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

#define SYS_LOG_LEVEL CONFIG_SYS_LOG_SPI_LEVEL
#include <logging/sys_log.h>

#include <misc/util.h>
#include <kernel.h>
#include <board.h>
#include <errno.h>
#include <spi.h>

#include <clock_control/stm32_clock_control.h>
#include <clock_control.h>

#include <spi_ll_stm32.h>

#define CONFIG_CFG(cfg)						\
((const struct spi_stm32_config * const)(cfg)->dev->config->config_info)

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

#ifdef 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)
#else
#define SPI_STM32_ERR_MSK (LL_SPI_SR_CRCERR | LL_SPI_SR_MODF | \
			   LL_SPI_SR_OVR | LL_SPI_SR_FRE)
#endif

/* 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);

	return (int)(sr & SPI_STM32_ERR_MSK);
}

static inline u8_t spi_stm32_next_tx(struct spi_stm32_data *data)
{
	return spi_context_tx_on(&data->ctx) ?
		*data->ctx.tx_buf : SPI_STM32_TX_NOP;
}

/* Shift a SPI frame as master. */
static void spi_stm32_shift_m(SPI_TypeDef *spi, struct spi_stm32_data *data)
{
	u8_t tx_frame;
	u8_t rx_frame;

	tx_frame = spi_stm32_next_tx(data);
	while (!LL_SPI_IsActiveFlag_TXE(spi)) {
		/* NOP */
	}
	LL_SPI_TransmitData8(spi, tx_frame);
	/* The update is ignored if TX is off. */
	spi_context_update_tx(&data->ctx, 1, 1);

	while (!LL_SPI_IsActiveFlag_RXNE(spi)) {
		/* NOP */
	}
	rx_frame = LL_SPI_ReceiveData8(spi);
	if (spi_context_rx_on(&data->ctx)) {
		*data->ctx.rx_buf = rx_frame;
		spi_context_update_rx(&data->ctx, 1, 1);
	}
}

/* Shift a SPI frame as slave. */
static void spi_stm32_shift_s(SPI_TypeDef *spi, struct spi_stm32_data *data)
{
	u8_t tx_frame;
	u8_t rx_frame;

	tx_frame = spi_stm32_next_tx(data);
	if (LL_SPI_IsActiveFlag_TXE(spi)) {
		LL_SPI_TransmitData8(spi, tx_frame);
		/* The update is ignored if TX is off. */
		spi_context_update_tx(&data->ctx, 1, 1);
	}

	if (LL_SPI_IsActiveFlag_RXNE(spi)) {
		rx_frame = LL_SPI_ReceiveData8(spi);
		if (spi_context_rx_on(&data->ctx)) {
			*data->ctx.rx_buf = rx_frame;
			spi_context_update_rx(&data->ctx, 1, 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_SPI_DisableIT_TXE(spi);
	LL_SPI_DisableIT_RXNE(spi);
	LL_SPI_DisableIT_ERR(spi);
#endif

	spi_context_cs_control(&data->ctx, false);

#if defined(CONFIG_SOC_SERIES_STM32L4X) || defined(CONFIG_SOC_SERIES_STM32F3X)
	/* Flush RX buffer */
	while (LL_SPI_IsActiveFlag_RXNE(spi)) {
		(void) LL_SPI_ReceiveData8(spi);
	}
#endif

	if (LL_SPI_GetMode(spi) == LL_SPI_MODE_MASTER) {
		while (LL_SPI_IsActiveFlag_BSY(spi)) {
			/* NOP */
		}
	}

	LL_SPI_Disable(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->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 spi_config *config)
{
	const struct spi_stm32_config *cfg = CONFIG_CFG(config);
	struct spi_stm32_data *data = CONFIG_DATA(config);
	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) {
		return -ENOTSUP;
	}

	clock_control_get_rate(device_get_binding(STM32_CLOCK_CONTROL_NAME),
			       (clock_control_subsys_t) &cfg->pclken, &clock);

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

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

	if (br > ARRAY_SIZE(scaler)) {
		SYS_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->operation & SPI_OP_MODE_SLAVE) {
		LL_SPI_SetMode(spi, LL_SPI_MODE_SLAVE);
	} else {
		LL_SPI_SetMode(spi, LL_SPI_MODE_MASTER);
	}

	if (config->cs) {
		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);
		}
	}

	LL_SPI_SetDataWidth(spi, LL_SPI_DATAWIDTH_8BIT);

#if defined(CONFIG_SOC_SERIES_STM32L4X) || defined(CONFIG_SOC_SERIES_STM32F3X)
	LL_SPI_SetRxFIFOThreshold(spi, LL_SPI_RX_FIFO_TH_QUARTER);
#endif
	LL_SPI_SetStandard(spi, LL_SPI_PROTOCOL_MOTOROLA);

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

	spi_context_cs_configure(&data->ctx);

	SYS_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 spi_config *config)
{
	struct spi_stm32_data *data = CONFIG_DATA(config);

	spi_context_unlock_unconditionally(&data->ctx);

	return 0;
}

static int transceive(struct spi_config *config,
		      const struct spi_buf *tx_bufs, u32_t tx_count,
		      struct spi_buf *rx_bufs, u32_t rx_count,
		      bool asynchronous, struct k_poll_signal *signal)
{
	const struct spi_stm32_config *cfg = CONFIG_CFG(config);
	struct spi_stm32_data *data = CONFIG_DATA(config);
	SPI_TypeDef *spi = cfg->spi;
	int ret;

	if (!tx_count && !rx_count) {
		return 0;
	}

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

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

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

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

#if defined(CONFIG_SOC_SERIES_STM32L4X) || defined(CONFIG_SOC_SERIES_STM32F3X)
	/* Flush RX buffer */
	while (LL_SPI_IsActiveFlag_RXNE(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_SPI_EnableIT_ERR(spi);

	if (rx_bufs) {
		LL_SPI_EnableIT_RXNE(spi);
	}

	LL_SPI_EnableIT_TXE(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);
#endif

	spi_context_release(&data->ctx, ret);

	if (ret) {
		SYS_LOG_ERR("error mask 0x%x", ret);
	}

	return ret ? -EIO : 0;
}

static int spi_stm32_transceive(struct spi_config *config,
				const struct spi_buf *tx_bufs, u32_t tx_count,
				struct spi_buf *rx_bufs, u32_t rx_count)
{
	return transceive(config, tx_bufs, tx_count,
			  rx_bufs, rx_count, false, NULL);
}

#ifdef CONFIG_POLL
static int spi_stm32_transceive_async(struct spi_config *config,
				      const struct spi_buf *tx_bufs,
				      size_t tx_count,
				      struct spi_buf *rx_bufs,
				      size_t rx_count,
				      struct k_poll_signal *async)
{
	return transceive(config, tx_bufs, tx_count,
			  rx_bufs, rx_count, true, async);
}
#endif /* CONFIG_POLL */

static const struct spi_driver_api api_funcs = {
	.transceive = spi_stm32_transceive,
#ifdef CONFIG_POLL
	.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->config_info;

	__ASSERT_NO_MSG(device_get_binding(STM32_CLOCK_CONTROL_NAME));

	clock_control_on(device_get_binding(STM32_CLOCK_CONTROL_NAME),
			       (clock_control_subsys_t) &cfg->pclken);

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

	spi_context_unlock_unconditionally(&data->ctx);

	return 0;
}

#ifdef CONFIG_SPI_1

#ifdef CONFIG_SPI_STM32_INTERRUPT
static void spi_stm32_irq_config_func_1(struct device *port);
#endif

static const struct spi_stm32_config spi_stm32_cfg_1 = {
	.spi = (SPI_TypeDef *) SPI1_BASE,
	.pclken = {
		.enr = LL_APB2_GRP1_PERIPH_SPI1,
		.bus = STM32_CLOCK_BUS_APB2
	},
#ifdef CONFIG_SPI_STM32_INTERRUPT
	.irq_config = spi_stm32_irq_config_func_1,
#endif
};

static struct spi_stm32_data spi_stm32_dev_data_1 = {
	SPI_CONTEXT_INIT_LOCK(spi_stm32_dev_data_1, ctx),
	SPI_CONTEXT_INIT_SYNC(spi_stm32_dev_data_1, ctx),
};

DEVICE_AND_API_INIT(spi_stm32_1, CONFIG_SPI_1_NAME, &spi_stm32_init,
		    &spi_stm32_dev_data_1, &spi_stm32_cfg_1,
		    POST_KERNEL, CONFIG_SPI_INIT_PRIORITY,
		    &api_funcs);

#ifdef CONFIG_SPI_STM32_INTERRUPT
static void spi_stm32_irq_config_func_1(struct device *dev)
{
	IRQ_CONNECT(SPI1_IRQn, CONFIG_SPI_1_IRQ_PRI,
		    spi_stm32_isr, DEVICE_GET(spi_stm32_1), 0);
	irq_enable(SPI1_IRQn);
}
#endif

#endif /* CONFIG_SPI_1 */

#ifdef CONFIG_SPI_2

#ifdef CONFIG_SPI_STM32_INTERRUPT
static void spi_stm32_irq_config_func_2(struct device *port);
#endif

static const struct spi_stm32_config spi_stm32_cfg_2 = {
	.spi = (SPI_TypeDef *) SPI2_BASE,
	.pclken = {
		.enr = LL_APB1_GRP1_PERIPH_SPI2,
		.bus = STM32_CLOCK_BUS_APB1
	},
#ifdef CONFIG_SPI_STM32_INTERRUPT
	.irq_config = spi_stm32_irq_config_func_2,
#endif
};

static struct spi_stm32_data spi_stm32_dev_data_2 = {
	SPI_CONTEXT_INIT_LOCK(spi_stm32_dev_data_2, ctx),
	SPI_CONTEXT_INIT_SYNC(spi_stm32_dev_data_2, ctx),
};

DEVICE_AND_API_INIT(spi_stm32_2, CONFIG_SPI_2_NAME, &spi_stm32_init,
		    &spi_stm32_dev_data_2, &spi_stm32_cfg_2,
		    POST_KERNEL, CONFIG_SPI_INIT_PRIORITY,
		    &api_funcs);

#ifdef CONFIG_SPI_STM32_INTERRUPT
static void spi_stm32_irq_config_func_2(struct device *dev)
{
	IRQ_CONNECT(SPI2_IRQn, CONFIG_SPI_2_IRQ_PRI,
		    spi_stm32_isr, DEVICE_GET(spi_stm32_2), 0);
	irq_enable(SPI2_IRQn);
}
#endif

#endif /* CONFIG_SPI_2 */

#ifdef CONFIG_SPI_3

#ifdef CONFIG_SPI_STM32_INTERRUPT
static void spi_stm32_irq_config_func_3(struct device *port);
#endif

static const  struct spi_stm32_config spi_stm32_cfg_3 = {
	.spi = (SPI_TypeDef *) SPI3_BASE,
	.pclken = {
		.enr = LL_APB1_GRP1_PERIPH_SPI3,
		.bus = STM32_CLOCK_BUS_APB1
	},
#ifdef CONFIG_SPI_STM32_INTERRUPT
	.irq_config = spi_stm32_irq_config_func_3,
#endif
};

static struct spi_stm32_data spi_stm32_dev_data_3 = {
	SPI_CONTEXT_INIT_LOCK(spi_stm32_dev_data_3, ctx),
	SPI_CONTEXT_INIT_SYNC(spi_stm32_dev_data_3, ctx),
};

DEVICE_AND_API_INIT(spi_stm32_3, CONFIG_SPI_3_NAME, &spi_stm32_init,
		    &spi_stm32_dev_data_3, &spi_stm32_cfg_3,
		    POST_KERNEL, CONFIG_SPI_INIT_PRIORITY,
		    &api_funcs);

#ifdef CONFIG_SPI_STM32_INTERRUPT
static void spi_stm32_irq_config_func_3(struct device *dev)
{
	IRQ_CONNECT(SPI3_IRQn, CONFIG_SPI_3_IRQ_PRI,
		    spi_stm32_isr, DEVICE_GET(spi_stm32_3), 0);
	irq_enable(SPI3_IRQn);
}
#endif

#endif /* CONFIG_SPI_3 */