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tinySA/os/hal/platforms/LPC43xx/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 LPC43xx/spi_lld.c
* @brief LPC43xx low level SPI driver code.
*
* @addtogroup SPI
* @{
*/
#include "ch.h"
#include "hal.h"
#if HAL_USE_SPI || defined(__DOXYGEN__)
/*===========================================================================*/
/* Driver exported variables. */
/*===========================================================================*/
#if LPC_SPI_USE_SSP0 || defined(__DOXYGEN__)
/** @brief SPI1 driver identifier.*/
SPIDriver SPID1;
#endif
#if LPC_SPI_USE_SSP1 || defined(__DOXYGEN__)
/** @brief SPI2 driver identifier.*/
SPIDriver SPID2;
#endif
/*===========================================================================*/
/* Driver local variables and types. */
/*===========================================================================*/
/*===========================================================================*/
/* Driver local functions. */
/*===========================================================================*/
/**
* @brief Preloads the transmit FIFO.
*
* @param[in] spip pointer to the @p SPIDriver object
*/
static void ssp_fifo_preload(SPIDriver *spip) {
LPC_SSPn_Type *ssp = spip->ssp;
uint32_t n = spip->txcnt > LPC_SSP_FIFO_DEPTH ?
LPC_SSP_FIFO_DEPTH : spip->txcnt;
while(((ssp->SR & SR_TNF) != 0) && (n > 0)) {
if (spip->txptr != NULL) {
if ((ssp->CR0 & CR0_DSSMASK) > CR0_DSS8BIT) {
const uint16_t *p = spip->txptr;
ssp->DR = *p++;
spip->txptr = p;
}
else {
const uint8_t *p = spip->txptr;
ssp->DR = *p++;
spip->txptr = p;
}
}
else
ssp->DR = 0xFFFFFFFF;
n--;
spip->txcnt--;
}
}
/**
* @brief Common IRQ handler.
*
* @param[in] spip pointer to the @p SPIDriver object
*/
static void spi_serve_interrupt(SPIDriver *spip) {
LPC_SSPn_Type *ssp = spip->ssp;
if ((ssp->MIS & MIS_ROR) != 0) {
/* The overflow condition should never happen because priority is given
to receive but a hook macro is provided anyway...*/
LPC_SPI_SSP_ERROR_HOOK(spip);
}
ssp->ICR = ICR_RT | ICR_ROR;
while ((ssp->SR & SR_RNE) != 0) {
if (spip->rxptr != NULL) {
if ((ssp->CR0 & CR0_DSSMASK) > CR0_DSS8BIT) {
uint16_t *p = spip->rxptr;
*p++ = ssp->DR;
spip->rxptr = p;
}
else {
uint8_t *p = spip->rxptr;
*p++ = ssp->DR;
spip->rxptr = p;
}
}
else
(void)ssp->DR;
if (--spip->rxcnt == 0) {
chDbgAssert(spip->txcnt == 0,
"spi_serve_interrupt(), #1", "counter out of synch");
/* Stops the IRQ sources.*/
ssp->IMSC = 0;
/* Portable SPI ISR code defined in the high level driver, note, it is
a macro.*/
_spi_isr_code(spip);
return;
}
}
ssp_fifo_preload(spip);
if (spip->txcnt == 0)
ssp->IMSC = IMSC_ROR | IMSC_RT | IMSC_RX;
}
/*===========================================================================*/
/* Driver interrupt handlers. */
/*===========================================================================*/
#if LPC_SPI_USE_SSP0 || defined(__DOXYGEN__)
/**
* @brief SSP0 interrupt handler.
*
* @isr
*/
CH_IRQ_HANDLER(Vector98) {
CH_IRQ_PROLOGUE();
spi_serve_interrupt(&SPID1);
CH_IRQ_EPILOGUE();
}
#endif
#if LPC_SPI_USE_SSP1 || defined(__DOXYGEN__)
/**
* @brief SSP1 interrupt handler.
*
* @isr
*/
CH_IRQ_HANDLER(Vector9C) {
CH_IRQ_PROLOGUE();
spi_serve_interrupt(&SPID2);
CH_IRQ_EPILOGUE();
}
#endif
/*===========================================================================*/
/* Driver exported functions. */
/*===========================================================================*/
/**
* @brief Low level SPI driver initialization.
*
* @notapi
*/
void spi_lld_init(void) {
#if LPC_SPI_USE_SSP0
spiObjectInit(&SPID1);
SPID1.ssp = LPC_SSP0;
#endif /* LPC_SPI_USE_SSP0 */
#if LPC_SPI_USE_SSP1
spiObjectInit(&SPID2);
SPID2.ssp = LPC_SSP1;
#endif /* LPC_SPI_USE_SSP0 */
}
/**
* @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) {
/* Clock activation.*/
#if LPC_SPI_USE_SSP0
if (&SPID1 == spip) {
LPC_CCU2->CLK_APB0_SSP0_CFG = 1;
nvicEnableVector(SSP0_IRQn,
CORTEX_PRIORITY_MASK(LPC_SPI_SSP0_IRQ_PRIORITY));
}
#endif
#if LPC_SPI_USE_SSP1
if (&SPID2 == spip) {
LPC_CCU2->CLK_APB2_SSP1_CFG= 1;
nvicEnableVector(SSP1_IRQn,
CORTEX_PRIORITY_MASK(LPC_SPI_SSP1_IRQ_PRIORITY));
}
#endif
}
/* Configuration.*/
spip->ssp->CR1 = 0;
spip->ssp->ICR = ICR_RT | ICR_ROR;
spip->ssp->CR0 = spip->config->cr0;
spip->ssp->CPSR = spip->config->cpsr;
spip->ssp->CR1 = CR1_SSE;
}
/**
* @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) {
spip->ssp->CR1 = 0;
spip->ssp->CR0 = 0;
spip->ssp->CPSR = 0;
#if LPC_SPI_USE_SSP0
if (&SPID1 == spip) {
LPC_CCU2->CLK_APB0_SSP0_CFG = 0;
nvicDisableVector(SSP0_IRQn);
}
#endif
#if LPC_SPI_USE_SSP1
if (&SPID2 == spip) {
LPC_CCU2->CLK_APB2_SSP1_CFG= 0;
nvicDisableVector(SSP1_IRQn);
}
#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->rxptr = NULL;
spip->txptr = NULL;
spip->rxcnt = spip->txcnt = n;
ssp_fifo_preload(spip);
spip->ssp->IMSC = IMSC_ROR | IMSC_RT | IMSC_TX | IMSC_RX;
}
/**
* @brief Exchanges data on the SPI bus.
* @details This asynchronous function starts a simultaneous transmit/receive
* operation.
* @post At the end of the operation the configured callback is invoked.
* @note The buffers are organized as uint8_t arrays for data sizes below or
* equal to 8 bits else it is organized as uint16_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->rxptr = rxbuf;
spip->txptr = txbuf;
spip->rxcnt = spip->txcnt = n;
ssp_fifo_preload(spip);
spip->ssp->IMSC = IMSC_ROR | IMSC_RT | IMSC_TX | IMSC_RX;
}
/**
* @brief Sends data over the SPI bus.
* @details This asynchronous function starts a transmit operation.
* @post At the end of the operation the configured callback is invoked.
* @note The buffers are organized as uint8_t arrays for data sizes below or
* equal to 8 bits else it is organized as uint16_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->rxptr = NULL;
spip->txptr = txbuf;
spip->rxcnt = spip->txcnt = n;
ssp_fifo_preload(spip);
spip->ssp->IMSC = IMSC_ROR | IMSC_RT | IMSC_TX | IMSC_RX;
}
/**
* @brief Receives data from the SPI bus.
* @details This asynchronous function starts a receive operation.
* @post At the end of the operation the configured callback is invoked.
* @note The buffers are organized as uint8_t arrays for data sizes below or
* equal to 8 bits else it is organized as uint16_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->rxptr = rxbuf;
spip->txptr = NULL;
spip->rxcnt = spip->txcnt = n;
ssp_fifo_preload(spip);
spip->ssp->IMSC = IMSC_ROR | IMSC_RT | IMSC_TX | IMSC_RX;
}
/**
* @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->ssp->DR = (uint32_t)frame;
while ((spip->ssp->SR & SR_RNE) == 0)
;
return (uint16_t)spip->ssp->DR;
}
#endif /* HAL_USE_SPI */
/** @} */
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