drivers/spi/spi-synquacer.c - filogic/uboot - Gitiles

 // SPDX-License-Identifier: GPL-2.0+
 /*
  * spi-synquacer.c - Socionext Synquacer SPI driver
  * Copyright 2021 Linaro Ltd.
  * Copyright 2021 Socionext, Inc.
  */

 #include <clk.h>
 #include <dm.h>
 #include <log.h>
 #include <time.h>
 #include <dm/device_compat.h>
 #include <linux/bitfield.h>
 #include <linux/bitops.h>
 #include <linux/delay.h>
 #include <linux/io.h>
 #include <spi.h>
 #include <wait_bit.h>

 #define MCTRL	0x0
 #define MEN	0
 #define CSEN	1
 #define IPCLK	3
 #define MES	4
 #define SYNCON	5

 #define PCC0		0x4
 #define PCC(n)		(PCC0 + (n) * 4)
 #define RTM		3
 #define ACES		2
 #define SAFESYNC	16
 #define CPHA		0
 #define CPOL		1
 #define SSPOL		4
 #define SDIR		7
 #define SS2CD		5
 #define SENDIAN		8
 #define CDRS_SHIFT	9
 #define CDRS_MASK	0x7f

 #define TXF		0x14
 #define TXE		0x18
 #define TXC		0x1c
 #define RXF		0x20
 #define RXE		0x24
 #define RXC		0x28
 #define TFES		1
 #define TFLETE		4
 #define TSSRS		6
 #define RFMTE		5
 #define RSSRS		6

 #define FAULTF		0x2c
 #define FAULTC		0x30

 #define DMCFG		0x34
 #define SSDC		1
 #define MSTARTEN	2

 #define DMSTART		0x38
 #define TRIGGER		0
 #define DMSTOP		8
 #define CS_MASK		3
 #define CS_SHIFT	16
 #define DATA_TXRX	0
 #define DATA_RX		1
 #define DATA_TX		2
 #define DATA_MASK	3
 #define DATA_SHIFT	26
 #define BUS_WIDTH	24

 #define DMBCC		0x3c
 #define DMSTATUS	0x40
 #define RX_DATA_MASK	0x1f
 #define RX_DATA_SHIFT	8
 #define TX_DATA_MASK	0x1f
 #define TX_DATA_SHIFT	16

 #define TXBITCNT	0x44

 #define FIFOCFG		0x4c
 #define BPW_MASK	0x3
 #define BPW_SHIFT	8
 #define RX_FLUSH	11
 #define TX_FLUSH	12
 #define RX_TRSHLD_MASK		0xf
 #define RX_TRSHLD_SHIFT		0
 #define TX_TRSHLD_MASK		0xf
 #define TX_TRSHLD_SHIFT		4

 #define TXFIFO		0x50
 #define RXFIFO		0x90
 #define MID		0xfc

 #define FIFO_DEPTH	16
 #define TX_TRSHLD	4
 #define RX_TRSHLD	(FIFO_DEPTH - TX_TRSHLD)

 #define TXBIT	1
 #define RXBIT	2

 DECLARE_GLOBAL_DATA_PTR;

 struct synquacer_spi_plat {
 	void __iomem *base;
 	bool aces, rtm;
 };

 struct synquacer_spi_priv {
 	void __iomem *base;
 	bool aces, rtm;
 	int speed, cs, mode, rwflag;
 	void *rx_buf;
 	const void *tx_buf;
 	unsigned int tx_words, rx_words;
 };

 static void read_fifo(struct synquacer_spi_priv *priv)
 {
 	u32 len = readl(priv->base + DMSTATUS);
 	u8 *buf = priv->rx_buf;
 	int i;

 	len = (len >> RX_DATA_SHIFT) & RX_DATA_MASK;
 	len = min_t(unsigned int, len, priv->rx_words);

 	for (i = 0; i < len; i++)
 		*buf++ = readb(priv->base + RXFIFO);

 	priv->rx_buf = buf;
 	priv->rx_words -= len;
 }

 static void write_fifo(struct synquacer_spi_priv *priv)
 {
 	u32 len = readl(priv->base + DMSTATUS);
 	const u8 *buf = priv->tx_buf;
 	int i;

 	len = (len >> TX_DATA_SHIFT) & TX_DATA_MASK;
 	len = min_t(unsigned int, FIFO_DEPTH - len, priv->tx_words);

 	for (i = 0; i < len; i++)
 		writeb(*buf++, priv->base + TXFIFO);

 	priv->tx_buf = buf;
 	priv->tx_words -= len;
 }

 static void synquacer_cs_set(struct synquacer_spi_priv *priv, bool active)
 {
 	u32 val;

 	val = readl(priv->base + DMSTART);
 	val &= ~(CS_MASK << CS_SHIFT);
 	val |= priv->cs << CS_SHIFT;

 	if (active) {
 		writel(val, priv->base + DMSTART);

 		val = readl(priv->base + DMSTART);
 		val &= ~BIT(DMSTOP);
 		writel(val, priv->base + DMSTART);
 	} else {
 		val |= BIT(DMSTOP);
 		writel(val, priv->base + DMSTART);

 		if (priv->rx_buf) {
 			u32 buf[16];

 			priv->rx_buf = buf;
 			priv->rx_words = 16;
 			read_fifo(priv);
 		}

 		/* wait until slave is deselected */
 		while (!(readl(priv->base + TXF) & BIT(TSSRS)) ||
 		       !(readl(priv->base + RXF) & BIT(RSSRS)))
 			;
 	}
 }

 static void synquacer_spi_config(struct udevice *dev, void *rx, const void *tx)
 {
 	struct udevice *bus = dev->parent;
 	struct synquacer_spi_priv *priv = dev_get_priv(bus);
 	struct dm_spi_slave_plat *slave_plat = dev_get_parent_plat(dev);
 	u32 val, div, bus_width;
 	int rwflag;

 	rwflag = (rx ? 1 : 0) | (tx ? 2 : 0);

 	/* if nothing to do */
 	if (slave_plat->mode == priv->mode &&
 	    rwflag == priv->rwflag &&
 	    slave_plat->cs == priv->cs &&
 	    slave_plat->max_hz == priv->speed)
 		return;

 	priv->rwflag = rwflag;
 	priv->cs = slave_plat->cs;
 	priv->mode = slave_plat->mode;
 	priv->speed = slave_plat->max_hz;

 	if (priv->mode & SPI_TX_DUAL)
 		bus_width = 2;
 	else if (priv->mode & SPI_TX_QUAD)
 		bus_width = 4;
 	else if (priv->mode & SPI_TX_OCTAL)
 		bus_width = 8;
 	else
 		bus_width = 1; /* default is single bit mode */

 	div = DIV_ROUND_UP(125000000, priv->speed);

 	val = readl(priv->base + PCC(priv->cs));
 	val &= ~BIT(RTM);
 	val &= ~BIT(ACES);
 	val &= ~BIT(SAFESYNC);
 	if ((priv->mode & (SPI_TX_DUAL | SPI_RX_DUAL)) && div < 3)
 		val |= BIT(SAFESYNC);
 	if ((priv->mode & (SPI_TX_QUAD | SPI_RX_QUAD)) && div < 6)
 		val |= BIT(SAFESYNC);

 	if (priv->mode & SPI_CPHA)
 		val |= BIT(CPHA);
 	else
 		val &= ~BIT(CPHA);

 	if (priv->mode & SPI_CPOL)
 		val |= BIT(CPOL);
 	else
 		val &= ~BIT(CPOL);

 	if (priv->mode & SPI_CS_HIGH)
 		val |= BIT(SSPOL);
 	else
 		val &= ~BIT(SSPOL);

 	if (priv->mode & SPI_LSB_FIRST)
 		val |= BIT(SDIR);
 	else
 		val &= ~BIT(SDIR);

 	if (priv->aces)
 		val |= BIT(ACES);

 	if (priv->rtm)
 		val |= BIT(RTM);

 	val |= (3 << SS2CD);
 	val |= BIT(SENDIAN);

 	val &= ~(CDRS_MASK << CDRS_SHIFT);
 	val |= ((div >> 1) << CDRS_SHIFT);

 	writel(val, priv->base + PCC(priv->cs));

 	val = readl(priv->base + FIFOCFG);
 	val &= ~(BPW_MASK << BPW_SHIFT);
 	val |= (0 << BPW_SHIFT);
 	writel(val, priv->base + FIFOCFG);

 	val = readl(priv->base + DMSTART);
 	val &= ~(DATA_MASK << DATA_SHIFT);

 	if (tx && rx)
 		val |= (DATA_TXRX << DATA_SHIFT);
 	else if (rx)
 		val |= (DATA_RX << DATA_SHIFT);
 	else
 		val |= (DATA_TX << DATA_SHIFT);

 	val &= ~(3 << BUS_WIDTH);
 	val |= ((bus_width >> 1) << BUS_WIDTH);
 	writel(val, priv->base + DMSTART);
 }

 static int synquacer_spi_xfer(struct udevice *dev, unsigned int bitlen,
 			      const void *tx_buf, void *rx_buf,
 			      unsigned long flags)
 {
 	struct udevice *bus = dev->parent;
 	struct synquacer_spi_priv *priv = dev_get_priv(bus);
 	u32 val, words, busy = 0;

 	val = readl(priv->base + FIFOCFG);
 	val |= (1 << RX_FLUSH);
 	val |= (1 << TX_FLUSH);
 	writel(val, priv->base + FIFOCFG);

 	synquacer_spi_config(dev, rx_buf, tx_buf);

 	priv->tx_buf = tx_buf;
 	priv->rx_buf = rx_buf;

 	words = bitlen / 8;

 	if (tx_buf) {
 		busy |= BIT(TXBIT);
 		priv->tx_words = words;
 	} else {
 		busy &= ~BIT(TXBIT);
 		priv->tx_words = 0;
 	}

 	if (rx_buf) {
 		busy |= BIT(RXBIT);
 		priv->rx_words = words;
 	} else {
 		busy &= ~BIT(RXBIT);
 		priv->rx_words = 0;
 	}

 	if (flags & SPI_XFER_BEGIN)
 		synquacer_cs_set(priv, true);

 	if (tx_buf)
 		write_fifo(priv);

 	if (rx_buf) {
 		val = readl(priv->base + FIFOCFG);
 		val &= ~(RX_TRSHLD_MASK << RX_TRSHLD_SHIFT);
 		val |= ((priv->rx_words > FIFO_DEPTH ?
 			RX_TRSHLD : priv->rx_words) << RX_TRSHLD_SHIFT);
 		writel(val, priv->base + FIFOCFG);
 	}

 	writel(~0, priv->base + TXC);
 	writel(~0, priv->base + RXC);

 	/* Trigger */
 	if (flags & SPI_XFER_BEGIN) {
 		val = readl(priv->base + DMSTART);
 		val |= BIT(TRIGGER);
 		writel(val, priv->base + DMSTART);
 	}

 	while (busy & (BIT(RXBIT) | BIT(TXBIT))) {
 		if (priv->rx_words)
 			read_fifo(priv);
 		else
 			busy &= ~BIT(RXBIT);

 		if (priv->tx_words) {
 			write_fifo(priv);
 		} else {
 			/* wait for shifter to empty out */
 			while (!(readl(priv->base + TXF) & BIT(TFES)))
 				cpu_relax();

 			busy &= ~BIT(TXBIT);
 		}
 	}

 	if (flags & SPI_XFER_END)
 		synquacer_cs_set(priv, false);

 	return 0;
 }

 static int synquacer_spi_set_speed(struct udevice *bus, uint speed)
 {
 	return 0;
 }

 static int synquacer_spi_set_mode(struct udevice *bus, uint mode)
 {
 	return 0;
 }

 static int synquacer_spi_claim_bus(struct udevice *dev)
 {
 	return 0;
 }

 static int synquacer_spi_release_bus(struct udevice *dev)
 {
 	return 0;
 }

 static void synquacer_spi_disable_module(struct synquacer_spi_priv *priv)
 {
 	writel(0, priv->base + MCTRL);
 	while (readl(priv->base + MCTRL) & BIT(MES))
 		cpu_relax();
 }

 static void synquacer_spi_init(struct synquacer_spi_priv *priv)
 {
 	u32 val;

 	synquacer_spi_disable_module(priv);

 	writel(0, priv->base + TXE);
 	writel(0, priv->base + RXE);
 	val = readl(priv->base + TXF);
 	writel(val, priv->base + TXC);
 	val = readl(priv->base + RXF);
 	writel(val, priv->base + RXC);
 	val = readl(priv->base + FAULTF);
 	writel(val, priv->base + FAULTC);

 	val = readl(priv->base + DMCFG);
 	val &= ~BIT(SSDC);
 	val &= ~BIT(MSTARTEN);
 	writel(val, priv->base + DMCFG);

 	/* Enable module with direct mode */
 	val = readl(priv->base + MCTRL);
 	val &= ~BIT(IPCLK);
 	val &= ~BIT(CSEN);
 	val |= BIT(MEN);
 	val |= BIT(SYNCON);
 	writel(val, priv->base + MCTRL);
 }

 static void synquacer_spi_exit(struct synquacer_spi_priv *priv)
 {
 	u32 val;

 	synquacer_spi_disable_module(priv);

 	/* Enable module with command sequence mode */
 	val = readl(priv->base + MCTRL);
 	val &= ~BIT(IPCLK);
 	val |= BIT(CSEN);
 	val |= BIT(MEN);
 	val |= BIT(SYNCON);
 	writel(val, priv->base + MCTRL);

 	while (!(readl(priv->base + MCTRL) & BIT(MES)))
 		cpu_relax();
 }

 static int synquacer_spi_probe(struct udevice *bus)
 {
 	struct synquacer_spi_plat *plat = dev_get_plat(bus);
 	struct synquacer_spi_priv *priv = dev_get_priv(bus);

 	priv->base = plat->base;
 	priv->aces = plat->aces;
 	priv->rtm = plat->rtm;

 	synquacer_spi_init(priv);
 	return 0;
 }

 static int synquacer_spi_remove(struct udevice *bus)
 {
 	struct synquacer_spi_priv *priv = dev_get_priv(bus);

 	synquacer_spi_exit(priv);
 	return 0;
 }

 static int synquacer_spi_of_to_plat(struct udevice *bus)
 {
 	struct synquacer_spi_plat *plat = dev_get_plat(bus);
 	struct clk clk;

 	plat->base = dev_read_addr_ptr(bus);

 	plat->aces = dev_read_bool(bus, "socionext,set-aces");
 	plat->rtm = dev_read_bool(bus, "socionext,use-rtm");

 	clk_get_by_name(bus, "iHCLK", &clk);
 	clk_enable(&clk);

 	return 0;
 }

 static const struct dm_spi_ops synquacer_spi_ops = {
 	.claim_bus	= synquacer_spi_claim_bus,
 	.release_bus	= synquacer_spi_release_bus,
 	.xfer		= synquacer_spi_xfer,
 	.set_speed	= synquacer_spi_set_speed,
 	.set_mode	= synquacer_spi_set_mode,
 };

 static const struct udevice_id synquacer_spi_ids[] = {
 	{ .compatible = "socionext,synquacer-spi" },
 	{ /* Sentinel */ }
 };

 U_BOOT_DRIVER(synquacer_spi) = {
 	.name		= "synquacer_spi",
 	.id		= UCLASS_SPI,
 	.of_match	= synquacer_spi_ids,
 	.ops		= &synquacer_spi_ops,
 	.of_to_plat	= synquacer_spi_of_to_plat,
 	.plat_auto	= sizeof(struct synquacer_spi_plat),
 	.priv_auto	= sizeof(struct synquacer_spi_priv),
 	.probe		= synquacer_spi_probe,
 	.flags		= DM_FLAG_OS_PREPARE,
 	.remove		= synquacer_spi_remove,
 };
	// SPDX-License-Identifier: GPL-2.0+
	/*
	* spi-synquacer.c - Socionext Synquacer SPI driver
	* Copyright 2021 Linaro Ltd.
	* Copyright 2021 Socionext, Inc.
	*/

	#include <clk.h>
	#include <dm.h>
	#include <log.h>
	#include <time.h>
	#include <dm/device_compat.h>
	#include <linux/bitfield.h>
	#include <linux/bitops.h>
	#include <linux/delay.h>
	#include <linux/io.h>
	#include <spi.h>
	#include <wait_bit.h>

	#define MCTRL 0x0
	#define MEN 0
	#define CSEN 1
	#define IPCLK 3
	#define MES 4
	#define SYNCON 5

	#define PCC0 0x4
	#define PCC(n) (PCC0 + (n) * 4)
	#define RTM 3
	#define ACES 2
	#define SAFESYNC 16
	#define CPHA 0
	#define CPOL 1
	#define SSPOL 4
	#define SDIR 7
	#define SS2CD 5
	#define SENDIAN 8
	#define CDRS_SHIFT 9
	#define CDRS_MASK 0x7f

	#define TXF 0x14
	#define TXE 0x18
	#define TXC 0x1c
	#define RXF 0x20
	#define RXE 0x24
	#define RXC 0x28
	#define TFES 1
	#define TFLETE 4
	#define TSSRS 6
	#define RFMTE 5
	#define RSSRS 6

	#define FAULTF 0x2c
	#define FAULTC 0x30

	#define DMCFG 0x34
	#define SSDC 1
	#define MSTARTEN 2

	#define DMSTART 0x38
	#define TRIGGER 0
	#define DMSTOP 8
	#define CS_MASK 3
	#define CS_SHIFT 16
	#define DATA_TXRX 0
	#define DATA_RX 1
	#define DATA_TX 2
	#define DATA_MASK 3
	#define DATA_SHIFT 26
	#define BUS_WIDTH 24

	#define DMBCC 0x3c
	#define DMSTATUS 0x40
	#define RX_DATA_MASK 0x1f
	#define RX_DATA_SHIFT 8
	#define TX_DATA_MASK 0x1f
	#define TX_DATA_SHIFT 16

	#define TXBITCNT 0x44

	#define FIFOCFG 0x4c
	#define BPW_MASK 0x3
	#define BPW_SHIFT 8
	#define RX_FLUSH 11
	#define TX_FLUSH 12
	#define RX_TRSHLD_MASK 0xf
	#define RX_TRSHLD_SHIFT 0
	#define TX_TRSHLD_MASK 0xf
	#define TX_TRSHLD_SHIFT 4

	#define TXFIFO 0x50
	#define RXFIFO 0x90
	#define MID 0xfc

	#define FIFO_DEPTH 16
	#define TX_TRSHLD 4
	#define RX_TRSHLD (FIFO_DEPTH - TX_TRSHLD)

	#define TXBIT 1
	#define RXBIT 2

	DECLARE_GLOBAL_DATA_PTR;

	struct synquacer_spi_plat {
	void __iomem *base;
	bool aces, rtm;
	};

	struct synquacer_spi_priv {
	void __iomem *base;
	bool aces, rtm;
	int speed, cs, mode, rwflag;
	void *rx_buf;
	const void *tx_buf;
	unsigned int tx_words, rx_words;
	};

	static void read_fifo(struct synquacer_spi_priv *priv)
	{
	u32 len = readl(priv->base + DMSTATUS);
	u8 *buf = priv->rx_buf;
	int i;

	len = (len >> RX_DATA_SHIFT) & RX_DATA_MASK;
	len = min_t(unsigned int, len, priv->rx_words);

	for (i = 0; i < len; i++)
	*buf++ = readb(priv->base + RXFIFO);

	priv->rx_buf = buf;
	priv->rx_words -= len;
	}

	static void write_fifo(struct synquacer_spi_priv *priv)
	{
	u32 len = readl(priv->base + DMSTATUS);
	const u8 *buf = priv->tx_buf;
	int i;

	len = (len >> TX_DATA_SHIFT) & TX_DATA_MASK;
	len = min_t(unsigned int, FIFO_DEPTH - len, priv->tx_words);

	for (i = 0; i < len; i++)
	writeb(*buf++, priv->base + TXFIFO);

	priv->tx_buf = buf;
	priv->tx_words -= len;
	}

	static void synquacer_cs_set(struct synquacer_spi_priv *priv, bool active)
	{
	u32 val;

	val = readl(priv->base + DMSTART);
	val &= ~(CS_MASK << CS_SHIFT);
	val \|= priv->cs << CS_SHIFT;

	if (active) {
	writel(val, priv->base + DMSTART);

	val = readl(priv->base + DMSTART);
	val &= ~BIT(DMSTOP);
	writel(val, priv->base + DMSTART);
	} else {
	val \|= BIT(DMSTOP);
	writel(val, priv->base + DMSTART);

	if (priv->rx_buf) {
	u32 buf[16];

	priv->rx_buf = buf;
	priv->rx_words = 16;
	read_fifo(priv);
	}

	/* wait until slave is deselected */
	while (!(readl(priv->base + TXF) & BIT(TSSRS)) \|\|
	!(readl(priv->base + RXF) & BIT(RSSRS)))
	;
	}
	}

	static void synquacer_spi_config(struct udevice dev, void rx, const void *tx)
	{
	struct udevice *bus = dev->parent;
	struct synquacer_spi_priv *priv = dev_get_priv(bus);
	struct dm_spi_slave_plat *slave_plat = dev_get_parent_plat(dev);
	u32 val, div, bus_width;
	int rwflag;

	rwflag = (rx ? 1 : 0) \| (tx ? 2 : 0);

	/* if nothing to do */
	if (slave_plat->mode == priv->mode &&
	rwflag == priv->rwflag &&
	slave_plat->cs == priv->cs &&
	slave_plat->max_hz == priv->speed)
	return;

	priv->rwflag = rwflag;
	priv->cs = slave_plat->cs;
	priv->mode = slave_plat->mode;
	priv->speed = slave_plat->max_hz;

	if (priv->mode & SPI_TX_DUAL)
	bus_width = 2;
	else if (priv->mode & SPI_TX_QUAD)
	bus_width = 4;
	else if (priv->mode & SPI_TX_OCTAL)
	bus_width = 8;
	else
	bus_width = 1; /* default is single bit mode */

	div = DIV_ROUND_UP(125000000, priv->speed);

	val = readl(priv->base + PCC(priv->cs));
	val &= ~BIT(RTM);
	val &= ~BIT(ACES);
	val &= ~BIT(SAFESYNC);
	if ((priv->mode & (SPI_TX_DUAL \| SPI_RX_DUAL)) && div < 3)
	val \|= BIT(SAFESYNC);
	if ((priv->mode & (SPI_TX_QUAD \| SPI_RX_QUAD)) && div < 6)
	val \|= BIT(SAFESYNC);

	if (priv->mode & SPI_CPHA)
	val \|= BIT(CPHA);
	else
	val &= ~BIT(CPHA);

	if (priv->mode & SPI_CPOL)
	val \|= BIT(CPOL);
	else
	val &= ~BIT(CPOL);

	if (priv->mode & SPI_CS_HIGH)
	val \|= BIT(SSPOL);
	else
	val &= ~BIT(SSPOL);

	if (priv->mode & SPI_LSB_FIRST)
	val \|= BIT(SDIR);
	else
	val &= ~BIT(SDIR);

	if (priv->aces)
	val \|= BIT(ACES);

	if (priv->rtm)
	val \|= BIT(RTM);

	val \|= (3 << SS2CD);
	val \|= BIT(SENDIAN);

	val &= ~(CDRS_MASK << CDRS_SHIFT);
	val \|= ((div >> 1) << CDRS_SHIFT);

	writel(val, priv->base + PCC(priv->cs));

	val = readl(priv->base + FIFOCFG);
	val &= ~(BPW_MASK << BPW_SHIFT);
	val \|= (0 << BPW_SHIFT);
	writel(val, priv->base + FIFOCFG);

	val = readl(priv->base + DMSTART);
	val &= ~(DATA_MASK << DATA_SHIFT);

	if (tx && rx)
	val \|= (DATA_TXRX << DATA_SHIFT);
	else if (rx)
	val \|= (DATA_RX << DATA_SHIFT);
	else
	val \|= (DATA_TX << DATA_SHIFT);

	val &= ~(3 << BUS_WIDTH);
	val \|= ((bus_width >> 1) << BUS_WIDTH);
	writel(val, priv->base + DMSTART);
	}

	static int synquacer_spi_xfer(struct udevice *dev, unsigned int bitlen,
	const void tx_buf, void rx_buf,
	unsigned long flags)
	{
	struct udevice *bus = dev->parent;
	struct synquacer_spi_priv *priv = dev_get_priv(bus);
	u32 val, words, busy = 0;

	val = readl(priv->base + FIFOCFG);
	val \|= (1 << RX_FLUSH);
	val \|= (1 << TX_FLUSH);
	writel(val, priv->base + FIFOCFG);

	synquacer_spi_config(dev, rx_buf, tx_buf);

	priv->tx_buf = tx_buf;
	priv->rx_buf = rx_buf;

	words = bitlen / 8;

	if (tx_buf) {
	busy \|= BIT(TXBIT);
	priv->tx_words = words;
	} else {
	busy &= ~BIT(TXBIT);
	priv->tx_words = 0;
	}

	if (rx_buf) {
	busy \|= BIT(RXBIT);
	priv->rx_words = words;
	} else {
	busy &= ~BIT(RXBIT);
	priv->rx_words = 0;
	}

	if (flags & SPI_XFER_BEGIN)
	synquacer_cs_set(priv, true);

	if (tx_buf)
	write_fifo(priv);

	if (rx_buf) {
	val = readl(priv->base + FIFOCFG);
	val &= ~(RX_TRSHLD_MASK << RX_TRSHLD_SHIFT);
	val \|= ((priv->rx_words > FIFO_DEPTH ?
	RX_TRSHLD : priv->rx_words) << RX_TRSHLD_SHIFT);
	writel(val, priv->base + FIFOCFG);
	}

	writel(~0, priv->base + TXC);
	writel(~0, priv->base + RXC);

	/* Trigger */
	if (flags & SPI_XFER_BEGIN) {
	val = readl(priv->base + DMSTART);
	val \|= BIT(TRIGGER);
	writel(val, priv->base + DMSTART);
	}

	while (busy & (BIT(RXBIT) \| BIT(TXBIT))) {
	if (priv->rx_words)
	read_fifo(priv);
	else
	busy &= ~BIT(RXBIT);

	if (priv->tx_words) {
	write_fifo(priv);
	} else {
	/* wait for shifter to empty out */
	while (!(readl(priv->base + TXF) & BIT(TFES)))
	cpu_relax();

	busy &= ~BIT(TXBIT);
	}
	}

	if (flags & SPI_XFER_END)
	synquacer_cs_set(priv, false);

	return 0;
	}

	static int synquacer_spi_set_speed(struct udevice *bus, uint speed)
	{
	return 0;
	}

	static int synquacer_spi_set_mode(struct udevice *bus, uint mode)
	{
	return 0;
	}

	static int synquacer_spi_claim_bus(struct udevice *dev)
	{
	return 0;
	}

	static int synquacer_spi_release_bus(struct udevice *dev)
	{
	return 0;
	}

	static void synquacer_spi_disable_module(struct synquacer_spi_priv *priv)
	{
	writel(0, priv->base + MCTRL);
	while (readl(priv->base + MCTRL) & BIT(MES))
	cpu_relax();
	}

	static void synquacer_spi_init(struct synquacer_spi_priv *priv)
	{
	u32 val;

	synquacer_spi_disable_module(priv);

	writel(0, priv->base + TXE);
	writel(0, priv->base + RXE);
	val = readl(priv->base + TXF);
	writel(val, priv->base + TXC);
	val = readl(priv->base + RXF);
	writel(val, priv->base + RXC);
	val = readl(priv->base + FAULTF);
	writel(val, priv->base + FAULTC);

	val = readl(priv->base + DMCFG);
	val &= ~BIT(SSDC);
	val &= ~BIT(MSTARTEN);
	writel(val, priv->base + DMCFG);

	/* Enable module with direct mode */
	val = readl(priv->base + MCTRL);
	val &= ~BIT(IPCLK);
	val &= ~BIT(CSEN);
	val \|= BIT(MEN);
	val \|= BIT(SYNCON);
	writel(val, priv->base + MCTRL);
	}

	static void synquacer_spi_exit(struct synquacer_spi_priv *priv)
	{
	u32 val;

	synquacer_spi_disable_module(priv);

	/* Enable module with command sequence mode */
	val = readl(priv->base + MCTRL);
	val &= ~BIT(IPCLK);
	val \|= BIT(CSEN);
	val \|= BIT(MEN);
	val \|= BIT(SYNCON);
	writel(val, priv->base + MCTRL);

	while (!(readl(priv->base + MCTRL) & BIT(MES)))
	cpu_relax();
	}

	static int synquacer_spi_probe(struct udevice *bus)
	{
	struct synquacer_spi_plat *plat = dev_get_plat(bus);
	struct synquacer_spi_priv *priv = dev_get_priv(bus);

	priv->base = plat->base;
	priv->aces = plat->aces;
	priv->rtm = plat->rtm;

	synquacer_spi_init(priv);
	return 0;
	}

	static int synquacer_spi_remove(struct udevice *bus)
	{
	struct synquacer_spi_priv *priv = dev_get_priv(bus);

	synquacer_spi_exit(priv);
	return 0;
	}

	static int synquacer_spi_of_to_plat(struct udevice *bus)
	{
	struct synquacer_spi_plat *plat = dev_get_plat(bus);
	struct clk clk;

	plat->base = dev_read_addr_ptr(bus);

	plat->aces = dev_read_bool(bus, "socionext,set-aces");
	plat->rtm = dev_read_bool(bus, "socionext,use-rtm");

	clk_get_by_name(bus, "iHCLK", &clk);
	clk_enable(&clk);

	return 0;
	}

	static const struct dm_spi_ops synquacer_spi_ops = {
	.claim_bus = synquacer_spi_claim_bus,
	.release_bus = synquacer_spi_release_bus,
	.xfer = synquacer_spi_xfer,
	.set_speed = synquacer_spi_set_speed,
	.set_mode = synquacer_spi_set_mode,
	};

	static const struct udevice_id synquacer_spi_ids[] = {
	{ .compatible = "socionext,synquacer-spi" },
	{ /* Sentinel */ }
	};

	U_BOOT_DRIVER(synquacer_spi) = {
	.name = "synquacer_spi",
	.id = UCLASS_SPI,
	.of_match = synquacer_spi_ids,
	.ops = &synquacer_spi_ops,
	.of_to_plat = synquacer_spi_of_to_plat,
	.plat_auto = sizeof(struct synquacer_spi_plat),
	.priv_auto = sizeof(struct synquacer_spi_priv),
	.probe = synquacer_spi_probe,
	.flags = DM_FLAG_OS_PREPARE,
	.remove = synquacer_spi_remove,
	};