/*
 * Copyright © 1999-2010 David Woodhouse <dwmw2@infradead.org> et al.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *
 */

#ifndef __MTD_MTD_H__
#define __MTD_MTD_H__

#include <linux/types.h>
#include <linux/module.h>
#include <linux/uio.h>
#include <linux/notifier.h>
#include <linux/device.h>

#include <mtd/mtd-abi.h>

#include <asm/div64.h>

#define MTD_CHAR_MAJOR 90
#define MTD_BLOCK_MAJOR 31

#define MTD_ERASE_PENDING      	0x01
#define MTD_ERASING		0x02
#define MTD_ERASE_SUSPEND	0x04
#define MTD_ERASE_DONE          0x08
#define MTD_ERASE_FAILED        0x10

#define MTD_FAIL_ADDR_UNKNOWN -1LL

/* If the erase fails, fail_addr might indicate exactly which block failed.  If
   fail_addr = MTD_FAIL_ADDR_UNKNOWN, the failure was not at the device level or was not
   specific to any particular block. */
struct erase_info {
	struct mtd_info *mtd;
	uint64_t addr;
	uint64_t len;
	uint64_t fail_addr;
	u_long time;
	u_long retries;
	unsigned dev;
	unsigned cell;
	void (*callback) (struct erase_info *self);
	u_long priv;
	u_char state;
	struct erase_info *next;
};

struct mtd_erase_region_info {
	uint64_t offset;			/* At which this region starts, from the beginning of the MTD */
	uint32_t erasesize;		/* For this region */
	uint32_t numblocks;		/* Number of blocks of erasesize in this region */
	unsigned long *lockmap;		/* If keeping bitmap of locks */
};

/**
 * struct mtd_oob_ops - oob operation operands
 * @mode:	operation mode
 *
 * @len:	number of data bytes to write/read
 *
 * @retlen:	number of data bytes written/read
 *
 * @ooblen:	number of oob bytes to write/read
 * @oobretlen:	number of oob bytes written/read
 * @ooboffs:	offset of oob data in the oob area (only relevant when
 *		mode = MTD_OPS_PLACE_OOB or MTD_OPS_RAW)
 * @datbuf:	data buffer - if NULL only oob data are read/written
 * @oobbuf:	oob data buffer
 *
 * Note, it is allowed to read more than one OOB area at one go, but not write.
 * The interface assumes that the OOB write requests program only one page's
 * OOB area.
 */
struct mtd_oob_ops {
	unsigned int	mode;
	size_t		len;
	size_t		retlen;
	size_t		ooblen;
	size_t		oobretlen;
	uint32_t	ooboffs;
	uint8_t		*datbuf;
	uint8_t		*oobbuf;
};

#define MTD_MAX_OOBFREE_ENTRIES_LARGE	32
#define MTD_MAX_ECCPOS_ENTRIES_LARGE	448
/*
 * Internal ECC layout control structure. For historical reasons, there is a
 * similar, smaller struct nand_ecclayout_user (in mtd-abi.h) that is retained
 * for export to user-space via the ECCGETLAYOUT ioctl.
 * nand_ecclayout should be expandable in the future simply by the above macros.
 */
struct nand_ecclayout {
	__u32 eccbytes;
	__u32 eccpos[MTD_MAX_ECCPOS_ENTRIES_LARGE];
	__u32 oobavail;
	struct nand_oobfree oobfree[MTD_MAX_OOBFREE_ENTRIES_LARGE];
};

struct mtd_info {
	u_char type;
	uint32_t flags;
	uint64_t size;	 // Total size of the MTD

	/* "Major" erase size for the device. Naïve users may take this
	 * to be the only erase size available, or may use the more detailed
	 * information below if they desire
	 */
	uint32_t erasesize;
	/* Minimal writable flash unit size. In case of NOR flash it is 1 (even
	 * though individual bits can be cleared), in case of NAND flash it is
	 * one NAND page (or half, or one-fourths of it), in case of ECC-ed NOR
	 * it is of ECC block size, etc. It is illegal to have writesize = 0.
	 * Any driver registering a struct mtd_info must ensure a writesize of
	 * 1 or larger.
	 */
	uint32_t writesize;

	/*
	 * Size of the write buffer used by the MTD. MTD devices having a write
	 * buffer can write multiple writesize chunks at a time. E.g. while
	 * writing 4 * writesize bytes to a device with 2 * writesize bytes
	 * buffer the MTD driver can (but doesn't have to) do 2 writesize
	 * operations, but not 4. Currently, all NANDs have writebufsize
	 * equivalent to writesize (NAND page size). Some NOR flashes do have
	 * writebufsize greater than writesize.
	 */
	uint32_t writebufsize;

	uint32_t oobsize;   // Amount of OOB data per block (e.g. 16)
	uint32_t oobavail;  // Available OOB bytes per block

	/*
	 * If erasesize is a power of 2 then the shift is stored in
	 * erasesize_shift otherwise erasesize_shift is zero. Ditto writesize.
	 */
	unsigned int erasesize_shift;
	unsigned int writesize_shift;
	/* Masks based on erasesize_shift and writesize_shift */
	unsigned int erasesize_mask;
	unsigned int writesize_mask;

	// Kernel-only stuff starts here.
	const char *name;
	int index;

	/* ecc layout structure pointer - read only ! */
	struct nand_ecclayout *ecclayout;

	/* Data for variable erase regions. If numeraseregions is zero,
	 * it means that the whole device has erasesize as given above.
	 */
	int numeraseregions;
	struct mtd_erase_region_info *eraseregions;

	/*
	 * Erase is an asynchronous operation.  Device drivers are supposed
	 * to call instr->callback() whenever the operation completes, even
	 * if it completes with a failure.
	 * Callers are supposed to pass a callback function and wait for it
	 * to be called before writing to the block.
	 */
	int (*erase) (struct mtd_info *mtd, struct erase_info *instr);

	/* This stuff for eXecute-In-Place */
	/* phys is optional and may be set to NULL */
	int (*point) (struct mtd_info *mtd, loff_t from, size_t len,
			size_t *retlen, void **virt, resource_size_t *phys);

	/* We probably shouldn't allow XIP if the unpoint isn't a NULL */
	void (*unpoint) (struct mtd_info *mtd, loff_t from, size_t len);

	/* Allow NOMMU mmap() to directly map the device (if not NULL)
	 * - return the address to which the offset maps
	 * - return -ENOSYS to indicate refusal to do the mapping
	 */
	unsigned long (*get_unmapped_area) (struct mtd_info *mtd,
					    unsigned long len,
					    unsigned long offset,
					    unsigned long flags);

	/* Backing device capabilities for this device
	 * - provides mmap capabilities
	 */
	struct backing_dev_info *backing_dev_info;


	int (*read) (struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char *buf);
	int (*write) (struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen, const u_char *buf);

	/* In blackbox flight recorder like scenarios we want to make successful
	   writes in interrupt context. panic_write() is only intended to be
	   called when its known the kernel is about to panic and we need the
	   write to succeed. Since the kernel is not going to be running for much
	   longer, this function can break locks and delay to ensure the write
	   succeeds (but not sleep). */

	int (*panic_write) (struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen, const u_char *buf);

	int (*read_oob) (struct mtd_info *mtd, loff_t from,
			 struct mtd_oob_ops *ops);
	int (*write_oob) (struct mtd_info *mtd, loff_t to,
			 struct mtd_oob_ops *ops);

	/*
	 * Methods to access the protection register area, present in some
	 * flash devices. The user data is one time programmable but the
	 * factory data is read only.
	 */
	int (*get_fact_prot_info) (struct mtd_info *mtd, struct otp_info *buf, size_t len);
	int (*read_fact_prot_reg) (struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char *buf);
	int (*get_user_prot_info) (struct mtd_info *mtd, struct otp_info *buf, size_t len);
	int (*read_user_prot_reg) (struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char *buf);
	int (*write_user_prot_reg) (struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char *buf);
	int (*lock_user_prot_reg) (struct mtd_info *mtd, loff_t from, size_t len);

	/* kvec-based read/write methods.
	   NB: The 'count' parameter is the number of _vectors_, each of
	   which contains an (ofs, len) tuple.
	*/
	int (*writev) (struct mtd_info *mtd, const struct kvec *vecs, unsigned long count, loff_t to, size_t *retlen);

	/* Sync */
	void (*sync) (struct mtd_info *mtd);

	/* Chip-supported device locking */
	int (*lock) (struct mtd_info *mtd, loff_t ofs, uint64_t len);
	int (*unlock) (struct mtd_info *mtd, loff_t ofs, uint64_t len);
	int (*is_locked) (struct mtd_info *mtd, loff_t ofs, uint64_t len);

	/* Power Management functions */
	int (*suspend) (struct mtd_info *mtd);
	void (*resume) (struct mtd_info *mtd);

	/* Bad block management functions */
	int (*block_isbad) (struct mtd_info *mtd, loff_t ofs);
	int (*block_markbad) (struct mtd_info *mtd, loff_t ofs);

	struct notifier_block reboot_notifier;  /* default mode before reboot */

	/* ECC status information */
	struct mtd_ecc_stats ecc_stats;
	/* Subpage shift (NAND) */
	int subpage_sft;

	void *priv;

	struct module *owner;
	struct device dev;
	int usecount;

	/* If the driver is something smart, like UBI, it may need to maintain
	 * its own reference counting. The below functions are only for driver.
	 * The driver may register its callbacks. These callbacks are not
	 * supposed to be called by MTD users */
	int (*get_device) (struct mtd_info *mtd);
	void (*put_device) (struct mtd_info *mtd);
};

static inline struct mtd_info *dev_to_mtd(struct device *dev)
{
	return dev ? dev_get_drvdata(dev) : NULL;
}

static inline uint32_t mtd_div_by_eb(uint64_t sz, struct mtd_info *mtd)
{
	if (mtd->erasesize_shift)
		return sz >> mtd->erasesize_shift;
	do_div(sz, mtd->erasesize);
	return sz;
}

static inline uint32_t mtd_mod_by_eb(uint64_t sz, struct mtd_info *mtd)
{
	if (mtd->erasesize_shift)
		return sz & mtd->erasesize_mask;
	return do_div(sz, mtd->erasesize);
}

static inline uint32_t mtd_div_by_ws(uint64_t sz, struct mtd_info *mtd)
{
	if (mtd->writesize_shift)
		return sz >> mtd->writesize_shift;
	do_div(sz, mtd->writesize);
	return sz;
}

static inline uint32_t mtd_mod_by_ws(uint64_t sz, struct mtd_info *mtd)
{
	if (mtd->writesize_shift)
		return sz & mtd->writesize_mask;
	return do_div(sz, mtd->writesize);
}

	/* Kernel-side ioctl definitions */

extern int add_mtd_device(struct mtd_info *mtd);
extern int del_mtd_device (struct mtd_info *mtd);

extern struct mtd_info *get_mtd_device(struct mtd_info *mtd, int num);
extern int __get_mtd_device(struct mtd_info *mtd);
extern void __put_mtd_device(struct mtd_info *mtd);
extern struct mtd_info *get_mtd_device_nm(const char *name);
extern void put_mtd_device(struct mtd_info *mtd);


struct mtd_notifier {
	void (*add)(struct mtd_info *mtd);
	void (*remove)(struct mtd_info *mtd);
	struct list_head list;
};


extern void register_mtd_user (struct mtd_notifier *new);
extern int unregister_mtd_user (struct mtd_notifier *old);

int default_mtd_writev(struct mtd_info *mtd, const struct kvec *vecs,
		       unsigned long count, loff_t to, size_t *retlen);

int default_mtd_readv(struct mtd_info *mtd, struct kvec *vecs,
		      unsigned long count, loff_t from, size_t *retlen);

#ifdef CONFIG_MTD_PARTITIONS
void mtd_erase_callback(struct erase_info *instr);
#else
static inline void mtd_erase_callback(struct erase_info *instr)
{
	if (instr->callback)
		instr->callback(instr);
}
#endif

/*
 * Debugging macro and defines
 */
#define MTD_DEBUG_LEVEL0	(0)	/* Quiet   */
#define MTD_DEBUG_LEVEL1	(1)	/* Audible */
#define MTD_DEBUG_LEVEL2	(2)	/* Loud    */
#define MTD_DEBUG_LEVEL3	(3)	/* Noisy   */

#ifdef CONFIG_MTD_DEBUG
#define DEBUG(n, args...)				\
	do {						\
		if (n <= CONFIG_MTD_DEBUG_VERBOSE)	\
			printk(KERN_INFO args);		\
	} while(0)
#else /* CONFIG_MTD_DEBUG */
#define DEBUG(n, args...)				\
	do {						\
		if (0)					\
			printk(KERN_INFO args);		\
	} while(0)

#endif /* CONFIG_MTD_DEBUG */

static inline int mtd_is_bitflip(int err) {
	return err == -EUCLEAN;
}

static inline int mtd_is_eccerr(int err) {
	return err == -EBADMSG;
}

static inline int mtd_is_bitflip_or_eccerr(int err) {
	return mtd_is_bitflip(err) || mtd_is_eccerr(err);
}

#endif /* __MTD_MTD_H__ */