drivers/dma/dma_stm32_bdma.c

/*
 * Copyright (c) 2023 Jeroen van Dooren, Nobleo Technology
 *
 * SPDX-License-Identifier: Apache-2.0
 */

/**
 * @brief Common part of BDMA drivers for stm32.
 */

#include "dma_stm32_bdma.h"

#include <zephyr/init.h>
#include <zephyr/drivers/clock_control.h>
#include <zephyr/drivers/dma/dma_stm32.h>

#include <zephyr/logging/log.h>
#include <zephyr/irq.h>
LOG_MODULE_REGISTER(dma_stm32_bdma, CONFIG_DMA_LOG_LEVEL);

#define DT_DRV_COMPAT st_stm32_bdma

#define BDMA_STM32_0_CHANNEL_COUNT 8

static const uint32_t table_m_size[] = {
	LL_BDMA_MDATAALIGN_BYTE,
	LL_BDMA_MDATAALIGN_HALFWORD,
	LL_BDMA_MDATAALIGN_WORD,
};

static const uint32_t table_p_size[] = {
	LL_BDMA_PDATAALIGN_BYTE,
	LL_BDMA_PDATAALIGN_HALFWORD,
	LL_BDMA_PDATAALIGN_WORD,
};

uint32_t bdma_stm32_id_to_channel(uint32_t id)
{
	static const uint32_t channel_nr[] = {
		LL_BDMA_CHANNEL_0,
		LL_BDMA_CHANNEL_1,
		LL_BDMA_CHANNEL_2,
		LL_BDMA_CHANNEL_3,
		LL_BDMA_CHANNEL_4,
		LL_BDMA_CHANNEL_5,
		LL_BDMA_CHANNEL_6,
		LL_BDMA_CHANNEL_7,
	};

	__ASSERT_NO_MSG(id < ARRAY_SIZE(channel_nr));

	return channel_nr[id];
}

#if !defined(CONFIG_DMAMUX_STM32)
uint32_t bdma_stm32_slot_to_channel(uint32_t slot)
{
	static const uint32_t channel_nr[] = {
		LL_BDMA_CHANNEL_0,
		LL_BDMA_CHANNEL_1,
		LL_BDMA_CHANNEL_2,
		LL_BDMA_CHANNEL_3,
		LL_BDMA_CHANNEL_4,
		LL_BDMA_CHANNEL_5,
		LL_BDMA_CHANNEL_6,
		LL_BDMA_CHANNEL_7,
	};

	__ASSERT_NO_MSG(slot < ARRAY_SIZE(channel_nr));

	return channel_nr[slot];
}
#endif

void bdma_stm32_clear_ht(BDMA_TypeDef *DMAx, uint32_t id)
{
	static const bdma_stm32_clear_flag_func func[] = {
		LL_BDMA_ClearFlag_HT0,
		LL_BDMA_ClearFlag_HT1,
		LL_BDMA_ClearFlag_HT2,
		LL_BDMA_ClearFlag_HT3,
		LL_BDMA_ClearFlag_HT4,
		LL_BDMA_ClearFlag_HT5,
		LL_BDMA_ClearFlag_HT6,
		LL_BDMA_ClearFlag_HT7,
	};

	__ASSERT_NO_MSG(id < ARRAY_SIZE(func));

	func[id](DMAx);
}

void bdma_stm32_clear_tc(BDMA_TypeDef *DMAx, uint32_t id)
{
	static const bdma_stm32_clear_flag_func func[] = {
		LL_BDMA_ClearFlag_TC0,
		LL_BDMA_ClearFlag_TC1,
		LL_BDMA_ClearFlag_TC2,
		LL_BDMA_ClearFlag_TC3,
		LL_BDMA_ClearFlag_TC4,
		LL_BDMA_ClearFlag_TC5,
		LL_BDMA_ClearFlag_TC6,
		LL_BDMA_ClearFlag_TC7,
	};

	__ASSERT_NO_MSG(id < ARRAY_SIZE(func));

	func[id](DMAx);
}

bool bdma_stm32_is_ht_active(BDMA_TypeDef *DMAx, uint32_t id)
{
	static const bdma_stm32_check_flag_func func[] = {
		LL_BDMA_IsActiveFlag_HT0,
		LL_BDMA_IsActiveFlag_HT1,
		LL_BDMA_IsActiveFlag_HT2,
		LL_BDMA_IsActiveFlag_HT3,
		LL_BDMA_IsActiveFlag_HT4,
		LL_BDMA_IsActiveFlag_HT5,
		LL_BDMA_IsActiveFlag_HT6,
		LL_BDMA_IsActiveFlag_HT7,
	};

	__ASSERT_NO_MSG(id < ARRAY_SIZE(func));

	return func[id](DMAx);
}

bool bdma_stm32_is_tc_active(BDMA_TypeDef *DMAx, uint32_t id)
{
	static const bdma_stm32_check_flag_func func[] = {
		LL_BDMA_IsActiveFlag_TC0,
		LL_BDMA_IsActiveFlag_TC1,
		LL_BDMA_IsActiveFlag_TC2,
		LL_BDMA_IsActiveFlag_TC3,
		LL_BDMA_IsActiveFlag_TC4,
		LL_BDMA_IsActiveFlag_TC5,
		LL_BDMA_IsActiveFlag_TC6,
		LL_BDMA_IsActiveFlag_TC7,
	};

	__ASSERT_NO_MSG(id < ARRAY_SIZE(func));

	return func[id](DMAx);
}

void bdma_stm32_clear_te(BDMA_TypeDef *DMAx, uint32_t id)
{
	static const bdma_stm32_clear_flag_func func[] = {
		LL_BDMA_ClearFlag_TE0,
		LL_BDMA_ClearFlag_TE1,
		LL_BDMA_ClearFlag_TE2,
		LL_BDMA_ClearFlag_TE3,
		LL_BDMA_ClearFlag_TE4,
		LL_BDMA_ClearFlag_TE5,
		LL_BDMA_ClearFlag_TE6,
		LL_BDMA_ClearFlag_TE7,
	};

	__ASSERT_NO_MSG(id < ARRAY_SIZE(func));

	func[id](DMAx);
}

void bdma_stm32_clear_gi(BDMA_TypeDef *DMAx, uint32_t id)
{
	static const bdma_stm32_clear_flag_func func[] = {
		LL_BDMA_ClearFlag_GI0,
		LL_BDMA_ClearFlag_GI1,
		LL_BDMA_ClearFlag_GI2,
		LL_BDMA_ClearFlag_GI3,
		LL_BDMA_ClearFlag_GI4,
		LL_BDMA_ClearFlag_GI5,
		LL_BDMA_ClearFlag_GI6,
		LL_BDMA_ClearFlag_GI7,
	};

	__ASSERT_NO_MSG(id < ARRAY_SIZE(func));

	func[id](DMAx);
}

bool bdma_stm32_is_te_active(BDMA_TypeDef *DMAx, uint32_t id)
{
	static const bdma_stm32_check_flag_func func[] = {
		LL_BDMA_IsActiveFlag_TE0,
		LL_BDMA_IsActiveFlag_TE1,
		LL_BDMA_IsActiveFlag_TE2,
		LL_BDMA_IsActiveFlag_TE3,
		LL_BDMA_IsActiveFlag_TE4,
		LL_BDMA_IsActiveFlag_TE5,
		LL_BDMA_IsActiveFlag_TE6,
		LL_BDMA_IsActiveFlag_TE7,
	};

	__ASSERT_NO_MSG(id < ARRAY_SIZE(func));

	return func[id](DMAx);
}

bool bdma_stm32_is_gi_active(BDMA_TypeDef *DMAx, uint32_t id)
{
	static const bdma_stm32_check_flag_func func[] = {
		LL_BDMA_IsActiveFlag_GI0,
		LL_BDMA_IsActiveFlag_GI1,
		LL_BDMA_IsActiveFlag_GI2,
		LL_BDMA_IsActiveFlag_GI3,
		LL_BDMA_IsActiveFlag_GI4,
		LL_BDMA_IsActiveFlag_GI5,
		LL_BDMA_IsActiveFlag_GI6,
		LL_BDMA_IsActiveFlag_GI7,
	};

	__ASSERT_NO_MSG(id < ARRAY_SIZE(func));

	return func[id](DMAx);
}

void stm32_bdma_dump_channel_irq(BDMA_TypeDef *dma, uint32_t id)
{
	LOG_INF("te: %d, ht: %d, tc: %d, gi: %d",
		bdma_stm32_is_te_active(dma, id),
		bdma_stm32_is_ht_active(dma, id),
		bdma_stm32_is_tc_active(dma, id),
		bdma_stm32_is_gi_active(dma, id));
}

inline bool stm32_bdma_is_tc_irq_active(BDMA_TypeDef *dma, uint32_t id)
{
	return LL_BDMA_IsEnabledIT_TC(dma, bdma_stm32_id_to_channel(id)) &&
	       bdma_stm32_is_tc_active(dma, id);
}

inline bool stm32_bdma_is_ht_irq_active(BDMA_TypeDef *dma, uint32_t id)
{
	return LL_BDMA_IsEnabledIT_HT(dma, bdma_stm32_id_to_channel(id)) &&
	       bdma_stm32_is_ht_active(dma, id);
}

static inline bool stm32_bdma_is_te_irq_active(BDMA_TypeDef *dma, uint32_t id)
{
	return LL_BDMA_IsEnabledIT_TE(dma, bdma_stm32_id_to_channel(id)) &&
	       bdma_stm32_is_te_active(dma, id);
}

bool stm32_bdma_is_irq_active(BDMA_TypeDef *dma, uint32_t id)
{
	return stm32_bdma_is_tc_irq_active(dma, id) ||
	       stm32_bdma_is_ht_irq_active(dma, id) ||
	       stm32_bdma_is_te_irq_active(dma, id);
}

void stm32_bdma_clear_channel_irq(BDMA_TypeDef *dma, uint32_t id)
{
	bdma_stm32_clear_gi(dma, id);
	bdma_stm32_clear_tc(dma, id);
	bdma_stm32_clear_ht(dma, id);
	bdma_stm32_clear_te(dma, id);
}

bool stm32_bdma_is_enabled_channel(BDMA_TypeDef *dma, uint32_t id)
{
	if (LL_BDMA_IsEnabledChannel(dma, bdma_stm32_id_to_channel(id)) == 1) {
		return true;
	}
	return false;
}

int stm32_bdma_disable_channel(BDMA_TypeDef *dma, uint32_t id)
{
	LL_BDMA_DisableChannel(dma, bdma_stm32_id_to_channel(id));

	if (!LL_BDMA_IsEnabledChannel(dma, bdma_stm32_id_to_channel(id))) {
		return 0;
	}

	return -EAGAIN;
}

void stm32_bdma_enable_channel(BDMA_TypeDef *dma, uint32_t id)
{
	LL_BDMA_EnableChannel(dma, bdma_stm32_id_to_channel(id));
}

static void bdma_stm32_dump_channel_irq(const struct device *dev, uint32_t id)
{
	const struct bdma_stm32_config *config = dev->config;
	BDMA_TypeDef *dma = (BDMA_TypeDef *)(config->base);

	stm32_bdma_dump_channel_irq(dma, id);
}

static void bdma_stm32_clear_channel_irq(const struct device *dev, uint32_t id)
{
	const struct bdma_stm32_config *config = dev->config;
	BDMA_TypeDef *dma = (BDMA_TypeDef *)(config->base);

	bdma_stm32_clear_tc(dma, id);
	bdma_stm32_clear_ht(dma, id);
	stm32_bdma_clear_channel_irq(dma, id);
}

static void bdma_stm32_irq_handler(const struct device *dev, uint32_t id)
{
	const struct bdma_stm32_config *config = dev->config;
	BDMA_TypeDef *dma = (BDMA_TypeDef *)(config->base);
	struct bdma_stm32_channel *channel;
	uint32_t callback_arg;

	__ASSERT_NO_MSG(id < config->max_channels);

	channel = &config->channels[id];

	/* The busy channel is pertinent if not overridden by the HAL */
	if ((channel->hal_override != true) && (channel->busy == false)) {
		/*
		 * When DMA channel is not overridden by HAL,
		 * ignore irq if the channel is not busy anymore
		 */
		bdma_stm32_clear_channel_irq(dev, id);
		return;
	}

#ifdef CONFIG_DMAMUX_STM32
	callback_arg = channel->mux_channel;
#else
	callback_arg = id;
#endif /* CONFIG_DMAMUX_STM32 */

	if (!IS_ENABLED(CONFIG_DMAMUX_STM32)) {
		channel->busy = false;
	}

	/* the dma channel id is in range from 0..<dma-requests> */
	if (stm32_bdma_is_ht_irq_active(dma, id)) {
		/* Let HAL DMA handle flags on its own */
		if (!channel->hal_override) {
			bdma_stm32_clear_ht(dma, id);
		}
		channel->bdma_callback(dev, channel->user_data, callback_arg, 0);
	} else if (stm32_bdma_is_tc_irq_active(dma, id)) {
#ifdef CONFIG_DMAMUX_STM32
		channel->busy = false;
#endif
		/* Let HAL DMA handle flags on its own */
		if (!channel->hal_override) {
			bdma_stm32_clear_tc(dma, id);
		}
		channel->bdma_callback(dev, channel->user_data, callback_arg, 0);
	} else {
		LOG_ERR("Transfer Error.");
		bdma_stm32_dump_channel_irq(dev, id);
		bdma_stm32_clear_channel_irq(dev, id);
		channel->bdma_callback(dev, channel->user_data,
				     callback_arg, -EIO);
	}
}

static int bdma_stm32_get_priority(uint8_t priority, uint32_t *ll_priority)
{
	switch (priority) {
	case 0x0:
		*ll_priority = LL_BDMA_PRIORITY_LOW;
		break;
	case 0x1:
		*ll_priority = LL_BDMA_PRIORITY_MEDIUM;
		break;
	case 0x2:
		*ll_priority = LL_BDMA_PRIORITY_HIGH;
		break;
	case 0x3:
		*ll_priority = LL_BDMA_PRIORITY_VERYHIGH;
		break;
	default:
		LOG_ERR("Priority error. %d", priority);
		return -EINVAL;
	}

	return 0;
}

static int bdma_stm32_get_direction(enum dma_channel_direction direction,
				   uint32_t *ll_direction)
{
	switch (direction) {
	case MEMORY_TO_MEMORY:
		*ll_direction = LL_BDMA_DIRECTION_MEMORY_TO_MEMORY;
		break;
	case MEMORY_TO_PERIPHERAL:
		*ll_direction = LL_BDMA_DIRECTION_MEMORY_TO_PERIPH;
		break;
	case PERIPHERAL_TO_MEMORY:
		*ll_direction = LL_BDMA_DIRECTION_PERIPH_TO_MEMORY;
		break;
	default:
		LOG_ERR("Direction error. %d", direction);
		return -EINVAL;
	}

	return 0;
}

static int bdma_stm32_get_memory_increment(enum dma_addr_adj increment,
					  uint32_t *ll_increment)
{
	switch (increment) {
	case DMA_ADDR_ADJ_INCREMENT:
		*ll_increment = LL_BDMA_MEMORY_INCREMENT;
		break;
	case DMA_ADDR_ADJ_NO_CHANGE:
		*ll_increment = LL_BDMA_MEMORY_NOINCREMENT;
		break;
	case DMA_ADDR_ADJ_DECREMENT:
		return -ENOTSUP;
	default:
		LOG_ERR("Memory increment error. %d", increment);
		return -EINVAL;
	}

	return 0;
}

static int bdma_stm32_get_periph_increment(enum dma_addr_adj increment,
					  uint32_t *ll_increment)
{
	switch (increment) {
	case DMA_ADDR_ADJ_INCREMENT:
		*ll_increment = LL_BDMA_PERIPH_INCREMENT;
		break;
	case DMA_ADDR_ADJ_NO_CHANGE:
		*ll_increment = LL_BDMA_PERIPH_NOINCREMENT;
		break;
	case DMA_ADDR_ADJ_DECREMENT:
		return -ENOTSUP;
	default:
		LOG_ERR("Periph increment error. %d", increment);
		return -EINVAL;
	}

	return 0;
}

static int bdma_stm32_disable_channel(BDMA_TypeDef *bdma, uint32_t id)
{
	int count = 0;

	for (;;) {
		if (stm32_bdma_disable_channel(bdma, id) == 0) {
			return 0;
		}
		/* After trying for 5 seconds, give up */
		if (count++ > (5 * 1000)) {
			return -EBUSY;
		}
		k_sleep(K_MSEC(1));
	}

	return 0;
}

static bool bdma_stm32_is_valid_memory_address(const uint32_t address, const uint32_t size)
{
	/* The BDMA can only access memory addresses in SRAM4 */

	const uint32_t sram4_start = DT_REG_ADDR(DT_NODELABEL(sram4));
	const uint32_t sram4_end = sram4_start + DT_REG_SIZE(DT_NODELABEL(sram4));

	if (address < sram4_start) {
		return false;
	}

	if (address + size > sram4_end) {
		return false;
	}

	return true;
}


BDMA_STM32_EXPORT_API int bdma_stm32_configure(const struct device *dev,
					     uint32_t id,
					     struct dma_config *config)
{
	const struct bdma_stm32_config *dev_config = dev->config;
	struct bdma_stm32_channel *channel =
				&dev_config->channels[id];
	BDMA_TypeDef *bdma = (BDMA_TypeDef *)dev_config->base;
	LL_BDMA_InitTypeDef BDMA_InitStruct;
	int index;
	int ret;

	LL_BDMA_StructInit(&BDMA_InitStruct);

	if (id >= dev_config->max_channels) {
		LOG_ERR("cannot configure the bdma channel %d.", id);
		return -EINVAL;
	}

	if (channel->busy) {
		LOG_ERR("bdma channel %d is busy.", id);
		return -EBUSY;
	}

	if (bdma_stm32_disable_channel(bdma, id) != 0) {
		LOG_ERR("could not disable bdma channel %d.", id);
		return -EBUSY;
	}

	bdma_stm32_clear_channel_irq(dev, id);

	if (config->head_block->block_size > BDMA_STM32_MAX_DATA_ITEMS) {
		LOG_ERR("Data size too big: %d\n",
		       config->head_block->block_size);
		return -EINVAL;
	}

	if ((config->channel_direction == MEMORY_TO_MEMORY) &&
		(!dev_config->support_m2m)) {
		LOG_ERR("Memcopy not supported for device %s",
			dev->name);
		return -ENOTSUP;
	}

	/* support only the same data width for source and dest */
	if (config->dest_data_size != config->source_data_size) {
		LOG_ERR("source and dest data size differ.");
		return -EINVAL;
	}

	if (config->source_data_size != 4U &&
	    config->source_data_size != 2U &&
	    config->source_data_size != 1U) {
		LOG_ERR("source and dest unit size error, %d",
			config->source_data_size);
		return -EINVAL;
	}

	/*
	 * STM32's circular mode will auto reset both source address
	 * counter and destination address counter.
	 */
	if (config->head_block->source_reload_en !=
		config->head_block->dest_reload_en) {
		LOG_ERR("source_reload_en and dest_reload_en must "
			"be the same.");
		return -EINVAL;
	}

	channel->busy		= true;
	channel->bdma_callback	= config->dma_callback;
	channel->direction	= config->channel_direction;
	channel->user_data	= config->user_data;
	channel->src_size	= config->source_data_size;
	channel->dst_size	= config->dest_data_size;

	/* check dest or source memory address, warn if 0 */
	if (config->head_block->source_address == 0) {
		LOG_WRN("source_buffer address is null.");
	}

	if (config->head_block->dest_address == 0) {
		LOG_WRN("dest_buffer address is null.");
	}

	/* ensure all memory addresses are in SRAM4 */
	if (channel->direction == MEMORY_TO_PERIPHERAL || channel->direction == MEMORY_TO_MEMORY) {
		if (!bdma_stm32_is_valid_memory_address(config->head_block->source_address,
							config->head_block->block_size)) {
			LOG_ERR("invalid source address");
			return -EINVAL;
		}
	}
	if (channel->direction == PERIPHERAL_TO_MEMORY || channel->direction == MEMORY_TO_MEMORY) {
		if (!bdma_stm32_is_valid_memory_address(config->head_block->dest_address,
							config->head_block->block_size)) {
			LOG_ERR("invalid destination address");
			return -EINVAL;
		}
	}

	if (channel->direction == MEMORY_TO_PERIPHERAL) {
		BDMA_InitStruct.MemoryOrM2MDstAddress =
					config->head_block->source_address;
		BDMA_InitStruct.PeriphOrM2MSrcAddress =
					config->head_block->dest_address;
	} else {
		BDMA_InitStruct.PeriphOrM2MSrcAddress =
					config->head_block->source_address;
		BDMA_InitStruct.MemoryOrM2MDstAddress =
					config->head_block->dest_address;
	}

	uint16_t memory_addr_adj = 0, periph_addr_adj = 0;

	ret = bdma_stm32_get_priority(config->channel_priority,
				     &BDMA_InitStruct.Priority);
	if (ret < 0) {
		return ret;
	}

	ret = bdma_stm32_get_direction(config->channel_direction,
				      &BDMA_InitStruct.Direction);
	if (ret < 0) {
		return ret;
	}

	switch (config->channel_direction) {
	case MEMORY_TO_MEMORY:
	case PERIPHERAL_TO_MEMORY:
		memory_addr_adj = config->head_block->dest_addr_adj;
		periph_addr_adj = config->head_block->source_addr_adj;
		break;
	case MEMORY_TO_PERIPHERAL:
		memory_addr_adj = config->head_block->source_addr_adj;
		periph_addr_adj = config->head_block->dest_addr_adj;
		break;
	/* Direction has been asserted in bdma_stm32_get_direction. */
	default:
		LOG_ERR("Channel direction error (%d).",
				config->channel_direction);
		return -EINVAL;
	}

	ret = bdma_stm32_get_memory_increment(memory_addr_adj,
					&BDMA_InitStruct.MemoryOrM2MDstIncMode);
	if (ret < 0) {
		return ret;
	}
	ret = bdma_stm32_get_periph_increment(periph_addr_adj,
					&BDMA_InitStruct.PeriphOrM2MSrcIncMode);
	if (ret < 0) {
		return ret;
	}

	if (config->head_block->source_reload_en) {
		BDMA_InitStruct.Mode = LL_BDMA_MODE_CIRCULAR;
	} else {
		BDMA_InitStruct.Mode = LL_BDMA_MODE_NORMAL;
	}

	channel->source_periph = (channel->direction == PERIPHERAL_TO_MEMORY);

	/* set the data width, when source_data_size equals dest_data_size */
	index = find_lsb_set(config->source_data_size) - 1;
	BDMA_InitStruct.PeriphOrM2MSrcDataSize = table_p_size[index];
	index = find_lsb_set(config->dest_data_size) - 1;
	BDMA_InitStruct.MemoryOrM2MDstDataSize = table_m_size[index];

	if (channel->source_periph) {
		BDMA_InitStruct.NbData = config->head_block->block_size /
					config->source_data_size;
	} else {
		BDMA_InitStruct.NbData = config->head_block->block_size /
					config->dest_data_size;
	}

#if defined(CONFIG_DMAMUX_STM32)
	/*
	 * with bdma mux,
	 * the request ID is stored in the dma_slot
	 */
	BDMA_InitStruct.PeriphRequest = config->dma_slot;
#endif
	LL_BDMA_Init(bdma, bdma_stm32_id_to_channel(id), &BDMA_InitStruct);

	LL_BDMA_EnableIT_TC(bdma, bdma_stm32_id_to_channel(id));

	/* Enable Half-Transfer irq if circular mode is enabled */
	if (config->head_block->source_reload_en) {
		LL_BDMA_EnableIT_HT(bdma, bdma_stm32_id_to_channel(id));
	}

	return ret;
}

BDMA_STM32_EXPORT_API int bdma_stm32_reload(const struct device *dev, uint32_t id,
					  uint32_t src, uint32_t dst,
					  size_t size)
{
	const struct bdma_stm32_config *config = dev->config;
	BDMA_TypeDef *bdma = (BDMA_TypeDef *)(config->base);
	struct bdma_stm32_channel *channel;

	if (id >= config->max_channels) {
		return -EINVAL;
	}

	channel = &config->channels[id];

	if (bdma_stm32_disable_channel(bdma, id) != 0) {
		return -EBUSY;
	}

	switch (channel->direction) {
	case MEMORY_TO_PERIPHERAL:
		LL_BDMA_SetMemoryAddress(bdma, bdma_stm32_id_to_channel(id), src);
		LL_BDMA_SetPeriphAddress(bdma, bdma_stm32_id_to_channel(id), dst);
		break;
	case MEMORY_TO_MEMORY:
	case PERIPHERAL_TO_MEMORY:
		LL_BDMA_SetPeriphAddress(bdma, bdma_stm32_id_to_channel(id), src);
		LL_BDMA_SetMemoryAddress(bdma, bdma_stm32_id_to_channel(id), dst);
		break;
	default:
		return -EINVAL;
	}

	if (channel->source_periph) {
		LL_BDMA_SetDataLength(bdma, bdma_stm32_id_to_channel(id),
				     size / channel->src_size);
	} else {
		LL_BDMA_SetDataLength(bdma, bdma_stm32_id_to_channel(id),
				     size / channel->dst_size);
	}

	/* When reloading the dma, the channel is busy again before enabling */
	channel->busy = true;

	stm32_bdma_enable_channel(bdma, id);

	return 0;
}

BDMA_STM32_EXPORT_API int bdma_stm32_start(const struct device *dev, uint32_t id)
{
	const struct bdma_stm32_config *config = dev->config;
	BDMA_TypeDef *bdma = (BDMA_TypeDef *)(config->base);
	struct bdma_stm32_channel *channel;

	/* Only M2P or M2M mode can be started manually. */
	if (id >= config->max_channels) {
		return -EINVAL;
	}

	/* Repeated start : return now if channel is already started */
	if (stm32_bdma_is_enabled_channel(bdma, id)) {
		return 0;
	}

	/* When starting the dma, the channel is busy before enabling */
	channel = &config->channels[id];
	channel->busy = true;

	bdma_stm32_clear_channel_irq(dev, id);
	stm32_bdma_enable_channel(bdma, id);

	return 0;
}

BDMA_STM32_EXPORT_API int bdma_stm32_stop(const struct device *dev, uint32_t id)
{
	const struct bdma_stm32_config *config = dev->config;
	struct bdma_stm32_channel *channel = &config->channels[id];
	BDMA_TypeDef *bdma = (BDMA_TypeDef *)(config->base);

	if (id >= config->max_channels) {
		return -EINVAL;
	}

	/* Repeated stop : return now if channel is already stopped */
	if (!stm32_bdma_is_enabled_channel(bdma, id)) {
		return 0;
	}

	/* in bdma_stm32_configure, enabling is done regardless of defines */
	LL_BDMA_DisableIT_TC(bdma, bdma_stm32_id_to_channel(id));
	LL_BDMA_DisableIT_HT(bdma, bdma_stm32_id_to_channel(id));

	bdma_stm32_disable_channel(bdma, id);
	bdma_stm32_clear_channel_irq(dev, id);

	/* Finally, flag channel as free */
	channel->busy = false;

	return 0;
}

static int bdma_stm32_init(const struct device *dev)
{
	const struct bdma_stm32_config *config = dev->config;
	const struct device *const clk = DEVICE_DT_GET(STM32_CLOCK_CONTROL_NODE);

	if (!device_is_ready(clk)) {
		LOG_ERR("clock control device not ready");
		return -ENODEV;
	}

	if (clock_control_on(clk,
		(clock_control_subsys_t) &config->pclken) != 0) {
		LOG_ERR("clock op failed\n");
		return -EIO;
	}

	config->config_irq(dev);

	for (uint32_t i = 0; i < config->max_channels; i++) {
		config->channels[i].busy = false;
#ifdef CONFIG_DMAMUX_STM32
		/* each further channel->mux_channel is fixed here */
		config->channels[i].mux_channel = i + config->offset;
#endif /* CONFIG_DMAMUX_STM32 */
	}

	((struct bdma_stm32_data *)dev->data)->dma_ctx.magic = 0;
	((struct bdma_stm32_data *)dev->data)->dma_ctx.dma_channels = 0;
	((struct bdma_stm32_data *)dev->data)->dma_ctx.atomic = 0;

	/* The BDMA can only access SRAM4 and assumes it's nocachable
	 * This check verifies that the non-cachable flag is set in the DTS.
	 * For example:
	 *	&sram4 {
	 *		zephyr,memory-region-mpu = "RAM_NOCACHE";
	 *	};
	 */
#if DT_NODE_HAS_PROP(DT_NODELABEL(sram4), zephyr_memory_region_mpu)
	if (strcmp(DT_PROP(DT_NODELABEL(sram4), zephyr_memory_region_mpu), "RAM_NOCACHE") != 0) {
		LOG_ERR("SRAM4 is not set as non-cachable.");
		return -EIO;
	}
#else
#error "BDMA driver expects SRAM4 to be set as RAM_NOCACHE in DTS"
#endif

	return 0;
}

BDMA_STM32_EXPORT_API int bdma_stm32_get_status(const struct device *dev,
				uint32_t id, struct dma_status *stat)
{
	const struct bdma_stm32_config *config = dev->config;
	BDMA_TypeDef *bdma = (BDMA_TypeDef *)(config->base);
	struct bdma_stm32_channel *channel;

	if (id >= config->max_channels) {
		return -EINVAL;
	}

	channel = &config->channels[id];
	stat->pending_length = LL_BDMA_GetDataLength(bdma, bdma_stm32_id_to_channel(id));
	stat->dir = channel->direction;
	stat->busy = channel->busy;

	return 0;
}

static const struct dma_driver_api dma_funcs = {
	.reload		 = bdma_stm32_reload,
	.config		 = bdma_stm32_configure,
	.start		 = bdma_stm32_start,
	.stop		 = bdma_stm32_stop,
	.get_status	 = bdma_stm32_get_status,
};

#ifdef CONFIG_DMAMUX_STM32
#define BDMA_STM32_OFFSET_INIT(index)			\
	.offset = DT_INST_PROP(index, dma_offset),
#else
#define BDMA_STM32_OFFSET_INIT(index)
#endif /* CONFIG_DMAMUX_STM32 */

#define BDMA_STM32_INIT_DEV(index)					\
static struct bdma_stm32_channel					\
	bdma_stm32_channels_##index[BDMA_STM32_##index##_CHANNEL_COUNT];\
									\
const struct bdma_stm32_config bdma_stm32_config_##index = {		\
	.pclken = { .bus = DT_INST_CLOCKS_CELL(index, bus),		\
		    .enr = DT_INST_CLOCKS_CELL(index, bits) },		\
	.config_irq = bdma_stm32_config_irq_##index,			\
	.base = DT_INST_REG_ADDR(index),				\
	.support_m2m = DT_INST_PROP(index, st_mem2mem),			\
	.max_channels = BDMA_STM32_##index##_CHANNEL_COUNT,		\
	.channels = bdma_stm32_channels_##index,			\
	BDMA_STM32_OFFSET_INIT(index)					\
};									\
									\
static struct bdma_stm32_data bdma_stm32_data_##index = {		\
};									\
									\
DEVICE_DT_INST_DEFINE(index,							\
		    &bdma_stm32_init,						\
		    NULL,							\
		    &bdma_stm32_data_##index, &bdma_stm32_config_##index,	\
		    PRE_KERNEL_1, CONFIG_KERNEL_INIT_PRIORITY_DEFAULT,		\
		    &dma_funcs)

#define BDMA_STM32_DEFINE_IRQ_HANDLER(bdma, chan)			\
static void bdma_stm32_irq_##bdma##_##chan(const struct device *dev)	\
{									\
	bdma_stm32_irq_handler(dev, chan);				\
}


#define BDMA_STM32_IRQ_CONNECT(bdma, chan)				\
	do {								\
		IRQ_CONNECT(DT_INST_IRQ_BY_IDX(bdma, chan, irq),	\
			    DT_INST_IRQ_BY_IDX(bdma, chan, priority),	\
			    bdma_stm32_irq_##bdma##_##chan,		\
			    DEVICE_DT_INST_GET(bdma), 0);		\
		irq_enable(DT_INST_IRQ_BY_IDX(bdma, chan, irq));	\
	} while (false)


#if DT_NODE_HAS_STATUS(DT_DRV_INST(0), okay)

#define BDMA_STM32_DEFINE_IRQ_HANDLER_GEN(i, _) \
	BDMA_STM32_DEFINE_IRQ_HANDLER(0, i)
LISTIFY(DT_NUM_IRQS(DT_DRV_INST(0)), BDMA_STM32_DEFINE_IRQ_HANDLER_GEN, (;));

static void bdma_stm32_config_irq_0(const struct device *dev)
{
	ARG_UNUSED(dev);

	#define BDMA_STM32_IRQ_CONNECT_GEN(i, _) \
		BDMA_STM32_IRQ_CONNECT(0, i);
	LISTIFY(DT_NUM_IRQS(DT_DRV_INST(0)), BDMA_STM32_IRQ_CONNECT_GEN, (;));
}

BDMA_STM32_INIT_DEV(0);

#endif /* DT_NODE_HAS_STATUS(DT_DRV_INST(0), okay) */