drivers/spi/bcm63xx_spi.c - platform/external/u-boot - Gitiles

 // SPDX-License-Identifier: GPL-2.0+
 /*
  * Copyright (C) 2017 Álvaro Fernández Rojas <noltari@gmail.com>
  *
  * Derived from linux/drivers/spi/spi-bcm63xx.c:
  *	Copyright (C) 2009-2012 Florian Fainelli <florian@openwrt.org>
  *	Copyright (C) 2010 Tanguy Bouzeloc <tanguy.bouzeloc@efixo.com>
  */

 #include <common.h>
 #include <clk.h>
 #include <dm.h>
 #include <malloc.h>
 #include <spi.h>
 #include <reset.h>
 #include <wait_bit.h>
 #include <asm/io.h>

 /* BCM6348 SPI core */
 #define SPI_6348_CLK			0x06
 #define SPI_6348_CMD			0x00
 #define SPI_6348_CTL			0x40
 #define SPI_6348_CTL_SHIFT		6
 #define SPI_6348_FILL			0x07
 #define SPI_6348_IR_MASK		0x04
 #define SPI_6348_IR_STAT		0x02
 #define SPI_6348_RX			0x80
 #define SPI_6348_RX_SIZE		0x3f
 #define SPI_6348_TX			0x41
 #define SPI_6348_TX_SIZE		0x3f

 /* BCM6358 SPI core */
 #define SPI_6358_CLK			0x706
 #define SPI_6358_CMD			0x700
 #define SPI_6358_CTL			0x000
 #define SPI_6358_CTL_SHIFT		14
 #define SPI_6358_FILL			0x707
 #define SPI_6358_IR_MASK		0x702
 #define SPI_6358_IR_STAT		0x704
 #define SPI_6358_RX			0x400
 #define SPI_6358_RX_SIZE		0x220
 #define SPI_6358_TX			0x002
 #define SPI_6358_TX_SIZE		0x21e

 /* SPI Clock register */
 #define SPI_CLK_SHIFT		0
 #define SPI_CLK_20MHZ		(0 << SPI_CLK_SHIFT)
 #define SPI_CLK_0_391MHZ	(1 << SPI_CLK_SHIFT)
 #define SPI_CLK_0_781MHZ	(2 << SPI_CLK_SHIFT)
 #define SPI_CLK_1_563MHZ	(3 << SPI_CLK_SHIFT)
 #define SPI_CLK_3_125MHZ	(4 << SPI_CLK_SHIFT)
 #define SPI_CLK_6_250MHZ	(5 << SPI_CLK_SHIFT)
 #define SPI_CLK_12_50MHZ	(6 << SPI_CLK_SHIFT)
 #define SPI_CLK_25MHZ		(7 << SPI_CLK_SHIFT)
 #define SPI_CLK_MASK		(7 << SPI_CLK_SHIFT)
 #define SPI_CLK_SSOFF_SHIFT	3
 #define SPI_CLK_SSOFF_2		(2 << SPI_CLK_SSOFF_SHIFT)
 #define SPI_CLK_SSOFF_MASK	(7 << SPI_CLK_SSOFF_SHIFT)
 #define SPI_CLK_BSWAP_SHIFT	7
 #define SPI_CLK_BSWAP_MASK	(1 << SPI_CLK_BSWAP_SHIFT)

 /* SPI Command register */
 #define SPI_CMD_OP_SHIFT	0
 #define SPI_CMD_OP_START	(0x3 << SPI_CMD_OP_SHIFT)
 #define SPI_CMD_SLAVE_SHIFT	4
 #define SPI_CMD_SLAVE_MASK	(0xf << SPI_CMD_SLAVE_SHIFT)
 #define SPI_CMD_PREPEND_SHIFT	8
 #define SPI_CMD_PREPEND_BYTES	0xf
 #define SPI_CMD_3WIRE_SHIFT	12
 #define SPI_CMD_3WIRE_MASK	(1 << SPI_CMD_3WIRE_SHIFT)

 /* SPI Control register */
 #define SPI_CTL_TYPE_FD_RW	0
 #define SPI_CTL_TYPE_HD_W	1
 #define SPI_CTL_TYPE_HD_R	2

 /* SPI Interrupt registers */
 #define SPI_IR_DONE_SHIFT	0
 #define SPI_IR_DONE_MASK	(1 << SPI_IR_DONE_SHIFT)
 #define SPI_IR_RXOVER_SHIFT	1
 #define SPI_IR_RXOVER_MASK	(1 << SPI_IR_RXOVER_SHIFT)
 #define SPI_IR_TXUNDER_SHIFT	2
 #define SPI_IR_TXUNDER_MASK	(1 << SPI_IR_TXUNDER_SHIFT)
 #define SPI_IR_TXOVER_SHIFT	3
 #define SPI_IR_TXOVER_MASK	(1 << SPI_IR_TXOVER_SHIFT)
 #define SPI_IR_RXUNDER_SHIFT	4
 #define SPI_IR_RXUNDER_MASK	(1 << SPI_IR_RXUNDER_SHIFT)
 #define SPI_IR_CLEAR_MASK	(SPI_IR_DONE_MASK |\
 				 SPI_IR_RXOVER_MASK |\
 				 SPI_IR_TXUNDER_MASK |\
 				 SPI_IR_TXOVER_MASK |\
 				 SPI_IR_RXUNDER_MASK)

 enum bcm63xx_regs_spi {
 	SPI_CLK,
 	SPI_CMD,
 	SPI_CTL,
 	SPI_CTL_SHIFT,
 	SPI_FILL,
 	SPI_IR_MASK,
 	SPI_IR_STAT,
 	SPI_RX,
 	SPI_RX_SIZE,
 	SPI_TX,
 	SPI_TX_SIZE,
 };

 struct bcm63xx_spi_priv {
 	const unsigned long *regs;
 	void __iomem *base;
 	size_t tx_bytes;
 	uint8_t num_cs;
 };

 #define SPI_CLK_CNT		8
 static const unsigned bcm63xx_spi_freq_table[SPI_CLK_CNT][2] = {
 	{ 25000000, SPI_CLK_25MHZ },
 	{ 20000000, SPI_CLK_20MHZ },
 	{ 12500000, SPI_CLK_12_50MHZ },
 	{  6250000, SPI_CLK_6_250MHZ },
 	{  3125000, SPI_CLK_3_125MHZ },
 	{  1563000, SPI_CLK_1_563MHZ },
 	{   781000, SPI_CLK_0_781MHZ },
 	{   391000, SPI_CLK_0_391MHZ }
 };

 static int bcm63xx_spi_cs_info(struct udevice *bus, uint cs,
 			   struct spi_cs_info *info)
 {
 	struct bcm63xx_spi_priv *priv = dev_get_priv(bus);

 	if (cs >= priv->num_cs) {
 		printf("no cs %u\n", cs);
 		return -EINVAL;
 	}

 	return 0;
 }

 static int bcm63xx_spi_set_mode(struct udevice *bus, uint mode)
 {
 	struct bcm63xx_spi_priv *priv = dev_get_priv(bus);
 	const unsigned long *regs = priv->regs;

 	if (mode & SPI_LSB_FIRST)
 		setbits_8(priv->base + regs[SPI_CLK], SPI_CLK_BSWAP_MASK);
 	else
 		clrbits_8(priv->base + regs[SPI_CLK], SPI_CLK_BSWAP_MASK);

 	return 0;
 }

 static int bcm63xx_spi_set_speed(struct udevice *bus, uint speed)
 {
 	struct bcm63xx_spi_priv *priv = dev_get_priv(bus);
 	const unsigned long *regs = priv->regs;
 	uint8_t clk_cfg;
 	int i;

 	/* default to lowest clock configuration */
 	clk_cfg = SPI_CLK_0_391MHZ;

 	/* find the closest clock configuration */
 	for (i = 0; i < SPI_CLK_CNT; i++) {
 		if (speed >= bcm63xx_spi_freq_table[i][0]) {
 			clk_cfg = bcm63xx_spi_freq_table[i][1];
 			break;
 		}
 	}

 	/* write clock configuration */
 	clrsetbits_8(priv->base + regs[SPI_CLK],
 		     SPI_CLK_SSOFF_MASK | SPI_CLK_MASK,
 		     clk_cfg | SPI_CLK_SSOFF_2);

 	return 0;
 }

 /*
  * BCM63xx SPI driver doesn't allow keeping CS active between transfers since
  * they are HW controlled.
  * However, it provides a mechanism to prepend write transfers prior to read
  * transfers (with a maximum prepend of 15 bytes), which is usually enough for
  * SPI-connected flashes since reading requires prepending a write transfer of
  * 5 bytes.
  *
  * This implementation takes advantage of the prepend mechanism and combines
  * multiple transfers into a single one where possible (single/multiple write
  * transfer(s) followed by a final read/write transfer).
  * However, it's not possible to buffer reads, which means that read transfers
  * should always be done as the final ones.
  * On the other hand, take into account that combining write transfers into
  * a single one is just buffering and doesn't require prepend mechanism.
  */
 static int bcm63xx_spi_xfer(struct udevice *dev, unsigned int bitlen,
 		const void *dout, void *din, unsigned long flags)
 {
 	struct bcm63xx_spi_priv *priv = dev_get_priv(dev->parent);
 	const unsigned long *regs = priv->regs;
 	size_t data_bytes = bitlen / 8;

 	if (flags & SPI_XFER_BEGIN) {
 		/* clear prepends */
 		priv->tx_bytes = 0;

 		/* initialize hardware */
 		writeb_be(0, priv->base + regs[SPI_IR_MASK]);
 	}

 	if (din) {
 		/* buffering reads not possible since cs is hw controlled */
 		if (!(flags & SPI_XFER_END)) {
 			printf("unable to buffer reads\n");
 			return -EINVAL;
 		}

 		/* check rx size */
 		 if (data_bytes > regs[SPI_RX_SIZE]) {
 			printf("max rx bytes exceeded\n");
 			return -EMSGSIZE;
 		}
 	}

 	if (dout) {
 		/* check tx size */
 		if (priv->tx_bytes + data_bytes > regs[SPI_TX_SIZE]) {
 			printf("max tx bytes exceeded\n");
 			return -EMSGSIZE;
 		}

 		/* copy tx data */
 		memcpy_toio(priv->base + regs[SPI_TX] + priv->tx_bytes,
 			    dout, data_bytes);
 		priv->tx_bytes += data_bytes;
 	}

 	if (flags & SPI_XFER_END) {
 		struct dm_spi_slave_platdata *plat =
 			dev_get_parent_platdata(dev);
 		uint16_t val, cmd;
 		int ret;

 		/* determine control config */
 		if (dout && !din) {
 			/* buffered write transfers */
 			val = priv->tx_bytes;
 			val |= (SPI_CTL_TYPE_HD_W << regs[SPI_CTL_SHIFT]);
 			priv->tx_bytes = 0;
 		} else {
 			if (dout && din && (flags & SPI_XFER_ONCE)) {
 				/* full duplex read/write */
 				val = data_bytes;
 				val |= (SPI_CTL_TYPE_FD_RW <<
 					regs[SPI_CTL_SHIFT]);
 				priv->tx_bytes = 0;
 			} else {
 				/* prepended write transfer */
 				val = data_bytes;
 				val |= (SPI_CTL_TYPE_HD_R <<
 					regs[SPI_CTL_SHIFT]);
 				if (priv->tx_bytes > SPI_CMD_PREPEND_BYTES) {
 					printf("max prepend bytes exceeded\n");
 					return -EMSGSIZE;
 				}
 			}
 		}

 		if (regs[SPI_CTL_SHIFT] >= 8)
 			writew_be(val, priv->base + regs[SPI_CTL]);
 		else
 			writeb_be(val, priv->base + regs[SPI_CTL]);

 		/* clear interrupts */
 		writeb_be(SPI_IR_CLEAR_MASK, priv->base + regs[SPI_IR_STAT]);

 		/* issue the transfer */
 		cmd = SPI_CMD_OP_START;
 		cmd |= (plat->cs << SPI_CMD_SLAVE_SHIFT) & SPI_CMD_SLAVE_MASK;
 		cmd |= (priv->tx_bytes << SPI_CMD_PREPEND_SHIFT);
 		if (plat->mode & SPI_3WIRE)
 			cmd |= SPI_CMD_3WIRE_MASK;
 		writew_be(cmd, priv->base + regs[SPI_CMD]);

 		/* enable interrupts */
 		writeb_be(SPI_IR_DONE_MASK, priv->base + regs[SPI_IR_MASK]);

 		ret = wait_for_bit_8(priv->base + regs[SPI_IR_STAT],
 				     SPI_IR_DONE_MASK, true, 1000, false);
 		if (ret) {
 			printf("interrupt timeout\n");
 			return ret;
 		}

 		/* copy rx data */
 		if (din)
 			memcpy_fromio(din, priv->base + regs[SPI_RX],
 				      data_bytes);
 	}

 	return 0;
 }

 static const struct dm_spi_ops bcm63xx_spi_ops = {
 	.cs_info = bcm63xx_spi_cs_info,
 	.set_mode = bcm63xx_spi_set_mode,
 	.set_speed = bcm63xx_spi_set_speed,
 	.xfer = bcm63xx_spi_xfer,
 };

 static const unsigned long bcm6348_spi_regs[] = {
 	[SPI_CLK] = SPI_6348_CLK,
 	[SPI_CMD] = SPI_6348_CMD,
 	[SPI_CTL] = SPI_6348_CTL,
 	[SPI_CTL_SHIFT] = SPI_6348_CTL_SHIFT,
 	[SPI_FILL] = SPI_6348_FILL,
 	[SPI_IR_MASK] = SPI_6348_IR_MASK,
 	[SPI_IR_STAT] = SPI_6348_IR_STAT,
 	[SPI_RX] = SPI_6348_RX,
 	[SPI_RX_SIZE] = SPI_6348_RX_SIZE,
 	[SPI_TX] = SPI_6348_TX,
 	[SPI_TX_SIZE] = SPI_6348_TX_SIZE,
 };

 static const unsigned long bcm6358_spi_regs[] = {
 	[SPI_CLK] = SPI_6358_CLK,
 	[SPI_CMD] = SPI_6358_CMD,
 	[SPI_CTL] = SPI_6358_CTL,
 	[SPI_CTL_SHIFT] = SPI_6358_CTL_SHIFT,
 	[SPI_FILL] = SPI_6358_FILL,
 	[SPI_IR_MASK] = SPI_6358_IR_MASK,
 	[SPI_IR_STAT] = SPI_6358_IR_STAT,
 	[SPI_RX] = SPI_6358_RX,
 	[SPI_RX_SIZE] = SPI_6358_RX_SIZE,
 	[SPI_TX] = SPI_6358_TX,
 	[SPI_TX_SIZE] = SPI_6358_TX_SIZE,
 };

 static const struct udevice_id bcm63xx_spi_ids[] = {
 	{
 		.compatible = "brcm,bcm6348-spi",
 		.data = (ulong)&bcm6348_spi_regs,
 	}, {
 		.compatible = "brcm,bcm6358-spi",
 		.data = (ulong)&bcm6358_spi_regs,
 	}, { /* sentinel */ }
 };

 static int bcm63xx_spi_child_pre_probe(struct udevice *dev)
 {
 	struct bcm63xx_spi_priv *priv = dev_get_priv(dev->parent);
 	const unsigned long *regs = priv->regs;
 	struct spi_slave *slave = dev_get_parent_priv(dev);
 	struct dm_spi_slave_platdata *plat = dev_get_parent_platdata(dev);

 	/* check cs */
 	if (plat->cs >= priv->num_cs) {
 		printf("no cs %u\n", plat->cs);
 		return -ENODEV;
 	}

 	/* max read/write sizes */
 	slave->max_read_size = regs[SPI_RX_SIZE];
 	slave->max_write_size = regs[SPI_TX_SIZE];

 	return 0;
 }

 static int bcm63xx_spi_probe(struct udevice *dev)
 {
 	struct bcm63xx_spi_priv *priv = dev_get_priv(dev);
 	const unsigned long *regs =
 		(const unsigned long *)dev_get_driver_data(dev);
 	struct reset_ctl rst_ctl;
 	struct clk clk;
 	int ret;

 	priv->base = dev_remap_addr(dev);
 	if (!priv->base)
 		return -EINVAL;

 	priv->regs = regs;
 	priv->num_cs = dev_read_u32_default(dev, "num-cs", 8);

 	/* enable clock */
 	ret = clk_get_by_index(dev, 0, &clk);
 	if (ret < 0)
 		return ret;

 	ret = clk_enable(&clk);
 	if (ret < 0)
 		return ret;

 	ret = clk_free(&clk);
 	if (ret < 0)
 		return ret;

 	/* perform reset */
 	ret = reset_get_by_index(dev, 0, &rst_ctl);
 	if (ret < 0)
 		return ret;

 	ret = reset_deassert(&rst_ctl);
 	if (ret < 0)
 		return ret;

 	ret = reset_free(&rst_ctl);
 	if (ret < 0)
 		return ret;

 	/* initialize hardware */
 	writeb_be(0, priv->base + regs[SPI_IR_MASK]);

 	/* set fill register */
 	writeb_be(0xff, priv->base + regs[SPI_FILL]);

 	return 0;
 }

 U_BOOT_DRIVER(bcm63xx_spi) = {
 	.name = "bcm63xx_spi",
 	.id = UCLASS_SPI,
 	.of_match = bcm63xx_spi_ids,
 	.ops = &bcm63xx_spi_ops,
 	.priv_auto_alloc_size = sizeof(struct bcm63xx_spi_priv),
 	.child_pre_probe = bcm63xx_spi_child_pre_probe,
 	.probe = bcm63xx_spi_probe,
 };
	// SPDX-License-Identifier: GPL-2.0+
	/*
	* Copyright (C) 2017 Álvaro Fernández Rojas <noltari@gmail.com>
	*
	* Derived from linux/drivers/spi/spi-bcm63xx.c:
	* Copyright (C) 2009-2012 Florian Fainelli <florian@openwrt.org>
	* Copyright (C) 2010 Tanguy Bouzeloc <tanguy.bouzeloc@efixo.com>
	*/

	#include <common.h>
	#include <clk.h>
	#include <dm.h>
	#include <malloc.h>
	#include <spi.h>
	#include <reset.h>
	#include <wait_bit.h>
	#include <asm/io.h>

	/* BCM6348 SPI core */
	#define SPI_6348_CLK 0x06
	#define SPI_6348_CMD 0x00
	#define SPI_6348_CTL 0x40
	#define SPI_6348_CTL_SHIFT 6
	#define SPI_6348_FILL 0x07
	#define SPI_6348_IR_MASK 0x04
	#define SPI_6348_IR_STAT 0x02
	#define SPI_6348_RX 0x80
	#define SPI_6348_RX_SIZE 0x3f
	#define SPI_6348_TX 0x41
	#define SPI_6348_TX_SIZE 0x3f

	/* BCM6358 SPI core */
	#define SPI_6358_CLK 0x706
	#define SPI_6358_CMD 0x700
	#define SPI_6358_CTL 0x000
	#define SPI_6358_CTL_SHIFT 14
	#define SPI_6358_FILL 0x707
	#define SPI_6358_IR_MASK 0x702
	#define SPI_6358_IR_STAT 0x704
	#define SPI_6358_RX 0x400
	#define SPI_6358_RX_SIZE 0x220
	#define SPI_6358_TX 0x002
	#define SPI_6358_TX_SIZE 0x21e

	/* SPI Clock register */
	#define SPI_CLK_SHIFT 0
	#define SPI_CLK_20MHZ (0 << SPI_CLK_SHIFT)
	#define SPI_CLK_0_391MHZ (1 << SPI_CLK_SHIFT)
	#define SPI_CLK_0_781MHZ (2 << SPI_CLK_SHIFT)
	#define SPI_CLK_1_563MHZ (3 << SPI_CLK_SHIFT)
	#define SPI_CLK_3_125MHZ (4 << SPI_CLK_SHIFT)
	#define SPI_CLK_6_250MHZ (5 << SPI_CLK_SHIFT)
	#define SPI_CLK_12_50MHZ (6 << SPI_CLK_SHIFT)
	#define SPI_CLK_25MHZ (7 << SPI_CLK_SHIFT)
	#define SPI_CLK_MASK (7 << SPI_CLK_SHIFT)
	#define SPI_CLK_SSOFF_SHIFT 3
	#define SPI_CLK_SSOFF_2 (2 << SPI_CLK_SSOFF_SHIFT)
	#define SPI_CLK_SSOFF_MASK (7 << SPI_CLK_SSOFF_SHIFT)
	#define SPI_CLK_BSWAP_SHIFT 7
	#define SPI_CLK_BSWAP_MASK (1 << SPI_CLK_BSWAP_SHIFT)

	/* SPI Command register */
	#define SPI_CMD_OP_SHIFT 0
	#define SPI_CMD_OP_START (0x3 << SPI_CMD_OP_SHIFT)
	#define SPI_CMD_SLAVE_SHIFT 4
	#define SPI_CMD_SLAVE_MASK (0xf << SPI_CMD_SLAVE_SHIFT)
	#define SPI_CMD_PREPEND_SHIFT 8
	#define SPI_CMD_PREPEND_BYTES 0xf
	#define SPI_CMD_3WIRE_SHIFT 12
	#define SPI_CMD_3WIRE_MASK (1 << SPI_CMD_3WIRE_SHIFT)

	/* SPI Control register */
	#define SPI_CTL_TYPE_FD_RW 0
	#define SPI_CTL_TYPE_HD_W 1
	#define SPI_CTL_TYPE_HD_R 2

	/* SPI Interrupt registers */
	#define SPI_IR_DONE_SHIFT 0
	#define SPI_IR_DONE_MASK (1 << SPI_IR_DONE_SHIFT)
	#define SPI_IR_RXOVER_SHIFT 1
	#define SPI_IR_RXOVER_MASK (1 << SPI_IR_RXOVER_SHIFT)
	#define SPI_IR_TXUNDER_SHIFT 2
	#define SPI_IR_TXUNDER_MASK (1 << SPI_IR_TXUNDER_SHIFT)
	#define SPI_IR_TXOVER_SHIFT 3
	#define SPI_IR_TXOVER_MASK (1 << SPI_IR_TXOVER_SHIFT)
	#define SPI_IR_RXUNDER_SHIFT 4
	#define SPI_IR_RXUNDER_MASK (1 << SPI_IR_RXUNDER_SHIFT)
	#define SPI_IR_CLEAR_MASK (SPI_IR_DONE_MASK \|\
	SPI_IR_RXOVER_MASK \|\
	SPI_IR_TXUNDER_MASK \|\
	SPI_IR_TXOVER_MASK \|\
	SPI_IR_RXUNDER_MASK)

	enum bcm63xx_regs_spi {
	SPI_CLK,
	SPI_CMD,
	SPI_CTL,
	SPI_CTL_SHIFT,
	SPI_FILL,
	SPI_IR_MASK,
	SPI_IR_STAT,
	SPI_RX,
	SPI_RX_SIZE,
	SPI_TX,
	SPI_TX_SIZE,
	};

	struct bcm63xx_spi_priv {
	const unsigned long *regs;
	void __iomem *base;
	size_t tx_bytes;
	uint8_t num_cs;
	};

	#define SPI_CLK_CNT 8
	static const unsigned bcm63xx_spi_freq_table[SPI_CLK_CNT][2] = {
	{ 25000000, SPI_CLK_25MHZ },
	{ 20000000, SPI_CLK_20MHZ },
	{ 12500000, SPI_CLK_12_50MHZ },
	{ 6250000, SPI_CLK_6_250MHZ },
	{ 3125000, SPI_CLK_3_125MHZ },
	{ 1563000, SPI_CLK_1_563MHZ },
	{ 781000, SPI_CLK_0_781MHZ },
	{ 391000, SPI_CLK_0_391MHZ }
	};

	static int bcm63xx_spi_cs_info(struct udevice *bus, uint cs,
	struct spi_cs_info *info)
	{
	struct bcm63xx_spi_priv *priv = dev_get_priv(bus);

	if (cs >= priv->num_cs) {
	printf("no cs %u\n", cs);
	return -EINVAL;
	}

	return 0;
	}

	static int bcm63xx_spi_set_mode(struct udevice *bus, uint mode)
	{
	struct bcm63xx_spi_priv *priv = dev_get_priv(bus);
	const unsigned long *regs = priv->regs;

	if (mode & SPI_LSB_FIRST)
	setbits_8(priv->base + regs[SPI_CLK], SPI_CLK_BSWAP_MASK);
	else
	clrbits_8(priv->base + regs[SPI_CLK], SPI_CLK_BSWAP_MASK);

	return 0;
	}

	static int bcm63xx_spi_set_speed(struct udevice *bus, uint speed)
	{
	struct bcm63xx_spi_priv *priv = dev_get_priv(bus);
	const unsigned long *regs = priv->regs;
	uint8_t clk_cfg;
	int i;

	/* default to lowest clock configuration */
	clk_cfg = SPI_CLK_0_391MHZ;

	/* find the closest clock configuration */
	for (i = 0; i < SPI_CLK_CNT; i++) {
	if (speed >= bcm63xx_spi_freq_table[i][0]) {
	clk_cfg = bcm63xx_spi_freq_table[i][1];
	break;
	}
	}

	/* write clock configuration */
	clrsetbits_8(priv->base + regs[SPI_CLK],
	SPI_CLK_SSOFF_MASK \| SPI_CLK_MASK,
	clk_cfg \| SPI_CLK_SSOFF_2);

	return 0;
	}

	/*
	* BCM63xx SPI driver doesn't allow keeping CS active between transfers since
	* they are HW controlled.
	* However, it provides a mechanism to prepend write transfers prior to read
	* transfers (with a maximum prepend of 15 bytes), which is usually enough for
	* SPI-connected flashes since reading requires prepending a write transfer of
	* 5 bytes.
	*
	* This implementation takes advantage of the prepend mechanism and combines
	* multiple transfers into a single one where possible (single/multiple write
	* transfer(s) followed by a final read/write transfer).
	* However, it's not possible to buffer reads, which means that read transfers
	* should always be done as the final ones.
	* On the other hand, take into account that combining write transfers into
	* a single one is just buffering and doesn't require prepend mechanism.
	*/
	static int bcm63xx_spi_xfer(struct udevice *dev, unsigned int bitlen,
	const void dout, void din, unsigned long flags)
	{
	struct bcm63xx_spi_priv *priv = dev_get_priv(dev->parent);
	const unsigned long *regs = priv->regs;
	size_t data_bytes = bitlen / 8;

	if (flags & SPI_XFER_BEGIN) {
	/* clear prepends */
	priv->tx_bytes = 0;

	/* initialize hardware */
	writeb_be(0, priv->base + regs[SPI_IR_MASK]);
	}

	if (din) {
	/* buffering reads not possible since cs is hw controlled */
	if (!(flags & SPI_XFER_END)) {
	printf("unable to buffer reads\n");
	return -EINVAL;
	}

	/* check rx size */
	if (data_bytes > regs[SPI_RX_SIZE]) {
	printf("max rx bytes exceeded\n");
	return -EMSGSIZE;
	}
	}

	if (dout) {
	/* check tx size */
	if (priv->tx_bytes + data_bytes > regs[SPI_TX_SIZE]) {
	printf("max tx bytes exceeded\n");
	return -EMSGSIZE;
	}

	/* copy tx data */
	memcpy_toio(priv->base + regs[SPI_TX] + priv->tx_bytes,
	dout, data_bytes);
	priv->tx_bytes += data_bytes;
	}

	if (flags & SPI_XFER_END) {
	struct dm_spi_slave_platdata *plat =
	dev_get_parent_platdata(dev);
	uint16_t val, cmd;
	int ret;

	/* determine control config */
	if (dout && !din) {
	/* buffered write transfers */
	val = priv->tx_bytes;
	val \|= (SPI_CTL_TYPE_HD_W << regs[SPI_CTL_SHIFT]);
	priv->tx_bytes = 0;
	} else {
	if (dout && din && (flags & SPI_XFER_ONCE)) {
	/* full duplex read/write */
	val = data_bytes;
	val \|= (SPI_CTL_TYPE_FD_RW <<
	regs[SPI_CTL_SHIFT]);
	priv->tx_bytes = 0;
	} else {
	/* prepended write transfer */
	val = data_bytes;
	val \|= (SPI_CTL_TYPE_HD_R <<
	regs[SPI_CTL_SHIFT]);
	if (priv->tx_bytes > SPI_CMD_PREPEND_BYTES) {
	printf("max prepend bytes exceeded\n");
	return -EMSGSIZE;
	}
	}
	}

	if (regs[SPI_CTL_SHIFT] >= 8)
	writew_be(val, priv->base + regs[SPI_CTL]);
	else
	writeb_be(val, priv->base + regs[SPI_CTL]);

	/* clear interrupts */
	writeb_be(SPI_IR_CLEAR_MASK, priv->base + regs[SPI_IR_STAT]);

	/* issue the transfer */
	cmd = SPI_CMD_OP_START;
	cmd \|= (plat->cs << SPI_CMD_SLAVE_SHIFT) & SPI_CMD_SLAVE_MASK;
	cmd \|= (priv->tx_bytes << SPI_CMD_PREPEND_SHIFT);
	if (plat->mode & SPI_3WIRE)
	cmd \|= SPI_CMD_3WIRE_MASK;
	writew_be(cmd, priv->base + regs[SPI_CMD]);

	/* enable interrupts */
	writeb_be(SPI_IR_DONE_MASK, priv->base + regs[SPI_IR_MASK]);

	ret = wait_for_bit_8(priv->base + regs[SPI_IR_STAT],
	SPI_IR_DONE_MASK, true, 1000, false);
	if (ret) {
	printf("interrupt timeout\n");
	return ret;
	}

	/* copy rx data */
	if (din)
	memcpy_fromio(din, priv->base + regs[SPI_RX],
	data_bytes);
	}

	return 0;
	}

	static const struct dm_spi_ops bcm63xx_spi_ops = {
	.cs_info = bcm63xx_spi_cs_info,
	.set_mode = bcm63xx_spi_set_mode,
	.set_speed = bcm63xx_spi_set_speed,
	.xfer = bcm63xx_spi_xfer,
	};

	static const unsigned long bcm6348_spi_regs[] = {
	[SPI_CLK] = SPI_6348_CLK,
	[SPI_CMD] = SPI_6348_CMD,
	[SPI_CTL] = SPI_6348_CTL,
	[SPI_CTL_SHIFT] = SPI_6348_CTL_SHIFT,
	[SPI_FILL] = SPI_6348_FILL,
	[SPI_IR_MASK] = SPI_6348_IR_MASK,
	[SPI_IR_STAT] = SPI_6348_IR_STAT,
	[SPI_RX] = SPI_6348_RX,
	[SPI_RX_SIZE] = SPI_6348_RX_SIZE,
	[SPI_TX] = SPI_6348_TX,
	[SPI_TX_SIZE] = SPI_6348_TX_SIZE,
	};

	static const unsigned long bcm6358_spi_regs[] = {
	[SPI_CLK] = SPI_6358_CLK,
	[SPI_CMD] = SPI_6358_CMD,
	[SPI_CTL] = SPI_6358_CTL,
	[SPI_CTL_SHIFT] = SPI_6358_CTL_SHIFT,
	[SPI_FILL] = SPI_6358_FILL,
	[SPI_IR_MASK] = SPI_6358_IR_MASK,
	[SPI_IR_STAT] = SPI_6358_IR_STAT,
	[SPI_RX] = SPI_6358_RX,
	[SPI_RX_SIZE] = SPI_6358_RX_SIZE,
	[SPI_TX] = SPI_6358_TX,
	[SPI_TX_SIZE] = SPI_6358_TX_SIZE,
	};

	static const struct udevice_id bcm63xx_spi_ids[] = {
	{
	.compatible = "brcm,bcm6348-spi",
	.data = (ulong)&bcm6348_spi_regs,
	}, {
	.compatible = "brcm,bcm6358-spi",
	.data = (ulong)&bcm6358_spi_regs,
	}, { /* sentinel */ }
	};

	static int bcm63xx_spi_child_pre_probe(struct udevice *dev)
	{
	struct bcm63xx_spi_priv *priv = dev_get_priv(dev->parent);
	const unsigned long *regs = priv->regs;
	struct spi_slave *slave = dev_get_parent_priv(dev);
	struct dm_spi_slave_platdata *plat = dev_get_parent_platdata(dev);

	/* check cs */
	if (plat->cs >= priv->num_cs) {
	printf("no cs %u\n", plat->cs);
	return -ENODEV;
	}

	/* max read/write sizes */
	slave->max_read_size = regs[SPI_RX_SIZE];
	slave->max_write_size = regs[SPI_TX_SIZE];

	return 0;
	}

	static int bcm63xx_spi_probe(struct udevice *dev)
	{
	struct bcm63xx_spi_priv *priv = dev_get_priv(dev);
	const unsigned long *regs =
	(const unsigned long *)dev_get_driver_data(dev);
	struct reset_ctl rst_ctl;
	struct clk clk;
	int ret;

	priv->base = dev_remap_addr(dev);
	if (!priv->base)
	return -EINVAL;

	priv->regs = regs;
	priv->num_cs = dev_read_u32_default(dev, "num-cs", 8);

	/* enable clock */
	ret = clk_get_by_index(dev, 0, &clk);
	if (ret < 0)
	return ret;

	ret = clk_enable(&clk);
	if (ret < 0)
	return ret;

	ret = clk_free(&clk);
	if (ret < 0)
	return ret;

	/* perform reset */
	ret = reset_get_by_index(dev, 0, &rst_ctl);
	if (ret < 0)
	return ret;

	ret = reset_deassert(&rst_ctl);
	if (ret < 0)
	return ret;

	ret = reset_free(&rst_ctl);
	if (ret < 0)
	return ret;

	/* initialize hardware */
	writeb_be(0, priv->base + regs[SPI_IR_MASK]);

	/* set fill register */
	writeb_be(0xff, priv->base + regs[SPI_FILL]);

	return 0;
	}

	U_BOOT_DRIVER(bcm63xx_spi) = {
	.name = "bcm63xx_spi",
	.id = UCLASS_SPI,
	.of_match = bcm63xx_spi_ids,
	.ops = &bcm63xx_spi_ops,
	.priv_auto_alloc_size = sizeof(struct bcm63xx_spi_priv),
	.child_pre_probe = bcm63xx_spi_child_pre_probe,
	.probe = bcm63xx_spi_probe,
	};