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

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/*
ChibiOS/RT - Copyright (C) 2006-2013 Giovanni Di Sirio
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
/**
* @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 and types. */
/*===========================================================================*/
/**
* @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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