/* SPDX-License-Identifier: GPL-2.0 */
/*
 *  Copyright 2017 - Free Electrons
 *
 *  Authors:
 *	Boris Brezillon <boris.brezillon@free-electrons.com>
 *	Peter Pan <peterpandong@micron.com>
 */

#ifndef __LINUX_MTD_NAND_H
#define __LINUX_MTD_NAND_H

#include <stddef.h>
#include <stdlib.h>
#include <stdint.h>
#include <stdbool.h>
#include <errno.h>
#include <linux-types.h>

#define do_div(n,base) ({					\
	uint32_t __base = (base);				\
	uint32_t __rem;						\
	__rem = ((uint64_t)(n)) % __base;			\
	(n) = ((uint64_t)(n)) / __base;				\
	__rem;							\
 })

struct nand_device;

/**
 * struct nand_memory_organization - Memory organization structure
 * @bits_per_cell: number of bits per NAND cell
 * @pagesize: page size
 * @oobsize: OOB area size
 * @pages_per_eraseblock: number of pages per eraseblock
 * @eraseblocks_per_lun: number of eraseblocks per LUN (Logical Unit Number)
 * @max_bad_eraseblocks_per_lun: maximum number of eraseblocks per LUN
 * @planes_per_lun: number of planes per LUN
 * @luns_per_target: number of LUN per target (target is a synonym for die)
 * @ntargets: total number of targets exposed by the NAND device
 */
struct nand_memory_organization {
	unsigned int bits_per_cell;
	unsigned int pagesize;
	unsigned int oobsize;
	unsigned int pages_per_eraseblock;
	unsigned int eraseblocks_per_lun;
	unsigned int max_bad_eraseblocks_per_lun;
	unsigned int planes_per_lun;
	unsigned int luns_per_target;
	unsigned int ntargets;
};

#define NAND_MEMORG(bpc, ps, os, ppe, epl, mbb, ppl, lpt, nt)	\
	{							\
		.bits_per_cell = (bpc),				\
		.pagesize = (ps),				\
		.oobsize = (os),				\
		.pages_per_eraseblock = (ppe),			\
		.eraseblocks_per_lun = (epl),			\
		.max_bad_eraseblocks_per_lun = (mbb),		\
		.planes_per_lun = (ppl),			\
		.luns_per_target = (lpt),			\
		.ntargets = (nt),				\
	}

/**
 * struct nand_row_converter - Information needed to convert an absolute offset
 *			       into a row address
 * @lun_addr_shift: position of the LUN identifier in the row address
 * @eraseblock_addr_shift: position of the eraseblock identifier in the row
 *			   address
 */
struct nand_row_converter {
	unsigned int lun_addr_shift;
	unsigned int eraseblock_addr_shift;
};

/**
 * struct nand_pos - NAND position object
 * @target: the NAND target/die
 * @lun: the LUN identifier
 * @plane: the plane within the LUN
 * @eraseblock: the eraseblock within the LUN
 * @page: the page within the LUN
 *
 * These information are usually used by specific sub-layers to select the
 * appropriate target/die and generate a row address to pass to the device.
 */
struct nand_pos {
	unsigned int target;
	unsigned int lun;
	unsigned int plane;
	unsigned int eraseblock;
	unsigned int page;
};

/**
 * struct nand_page_io_req - NAND I/O request object
 * @pos: the position this I/O request is targeting
 * @dataoffs: the offset within the page
 * @datalen: number of data bytes to read from/write to this page
 * @databuf: buffer to store data in or get data from
 * @ooboffs: the OOB offset within the page
 * @ooblen: the number of OOB bytes to read from/write to this page
 * @oobbuf: buffer to store OOB data in or get OOB data from
 * @mode: one of the %MTD_OPS_XXX mode
 *
 * This object is used to pass per-page I/O requests to NAND sub-layers. This
 * way all useful information are already formatted in a useful way and
 * specific NAND layers can focus on translating these information into
 * specific commands/operations.
 */
struct nand_page_io_req {
	struct nand_pos pos;
	unsigned int dataoffs;
	unsigned int datalen;
	union {
		const void *out;
		void *in;
	} databuf;
	unsigned int ooboffs;
	unsigned int ooblen;
	union {
		const void *out;
		void *in;
	} oobbuf;
};

/**
 * struct nand_ecc_props - NAND ECC properties
 * @strength: ECC strength
 * @step_size: Number of bytes per step
 */
struct nand_ecc_props {
	unsigned int strength;
	unsigned int step_size;
};

#define NAND_ECCREQ(str, stp) { .strength = (str), .step_size = (stp) }

/**
 * struct nand_device - NAND device
 * @memorg: memory layout
 * @eccreq: ECC requirements
 * @rowconv: position to row address converter
 *
 * Generic NAND object. Specialized NAND layers (raw NAND, SPI NAND, OneNAND)
 * should declare their own NAND object embedding a nand_device struct (that's
 * how inheritance is done).
 * struct_nand_device->memorg and struct_nand_device->eccreq should be filled
 * at device detection time to reflect the NAND device
 */
struct nand_device {
	struct nand_memory_organization memorg;
	struct nand_ecc_props eccreq;
	struct nand_row_converter rowconv;
};

/**
 * struct nand_io_iter - NAND I/O iterator
 * @req: current I/O request
 * @oobbytes_per_page: maximum number of OOB bytes per page
 * @dataleft: remaining number of data bytes to read/write
 * @oobleft: remaining number of OOB bytes to read/write
 *
 * Can be used by specialized NAND layers to iterate over all pages covered
 * by an MTD I/O request, which should greatly simplifies the boiler-plate
 * code needed to read/write data from/to a NAND device.
 */
struct nand_io_iter {
	struct nand_page_io_req req;
	unsigned int oobbytes_per_page;
	unsigned int dataleft;
	unsigned int oobleft;
};

/*
 * nanddev_bits_per_cell() - Get the number of bits per cell
 * @nand: NAND device
 *
 * Return: the number of bits per cell.
 */
static inline unsigned int nanddev_bits_per_cell(const struct nand_device *nand)
{
	return nand->memorg.bits_per_cell;
}

/**
 * nanddev_page_size() - Get NAND page size
 * @nand: NAND device
 *
 * Return: the page size.
 */
static inline size_t nanddev_page_size(const struct nand_device *nand)
{
	return nand->memorg.pagesize;
}

/**
 * nanddev_per_page_oobsize() - Get NAND OOB size
 * @nand: NAND device
 *
 * Return: the OOB size.
 */
static inline unsigned int
nanddev_per_page_oobsize(const struct nand_device *nand)
{
	return nand->memorg.oobsize;
}

/**
 * nanddev_pages_per_eraseblock() - Get the number of pages per eraseblock
 * @nand: NAND device
 *
 * Return: the number of pages per eraseblock.
 */
static inline unsigned int
nanddev_pages_per_eraseblock(const struct nand_device *nand)
{
	return nand->memorg.pages_per_eraseblock;
}

/**
 * nanddev_pages_per_target() - Get the number of pages per target
 * @nand: NAND device
 *
 * Return: the number of pages per target.
 */
static inline unsigned int
nanddev_pages_per_target(const struct nand_device *nand)
{
	return nand->memorg.pages_per_eraseblock *
	       nand->memorg.eraseblocks_per_lun *
	       nand->memorg.luns_per_target;
}

/**
 * nanddev_per_page_oobsize() - Get NAND erase block size
 * @nand: NAND device
 *
 * Return: the eraseblock size.
 */
static inline size_t nanddev_eraseblock_size(const struct nand_device *nand)
{
	return nand->memorg.pagesize * nand->memorg.pages_per_eraseblock;
}

/**
 * nanddev_eraseblocks_per_lun() - Get the number of eraseblocks per LUN
 * @nand: NAND device
 *
 * Return: the number of eraseblocks per LUN.
 */
static inline unsigned int
nanddev_eraseblocks_per_lun(const struct nand_device *nand)
{
	return nand->memorg.eraseblocks_per_lun;
}

/**
 * nanddev_eraseblocks_per_target() - Get the number of eraseblocks per target
 * @nand: NAND device
 *
 * Return: the number of eraseblocks per target.
 */
static inline unsigned int
nanddev_eraseblocks_per_target(const struct nand_device *nand)
{
	return nand->memorg.eraseblocks_per_lun * nand->memorg.luns_per_target;
}

/**
 * nanddev_target_size() - Get the total size provided by a single target/die
 * @nand: NAND device
 *
 * Return: the total size exposed by a single target/die in bytes.
 */
static inline u64 nanddev_target_size(const struct nand_device *nand)
{
	return (u64)nand->memorg.luns_per_target *
	       nand->memorg.eraseblocks_per_lun *
	       nand->memorg.pages_per_eraseblock *
	       nand->memorg.pagesize;
}

/**
 * nanddev_ntarget() - Get the total of targets
 * @nand: NAND device
 *
 * Return: the number of targets/dies exposed by @nand.
 */
static inline unsigned int nanddev_ntargets(const struct nand_device *nand)
{
	return nand->memorg.ntargets;
}

/**
 * nanddev_neraseblocks() - Get the total number of eraseblocks
 * @nand: NAND device
 *
 * Return: the total number of eraseblocks exposed by @nand.
 */
static inline unsigned int nanddev_neraseblocks(const struct nand_device *nand)
{
	return nand->memorg.ntargets * nand->memorg.luns_per_target *
	       nand->memorg.eraseblocks_per_lun;
}

/**
 * nanddev_size() - Get NAND size
 * @nand: NAND device
 *
 * Return: the total size (in bytes) exposed by @nand.
 */
static inline u64 nanddev_size(const struct nand_device *nand)
{
	return nanddev_target_size(nand) * nanddev_ntargets(nand);
}

/**
 * nanddev_get_memorg() - Extract memory organization info from a NAND device
 * @nand: NAND device
 *
 * This can be used by the upper layer to fill the memorg info before calling
 * nanddev_init().
 *
 * Return: the memorg object embedded in the NAND device.
 */
static inline struct nand_memory_organization *
nanddev_get_memorg(struct nand_device *nand)
{
	return &nand->memorg;
}

/**
 * nanddev_offs_to_pos() - Convert an absolute NAND offset into a NAND position
 * @nand: NAND device
 * @offs: absolute NAND offset (usually passed by the MTD layer)
 * @pos: a NAND position object to fill in
 *
 * Converts @offs into a nand_pos representation.
 *
 * Return: the offset within the NAND page pointed by @pos.
 */
static inline unsigned int nanddev_offs_to_pos(struct nand_device *nand,
					       loff_t offs,
					       struct nand_pos *pos)
{
	unsigned int pageoffs;
	u64 tmp = offs;

	pageoffs = do_div(tmp, nand->memorg.pagesize);
	pos->page = do_div(tmp, nand->memorg.pages_per_eraseblock);
	pos->eraseblock = do_div(tmp, nand->memorg.eraseblocks_per_lun);
	pos->plane = pos->eraseblock % nand->memorg.planes_per_lun;
	pos->lun = do_div(tmp, nand->memorg.luns_per_target);
	pos->target = tmp;

	return pageoffs;
}

/**
 * nanddev_pos_cmp() - Compare two NAND positions
 * @a: First NAND position
 * @b: Second NAND position
 *
 * Compares two NAND positions.
 *
 * Return: -1 if @a < @b, 0 if @a == @b and 1 if @a > @b.
 */
static inline int nanddev_pos_cmp(const struct nand_pos *a,
				  const struct nand_pos *b)
{
	if (a->target != b->target)
		return a->target < b->target ? -1 : 1;

	if (a->lun != b->lun)
		return a->lun < b->lun ? -1 : 1;

	if (a->eraseblock != b->eraseblock)
		return a->eraseblock < b->eraseblock ? -1 : 1;

	if (a->page != b->page)
		return a->page < b->page ? -1 : 1;

	return 0;
}

/**
 * nanddev_pos_to_offs() - Convert a NAND position into an absolute offset
 * @nand: NAND device
 * @pos: the NAND position to convert
 *
 * Converts @pos NAND position into an absolute offset.
 *
 * Return: the absolute offset. Note that @pos points to the beginning of a
 *	   page, if one wants to point to a specific offset within this page
 *	   the returned offset has to be adjusted manually.
 */
static inline loff_t nanddev_pos_to_offs(struct nand_device *nand,
					 const struct nand_pos *pos)
{
	unsigned int npages;

	npages = pos->page +
		 ((pos->eraseblock +
		   (pos->lun +
		    (pos->target * nand->memorg.luns_per_target)) *
		   nand->memorg.eraseblocks_per_lun) *
		  nand->memorg.pages_per_eraseblock);

	return (loff_t)npages * nand->memorg.pagesize;
}

/**
 * nanddev_pos_to_row() - Extract a row address from a NAND position
 * @nand: NAND device
 * @pos: the position to convert
 *
 * Converts a NAND position into a row address that can then be passed to the
 * device.
 *
 * Return: the row address extracted from @pos.
 */
static inline unsigned int nanddev_pos_to_row(struct nand_device *nand,
					      const struct nand_pos *pos)
{
	return (pos->lun << nand->rowconv.lun_addr_shift) |
	       (pos->eraseblock << nand->rowconv.eraseblock_addr_shift) |
	       pos->page;
}

/**
 * nanddev_pos_next_target() - Move a position to the next target/die
 * @nand: NAND device
 * @pos: the position to update
 *
 * Updates @pos to point to the start of the next target/die. Useful when you
 * want to iterate over all targets/dies of a NAND device.
 */
static inline void nanddev_pos_next_target(struct nand_device *nand,
					   struct nand_pos *pos)
{
	pos->page = 0;
	pos->plane = 0;
	pos->eraseblock = 0;
	pos->lun = 0;
	pos->target++;
}

/**
 * nanddev_pos_next_lun() - Move a position to the next LUN
 * @nand: NAND device
 * @pos: the position to update
 *
 * Updates @pos to point to the start of the next LUN. Useful when you want to
 * iterate over all LUNs of a NAND device.
 */
static inline void nanddev_pos_next_lun(struct nand_device *nand,
					struct nand_pos *pos)
{
	if (pos->lun >= nand->memorg.luns_per_target - 1)
		return nanddev_pos_next_target(nand, pos);

	pos->lun++;
	pos->page = 0;
	pos->plane = 0;
	pos->eraseblock = 0;
}

/**
 * nanddev_pos_next_eraseblock() - Move a position to the next eraseblock
 * @nand: NAND device
 * @pos: the position to update
 *
 * Updates @pos to point to the start of the next eraseblock. Useful when you
 * want to iterate over all eraseblocks of a NAND device.
 */
static inline void nanddev_pos_next_eraseblock(struct nand_device *nand,
					       struct nand_pos *pos)
{
	if (pos->eraseblock >= nand->memorg.eraseblocks_per_lun - 1)
		return nanddev_pos_next_lun(nand, pos);

	pos->eraseblock++;
	pos->page = 0;
	pos->plane = pos->eraseblock % nand->memorg.planes_per_lun;
}

/**
 * nanddev_pos_next_page() - Move a position to the next page
 * @nand: NAND device
 * @pos: the position to update
 *
 * Updates @pos to point to the start of the next page. Useful when you want to
 * iterate over all pages of a NAND device.
 */
static inline void nanddev_pos_next_page(struct nand_device *nand,
					 struct nand_pos *pos)
{
	if (pos->page >= nand->memorg.pages_per_eraseblock - 1)
		return nanddev_pos_next_eraseblock(nand, pos);

	pos->page++;
}

static __always_inline int fls(int x)
{
    int r = 32;

    if (!x)
        return 0;
    if (!(x & 0xffff0000u)) {
        x <<= 16;
        r -= 16;
    }
    if (!(x & 0xff000000u)) {
        x <<= 8;
        r -= 8;
    }
    if (!(x & 0xf0000000u)) {
        x <<= 4;
        r -= 4;
    }
    if (!(x & 0xc0000000u)) {
        x <<= 2;
        r -= 2;
    }
    if (!(x & 0x80000000u)) {
        x <<= 1;
        r -= 1;
    }
    return r;
}

static inline int nanddev_init(struct nand_device *nand)
{
	struct nand_memory_organization *memorg = nanddev_get_memorg(nand);

	if (!nand)
		return -EINVAL;

	if (!memorg->bits_per_cell || !memorg->pagesize ||
	    !memorg->pages_per_eraseblock || !memorg->eraseblocks_per_lun ||
	    !memorg->planes_per_lun || !memorg->luns_per_target ||
	    !memorg->ntargets)
		return -EINVAL;

	nand->rowconv.eraseblock_addr_shift =
					fls(memorg->pages_per_eraseblock - 1);
	nand->rowconv.lun_addr_shift = fls(memorg->eraseblocks_per_lun - 1) +
				       nand->rowconv.eraseblock_addr_shift;
	return 0;
}
#endif /* __LINUX_MTD_NAND_H */
