drivers/mtd/spi/spi-nor-tiny.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Based on m25p80.c, by Mike Lavender (mike@steroidmicros.com), with
 * influence from lart.c (Abraham Van Der Merwe) and mtd_dataflash.c
 *
 * Copyright (C) 2005, Intec Automation Inc.
 * Copyright (C) 2014, Freescale Semiconductor, Inc.
 *
 * Synced from Linux v4.19
 */

#include <common.h>
#include <log.h>
#include <dm/device_compat.h>
#include <linux/err.h>
#include <linux/errno.h>
#include <linux/log2.h>
#include <linux/math64.h>
#include <linux/sizes.h>

#include <linux/mtd/mtd.h>
#include <linux/mtd/spi-nor.h>
#include <spi-mem.h>
#include <spi.h>

#include "sf_internal.h"

/* Define max times to check status register before we give up. */

/*
 * For everything but full-chip erase; probably could be much smaller, but kept
 * around for safety for now
 */

#define HZ					CONFIG_SYS_HZ

#define DEFAULT_READY_WAIT_JIFFIES		(40UL * HZ)

static int spi_nor_read_write_reg(struct spi_nor *nor, struct spi_mem_op
		*op, void *buf)
{
	if (op->data.dir == SPI_MEM_DATA_IN)
		op->data.buf.in = buf;
	else
		op->data.buf.out = buf;
	return spi_mem_exec_op(nor->spi, op);
}

static int spi_nor_read_reg(struct spi_nor *nor, u8 code, u8 *val, int len)
{
	struct spi_mem_op op = SPI_MEM_OP(SPI_MEM_OP_CMD(code, 1),
					  SPI_MEM_OP_NO_ADDR,
					  SPI_MEM_OP_NO_DUMMY,
					  SPI_MEM_OP_DATA_IN(len, NULL, 1));
	int ret;

	ret = spi_nor_read_write_reg(nor, &op, val);
	if (ret < 0) {
		/*
		 * spi_slave does not have a struct udevice member without DM,
		 * so use the bus and cs instead.
		 */
#if CONFIG_IS_ENABLED(DM_SPI)
		dev_dbg(nor->spi->dev, "error %d reading %x\n", ret,
			code);
#else
		log_debug("spi%u.%u: error %d reading %x\n",
			  nor->spi->bus, nor->spi->cs, ret, code);
#endif
	}

	return ret;
}

static int spi_nor_write_reg(struct spi_nor *nor, u8 opcode, u8 *buf, int len)
{
	struct spi_mem_op op = SPI_MEM_OP(SPI_MEM_OP_CMD(opcode, 1),
					  SPI_MEM_OP_NO_ADDR,
					  SPI_MEM_OP_NO_DUMMY,
					  SPI_MEM_OP_DATA_OUT(len, NULL, 1));

	return spi_nor_read_write_reg(nor, &op, buf);
}

static ssize_t spi_nor_read_data(struct spi_nor *nor, loff_t from, size_t len,
				 u_char *buf)
{
	struct spi_mem_op op =
			SPI_MEM_OP(SPI_MEM_OP_CMD(nor->read_opcode, 1),
				   SPI_MEM_OP_ADDR(nor->addr_width, from, 1),
				   SPI_MEM_OP_DUMMY(nor->read_dummy, 1),
				   SPI_MEM_OP_DATA_IN(len, buf, 1));
	size_t remaining = len;
	int ret;

	/* get transfer protocols. */
	op.cmd.buswidth = spi_nor_get_protocol_inst_nbits(nor->read_proto);
	op.addr.buswidth = spi_nor_get_protocol_addr_nbits(nor->read_proto);
	op.dummy.buswidth = op.addr.buswidth;
	op.data.buswidth = spi_nor_get_protocol_data_nbits(nor->read_proto);

	/* convert the dummy cycles to the number of bytes */
	op.dummy.nbytes = (nor->read_dummy * op.dummy.buswidth) / 8;

	while (remaining) {
		op.data.nbytes = remaining < UINT_MAX ? remaining : UINT_MAX;
		ret = spi_mem_adjust_op_size(nor->spi, &op);
		if (ret)
			return ret;

		ret = spi_mem_exec_op(nor->spi, &op);
		if (ret)
			return ret;

		op.addr.val += op.data.nbytes;
		remaining -= op.data.nbytes;
		op.data.buf.in += op.data.nbytes;
	}

	return len;
}

#if defined(CONFIG_SPI_FLASH_SPANSION) || defined(CONFIG_SPI_FLASH_WINBOND)
/*
 * Read configuration register, returning its value in the
 * location. Return the configuration register value.
 * Returns negative if error occurred.
 */
static int read_cr(struct spi_nor *nor)
{
	int ret;
	u8 val;

	ret = spi_nor_read_reg(nor, SPINOR_OP_RDCR, &val, 1);
	if (ret < 0) {
		dev_dbg(nor->dev, "error %d reading CR\n", ret);
		return ret;
	}

	return val;
}
#endif

/*
 * Write status register 1 byte
 * Returns negative if error occurred.
 */
static inline int write_sr(struct spi_nor *nor, u8 val)
{
	nor->cmd_buf[0] = val;
	return spi_nor_write_reg(nor, SPINOR_OP_WRSR, nor->cmd_buf, 1);
}

/*
 * Set write enable latch with Write Enable command.
 * Returns negative if error occurred.
 */
static inline int write_enable(struct spi_nor *nor)
{
	return spi_nor_write_reg(nor, SPINOR_OP_WREN, NULL, 0);
}

/*
 * Send write disable instruction to the chip.
 */
static inline int write_disable(struct spi_nor *nor)
{
	return spi_nor_write_reg(nor, SPINOR_OP_WRDI, NULL, 0);
}

static inline struct spi_nor *mtd_to_spi_nor(struct mtd_info *mtd)
{
	return mtd->priv;
}

static u8 spi_nor_convert_opcode(u8 opcode, const u8 table[][2], size_t size)
{
	size_t i;

	for (i = 0; i < size; i++)
		if (table[i][0] == opcode)
			return table[i][1];

	/* No conversion found, keep input op code. */
	return opcode;
}

static inline u8 spi_nor_convert_3to4_read(u8 opcode)
{
	static const u8 spi_nor_3to4_read[][2] = {
		{ SPINOR_OP_READ,	SPINOR_OP_READ_4B },
		{ SPINOR_OP_READ_FAST,	SPINOR_OP_READ_FAST_4B },
		{ SPINOR_OP_READ_1_1_2,	SPINOR_OP_READ_1_1_2_4B },
		{ SPINOR_OP_READ_1_2_2,	SPINOR_OP_READ_1_2_2_4B },
		{ SPINOR_OP_READ_1_1_4,	SPINOR_OP_READ_1_1_4_4B },
		{ SPINOR_OP_READ_1_4_4,	SPINOR_OP_READ_1_4_4_4B },
	};

	return spi_nor_convert_opcode(opcode, spi_nor_3to4_read,
				      ARRAY_SIZE(spi_nor_3to4_read));
}

static void spi_nor_set_4byte_opcodes(struct spi_nor *nor,
				      const struct flash_info *info)
{
	nor->read_opcode = spi_nor_convert_3to4_read(nor->read_opcode);
}

/* Enable/disable 4-byte addressing mode. */
static inline int set_4byte(struct spi_nor *nor, const struct flash_info *info,
			    int enable)
{
	int status;
	bool need_wren = false;
	u8 cmd;

	switch (JEDEC_MFR(info)) {
	case SNOR_MFR_ST:
	case SNOR_MFR_MICRON:
		/* Some Micron need WREN command; all will accept it */
		need_wren = true;
	case SNOR_MFR_MACRONIX:
	case SNOR_MFR_WINBOND:
		if (need_wren)
			write_enable(nor);

		cmd = enable ? SPINOR_OP_EN4B : SPINOR_OP_EX4B;
		status = spi_nor_write_reg(nor, cmd, NULL, 0);
		if (need_wren)
			write_disable(nor);

		if (!status && !enable &&
		    JEDEC_MFR(info) == SNOR_MFR_WINBOND) {
			/*
			 * On Winbond W25Q256FV, leaving 4byte mode causes
			 * the Extended Address Register to be set to 1, so all
			 * 3-byte-address reads come from the second 16M.
			 * We must clear the register to enable normal behavior.
			 */
			write_enable(nor);
			nor->cmd_buf[0] = 0;
			spi_nor_write_reg(nor, SPINOR_OP_WREAR,
					  nor->cmd_buf, 1);
			write_disable(nor);
		}

		return status;
	default:
		/* Spansion style */
		nor->cmd_buf[0] = enable << 7;
		return spi_nor_write_reg(nor, SPINOR_OP_BRWR, nor->cmd_buf, 1);
	}
}

#if defined(CONFIG_SPI_FLASH_SPANSION) ||	\
	defined(CONFIG_SPI_FLASH_WINBOND) ||	\
	defined(CONFIG_SPI_FLASH_MACRONIX)
/*
 * Read the status register, returning its value in the location
 * Return the status register value.
 * Returns negative if error occurred.
 */
static int read_sr(struct spi_nor *nor)
{
	int ret;
	u8 val;

	ret = spi_nor_read_reg(nor, SPINOR_OP_RDSR, &val, 1);
	if (ret < 0) {
		pr_debug("error %d reading SR\n", (int)ret);
		return ret;
	}

	return val;
}

/*
 * Read the flag status register, returning its value in the location
 * Return the status register value.
 * Returns negative if error occurred.
 */
static int read_fsr(struct spi_nor *nor)
{
	int ret;
	u8 val;

	ret = spi_nor_read_reg(nor, SPINOR_OP_RDFSR, &val, 1);
	if (ret < 0) {
		pr_debug("error %d reading FSR\n", ret);
		return ret;
	}

	return val;
}

static int spi_nor_sr_ready(struct spi_nor *nor)
{
	int sr = read_sr(nor);

	if (sr < 0)
		return sr;

	return !(sr & SR_WIP);
}

static int spi_nor_fsr_ready(struct spi_nor *nor)
{
	int fsr = read_fsr(nor);

	if (fsr < 0)
		return fsr;
	return fsr & FSR_READY;
}

static int spi_nor_ready(struct spi_nor *nor)
{
	int sr, fsr;

	sr = spi_nor_sr_ready(nor);
	if (sr < 0)
		return sr;
	fsr = nor->flags & SNOR_F_USE_FSR ? spi_nor_fsr_ready(nor) : 1;
	if (fsr < 0)
		return fsr;
	return sr && fsr;
}

/*
 * Service routine to read status register until ready, or timeout occurs.
 * Returns non-zero if error.
 */
static int spi_nor_wait_till_ready_with_timeout(struct spi_nor *nor,
						unsigned long timeout)
{
	unsigned long timebase;
	int ret;

	timebase = get_timer(0);

	while (get_timer(timebase) < timeout) {
		ret = spi_nor_ready(nor);
		if (ret < 0)
			return ret;
		if (ret)
			return 0;
	}

	dev_err(nor->dev, "flash operation timed out\n");

	return -ETIMEDOUT;
}

static int spi_nor_wait_till_ready(struct spi_nor *nor)
{
	return spi_nor_wait_till_ready_with_timeout(nor,
						    DEFAULT_READY_WAIT_JIFFIES);
}
#endif /* CONFIG_SPI_FLASH_SPANSION */

/*
 * Erase an address range on the nor chip.  The address range may extend
 * one or more erase sectors.  Return an error is there is a problem erasing.
 */
static int spi_nor_erase(struct mtd_info *mtd, struct erase_info *instr)
{
	return -ENOTSUPP;
}

static const struct flash_info *spi_nor_read_id(struct spi_nor *nor)
{
	int			tmp;
	u8			id[SPI_NOR_MAX_ID_LEN];
	const struct flash_info	*info;

	tmp = spi_nor_read_reg(nor, SPINOR_OP_RDID, id, SPI_NOR_MAX_ID_LEN);
	if (tmp < 0) {
		dev_dbg(nor->dev, "error %d reading JEDEC ID\n", tmp);
		return ERR_PTR(tmp);
	}

	info = spi_nor_ids;
	for (; info->sector_size != 0; info++) {
		if (info->id_len) {
			if (!memcmp(info->id, id, info->id_len))
				return info;
		}
	}
	dev_dbg(nor->dev, "unrecognized JEDEC id bytes: %02x, %02x, %02x\n",
		id[0], id[1], id[2]);
	return ERR_PTR(-EMEDIUMTYPE);
}

static int spi_nor_read(struct mtd_info *mtd, loff_t from, size_t len,
			size_t *retlen, u_char *buf)
{
	struct spi_nor *nor = mtd_to_spi_nor(mtd);
	int ret;

	dev_dbg(nor->dev, "from 0x%08x, len %zd\n", (u32)from, len);

	while (len) {
		loff_t addr = from;

		ret = spi_nor_read_data(nor, addr, len, buf);
		if (ret == 0) {
			/* We shouldn't see 0-length reads */
			ret = -EIO;
			goto read_err;
		}
		if (ret < 0)
			goto read_err;

		*retlen += ret;
		buf += ret;
		from += ret;
		len -= ret;
	}
	ret = 0;

read_err:
	return ret;
}

/*
 * Write an address range to the nor chip.  Data must be written in
 * FLASH_PAGESIZE chunks.  The address range may be any size provided
 * it is within the physical boundaries.
 */
static int spi_nor_write(struct mtd_info *mtd, loff_t to, size_t len,
			 size_t *retlen, const u_char *buf)
{
	return -ENOTSUPP;
}

#ifdef CONFIG_SPI_FLASH_MACRONIX
/**
 * macronix_quad_enable() - set QE bit in Status Register.
 * @nor:	pointer to a 'struct spi_nor'
 *
 * Set the Quad Enable (QE) bit in the Status Register.
 *
 * bit 6 of the Status Register is the QE bit for Macronix like QSPI memories.
 *
 * Return: 0 on success, -errno otherwise.
 */
static int macronix_quad_enable(struct spi_nor *nor)
{
	int ret, val;

	val = read_sr(nor);
	if (val < 0)
		return val;
	if (val & SR_QUAD_EN_MX)
		return 0;

	write_enable(nor);

	write_sr(nor, val | SR_QUAD_EN_MX);

	ret = spi_nor_wait_till_ready(nor);
	if (ret)
		return ret;

	ret = read_sr(nor);
	if (!(ret > 0 && (ret & SR_QUAD_EN_MX))) {
		dev_err(nor->dev, "Macronix Quad bit not set\n");
		return -EINVAL;
	}

	return 0;
}
#endif

#if defined(CONFIG_SPI_FLASH_SPANSION) || defined(CONFIG_SPI_FLASH_WINBOND)
/*
 * Write status Register and configuration register with 2 bytes
 * The first byte will be written to the status register, while the
 * second byte will be written to the configuration register.
 * Return negative if error occurred.
 */
static int write_sr_cr(struct spi_nor *nor, u8 *sr_cr)
{
	int ret;

	write_enable(nor);

	ret = spi_nor_write_reg(nor, SPINOR_OP_WRSR, sr_cr, 2);
	if (ret < 0) {
		dev_dbg(nor->dev,
			"error while writing configuration register\n");
		return -EINVAL;
	}

	ret = spi_nor_wait_till_ready(nor);
	if (ret) {
		dev_dbg(nor->dev,
			"timeout while writing configuration register\n");
		return ret;
	}

	return 0;
}

/**
 * spansion_read_cr_quad_enable() - set QE bit in Configuration Register.
 * @nor:	pointer to a 'struct spi_nor'
 *
 * Set the Quad Enable (QE) bit in the Configuration Register.
 * This function should be used with QSPI memories supporting the Read
 * Configuration Register (35h) instruction.
 *
 * bit 1 of the Configuration Register is the QE bit for Spansion like QSPI
 * memories.
 *
 * Return: 0 on success, -errno otherwise.
 */
static int spansion_read_cr_quad_enable(struct spi_nor *nor)
{
	u8 sr_cr[2];
	int ret;

	/* Check current Quad Enable bit value. */
	ret = read_cr(nor);
	if (ret < 0) {
		dev_dbg(nor->dev,
			"error while reading configuration register\n");
		return -EINVAL;
	}

	if (ret & CR_QUAD_EN_SPAN)
		return 0;

	sr_cr[1] = ret | CR_QUAD_EN_SPAN;

	/* Keep the current value of the Status Register. */
	ret = read_sr(nor);
	if (ret < 0) {
		dev_dbg(nor->dev, "error while reading status register\n");
		return -EINVAL;
	}
	sr_cr[0] = ret;

	ret = write_sr_cr(nor, sr_cr);
	if (ret)
		return ret;

	/* Read back and check it. */
	ret = read_cr(nor);
	if (!(ret > 0 && (ret & CR_QUAD_EN_SPAN))) {
		dev_dbg(nor->dev, "Spansion Quad bit not set\n");
		return -EINVAL;
	}

	return 0;
}
#endif /* CONFIG_SPI_FLASH_SPANSION */

struct spi_nor_read_command {
	u8			num_mode_clocks;
	u8			num_wait_states;
	u8			opcode;
	enum spi_nor_protocol	proto;
};

enum spi_nor_read_command_index {
	SNOR_CMD_READ,
	SNOR_CMD_READ_FAST,

	/* Quad SPI */
	SNOR_CMD_READ_1_1_4,

	SNOR_CMD_READ_MAX
};

struct spi_nor_flash_parameter {
	struct spi_nor_hwcaps		hwcaps;
	struct spi_nor_read_command	reads[SNOR_CMD_READ_MAX];
};

static void
spi_nor_set_read_settings(struct spi_nor_read_command *read,
			  u8 num_mode_clocks,
			  u8 num_wait_states,
			  u8 opcode,
			  enum spi_nor_protocol proto)
{
	read->num_mode_clocks = num_mode_clocks;
	read->num_wait_states = num_wait_states;
	read->opcode = opcode;
	read->proto = proto;
}

static int spi_nor_init_params(struct spi_nor *nor,
			       const struct flash_info *info,
			       struct spi_nor_flash_parameter *params)
{
	/* (Fast) Read settings. */
	params->hwcaps.mask = SNOR_HWCAPS_READ;
	spi_nor_set_read_settings(&params->reads[SNOR_CMD_READ],
				  0, 0, SPINOR_OP_READ,
				  SNOR_PROTO_1_1_1);

	if (!(info->flags & SPI_NOR_NO_FR)) {
		params->hwcaps.mask |= SNOR_HWCAPS_READ_FAST;
		spi_nor_set_read_settings(&params->reads[SNOR_CMD_READ_FAST],
					  0, 8, SPINOR_OP_READ_FAST,
					  SNOR_PROTO_1_1_1);
	}

	if (info->flags & SPI_NOR_QUAD_READ) {
		params->hwcaps.mask |= SNOR_HWCAPS_READ_1_1_4;
		spi_nor_set_read_settings(&params->reads[SNOR_CMD_READ_1_1_4],
					  0, 8, SPINOR_OP_READ_1_1_4,
					  SNOR_PROTO_1_1_4);
	}

	return 0;
}

static int spi_nor_select_read(struct spi_nor *nor,
			       const struct spi_nor_flash_parameter *params,
			       u32 shared_hwcaps)
{
	int best_match = shared_hwcaps & SNOR_HWCAPS_READ_MASK;
	int cmd;
	const struct spi_nor_read_command *read;

	if (best_match < 0)
		return -EINVAL;

	if (best_match & SNOR_HWCAPS_READ_1_1_4)
		cmd = SNOR_CMD_READ_1_1_4;
	else if (best_match & SNOR_HWCAPS_READ_FAST)
		cmd = SNOR_CMD_READ_FAST;
	else
		cmd = SNOR_CMD_READ;

	read = &params->reads[cmd];
	nor->read_opcode = read->opcode;
	nor->read_proto = read->proto;

	/*
	 * In the spi-nor framework, we don't need to make the difference
	 * between mode clock cycles and wait state clock cycles.
	 * Indeed, the value of the mode clock cycles is used by a QSPI
	 * flash memory to know whether it should enter or leave its 0-4-4
	 * (Continuous Read / XIP) mode.
	 * eXecution In Place is out of the scope of the mtd sub-system.
	 * Hence we choose to merge both mode and wait state clock cycles
	 * into the so called dummy clock cycles.
	 */
	nor->read_dummy = read->num_mode_clocks + read->num_wait_states;
	return 0;
}

static int spi_nor_setup(struct spi_nor *nor, const struct flash_info *info,
			 const struct spi_nor_flash_parameter *params,
			 const struct spi_nor_hwcaps *hwcaps)
{
	u32 shared_mask;
	int err;

	/*
	 * Keep only the hardware capabilities supported by both the SPI
	 * controller and the SPI flash memory.
	 */
	shared_mask = hwcaps->mask & params->hwcaps.mask;

	/* Select the (Fast) Read command. */
	err = spi_nor_select_read(nor, params, shared_mask);
	if (err) {
		dev_dbg(nor->dev,
			"can't select read settings supported by both the SPI controller and memory.\n");
		return err;
	}

	/* Enable Quad I/O if needed. */
	if (spi_nor_get_protocol_width(nor->read_proto) == 4) {
		switch (JEDEC_MFR(info)) {
#ifdef CONFIG_SPI_FLASH_MACRONIX
		case SNOR_MFR_MACRONIX:
			err = macronix_quad_enable(nor);
			break;
#endif
		case SNOR_MFR_ST:
		case SNOR_MFR_MICRON:
			break;

		default:
#if defined(CONFIG_SPI_FLASH_SPANSION) || defined(CONFIG_SPI_FLASH_WINBOND)
			/* Kept only for backward compatibility purpose. */
			err = spansion_read_cr_quad_enable(nor);
#endif
			break;
		}
	}
	if (err) {
		dev_dbg(nor->dev, "quad mode not supported\n");
		return err;
	}

	return 0;
}

static int spi_nor_init(struct spi_nor *nor)
{
	if (nor->addr_width == 4 &&
	    (JEDEC_MFR(nor->info) != SNOR_MFR_SPANSION) &&
	    !(nor->info->flags & SPI_NOR_4B_OPCODES)) {
		/*
		 * If the RESET# pin isn't hooked up properly, or the system
		 * otherwise doesn't perform a reset command in the boot
		 * sequence, it's impossible to 100% protect against unexpected
		 * reboots (e.g., crashes). Warn the user (or hopefully, system
		 * designer) that this is bad.
		 */
		if (nor->flags & SNOR_F_BROKEN_RESET)
			printf("enabling reset hack; may not recover from unexpected reboots\n");
		set_4byte(nor, nor->info, 1);
	}

	return 0;
}

int spi_nor_scan(struct spi_nor *nor)
{
	struct spi_nor_flash_parameter params;
	const struct flash_info *info = NULL;
	struct mtd_info *mtd = &nor->mtd;
	struct spi_nor_hwcaps hwcaps = {
		.mask = SNOR_HWCAPS_READ |
			SNOR_HWCAPS_READ_FAST
	};
	struct spi_slave *spi = nor->spi;
	int ret;

	/* Reset SPI protocol for all commands. */
	nor->reg_proto = SNOR_PROTO_1_1_1;
	nor->read_proto = SNOR_PROTO_1_1_1;
	nor->write_proto = SNOR_PROTO_1_1_1;

	if (spi->mode & SPI_RX_QUAD)
		hwcaps.mask |= SNOR_HWCAPS_READ_1_1_4;

	info = spi_nor_read_id(nor);
	if (IS_ERR_OR_NULL(info))
		return PTR_ERR(info);
	/* Parse the Serial Flash Discoverable Parameters table. */
	ret = spi_nor_init_params(nor, info, &params);
	if (ret)
		return ret;

	mtd->name = "spi-flash";
	mtd->dev = nor->dev;
	mtd->priv = nor;
	mtd->type = MTD_NORFLASH;
	mtd->writesize = 1;
	mtd->flags = MTD_CAP_NORFLASH;
	mtd->size = info->sector_size * info->n_sectors;
	mtd->_erase = spi_nor_erase;
	mtd->_read = spi_nor_read;
	mtd->_write = spi_nor_write;

	nor->size = mtd->size;

	if (info->flags & USE_FSR)
		nor->flags |= SNOR_F_USE_FSR;
	if (info->flags & USE_CLSR)
		nor->flags |= SNOR_F_USE_CLSR;

	if (info->flags & SPI_NOR_NO_FR)
		params.hwcaps.mask &= ~SNOR_HWCAPS_READ_FAST;

	/*
	 * Configure the SPI memory:
	 * - select op codes for (Fast) Read, Page Program and Sector Erase.
	 * - set the number of dummy cycles (mode cycles + wait states).
	 * - set the SPI protocols for register and memory accesses.
	 * - set the Quad Enable bit if needed (required by SPI x-y-4 protos).
	 */
	ret = spi_nor_setup(nor, info, &params, &hwcaps);
	if (ret)
		return ret;

	if (nor->addr_width) {
		/* already configured from SFDP */
	} else if (info->addr_width) {
		nor->addr_width = info->addr_width;
	} else if (mtd->size > 0x1000000) {
		/* enable 4-byte addressing if the device exceeds 16MiB */
		nor->addr_width = 4;
		if (JEDEC_MFR(info) == SNOR_MFR_SPANSION ||
		    info->flags & SPI_NOR_4B_OPCODES)
			spi_nor_set_4byte_opcodes(nor, info);
	} else {
		nor->addr_width = 3;
	}

	if (nor->addr_width > SPI_NOR_MAX_ADDR_WIDTH) {
		dev_dbg(nor->dev, "address width is too large: %u\n",
			nor->addr_width);
		return -EINVAL;
	}

	/* Send all the required SPI flash commands to initialize device */
	nor->info = info;
	ret = spi_nor_init(nor);
	if (ret)
		return ret;

	return 0;
}

/* U-Boot specific functions, need to extend MTD to support these */
int spi_flash_cmd_get_sw_write_prot(struct spi_nor *nor)
{
	return -ENOTSUPP;
}