/*
 * Copyright (c) 2016 BayLibre, SAS
 *
 * SPDX-License-Identifier: Apache-2.0
 */

#define DT_DRV_COMPAT st_stm32_spi

#define LOG_LEVEL CONFIG_SPI_LOG_LEVEL
#include <logging/log.h>
LOG_MODULE_REGISTER(spi_ll_stm32);

#include <sys/util.h>
#include <kernel.h>
#include <soc.h>
#include <errno.h>
#include <drivers/spi.h>
#include <toolchain.h>
#ifdef CONFIG_SPI_STM32_DMA
#include <dt-bindings/dma/stm32_dma.h>
#include <drivers/dma.h>
#endif
#include <drivers/clock_control/stm32_clock_control.h>
#include <drivers/clock_control.h>

#include "spi_ll_stm32.h"

#define DEV_CFG(dev)						\
(const struct spi_stm32_config * const)(dev->config_info)

#define DEV_DATA(dev)					\
(struct spi_stm32_data * const)(dev->driver_data)

/*
 * Check for SPI_SR_FRE to determine support for TI mode frame format
 * error flag, because STM32F1 SoCs do not support it and  STM32CUBE
 * for F1 family defines an unused LL_SPI_SR_FRE.
 */
#ifdef CONFIG_SOC_SERIES_STM32MP1X
#define SPI_STM32_ERR_MSK (LL_SPI_SR_UDR | LL_SPI_SR_CRCE | LL_SPI_SR_MODF | \
			   LL_SPI_SR_OVR | LL_SPI_SR_TIFRE)
#else
#if defined(LL_SPI_SR_UDR)
#define SPI_STM32_ERR_MSK (LL_SPI_SR_UDR | LL_SPI_SR_CRCERR | LL_SPI_SR_MODF | \
			   LL_SPI_SR_OVR | LL_SPI_SR_FRE)
#elif defined(SPI_SR_FRE)
#define SPI_STM32_ERR_MSK (LL_SPI_SR_CRCERR | LL_SPI_SR_MODF | \
			   LL_SPI_SR_OVR | LL_SPI_SR_FRE)
#else
#define SPI_STM32_ERR_MSK (LL_SPI_SR_CRCERR | LL_SPI_SR_MODF | LL_SPI_SR_OVR)
#endif
#endif /* CONFIG_SOC_SERIES_STM32MP1X */


#ifdef CONFIG_SPI_STM32_DMA
/* dummy value used for transferring NOP when tx buf is null */
u32_t nop_tx;

/* This function is executed in the interrupt context */
static void dma_callback(void *arg, u32_t channel, int status)
{
	/* callback_arg directly holds the client data */
	struct spi_stm32_data *data = arg;

	if (status != 0) {
		LOG_ERR("DMA callback error with channel %d.", channel);
		data->dma_tx.transfer_complete = true;
		data->dma_rx.transfer_complete = true;
		return;
	}

	/* identify the origin of this callback */
	if (channel == data->dma_tx.channel) {
		/* this part of the transfer ends */
		data->dma_tx.transfer_complete = true;
	} else if (channel == data->dma_rx.channel) {
		/* this part of the transfer ends */
		data->dma_rx.transfer_complete = true;
	} else {
		LOG_ERR("DMA callback channel %d is not valid.", channel);
		data->dma_tx.transfer_complete = true;
		data->dma_rx.transfer_complete = true;
		return;
	}
}

static int spi_stm32_dma_tx_load(struct device *dev, const u8_t *buf,
				 size_t len)
{
	const struct spi_stm32_config *cfg = DEV_CFG(dev);
	struct spi_stm32_data *data = DEV_DATA(dev);
	struct dma_block_config blk_cfg;
	int ret;

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

	/* prepare the block for this TX DMA channel */
	memset(&blk_cfg, 0, sizeof(blk_cfg));
	blk_cfg.block_size = len;

	/* tx direction has memory as source and periph as dest. */
	if (buf == NULL) {
		nop_tx = 0;
		/* if tx buff is null, then sends NOP on the line. */
		blk_cfg.source_address = (u32_t)&nop_tx;
		blk_cfg.source_addr_adj = DMA_ADDR_ADJ_NO_CHANGE;
	} else {
		blk_cfg.source_address = (u32_t)buf;
		if (data->dma_tx.src_addr_increment) {
			blk_cfg.source_addr_adj = DMA_ADDR_ADJ_INCREMENT;
		} else {
			blk_cfg.source_addr_adj = DMA_ADDR_ADJ_NO_CHANGE;
		}
	}

	blk_cfg.dest_address = (u32_t)LL_SPI_DMA_GetRegAddr(cfg->spi);
	/* fifo mode NOT USED there */
	if (data->dma_tx.dst_addr_increment) {
		blk_cfg.dest_addr_adj = DMA_ADDR_ADJ_INCREMENT;
	} else {
		blk_cfg.dest_addr_adj = DMA_ADDR_ADJ_NO_CHANGE;
	}

	/* give the fifo mode from the DT */
	blk_cfg.fifo_mode_control = data->dma_tx.fifo_threshold;

	/* direction is given by the DT */
	stream->dma_cfg.head_block = &blk_cfg;
	/* give the client data as arg, as the callback comes from the dma */
	stream->dma_cfg.callback_arg = data;
	/* pass our client origin to the dma: data->dma_tx.dma_channel */
	ret = dma_config(data->dev_dma_tx, data->dma_tx.channel,
			&stream->dma_cfg);
	/* the channel is the actual stream from 0 */
	if (ret != 0) {
		return ret;
	}

	/* starting this dma transfer */
	data->dma_tx.transfer_complete = false;

	/* gives the request ID to the dma mux */
	return dma_start(data->dev_dma_tx, data->dma_tx.channel);
}

static int spi_stm32_dma_rx_load(struct device *dev, u8_t *buf, size_t len)
{
	const struct spi_stm32_config *cfg = DEV_CFG(dev);
	struct spi_stm32_data *data = DEV_DATA(dev);
	struct dma_block_config blk_cfg;
	int ret;

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

	/* prepare the block for this RX DMA channel */
	memset(&blk_cfg, 0, sizeof(blk_cfg));
	blk_cfg.block_size = len;

	/* rx direction has periph as source and mem as dest. */
	blk_cfg.dest_address = (buf != NULL) ? (u32_t)buf : (u32_t)NULL;
	blk_cfg.source_address = (u32_t)LL_SPI_DMA_GetRegAddr(cfg->spi);
	if (data->dma_rx.src_addr_increment) {
		blk_cfg.source_addr_adj = DMA_ADDR_ADJ_INCREMENT;
	} else {
		blk_cfg.source_addr_adj = DMA_ADDR_ADJ_NO_CHANGE;
	}
	if (data->dma_rx.dst_addr_increment) {
		blk_cfg.dest_addr_adj = DMA_ADDR_ADJ_INCREMENT;
	} else {
		blk_cfg.dest_addr_adj = DMA_ADDR_ADJ_NO_CHANGE;
	}

	/* give the fifo mode from the DT */
	blk_cfg.fifo_mode_control = data->dma_rx.fifo_threshold;

	/* direction is given by the DT */
	stream->dma_cfg.head_block = &blk_cfg;
	stream->dma_cfg.callback_arg = data;


	/* pass our client origin to the dma: data->dma_rx.channel */
	ret = dma_config(data->dev_dma_rx, data->dma_rx.channel,
			&stream->dma_cfg);
	/* the channel is the actual stream from 0 */
	if (ret != 0) {
		return ret;
	}

	/* starting this dma transfer */
	data->dma_rx.transfer_complete = false;

	/* gives the request ID to the dma mux */
	return dma_start(data->dev_dma_rx, data->dma_rx.channel);
}

static int spi_dma_move_buffers(struct device *dev)
{
	struct spi_stm32_data *data = DEV_DATA(dev);
	int ret;

	/* the length to transmit depends on the source data size (1,2 4) */
	data->dma_segment_len = data->ctx.tx_len
			/ data->dma_tx.dma_cfg.source_data_size;

	/* Load receive first, so it can accept transmit data */
	if (data->ctx.rx_len) {
		ret = spi_stm32_dma_rx_load(dev, data->ctx.rx_buf,
					    data->dma_segment_len);
	} else {
		ret = spi_stm32_dma_rx_load(dev, NULL, data->dma_segment_len);
	}

	if (ret != 0) {
		return ret;
	}

	if (data->ctx.tx_len) {
		ret = spi_stm32_dma_tx_load(dev, data->ctx.tx_buf,
					    data->dma_segment_len);
	} else {
		ret = spi_stm32_dma_tx_load(dev, NULL, data->dma_segment_len);
	}

	return ret;
}

static bool spi_stm32_dma_transfer_ongoing(struct spi_stm32_data *data)
{
	return ((data->dma_tx.transfer_complete != true)
		&& (data->dma_rx.transfer_complete != true));
}
#endif /* CONFIG_SPI_STM32_DMA */

/* Value to shift out when no application data needs transmitting. */
#define SPI_STM32_TX_NOP 0x00

static bool spi_stm32_transfer_ongoing(struct spi_stm32_data *data)
{
	return spi_context_tx_on(&data->ctx) || spi_context_rx_on(&data->ctx);
}

static int spi_stm32_get_err(SPI_TypeDef *spi)
{
	u32_t sr = LL_SPI_ReadReg(spi, SR);

	if (sr & SPI_STM32_ERR_MSK) {
		LOG_ERR("%s: err=%d", __func__,
			    sr & (u32_t)SPI_STM32_ERR_MSK);

		/* OVR error must be explicitly cleared */
		if (LL_SPI_IsActiveFlag_OVR(spi)) {
			LL_SPI_ClearFlag_OVR(spi);
		}

		return -EIO;
	}

	return 0;
}

/* Shift a SPI frame as master. */
static void spi_stm32_shift_m(SPI_TypeDef *spi, struct spi_stm32_data *data)
{
	u16_t tx_frame = SPI_STM32_TX_NOP;
	u16_t rx_frame;

	while (!ll_func_tx_is_empty(spi)) {
		/* NOP */
	}

#ifdef CONFIG_SOC_SERIES_STM32MP1X
	/* With the STM32MP1, if the device is the SPI master, we need to enable
	 * the start of the transfer with LL_SPI_StartMasterTransfer(spi)
	 */
	if (LL_SPI_GetMode(spi) == LL_SPI_MODE_MASTER) {
		LL_SPI_StartMasterTransfer(spi);
		while (!LL_SPI_IsActiveMasterTransfer(spi)) {
			/* NOP */
		}
	}
#endif

	if (SPI_WORD_SIZE_GET(data->ctx.config->operation) == 8) {
		if (spi_context_tx_buf_on(&data->ctx)) {
			tx_frame = UNALIGNED_GET((u8_t *)(data->ctx.tx_buf));
		}
		LL_SPI_TransmitData8(spi, tx_frame);
		/* The update is ignored if TX is off. */
		spi_context_update_tx(&data->ctx, 1, 1);
	} else {
		if (spi_context_tx_buf_on(&data->ctx)) {
			tx_frame = UNALIGNED_GET((u16_t *)(data->ctx.tx_buf));
		}
		LL_SPI_TransmitData16(spi, tx_frame);
		/* The update is ignored if TX is off. */
		spi_context_update_tx(&data->ctx, 2, 1);
	}

	while (!ll_func_rx_is_not_empty(spi)) {
		/* NOP */
	}

	if (SPI_WORD_SIZE_GET(data->ctx.config->operation) == 8) {
		rx_frame = LL_SPI_ReceiveData8(spi);
		if (spi_context_rx_buf_on(&data->ctx)) {
			UNALIGNED_PUT(rx_frame, (u8_t *)data->ctx.rx_buf);
		}
		spi_context_update_rx(&data->ctx, 1, 1);
	} else {
		rx_frame = LL_SPI_ReceiveData16(spi);
		if (spi_context_rx_buf_on(&data->ctx)) {
			UNALIGNED_PUT(rx_frame, (u16_t *)data->ctx.rx_buf);
		}
		spi_context_update_rx(&data->ctx, 2, 1);
	}
}

/* Shift a SPI frame as slave. */
static void spi_stm32_shift_s(SPI_TypeDef *spi, struct spi_stm32_data *data)
{
	if (ll_func_tx_is_empty(spi) && spi_context_tx_on(&data->ctx)) {
		u16_t tx_frame;

		if (SPI_WORD_SIZE_GET(data->ctx.config->operation) == 8) {
			tx_frame = UNALIGNED_GET((u8_t *)(data->ctx.tx_buf));
			LL_SPI_TransmitData8(spi, tx_frame);
			spi_context_update_tx(&data->ctx, 1, 1);
		} else {
			tx_frame = UNALIGNED_GET((u16_t *)(data->ctx.tx_buf));
			LL_SPI_TransmitData16(spi, tx_frame);
			spi_context_update_tx(&data->ctx, 2, 1);
		}
	} else {
		ll_func_disable_int_tx_empty(spi);
	}

	if (ll_func_rx_is_not_empty(spi) &&
	    spi_context_rx_buf_on(&data->ctx)) {
		u16_t rx_frame;

		if (SPI_WORD_SIZE_GET(data->ctx.config->operation) == 8) {
			rx_frame = LL_SPI_ReceiveData8(spi);
			UNALIGNED_PUT(rx_frame, (u8_t *)data->ctx.rx_buf);
			spi_context_update_rx(&data->ctx, 1, 1);
		} else {
			rx_frame = LL_SPI_ReceiveData16(spi);
			UNALIGNED_PUT(rx_frame, (u16_t *)data->ctx.rx_buf);
			spi_context_update_rx(&data->ctx, 2, 1);
		}
	}
}

/*
 * Without a FIFO, we can only shift out one frame's worth of SPI
 * data, and read the response back.
 *
 * TODO: support 16-bit data frames.
 */
static int spi_stm32_shift_frames(SPI_TypeDef *spi, struct spi_stm32_data *data)
{
	u16_t operation = data->ctx.config->operation;

	if (SPI_OP_MODE_GET(operation) == SPI_OP_MODE_MASTER) {
		spi_stm32_shift_m(spi, data);
	} else {
		spi_stm32_shift_s(spi, data);
	}

	return spi_stm32_get_err(spi);
}

static void spi_stm32_complete(struct spi_stm32_data *data, SPI_TypeDef *spi,
			       int status)
{
#ifdef CONFIG_SPI_STM32_INTERRUPT
	ll_func_disable_int_tx_empty(spi);
	ll_func_disable_int_rx_not_empty(spi);
	ll_func_disable_int_errors(spi);
#endif

	spi_context_cs_control(&data->ctx, false);

#if DT_HAS_COMPAT_STATUS_OKAY(st_stm32_spi_fifo)
	/* Flush RX buffer */
	while (ll_func_rx_is_not_empty(spi)) {
		(void) LL_SPI_ReceiveData8(spi);
	}
#endif

	if (LL_SPI_GetMode(spi) == LL_SPI_MODE_MASTER) {
		while (ll_func_spi_is_busy(spi)) {
			/* NOP */
		}
	}
	/* BSY flag is cleared when MODF flag is raised */
	if (LL_SPI_IsActiveFlag_MODF(spi)) {
		LL_SPI_ClearFlag_MODF(spi);
	}

	ll_func_disable_spi(spi);

#ifdef CONFIG_SPI_STM32_INTERRUPT
	spi_context_complete(&data->ctx, status);
#endif
}

#ifdef CONFIG_SPI_STM32_INTERRUPT
static void spi_stm32_isr(void *arg)
{
	struct device * const dev = (struct device *) arg;
	const struct spi_stm32_config *cfg = dev->config_info;
	struct spi_stm32_data *data = dev->driver_data;
	SPI_TypeDef *spi = cfg->spi;
	int err;

	err = spi_stm32_get_err(spi);
	if (err) {
		spi_stm32_complete(data, spi, err);
		return;
	}

	if (spi_stm32_transfer_ongoing(data)) {
		err = spi_stm32_shift_frames(spi, data);
	}

	if (err || !spi_stm32_transfer_ongoing(data)) {
		spi_stm32_complete(data, spi, err);
	}
}
#endif

static int spi_stm32_configure(struct device *dev,
			       const struct spi_config *config)
{
	const struct spi_stm32_config *cfg = DEV_CFG(dev);
	struct spi_stm32_data *data = DEV_DATA(dev);
	const u32_t scaler[] = {
		LL_SPI_BAUDRATEPRESCALER_DIV2,
		LL_SPI_BAUDRATEPRESCALER_DIV4,
		LL_SPI_BAUDRATEPRESCALER_DIV8,
		LL_SPI_BAUDRATEPRESCALER_DIV16,
		LL_SPI_BAUDRATEPRESCALER_DIV32,
		LL_SPI_BAUDRATEPRESCALER_DIV64,
		LL_SPI_BAUDRATEPRESCALER_DIV128,
		LL_SPI_BAUDRATEPRESCALER_DIV256
	};
	SPI_TypeDef *spi = cfg->spi;
	u32_t clock;
	int br;

	if (spi_context_configured(&data->ctx, config)) {
		/* Nothing to do */
		return 0;
	}

	if ((SPI_WORD_SIZE_GET(config->operation) != 8)
	    && (SPI_WORD_SIZE_GET(config->operation) != 16)) {
		return -ENOTSUP;
	}

	if (clock_control_get_rate(device_get_binding(STM32_CLOCK_CONTROL_NAME),
			(clock_control_subsys_t) &cfg->pclken, &clock) < 0) {
		LOG_ERR("Failed call clock_control_get_rate");
		return -EIO;
	}

	for (br = 1 ; br <= ARRAY_SIZE(scaler) ; ++br) {
		u32_t clk = clock >> br;

		if (clk <= config->frequency) {
			break;
		}
	}

	if (br > ARRAY_SIZE(scaler)) {
		LOG_ERR("Unsupported frequency %uHz, max %uHz, min %uHz",
			    config->frequency,
			    clock >> 1,
			    clock >> ARRAY_SIZE(scaler));
		return -EINVAL;
	}

	LL_SPI_Disable(spi);
	LL_SPI_SetBaudRatePrescaler(spi, scaler[br - 1]);

	if (SPI_MODE_GET(config->operation) & SPI_MODE_CPOL) {
		LL_SPI_SetClockPolarity(spi, LL_SPI_POLARITY_HIGH);
	} else {
		LL_SPI_SetClockPolarity(spi, LL_SPI_POLARITY_LOW);
	}

	if (SPI_MODE_GET(config->operation) & SPI_MODE_CPHA) {
		LL_SPI_SetClockPhase(spi, LL_SPI_PHASE_2EDGE);
	} else {
		LL_SPI_SetClockPhase(spi, LL_SPI_PHASE_1EDGE);
	}

	LL_SPI_SetTransferDirection(spi, LL_SPI_FULL_DUPLEX);

	if (config->operation & SPI_TRANSFER_LSB) {
		LL_SPI_SetTransferBitOrder(spi, LL_SPI_LSB_FIRST);
	} else {
		LL_SPI_SetTransferBitOrder(spi, LL_SPI_MSB_FIRST);
	}

	LL_SPI_DisableCRC(spi);

	if (config->cs || !IS_ENABLED(CONFIG_SPI_STM32_USE_HW_SS)) {
		LL_SPI_SetNSSMode(spi, LL_SPI_NSS_SOFT);
	} else {
		if (config->operation & SPI_OP_MODE_SLAVE) {
			LL_SPI_SetNSSMode(spi, LL_SPI_NSS_HARD_INPUT);
		} else {
			LL_SPI_SetNSSMode(spi, LL_SPI_NSS_HARD_OUTPUT);
		}
	}

	if (config->operation & SPI_OP_MODE_SLAVE) {
		LL_SPI_SetMode(spi, LL_SPI_MODE_SLAVE);
	} else {
		LL_SPI_SetMode(spi, LL_SPI_MODE_MASTER);
	}

	if (SPI_WORD_SIZE_GET(config->operation) ==  8) {
		LL_SPI_SetDataWidth(spi, LL_SPI_DATAWIDTH_8BIT);
	} else {
		LL_SPI_SetDataWidth(spi, LL_SPI_DATAWIDTH_16BIT);
	}

#if DT_HAS_COMPAT_STATUS_OKAY(st_stm32_spi_fifo)
	ll_func_set_fifo_threshold_8bit(spi);
#endif

#ifdef CONFIG_SPI_STM32_DMA
	/* with LL_SPI_FULL_DUPLEX mode, both tx and Rx DMA are on */
	if (data->dev_dma_tx) {
		LL_SPI_EnableDMAReq_TX(spi);
	}
	if (data->dev_dma_rx) {
		LL_SPI_EnableDMAReq_RX(spi);
	}
#endif /* CONFIG_SPI_STM32_DMA */

#ifndef CONFIG_SOC_SERIES_STM32F1X
	LL_SPI_SetStandard(spi, LL_SPI_PROTOCOL_MOTOROLA);
#endif

	/* At this point, it's mandatory to set this on the context! */
	data->ctx.config = config;

	spi_context_cs_configure(&data->ctx);

	LOG_DBG("Installed config %p: freq %uHz (div = %u),"
		    " mode %u/%u/%u, slave %u",
		    config, clock >> br, 1 << br,
		    (SPI_MODE_GET(config->operation) & SPI_MODE_CPOL) ? 1 : 0,
		    (SPI_MODE_GET(config->operation) & SPI_MODE_CPHA) ? 1 : 0,
		    (SPI_MODE_GET(config->operation) & SPI_MODE_LOOP) ? 1 : 0,
		    config->slave);

	return 0;
}

static int spi_stm32_release(struct device *dev,
			     const struct spi_config *config)
{
	struct spi_stm32_data *data = DEV_DATA(dev);

	spi_context_unlock_unconditionally(&data->ctx);

	return 0;
}

static int transceive(struct device *dev,
		      const struct spi_config *config,
		      const struct spi_buf_set *tx_bufs,
		      const struct spi_buf_set *rx_bufs,
		      bool asynchronous, struct k_poll_signal *signal)
{
	const struct spi_stm32_config *cfg = DEV_CFG(dev);
	struct spi_stm32_data *data = DEV_DATA(dev);
	SPI_TypeDef *spi = cfg->spi;
	int ret;

	if (!tx_bufs && !rx_bufs) {
		return 0;
	}

#ifndef CONFIG_SPI_STM32_INTERRUPT
	if (asynchronous) {
		return -ENOTSUP;
	}
#endif

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

	ret = spi_stm32_configure(dev, config);
	if (ret) {
		return ret;
	}

	/* Set buffers info */
	spi_context_buffers_setup(&data->ctx, tx_bufs, rx_bufs, 1);

#if DT_HAS_COMPAT_STATUS_OKAY(st_stm32_spi_fifo)
	/* Flush RX buffer */
	while (ll_func_rx_is_not_empty(spi)) {
		(void) LL_SPI_ReceiveData8(spi);
	}
#endif

	LL_SPI_Enable(spi);

	/* This is turned off in spi_stm32_complete(). */
	spi_context_cs_control(&data->ctx, true);

#ifdef CONFIG_SPI_STM32_INTERRUPT
	ll_func_enable_int_errors(spi);

	if (rx_bufs) {
		ll_func_enable_int_rx_not_empty(spi);
	}

	ll_func_enable_int_tx_empty(spi);

	ret = spi_context_wait_for_completion(&data->ctx);
#else
	do {
		ret = spi_stm32_shift_frames(spi, data);
	} while (!ret && spi_stm32_transfer_ongoing(data));

	spi_stm32_complete(data, spi, ret);

#ifdef CONFIG_SPI_SLAVE
	if (spi_context_is_slave(&data->ctx) && !ret) {
		ret = data->ctx.recv_frames;
	}
#endif /* CONFIG_SPI_SLAVE */

#endif

	spi_context_release(&data->ctx, ret);

	return ret;
}

#ifdef CONFIG_SPI_STM32_DMA
static int transceive_dma(struct device *dev,
		      const struct spi_config *config,
		      const struct spi_buf_set *tx_bufs,
		      const struct spi_buf_set *rx_bufs,
		      bool asynchronous, struct k_poll_signal *signal)
{
	const struct spi_stm32_config *cfg = DEV_CFG(dev);
	struct spi_stm32_data *data = DEV_DATA(dev);
	SPI_TypeDef *spi = cfg->spi;
	int ret;

	if (!tx_bufs && !rx_bufs) {
		return 0;
	}

	if (asynchronous) {
		return -ENOTSUP;
	}

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

	data->dma_tx.transfer_complete = false;
	data->dma_rx.transfer_complete = false;

	ret = spi_stm32_configure(dev, config);
	if (ret) {
		return ret;
	}

	/* Set buffers info */
	spi_context_buffers_setup(&data->ctx, tx_bufs, rx_bufs, 1);

	ret = spi_dma_move_buffers(dev);
	if (ret) {
		return ret;
	}

	LL_SPI_Enable(spi);

	/* store spi peripheral address */
	u32_t periph_addr = data->dma_tx.dma_cfg.head_block->dest_address;

	for (; ;) {
		/* wait for SPI busy flag */
		while (LL_SPI_IsActiveFlag_BSY(spi) == 1) {
		}

		/* once SPI is no more busy, wait for DMA transfer end */
		while (spi_stm32_dma_transfer_ongoing(data) == 1) {
		}

		if ((data->ctx.tx_count <= 1) && (data->ctx.rx_count <= 1)) {
			/* if it was the last count, then we are done */
			break;
		}

		if (data->dma_tx.transfer_complete == true) {
			LL_SPI_DisableDMAReq_TX(spi);
			/*
			 * Update the current Tx buffer, decreasing length of
			 * data->ctx.tx_count,  by its own length
			 */
			spi_context_update_tx(&data->ctx, 1, data->ctx.tx_len);
			/* keep the same dest (peripheral) */
			data->dma_tx.transfer_complete = false;
			/* and reload dma with a new source (memory) buffer */
			dma_reload(data->dev_dma_tx,
				data->dma_tx.channel,
				(u32_t)data->ctx.tx_buf,
				periph_addr,
				data->ctx.tx_len);
		}

		if (data->dma_rx.transfer_complete == true) {
			LL_SPI_DisableDMAReq_RX(spi);
			/*
			 * Update the current Rx buffer, decreasing length of
			 * data->ctx.rx_count,  by its own length
			 */
			spi_context_update_rx(&data->ctx, 1, data->ctx.rx_len);
			/* keep the same source (peripheral) */
			data->dma_rx.transfer_complete = false;
			/* and reload dma with a new dest (memory) buffer */
			dma_reload(data->dev_dma_rx,
				data->dma_rx.channel,
				periph_addr,
				(u32_t)data->ctx.rx_buf,
				data->ctx.rx_len);
		}
		LL_SPI_EnableDMAReq_RX(spi);
		LL_SPI_EnableDMAReq_TX(spi);
	}

	/* end of the transfer : all buffers sent/receceived */
	LL_SPI_Disable(spi);

	/* This is turned off in spi_stm32_complete(). */
	spi_context_cs_control(&data->ctx, true);

	spi_context_release(&data->ctx, ret);

	return ret;
}
#endif /* CONFIG_SPI_STM32_DMA */

static int spi_stm32_transceive(struct device *dev,
				const struct spi_config *config,
				const struct spi_buf_set *tx_bufs,
				const struct spi_buf_set *rx_bufs)
{
#ifdef CONFIG_SPI_STM32_DMA
	struct spi_stm32_data *data = DEV_DATA(dev);

	if ((data->dma_tx.dma_name != NULL)
	 && (data->dma_rx.dma_name != NULL)) {
		return transceive_dma(dev, config, tx_bufs, rx_bufs,
				      false, NULL);
	}
#endif /* CONFIG_SPI_STM32_DMA */
	return transceive(dev, config, tx_bufs, rx_bufs, false, NULL);
}

#ifdef CONFIG_SPI_ASYNC
static int spi_stm32_transceive_async(struct device *dev,
				      const struct spi_config *config,
				      const struct spi_buf_set *tx_bufs,
				      const struct spi_buf_set *rx_bufs,
				      struct k_poll_signal *async)
{
	return transceive(dev, config, tx_bufs, rx_bufs, true, async);
}
#endif /* CONFIG_SPI_ASYNC */

static const struct spi_driver_api api_funcs = {
	.transceive = spi_stm32_transceive,
#ifdef CONFIG_SPI_ASYNC
	.transceive_async = spi_stm32_transceive_async,
#endif
	.release = spi_stm32_release,
};

static int spi_stm32_init(struct device *dev)
{
	struct spi_stm32_data *data __attribute__((unused)) = dev->driver_data;
	const struct spi_stm32_config *cfg = dev->config_info;

	__ASSERT_NO_MSG(device_get_binding(STM32_CLOCK_CONTROL_NAME));

	if (clock_control_on(device_get_binding(STM32_CLOCK_CONTROL_NAME),
			       (clock_control_subsys_t) &cfg->pclken) != 0) {
		LOG_ERR("Could not enable SPI clock");
		return -EIO;
	}

#ifdef CONFIG_SPI_STM32_INTERRUPT
	cfg->irq_config(dev);
#endif

#ifdef CONFIG_SPI_STM32_DMA
	if (data->dma_tx.dma_name != NULL) {
		/* Get the binding to the DMA device */
		data->dev_dma_tx = device_get_binding(data->dma_tx.dma_name);
		if (!data->dev_dma_tx) {
			LOG_ERR("%s device not found", data->dma_tx.dma_name);
			return -ENODEV;
		}
	}

	if (data->dma_rx.dma_name != NULL) {
		data->dev_dma_rx = device_get_binding(data->dma_rx.dma_name);
		if (!data->dev_dma_rx) {
			LOG_ERR("%s device not found", data->dma_rx.dma_name);
			return -ENODEV;
		}
	}
#endif /* CONFIG_SPI_STM32_DMA */
	spi_context_unlock_unconditionally(&data->ctx);

	return 0;
}

#ifdef CONFIG_SPI_STM32_INTERRUPT
#define STM32_SPI_IRQ_HANDLER_DECL(id)					\
	static void spi_stm32_irq_config_func_##id(struct device *dev)
#define STM32_SPI_IRQ_HANDLER_FUNC(id)					\
	.irq_config = spi_stm32_irq_config_func_##id,
#define STM32_SPI_IRQ_HANDLER(id)					\
static void spi_stm32_irq_config_func_##id(struct device *dev)		\
{									\
	IRQ_CONNECT(DT_INST_IRQN(id),					\
		    DT_INST_IRQ(id, priority),				\
		    spi_stm32_isr, DEVICE_GET(spi_stm32_##id), 0);	\
	irq_enable(DT_INST_IRQN(id));					\
}
#else
#define STM32_SPI_IRQ_HANDLER_DECL(id)
#define STM32_SPI_IRQ_HANDLER_FUNC(id)
#define STM32_SPI_IRQ_HANDLER(id)
#endif

#define DMA_CHANNEL_CONFIG(id, dir)					\
		DT_INST_DMAS_CELL_BY_NAME(id, dir, channel_config)
#define DMA_FEATURES(id, dir)						\
		DT_INST_DMAS_CELL_BY_NAME(id, dir, features)

#define SPI_DMA_CHANNEL_INIT(index, dir, dir_cap, src_dev, dest_dev)	\
	.dma_name = DT_INST_DMAS_LABEL_BY_NAME(index, dir),		\
	.channel =							\
		DT_INST_DMAS_CELL_BY_NAME(index, dir, channel),		\
	.dma_cfg = {							\
		.dma_slot =						\
		   DT_INST_DMAS_CELL_BY_NAME(index, dir, slot),		\
		.channel_direction = STM32_DMA_CONFIG_DIRECTION(	\
					DMA_CHANNEL_CONFIG(index, dir)),       \
		.source_data_size = STM32_DMA_CONFIG_##src_dev##_DATA_SIZE(    \
					DMA_CHANNEL_CONFIG(index, dir)),       \
		.dest_data_size = STM32_DMA_CONFIG_##dest_dev##_DATA_SIZE(     \
				DMA_CHANNEL_CONFIG(index, dir)),	\
		.source_burst_length = 1, /* SINGLE transfer */		\
		.dest_burst_length = 1, /* SINGLE transfer */		\
		.channel_priority = STM32_DMA_CONFIG_PRIORITY(		\
					DMA_CHANNEL_CONFIG(index, dir)),\
		.dma_callback = dma_callback,				\
		.block_count = 2,					\
	},								\
	.src_addr_increment = STM32_DMA_CONFIG_##src_dev##_ADDR_INC(	\
				DMA_CHANNEL_CONFIG(index, dir)),	\
	.dst_addr_increment = STM32_DMA_CONFIG_##dest_dev##_ADDR_INC(	\
				DMA_CHANNEL_CONFIG(index, dir)),	\
	.transfer_complete = false,					\
	.fifo_threshold = STM32_DMA_FEATURES_FIFO_THRESHOLD(		\
					DMA_FEATURES(index, dir)),	\


#if CONFIG_SPI_STM32_DMA
#define SPI_DMA_CHANNEL(id, dir, DIR, src, dest)			\
.dma_##dir = {								\
	 COND_CODE_1(DT_INST_DMAS_HAS_NAME(id, dir),			\
		     (SPI_DMA_CHANNEL_INIT(id, dir, DIR, src, dest)),	\
		     (NULL))						\
	     },
#else
#define SPI_DMA_CHANNEL(id, dir, DIR, src, dest)
#endif

#define STM32_SPI_INIT(id)						\
STM32_SPI_IRQ_HANDLER_DECL(id);						\
									\
static const struct spi_stm32_config spi_stm32_cfg_##id = {		\
	.spi = (SPI_TypeDef *) DT_INST_REG_ADDR(id),			\
	.pclken = {							\
		.enr = DT_INST_CLOCKS_CELL(id, bits),			\
		.bus = DT_INST_CLOCKS_CELL(id, bus)			\
	},								\
	STM32_SPI_IRQ_HANDLER_FUNC(id)					\
};									\
									\
static struct spi_stm32_data spi_stm32_dev_data_##id = {		\
	SPI_CONTEXT_INIT_LOCK(spi_stm32_dev_data_##id, ctx),		\
	SPI_CONTEXT_INIT_SYNC(spi_stm32_dev_data_##id, ctx),		\
	SPI_DMA_CHANNEL(id, rx, RX, PERIPHERAL, MEMORY)			\
	SPI_DMA_CHANNEL(id, tx, TX, MEMORY, PERIPHERAL)			\
};									\
									\
DEVICE_AND_API_INIT(spi_stm32_##id, DT_INST_LABEL(id),			\
		    &spi_stm32_init,					\
		    &spi_stm32_dev_data_##id, &spi_stm32_cfg_##id,	\
		    POST_KERNEL, CONFIG_SPI_INIT_PRIORITY,		\
		    &api_funcs);					\
									\
STM32_SPI_IRQ_HANDLER(id)

DT_INST_FOREACH_STATUS_OKAY(STM32_SPI_INIT)