include/linux/mtd/nand.h

/*
 *  linux/include/linux/mtd/nand.h
 *
 *  Copyright © 2000-2010 David Woodhouse <dwmw2@infradead.org>
 *                        Steven J. Hill <sjhill@realitydiluted.com>
 *		          Thomas Gleixner <tglx@linutronix.de>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * Info:
 *	Contains standard defines and IDs for NAND flash devices
 *
 * Changelog:
 *	See git changelog.
 */
#ifndef __LINUX_MTD_NAND_H
#define __LINUX_MTD_NAND_H

#include <linux/wait.h>
#include <linux/spinlock.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/flashchip.h>
#include <linux/mtd/bbm.h>

struct mtd_info;
struct nand_flash_dev;
/* Scan and identify a NAND device */
extern int nand_scan(struct mtd_info *mtd, int max_chips);
/*
 * Separate phases of nand_scan(), allowing board driver to intervene
 * and override command or ECC setup according to flash type.
 */
extern int nand_scan_ident(struct mtd_info *mtd, int max_chips,
			   struct nand_flash_dev *table);
extern int nand_scan_tail(struct mtd_info *mtd);

/* Free resources held by the NAND device */
extern void nand_release(struct mtd_info *mtd);

/* Internal helper for board drivers which need to override command function */
extern void nand_wait_ready(struct mtd_info *mtd);

/* locks all blockes present in the device */
extern int nand_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len);

/* unlocks specified locked blockes */
extern int nand_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t len);

/* The maximum number of NAND chips in an array */
#define NAND_MAX_CHIPS		8

/*
 * This constant declares the max. oobsize / page, which
 * is supported now. If you add a chip with bigger oobsize/page
 * adjust this accordingly.
 */
#define NAND_MAX_OOBSIZE	576
#define NAND_MAX_PAGESIZE	8192

/*
 * Constants for hardware specific CLE/ALE/NCE function
 *
 * These are bits which can be or'ed to set/clear multiple
 * bits in one go.
 */
/* Select the chip by setting nCE to low */
#define NAND_NCE		0x01
/* Select the command latch by setting CLE to high */
#define NAND_CLE		0x02
/* Select the address latch by setting ALE to high */
#define NAND_ALE		0x04

#define NAND_CTRL_CLE		(NAND_NCE | NAND_CLE)
#define NAND_CTRL_ALE		(NAND_NCE | NAND_ALE)
#define NAND_CTRL_CHANGE	0x80

/*
 * Standard NAND flash commands
 */
#define NAND_CMD_READ0		0
#define NAND_CMD_READ1		1
#define NAND_CMD_RNDOUT		5
#define NAND_CMD_PAGEPROG	0x10
#define NAND_CMD_READOOB	0x50
#define NAND_CMD_ERASE1		0x60
#define NAND_CMD_STATUS		0x70
#define NAND_CMD_STATUS_MULTI	0x71
#define NAND_CMD_SEQIN		0x80
#define NAND_CMD_RNDIN		0x85
#define NAND_CMD_READID		0x90
#define NAND_CMD_ERASE2		0xd0
#define NAND_CMD_PARAM		0xec
#define NAND_CMD_RESET		0xff

#define NAND_CMD_LOCK		0x2a
#define NAND_CMD_UNLOCK1	0x23
#define NAND_CMD_UNLOCK2	0x24

/* Extended commands for large page devices */
#define NAND_CMD_READSTART	0x30
#define NAND_CMD_RNDOUTSTART	0xE0
#define NAND_CMD_CACHEDPROG	0x15

/* Extended commands for AG-AND device */
/*
 * Note: the command for NAND_CMD_DEPLETE1 is really 0x00 but
 *       there is no way to distinguish that from NAND_CMD_READ0
 *       until the remaining sequence of commands has been completed
 *       so add a high order bit and mask it off in the command.
 */
#define NAND_CMD_DEPLETE1	0x100
#define NAND_CMD_DEPLETE2	0x38
#define NAND_CMD_STATUS_MULTI	0x71
#define NAND_CMD_STATUS_ERROR	0x72
/* multi-bank error status (banks 0-3) */
#define NAND_CMD_STATUS_ERROR0	0x73
#define NAND_CMD_STATUS_ERROR1	0x74
#define NAND_CMD_STATUS_ERROR2	0x75
#define NAND_CMD_STATUS_ERROR3	0x76
#define NAND_CMD_STATUS_RESET	0x7f
#define NAND_CMD_STATUS_CLEAR	0xff

#define NAND_CMD_NONE		-1

/* Status bits */
#define NAND_STATUS_FAIL	0x01
#define NAND_STATUS_FAIL_N1	0x02
#define NAND_STATUS_TRUE_READY	0x20
#define NAND_STATUS_READY	0x40
#define NAND_STATUS_WP		0x80

/*
 * Constants for ECC_MODES
 */
typedef enum {
	NAND_ECC_NONE,
	NAND_ECC_SOFT,
	NAND_ECC_HW,
	NAND_ECC_HW_SYNDROME,
	NAND_ECC_HW_OOB_FIRST,
} nand_ecc_modes_t;

/*
 * Constants for Hardware ECC
 */
/* Reset Hardware ECC for read */
#define NAND_ECC_READ		0
/* Reset Hardware ECC for write */
#define NAND_ECC_WRITE		1
/* Enable Hardware ECC before syndrom is read back from flash */
#define NAND_ECC_READSYN	2

/* Bit mask for flags passed to do_nand_read_ecc */
#define NAND_GET_DEVICE		0x80


/*
 * Option constants for bizarre disfunctionality and real
 * features.
 */
/* Chip can not auto increment pages */
#define NAND_NO_AUTOINCR	0x00000001
/* Buswitdh is 16 bit */
#define NAND_BUSWIDTH_16	0x00000002
/* Device supports partial programming without padding */
#define NAND_NO_PADDING		0x00000004
/* Chip has cache program function */
#define NAND_CACHEPRG		0x00000008
/* Chip has copy back function */
#define NAND_COPYBACK		0x00000010
/*
 * AND Chip which has 4 banks and a confusing page / block
 * assignment. See Renesas datasheet for further information.
 */
#define NAND_IS_AND		0x00000020
/*
 * Chip has a array of 4 pages which can be read without
 * additional ready /busy waits.
 */
#define NAND_4PAGE_ARRAY	0x00000040
/*
 * Chip requires that BBT is periodically rewritten to prevent
 * bits from adjacent blocks from 'leaking' in altering data.
 * This happens with the Renesas AG-AND chips, possibly others.
 */
#define BBT_AUTO_REFRESH	0x00000080
/*
 * Chip does not require ready check on read. True
 * for all large page devices, as they do not support
 * autoincrement.
 */
#define NAND_NO_READRDY		0x00000100
/* Chip does not allow subpage writes */
#define NAND_NO_SUBPAGE_WRITE	0x00000200

/* Device is one of 'new' xD cards that expose fake nand command set */
#define NAND_BROKEN_XD		0x00000400

/* Device behaves just like nand, but is readonly */
#define NAND_ROM		0x00000800

/* Options valid for Samsung large page devices */
#define NAND_SAMSUNG_LP_OPTIONS \
	(NAND_NO_PADDING | NAND_CACHEPRG | NAND_COPYBACK)

/* Macros to identify the above */
#define NAND_CANAUTOINCR(chip) (!(chip->options & NAND_NO_AUTOINCR))
#define NAND_MUST_PAD(chip) (!(chip->options & NAND_NO_PADDING))
#define NAND_HAS_CACHEPROG(chip) ((chip->options & NAND_CACHEPRG))
#define NAND_HAS_COPYBACK(chip) ((chip->options & NAND_COPYBACK))
/* Large page NAND with SOFT_ECC should support subpage reads */
#define NAND_SUBPAGE_READ(chip) ((chip->ecc.mode == NAND_ECC_SOFT) \
					&& (chip->page_shift > 9))

/* Mask to zero out the chip options, which come from the id table */
#define NAND_CHIPOPTIONS_MSK	(0x0000ffff & ~NAND_NO_AUTOINCR)

/* Non chip related options */
/*
 * Use a flash based bad block table. OOB identifier is saved in OOB area.
 * This option is passed to the default bad block table function.
 */
#define NAND_USE_FLASH_BBT	0x00010000
/* This option skips the bbt scan during initialization. */
#define NAND_SKIP_BBTSCAN	0x00020000
/*
 * This option is defined if the board driver allocates its own buffers
 * (e.g. because it needs them DMA-coherent).
 */
#define NAND_OWN_BUFFERS	0x00040000
/* Chip may not exist, so silence any errors in scan */
#define NAND_SCAN_SILENT_NODEV	0x00080000
/*
 * If passed additionally to NAND_USE_FLASH_BBT then BBT code will not touch
 * the OOB area.
 */
#define NAND_USE_FLASH_BBT_NO_OOB	0x00100000
/* Create an empty BBT with no vendor information if the BBT is available */
#define NAND_CREATE_EMPTY_BBT		0x00200000

/* Options set by nand scan */
/* Nand scan has allocated controller struct */
#define NAND_CONTROLLER_ALLOC	0x80000000

/* Cell info constants */
#define NAND_CI_CHIPNR_MSK	0x03
#define NAND_CI_CELLTYPE_MSK	0x0C

/* Keep gcc happy */
struct nand_chip;

struct nand_onfi_params {
	/* rev info and features block */
	/* 'O' 'N' 'F' 'I'  */
	u8 sig[4];
	__le16 revision;
	__le16 features;
	__le16 opt_cmd;
	u8 reserved[22];

	/* manufacturer information block */
	char manufacturer[12];
	char model[20];
	u8 jedec_id;
	__le16 date_code;
	u8 reserved2[13];

	/* memory organization block */
	__le32 byte_per_page;
	__le16 spare_bytes_per_page;
	__le32 data_bytes_per_ppage;
	__le16 spare_bytes_per_ppage;
	__le32 pages_per_block;
	__le32 blocks_per_lun;
	u8 lun_count;
	u8 addr_cycles;
	u8 bits_per_cell;
	__le16 bb_per_lun;
	__le16 block_endurance;
	u8 guaranteed_good_blocks;
	__le16 guaranteed_block_endurance;
	u8 programs_per_page;
	u8 ppage_attr;
	u8 ecc_bits;
	u8 interleaved_bits;
	u8 interleaved_ops;
	u8 reserved3[13];

	/* electrical parameter block */
	u8 io_pin_capacitance_max;
	__le16 async_timing_mode;
	__le16 program_cache_timing_mode;
	__le16 t_prog;
	__le16 t_bers;
	__le16 t_r;
	__le16 t_ccs;
	__le16 src_sync_timing_mode;
	__le16 src_ssync_features;
	__le16 clk_pin_capacitance_typ;
	__le16 io_pin_capacitance_typ;
	__le16 input_pin_capacitance_typ;
	u8 input_pin_capacitance_max;
	u8 driver_strenght_support;
	__le16 t_int_r;
	__le16 t_ald;
	u8 reserved4[7];

	/* vendor */
	u8 reserved5[90];

	__le16 crc;
} __attribute__((packed));

#define ONFI_CRC_BASE	0x4F4E

/**
 * struct nand_hw_control - Control structure for hardware controller (e.g ECC generator) shared among independent devices
 * @lock:               protection lock
 * @active:		the mtd device which holds the controller currently
 * @wq:			wait queue to sleep on if a NAND operation is in
 *			progress used instead of the per chip wait queue
 *			when a hw controller is available.
 */
struct nand_hw_control {
	spinlock_t lock;
	struct nand_chip *active;
	wait_queue_head_t wq;
};

/**
 * struct nand_ecc_ctrl - Control structure for ecc
 * @mode:	ecc mode
 * @steps:	number of ecc steps per page
 * @size:	data bytes per ecc step
 * @bytes:	ecc bytes per step
 * @total:	total number of ecc bytes per page
 * @prepad:	padding information for syndrome based ecc generators
 * @postpad:	padding information for syndrome based ecc generators
 * @layout:	ECC layout control struct pointer
 * @hwctl:	function to control hardware ecc generator. Must only
 *		be provided if an hardware ECC is available
 * @calculate:	function for ecc calculation or readback from ecc hardware
 * @correct:	function for ecc correction, matching to ecc generator (sw/hw)
 * @read_page_raw:	function to read a raw page without ECC
 * @write_page_raw:	function to write a raw page without ECC
 * @read_page:	function to read a page according to the ecc generator
 *		requirements.
 * @read_subpage:	function to read parts of the page covered by ECC.
 * @write_page:	function to write a page according to the ecc generator
 *		requirements.
 * @read_oob:	function to read chip OOB data
 * @write_oob:	function to write chip OOB data
 */
struct nand_ecc_ctrl {
	nand_ecc_modes_t mode;
	int steps;
	int size;
	int bytes;
	int total;
	int prepad;
	int postpad;
	struct nand_ecclayout	*layout;
	void (*hwctl)(struct mtd_info *mtd, int mode);
	int (*calculate)(struct mtd_info *mtd, const uint8_t *dat,
			uint8_t *ecc_code);
	int (*correct)(struct mtd_info *mtd, uint8_t *dat, uint8_t *read_ecc,
			uint8_t *calc_ecc);
	int (*read_page_raw)(struct mtd_info *mtd, struct nand_chip *chip,
			uint8_t *buf, int page);
	void (*write_page_raw)(struct mtd_info *mtd, struct nand_chip *chip,
			const uint8_t *buf);
	int (*read_page)(struct mtd_info *mtd, struct nand_chip *chip,
			uint8_t *buf, int page);
	int (*read_subpage)(struct mtd_info *mtd, struct nand_chip *chip,
			uint32_t offs, uint32_t len, uint8_t *buf);
	void (*write_page)(struct mtd_info *mtd, struct nand_chip *chip,
			const uint8_t *buf);
	int (*read_oob)(struct mtd_info *mtd, struct nand_chip *chip, int page,
			int sndcmd);
	int (*write_oob)(struct mtd_info *mtd, struct nand_chip *chip,
			int page);
};

/**
 * struct nand_buffers - buffer structure for read/write
 * @ecccalc:	buffer for calculated ecc
 * @ecccode:	buffer for ecc read from flash
 * @databuf:	buffer for data - dynamically sized
 *
 * Do not change the order of buffers. databuf and oobrbuf must be in
 * consecutive order.
 */
struct nand_buffers {
	uint8_t	ecccalc[NAND_MAX_OOBSIZE];
	uint8_t	ecccode[NAND_MAX_OOBSIZE];
	uint8_t databuf[NAND_MAX_PAGESIZE + NAND_MAX_OOBSIZE];
};

/**
 * struct nand_chip - NAND Private Flash Chip Data
 * @IO_ADDR_R:		[BOARDSPECIFIC] address to read the 8 I/O lines of the
 *			flash device
 * @IO_ADDR_W:		[BOARDSPECIFIC] address to write the 8 I/O lines of the
 *			flash device.
 * @read_byte:		[REPLACEABLE] read one byte from the chip
 * @read_word:		[REPLACEABLE] read one word from the chip
 * @write_buf:		[REPLACEABLE] write data from the buffer to the chip
 * @read_buf:		[REPLACEABLE] read data from the chip into the buffer
 * @verify_buf:		[REPLACEABLE] verify buffer contents against the chip
 *			data.
 * @select_chip:	[REPLACEABLE] select chip nr
 * @block_bad:		[REPLACEABLE] check, if the block is bad
 * @block_markbad:	[REPLACEABLE] mark the block bad
 * @cmd_ctrl:		[BOARDSPECIFIC] hardwarespecific funtion for controlling
 *			ALE/CLE/nCE. Also used to write command and address
 * @init_size:		[BOARDSPECIFIC] hardwarespecific funtion for setting
 *			mtd->oobsize, mtd->writesize and so on.
 *			@id_data contains the 8 bytes values of NAND_CMD_READID.
 *			Return with the bus width.
 * @dev_ready:		[BOARDSPECIFIC] hardwarespecific function for accesing
 *			device ready/busy line. If set to NULL no access to
 *			ready/busy is available and the ready/busy information
 *			is read from the chip status register.
 * @cmdfunc:		[REPLACEABLE] hardwarespecific function for writing
 *			commands to the chip.
 * @waitfunc:		[REPLACEABLE] hardwarespecific function for wait on
 *			ready.
 * @ecc:		[BOARDSPECIFIC] ecc control ctructure
 * @buffers:		buffer structure for read/write
 * @hwcontrol:		platform-specific hardware control structure
 * @ops:		oob operation operands
 * @erase_cmd:		[INTERN] erase command write function, selectable due
 *			to AND support.
 * @scan_bbt:		[REPLACEABLE] function to scan bad block table
 * @chip_delay:		[BOARDSPECIFIC] chip dependent delay for transfering
 *			data from array to read regs (tR).
 * @state:		[INTERN] the current state of the NAND device
 * @oob_poi:		poison value buffer
 * @page_shift:		[INTERN] number of address bits in a page (column
 *			address bits).
 * @phys_erase_shift:	[INTERN] number of address bits in a physical eraseblock
 * @bbt_erase_shift:	[INTERN] number of address bits in a bbt entry
 * @chip_shift:		[INTERN] number of address bits in one chip
 * @options:		[BOARDSPECIFIC] various chip options. They can partly
 *			be set to inform nand_scan about special functionality.
 *			See the defines for further explanation.
 * @badblockpos:	[INTERN] position of the bad block marker in the oob
 *			area.
 * @cellinfo:		[INTERN] MLC/multichip data from chip ident
 * @numchips:		[INTERN] number of physical chips
 * @chipsize:		[INTERN] the size of one chip for multichip arrays
 * @pagemask:		[INTERN] page number mask = number of (pages / chip) - 1
 * @pagebuf:		[INTERN] holds the pagenumber which is currently in
 *			data_buf.
 * @subpagesize:	[INTERN] holds the subpagesize
 * @onfi_version:	[INTERN] holds the chip ONFI version (BCD encoded),
 *			non 0 if ONFI supported.
 * @onfi_params:	[INTERN] holds the ONFI page parameter when ONFI is
 *			supported, 0 otherwise.
 * @ecclayout:		[REPLACEABLE] the default ecc placement scheme
 * @bbt:		[INTERN] bad block table pointer
 * @bbt_td:		[REPLACEABLE] bad block table descriptor for flash
 *			lookup.
 * @bbt_md:		[REPLACEABLE] bad block table mirror descriptor
 * @badblock_pattern:	[REPLACEABLE] bad block scan pattern used for initial
 *			bad block scan.
 * @controller:		[REPLACEABLE] a pointer to a hardware controller
 *			structure which is shared among multiple independend
 *			devices.
 * @priv:		[OPTIONAL] pointer to private chip date
 * @errstat:		[OPTIONAL] hardware specific function to perform
 *			additional error status checks (determine if errors are
 *			correctable).
 * @write_page:		[REPLACEABLE] High-level page write function
 */

struct nand_chip {
	void __iomem *IO_ADDR_R;
	void __iomem *IO_ADDR_W;

	uint8_t (*read_byte)(struct mtd_info *mtd);
	u16 (*read_word)(struct mtd_info *mtd);
	void (*write_buf)(struct mtd_info *mtd, const uint8_t *buf, int len);
	void (*read_buf)(struct mtd_info *mtd, uint8_t *buf, int len);
	int (*verify_buf)(struct mtd_info *mtd, const uint8_t *buf, int len);
	void (*select_chip)(struct mtd_info *mtd, int chip);
	int (*block_bad)(struct mtd_info *mtd, loff_t ofs, int getchip);
	int (*block_markbad)(struct mtd_info *mtd, loff_t ofs);
	void (*cmd_ctrl)(struct mtd_info *mtd, int dat, unsigned int ctrl);
	int (*init_size)(struct mtd_info *mtd, struct nand_chip *this,
			u8 *id_data);
	int (*dev_ready)(struct mtd_info *mtd);
	void (*cmdfunc)(struct mtd_info *mtd, unsigned command, int column,
			int page_addr);
	int(*waitfunc)(struct mtd_info *mtd, struct nand_chip *this);
	void (*erase_cmd)(struct mtd_info *mtd, int page);
	int (*scan_bbt)(struct mtd_info *mtd);
	int (*errstat)(struct mtd_info *mtd, struct nand_chip *this, int state,
			int status, int page);
	int (*write_page)(struct mtd_info *mtd, struct nand_chip *chip,
			const uint8_t *buf, int page, int cached, int raw);

	int chip_delay;
	unsigned int options;

	int page_shift;
	int phys_erase_shift;
	int bbt_erase_shift;
	int chip_shift;
	int numchips;
	uint64_t chipsize;
	int pagemask;
	int pagebuf;
	int subpagesize;
	uint8_t cellinfo;
	int badblockpos;
	int badblockbits;

	int onfi_version;
	struct nand_onfi_params	onfi_params;

	flstate_t state;

	uint8_t *oob_poi;
	struct nand_hw_control *controller;
	struct nand_ecclayout *ecclayout;

	struct nand_ecc_ctrl ecc;
	struct nand_buffers *buffers;
	struct nand_hw_control hwcontrol;

	struct mtd_oob_ops ops;

	uint8_t *bbt;
	struct nand_bbt_descr *bbt_td;
	struct nand_bbt_descr *bbt_md;

	struct nand_bbt_descr *badblock_pattern;

	void *priv;
};

/*
 * NAND Flash Manufacturer ID Codes
 */
#define NAND_MFR_TOSHIBA	0x98
#define NAND_MFR_SAMSUNG	0xec
#define NAND_MFR_FUJITSU	0x04
#define NAND_MFR_NATIONAL	0x8f
#define NAND_MFR_RENESAS	0x07
#define NAND_MFR_STMICRO	0x20
#define NAND_MFR_HYNIX		0xad
#define NAND_MFR_MICRON		0x2c
#define NAND_MFR_AMD		0x01

/**
 * struct nand_flash_dev - NAND Flash Device ID Structure
 * @name:	Identify the device type
 * @id:		device ID code
 * @pagesize:	Pagesize in bytes. Either 256 or 512 or 0
 *		If the pagesize is 0, then the real pagesize
 *		and the eraseize are determined from the
 *		extended id bytes in the chip
 * @erasesize:	Size of an erase block in the flash device.
 * @chipsize:	Total chipsize in Mega Bytes
 * @options:	Bitfield to store chip relevant options
 */
struct nand_flash_dev {
	char *name;
	int id;
	unsigned long pagesize;
	unsigned long chipsize;
	unsigned long erasesize;
	unsigned long options;
};

/**
 * struct nand_manufacturers - NAND Flash Manufacturer ID Structure
 * @name:	Manufacturer name
 * @id:		manufacturer ID code of device.
*/
struct nand_manufacturers {
	int id;
	char *name;
};

extern struct nand_flash_dev nand_flash_ids[];
extern struct nand_manufacturers nand_manuf_ids[];

extern int nand_scan_bbt(struct mtd_info *mtd, struct nand_bbt_descr *bd);
extern int nand_update_bbt(struct mtd_info *mtd, loff_t offs);
extern int nand_default_bbt(struct mtd_info *mtd);
extern int nand_isbad_bbt(struct mtd_info *mtd, loff_t offs, int allowbbt);
extern int nand_erase_nand(struct mtd_info *mtd, struct erase_info *instr,
			   int allowbbt);
extern int nand_do_read(struct mtd_info *mtd, loff_t from, size_t len,
			size_t *retlen, uint8_t *buf);

/**
 * struct platform_nand_chip - chip level device structure
 * @nr_chips:		max. number of chips to scan for
 * @chip_offset:	chip number offset
 * @nr_partitions:	number of partitions pointed to by partitions (or zero)
 * @partitions:		mtd partition list
 * @chip_delay:		R/B delay value in us
 * @options:		Option flags, e.g. 16bit buswidth
 * @ecclayout:		ecc layout info structure
 * @part_probe_types:	NULL-terminated array of probe types
 * @set_parts:		platform specific function to set partitions
 * @priv:		hardware controller specific settings
 */
struct platform_nand_chip {
	int nr_chips;
	int chip_offset;
	int nr_partitions;
	struct mtd_partition *partitions;
	struct nand_ecclayout *ecclayout;
	int chip_delay;
	unsigned int options;
	const char **part_probe_types;
	void (*set_parts)(uint64_t size, struct platform_nand_chip *chip);
	void *priv;
};

/* Keep gcc happy */
struct platform_device;

/**
 * struct platform_nand_ctrl - controller level device structure
 * @probe:		platform specific function to probe/setup hardware
 * @remove:		platform specific function to remove/teardown hardware
 * @hwcontrol:		platform specific hardware control structure
 * @dev_ready:		platform specific function to read ready/busy pin
 * @select_chip:	platform specific chip select function
 * @cmd_ctrl:		platform specific function for controlling
 *			ALE/CLE/nCE. Also used to write command and address
 * @write_buf:		platform specific function for write buffer
 * @read_buf:		platform specific function for read buffer
 * @priv:		private data to transport driver specific settings
 *
 * All fields are optional and depend on the hardware driver requirements
 */
struct platform_nand_ctrl {
	int (*probe)(struct platform_device *pdev);
	void (*remove)(struct platform_device *pdev);
	void (*hwcontrol)(struct mtd_info *mtd, int cmd);
	int (*dev_ready)(struct mtd_info *mtd);
	void (*select_chip)(struct mtd_info *mtd, int chip);
	void (*cmd_ctrl)(struct mtd_info *mtd, int dat, unsigned int ctrl);
	void (*write_buf)(struct mtd_info *mtd, const uint8_t *buf, int len);
	void (*read_buf)(struct mtd_info *mtd, uint8_t *buf, int len);
	void *priv;
};

/**
 * struct platform_nand_data - container structure for platform-specific data
 * @chip:		chip level chip structure
 * @ctrl:		controller level device structure
 */
struct platform_nand_data {
	struct platform_nand_chip chip;
	struct platform_nand_ctrl ctrl;
};

/* Some helpers to access the data structures */
static inline
struct platform_nand_chip *get_platform_nandchip(struct mtd_info *mtd)
{
	struct nand_chip *chip = mtd->priv;

	return chip->priv;
}

#endif /* __LINUX_MTD_NAND_H */