spi-nor.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.
 */

#include <linux/err.h>
#include <linux/errno.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/mutex.h>
#include <linux/math64.h>
#include <linux/sizes.h>
#include <linux/slab.h>
#include <linux/sort.h>

#include <linux/mtd/mtd.h>
#include <linux/of_platform.h>
#include <linux/sched/task_stack.h>
#include <linux/spi/flash.h>
#include <linux/mtd/spi-nor.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 DEFAULT_READY_WAIT_JIFFIES		(40UL * HZ)

/*
 * For full-chip erase, calibrated to a 2MB flash (M25P16); should be scaled up
 * for larger flash
 */
#define CHIP_ERASE_2MB_READY_WAIT_JIFFIES	(40UL * HZ)

#define SPI_NOR_MAX_ID_LEN	6
#define SPI_NOR_MAX_ADDR_WIDTH	4

struct sfdp_parameter_header {
	u8		id_lsb;
	u8		minor;
	u8		major;
	u8		length; /* in double words */
	u8		parameter_table_pointer[3]; /* byte address */
	u8		id_msb;
};

#define SFDP_PARAM_HEADER_ID(p)	(((p)->id_msb << 8) | (p)->id_lsb)
#define SFDP_PARAM_HEADER_PTP(p) \
	(((p)->parameter_table_pointer[2] << 16) | \
	 ((p)->parameter_table_pointer[1] <<  8) | \
	 ((p)->parameter_table_pointer[0] <<  0))

#define SFDP_BFPT_ID		0xff00	/* Basic Flash Parameter Table */
#define SFDP_SECTOR_MAP_ID	0xff81	/* Sector Map Table */
#define SFDP_4BAIT_ID		0xff84  /* 4-byte Address Instruction Table */

#define SFDP_SIGNATURE		0x50444653U
#define SFDP_JESD216_MAJOR	1
#define SFDP_JESD216_MINOR	0
#define SFDP_JESD216A_MINOR	5
#define SFDP_JESD216B_MINOR	6

struct sfdp_header {
	u32		signature; /* Ox50444653U <=> "SFDP" */
	u8		minor;
	u8		major;
	u8		nph; /* 0-base number of parameter headers */
	u8		unused;

	/* Basic Flash Parameter Table. */
	struct sfdp_parameter_header	bfpt_header;
};

/* Basic Flash Parameter Table */

/*
 * JESD216 rev B defines a Basic Flash Parameter Table of 16 DWORDs.
 * They are indexed from 1 but C arrays are indexed from 0.
 */
#define BFPT_DWORD(i)		((i) - 1)
#define BFPT_DWORD_MAX		16

/* The first version of JESB216 defined only 9 DWORDs. */
#define BFPT_DWORD_MAX_JESD216			9

/* 1st DWORD. */
#define BFPT_DWORD1_FAST_READ_1_1_2		BIT(16)
#define BFPT_DWORD1_ADDRESS_BYTES_MASK		GENMASK(18, 17)
#define BFPT_DWORD1_ADDRESS_BYTES_3_ONLY	(0x0UL << 17)
#define BFPT_DWORD1_ADDRESS_BYTES_3_OR_4	(0x1UL << 17)
#define BFPT_DWORD1_ADDRESS_BYTES_4_ONLY	(0x2UL << 17)
#define BFPT_DWORD1_DTR				BIT(19)
#define BFPT_DWORD1_FAST_READ_1_2_2		BIT(20)
#define BFPT_DWORD1_FAST_READ_1_4_4		BIT(21)
#define BFPT_DWORD1_FAST_READ_1_1_4		BIT(22)

/* 5th DWORD. */
#define BFPT_DWORD5_FAST_READ_2_2_2		BIT(0)
#define BFPT_DWORD5_FAST_READ_4_4_4		BIT(4)

/* 11th DWORD. */
#define BFPT_DWORD11_PAGE_SIZE_SHIFT		4
#define BFPT_DWORD11_PAGE_SIZE_MASK		GENMASK(7, 4)

/* 15th DWORD. */

/*
 * (from JESD216 rev B)
 * Quad Enable Requirements (QER):
 * - 000b: Device does not have a QE bit. Device detects 1-1-4 and 1-4-4
 *         reads based on instruction. DQ3/HOLD# functions are hold during
 *         instruction phase.
 * - 001b: QE is bit 1 of status register 2. It is set via Write Status with
 *         two data bytes where bit 1 of the second byte is one.
 *         [...]
 *         Writing only one byte to the status register has the side-effect of
 *         clearing status register 2, including the QE bit. The 100b code is
 *         used if writing one byte to the status register does not modify
 *         status register 2.
 * - 010b: QE is bit 6 of status register 1. It is set via Write Status with
 *         one data byte where bit 6 is one.
 *         [...]
 * - 011b: QE is bit 7 of status register 2. It is set via Write status
 *         register 2 instruction 3Eh with one data byte where bit 7 is one.
 *         [...]
 *         The status register 2 is read using instruction 3Fh.
 * - 100b: QE is bit 1 of status register 2. It is set via Write Status with
 *         two data bytes where bit 1 of the second byte is one.
 *         [...]
 *         In contrast to the 001b code, writing one byte to the status
 *         register does not modify status register 2.
 * - 101b: QE is bit 1 of status register 2. Status register 1 is read using
 *         Read Status instruction 05h. Status register2 is read using
 *         instruction 35h. QE is set via Write Status instruction 01h with
 *         two data bytes where bit 1 of the second byte is one.
 *         [...]
 */
#define BFPT_DWORD15_QER_MASK			GENMASK(22, 20)
#define BFPT_DWORD15_QER_NONE			(0x0UL << 20) /* Micron */
#define BFPT_DWORD15_QER_SR2_BIT1_BUGGY		(0x1UL << 20)
#define BFPT_DWORD15_QER_SR1_BIT6		(0x2UL << 20) /* Macronix */
#define BFPT_DWORD15_QER_SR2_BIT7		(0x3UL << 20)
#define BFPT_DWORD15_QER_SR2_BIT1_NO_RD		(0x4UL << 20)
#define BFPT_DWORD15_QER_SR2_BIT1		(0x5UL << 20) /* Spansion */

struct sfdp_bfpt {
	u32	dwords[BFPT_DWORD_MAX];
};

/**
 * struct spi_nor_fixups - SPI NOR fixup hooks
 * @default_init: called after default flash parameters init. Used to tweak
 *                flash parameters when information provided by the flash_info
 *                table is incomplete or wrong.
 * @post_bfpt: called after the BFPT table has been parsed
 * @post_sfdp: called after SFDP has been parsed (is also called for SPI NORs
 *             that do not support RDSFDP). Typically used to tweak various
 *             parameters that could not be extracted by other means (i.e.
 *             when information provided by the SFDP/flash_info tables are
 *             incomplete or wrong).
 *
 * Those hooks can be used to tweak the SPI NOR configuration when the SFDP
 * table is broken or not available.
 */
struct spi_nor_fixups {
	void (*default_init)(struct spi_nor *nor);
	int (*post_bfpt)(struct spi_nor *nor,
			 const struct sfdp_parameter_header *bfpt_header,
			 const struct sfdp_bfpt *bfpt,
			 struct spi_nor_flash_parameter *params);
	void (*post_sfdp)(struct spi_nor *nor);
};

struct flash_info {
	char		*name;

	/*
	 * This array stores the ID bytes.
	 * The first three bytes are the JEDIC ID.
	 * JEDEC ID zero means "no ID" (mostly older chips).
	 */
	u8		id[SPI_NOR_MAX_ID_LEN];
	u8		id_len;

	/* The size listed here is what works with SPINOR_OP_SE, which isn't
	 * necessarily called a "sector" by the vendor.
	 */
	unsigned	sector_size;
	u16		n_sectors;

	u16		page_size;
	u16		addr_width;

	u16		flags;
#define SECT_4K			BIT(0)	/* SPINOR_OP_BE_4K works uniformly */
#define SPI_NOR_NO_ERASE	BIT(1)	/* No erase command needed */
#define SST_WRITE		BIT(2)	/* use SST byte programming */
#define SPI_NOR_NO_FR		BIT(3)	/* Can't do fastread */
#define SECT_4K_PMC		BIT(4)	/* SPINOR_OP_BE_4K_PMC works uniformly */
#define SPI_NOR_DUAL_READ	BIT(5)	/* Flash supports Dual Read */
#define SPI_NOR_QUAD_READ	BIT(6)	/* Flash supports Quad Read */
#define USE_FSR			BIT(7)	/* use flag status register */
#define SPI_NOR_HAS_LOCK	BIT(8)	/* Flash supports lock/unlock via SR */
#define SPI_NOR_HAS_TB		BIT(9)	/*
					 * Flash SR has Top/Bottom (TB) protect
					 * bit. Must be used with
					 * SPI_NOR_HAS_LOCK.
					 */
#define SPI_NOR_XSR_RDY		BIT(10)	/*
					 * S3AN flashes have specific opcode to
					 * read the status register.
					 * Flags SPI_NOR_XSR_RDY and SPI_S3AN
					 * use the same bit as one implies the
					 * other, but we will get rid of
					 * SPI_S3AN soon.
					 */
#define	SPI_S3AN		BIT(10)	/*
					 * Xilinx Spartan 3AN In-System Flash
					 * (MFR cannot be used for probing
					 * because it has the same value as
					 * ATMEL flashes)
					 */
#define SPI_NOR_4B_OPCODES	BIT(11)	/*
					 * Use dedicated 4byte address op codes
					 * to support memory size above 128Mib.
					 */
#define NO_CHIP_ERASE		BIT(12) /* Chip does not support chip erase */
#define SPI_NOR_SKIP_SFDP	BIT(13)	/* Skip parsing of SFDP tables */
#define USE_CLSR		BIT(14)	/* use CLSR command */
#define SPI_NOR_OCTAL_READ	BIT(15)	/* Flash supports Octal Read */

	/* Part specific fixup hooks. */
	const struct spi_nor_fixups *fixups;
};

#define JEDEC_MFR(info)	((info)->id[0])

/**
 * spi_nor_spimem_xfer_data() - helper function to read/write data to
 *                              flash's memory region
 * @nor:        pointer to 'struct spi_nor'
 * @op:         pointer to 'struct spi_mem_op' template for transfer
 *
 * Return: number of bytes transferred on success, -errno otherwise
 */
static ssize_t spi_nor_spimem_xfer_data(struct spi_nor *nor,
					struct spi_mem_op *op)
{
	bool usebouncebuf = false;
	void *rdbuf = NULL;
	const void *buf;
	int ret;

	if (op->data.dir == SPI_MEM_DATA_IN)
		buf = op->data.buf.in;
	else
		buf = op->data.buf.out;

	if (object_is_on_stack(buf) || !virt_addr_valid(buf))
		usebouncebuf = true;

	if (usebouncebuf) {
		if (op->data.nbytes > nor->bouncebuf_size)
			op->data.nbytes = nor->bouncebuf_size;

		if (op->data.dir == SPI_MEM_DATA_IN) {
			rdbuf = op->data.buf.in;
			op->data.buf.in = nor->bouncebuf;
		} else {
			op->data.buf.out = nor->bouncebuf;
			memcpy(nor->bouncebuf, buf,
			       op->data.nbytes);
		}
	}

	ret = spi_mem_adjust_op_size(nor->spimem, op);
	if (ret)
		return ret;

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

	if (usebouncebuf && op->data.dir == SPI_MEM_DATA_IN)
		memcpy(rdbuf, nor->bouncebuf, op->data.nbytes);

	return op->data.nbytes;
}

/**
 * spi_nor_spimem_read_data() - read data from flash's memory region via
 *                              spi-mem
 * @nor:        pointer to 'struct spi_nor'
 * @from:       offset to read from
 * @len:        number of bytes to read
 * @buf:        pointer to dst buffer
 *
 * Return: number of bytes read successfully, -errno otherwise
 */
static ssize_t spi_nor_spimem_read_data(struct spi_nor *nor, loff_t from,
					size_t len, u8 *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));

	/* 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;

	return spi_nor_spimem_xfer_data(nor, &op);
}

/**
 * spi_nor_read_data() - read data from flash memory
 * @nor:        pointer to 'struct spi_nor'
 * @from:       offset to read from
 * @len:        number of bytes to read
 * @buf:        pointer to dst buffer
 *
 * Return: number of bytes read successfully, -errno otherwise
 */
static ssize_t spi_nor_read_data(struct spi_nor *nor, loff_t from, size_t len,
				 u8 *buf)
{
	if (nor->spimem)
		return spi_nor_spimem_read_data(nor, from, len, buf);

	return nor->controller_ops->read(nor, from, len, buf);
}

/**
 * spi_nor_spimem_write_data() - write data to flash memory via
 *                               spi-mem
 * @nor:        pointer to 'struct spi_nor'
 * @to:         offset to write to
 * @len:        number of bytes to write
 * @buf:        pointer to src buffer
 *
 * Return: number of bytes written successfully, -errno otherwise
 */
static ssize_t spi_nor_spimem_write_data(struct spi_nor *nor, loff_t to,
					 size_t len, const u8 *buf)
{
	struct spi_mem_op op =
		SPI_MEM_OP(SPI_MEM_OP_CMD(nor->program_opcode, 1),
			   SPI_MEM_OP_ADDR(nor->addr_width, to, 1),
			   SPI_MEM_OP_NO_DUMMY,
			   SPI_MEM_OP_DATA_OUT(len, buf, 1));

	op.cmd.buswidth = spi_nor_get_protocol_inst_nbits(nor->write_proto);
	op.addr.buswidth = spi_nor_get_protocol_addr_nbits(nor->write_proto);
	op.data.buswidth = spi_nor_get_protocol_data_nbits(nor->write_proto);

	if (nor->program_opcode == SPINOR_OP_AAI_WP && nor->sst_write_second)
		op.addr.nbytes = 0;

	return spi_nor_spimem_xfer_data(nor, &op);
}

/**
 * spi_nor_write_data() - write data to flash memory
 * @nor:        pointer to 'struct spi_nor'
 * @to:         offset to write to
 * @len:        number of bytes to write
 * @buf:        pointer to src buffer
 *
 * Return: number of bytes written successfully, -errno otherwise
 */
static ssize_t spi_nor_write_data(struct spi_nor *nor, loff_t to, size_t len,
				  const u8 *buf)
{
	if (nor->spimem)
		return spi_nor_spimem_write_data(nor, to, len, buf);

	return nor->controller_ops->write(nor, to, len, buf);
}

/**
 * spi_nor_write_enable() - Set write enable latch with Write Enable command.
 * @nor:	pointer to 'struct spi_nor'.
 *
 * Return: 0 on success, -errno otherwise.
 */
static int spi_nor_write_enable(struct spi_nor *nor)
{
	int ret;

	if (nor->spimem) {
		struct spi_mem_op op =
			SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_WREN, 1),
				   SPI_MEM_OP_NO_ADDR,
				   SPI_MEM_OP_NO_DUMMY,
				   SPI_MEM_OP_NO_DATA);

		ret = spi_mem_exec_op(nor->spimem, &op);
	} else {
		ret = nor->controller_ops->write_reg(nor, SPINOR_OP_WREN,
						     NULL, 0);
	}

	if (ret)
		dev_dbg(nor->dev, "error %d on Write Enable\n", ret);

	return ret;
}

/**
 * spi_nor_write_disable() - Send Write Disable instruction to the chip.
 * @nor:	pointer to 'struct spi_nor'.
 *
 * Return: 0 on success, -errno otherwise.
 */
static int spi_nor_write_disable(struct spi_nor *nor)
{
	int ret;

	if (nor->spimem) {
		struct spi_mem_op op =
			SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_WRDI, 1),
				   SPI_MEM_OP_NO_ADDR,
				   SPI_MEM_OP_NO_DUMMY,
				   SPI_MEM_OP_NO_DATA);

		ret = spi_mem_exec_op(nor->spimem, &op);
	} else {
		ret = nor->controller_ops->write_reg(nor, SPINOR_OP_WRDI,
						     NULL, 0);
	}

	if (ret)
		dev_dbg(nor->dev, "error %d on Write Disable\n", ret);

	return ret;
}

/**
 * spi_nor_read_sr() - Read the Status Register.
 * @nor:	pointer to 'struct spi_nor'.
 * @sr:		pointer to a DMA-able buffer where the value of the
 *              Status Register will be written.
 *
 * Return: 0 on success, -errno otherwise.
 */
static int spi_nor_read_sr(struct spi_nor *nor, u8 *sr)
{
	int ret;

	if (nor->spimem) {
		struct spi_mem_op op =
			SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_RDSR, 1),
				   SPI_MEM_OP_NO_ADDR,
				   SPI_MEM_OP_NO_DUMMY,
				   SPI_MEM_OP_DATA_IN(1, sr, 1));

		ret = spi_mem_exec_op(nor->spimem, &op);
	} else {
		ret = nor->controller_ops->read_reg(nor, SPINOR_OP_RDSR,
						    sr, 1);
	}

	if (ret)
		dev_dbg(nor->dev, "error %d reading SR\n", ret);

	return ret;
}

/**
 * spi_nor_read_fsr() - Read the Flag Status Register.
 * @nor:	pointer to 'struct spi_nor'
 * @fsr:	pointer to a DMA-able buffer where the value of the
 *              Flag Status Register will be written.
 *
 * Return: 0 on success, -errno otherwise.
 */
static int spi_nor_read_fsr(struct spi_nor *nor, u8 *fsr)
{
	int ret;

	if (nor->spimem) {
		struct spi_mem_op op =
			SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_RDFSR, 1),
				   SPI_MEM_OP_NO_ADDR,
				   SPI_MEM_OP_NO_DUMMY,
				   SPI_MEM_OP_DATA_IN(1, fsr, 1));

		ret = spi_mem_exec_op(nor->spimem, &op);
	} else {
		ret = nor->controller_ops->read_reg(nor, SPINOR_OP_RDFSR,
						    fsr, 1);
	}

	if (ret)
		dev_dbg(nor->dev, "error %d reading FSR\n", ret);

	return ret;
}

/**
 * spi_nor_read_cr() - Read the Configuration Register using the
 * SPINOR_OP_RDCR (35h) command.
 * @nor:	pointer to 'struct spi_nor'
 * @cr:		pointer to a DMA-able buffer where the value of the
 *              Configuration Register will be written.
 *
 * Return: 0 on success, -errno otherwise.
 */
static int spi_nor_read_cr(struct spi_nor *nor, u8 *cr)
{
	int ret;

	if (nor->spimem) {
		struct spi_mem_op op =
			SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_RDCR, 1),
				   SPI_MEM_OP_NO_ADDR,
				   SPI_MEM_OP_NO_DUMMY,
				   SPI_MEM_OP_DATA_IN(1, cr, 1));

		ret = spi_mem_exec_op(nor->spimem, &op);
	} else {
		ret = nor->controller_ops->read_reg(nor, SPINOR_OP_RDCR, cr, 1);
	}

	if (ret)
		dev_dbg(nor->dev, "error %d reading CR\n", ret);

	return ret;
}

/**
 * macronix_set_4byte() - Set 4-byte address mode for Macronix flashes.
 * @nor:	pointer to 'struct spi_nor'.
 * @enable:	true to enter the 4-byte address mode, false to exit the 4-byte
 *		address mode.
 *
 * Return: 0 on success, -errno otherwise.
 */
static int macronix_set_4byte(struct spi_nor *nor, bool enable)
{
	int ret;

	if (nor->spimem) {
		struct spi_mem_op op =
			SPI_MEM_OP(SPI_MEM_OP_CMD(enable ?
						  SPINOR_OP_EN4B :
						  SPINOR_OP_EX4B,
						  1),
				  SPI_MEM_OP_NO_ADDR,
				  SPI_MEM_OP_NO_DUMMY,
				  SPI_MEM_OP_NO_DATA);

		ret = spi_mem_exec_op(nor->spimem, &op);
	} else {
		ret = nor->controller_ops->write_reg(nor,
						     enable ? SPINOR_OP_EN4B :
							      SPINOR_OP_EX4B,
						     NULL, 0);
	}

	if (ret)
		dev_dbg(nor->dev, "error %d setting 4-byte mode\n", ret);

	return ret;
}

/**
 * st_micron_set_4byte() - Set 4-byte address mode for ST and Micron flashes.
 * @nor:	pointer to 'struct spi_nor'.
 * @enable:	true to enter the 4-byte address mode, false to exit the 4-byte
 *		address mode.
 *
 * Return: 0 on success, -errno otherwise.
 */
static int st_micron_set_4byte(struct spi_nor *nor, bool enable)
{
	int ret;

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

	ret = macronix_set_4byte(nor, enable);
	if (ret)
		return ret;

	return spi_nor_write_disable(nor);
}

/**
 * spansion_set_4byte() - Set 4-byte address mode for Spansion flashes.
 * @nor:	pointer to 'struct spi_nor'.
 * @enable:	true to enter the 4-byte address mode, false to exit the 4-byte
 *		address mode.
 *
 * Return: 0 on success, -errno otherwise.
 */
static int spansion_set_4byte(struct spi_nor *nor, bool enable)
{
	int ret;

	nor->bouncebuf[0] = enable << 7;

	if (nor->spimem) {
		struct spi_mem_op op =
			SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_BRWR, 1),
				   SPI_MEM_OP_NO_ADDR,
				   SPI_MEM_OP_NO_DUMMY,
				   SPI_MEM_OP_DATA_OUT(1, nor->bouncebuf, 1));

		ret = spi_mem_exec_op(nor->spimem, &op);
	} else {
		ret = nor->controller_ops->write_reg(nor, SPINOR_OP_BRWR,
						     nor->bouncebuf, 1);
	}

	if (ret)
		dev_dbg(nor->dev, "error %d setting 4-byte mode\n", ret);

	return ret;
}

/**
 * spi_nor_write_ear() - Write Extended Address Register.
 * @nor:	pointer to 'struct spi_nor'.
 * @ear:	value to write to the Extended Address Register.
 *
 * Return: 0 on success, -errno otherwise.
 */
static int spi_nor_write_ear(struct spi_nor *nor, u8 ear)
{
	int ret;

	nor->bouncebuf[0] = ear;

	if (nor->spimem) {
		struct spi_mem_op op =
			SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_WREAR, 1),
				   SPI_MEM_OP_NO_ADDR,
				   SPI_MEM_OP_NO_DUMMY,
				   SPI_MEM_OP_DATA_OUT(1, nor->bouncebuf, 1));

		ret = spi_mem_exec_op(nor->spimem, &op);
	} else {
		ret = nor->controller_ops->write_reg(nor, SPINOR_OP_WREAR,
						     nor->bouncebuf, 1);
	}

	if (ret)
		dev_dbg(nor->dev, "error %d writing EAR\n", ret);

	return ret;
}

/**
 * winbond_set_4byte() - Set 4-byte address mode for Winbond flashes.
 * @nor:	pointer to 'struct spi_nor'.
 * @enable:	true to enter the 4-byte address mode, false to exit the 4-byte
 *		address mode.
 *
 * Return: 0 on success, -errno otherwise.
 */
static int winbond_set_4byte(struct spi_nor *nor, bool enable)
{
	int ret;

	ret = macronix_set_4byte(nor, enable);
	if (ret || enable)
		return ret;

	/*
	 * 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.
	 */
	ret = spi_nor_write_enable(nor);
	if (ret)
		return ret;

	ret = spi_nor_write_ear(nor, 0);
	if (ret)
		return ret;

	return spi_nor_write_disable(nor);
}

/**
 * spi_nor_xread_sr() - Read the Status Register on S3AN flashes.
 * @nor:	pointer to 'struct spi_nor'.
 * @sr:		pointer to a DMA-able buffer where the value of the
 *              Status Register will be written.
 *
 * Return: 0 on success, -errno otherwise.
 */
static int spi_nor_xread_sr(struct spi_nor *nor, u8 *sr)
{
	int ret;

	if (nor->spimem) {
		struct spi_mem_op op =
			SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_XRDSR, 1),
				   SPI_MEM_OP_NO_ADDR,
				   SPI_MEM_OP_NO_DUMMY,
				   SPI_MEM_OP_DATA_IN(1, sr, 1));

		ret = spi_mem_exec_op(nor->spimem, &op);
	} else {
		ret = nor->controller_ops->read_reg(nor, SPINOR_OP_XRDSR,
						    sr, 1);
	}

	if (ret)
		dev_dbg(nor->dev, "error %d reading XRDSR\n", ret);

	return ret;
}

/**
 * s3an_sr_ready() - Query the Status Register of the S3AN flash to see if the
 * flash is ready for new commands.
 * @nor:	pointer to 'struct spi_nor'.
 *
 * Return: 0 on success, -errno otherwise.
 */
static int s3an_sr_ready(struct spi_nor *nor)
{
	int ret;

	ret = spi_nor_xread_sr(nor, nor->bouncebuf);
	if (ret)
		return ret;

	return !!(nor->bouncebuf[0] & XSR_RDY);
}

/**
 * spi_nor_clear_sr() - Clear the Status Register.
 * @nor:	pointer to 'struct spi_nor'.
 */
static void spi_nor_clear_sr(struct spi_nor *nor)
{
	int ret;

	if (nor->spimem) {
		struct spi_mem_op op =
			SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_CLSR, 1),
				   SPI_MEM_OP_NO_ADDR,
				   SPI_MEM_OP_NO_DUMMY,
				   SPI_MEM_OP_NO_DATA);

		ret = spi_mem_exec_op(nor->spimem, &op);
	} else {
		ret = nor->controller_ops->write_reg(nor, SPINOR_OP_CLSR,
						     NULL, 0);
	}

	if (ret)
		dev_dbg(nor->dev, "error %d clearing SR\n", ret);
}

/**
 * spi_nor_sr_ready() - Query the Status Register to see if the flash is ready
 * for new commands.
 * @nor:	pointer to 'struct spi_nor'.
 *
 * Return: 0 on success, -errno otherwise.
 */
static int spi_nor_sr_ready(struct spi_nor *nor)
{
	int ret = spi_nor_read_sr(nor, nor->bouncebuf);

	if (ret)
		return ret;

	if (nor->flags & SNOR_F_USE_CLSR &&
	    nor->bouncebuf[0] & (SR_E_ERR | SR_P_ERR)) {
		if (nor->bouncebuf[0] & SR_E_ERR)
			dev_err(nor->dev, "Erase Error occurred\n");
		else
			dev_err(nor->dev, "Programming Error occurred\n");

		spi_nor_clear_sr(nor);
		return -EIO;
	}

	return !(nor->bouncebuf[0] & SR_WIP);
}

/**
 * spi_nor_clear_fsr() - Clear the Flag Status Register.
 * @nor:	pointer to 'struct spi_nor'.
 */
static void spi_nor_clear_fsr(struct spi_nor *nor)
{
	int ret;

	if (nor->spimem) {
		struct spi_mem_op op =
			SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_CLFSR, 1),
				   SPI_MEM_OP_NO_ADDR,
				   SPI_MEM_OP_NO_DUMMY,
				   SPI_MEM_OP_NO_DATA);

		ret = spi_mem_exec_op(nor->spimem, &op);
	} else {
		ret = nor->controller_ops->write_reg(nor, SPINOR_OP_CLFSR,
						     NULL, 0);
	}

	if (ret)
		dev_dbg(nor->dev, "error %d clearing FSR\n", ret);
}

/**
 * spi_nor_fsr_ready() - Query the Flag Status Register to see if the flash is
 * ready for new commands.
 * @nor:	pointer to 'struct spi_nor'.
 *
 * Return: 0 on success, -errno otherwise.
 */
static int spi_nor_fsr_ready(struct spi_nor *nor)
{
	int ret = spi_nor_read_fsr(nor, nor->bouncebuf);

	if (ret)
		return ret;

	if (nor->bouncebuf[0] & (FSR_E_ERR | FSR_P_ERR)) {
		if (nor->bouncebuf[0] & FSR_E_ERR)
			dev_err(nor->dev, "Erase operation failed.\n");
		else
			dev_err(nor->dev, "Program operation failed.\n");

		if (nor->bouncebuf[0] & FSR_PT_ERR)
			dev_err(nor->dev,
			"Attempted to modify a protected sector.\n");

		spi_nor_clear_fsr(nor);
		return -EIO;
	}

	return nor->bouncebuf[0] & FSR_READY;
}

/**
 * spi_nor_ready() - Query the flash to see if it is ready for new commands.
 * @nor:	pointer to 'struct spi_nor'.
 *
 * Return: 0 on success, -errno otherwise.
 */
static int spi_nor_ready(struct spi_nor *nor)
{
	int sr, fsr;

	if (nor->flags & SNOR_F_READY_XSR_RDY)
		sr = s3an_sr_ready(nor);
	else
		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;
}

/**
 * spi_nor_wait_till_ready_with_timeout() - Service routine to read the
 * Status Register until ready, or timeout occurs.
 * @nor:		pointer to "struct spi_nor".
 * @timeout_jiffies:	jiffies to wait until timeout.
 *
 * Return: 0 on success, -errno otherwise.
 */
static int spi_nor_wait_till_ready_with_timeout(struct spi_nor *nor,
						unsigned long timeout_jiffies)
{
	unsigned long deadline;
	int timeout = 0, ret;

	deadline = jiffies + timeout_jiffies;

	while (!timeout) {
		if (time_after_eq(jiffies, deadline))
			timeout = 1;

		ret = spi_nor_ready(nor);
		if (ret < 0)
			return ret;
		if (ret)
			return 0;

		cond_resched();
	}

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

	return -ETIMEDOUT;
}

/**
 * spi_nor_wait_till_ready() - Wait for a predefined amount of time for the
 * flash to be ready, or timeout occurs.
 * @nor:	pointer to "struct spi_nor".
 *
 * Return: 0 on success, -errno otherwise.
 */
static int spi_nor_wait_till_ready(struct spi_nor *nor)
{
	return spi_nor_wait_till_ready_with_timeout(nor,
						    DEFAULT_READY_WAIT_JIFFIES);
}

/**
 * spi_nor_write_sr() - Write the Status Register.
 * @nor:	pointer to 'struct spi_nor'.
 * @sr:		pointer to DMA-able buffer to write to the Status Register.
 * @len:	number of bytes to write to the Status Register.
 *
 * Return: 0 on success, -errno otherwise.
 */
static int spi_nor_write_sr(struct spi_nor *nor, const u8 *sr, size_t len)
{
	int ret;

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

	if (nor->spimem) {
		struct spi_mem_op op =
			SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_WRSR, 1),
				   SPI_MEM_OP_NO_ADDR,
				   SPI_MEM_OP_NO_DUMMY,
				   SPI_MEM_OP_DATA_OUT(len, sr, 1));

		ret = spi_mem_exec_op(nor->spimem, &op);
	} else {
		ret = nor->controller_ops->write_reg(nor, SPINOR_OP_WRSR,
						     sr, len);
	}

	if (ret) {
		dev_dbg(nor->dev, "error %d writing SR\n", ret);
		return ret;
	}

	return spi_nor_wait_till_ready(nor);
}

/**
 * spi_nor_write_sr1_and_check() - Write one byte to the Status Register 1 and
 * ensure that the byte written match the received value.
 * @nor:	pointer to a 'struct spi_nor'.
 * @sr1:	byte value to be written to the Status Register.
 *
 * Return: 0 on success, -errno otherwise.
 */
static int spi_nor_write_sr1_and_check(struct spi_nor *nor, u8 sr1)
{
	int ret;

	nor->bouncebuf[0] = sr1;

	ret = spi_nor_write_sr(nor, nor->bouncebuf, 1);
	if (ret)
		return ret;

	ret = spi_nor_read_sr(nor, nor->bouncebuf);
	if (ret)
		return ret;

	if (nor->bouncebuf[0] != sr1) {
		dev_dbg(nor->dev, "SR1: read back test failed\n");
		return -EIO;
	}

	return 0;
}

/**
 * spi_nor_write_16bit_sr_and_check() - Write the Status Register 1 and the
 * Status Register 2 in one shot. Ensure that the byte written in the Status
 * Register 1 match the received value, and that the 16-bit Write did not
 * affect what was already in the Status Register 2.
 * @nor:	pointer to a 'struct spi_nor'.
 * @sr1:	byte value to be written to the Status Register 1.
 *
 * Return: 0 on success, -errno otherwise.
 */
static int spi_nor_write_16bit_sr_and_check(struct spi_nor *nor, u8 sr1)
{
	int ret;
	u8 *sr_cr = nor->bouncebuf;
	u8 cr_written;

	/* Make sure we don't overwrite the contents of Status Register 2. */
	if (!(nor->flags & SNOR_F_NO_READ_CR)) {
		ret = spi_nor_read_cr(nor, &sr_cr[1]);
		if (ret)
			return ret;
	} else if (nor->params.quad_enable) {
		/*
		 * If the Status Register 2 Read command (35h) is not
		 * supported, we should at least be sure we don't
		 * change the value of the SR2 Quad Enable bit.
		 *
		 * We can safely assume that when the Quad Enable method is
		 * set, the value of the QE bit is one, as a consequence of the
		 * nor->params.quad_enable() call.
		 *
		 * We can safely assume that the Quad Enable bit is present in
		 * the Status Register 2 at BIT(1). According to the JESD216
		 * revB standard, BFPT DWORDS[15], bits 22:20, the 16-bit
		 * Write Status (01h) command is available just for the cases
		 * in which the QE bit is described in SR2 at BIT(1).
		 */
		sr_cr[1] = SR2_QUAD_EN_BIT1;
	} else {
		sr_cr[1] = 0;
	}

	sr_cr[0] = sr1;

	ret = spi_nor_write_sr(nor, sr_cr, 2);
	if (ret)
		return ret;

	if (nor->flags & SNOR_F_NO_READ_CR)
		return 0;

	cr_written = sr_cr[1];

	ret = spi_nor_read_cr(nor, &sr_cr[1]);
	if (ret)
		return ret;

	if (cr_written != sr_cr[1]) {
		dev_dbg(nor->dev, "CR: read back test failed\n");
		return -EIO;
	}

	return 0;
}

/**
 * spi_nor_write_sr_and_check() - Write the Status Register 1 and ensure that
 * the byte written match the received value without affecting other bits in the
 * Status Register 1 and 2.
 * @nor:	pointer to a 'struct spi_nor'.
 * @sr1:	byte value to be written to the Status Register.
 *
 * Return: 0 on success, -errno otherwise.
 */
static int spi_nor_write_sr_and_check(struct spi_nor *nor, u8 sr1)
{
	if (nor->flags & SNOR_F_HAS_16BIT_SR)
		return spi_nor_write_16bit_sr_and_check(nor, sr1);

	return spi_nor_write_sr1_and_check(nor, sr1);
}

/**
 * spi_nor_write_sr2() - Write the Status Register 2 using the
 * SPINOR_OP_WRSR2 (3eh) command.
 * @nor:	pointer to 'struct spi_nor'.
 * @sr2:	pointer to DMA-able buffer to write to the Status Register 2.
 *
 * Return: 0 on success, -errno otherwise.
 */
static int spi_nor_write_sr2(struct spi_nor *nor, const u8 *sr2)
{
	int ret;

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

	if (nor->spimem) {
		struct spi_mem_op op =
			SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_WRSR2, 1),
				   SPI_MEM_OP_NO_ADDR,
				   SPI_MEM_OP_NO_DUMMY,
				   SPI_MEM_OP_DATA_OUT(1, sr2, 1));

		ret = spi_mem_exec_op(nor->spimem, &op);
	} else {
		ret = nor->controller_ops->write_reg(nor, SPINOR_OP_WRSR2,
						     sr2, 1);
	}

	if (ret) {
		dev_dbg(nor->dev, "error %d writing SR2\n", ret);
		return ret;
	}

	return spi_nor_wait_till_ready(nor);
}

/**
 * spi_nor_read_sr2() - Read the Status Register 2 using the
 * SPINOR_OP_RDSR2 (3fh) command.
 * @nor:	pointer to 'struct spi_nor'.
 * @sr2:	pointer to DMA-able buffer where the value of the
 *		Status Register 2 will be written.
 *
 * Return: 0 on success, -errno otherwise.
 */
static int spi_nor_read_sr2(struct spi_nor *nor, u8 *sr2)
{
	int ret;

	if (nor->spimem) {
		struct spi_mem_op op =
			SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_RDSR2, 1),
				   SPI_MEM_OP_NO_ADDR,
				   SPI_MEM_OP_NO_DUMMY,
				   SPI_MEM_OP_DATA_IN(1, sr2, 1));

		ret = spi_mem_exec_op(nor->spimem, &op);
	} else {
		ret = nor->controller_ops->read_reg(nor, SPINOR_OP_RDSR2,
						    sr2, 1);
	}

	if (ret)
		dev_dbg(nor->dev, "error %d reading SR2\n", ret);

	return ret;
}

/**
 * spi_nor_erase_chip() - Erase the entire flash memory.
 * @nor:	pointer to 'struct spi_nor'.
 *
 * Return: 0 on success, -errno otherwise.
 */
static int spi_nor_erase_chip(struct spi_nor *nor)
{
	int ret;

	dev_dbg(nor->dev, " %lldKiB\n", (long long)(nor->mtd.size >> 10));

	if (nor->spimem) {
		struct spi_mem_op op =
			SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_CHIP_ERASE, 1),
				   SPI_MEM_OP_NO_ADDR,
				   SPI_MEM_OP_NO_DUMMY,
				   SPI_MEM_OP_NO_DATA);

		ret = spi_mem_exec_op(nor->spimem, &op);
	} else {
		ret = nor->controller_ops->write_reg(nor, SPINOR_OP_CHIP_ERASE,
						     NULL, 0);
	}

	if (ret)
		dev_dbg(nor->dev, "error %d erasing chip\n", ret);

	return ret;
}

static 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 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 },
		{ SPINOR_OP_READ_1_1_8,	SPINOR_OP_READ_1_1_8_4B },
		{ SPINOR_OP_READ_1_8_8,	SPINOR_OP_READ_1_8_8_4B },

		{ SPINOR_OP_READ_1_1_1_DTR,	SPINOR_OP_READ_1_1_1_DTR_4B },
		{ SPINOR_OP_READ_1_2_2_DTR,	SPINOR_OP_READ_1_2_2_DTR_4B },
		{ SPINOR_OP_READ_1_4_4_DTR,	SPINOR_OP_READ_1_4_4_DTR_4B },
	};

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

static u8 spi_nor_convert_3to4_program(u8 opcode)
{
	static const u8 spi_nor_3to4_program[][2] = {
		{ SPINOR_OP_PP,		SPINOR_OP_PP_4B },
		{ SPINOR_OP_PP_1_1_4,	SPINOR_OP_PP_1_1_4_4B },
		{ SPINOR_OP_PP_1_4_4,	SPINOR_OP_PP_1_4_4_4B },
		{ SPINOR_OP_PP_1_1_8,	SPINOR_OP_PP_1_1_8_4B },
		{ SPINOR_OP_PP_1_8_8,	SPINOR_OP_PP_1_8_8_4B },
	};

	return spi_nor_convert_opcode(opcode, spi_nor_3to4_program,
				      ARRAY_SIZE(spi_nor_3to4_program));
}

static u8 spi_nor_convert_3to4_erase(u8 opcode)
{
	static const u8 spi_nor_3to4_erase[][2] = {
		{ SPINOR_OP_BE_4K,	SPINOR_OP_BE_4K_4B },
		{ SPINOR_OP_BE_32K,	SPINOR_OP_BE_32K_4B },
		{ SPINOR_OP_SE,		SPINOR_OP_SE_4B },
	};

	return spi_nor_convert_opcode(opcode, spi_nor_3to4_erase,
				      ARRAY_SIZE(spi_nor_3to4_erase));
}

static void spi_nor_set_4byte_opcodes(struct spi_nor *nor)
{
	nor->read_opcode = spi_nor_convert_3to4_read(nor->read_opcode);
	nor->program_opcode = spi_nor_convert_3to4_program(nor->program_opcode);
	nor->erase_opcode = spi_nor_convert_3to4_erase(nor->erase_opcode);

	if (!spi_nor_has_uniform_erase(nor)) {
		struct spi_nor_erase_map *map = &nor->params.erase_map;
		struct spi_nor_erase_type *erase;
		int i;

		for (i = 0; i < SNOR_ERASE_TYPE_MAX; i++) {
			erase = &map->erase_type[i];
			erase->opcode =
				spi_nor_convert_3to4_erase(erase->opcode);
		}
	}
}

static int spi_nor_lock_and_prep(struct spi_nor *nor, enum spi_nor_ops ops)
{
	int ret = 0;

	mutex_lock(&nor->lock);

	if (nor->controller_ops &&  nor->controller_ops->prepare) {
		ret = nor->controller_ops->prepare(nor, ops);
		if (ret) {
			mutex_unlock(&nor->lock);
			return ret;
		}
	}
	return ret;
}

static void spi_nor_unlock_and_unprep(struct spi_nor *nor, enum spi_nor_ops ops)
{
	if (nor->controller_ops && nor->controller_ops->unprepare)
		nor->controller_ops->unprepare(nor, ops);
	mutex_unlock(&nor->lock);
}

/*
 * This code converts an address to the Default Address Mode, that has non
 * power of two page sizes. We must support this mode because it is the default
 * mode supported by Xilinx tools, it can access the whole flash area and
 * changing over to the Power-of-two mode is irreversible and corrupts the
 * original data.
 * Addr can safely be unsigned int, the biggest S3AN device is smaller than
 * 4 MiB.
 */
static u32 s3an_convert_addr(struct spi_nor *nor, u32 addr)
{
	u32 offset, page;

	offset = addr % nor->page_size;
	page = addr / nor->page_size;
	page <<= (nor->page_size > 512) ? 10 : 9;

	return page | offset;
}

static u32 spi_nor_convert_addr(struct spi_nor *nor, loff_t addr)
{
	if (!nor->params.convert_addr)
		return addr;

	return nor->params.convert_addr(nor, addr);
}

/*
 * Initiate the erasure of a single sector
 */
static int spi_nor_erase_sector(struct spi_nor *nor, u32 addr)
{
	int i;

	addr = spi_nor_convert_addr(nor, addr);

	if (nor->controller_ops && nor->controller_ops->erase)
		return nor->controller_ops->erase(nor, addr);

	if (nor->spimem) {
		struct spi_mem_op op =
			SPI_MEM_OP(SPI_MEM_OP_CMD(nor->erase_opcode, 1),
				   SPI_MEM_OP_ADDR(nor->addr_width, addr, 1),
				   SPI_MEM_OP_NO_DUMMY,
				   SPI_MEM_OP_NO_DATA);

		return spi_mem_exec_op(nor->spimem, &op);
	}

	/*
	 * Default implementation, if driver doesn't have a specialized HW
	 * control
	 */
	for (i = nor->addr_width - 1; i >= 0; i--) {
		nor->bouncebuf[i] = addr & 0xff;
		addr >>= 8;
	}

	return nor->controller_ops->write_reg(nor, nor->erase_opcode,
					      nor->bouncebuf, nor->addr_width);
}

/**
 * spi_nor_div_by_erase_size() - calculate remainder and update new dividend
 * @erase:	pointer to a structure that describes a SPI NOR erase type
 * @dividend:	dividend value
 * @remainder:	pointer to u32 remainder (will be updated)
 *
 * Return: the result of the division
 */
static u64 spi_nor_div_by_erase_size(const struct spi_nor_erase_type *erase,
				     u64 dividend, u32 *remainder)
{
	/* JEDEC JESD216B Standard imposes erase sizes to be power of 2. */
	*remainder = (u32)dividend & erase->size_mask;
	return dividend >> erase->size_shift;
}

/**
 * spi_nor_find_best_erase_type() - find the best erase type for the given
 *				    offset in the serial flash memory and the
 *				    number of bytes to erase. The region in
 *				    which the address fits is expected to be
 *				    provided.
 * @map:	the erase map of the SPI NOR
 * @region:	pointer to a structure that describes a SPI NOR erase region
 * @addr:	offset in the serial flash memory
 * @len:	number of bytes to erase
 *
 * Return: a pointer to the best fitted erase type, NULL otherwise.
 */
static const struct spi_nor_erase_type *
spi_nor_find_best_erase_type(const struct spi_nor_erase_map *map,
			     const struct spi_nor_erase_region *region,
			     u64 addr, u32 len)
{
	const struct spi_nor_erase_type *erase;
	u32 rem;
	int i;
	u8 erase_mask = region->offset & SNOR_ERASE_TYPE_MASK;

	/*
	 * Erase types are ordered by size, with the smallest erase type at
	 * index 0.
	 */
	for (i = SNOR_ERASE_TYPE_MAX - 1; i >= 0; i--) {
		/* Does the erase region support the tested erase type? */
		if (!(erase_mask & BIT(i)))
			continue;

		erase = &map->erase_type[i];

		/* Don't erase more than what the user has asked for. */
		if (erase->size > len)
			continue;

		/* Alignment is not mandatory for overlaid regions */
		if (region->offset & SNOR_OVERLAID_REGION)
			return erase;

		spi_nor_div_by_erase_size(erase, addr, &rem);
		if (rem)
			continue;
		else
			return erase;
	}

	return NULL;
}

/**
 * spi_nor_region_next() - get the next spi nor region
 * @region:	pointer to a structure that describes a SPI NOR erase region
 *
 * Return: the next spi nor region or NULL if last region.
 */
static struct spi_nor_erase_region *
spi_nor_region_next(struct spi_nor_erase_region *region)
{
	if (spi_nor_region_is_last(region))
		return NULL;
	region++;
	return region;
}

/**
 * spi_nor_find_erase_region() - find the region of the serial flash memory in
 *				 which the offset fits
 * @map:	the erase map of the SPI NOR
 * @addr:	offset in the serial flash memory
 *
 * Return: a pointer to the spi_nor_erase_region struct, ERR_PTR(-errno)
 *	   otherwise.
 */
static struct spi_nor_erase_region *
spi_nor_find_erase_region(const struct spi_nor_erase_map *map, u64 addr)
{
	struct spi_nor_erase_region *region = map->regions;
	u64 region_start = region->offset & ~SNOR_ERASE_FLAGS_MASK;
	u64 region_end = region_start + region->size;

	while (addr < region_start || addr >= region_end) {
		region = spi_nor_region_next(region);
		if (!region)
			return ERR_PTR(-EINVAL);

		region_start = region->offset & ~SNOR_ERASE_FLAGS_MASK;
		region_end = region_start + region->size;
	}

	return region;
}

/**
 * spi_nor_init_erase_cmd() - initialize an erase command
 * @region:	pointer to a structure that describes a SPI NOR erase region
 * @erase:	pointer to a structure that describes a SPI NOR erase type
 *
 * Return: the pointer to the allocated erase command, ERR_PTR(-errno)
 *	   otherwise.
 */
static struct spi_nor_erase_command *
spi_nor_init_erase_cmd(const struct spi_nor_erase_region *region,
		       const struct spi_nor_erase_type *erase)
{
	struct spi_nor_erase_command *cmd;

	cmd = kmalloc(sizeof(*cmd), GFP_KERNEL);
	if (!cmd)
		return ERR_PTR(-ENOMEM);

	INIT_LIST_HEAD(&cmd->list);
	cmd->opcode = erase->opcode;
	cmd->count = 1;

	if (region->offset & SNOR_OVERLAID_REGION)
		cmd->size = region->size;
	else
		cmd->size = erase->size;

	return cmd;
}

/**
 * spi_nor_destroy_erase_cmd_list() - destroy erase command list
 * @erase_list:	list of erase commands
 */
static void spi_nor_destroy_erase_cmd_list(struct list_head *erase_list)
{
	struct spi_nor_erase_command *cmd, *next;

	list_for_each_entry_safe(cmd, next, erase_list, list) {
		list_del(&cmd->list);
		kfree(cmd);
	}
}

/**
 * spi_nor_init_erase_cmd_list() - initialize erase command list
 * @nor:	pointer to a 'struct spi_nor'
 * @erase_list:	list of erase commands to be executed once we validate that the
 *		erase can be performed
 * @addr:	offset in the serial flash memory
 * @len:	number of bytes to erase
 *
 * Builds the list of best fitted erase commands and verifies if the erase can
 * be performed.
 *
 * Return: 0 on success, -errno otherwise.
 */
static int spi_nor_init_erase_cmd_list(struct spi_nor *nor,
				       struct list_head *erase_list,
				       u64 addr, u32 len)
{
	const struct spi_nor_erase_map *map = &nor->params.erase_map;
	const struct spi_nor_erase_type *erase, *prev_erase = NULL;
	struct spi_nor_erase_region *region;
	struct spi_nor_erase_command *cmd = NULL;
	u64 region_end;
	int ret = -EINVAL;

	region = spi_nor_find_erase_region(map, addr);
	if (IS_ERR(region))
		return PTR_ERR(region);

	region_end = spi_nor_region_end(region);

	while (len) {
		erase = spi_nor_find_best_erase_type(map, region, addr, len);
		if (!erase)
			goto destroy_erase_cmd_list;

		if (prev_erase != erase ||
		    region->offset & SNOR_OVERLAID_REGION) {
			cmd = spi_nor_init_erase_cmd(region, erase);
			if (IS_ERR(cmd)) {
				ret = PTR_ERR(cmd);
				goto destroy_erase_cmd_list;
			}

			list_add_tail(&cmd->list, erase_list);
		} else {
			cmd->count++;
		}

		addr += cmd->size;
		len -= cmd->size;

		if (len && addr >= region_end) {
			region = spi_nor_region_next(region);
			if (!region)
				goto destroy_erase_cmd_list;
			region_end = spi_nor_region_end(region);
		}

		prev_erase = erase;
	}

	return 0;

destroy_erase_cmd_list:
	spi_nor_destroy_erase_cmd_list(erase_list);
	return ret;
}

/**
 * spi_nor_erase_multi_sectors() - perform a non-uniform erase
 * @nor:	pointer to a 'struct spi_nor'
 * @addr:	offset in the serial flash memory
 * @len:	number of bytes to erase
 *
 * Build a list of best fitted erase commands and execute it once we validate
 * that the erase can be performed.
 *
 * Return: 0 on success, -errno otherwise.
 */
static int spi_nor_erase_multi_sectors(struct spi_nor *nor, u64 addr, u32 len)
{
	LIST_HEAD(erase_list);
	struct spi_nor_erase_command *cmd, *next;
	int ret;

	ret = spi_nor_init_erase_cmd_list(nor, &erase_list, addr, len);
	if (ret)
		return ret;

	list_for_each_entry_safe(cmd, next, &erase_list, list) {
		nor->erase_opcode = cmd->opcode;
		while (cmd->count) {
			ret = spi_nor_write_enable(nor);
			if (ret)
				goto destroy_erase_cmd_list;

			ret = spi_nor_erase_sector(nor, addr);
			if (ret)
				goto destroy_erase_cmd_list;

			addr += cmd->size;
			cmd->count--;

			ret = spi_nor_wait_till_ready(nor);
			if (ret)
				goto destroy_erase_cmd_list;
		}
		list_del(&cmd->list);
		kfree(cmd);
	}

	return 0;

destroy_erase_cmd_list:
	spi_nor_destroy_erase_cmd_list(&erase_list);
	return ret;
}

/*
 * 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)
{
	struct spi_nor *nor = mtd_to_spi_nor(mtd);
	u32 addr, len;
	uint32_t rem;
	int ret;

	dev_dbg(nor->dev, "at 0x%llx, len %lld\n", (long long)instr->addr,
			(long long)instr->len);

	if (spi_nor_has_uniform_erase(nor)) {
		div_u64_rem(instr->len, mtd->erasesize, &rem);
		if (rem)
			return -EINVAL;
	}

	addr = instr->addr;
	len = instr->len;

	ret = spi_nor_lock_and_prep(nor, SPI_NOR_OPS_ERASE);
	if (ret)
		return ret;

	/* whole-chip erase? */
	if (len == mtd->size && !(nor->flags & SNOR_F_NO_OP_CHIP_ERASE)) {
		unsigned long timeout;

		ret = spi_nor_write_enable(nor);
		if (ret)
			goto erase_err;

		ret = spi_nor_erase_chip(nor);
		if (ret)
			goto erase_err;

		/*
		 * Scale the timeout linearly with the size of the flash, with
		 * a minimum calibrated to an old 2MB flash. We could try to
		 * pull these from CFI/SFDP, but these values should be good
		 * enough for now.
		 */
		timeout = max(CHIP_ERASE_2MB_READY_WAIT_JIFFIES,
			      CHIP_ERASE_2MB_READY_WAIT_JIFFIES *
			      (unsigned long)(mtd->size / SZ_2M));
		ret = spi_nor_wait_till_ready_with_timeout(nor, timeout);
		if (ret)
			goto erase_err;

	/* REVISIT in some cases we could speed up erasing large regions
	 * by using SPINOR_OP_SE instead of SPINOR_OP_BE_4K.  We may have set up
	 * to use "small sector erase", but that's not always optimal.
	 */

	/* "sector"-at-a-time erase */
	} else if (spi_nor_has_uniform_erase(nor)) {
		while (len) {
			ret = spi_nor_write_enable(nor);
			if (ret)
				goto erase_err;

			ret = spi_nor_erase_sector(nor, addr);
			if (ret)
				goto erase_err;

			addr += mtd->erasesize;
			len -= mtd->erasesize;

			ret = spi_nor_wait_till_ready(nor);
			if (ret)
				goto erase_err;
		}

	/* erase multiple sectors */
	} else {
		ret = spi_nor_erase_multi_sectors(nor, addr, len);
		if (ret)
			goto erase_err;
	}

	ret = spi_nor_write_disable(nor);

erase_err:
	spi_nor_unlock_and_unprep(nor, SPI_NOR_OPS_ERASE);

	return ret;
}

static void stm_get_locked_range(struct spi_nor *nor, u8 sr, loff_t *ofs,
				 uint64_t *len)
{
	struct mtd_info *mtd = &nor->mtd;
	u8 mask = SR_BP2 | SR_BP1 | SR_BP0;
	int shift = ffs(mask) - 1;
	int pow;

	if (!(sr & mask)) {
		/* No protection */
		*ofs = 0;
		*len = 0;
	} else {
		pow = ((sr & mask) ^ mask) >> shift;
		*len = mtd->size >> pow;
		if (nor->flags & SNOR_F_HAS_SR_TB && sr & SR_TB)
			*ofs = 0;
		else
			*ofs = mtd->size - *len;
	}
}

/*
 * Return 1 if the entire region is locked (if @locked is true) or unlocked (if
 * @locked is false); 0 otherwise
 */
static int stm_check_lock_status_sr(struct spi_nor *nor, loff_t ofs, uint64_t len,
				    u8 sr, bool locked)
{
	loff_t lock_offs;
	uint64_t lock_len;

	if (!len)
		return 1;

	stm_get_locked_range(nor, sr, &lock_offs, &lock_len);

	if (locked)
		/* Requested range is a sub-range of locked range */
		return (ofs + len <= lock_offs + lock_len) && (ofs >= lock_offs);
	else
		/* Requested range does not overlap with locked range */
		return (ofs >= lock_offs + lock_len) || (ofs + len <= lock_offs);
}

static int stm_is_locked_sr(struct spi_nor *nor, loff_t ofs, uint64_t len,
			    u8 sr)
{
	return stm_check_lock_status_sr(nor, ofs, len, sr, true);
}

static int stm_is_unlocked_sr(struct spi_nor *nor, loff_t ofs, uint64_t len,
			      u8 sr)
{
	return stm_check_lock_status_sr(nor, ofs, len, sr, false);
}

/*
 * Lock a region of the flash. Compatible with ST Micro and similar flash.
 * Supports the block protection bits BP{0,1,2} in the status register
 * (SR). Does not support these features found in newer SR bitfields:
 *   - SEC: sector/block protect - only handle SEC=0 (block protect)
 *   - CMP: complement protect - only support CMP=0 (range is not complemented)
 *
 * Support for the following is provided conditionally for some flash:
 *   - TB: top/bottom protect
 *
 * Sample table portion for 8MB flash (Winbond w25q64fw):
 *
 *   SEC  |  TB   |  BP2  |  BP1  |  BP0  |  Prot Length  | Protected Portion
 *  --------------------------------------------------------------------------
 *    X   |   X   |   0   |   0   |   0   |  NONE         | NONE
 *    0   |   0   |   0   |   0   |   1   |  128 KB       | Upper 1/64
 *    0   |   0   |   0   |   1   |   0   |  256 KB       | Upper 1/32
 *    0   |   0   |   0   |   1   |   1   |  512 KB       | Upper 1/16
 *    0   |   0   |   1   |   0   |   0   |  1 MB         | Upper 1/8
 *    0   |   0   |   1   |   0   |   1   |  2 MB         | Upper 1/4
 *    0   |   0   |   1   |   1   |   0   |  4 MB         | Upper 1/2
 *    X   |   X   |   1   |   1   |   1   |  8 MB         | ALL
 *  ------|-------|-------|-------|-------|---------------|-------------------
 *    0   |   1   |   0   |   0   |   1   |  128 KB       | Lower 1/64
 *    0   |   1   |   0   |   1   |   0   |  256 KB       | Lower 1/32
 *    0   |   1   |   0   |   1   |   1   |  512 KB       | Lower 1/16
 *    0   |   1   |   1   |   0   |   0   |  1 MB         | Lower 1/8
 *    0   |   1   |   1   |   0   |   1   |  2 MB         | Lower 1/4
 *    0   |   1   |   1   |   1   |   0   |  4 MB         | Lower 1/2
 *
 * Returns negative on errors, 0 on success.
 */
static int stm_lock(struct spi_nor *nor, loff_t ofs, uint64_t len)
{
	struct mtd_info *mtd = &nor->mtd;
	int ret, status_old, status_new;
	u8 mask = SR_BP2 | SR_BP1 | SR_BP0;
	u8 shift = ffs(mask) - 1, pow, val;
	loff_t lock_len;
	bool can_be_top = true, can_be_bottom = nor->flags & SNOR_F_HAS_SR_TB;
	bool use_top;

	ret = spi_nor_read_sr(nor, nor->bouncebuf);
	if (ret)
		return ret;

	status_old = nor->bouncebuf[0];

	/* If nothing in our range is unlocked, we don't need to do anything */
	if (stm_is_locked_sr(nor, ofs, len, status_old))
		return 0;

	/* If anything below us is unlocked, we can't use 'bottom' protection */
	if (!stm_is_locked_sr(nor, 0, ofs, status_old))
		can_be_bottom = false;

	/* If anything above us is unlocked, we can't use 'top' protection */
	if (!stm_is_locked_sr(nor, ofs + len, mtd->size - (ofs + len),
				status_old))
		can_be_top = false;

	if (!can_be_bottom && !can_be_top)
		return -EINVAL;

	/* Prefer top, if both are valid */
	use_top = can_be_top;

	/* lock_len: length of region that should end up locked */
	if (use_top)
		lock_len = mtd->size - ofs;
	else
		lock_len = ofs + len;

	/*
	 * Need smallest pow such that:
	 *
	 *   1 / (2^pow) <= (len / size)
	 *
	 * so (assuming power-of-2 size) we do:
	 *
	 *   pow = ceil(log2(size / len)) = log2(size) - floor(log2(len))
	 */
	pow = ilog2(mtd->size) - ilog2(lock_len);
	val = mask - (pow << shift);
	if (val & ~mask)
		return -EINVAL;
	/* Don't "lock" with no region! */
	if (!(val & mask))
		return -EINVAL;

	status_new = (status_old & ~mask & ~SR_TB) | val;

	/* Disallow further writes if WP pin is asserted */
	status_new |= SR_SRWD;

	if (!use_top)
		status_new |= SR_TB;

	/* Don't bother if they're the same */
	if (status_new == status_old)
		return 0;

	/* Only modify protection if it will not unlock other areas */
	if ((status_new & mask) < (status_old & mask))
		return -EINVAL;

	return spi_nor_write_sr_and_check(nor, status_new);
}

/*
 * Unlock a region of the flash. See stm_lock() for more info
 *
 * Returns negative on errors, 0 on success.
 */
static int stm_unlock(struct spi_nor *nor, loff_t ofs, uint64_t len)
{
	struct mtd_info *mtd = &nor->mtd;
	int ret, status_old, status_new;
	u8 mask = SR_BP2 | SR_BP1 | SR_BP0;
	u8 shift = ffs(mask) - 1, pow, val;
	loff_t lock_len;
	bool can_be_top = true, can_be_bottom = nor->flags & SNOR_F_HAS_SR_TB;
	bool use_top;

	ret = spi_nor_read_sr(nor, nor->bouncebuf);
	if (ret)
		return ret;

	status_old = nor->bouncebuf[0];

	/* If nothing in our range is locked, we don't need to do anything */
	if (stm_is_unlocked_sr(nor, ofs, len, status_old))
		return 0;

	/* If anything below us is locked, we can't use 'top' protection */
	if (!stm_is_unlocked_sr(nor, 0, ofs, status_old))
		can_be_top = false;

	/* If anything above us is locked, we can't use 'bottom' protection */
	if (!stm_is_unlocked_sr(nor, ofs + len, mtd->size - (ofs + len),
				status_old))
		can_be_bottom = false;

	if (!can_be_bottom && !can_be_top)
		return -EINVAL;

	/* Prefer top, if both are valid */
	use_top = can_be_top;

	/* lock_len: length of region that should remain locked */
	if (use_top)
		lock_len = mtd->size - (ofs + len);
	else
		lock_len = ofs;

	/*
	 * Need largest pow such that:
	 *
	 *   1 / (2^pow) >= (len / size)
	 *
	 * so (assuming power-of-2 size) we do:
	 *
	 *   pow = floor(log2(size / len)) = log2(size) - ceil(log2(len))
	 */
	pow = ilog2(mtd->size) - order_base_2(lock_len);
	if (lock_len == 0) {
		val = 0; /* fully unlocked */
	} else {
		val = mask - (pow << shift);
		/* Some power-of-two sizes are not supported */
		if (val & ~mask)
			return -EINVAL;
	}

	status_new = (status_old & ~mask & ~SR_TB) | val;

	/* Don't protect status register if we're fully unlocked */
	if (lock_len == 0)
		status_new &= ~SR_SRWD;

	if (!use_top)
		status_new |= SR_TB;

	/* Don't bother if they're the same */
	if (status_new == status_old)
		return 0;

	/* Only modify protection if it will not lock other areas */
	if ((status_new & mask) > (status_old & mask))
		return -EINVAL;

	return spi_nor_write_sr_and_check(nor, status_new);
}

/*
 * Check if a region of the flash is (completely) locked. See stm_lock() for
 * more info.
 *
 * Returns 1 if entire region is locked, 0 if any portion is unlocked, and
 * negative on errors.
 */
static int stm_is_locked(struct spi_nor *nor, loff_t ofs, uint64_t len)
{
	int ret;

	ret = spi_nor_read_sr(nor, nor->bouncebuf);
	if (ret)
		return ret;

	return stm_is_locked_sr(nor, ofs, len, nor->bouncebuf[0]);
}

static const struct spi_nor_locking_ops stm_locking_ops = {
	.lock = stm_lock,
	.unlock = stm_unlock,
	.is_locked = stm_is_locked,
};

static int spi_nor_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
{
	struct spi_nor *nor = mtd_to_spi_nor(mtd);
	int ret;

	ret = spi_nor_lock_and_prep(nor, SPI_NOR_OPS_LOCK);
	if (ret)
		return ret;

	ret = nor->params.locking_ops->lock(nor, ofs, len);

	spi_nor_unlock_and_unprep(nor, SPI_NOR_OPS_UNLOCK);
	return ret;
}

static int spi_nor_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
{
	struct spi_nor *nor = mtd_to_spi_nor(mtd);
	int ret;

	ret = spi_nor_lock_and_prep(nor, SPI_NOR_OPS_UNLOCK);
	if (ret)
		return ret;

	ret = nor->params.locking_ops->unlock(nor, ofs, len);

	spi_nor_unlock_and_unprep(nor, SPI_NOR_OPS_LOCK);
	return ret;
}

static int spi_nor_is_locked(struct mtd_info *mtd, loff_t ofs, uint64_t len)
{
	struct spi_nor *nor = mtd_to_spi_nor(mtd);
	int ret;

	ret = spi_nor_lock_and_prep(nor, SPI_NOR_OPS_UNLOCK);
	if (ret)
		return ret;

	ret = nor->params.locking_ops->is_locked(nor, ofs, len);

	spi_nor_unlock_and_unprep(nor, SPI_NOR_OPS_LOCK);
	return ret;
}

/**
 * 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;

	ret = spi_nor_read_sr(nor, nor->bouncebuf);
	if (ret)
		return ret;

	if (nor->bouncebuf[0] & SR_QUAD_EN_MX)
		return 0;

	nor->bouncebuf[0] |= SR_QUAD_EN_MX;

	return spi_nor_write_sr1_and_check(nor, nor->bouncebuf[0]);
}

/**
 * spansion_no_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 not 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_no_read_cr_quad_enable(struct spi_nor *nor)
{
	u8 *sr_cr = nor->bouncebuf;
	int ret;
	u8 sr_written;

	/* Keep the current value of the Status Register. */
	ret = spi_nor_read_sr(nor, sr_cr);
	if (ret)
		return ret;

	sr_cr[1] = SR2_QUAD_EN_BIT1;

	ret = spi_nor_write_sr(nor, sr_cr, 2);
	if (ret)
		return ret;

	sr_written = sr_cr[0];

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

	if (sr_cr[0] != sr_written) {
		dev_err(nor->dev, "SR: Read back test failed\n");
		return -EIO;
	}

	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 = nor->bouncebuf;
	int ret;
	u8 sr_written;

	/* Check current Quad Enable bit value. */
	ret = spi_nor_read_cr(nor, &sr_cr[1]);
	if (ret)
		return ret;

	if (sr_cr[1] & SR2_QUAD_EN_BIT1)
		return 0;

	sr_cr[1] |= SR2_QUAD_EN_BIT1;

	/* Keep the current value of the Status Register. */
	ret = spi_nor_read_sr(nor, sr_cr);
	if (ret)
		return ret;

	ret = spi_nor_write_sr(nor, sr_cr, 2);
	if (ret)
		return ret;

	sr_written = sr_cr[0];

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

	if (sr_written != sr_cr[0]) {
		dev_err(nor->dev, "SR: Read back test failed\n");
		return -EIO;
	}

	sr_written = sr_cr[1];

	/* Read back and check it. */
	ret = spi_nor_read_cr(nor, &sr_cr[1]);
	if (ret)
		return ret;

	if (sr_cr[1] != sr_written) {
		dev_dbg(nor->dev, "CR: Read back test failed\n");
		return -EIO;
	}

	return 0;
}

/**
 * sr2_bit7_quad_enable() - set QE bit in Status Register 2.
 * @nor:	pointer to a 'struct spi_nor'
 *
 * Set the Quad Enable (QE) bit in the Status Register 2.
 *
 * This is one of the procedures to set the QE bit described in the SFDP
 * (JESD216 rev B) specification but no manufacturer using this procedure has
 * been identified yet, hence the name of the function.
 *
 * Return: 0 on success, -errno otherwise.
 */
static int sr2_bit7_quad_enable(struct spi_nor *nor)
{
	u8 *sr2 = nor->bouncebuf;
	int ret;
	u8 sr2_written;

	/* Check current Quad Enable bit value. */
	ret = spi_nor_read_sr2(nor, sr2);
	if (ret)
		return ret;
	if (*sr2 & SR2_QUAD_EN_BIT7)
		return 0;

	/* Update the Quad Enable bit. */
	*sr2 |= SR2_QUAD_EN_BIT7;

	ret = spi_nor_write_sr2(nor, sr2);
	if (ret)
		return ret;

	sr2_written = *sr2;

	/* Read back and check it. */
	ret = spi_nor_read_sr2(nor, sr2);
	if (ret)
		return ret;

	if (*sr2 != sr2_written) {
		dev_dbg(nor->dev, "SR2: Read back test failed\n");
		return -EIO;
	}

	return 0;
}

/* Used when the "_ext_id" is two bytes at most */
#define INFO(_jedec_id, _ext_id, _sector_size, _n_sectors, _flags)	\
		.id = {							\
			((_jedec_id) >> 16) & 0xff,			\
			((_jedec_id) >> 8) & 0xff,			\
			(_jedec_id) & 0xff,				\
			((_ext_id) >> 8) & 0xff,			\
			(_ext_id) & 0xff,				\
			},						\
		.id_len = (!(_jedec_id) ? 0 : (3 + ((_ext_id) ? 2 : 0))),	\
		.sector_size = (_sector_size),				\
		.n_sectors = (_n_sectors),				\
		.page_size = 256,					\
		.flags = (_flags),

#define INFO6(_jedec_id, _ext_id, _sector_size, _n_sectors, _flags)	\
		.id = {							\
			((_jedec_id) >> 16) & 0xff,			\
			((_jedec_id) >> 8) & 0xff,			\
			(_jedec_id) & 0xff,				\
			((_ext_id) >> 16) & 0xff,			\
			((_ext_id) >> 8) & 0xff,			\
			(_ext_id) & 0xff,				\
			},						\
		.id_len = 6,						\
		.sector_size = (_sector_size),				\
		.n_sectors = (_n_sectors),				\
		.page_size = 256,					\
		.flags = (_flags),

#define CAT25_INFO(_sector_size, _n_sectors, _page_size, _addr_width, _flags)	\
		.sector_size = (_sector_size),				\
		.n_sectors = (_n_sectors),				\
		.page_size = (_page_size),				\
		.addr_width = (_addr_width),				\
		.flags = (_flags),

#define S3AN_INFO(_jedec_id, _n_sectors, _page_size)			\
		.id = {							\
			((_jedec_id) >> 16) & 0xff,			\
			((_jedec_id) >> 8) & 0xff,			\
			(_jedec_id) & 0xff				\
			},						\
		.id_len = 3,						\
		.sector_size = (8*_page_size),				\
		.n_sectors = (_n_sectors),				\
		.page_size = _page_size,				\
		.addr_width = 3,					\
		.flags = SPI_NOR_NO_FR | SPI_S3AN,

static int
is25lp256_post_bfpt_fixups(struct spi_nor *nor,
			   const struct sfdp_parameter_header *bfpt_header,
			   const struct sfdp_bfpt *bfpt,
			   struct spi_nor_flash_parameter *params)
{
	/*
	 * IS25LP256 supports 4B opcodes, but the BFPT advertises a
	 * BFPT_DWORD1_ADDRESS_BYTES_3_ONLY address width.
	 * Overwrite the address width advertised by the BFPT.
	 */
	if ((bfpt->dwords[BFPT_DWORD(1)] & BFPT_DWORD1_ADDRESS_BYTES_MASK) ==
		BFPT_DWORD1_ADDRESS_BYTES_3_ONLY)
		nor->addr_width = 4;

	return 0;
}

static struct spi_nor_fixups is25lp256_fixups = {
	.post_bfpt = is25lp256_post_bfpt_fixups,
};

static int
mx25l25635_post_bfpt_fixups(struct spi_nor *nor,
			    const struct sfdp_parameter_header *bfpt_header,
			    const struct sfdp_bfpt *bfpt,
			    struct spi_nor_flash_parameter *params)
{
	/*
	 * MX25L25635F supports 4B opcodes but MX25L25635E does not.
	 * Unfortunately, Macronix has re-used the same JEDEC ID for both
	 * variants which prevents us from defining a new entry in the parts
	 * table.
	 * We need a way to differentiate MX25L25635E and MX25L25635F, and it
	 * seems that the F version advertises support for Fast Read 4-4-4 in
	 * its BFPT table.
	 */
	if (bfpt->dwords[BFPT_DWORD(5)] & BFPT_DWORD5_FAST_READ_4_4_4)
		nor->flags |= SNOR_F_4B_OPCODES;

	return 0;
}

static struct spi_nor_fixups mx25l25635_fixups = {
	.post_bfpt = mx25l25635_post_bfpt_fixups,
};

static void gd25q256_default_init(struct spi_nor *nor)
{
	/*
	 * Some manufacturer like GigaDevice may use different
	 * bit to set QE on different memories, so the MFR can't
	 * indicate the quad_enable method for this case, we need
	 * to set it in the default_init fixup hook.
	 */
	nor->params.quad_enable = macronix_quad_enable;
}

static struct spi_nor_fixups gd25q256_fixups = {
	.default_init = gd25q256_default_init,
};

/* NOTE: double check command sets and memory organization when you add
 * more nor chips.  This current list focusses on newer chips, which
 * have been converging on command sets which including JEDEC ID.
 *
 * All newly added entries should describe *hardware* and should use SECT_4K
 * (or SECT_4K_PMC) if hardware supports erasing 4 KiB sectors. For usage
 * scenarios excluding small sectors there is config option that can be
 * disabled: CONFIG_MTD_SPI_NOR_USE_4K_SECTORS.
 * For historical (and compatibility) reasons (before we got above config) some
 * old entries may be missing 4K flag.
 */
static const struct flash_info spi_nor_ids[] = {
	/* Atmel -- some are (confusingly) marketed as "DataFlash" */
	{ "at25fs010",  INFO(0x1f6601, 0, 32 * 1024,   4, SECT_4K) },
	{ "at25fs040",  INFO(0x1f6604, 0, 64 * 1024,   8, SECT_4K) },

	{ "at25df041a", INFO(0x1f4401, 0, 64 * 1024,   8, SECT_4K) },
	{ "at25df321",  INFO(0x1f4700, 0, 64 * 1024,  64, SECT_4K) },
	{ "at25df321a", INFO(0x1f4701, 0, 64 * 1024,  64, SECT_4K) },
	{ "at25df641",  INFO(0x1f4800, 0, 64 * 1024, 128, SECT_4K) },

	{ "at26f004",   INFO(0x1f0400, 0, 64 * 1024,  8, SECT_4K) },
	{ "at26df081a", INFO(0x1f4501, 0, 64 * 1024, 16, SECT_4K) },
	{ "at26df161a", INFO(0x1f4601, 0, 64 * 1024, 32, SECT_4K) },
	{ "at26df321",  INFO(0x1f4700, 0, 64 * 1024, 64, SECT_4K) },

	{ "at45db081d", INFO(0x1f2500, 0, 64 * 1024, 16, SECT_4K) },

	/* EON -- en25xxx */
	{ "en25f32",    INFO(0x1c3116, 0, 64 * 1024,   64, SECT_4K) },
	{ "en25p32",    INFO(0x1c2016, 0, 64 * 1024,   64, 0) },
	{ "en25q32b",   INFO(0x1c3016, 0, 64 * 1024,   64, 0) },
	{ "en25p64",    INFO(0x1c2017, 0, 64 * 1024,  128, 0) },
	{ "en25q64",    INFO(0x1c3017, 0, 64 * 1024,  128, SECT_4K) },
	{ "en25q80a",   INFO(0x1c3014, 0, 64 * 1024,   16,
			SECT_4K | SPI_NOR_DUAL_READ) },
	{ "en25qh16",   INFO(0x1c7015, 0, 64 * 1024,   32,
			SECT_4K | SPI_NOR_DUAL_READ) },
	{ "en25qh32",   INFO(0x1c7016, 0, 64 * 1024,   64, 0) },
	{ "en25qh64",   INFO(0x1c7017, 0, 64 * 1024,  128,
			SECT_4K | SPI_NOR_DUAL_READ) },
	{ "en25qh128",  INFO(0x1c7018, 0, 64 * 1024,  256, 0) },
	{ "en25qh256",  INFO(0x1c7019, 0, 64 * 1024,  512, 0) },
	{ "en25s64",	INFO(0x1c3817, 0, 64 * 1024,  128, SECT_4K) },

	/* ESMT */
	{ "f25l32pa", INFO(0x8c2016, 0, 64 * 1024, 64, SECT_4K | SPI_NOR_HAS_LOCK) },
	{ "f25l32qa", INFO(0x8c4116, 0, 64 * 1024, 64, SECT_4K | SPI_NOR_HAS_LOCK) },
	{ "f25l64qa", INFO(0x8c4117, 0, 64 * 1024, 128, SECT_4K | SPI_NOR_HAS_LOCK) },

	/* Everspin */
	{ "mr25h128", CAT25_INFO( 16 * 1024, 1, 256, 2, SPI_NOR_NO_ERASE | SPI_NOR_NO_FR) },
	{ "mr25h256", CAT25_INFO( 32 * 1024, 1, 256, 2, SPI_NOR_NO_ERASE | SPI_NOR_NO_FR) },
	{ "mr25h10",  CAT25_INFO(128 * 1024, 1, 256, 3, SPI_NOR_NO_ERASE | SPI_NOR_NO_FR) },
	{ "mr25h40",  CAT25_INFO(512 * 1024, 1, 256, 3, SPI_NOR_NO_ERASE | SPI_NOR_NO_FR) },

	/* Fujitsu */
	{ "mb85rs1mt", INFO(0x047f27, 0, 128 * 1024, 1, SPI_NOR_NO_ERASE) },

	/* GigaDevice */
	{
		"gd25q16", INFO(0xc84015, 0, 64 * 1024,  32,
			SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ |
			SPI_NOR_HAS_LOCK | SPI_NOR_HAS_TB)
	},
	{
		"gd25q32", INFO(0xc84016, 0, 64 * 1024,  64,
			SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ |
			SPI_NOR_HAS_LOCK | SPI_NOR_HAS_TB)
	},
	{
		"gd25lq32", INFO(0xc86016, 0, 64 * 1024, 64,
			SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ |
			SPI_NOR_HAS_LOCK | SPI_NOR_HAS_TB)
	},
	{
		"gd25q64", INFO(0xc84017, 0, 64 * 1024, 128,
			SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ |
			SPI_NOR_HAS_LOCK | SPI_NOR_HAS_TB)
	},
	{
		"gd25lq64c", INFO(0xc86017, 0, 64 * 1024, 128,
			SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ |
			SPI_NOR_HAS_LOCK | SPI_NOR_HAS_TB)
	},
	{
		"gd25q128", INFO(0xc84018, 0, 64 * 1024, 256,
			SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ |
			SPI_NOR_HAS_LOCK | SPI_NOR_HAS_TB)
	},
	{
		"gd25q256", INFO(0xc84019, 0, 64 * 1024, 512,
			SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ |
			SPI_NOR_4B_OPCODES | SPI_NOR_HAS_LOCK | SPI_NOR_HAS_TB)
			.fixups = &gd25q256_fixups,
	},

	/* Intel/Numonyx -- xxxs33b */
	{ "160s33b",  INFO(0x898911, 0, 64 * 1024,  32, 0) },
	{ "320s33b",  INFO(0x898912, 0, 64 * 1024,  64, 0) },
	{ "640s33b",  INFO(0x898913, 0, 64 * 1024, 128, 0) },

	/* ISSI */
	{ "is25cd512",  INFO(0x7f9d20, 0, 32 * 1024,   2, SECT_4K) },
	{ "is25lq040b", INFO(0x9d4013, 0, 64 * 1024,   8,
			SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
	{ "is25lp016d", INFO(0x9d6015, 0, 64 * 1024,  32,
			SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
	{ "is25lp080d", INFO(0x9d6014, 0, 64 * 1024,  16,
			SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
	{ "is25lp032",  INFO(0x9d6016, 0, 64 * 1024,  64,
			SECT_4K | SPI_NOR_DUAL_READ) },
	{ "is25lp064",  INFO(0x9d6017, 0, 64 * 1024, 128,
			SECT_4K | SPI_NOR_DUAL_READ) },
	{ "is25lp128",  INFO(0x9d6018, 0, 64 * 1024, 256,
			SECT_4K | SPI_NOR_DUAL_READ) },
	{ "is25lp256",  INFO(0x9d6019, 0, 64 * 1024, 512,
			SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ |
			SPI_NOR_4B_OPCODES)
			.fixups = &is25lp256_fixups },
	{ "is25wp032",  INFO(0x9d7016, 0, 64 * 1024,  64,
			SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
	{ "is25wp064",  INFO(0x9d7017, 0, 64 * 1024, 128,
			SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
	{ "is25wp128",  INFO(0x9d7018, 0, 64 * 1024, 256,
			SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },

	/* Macronix */
	{ "mx25l512e",   INFO(0xc22010, 0, 64 * 1024,   1, SECT_4K) },
	{ "mx25l2005a",  INFO(0xc22012, 0, 64 * 1024,   4, SECT_4K) },
	{ "mx25l4005a",  INFO(0xc22013, 0, 64 * 1024,   8, SECT_4K) },
	{ "mx25l8005",   INFO(0xc22014, 0, 64 * 1024,  16, 0) },
	{ "mx25l1606e",  INFO(0xc22015, 0, 64 * 1024,  32, SECT_4K) },
	{ "mx25l3205d",  INFO(0xc22016, 0, 64 * 1024,  64, SECT_4K) },
	{ "mx25l3255e",  INFO(0xc29e16, 0, 64 * 1024,  64, SECT_4K) },
	{ "mx25l6405d",  INFO(0xc22017, 0, 64 * 1024, 128, SECT_4K) },
	{ "mx25u2033e",  INFO(0xc22532, 0, 64 * 1024,   4, SECT_4K) },
	{ "mx25u3235f",	 INFO(0xc22536, 0, 64 * 1024,  64,
			 SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
	{ "mx25u4035",   INFO(0xc22533, 0, 64 * 1024,   8, SECT_4K) },
	{ "mx25u8035",   INFO(0xc22534, 0, 64 * 1024,  16, SECT_4K) },
	{ "mx25u6435f",  INFO(0xc22537, 0, 64 * 1024, 128, SECT_4K) },
	{ "mx25l12805d", INFO(0xc22018, 0, 64 * 1024, 256, 0) },
	{ "mx25l12855e", INFO(0xc22618, 0, 64 * 1024, 256, 0) },
	{ "mx25u12835f", INFO(0xc22538, 0, 64 * 1024, 256,
			 SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
	{ "mx25l25635e", INFO(0xc22019, 0, 64 * 1024, 512,
			 SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ)
			 .fixups = &mx25l25635_fixups },
	{ "mx25u25635f", INFO(0xc22539, 0, 64 * 1024, 512, SECT_4K | SPI_NOR_4B_OPCODES) },
	{ "mx25v8035f",  INFO(0xc22314, 0, 64 * 1024,  16,
			 SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
	{ "mx25l25655e", INFO(0xc22619, 0, 64 * 1024, 512, 0) },
	{ "mx66l51235l", INFO(0xc2201a, 0, 64 * 1024, 1024, SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ | SPI_NOR_4B_OPCODES) },
	{ "mx66u51235f", INFO(0xc2253a, 0, 64 * 1024, 1024, SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ | SPI_NOR_4B_OPCODES) },
	{ "mx66l1g45g",  INFO(0xc2201b, 0, 64 * 1024, 2048, SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
	{ "mx66l1g55g",  INFO(0xc2261b, 0, 64 * 1024, 2048, SPI_NOR_QUAD_READ) },

	/* Micron <--> ST Micro */
	{ "n25q016a",	 INFO(0x20bb15, 0, 64 * 1024,   32, SECT_4K | SPI_NOR_QUAD_READ) },
	{ "n25q032",	 INFO(0x20ba16, 0, 64 * 1024,   64, SPI_NOR_QUAD_READ) },
	{ "n25q032a",	 INFO(0x20bb16, 0, 64 * 1024,   64, SPI_NOR_QUAD_READ) },
	{ "n25q064",     INFO(0x20ba17, 0, 64 * 1024,  128, SECT_4K | SPI_NOR_QUAD_READ) },
	{ "n25q064a",    INFO(0x20bb17, 0, 64 * 1024,  128, SECT_4K | SPI_NOR_QUAD_READ) },
	{ "n25q128a11",  INFO(0x20bb18, 0, 64 * 1024,  256, SECT_4K | SPI_NOR_QUAD_READ) },
	{ "n25q128a13",  INFO(0x20ba18, 0, 64 * 1024,  256, SECT_4K | SPI_NOR_QUAD_READ) },
	{ "n25q256a",    INFO(0x20ba19, 0, 64 * 1024,  512, SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
	{ "n25q256ax1",  INFO(0x20bb19, 0, 64 * 1024,  512, SECT_4K | SPI_NOR_QUAD_READ) },
	{ "n25q512ax3",  INFO(0x20ba20, 0, 64 * 1024, 1024, SECT_4K | USE_FSR | SPI_NOR_QUAD_READ) },
	{ "n25q00",      INFO(0x20ba21, 0, 64 * 1024, 2048, SECT_4K | USE_FSR | SPI_NOR_QUAD_READ | NO_CHIP_ERASE) },
	{ "n25q00a",     INFO(0x20bb21, 0, 64 * 1024, 2048, SECT_4K | USE_FSR | SPI_NOR_QUAD_READ | NO_CHIP_ERASE) },
	{ "mt25ql02g",   INFO(0x20ba22, 0, 64 * 1024, 4096,
			      SECT_4K | USE_FSR | SPI_NOR_QUAD_READ |
			      NO_CHIP_ERASE) },
	{ "mt25qu512a (n25q512a)", INFO(0x20bb20, 0, 64 * 1024, 1024,
					SECT_4K | USE_FSR | SPI_NOR_DUAL_READ |
					SPI_NOR_QUAD_READ |
					SPI_NOR_4B_OPCODES) },
	{ "mt25qu02g",   INFO(0x20bb22, 0, 64 * 1024, 4096, SECT_4K | USE_FSR | SPI_NOR_QUAD_READ | NO_CHIP_ERASE) },

	/* Micron */
	{
		"mt35xu512aba", INFO(0x2c5b1a, 0, 128 * 1024, 512,
			SECT_4K | USE_FSR | SPI_NOR_OCTAL_READ |
			SPI_NOR_4B_OPCODES)
	},
	{ "mt35xu02g",  INFO(0x2c5b1c, 0, 128 * 1024, 2048,
			     SECT_4K | USE_FSR | SPI_NOR_OCTAL_READ |
			     SPI_NOR_4B_OPCODES) },

	/* PMC */
	{ "pm25lv512",   INFO(0,        0, 32 * 1024,    2, SECT_4K_PMC) },
	{ "pm25lv010",   INFO(0,        0, 32 * 1024,    4, SECT_4K_PMC) },
	{ "pm25lq032",   INFO(0x7f9d46, 0, 64 * 1024,   64, SECT_4K) },

	/* Spansion/Cypress -- single (large) sector size only, at least
	 * for the chips listed here (without boot sectors).
	 */
	{ "s25sl032p",  INFO(0x010215, 0x4d00,  64 * 1024,  64, SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
	{ "s25sl064p",  INFO(0x010216, 0x4d00,  64 * 1024, 128, SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
	{ "s25fl128s0", INFO6(0x012018, 0x4d0080, 256 * 1024, 64,
			SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ | USE_CLSR) },
	{ "s25fl128s1", INFO6(0x012018, 0x4d0180, 64 * 1024, 256,
			SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ | USE_CLSR) },
	{ "s25fl256s0", INFO(0x010219, 0x4d00, 256 * 1024, 128, USE_CLSR) },
	{ "s25fl256s1", INFO(0x010219, 0x4d01,  64 * 1024, 512, SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ | USE_CLSR) },
	{ "s25fl512s",  INFO6(0x010220, 0x4d0080, 256 * 1024, 256,
			SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ |
			SPI_NOR_HAS_LOCK | USE_CLSR) },
	{ "s25fs512s",  INFO6(0x010220, 0x4d0081, 256 * 1024, 256, SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ | USE_CLSR) },
	{ "s70fl01gs",  INFO(0x010221, 0x4d00, 256 * 1024, 256, 0) },
	{ "s25sl12800", INFO(0x012018, 0x0300, 256 * 1024,  64, 0) },
	{ "s25sl12801", INFO(0x012018, 0x0301,  64 * 1024, 256, 0) },
	{ "s25fl129p0", INFO(0x012018, 0x4d00, 256 * 1024,  64, SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ | USE_CLSR) },
	{ "s25fl129p1", INFO(0x012018, 0x4d01,  64 * 1024, 256, SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ | USE_CLSR) },
	{ "s25sl004a",  INFO(0x010212,      0,  64 * 1024,   8, 0) },
	{ "s25sl008a",  INFO(0x010213,      0,  64 * 1024,  16, 0) },
	{ "s25sl016a",  INFO(0x010214,      0,  64 * 1024,  32, 0) },
	{ "s25sl032a",  INFO(0x010215,      0,  64 * 1024,  64, 0) },
	{ "s25sl064a",  INFO(0x010216,      0,  64 * 1024, 128, 0) },
	{ "s25fl004k",  INFO(0xef4013,      0,  64 * 1024,   8, SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
	{ "s25fl008k",  INFO(0xef4014,      0,  64 * 1024,  16, SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
	{ "s25fl016k",  INFO(0xef4015,      0,  64 * 1024,  32, SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
	{ "s25fl064k",  INFO(0xef4017,      0,  64 * 1024, 128, SECT_4K) },
	{ "s25fl116k",  INFO(0x014015,      0,  64 * 1024,  32, SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
	{ "s25fl132k",  INFO(0x014016,      0,  64 * 1024,  64, SECT_4K) },
	{ "s25fl164k",  INFO(0x014017,      0,  64 * 1024, 128, SECT_4K) },
	{ "s25fl204k",  INFO(0x014013,      0,  64 * 1024,   8, SECT_4K | SPI_NOR_DUAL_READ) },
	{ "s25fl208k",  INFO(0x014014,      0,  64 * 1024,  16, SECT_4K | SPI_NOR_DUAL_READ) },
	{ "s25fl064l",  INFO(0x016017,      0,  64 * 1024, 128, SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ | SPI_NOR_4B_OPCODES) },
	{ "s25fl128l",  INFO(0x016018,      0,  64 * 1024, 256, SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ | SPI_NOR_4B_OPCODES) },
	{ "s25fl256l",  INFO(0x016019,      0,  64 * 1024, 512, SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ | SPI_NOR_4B_OPCODES) },

	/* SST -- large erase sizes are "overlays", "sectors" are 4K */
	{ "sst25vf040b", INFO(0xbf258d, 0, 64 * 1024,  8, SECT_4K | SST_WRITE) },
	{ "sst25vf080b", INFO(0xbf258e, 0, 64 * 1024, 16, SECT_4K | SST_WRITE) },
	{ "sst25vf016b", INFO(0xbf2541, 0, 64 * 1024, 32, SECT_4K | SST_WRITE) },
	{ "sst25vf032b", INFO(0xbf254a, 0, 64 * 1024, 64, SECT_4K | SST_WRITE) },
	{ "sst25vf064c", INFO(0xbf254b, 0, 64 * 1024, 128, SECT_4K) },
	{ "sst25wf512",  INFO(0xbf2501, 0, 64 * 1024,  1, SECT_4K | SST_WRITE) },
	{ "sst25wf010",  INFO(0xbf2502, 0, 64 * 1024,  2, SECT_4K | SST_WRITE) },
	{ "sst25wf020",  INFO(0xbf2503, 0, 64 * 1024,  4, SECT_4K | SST_WRITE) },
	{ "sst25wf020a", INFO(0x621612, 0, 64 * 1024,  4, SECT_4K) },
	{ "sst25wf040b", INFO(0x621613, 0, 64 * 1024,  8, SECT_4K) },
	{ "sst25wf040",  INFO(0xbf2504, 0, 64 * 1024,  8, SECT_4K | SST_WRITE) },
	{ "sst25wf080",  INFO(0xbf2505, 0, 64 * 1024, 16, SECT_4K | SST_WRITE) },
	{ "sst26wf016b", INFO(0xbf2651, 0, 64 * 1024, 32, SECT_4K |
			      SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
	{ "sst26vf064b", INFO(0xbf2643, 0, 64 * 1024, 128, SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },

	/* ST Microelectronics -- newer production may have feature updates */
	{ "m25p05",  INFO(0x202010,  0,  32 * 1024,   2, 0) },
	{ "m25p10",  INFO(0x202011,  0,  32 * 1024,   4, 0) },
	{ "m25p20",  INFO(0x202012,  0,  64 * 1024,   4, 0) },
	{ "m25p40",  INFO(0x202013,  0,  64 * 1024,   8, 0) },
	{ "m25p80",  INFO(0x202014,  0,  64 * 1024,  16, 0) },
	{ "m25p16",  INFO(0x202015,  0,  64 * 1024,  32, 0) },
	{ "m25p32",  INFO(0x202016,  0,  64 * 1024,  64, 0) },
	{ "m25p64",  INFO(0x202017,  0,  64 * 1024, 128, 0) },
	{ "m25p128", INFO(0x202018,  0, 256 * 1024,  64, 0) },

	{ "m25p05-nonjedec",  INFO(0, 0,  32 * 1024,   2, 0) },
	{ "m25p10-nonjedec",  INFO(0, 0,  32 * 1024,   4, 0) },
	{ "m25p20-nonjedec",  INFO(0, 0,  64 * 1024,   4, 0) },
	{ "m25p40-nonjedec",  INFO(0, 0,  64 * 1024,   8, 0) },
	{ "m25p80-nonjedec",  INFO(0, 0,  64 * 1024,  16, 0) },
	{ "m25p16-nonjedec",  INFO(0, 0,  64 * 1024,  32, 0) },
	{ "m25p32-nonjedec",  INFO(0, 0,  64 * 1024,  64, 0) },
	{ "m25p64-nonjedec",  INFO(0, 0,  64 * 1024, 128, 0) },
	{ "m25p128-nonjedec", INFO(0, 0, 256 * 1024,  64, 0) },

	{ "m45pe10", INFO(0x204011,  0, 64 * 1024,    2, 0) },
	{ "m45pe80", INFO(0x204014,  0, 64 * 1024,   16, 0) },
	{ "m45pe16", INFO(0x204015,  0, 64 * 1024,   32, 0) },

	{ "m25pe20", INFO(0x208012,  0, 64 * 1024,  4,       0) },
	{ "m25pe80", INFO(0x208014,  0, 64 * 1024, 16,       0) },
	{ "m25pe16", INFO(0x208015,  0, 64 * 1024, 32, SECT_4K) },

	{ "m25px16",    INFO(0x207115,  0, 64 * 1024, 32, SECT_4K) },
	{ "m25px32",    INFO(0x207116,  0, 64 * 1024, 64, SECT_4K) },
	{ "m25px32-s0", INFO(0x207316,  0, 64 * 1024, 64, SECT_4K) },
	{ "m25px32-s1", INFO(0x206316,  0, 64 * 1024, 64, SECT_4K) },
	{ "m25px64",    INFO(0x207117,  0, 64 * 1024, 128, 0) },
	{ "m25px80",    INFO(0x207114,  0, 64 * 1024, 16, 0) },

	/* Winbond -- w25x "blocks" are 64K, "sectors" are 4KiB */
	{ "w25x05", INFO(0xef3010, 0, 64 * 1024,  1,  SECT_4K) },
	{ "w25x10", INFO(0xef3011, 0, 64 * 1024,  2,  SECT_4K) },
	{ "w25x20", INFO(0xef3012, 0, 64 * 1024,  4,  SECT_4K) },
	{ "w25x40", INFO(0xef3013, 0, 64 * 1024,  8,  SECT_4K) },
	{ "w25x80", INFO(0xef3014, 0, 64 * 1024,  16, SECT_4K) },
	{ "w25x16", INFO(0xef3015, 0, 64 * 1024,  32, SECT_4K) },
	{
		"w25q16dw", INFO(0xef6015, 0, 64 * 1024,  32,
			SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ |
			SPI_NOR_HAS_LOCK | SPI_NOR_HAS_TB)
	},
	{ "w25x32", INFO(0xef3016, 0, 64 * 1024,  64, SECT_4K) },
	{
		"w25q16jv-im/jm", INFO(0xef7015, 0, 64 * 1024,  32,
			SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ |
			SPI_NOR_HAS_LOCK | SPI_NOR_HAS_TB)
	},
	{ "w25q20cl", INFO(0xef4012, 0, 64 * 1024,  4, SECT_4K) },
	{ "w25q20bw", INFO(0xef5012, 0, 64 * 1024,  4, SECT_4K) },
	{ "w25q20ew", INFO(0xef6012, 0, 64 * 1024,  4, SECT_4K) },
	{ "w25q32", INFO(0xef4016, 0, 64 * 1024,  64, SECT_4K) },
	{
		"w25q32dw", INFO(0xef6016, 0, 64 * 1024,  64,
			SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ |
			SPI_NOR_HAS_LOCK | SPI_NOR_HAS_TB)
	},
	{
		"w25q32jv", INFO(0xef7016, 0, 64 * 1024,  64,
			SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ |
			SPI_NOR_HAS_LOCK | SPI_NOR_HAS_TB)
	},
	{ "w25x64", INFO(0xef3017, 0, 64 * 1024, 128, SECT_4K) },
	{ "w25q64", INFO(0xef4017, 0, 64 * 1024, 128, SECT_4K) },
	{
		"w25q64dw", INFO(0xef6017, 0, 64 * 1024, 128,
			SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ |
			SPI_NOR_HAS_LOCK | SPI_NOR_HAS_TB)
	},
	{
		"w25q128fw", INFO(0xef6018, 0, 64 * 1024, 256,
			SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ |
			SPI_NOR_HAS_LOCK | SPI_NOR_HAS_TB)
	},
	{
		"w25q128jv", INFO(0xef7018, 0, 64 * 1024, 256,
			SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ |
			SPI_NOR_HAS_LOCK | SPI_NOR_HAS_TB)
	},
	{ "w25q80", INFO(0xef5014, 0, 64 * 1024,  16, SECT_4K) },
	{ "w25q80bl", INFO(0xef4014, 0, 64 * 1024,  16, SECT_4K) },
	{ "w25q128", INFO(0xef4018, 0, 64 * 1024, 256, SECT_4K) },
	{ "w25q256", INFO(0xef4019, 0, 64 * 1024, 512, SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
	{ "w25q256jvm", INFO(0xef7019, 0, 64 * 1024, 512,
			     SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
	{ "w25m512jv", INFO(0xef7119, 0, 64 * 1024, 1024,
			SECT_4K | SPI_NOR_QUAD_READ | SPI_NOR_DUAL_READ) },

	/* Catalyst / On Semiconductor -- non-JEDEC */
	{ "cat25c11", CAT25_INFO(  16, 8, 16, 1, SPI_NOR_NO_ERASE | SPI_NOR_NO_FR) },
	{ "cat25c03", CAT25_INFO(  32, 8, 16, 2, SPI_NOR_NO_ERASE | SPI_NOR_NO_FR) },
	{ "cat25c09", CAT25_INFO( 128, 8, 32, 2, SPI_NOR_NO_ERASE | SPI_NOR_NO_FR) },
	{ "cat25c17", CAT25_INFO( 256, 8, 32, 2, SPI_NOR_NO_ERASE | SPI_NOR_NO_FR) },
	{ "cat25128", CAT25_INFO(2048, 8, 64, 2, SPI_NOR_NO_ERASE | SPI_NOR_NO_FR) },

	/* Xilinx S3AN Internal Flash */
	{ "3S50AN", S3AN_INFO(0x1f2200, 64, 264) },
	{ "3S200AN", S3AN_INFO(0x1f2400, 256, 264) },
	{ "3S400AN", S3AN_INFO(0x1f2400, 256, 264) },
	{ "3S700AN", S3AN_INFO(0x1f2500, 512, 264) },
	{ "3S1400AN", S3AN_INFO(0x1f2600, 512, 528) },

	/* XMC (Wuhan Xinxin Semiconductor Manufacturing Corp.) */
	{ "XM25QH64A", INFO(0x207017, 0, 64 * 1024, 128, SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
	{ "XM25QH128A", INFO(0x207018, 0, 64 * 1024, 256, SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
	{ },
};

static const struct flash_info *spi_nor_read_id(struct spi_nor *nor)
{
	int			tmp;
	u8			*id = nor->bouncebuf;
	const struct flash_info	*info;

	if (nor->spimem) {
		struct spi_mem_op op =
			SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_RDID, 1),
				   SPI_MEM_OP_NO_ADDR,
				   SPI_MEM_OP_NO_DUMMY,
				   SPI_MEM_OP_DATA_IN(SPI_NOR_MAX_ID_LEN, id, 1));

		tmp = spi_mem_exec_op(nor->spimem, &op);
	} else {
		tmp = nor->controller_ops->read_reg(nor, SPINOR_OP_RDID, id,
						    SPI_NOR_MAX_ID_LEN);
	}
	if (tmp) {
		dev_dbg(nor->dev, "error %d reading JEDEC ID\n", tmp);
		return ERR_PTR(tmp);
	}

	for (tmp = 0; tmp < ARRAY_SIZE(spi_nor_ids) - 1; tmp++) {
		info = &spi_nor_ids[tmp];
		if (info->id_len) {
			if (!memcmp(info->id, id, info->id_len))
				return &spi_nor_ids[tmp];
		}
	}
	dev_err(nor->dev, "unrecognized JEDEC id bytes: %*ph\n",
		SPI_NOR_MAX_ID_LEN, id);
	return ERR_PTR(-ENODEV);
}

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);
	ssize_t ret;

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

	ret = spi_nor_lock_and_prep(nor, SPI_NOR_OPS_READ);
	if (ret)
		return ret;

	while (len) {
		loff_t addr = from;

		addr = spi_nor_convert_addr(nor, addr);

		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;

		WARN_ON(ret > len);
		*retlen += ret;
		buf += ret;
		from += ret;
		len -= ret;
	}
	ret = 0;

read_err:
	spi_nor_unlock_and_unprep(nor, SPI_NOR_OPS_READ);
	return ret;
}

static int sst_write(struct mtd_info *mtd, loff_t to, size_t len,
		size_t *retlen, const u_char *buf)
{
	struct spi_nor *nor = mtd_to_spi_nor(mtd);
	size_t actual = 0;
	int ret;

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

	ret = spi_nor_lock_and_prep(nor, SPI_NOR_OPS_WRITE);
	if (ret)
		return ret;

	ret = spi_nor_write_enable(nor);
	if (ret)
		goto out;

	nor->sst_write_second = false;

	/* Start write from odd address. */
	if (to % 2) {
		nor->program_opcode = SPINOR_OP_BP;

		/* write one byte. */
		ret = spi_nor_write_data(nor, to, 1, buf);
		if (ret < 0)
			goto out;
		WARN(ret != 1, "While writing 1 byte written %i bytes\n", ret);
		ret = spi_nor_wait_till_ready(nor);
		if (ret)
			goto out;

		to++;
		actual++;
	}

	/* Write out most of the data here. */
	for (; actual < len - 1; actual += 2) {
		nor->program_opcode = SPINOR_OP_AAI_WP;

		/* write two bytes. */
		ret = spi_nor_write_data(nor, to, 2, buf + actual);
		if (ret < 0)
			goto out;
		WARN(ret != 2, "While writing 2 bytes written %i bytes\n", ret);
		ret = spi_nor_wait_till_ready(nor);
		if (ret)
			goto out;
		to += 2;
		nor->sst_write_second = true;
	}
	nor->sst_write_second = false;

	ret = spi_nor_write_disable(nor);
	if (ret)
		goto out;

	ret = spi_nor_wait_till_ready(nor);
	if (ret)
		goto out;

	/* Write out trailing byte if it exists. */
	if (actual != len) {
		ret = spi_nor_write_enable(nor);
		if (ret)
			goto out;

		nor->program_opcode = SPINOR_OP_BP;
		ret = spi_nor_write_data(nor, to, 1, buf + actual);
		if (ret < 0)
			goto out;
		WARN(ret != 1, "While writing 1 byte written %i bytes\n", ret);
		ret = spi_nor_wait_till_ready(nor);
		if (ret)
			goto out;

		actual += 1;

		ret = spi_nor_write_disable(nor);
	}
out:
	*retlen += actual;
	spi_nor_unlock_and_unprep(nor, SPI_NOR_OPS_WRITE);
	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)
{
	struct spi_nor *nor = mtd_to_spi_nor(mtd);
	size_t page_offset, page_remain, i;
	ssize_t ret;

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

	ret = spi_nor_lock_and_prep(nor, SPI_NOR_OPS_WRITE);
	if (ret)
		return ret;

	for (i = 0; i < len; ) {
		ssize_t written;
		loff_t addr = to + i;

		/*
		 * If page_size is a power of two, the offset can be quickly
		 * calculated with an AND operation. On the other cases we
		 * need to do a modulus operation (more expensive).
		 * Power of two numbers have only one bit set and we can use
		 * the instruction hweight32 to detect if we need to do a
		 * modulus (do_div()) or not.
		 */
		if (hweight32(nor->page_size) == 1) {
			page_offset = addr & (nor->page_size - 1);
		} else {
			uint64_t aux = addr;

			page_offset = do_div(aux, nor->page_size);
		}
		/* the size of data remaining on the first page */
		page_remain = min_t(size_t,
				    nor->page_size - page_offset, len - i);

		addr = spi_nor_convert_addr(nor, addr);

		ret = spi_nor_write_enable(nor);
		if (ret)
			goto write_err;

		ret = spi_nor_write_data(nor, addr, page_remain, buf + i);
		if (ret < 0)
			goto write_err;
		written = ret;

		ret = spi_nor_wait_till_ready(nor);
		if (ret)
			goto write_err;
		*retlen += written;
		i += written;
	}

write_err:
	spi_nor_unlock_and_unprep(nor, SPI_NOR_OPS_WRITE);
	return ret;
}

static int spi_nor_check(struct spi_nor *nor)
{
	if (!nor->dev ||
	    (!nor->spimem && nor->controller_ops &&
	    (!nor->controller_ops->read ||
	     !nor->controller_ops->write ||
	     !nor->controller_ops->read_reg ||
	     !nor->controller_ops->write_reg))) {
		pr_err("spi-nor: please fill all the necessary fields!\n");
		return -EINVAL;
	}

	return 0;
}

static int s3an_nor_setup(struct spi_nor *nor,
			  const struct spi_nor_hwcaps *hwcaps)
{
	int ret;

	ret = spi_nor_xread_sr(nor, nor->bouncebuf);
	if (ret)
		return ret;

	nor->erase_opcode = SPINOR_OP_XSE;
	nor->program_opcode = SPINOR_OP_XPP;
	nor->read_opcode = SPINOR_OP_READ;
	nor->flags |= SNOR_F_NO_OP_CHIP_ERASE;

	/*
	 * This flashes have a page size of 264 or 528 bytes (known as
	 * Default addressing mode). It can be changed to a more standard
	 * Power of two mode where the page size is 256/512. This comes
	 * with a price: there is 3% less of space, the data is corrupted
	 * and the page size cannot be changed back to default addressing
	 * mode.
	 *
	 * The current addressing mode can be read from the XRDSR register
	 * and should not be changed, because is a destructive operation.
	 */
	if (nor->bouncebuf[0] & XSR_PAGESIZE) {
		/* Flash in Power of 2 mode */
		nor->page_size = (nor->page_size == 264) ? 256 : 512;
		nor->mtd.writebufsize = nor->page_size;
		nor->mtd.size = 8 * nor->page_size * nor->info->n_sectors;
		nor->mtd.erasesize = 8 * nor->page_size;
	} else {
		/* Flash in Default addressing mode */
		nor->params.convert_addr = s3an_convert_addr;
		nor->mtd.erasesize = nor->info->sector_size;
	}

	return 0;
}

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 void
spi_nor_set_pp_settings(struct spi_nor_pp_command *pp,
			u8 opcode,
			enum spi_nor_protocol proto)
{
	pp->opcode = opcode;
	pp->proto = proto;
}

static int spi_nor_hwcaps2cmd(u32 hwcaps, const int table[][2], size_t size)
{
	size_t i;

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

	return -EINVAL;
}

static int spi_nor_hwcaps_read2cmd(u32 hwcaps)
{
	static const int hwcaps_read2cmd[][2] = {
		{ SNOR_HWCAPS_READ,		SNOR_CMD_READ },
		{ SNOR_HWCAPS_READ_FAST,	SNOR_CMD_READ_FAST },
		{ SNOR_HWCAPS_READ_1_1_1_DTR,	SNOR_CMD_READ_1_1_1_DTR },
		{ SNOR_HWCAPS_READ_1_1_2,	SNOR_CMD_READ_1_1_2 },
		{ SNOR_HWCAPS_READ_1_2_2,	SNOR_CMD_READ_1_2_2 },
		{ SNOR_HWCAPS_READ_2_2_2,	SNOR_CMD_READ_2_2_2 },
		{ SNOR_HWCAPS_READ_1_2_2_DTR,	SNOR_CMD_READ_1_2_2_DTR },
		{ SNOR_HWCAPS_READ_1_1_4,	SNOR_CMD_READ_1_1_4 },
		{ SNOR_HWCAPS_READ_1_4_4,	SNOR_CMD_READ_1_4_4 },
		{ SNOR_HWCAPS_READ_4_4_4,	SNOR_CMD_READ_4_4_4 },
		{ SNOR_HWCAPS_READ_1_4_4_DTR,	SNOR_CMD_READ_1_4_4_DTR },
		{ SNOR_HWCAPS_READ_1_1_8,	SNOR_CMD_READ_1_1_8 },
		{ SNOR_HWCAPS_READ_1_8_8,	SNOR_CMD_READ_1_8_8 },
		{ SNOR_HWCAPS_READ_8_8_8,	SNOR_CMD_READ_8_8_8 },
		{ SNOR_HWCAPS_READ_1_8_8_DTR,	SNOR_CMD_READ_1_8_8_DTR },
	};

	return spi_nor_hwcaps2cmd(hwcaps, hwcaps_read2cmd,
				  ARRAY_SIZE(hwcaps_read2cmd));
}

static int spi_nor_hwcaps_pp2cmd(u32 hwcaps)
{
	static const int hwcaps_pp2cmd[][2] = {
		{ SNOR_HWCAPS_PP,		SNOR_CMD_PP },
		{ SNOR_HWCAPS_PP_1_1_4,		SNOR_CMD_PP_1_1_4 },
		{ SNOR_HWCAPS_PP_1_4_4,		SNOR_CMD_PP_1_4_4 },
		{ SNOR_HWCAPS_PP_4_4_4,		SNOR_CMD_PP_4_4_4 },
		{ SNOR_HWCAPS_PP_1_1_8,		SNOR_CMD_PP_1_1_8 },
		{ SNOR_HWCAPS_PP_1_8_8,		SNOR_CMD_PP_1_8_8 },
		{ SNOR_HWCAPS_PP_8_8_8,		SNOR_CMD_PP_8_8_8 },
	};

	return spi_nor_hwcaps2cmd(hwcaps, hwcaps_pp2cmd,
				  ARRAY_SIZE(hwcaps_pp2cmd));
}

/*
 * Serial Flash Discoverable Parameters (SFDP) parsing.
 */

/**
 * spi_nor_read_raw() - raw read of serial flash memory. read_opcode,
 *			addr_width and read_dummy members of the struct spi_nor
 *			should be previously
 * set.
 * @nor:	pointer to a 'struct spi_nor'
 * @addr:	offset in the serial flash memory
 * @len:	number of bytes to read
 * @buf:	buffer where the data is copied into (dma-safe memory)
 *
 * Return: 0 on success, -errno otherwise.
 */
static int spi_nor_read_raw(struct spi_nor *nor, u32 addr, size_t len, u8 *buf)
{
	ssize_t ret;

	while (len) {
		ret = spi_nor_read_data(nor, addr, len, buf);
		if (ret < 0)
			return ret;
		if (!ret || ret > len)
			return -EIO;

		buf += ret;
		addr += ret;
		len -= ret;
	}
	return 0;
}

/**
 * spi_nor_read_sfdp() - read Serial Flash Discoverable Parameters.
 * @nor:	pointer to a 'struct spi_nor'
 * @addr:	offset in the SFDP area to start reading data from
 * @len:	number of bytes to read
 * @buf:	buffer where the SFDP data are copied into (dma-safe memory)
 *
 * Whatever the actual numbers of bytes for address and dummy cycles are
 * for (Fast) Read commands, the Read SFDP (5Ah) instruction is always
 * followed by a 3-byte address and 8 dummy clock cycles.
 *
 * Return: 0 on success, -errno otherwise.
 */
static int spi_nor_read_sfdp(struct spi_nor *nor, u32 addr,
			     size_t len, void *buf)
{
	u8 addr_width, read_opcode, read_dummy;
	int ret;

	read_opcode = nor->read_opcode;
	addr_width = nor->addr_width;
	read_dummy = nor->read_dummy;

	nor->read_opcode = SPINOR_OP_RDSFDP;
	nor->addr_width = 3;
	nor->read_dummy = 8;

	ret = spi_nor_read_raw(nor, addr, len, buf);

	nor->read_opcode = read_opcode;
	nor->addr_width = addr_width;
	nor->read_dummy = read_dummy;

	return ret;
}

/**
 * spi_nor_spimem_check_op - check if the operation is supported
 *                           by controller
 *@nor:        pointer to a 'struct spi_nor'
 *@op:         pointer to op template to be checked
 *
 * Returns 0 if operation is supported, -ENOTSUPP otherwise.
 */
static int spi_nor_spimem_check_op(struct spi_nor *nor,
				   struct spi_mem_op *op)
{
	/*
	 * First test with 4 address bytes. The opcode itself might
	 * be a 3B addressing opcode but we don't care, because
	 * SPI controller implementation should not check the opcode,
	 * but just the sequence.
	 */
	op->addr.nbytes = 4;
	if (!spi_mem_supports_op(nor->spimem, op)) {
		if (nor->mtd.size > SZ_16M)
			return -ENOTSUPP;

		/* If flash size <= 16MB, 3 address bytes are sufficient */
		op->addr.nbytes = 3;
		if (!spi_mem_supports_op(nor->spimem, op))
			return -ENOTSUPP;
	}

	return 0;
}

/**
 * spi_nor_spimem_check_readop - check if the read op is supported
 *                               by controller
 *@nor:         pointer to a 'struct spi_nor'
 *@read:        pointer to op template to be checked
 *
 * Returns 0 if operation is supported, -ENOTSUPP otherwise.
 */
static int spi_nor_spimem_check_readop(struct spi_nor *nor,
				       const struct spi_nor_read_command *read)
{
	struct spi_mem_op op = SPI_MEM_OP(SPI_MEM_OP_CMD(read->opcode, 1),
					  SPI_MEM_OP_ADDR(3, 0, 1),
					  SPI_MEM_OP_DUMMY(0, 1),
					  SPI_MEM_OP_DATA_IN(0, NULL, 1));

	op.cmd.buswidth = spi_nor_get_protocol_inst_nbits(read->proto);
	op.addr.buswidth = spi_nor_get_protocol_addr_nbits(read->proto);
	op.data.buswidth = spi_nor_get_protocol_data_nbits(read->proto);
	op.dummy.buswidth = op.addr.buswidth;
	op.dummy.nbytes = (read->num_mode_clocks + read->num_wait_states) *
			  op.dummy.buswidth / 8;

	return spi_nor_spimem_check_op(nor, &op);
}

/**
 * spi_nor_spimem_check_pp - check if the page program op is supported
 *                           by controller
 *@nor:         pointer to a 'struct spi_nor'
 *@pp:          pointer to op template to be checked
 *
 * Returns 0 if operation is supported, -ENOTSUPP otherwise.
 */
static int spi_nor_spimem_check_pp(struct spi_nor *nor,
				   const struct spi_nor_pp_command *pp)
{
	struct spi_mem_op op = SPI_MEM_OP(SPI_MEM_OP_CMD(pp->opcode, 1),
					  SPI_MEM_OP_ADDR(3, 0, 1),
					  SPI_MEM_OP_NO_DUMMY,
					  SPI_MEM_OP_DATA_OUT(0, NULL, 1));

	op.cmd.buswidth = spi_nor_get_protocol_inst_nbits(pp->proto);
	op.addr.buswidth = spi_nor_get_protocol_addr_nbits(pp->proto);
	op.data.buswidth = spi_nor_get_protocol_data_nbits(pp->proto);

	return spi_nor_spimem_check_op(nor, &op);
}

/**
 * spi_nor_spimem_adjust_hwcaps - Find optimal Read/Write protocol
 *                                based on SPI controller capabilities
 * @nor:        pointer to a 'struct spi_nor'
 * @hwcaps:     pointer to resulting capabilities after adjusting
 *              according to controller and flash's capability
 */
static void
spi_nor_spimem_adjust_hwcaps(struct spi_nor *nor, u32 *hwcaps)
{
	struct spi_nor_flash_parameter *params =  &nor->params;
	unsigned int cap;

	/* DTR modes are not supported yet, mask them all. */
	*hwcaps &= ~SNOR_HWCAPS_DTR;

	/* X-X-X modes are not supported yet, mask them all. */
	*hwcaps &= ~SNOR_HWCAPS_X_X_X;

	for (cap = 0; cap < sizeof(*hwcaps) * BITS_PER_BYTE; cap++) {
		int rdidx, ppidx;

		if (!(*hwcaps & BIT(cap)))
			continue;

		rdidx = spi_nor_hwcaps_read2cmd(BIT(cap));
		if (rdidx >= 0 &&
		    spi_nor_spimem_check_readop(nor, &params->reads[rdidx]))
			*hwcaps &= ~BIT(cap);

		ppidx = spi_nor_hwcaps_pp2cmd(BIT(cap));
		if (ppidx < 0)
			continue;

		if (spi_nor_spimem_check_pp(nor,
					    &params->page_programs[ppidx]))
			*hwcaps &= ~BIT(cap);
	}
}

/**
 * spi_nor_read_sfdp_dma_unsafe() - read Serial Flash Discoverable Parameters.
 * @nor:	pointer to a 'struct spi_nor'
 * @addr:	offset in the SFDP area to start reading data from
 * @len:	number of bytes to read
 * @buf:	buffer where the SFDP data are copied into
 *
 * Wrap spi_nor_read_sfdp() using a kmalloc'ed bounce buffer as @buf is now not
 * guaranteed to be dma-safe.
 *
 * Return: -ENOMEM if kmalloc() fails, the return code of spi_nor_read_sfdp()
 *          otherwise.
 */
static int spi_nor_read_sfdp_dma_unsafe(struct spi_nor *nor, u32 addr,
					size_t len, void *buf)
{
	void *dma_safe_buf;
	int ret;

	dma_safe_buf = kmalloc(len, GFP_KERNEL);
	if (!dma_safe_buf)
		return -ENOMEM;

	ret = spi_nor_read_sfdp(nor, addr, len, dma_safe_buf);
	memcpy(buf, dma_safe_buf, len);
	kfree(dma_safe_buf);

	return ret;
}

/* Fast Read settings. */

static void
spi_nor_set_read_settings_from_bfpt(struct spi_nor_read_command *read,
				    u16 half,
				    enum spi_nor_protocol proto)
{
	read->num_mode_clocks = (half >> 5) & 0x07;
	read->num_wait_states = (half >> 0) & 0x1f;
	read->opcode = (half >> 8) & 0xff;
	read->proto = proto;
}

struct sfdp_bfpt_read {
	/* The Fast Read x-y-z hardware capability in params->hwcaps.mask. */
	u32			hwcaps;

	/*
	 * The <supported_bit> bit in <supported_dword> BFPT DWORD tells us
	 * whether the Fast Read x-y-z command is supported.
	 */
	u32			supported_dword;
	u32			supported_bit;

	/*
	 * The half-word at offset <setting_shift> in <setting_dword> BFPT DWORD
	 * encodes the op code, the number of mode clocks and the number of wait
	 * states to be used by Fast Read x-y-z command.
	 */
	u32			settings_dword;
	u32			settings_shift;

	/* The SPI protocol for this Fast Read x-y-z command. */
	enum spi_nor_protocol	proto;
};

static const struct sfdp_bfpt_read sfdp_bfpt_reads[] = {
	/* Fast Read 1-1-2 */
	{
		SNOR_HWCAPS_READ_1_1_2,
		BFPT_DWORD(1), BIT(16),	/* Supported bit */
		BFPT_DWORD(4), 0,	/* Settings */
		SNOR_PROTO_1_1_2,
	},

	/* Fast Read 1-2-2 */
	{
		SNOR_HWCAPS_READ_1_2_2,
		BFPT_DWORD(1), BIT(20),	/* Supported bit */
		BFPT_DWORD(4), 16,	/* Settings */
		SNOR_PROTO_1_2_2,
	},

	/* Fast Read 2-2-2 */
	{
		SNOR_HWCAPS_READ_2_2_2,
		BFPT_DWORD(5),  BIT(0),	/* Supported bit */
		BFPT_DWORD(6), 16,	/* Settings */
		SNOR_PROTO_2_2_2,
	},

	/* Fast Read 1-1-4 */
	{
		SNOR_HWCAPS_READ_1_1_4,
		BFPT_DWORD(1), BIT(22),	/* Supported bit */
		BFPT_DWORD(3), 16,	/* Settings */
		SNOR_PROTO_1_1_4,
	},

	/* Fast Read 1-4-4 */
	{
		SNOR_HWCAPS_READ_1_4_4,
		BFPT_DWORD(1), BIT(21),	/* Supported bit */
		BFPT_DWORD(3), 0,	/* Settings */
		SNOR_PROTO_1_4_4,
	},

	/* Fast Read 4-4-4 */
	{
		SNOR_HWCAPS_READ_4_4_4,
		BFPT_DWORD(5), BIT(4),	/* Supported bit */
		BFPT_DWORD(7), 16,	/* Settings */
		SNOR_PROTO_4_4_4,
	},
};

struct sfdp_bfpt_erase {
	/*
	 * The half-word at offset <shift> in DWORD <dwoard> encodes the
	 * op code and erase sector size to be used by Sector Erase commands.
	 */
	u32			dword;
	u32			shift;
};

static const struct sfdp_bfpt_erase sfdp_bfpt_erases[] = {
	/* Erase Type 1 in DWORD8 bits[15:0] */
	{BFPT_DWORD(8), 0},

	/* Erase Type 2 in DWORD8 bits[31:16] */
	{BFPT_DWORD(8), 16},

	/* Erase Type 3 in DWORD9 bits[15:0] */
	{BFPT_DWORD(9), 0},

	/* Erase Type 4 in DWORD9 bits[31:16] */
	{BFPT_DWORD(9), 16},
};

/**
 * spi_nor_set_erase_type() - set a SPI NOR erase type
 * @erase:	pointer to a structure that describes a SPI NOR erase type
 * @size:	the size of the sector/block erased by the erase type
 * @opcode:	the SPI command op code to erase the sector/block
 */
static void spi_nor_set_erase_type(struct spi_nor_erase_type *erase,
				   u32 size, u8 opcode)
{
	erase->size = size;
	erase->opcode = opcode;
	/* JEDEC JESD216B Standard imposes erase sizes to be power of 2. */
	erase->size_shift = ffs(erase->size) - 1;
	erase->size_mask = (1 << erase->size_shift) - 1;
}

/**
 * spi_nor_set_erase_settings_from_bfpt() - set erase type settings from BFPT
 * @erase:	pointer to a structure that describes a SPI NOR erase type
 * @size:	the size of the sector/block erased by the erase type
 * @opcode:	the SPI command op code to erase the sector/block
 * @i:		erase type index as sorted in the Basic Flash Parameter Table
 *
 * The supported Erase Types will be sorted at init in ascending order, with
 * the smallest Erase Type size being the first member in the erase_type array
 * of the spi_nor_erase_map structure. Save the Erase Type index as sorted in
 * the Basic Flash Parameter Table since it will be used later on to
 * synchronize with the supported Erase Types defined in SFDP optional tables.
 */
static void
spi_nor_set_erase_settings_from_bfpt(struct spi_nor_erase_type *erase,
				     u32 size, u8 opcode, u8 i)
{
	erase->idx = i;
	spi_nor_set_erase_type(erase, size, opcode);
}

/**
 * spi_nor_map_cmp_erase_type() - compare the map's erase types by size
 * @l:	member in the left half of the map's erase_type array
 * @r:	member in the right half of the map's erase_type array
 *
 * Comparison function used in the sort() call to sort in ascending order the
 * map's erase types, the smallest erase type size being the first member in the
 * sorted erase_type array.
 *
 * Return: the result of @l->size - @r->size
 */
static int spi_nor_map_cmp_erase_type(const void *l, const void *r)
{
	const struct spi_nor_erase_type *left = l, *right = r;

	return left->size - right->size;
}

/**
 * spi_nor_sort_erase_mask() - sort erase mask
 * @map:	the erase map of the SPI NOR
 * @erase_mask:	the erase type mask to be sorted
 *
 * Replicate the sort done for the map's erase types in BFPT: sort the erase
 * mask in ascending order with the smallest erase type size starting from
 * BIT(0) in the sorted erase mask.
 *
 * Return: sorted erase mask.
 */
static u8 spi_nor_sort_erase_mask(struct spi_nor_erase_map *map, u8 erase_mask)
{
	struct spi_nor_erase_type *erase_type = map->erase_type;
	int i;
	u8 sorted_erase_mask = 0;

	if (!erase_mask)
		return 0;

	/* Replicate the sort done for the map's erase types. */
	for (i = 0; i < SNOR_ERASE_TYPE_MAX; i++)
		if (erase_type[i].size && erase_mask & BIT(erase_type[i].idx))
			sorted_erase_mask |= BIT(i);

	return sorted_erase_mask;
}

/**
 * spi_nor_regions_sort_erase_types() - sort erase types in each region
 * @map:	the erase map of the SPI NOR
 *
 * Function assumes that the erase types defined in the erase map are already
 * sorted in ascending order, with the smallest erase type size being the first
 * member in the erase_type array. It replicates the sort done for the map's
 * erase types. Each region's erase bitmask will indicate which erase types are
 * supported from the sorted erase types defined in the erase map.
 * Sort the all region's erase type at init in order to speed up the process of
 * finding the best erase command at runtime.
 */
static void spi_nor_regions_sort_erase_types(struct spi_nor_erase_map *map)
{
	struct spi_nor_erase_region *region = map->regions;
	u8 region_erase_mask, sorted_erase_mask;

	while (region) {
		region_erase_mask = region->offset & SNOR_ERASE_TYPE_MASK;

		sorted_erase_mask = spi_nor_sort_erase_mask(map,
							    region_erase_mask);

		/* Overwrite erase mask. */
		region->offset = (region->offset & ~SNOR_ERASE_TYPE_MASK) |
				 sorted_erase_mask;

		region = spi_nor_region_next(region);
	}
}

/**
 * spi_nor_init_uniform_erase_map() - Initialize uniform erase map
 * @map:		the erase map of the SPI NOR
 * @erase_mask:		bitmask encoding erase types that can erase the entire
 *			flash memory
 * @flash_size:		the spi nor flash memory size
 */
static void spi_nor_init_uniform_erase_map(struct spi_nor_erase_map *map,
					   u8 erase_mask, u64 flash_size)
{
	/* Offset 0 with erase_mask and SNOR_LAST_REGION bit set */
	map->uniform_region.offset = (erase_mask & SNOR_ERASE_TYPE_MASK) |
				     SNOR_LAST_REGION;
	map->uniform_region.size = flash_size;
	map->regions = &map->uniform_region;
	map->uniform_erase_type = erase_mask;
}

static int
spi_nor_post_bfpt_fixups(struct spi_nor *nor,
			 const struct sfdp_parameter_header *bfpt_header,
			 const struct sfdp_bfpt *bfpt,
			 struct spi_nor_flash_parameter *params)
{
	if (nor->info->fixups && nor->info->fixups->post_bfpt)
		return nor->info->fixups->post_bfpt(nor, bfpt_header, bfpt,
						    params);

	return 0;
}

/**
 * spi_nor_parse_bfpt() - read and parse the Basic Flash Parameter Table.
 * @nor:		pointer to a 'struct spi_nor'
 * @bfpt_header:	pointer to the 'struct sfdp_parameter_header' describing
 *			the Basic Flash Parameter Table length and version
 * @params:		pointer to the 'struct spi_nor_flash_parameter' to be
 *			filled
 *
 * The Basic Flash Parameter Table is the main and only mandatory table as
 * defined by the SFDP (JESD216) specification.
 * It provides us with the total size (memory density) of the data array and
 * the number of address bytes for Fast Read, Page Program and Sector Erase
 * commands.
 * For Fast READ commands, it also gives the number of mode clock cycles and
 * wait states (regrouped in the number of dummy clock cycles) for each
 * supported instruction op code.
 * For Page Program, the page size is now available since JESD216 rev A, however
 * the supported instruction op codes are still not provided.
 * For Sector Erase commands, this table stores the supported instruction op
 * codes and the associated sector sizes.
 * Finally, the Quad Enable Requirements (QER) are also available since JESD216
 * rev A. The QER bits encode the manufacturer dependent procedure to be
 * executed to set the Quad Enable (QE) bit in some internal register of the
 * Quad SPI memory. Indeed the QE bit, when it exists, must be set before
 * sending any Quad SPI command to the memory. Actually, setting the QE bit
 * tells the memory to reassign its WP# and HOLD#/RESET# pins to functions IO2
 * and IO3 hence enabling 4 (Quad) I/O lines.
 *
 * Return: 0 on success, -errno otherwise.
 */
static int spi_nor_parse_bfpt(struct spi_nor *nor,
			      const struct sfdp_parameter_header *bfpt_header,
			      struct spi_nor_flash_parameter *params)
{
	struct spi_nor_erase_map *map = &params->erase_map;
	struct spi_nor_erase_type *erase_type = map->erase_type;
	struct sfdp_bfpt bfpt;
	size_t len;
	int i, cmd, err;
	u32 addr;
	u16 half;
	u8 erase_mask;

	/* JESD216 Basic Flash Parameter Table length is at least 9 DWORDs. */
	if (bfpt_header->length < BFPT_DWORD_MAX_JESD216)
		return -EINVAL;

	/* Read the Basic Flash Parameter Table. */
	len = min_t(size_t, sizeof(bfpt),
		    bfpt_header->length * sizeof(u32));
	addr = SFDP_PARAM_HEADER_PTP(bfpt_header);
	memset(&bfpt, 0, sizeof(bfpt));
	err = spi_nor_read_sfdp_dma_unsafe(nor,  addr, len, &bfpt);
	if (err < 0)
		return err;

	/* Fix endianness of the BFPT DWORDs. */
	for (i = 0; i < BFPT_DWORD_MAX; i++)
		bfpt.dwords[i] = le32_to_cpu(bfpt.dwords[i]);

	/* Number of address bytes. */
	switch (bfpt.dwords[BFPT_DWORD(1)] & BFPT_DWORD1_ADDRESS_BYTES_MASK) {
	case BFPT_DWORD1_ADDRESS_BYTES_3_ONLY:
		nor->addr_width = 3;
		break;

	case BFPT_DWORD1_ADDRESS_BYTES_4_ONLY:
		nor->addr_width = 4;
		break;

	default:
		break;
	}

	/* Flash Memory Density (in bits). */
	params->size = bfpt.dwords[BFPT_DWORD(2)];
	if (params->size & BIT(31)) {
		params->size &= ~BIT(31);

		/*
		 * Prevent overflows on params->size. Anyway, a NOR of 2^64
		 * bits is unlikely to exist so this error probably means
		 * the BFPT we are reading is corrupted/wrong.
		 */
		if (params->size > 63)
			return -EINVAL;

		params->size = 1ULL << params->size;
	} else {
		params->size++;
	}
	params->size >>= 3; /* Convert to bytes. */

	/* Fast Read settings. */
	for (i = 0; i < ARRAY_SIZE(sfdp_bfpt_reads); i++) {
		const struct sfdp_bfpt_read *rd = &sfdp_bfpt_reads[i];
		struct spi_nor_read_command *read;

		if (!(bfpt.dwords[rd->supported_dword] & rd->supported_bit)) {
			params->hwcaps.mask &= ~rd->hwcaps;
			continue;
		}

		params->hwcaps.mask |= rd->hwcaps;
		cmd = spi_nor_hwcaps_read2cmd(rd->hwcaps);
		read = &params->reads[cmd];
		half = bfpt.dwords[rd->settings_dword] >> rd->settings_shift;
		spi_nor_set_read_settings_from_bfpt(read, half, rd->proto);
	}

	/*
	 * Sector Erase settings. Reinitialize the uniform erase map using the
	 * Erase Types defined in the bfpt table.
	 */
	erase_mask = 0;
	memset(&params->erase_map, 0, sizeof(params->erase_map));
	for (i = 0; i < ARRAY_SIZE(sfdp_bfpt_erases); i++) {
		const struct sfdp_bfpt_erase *er = &sfdp_bfpt_erases[i];
		u32 erasesize;
		u8 opcode;

		half = bfpt.dwords[er->dword] >> er->shift;
		erasesize = half & 0xff;

		/* erasesize == 0 means this Erase Type is not supported. */
		if (!erasesize)
			continue;

		erasesize = 1U << erasesize;
		opcode = (half >> 8) & 0xff;
		erase_mask |= BIT(i);
		spi_nor_set_erase_settings_from_bfpt(&erase_type[i], erasesize,
						     opcode, i);
	}
	spi_nor_init_uniform_erase_map(map, erase_mask, params->size);
	/*
	 * Sort all the map's Erase Types in ascending order with the smallest
	 * erase size being the first member in the erase_type array.
	 */
	sort(erase_type, SNOR_ERASE_TYPE_MAX, sizeof(erase_type[0]),
	     spi_nor_map_cmp_erase_type, NULL);
	/*
	 * Sort the erase types in the uniform region in order to update the
	 * uniform_erase_type bitmask. The bitmask will be used later on when
	 * selecting the uniform erase.
	 */
	spi_nor_regions_sort_erase_types(map);
	map->uniform_erase_type = map->uniform_region.offset &
				  SNOR_ERASE_TYPE_MASK;

	/* Stop here if not JESD216 rev A or later. */
	if (bfpt_header->length < BFPT_DWORD_MAX)
		return spi_nor_post_bfpt_fixups(nor, bfpt_header, &bfpt,
						params);

	/* Page size: this field specifies 'N' so the page size = 2^N bytes. */
	params->page_size = bfpt.dwords[BFPT_DWORD(11)];
	params->page_size &= BFPT_DWORD11_PAGE_SIZE_MASK;
	params->page_size >>= BFPT_DWORD11_PAGE_SIZE_SHIFT;
	params->page_size = 1U << params->page_size;

	/* Quad Enable Requirements. */
	switch (bfpt.dwords[BFPT_DWORD(15)] & BFPT_DWORD15_QER_MASK) {
	case BFPT_DWORD15_QER_NONE:
		params->quad_enable = NULL;
		break;

	case BFPT_DWORD15_QER_SR2_BIT1_BUGGY:
		/*
		 * Writing only one byte to the Status Register has the
		 * side-effect of clearing Status Register 2.
		 */
	case BFPT_DWORD15_QER_SR2_BIT1_NO_RD:
		/*
		 * Read Configuration Register (35h) instruction is not
		 * supported.
		 */
		nor->flags |= SNOR_F_HAS_16BIT_SR | SNOR_F_NO_READ_CR;
		params->quad_enable = spansion_no_read_cr_quad_enable;
		break;

	case BFPT_DWORD15_QER_SR1_BIT6:
		nor->flags &= ~SNOR_F_HAS_16BIT_SR;
		params->quad_enable = macronix_quad_enable;
		break;

	case BFPT_DWORD15_QER_SR2_BIT7:
		nor->flags &= ~SNOR_F_HAS_16BIT_SR;
		params->quad_enable = sr2_bit7_quad_enable;
		break;

	case BFPT_DWORD15_QER_SR2_BIT1:
		/*
		 * JESD216 rev B or later does not specify if writing only one
		 * byte to the Status Register clears or not the Status
		 * Register 2, so let's be cautious and keep the default
		 * assumption of a 16-bit Write Status (01h) command.
		 */
		nor->flags |= SNOR_F_HAS_16BIT_SR;

		params->quad_enable = spansion_read_cr_quad_enable;
		break;

	default:
		return -EINVAL;
	}

	return spi_nor_post_bfpt_fixups(nor, bfpt_header, &bfpt, params);
}

#define SMPT_CMD_ADDRESS_LEN_MASK		GENMASK(23, 22)
#define SMPT_CMD_ADDRESS_LEN_0			(0x0UL << 22)
#define SMPT_CMD_ADDRESS_LEN_3			(0x1UL << 22)
#define SMPT_CMD_ADDRESS_LEN_4			(0x2UL << 22)
#define SMPT_CMD_ADDRESS_LEN_USE_CURRENT	(0x3UL << 22)

#define SMPT_CMD_READ_DUMMY_MASK		GENMASK(19, 16)
#define SMPT_CMD_READ_DUMMY_SHIFT		16
#define SMPT_CMD_READ_DUMMY(_cmd) \
	(((_cmd) & SMPT_CMD_READ_DUMMY_MASK) >> SMPT_CMD_READ_DUMMY_SHIFT)
#define SMPT_CMD_READ_DUMMY_IS_VARIABLE		0xfUL

#define SMPT_CMD_READ_DATA_MASK			GENMASK(31, 24)
#define SMPT_CMD_READ_DATA_SHIFT		24
#define SMPT_CMD_READ_DATA(_cmd) \
	(((_cmd) & SMPT_CMD_READ_DATA_MASK) >> SMPT_CMD_READ_DATA_SHIFT)

#define SMPT_CMD_OPCODE_MASK			GENMASK(15, 8)
#define SMPT_CMD_OPCODE_SHIFT			8
#define SMPT_CMD_OPCODE(_cmd) \
	(((_cmd) & SMPT_CMD_OPCODE_MASK) >> SMPT_CMD_OPCODE_SHIFT)

#define SMPT_MAP_REGION_COUNT_MASK		GENMASK(23, 16)
#define SMPT_MAP_REGION_COUNT_SHIFT		16
#define SMPT_MAP_REGION_COUNT(_header) \
	((((_header) & SMPT_MAP_REGION_COUNT_MASK) >> \
	  SMPT_MAP_REGION_COUNT_SHIFT) + 1)

#define SMPT_MAP_ID_MASK			GENMASK(15, 8)
#define SMPT_MAP_ID_SHIFT			8
#define SMPT_MAP_ID(_header) \
	(((_header) & SMPT_MAP_ID_MASK) >> SMPT_MAP_ID_SHIFT)

#define SMPT_MAP_REGION_SIZE_MASK		GENMASK(31, 8)
#define SMPT_MAP_REGION_SIZE_SHIFT		8
#define SMPT_MAP_REGION_SIZE(_region) \
	(((((_region) & SMPT_MAP_REGION_SIZE_MASK) >> \
	   SMPT_MAP_REGION_SIZE_SHIFT) + 1) * 256)

#define SMPT_MAP_REGION_ERASE_TYPE_MASK		GENMASK(3, 0)
#define SMPT_MAP_REGION_ERASE_TYPE(_region) \
	((_region) & SMPT_MAP_REGION_ERASE_TYPE_MASK)

#define SMPT_DESC_TYPE_MAP			BIT(1)
#define SMPT_DESC_END				BIT(0)

/**
 * spi_nor_smpt_addr_width() - return the address width used in the
 *			       configuration detection command.
 * @nor:	pointer to a 'struct spi_nor'
 * @settings:	configuration detection command descriptor, dword1
 */
static u8 spi_nor_smpt_addr_width(const struct spi_nor *nor, const u32 settings)
{
	switch (settings & SMPT_CMD_ADDRESS_LEN_MASK) {
	case SMPT_CMD_ADDRESS_LEN_0:
		return 0;
	case SMPT_CMD_ADDRESS_LEN_3:
		return 3;
	case SMPT_CMD_ADDRESS_LEN_4:
		return 4;
	case SMPT_CMD_ADDRESS_LEN_USE_CURRENT:
		/* fall through */
	default:
		return nor->addr_width;
	}
}

/**
 * spi_nor_smpt_read_dummy() - return the configuration detection command read
 *			       latency, in clock cycles.
 * @nor:	pointer to a 'struct spi_nor'
 * @settings:	configuration detection command descriptor, dword1
 *
 * Return: the number of dummy cycles for an SMPT read
 */
static u8 spi_nor_smpt_read_dummy(const struct spi_nor *nor, const u32 settings)
{
	u8 read_dummy = SMPT_CMD_READ_DUMMY(settings);

	if (read_dummy == SMPT_CMD_READ_DUMMY_IS_VARIABLE)
		return nor->read_dummy;
	return read_dummy;
}

/**
 * spi_nor_get_map_in_use() - get the configuration map in use
 * @nor:	pointer to a 'struct spi_nor'
 * @smpt:	pointer to the sector map parameter table
 * @smpt_len:	sector map parameter table length
 *
 * Return: pointer to the map in use, ERR_PTR(-errno) otherwise.
 */
static const u32 *spi_nor_get_map_in_use(struct spi_nor *nor, const u32 *smpt,
					 u8 smpt_len)
{
	const u32 *ret;
	u8 *buf;
	u32 addr;
	int err;
	u8 i;
	u8 addr_width, read_opcode, read_dummy;
	u8 read_data_mask, map_id;

	/* Use a kmalloc'ed bounce buffer to guarantee it is DMA-able. */
	buf = kmalloc(sizeof(*buf), GFP_KERNEL);
	if (!buf)
		return ERR_PTR(-ENOMEM);

	addr_width = nor->addr_width;
	read_dummy = nor->read_dummy;
	read_opcode = nor->read_opcode;

	map_id = 0;
	/* Determine if there are any optional Detection Command Descriptors */
	for (i = 0; i < smpt_len; i += 2) {
		if (smpt[i] & SMPT_DESC_TYPE_MAP)
			break;

		read_data_mask = SMPT_CMD_READ_DATA(smpt[i]);
		nor->addr_width = spi_nor_smpt_addr_width(nor, smpt[i]);
		nor->read_dummy = spi_nor_smpt_read_dummy(nor, smpt[i]);
		nor->read_opcode = SMPT_CMD_OPCODE(smpt[i]);
		addr = smpt[i + 1];

		err = spi_nor_read_raw(nor, addr, 1, buf);
		if (err) {
			ret = ERR_PTR(err);
			goto out;
		}

		/*
		 * Build an index value that is used to select the Sector Map
		 * Configuration that is currently in use.
		 */
		map_id = map_id << 1 | !!(*buf & read_data_mask);
	}

	/*
	 * If command descriptors are provided, they always precede map
	 * descriptors in the table. There is no need to start the iteration
	 * over smpt array all over again.
	 *
	 * Find the matching configuration map.
	 */
	ret = ERR_PTR(-EINVAL);
	while (i < smpt_len) {
		if (SMPT_MAP_ID(smpt[i]) == map_id) {
			ret = smpt + i;
			break;
		}

		/*
		 * If there are no more configuration map descriptors and no
		 * configuration ID matched the configuration identifier, the
		 * sector address map is unknown.
		 */
		if (smpt[i] & SMPT_DESC_END)
			break;

		/* increment the table index to the next map */
		i += SMPT_MAP_REGION_COUNT(smpt[i]) + 1;
	}

	/* fall through */
out:
	kfree(buf);
	nor->addr_width = addr_width;
	nor->read_dummy = read_dummy;
	nor->read_opcode = read_opcode;
	return ret;
}

/**
 * spi_nor_region_check_overlay() - set overlay bit when the region is overlaid
 * @region:	pointer to a structure that describes a SPI NOR erase region
 * @erase:	pointer to a structure that describes a SPI NOR erase type
 * @erase_type:	erase type bitmask
 */
static void
spi_nor_region_check_overlay(struct spi_nor_erase_region *region,
			     const struct spi_nor_erase_type *erase,
			     const u8 erase_type)
{
	int i;

	for (i = 0; i < SNOR_ERASE_TYPE_MAX; i++) {
		if (!(erase_type & BIT(i)))
			continue;
		if (region->size & erase[i].size_mask) {
			spi_nor_region_mark_overlay(region);
			return;
		}
	}
}

/**
 * spi_nor_init_non_uniform_erase_map() - initialize the non-uniform erase map
 * @nor:	pointer to a 'struct spi_nor'
 * @params:     pointer to a duplicate 'struct spi_nor_flash_parameter' that is
 *              used for storing SFDP parsed data
 * @smpt:	pointer to the sector map parameter table
 *
 * Return: 0 on success, -errno otherwise.
 */
static int
spi_nor_init_non_uniform_erase_map(struct spi_nor *nor,
				   struct spi_nor_flash_parameter *params,
				   const u32 *smpt)
{
	struct spi_nor_erase_map *map = &params->erase_map;
	struct spi_nor_erase_type *erase = map->erase_type;
	struct spi_nor_erase_region *region;
	u64 offset;
	u32 region_count;
	int i, j;
	u8 uniform_erase_type, save_uniform_erase_type;
	u8 erase_type, regions_erase_type;

	region_count = SMPT_MAP_REGION_COUNT(*smpt);
	/*
	 * The regions will be freed when the driver detaches from the
	 * device.
	 */
	region = devm_kcalloc(nor->dev, region_count, sizeof(*region),
			      GFP_KERNEL);
	if (!region)
		return -ENOMEM;
	map->regions = region;

	uniform_erase_type = 0xff;
	regions_erase_type = 0;
	offset = 0;
	/* Populate regions. */
	for (i = 0; i < region_count; i++) {
		j = i + 1; /* index for the region dword */
		region[i].size = SMPT_MAP_REGION_SIZE(smpt[j]);
		erase_type = SMPT_MAP_REGION_ERASE_TYPE(smpt[j]);
		region[i].offset = offset | erase_type;

		spi_nor_region_check_overlay(&region[i], erase, erase_type);

		/*
		 * Save the erase types that are supported in all regions and
		 * can erase the entire flash memory.
		 */
		uniform_erase_type &= erase_type;

		/*
		 * regions_erase_type mask will indicate all the erase types
		 * supported in this configuration map.
		 */
		regions_erase_type |= erase_type;

		offset = (region[i].offset & ~SNOR_ERASE_FLAGS_MASK) +
			 region[i].size;
	}

	save_uniform_erase_type = map->uniform_erase_type;
	map->uniform_erase_type = spi_nor_sort_erase_mask(map,
							  uniform_erase_type);

	if (!regions_erase_type) {
		/*
		 * Roll back to the previous uniform_erase_type mask, SMPT is
		 * broken.
		 */
		map->uniform_erase_type = save_uniform_erase_type;
		return -EINVAL;
	}

	/*
	 * BFPT advertises all the erase types supported by all the possible
	 * map configurations. Mask out the erase types that are not supported
	 * by the current map configuration.
	 */
	for (i = 0; i < SNOR_ERASE_TYPE_MAX; i++)
		if (!(regions_erase_type & BIT(erase[i].idx)))
			spi_nor_set_erase_type(&erase[i], 0, 0xFF);

	spi_nor_region_mark_end(&region[i - 1]);

	return 0;
}

/**
 * spi_nor_parse_smpt() - parse Sector Map Parameter Table
 * @nor:		pointer to a 'struct spi_nor'
 * @smpt_header:	sector map parameter table header
 * @params:		pointer to a duplicate 'struct spi_nor_flash_parameter'
 *                      that is used for storing SFDP parsed data
 *
 * This table is optional, but when available, we parse it to identify the
 * location and size of sectors within the main data array of the flash memory
 * device and to identify which Erase Types are supported by each sector.
 *
 * Return: 0 on success, -errno otherwise.
 */
static int spi_nor_parse_smpt(struct spi_nor *nor,
			      const struct sfdp_parameter_header *smpt_header,
			      struct spi_nor_flash_parameter *params)
{
	const u32 *sector_map;
	u32 *smpt;
	size_t len;
	u32 addr;
	int i, ret;

	/* Read the Sector Map Parameter Table. */
	len = smpt_header->length * sizeof(*smpt);
	smpt = kmalloc(len, GFP_KERNEL);
	if (!smpt)
		return -ENOMEM;

	addr = SFDP_PARAM_HEADER_PTP(smpt_header);
	ret = spi_nor_read_sfdp(nor, addr, len, smpt);
	if (ret)
		goto out;

	/* Fix endianness of the SMPT DWORDs. */
	for (i = 0; i < smpt_header->length; i++)
		smpt[i] = le32_to_cpu(smpt[i]);

	sector_map = spi_nor_get_map_in_use(nor, smpt, smpt_header->length);
	if (IS_ERR(sector_map)) {
		ret = PTR_ERR(sector_map);
		goto out;
	}

	ret = spi_nor_init_non_uniform_erase_map(nor, params, sector_map);
	if (ret)
		goto out;

	spi_nor_regions_sort_erase_types(&params->erase_map);
	/* fall through */
out:
	kfree(smpt);
	return ret;
}

#define SFDP_4BAIT_DWORD_MAX	2

struct sfdp_4bait {
	/* The hardware capability. */
	u32		hwcaps;

	/*
	 * The <supported_bit> bit in DWORD1 of the 4BAIT tells us whether
	 * the associated 4-byte address op code is supported.
	 */
	u32		supported_bit;
};

/**
 * spi_nor_parse_4bait() - parse the 4-Byte Address Instruction Table
 * @nor:		pointer to a 'struct spi_nor'.
 * @param_header:	pointer to the 'struct sfdp_parameter_header' describing
 *			the 4-Byte Address Instruction Table length and version.
 * @params:		pointer to the 'struct spi_nor_flash_parameter' to be.
 *
 * Return: 0 on success, -errno otherwise.
 */
static int spi_nor_parse_4bait(struct spi_nor *nor,
			       const struct sfdp_parameter_header *param_header,
			       struct spi_nor_flash_parameter *params)
{
	static const struct sfdp_4bait reads[] = {
		{ SNOR_HWCAPS_READ,		BIT(0) },
		{ SNOR_HWCAPS_READ_FAST,	BIT(1) },
		{ SNOR_HWCAPS_READ_1_1_2,	BIT(2) },
		{ SNOR_HWCAPS_READ_1_2_2,	BIT(3) },
		{ SNOR_HWCAPS_READ_1_1_4,	BIT(4) },
		{ SNOR_HWCAPS_READ_1_4_4,	BIT(5) },
		{ SNOR_HWCAPS_READ_1_1_1_DTR,	BIT(13) },
		{ SNOR_HWCAPS_READ_1_2_2_DTR,	BIT(14) },
		{ SNOR_HWCAPS_READ_1_4_4_DTR,	BIT(15) },
	};
	static const struct sfdp_4bait programs[] = {
		{ SNOR_HWCAPS_PP,		BIT(6) },
		{ SNOR_HWCAPS_PP_1_1_4,		BIT(7) },
		{ SNOR_HWCAPS_PP_1_4_4,		BIT(8) },
	};
	static const struct sfdp_4bait erases[SNOR_ERASE_TYPE_MAX] = {
		{ 0u /* not used */,		BIT(9) },
		{ 0u /* not used */,		BIT(10) },
		{ 0u /* not used */,		BIT(11) },
		{ 0u /* not used */,		BIT(12) },
	};
	struct spi_nor_pp_command *params_pp = params->page_programs;
	struct spi_nor_erase_map *map = &params->erase_map;
	struct spi_nor_erase_type *erase_type = map->erase_type;
	u32 *dwords;
	size_t len;
	u32 addr, discard_hwcaps, read_hwcaps, pp_hwcaps, erase_mask;
	int i, ret;

	if (param_header->major != SFDP_JESD216_MAJOR ||
	    param_header->length < SFDP_4BAIT_DWORD_MAX)
		return -EINVAL;

	/* Read the 4-byte Address Instruction Table. */
	len = sizeof(*dwords) * SFDP_4BAIT_DWORD_MAX;

	/* Use a kmalloc'ed bounce buffer to guarantee it is DMA-able. */
	dwords = kmalloc(len, GFP_KERNEL);
	if (!dwords)
		return -ENOMEM;

	addr = SFDP_PARAM_HEADER_PTP(param_header);
	ret = spi_nor_read_sfdp(nor, addr, len, dwords);
	if (ret)
		goto out;

	/* Fix endianness of the 4BAIT DWORDs. */
	for (i = 0; i < SFDP_4BAIT_DWORD_MAX; i++)
		dwords[i] = le32_to_cpu(dwords[i]);

	/*
	 * Compute the subset of (Fast) Read commands for which the 4-byte
	 * version is supported.
	 */
	discard_hwcaps = 0;
	read_hwcaps = 0;
	for (i = 0; i < ARRAY_SIZE(reads); i++) {
		const struct sfdp_4bait *read = &reads[i];

		discard_hwcaps |= read->hwcaps;
		if ((params->hwcaps.mask & read->hwcaps) &&
		    (dwords[0] & read->supported_bit))
			read_hwcaps |= read->hwcaps;
	}

	/*
	 * Compute the subset of Page Program commands for which the 4-byte
	 * version is supported.
	 */
	pp_hwcaps = 0;
	for (i = 0; i < ARRAY_SIZE(programs); i++) {
		const struct sfdp_4bait *program = &programs[i];

		/*
		 * The 4 Byte Address Instruction (Optional) Table is the only
		 * SFDP table that indicates support for Page Program Commands.
		 * Bypass the params->hwcaps.mask and consider 4BAIT the biggest
		 * authority for specifying Page Program support.
		 */
		discard_hwcaps |= program->hwcaps;
		if (dwords[0] & program->supported_bit)
			pp_hwcaps |= program->hwcaps;
	}

	/*
	 * Compute the subset of Sector Erase commands for which the 4-byte
	 * version is supported.
	 */
	erase_mask = 0;
	for (i = 0; i < SNOR_ERASE_TYPE_MAX; i++) {
		const struct sfdp_4bait *erase = &erases[i];

		if (dwords[0] & erase->supported_bit)
			erase_mask |= BIT(i);
	}

	/* Replicate the sort done for the map's erase types in BFPT. */
	erase_mask = spi_nor_sort_erase_mask(map, erase_mask);

	/*
	 * We need at least one 4-byte op code per read, program and erase
	 * operation; the .read(), .write() and .erase() hooks share the
	 * nor->addr_width value.
	 */
	if (!read_hwcaps || !pp_hwcaps || !erase_mask)
		goto out;

	/*
	 * Discard all operations from the 4-byte instruction set which are
	 * not supported by this memory.
	 */
	params->hwcaps.mask &= ~discard_hwcaps;
	params->hwcaps.mask |= (read_hwcaps | pp_hwcaps);

	/* Use the 4-byte address instruction set. */
	for (i = 0; i < SNOR_CMD_READ_MAX; i++) {
		struct spi_nor_read_command *read_cmd = &params->reads[i];

		read_cmd->opcode = spi_nor_convert_3to4_read(read_cmd->opcode);
	}

	/* 4BAIT is the only SFDP table that indicates page program support. */
	if (pp_hwcaps & SNOR_HWCAPS_PP)
		spi_nor_set_pp_settings(&params_pp[SNOR_CMD_PP],
					SPINOR_OP_PP_4B, SNOR_PROTO_1_1_1);
	if (pp_hwcaps & SNOR_HWCAPS_PP_1_1_4)
		spi_nor_set_pp_settings(&params_pp[SNOR_CMD_PP_1_1_4],
					SPINOR_OP_PP_1_1_4_4B,
					SNOR_PROTO_1_1_4);
	if (pp_hwcaps & SNOR_HWCAPS_PP_1_4_4)
		spi_nor_set_pp_settings(&params_pp[SNOR_CMD_PP_1_4_4],
					SPINOR_OP_PP_1_4_4_4B,
					SNOR_PROTO_1_4_4);

	for (i = 0; i < SNOR_ERASE_TYPE_MAX; i++) {
		if (erase_mask & BIT(i))
			erase_type[i].opcode = (dwords[1] >>
						erase_type[i].idx * 8) & 0xFF;
		else
			spi_nor_set_erase_type(&erase_type[i], 0u, 0xFF);
	}

	/*
	 * We set SNOR_F_HAS_4BAIT in order to skip spi_nor_set_4byte_opcodes()
	 * later because we already did the conversion to 4byte opcodes. Also,
	 * this latest function implements a legacy quirk for the erase size of
	 * Spansion memory. However this quirk is no longer needed with new
	 * SFDP compliant memories.
	 */
	nor->addr_width = 4;
	nor->flags |= SNOR_F_4B_OPCODES | SNOR_F_HAS_4BAIT;

	/* fall through */
out:
	kfree(dwords);
	return ret;
}

/**
 * spi_nor_parse_sfdp() - parse the Serial Flash Discoverable Parameters.
 * @nor:		pointer to a 'struct spi_nor'
 * @params:		pointer to the 'struct spi_nor_flash_parameter' to be
 *			filled
 *
 * The Serial Flash Discoverable Parameters are described by the JEDEC JESD216
 * specification. This is a standard which tends to supported by almost all
 * (Q)SPI memory manufacturers. Those hard-coded tables allow us to learn at
 * runtime the main parameters needed to perform basic SPI flash operations such
 * as Fast Read, Page Program or Sector Erase commands.
 *
 * Return: 0 on success, -errno otherwise.
 */
static int spi_nor_parse_sfdp(struct spi_nor *nor,
			      struct spi_nor_flash_parameter *params)
{
	const struct sfdp_parameter_header *param_header, *bfpt_header;
	struct sfdp_parameter_header *param_headers = NULL;
	struct sfdp_header header;
	struct device *dev = nor->dev;
	size_t psize;
	int i, err;

	/* Get the SFDP header. */
	err = spi_nor_read_sfdp_dma_unsafe(nor, 0, sizeof(header), &header);
	if (err < 0)
		return err;

	/* Check the SFDP header version. */
	if (le32_to_cpu(header.signature) != SFDP_SIGNATURE ||
	    header.major != SFDP_JESD216_MAJOR)
		return -EINVAL;

	/*
	 * Verify that the first and only mandatory parameter header is a
	 * Basic Flash Parameter Table header as specified in JESD216.
	 */
	bfpt_header = &header.bfpt_header;
	if (SFDP_PARAM_HEADER_ID(bfpt_header) != SFDP_BFPT_ID ||
	    bfpt_header->major != SFDP_JESD216_MAJOR)
		return -EINVAL;

	/*
	 * Allocate memory then read all parameter headers with a single
	 * Read SFDP command. These parameter headers will actually be parsed
	 * twice: a first time to get the latest revision of the basic flash
	 * parameter table, then a second time to handle the supported optional
	 * tables.
	 * Hence we read the parameter headers once for all to reduce the
	 * processing time. Also we use kmalloc() instead of devm_kmalloc()
	 * because we don't need to keep these parameter headers: the allocated
	 * memory is always released with kfree() before exiting this function.
	 */
	if (header.nph) {
		psize = header.nph * sizeof(*param_headers);

		param_headers = kmalloc(psize, GFP_KERNEL);
		if (!param_headers)
			return -ENOMEM;

		err = spi_nor_read_sfdp(nor, sizeof(header),
					psize, param_headers);
		if (err < 0) {
			dev_dbg(dev, "failed to read SFDP parameter headers\n");
			goto exit;
		}
	}

	/*
	 * Check other parameter headers to get the latest revision of
	 * the basic flash parameter table.
	 */
	for (i = 0; i < header.nph; i++) {
		param_header = &param_headers[i];

		if (SFDP_PARAM_HEADER_ID(param_header) == SFDP_BFPT_ID &&
		    param_header->major == SFDP_JESD216_MAJOR &&
		    (param_header->minor > bfpt_header->minor ||
		     (param_header->minor == bfpt_header->minor &&
		      param_header->length > bfpt_header->length)))
			bfpt_header = param_header;
	}

	err = spi_nor_parse_bfpt(nor, bfpt_header, params);
	if (err)
		goto exit;

	/* Parse optional parameter tables. */
	for (i = 0; i < header.nph; i++) {
		param_header = &param_headers[i];

		switch (SFDP_PARAM_HEADER_ID(param_header)) {
		case SFDP_SECTOR_MAP_ID:
			err = spi_nor_parse_smpt(nor, param_header, params);
			break;

		case SFDP_4BAIT_ID:
			err = spi_nor_parse_4bait(nor, param_header, params);
			break;

		default:
			break;
		}

		if (err) {
			dev_warn(dev, "Failed to parse optional parameter table: %04x\n",
				 SFDP_PARAM_HEADER_ID(param_header));
			/*
			 * Let's not drop all information we extracted so far
			 * if optional table parsers fail. In case of failing,
			 * each optional parser is responsible to roll back to
			 * the previously known spi_nor data.
			 */
			err = 0;
		}
	}

exit:
	kfree(param_headers);
	return err;
}

static int spi_nor_select_read(struct spi_nor *nor,
			       u32 shared_hwcaps)
{
	int cmd, best_match = fls(shared_hwcaps & SNOR_HWCAPS_READ_MASK) - 1;
	const struct spi_nor_read_command *read;

	if (best_match < 0)
		return -EINVAL;

	cmd = spi_nor_hwcaps_read2cmd(BIT(best_match));
	if (cmd < 0)
		return -EINVAL;

	read = &nor->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_select_pp(struct spi_nor *nor,
			     u32 shared_hwcaps)
{
	int cmd, best_match = fls(shared_hwcaps & SNOR_HWCAPS_PP_MASK) - 1;
	const struct spi_nor_pp_command *pp;

	if (best_match < 0)
		return -EINVAL;

	cmd = spi_nor_hwcaps_pp2cmd(BIT(best_match));
	if (cmd < 0)
		return -EINVAL;

	pp = &nor->params.page_programs[cmd];
	nor->program_opcode = pp->opcode;
	nor->write_proto = pp->proto;
	return 0;
}

/**
 * spi_nor_select_uniform_erase() - select optimum uniform erase type
 * @map:		the erase map of the SPI NOR
 * @wanted_size:	the erase type size to search for. Contains the value of
 *			info->sector_size or of the "small sector" size in case
 *			CONFIG_MTD_SPI_NOR_USE_4K_SECTORS is defined.
 *
 * Once the optimum uniform sector erase command is found, disable all the
 * other.
 *
 * Return: pointer to erase type on success, NULL otherwise.
 */
static const struct spi_nor_erase_type *
spi_nor_select_uniform_erase(struct spi_nor_erase_map *map,
			     const u32 wanted_size)
{
	const struct spi_nor_erase_type *tested_erase, *erase = NULL;
	int i;
	u8 uniform_erase_type = map->uniform_erase_type;

	for (i = SNOR_ERASE_TYPE_MAX - 1; i >= 0; i--) {
		if (!(uniform_erase_type & BIT(i)))
			continue;

		tested_erase = &map->erase_type[i];

		/*
		 * If the current erase size is the one, stop here:
		 * we have found the right uniform Sector Erase command.
		 */
		if (tested_erase->size == wanted_size) {
			erase = tested_erase;
			break;
		}

		/*
		 * Otherwise, the current erase size is still a valid canditate.
		 * Select the biggest valid candidate.
		 */
		if (!erase && tested_erase->size)
			erase = tested_erase;
			/* keep iterating to find the wanted_size */
	}

	if (!erase)
		return NULL;

	/* Disable all other Sector Erase commands. */
	map->uniform_erase_type &= ~SNOR_ERASE_TYPE_MASK;
	map->uniform_erase_type |= BIT(erase - map->erase_type);
	return erase;
}

static int spi_nor_select_erase(struct spi_nor *nor)
{
	struct spi_nor_erase_map *map = &nor->params.erase_map;
	const struct spi_nor_erase_type *erase = NULL;
	struct mtd_info *mtd = &nor->mtd;
	u32 wanted_size = nor->info->sector_size;
	int i;

	/*
	 * The previous implementation handling Sector Erase commands assumed
	 * that the SPI flash memory has an uniform layout then used only one
	 * of the supported erase sizes for all Sector Erase commands.
	 * So to be backward compatible, the new implementation also tries to
	 * manage the SPI flash memory as uniform with a single erase sector
	 * size, when possible.
	 */
#ifdef CONFIG_MTD_SPI_NOR_USE_4K_SECTORS
	/* prefer "small sector" erase if possible */
	wanted_size = 4096u;
#endif

	if (spi_nor_has_uniform_erase(nor)) {
		erase = spi_nor_select_uniform_erase(map, wanted_size);
		if (!erase)
			return -EINVAL;
		nor->erase_opcode = erase->opcode;
		mtd->erasesize = erase->size;
		return 0;
	}

	/*
	 * For non-uniform SPI flash memory, set mtd->erasesize to the
	 * maximum erase sector size. No need to set nor->erase_opcode.
	 */
	for (i = SNOR_ERASE_TYPE_MAX - 1; i >= 0; i--) {
		if (map->erase_type[i].size) {
			erase = &map->erase_type[i];
			break;
		}
	}

	if (!erase)
		return -EINVAL;

	mtd->erasesize = erase->size;
	return 0;
}

static int spi_nor_default_setup(struct spi_nor *nor,
				 const struct spi_nor_hwcaps *hwcaps)
{
	struct spi_nor_flash_parameter *params = &nor->params;
	u32 ignored_mask, 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;

	if (nor->spimem) {
		/*
		 * When called from spi_nor_probe(), all caps are set and we
		 * need to discard some of them based on what the SPI
		 * controller actually supports (using spi_mem_supports_op()).
		 */
		spi_nor_spimem_adjust_hwcaps(nor, &shared_mask);
	} else {
		/*
		 * SPI n-n-n protocols are not supported when the SPI
		 * controller directly implements the spi_nor interface.
		 * Yet another reason to switch to spi-mem.
		 */
		ignored_mask = SNOR_HWCAPS_X_X_X;
		if (shared_mask & ignored_mask) {
			dev_dbg(nor->dev,
				"SPI n-n-n protocols are not supported.\n");
			shared_mask &= ~ignored_mask;
		}
	}

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

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

	/* Select the Sector Erase command. */
	err = spi_nor_select_erase(nor);
	if (err) {
		dev_dbg(nor->dev,
			"can't select erase settings supported by both the SPI controller and memory.\n");
		return err;
	}

	return 0;
}

static int spi_nor_setup(struct spi_nor *nor,
			 const struct spi_nor_hwcaps *hwcaps)
{
	if (!nor->params.setup)
		return 0;

	return nor->params.setup(nor, hwcaps);
}

static void atmel_set_default_init(struct spi_nor *nor)
{
	nor->flags |= SNOR_F_HAS_LOCK;
}

static void intel_set_default_init(struct spi_nor *nor)
{
	nor->flags |= SNOR_F_HAS_LOCK;
}

static void macronix_set_default_init(struct spi_nor *nor)
{
	nor->params.quad_enable = macronix_quad_enable;
	nor->params.set_4byte = macronix_set_4byte;
}

static void sst_set_default_init(struct spi_nor *nor)
{
	nor->flags |= SNOR_F_HAS_LOCK;
}

static void st_micron_set_default_init(struct spi_nor *nor)
{
	nor->flags |= SNOR_F_HAS_LOCK;
	nor->params.quad_enable = NULL;
	nor->params.set_4byte = st_micron_set_4byte;
}

static void winbond_set_default_init(struct spi_nor *nor)
{
	nor->params.set_4byte = winbond_set_4byte;
}

/**
 * spi_nor_manufacturer_init_params() - Initialize the flash's parameters and
 * settings based on MFR register and ->default_init() hook.
 * @nor:	pointer to a 'struct spi-nor'.
 */
static void spi_nor_manufacturer_init_params(struct spi_nor *nor)
{
	/* Init flash parameters based on MFR */
	switch (JEDEC_MFR(nor->info)) {
	case SNOR_MFR_ATMEL:
		atmel_set_default_init(nor);
		break;

	case SNOR_MFR_INTEL:
		intel_set_default_init(nor);
		break;

	case SNOR_MFR_MACRONIX:
		macronix_set_default_init(nor);
		break;

	case SNOR_MFR_ST:
	case SNOR_MFR_MICRON:
		st_micron_set_default_init(nor);
		break;

	case SNOR_MFR_SST:
		sst_set_default_init(nor);
		break;

	case SNOR_MFR_WINBOND:
		winbond_set_default_init(nor);
		break;

	default:
		break;
	}

	if (nor->info->fixups && nor->info->fixups->default_init)
		nor->info->fixups->default_init(nor);
}

/**
 * spi_nor_sfdp_init_params() - Initialize the flash's parameters and settings
 * based on JESD216 SFDP standard.
 * @nor:	pointer to a 'struct spi-nor'.
 *
 * The method has a roll-back mechanism: in case the SFDP parsing fails, the
 * legacy flash parameters and settings will be restored.
 */
static void spi_nor_sfdp_init_params(struct spi_nor *nor)
{
	struct spi_nor_flash_parameter sfdp_params;

	memcpy(&sfdp_params, &nor->params, sizeof(sfdp_params));

	if (spi_nor_parse_sfdp(nor, &sfdp_params)) {
		nor->addr_width = 0;
		nor->flags &= ~SNOR_F_4B_OPCODES;
	} else {
		memcpy(&nor->params, &sfdp_params, sizeof(nor->params));
	}
}

/**
 * spi_nor_info_init_params() - Initialize the flash's parameters and settings
 * based on nor->info data.
 * @nor:	pointer to a 'struct spi-nor'.
 */
static void spi_nor_info_init_params(struct spi_nor *nor)
{
	struct spi_nor_flash_parameter *params = &nor->params;
	struct spi_nor_erase_map *map = &params->erase_map;
	const struct flash_info *info = nor->info;
	struct device_node *np = spi_nor_get_flash_node(nor);
	u8 i, erase_mask;

	/* Initialize legacy flash parameters and settings. */
	params->quad_enable = spansion_read_cr_quad_enable;
	params->set_4byte = spansion_set_4byte;
	params->setup = spi_nor_default_setup;
	/* Default to 16-bit Write Status (01h) Command */
	nor->flags |= SNOR_F_HAS_16BIT_SR;

	/* Set SPI NOR sizes. */
	params->size = (u64)info->sector_size * info->n_sectors;
	params->page_size = info->page_size;

	if (!(info->flags & SPI_NOR_NO_FR)) {
		/* Default to Fast Read for DT and non-DT platform devices. */
		params->hwcaps.mask |= SNOR_HWCAPS_READ_FAST;

		/* Mask out Fast Read if not requested at DT instantiation. */
		if (np && !of_property_read_bool(np, "m25p,fast-read"))
			params->hwcaps.mask &= ~SNOR_HWCAPS_READ_FAST;
	}

	/* (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 (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_DUAL_READ) {
		params->hwcaps.mask |= SNOR_HWCAPS_READ_1_1_2;
		spi_nor_set_read_settings(&params->reads[SNOR_CMD_READ_1_1_2],
					  0, 8, SPINOR_OP_READ_1_1_2,
					  SNOR_PROTO_1_1_2);
	}

	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);
	}

	if (info->flags & SPI_NOR_OCTAL_READ) {
		params->hwcaps.mask |= SNOR_HWCAPS_READ_1_1_8;
		spi_nor_set_read_settings(&params->reads[SNOR_CMD_READ_1_1_8],
					  0, 8, SPINOR_OP_READ_1_1_8,
					  SNOR_PROTO_1_1_8);
	}

	/* Page Program settings. */
	params->hwcaps.mask |= SNOR_HWCAPS_PP;
	spi_nor_set_pp_settings(&params->page_programs[SNOR_CMD_PP],
				SPINOR_OP_PP, SNOR_PROTO_1_1_1);

	/*
	 * Sector Erase settings. Sort Erase Types in ascending order, with the
	 * smallest erase size starting at BIT(0).
	 */
	erase_mask = 0;
	i = 0;
	if (info->flags & SECT_4K_PMC) {
		erase_mask |= BIT(i);
		spi_nor_set_erase_type(&map->erase_type[i], 4096u,
				       SPINOR_OP_BE_4K_PMC);
		i++;
	} else if (info->flags & SECT_4K) {
		erase_mask |= BIT(i);
		spi_nor_set_erase_type(&map->erase_type[i], 4096u,
				       SPINOR_OP_BE_4K);
		i++;
	}
	erase_mask |= BIT(i);
	spi_nor_set_erase_type(&map->erase_type[i], info->sector_size,
			       SPINOR_OP_SE);
	spi_nor_init_uniform_erase_map(map, erase_mask, params->size);
}

static void spansion_post_sfdp_fixups(struct spi_nor *nor)
{
	struct mtd_info *mtd = &nor->mtd;

	if (mtd->size <= SZ_16M)
		return;

	nor->flags |= SNOR_F_4B_OPCODES;
	/* No small sector erase for 4-byte command set */
	nor->erase_opcode = SPINOR_OP_SE;
	nor->mtd.erasesize = nor->info->sector_size;
}

static void s3an_post_sfdp_fixups(struct spi_nor *nor)
{
	nor->params.setup = s3an_nor_setup;
}

/**
 * spi_nor_post_sfdp_fixups() - Updates the flash's parameters and settings
 * after SFDP has been parsed (is also called for SPI NORs that do not
 * support RDSFDP).
 * @nor:	pointer to a 'struct spi_nor'
 *
 * Typically used to tweak various parameters that could not be extracted by
 * other means (i.e. when information provided by the SFDP/flash_info tables
 * are incomplete or wrong).
 */
static void spi_nor_post_sfdp_fixups(struct spi_nor *nor)
{
	switch (JEDEC_MFR(nor->info)) {
	case SNOR_MFR_SPANSION:
		spansion_post_sfdp_fixups(nor);
		break;

	default:
		break;
	}

	if (nor->info->flags & SPI_S3AN)
		s3an_post_sfdp_fixups(nor);

	if (nor->info->fixups && nor->info->fixups->post_sfdp)
		nor->info->fixups->post_sfdp(nor);
}

/**
 * spi_nor_late_init_params() - Late initialization of default flash parameters.
 * @nor:	pointer to a 'struct spi_nor'
 *
 * Used to set default flash parameters and settings when the ->default_init()
 * hook or the SFDP parser let voids.
 */
static void spi_nor_late_init_params(struct spi_nor *nor)
{
	/*
	 * NOR protection support. When locking_ops are not provided, we pick
	 * the default ones.
	 */
	if (nor->flags & SNOR_F_HAS_LOCK && !nor->params.locking_ops)
		nor->params.locking_ops = &stm_locking_ops;
}

/**
 * spi_nor_init_params() - Initialize the flash's parameters and settings.
 * @nor:	pointer to a 'struct spi-nor'.
 *
 * The flash parameters and settings are initialized based on a sequence of
 * calls that are ordered by priority:
 *
 * 1/ Default flash parameters initialization. The initializations are done
 *    based on nor->info data:
 *		spi_nor_info_init_params()
 *
 * which can be overwritten by:
 * 2/ Manufacturer flash parameters initialization. The initializations are
 *    done based on MFR register, or when the decisions can not be done solely
 *    based on MFR, by using specific flash_info tweeks, ->default_init():
 *		spi_nor_manufacturer_init_params()
 *
 * which can be overwritten by:
 * 3/ SFDP flash parameters initialization. JESD216 SFDP is a standard and
 *    should be more accurate that the above.
 *		spi_nor_sfdp_init_params()
 *
 *    Please note that there is a ->post_bfpt() fixup hook that can overwrite
 *    the flash parameters and settings immediately after parsing the Basic
 *    Flash Parameter Table.
 *
 * which can be overwritten by:
 * 4/ Post SFDP flash parameters initialization. Used to tweak various
 *    parameters that could not be extracted by other means (i.e. when
 *    information provided by the SFDP/flash_info tables are incomplete or
 *    wrong).
 *		spi_nor_post_sfdp_fixups()
 *
 * 5/ Late default flash parameters initialization, used when the
 * ->default_init() hook or the SFDP parser do not set specific params.
 *		spi_nor_late_init_params()
 */
static void spi_nor_init_params(struct spi_nor *nor)
{
	spi_nor_info_init_params(nor);

	spi_nor_manufacturer_init_params(nor);

	if ((nor->info->flags & (SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ)) &&
	    !(nor->info->flags & SPI_NOR_SKIP_SFDP))
		spi_nor_sfdp_init_params(nor);

	spi_nor_post_sfdp_fixups(nor);

	spi_nor_late_init_params(nor);
}

/**
 * spi_nor_quad_enable() - enable Quad I/O if needed.
 * @nor:                pointer to a 'struct spi_nor'
 *
 * Return: 0 on success, -errno otherwise.
 */
static int spi_nor_quad_enable(struct spi_nor *nor)
{
	if (!nor->params.quad_enable)
		return 0;

	if (!(spi_nor_get_protocol_width(nor->read_proto) == 4 ||
	      spi_nor_get_protocol_width(nor->write_proto) == 4))
		return 0;

	return nor->params.quad_enable(nor);
}

/**
 * spi_nor_unlock_all() - Unlocks the entire flash memory array.
 * @nor:	pointer to a 'struct spi_nor'.
 *
 * Some SPI NOR flashes are write protected by default after a power-on reset
 * cycle, in order to avoid inadvertent writes during power-up. Backward
 * compatibility imposes to unlock the entire flash memory array at power-up
 * by default.
 */
static int spi_nor_unlock_all(struct spi_nor *nor)
{
	if (nor->flags & SNOR_F_HAS_LOCK)
		return spi_nor_unlock(&nor->mtd, 0, nor->params.size);

	return 0;
}

static int spi_nor_init(struct spi_nor *nor)
{
	int err;

	err = spi_nor_quad_enable(nor);
	if (err) {
		dev_dbg(nor->dev, "quad mode not supported\n");
		return err;
	}

	err = spi_nor_unlock_all(nor);
	if (err) {
		dev_dbg(nor->dev, "Failed to unlock the entire flash memory array\n");
		return err;
	}

	if (nor->addr_width == 4 && !(nor->flags & SNOR_F_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.
		 */
		WARN_ONCE(nor->flags & SNOR_F_BROKEN_RESET,
			  "enabling reset hack; may not recover from unexpected reboots\n");
		nor->params.set_4byte(nor, true);
	}

	return 0;
}

/* mtd resume handler */
static void spi_nor_resume(struct mtd_info *mtd)
{
	struct spi_nor *nor = mtd_to_spi_nor(mtd);
	struct device *dev = nor->dev;
	int ret;

	/* re-initialize the nor chip */
	ret = spi_nor_init(nor);
	if (ret)
		dev_err(dev, "resume() failed\n");
}

void spi_nor_restore(struct spi_nor *nor)
{
	/* restore the addressing mode */
	if (nor->addr_width == 4 && !(nor->flags & SNOR_F_4B_OPCODES) &&
	    nor->flags & SNOR_F_BROKEN_RESET)
		nor->params.set_4byte(nor, false);
}
EXPORT_SYMBOL_GPL(spi_nor_restore);

static const struct flash_info *spi_nor_match_id(const char *name)
{
	const struct flash_info *id = spi_nor_ids;

	while (id->name) {
		if (!strcmp(name, id->name))
			return id;
		id++;
	}
	return NULL;
}

static int spi_nor_set_addr_width(struct spi_nor *nor)
{
	if (nor->addr_width) {
		/* already configured from SFDP */
	} else if (nor->info->addr_width) {
		nor->addr_width = nor->info->addr_width;
	} else if (nor->mtd.size > 0x1000000) {
		/* enable 4-byte addressing if the device exceeds 16MiB */
		nor->addr_width = 4;
	} 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;
	}

	/* Set 4byte opcodes when possible. */
	if (nor->addr_width == 4 && nor->flags & SNOR_F_4B_OPCODES &&
	    !(nor->flags & SNOR_F_HAS_4BAIT))
		spi_nor_set_4byte_opcodes(nor);

	return 0;
}

static void spi_nor_debugfs_init(struct spi_nor *nor,
				 const struct flash_info *info)
{
	struct mtd_info *mtd = &nor->mtd;

	mtd->dbg.partname = info->name;
	mtd->dbg.partid = devm_kasprintf(nor->dev, GFP_KERNEL, "spi-nor:%*phN",
					 info->id_len, info->id);
}

static const struct flash_info *spi_nor_get_flash_info(struct spi_nor *nor,
						       const char *name)
{
	const struct flash_info *info = NULL;

	if (name)
		info = spi_nor_match_id(name);
	/* Try to auto-detect if chip name wasn't specified or not found */
	if (!info)
		info = spi_nor_read_id(nor);
	if (IS_ERR_OR_NULL(info))
		return ERR_PTR(-ENOENT);

	/*
	 * If caller has specified name of flash model that can normally be
	 * detected using JEDEC, let's verify it.
	 */
	if (name && info->id_len) {
		const struct flash_info *jinfo;

		jinfo = spi_nor_read_id(nor);
		if (IS_ERR(jinfo)) {
			return jinfo;
		} else if (jinfo != info) {
			/*
			 * JEDEC knows better, so overwrite platform ID. We
			 * can't trust partitions any longer, but we'll let
			 * mtd apply them anyway, since some partitions may be
			 * marked read-only, and we don't want to lose that
			 * information, even if it's not 100% accurate.
			 */
			dev_warn(nor->dev, "found %s, expected %s\n",
				 jinfo->name, info->name);
			info = jinfo;
		}
	}

	return info;
}

int spi_nor_scan(struct spi_nor *nor, const char *name,
		 const struct spi_nor_hwcaps *hwcaps)
{
	const struct flash_info *info;
	struct device *dev = nor->dev;
	struct mtd_info *mtd = &nor->mtd;
	struct device_node *np = spi_nor_get_flash_node(nor);
	struct spi_nor_flash_parameter *params = &nor->params;
	int ret;
	int i;

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

	/*
	 * We need the bounce buffer early to read/write registers when going
	 * through the spi-mem layer (buffers have to be DMA-able).
	 * For spi-mem drivers, we'll reallocate a new buffer if
	 * nor->page_size turns out to be greater than PAGE_SIZE (which
	 * shouldn't happen before long since NOR pages are usually less
	 * than 1KB) after spi_nor_scan() returns.
	 */
	nor->bouncebuf_size = PAGE_SIZE;
	nor->bouncebuf = devm_kmalloc(dev, nor->bouncebuf_size,
				      GFP_KERNEL);
	if (!nor->bouncebuf)
		return -ENOMEM;

	info = spi_nor_get_flash_info(nor, name);
	if (IS_ERR(info))
		return PTR_ERR(info);

	nor->info = info;

	spi_nor_debugfs_init(nor, info);

	mutex_init(&nor->lock);

	/*
	 * Make sure the XSR_RDY flag is set before calling
	 * spi_nor_wait_till_ready(). Xilinx S3AN share MFR
	 * with Atmel spi-nor
	 */
	if (info->flags & SPI_NOR_XSR_RDY)
		nor->flags |=  SNOR_F_READY_XSR_RDY;

	if (info->flags & SPI_NOR_HAS_LOCK)
		nor->flags |= SNOR_F_HAS_LOCK;

	/* Init flash parameters based on flash_info struct and SFDP */
	spi_nor_init_params(nor);

	if (!mtd->name)
		mtd->name = dev_name(dev);
	mtd->priv = nor;
	mtd->type = MTD_NORFLASH;
	mtd->writesize = 1;
	mtd->flags = MTD_CAP_NORFLASH;
	mtd->size = params->size;
	mtd->_erase = spi_nor_erase;
	mtd->_read = spi_nor_read;
	mtd->_resume = spi_nor_resume;

	if (nor->params.locking_ops) {
		mtd->_lock = spi_nor_lock;
		mtd->_unlock = spi_nor_unlock;
		mtd->_is_locked = spi_nor_is_locked;
	}

	/* sst nor chips use AAI word program */
	if (info->flags & SST_WRITE)
		mtd->_write = sst_write;
	else
		mtd->_write = spi_nor_write;

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

	if (info->flags & SPI_NOR_NO_ERASE)
		mtd->flags |= MTD_NO_ERASE;

	mtd->dev.parent = dev;
	nor->page_size = params->page_size;
	mtd->writebufsize = nor->page_size;

	if (of_property_read_bool(np, "broken-flash-reset"))
		nor->flags |= SNOR_F_BROKEN_RESET;

	/*
	 * 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.
	 */
	ret = spi_nor_setup(nor, hwcaps);
	if (ret)
		return ret;

	if (info->flags & SPI_NOR_4B_OPCODES)
		nor->flags |= SNOR_F_4B_OPCODES;

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

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

	dev_info(dev, "%s (%lld Kbytes)\n", info->name,
			(long long)mtd->size >> 10);

	dev_dbg(dev,
		"mtd .name = %s, .size = 0x%llx (%lldMiB), "
		".erasesize = 0x%.8x (%uKiB) .numeraseregions = %d\n",
		mtd->name, (long long)mtd->size, (long long)(mtd->size >> 20),
		mtd->erasesize, mtd->erasesize / 1024, mtd->numeraseregions);

	if (mtd->numeraseregions)
		for (i = 0; i < mtd->numeraseregions; i++)
			dev_dbg(dev,
				"mtd.eraseregions[%d] = { .offset = 0x%llx, "
				".erasesize = 0x%.8x (%uKiB), "
				".numblocks = %d }\n",
				i, (long long)mtd->eraseregions[i].offset,
				mtd->eraseregions[i].erasesize,
				mtd->eraseregions[i].erasesize / 1024,
				mtd->eraseregions[i].numblocks);
	return 0;
}
EXPORT_SYMBOL_GPL(spi_nor_scan);

static int spi_nor_probe(struct spi_mem *spimem)
{
	struct spi_device *spi = spimem->spi;
	struct flash_platform_data *data = dev_get_platdata(&spi->dev);
	struct spi_nor *nor;
	/*
	 * Enable all caps by default. The core will mask them after
	 * checking what's really supported using spi_mem_supports_op().
	 */
	const struct spi_nor_hwcaps hwcaps = { .mask = SNOR_HWCAPS_ALL };
	char *flash_name;
	int ret;

	nor = devm_kzalloc(&spi->dev, sizeof(*nor), GFP_KERNEL);
	if (!nor)
		return -ENOMEM;

	nor->spimem = spimem;
	nor->dev = &spi->dev;
	spi_nor_set_flash_node(nor, spi->dev.of_node);

	spi_mem_set_drvdata(spimem, nor);

	if (data && data->name)
		nor->mtd.name = data->name;

	if (!nor->mtd.name)
		nor->mtd.name = spi_mem_get_name(spimem);

	/*
	 * For some (historical?) reason many platforms provide two different
	 * names in flash_platform_data: "name" and "type". Quite often name is
	 * set to "m25p80" and then "type" provides a real chip name.
	 * If that's the case, respect "type" and ignore a "name".
	 */
	if (data && data->type)
		flash_name = data->type;
	else if (!strcmp(spi->modalias, "spi-nor"))
		flash_name = NULL; /* auto-detect */
	else
		flash_name = spi->modalias;

	ret = spi_nor_scan(nor, flash_name, &hwcaps);
	if (ret)
		return ret;

	/*
	 * None of the existing parts have > 512B pages, but let's play safe
	 * and add this logic so that if anyone ever adds support for such
	 * a NOR we don't end up with buffer overflows.
	 */
	if (nor->page_size > PAGE_SIZE) {
		nor->bouncebuf_size = nor->page_size;
		devm_kfree(nor->dev, nor->bouncebuf);
		nor->bouncebuf = devm_kmalloc(nor->dev,
					      nor->bouncebuf_size,
					      GFP_KERNEL);
		if (!nor->bouncebuf)
			return -ENOMEM;
	}

	return mtd_device_register(&nor->mtd, data ? data->parts : NULL,
				   data ? data->nr_parts : 0);
}

static int spi_nor_remove(struct spi_mem *spimem)
{
	struct spi_nor *nor = spi_mem_get_drvdata(spimem);

	spi_nor_restore(nor);

	/* Clean up MTD stuff. */
	return mtd_device_unregister(&nor->mtd);
}

static void spi_nor_shutdown(struct spi_mem *spimem)
{
	struct spi_nor *nor = spi_mem_get_drvdata(spimem);

	spi_nor_restore(nor);
}

/*
 * Do NOT add to this array without reading the following:
 *
 * Historically, many flash devices are bound to this driver by their name. But
 * since most of these flash are compatible to some extent, and their
 * differences can often be differentiated by the JEDEC read-ID command, we
 * encourage new users to add support to the spi-nor library, and simply bind
 * against a generic string here (e.g., "jedec,spi-nor").
 *
 * Many flash names are kept here in this list (as well as in spi-nor.c) to
 * keep them available as module aliases for existing platforms.
 */
static const struct spi_device_id spi_nor_dev_ids[] = {
	/*
	 * Allow non-DT platform devices to bind to the "spi-nor" modalias, and
	 * hack around the fact that the SPI core does not provide uevent
	 * matching for .of_match_table
	 */
	{"spi-nor"},

	/*
	 * Entries not used in DTs that should be safe to drop after replacing
	 * them with "spi-nor" in platform data.
	 */
	{"s25sl064a"},	{"w25x16"},	{"m25p10"},	{"m25px64"},

	/*
	 * Entries that were used in DTs without "jedec,spi-nor" fallback and
	 * should be kept for backward compatibility.
	 */
	{"at25df321a"},	{"at25df641"},	{"at26df081a"},
	{"mx25l4005a"},	{"mx25l1606e"},	{"mx25l6405d"},	{"mx25l12805d"},
	{"mx25l25635e"},{"mx66l51235l"},
	{"n25q064"},	{"n25q128a11"},	{"n25q128a13"},	{"n25q512a"},
	{"s25fl256s1"},	{"s25fl512s"},	{"s25sl12801"},	{"s25fl008k"},
	{"s25fl064k"},
	{"sst25vf040b"},{"sst25vf016b"},{"sst25vf032b"},{"sst25wf040"},
	{"m25p40"},	{"m25p80"},	{"m25p16"},	{"m25p32"},
	{"m25p64"},	{"m25p128"},
	{"w25x80"},	{"w25x32"},	{"w25q32"},	{"w25q32dw"},
	{"w25q80bl"},	{"w25q128"},	{"w25q256"},

	/* Flashes that can't be detected using JEDEC */
	{"m25p05-nonjedec"},	{"m25p10-nonjedec"},	{"m25p20-nonjedec"},
	{"m25p40-nonjedec"},	{"m25p80-nonjedec"},	{"m25p16-nonjedec"},
	{"m25p32-nonjedec"},	{"m25p64-nonjedec"},	{"m25p128-nonjedec"},

	/* Everspin MRAMs (non-JEDEC) */
	{ "mr25h128" }, /* 128 Kib, 40 MHz */
	{ "mr25h256" }, /* 256 Kib, 40 MHz */
	{ "mr25h10" },  /*   1 Mib, 40 MHz */
	{ "mr25h40" },  /*   4 Mib, 40 MHz */

	{ },
};
MODULE_DEVICE_TABLE(spi, spi_nor_dev_ids);

static const struct of_device_id spi_nor_of_table[] = {
	/*
	 * Generic compatibility for SPI NOR that can be identified by the
	 * JEDEC READ ID opcode (0x9F). Use this, if possible.
	 */
	{ .compatible = "jedec,spi-nor" },
	{ /* sentinel */ },
};
MODULE_DEVICE_TABLE(of, spi_nor_of_table);

/*
 * REVISIT: many of these chips have deep power-down modes, which
 * should clearly be entered on suspend() to minimize power use.
 * And also when they're otherwise idle...
 */
static struct spi_mem_driver spi_nor_driver = {
	.spidrv = {
		.driver = {
			.name = "spi-nor",
			.of_match_table = spi_nor_of_table,
		},
		.id_table = spi_nor_dev_ids,
	},
	.probe = spi_nor_probe,
	.remove = spi_nor_remove,
	.shutdown = spi_nor_shutdown,
};
module_spi_mem_driver(spi_nor_driver);

MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Huang Shijie <shijie8@gmail.com>");
MODULE_AUTHOR("Mike Lavender");
MODULE_DESCRIPTION("framework for SPI NOR");