spi->SPI_TPR = (AT91_REG)idle_buf;
spip->spi->SPI_RPR = (AT91_REG)rxbuf;
spip->spi->SPI_IER = AT91C_SPI_ENDRX;
spip->spi->SPI_CR = AT91C_SPI_SPIEN;
spip->spi->SPI_PTCR = AT91C_PDC_RXTEN | AT91C_PDC_TXTEN;
}
/**
* @brief Exchanges one frame using a polled wait.
* @details This synchronous function exchanges one frame using a polled
* synchronization method. This function is useful when exchanging
* small amount of data on high speed channels, usually in this
* situation is much more efficient just wait for completion using
* polling than suspending the thread waiting for an interrupt.
*
* @param[in] spip pointer to the @p SPIDriver object
* @param[in] frame the data frame to send over the SPI bus
* @return The received data frame from the SPI bus.
*/
uint16_t spi_lld_polled_exchange(SPIDriver *spip, uint16_t frame) {
spip->spi->SPI_CR = AT91C_SPI_SPIEN;
spip->spi->SPI_TDR = frame;
while ((spip->spi->SPI_SR & AT91C_SPI_RDRF) == 0)
;
return spip->spi->SPI_RDR;
}
#endif /* HAL_USE_SPI */
/** @} */
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