402 lines
13 KiB
C
402 lines
13 KiB
C
/*
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ChibiOS/RT - Copyright (C) 2006,2007,2008,2009,2010,
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2011,2012,2013 Giovanni Di Sirio.
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This file is part of ChibiOS/RT.
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ChibiOS/RT is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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ChibiOS/RT is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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/**
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* @file AT91SAM7/spi_lld.c
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* @brief AT91SAM7 low level SPI driver code.
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*
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* @addtogroup SPI
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* @{
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*/
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#include "ch.h"
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#include "hal.h"
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#if HAL_USE_SPI || defined(__DOXYGEN__)
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/*===========================================================================*/
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/* Driver exported variables. */
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/*===========================================================================*/
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#if AT91SAM7_SPI_USE_SPI0 || defined(__DOXYGEN__)
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/** @brief SPI1 driver identifier.*/
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SPIDriver SPID1;
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#endif
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#if AT91SAM7_SPI_USE_SPI1 || defined(__DOXYGEN__)
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/** @brief SPI2 driver identifier.*/
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SPIDriver SPID2;
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#endif
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/*===========================================================================*/
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/* Driver local variables and types. */
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/*===========================================================================*/
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/**
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* @brief Idle line value.
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* @details This thing's DMA apparently does not allow to *not* increment
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* the memory pointer so a buffer filled with ones is required
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* somewhere.
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* @note This buffer size also limits the maximum transfer size, 512B,
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* for @p spiReceive() and @p spiIgnore(). @p spiSend() and
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* @p spiExchange are not affected.
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*/
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static const uint16_t idle_buf[] = {
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0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
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0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
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0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
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0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
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0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
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0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
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0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
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0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
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0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
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0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
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0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
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0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
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0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
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0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
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0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
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0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
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0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
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0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
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0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
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0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
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0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
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0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
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0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
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0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
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0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
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0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
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0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
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0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
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0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
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0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
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0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
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0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF
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};
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/*===========================================================================*/
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/* Driver local functions. */
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/*===========================================================================*/
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/**
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* @brief Initializes a SPI device.
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*/
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static void spi_init(AT91PS_SPI spi) {
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/* Software reset must be written twice (errata for revision B parts).*/
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spi->SPI_CR = AT91C_SPI_SWRST;
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spi->SPI_CR = AT91C_SPI_SWRST;
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spi->SPI_RCR = 0;
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spi->SPI_RNCR = 0;
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spi->SPI_TCR = 0;
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spi->SPI_TNCR = 0;
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spi->SPI_PTCR = AT91C_PDC_RXTDIS | AT91C_PDC_TXTDIS;
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spi->SPI_MR = AT91C_SPI_MSTR | AT91C_SPI_MODFDIS;
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}
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#if defined(__GNUC__)
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__attribute__((noinline))
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#endif
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/**
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* @brief Shared interrupt handling code.
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*
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* @param[in] spip pointer to the @p SPIDriver object
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*/
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static void spi_lld_serve_interrupt(SPIDriver *spip) {
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uint32_t sr = spip->spi->SPI_SR;
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if ((sr & AT91C_SPI_ENDRX) != 0) {
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(void)spip->spi->SPI_RDR; /* Clears eventual overflow.*/
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spip->spi->SPI_PTCR = AT91C_PDC_RXTDIS |
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AT91C_PDC_TXTDIS; /* PDC disabled. */
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spip->spi->SPI_IDR = AT91C_SPI_ENDRX; /* Interrupt disabled. */
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spip->spi->SPI_CR = AT91C_SPI_SPIDIS; /* SPI disabled. */
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/* Portable SPI ISR code defined in the high level driver, note, it is
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a macro.*/
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_spi_isr_code(spip);
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}
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}
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/*===========================================================================*/
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/* Driver interrupt handlers. */
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/*===========================================================================*/
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#if AT91SAM7_SPI_USE_SPI0 || defined(__DOXYGEN__)
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/**
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* @brief SPI0 interrupt handler.
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*
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* @isr
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*/
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CH_IRQ_HANDLER(SPI0IrqHandler) {
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CH_IRQ_PROLOGUE();
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spi_lld_serve_interrupt(&SPID1);
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AT91C_BASE_AIC->AIC_EOICR = 0;
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CH_IRQ_EPILOGUE();
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}
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#endif
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#if AT91SAM7_SPI_USE_SPI1 || defined(__DOXYGEN__)
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/**
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* @brief SPI1 interrupt handler.
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*
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* @isr
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*/
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CH_IRQ_HANDLER(SPI1IrqHandler) {
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CH_IRQ_PROLOGUE();
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spi_lld_serve_interrupt(&SPID2);
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AT91C_BASE_AIC->AIC_EOICR = 0;
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CH_IRQ_EPILOGUE();
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}
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#endif
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/*===========================================================================*/
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/* Driver exported functions. */
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/*===========================================================================*/
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/**
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* @brief Low level SPI driver initialization.
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*
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* @notapi
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*/
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void spi_lld_init(void) {
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#if AT91SAM7_SPI_USE_SPI0
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spiObjectInit(&SPID1);
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SPID1.spi = AT91C_BASE_SPI0;
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spi_init(AT91C_BASE_SPI0);
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AT91C_BASE_PIOA->PIO_PDR = SPI0_MISO | SPI0_MOSI | SPI0_SCK;
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AT91C_BASE_PIOA->PIO_ASR = SPI0_MISO | SPI0_MOSI | SPI0_SCK;
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AT91C_BASE_PIOA->PIO_PPUDR = SPI0_MISO | SPI0_MOSI | SPI0_SCK;
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AIC_ConfigureIT(AT91C_ID_SPI0,
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AT91C_AIC_SRCTYPE_HIGH_LEVEL | AT91SAM7_SPI0_PRIORITY,
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SPI0IrqHandler);
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#endif
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#if AT91SAM7_SPI_USE_SPI1
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spiObjectInit(&SPID2);
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SPID2.spi = AT91C_BASE_SPI1;
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spi_init(AT91C_BASE_SPI1);
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AT91C_BASE_PIOA->PIO_PDR = SPI1_MISO | SPI1_MOSI | SPI1_SCK;
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AT91C_BASE_PIOA->PIO_BSR = SPI1_MISO | SPI1_MOSI | SPI1_SCK;
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AT91C_BASE_PIOA->PIO_PPUDR = SPI1_MISO | SPI1_MOSI | SPI1_SCK;
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AIC_ConfigureIT(AT91C_ID_SPI1,
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AT91C_AIC_SRCTYPE_HIGH_LEVEL | AT91SAM7_SPI1_PRIORITY,
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SPI1IrqHandler);
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#endif
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}
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/**
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* @brief Configures and activates the SPI peripheral.
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*
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* @param[in] spip pointer to the @p SPIDriver object
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*
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* @notapi
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*/
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void spi_lld_start(SPIDriver *spip) {
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if (spip->state == SPI_STOP) {
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#if AT91SAM7_SPI_USE_SPI0
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if (&SPID1 == spip) {
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/* Clock activation.*/
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AT91C_BASE_PMC->PMC_PCER = (1 << AT91C_ID_SPI0);
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/* Enables associated interrupt vector.*/
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AIC_EnableIT(AT91C_ID_SPI0);
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}
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#endif
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#if AT91SAM7_SPI_USE_SPI1
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if (&SPID2 == spip) {
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/* Clock activation.*/
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AT91C_BASE_PMC->PMC_PCER = (1 << AT91C_ID_SPI1);
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/* Enables associated interrupt vector.*/
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AIC_EnableIT(AT91C_ID_SPI1);
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}
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#endif
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}
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/* Configuration.*/
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spip->spi->SPI_CSR[0] = spip->config->csr;
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}
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/**
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* @brief Deactivates the SPI peripheral.
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*
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* @param[in] spip pointer to the @p SPIDriver object
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*
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* @notapi
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*/
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void spi_lld_stop(SPIDriver *spip) {
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if (spip->state != SPI_STOP) {
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#if AT91SAM7_SPI_USE_SPI0
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if (&SPID1 == spip) {
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AT91C_BASE_PMC->PMC_PCDR = (1 << AT91C_ID_SPI0);
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AIC_DisableIT(AT91C_ID_SPI0);
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}
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#endif
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#if AT91SAM7_SPI_USE_SPI1
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if (&SPID1 == spip) {
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AT91C_BASE_PMC->PMC_PCDR = (1 << AT91C_ID_SPI1);
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AIC_DisableIT(AT91C_ID_SPI0);
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}
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#endif
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}
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}
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/**
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* @brief Asserts the slave select signal and prepares for transfers.
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*
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* @param[in] spip pointer to the @p SPIDriver object
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*
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* @notapi
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*/
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void spi_lld_select(SPIDriver *spip) {
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palClearPad(spip->config->ssport, spip->config->sspad);
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}
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/**
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* @brief Deasserts the slave select signal.
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* @details The previously selected peripheral is unselected.
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*
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* @param[in] spip pointer to the @p SPIDriver object
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*
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* @notapi
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*/
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void spi_lld_unselect(SPIDriver *spip) {
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palSetPad(spip->config->ssport, spip->config->sspad);
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}
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/**
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* @brief Ignores data on the SPI bus.
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* @details This function transmits a series of idle words on the SPI bus and
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* ignores the received data. This function can be invoked even
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* when a slave select signal has not been yet asserted.
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*
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* @param[in] spip pointer to the @p SPIDriver object
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* @param[in] n number of words to be ignored
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*
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* @notapi
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*/
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void spi_lld_ignore(SPIDriver *spip, size_t n) {
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spip->spi->SPI_TCR = n;
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spip->spi->SPI_RCR = n;
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spip->spi->SPI_TPR = (AT91_REG)idle_buf;
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spip->spi->SPI_RPR = (AT91_REG)idle_buf;
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spip->spi->SPI_IER = AT91C_SPI_ENDRX;
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spip->spi->SPI_CR = AT91C_SPI_SPIEN;
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spip->spi->SPI_PTCR = AT91C_PDC_RXTEN | AT91C_PDC_TXTEN;
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}
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/**
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* @brief Exchanges data on the SPI bus.
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* @details This function performs a simultaneous transmit/receive operation.
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* @note The buffers are organized as uint8_t arrays.
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*
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* @param[in] spip pointer to the @p SPIDriver object
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* @param[in] n number of words to be exchanged
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* @param[in] txbuf the pointer to the transmit buffer
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* @param[out] rxbuf the pointer to the receive buffer
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*
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* @notapi
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*/
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void spi_lld_exchange(SPIDriver *spip, size_t n,
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const void *txbuf, void *rxbuf) {
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spip->spi->SPI_TCR = n;
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spip->spi->SPI_RCR = n;
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spip->spi->SPI_TPR = (AT91_REG)txbuf;
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spip->spi->SPI_RPR = (AT91_REG)rxbuf;
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spip->spi->SPI_IER = AT91C_SPI_ENDRX;
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spip->spi->SPI_CR = AT91C_SPI_SPIEN;
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spip->spi->SPI_PTCR = AT91C_PDC_RXTEN | AT91C_PDC_TXTEN;
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}
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/**
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* @brief Sends data over the SPI bus.
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* @note The buffers are organized as uint8_t arrays.
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*
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* @param[in] spip pointer to the @p SPIDriver object
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* @param[in] n number of words to send
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* @param[in] txbuf the pointer to the transmit buffer
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*
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* @notapi
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*/
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void spi_lld_send(SPIDriver *spip, size_t n, const void *txbuf) {
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spip->spi->SPI_TCR = n;
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spip->spi->SPI_RCR = n;
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spip->spi->SPI_TPR = (AT91_REG)txbuf;
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spip->spi->SPI_RPR = (AT91_REG)idle_buf;
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spip->spi->SPI_IER = AT91C_SPI_ENDRX;
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spip->spi->SPI_CR = AT91C_SPI_SPIEN;
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spip->spi->SPI_PTCR = AT91C_PDC_RXTEN | AT91C_PDC_TXTEN;
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}
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/**
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* @brief Receives data from the SPI bus.
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* @note The buffers are organized as uint8_t arrays.
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*
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* @param[in] spip pointer to the @p SPIDriver object
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* @param[in] n number of words to receive
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* @param[out] rxbuf the pointer to the receive buffer
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*
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* @notapi
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*/
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void spi_lld_receive(SPIDriver *spip, size_t n, void *rxbuf) {
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spip->spi->SPI_TCR = n;
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spip->spi->SPI_RCR = n;
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spip->spi->SPI_TPR = (AT91_REG)idle_buf;
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spip->spi->SPI_RPR = (AT91_REG)rxbuf;
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spip->spi->SPI_IER = AT91C_SPI_ENDRX;
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spip->spi->SPI_CR = AT91C_SPI_SPIEN;
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spip->spi->SPI_PTCR = AT91C_PDC_RXTEN | AT91C_PDC_TXTEN;
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}
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/**
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* @brief Exchanges one frame using a polled wait.
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* @details This synchronous function exchanges one frame using a polled
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* synchronization method. This function is useful when exchanging
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* small amount of data on high speed channels, usually in this
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* situation is much more efficient just wait for completion using
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* polling than suspending the thread waiting for an interrupt.
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*
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* @param[in] spip pointer to the @p SPIDriver object
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* @param[in] frame the data frame to send over the SPI bus
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* @return The received data frame from the SPI bus.
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*/
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uint16_t spi_lld_polled_exchange(SPIDriver *spip, uint16_t frame) {
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spip->spi->SPI_CR = AT91C_SPI_SPIEN;
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spip->spi->SPI_TDR = frame;
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while ((spip->spi->SPI_SR & AT91C_SPI_RDRF) == 0)
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;
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return spip->spi->SPI_RDR;
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}
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#endif /* HAL_USE_SPI */
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/** @} */
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