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

 // SPDX-License-Identifier: GPL-2.0+
 /*
  * Copyright (C) 2012
  * Altera Corporation <www.altera.com>
  */

 #include <common.h>
 #include <clk.h>
 #include <log.h>
 #include <asm-generic/io.h>
 #include <dm.h>
 #include <fdtdec.h>
 #include <malloc.h>
 #include <reset.h>
 #include <spi.h>
 #include <spi-mem.h>
 #include <dm/device_compat.h>
 #include <linux/err.h>
 #include <linux/errno.h>
 #include <linux/sizes.h>
 #include "cadence_qspi.h"

 #define NSEC_PER_SEC			1000000000L

 #define CQSPI_STIG_READ			0
 #define CQSPI_STIG_WRITE		1
 #define CQSPI_READ			2
 #define CQSPI_WRITE			3

 static int cadence_spi_write_speed(struct udevice *bus, uint hz)
 {
 	struct cadence_spi_plat *plat = dev_get_plat(bus);
 	struct cadence_spi_priv *priv = dev_get_priv(bus);

 	cadence_qspi_apb_config_baudrate_div(priv->regbase,
 					     plat->ref_clk_hz, hz);

 	/* Reconfigure delay timing if speed is changed. */
 	cadence_qspi_apb_delay(priv->regbase, plat->ref_clk_hz, hz,
 			       plat->tshsl_ns, plat->tsd2d_ns,
 			       plat->tchsh_ns, plat->tslch_ns);

 	return 0;
 }

 static int cadence_spi_read_id(struct cadence_spi_plat *plat, u8 len,
 			       u8 *idcode)
 {
 	struct spi_mem_op op = SPI_MEM_OP(SPI_MEM_OP_CMD(0x9F, 1),
 					  SPI_MEM_OP_NO_ADDR,
 					  SPI_MEM_OP_NO_DUMMY,
 					  SPI_MEM_OP_DATA_IN(len, idcode, 1));

 	return cadence_qspi_apb_command_read(plat, &op);
 }

 /* Calibration sequence to determine the read data capture delay register */
 static int spi_calibration(struct udevice *bus, uint hz)
 {
 	struct cadence_spi_priv *priv = dev_get_priv(bus);
 	struct cadence_spi_plat *plat = dev_get_plat(bus);
 	void *base = priv->regbase;
 	unsigned int idcode = 0, temp = 0;
 	int err = 0, i, range_lo = -1, range_hi = -1;

 	/* start with slowest clock (1 MHz) */
 	cadence_spi_write_speed(bus, 1000000);

 	/* configure the read data capture delay register to 0 */
 	cadence_qspi_apb_readdata_capture(base, 1, 0);

 	/* Enable QSPI */
 	cadence_qspi_apb_controller_enable(base);

 	/* read the ID which will be our golden value */
 	err = cadence_spi_read_id(plat, 3, (u8 *)&idcode);
 	if (err) {
 		puts("SF: Calibration failed (read)\n");
 		return err;
 	}

 	/* use back the intended clock and find low range */
 	cadence_spi_write_speed(bus, hz);
 	for (i = 0; i < CQSPI_READ_CAPTURE_MAX_DELAY; i++) {
 		/* Disable QSPI */
 		cadence_qspi_apb_controller_disable(base);

 		/* reconfigure the read data capture delay register */
 		cadence_qspi_apb_readdata_capture(base, 1, i);

 		/* Enable back QSPI */
 		cadence_qspi_apb_controller_enable(base);

 		/* issue a RDID to get the ID value */
 		err = cadence_spi_read_id(plat, 3, (u8 *)&temp);
 		if (err) {
 			puts("SF: Calibration failed (read)\n");
 			return err;
 		}

 		/* search for range lo */
 		if (range_lo == -1 && temp == idcode) {
 			range_lo = i;
 			continue;
 		}

 		/* search for range hi */
 		if (range_lo != -1 && temp != idcode) {
 			range_hi = i - 1;
 			break;
 		}
 		range_hi = i;
 	}

 	if (range_lo == -1) {
 		puts("SF: Calibration failed (low range)\n");
 		return err;
 	}

 	/* Disable QSPI for subsequent initialization */
 	cadence_qspi_apb_controller_disable(base);

 	/* configure the final value for read data capture delay register */
 	cadence_qspi_apb_readdata_capture(base, 1, (range_hi + range_lo) / 2);
 	debug("SF: Read data capture delay calibrated to %i (%i - %i)\n",
 	      (range_hi + range_lo) / 2, range_lo, range_hi);

 	/* just to ensure we do once only when speed or chip select change */
 	priv->qspi_calibrated_hz = hz;
 	priv->qspi_calibrated_cs = spi_chip_select(bus);

 	return 0;
 }

 static int cadence_spi_set_speed(struct udevice *bus, uint hz)
 {
 	struct cadence_spi_plat *plat = dev_get_plat(bus);
 	struct cadence_spi_priv *priv = dev_get_priv(bus);
 	int err;

 	if (hz > plat->max_hz)
 		hz = plat->max_hz;

 	/* Disable QSPI */
 	cadence_qspi_apb_controller_disable(priv->regbase);

 	/*
 	 * If the device tree already provides a read delay value, use that
 	 * instead of calibrating.
 	 */
 	if (plat->read_delay >= 0) {
 		cadence_spi_write_speed(bus, hz);
 		cadence_qspi_apb_readdata_capture(priv->regbase, 1,
 						  plat->read_delay);
 	} else if (priv->previous_hz != hz ||
 		   priv->qspi_calibrated_hz != hz ||
 		   priv->qspi_calibrated_cs != spi_chip_select(bus)) {
 		/*
 		 * Calibration required for different current SCLK speed,
 		 * requested SCLK speed or chip select
 		 */
 		err = spi_calibration(bus, hz);
 		if (err)
 			return err;

 		/* prevent calibration run when same as previous request */
 		priv->previous_hz = hz;
 	}

 	/* Enable QSPI */
 	cadence_qspi_apb_controller_enable(priv->regbase);

 	debug("%s: speed=%d\n", __func__, hz);

 	return 0;
 }

 static int cadence_spi_probe(struct udevice *bus)
 {
 	struct cadence_spi_plat *plat = dev_get_plat(bus);
 	struct cadence_spi_priv *priv = dev_get_priv(bus);
 	struct clk clk;
 	int ret;

 	priv->regbase = plat->regbase;
 	priv->ahbbase = plat->ahbbase;

 	if (plat->ref_clk_hz == 0) {
 		ret = clk_get_by_index(bus, 0, &clk);
 		if (ret) {
 #ifdef CONFIG_CQSPI_REF_CLK
 			plat->ref_clk_hz = CONFIG_CQSPI_REF_CLK;
 #else
 			return ret;
 #endif
 		} else {
 			plat->ref_clk_hz = clk_get_rate(&clk);
 			clk_free(&clk);
 			if (IS_ERR_VALUE(plat->ref_clk_hz))
 				return plat->ref_clk_hz;
 		}
 	}

 	ret = reset_get_bulk(bus, &priv->resets);
 	if (ret)
 		dev_warn(bus, "Can't get reset: %d\n", ret);
 	else
 		reset_deassert_bulk(&priv->resets);

 	if (!priv->qspi_is_init) {
 		cadence_qspi_apb_controller_init(plat);
 		priv->qspi_is_init = 1;
 	}

 	plat->wr_delay = 50 * DIV_ROUND_UP(NSEC_PER_SEC, plat->ref_clk_hz);

 	return 0;
 }

 static int cadence_spi_remove(struct udevice *dev)
 {
 	struct cadence_spi_priv *priv = dev_get_priv(dev);

 	return reset_release_bulk(&priv->resets);
 }

 static int cadence_spi_set_mode(struct udevice *bus, uint mode)
 {
 	struct cadence_spi_plat *plat = dev_get_plat(bus);
 	struct cadence_spi_priv *priv = dev_get_priv(bus);

 	/* Disable QSPI */
 	cadence_qspi_apb_controller_disable(priv->regbase);

 	/* Set SPI mode */
 	cadence_qspi_apb_set_clk_mode(priv->regbase, mode);

 	/* Enable Direct Access Controller */
 	if (plat->use_dac_mode)
 		cadence_qspi_apb_dac_mode_enable(priv->regbase);

 	/* Enable QSPI */
 	cadence_qspi_apb_controller_enable(priv->regbase);

 	return 0;
 }

 static int cadence_spi_mem_exec_op(struct spi_slave *spi,
 				   const struct spi_mem_op *op)
 {
 	struct udevice *bus = spi->dev->parent;
 	struct cadence_spi_plat *plat = dev_get_plat(bus);
 	struct cadence_spi_priv *priv = dev_get_priv(bus);
 	void *base = priv->regbase;
 	int err = 0;
 	u32 mode;

 	/* Set Chip select */
 	cadence_qspi_apb_chipselect(base, spi_chip_select(spi->dev),
 				    plat->is_decoded_cs);

 	if (op->data.dir == SPI_MEM_DATA_IN && op->data.buf.in) {
 		if (!op->addr.nbytes)
 			mode = CQSPI_STIG_READ;
 		else
 			mode = CQSPI_READ;
 	} else {
 		if (!op->addr.nbytes || !op->data.buf.out)
 			mode = CQSPI_STIG_WRITE;
 		else
 			mode = CQSPI_WRITE;
 	}

 	switch (mode) {
 	case CQSPI_STIG_READ:
 		err = cadence_qspi_apb_command_read_setup(plat, op);
 		if (!err)
 			err = cadence_qspi_apb_command_read(plat, op);
 		break;
 	case CQSPI_STIG_WRITE:
 		err = cadence_qspi_apb_command_write_setup(plat, op);
 		if (!err)
 			err = cadence_qspi_apb_command_write(plat, op);
 		break;
 	case CQSPI_READ:
 		err = cadence_qspi_apb_read_setup(plat, op);
 		if (!err)
 			err = cadence_qspi_apb_read_execute(plat, op);
 		break;
 	case CQSPI_WRITE:
 		err = cadence_qspi_apb_write_setup(plat, op);
 		if (!err)
 			err = cadence_qspi_apb_write_execute(plat, op);
 		break;
 	default:
 		err = -1;
 		break;
 	}

 	return err;
 }

 static bool cadence_spi_mem_supports_op(struct spi_slave *slave,
 					const struct spi_mem_op *op)
 {
 	bool all_true, all_false;

 	all_true = op->cmd.dtr && op->addr.dtr && op->dummy.dtr &&
 		   op->data.dtr;
 	all_false = !op->cmd.dtr && !op->addr.dtr && !op->dummy.dtr &&
 		    !op->data.dtr;

 	/* Mixed DTR modes not supported. */
 	if (!(all_true || all_false))
 		return false;

 	if (all_true)
 		return spi_mem_dtr_supports_op(slave, op);
 	else
 		return spi_mem_default_supports_op(slave, op);
 }

 static int cadence_spi_of_to_plat(struct udevice *bus)
 {
 	struct cadence_spi_plat *plat = dev_get_plat(bus);
 	ofnode subnode;

 	plat->regbase = (void *)devfdt_get_addr_index(bus, 0);
 	plat->ahbbase = (void *)devfdt_get_addr_size_index(bus, 1,
 			&plat->ahbsize);
 	plat->is_decoded_cs = dev_read_bool(bus, "cdns,is-decoded-cs");
 	plat->fifo_depth = dev_read_u32_default(bus, "cdns,fifo-depth", 128);
 	plat->fifo_width = dev_read_u32_default(bus, "cdns,fifo-width", 4);
 	plat->trigger_address = dev_read_u32_default(bus,
 						     "cdns,trigger-address",
 						     0);
 	/* Use DAC mode only when MMIO window is at least 8M wide */
 	if (plat->ahbsize >= SZ_8M)
 		plat->use_dac_mode = true;

 	/* All other paramters are embedded in the child node */
 	subnode = dev_read_first_subnode(bus);
 	if (!ofnode_valid(subnode)) {
 		printf("Error: subnode with SPI flash config missing!\n");
 		return -ENODEV;
 	}

 	/* Use 500 KHz as a suitable default */
 	plat->max_hz = ofnode_read_u32_default(subnode, "spi-max-frequency",
 					       500000);

 	/* Read other parameters from DT */
 	plat->page_size = ofnode_read_u32_default(subnode, "page-size", 256);
 	plat->block_size = ofnode_read_u32_default(subnode, "block-size", 16);
 	plat->tshsl_ns = ofnode_read_u32_default(subnode, "cdns,tshsl-ns",
 						 200);
 	plat->tsd2d_ns = ofnode_read_u32_default(subnode, "cdns,tsd2d-ns",
 						 255);
 	plat->tchsh_ns = ofnode_read_u32_default(subnode, "cdns,tchsh-ns", 20);
 	plat->tslch_ns = ofnode_read_u32_default(subnode, "cdns,tslch-ns", 20);
 	/*
 	 * Read delay should be an unsigned value but we use a signed integer
 	 * so that negative values can indicate that the device tree did not
 	 * specify any signed values and we need to perform the calibration
 	 * sequence to find it out.
 	 */
 	plat->read_delay = ofnode_read_s32_default(subnode, "cdns,read-delay",
 						   -1);

 	debug("%s: regbase=%p ahbbase=%p max-frequency=%d page-size=%d\n",
 	      __func__, plat->regbase, plat->ahbbase, plat->max_hz,
 	      plat->page_size);

 	return 0;
 }

 static const struct spi_controller_mem_ops cadence_spi_mem_ops = {
 	.exec_op = cadence_spi_mem_exec_op,
 	.supports_op = cadence_spi_mem_supports_op,
 };

 static const struct dm_spi_ops cadence_spi_ops = {
 	.set_speed	= cadence_spi_set_speed,
 	.set_mode	= cadence_spi_set_mode,
 	.mem_ops	= &cadence_spi_mem_ops,
 	/*
 	 * cs_info is not needed, since we require all chip selects to be
 	 * in the device tree explicitly
 	 */
 };

 static const struct udevice_id cadence_spi_ids[] = {
 	{ .compatible = "cdns,qspi-nor" },
 	{ .compatible = "ti,am654-ospi" },
 	{ }
 };

 U_BOOT_DRIVER(cadence_spi) = {
 	.name = "cadence_spi",
 	.id = UCLASS_SPI,
 	.of_match = cadence_spi_ids,
 	.ops = &cadence_spi_ops,
 	.of_to_plat = cadence_spi_of_to_plat,
 	.plat_auto	= sizeof(struct cadence_spi_plat),
 	.priv_auto	= sizeof(struct cadence_spi_priv),
 	.probe = cadence_spi_probe,
 	.remove = cadence_spi_remove,
 	.flags = DM_FLAG_OS_PREPARE,
 };
	// SPDX-License-Identifier: GPL-2.0+
	/*
	* Copyright (C) 2012
	* Altera Corporation <www.altera.com>
	*/

	#include <common.h>
	#include <clk.h>
	#include <log.h>
	#include <asm-generic/io.h>
	#include <dm.h>
	#include <fdtdec.h>
	#include <malloc.h>
	#include <reset.h>
	#include <spi.h>
	#include <spi-mem.h>
	#include <dm/device_compat.h>
	#include <linux/err.h>
	#include <linux/errno.h>
	#include <linux/sizes.h>
	#include "cadence_qspi.h"

	#define NSEC_PER_SEC 1000000000L

	#define CQSPI_STIG_READ 0
	#define CQSPI_STIG_WRITE 1
	#define CQSPI_READ 2
	#define CQSPI_WRITE 3

	static int cadence_spi_write_speed(struct udevice *bus, uint hz)
	{
	struct cadence_spi_plat *plat = dev_get_plat(bus);
	struct cadence_spi_priv *priv = dev_get_priv(bus);

	cadence_qspi_apb_config_baudrate_div(priv->regbase,
	plat->ref_clk_hz, hz);

	/* Reconfigure delay timing if speed is changed. */
	cadence_qspi_apb_delay(priv->regbase, plat->ref_clk_hz, hz,
	plat->tshsl_ns, plat->tsd2d_ns,
	plat->tchsh_ns, plat->tslch_ns);

	return 0;
	}

	static int cadence_spi_read_id(struct cadence_spi_plat *plat, u8 len,
	u8 *idcode)
	{
	struct spi_mem_op op = SPI_MEM_OP(SPI_MEM_OP_CMD(0x9F, 1),
	SPI_MEM_OP_NO_ADDR,
	SPI_MEM_OP_NO_DUMMY,
	SPI_MEM_OP_DATA_IN(len, idcode, 1));

	return cadence_qspi_apb_command_read(plat, &op);
	}

	/* Calibration sequence to determine the read data capture delay register */
	static int spi_calibration(struct udevice *bus, uint hz)
	{
	struct cadence_spi_priv *priv = dev_get_priv(bus);
	struct cadence_spi_plat *plat = dev_get_plat(bus);
	void *base = priv->regbase;
	unsigned int idcode = 0, temp = 0;
	int err = 0, i, range_lo = -1, range_hi = -1;

	/* start with slowest clock (1 MHz) */
	cadence_spi_write_speed(bus, 1000000);

	/* configure the read data capture delay register to 0 */
	cadence_qspi_apb_readdata_capture(base, 1, 0);

	/* Enable QSPI */
	cadence_qspi_apb_controller_enable(base);

	/* read the ID which will be our golden value */
	err = cadence_spi_read_id(plat, 3, (u8 *)&idcode);
	if (err) {
	puts("SF: Calibration failed (read)\n");
	return err;
	}

	/* use back the intended clock and find low range */
	cadence_spi_write_speed(bus, hz);
	for (i = 0; i < CQSPI_READ_CAPTURE_MAX_DELAY; i++) {
	/* Disable QSPI */
	cadence_qspi_apb_controller_disable(base);

	/* reconfigure the read data capture delay register */
	cadence_qspi_apb_readdata_capture(base, 1, i);

	/* Enable back QSPI */
	cadence_qspi_apb_controller_enable(base);

	/* issue a RDID to get the ID value */
	err = cadence_spi_read_id(plat, 3, (u8 *)&temp);
	if (err) {
	puts("SF: Calibration failed (read)\n");
	return err;
	}

	/* search for range lo */
	if (range_lo == -1 && temp == idcode) {
	range_lo = i;
	continue;
	}

	/* search for range hi */
	if (range_lo != -1 && temp != idcode) {
	range_hi = i - 1;
	break;
	}
	range_hi = i;
	}

	if (range_lo == -1) {
	puts("SF: Calibration failed (low range)\n");
	return err;
	}

	/* Disable QSPI for subsequent initialization */
	cadence_qspi_apb_controller_disable(base);

	/* configure the final value for read data capture delay register */
	cadence_qspi_apb_readdata_capture(base, 1, (range_hi + range_lo) / 2);
	debug("SF: Read data capture delay calibrated to %i (%i - %i)\n",
	(range_hi + range_lo) / 2, range_lo, range_hi);

	/* just to ensure we do once only when speed or chip select change */
	priv->qspi_calibrated_hz = hz;
	priv->qspi_calibrated_cs = spi_chip_select(bus);

	return 0;
	}

	static int cadence_spi_set_speed(struct udevice *bus, uint hz)
	{
	struct cadence_spi_plat *plat = dev_get_plat(bus);
	struct cadence_spi_priv *priv = dev_get_priv(bus);
	int err;

	if (hz > plat->max_hz)
	hz = plat->max_hz;

	/* Disable QSPI */
	cadence_qspi_apb_controller_disable(priv->regbase);

	/*
	* If the device tree already provides a read delay value, use that
	* instead of calibrating.
	*/
	if (plat->read_delay >= 0) {
	cadence_spi_write_speed(bus, hz);
	cadence_qspi_apb_readdata_capture(priv->regbase, 1,
	plat->read_delay);
	} else if (priv->previous_hz != hz \|\|
	priv->qspi_calibrated_hz != hz \|\|
	priv->qspi_calibrated_cs != spi_chip_select(bus)) {
	/*
	* Calibration required for different current SCLK speed,
	* requested SCLK speed or chip select
	*/
	err = spi_calibration(bus, hz);
	if (err)
	return err;

	/* prevent calibration run when same as previous request */
	priv->previous_hz = hz;
	}

	/* Enable QSPI */
	cadence_qspi_apb_controller_enable(priv->regbase);

	debug("%s: speed=%d\n", __func__, hz);

	return 0;
	}

	static int cadence_spi_probe(struct udevice *bus)
	{
	struct cadence_spi_plat *plat = dev_get_plat(bus);
	struct cadence_spi_priv *priv = dev_get_priv(bus);
	struct clk clk;
	int ret;

	priv->regbase = plat->regbase;
	priv->ahbbase = plat->ahbbase;

	if (plat->ref_clk_hz == 0) {
	ret = clk_get_by_index(bus, 0, &clk);
	if (ret) {
	#ifdef CONFIG_CQSPI_REF_CLK
	plat->ref_clk_hz = CONFIG_CQSPI_REF_CLK;
	#else
	return ret;
	#endif
	} else {
	plat->ref_clk_hz = clk_get_rate(&clk);
	clk_free(&clk);
	if (IS_ERR_VALUE(plat->ref_clk_hz))
	return plat->ref_clk_hz;
	}
	}

	ret = reset_get_bulk(bus, &priv->resets);
	if (ret)
	dev_warn(bus, "Can't get reset: %d\n", ret);
	else
	reset_deassert_bulk(&priv->resets);

	if (!priv->qspi_is_init) {
	cadence_qspi_apb_controller_init(plat);
	priv->qspi_is_init = 1;
	}

	plat->wr_delay = 50 * DIV_ROUND_UP(NSEC_PER_SEC, plat->ref_clk_hz);

	return 0;
	}

	static int cadence_spi_remove(struct udevice *dev)
	{
	struct cadence_spi_priv *priv = dev_get_priv(dev);

	return reset_release_bulk(&priv->resets);
	}

	static int cadence_spi_set_mode(struct udevice *bus, uint mode)
	{
	struct cadence_spi_plat *plat = dev_get_plat(bus);
	struct cadence_spi_priv *priv = dev_get_priv(bus);

	/* Disable QSPI */
	cadence_qspi_apb_controller_disable(priv->regbase);

	/* Set SPI mode */
	cadence_qspi_apb_set_clk_mode(priv->regbase, mode);

	/* Enable Direct Access Controller */
	if (plat->use_dac_mode)
	cadence_qspi_apb_dac_mode_enable(priv->regbase);

	/* Enable QSPI */
	cadence_qspi_apb_controller_enable(priv->regbase);

	return 0;
	}

	static int cadence_spi_mem_exec_op(struct spi_slave *spi,
	const struct spi_mem_op *op)
	{
	struct udevice *bus = spi->dev->parent;
	struct cadence_spi_plat *plat = dev_get_plat(bus);
	struct cadence_spi_priv *priv = dev_get_priv(bus);
	void *base = priv->regbase;
	int err = 0;
	u32 mode;

	/* Set Chip select */
	cadence_qspi_apb_chipselect(base, spi_chip_select(spi->dev),
	plat->is_decoded_cs);

	if (op->data.dir == SPI_MEM_DATA_IN && op->data.buf.in) {
	if (!op->addr.nbytes)
	mode = CQSPI_STIG_READ;
	else
	mode = CQSPI_READ;
	} else {
	if (!op->addr.nbytes \|\| !op->data.buf.out)
	mode = CQSPI_STIG_WRITE;
	else
	mode = CQSPI_WRITE;
	}

	switch (mode) {
	case CQSPI_STIG_READ:
	err = cadence_qspi_apb_command_read_setup(plat, op);
	if (!err)
	err = cadence_qspi_apb_command_read(plat, op);
	break;
	case CQSPI_STIG_WRITE:
	err = cadence_qspi_apb_command_write_setup(plat, op);
	if (!err)
	err = cadence_qspi_apb_command_write(plat, op);
	break;
	case CQSPI_READ:
	err = cadence_qspi_apb_read_setup(plat, op);
	if (!err)
	err = cadence_qspi_apb_read_execute(plat, op);
	break;
	case CQSPI_WRITE:
	err = cadence_qspi_apb_write_setup(plat, op);
	if (!err)
	err = cadence_qspi_apb_write_execute(plat, op);
	break;
	default:
	err = -1;
	break;
	}

	return err;
	}

	static bool cadence_spi_mem_supports_op(struct spi_slave *slave,
	const struct spi_mem_op *op)
	{
	bool all_true, all_false;

	all_true = op->cmd.dtr && op->addr.dtr && op->dummy.dtr &&
	op->data.dtr;
	all_false = !op->cmd.dtr && !op->addr.dtr && !op->dummy.dtr &&
	!op->data.dtr;

	/* Mixed DTR modes not supported. */
	if (!(all_true \|\| all_false))
	return false;

	if (all_true)
	return spi_mem_dtr_supports_op(slave, op);
	else
	return spi_mem_default_supports_op(slave, op);
	}

	static int cadence_spi_of_to_plat(struct udevice *bus)
	{
	struct cadence_spi_plat *plat = dev_get_plat(bus);
	ofnode subnode;

	plat->regbase = (void *)devfdt_get_addr_index(bus, 0);
	plat->ahbbase = (void *)devfdt_get_addr_size_index(bus, 1,
	&plat->ahbsize);
	plat->is_decoded_cs = dev_read_bool(bus, "cdns,is-decoded-cs");
	plat->fifo_depth = dev_read_u32_default(bus, "cdns,fifo-depth", 128);
	plat->fifo_width = dev_read_u32_default(bus, "cdns,fifo-width", 4);
	plat->trigger_address = dev_read_u32_default(bus,
	"cdns,trigger-address",
	0);
	/* Use DAC mode only when MMIO window is at least 8M wide */
	if (plat->ahbsize >= SZ_8M)
	plat->use_dac_mode = true;

	/* All other paramters are embedded in the child node */
	subnode = dev_read_first_subnode(bus);
	if (!ofnode_valid(subnode)) {
	printf("Error: subnode with SPI flash config missing!\n");
	return -ENODEV;
	}

	/* Use 500 KHz as a suitable default */
	plat->max_hz = ofnode_read_u32_default(subnode, "spi-max-frequency",
	500000);

	/* Read other parameters from DT */
	plat->page_size = ofnode_read_u32_default(subnode, "page-size", 256);
	plat->block_size = ofnode_read_u32_default(subnode, "block-size", 16);
	plat->tshsl_ns = ofnode_read_u32_default(subnode, "cdns,tshsl-ns",
	200);
	plat->tsd2d_ns = ofnode_read_u32_default(subnode, "cdns,tsd2d-ns",
	255);
	plat->tchsh_ns = ofnode_read_u32_default(subnode, "cdns,tchsh-ns", 20);
	plat->tslch_ns = ofnode_read_u32_default(subnode, "cdns,tslch-ns", 20);
	/*
	* Read delay should be an unsigned value but we use a signed integer
	* so that negative values can indicate that the device tree did not
	* specify any signed values and we need to perform the calibration
	* sequence to find it out.
	*/
	plat->read_delay = ofnode_read_s32_default(subnode, "cdns,read-delay",
	-1);

	debug("%s: regbase=%p ahbbase=%p max-frequency=%d page-size=%d\n",
	__func__, plat->regbase, plat->ahbbase, plat->max_hz,
	plat->page_size);

	return 0;
	}

	static const struct spi_controller_mem_ops cadence_spi_mem_ops = {
	.exec_op = cadence_spi_mem_exec_op,
	.supports_op = cadence_spi_mem_supports_op,
	};

	static const struct dm_spi_ops cadence_spi_ops = {
	.set_speed = cadence_spi_set_speed,
	.set_mode = cadence_spi_set_mode,
	.mem_ops = &cadence_spi_mem_ops,
	/*
	* cs_info is not needed, since we require all chip selects to be
	* in the device tree explicitly
	*/
	};

	static const struct udevice_id cadence_spi_ids[] = {
	{ .compatible = "cdns,qspi-nor" },
	{ .compatible = "ti,am654-ospi" },
	{ }
	};

	U_BOOT_DRIVER(cadence_spi) = {
	.name = "cadence_spi",
	.id = UCLASS_SPI,
	.of_match = cadence_spi_ids,
	.ops = &cadence_spi_ops,
	.of_to_plat = cadence_spi_of_to_plat,
	.plat_auto = sizeof(struct cadence_spi_plat),
	.priv_auto = sizeof(struct cadence_spi_priv),
	.probe = cadence_spi_probe,
	.remove = cadence_spi_remove,
	.flags = DM_FLAG_OS_PREPARE,
	};