/*
 * Copyright (c) 2018 Intel Corporation.
 *
 * SPDX-License-Identifier: Apache-2.0
 */

#include <errno.h>

#include <stdio.h>
#include <string.h>
#include <kernel.h>
#include <board.h>
#include <device.h>
#include <init.h>
#include <dma.h>

#include "dma_cavs.h"

#define SYS_LOG_DOMAIN "dev/dma_cavs"
#define SYS_LOG_LEVEL CONFIG_SYS_LOG_DMA_LEVEL
#include <logging/sys_log.h>

#define BYTE				(1)
#define WORD				(2)
#define DWORD				(4)

/* CFG_LO */
#define DW_CFG_CLASS(x)			(x << 29)
/* CFG_HI */
#define DW_CFGH_SRC_PER(x)		((x & 0xf) | ((x & 0x30) << 24))
#define DW_CFGH_DST_PER(x)		(((x & 0xf) << 4) | ((x & 0x30) << 26))

/* default initial setup register values */
#define DW_CFG_LOW_DEF			0x0

#define DEV_NAME(dev) ((dev)->config->name)
#define DEV_DATA(dev) ((struct dw_dma_dev_data *const)(dev)->driver_data)
#define DEV_CFG(dev) \
	((const struct dw_dma_dev_cfg *const)(dev)->config->config_info)

/* number of tries to wait for reset */
#define DW_DMA_CFG_TRIES	10000
#define INT_MASK_ALL		0xFF00

static ALWAYS_INLINE void dw_write(u32_t dma_base, u32_t reg, u32_t value)
{
	*((volatile u32_t*)(dma_base + reg)) = value;
}

static ALWAYS_INLINE u32_t dw_read(u32_t dma_base, u32_t reg)
{
	return *((volatile u32_t*)(dma_base + reg));
}

static void dw_dma_isr(void *arg)
{
	struct device *dev = (struct device *)arg;
	const struct dw_dma_dev_cfg *const dev_cfg = DEV_CFG(dev);
	struct dw_dma_dev_data *const dev_data = DEV_DATA(dev);
	struct dma_chan_data *chan_data;

	u32_t status_tfr = 0;
	u32_t status_block = 0;
	u32_t status_err = 0;
	u32_t status_intr;
	u32_t channel;

	status_intr = dw_read(dev_cfg->base, DW_INTR_STATUS);
	if (!status_intr) {
		SYS_LOG_ERR("status_intr = %d", status_intr);
	}

	/* get the source of our IRQ. */
	status_block = dw_read(dev_cfg->base, DW_STATUS_BLOCK);
	status_tfr = dw_read(dev_cfg->base, DW_STATUS_TFR);

	/* TODO: handle errors, just clear them atm */
	status_err = dw_read(dev_cfg->base, DW_STATUS_ERR);
	if (status_err) {
		SYS_LOG_ERR("status_err = %d\n", status_err);
		dw_write(dev_cfg->base, DW_CLEAR_ERR, status_err);
	}

	/* clear interrupts */
	dw_write(dev_cfg->base, DW_CLEAR_BLOCK, status_block);
	dw_write(dev_cfg->base, DW_CLEAR_TFR, status_tfr);

	/* Dispatch ISRs for channels depending upon the bit set */
	while (status_block) {
		channel = find_lsb_set(status_block) - 1;
		status_block &= ~(1 << channel);
		chan_data = &dev_data->chan[channel];

		if (chan_data->dma_blkcallback) {

			/* Ensure the linked list (chan_data->lli) is
			 * freed in the user callback function once
			 * all the blocks are transferred.
			 */
			chan_data->dma_blkcallback(dev, channel, 0);
		}
	}

	while (status_tfr) {
		channel = find_lsb_set(status_tfr) - 1;
		status_tfr &= ~(1 << channel);
		chan_data = &dev_data->chan[channel];
		k_free(chan_data->lli);
		chan_data->lli = NULL;
		if (chan_data->dma_tfrcallback) {
			chan_data->dma_tfrcallback(dev, channel, 0);
		}
	}
}

static int dw_dma_config(struct device *dev, u32_t channel,
			 struct dma_config *cfg)
{
	struct dw_dma_dev_data *const dev_data = DEV_DATA(dev);
	struct dma_chan_data *chan_data;
	struct dma_block_config *cfg_blocks;
	u32_t cnt;
	u32_t m_size;
	u32_t tr_width;

	struct dw_lli2 *lli_desc;
	struct dw_lli2 *lli_desc_tail;

	if (channel >= DW_MAX_CHAN) {
		return -EINVAL;
	}

	__ASSERT_NO_MSG(cfg->source_data_size == cfg->dest_data_size);
	__ASSERT_NO_MSG(cfg->source_burst_length == cfg->dest_burst_length);

	if (cfg->source_data_size != BYTE && cfg->source_data_size != WORD &&
	    cfg->source_data_size != DWORD) {
		SYS_LOG_ERR("Invalid 'source_data_size' value");
		return -EINVAL;
	}

	chan_data = &dev_data->chan[channel];

	/* default channel config */
	chan_data->direction = cfg->channel_direction;
	chan_data->cfg_lo = DW_CFG_LOW_DEF;
	chan_data->cfg_hi = DW_CFG_LOW_DEF;

	/* data_size = (2 ^ tr_width) */
	tr_width = find_msb_set(cfg->source_data_size) - 1;
	SYS_LOG_DBG("tr_width=%d", tr_width);

	/* burst_size = (2 ^ msize) */
	m_size = find_msb_set(cfg->source_burst_length) - 1;
	SYS_LOG_DBG("m_size=%d", m_size);

	cfg_blocks = cfg->head_block;

	/* Allocate space for the linked list */
	chan_data->lli = (struct dw_lli2 *)k_malloc(sizeof(struct dw_lli2)
							* (cfg->block_count));
	if (chan_data->lli == NULL) {
		SYS_LOG_ERR("not enough memory\n");
		return -ENOMEM;
	}

	(void)memset(chan_data->lli, 0,
		     (sizeof(struct dw_lli2) * cfg->block_count));
	lli_desc = chan_data->lli;
	lli_desc_tail = lli_desc + cfg->block_count - 1;

	/* initialize descriptors */
	cnt = cfg->block_count;

	do {
		lli_desc->ctrl_lo |= DW_CTLL_SRC_WIDTH(tr_width);
		lli_desc->ctrl_lo |= DW_CTLL_DST_WIDTH(tr_width);
		lli_desc->ctrl_lo |= DW_CTLL_SRC_MSIZE(m_size);
		lli_desc->ctrl_lo |= DW_CTLL_DST_MSIZE(m_size);

		/* enable interrupt */
		lli_desc->ctrl_lo |= DW_CTLL_INT_EN;

		switch (cfg->channel_direction) {

		case MEMORY_TO_MEMORY:
			lli_desc->ctrl_lo |= DW_CTLL_FC_M2M;
			lli_desc->ctrl_lo |= DW_CTLL_SRC_INC | DW_CTLL_DST_INC;
			break;

		case MEMORY_TO_PERIPHERAL:
			lli_desc->ctrl_lo |= DW_CTLL_FC_M2P;
			lli_desc->ctrl_lo |= DW_CTLL_SRC_INC | DW_CTLL_DST_FIX;

			/* Assign a hardware handshaking interface (0-15) to the
			 * destination of channel
			 */
			chan_data->cfg_hi |=
				DW_CFGH_DST_PER(cfg->dma_slot);
			break;

		case PERIPHERAL_TO_MEMORY:
			lli_desc->ctrl_lo |= DW_CTLL_FC_P2M;
			lli_desc->ctrl_lo |= DW_CTLL_SRC_FIX | DW_CTLL_DST_INC;

			/* Assign a hardware handshaking interface (0-15) to the
			 * source of channel
			 */
			chan_data->cfg_hi |=
				DW_CFGH_SRC_PER(cfg->dma_slot);
			break;

		default:
			SYS_LOG_ERR("channel_direction %d is not supported",
				    cfg->channel_direction);
			return -EINVAL;
		}

		lli_desc->sar = cfg_blocks->source_address;
		lli_desc->dar = cfg_blocks->dest_address;

		/* Block size */
		lli_desc->ctrl_hi = DW_CFG_CLASS(
				dev_data->channel_data->chan[channel].class) |
				cfg_blocks->block_size;

		/* set next descriptor in list */
		lli_desc->llp = (u32_t)(lli_desc + 1);
		lli_desc->ctrl_lo |= DW_CTLL_LLP_S_EN | DW_CTLL_LLP_D_EN;

		/* next descriptor */
		lli_desc++;
		cfg_blocks = cfg_blocks->next_block;
		cnt--;
	} while (cfg_blocks && cnt);

	/* check if application requests circular list */
	if (cfg_blocks) {
		/*
		 * if the last block was pointing to another block, then
		 * it means the application is requesting a circular list
		 */
		lli_desc_tail->llp = (u32_t)chan_data->lli;
	} else {
		lli_desc_tail->llp = 0x0;
		lli_desc_tail->ctrl_lo &=
			~(DW_CTLL_LLP_S_EN | DW_CTLL_LLP_D_EN);
	}

#ifdef CONFIG_DCACHE_WRITEBACK
	/* Flush the cache so that the descriptors are written to the memory.
	 * If this is not done, DMA engine will read the old stale data at
	 * that location and hence the DMA operation will not succeed.
	 */
	dcache_writeback_region(chan_data->lli,
			sizeof(struct dw_lli2) * cfg->block_count);
#endif

	/* Configure a callback appropriately depending on whether the
	 * interrupt is requested at the end of transaction completion or
	 * at the end of each block.
	 */
	if (cfg->complete_callback_en) {
		chan_data->dma_blkcallback = cfg->dma_callback;
	} else {
		chan_data->dma_tfrcallback = cfg->dma_callback;
	}

	return 0;
}

static int dw_dma_transfer_start(struct device *dev, u32_t channel)
{
	const struct dw_dma_dev_cfg *const dev_cfg = DEV_CFG(dev);
	struct dw_dma_dev_data *const dev_data = DEV_DATA(dev);
	struct dma_chan_data *chan_data;

	if (channel >= DW_MAX_CHAN) {
		return -EINVAL;
	}

	chan_data = &dev_data->chan[channel];

	if (chan_data->dma_tfrcallback) {
		dw_write(dev_cfg->base, DW_MASK_TFR, INT_UNMASK(channel));
	}

	if (chan_data->dma_blkcallback) {
		dw_write(dev_cfg->base, DW_MASK_BLOCK, INT_UNMASK(channel));
	}

	dw_write(dev_cfg->base, DW_MASK_ERR, INT_UNMASK(channel));

	/* write interrupt clear registers for the channel
	 * ClearTfr, ClearBlock, ClearSrcTran, ClearDstTran, ClearErr
	 */
	dw_write(dev_cfg->base, DW_CLEAR_TFR, 0x1 << channel);
	dw_write(dev_cfg->base, DW_CLEAR_BLOCK, 0x1 << channel);
	dw_write(dev_cfg->base, DW_CLEAR_SRC_TRAN, 0x1 << channel);
	dw_write(dev_cfg->base, DW_CLEAR_DST_TRAN, 0x1 << channel);
	dw_write(dev_cfg->base, DW_CLEAR_ERR, 0x1 << channel);

	if (chan_data->lli->llp) {
		/* LLP mode - only write LLP pointer */
		dw_write(dev_cfg->base, DW_LLP(channel), (u32_t)chan_data->lli);
	} else {
		/* single transfer, must set zero */
		dw_write(dev_cfg->base, DW_LLP(channel), 0);
	}

	/* channel needs started from scratch, so write SARn, DARn */
	dw_write(dev_cfg->base, DW_SAR(channel), chan_data->lli->sar);
	dw_write(dev_cfg->base, DW_DAR(channel), chan_data->lli->dar);

	/* program CTLn */
	dw_write(dev_cfg->base, DW_CTRL_LOW(channel), chan_data->lli->ctrl_lo);
	dw_write(dev_cfg->base, DW_CTRL_HIGH(channel), chan_data->lli->ctrl_hi);

	/* write channel config */
	dw_write(dev_cfg->base, DW_CFG_LOW(channel), chan_data->cfg_lo);
	dw_write(dev_cfg->base, DW_CFG_HIGH(channel), chan_data->cfg_hi);

	/* enable the channel */
	dw_write(dev_cfg->base, DW_DMA_CHAN_EN, CHAN_ENABLE(channel));

	return 0;
}

static int dw_dma_transfer_stop(struct device *dev, u32_t channel)
{
	const struct dw_dma_dev_cfg *const dev_cfg = DEV_CFG(dev);

	if (channel >= DW_MAX_CHAN) {
		return -EINVAL;
	}

	/* mask block, transfer and error interrupts for channel */
	dw_write(dev_cfg->base, DW_MASK_TFR, INT_MASK(channel));
	dw_write(dev_cfg->base, DW_MASK_BLOCK, INT_MASK(channel));
	dw_write(dev_cfg->base, DW_MASK_ERR, INT_MASK(channel));

	/* disable the channel */
	dw_write(dev_cfg->base, DW_DMA_CHAN_EN, CHAN_DISABLE(channel));
	return 0;
}

static void dw_dma_setup(struct device *dev)
{
	const struct dw_dma_dev_cfg *const dev_cfg = DEV_CFG(dev);
	struct dw_dma_dev_data *const dev_data = DEV_DATA(dev);
	struct dw_drv_plat_data *dp = dev_data->channel_data;
	int i;

	/* we cannot config DMAC if DMAC has been already enabled by host */
	if (dw_read(dev_cfg->base, DW_DMA_CFG) != 0) {
		dw_write(dev_cfg->base, DW_DMA_CFG, 0x0);
	}

	/* now check that it's 0 */
	for (i = DW_DMA_CFG_TRIES; i > 0; i--) {
		if (dw_read(dev_cfg->base, DW_DMA_CFG) == 0) {
			goto found;
		}
	}
	SYS_LOG_ERR("DW_DMA_CFG is non-zero\n");
	return;

found:
	for (i = 0; i <  DW_MAX_CHAN; i++) {
		dw_read(dev_cfg->base, DW_DMA_CHAN_EN);
	}

	/* enable the DMA controller */
	dw_write(dev_cfg->base, DW_DMA_CFG, 1);

	/* mask all interrupts for all 8 channels */
	dw_write(dev_cfg->base, DW_MASK_TFR, INT_MASK_ALL);
	dw_write(dev_cfg->base, DW_MASK_BLOCK, INT_MASK_ALL);
	dw_write(dev_cfg->base, DW_MASK_SRC_TRAN, INT_MASK_ALL);
	dw_write(dev_cfg->base, DW_MASK_DST_TRAN, INT_MASK_ALL);
	dw_write(dev_cfg->base, DW_MASK_ERR, INT_MASK_ALL);

	/* set channel priorities */
	for (i = 0; i <  DW_MAX_CHAN; i++) {
		dw_write(dev_cfg->base, DW_CTRL_HIGH(i),
		DW_CFG_CLASS(dp->chan[i].class));
	}
}

static int dw_dma0_initialize(struct device *dev)
{
	const struct dw_dma_dev_cfg *const dev_cfg = DEV_CFG(dev);

	/* Disable all channels and Channel interrupts */
	dw_dma_setup(dev);

	/* Configure interrupts */
	dev_cfg->irq_config();

	/* Enable module's IRQ */
	irq_enable(dev_cfg->irq_id);

	SYS_LOG_INF("Device %s initialized", DEV_NAME(dev));

	return 0;
}

static const struct dma_driver_api dw_dma_driver_api = {
	.config = dw_dma_config,
	.start = dw_dma_transfer_start,
	.stop = dw_dma_transfer_stop,
};

/* DMA0 */

static struct device DEVICE_NAME_GET(dw_dma0);

static void dw_dma0_irq_config(void)
{
	IRQ_CONNECT(DW_DMA0_IRQ, CONFIG_DMA_0_IRQ_PRI, dw_dma_isr,
		    DEVICE_GET(dw_dma0), 0);
}

static struct dw_drv_plat_data dmac0 = {
	.chan[0] = {
		.class  = 6,
		.weight = 0,
	},
	.chan[1] = {
		.class  = 6,
		.weight = 0,
	},
	.chan[2] = {
		.class  = 6,
		.weight = 0,
	},
	.chan[3] = {
		.class  = 6,
		.weight = 0,
	},
	.chan[4] = {
		.class  = 6,
		.weight = 0,
	},
	.chan[5] = {
		.class  = 6,
		.weight = 0,
	},
	.chan[6] = {
		.class  = 6,
		.weight = 0,
	},
	.chan[7] = {
		.class  = 6,
		.weight = 0,
	},
};

static const struct dw_dma_dev_cfg dw_dma0_config = {
	.base = DW_DMA0_BASE_ADDR,
	.irq_config = dw_dma0_irq_config,
	.irq_id = DW_DMA0_IRQ,
};

static struct dw_dma_dev_data dw_dma0_data = {
	.channel_data = &dmac0,
};

DEVICE_AND_API_INIT(dw_dma0, CONFIG_DMA_0_NAME, &dw_dma0_initialize,
		    &dw_dma0_data, &dw_dma0_config, POST_KERNEL,
		    CONFIG_KERNEL_INIT_PRIORITY_DEVICE, &dw_dma_driver_api);