/****************************************************************************
* arch/arm/src/lm32/lm32_spi.c
*
* Copyright (C) 2009 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
*
* 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 <semaphore.h>
#include <errno.h>
#include <debug.h>
#include <nuttx/arch.h>
#include <nuttx/spi.h>
#include <arch/irq.h>
#include <arch/board/board.h>
#include "up_internal.h"
#include "up_arch.h"
#include "chip.h"
#include "lm3s_internal.h"
/****************************************************************************
* Definitions
****************************************************************************/
/* How many SSI modules does this chip support? The LM3S6918 supports 2 SSI
* modules (others may support more -- in such case, the following must be
* expanded).
*/
#if LM3S_NSSI == 0
# undef CONFIG_SSI0_DISABLE
# define CONFIG_SSI0_DISABLE 1
# undef CONFIG_SSI1_DISABLE
# define CONFIG_SSI1_DISABLE 1
#elif LM3S_NSSI == 1
# undef CONFIG_SSI1_DISABLE
# define CONFIG_SSI1_DISABLE 1
#endif
/* Which SSI modules have been enabled? */
#ifndef CONFIG_SSI0_DISABLE
# define SSI0_NDX 0 /* Index to SSI0 in g_ssidev[] */
# ifndef CONFIG_SSI1_DISABLE
# define SSI1_NDX 1 /* Index to SSI1 in g_ssidev[] */
# define NSSI_ENABLED 2 /* Two SSI interfaces: SSI0 & SSI1 */
# else
# define NSSI_ENABLED 1 /* One SSI interface: SSI0 */
# define SSI_BASE LM3S_SSI0_BASE
# define SSI_IRQ LM3S_IRQ_SSI0
# endif
#else
# ifndef CONFIG_SSI1_DISABLE
# define SSI1_NDX 0 /* Index to SSI1 in g_ssidev[] */
# define NSSI_ENABLED 1 /* One SSI interface: SSI1 */
# define SSI_BASE LM3S_SSI1_BASE
# define SSI_IRQ LM3S_IRQ_SSI1
# else
# define NSSI_ENABLED 0 /* No SSI interfaces */
# endif
#endif
/* Compile the rest of the file only if at least one SSI interface has been
* enabled.
*/
#if NSSI_ENABLED > 0
/* The number of (16-bit) words that will fit in the Tx FIFO */
#define LM3S_TXFIFO_WORDS 8
/****************************************************************************
* Private Type Definitions
****************************************************************************/
struct lm32_ssidev_s
{
const struct spi_ops_s *ops; /* Common SPI operations */
#ifndef CONFIG_SSI_POLLWAIT
sem_t xfrsem; /* Wait for transfer to complete */
#endif
sem_t exclsem; /* For exclusive access to the SSI bus */
/* These following are the source and destination buffers of the transfer.
* they are retained in this structure so that they will be accessible
* from an interrupt handler. The actual type of the buffer is ubyte is
* nbits <=8 and uint16 is nbits >8.
*/
void *txbuffer; /* Source buffer */
void *rxbuffer; /* Destination buffer */
/* These are functions pointers that are configured to perform the
* appropriate transfer for the particular kind of exchange that is
* occurring. Differnt functions may be selected depending on (1)
* if the tx or txbuffer is NULL and depending on the number of bits
* per word.
*/
void (*txword)(struct lm32_ssidev_s *priv);
void (*rxword)(struct lm32_ssidev_s *priv);
#if NSSI_ENABLED > 1
uint32 base; /* SSI register base address */
#endif
uint32 frequency; /* Current desired SCLK frequency */
uint32 actual; /* Current actual SCLK frequency */
int ntxwords; /* Number of words left to transfer on the Tx FIFO */
int nrxwords; /* Number of words received on the Rx FIFO */
int nwords; /* Number of words to be exchanged */
ubyte mode; /* Current mode */
ubyte nbits; /* Current number of bits per word */
#if !defined(CONFIG_SSI_POLLWAIT) && NSSI_ENABLED > 1
ubyte irq; /* SSI IRQ number */
#endif
};
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
/* SSI register access */
static inline uint32 ssi_getreg(struct lm32_ssidev_s *priv, unsigned int offset);
static inline void ssi_putreg(struct lm32_ssidev_s *priv, unsigned int offset, uint32 value);
/* Misc helpers */
static uint32 ssi_disable(struct lm32_ssidev_s *priv);
static void ssi_enable(struct lm32_ssidev_s *priv, uint32 enable);
static void ssi_semtake(sem_t *sem);
#define ssi_semgive(s) sem_post(s);
/* SSI data transfer */
static void ssi_txnull(struct lm32_ssidev_s *priv);
static void ssi_txuint16(struct lm32_ssidev_s *priv);
static void ssi_txubyte(struct lm32_ssidev_s *priv);
static void ssi_rxnull(struct lm32_ssidev_s *priv);
static void ssi_rxuint16(struct lm32_ssidev_s *priv);
static void ssi_rxubyte(struct lm32_ssidev_s *priv);
static inline boolean ssi_txfifofull(struct lm32_ssidev_s *priv);
static inline boolean ssi_rxfifonotempty(struct lm32_ssidev_s *priv);
static int ssi_performtx(struct lm32_ssidev_s *priv);
static inline void ssi_performrx(struct lm32_ssidev_s *priv);
static int ssi_transfer(struct lm32_ssidev_s *priv, const void *txbuffer,
void *rxbuffer, unsigned int nwords);
/* Interrupt handling */
#ifndef CONFIG_SSI_POLLWAIT
static inline struct lm32_ssidev_s *ssi_mapirq(int irq);
static int ssi_interrupt(int irq, void *context);
#endif
/* SPI methods */
static void ssi_setfrequencyinternal(struct lm32_ssidev_s *priv, uint32 frequency);
static uint32 ssi_setfrequency(FAR struct spi_dev_s *dev, uint32 frequency);
static void ssi_setmodeinternal(struct lm32_ssidev_s *priv, enum spi_mode_e mode);
static void ssi_setmode(FAR struct spi_dev_s *dev, enum spi_mode_e mode);
static void ssi_setbitsinternal(struct lm32_ssidev_s *priv, int nbits);
static void ssi_setbits(FAR struct spi_dev_s *dev, int nbits);
static uint16 ssi_send(FAR struct spi_dev_s *dev, uint16 wd);
#ifdef CONFIG_SPI_EXCHANGE
static void ssi_exchange(FAR struct spi_dev_s *dev, FAR const void *txbuffer,
FAR void *rxbuffer, size_t nwords);
#else
static void ssi_sndblock(FAR struct spi_dev_s *dev, FAR const void *buffer, size_t nwords);
static void ssi_recvblock(FAR struct spi_dev_s *dev, FAR void *buffer, size_t nwords);
#endif
/****************************************************************************
* Private Data
****************************************************************************/
/* Common SSI operations */
static const struct spi_ops_s g_spiops =
{
.select = lm3s_spiselect, /* Provided externally by board logic */
.setfrequency = ssi_setfrequency,
.setmode = ssi_setmode,
.setbits = ssi_setbits,
.status = lm3s_spistatus, /* Provided externally by board logic */
.send = ssi_send,
#ifdef CONFIG_SPI_EXCHANGE
.exchange = ssi_exchange,
#else
.sndblock = ssi_sndblock,
.recvblock = ssi_recvblock,
#endif
};
/* This supports is up to two SSI busses/ports */
static struct lm32_ssidev_s g_ssidev[] =
{
#ifndef CONFIG_SSI0_DISABLE
{
.ops = &g_spiops,
#if NSSI_ENABLED > 1
.base = IMX_CSSI0_VBASE,
#endif
#if !defined(CONFIG_SSI_POLLWAIT) && NSSI_ENABLED > 1
.irq = IMX_IRQ_CSSI0,
#endif
},
#endif
#ifndef CONFIG_SSI1_DISABLE
{
.ops = &g_spiops,
#if NSSI_ENABLED > 1
.base = IMX_CSSI1_VBASE,
#endif
#if !defined(CONFIG_SSI_POLLWAIT) && NSSI_ENABLED > 1
.irq = IMX_IRQ_CSSI1,
#endif
},
#endif
};
/****************************************************************************
* Public Data
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: ssi_getreg
*
* Description:
* Read the SSI register at this offeset
*
* Input Parameters:
* priv - Device-specific state data
* offset - Offset to the SSI register from the register base address
*
* Returned Value:
* Value of the register at this offset
*
****************************************************************************/
static inline uint32 ssi_getreg(struct lm32_ssidev_s *priv, unsigned int offset)
{
#if NSSI_ENABLED > 1
return getreg32(priv->base + offset);
#else
return getreg32(SSI_BASE + offset);
#endif
}
/****************************************************************************
* Name: ssi_putreg
*
* Description:
* Write the value to the SSI register at this offeset
*
* Input Parameters:
* priv - Device-specific state data
* offset - Offset to the SSI register from the register base address
* value - Value to write
*
* Returned Value:
* None
*
****************************************************************************/
static inline void ssi_putreg(struct lm32_ssidev_s *priv, unsigned int offset, uint32 value)
{
#if NSSI_ENABLED > 1
putreg32(value, priv->base + offset);
#else
putreg32(value, SSI_BASE + offset);
#endif
}
/****************************************************************************
* Name: ssi_disable
*
* Description:
* Disable SSI operation. NOTE: The SSI must be disabled before any control
* registers can be re-programmed.
*
* Input Parameters:
* priv - Device-specific state data
*
* Returned Value:
* State of the SSI before the SSE was disabled
*
****************************************************************************/
static uint32 ssi_disable(struct lm32_ssidev_s *priv)
{
uint32 retval;
uint32 regval;
retval = ssi_getreg(priv, LM3S_SSI_CR1_OFFSET);
regval = (retval & ~SSI_CR1_SSE);
ssi_putreg(priv, LM3S_SSI_CR1_OFFSET, regval);
return retval;
}
/****************************************************************************
* Name: ssi_enable
*
* Description:
* Restore the SSI operational state
*
* Input Parameters:
* priv - Device-specific state data
* enable - The previous operational state
*
* Returned Value:
*
****************************************************************************/
static void ssi_enable(struct lm32_ssidev_s *priv, uint32 enable)
{
uint32 regval = ssi_getreg(priv, LM3S_SSI_CR1_OFFSET);
regval &= ~SSI_CR1_SSE;
regval |= (enable & SSI_CR1_SSE);
ssi_putreg(priv, LM3S_SSI_CR1_OFFSET, regval);
}
/****************************************************************************
* Name: ssi_semtake
*
* Description:
* Wait for a semaphore (handling interruption by signals);
*
* Input Parameters:
* priv - Device-specific state data
* enable - The previous operational state
*
* Returned Value:
*
****************************************************************************/
static void ssi_semtake(sem_t *sem)
{
int ret;
do
{
ret = sem_wait(sem);
}
while (ret < 0 && errno == EINTR);
DEBUGASSERT(ret == 0);
}
/****************************************************************************
* Name: ssi_txnull, ssi_txuint16, and ssi_txubyte
*
* Description:
* Transfer all ones, a ubyte, or uint16 to Tx FIFO and update the txbuffer
* pointer appropriately. The selected function dependes on (1) if there
* is a source txbuffer provided, and (2) if the number of bits per
* word is <=8 or >8.
*
* Input Parameters:
* priv - Device-specific state data
*
* Returned Value:
* None
*
****************************************************************************/
static void ssi_txnull(struct lm32_ssidev_s *priv)
{
ssi_putreg(priv, LM3S_SSI_DR_OFFSET, 0xffff);
}
static void ssi_txuint16(struct lm32_ssidev_s *priv)
{
uint16 *ptr = (uint16*)priv->txbuffer;
ssi_putreg(priv, LM3S_SSI_DR_OFFSET, (uint32)(*ptr++));
priv->txbuffer = (void*)ptr;
}
static void ssi_txubyte(struct lm32_ssidev_s *priv)
{
ubyte *ptr = (ubyte*)priv->txbuffer;
ssi_putreg(priv, LM3S_SSI_DR_OFFSET, (uint32)(*ptr++));
priv->txbuffer = (void*)ptr;
}
/****************************************************************************
* Name: ssi_rxnull, ssi_rxuint16, and ssi_rxubyte
*
* Description:
* Discard input, save a ubyte, or or save a uint16 from Tx FIFO in the
* user rxvbuffer and update the rxbuffer pointer appropriately. The
* selected function dependes on (1) if there is a desination rxbuffer
* provided, and (2) if the number of bits per word is <=8 or >8.
*
* Input Parameters:
* priv - Device-specific state data
*
* Returned Value:
* None
*
****************************************************************************/
static void ssi_rxnull(struct lm32_ssidev_s *priv)
{
(void)ssi_getreg(priv, LM3S_SSI_DR_OFFSET);
}
static void ssi_rxuint16(struct lm32_ssidev_s *priv)
{
uint16 *ptr = (uint16*)priv->rxbuffer;
*ptr++ = (uint16)ssi_getreg(priv, LM3S_SSI_DR_OFFSET);
priv->rxbuffer = (void*)ptr;
}
static void ssi_rxubyte(struct lm32_ssidev_s *priv)
{
ubyte *ptr = (ubyte*)priv->rxbuffer;
*ptr++ = (ubyte)ssi_getreg(priv, LM3S_SSI_DR_OFFSET);
priv->rxbuffer = (void*)ptr;
}
/****************************************************************************
* Name: ssi_txfifofull
*
* Description:
* Return TRUE if the Tx FIFO is not full
*
* Input Parameters:
* priv - Device-specific state data
*
* Returned Value:
* TRUE: Not full
*
****************************************************************************/
static inline boolean ssi_txfifofull(struct lm32_ssidev_s *priv)
{
return (ssi_getreg(priv, LM3S_SSI_SR_OFFSET) & SSI_SR_TNF) != 0;
}
/****************************************************************************
* Name: ssi_rxfifonotempty
*
* Description:
* Return TRUE if the Rx FIFO is not empty
*
* Input Parameters:
* priv - Device-specific state data
*
* Returned Value:
* TRUE: Not empty
*
****************************************************************************/
static inline boolean ssi_rxfifonotempty(struct lm32_ssidev_s *priv)
{
return (ssi_getreg(priv, LM3S_SSI_SR_OFFSET) & SSI_SR_RNE) != 0;
}
/****************************************************************************
* Name: ssi_performtx
*
* Description:
* If the Tx FIFO is empty, then transfer as many words as we can to
* the FIFO.
*
* Input Parameters:
* priv - Device-specific state data
*
* Returned Value:
* The number of words written to the Tx FIFO (a value from 0 to 8,
* inclusive).
*
****************************************************************************/
static int ssi_performtx(struct lm32_ssidev_s *priv)
{
uint32 regval;
int ntxd = 0; /* Number of words written to Tx FIFO */
/* Check if the Tx FIFO is full */
if (!ssi_txfifofull(priv))
{
/* Not full.. Check if all of the Tx words have been sent */
if (priv->ntxwords > 0)
{
/* No.. Transfer more words until either the Tx FIFO is full or
* until all of the user provided data has been sent.
*/
for (; ntxd < priv->ntxwords && !ssi_txfifofull(priv); ntxd++)
{
priv->txword(priv);
}
/* Update the count of words to to transferred */
priv->ntxwords -= ntxd;
}
/* Check again... Now have all of the Tx words been sent? */
#ifndef CONFIG_SSI_POLLWAIT
regval = ssi_getreg(priv, LM3S_SSI_IM_OFFSET);
if (priv->ntxwords > 0)
{
/* No.. Enable the Tx FIFO interrupt. This interrupt occurs
* when the Tx FIFO is 1/2 full or less.
*/
#ifdef CONFIG_DEBUG
regval |= (SSI_IM_TX|SSI_RIS_ROR)
#else
regval |= SSI_IM_TX;
#endif
}
else
{
/* Yes.. Disable the Tx FIFO interrupt. The final stages of
* the transfer will be driven by Rx FIFO interrupts.
*/
regval &= ~(SSI_IM_TX|SSI_RIS_ROR);
}
ssi_putreg(priv, LM3S_SSI_IM_OFFSET, regval);
#endif /* CONFIG_SSI_POLLWAIT */
}
return ntxd;
}
/****************************************************************************
* Name: ssi_performrx
*
* Description:
* Transfer as many bytes as possible from the Rx FIFO to the user Rx
* buffer (if one was provided).
*
* Input Parameters:
* priv - Device-specific state data
*
* Returned Value:
* None
*
****************************************************************************/
static inline void ssi_performrx(struct lm32_ssidev_s *priv)
{
#ifndef CONFIG_SSI_POLLWAIT
uint32 regval;
#endif
/* Loop while data is available in the Rx FIFO */
while (ssi_rxfifonotempty(priv))
{
/* Have all of the requested words been transferred from the Rx FIFO? */
if (priv->nrxwords < priv->nwords)
{
/* No.. Read more data from Rx FIFO */
priv->rxword(priv);
priv->nrxwords++;
}
}
/* The Rx FIFO is now empty. While there is Tx data to be sent, the
* transfer will be driven by Tx FIFO interrupts. The final part
* of the transfer is driven by Rx FIFO interrupts only.
*/
#ifndef CONFIG_SSI_POLLWAIT
regval = ssi_getreg(priv, LM3S_SSI_IM_OFFSET);
if (priv->ntxwords == 0 && priv->nrxwords < priv->nwords)
{
/* There are no more outgoing words to send, but there are
* additional incoming words expected (I would think that this
* a real corner case, be we will handle it with an extra
* interrupt, probably an Rx timeout).
*/
#ifdef CONFIG_DEBUG
regval |= (SSI_IM_RX|SSI_IM_RT|SSI_IM_ROR);
#else
regval |= (SSI_IM_RX|SSI_IM_RT);
#endif
}
else
{
/* No.. there are either more Tx words to send or all Rx words
* have received. Disable Rx FIFO interrupts.
*/
regval &= ~(SSI_IM_RX|SSI_IM_RT);
}
ssi_putreg(priv, LM3S_SSI_IM_OFFSET, regval);
#endif /* CONFIG_SSI_POLLWAIT */
}
/****************************************************************************
* Name: ssi_transfer
*
* Description:
* Exchange a block data with the SPI device
*
* Input Parameters:
* priv - Device-specific state data
* txbuffer - The buffer of data to send to the device (may be NULL).
* rxbuffer - The buffer to receive data from the device (may be NULL).
* nwords - The total number of words to be exchanged. If the interface
* uses <= 8 bits per word, then this is the number of ubytes;
* if the interface uses >8 bits per word, then this is the
* number of uint16's
*
* Returned Value:
* 0: success, <0:Negated error number on failure
*
****************************************************************************/
static int ssi_transfer(struct lm32_ssidev_s *priv, const void *txbuffer,
void *rxbuffer, unsigned int nwords)
{
#ifndef CONFIG_SSI_POLLWAIT
irqstate_t flags;
#endif
int ntxd;
ssi_semtake(&priv->exclsem);
/* Set up to perform the transfer */
priv->txbuffer = (ubyte*)txbuffer; /* Source buffer */
priv->rxbuffer = (ubyte*)rxbuffer; /* Destination buffer */
priv->ntxwords = nwords; /* Number of words left to send */
priv->nrxwords = 0; /* Number of words received */
priv->nwords = nwords; /* Total number of exchanges */
/* Set up the low-level data transfer function pointers */
if (priv->nbits > 8)
{
priv->txword = ssi_txuint16;
priv->rxword = ssi_rxuint16;
}
else
{
priv->txword = ssi_txubyte;
priv->rxword = ssi_rxubyte;
}
if (!txbuffer)
{
priv->txword = ssi_txnull;
}
if (!rxbuffer)
{
priv->rxword = ssi_rxnull;
}
/* Prime the Tx FIFO to start the sequence (saves one interrupt).
* At this point, all SSI interrupts should be disabled, but the
* operation of ssi_performtx() will set up the interrupts
* approapriately.
*/
#ifndef CONFIG_SSI_POLLWAIT
flags = irqsave();
ntxd = ssi_performtx(priv);
/* Wait for the transfer to complete. Since there is no handshake
* with SPI, the following should complete even if there are problems
* with the transfer, so it should be safe with no timeout.
*/
irqrestore(flags);
do
{
ssi_semtake(&priv->xfrsem);
}
while (priv->nrxwords < priv->nwords);
#else
/* Perform the transfer using polling logic. This will totally
* dominate the CPU until the transfer is complete. Only recommended
* if (1) your SPI is very fast, and (2) if you only use very short
* transfers.
*/
do
{
/* Handle outgoing Tx FIFO transfers */
ntxd = ssi_performtx(priv);
/* Handle incoming Rx FIFO transfers */
ssi_performrx(priv);
/* If there are other threads at this same priority level,
* the following may help:
*/
sched_yield();
}
while (priv->nrxwords < priv->nwords);
#endif
ssi_semgive(&priv->exclsem);
return OK;
}
/****************************************************************************
* Name: ssi_mapirq
*
* Description:
* Map an IRQ number into the appropriate SSI device
*
* Input Parameters:
* irq - The IRQ number to be mapped
*
* Returned Value:
* On success, a reference to the private data structgure for this IRQ.
* NULL on failrue.
*
****************************************************************************/
#ifndef CONFIG_SSI_POLLWAIT
static inline struct lm32_ssidev_s *ssi_mapirq(int irq)
{
switch (irq)
{
#ifndef CONFIG_SSI0_DISABLE
case LM3S_IRQ_SSI0:
return &g_ssidev[SSI0_NDX];
#endif
#ifndef CONFIG_SSI1_DISABLE
case LM3S_IRQ_SSI1:
return &g_ssidev[SSI1_NDX];
#endif
default:
return NULL;
}
}
#endif
/****************************************************************************
* Name: ssi_interrupt
*
* Description:
* Exchange a block data with the SSI device
*
* Input Parameters:
* priv - Device-specific state data
* txbuffer - The buffer of data to send to the device (may be NULL).
* rxbuffer - The buffer to receive data from the device (may be NULL).
* nwords - The total number of words to be exchanged. If the interface
* uses <= 8 bits per word, then this is the number of ubytes;
* if the interface uses >8 bits per word, then this is the
* number of uint16's
*
* Returned Value:
* 0: success, <0:Negated error number on failure
*
****************************************************************************/
#ifndef CONFIG_SSI_POLLWAIT
static int ssi_interrupt(int irq, void *context)
{
struct lm32_ssidev_s *priv = ssi_mapirq(irq);
uint32 regval;
int ntxd;
DEBUGASSERT(priv != NULL);
/* Clear pending interrupts */
regval = ssi_getreg(priv, LM3S_SSI_RIS_OFFSET);
ssi_putreg(priv, LM3S_SSI_ICR_OFFSET, regval);
/* Check for Rx FIFO overruns */
#ifdef CONFIG_DEBUG
if ((regval & SSI_RIS_ROR) != 0)
{
lldbg("Rx FIFO Overrun!\n");
}
#endif
/* Handle outgoing Tx FIFO transfers */
ntxd = ssi_performtx(priv);
/* Handle incoming Rx FIFO transfers */
ssi_performrx(priv);
/* Check if the transfer is complete */
if (priv->nrxwords >= priv->nwords)
{
/* Yes.. Disable all SSI interrupt sources */
ssi_putreg(priv, LM3S_SSI_IM_OFFSET, 0);
/* Wake up the waiting thread */
ssi_semgive(&priv->xfrsem);
}
return OK;
}
#endif
/****************************************************************************
* Name: ssi_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 void ssi_setfrequencyinternal(struct lm32_ssidev_s *priv, uint32 frequency)
{
uint32 maxdvsr;
uint32 cpsdvsr;
uint32 regval;
uint32 scr;
if (priv && frequency != priv->frequency)
{
/* "The serial bit rate is derived by dividing down the input clock
* (FSysClk). The clock is first divided by an even prescale value
* CPSDVSR from 2 to 254, which is programmed in the SSI Clock Prescale
* (SSI_CPSR) register ... The clock is further divided by a value
* from 1 to 256, which is 1 + SCR, where SCR is the value programmed
* i n the SSI Control0 (SSICR0) register ...
*
* "The frequency of the output clock SSIClk is defined by:
*
* "SSIClk = FSysClk / (CPSDVSR * (1 + SCR))
*
* "Note: Although the SSIClk transmit clock can theoretically be 25 MHz,
* the module may not be able to operate at that speed. For master mode,
* the system clock must be at least two times faster than the SSIClk.
* For slave mode, the system clock must be at least 12 times faster
* than the SSIClk."
*/
if (frequency > SYSCLK_FREQUENCY/2)
{
frequency = SYSCLK_FREQUENCY/2;
}
/* Find optimal values for CPSDVSR and SCR. This loop is inefficient,
* but should not have to execute many times.
*
* EXAMPLE 1: SYSCLK_FREQUENCY=50,000,0000 and frequency=400,000.
*
* maxcvsr = 125
* 1. cpsdvsr = 2, scr = 61 -> DONE
*
* This would correspond to an actual frequency of:
* 50,000,000 / (2 * (62)) = 403,226
*
* EXAMPLE 2: SYSCLK_FREQUENCY=50,000,0000 and frequency=25,000,000.
*
* maxcvsr = 2
* 1. cpsdvsr = 2, scr = 0 -> DONE
*
* This would correspond to an actual frequency of:
* 50,000,000 / (2 * (1)) = 25,000,000
*/
maxdvsr = SYSCLK_FREQUENCY / frequency;
cpsdvsr = 0;
do
{
cpsdvsr += 2;
scr = (maxdvsr / cpsdvsr) - 1;
}
while (scr > 255);
/* Set CPDVSR */
DEBUGASSERT(cpdvsr < 255);
ssi_putreg(priv, LM3S_SSI_CPSR_OFFSET, cpsdvsr);
/* Set SCR */
regval = ssi_getreg(priv, LM3S_SSI_CR0_OFFSET);
regval &= ~SSI_CR0_SCR_MASK;
regval |= (scr << SSI_CR0_SCR_SHIFT);
ssi_putreg(priv, LM3S_SSI_CR0_OFFSET, regval);
/* Calcluate the actual frequency */
priv->actual = SYSCLK_FREQUENCY / (cpsdvsr * (scr + 1));
}
}
static uint32 ssi_setfrequency(FAR struct spi_dev_s *dev, uint32 frequency)
{
struct lm32_ssidev_s *priv = (struct lm32_ssidev_s *)dev;
uint32 enable;
/* NOTE that the SSI must be disabled when setting any configuration registers. */
ssi_semtake(&priv->exclsem);
enable = ssi_disable(priv);
ssi_setfrequencyinternal(priv, frequency);
ssi_enable(priv, enable);
ssi_semgive(&priv->exclsem);
return priv->actual;
}
/****************************************************************************
* Name: ssi_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 ssi_setmodeinternal(struct lm32_ssidev_s *priv, enum spi_mode_e mode)
{
uint32 modebits;
uint32 regval;
ssi_semtake(&priv->exclsem);
if (priv && mode != priv->mode)
{
/* Select the CTL register bits based on the selected mode */
switch (mode)
{
case SPIDEV_MODE0: /* CPOL=0 CHPHA=0 */
modebits = 0;
break;
case SPIDEV_MODE1: /* CPOL=0 CHPHA=1 */
modebits = SSI_CR0_SPH;
break;
case SPIDEV_MODE2: /* CPOL=1 CHPHA=0 */
modebits = SSI_CR0_SPO;
break;
case SPIDEV_MODE3: /* CPOL=1 CHPHA=1 */
modebits = SSI_CR0_SPH|SSI_CR0_SPO;
break;
default:
return;
}
/* Then set the selected mode */
regval = ssi_getreg(priv, LM3S_SSI_CR0_OFFSET);
regval &= ~SSI_CR0_FRF_MASK;
regval |= modebits;
ssi_putreg(priv, LM3S_SSI_CR0_OFFSET, regval);
}
}
static void ssi_setmode(FAR struct spi_dev_s *dev, enum spi_mode_e mode)
{
struct lm32_ssidev_s *priv = (struct lm32_ssidev_s *)dev;
uint32 enable;
/* NOTE that the SSI must be disabled when setting any configuration registers. */
ssi_semtake(&priv->exclsem);
enable = ssi_disable(priv);
ssi_setmodeinternal(priv, mode);
ssi_enable(priv, enable);
ssi_semgive(&priv->exclsem);
}
/****************************************************************************
* Name: ssi_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 ssi_setbitsinternal(struct lm32_ssidev_s *priv, int nbits)
{
uint32 regval;
ssi_semtake(&priv->exclsem);
if (priv && nbits != priv->nbits && nbits >=4 && nbits <= 16)
{
regval = ssi_getreg(priv, LM3S_SSI_CR0_OFFSET);
regval &= ~SSI_CR0_DSS_MASK;
regval |= ((nbits - 1) << SSI_CR0_DSS_SHIFT);
ssi_putreg(priv, LM3S_SSI_CR0_OFFSET, regval);
priv->nbits = nbits;
}
}
static void ssi_setbits(FAR struct spi_dev_s *dev, int nbits)
{
struct lm32_ssidev_s *priv = (struct lm32_ssidev_s *)dev;
uint32 enable;
/* NOTE that the SSI must be disabled when setting any configuration registers. */
ssi_semtake(&priv->exclsem);
enable = ssi_disable(priv);
ssi_setbitsinternal(priv, nbits);
ssi_enable(priv, enable);
ssi_semgive(&priv->exclsem);
}
/****************************************************************************
* Name: ssi_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 ssi_send(FAR struct spi_dev_s *dev, uint16 wd)
{
struct lm32_ssidev_s *priv = (struct lm32_ssidev_s*)dev;
uint16 response = 0;
(void)ssi_transfer(priv, &wd, &response, 1);
return response;
}
/****************************************************************************
* Name: SPI_EXCHANGE
*
* Description:
* Exahange a block of data from SPI. Required.
*
* Input Parameters:
* dev - Device-specific state data
* buffer - A pointer to the buffer of data to be sent
* rxbuffer - A pointer to the buffer in which to recieve 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 ubytes; if nbits >8, the data is packed into uint16's
*
* Returned Value:
* None
*
****************************************************************************/
#ifdef CONFIG_SPI_EXCHANGE
static void ssi_exchange(FAR struct spi_dev_s *dev, FAR const void *txbuffer,
FAR void *rxbuffer, size_t nwords)
{
struct lm32_ssidev_s *priv = (struct lm32_ssidev_s *)dev;
(void)ssi_transfer(priv, txbuffer, rxbuffer, nwords);
}
#endif
/*************************************************************************
* Name: ssi_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 ubytes; if nbits >8, the data is packed into uint16's
*
* Returned Value:
* None
*
****************************************************************************/
#ifndef CONFIG_SPI_EXCHANGE
static void ssi_sndblock(FAR struct spi_dev_s *dev, FAR const void *buffer, size_t nwords)
{
struct lm32_ssidev_s *priv = (struct lm32_ssidev_s *)dev;
(void)ssi_transfer(priv, buffer, NULL, nwords);
}
#endif
/****************************************************************************
* Name: ssi_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 recieve 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 ubytes; if nbits >8, the data is packed into uint16's
*
* Returned Value:
* None
*
****************************************************************************/
#ifndef CONFIG_SPI_EXCHANGE
static void ssi_recvblock(FAR struct spi_dev_s *dev, FAR void *buffer, size_t nwords)
{
struct lm32_ssidev_s *priv = (struct lm32_ssidev_s *)dev;
(void)ssi_transfer(priv, NULL, buffer, nwords);
}
#endif
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: up_spiinitialize
*
* Description:
* Initialize common parts the selected SPI port. Initialization of
* chip select GPIOs must have been performed by board specific logic
* prior to calling this function. Specifically: GPIOs should have
* been configured for output, and all chip selects disabled.
*
* One GPIO, SS (PB2 on the eZ8F091) is reserved as a chip select. However,
* If multiple devices on on the bus, then multiple chip selects will be
* required. Theregore, all GPIO chip management is deferred to board-
* specific logic.
*
* Input Parameter:
* Port number (for hardware that has mutiple SSI interfaces)
*
* Returned Value:
* Valid SPI device structure reference on succcess; a NULL on failure
*
****************************************************************************/
FAR struct spi_dev_s *up_spiinitialize(int port)
{
struct lm32_ssidev_s *priv;
irqstate_t flags;
ubyte regval;
/* Set up for the selected port */
flags = irqsave();
switch (port)
{
#ifndef CONFIG_SSI0_DISABLE
case 0:
/* Select SSI0 */
priv = &g_ssidev[SSI0_NDX];
/* Enable the SSI0 peripheral */
regval = getreg32(LM3S_SYSCON_RCGC1);
regval |= SYSCON_RCGC1_SSI0;
putreg32(regval, LM3S_SYSCON_RCGC1);
/* Configure SSI0 GPIOs (NOTE that SS is not initialized here, the
* logic in this file makes no assumptions about chip select)
*/
lm3s_configgpio(GPIO_SSI0_CLK); /* PA2: SSI0 clock (SSI0Clk) */
/* lm3s_configgpio(GPIO_SSI0_FSS); PA3: SSI0 frame (SSI0Fss) */
lm3s_configgpio(GPIO_SSI0_RX); /* PA4: SSI0 receive (SSI0Rx) */
lm3s_configgpio(GPIO_SSI0_TX); /* PA5: SSI0 transmit (SSI0Tx) */
break;
#endif /* CONFIG_SSI0_DISABLE */
#ifndef CONFIG_SSI1_DISABLE
case 1:
/* Select SSI0 */
priv = &g_ssidev[SSI1_NDX];
/* Enable the SSI1 peripheral */
regval = getreg32(LM3S_SYSCON_RCGC1);
regval |= SYSCON_RCGC1_SSI1;
putreg32(regval, LM3S_SYSCON_RCGC1);
/* Configure SSI1 GPIOs */
lm3s_configgpio(GPIO_SSI1_CLK); /* PE0: SSI1 clock (SSI1Clk) */
/* lm3s_configgpio(GPIO_SSI1_FSS); PE1: SSI1 frame (SSI1Fss) */
lm3s_configgpio(GPIO_SSI1_RX); /* PE2: SSI1 receive (SSI1Rx) */
lm3s_configgpio(GPIO_SSI1_TX); /* PE3: SSI1 transmit (SSI1Tx) */
break;
#endif /* CONFIG_SSI1_DISABLE */
default:
irqrestore(flags);
return NULL;
}
/* Initialize the state structure */
#ifndef CONFIG_SSI_POLLWAIT
sem_init(&priv->xfrsem, 0, 0);
#endif
sem_init(&priv->exclsem, 0, 1);
/* Set all CR1 fields to reset state. This will be master mode. */
ssi_putreg(priv, LM3S_SSI_CR1_OFFSET, 0);
/* Set all CR0 fields to the reset state. This will also select Freescale SPI mode. */
ssi_putreg(priv, LM3S_SSI_CR0_OFFSET, 0);
/* Set the initial mode to mode 0 */
ssi_setmodeinternal(priv, SPIDEV_MODE0);
/* Set the initial data width to 8-bits */
ssi_setbitsinternal(priv, 8);
/* Set the initialize clock frequency for detection */
ssi_setfrequencyinternal(priv, 400000);
/* Disable all SSI interrupt sources */
ssi_putreg(priv, LM3S_SSI_IM_OFFSET, 0);
/* Attach the interrupt */
#ifndef CONFIG_SSI_POLLWAIT
#if NSSI_ENABLED > 1
irq_attach(priv->irq, (xcpt_t)ssi_interrupt);
#else
irq_attach(SSI_IRQ, (xcpt_t)ssi_interrupt);
#endif
#endif /* CONFIG_SSI_POLLWAIT */
/* Enable the SSI for operation */
ssi_enable(priv, SSI_CR1_SSE);
/* Enable SSI interrupts (They are still disabled at the source). */
#ifndef CONFIG_SSI_POLLWAIT
#if NSSI_ENABLED > 1
up_enable_irq(priv->irq);
#else
up_enable_irq(SSI_IRQ);
#endif
#endif /* CONFIG_SSI_POLLWAIT */
irqrestore(flags);
return (FAR struct spi_dev_s *)priv;
}
#endif /* NSSI_ENABLED > 0 */
