drivers/spi/xilinx_spi.c - platform/external/u-boot - Gitiles

 // SPDX-License-Identifier: GPL-2.0+
 /*
  * Xilinx SPI driver
  *
  * Supports 8 bit SPI transfers only, with or w/o FIFO
  *
  * Based on bfin_spi.c, by way of altera_spi.c
  * Copyright (c) 2015 Jagan Teki <jteki@openedev.com>
  * Copyright (c) 2012 Stephan Linz <linz@li-pro.net>
  * Copyright (c) 2010 Graeme Smecher <graeme.smecher@mail.mcgill.ca>
  * Copyright (c) 2010 Thomas Chou <thomas@wytron.com.tw>
  * Copyright (c) 2005-2008 Analog Devices Inc.
  */

 #include <config.h>
 #include <common.h>
 #include <dm.h>
 #include <errno.h>
 #include <log.h>
 #include <malloc.h>
 #include <spi.h>
 #include <asm/io.h>
 #include <wait_bit.h>

 /*
  * [0]: http://www.xilinx.com/support/documentation
  *
  * Xilinx SPI Register Definitions
  * [1]:	[0]/ip_documentation/xps_spi.pdf
  *	page 8, Register Descriptions
  * [2]:	[0]/ip_documentation/axi_spi_ds742.pdf
  *	page 7, Register Overview Table
  */

 /* SPI Control Register (spicr), [1] p9, [2] p8 */
 #define SPICR_LSB_FIRST		BIT(9)
 #define SPICR_MASTER_INHIBIT	BIT(8)
 #define SPICR_MANUAL_SS		BIT(7)
 #define SPICR_RXFIFO_RESEST	BIT(6)
 #define SPICR_TXFIFO_RESEST	BIT(5)
 #define SPICR_CPHA		BIT(4)
 #define SPICR_CPOL		BIT(3)
 #define SPICR_MASTER_MODE	BIT(2)
 #define SPICR_SPE		BIT(1)
 #define SPICR_LOOP		BIT(0)

 /* SPI Status Register (spisr), [1] p11, [2] p10 */
 #define SPISR_SLAVE_MODE_SELECT	BIT(5)
 #define SPISR_MODF		BIT(4)
 #define SPISR_TX_FULL		BIT(3)
 #define SPISR_TX_EMPTY		BIT(2)
 #define SPISR_RX_FULL		BIT(1)
 #define SPISR_RX_EMPTY		BIT(0)

 /* SPI Data Transmit Register (spidtr), [1] p12, [2] p12 */
 #define SPIDTR_8BIT_MASK	GENMASK(7, 0)
 #define SPIDTR_16BIT_MASK	GENMASK(15, 0)
 #define SPIDTR_32BIT_MASK	GENMASK(31, 0)

 /* SPI Data Receive Register (spidrr), [1] p12, [2] p12 */
 #define SPIDRR_8BIT_MASK	GENMASK(7, 0)
 #define SPIDRR_16BIT_MASK	GENMASK(15, 0)
 #define SPIDRR_32BIT_MASK	GENMASK(31, 0)

 /* SPI Slave Select Register (spissr), [1] p13, [2] p13 */
 #define SPISSR_MASK(cs)		(1 << (cs))
 #define SPISSR_ACT(cs)		~SPISSR_MASK(cs)
 #define SPISSR_OFF		~0UL

 /* SPI Software Reset Register (ssr) */
 #define SPISSR_RESET_VALUE	0x0a

 #define XILSPI_MAX_XFER_BITS	8
 #define XILSPI_SPICR_DFLT_ON	(SPICR_MANUAL_SS | SPICR_MASTER_MODE | \
 				SPICR_SPE)
 #define XILSPI_SPICR_DFLT_OFF	(SPICR_MASTER_INHIBIT | SPICR_MANUAL_SS)

 #ifndef CONFIG_XILINX_SPI_IDLE_VAL
 #define CONFIG_XILINX_SPI_IDLE_VAL	GENMASK(7, 0)
 #endif

 #define XILINX_SPISR_TIMEOUT	10000 /* in milliseconds */

 /* xilinx spi register set */
 struct xilinx_spi_regs {
 	u32 __space0__[7];
 	u32 dgier;	/* Device Global Interrupt Enable Register (DGIER) */
 	u32 ipisr;	/* IP Interrupt Status Register (IPISR) */
 	u32 __space1__;
 	u32 ipier;	/* IP Interrupt Enable Register (IPIER) */
 	u32 __space2__[5];
 	u32 srr;	/* Softare Reset Register (SRR) */
 	u32 __space3__[7];
 	u32 spicr;	/* SPI Control Register (SPICR) */
 	u32 spisr;	/* SPI Status Register (SPISR) */
 	u32 spidtr;	/* SPI Data Transmit Register (SPIDTR) */
 	u32 spidrr;	/* SPI Data Receive Register (SPIDRR) */
 	u32 spissr;	/* SPI Slave Select Register (SPISSR) */
 	u32 spitfor;	/* SPI Transmit FIFO Occupancy Register (SPITFOR) */
 	u32 spirfor;	/* SPI Receive FIFO Occupancy Register (SPIRFOR) */
 };

 /* xilinx spi priv */
 struct xilinx_spi_priv {
 	struct xilinx_spi_regs *regs;
 	unsigned int freq;
 	unsigned int mode;
 	unsigned int fifo_depth;
 	u8 startup;
 };

 static int xilinx_spi_probe(struct udevice *bus)
 {
 	struct xilinx_spi_priv *priv = dev_get_priv(bus);
 	struct xilinx_spi_regs *regs = priv->regs;

 	priv->regs = (struct xilinx_spi_regs *)dev_read_addr(bus);

 	priv->fifo_depth = dev_read_u32_default(bus, "fifo-size", 0);

 	writel(SPISSR_RESET_VALUE, &regs->srr);

 	return 0;
 }

 static void spi_cs_activate(struct udevice *dev, uint cs)
 {
 	struct udevice *bus = dev_get_parent(dev);
 	struct xilinx_spi_priv *priv = dev_get_priv(bus);
 	struct xilinx_spi_regs *regs = priv->regs;

 	writel(SPISSR_ACT(cs), &regs->spissr);
 }

 static void spi_cs_deactivate(struct udevice *dev)
 {
 	struct udevice *bus = dev_get_parent(dev);
 	struct xilinx_spi_priv *priv = dev_get_priv(bus);
 	struct xilinx_spi_regs *regs = priv->regs;

 	writel(SPISSR_OFF, &regs->spissr);
 }

 static int xilinx_spi_claim_bus(struct udevice *dev)
 {
 	struct udevice *bus = dev_get_parent(dev);
 	struct xilinx_spi_priv *priv = dev_get_priv(bus);
 	struct xilinx_spi_regs *regs = priv->regs;

 	writel(SPISSR_OFF, &regs->spissr);
 	writel(XILSPI_SPICR_DFLT_ON, &regs->spicr);

 	return 0;
 }

 static int xilinx_spi_release_bus(struct udevice *dev)
 {
 	struct udevice *bus = dev_get_parent(dev);
 	struct xilinx_spi_priv *priv = dev_get_priv(bus);
 	struct xilinx_spi_regs *regs = priv->regs;

 	writel(SPISSR_OFF, &regs->spissr);
 	writel(XILSPI_SPICR_DFLT_OFF, &regs->spicr);

 	return 0;
 }

 static u32 xilinx_spi_fill_txfifo(struct udevice *bus, const u8 *txp,
 				  u32 txbytes)
 {
 	struct xilinx_spi_priv *priv = dev_get_priv(bus);
 	struct xilinx_spi_regs *regs = priv->regs;
 	unsigned char d;
 	u32 i = 0;

 	while (txbytes && !(readl(&regs->spisr) & SPISR_TX_FULL) &&
 	       i < priv->fifo_depth) {
 		d = txp ? *txp++ : CONFIG_XILINX_SPI_IDLE_VAL;
 		debug("spi_xfer: tx:%x ", d);
 		/* write out and wait for processing (receive data) */
 		writel(d & SPIDTR_8BIT_MASK, &regs->spidtr);
 		txbytes--;
 		i++;
 	}

 	return i;
 }

 static u32 xilinx_spi_read_rxfifo(struct udevice *bus, u8 *rxp, u32 rxbytes)
 {
 	struct xilinx_spi_priv *priv = dev_get_priv(bus);
 	struct xilinx_spi_regs *regs = priv->regs;
 	unsigned char d;
 	unsigned int i = 0;

 	while (rxbytes && !(readl(&regs->spisr) & SPISR_RX_EMPTY)) {
 		d = readl(&regs->spidrr) & SPIDRR_8BIT_MASK;
 		if (rxp)
 			*rxp++ = d;
 		debug("spi_xfer: rx:%x\n", d);
 		rxbytes--;
 		i++;
 	}
 	debug("Rx_done\n");

 	return i;
 }

 static void xilinx_spi_startup_block(struct udevice *dev, unsigned int bytes,
 				     const void *dout, void *din)
 {
 	struct udevice *bus = dev_get_parent(dev);
 	struct xilinx_spi_priv *priv = dev_get_priv(bus);
 	struct xilinx_spi_regs *regs = priv->regs;
 	struct dm_spi_slave_platdata *slave_plat = dev_get_parent_platdata(dev);
 	const unsigned char *txp = dout;
 	unsigned char *rxp = din;
 	u32 reg, count;
 	u32 txbytes = bytes;
 	u32 rxbytes = bytes;

 	/*
 	 * This loop runs two times. First time to send the command.
 	 * Second time to transfer data. After transferring data,
 	 * it sets txp to the initial value for the normal operation.
 	 */
 	for ( ; priv->startup < 2; priv->startup++) {
 		count = xilinx_spi_fill_txfifo(bus, txp, txbytes);
 		reg = readl(&regs->spicr) & ~SPICR_MASTER_INHIBIT;
 		writel(reg, &regs->spicr);
 		count = xilinx_spi_read_rxfifo(bus, rxp, rxbytes);
 		txp = din;

 		if (priv->startup) {
 			spi_cs_deactivate(dev);
 			spi_cs_activate(dev, slave_plat->cs);
 			txp = dout;
 		}
 	}
 }

 static int xilinx_spi_xfer(struct udevice *dev, unsigned int bitlen,
 			    const void *dout, void *din, unsigned long flags)
 {
 	struct udevice *bus = dev_get_parent(dev);
 	struct xilinx_spi_priv *priv = dev_get_priv(bus);
 	struct xilinx_spi_regs *regs = priv->regs;
 	struct dm_spi_slave_platdata *slave_plat = dev_get_parent_platdata(dev);
 	/* assume spi core configured to do 8 bit transfers */
 	unsigned int bytes = bitlen / XILSPI_MAX_XFER_BITS;
 	const unsigned char *txp = dout;
 	unsigned char *rxp = din;
 	u32 txbytes = bytes;
 	u32 rxbytes = bytes;
 	u32 reg, count, timeout;
 	int ret;

 	debug("spi_xfer: bus:%i cs:%i bitlen:%i bytes:%i flags:%lx\n",
 	      bus->seq, slave_plat->cs, bitlen, bytes, flags);

 	if (bitlen == 0)
 		goto done;

 	if (bitlen % XILSPI_MAX_XFER_BITS) {
 		printf("XILSPI warning: Not a multiple of %d bits\n",
 		       XILSPI_MAX_XFER_BITS);
 		flags |= SPI_XFER_END;
 		goto done;
 	}

 	if (flags & SPI_XFER_BEGIN)
 		spi_cs_activate(dev, slave_plat->cs);

 	/*
 	 * This is the work around for the startup block issue in
 	 * the spi controller. SPI clock is passing through STARTUP
 	 * block to FLASH. STARTUP block don't provide clock as soon
 	 * as QSPI provides command. So first command fails.
 	 */
 	xilinx_spi_startup_block(dev, bytes, dout, din);

 	while (txbytes && rxbytes) {
 		count = xilinx_spi_fill_txfifo(bus, txp, txbytes);
 		reg = readl(&regs->spicr) & ~SPICR_MASTER_INHIBIT;
 		writel(reg, &regs->spicr);
 		txbytes -= count;
 		if (txp)
 			txp += count;

 		ret = wait_for_bit_le32(&regs->spisr, SPISR_TX_EMPTY, true,
 					XILINX_SPISR_TIMEOUT, false);
 		if (ret < 0) {
 			printf("XILSPI error: Xfer timeout\n");
 			return ret;
 		}

 		debug("txbytes:0x%x,txp:0x%p\n", txbytes, txp);
 		count = xilinx_spi_read_rxfifo(bus, rxp, rxbytes);
 		rxbytes -= count;
 		if (rxp)
 			rxp += count;
 		debug("rxbytes:0x%x rxp:0x%p\n", rxbytes, rxp);
 	}

  done:
 	if (flags & SPI_XFER_END)
 		spi_cs_deactivate(dev);

 	return 0;
 }

 static int xilinx_spi_set_speed(struct udevice *bus, uint speed)
 {
 	struct xilinx_spi_priv *priv = dev_get_priv(bus);

 	priv->freq = speed;

 	debug("xilinx_spi_set_speed: regs=%p, speed=%d\n", priv->regs,
 	      priv->freq);

 	return 0;
 }

 static int xilinx_spi_set_mode(struct udevice *bus, uint mode)
 {
 	struct xilinx_spi_priv *priv = dev_get_priv(bus);
 	struct xilinx_spi_regs *regs = priv->regs;
 	uint32_t spicr;

 	spicr = readl(&regs->spicr);
 	if (mode & SPI_LSB_FIRST)
 		spicr |= SPICR_LSB_FIRST;
 	if (mode & SPI_CPHA)
 		spicr |= SPICR_CPHA;
 	if (mode & SPI_CPOL)
 		spicr |= SPICR_CPOL;
 	if (mode & SPI_LOOP)
 		spicr |= SPICR_LOOP;

 	writel(spicr, &regs->spicr);
 	priv->mode = mode;

 	debug("xilinx_spi_set_mode: regs=%p, mode=%d\n", priv->regs,
 	      priv->mode);

 	return 0;
 }

 static const struct dm_spi_ops xilinx_spi_ops = {
 	.claim_bus	= xilinx_spi_claim_bus,
 	.release_bus	= xilinx_spi_release_bus,
 	.xfer		= xilinx_spi_xfer,
 	.set_speed	= xilinx_spi_set_speed,
 	.set_mode	= xilinx_spi_set_mode,
 };

 static const struct udevice_id xilinx_spi_ids[] = {
 	{ .compatible = "xlnx,xps-spi-2.00.a" },
 	{ .compatible = "xlnx,xps-spi-2.00.b" },
 	{ }
 };

 U_BOOT_DRIVER(xilinx_spi) = {
 	.name	= "xilinx_spi",
 	.id	= UCLASS_SPI,
 	.of_match = xilinx_spi_ids,
 	.ops	= &xilinx_spi_ops,
 	.priv_auto_alloc_size = sizeof(struct xilinx_spi_priv),
 	.probe	= xilinx_spi_probe,
 };
	// SPDX-License-Identifier: GPL-2.0+
	/*
	* Xilinx SPI driver
	*
	* Supports 8 bit SPI transfers only, with or w/o FIFO
	*
	* Based on bfin_spi.c, by way of altera_spi.c
	* Copyright (c) 2015 Jagan Teki <jteki@openedev.com>
	* Copyright (c) 2012 Stephan Linz <linz@li-pro.net>
	* Copyright (c) 2010 Graeme Smecher <graeme.smecher@mail.mcgill.ca>
	* Copyright (c) 2010 Thomas Chou <thomas@wytron.com.tw>
	* Copyright (c) 2005-2008 Analog Devices Inc.
	*/

	#include <config.h>
	#include <common.h>
	#include <dm.h>
	#include <errno.h>
	#include <log.h>
	#include <malloc.h>
	#include <spi.h>
	#include <asm/io.h>
	#include <wait_bit.h>

	/*
	* [0]: http://www.xilinx.com/support/documentation
	*
	* Xilinx SPI Register Definitions
	* [1]: [0]/ip_documentation/xps_spi.pdf
	* page 8, Register Descriptions
	* [2]: [0]/ip_documentation/axi_spi_ds742.pdf
	* page 7, Register Overview Table
	*/

	/* SPI Control Register (spicr), [1] p9, [2] p8 */
	#define SPICR_LSB_FIRST BIT(9)
	#define SPICR_MASTER_INHIBIT BIT(8)
	#define SPICR_MANUAL_SS BIT(7)
	#define SPICR_RXFIFO_RESEST BIT(6)
	#define SPICR_TXFIFO_RESEST BIT(5)
	#define SPICR_CPHA BIT(4)
	#define SPICR_CPOL BIT(3)
	#define SPICR_MASTER_MODE BIT(2)
	#define SPICR_SPE BIT(1)
	#define SPICR_LOOP BIT(0)

	/* SPI Status Register (spisr), [1] p11, [2] p10 */
	#define SPISR_SLAVE_MODE_SELECT BIT(5)
	#define SPISR_MODF BIT(4)
	#define SPISR_TX_FULL BIT(3)
	#define SPISR_TX_EMPTY BIT(2)
	#define SPISR_RX_FULL BIT(1)
	#define SPISR_RX_EMPTY BIT(0)

	/* SPI Data Transmit Register (spidtr), [1] p12, [2] p12 */
	#define SPIDTR_8BIT_MASK GENMASK(7, 0)
	#define SPIDTR_16BIT_MASK GENMASK(15, 0)
	#define SPIDTR_32BIT_MASK GENMASK(31, 0)

	/* SPI Data Receive Register (spidrr), [1] p12, [2] p12 */
	#define SPIDRR_8BIT_MASK GENMASK(7, 0)
	#define SPIDRR_16BIT_MASK GENMASK(15, 0)
	#define SPIDRR_32BIT_MASK GENMASK(31, 0)

	/* SPI Slave Select Register (spissr), [1] p13, [2] p13 */
	#define SPISSR_MASK(cs) (1 << (cs))
	#define SPISSR_ACT(cs) ~SPISSR_MASK(cs)
	#define SPISSR_OFF ~0UL

	/* SPI Software Reset Register (ssr) */
	#define SPISSR_RESET_VALUE 0x0a

	#define XILSPI_MAX_XFER_BITS 8
	#define XILSPI_SPICR_DFLT_ON (SPICR_MANUAL_SS \| SPICR_MASTER_MODE \| \
	SPICR_SPE)
	#define XILSPI_SPICR_DFLT_OFF (SPICR_MASTER_INHIBIT \| SPICR_MANUAL_SS)

	#ifndef CONFIG_XILINX_SPI_IDLE_VAL
	#define CONFIG_XILINX_SPI_IDLE_VAL GENMASK(7, 0)
	#endif

	#define XILINX_SPISR_TIMEOUT 10000 /* in milliseconds */

	/* xilinx spi register set */
	struct xilinx_spi_regs {
	u32 __space0__[7];
	u32 dgier; /* Device Global Interrupt Enable Register (DGIER) */
	u32 ipisr; /* IP Interrupt Status Register (IPISR) */
	u32 __space1__;
	u32 ipier; /* IP Interrupt Enable Register (IPIER) */
	u32 __space2__[5];
	u32 srr; /* Softare Reset Register (SRR) */
	u32 __space3__[7];
	u32 spicr; /* SPI Control Register (SPICR) */
	u32 spisr; /* SPI Status Register (SPISR) */
	u32 spidtr; /* SPI Data Transmit Register (SPIDTR) */
	u32 spidrr; /* SPI Data Receive Register (SPIDRR) */
	u32 spissr; /* SPI Slave Select Register (SPISSR) */
	u32 spitfor; /* SPI Transmit FIFO Occupancy Register (SPITFOR) */
	u32 spirfor; /* SPI Receive FIFO Occupancy Register (SPIRFOR) */
	};

	/* xilinx spi priv */
	struct xilinx_spi_priv {
	struct xilinx_spi_regs *regs;
	unsigned int freq;
	unsigned int mode;
	unsigned int fifo_depth;
	u8 startup;
	};

	static int xilinx_spi_probe(struct udevice *bus)
	{
	struct xilinx_spi_priv *priv = dev_get_priv(bus);
	struct xilinx_spi_regs *regs = priv->regs;

	priv->regs = (struct xilinx_spi_regs *)dev_read_addr(bus);

	priv->fifo_depth = dev_read_u32_default(bus, "fifo-size", 0);

	writel(SPISSR_RESET_VALUE, &regs->srr);

	return 0;
	}

	static void spi_cs_activate(struct udevice *dev, uint cs)
	{
	struct udevice *bus = dev_get_parent(dev);
	struct xilinx_spi_priv *priv = dev_get_priv(bus);
	struct xilinx_spi_regs *regs = priv->regs;

	writel(SPISSR_ACT(cs), &regs->spissr);
	}

	static void spi_cs_deactivate(struct udevice *dev)
	{
	struct udevice *bus = dev_get_parent(dev);
	struct xilinx_spi_priv *priv = dev_get_priv(bus);
	struct xilinx_spi_regs *regs = priv->regs;

	writel(SPISSR_OFF, &regs->spissr);
	}

	static int xilinx_spi_claim_bus(struct udevice *dev)
	{
	struct udevice *bus = dev_get_parent(dev);
	struct xilinx_spi_priv *priv = dev_get_priv(bus);
	struct xilinx_spi_regs *regs = priv->regs;

	writel(SPISSR_OFF, &regs->spissr);
	writel(XILSPI_SPICR_DFLT_ON, &regs->spicr);

	return 0;
	}

	static int xilinx_spi_release_bus(struct udevice *dev)
	{
	struct udevice *bus = dev_get_parent(dev);
	struct xilinx_spi_priv *priv = dev_get_priv(bus);
	struct xilinx_spi_regs *regs = priv->regs;

	writel(SPISSR_OFF, &regs->spissr);
	writel(XILSPI_SPICR_DFLT_OFF, &regs->spicr);

	return 0;
	}

	static u32 xilinx_spi_fill_txfifo(struct udevice bus, const u8 txp,
	u32 txbytes)
	{
	struct xilinx_spi_priv *priv = dev_get_priv(bus);
	struct xilinx_spi_regs *regs = priv->regs;
	unsigned char d;
	u32 i = 0;

	while (txbytes && !(readl(&regs->spisr) & SPISR_TX_FULL) &&
	i < priv->fifo_depth) {
	d = txp ? *txp++ : CONFIG_XILINX_SPI_IDLE_VAL;
	debug("spi_xfer: tx:%x ", d);
	/* write out and wait for processing (receive data) */
	writel(d & SPIDTR_8BIT_MASK, &regs->spidtr);
	txbytes--;
	i++;
	}

	return i;
	}

	static u32 xilinx_spi_read_rxfifo(struct udevice bus, u8 rxp, u32 rxbytes)
	{
	struct xilinx_spi_priv *priv = dev_get_priv(bus);
	struct xilinx_spi_regs *regs = priv->regs;
	unsigned char d;
	unsigned int i = 0;

	while (rxbytes && !(readl(&regs->spisr) & SPISR_RX_EMPTY)) {
	d = readl(&regs->spidrr) & SPIDRR_8BIT_MASK;
	if (rxp)
	*rxp++ = d;
	debug("spi_xfer: rx:%x\n", d);
	rxbytes--;
	i++;
	}
	debug("Rx_done\n");

	return i;
	}

	static void xilinx_spi_startup_block(struct udevice *dev, unsigned int bytes,
	const void dout, void din)
	{
	struct udevice *bus = dev_get_parent(dev);
	struct xilinx_spi_priv *priv = dev_get_priv(bus);
	struct xilinx_spi_regs *regs = priv->regs;
	struct dm_spi_slave_platdata *slave_plat = dev_get_parent_platdata(dev);
	const unsigned char *txp = dout;
	unsigned char *rxp = din;
	u32 reg, count;
	u32 txbytes = bytes;
	u32 rxbytes = bytes;

	/*
	* This loop runs two times. First time to send the command.
	* Second time to transfer data. After transferring data,
	* it sets txp to the initial value for the normal operation.
	*/
	for ( ; priv->startup < 2; priv->startup++) {
	count = xilinx_spi_fill_txfifo(bus, txp, txbytes);
	reg = readl(&regs->spicr) & ~SPICR_MASTER_INHIBIT;
	writel(reg, &regs->spicr);
	count = xilinx_spi_read_rxfifo(bus, rxp, rxbytes);
	txp = din;

	if (priv->startup) {
	spi_cs_deactivate(dev);
	spi_cs_activate(dev, slave_plat->cs);
	txp = dout;
	}
	}
	}

	static int xilinx_spi_xfer(struct udevice *dev, unsigned int bitlen,
	const void dout, void din, unsigned long flags)
	{
	struct udevice *bus = dev_get_parent(dev);
	struct xilinx_spi_priv *priv = dev_get_priv(bus);
	struct xilinx_spi_regs *regs = priv->regs;
	struct dm_spi_slave_platdata *slave_plat = dev_get_parent_platdata(dev);
	/* assume spi core configured to do 8 bit transfers */
	unsigned int bytes = bitlen / XILSPI_MAX_XFER_BITS;
	const unsigned char *txp = dout;
	unsigned char *rxp = din;
	u32 txbytes = bytes;
	u32 rxbytes = bytes;
	u32 reg, count, timeout;
	int ret;

	debug("spi_xfer: bus:%i cs:%i bitlen:%i bytes:%i flags:%lx\n",
	bus->seq, slave_plat->cs, bitlen, bytes, flags);

	if (bitlen == 0)
	goto done;

	if (bitlen % XILSPI_MAX_XFER_BITS) {
	printf("XILSPI warning: Not a multiple of %d bits\n",
	XILSPI_MAX_XFER_BITS);
	flags \|= SPI_XFER_END;
	goto done;
	}

	if (flags & SPI_XFER_BEGIN)
	spi_cs_activate(dev, slave_plat->cs);

	/*
	* This is the work around for the startup block issue in
	* the spi controller. SPI clock is passing through STARTUP
	* block to FLASH. STARTUP block don't provide clock as soon
	* as QSPI provides command. So first command fails.
	*/
	xilinx_spi_startup_block(dev, bytes, dout, din);

	while (txbytes && rxbytes) {
	count = xilinx_spi_fill_txfifo(bus, txp, txbytes);
	reg = readl(&regs->spicr) & ~SPICR_MASTER_INHIBIT;
	writel(reg, &regs->spicr);
	txbytes -= count;
	if (txp)
	txp += count;

	ret = wait_for_bit_le32(&regs->spisr, SPISR_TX_EMPTY, true,
	XILINX_SPISR_TIMEOUT, false);
	if (ret < 0) {
	printf("XILSPI error: Xfer timeout\n");
	return ret;
	}

	debug("txbytes:0x%x,txp:0x%p\n", txbytes, txp);
	count = xilinx_spi_read_rxfifo(bus, rxp, rxbytes);
	rxbytes -= count;
	if (rxp)
	rxp += count;
	debug("rxbytes:0x%x rxp:0x%p\n", rxbytes, rxp);
	}

	done:
	if (flags & SPI_XFER_END)
	spi_cs_deactivate(dev);

	return 0;
	}

	static int xilinx_spi_set_speed(struct udevice *bus, uint speed)
	{
	struct xilinx_spi_priv *priv = dev_get_priv(bus);

	priv->freq = speed;

	debug("xilinx_spi_set_speed: regs=%p, speed=%d\n", priv->regs,
	priv->freq);

	return 0;
	}

	static int xilinx_spi_set_mode(struct udevice *bus, uint mode)
	{
	struct xilinx_spi_priv *priv = dev_get_priv(bus);
	struct xilinx_spi_regs *regs = priv->regs;
	uint32_t spicr;

	spicr = readl(&regs->spicr);
	if (mode & SPI_LSB_FIRST)
	spicr \|= SPICR_LSB_FIRST;
	if (mode & SPI_CPHA)
	spicr \|= SPICR_CPHA;
	if (mode & SPI_CPOL)
	spicr \|= SPICR_CPOL;
	if (mode & SPI_LOOP)
	spicr \|= SPICR_LOOP;

	writel(spicr, &regs->spicr);
	priv->mode = mode;

	debug("xilinx_spi_set_mode: regs=%p, mode=%d\n", priv->regs,
	priv->mode);

	return 0;
	}

	static const struct dm_spi_ops xilinx_spi_ops = {
	.claim_bus = xilinx_spi_claim_bus,
	.release_bus = xilinx_spi_release_bus,
	.xfer = xilinx_spi_xfer,
	.set_speed = xilinx_spi_set_speed,
	.set_mode = xilinx_spi_set_mode,
	};

	static const struct udevice_id xilinx_spi_ids[] = {
	{ .compatible = "xlnx,xps-spi-2.00.a" },
	{ .compatible = "xlnx,xps-spi-2.00.b" },
	{ }
	};

	U_BOOT_DRIVER(xilinx_spi) = {
	.name = "xilinx_spi",
	.id = UCLASS_SPI,
	.of_match = xilinx_spi_ids,
	.ops = &xilinx_spi_ops,
	.priv_auto_alloc_size = sizeof(struct xilinx_spi_priv),
	.probe = xilinx_spi_probe,
	};