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SPI DMA design simplification

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git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@2148 42af7a65-404d-4744-a932-0658087f49c3
This commit is contained in:
patacongo 2009-10-17 16:11:55 +00:00
parent 2e8f38671b
commit a2763cf4fc
3 changed files with 88 additions and 283 deletions
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33
arch/arm/src/stm32/stm32_dma.c
View File

@ -301,10 +301,31 @@ void weak_function stm32_dmainitialize(void)
* Name: stm32_dmachannel * Name: stm32_dmachannel
* *
* Description: * Description:
* Allocate a DMA channel * Allocate a DMA channel. This function gives the caller mutually
* exclusive access to the DMA channel specified by the 'chan' argument.
* DMA channels are shared on the STM32: Devices sharing the same DMA
* channel cannot do DMA concurrently! See the DMACHAN_* definitions in
* stm32_dma.h.
*
* If the DMA channel is not available, then stm32_dmachannel() will wait
* until the holder of the channel relinquishes the channel by calling
* stm32_dmafree(). WARNING: If you have two devices sharing a DMA
* channel and the code never releases the channel, the stm32_dmachannel
* call for the other will hang forever in this function! Don't let your
* design do that!
*
* Hmm.. I suppose this interface could be extended to make a non-blocking
* version. Feel free to do that if that is what you need.
* *
* Returned Value: * Returned Value:
* On success, a void* DMA channel handle; NULL on failure * Provided that 'chan' is valid, this function ALWAYS returns a non-NULL,
* void* DMA channel handle. (If 'chan' is invalid, the function will
* assert if debug is enabled or do something ignorant otherwise).
*
* Assumptions:
* - The caller does not hold he DMA channel.
* - The caller can wait for the DMA channel to be freed if it is no
* available.
* *
****************************************************************************/ ****************************************************************************/
@ -326,10 +347,14 @@ DMA_HANDLE stm32_dmachannel(int chan)
} }
/**************************************************************************** /****************************************************************************
* Name: stm32_dmarelease * Name: stm32_dmafree
* *
* Description: * Description:
* Release a DMA channel * Release a DMA channel. If another thread is waiting for this DMA channel
* in a call to stm32_dmachannel, then this function will re-assign the
* DMA channel to that thread and wake it up. NOTE: The 'handle' used
* in this argument must NEVER be used again until stm32_dmachannel() is
* called again to re-gain access to the channel.
* *
* Returned Value: * Returned Value:
* None * None

37
arch/arm/src/stm32/stm32_internal.h
View File

@ -494,24 +494,53 @@ EXTERN void weak_function stm32_dmainitialize(void);
* Name: stm32_dmachannel * Name: stm32_dmachannel
* *
* Description: * Description:
* Allocate a DMA channel * Allocate a DMA channel. This function gives the caller mutually
* exclusive access to the DMA channel specified by the 'chan' argument.
* DMA channels are shared on the STM32: Devices sharing the same DMA
* channel cannot do DMA concurrently! See the DMACHAN_* definitions in
* stm32_dma.h.
*
* If the DMA channel is not available, then stm32_dmachannel() will wait
* until the holder of the channel relinquishes the channel by calling
* stm32_dmafree(). WARNING: If you have two devices sharing a DMA
* channel and the code never releases the channel, the stm32_dmachannel
* call for the other will hang forever in this function! Don't let your
* design do that!
*
* Hmm.. I suppose this interface could be extended to make a non-blocking
* version. Feel free to do that if that is what you need.
* *
* Returned Value: * Returned Value:
* On success, a void* DMA channel handle; NULL on failure * Provided that 'chan' is valid, this function ALWAYS returns a non-NULL,
* void* DMA channel handle. (If 'chan' is invalid, the function will
* assert if debug is enabled or do something ignorant otherwise).
*
* Assumptions:
* - The caller does not hold he DMA channel.
* - The caller can wait for the DMA channel to be freed if it is no
* available.
* *
****************************************************************************/ ****************************************************************************/
EXTERN DMA_HANDLE stm32_dmachannel(int chan); EXTERN DMA_HANDLE stm32_dmachannel(int chan);
/**************************************************************************** /****************************************************************************
* Name: stm32_dmarelease * Name: stm32_dmafree
* *
* Description: * Description:
* Release a DMA channel * Release a DMA channel. If another thread is waiting for this DMA channel
* in a call to stm32_dmachannel, then this function will re-assign the
* DMA channel to that thread and wake it up. NOTE: The 'handle' used
* in this argument must NEVER be used again until stm32_dmachannel() is
* called again to re-gain access to the channel.
* *
* Returned Value: * Returned Value:
* None * None
* *
* Assumptions:
* - The caller holds the DMA channel.
* - There is no DMA in progress
*
****************************************************************************/ ****************************************************************************/
EXTERN void stm32_dmafree(DMA_HANDLE handle); EXTERN void stm32_dmafree(DMA_HANDLE handle);

297
arch/arm/src/stm32/stm32_spi.c
View File

@ -163,14 +163,6 @@ static void spi_dmatxsetup(FAR struct stm32_spidev_s *priv,
FAR const void *txbuffer, FAR const void *txdummy, size_t nwords); FAR const void *txbuffer, FAR const void *txdummy, size_t nwords);
static inline void spi_dmarxstart(FAR struct stm32_spidev_s *priv); static inline void spi_dmarxstart(FAR struct stm32_spidev_s *priv);
static inline void spi_dmatxstart(FAR struct stm32_spidev_s *priv); static inline void spi_dmatxstart(FAR struct stm32_spidev_s *priv);
static inline void spi_dmaexchange(FAR struct stm32_spidev_s *priv,
FAR const void *txbuffer, FAR void *rxbuffer,
size_t nwords);
static inline void spi_dmatxexchange(FAR struct stm32_spidev_s *priv,
FAR const void *txbuffer, FAR void *rxbuffer,
size_t nwords);
static inline void spi_dmarxexchange(FAR struct stm32_spidev_s *priv, FAR const void *txbuffer,
FAR void *rxbuffer, size_t nwords);
#endif #endif
/* SPI methods */ /* SPI methods */
@ -179,11 +171,6 @@ static uint32 spi_setfrequency(FAR struct spi_dev_s *dev, uint32 frequen
static void spi_setmode(FAR struct spi_dev_s *dev, enum spi_mode_e mode); static void spi_setmode(FAR struct spi_dev_s *dev, enum spi_mode_e mode);
static void spi_setbits(FAR struct spi_dev_s *dev, int nbits); static void spi_setbits(FAR struct spi_dev_s *dev, int nbits);
static uint16 spi_send(FAR struct spi_dev_s *dev, uint16 wd); static uint16 spi_send(FAR struct spi_dev_s *dev, uint16 wd);
#ifdef CONFIG_STM32_SPI_DMA
static void spi_copyexchange(FAR struct spi_dev_s *dev,
FAR const void *txbuffer, FAR void *rxbuffer,
size_t nwords);
#endif
static void spi_exchange(FAR struct spi_dev_s *dev, FAR const void *txbuffer, static void spi_exchange(FAR struct spi_dev_s *dev, FAR const void *txbuffer,
FAR void *rxbuffer, size_t nwords); FAR void *rxbuffer, size_t nwords);
#ifndef CONFIG_SPI_EXCHANGE #ifndef CONFIG_SPI_EXCHANGE
@ -652,226 +639,6 @@ static inline void spi_dmatxstart(FAR struct stm32_spidev_s *priv)
} }
#endif #endif
/************************************************************************************
* Name: spi_dmaexchange
*
* Description:
* Perform concurrent RX and TX DMA transfers
*
* priv - Device-specific state data
* txbuffer - A pointer to the buffer of data to be sent
* rxbuffer - A pointer to a buffer in which to receive data
* nwords - the length of data to be exchaned 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_STM32_SPI_DMA
static inline void spi_dmaexchange(FAR struct stm32_spidev_s *priv,
FAR const void *txbuffer, FAR void *rxbuffer,
size_t nwords)
{
uint16 rxdummy = 0xffff;
uint16 txdummy;
/* Setup DMAs */
spi_dmarxsetup(priv, rxbuffer, &rxdummy, nwords);
spi_dmatxsetup(priv, txbuffer, &txdummy, nwords);
/* Start the DMAs */
spi_dmarxstart(priv);
spi_dmatxstart(priv);
/* Then wait for each to complete */
spi_dmarxwait(priv);
spi_dmatxwait(priv);
}
#endif
/************************************************************************************
* Name: spi_dmatxexchange
*
* Description:
* Perform SPI exchange using DMA on the TX side only
*
* priv - Device-specific state data
* txbuffer - A pointer to the buffer of data to be sent
* rxbuffer - A pointer to a buffer in which to receive data
* nwords - the length of data to be exchaned 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_STM32_SPI_DMA
static inline void spi_dmatxexchange(FAR struct stm32_spidev_s *priv,
FAR const void *txbuffer, FAR void *rxbuffer,
size_t nwords)
{
uint16 txdummy;
/* Setup and start the TX DMA */
spi_dmatxsetup(priv, txbuffer, &txdummy, nwords);
spi_dmatxstart(priv);
/* Then read the RX data via a polling loop */
/* 8- or 16-bit mode? */
if (spi_16bitmode(priv))
{
/* 16-bit mode */
uint16 *dest = (uint16*)rxbuffer;
uint16 word;
while (nwords-- > 0)
{
/* Read one word */
word = spi_readword(priv);
/* Is there a buffer to receive the return value? */
if (dest)
{
*dest++ = word;
}
}
}
else
{
/* 8-bit mode */
ubyte *dest = (ubyte*)rxbuffer;
ubyte word;
while (nwords-- > 0)
{
/* Read one word */
word = (ubyte)spi_readword(priv);
/* Is there a buffer to receive the return value? */
if (dest)
{
*dest++ = word;
}
}
}
/* Then wait for the TX DMA to complete (should already be finished) */
spi_dmatxwait(priv);
}
#endif
/************************************************************************************
* Name: spi_dmarxexchange
*
* Description:
* Perform SPI exchange using DMA on the RX side only
*
* priv - Device-specific state data
* txbuffer - A pointer to the buffer of data to be sent
* rxbuffer - A pointer to a buffer in which to receive data
* nwords - the length of data to be exchaned 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_STM32_SPI_DMA
static inline void spi_dmarxexchange(FAR struct stm32_spidev_s *priv,
FAR const void *txbuffer, FAR void *rxbuffer,
size_t nwords)
{
uint16 rxdummy = 0xffff;
/* Setup and start the RX DMA */
spi_dmarxsetup(priv, rxbuffer, &rxdummy, nwords);
spi_dmarxstart(priv);
/* Then send all of the TX data via a copy loop */
/* 8- or 16-bit mode? */
if (spi_16bitmode(priv))
{
/* 16-bit mode */
const uint16 *src = (const uint16*)txbuffer;;
uint16 word;
while (nwords-- > 0)
{
/* Get the next word to write. Is there a source buffer? */
if (src)
{
word = *src++;
}
else
{
word = 0xffff;
}
/* Write one word */
spi_writeword(priv, word);
}
}
else
{
/* 8-bit mode */
const ubyte *src = (const ubyte*)txbuffer;;
ubyte word;
while (nwords-- > 0)
{
/* Get the next word to write. Is there a source buffer? */
if (src)
{
word = *src++;
}
else
{
word = 0xff;
}
/* Write one word */
spi_writeword(priv, (uint16)word);
}
}
/* Then wait for the RX DMA to complete */
spi_dmarxwait(priv);
}
#endif
/************************************************************************************ /************************************************************************************
* Name: spi_modifycr1 * Name: spi_modifycr1
* *
@ -1098,10 +865,10 @@ static uint16 spi_send(FAR struct spi_dev_s *dev, uint16 wd)
} }
/************************************************************************* /*************************************************************************
* Name: spi_exchange (no DMA) or spi_copyexchange (with DMA capability) * Name: spi_exchange (no DMA)
* *
* Description: * Description:
* Exchange a block of data on SPI * Exchange a block of data on SPI without using DMA
* *
* Input Parameters: * Input Parameters:
* dev - Device-specific state data * dev - Device-specific state data
@ -1117,14 +884,9 @@ static uint16 spi_send(FAR struct spi_dev_s *dev, uint16 wd)
* *
************************************************************************************/ ************************************************************************************/
#ifdef CONFIG_STM32_SPI_DMA #ifndef CONFIG_STM32_SPI_DMA
static void spi_copyexchange(FAR struct spi_dev_s *dev,
FAR const void *txbuffer, FAR void *rxbuffer,
size_t nwords)
#else
static void spi_exchange(FAR struct spi_dev_s *dev, FAR const void *txbuffer, static void spi_exchange(FAR struct spi_dev_s *dev, FAR const void *txbuffer,
FAR void *rxbuffer, size_t nwords) FAR void *rxbuffer, size_t nwords)
#endif
{ {
FAR struct stm32_spidev_s *priv = (FAR struct stm32_spidev_s *)dev; FAR struct stm32_spidev_s *priv = (FAR struct stm32_spidev_s *)dev;
DEBUGASSERT(priv && priv->spibase); DEBUGASSERT(priv && priv->spibase);
@ -1198,12 +960,13 @@ static void spi_exchange(FAR struct spi_dev_s *dev, FAR const void *txbuffer,
} }
} }
} }
#endif
/************************************************************************* /*************************************************************************
* Name: spi_exchange (with DMA capability) * Name: spi_exchange (with DMA capability)
* *
* Description: * Description:
* Exchange a block of data on SPI * Exchange a block of data on SPI using DMA
* *
* Input Parameters: * Input Parameters:
* dev - Device-specific state data * dev - Device-specific state data
@ -1224,42 +987,25 @@ static void spi_exchange(FAR struct spi_dev_s *dev, FAR const void *txbuffer,
FAR void *rxbuffer, size_t nwords) FAR void *rxbuffer, size_t nwords)
{ {
FAR struct stm32_spidev_s *priv = (FAR struct stm32_spidev_s *)dev; FAR struct stm32_spidev_s *priv = (FAR struct stm32_spidev_s *)dev;
uint16 rxdummy = 0xffff;
uint16 txdummy;
DEBUGASSERT(priv && priv->spibase); DEBUGASSERT(priv && priv->spibase);
/* Do we have a TX dma channel? */ /* Setup DMAs */
if (priv->txdma) spi_dmarxsetup(priv, rxbuffer, &rxdummy, nwords);
{ spi_dmatxsetup(priv, txbuffer, &txdummy, nwords);
/* Yes.. Do we have an RX dma channel too? */
if (priv->rxdma) /* Start the DMAs */
{
/* Yes.. do the full DMA exchange */
spi_dmaexchange(priv, txbuffer, rxbuffer, nwords); spi_dmarxstart(priv);
} spi_dmatxstart(priv);
else
{
/* No... do the exchange with only TX DMA */
spi_dmatxexchange(priv, txbuffer, rxbuffer, nwords); /* Then wait for each to complete */
}
}
/* Do we have an RX dma channel? */ spi_dmarxwait(priv);
spi_dmatxwait(priv);
else if (priv->rxdma)
{
/* Yes... do the exchange with only RX DMA */
spi_dmarxexchange(priv, txbuffer, rxbuffer, nwords);
}
else
{
/* No... do the exchange with no DMA */
spi_copyexchange(dev, txbuffer, rxbuffer, nwords);
}
} }
#endif #endif
@ -1366,12 +1112,17 @@ static void spi_portinitialize(FAR struct stm32_spidev_s *priv)
sem_init(&priv->rxsem, 0, 0); sem_init(&priv->rxsem, 0, 0);
sem_init(&priv->txsem, 0, 0); sem_init(&priv->txsem, 0, 0);
/* Get DMA channels. Note that if we fail to get a DMA channel, we will just /* Get DMA channels. NOTE: stm32_dmachannel() will always assign the DMA channel.
* fall back to dumb I/O. * if the channel is not available, then stm32_dmachannel() will block and wait
* until the channel becomes available. WARNING: If you have another device sharing
* a DMA channel with SPI and the code never releases that channel, then the call
* to stm32_dmachannel() will hang forever in this function! Don't let your
* design do that!
*/ */
priv->rxdma = stm32_dmachannel(priv->rxch); priv->rxdma = stm32_dmachannel(priv->rxch);
priv->txdma = stm32_dmachannel(priv->txch); priv->txdma = stm32_dmachannel(priv->txch);
DEBUGASSERT(priv->rxdma && priv->txdma);
#endif #endif
/* Enable spi */ /* Enable spi */