openwrt/target/linux/generic/files/drivers/mtd/nand/mtk_bmt.c

/*
 * Copyright (c) 2017 MediaTek Inc.
 * Author: Xiangsheng Hou <[email protected]>
 * Copyright (c) 2020 Felix Fietkau <[email protected]>
 *
 * 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.
 *
 * 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.
 */

#include <linux/slab.h>
#include <linux/gfp.h>
#include <linux/kernel.h>
#include <linux/of.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/partitions.h>
#include <linux/mtd/mtk_bmt.h>
#include <linux/module.h>
#include <linux/debugfs.h>

#define MAIN_SIGNATURE_OFFSET   0
#define OOB_SIGNATURE_OFFSET    1
#define BBPOOL_RATIO		2

#define BBT_LOG(fmt, ...) pr_debug("[BBT][%s|%d] "fmt"\n", __func__, __LINE__, ##__VA_ARGS__)

/* Maximum 8k blocks */
#define BB_TABLE_MAX	bmtd.table_size
#define BMT_TABLE_MAX	(BB_TABLE_MAX * BBPOOL_RATIO / 100)
#define BMT_TBL_DEF_VAL	0x0

/*
 * Burner Bad Block Table
 * --------- Only support SLC Nand Chips!!!!!!!!!!! ----------
 */

struct bbbt {
	char signature[3];
	/* This version is used to distinguish the legacy and new algorithm */
#define BBMT_VERSION		2
	unsigned char version;
	/* Below 2 tables will be written in SLC */
	u16 bb_tbl[];
};

struct bbmt {
	u16 block;
#define NO_MAPPED		0
#define NORMAL_MAPPED	1
#define BMT_MAPPED		2
	u16 mapped;
};

static struct bmt_desc {
	struct mtd_info *mtd;

	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);
	int (*_erase) (struct mtd_info *mtd, struct erase_info *instr);
	int (*_block_isbad) (struct mtd_info *mtd, loff_t ofs);
	int (*_block_markbad) (struct mtd_info *mtd, loff_t ofs);

	struct bbbt *bbt;

	struct dentry *debugfs_dir;

	u32 table_size;
	u32 pg_size;
	u32 blk_size;
	u16 pg_shift;
	u16 blk_shift;
	/* bbt logical address */
	u16 pool_lba;
	/* bbt physical address */
	u16 pool_pba;
	/* Maximum count of bad blocks that the vendor guaranteed */
	u16 bb_max;
	/* Total blocks of the Nand Chip */
	u16 total_blks;
	/* The block(n) BMT is located at (bmt_tbl[n]) */
	u16 bmt_blk_idx;
	/* How many pages needs to store 'struct bbbt' */
	u32 bmt_pgs;

	/* to compensate for driver level remapping */
	u8 oob_offset;
} bmtd = {0};

static unsigned char *nand_bbt_buf;
static unsigned char *nand_data_buf;

/* -------- Unit conversions -------- */
static inline u32 blk_pg(u16 block)
{
	return (u32)(block << (bmtd.blk_shift - bmtd.pg_shift));
}

/* -------- Nand operations wrapper -------- */
static inline int
bbt_nand_read(u32 page, unsigned char *dat, int dat_len,
	      unsigned char *fdm, int fdm_len)
{
	struct mtd_oob_ops ops = {
		.mode = MTD_OPS_PLACE_OOB,
		.ooboffs = bmtd.oob_offset,
		.oobbuf = fdm,
		.ooblen = fdm_len,
		.datbuf = dat,
		.len = dat_len,
	};

	return bmtd._read_oob(bmtd.mtd, page << bmtd.pg_shift, &ops);
}

static inline int bbt_nand_erase(u16 block)
{
	struct mtd_info *mtd = bmtd.mtd;
	struct erase_info instr = {
		.addr = (loff_t)block << bmtd.blk_shift,
		.len = bmtd.blk_size,
	};

	return bmtd._erase(mtd, &instr);
}

/* -------- Bad Blocks Management -------- */
static inline struct bbmt *bmt_tbl(struct bbbt *bbbt)
{
	return (struct bbmt *)&bbbt->bb_tbl[bmtd.table_size];
}

static int
read_bmt(u16 block, unsigned char *dat, unsigned char *fdm, int fdm_len)
{
	u32 len = bmtd.bmt_pgs << bmtd.pg_shift;

	return bbt_nand_read(blk_pg(block), dat, len, fdm, fdm_len);
}

static int write_bmt(u16 block, unsigned char *dat)
{
	struct mtd_oob_ops ops = {
		.mode = MTD_OPS_PLACE_OOB,
		.ooboffs = OOB_SIGNATURE_OFFSET + bmtd.oob_offset,
		.oobbuf = "bmt",
		.ooblen = 3,
		.datbuf = dat,
		.len = bmtd.bmt_pgs << bmtd.pg_shift,
	};
	loff_t addr = (loff_t)block << bmtd.blk_shift;

	return bmtd._write_oob(bmtd.mtd, addr, &ops);
}

static u16 find_valid_block(u16 block)
{
	u8 fdm[4];
	int ret;
	int loop = 0;

retry:
	if (block >= bmtd.total_blks)
		return 0;

	ret = bbt_nand_read(blk_pg(block), nand_data_buf, bmtd.pg_size,
			    fdm, sizeof(fdm));
	/* Read the 1st byte of FDM to judge whether it's a bad
	 * or not
	 */
	if (ret || fdm[0] != 0xff) {
		pr_info("nand: found bad block 0x%x\n", block);
		if (loop >= bmtd.bb_max) {
			pr_info("nand: FATAL ERR: too many bad blocks!!\n");
			return 0;
		}

		loop++;
		block++;
		goto retry;
	}

	return block;
}

/* Find out all bad blocks, and fill in the mapping table */
static int scan_bad_blocks(struct bbbt *bbt)
{
	int i;
	u16 block = 0;

	/* First time download, the block0 MUST NOT be a bad block,
	 * this is guaranteed by vendor
	 */
	bbt->bb_tbl[0] = 0;

	/*
	 * Construct the mapping table of Normal data area(non-PMT/BMTPOOL)
	 * G - Good block; B - Bad block
	 *			---------------------------
	 * physical |G|G|B|G|B|B|G|G|G|G|B|G|B|
	 *			---------------------------
	 * What bb_tbl[i] looks like:
	 *   physical block(i):
	 *			 0 1 2 3 4 5 6 7 8 9 a b c
	 *   mapped block(bb_tbl[i]):
	 *			 0 1 3 6 7 8 9 b ......
	 * ATTENTION:
	 *		If new bad block ocurred(n), search bmt_tbl to find
	 *		a available block(x), and fill in the bb_tbl[n] = x;
	 */
	for (i = 1; i < bmtd.pool_lba; i++) {
		bbt->bb_tbl[i] = find_valid_block(bbt->bb_tbl[i - 1] + 1);
		BBT_LOG("bb_tbl[0x%x] = 0x%x", i, bbt->bb_tbl[i]);
		if (bbt->bb_tbl[i] == 0)
			return -1;
	}

	/* Physical Block start Address of BMT pool */
	bmtd.pool_pba = bbt->bb_tbl[i - 1] + 1;
	if (bmtd.pool_pba >= bmtd.total_blks - 2) {
		pr_info("nand: FATAL ERR: Too many bad blocks!!\n");
		return -1;
	}

	BBT_LOG("pool_pba=0x%x", bmtd.pool_pba);
	i = 0;
	block = bmtd.pool_pba;
	/*
	 * The bmt table is used for runtime bad block mapping
	 * G - Good block; B - Bad block
	 *			---------------------------
	 * physical |G|G|B|G|B|B|G|G|G|G|B|G|B|
	 *			---------------------------
	 *   block:	 0 1 2 3 4 5 6 7 8 9 a b c
	 * What bmt_tbl[i] looks like in initial state:
	 *   i:
	 *			 0 1 2 3 4 5 6 7
	 *   bmt_tbl[i].block:
	 *			 0 1 3 6 7 8 9 b
	 *   bmt_tbl[i].mapped:
	 *			 N N N N N N N B
	 *		N - Not mapped(Available)
	 *		M - Mapped
	 *		B - BMT
	 * ATTENTION:
	 *		BMT always in the last valid block in pool
	 */
	while ((block = find_valid_block(block)) != 0) {
		bmt_tbl(bbt)[i].block = block;
		bmt_tbl(bbt)[i].mapped = NO_MAPPED;
		BBT_LOG("bmt_tbl[%d].block = 0x%x", i, block);
		block++;
		i++;
	}

	/* i - How many available blocks in pool, which is the length of bmt_tbl[]
	 * bmtd.bmt_blk_idx - bmt_tbl[bmtd.bmt_blk_idx].block => the BMT block
	 */
	bmtd.bmt_blk_idx = i - 1;
	bmt_tbl(bbt)[bmtd.bmt_blk_idx].mapped = BMT_MAPPED;

	if (i < 1) {
		pr_info("nand: FATAL ERR: no space to store BMT!!\n");
		return -1;
	}

	pr_info("[BBT] %d available blocks in BMT pool\n", i);

	return 0;
}

static bool is_valid_bmt(unsigned char *buf, unsigned char *fdm)
{
	struct bbbt *bbt = (struct bbbt *)buf;
	u8 *sig = (u8*)bbt->signature + MAIN_SIGNATURE_OFFSET;


	if (memcmp(bbt->signature + MAIN_SIGNATURE_OFFSET, "BMT", 3) == 0 &&
		memcmp(fdm + OOB_SIGNATURE_OFFSET, "bmt", 3) == 0) {
		if (bbt->version == BBMT_VERSION)
			return true;
	}
	BBT_LOG("[BBT] BMT Version not match,upgrage preloader and uboot please! sig=%02x%02x%02x, fdm=%02x%02x%02x",
		sig[0], sig[1], sig[2],
		fdm[1], fdm[2], fdm[3]);
	return false;
}

static u16 get_bmt_index(struct bbmt *bmt)
{
	int i = 0;

	while (bmt[i].block != BMT_TBL_DEF_VAL) {
		if (bmt[i].mapped == BMT_MAPPED)
			return i;
		i++;
	}
	return 0;
}

static struct bbbt *scan_bmt(u16 block)
{
	u8 fdm[4];

	if (block < bmtd.pool_lba)
		return NULL;

	if (read_bmt(block, nand_bbt_buf, fdm, sizeof(fdm)))
		return scan_bmt(block - 1);

	if (is_valid_bmt(nand_bbt_buf, fdm)) {
		bmtd.bmt_blk_idx = get_bmt_index(bmt_tbl((struct bbbt *)nand_bbt_buf));
		if (bmtd.bmt_blk_idx == 0) {
			pr_info("[BBT] FATAL ERR: bmt block index is wrong!\n");
			return NULL;
		}
		pr_info("[BBT] BMT.v2 is found at 0x%x\n", block);
		return (struct bbbt *)nand_bbt_buf;
	} else
		return scan_bmt(block - 1);
}

/* Write the Burner Bad Block Table to Nand Flash
 * n - write BMT to bmt_tbl[n]
 */
static u16 upload_bmt(struct bbbt *bbt, int n)
{
	u16 block;

retry:
	if (n < 0 || bmt_tbl(bbt)[n].mapped == NORMAL_MAPPED) {
		pr_info("nand: FATAL ERR: no space to store BMT!\n");
		return (u16)-1;
	}

	block = bmt_tbl(bbt)[n].block;
	BBT_LOG("n = 0x%x, block = 0x%x", n, block);
	if (bbt_nand_erase(block)) {
		bmt_tbl(bbt)[n].block = 0;
		/* erase failed, try the previous block: bmt_tbl[n - 1].block */
		n--;
		goto retry;
	}

	/* The signature offset is fixed set to 0,
	 * oob signature offset is fixed set to 1
	 */
	memcpy(bbt->signature + MAIN_SIGNATURE_OFFSET, "BMT", 3);
	bbt->version = BBMT_VERSION;

	if (write_bmt(block, (unsigned char *)bbt)) {
		bmt_tbl(bbt)[n].block = 0;

		/* write failed, try the previous block in bmt_tbl[n - 1] */
		n--;
		goto retry;
	}

	/* Return the current index(n) of BMT pool (bmt_tbl[n]) */
	return n;
}

static u16 find_valid_block_in_pool(struct bbbt *bbt)
{
	int i;

	if (bmtd.bmt_blk_idx == 0)
		goto error;

	for (i = 0; i < bmtd.bmt_blk_idx; i++) {
		if (bmt_tbl(bbt)[i].block != 0 && bmt_tbl(bbt)[i].mapped == NO_MAPPED) {
			bmt_tbl(bbt)[i].mapped = NORMAL_MAPPED;
			return bmt_tbl(bbt)[i].block;
		}
	}

error:
	pr_info("nand: FATAL ERR: BMT pool is run out!\n");
	return 0;
}

/* We met a bad block, mark it as bad and map it to a valid block in pool,
 * if it's a write failure, we need to write the data to mapped block
 */
static bool update_bmt(u16 block)
{
	u16 mapped_blk;
	struct bbbt *bbt;

	bbt = bmtd.bbt;
	mapped_blk = find_valid_block_in_pool(bbt);
	if (mapped_blk == 0)
		return false;

	/* Map new bad block to available block in pool */
	bbt->bb_tbl[block] = mapped_blk;
	bmtd.bmt_blk_idx = upload_bmt(bbt, bmtd.bmt_blk_idx);

	return true;
}

u16 get_mapping_block_index(int block)
{
	int mapping_block;

	if (block < bmtd.pool_lba)
		mapping_block = bmtd.bbt->bb_tbl[block];
	else
		mapping_block = block;
	BBT_LOG("0x%x mapped to 0x%x", block, mapping_block);

	return mapping_block;
}

static int
mtk_bmt_read(struct mtd_info *mtd, loff_t from,
	     struct mtd_oob_ops *ops)
{
	struct mtd_oob_ops cur_ops = *ops;
	int retry_count = 0;
	loff_t cur_from;
	int ret;

	ops->retlen = 0;
	ops->oobretlen = 0;

	while (ops->retlen < ops->len || ops->oobretlen < ops->ooblen) {
		u32 offset = from & (bmtd.blk_size - 1);
		u32 block = from >> bmtd.blk_shift;
		u32 cur_block;

		cur_block = get_mapping_block_index(block);
		cur_from = ((loff_t)cur_block << bmtd.blk_shift) + offset;

		cur_ops.oobretlen = 0;
		cur_ops.retlen = 0;
		cur_ops.len = min_t(u32, mtd->erasesize - offset,
					 ops->len - ops->retlen);
		ret = bmtd._read_oob(mtd, cur_from, &cur_ops);
		if (ret < 0) {
			update_bmt(block);
			if (retry_count++ < 10)
				continue;

			return ret;
		}

		ops->retlen += cur_ops.retlen;
		ops->oobretlen += cur_ops.oobretlen;

		cur_ops.ooboffs = 0;
		cur_ops.datbuf += cur_ops.retlen;
		cur_ops.oobbuf += cur_ops.oobretlen;
		cur_ops.ooblen -= cur_ops.oobretlen;

		if (!cur_ops.len)
			cur_ops.len = mtd->erasesize - offset;

		from += cur_ops.len;
		retry_count = 0;
	}

	return 0;
}

static int
mtk_bmt_write(struct mtd_info *mtd, loff_t to,
	      struct mtd_oob_ops *ops)
{
	struct mtd_oob_ops cur_ops = *ops;
	int retry_count = 0;
	loff_t cur_to;
	int ret;

	ops->retlen = 0;
	ops->oobretlen = 0;

	while (ops->retlen < ops->len || ops->oobretlen < ops->ooblen) {
		u32 offset = to & (bmtd.blk_size - 1);
		u32 block = to >> bmtd.blk_shift;
		u32 cur_block;

		cur_block = get_mapping_block_index(block);
		cur_to = ((loff_t)cur_block << bmtd.blk_shift) + offset;

		cur_ops.oobretlen = 0;
		cur_ops.retlen = 0;
		cur_ops.len = min_t(u32, bmtd.blk_size - offset,
					 ops->len - ops->retlen);
		ret = bmtd._write_oob(mtd, cur_to, &cur_ops);
		if (ret < 0) {
			update_bmt(block);
			if (retry_count++ < 10)
				continue;

			return ret;
		}

		ops->retlen += cur_ops.retlen;
		ops->oobretlen += cur_ops.oobretlen;

		cur_ops.ooboffs = 0;
		cur_ops.datbuf += cur_ops.retlen;
		cur_ops.oobbuf += cur_ops.oobretlen;
		cur_ops.ooblen -= cur_ops.oobretlen;

		if (!cur_ops.len)
			cur_ops.len = mtd->erasesize - offset;

		to += cur_ops.len;
		retry_count = 0;
	}

	return 0;
}

static int
mtk_bmt_mtd_erase(struct mtd_info *mtd, struct erase_info *instr)
{
	struct erase_info mapped_instr = {
		.len = bmtd.blk_size,
	};
	int retry_count = 0;
	u64 start_addr, end_addr;
	int ret;
	u16 orig_block, block;

	start_addr = instr->addr & (~mtd->erasesize_mask);
	end_addr = instr->addr + instr->len;

	while (start_addr < end_addr) {
		orig_block = start_addr >> bmtd.blk_shift;
		block = get_mapping_block_index(orig_block);
		mapped_instr.addr = (loff_t)block << bmtd.blk_shift;
		ret = bmtd._erase(mtd, &mapped_instr);
		if (ret) {
			update_bmt(orig_block);
			if (retry_count++ < 10)
				continue;
			instr->fail_addr = start_addr;
			break;
		}
		start_addr += mtd->erasesize;
		retry_count = 0;
	}

	return ret;
}
static int
mtk_bmt_block_isbad(struct mtd_info *mtd, loff_t ofs)
{
	int retry_count = 0;
	u16 orig_block = ofs >> bmtd.blk_shift;
	u16 block;
	int ret;

retry:
	block = get_mapping_block_index(orig_block);
	ret = bmtd._block_isbad(mtd, (loff_t)block << bmtd.blk_shift);
	if (ret) {
		update_bmt(orig_block);
		if (retry_count++ < 10)
			goto retry;
	}
	return ret;
}

static int
mtk_bmt_block_markbad(struct mtd_info *mtd, loff_t ofs)
{
	u16 orig_block = ofs >> bmtd.blk_shift;
	u16 block = get_mapping_block_index(orig_block);
	update_bmt(orig_block);
	return bmtd._block_markbad(mtd, (loff_t)block << bmtd.blk_shift);
}

static void
mtk_bmt_replace_ops(struct mtd_info *mtd)
{
	bmtd._read_oob = mtd->_read_oob;
	bmtd._write_oob = mtd->_write_oob;
	bmtd._erase = mtd->_erase;
	bmtd._block_isbad = mtd->_block_isbad;
	bmtd._block_markbad = mtd->_block_markbad;

	mtd->_read_oob = mtk_bmt_read;
	mtd->_write_oob = mtk_bmt_write;
	mtd->_erase = mtk_bmt_mtd_erase;
	mtd->_block_isbad = mtk_bmt_block_isbad;
	mtd->_block_markbad = mtk_bmt_block_markbad;
}

static int mtk_bmt_debug_mark_good(void *data, u64 val)
{
	u32 block = val >> bmtd.blk_shift;

	bmtd.bbt->bb_tbl[block] = block;
	bmtd.bmt_blk_idx = upload_bmt(bmtd.bbt, bmtd.bmt_blk_idx);

	return 0;
}

static int mtk_bmt_debug_mark_bad(void *data, u64 val)
{
	u32 block = val >> bmtd.blk_shift;

	update_bmt(block);

	return 0;
}

DEFINE_DEBUGFS_ATTRIBUTE(fops_mark_good, NULL, mtk_bmt_debug_mark_good, "%llu\n");
DEFINE_DEBUGFS_ATTRIBUTE(fops_mark_bad, NULL, mtk_bmt_debug_mark_bad, "%llu\n");

static void
mtk_bmt_add_debugfs(void)
{
	struct dentry *dir;

	dir = bmtd.debugfs_dir = debugfs_create_dir("mtk-bmt", NULL);
	if (!dir)
		return;

	debugfs_create_file_unsafe("mark_good", S_IWUSR, dir, NULL, &fops_mark_good);
	debugfs_create_file_unsafe("mark_bad", S_IWUSR, dir, NULL, &fops_mark_bad);
}

void mtk_bmt_detach(struct mtd_info *mtd)
{
	if (bmtd.mtd != mtd)
		return;

	if (bmtd.debugfs_dir)
		debugfs_remove_recursive(bmtd.debugfs_dir);
	bmtd.debugfs_dir = NULL;

	kfree(nand_bbt_buf);
	kfree(nand_data_buf);

	mtd->_read_oob = bmtd._read_oob;
	mtd->_write_oob = bmtd._write_oob;
	mtd->_erase = bmtd._erase;
	mtd->_block_isbad = bmtd._block_isbad;
	mtd->_block_markbad = bmtd._block_markbad;
	mtd->size = bmtd.total_blks << bmtd.blk_shift;

	memset(&bmtd, 0, sizeof(bmtd));
}

/* total_blocks - The total count of blocks that the Nand Chip has */
int mtk_bmt_attach(struct mtd_info *mtd)
{
	struct device_node *np;
	struct bbbt *bbt;
	u32 bufsz;
	u32 block;
	u16 total_blocks, pmt_block;
	int ret = 0;
	u32 bmt_pool_size, bmt_table_size;

	if (bmtd.mtd)
		return -ENOSPC;

	np = mtd_get_of_node(mtd);
	if (!np)
		return 0;

	if (!of_property_read_bool(np, "mediatek,bmt-v2"))
		return 0;

	if (of_property_read_u32(np, "mediatek,bmt-pool-size",
				 &bmt_pool_size) != 0)
		bmt_pool_size = 80;

	if (of_property_read_u8(np, "mediatek,bmt-oob-offset",
				 &bmtd.oob_offset) != 0)
		bmtd.oob_offset = 0;

	if (of_property_read_u32(np, "mediatek,bmt-table-size",
				 &bmt_table_size) != 0)
		bmt_table_size = 0x2000U;

	bmtd.mtd = mtd;
	mtk_bmt_replace_ops(mtd);

	bmtd.table_size = bmt_table_size;
	bmtd.blk_size = mtd->erasesize;
	bmtd.blk_shift = ffs(bmtd.blk_size) - 1;
	bmtd.pg_size = mtd->writesize;
	bmtd.pg_shift = ffs(bmtd.pg_size) - 1;
	total_blocks = mtd->size >> bmtd.blk_shift;
	pmt_block = total_blocks - bmt_pool_size - 2;

	mtd->size = pmt_block << bmtd.blk_shift;

	/*
	 *  ---------------------------------------
	 * | PMT(2blks) | BMT POOL(totalblks * 2%) |
	 *  ---------------------------------------
	 * ^            ^
	 * |            |
	 * pmt_block	pmt_block + 2blocks(pool_lba)
	 *
	 * ATTETION!!!!!!
	 *     The blocks ahead of the boundary block are stored in bb_tbl
	 *     and blocks behind are stored in bmt_tbl
	 */

	bmtd.pool_lba = (u16)(pmt_block + 2);
	bmtd.total_blks = total_blocks;
	bmtd.bb_max = bmtd.total_blks * BBPOOL_RATIO / 100;

	/* 3 buffers we need */
	bufsz = round_up(sizeof(struct bbbt) +
			 bmt_table_size * sizeof(struct bbmt), bmtd.pg_size);
	bmtd.bmt_pgs = bufsz >> bmtd.pg_shift;

	nand_bbt_buf = kzalloc(bufsz, GFP_KERNEL);
	nand_data_buf = kzalloc(bmtd.pg_size, GFP_KERNEL);

	if (!nand_bbt_buf || !nand_data_buf) {
		pr_info("nand: FATAL ERR: allocate buffer failed!\n");
		ret = -1;
		goto error;
	}

	memset(nand_bbt_buf, 0xff, bufsz);
	memset(nand_data_buf, 0xff, bmtd.pg_size);

	BBT_LOG("bbtbuf=0x%p(0x%x) dat=0x%p(0x%x)",
			nand_bbt_buf, bufsz, nand_data_buf, bmtd.pg_size);
	BBT_LOG("pool_lba=0x%x total_blks=0x%x bb_max=0x%x",
			bmtd.pool_lba, bmtd.total_blks, bmtd.bb_max);

	/* Scanning start from the first page of the last block
	 * of whole flash
	 */
	bbt = scan_bmt(bmtd.total_blks - 1);
	if (!bbt) {
		/* BMT not found */
		if (bmtd.total_blks > BB_TABLE_MAX + BMT_TABLE_MAX) {
			pr_info("nand: FATAL: Too many blocks, can not support!\n");
			ret = -1;
			goto error;
		}

		bbt = (struct bbbt *)nand_bbt_buf;
		memset(bmt_tbl(bbt), BMT_TBL_DEF_VAL, bmtd.table_size * sizeof(struct bbmt));

		if (scan_bad_blocks(bbt)) {
			ret = -1;
			goto error;
		}

		/* BMT always in the last valid block in pool */
		bmtd.bmt_blk_idx = upload_bmt(bbt, bmtd.bmt_blk_idx);
		block = bmt_tbl(bbt)[bmtd.bmt_blk_idx].block;
		pr_notice("[BBT] BMT.v2 is written into PBA:0x%x\n", block);

		if (bmtd.bmt_blk_idx == 0)
			pr_info("nand: Warning: no available block in BMT pool!\n");
		else if (bmtd.bmt_blk_idx == (u16)-1) {
			ret = -1;
			goto error;
		}
	}
	mtk_bmt_add_debugfs();

	bmtd.bbt = bbt;
	return 0;

error:
	mtk_bmt_detach(mtd);
	return ret;
}


MODULE_LICENSE("GPL");
MODULE_AUTHOR("Xiangsheng Hou <[email protected]>, Felix Fietkau <[email protected]>");
MODULE_DESCRIPTION("Bad Block mapping management v2 for MediaTek NAND Flash Driver");