drivers/spi/spi_mcux_lpspi.c

/*
 * Copyright (c) 2018, NXP
 *
 * SPDX-License-Identifier: Apache-2.0
 */

#define DT_DRV_COMPAT nxp_imx_lpspi

#include <errno.h>
#include <drivers/spi.h>
#include <drivers/clock_control.h>
#include <fsl_lpspi.h>
#include <logging/log.h>
#ifdef CONFIG_SPI_MCUX_LPSPI_DMA
#include <drivers/dma.h>
#endif

LOG_MODULE_REGISTER(spi_mcux_lpspi, CONFIG_SPI_LOG_LEVEL);

#include "spi_context.h"

#define CHIP_SELECT_COUNT	4
#define MAX_DATA_WIDTH		4096

struct spi_mcux_config {
	LPSPI_Type *base;
	const struct device *clock_dev;
	clock_control_subsys_t clock_subsys;
	void (*irq_config_func)(const struct device *dev);
	uint32_t pcs_sck_delay;
	uint32_t sck_pcs_delay;
	uint32_t transfer_delay;
};

#ifdef CONFIG_SPI_MCUX_LPSPI_DMA
#define SPI_MCUX_LPSPI_DMA_ERROR_FLAG	0x01
#define SPI_MCUX_LPSPI_DMA_RX_DONE_FLAG	0x02
#define SPI_MCUX_LPSPI_DMA_TX_DONE_FLAG	0x04
#define SPI_MCUX_LPSPI_DMA_DONE_FLAG		\
	(SPI_MCUX_LPSPI_DMA_RX_DONE_FLAG | SPI_MCUX_LPSPI_DMA_TX_DONE_FLAG)

struct stream {
	const struct device *dma_dev;
	uint32_t channel; /* stores the channel for dma */
	struct dma_config dma_cfg;
	struct dma_block_config dma_blk_cfg;
};
#endif

struct spi_mcux_data {
	const struct device *dev;
	lpspi_master_handle_t handle;
	struct spi_context ctx;
	size_t transfer_len;
#ifdef CONFIG_SPI_MCUX_LPSPI_DMA
	volatile uint32_t status_flags;
	struct stream dma_rx;
	struct stream dma_tx;
	/* dummy value used for transferring NOP when tx buf is null */
	uint32_t dummy_tx_buffer;
	/* dummy value used to read RX data into when rx buf is null */
	uint32_t dummy_rx_buffer;
#endif
};

static void spi_mcux_transfer_next_packet(const struct device *dev)
{
	const struct spi_mcux_config *config = dev->config;
	struct spi_mcux_data *data = dev->data;
	LPSPI_Type *base = config->base;
	struct spi_context *ctx = &data->ctx;
	lpspi_transfer_t transfer;
	status_t status;

	if ((ctx->tx_len == 0) && (ctx->rx_len == 0)) {
		/* nothing left to rx or tx, we're done! */
		spi_context_cs_control(&data->ctx, false);
		spi_context_complete(&data->ctx, 0);
		return;
	}

	transfer.configFlags = kLPSPI_MasterPcsContinuous |
			       (ctx->config->slave << LPSPI_MASTER_PCS_SHIFT);

	if (ctx->tx_len == 0) {
		/* rx only, nothing to tx */
		transfer.txData = NULL;
		transfer.rxData = ctx->rx_buf;
		transfer.dataSize = ctx->rx_len;
	} else if (ctx->rx_len == 0) {
		/* tx only, nothing to rx */
		transfer.txData = (uint8_t *) ctx->tx_buf;
		transfer.rxData = NULL;
		transfer.dataSize = ctx->tx_len;
	} else if (ctx->tx_len == ctx->rx_len) {
		/* rx and tx are the same length */
		transfer.txData = (uint8_t *) ctx->tx_buf;
		transfer.rxData = ctx->rx_buf;
		transfer.dataSize = ctx->tx_len;
	} else if (ctx->tx_len > ctx->rx_len) {
		/* Break up the tx into multiple transfers so we don't have to
		 * rx into a longer intermediate buffer. Leave chip select
		 * active between transfers.
		 */
		transfer.txData = (uint8_t *) ctx->tx_buf;
		transfer.rxData = ctx->rx_buf;
		transfer.dataSize = ctx->rx_len;
		transfer.configFlags |= kLPSPI_MasterPcsContinuous;
	} else {
		/* Break up the rx into multiple transfers so we don't have to
		 * tx from a longer intermediate buffer. Leave chip select
		 * active between transfers.
		 */
		transfer.txData = (uint8_t *) ctx->tx_buf;
		transfer.rxData = ctx->rx_buf;
		transfer.dataSize = ctx->tx_len;
		transfer.configFlags |= kLPSPI_MasterPcsContinuous;
	}

	if (!(ctx->tx_count <= 1 && ctx->rx_count <= 1)) {
		transfer.configFlags |= kLPSPI_MasterPcsContinuous;
	}

	data->transfer_len = transfer.dataSize;

	status = LPSPI_MasterTransferNonBlocking(base, &data->handle,
						 &transfer);
	if (status != kStatus_Success) {
		LOG_ERR("Transfer could not start");
	}
}

static void spi_mcux_isr(const struct device *dev)
{
	const struct spi_mcux_config *config = dev->config;
	struct spi_mcux_data *data = dev->data;
	LPSPI_Type *base = config->base;

	LPSPI_MasterTransferHandleIRQ(base, &data->handle);
}

static void spi_mcux_master_transfer_callback(LPSPI_Type *base,
		lpspi_master_handle_t *handle, status_t status, void *userData)
{
	struct spi_mcux_data *data = userData;

	spi_context_update_tx(&data->ctx, 1, data->transfer_len);
	spi_context_update_rx(&data->ctx, 1, data->transfer_len);

	spi_mcux_transfer_next_packet(data->dev);
}

static int spi_mcux_configure(const struct device *dev,
			      const struct spi_config *spi_cfg)
{
	const struct spi_mcux_config *config = dev->config;
	struct spi_mcux_data *data = dev->data;
	LPSPI_Type *base = config->base;
	lpspi_master_config_t master_config;
	uint32_t clock_freq;
	uint32_t word_size;

	if (spi_context_configured(&data->ctx, spi_cfg)) {
		/* This configuration is already in use */
		return 0;
	}

	if (spi_cfg->operation & SPI_HALF_DUPLEX) {
		LOG_ERR("Half-duplex not supported");
		return -ENOTSUP;
	}

	LPSPI_MasterGetDefaultConfig(&master_config);

	if (spi_cfg->slave > CHIP_SELECT_COUNT) {
		LOG_ERR("Slave %d is greater than %d",
			    spi_cfg->slave,
			    CHIP_SELECT_COUNT);
		return -EINVAL;
	}

	word_size = SPI_WORD_SIZE_GET(spi_cfg->operation);
	if (word_size > MAX_DATA_WIDTH) {
		LOG_ERR("Word size %d is greater than %d",
			    word_size, MAX_DATA_WIDTH);
		return -EINVAL;
	}

	master_config.bitsPerFrame = word_size;

	master_config.cpol =
		(SPI_MODE_GET(spi_cfg->operation) & SPI_MODE_CPOL)
		? kLPSPI_ClockPolarityActiveLow
		: kLPSPI_ClockPolarityActiveHigh;

	master_config.cpha =
		(SPI_MODE_GET(spi_cfg->operation) & SPI_MODE_CPHA)
		? kLPSPI_ClockPhaseSecondEdge
		: kLPSPI_ClockPhaseFirstEdge;

	master_config.direction =
		(spi_cfg->operation & SPI_TRANSFER_LSB)
		? kLPSPI_LsbFirst
		: kLPSPI_MsbFirst;

	master_config.baudRate = spi_cfg->frequency;

	master_config.pcsToSckDelayInNanoSec = config->pcs_sck_delay;
	master_config.lastSckToPcsDelayInNanoSec = config->sck_pcs_delay;
	master_config.betweenTransferDelayInNanoSec = config->transfer_delay;

	if (clock_control_get_rate(config->clock_dev, config->clock_subsys,
				   &clock_freq)) {
		return -EINVAL;
	}

	LPSPI_MasterInit(base, &master_config, clock_freq);

	LPSPI_MasterTransferCreateHandle(base, &data->handle,
					 spi_mcux_master_transfer_callback,
					 data);

	LPSPI_SetDummyData(base, 0);

	data->ctx.config = spi_cfg;

	return 0;
}

#ifdef CONFIG_SPI_MCUX_LPSPI_DMA

/* This function is executed in the interrupt context */
static void spi_mcux_dma_callback(const struct device *dev, void *arg,
			 uint32_t channel, int status)
{
	/* arg directly holds the spi device */
	struct spi_mcux_data *data = arg;

	if (status != 0) {
		LOG_ERR("DMA callback error with channel %d.", channel);
		data->status_flags |= SPI_MCUX_LPSPI_DMA_ERROR_FLAG;
	} else {
		/* identify the origin of this callback */
		if (channel == data->dma_tx.channel) {
			/* this part of the transfer ends */
			data->status_flags |= SPI_MCUX_LPSPI_DMA_TX_DONE_FLAG;
			LOG_DBG("DMA TX Block Complete");
		} else if (channel == data->dma_rx.channel) {
			/* this part of the transfer ends */
			data->status_flags |= SPI_MCUX_LPSPI_DMA_RX_DONE_FLAG;
			LOG_DBG("DMA RX Block Complete");
		} else {
			LOG_ERR("DMA callback channel %d is not valid.",
								channel);
			data->status_flags |= SPI_MCUX_LPSPI_DMA_ERROR_FLAG;
		}
	}
	spi_context_complete(&data->ctx, 0);
}

static int spi_mcux_dma_tx_load(const struct device *dev, const uint8_t *buf, size_t len)
{
	const struct spi_mcux_config *cfg = dev->config;
	struct spi_mcux_data *data = dev->data;
	struct dma_block_config *blk_cfg;
	LPSPI_Type *base = cfg->base;

	/* remember active TX DMA channel (used in callback) */
	struct stream *stream = &data->dma_tx;

	blk_cfg = &stream->dma_blk_cfg;

	/* prepare the block for this TX DMA channel */
	memset(blk_cfg, 0, sizeof(struct dma_block_config));

	if (buf == NULL) {
		/* Treat the transfer as a peripheral to peripheral one, so that DMA
		 * reads from this address each time
		 */
		blk_cfg->source_address = (uint32_t)&data->dummy_tx_buffer;
		stream->dma_cfg.channel_direction = PERIPHERAL_TO_PERIPHERAL;
	} else {
		/* tx direction has memory as source and periph as dest. */
		blk_cfg->source_address = (uint32_t)buf;
		stream->dma_cfg.channel_direction = MEMORY_TO_PERIPHERAL;
	}
	/* Enable scatter/gather */
	blk_cfg->source_gather_en = 1;
	/* Dest is LPSPI tx fifo */
	blk_cfg->dest_address = LPSPI_GetTxRegisterAddress(base);
	blk_cfg->block_size = len;
	/* Transfer 1 byte each DMA loop */
	stream->dma_cfg.source_burst_length = 1;

	stream->dma_cfg.head_block = &stream->dma_blk_cfg;
	/* give the client dev as arg, as the callback comes from the dma */
	stream->dma_cfg.user_data = data;
	/* pass our client origin to the dma: data->dma_tx.dma_channel */
	return dma_config(data->dma_tx.dma_dev, data->dma_tx.channel,
			&stream->dma_cfg);
}

static int spi_mcux_dma_rx_load(const struct device *dev, uint8_t *buf,
				 size_t len)
{
	const struct spi_mcux_config *cfg = dev->config;
	struct spi_mcux_data *data = dev->data;
	struct dma_block_config *blk_cfg;
	LPSPI_Type *base = cfg->base;

	/* retrieve active RX DMA channel (used in callback) */
	struct stream *stream = &data->dma_rx;

	blk_cfg = &stream->dma_blk_cfg;

	/* prepare the block for this RX DMA channel */
	memset(blk_cfg, 0, sizeof(struct dma_block_config));

	if (buf == NULL) {
		/* Treat the transfer as a peripheral to peripheral one, so that DMA
		 * reads from this address each time
		 */
		blk_cfg->dest_address = (uint32_t)&data->dummy_rx_buffer;
		stream->dma_cfg.channel_direction = PERIPHERAL_TO_PERIPHERAL;
	} else {
		/* rx direction has periph as source and mem as dest. */
		blk_cfg->dest_address = (uint32_t)buf;
		stream->dma_cfg.channel_direction = PERIPHERAL_TO_MEMORY;
	}
	blk_cfg->block_size = len;
	/* Enable scatter/gather */
	blk_cfg->dest_scatter_en = 1;
	/* Source is LPSPI rx fifo */
	blk_cfg->source_address = LPSPI_GetRxRegisterAddress(base);
	stream->dma_cfg.source_burst_length = 1;

	stream->dma_cfg.head_block = blk_cfg;
	stream->dma_cfg.user_data = data;

	/* pass our client origin to the dma: data->dma_rx.channel */
	return dma_config(data->dma_rx.dma_dev, data->dma_rx.channel,
			&stream->dma_cfg);
}

static int wait_dma_rx_tx_done(const struct device *dev)
{
	struct spi_mcux_data *data = dev->data;
	int ret = -1;

	while (1) {
		ret = spi_context_wait_for_completion(&data->ctx);
		if (ret) {
			LOG_DBG("Timed out waiting for SPI context to complete");
			return ret;
		}
		if (data->status_flags & SPI_MCUX_LPSPI_DMA_ERROR_FLAG) {
			return -EIO;
		}

		if ((data->status_flags & SPI_MCUX_LPSPI_DMA_DONE_FLAG) ==
			SPI_MCUX_LPSPI_DMA_DONE_FLAG) {
			LOG_DBG("DMA block completed");
			return 0;
		}
	}
}

static int transceive_dma(const struct device *dev,
		      const struct spi_config *spi_cfg,
		      const struct spi_buf_set *tx_bufs,
		      const struct spi_buf_set *rx_bufs,
		      bool asynchronous,
		      struct k_poll_signal *sig)
{
	const struct spi_mcux_config *config = dev->config;
	struct spi_mcux_data *data = dev->data;
	LPSPI_Type *base = config->base;
	int ret;
	size_t dma_size;

	spi_context_lock(&data->ctx, asynchronous, sig, spi_cfg);

	ret = spi_mcux_configure(dev, spi_cfg);
	if (ret) {
		goto out;
	}

	spi_context_buffers_setup(&data->ctx, tx_bufs, rx_bufs, 1);

	spi_context_cs_control(&data->ctx, true);

	/* DMA is fast enough watermarks are not required */
	LPSPI_SetFifoWatermarks(base, 0U, 0U);

	/* Send each spi buf via DMA, updating context as DMA completes */
	while (data->ctx.rx_len > 0 || data->ctx.tx_len > 0) {
		/* Clear status flags */
		data->status_flags = 0U;
		/* Load dma blocks of equal length */
		dma_size = MIN(data->ctx.tx_len, data->ctx.rx_len);
		if (dma_size == 0) {
			dma_size = MAX(data->ctx.tx_len, data->ctx.rx_len);
		}
		ret = spi_mcux_dma_tx_load(dev, data->ctx.tx_buf, dma_size);
		if (ret != 0) {
			goto out;
		}

		ret = spi_mcux_dma_rx_load(dev, data->ctx.rx_buf, dma_size);
		if (ret != 0) {
			goto out;
		}

		/* Start DMA */
		ret = dma_start(data->dma_tx.dma_dev, data->dma_tx.channel);
		if (ret != 0) {
			goto out;
		}
		ret = dma_start(data->dma_rx.dma_dev, data->dma_rx.channel);
		if (ret != 0) {
			goto out;
		}

		/* Enable DMA Requests */
		LPSPI_EnableDMA(base, kLPSPI_TxDmaEnable | kLPSPI_RxDmaEnable);

		/* Wait for DMA to finish */
		ret = wait_dma_rx_tx_done(dev);
		if (ret != 0) {
			goto out;
		}

		while ((LPSPI_GetStatusFlags(base) & kLPSPI_ModuleBusyFlag)) {
			/* wait until module is idle */
		}

		/* Disable DMA */
		LPSPI_DisableDMA(base, kLPSPI_TxDmaEnable | kLPSPI_RxDmaEnable);

		/* Update SPI contexts with amount of data we just sent */
		spi_context_update_tx(&data->ctx, 1, dma_size);
		spi_context_update_rx(&data->ctx, 1, dma_size);
	}

	spi_context_cs_control(&data->ctx, false);

out:
	spi_context_release(&data->ctx, ret);

	return ret;
}

#endif

static int transceive(const struct device *dev,
		      const struct spi_config *spi_cfg,
		      const struct spi_buf_set *tx_bufs,
		      const struct spi_buf_set *rx_bufs,
		      bool asynchronous,
		      struct k_poll_signal *signal)
{
	struct spi_mcux_data *data = dev->data;
	int ret;

	spi_context_lock(&data->ctx, asynchronous, signal, spi_cfg);

	ret = spi_mcux_configure(dev, spi_cfg);
	if (ret) {
		goto out;
	}

	spi_context_buffers_setup(&data->ctx, tx_bufs, rx_bufs, 1);

	spi_context_cs_control(&data->ctx, true);

	spi_mcux_transfer_next_packet(dev);

	ret = spi_context_wait_for_completion(&data->ctx);
out:
	spi_context_release(&data->ctx, ret);

	return ret;
}

static int spi_mcux_transceive(const struct device *dev,
			       const struct spi_config *spi_cfg,
			       const struct spi_buf_set *tx_bufs,
			       const struct spi_buf_set *rx_bufs)
{
#ifdef CONFIG_SPI_MCUX_LPSPI_DMA
	return transceive_dma(dev, spi_cfg, tx_bufs, rx_bufs, false, NULL);
#endif /* CONFIG_SPI_MCUX_LPSPI_DMA */
	return transceive(dev, spi_cfg, tx_bufs, rx_bufs, false, NULL);
}

#ifdef CONFIG_SPI_ASYNC
static int spi_mcux_transceive_async(const struct device *dev,
				     const struct spi_config *spi_cfg,
				     const struct spi_buf_set *tx_bufs,
				     const struct spi_buf_set *rx_bufs,
				     struct k_poll_signal *async)
{
	return transceive(dev, spi_cfg, tx_bufs, rx_bufs, true, async);
}
#endif /* CONFIG_SPI_ASYNC */

static int spi_mcux_release(const struct device *dev,
			    const struct spi_config *spi_cfg)
{
	struct spi_mcux_data *data = dev->data;

	spi_context_unlock_unconditionally(&data->ctx);

	return 0;
}

static int spi_mcux_init(const struct device *dev)
{
	int err;
	const struct spi_mcux_config *config = dev->config;
	struct spi_mcux_data *data = dev->data;

	config->irq_config_func(dev);

	err = spi_context_cs_configure_all(&data->ctx);
	if (err < 0) {
		return err;
	}

	spi_context_unlock_unconditionally(&data->ctx);

	data->dev = dev;

#ifdef CONFIG_SPI_MCUX_LPSPI_DMA
	if (!device_is_ready(data->dma_tx.dma_dev)) {
		LOG_ERR("%s device is not ready", data->dma_tx.dma_dev->name);
		return -ENODEV;
	}

	if (!device_is_ready(data->dma_rx.dma_dev)) {
		LOG_ERR("%s device is not ready", data->dma_rx.dma_dev->name);
		return -ENODEV;
	}
#endif /* CONFIG_SPI_MCUX_LPSPI_DMA */

	spi_context_unlock_unconditionally(&data->ctx);

	return 0;
}

static const struct spi_driver_api spi_mcux_driver_api = {
	.transceive = spi_mcux_transceive,
#ifdef CONFIG_SPI_ASYNC
	.transceive_async = spi_mcux_transceive_async,
#endif
	.release = spi_mcux_release,
};

#ifdef CONFIG_SPI_MCUX_LPSPI_DMA
#define SPI_DMA_CHANNELS(n)		\
	.dma_tx = {						\
		.dma_dev = DEVICE_DT_GET(DT_INST_DMAS_CTLR_BY_NAME(n, tx)), \
		.channel =					\
			DT_INST_DMAS_CELL_BY_NAME(n, tx, mux),	\
		.dma_cfg = {					\
			.channel_direction = MEMORY_TO_PERIPHERAL,	\
			.dma_callback = spi_mcux_dma_callback,		\
			.source_data_size = 1,				\
			.dest_data_size = 1,				\
			.block_count = 1,		\
			.dma_slot = DT_INST_DMAS_CELL_BY_NAME(n, tx, source) \
		}							\
	},								\
	.dma_rx = {						\
		.dma_dev = DEVICE_DT_GET(DT_INST_DMAS_CTLR_BY_NAME(n, rx)), \
		.channel =					\
			DT_INST_DMAS_CELL_BY_NAME(n, rx, mux),	\
		.dma_cfg = {				\
			.channel_direction = PERIPHERAL_TO_MEMORY,	\
			.dma_callback = spi_mcux_dma_callback,		\
			.source_data_size = 1,				\
			.dest_data_size = 1,				\
			.block_count = 1,		\
			.dma_slot = DT_INST_DMAS_CELL_BY_NAME(n, rx, source) \
		}							\
	}
#else
#define SPI_DMA_CHANNELS(n)
#endif

#define SPI_MCUX_LPSPI_INIT(n)						\
	static void spi_mcux_config_func_##n(const struct device *dev);	\
									\
	static const struct spi_mcux_config spi_mcux_config_##n = {	\
		.base = (LPSPI_Type *) DT_INST_REG_ADDR(n),		\
		.clock_dev = DEVICE_DT_GET(DT_INST_CLOCKS_CTLR(n)),	\
		.clock_subsys =						\
		(clock_control_subsys_t)DT_INST_CLOCKS_CELL(n, name),	\
		.irq_config_func = spi_mcux_config_func_##n,		\
		.pcs_sck_delay = UTIL_AND(				\
			DT_INST_NODE_HAS_PROP(n, pcs_sck_delay),	\
			DT_INST_PROP(n, pcs_sck_delay)),		\
		.sck_pcs_delay = UTIL_AND(				\
			DT_INST_NODE_HAS_PROP(n, sck_pcs_delay),	\
			DT_INST_PROP(n, sck_pcs_delay)),		\
		.transfer_delay = UTIL_AND(				\
			DT_INST_NODE_HAS_PROP(n, transfer_delay),	\
			DT_INST_PROP(n, transfer_delay)),		\
	};								\
									\
	static struct spi_mcux_data spi_mcux_data_##n = {		\
		SPI_CONTEXT_INIT_LOCK(spi_mcux_data_##n, ctx),		\
		SPI_CONTEXT_INIT_SYNC(spi_mcux_data_##n, ctx),		\
		SPI_CONTEXT_CS_GPIOS_INITIALIZE(DT_DRV_INST(n), ctx)	\
		SPI_DMA_CHANNELS(n)		\
	};								\
									\
	DEVICE_DT_INST_DEFINE(n, &spi_mcux_init, NULL,			\
			    &spi_mcux_data_##n,				\
			    &spi_mcux_config_##n, POST_KERNEL,		\
			    CONFIG_SPI_INIT_PRIORITY,			\
			    &spi_mcux_driver_api);			\
									\
	static void spi_mcux_config_func_##n(const struct device *dev)	\
	{								\
		IRQ_CONNECT(DT_INST_IRQN(n), DT_INST_IRQ(n, priority),	\
			    spi_mcux_isr, DEVICE_DT_INST_GET(n), 0);	\
									\
		irq_enable(DT_INST_IRQN(n));				\
	}

DT_INST_FOREACH_STATUS_OKAY(SPI_MCUX_LPSPI_INIT)