/*!
* @brief Initiate (start) a transfer using DMA. This is not a public API as it is called from
* other driver functions
*/
static dspi_status_t DSPI_DRV_DmaMasterStartTransfer(uint32_t instance,
const dspi_dma_device_t * device,
const uint8_t * sendBuffer,
uint8_t * receiveBuffer,
size_t transferByteCount)
{
/* instantiate local variable of type dspi_dma_master_state_t and point to global state */
dspi_dma_master_state_t * dspiDmaState = (dspi_dma_master_state_t *)g_dspiStatePtr[instance];
/* For temporarily storing DMA instance and channel */
uint8_t transferSizeInBytes = 1U;
uint32_t calculatedBaudRate;
dspi_command_config_t command; /* create an instance of the data command struct*/
SPI_Type *base = g_dspiBase[instance];
uint32_t txTransferByteCnt = 0;
uint32_t rxTransferByteCnt = 0;
/* Initialize s_wordToSend */
s_wordToSend = 0;
/* Check that we're not busy.*/
if (dspiDmaState->isTransferInProgress)
{
return kStatus_DSPI_Busy;
}
/* Calculate the transfer size on bits/frame */
if (dspiDmaState->bitsPerFrame <= 8)
{
transferSizeInBytes = 1U;
}
else if (dspiDmaState->bitsPerFrame <= 16)
{
transferSizeInBytes = 2U;
}
else
{
transferSizeInBytes = 4U;
}
/* Configure bus for this device. If NULL is passed, we assume the caller has
* preconfigured the bus using DSPI_DRV_DmaMasterConfigureBus().
* Do nothing for calculatedBaudRate. If the user wants to know the calculatedBaudRate
* then they can call this function separately.
*/
if (device)
{
DSPI_DRV_DmaMasterConfigureBus(instance, device, &calculatedBaudRate);
dspiDmaState->bitsPerFrame = device->dataBusConfig.bitsPerFrame; /*update bits/frame*/
}
/* Check the transfer byte count. If bits/frame > 8, meaning 2 bytes, and if
* the transfer byte count is an odd count we'll have to increase the TX transfer byte count
* by one and assert a flag to indicate to the send functions that it will
* need to handle an extra byte.
* For receive, we actually round down the transfer count to the next lowest even number.
* Then in the interrupt handler, we take care of geting this last byte.
*/
if ((dspiDmaState->bitsPerFrame > 8) && (transferByteCount & 1UL))
{
dspiDmaState->extraByte = true;
txTransferByteCnt = transferByteCount + 1U; /* Increment to next even byte count */
rxTransferByteCnt = transferByteCount & ~1U; /* Decrement to next even byte count */
}
else
{
dspiDmaState->extraByte = false;
txTransferByteCnt = transferByteCount;
rxTransferByteCnt = transferByteCount;
}
/* Store the receiveBuffer pointer and receive byte count to the run-time state struct
* for later use in the interrupt handler.
*/
dspiDmaState->rxBuffer = (uint8_t *)receiveBuffer;
dspiDmaState->rxTransferByteCnt = rxTransferByteCnt;
/* Save information about the transfer for use by the ISR.*/
dspiDmaState->isTransferInProgress = true;
/* Reset the transfer counter to 0. Normally this is done via the PUSHR[CTCNT], but as we
* are under DMA controller, we won't be able to change this bit dynamically after the
* first word is transferred.
*/
DSPI_HAL_PresetTransferCount(base, 0);
/* flush the fifos*/
DSPI_HAL_SetFlushFifoCmd(base, true, true);
/* Clear status flags that may have been set from previous transfers */
DSPI_HAL_ClearStatusFlag(base, kDspiTxComplete);
DSPI_HAL_ClearStatusFlag(base, kDspiEndOfQueue);
DSPI_HAL_ClearStatusFlag(base, kDspiTxFifoUnderflow);
DSPI_HAL_ClearStatusFlag(base, kDspiTxFifoFillRequest);
DSPI_HAL_ClearStatusFlag(base, kDspiRxFifoOverflow);
DSPI_HAL_ClearStatusFlag(base, kDspiRxFifoDrainRequest);
/************************************************************************************
* Set up the RX DMA channel Transfer Control Descriptor (TCD)
* Do this before filling the TX FIFO.
* Note, if there is no remaining receive count, then bypass RX DMA set up.
* This means we only have one byte to read of a 16-bit data word and will read this
* in the complete transfer function.
***********************************************************************************/
/* If a receive buffer is used and if rxTransferByteCnt > 0 */
if (rxTransferByteCnt)
{
if (!receiveBuffer)
{
/* Set up this channel's control which includes enabling the DMA interrupt */
DMA_DRV_ConfigTransfer(&dspiDmaState->dmaRxChannel,
kDmaPeripheralToPeripheral,
transferSizeInBytes,
DSPI_HAL_GetPoprRegAddr(base), /* src is data register */
(uint32_t)(&s_rxBuffIfNull), /* dest is temporary location */
(uint32_t)(rxTransferByteCnt));
}
else
{
/* Set up this channel's control which includes enabling the DMA interrupt */
DMA_DRV_ConfigTransfer(&dspiDmaState->dmaRxChannel,
kDmaPeripheralToMemory,
transferSizeInBytes,
DSPI_HAL_GetPoprRegAddr(base), /* src is data register */
(uint32_t)(receiveBuffer), /* dest is rx buffer */
(uint32_t)(rxTransferByteCnt));
/* Destination size is only 1 byte */
DMA_DRV_SetDestTransferSize(&dspiDmaState->dmaRxChannel, 1U);
}
/* Enable the DMA peripheral request */
DMA_DRV_StartChannel(&dspiDmaState->dmaRxChannel);
}
else if (dspiDmaState->extraByte)
{
/* Need to receive only one frame - extra byte by calling Rx callback function*/
DSPI_DRV_DmaRxCallback((void *)instance, kDmaIdle);
}
/************************************************************************************
* Set up the Last Command/data Word Intermediate Buffer and fill up the TX FIFO.
***********************************************************************************/
/* Before sending the data, we first need to initialize the data command struct
* Configure the data command attributes for the desired PCS, CTAR, and continuous PCS
* which are derived from the run-time state struct
*/
command.whichPcs = dspiDmaState->whichPcs;
command.whichCtar = dspiDmaState->whichCtar;
command.clearTransferCount = false; /* don't clear the transfer count */
/************************************************************************
* Next, set up the Last Command/data Word Intermediate Buffer before
* filling up the TX FIFO
* Create a 32-bit word with the final 16-bit command settings. This means
* that EOQ = 1 and CONT = 0.
* This 32-bit word will also be initialized with the final data byte/word
* from the send source buffer and then the entire 32-bit word will be
* transferred to the DSPI PUSHR.
************************************************************************/
/* Declare a variable for storing the last send data (either 8- or 16-bit) */
uint32_t lastWord = 0;
/* If a send buffer was provided, the word comes from there. Otherwise we just send
* a zero (initialized above).
*/
if (sendBuffer)
{
/* Store the last byte from the send buffer */
if (dspiDmaState->bitsPerFrame <= 8)
{
lastWord = sendBuffer[txTransferByteCnt-1]; /* Last byte */
}
/* Store the last two bytes the send buffer */
else
{
/* If 16-bit transfers and odd transfer byte count then an extra byte was added
* to the transfer byte count, but we cannot access more of the send buffer
*/
if(!dspiDmaState->extraByte)
{
lastWord = sendBuffer[txTransferByteCnt-1] ; /* Save off the last byte */
lastWord = lastWord << 8U; /* Shift to MSB (separate step due to MISHA) */
}
lastWord |= sendBuffer[txTransferByteCnt-2]; /* OR with next to last byte */
}
}
/* Now, build the last command/data word intermediate buffer */
command.isChipSelectContinuous = false; /* Always clear CONT for last data word */
command.isEndOfQueue = true; /* Set EOQ for last data word */
s_lastCmdData = DSPI_HAL_GetFormattedCommand(base, &command) | lastWord;
/************************************************************************
* Begin TX DMA channels transfer control descriptor set up.
* 1. First, set up intermediate buffers which contain 16-bit commands.
* 2. Set up the DMA Software Transfer Control Descriptors (STCD) for various
* scenarios:
* - Channel for intermediate buffer to TX FIFO
* - Channel for source buffer to intermediate buffer
* - STCD for scatter/gather for end of previous channel to replace
* intermediate buffer with last-command buffer.
************************************************************************/
/************************************************************************
* Intermediate Buffer
* Create a 32-bit word with the 16-bit command settings. Data from
* the send source buffer will be transferred here and then the entire
* 32-bit word will be transferred to the DSPI PUSHR.
* This buffer will be preloaded with the next data word in the send buffer
************************************************************************/
/* restore the isChipSelectContinuous setting to the original value as it was cleared above */
command.isChipSelectContinuous = dspiDmaState->isChipSelectContinuous;
command.isEndOfQueue = false; /* Clear End of Queue (previously set for last cmd/data word)*/
s_cmdData = DSPI_HAL_GetFormattedCommand(base, &command);
/* Place the next data from the send buffer into the intermediate buffer (preload it)
* based on whether it is one byte or two.
*/
if (dspiDmaState->bitsPerFrame <= 8)
{
/* If a send buffer was provided, the word comes from there. Otherwise we just send
* a zero (initialized above).
*/
if (sendBuffer)
{
s_wordToSend = *sendBuffer; /* queue up the next data */
++sendBuffer; /* increment to next data word*/
}
--txTransferByteCnt; /* decrement txTransferByteCnt*/
}
else
{
/* If a send buffer was provided, the word comes from there. Otherwise we just send
* a zero (initialized above).
*/
if (sendBuffer)
{
s_wordToSend = *sendBuffer;
++sendBuffer; /* increment to next data byte */
/* Note, if the extraByte flag is set and we're down to the last two bytes we can still
* do this even though we're going past the sendBuffer size. We're just reading data we
* don't care about anyways since it is dummy data to make up for the last byte.
*/
s_wordToSend |= (unsigned)(*sendBuffer) << 8U;
++sendBuffer; /* increment to next data byte */
}
txTransferByteCnt -= 2; /* decrement txTransferByteCnt by 2 bytes */
}
s_cmdData |= s_wordToSend; /* write s_wordToSend to intermediate buffer */
/* For Tx, DSPI need two DMA channel, one for calculate the command and data into one value
* (dmaTxCmdChannel), and another for push the value into DSPI PUSHR register (dmaTxDataChannel).
* The dmaTxCmdChannel DMA channel will be triggered by DSPI Tx FIFO, and the dmaTxDataChannel
* DMA channel will be linked to calculate DMA channel and triggered by this channel also.
*/
/* If the transfer size is less than size of one frame, only transmit the last byte that calculated */
if (!txTransferByteCnt)
{
DMA_DRV_ConfigTransfer(&dspiDmaState->dmaTxDataChannel, kDmaMemoryToPeripheral,
4u, (uint32_t)(&s_lastCmdData),
DSPI_HAL_GetMasterPushrRegAddr(base), 4u);
/* Register callback for last byte transmitting */
DMA_DRV_RegisterCallback(&dspiDmaState->dmaTxDataChannel, DSPI_DRV_DmaTxLastCallback, (void *)instance);
}
else
{
/* Config DMA to copy data from generated cmd data to FIFO */
if (dspiDmaState->bitsPerFrame <= 8)
{
DMA_DRV_ConfigTransfer(&dspiDmaState->dmaTxDataChannel, kDmaPeripheralToPeripheral,
4u, (uint32_t)(&s_cmdData),
DSPI_HAL_GetMasterPushrRegAddr(base),
(uint32_t)((txTransferByteCnt) * 4));
}
else
{
DMA_DRV_ConfigTransfer(&dspiDmaState->dmaTxDataChannel, kDmaPeripheralToPeripheral,
4u, (uint32_t)(&s_cmdData),
DSPI_HAL_GetMasterPushrRegAddr(base),
(uint32_t)((txTransferByteCnt) * 2));
}
/* Register Tx callback function */
DMA_DRV_RegisterCallback(&dspiDmaState->dmaTxDataChannel, DSPI_DRV_DmaTxCallback, (void *)instance);
/* Config dmaTxCmdChannel channel if send buffer is provided */
if (sendBuffer)
{
dma_channel_link_config_t config;
DMA_DRV_ConfigTransfer(&dspiDmaState->dmaTxCmdChannel, kDmaMemoryToPeripheral,
1u, (uint32_t)(sendBuffer),
(uint32_t)(&s_cmdData),
(uint32_t)(txTransferByteCnt - transferSizeInBytes));
if (dspiDmaState->bitsPerFrame > 8)
{
DMA_DRV_SetDestTransferSize(&dspiDmaState->dmaTxCmdChannel, 2U);
}
/* Link dmaTxCmdChannel after dmaTxDataChannel */
config.channel1 = dspiDmaState->dmaTxCmdChannel.channel;
config.channel2 = 0;
config.linkType = kDmaChannelLinkChan1;
DMA_DRV_ConfigChanLink(&dspiDmaState->dmaTxDataChannel, &config);
/* start channel */
DMA_DRV_StartChannel(&dspiDmaState->dmaTxCmdChannel);
}
}
/* Register callback */
DMA_DRV_RegisterCallback(&dspiDmaState->dmaRxChannel, DSPI_DRV_DmaRxCallback, (void *)instance);
/* Enable the Receive FIFO Drain DMA Request */
DSPI_HAL_SetRxFifoDrainDmaIntMode(base, kDspiGenerateDmaReq, true);
/* Enable TFFF DMA request */
DSPI_HAL_SetTxFifoFillDmaIntMode(base, kDspiGenerateDmaReq, true);
/* Enable the DMA peripheral request */
DMA_DRV_StartChannel(&dspiDmaState->dmaTxDataChannel);
return kStatus_DSPI_Success;
}
/*!
* @brief Fill up the TX FIFO with data.
* This function fills up the TX FIFO with initial data for start of transfers where it will
* first clear the transfer count. Otherwise, if the TX FIFO fill is part of an ongoing transfer
* then do not clear the transfer count. The param "isInitialData" is used to determine if this
* is an initial data fill.
* This is not a public API as it is called from other driver functions.
*/
static void DSPI_DRV_MasterFillupTxFifo(uint32_t instance)
{
/* instantiate local variable of type dspi_master_state_t and point to global state */
dspi_master_state_t * dspiState = (dspi_master_state_t *)g_dspiStatePtr[instance];
SPI_Type *base = g_dspiBase[instance];
dspi_command_config_t command; /* create an instance of the data command struct*/
uint32_t cmd; /* Command word to be OR'd with data word */
uint16_t wordToSend = 0;
/* Declare variables for storing volatile data later in the code */
uint32_t remainingReceiveByteCount, remainingSendByteCount;
/* Before sending the data, we first need to initialize the data command struct
* Configure the data command attributes for the desired PCS, CTAR, and continuous PCS
* which are derived from the run-time state struct
*/
command.whichPcs = dspiState->whichPcs;
command.whichCtar = dspiState->whichCtar;
command.isChipSelectContinuous = dspiState->isChipSelectContinuous;
command.isEndOfQueue = 0;
command.clearTransferCount = 0;
/* "Build" the command word. Only do this once since the commad word members don't
* change until the last word sent (which is when the end of queue flag gets set).
*/
cmd = DSPI_HAL_GetFormattedCommand(base, &command);
/* Store the DSPI state struct volatile member variables into temporary
* non-volatile variables to allow for MISRA compliant calculations
*/
remainingSendByteCount = dspiState->remainingSendByteCount;
remainingReceiveByteCount = dspiState->remainingReceiveByteCount;
/* Architectural note: When developing the TX FIFO fill functionality, it was found that to
* achieve more efficient run-time performance, it was better to first check the bits/frame
* setting and then proceed with the FIFO fill management process, rather than to clutter the
* FIFO fill process with continual checks of the bits/frame setting.
*/
/* If bits/frame is greater than one byte */
if (dspiState->bitsPerFrame > 8)
{
/* Fill the fifo until it is full or until the send word count is 0 or until the difference
* between the remainingReceiveByteCount and remainingSendByteCount equals the FIFO depth.
* The reason for checking the difference is to ensure we only send as much as the
* RX FIFO can receive.
* For this case where bitsPerFrame > 8, each entry in the FIFO contains 2 bytes of the
* send data, hence the difference between the remainingReceiveByteCount and
* remainingSendByteCount must be divided by 2 to convert this difference into a
* 16-bit (2 byte) value.
*/
while((DSPI_HAL_GetStatusFlag(base, kDspiTxFifoFillRequest) == 1) &&
((remainingReceiveByteCount - remainingSendByteCount)/2 <
g_dspiFifoSize[instance]))
{
/* On the last word to be sent, set the end of queue flag in the data command struct
* and ensure that the CONT bit in the PUSHR is also cleared even if it was cleared to
* begin with. If CONT is set it means continuous chip select operation and to ensure
* the chip select is de-asserted, this bit must be cleared on the last data word.
*/
if (dspiState->remainingSendByteCount == 2)
{
command.isEndOfQueue = 1;
command.isChipSelectContinuous = 0;
cmd = DSPI_HAL_GetFormattedCommand(base, &command);
/* If there is an extra byte to send due to an odd byte count, prepare the final
* wordToSend here
*/
if (dspiState->sendBuffer)
{
if (dspiState->extraByte)
{
wordToSend = *(dspiState->sendBuffer);
}
else
{
wordToSend = *(dspiState->sendBuffer);
++dspiState->sendBuffer; /* increment to next data byte */
wordToSend |= (unsigned)(*(dspiState->sendBuffer)) << 8U;
}
}
}
/* For all words except the last word */
else
{
/* If a send buffer was provided, the word comes from there. Otherwise we just send
* a zero (initialized above).
*/
if (dspiState->sendBuffer)
{
wordToSend = *(dspiState->sendBuffer);
++dspiState->sendBuffer; /* increment to next data byte */
wordToSend |= (unsigned)(*(dspiState->sendBuffer)) << 8U;
++dspiState->sendBuffer; /* increment to next data byte */
}
}
DSPI_HAL_WriteCmdDataMastermode(base, cmd|wordToSend);
/* Try to clear the TFFF; if the TX FIFO is full this will clear */
DSPI_HAL_ClearStatusFlag(base, kDspiTxFifoFillRequest);
dspiState->remainingSendByteCount -= 2; /* decrement remainingSendByteCount by 2 */
/* exit loop if send count is zero, else update local variables for next loop */
if (dspiState->remainingSendByteCount == 0)
{
break;
}
else
{
/* Store the DSPI state struct volatile member variables into temporary
* non-volatile variables to allow for MISRA compliant calculations
*/
remainingSendByteCount = dspiState->remainingSendByteCount;
}
} /* End of TX FIFO fill while loop */
}
/* Optimized for bits/frame less than or equal to one byte. */
else
{
/* Fill the fifo until it is full or until the send word count is 0 or until the difference
* between the remainingReceiveByteCount and remainingSendByteCount equals the FIFO depth.
* The reason for checking the difference is to ensure we only send as much as the
* RX FIFO can receive.
*/
while((DSPI_HAL_GetStatusFlag(base, kDspiTxFifoFillRequest) == 1) &&
((remainingReceiveByteCount - remainingSendByteCount) <
g_dspiFifoSize[instance]))
{
/* On the last word to be sent, set the end of queue flag in the data command struct
* and ensure that the CONT bit in the PUSHR is also cleared even if it was cleared to
* begin with. If CONT is set it means continuous chip select operation and to ensure
* the chip select is de-asserted, this bit must be cleared on the last data word.
*/
if (dspiState->remainingSendByteCount == 1)
{
command.isEndOfQueue = 1;
command.isChipSelectContinuous = 0;
cmd = DSPI_HAL_GetFormattedCommand(base, &command);
}
/* If a send buffer was provided, the word comes from there. Otherwise we just send
* a zero (initialized above).
*/
if (dspiState->sendBuffer)
{
wordToSend = *(dspiState->sendBuffer);
++dspiState->sendBuffer; /* increment to next data word*/
}
DSPI_HAL_WriteCmdDataMastermode(base, cmd|wordToSend);
/* Try to clear the TFFF; if the TX FIFO is full this will clear */
DSPI_HAL_ClearStatusFlag(base, kDspiTxFifoFillRequest);
--dspiState->remainingSendByteCount; /* decrement remainingSendByteCount*/
/* exit loop if send count is zero, else update local variables for next loop */
if (dspiState->remainingSendByteCount == 0)
{
break;
}
else
{
/* Store the DSPI state struct volatile member variables into temporary
* non-volatile variables to allow for MISRA compliant calculations
*/
remainingSendByteCount = dspiState->remainingSendByteCount;
}
} /* End of TX FIFO fill while loop */
}
}
