/*
 * Copyright (c) 2008-2014, The Linux foundation. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License rev 2 and
 * only rev 2 as published by the free Software foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or fITNESS fOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/spi/spi.h>
#include <linux/dmaengine.h>
#include <linux/dma-mapping.h>

#define QUP_CONFIG			0x0000
#define QUP_STATE			0x0004
#define QUP_IO_M_MODES			0x0008
#define QUP_SW_RESET			0x000c
#define QUP_OPERATIONAL			0x0018
#define QUP_ERROR_FLAGS			0x001c
#define QUP_ERROR_FLAGS_EN		0x0020
#define QUP_OPERATIONAL_MASK		0x0028
#define QUP_HW_VERSION			0x0030
#define QUP_MX_OUTPUT_CNT		0x0100
#define QUP_OUTPUT_FIFO			0x0110
#define QUP_MX_WRITE_CNT		0x0150
#define QUP_MX_INPUT_CNT		0x0200
#define QUP_MX_READ_CNT			0x0208
#define QUP_INPUT_FIFO			0x0218

#define SPI_CONFIG			0x0300
#define SPI_IO_CONTROL			0x0304
#define SPI_ERROR_FLAGS			0x0308
#define SPI_ERROR_FLAGS_EN		0x030c

/* QUP_CONFIG fields */
#define QUP_CONFIG_SPI_MODE		(1 << 8)
#define QUP_CONFIG_CLOCK_AUTO_GATE	BIT(13)
#define QUP_CONFIG_NO_INPUT		BIT(7)
#define QUP_CONFIG_NO_OUTPUT		BIT(6)
#define QUP_CONFIG_N			0x001f

/* QUP_STATE fields */
#define QUP_STATE_VALID			BIT(2)
#define QUP_STATE_RESET			0
#define QUP_STATE_RUN			1
#define QUP_STATE_PAUSE			3
#define QUP_STATE_MASK			3
#define QUP_STATE_CLEAR			2

#define QUP_HW_VERSION_2_1_1		0x20010001

/* QUP_IO_M_MODES fields */
#define QUP_IO_M_PACK_EN		BIT(15)
#define QUP_IO_M_UNPACK_EN		BIT(14)
#define QUP_IO_M_INPUT_MODE_MASK_SHIFT	12
#define QUP_IO_M_OUTPUT_MODE_MASK_SHIFT	10
#define QUP_IO_M_INPUT_MODE_MASK	(3 << QUP_IO_M_INPUT_MODE_MASK_SHIFT)
#define QUP_IO_M_OUTPUT_MODE_MASK	(3 << QUP_IO_M_OUTPUT_MODE_MASK_SHIFT)

#define QUP_IO_M_OUTPUT_BLOCK_SIZE(x)	(((x) & (0x03 << 0)) >> 0)
#define QUP_IO_M_OUTPUT_FIFO_SIZE(x)	(((x) & (0x07 << 2)) >> 2)
#define QUP_IO_M_INPUT_BLOCK_SIZE(x)	(((x) & (0x03 << 5)) >> 5)
#define QUP_IO_M_INPUT_FIFO_SIZE(x)	(((x) & (0x07 << 7)) >> 7)

#define QUP_IO_M_MODE_FIFO		0
#define QUP_IO_M_MODE_BLOCK		1
#define QUP_IO_M_MODE_DMOV		2
#define QUP_IO_M_MODE_BAM		3

/* QUP_OPERATIONAL fields */
#define QUP_OP_MAX_INPUT_DONE_FLAG	BIT(11)
#define QUP_OP_MAX_OUTPUT_DONE_FLAG	BIT(10)
#define QUP_OP_IN_SERVICE_FLAG		BIT(9)
#define QUP_OP_OUT_SERVICE_FLAG		BIT(8)
#define QUP_OP_IN_FIFO_FULL		BIT(7)
#define QUP_OP_OUT_FIFO_FULL		BIT(6)
#define QUP_OP_IN_FIFO_NOT_EMPTY	BIT(5)
#define QUP_OP_OUT_FIFO_NOT_EMPTY	BIT(4)

/* QUP_ERROR_FLAGS and QUP_ERROR_FLAGS_EN fields */
#define QUP_ERROR_OUTPUT_OVER_RUN	BIT(5)
#define QUP_ERROR_INPUT_UNDER_RUN	BIT(4)
#define QUP_ERROR_OUTPUT_UNDER_RUN	BIT(3)
#define QUP_ERROR_INPUT_OVER_RUN	BIT(2)

/* SPI_CONFIG fields */
#define SPI_CONFIG_HS_MODE		BIT(10)
#define SPI_CONFIG_INPUT_FIRST		BIT(9)
#define SPI_CONFIG_LOOPBACK		BIT(8)

/* SPI_IO_CONTROL fields */
#define SPI_IO_C_FORCE_CS		BIT(11)
#define SPI_IO_C_CLK_IDLE_HIGH		BIT(10)
#define SPI_IO_C_MX_CS_MODE		BIT(8)
#define SPI_IO_C_CS_N_POLARITY_0	BIT(4)
#define SPI_IO_C_CS_SELECT(x)		(((x) & 3) << 2)
#define SPI_IO_C_CS_SELECT_MASK		0x000c
#define SPI_IO_C_TRISTATE_CS		BIT(1)
#define SPI_IO_C_NO_TRI_STATE		BIT(0)

/* SPI_ERROR_FLAGS and SPI_ERROR_FLAGS_EN fields */
#define SPI_ERROR_CLK_OVER_RUN		BIT(1)
#define SPI_ERROR_CLK_UNDER_RUN		BIT(0)

#define SPI_NUM_CHIPSELECTS		4

#define SPI_MAX_DMA_XFER		(SZ_64K - 64)

/* high speed mode is when bus rate is greater then 26MHz */
#define SPI_HS_MIN_RATE			26000000
#define SPI_MAX_RATE			50000000

#define SPI_DELAY_THRESHOLD		1
#define SPI_DELAY_RETRY			10

struct spi_qup {
	void __iomem		*base;
	struct device		*dev;
	struct clk		*cclk;	/* core clock */
	struct clk		*iclk;	/* interface clock */
	int			irq;
	spinlock_t		lock;

	int			in_fifo_sz;
	int			out_fifo_sz;
	int			in_blk_sz;
	int			out_blk_sz;

	struct spi_transfer	*xfer;
	struct completion	done;
	int			error;
	int			w_size;	/* bytes per SPI word */
	int			n_words;
	int			tx_bytes;
	int			rx_bytes;
	int			qup_v1;

	int			mode;
	struct dma_slave_config	rx_conf;
	struct dma_slave_config	tx_conf;
};

static inline bool spi_qup_is_dma_xfer(int mode)
{
	if (mode == QUP_IO_M_MODE_DMOV || mode == QUP_IO_M_MODE_BAM)
		return true;

	return false;
}

static inline bool spi_qup_is_valid_state(struct spi_qup *controller)
{
	u32 opstate = readl_relaxed(controller->base + QUP_STATE);

	return opstate & QUP_STATE_VALID;
}

static int spi_qup_set_state(struct spi_qup *controller, u32 state)
{
	unsigned long loop;
	u32 cur_state;

	loop = 0;
	while (!spi_qup_is_valid_state(controller)) {

		usleep_range(SPI_DELAY_THRESHOLD, SPI_DELAY_THRESHOLD * 2);

		if (++loop > SPI_DELAY_RETRY)
			return -EIO;
	}

	if (loop)
		dev_dbg(controller->dev, "invalid state for %ld,us %d\n",
			loop, state);

	cur_state = readl_relaxed(controller->base + QUP_STATE);
	/*
	 * Per spec: for PAUSE_STATE to RESET_STATE, two writes
	 * of (b10) are required
	 */
	if (((cur_state & QUP_STATE_MASK) == QUP_STATE_PAUSE) &&
	    (state == QUP_STATE_RESET)) {
		writel_relaxed(QUP_STATE_CLEAR, controller->base + QUP_STATE);
		writel_relaxed(QUP_STATE_CLEAR, controller->base + QUP_STATE);
	} else {
		cur_state &= ~QUP_STATE_MASK;
		cur_state |= state;
		writel_relaxed(cur_state, controller->base + QUP_STATE);
	}

	loop = 0;
	while (!spi_qup_is_valid_state(controller)) {

		usleep_range(SPI_DELAY_THRESHOLD, SPI_DELAY_THRESHOLD * 2);

		if (++loop > SPI_DELAY_RETRY)
			return -EIO;
	}

	return 0;
}

static void spi_qup_fifo_read(struct spi_qup *controller,
			    struct spi_transfer *xfer)
{
	u8 *rx_buf = xfer->rx_buf;
	u32 word, state;
	int idx, shift, w_size;

	w_size = controller->w_size;

	while (controller->rx_bytes < xfer->len) {

		state = readl_relaxed(controller->base + QUP_OPERATIONAL);
		if (0 == (state & QUP_OP_IN_FIFO_NOT_EMPTY))
			break;

		word = readl_relaxed(controller->base + QUP_INPUT_FIFO);

		if (!rx_buf) {
			controller->rx_bytes += w_size;
			continue;
		}

		for (idx = 0; idx < w_size; idx++, controller->rx_bytes++) {
			/*
			 * The data format depends on bytes per SPI word:
			 *  4 bytes: 0x12345678
			 *  2 bytes: 0x00001234
			 *  1 byte : 0x00000012
			 */
			shift = BITS_PER_BYTE;
			shift *= (w_size - idx - 1);
			rx_buf[controller->rx_bytes] = word >> shift;
		}
	}
}

static void spi_qup_fifo_write(struct spi_qup *controller,
			    struct spi_transfer *xfer)
{
	const u8 *tx_buf = xfer->tx_buf;
	u32 word, state, data;
	int idx, w_size;

	w_size = controller->w_size;

	while (controller->tx_bytes < xfer->len) {

		state = readl_relaxed(controller->base + QUP_OPERATIONAL);
		if (state & QUP_OP_OUT_FIFO_FULL)
			break;

		word = 0;
		for (idx = 0; idx < w_size; idx++, controller->tx_bytes++) {

			if (!tx_buf) {
				controller->tx_bytes += w_size;
				break;
			}

			data = tx_buf[controller->tx_bytes];
			word |= data << (BITS_PER_BYTE * (3 - idx));
		}

		writel_relaxed(word, controller->base + QUP_OUTPUT_FIFO);
	}
}

static void spi_qup_dma_done(void *data)
{
	struct spi_qup *qup = data;

	complete(&qup->done);
}

static int spi_qup_prep_sg(struct spi_master *master, struct spi_transfer *xfer,
			   enum dma_transfer_direction dir,
			   dma_async_tx_callback callback)
{
	struct spi_qup *qup = spi_master_get_devdata(master);
	unsigned long flags = DMA_PREP_INTERRUPT | DMA_PREP_FENCE;
	struct dma_async_tx_descriptor *desc;
	struct scatterlist *sgl;
	struct dma_chan *chan;
	dma_cookie_t cookie;
	unsigned int nents;

	if (dir == DMA_MEM_TO_DEV) {
		chan = master->dma_tx;
		nents = xfer->tx_sg.nents;
		sgl = xfer->tx_sg.sgl;
	} else {
		chan = master->dma_rx;
		nents = xfer->rx_sg.nents;
		sgl = xfer->rx_sg.sgl;
	}

	desc = dmaengine_prep_slave_sg(chan, sgl, nents, dir, flags);
	if (!desc)
		return -EINVAL;

	desc->callback = callback;
	desc->callback_param = qup;

	cookie = dmaengine_submit(desc);

	return dma_submit_error(cookie);
}

static void spi_qup_dma_terminate(struct spi_master *master,
				  struct spi_transfer *xfer)
{
	if (xfer->tx_buf)
		dmaengine_terminate_all(master->dma_tx);
	if (xfer->rx_buf)
		dmaengine_terminate_all(master->dma_rx);
}

static int spi_qup_do_dma(struct spi_master *master, struct spi_transfer *xfer,
			  unsigned long timeout)
{
	struct spi_qup *qup = spi_master_get_devdata(master);
	dma_async_tx_callback rx_done = NULL, tx_done = NULL;
	int ret;

	if (xfer->rx_buf)
		rx_done = spi_qup_dma_done;
	else if (xfer->tx_buf)
		tx_done = spi_qup_dma_done;

	if (xfer->rx_buf) {
		ret = spi_qup_prep_sg(master, xfer, DMA_DEV_TO_MEM, rx_done);
		if (ret)
			return ret;

		dma_async_issue_pending(master->dma_rx);
	}

	if (xfer->tx_buf) {
		ret = spi_qup_prep_sg(master, xfer, DMA_MEM_TO_DEV, tx_done);
		if (ret)
			return ret;

		dma_async_issue_pending(master->dma_tx);
	}

	if (!wait_for_completion_timeout(&qup->done, timeout))
		return -ETIMEDOUT;

	return 0;
}

static int spi_qup_do_pio(struct spi_master *master, struct spi_transfer *xfer,
			  unsigned long timeout)
{
	struct spi_qup *qup = spi_master_get_devdata(master);
	int ret;

	ret = spi_qup_set_state(qup, QUP_STATE_RUN);
	if (ret) {
		dev_warn(qup->dev, "cannot set RUN state\n");
		return ret;
	}

	ret = spi_qup_set_state(qup, QUP_STATE_PAUSE);
	if (ret) {
		dev_warn(qup->dev, "cannot set PAUSE state\n");
		return ret;
	}

	spi_qup_fifo_write(qup, xfer);

	if (!wait_for_completion_timeout(&qup->done, timeout))
		return -ETIMEDOUT;

	return 0;
}

static irqreturn_t spi_qup_qup_irq(int irq, void *dev_id)
{
	struct spi_qup *controller = dev_id;
	struct spi_transfer *xfer;
	u32 opflags, qup_err, spi_err;
	unsigned long flags;
	int error = 0;

	spin_lock_irqsave(&controller->lock, flags);
	xfer = controller->xfer;
	controller->xfer = NULL;
	spin_unlock_irqrestore(&controller->lock, flags);

	qup_err = readl_relaxed(controller->base + QUP_ERROR_FLAGS);
	spi_err = readl_relaxed(controller->base + SPI_ERROR_FLAGS);
	opflags = readl_relaxed(controller->base + QUP_OPERATIONAL);

	writel_relaxed(qup_err, controller->base + QUP_ERROR_FLAGS);
	writel_relaxed(spi_err, controller->base + SPI_ERROR_FLAGS);
	writel_relaxed(opflags, controller->base + QUP_OPERATIONAL);

	if (!xfer) {
		dev_err_ratelimited(controller->dev, "unexpected irq %08x %08x %08x\n",
				    qup_err, spi_err, opflags);
		return IRQ_HANDLED;
	}

	if (qup_err) {
		if (qup_err & QUP_ERROR_OUTPUT_OVER_RUN)
			dev_warn(controller->dev, "OUTPUT_OVER_RUN\n");
		if (qup_err & QUP_ERROR_INPUT_UNDER_RUN)
			dev_warn(controller->dev, "INPUT_UNDER_RUN\n");
		if (qup_err & QUP_ERROR_OUTPUT_UNDER_RUN)
			dev_warn(controller->dev, "OUTPUT_UNDER_RUN\n");
		if (qup_err & QUP_ERROR_INPUT_OVER_RUN)
			dev_warn(controller->dev, "INPUT_OVER_RUN\n");

		error = -EIO;
	}

	if (spi_err) {
		if (spi_err & SPI_ERROR_CLK_OVER_RUN)
			dev_warn(controller->dev, "CLK_OVER_RUN\n");
		if (spi_err & SPI_ERROR_CLK_UNDER_RUN)
			dev_warn(controller->dev, "CLK_UNDER_RUN\n");

		error = -EIO;
	}

	if (!spi_qup_is_dma_xfer(controller->mode)) {
		if (opflags & QUP_OP_IN_SERVICE_FLAG)
			spi_qup_fifo_read(controller, xfer);

		if (opflags & QUP_OP_OUT_SERVICE_FLAG)
			spi_qup_fifo_write(controller, xfer);
	}

	spin_lock_irqsave(&controller->lock, flags);
	controller->error = error;
	controller->xfer = xfer;
	spin_unlock_irqrestore(&controller->lock, flags);

	if (controller->rx_bytes == xfer->len || error)
		complete(&controller->done);

	return IRQ_HANDLED;
}

/* set clock freq ... bits per word */
static int spi_qup_io_config(struct spi_device *spi, struct spi_transfer *xfer)
{
	struct spi_qup *controller = spi_master_get_devdata(spi->master);
	u32 config, iomode, control;
	int ret, n_words;

	if (spi->mode & SPI_LOOP && xfer->len > controller->in_fifo_sz) {
		dev_err(controller->dev, "too big size for loopback %d > %d\n",
			xfer->len, controller->in_fifo_sz);
		return -EIO;
	}

	ret = clk_set_rate(controller->cclk, xfer->speed_hz);
	if (ret) {
		dev_err(controller->dev, "fail to set frequency %d",
			xfer->speed_hz);
		return -EIO;
	}

	if (spi_qup_set_state(controller, QUP_STATE_RESET)) {
		dev_err(controller->dev, "cannot set RESET state\n");
		return -EIO;
	}

	controller->w_size = DIV_ROUND_UP(xfer->bits_per_word, 8);
	controller->n_words = xfer->len / controller->w_size;
	n_words = controller->n_words;

	if (n_words <= (controller->in_fifo_sz / sizeof(u32))) {

		controller->mode = QUP_IO_M_MODE_FIFO;

		writel_relaxed(n_words, controller->base + QUP_MX_READ_CNT);
		writel_relaxed(n_words, controller->base + QUP_MX_WRITE_CNT);
		/* must be zero for FIFO */
		writel_relaxed(0, controller->base + QUP_MX_INPUT_CNT);
		writel_relaxed(0, controller->base + QUP_MX_OUTPUT_CNT);
	} else if (spi->master->can_dma &&
		   spi->master->can_dma(spi->master, spi, xfer) &&
		   spi->master->cur_msg_mapped) {

		controller->mode = QUP_IO_M_MODE_BAM;

		writel_relaxed(n_words, controller->base + QUP_MX_INPUT_CNT);
		writel_relaxed(n_words, controller->base + QUP_MX_OUTPUT_CNT);
		/* must be zero for BLOCK and BAM */
		writel_relaxed(0, controller->base + QUP_MX_READ_CNT);
		writel_relaxed(0, controller->base + QUP_MX_WRITE_CNT);

		if (!controller->qup_v1) {
			void __iomem *input_cnt;

			input_cnt = controller->base + QUP_MX_INPUT_CNT;
			/*
			 * for DMA transfers, both QUP_MX_INPUT_CNT and
			 * QUP_MX_OUTPUT_CNT must be zero to all cases but one.
			 * That case is a non-balanced transfer when there is
			 * only a rx_buf.
			 */
			if (xfer->tx_buf)
				writel_relaxed(0, input_cnt);
			else
				writel_relaxed(n_words, input_cnt);

			writel_relaxed(0, controller->base + QUP_MX_OUTPUT_CNT);
		}
	} else {

		controller->mode = QUP_IO_M_MODE_BLOCK;

		writel_relaxed(n_words, controller->base + QUP_MX_INPUT_CNT);
		writel_relaxed(n_words, controller->base + QUP_MX_OUTPUT_CNT);
		/* must be zero for BLOCK and BAM */
		writel_relaxed(0, controller->base + QUP_MX_READ_CNT);
		writel_relaxed(0, controller->base + QUP_MX_WRITE_CNT);
	}

	iomode = readl_relaxed(controller->base + QUP_IO_M_MODES);
	/* Set input and output transfer mode */
	iomode &= ~(QUP_IO_M_INPUT_MODE_MASK | QUP_IO_M_OUTPUT_MODE_MASK);

	if (!spi_qup_is_dma_xfer(controller->mode))
		iomode &= ~(QUP_IO_M_PACK_EN | QUP_IO_M_UNPACK_EN);
	else
		iomode |= QUP_IO_M_PACK_EN | QUP_IO_M_UNPACK_EN;

	iomode |= (controller->mode << QUP_IO_M_OUTPUT_MODE_MASK_SHIFT);
	iomode |= (controller->mode << QUP_IO_M_INPUT_MODE_MASK_SHIFT);

	writel_relaxed(iomode, controller->base + QUP_IO_M_MODES);

	control = readl_relaxed(controller->base + SPI_IO_CONTROL);

	if (spi->mode & SPI_CPOL)
		control |= SPI_IO_C_CLK_IDLE_HIGH;
	else
		control &= ~SPI_IO_C_CLK_IDLE_HIGH;

	writel_relaxed(control, controller->base + SPI_IO_CONTROL);

	config = readl_relaxed(controller->base + SPI_CONFIG);

	if (spi->mode & SPI_LOOP)
		config |= SPI_CONFIG_LOOPBACK;
	else
		config &= ~SPI_CONFIG_LOOPBACK;

	if (spi->mode & SPI_CPHA)
		config &= ~SPI_CONFIG_INPUT_FIRST;
	else
		config |= SPI_CONFIG_INPUT_FIRST;

	/*
	 * HS_MODE improves signal stability for spi-clk high rates,
	 * but is invalid in loop back mode.
	 */
	if ((xfer->speed_hz >= SPI_HS_MIN_RATE) && !(spi->mode & SPI_LOOP))
		config |= SPI_CONFIG_HS_MODE;
	else
		config &= ~SPI_CONFIG_HS_MODE;

	writel_relaxed(config, controller->base + SPI_CONFIG);

	config = readl_relaxed(controller->base + QUP_CONFIG);
	config &= ~(QUP_CONFIG_NO_INPUT | QUP_CONFIG_NO_OUTPUT | QUP_CONFIG_N);
	config |= xfer->bits_per_word - 1;
	config |= QUP_CONFIG_SPI_MODE;

	if (spi_qup_is_dma_xfer(controller->mode)) {
		if (!xfer->tx_buf)
			config |= QUP_CONFIG_NO_OUTPUT;
		if (!xfer->rx_buf)
			config |= QUP_CONFIG_NO_INPUT;
	}

	writel_relaxed(config, controller->base + QUP_CONFIG);

	/* only write to OPERATIONAL_MASK when register is present */
	if (!controller->qup_v1) {
		u32 mask = 0;

		/*
		 * mask INPUT and OUTPUT service flags to prevent IRQs on FIFO
		 * status change in BAM mode
		 */

		if (spi_qup_is_dma_xfer(controller->mode))
			mask = QUP_OP_IN_SERVICE_FLAG | QUP_OP_OUT_SERVICE_FLAG;

		writel_relaxed(mask, controller->base + QUP_OPERATIONAL_MASK);
	}

	return 0;
}

static int spi_qup_transfer_one(struct spi_master *master,
			      struct spi_device *spi,
			      struct spi_transfer *xfer)
{
	struct spi_qup *controller = spi_master_get_devdata(master);
	unsigned long timeout, flags;
	int ret = -EIO;

	ret = spi_qup_io_config(spi, xfer);
	if (ret)
		return ret;

	timeout = DIV_ROUND_UP(xfer->speed_hz, MSEC_PER_SEC);
	timeout = DIV_ROUND_UP(xfer->len * 8, timeout);
	timeout = 100 * msecs_to_jiffies(timeout);

	reinit_completion(&controller->done);

	spin_lock_irqsave(&controller->lock, flags);
	controller->xfer     = xfer;
	controller->error    = 0;
	controller->rx_bytes = 0;
	controller->tx_bytes = 0;
	spin_unlock_irqrestore(&controller->lock, flags);

	if (spi_qup_is_dma_xfer(controller->mode))
		ret = spi_qup_do_dma(master, xfer, timeout);
	else
		ret = spi_qup_do_pio(master, xfer, timeout);

	if (ret)
		goto exit;

exit:
	spi_qup_set_state(controller, QUP_STATE_RESET);
	spin_lock_irqsave(&controller->lock, flags);
	controller->xfer = NULL;
	if (!ret)
		ret = controller->error;
	spin_unlock_irqrestore(&controller->lock, flags);

	if (ret && spi_qup_is_dma_xfer(controller->mode))
		spi_qup_dma_terminate(master, xfer);

	return ret;
}

static bool spi_qup_can_dma(struct spi_master *master, struct spi_device *spi,
			    struct spi_transfer *xfer)
{
	struct spi_qup *qup = spi_master_get_devdata(master);
	size_t dma_align = dma_get_cache_alignment();
	int n_words;

	if (xfer->rx_buf) {
		if (!IS_ALIGNED((size_t)xfer->rx_buf, dma_align) ||
		    IS_ERR_OR_NULL(master->dma_rx))
			return false;
		if (qup->qup_v1 && (xfer->len % qup->in_blk_sz))
			return false;
	}

	if (xfer->tx_buf) {
		if (!IS_ALIGNED((size_t)xfer->tx_buf, dma_align) ||
		    IS_ERR_OR_NULL(master->dma_tx))
			return false;
		if (qup->qup_v1 && (xfer->len % qup->out_blk_sz))
			return false;
	}

	n_words = xfer->len / DIV_ROUND_UP(xfer->bits_per_word, 8);
	if (n_words <= (qup->in_fifo_sz / sizeof(u32)))
		return false;

	return true;
}

static void spi_qup_release_dma(struct spi_master *master)
{
	if (!IS_ERR_OR_NULL(master->dma_rx))
		dma_release_channel(master->dma_rx);
	if (!IS_ERR_OR_NULL(master->dma_tx))
		dma_release_channel(master->dma_tx);
}

static int spi_qup_init_dma(struct spi_master *master, resource_size_t base)
{
	struct spi_qup *spi = spi_master_get_devdata(master);
	struct dma_slave_config *rx_conf = &spi->rx_conf,
				*tx_conf = &spi->tx_conf;
	struct device *dev = spi->dev;
	int ret;

	/* allocate dma resources, if available */
	master->dma_rx = dma_request_slave_channel_reason(dev, "rx");
	if (IS_ERR(master->dma_rx))
		return PTR_ERR(master->dma_rx);

	master->dma_tx = dma_request_slave_channel_reason(dev, "tx");
	if (IS_ERR(master->dma_tx)) {
		ret = PTR_ERR(master->dma_tx);
		goto err_tx;
	}

	/* set DMA parameters */
	rx_conf->direction = DMA_DEV_TO_MEM;
	rx_conf->device_fc = 1;
	rx_conf->src_addr = base + QUP_INPUT_FIFO;
	rx_conf->src_maxburst = spi->in_blk_sz;

	tx_conf->direction = DMA_MEM_TO_DEV;
	tx_conf->device_fc = 1;
	tx_conf->dst_addr = base + QUP_OUTPUT_FIFO;
	tx_conf->dst_maxburst = spi->out_blk_sz;

	ret = dmaengine_slave_config(master->dma_rx, rx_conf);
	if (ret) {
		dev_err(dev, "failed to configure RX channel\n");
		goto err;
	}

	ret = dmaengine_slave_config(master->dma_tx, tx_conf);
	if (ret) {
		dev_err(dev, "failed to configure TX channel\n");
		goto err;
	}

	return 0;

err:
	dma_release_channel(master->dma_tx);
err_tx:
	dma_release_channel(master->dma_rx);
	return ret;
}

static void spi_qup_set_cs(struct spi_device *spi, bool val)
{
	struct spi_qup *controller;
	u32 spi_ioc;
	u32 spi_ioc_orig;

	controller = spi_master_get_devdata(spi->master);
	spi_ioc = readl_relaxed(controller->base + SPI_IO_CONTROL);
	spi_ioc_orig = spi_ioc;
	if (!val)
		spi_ioc |= SPI_IO_C_FORCE_CS;
	else
		spi_ioc &= ~SPI_IO_C_FORCE_CS;

	if (spi_ioc != spi_ioc_orig)
		writel_relaxed(spi_ioc, controller->base + SPI_IO_CONTROL);
}

static int spi_qup_probe(struct platform_device *pdev)
{
	struct spi_master *master;
	struct clk *iclk, *cclk;
	struct spi_qup *controller;
	struct resource *res;
	struct device *dev;
	void __iomem *base;
	u32 max_freq, iomode, num_cs;
	int ret, irq, size;

	dev = &pdev->dev;
	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	base = devm_ioremap_resource(dev, res);
	if (IS_ERR(base))
		return PTR_ERR(base);

	irq = platform_get_irq(pdev, 0);
	if (irq < 0)
		return irq;

	cclk = devm_clk_get(dev, "core");
	if (IS_ERR(cclk))
		return PTR_ERR(cclk);

	iclk = devm_clk_get(dev, "iface");
	if (IS_ERR(iclk))
		return PTR_ERR(iclk);

	/* This is optional parameter */
	if (of_property_read_u32(dev->of_node, "spi-max-frequency", &max_freq))
		max_freq = SPI_MAX_RATE;

	if (!max_freq || max_freq > SPI_MAX_RATE) {
		dev_err(dev, "invalid clock frequency %d\n", max_freq);
		return -ENXIO;
	}

	ret = clk_prepare_enable(cclk);
	if (ret) {
		dev_err(dev, "cannot enable core clock\n");
		return ret;
	}

	ret = clk_prepare_enable(iclk);
	if (ret) {
		clk_disable_unprepare(cclk);
		dev_err(dev, "cannot enable iface clock\n");
		return ret;
	}

	master = spi_alloc_master(dev, sizeof(struct spi_qup));
	if (!master) {
		clk_disable_unprepare(cclk);
		clk_disable_unprepare(iclk);
		dev_err(dev, "cannot allocate master\n");
		return -ENOMEM;
	}

	/* use num-cs unless not present or out of range */
	if (of_property_read_u32(dev->of_node, "num-cs", &num_cs) ||
	    num_cs > SPI_NUM_CHIPSELECTS)
		master->num_chipselect = SPI_NUM_CHIPSELECTS;
	else
		master->num_chipselect = num_cs;

	master->bus_num = pdev->id;
	master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH | SPI_LOOP;
	master->bits_per_word_mask = SPI_BPW_RANGE_MASK(4, 32);
	master->max_speed_hz = max_freq;
	master->transfer_one = spi_qup_transfer_one;
	master->dev.of_node = pdev->dev.of_node;
	master->auto_runtime_pm = true;
	master->dma_alignment = dma_get_cache_alignment();
	master->max_dma_len = SPI_MAX_DMA_XFER;

	platform_set_drvdata(pdev, master);

	controller = spi_master_get_devdata(master);

	controller->dev = dev;
	controller->base = base;
	controller->iclk = iclk;
	controller->cclk = cclk;
	controller->irq = irq;

	ret = spi_qup_init_dma(master, res->start);
	if (ret == -EPROBE_DEFER)
		goto error;
	else if (!ret)
		master->can_dma = spi_qup_can_dma;

	/* set v1 flag if device is version 1 */
	if (of_device_is_compatible(dev->of_node, "qcom,spi-qup-v1.1.1"))
		controller->qup_v1 = 1;

	if (!controller->qup_v1)
		master->set_cs = spi_qup_set_cs;

	spin_lock_init(&controller->lock);
	init_completion(&controller->done);

	iomode = readl_relaxed(base + QUP_IO_M_MODES);

	size = QUP_IO_M_OUTPUT_BLOCK_SIZE(iomode);
	if (size)
		controller->out_blk_sz = size * 16;
	else
		controller->out_blk_sz = 4;

	size = QUP_IO_M_INPUT_BLOCK_SIZE(iomode);
	if (size)
		controller->in_blk_sz = size * 16;
	else
		controller->in_blk_sz = 4;

	size = QUP_IO_M_OUTPUT_FIFO_SIZE(iomode);
	controller->out_fifo_sz = controller->out_blk_sz * (2 << size);

	size = QUP_IO_M_INPUT_FIFO_SIZE(iomode);
	controller->in_fifo_sz = controller->in_blk_sz * (2 << size);

	dev_info(dev, "IN:block:%d, fifo:%d, OUT:block:%d, fifo:%d\n",
		 controller->in_blk_sz, controller->in_fifo_sz,
		 controller->out_blk_sz, controller->out_fifo_sz);

	writel_relaxed(1, base + QUP_SW_RESET);

	ret = spi_qup_set_state(controller, QUP_STATE_RESET);
	if (ret) {
		dev_err(dev, "cannot set RESET state\n");
		goto error_dma;
	}

	writel_relaxed(0, base + QUP_OPERATIONAL);
	writel_relaxed(0, base + QUP_IO_M_MODES);

	if (!controller->qup_v1)
		writel_relaxed(0, base + QUP_OPERATIONAL_MASK);

	writel_relaxed(SPI_ERROR_CLK_UNDER_RUN | SPI_ERROR_CLK_OVER_RUN,
		       base + SPI_ERROR_FLAGS_EN);

	/* if earlier version of the QUP, disable INPUT_OVERRUN */
	if (controller->qup_v1)
		writel_relaxed(QUP_ERROR_OUTPUT_OVER_RUN |
			QUP_ERROR_INPUT_UNDER_RUN | QUP_ERROR_OUTPUT_UNDER_RUN,
			base + QUP_ERROR_FLAGS_EN);

	writel_relaxed(0, base + SPI_CONFIG);
	writel_relaxed(SPI_IO_C_NO_TRI_STATE, base + SPI_IO_CONTROL);

	ret = devm_request_irq(dev, irq, spi_qup_qup_irq,
			       IRQF_TRIGGER_HIGH, pdev->name, controller);
	if (ret)
		goto error_dma;

	pm_runtime_set_autosuspend_delay(dev, MSEC_PER_SEC);
	pm_runtime_use_autosuspend(dev);
	pm_runtime_set_active(dev);
	pm_runtime_enable(dev);

	ret = devm_spi_register_master(dev, master);
	if (ret)
		goto disable_pm;

	return 0;

disable_pm:
	pm_runtime_disable(&pdev->dev);
error_dma:
	spi_qup_release_dma(master);
error:
	clk_disable_unprepare(cclk);
	clk_disable_unprepare(iclk);
	spi_master_put(master);
	return ret;
}

#ifdef CONFIG_PM
static int spi_qup_pm_suspend_runtime(struct device *device)
{
	struct spi_master *master = dev_get_drvdata(device);
	struct spi_qup *controller = spi_master_get_devdata(master);
	u32 config;

	/* Enable clocks auto gaiting */
	config = readl(controller->base + QUP_CONFIG);
	config |= QUP_CONFIG_CLOCK_AUTO_GATE;
	writel_relaxed(config, controller->base + QUP_CONFIG);

	clk_disable_unprepare(controller->cclk);
	clk_disable_unprepare(controller->iclk);

	return 0;
}

static int spi_qup_pm_resume_runtime(struct device *device)
{
	struct spi_master *master = dev_get_drvdata(device);
	struct spi_qup *controller = spi_master_get_devdata(master);
	u32 config;
	int ret;

	ret = clk_prepare_enable(controller->iclk);
	if (ret)
		return ret;

	ret = clk_prepare_enable(controller->cclk);
	if (ret)
		return ret;

	/* Disable clocks auto gaiting */
	config = readl_relaxed(controller->base + QUP_CONFIG);
	config &= ~QUP_CONFIG_CLOCK_AUTO_GATE;
	writel_relaxed(config, controller->base + QUP_CONFIG);
	return 0;
}
#endif /* CONFIG_PM */

#ifdef CONFIG_PM_SLEEP
static int spi_qup_suspend(struct device *device)
{
	struct spi_master *master = dev_get_drvdata(device);
	struct spi_qup *controller = spi_master_get_devdata(master);
	int ret;

	ret = spi_master_suspend(master);
	if (ret)
		return ret;

	ret = spi_qup_set_state(controller, QUP_STATE_RESET);
	if (ret)
		return ret;

	if (!pm_runtime_suspended(device)) {
		clk_disable_unprepare(controller->cclk);
		clk_disable_unprepare(controller->iclk);
	}
	return 0;
}

static int spi_qup_resume(struct device *device)
{
	struct spi_master *master = dev_get_drvdata(device);
	struct spi_qup *controller = spi_master_get_devdata(master);
	int ret;

	ret = clk_prepare_enable(controller->iclk);
	if (ret)
		return ret;

	ret = clk_prepare_enable(controller->cclk);
	if (ret)
		return ret;

	ret = spi_qup_set_state(controller, QUP_STATE_RESET);
	if (ret)
		return ret;

	return spi_master_resume(master);
}
#endif /* CONFIG_PM_SLEEP */

static int spi_qup_remove(struct platform_device *pdev)
{
	struct spi_master *master = dev_get_drvdata(&pdev->dev);
	struct spi_qup *controller = spi_master_get_devdata(master);
	int ret;

	ret = pm_runtime_get_sync(&pdev->dev);
	if (ret < 0)
		return ret;

	ret = spi_qup_set_state(controller, QUP_STATE_RESET);
	if (ret)
		return ret;

	spi_qup_release_dma(master);

	clk_disable_unprepare(controller->cclk);
	clk_disable_unprepare(controller->iclk);

	pm_runtime_put_noidle(&pdev->dev);
	pm_runtime_disable(&pdev->dev);

	return 0;
}

static const struct of_device_id spi_qup_dt_match[] = {
	{ .compatible = "qcom,spi-qup-v1.1.1", },
	{ .compatible = "qcom,spi-qup-v2.1.1", },
	{ .compatible = "qcom,spi-qup-v2.2.1", },
	{ }
};
MODULE_DEVICE_TABLE(of, spi_qup_dt_match);

static const struct dev_pm_ops spi_qup_dev_pm_ops = {
	SET_SYSTEM_SLEEP_PM_OPS(spi_qup_suspend, spi_qup_resume)
	SET_RUNTIME_PM_OPS(spi_qup_pm_suspend_runtime,
			   spi_qup_pm_resume_runtime,
			   NULL)
};

static struct platform_driver spi_qup_driver = {
	.driver = {
		.name		= "spi_qup",
		.pm		= &spi_qup_dev_pm_ops,
		.of_match_table = spi_qup_dt_match,
	},
	.probe = spi_qup_probe,
	.remove = spi_qup_remove,
};
module_platform_driver(spi_qup_driver);

MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:spi_qup");