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nuttx/arch/arm/src/samv7/sam_spi.c

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/****************************************************************************
* arch/arm/src/samv7/sam_spi.c
*
* Copyright (C) 2015=2016 Gregory Nutt. All rights reserved.
* Authors: Gregory Nutt <gnutt@nuttx.org>
* Diego Sanchez <dsanchez@nx-engineering.com>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS 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.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <sys/types.h>
#include <stdint.h>
#include <stdbool.h>
#include <stdlib.h>
#include <string.h>
#include <semaphore.h>
#include <errno.h>
#include <assert.h>
#include <debug.h>
#include <arch/board/board.h>
#include <nuttx/irq.h>
#include <nuttx/arch.h>
#include <nuttx/wdog.h>
#include <nuttx/clock.h>
#include <nuttx/spi/spi.h>
#include "up_internal.h"
#include "up_arch.h"
#include "cache.h"
#include "sam_gpio.h"
#include "sam_xdmac.h"
#include "sam_periphclks.h"
#include "sam_spi.h"
#include "chip/sam_pmc.h"
#include "chip/sam_xdmac.h"
#include "chip/sam_spi.h"
#include "chip/sam_pinmap.h"
#ifdef CONFIG_SAMV7_SPI_MASTER
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/* Configuration ************************************************************/
/* When SPI DMA is enabled, small DMA transfers will still be performed by
* polling logic. But we need a threshold value to determine what is small.
* That value is provided by CONFIG_SAMV7_SPI_DMATHRESHOLD.
*/
#ifndef CONFIG_SAMV7_SPI_DMATHRESHOLD
# define CONFIG_SAMV7_SPI_DMATHRESHOLD 4
#endif
#ifdef CONFIG_SAMV7_SPI_DMA
# if defined(CONFIG_SAMV7_SPI0_MASTER) && defined(CONFIG_SAMV7_XDMAC)
# define SAMV7_SPI0_DMA true
# else
# define SAMV7_SPI0_DMA false
# endif
# if defined(CONFIG_SAMV7_SPI1_MASTER) && defined(CONFIG_SAMV7_XDMAC)
# define SAMV7_SPI1_DMA true
# else
# define SAMV7_SPI1_DMA false
# endif
#endif
#ifndef CONFIG_SAMV7_SPI_DMA
# undef CONFIG_SAMV7_SPI_DMADEBUG
#endif
/* Clocking *****************************************************************/
/* The SPI Baud rate clock is generated by dividing the peripheral clock by
* a value between 1 and 255
*/
#define SAM_SPI_CLOCK BOARD_MCK_FREQUENCY /* Frequency of the main clock */
/* DMA timeout. The value is not critical; we just don't want the system to
* hang in the event that a DMA does not finish. This is set to
*/
#define DMA_TIMEOUT_MS (800)
#define DMA_TIMEOUT_TICKS MSEC2TICK(DMA_TIMEOUT_MS)
/* Debug *******************************************************************/
/* Check if SPI debug is enabled (non-standard.. no support in
* include/debug.h
*/
#ifndef CONFIG_DEBUG
# undef CONFIG_DEBUG_VERBOSE
# undef CONFIG_DEBUG_SPI
# undef CONFIG_SAMV7_SPI_DMADEBUG
# undef CONFIG_SAMV7_SPI_REGDEBUG
#endif
#ifndef CONFIG_DEBUG_DMA
# undef CONFIG_SAMV7_SPI_DMADEBUG
#endif
#ifdef CONFIG_DEBUG_SPI
# define spidbg lldbg
# ifdef CONFIG_DEBUG_VERBOSE
# define spivdbg lldbg
# else
# define spivdbg(x...)
# endif
#else
# define spidbg(x...)
# define spivdbg(x...)
#endif
#define DMA_INITIAL 0
#define DMA_AFTER_SETUP 1
#define DMA_AFTER_START 2
#define DMA_CALLBACK 3
#define DMA_TIMEOUT 3
#define DMA_END_TRANSFER 4
#define DMA_NSAMPLES 5
/****************************************************************************
* Private Types
****************************************************************************/
/* The state of the one SPI chip select */
struct sam_spics_s
{
struct spi_dev_s spidev; /* Externally visible part of the SPI interface */
uint32_t frequency; /* Requested clock frequency */
uint32_t actual; /* Actual clock frequency */
uint8_t mode; /* Mode 0,1,2,3 */
uint8_t nbits; /* Width of word in bits (8 to 16) */
#if defined(CONFIG_SAMV7_SPI0_MASTER) || defined(CONFIG_SAMV7_SPI1_MASTER)
uint8_t spino; /* SPI controller number (0 or 1) */
#endif
uint8_t cs; /* Chip select number */
#ifdef CONFIG_SAMV7_SPI_DMA
bool candma; /* DMA is supported */
sem_t dmawait; /* Used to wait for DMA completion */
WDOG_ID dmadog; /* Watchdog that handles DMA timeouts */
int result; /* DMA result */
DMA_HANDLE rxdma; /* SPI RX DMA handle */
DMA_HANDLE txdma; /* SPI TX DMA handle */
#endif
/* Debug stuff */
#ifdef CONFIG_SAMV7_SPI_DMADEBUG
struct sam_dmaregs_s rxdmaregs[DMA_NSAMPLES];
struct sam_dmaregs_s txdmaregs[DMA_NSAMPLES];
#endif
};
/* Type of board-specific SPI status function */
typedef void (*select_t)(enum spi_dev_e devid, bool selected);
/* Chip select register offsets */
/* The overall state of one SPI controller */
struct sam_spidev_s
{
uint32_t base; /* SPI controller register base address */
sem_t spisem; /* Assures mutually exclusive access to SPI */
select_t select; /* SPI select call-out */
bool initialized; /* TRUE: Controller has been initialized */
#ifdef CONFIG_SAMV7_SPI_DMA
uint8_t pid; /* SPI peripheral ID */
#endif
/* Debug stuff */
#ifdef CONFIG_SAMV7_SPI_REGDEBUG
bool wrlast; /* Last was a write */
uint32_t addresslast; /* Last address */
uint32_t valuelast; /* Last value */
int ntimes; /* Number of times */
#endif
};
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
/* Helpers */
#ifdef CONFIG_SAMV7_SPI_REGDEBUG
static bool spi_checkreg(struct sam_spidev_s *spi, bool wr,
uint32_t value, uint32_t address);
#else
# define spi_checkreg(spi,wr,value,address) (false)
#endif
static inline uint32_t spi_getreg(struct sam_spidev_s *spi,
unsigned int offset);
static inline void spi_putreg(struct sam_spidev_s *spi, uint32_t value,
unsigned int offset);
static inline struct sam_spidev_s *spi_device(struct sam_spics_s *spics);
#if defined(CONFIG_DEBUG_SPI) && defined(CONFIG_DEBUG_VERBOSE)
static void spi_dumpregs(struct sam_spidev_s *spi, const char *msg);
#else
# define spi_dumpregs(spi,msg)
#endif
static inline void spi_flush(struct sam_spidev_s *spi);
static inline uint32_t spi_cs2pcs(struct sam_spics_s *spics);
/* DMA support */
#ifdef CONFIG_SAMV7_SPI_DMA
#ifdef CONFIG_SAMV7_SPI_DMADEBUG
# define spi_rxdma_sample(s,i) sam_dmasample((s)->rxdma, &(s)->rxdmaregs[i])
# define spi_txdma_sample(s,i) sam_dmasample((s)->txdma, &(s)->txdmaregs[i])
static void spi_dma_sampleinit(struct sam_spics_s *spics);
static void spi_dma_sampledone(struct sam_spics_s *spics);
#else
# define spi_rxdma_sample(s,i)
# define spi_txdma_sample(s,i)
# define spi_dma_sampleinit(s)
# define spi_dma_sampledone(s)
#endif
static void spi_rxcallback(DMA_HANDLE handle, void *arg, int result);
static void spi_txcallback(DMA_HANDLE handle, void *arg, int result);
static inline uintptr_t spi_regaddr(struct sam_spics_s *spics,
unsigned int offset);
#endif
/* SPI master methods */
static int spi_lock(struct spi_dev_s *dev, bool lock);
static void spi_select(struct spi_dev_s *dev, enum spi_dev_e devid,
bool selected);
static uint32_t spi_setfrequency(struct spi_dev_s *dev, uint32_t frequency);
static void spi_setmode(struct spi_dev_s *dev, enum spi_mode_e mode);
static void spi_setbits(struct spi_dev_s *dev, int nbits);
static uint16_t spi_send(struct spi_dev_s *dev, uint16_t ch);
#ifdef CONFIG_SAMV7_SPI_DMA
static void spi_exchange_nodma(struct spi_dev_s *dev,
const void *txbuffer, void *rxbuffer, size_t nwords);
#endif
static void spi_exchange(struct spi_dev_s *dev, const void *txbuffer,
void *rxbuffer, size_t nwords);
#ifndef CONFIG_SPI_EXCHANGE
static void spi_sndblock(struct spi_dev_s *dev,
const void *buffer, size_t nwords);
static void spi_recvblock(struct spi_dev_s *dev, void *buffer,
size_t nwords);
#endif
/****************************************************************************
* Private Data
****************************************************************************/
/* This array maps chip select numbers (0-3) to CSR register offsets */
static const uint8_t g_csroffset[4] =
{
SAM_SPI_CSR0_OFFSET, SAM_SPI_CSR1_OFFSET,
SAM_SPI_CSR2_OFFSET, SAM_SPI_CSR3_OFFSET
};
#ifdef CONFIG_SAMV7_SPI0_MASTER
/* SPI0 driver operations */
static const struct spi_ops_s g_spi0ops =
{
.lock = spi_lock,
.select = spi_select,
.setfrequency = spi_setfrequency,
.setmode = spi_setmode,
.setbits = spi_setbits,
#ifdef CONFIG_SPI_HWFEATURES
.hwfeatures = 0, /* Not supported */
#endif
.status = sam_spi0status,
#ifdef CONFIG_SPI_CMDDATA
.cmddata = sam_spi0cmddata,
#endif
.send = spi_send,
#ifdef CONFIG_SPI_EXCHANGE
.exchange = spi_exchange,
#else
.sndblock = spi_sndblock,
.recvblock = spi_recvblock,
#endif
.registercallback = 0, /* Not implemented */
};
/* This is the overall state of the SPI0 controller */
static struct sam_spidev_s g_spi0dev =
{
.base = SAM_SPI0_BASE,
.select = sam_spi0select,
#ifdef CONFIG_SAMV7_SPI_DMA
.pid = SAM_PID_SPI0,
#endif
};
#endif
#ifdef CONFIG_SAMV7_SPI1_MASTER
/* SPI1 driver operations */
static const struct spi_ops_s g_spi1ops =
{
.lock = spi_lock,
.select = spi_select,
.setfrequency = spi_setfrequency,
.setmode = spi_setmode,
.setbits = spi_setbits,
.status = sam_spi1status,
#ifdef CONFIG_SPI_CMDDATA
.cmddata = sam_spi1cmddata,
#endif
.send = spi_send,
#ifdef CONFIG_SPI_EXCHANGE
.exchange = spi_exchange,
#else
.sndblock = spi_sndblock,
.recvblock = spi_recvblock,
#endif
.registercallback = 0, /* Not implemented */
};
/* This is the overall state of the SPI0 controller */
static struct sam_spidev_s g_spi1dev =
{
.base = SAM_SPI1_BASE,
.select = sam_spi1select,
#ifdef CONFIG_SAMV7_SPI_DMA
.pid = SAM_PID_SPI1,
#endif
};
#endif
/****************************************************************************
* Public Data
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: spi_checkreg
*
* Description:
* Check if the current register access is a duplicate of the preceding.
*
* Input Parameters:
* value - The value to be written
* address - The address of the register to write to
*
* Returned Value:
* true: This is the first register access of this type.
* flase: This is the same as the preceding register access.
*
****************************************************************************/
#ifdef CONFIG_SAMV7_SPI_REGDEBUG
static bool spi_checkreg(struct sam_spidev_s *spi, bool wr, uint32_t value,
uint32_t address)
{
if (wr == spi->wrlast && /* Same kind of access? */
value == spi->valuelast && /* Same value? */
address == spi->addresslast) /* Same address? */
{
/* Yes, then just keep a count of the number of times we did this. */
spi->ntimes++;
return false;
}
else
{
/* Did we do the previous operation more than once? */
if (spi->ntimes > 0)
{
/* Yes... show how many times we did it */
lldbg("...[Repeats %d times]...\n", spi->ntimes);
}
/* Save information about the new access */
spi->wrlast = wr;
spi->valuelast = value;
spi->addresslast = address;
spi->ntimes = 0;
}
/* Return true if this is the first time that we have done this operation */
return true;
}
#endif
/****************************************************************************
* Name: spi_getreg
*
* Description:
* Read an SPI register
*
****************************************************************************/
static inline uint32_t spi_getreg(struct sam_spidev_s *spi,
unsigned int offset)
{
uint32_t address = spi->base + offset;
uint32_t value = getreg32(address);
#ifdef CONFIG_SAMV7_SPI_REGDEBUG
if (spi_checkreg(spi, false, value, address))
{
lldbg("%08x->%08x\n", address, value);
}
#endif
return value;
}
/****************************************************************************
* Name: spi_putreg
*
* Description:
* Write a value to an SPI register
*
****************************************************************************/
static inline void spi_putreg(struct sam_spidev_s *spi, uint32_t value,
unsigned int offset)
{
uint32_t address = spi->base + offset;
#ifdef CONFIG_SAMV7_SPI_REGDEBUG
if (spi_checkreg(spi, true, value, address))
{
lldbg("%08x<-%08x\n", address, value);
}
#endif
putreg32(value, address);
}
/****************************************************************************
* Name: spi_dumpregs
*
* Description:
* Dump the contents of all SPI registers
*
* Input Parameters:
* spi - The SPI controller to dump
* msg - Message to print before the register data
*
* Returned Value:
* None
*
****************************************************************************/
#if defined(CONFIG_DEBUG_SPI) && defined(CONFIG_DEBUG_VERBOSE)
static void spi_dumpregs(struct sam_spidev_s *spi, const char *msg)
{
spivdbg("%s:\n", msg);
spivdbg(" MR:%08x SR:%08x IMR:%08x\n",
getreg32(spi->base + SAM_SPI_MR_OFFSET),
getreg32(spi->base + SAM_SPI_SR_OFFSET),
getreg32(spi->base + SAM_SPI_IMR_OFFSET));
spivdbg(" CSR0:%08x CSR1:%08x CSR2:%08x CSR3:%08x\n",
getreg32(spi->base + SAM_SPI_CSR0_OFFSET),
getreg32(spi->base + SAM_SPI_CSR1_OFFSET),
getreg32(spi->base + SAM_SPI_CSR2_OFFSET),
getreg32(spi->base + SAM_SPI_CSR3_OFFSET));
spivdbg(" WPCR:%08x WPSR:%08x\n",
getreg32(spi->base + SAM_SPI_WPCR_OFFSET),
getreg32(spi->base + SAM_SPI_WPSR_OFFSET));
}
#endif
/****************************************************************************
* Name: spi_device
*
* Description:
* Given a chip select instance, return a pointer to the parent SPI
* controller instance.
*
****************************************************************************/
static inline struct sam_spidev_s *spi_device(struct sam_spics_s *spics)
{
#if defined(CONFIG_SAMV7_SPI0_MASTER) && defined(CONFIG_SAMV7_SPI1_MASTER)
return spics->spino ? &g_spi1dev : &g_spi0dev;
#elif defined(CONFIG_SAMV7_SPI0_MASTER)
return &g_spi0dev;
#else
return &g_spi1dev;
#endif
}
/****************************************************************************
* Name: spi_flush
*
* Description:
* Make sure that there are now dangling SPI transfer in progress
*
* Input Parameters:
* spi - SPI controller state
*
* Returned Value:
* None
*
****************************************************************************/
static inline void spi_flush(struct sam_spidev_s *spi)
{
/* Make sure the no TX activity is in progress... waiting if necessary */
while ((spi_getreg(spi, SAM_SPI_SR_OFFSET) & SPI_INT_TXEMPTY) == 0);
/* Then make sure that there is no pending RX data .. reading as
* discarding as necessary.
*/
while ((spi_getreg(spi, SAM_SPI_SR_OFFSET) & SPI_INT_RDRF) != 0)
{
(void)spi_getreg(spi, SAM_SPI_RDR_OFFSET);
}
}
/****************************************************************************
* Name: spi_cs2pcs
*
* Description:
* Map the chip select number to the bit-set PCS field used in the SPI
* registers. A chip select number is used for indexing and identifying
* chip selects. However, the chip select information is represented by
* a bit set in the SPI registers. This function maps those chip select
* numbers to the correct bit set:
*
* CS Returned Spec Effective
* No. PCS Value NPCS
* ---- -------- -------- --------
* 0 0000 xxx0 1110
* 1 0001 xx01 1101
* 2 0011 x011 1011
* 3 0111 0111 0111
*
* Input Parameters:
* spics - Device-specific state data
*
* Returned Value:
* None
*
****************************************************************************/
static inline uint32_t spi_cs2pcs(struct sam_spics_s *spics)
{
#ifndef CONFIG_SAMV7_SPI_CS_DECODING
return ((uint32_t)1 << (spics->cs)) - 1;
#else
return spics->cs;
#endif
}
/****************************************************************************
* Name: spi_dma_sampleinit
*
* Description:
* Initialize sampling of DMA registers (if CONFIG_SAMV7_SPI_DMADEBUG)
*
* Input Parameters:
* spics - Chip select doing the DMA
*
* Returned Value:
* None
*
****************************************************************************/
#ifdef CONFIG_SAMV7_SPI_DMADEBUG
static void spi_dma_sampleinit(struct sam_spics_s *spics)
{
/* Put contents of register samples into a known state */
memset(spics->rxdmaregs, 0xff, DMA_NSAMPLES * sizeof(struct sam_dmaregs_s));
memset(spics->txdmaregs, 0xff, DMA_NSAMPLES * sizeof(struct sam_dmaregs_s));
/* Then get the initial samples */
sam_dmasample(spics->rxdma, &spics->rxdmaregs[DMA_INITIAL]);
sam_dmasample(spics->txdma, &spics->txdmaregs[DMA_INITIAL]);
}
#endif
/****************************************************************************
* Name: spi_dma_sampledone
*
* Description:
* Dump sampled DMA registers
*
* Input Parameters:
* spics - Chip select doing the DMA
*
* Returned Value:
* None
*
****************************************************************************/
#ifdef CONFIG_SAMV7_SPI_DMADEBUG
static void spi_dma_sampledone(struct sam_spics_s *spics)
{
/* Sample the final registers */
sam_dmasample(spics->rxdma, &spics->rxdmaregs[DMA_END_TRANSFER]);
sam_dmasample(spics->txdma, &spics->txdmaregs[DMA_END_TRANSFER]);
/* Then dump the sampled DMA registers */
/* Initial register values */
sam_dmadump(spics->txdma, &spics->txdmaregs[DMA_INITIAL],
"TX: Initial Registers");
sam_dmadump(spics->rxdma, &spics->rxdmaregs[DMA_INITIAL],
"RX: Initial Registers");
/* Register values after DMA setup */
sam_dmadump(spics->txdma, &spics->txdmaregs[DMA_AFTER_SETUP],
"TX: After DMA Setup");
sam_dmadump(spics->rxdma, &spics->rxdmaregs[DMA_AFTER_SETUP],
"RX: After DMA Setup");
/* Register values after DMA start */
sam_dmadump(spics->txdma, &spics->txdmaregs[DMA_AFTER_START],
"TX: After DMA Start");
sam_dmadump(spics->rxdma, &spics->rxdmaregs[DMA_AFTER_START],
"RX: After DMA Start");
/* Register values at the time of the TX and RX DMA callbacks
* -OR- DMA timeout.
*
* If the DMA timed out, then there will not be any RX DMA
* callback samples. There is probably no TX DMA callback
* samples either, but we don't know for sure.
*/
sam_dmadump(spics->txdma, &spics->txdmaregs[DMA_CALLBACK],
"TX: At DMA callback");
/* Register values at the end of the DMA */
if (spics->result == -ETIMEDOUT)
{
sam_dmadump(spics->rxdma, &spics->rxdmaregs[DMA_TIMEOUT],
"RX: At DMA timeout");
}
else
{
sam_dmadump(spics->rxdma, &spics->rxdmaregs[DMA_CALLBACK],
"RX: At DMA callback");
}
sam_dmadump(spics->txdma, &spics->txdmaregs[DMA_END_TRANSFER],
"TX: At End-of-Transfer");
sam_dmadump(spics->rxdma, &spics->rxdmaregs[DMA_END_TRANSFER],
"RX: At End-of-Transfer");
}
#endif
/****************************************************************************
* Name: spi_dmatimeout
*
* Description:
* The watchdog timeout setup when a has expired without completion of a
* DMA.
*
* Input Parameters:
* argc - The number of arguments (should be 1)
* arg - The argument (state structure reference cast to uint32_t)
*
* Returned Value:
* None
*
* Assumptions:
* Always called from the interrupt level with interrupts disabled.
*
****************************************************************************/
#ifdef CONFIG_SAMV7_SPI_DMA
static void spi_dmatimeout(int argc, uint32_t arg)
{
struct sam_spics_s *spics = (struct sam_spics_s *)arg;
DEBUGASSERT(spics != NULL);
/* Sample DMA registers at the time of the timeout */
spi_rxdma_sample(spics, DMA_CALLBACK);
/* Report timeout result, perhaps overwriting any failure reports from
* the TX callback.
*/
spics->result = -ETIMEDOUT;
/* Then wake up the waiting thread */
sem_post(&spics->dmawait);
}
#endif
/****************************************************************************
* Name: spi_rxcallback
*
* Description:
* This callback function is invoked at the completion of the SPI RX DMA.
*
* Input Parameters:
* handle - The DMA handler
* arg - A pointer to the chip select structure
* result - The result of the DMA transfer
*
* Returned Value:
* None
*
****************************************************************************/
#ifdef CONFIG_SAMV7_SPI_DMA
static void spi_rxcallback(DMA_HANDLE handle, void *arg, int result)
{
struct sam_spics_s *spics = (struct sam_spics_s *)arg;
DEBUGASSERT(spics != NULL);
/* Cancel the watchdog timeout */
(void)wd_cancel(spics->dmadog);
/* Sample DMA registers at the time of the callback */
spi_rxdma_sample(spics, DMA_CALLBACK);
/* Report the result of the transfer only if the TX callback has not already
* reported an error.
*/
if (spics->result == -EBUSY)
{
/* Save the result of the transfer if no error was previously reported */
spics->result = result;
}
/* Then wake up the waiting thread */
sem_post(&spics->dmawait);
}
#endif
/****************************************************************************
* Name: spi_txcallback
*
* Description:
* This callback function is invoked at the completion of the SPI TX DMA.
*
* Input Parameters:
* handle - The DMA handler
* arg - A pointer to the chip select structure
* result - The result of the DMA transfer
*
* Returned Value:
* None
*
****************************************************************************/
#ifdef CONFIG_SAMV7_SPI_DMA
static void spi_txcallback(DMA_HANDLE handle, void *arg, int result)
{
struct sam_spics_s *spics = (struct sam_spics_s *)arg;
DEBUGASSERT(spics != NULL);
spi_txdma_sample(spics, DMA_CALLBACK);
/* Do nothing on the TX callback unless an error is reported. This
* callback is not really important because the SPI exchange is not
* complete until the RX callback is received.
*/
if (result != OK && spics->result == -EBUSY)
{
/* Save the result of the transfer if an error is reported */
spics->result = result;
}
}
#endif
/****************************************************************************
* Name: spi_regaddr
*
* Description:
* Return the address of an SPI register
*
****************************************************************************/
#ifdef CONFIG_SAMV7_SPI_DMA
static inline uintptr_t spi_regaddr(struct sam_spics_s *spics,
unsigned int offset)
{
struct sam_spidev_s *spi = spi_device(spics);
return spi->base + offset;
}
#endif
/****************************************************************************
* Name: spi_lock
*
* Description:
* On SPI buses where there are multiple devices, it will be necessary to
* lock SPI to have exclusive access to the buses for a sequence of
* transfers. The bus should be locked before the chip is selected. After
* locking the SPI bus, the caller should then also call the setfrequency,
* setbits, and setmode methods to make sure that the SPI is properly
* configured for the device. If the SPI bus is being shared, then it
* may have been left in an incompatible state.
*
* Input Parameters:
* dev - Device-specific state data
* lock - true: Lock spi bus, false: unlock SPI bus
*
* Returned Value:
* None
*
****************************************************************************/
static int spi_lock(struct spi_dev_s *dev, bool lock)
{
struct sam_spics_s *spics = (struct sam_spics_s *)dev;
struct sam_spidev_s *spi = spi_device(spics);
spivdbg("lock=%d\n", lock);
if (lock)
{
/* Take the semaphore (perhaps waiting) */
while (sem_wait(&spi->spisem) != 0)
{
/* The only case that an error should occur here is if the wait was awakened
* by a signal.
*/
ASSERT(errno == EINTR);
}
}
else
{
(void)sem_post(&spi->spisem);
}
return OK;
}
/****************************************************************************
* Name: spi_select
*
* Description:
* This function does not actually set the chip select line. Rather, it
* simply maps the device ID into a chip select number and retains that
* chip select number for later use.
*
* Input Parameters:
* dev - Device-specific state data
* frequency - The SPI frequency requested
*
* Returned Value:
* Returns the actual frequency selected
*
****************************************************************************/
static void spi_select(struct spi_dev_s *dev, enum spi_dev_e devid,
bool selected)
{
struct sam_spics_s *spics = (struct sam_spics_s *)dev;
struct sam_spidev_s *spi = spi_device(spics);
uint32_t regval;
/* Are we selecting or de-selecting the device? */
spivdbg("selected=%d\n", selected);
if (selected)
{
spivdbg("cs=%d\n", spics->cs);
/* Before writing the TDR, the PCS field in the SPI_MR register must be set
* in order to select a slave.
*/
regval = spi_getreg(spi, SAM_SPI_MR_OFFSET);
regval &= ~SPI_MR_PCS_MASK;
regval |= (spi_cs2pcs(spics) << SPI_MR_PCS_SHIFT);
spi_putreg(spi, regval, SAM_SPI_MR_OFFSET);
}
/* Perform any board-specific chip select operations. PIO chip select
* pins may be programmed by the board specific logic in one of two
* different ways. First, the pins may be programmed as SPI peripherals.
* In that case, the pins are completely controlled by the SPI driver.
* The sam_spi[0|1]select methods still needs to be provided, but they
* may be only stubs.
*
* An alternative way to program the PIO chip select pins is as normal
* PIO outputs. In that case, the automatic control of the CS pins is
* bypassed and this function must provide control of the chip select.
* NOTE: In this case, the PIO output pin does *not* have to be the
* same as the NPCS pin normal associated with the chip select number.
*/
spi->select(devid, selected);
}
/****************************************************************************
* Name: spi_setfrequency
*
* Description:
* Set the SPI frequency.
*
* Input Parameters:
* dev - Device-specific state data
* frequency - The SPI frequency requested
*
* Returned Value:
* Returns the actual frequency selected
*
****************************************************************************/
static uint32_t spi_setfrequency(struct spi_dev_s *dev, uint32_t frequency)
{
struct sam_spics_s *spics = (struct sam_spics_s *)dev;
struct sam_spidev_s *spi = spi_device(spics);
uint32_t actual;
uint32_t scbr;
uint32_t dlybs;
uint32_t dlybct;
uint32_t regval;
unsigned int offset;
spivdbg("cs=%d frequency=%d\n", spics->cs, frequency);
/* Check if the requested frequency is the same as the frequency selection */
if (spics->frequency == frequency)
{
/* We are already at this frequency. Return the actual. */
return spics->actual;
}
/* Configure SPI to a frequency as close as possible to the requested frequency.
*
* SPCK frequency = SPI_CLK / SCBR, or SCBR = SPI_CLK / frequency
*/
scbr = SAM_SPI_CLOCK / frequency;
if (scbr < 8)
{
scbr = 8;
}
else if (scbr > 254)
{
scbr = 254;
}
scbr = (scbr + 1) & ~1;
/* Save the new scbr value */
offset = (unsigned int)g_csroffset[spics->cs];
regval = spi_getreg(spi, offset);
regval &= ~(SPI_CSR_SCBR_MASK | SPI_CSR_DLYBS_MASK | SPI_CSR_DLYBCT_MASK);
regval |= scbr << SPI_CSR_SCBR_SHIFT;
/* DLYBS: Delay Before SPCK. This field defines the delay from NPCS valid to the
* first valid SPCK transition. When DLYBS equals zero, the NPCS valid to SPCK
* transition is 1/2 the SPCK clock period. Otherwise, the following equations
* determine the delay:
*
* Delay Before SPCK = DLYBS / SPI_CLK
*
* For a 2uS delay
*
* DLYBS = SPI_CLK * 0.000002 = SPI_CLK / 500000
*/
dlybs = SAM_SPI_CLOCK / 500000;
regval |= dlybs << SPI_CSR_DLYBS_SHIFT;
/* DLYBCT: Delay Between Consecutive Transfers. This field defines the delay
* between two consecutive transfers with the same peripheral without removing
* the chip select. The delay is always inserted after each transfer and
* before removing the chip select if needed.
*
* Delay Between Consecutive Transfers = (32 x DLYBCT) / SPI_CLK
*
* For a 5uS delay:
*
* DLYBCT = SPI_CLK * 0.000005 / 32 = SPI_CLK / 200000 / 32
*/
dlybct = SAM_SPI_CLOCK / 200000 / 32;
regval |= dlybct << SPI_CSR_DLYBCT_SHIFT;
spi_putreg(spi, regval, offset);
/* Calculate the new actual frequency */
actual = SAM_SPI_CLOCK / scbr;
spivdbg("csr[offset=%02x]=%08x actual=%d\n", offset, regval, actual);
/* Save the frequency setting */
spics->frequency = frequency;
spics->actual = actual;
spidbg("Frequency %d->%d\n", frequency, actual);
return actual;
}
/****************************************************************************
* Name: spi_setmode
*
* Description:
* Set the SPI mode. Optional. See enum spi_mode_e for mode definitions
*
* Input Parameters:
* dev - Device-specific state data
* mode - The SPI mode requested
*
* Returned Value:
* none
*
****************************************************************************/
static void spi_setmode(struct spi_dev_s *dev, enum spi_mode_e mode)
{
struct sam_spics_s *spics = (struct sam_spics_s *)dev;
struct sam_spidev_s *spi = spi_device(spics);
uint32_t regval;
unsigned int offset;
spivdbg("cs=%d mode=%d\n", spics->cs, mode);
/* Has the mode changed? */
if (mode != spics->mode)
{
/* Yes... Set the mode appropriately:
*
* SPI CPOL NCPHA
* MODE
* 0 0 1
* 1 0 0
* 2 1 1
* 3 1 0
*/
offset = (unsigned int)g_csroffset[spics->cs];
regval = spi_getreg(spi, offset);
regval &= ~(SPI_CSR_CPOL | SPI_CSR_NCPHA);
switch (mode)
{
case SPIDEV_MODE0: /* CPOL=0; NCPHA=1 */
regval |= SPI_CSR_NCPHA;
break;
case SPIDEV_MODE1: /* CPOL=0; NCPHA=0 */
break;
case SPIDEV_MODE2: /* CPOL=1; NCPHA=1 */
regval |= (SPI_CSR_CPOL | SPI_CSR_NCPHA);
break;
case SPIDEV_MODE3: /* CPOL=1; NCPHA=0 */
regval |= SPI_CSR_CPOL;
break;
default:
DEBUGASSERT(FALSE);
return;
}
spi_putreg(spi, regval, offset);
spivdbg("csr[offset=%02x]=%08x\n", offset, regval);
/* Save the mode so that subsequent re-configurations will be faster */
spics->mode = mode;
}
}
/****************************************************************************
* Name: spi_setbits
*
* Description:
* Set the number if bits per word.
*
* Input Parameters:
* dev - Device-specific state data
* nbits - The number of bits requests
*
* Returned Value:
* none
*
****************************************************************************/
static void spi_setbits(struct spi_dev_s *dev, int nbits)
{
struct sam_spics_s *spics = (struct sam_spics_s *)dev;
struct sam_spidev_s *spi = spi_device(spics);
uint32_t regval;
unsigned int offset;
spivdbg("cs=%d nbits=%d\n", spics->cs, nbits);
DEBUGASSERT(spics && nbits > 7 && nbits < 17);
/* Has the number of bits changed? */
if (nbits != spics->nbits)
{
/* Yes... Set number of bits appropriately */
offset = (unsigned int)g_csroffset[spics->cs];
regval = spi_getreg(spi, offset);
regval &= ~SPI_CSR_BITS_MASK;
regval |= SPI_CSR_BITS(nbits);
spi_putreg(spi, regval, offset);
spivdbg("csr[offset=%02x]=%08x\n", offset, regval);
/* Save the selection so the subsequence re-configurations will be faster */
spics->nbits = nbits;
}
}
/****************************************************************************
* Name: spi_send
*
* Description:
* Exchange one word on SPI
*
* Input Parameters:
* dev - Device-specific state data
* wd - The word to send. the size of the data is determined by the
* number of bits selected for the SPI interface.
*
* Returned Value:
* response
*
****************************************************************************/
static uint16_t spi_send(struct spi_dev_s *dev, uint16_t wd)
{
uint8_t txbyte;
uint8_t rxbyte;
/* spi_exchange can do this. Note: right now, this only deals with 8-bit
* words. If the SPI interface were configured for words of other sizes,
* this would fail.
*/
txbyte = (uint8_t)wd;
rxbyte = (uint8_t)0;
spi_exchange(dev, &txbyte, &rxbyte, 1);
spivdbg("Sent %02x received %02x\n", txbyte, rxbyte);
return (uint16_t)rxbyte;
}
/****************************************************************************
* Name: spi_exchange (and spi_exchange_nodma)
*
* Description:
* Exchange a block of data from SPI. There are two versions of this
* function: (1) One that is enabled only when CONFIG_SAMV7_SPI_DMA=y
* that performs DMA SPI transfers, but only when a larger block of
* data is being transferred. And (2) another version that does polled
* SPI transfers. When CONFIG_SAMV7_SPI_DMA=n the latter is the only
* version avaialable; when CONFIG_SAMV7_SPI_DMA=y, this version is only
* used for short SPI transfers and gets renamed as spi_exchange_nodma).
*
* Input Parameters:
* dev - Device-specific state data
* txbuffer - A pointer to the buffer of data to be sent
* rxbuffer - A pointer to the buffer in which to receive data
* nwords - the length of data that to be exchanged in units of words.
* The wordsize is determined by the number of bits-per-word
* selected for the SPI interface. If nbits <= 8, the data is
* packed into uint8_t's; if nbits >8, the data is packed into
* uint16_t's
*
* Returned Value:
* None
*
****************************************************************************/
#ifdef CONFIG_SAMV7_SPI_DMA
static void spi_exchange_nodma(struct spi_dev_s *dev, const void *txbuffer,
void *rxbuffer, size_t nwords)
#else
static void spi_exchange(struct spi_dev_s *dev, const void *txbuffer,
void *rxbuffer, size_t nwords)
#endif
{
struct sam_spics_s *spics = (struct sam_spics_s *)dev;
struct sam_spidev_s *spi = spi_device(spics);
uint32_t pcs;
uint32_t data;
uint16_t *rxptr16;
uint16_t *txptr16;
uint8_t *rxptr8;
uint8_t *txptr8;
spivdbg("txbuffer=%p rxbuffer=%p nwords=%d\n", txbuffer, rxbuffer, nwords);
/* Set up PCS bits */
pcs = spi_cs2pcs(spics) << SPI_TDR_PCS_SHIFT;
/* Set up working pointers */
if (spics->nbits > 8)
{
rxptr16 = (uint16_t *)rxbuffer;
txptr16 = (uint16_t *)txbuffer;
rxptr8 = NULL;
txptr8 = NULL;
}
else
{
rxptr16 = NULL;
txptr16 = NULL;
rxptr8 = (uint8_t *)rxbuffer;
txptr8 = (uint8_t *)txbuffer;
}
/* Make sure that any previous transfer is flushed from the hardware */
spi_flush(spi);
/* Loop, sending each word in the user-provided data buffer.
*
* Note 1: Good SPI performance would require that we implement DMA
* transfers!
* Note 2: This loop might be made more efficient. Would logic
* like the following improve the throughput? Or would it
* just add the risk of overruns?
*
* Get word 1;
* Send word 1; Now word 1 is "in flight"
* nwords--;
* for ( ; nwords > 0; nwords--)
* {
* Get word N.
* Wait for TDRE meaning that word N-1 has moved to the shift
* register.
* Disable interrupts to keep the following atomic
* Send word N. Now both work N-1 and N are "in flight"
* Wait for RDRF meaning that word N-1 is available
* Read word N-1.
* Re-enable interrupts.
* Save word N-1.
* }
* Wait for RDRF meaning that the final word is available
* Read the final word.
* Save the final word.
*/
for (; nwords > 0; nwords--)
{
/* Get the data to send (0xff if there is no data source). */
if (txptr8)
{
data = (uint32_t)*txptr8++;
}
else if (txptr16)
{
data = (uint32_t)*txptr16++;
}
else
{
data = 0xffff;
}
/* Set the PCS field in the value written to the TDR */
data |= pcs;
/* Do we need to set the LASTXFER bit in the TDR value too? */
#ifdef CONFIG_SPI_VARSELECT
if (nwords == 1)
{
data |= SPI_TDR_LASTXFER;
}
#endif
/* Wait for any previous data written to the TDR to be transferred
* to the serializer.
*/
while ((spi_getreg(spi, SAM_SPI_SR_OFFSET) & SPI_INT_TDRE) == 0);
/* Write the data to transmitted to the Transmit Data Register (TDR) */
spi_putreg(spi, data, SAM_SPI_TDR_OFFSET);
/* Wait for the read data to be available in the RDR.
* TODO: Data transfer rates would be improved using the RX FIFO
* (and also DMA)
*/
while ((spi_getreg(spi, SAM_SPI_SR_OFFSET) & SPI_INT_RDRF) == 0);
/* Read the received data from the SPI Data Register. */
data = spi_getreg(spi, SAM_SPI_RDR_OFFSET);
if (rxptr8)
{
*rxptr8++ = (uint8_t)data;
}
else if (rxptr16)
{
*rxptr16++ = (uint16_t)data;
}
}
}
#ifdef CONFIG_SAMV7_SPI_DMA
static void spi_exchange(struct spi_dev_s *dev, const void *txbuffer,
void *rxbuffer, size_t nwords)
{
struct sam_spics_s *spics = (struct sam_spics_s *)dev;
struct sam_spidev_s *spi = spi_device(spics);
uint32_t rxflags;
uint32_t txflags;
uint32_t txdummy;
uint32_t rxdummy;
uint32_t regaddr;
uint32_t memaddr;
uint32_t width;
size_t nbytes;
int ret;
/* Convert the number of word to a number of bytes */
nbytes = (spics->nbits > 8) ? nwords << 1 : nwords;
/* If we cannot do DMA -OR- if this is a small SPI transfer, then let
* spi_exchange_nodma() do the work.
*/
if (!spics->candma || nbytes <= CONFIG_SAMV7_SPI_DMATHRESHOLD)
{
spi_exchange_nodma(dev, txbuffer, rxbuffer, nwords);
return;
}
spivdbg("txbuffer=%p rxbuffer=%p nwords=%d\n", txbuffer, rxbuffer, nwords);
spics = (struct sam_spics_s *)dev;
spi = spi_device(spics);
DEBUGASSERT(spics && spi);
/* Make sure that any previous transfer is flushed from the hardware */
spi_flush(spi);
/* Sample initial DMA registers */
spi_dma_sampleinit(spics);
/* Select the source and destination width bits */
if (spics->nbits > 8)
{
width = (DMACH_FLAG_PERIPHWIDTH_16BITS | DMACH_FLAG_MEMWIDTH_16BITS);
}
else
{
width = (DMACH_FLAG_PERIPHWIDTH_8BITS | DMACH_FLAG_MEMWIDTH_8BITS);
}
/* Configure the DMA channels. There are four different cases:
*
* 1) A true exchange with the memory address incrementing on both
* RX and TX channels,
* 2) A read operation with the memory address incrementing only on
* the receive channel,
* 3) A write operation where the memory address increments only on
* the receive channel, and
* 4) A corner case where there the memory address does not increment
* on either channel. This case might be used in certain cases
* where you want to assure that certain number of clocks are
* provided on the SPI bus.
*/
/* Configure the RX DMA channel */
rxflags = DMACH_FLAG_FIFOCFG_LARGEST | DMACH_FLAG_PERIPHPID(spi->pid) |
DMACH_FLAG_PERIPHH2SEL | DMACH_FLAG_PERIPHISPERIPH |
DMACH_FLAG_PERIPHCHUNKSIZE_1 | DMACH_FLAG_MEMPID_MAX |
DMACH_FLAG_MEMCHUNKSIZE_1;
/* Set the source and destination width bits */
rxflags |= width;
/* Handle the case where there is no sink buffer */
if (!rxbuffer)
{
/* No sink data buffer. Point to our dummy buffer and leave
* the rxflags so that no address increment is performed.
*/
rxbuffer = (void *)&rxdummy;
}
else
{
/* A receive buffer is available.
*
* Invalidate the RX buffer memory to force re-fetching from RAM when
* the DMA completes
*/
arch_invalidate_dcache((uintptr_t)rxbuffer, (uintptr_t)rxbuffer + nbytes);
/* Use normal RX memory incrementing. */
rxflags |= DMACH_FLAG_MEMINCREMENT;
}
/* Configure the TX DMA channel */
txflags = DMACH_FLAG_FIFOCFG_LARGEST | DMACH_FLAG_PERIPHPID(spi->pid) |
DMACH_FLAG_PERIPHH2SEL | DMACH_FLAG_PERIPHISPERIPH |
DMACH_FLAG_PERIPHCHUNKSIZE_1 | DMACH_FLAG_MEMPID_MAX |
DMACH_FLAG_MEMCHUNKSIZE_1;
/* Set the source and destination width bits */
txflags |= width;
/* Handle the case where there is no source buffer */
if (!txbuffer)
{
/* No source data buffer. Point to our dummy buffer and leave
* the txflags so that no address increment is performed.
*/
txdummy = 0xffffffff;
txbuffer = (const void *)&txdummy;
}
else
{
/* Source data is available. Use normal TX memory incrementing. */
txflags |= DMACH_FLAG_MEMINCREMENT;
}
/* Then configure the DMA channels to make it so */
sam_dmaconfig(spics->rxdma, rxflags);
sam_dmaconfig(spics->txdma, txflags);
/* Configure the RX side of the exchange transfer */
regaddr = spi_regaddr(spics, SAM_SPI_RDR_OFFSET);
memaddr = (uintptr_t)rxbuffer;
ret = sam_dmarxsetup(spics->rxdma, regaddr, memaddr, nwords);
if (ret < 0)
{
dmadbg("ERROR: sam_dmarxsetup failed: %d\n", ret);
return;
}
spi_rxdma_sample(spics, DMA_AFTER_SETUP);
/* Configure the TX side of the exchange transfer */
regaddr = spi_regaddr(spics, SAM_SPI_TDR_OFFSET);
memaddr = (uintptr_t)txbuffer;
ret = sam_dmatxsetup(spics->txdma, regaddr, memaddr, nwords);
if (ret < 0)
{
dmadbg("ERROR: sam_dmatxsetup failed: %d\n", ret);
return;
}
spi_txdma_sample(spics, DMA_AFTER_SETUP);
/* Start the DMA transfer */
spics->result = -EBUSY;
ret = sam_dmastart(spics->rxdma, spi_rxcallback, (void *)spics);
if (ret < 0)
{
dmadbg("ERROR: RX sam_dmastart failed: %d\n", ret);
return;
}
spi_rxdma_sample(spics, DMA_AFTER_START);
ret = sam_dmastart(spics->txdma, spi_txcallback, (void *)spics);
if (ret < 0)
{
dmadbg("ERROR: RX sam_dmastart failed: %d\n", ret);
sam_dmastop(spics->rxdma);
return;
}
spi_txdma_sample(spics, DMA_AFTER_START);
/* Wait for DMA completion. This is done in a loop because there may be
* false alarm semaphore counts that cause sam_wait() not fail to wait
* or to wake-up prematurely (for example due to the receipt of a signal).
* We know that the DMA has completed when the result is anything other
* that -EBUSY.
*/
do
{
/* Start (or re-start) the watchdog timeout */
ret = wd_start(spics->dmadog, DMA_TIMEOUT_TICKS,
(wdentry_t)spi_dmatimeout, 1, (uint32_t)spics);
if (ret != OK)
{
spidbg("ERROR: wd_start failed: %d\n", ret);
}
/* Wait for the DMA complete */
ret = sem_wait(&spics->dmawait);
/* Cancel the watchdog timeout */
(void)wd_cancel(spics->dmadog);
/* Check if we were awakened by an error of some kind */
if (ret < 0)
{
/* EINTR is not a failure. That simply means that the wait
* was awakened by a signal.
*/
int errorcode = errno;
if (errorcode != EINTR)
{
DEBUGPANIC();
return;
}
}
/* Not that we might be awakened before the wait is over due to
* residual counts on the semaphore. So, to handle, that case,
* we loop until something changes the DMA result to any value other
* than -EBUSY.
*/
}
while (spics->result == -EBUSY);
/* Dump the sampled DMA registers */
spi_dma_sampledone(spics);
/* Make sure that the DMA is stopped (it will be stopped automatically
* on normal transfers, but not necessarily when the transfer terminates
* on an error condition).
*/
sam_dmastop(spics->rxdma);
sam_dmastop(spics->txdma);
/* All we can do is complain if the DMA fails */
if (spics->result)
{
spidbg("ERROR: DMA failed with result: %d\n", spics->result);
}
}
#endif /* CONFIG_SAMV7_SPI_DMA */
/****************************************************************************
* Name: spi_sndblock
*
* Description:
* Send a block of data on SPI
*
* Input Parameters:
* dev - Device-specific state data
* buffer - A pointer to the buffer of data to be sent
* nwords - the length of data to send from the buffer in number of words.
* The wordsize is determined by the number of bits-per-word
* selected for the SPI interface. If nbits <= 8, the data is
* packed into uint8_t's; if nbits >8, the data is packed into
* uint16_t's
*
* Returned Value:
* None
*
****************************************************************************/
#ifndef CONFIG_SPI_EXCHANGE
static void spi_sndblock(struct spi_dev_s *dev, const void *buffer,
size_t nwords)
{
/* spi_exchange can do this. */
spi_exchange(dev, buffer, NULL, nwords);
}
#endif
/****************************************************************************
* Name: spi_recvblock
*
* Description:
* Revice a block of data from SPI
*
* Input Parameters:
* dev - Device-specific state data
* buffer - A pointer to the buffer in which to receive data
* nwords - the length of data that can be received in the buffer in number
* of words. The wordsize is determined by the number of bits-per-word
* selected for the SPI interface. If nbits <= 8, the data is
* packed into uint8_t's; if nbits >8, the data is packed into
* uint16_t's
*
* Returned Value:
* None
*
****************************************************************************/
#ifndef CONFIG_SPI_EXCHANGE
static void spi_recvblock(struct spi_dev_s *dev, void *buffer, size_t nwords)
{
/* spi_exchange can do this. */
spi_exchange(dev, NULL, buffer, nwords);
}
#endif
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: sam_spibus_initialize
*
* Description:
* Initialize the selected SPI port in master mode
*
* Input Parameter:
* cs - Chip select number (identifying the "logical" SPI port)
*
* Returned Value:
* Valid SPI device structure reference on success; a NULL on failure
*
****************************************************************************/
FAR struct spi_dev_s *sam_spibus_initialize(int port)
{
FAR struct sam_spidev_s *spi;
FAR struct sam_spics_s *spics;
int csno = (port & __SPI_CS_MASK) >> __SPI_CS_SHIFT;
int spino = (port & __SPI_SPI_MASK) >> __SPI_SPI_SHIFT;
irqstate_t flags;
uint32_t regval;
unsigned int offset;
/* The support SAM parts have only a single SPI port */
spivdbg("port: %d csno: %d spino: %d\n", port, csno, spino);
DEBUGASSERT(csno >= 0 && csno <= SAM_SPI_NCS);
#if defined(CONFIG_SAMV7_SPI0_MASTER) && defined(CONFIG_SAMV7_SPI1_MASTER)
DEBUGASSERT(spino >= 0 && spino <= 1);
#elif defined(CONFIG_SAMV7_SPI0_MASTER)
DEBUGASSERT(spino == 0);
#else
DEBUGASSERT(spino == 1);
#endif
/* Allocate a new state structure for this chip select. NOTE that there
* is no protection if the same chip select is used in two different
* chip select structures.
*/
spics = (struct sam_spics_s *)zalloc(sizeof(struct sam_spics_s));
if (!spics)
{
spidbg("ERROR: Failed to allocate a chip select structure\n");
return NULL;
}
/* Set up the initial state for this chip select structure. Other fields
* were zeroed by zalloc().
*/
#ifdef CONFIG_SAMV7_SPI_DMA
/* Can we do DMA on this peripheral? */
spics->candma = spino ? SAMV7_SPI1_DMA : SAMV7_SPI0_DMA;
/* Pre-allocate DMA channels. */
if (spics->candma)
{
spics->rxdma = sam_dmachannel(0, 0);
if (!spics->rxdma)
{
spidbg("ERROR: Failed to allocate the RX DMA channel\n");
spics->candma = false;
}
}
if (spics->candma)
{
spics->txdma = sam_dmachannel(0, 0);
if (!spics->txdma)
{
spidbg("ERROR: Failed to allocate the TX DMA channel\n");
sam_dmafree(spics->rxdma);
spics->rxdma = NULL;
spics->candma = false;
}
}
#endif
/* Select the SPI operations */
#if defined(CONFIG_SAMV7_SPI0_MASTER) && defined(CONFIG_SAMV7_SPI1_MASTER)
spics->spidev.ops = spino ? &g_spi1ops : &g_spi0ops;
#elif defined(CONFIG_SAMV7_SPI0_MASTER)
spics->spidev.ops = &g_spi0ops;
#else
spics->spidev.ops = &g_spi1ops;
#endif
/* Save the chip select and SPI controller numbers */
spics->cs = csno;
#if defined(CONFIG_SAMV7_SPI0_MASTER) || defined(CONFIG_SAMV7_SPI1_MASTER)
spics->spino = spino;
#endif
/* Get the SPI device structure associated with the chip select */
spi = spi_device(spics);
/* Has the SPI hardware been initialized? */
if (!spi->initialized)
{
/* Enable clocking to the SPI block */
flags = enter_critical_section();
#if defined(CONFIG_SAMV7_SPI0_MASTER) && defined(CONFIG_SAMV7_SPI1_MASTER)
if (spino == 0)
#endif
#if defined(CONFIG_SAMV7_SPI0_MASTER)
{
sam_spi0_enableclk();
/* Configure multiplexed pins as connected on the board. Chip
* select pins must be selected by board-specific logic.
*/
sam_configgpio(GPIO_SPI0_MISO);
sam_configgpio(GPIO_SPI0_MOSI);
sam_configgpio(GPIO_SPI0_SPCK);
}
#endif
#if defined(CONFIG_SAMV7_SPI0_MASTER) && defined(CONFIG_SAMV7_SPI1_MASTER)
else
#endif
#if defined(CONFIG_SAMV7_SPI1_MASTER)
{
sam_spi1_enableclk();
/* Configure multiplexed pins as connected on the board. Chip
* select pins must be selected by board-specific logic.
*/
sam_configgpio(GPIO_SPI1_MISO);
sam_configgpio(GPIO_SPI1_MOSI);
sam_configgpio(GPIO_SPI1_SPCK);
}
#endif
#if defined(CONFIG_SAMV7_SPI_CS_DECODING)
/* Enable Peripheral Chip Select Decoding? */
regval = spi_getreg(spi, SAM_SPI_MR_OFFSET);
regval |= SPI_MR_PCSDEC;
spi_putreg(spi, regval, SAM_SPI_MR_OFFSET);
#endif
/* Disable SPI clocking */
spi_putreg(spi, SPI_CR_SPIDIS, SAM_SPI_CR_OFFSET);
/* Execute a software reset of the SPI (twice) */
spi_putreg(spi, SPI_CR_SWRST, SAM_SPI_CR_OFFSET);
spi_putreg(spi, SPI_CR_SWRST, SAM_SPI_CR_OFFSET);
leave_critical_section(flags);
/* Configure the SPI mode register */
spi_putreg(spi, SPI_MR_MSTR | SPI_MR_MODFDIS, SAM_SPI_MR_OFFSET);
/* And enable the SPI */
spi_putreg(spi, SPI_CR_SPIEN, SAM_SPI_CR_OFFSET);
up_mdelay(20);
/* Flush any pending transfers */
(void)spi_getreg(spi, SAM_SPI_SR_OFFSET);
(void)spi_getreg(spi, SAM_SPI_RDR_OFFSET);
/* Initialize the SPI semaphore that enforces mutually exclusive
* access to the SPI registers.
*/
sem_init(&spi->spisem, 0, 1);
spi->initialized = true;
#ifdef CONFIG_SAMV7_SPI_DMA
/* Initialize the SPI semaphore that is used to wake up the waiting
* thread when the DMA transfer completes.
*/
sem_init(&spics->dmawait, 0, 0);
/* Create a watchdog time to catch DMA timeouts */
spics->dmadog = wd_create();
DEBUGASSERT(spics->dmadog);
#endif
spi_dumpregs(spi, "After initialization");
}
/* Set to mode=0 and nbits=8 and impossible frequency. The SPI will only
* be reconfigured if there is a change.
*/
offset = (unsigned int)g_csroffset[csno];
regval = spi_getreg(spi, offset);
regval &= ~(SPI_CSR_CPOL | SPI_CSR_NCPHA | SPI_CSR_BITS_MASK);
regval |= (SPI_CSR_NCPHA | SPI_CSR_BITS(8));
spi_putreg(spi, regval, offset);
spics->nbits = 8;
spivdbg("csr[offset=%02x]=%08x\n", offset, regval);
return &spics->spidev;
}
#endif /* CONFIG_SAMV7_SPI_MASTER */
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