--- /dev/null
+--- a/drivers/mtd/nand/Kconfig
++++ b/drivers/mtd/nand/Kconfig
+@@ -5,3 +5,7 @@ config MTD_NAND_CORE
+ source "drivers/mtd/nand/onenand/Kconfig"
+ source "drivers/mtd/nand/raw/Kconfig"
+ source "drivers/mtd/nand/spi/Kconfig"
++
++config MTD_NAND_MTK_BMT
++ bool "Support MediaTek NAND Bad-block Management Table"
++ default n
+--- a/drivers/mtd/nand/Makefile
++++ b/drivers/mtd/nand/Makefile
+@@ -2,6 +2,7 @@
+
+ nandcore-objs := core.o bbt.o
+ obj-$(CONFIG_MTD_NAND_CORE) += nandcore.o
++obj-$(CONFIG_MTD_NAND_MTK_BMT) += mtk_bmt.o
+
+ obj-y += onenand/
+ obj-y += raw/
+--- /dev/null
++++ b/drivers/mtd/nand/mtk_bmt.c
+@@ -0,0 +1,766 @@
++/*
++ * Copyright (c) 2017 MediaTek Inc.
++ * Author: Xiangsheng Hou <xiangsheng.hou@mediatek.com>
++ * Copyright (c) 2020 Felix Fietkau <nbd@nbd.name>
++ *
++ * 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/nand.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 0x2000U
++#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[BB_TABLE_MAX];
++ struct bbmt {
++ u16 block;
++#define NO_MAPPED 0
++#define NORMAL_MAPPED 1
++#define BMT_MAPPED 2
++ u16 mapped;
++ } bmt_tbl[BMT_TABLE_MAX];
++};
++
++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);
++ const struct nand_ops *nand_ops;
++
++ struct bbbt *bbt;
++
++ struct dentry *debugfs_dir;
++
++ 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 nand_device *nand = mtd_to_nanddev(bmtd.mtd);
++ loff_t addr = (loff_t)block << bmtd.blk_shift;
++ struct nand_pos pos;
++
++ nanddev_offs_to_pos(nand, addr, &pos);
++ return bmtd.nand_ops->erase(nand, &pos);
++}
++
++/* -------- Bad Blocks Management -------- */
++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) {
++ bbt->bmt_tbl[i].block = block;
++ bbt->bmt_tbl[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;
++ bbt->bmt_tbl[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(((struct bbbt *)nand_bbt_buf)->bmt_tbl);
++ 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 || bbt->bmt_tbl[n].mapped == NORMAL_MAPPED) {
++ pr_info("nand: FATAL ERR: no space to store BMT!\n");
++ return (u16)-1;
++ }
++
++ block = bbt->bmt_tbl[n].block;
++ BBT_LOG("n = 0x%x, block = 0x%x", n, block);
++ if (bbt_nand_erase(block)) {
++ bbt->bmt_tbl[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)) {
++ bbt->bmt_tbl[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 (bbt->bmt_tbl[i].block != 0 && bbt->bmt_tbl[i].mapped == NO_MAPPED) {
++ bbt->bmt_tbl[i].mapped = NORMAL_MAPPED;
++ return bbt->bmt_tbl[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.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.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_erase(struct nand_device *nand, const struct nand_pos *pos)
++{
++ struct nand_pos new_pos = *pos;
++ int retry_count = 0;
++ int ret;
++
++retry:
++ new_pos.eraseblock = get_mapping_block_index(pos->eraseblock);
++
++ ret = bmtd.nand_ops->erase(nand, &new_pos);
++ if (ret) {
++ update_bmt(pos->eraseblock);
++ if (retry_count++ < 10)
++ goto retry;
++ }
++
++ return ret;
++}
++
++static bool
++mtk_bmt_isbad(struct nand_device *nand, const struct nand_pos *pos)
++{
++ struct nand_pos new_pos = *pos;
++ int retry_count = 0;
++ bool ret;
++
++retry:
++ new_pos.eraseblock = get_mapping_block_index(pos->eraseblock);
++
++ ret = bmtd.nand_ops->isbad(nand, &new_pos);
++ if (ret) {
++ update_bmt(pos->eraseblock);
++ if (retry_count++ < 10)
++ goto retry;
++ }
++
++ return ret;
++}
++
++static int
++mtk_bmt_markbad(struct nand_device *nand, const struct nand_pos *pos)
++{
++ struct nand_pos new_pos = *pos;
++
++ new_pos.eraseblock = get_mapping_block_index(new_pos.eraseblock);
++ update_bmt(pos->eraseblock);
++
++ return bmtd.nand_ops->markbad(nand, &new_pos);
++}
++
++static void
++mtk_bmt_replace_ops(struct mtd_info *mtd)
++{
++ static const struct nand_ops mtk_bmt_nand_ops = {
++ .erase = mtk_bmt_erase,
++ .isbad = mtk_bmt_isbad,
++ .markbad = mtk_bmt_markbad,
++ };
++ struct nand_device *nand = mtd_to_nanddev(mtd);
++
++ bmtd.nand_ops = nand->ops;
++ bmtd._read_oob = mtd->_read_oob;
++ bmtd._write_oob = mtd->_write_oob;
++
++ mtd->_read_oob = mtk_bmt_read;
++ mtd->_write_oob = mtk_bmt_write;
++ nand->ops = &mtk_bmt_nand_ops;
++}
++
++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)
++{
++ struct nand_device *nand = mtd_to_nanddev(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->size = bmtd.total_blks << bmtd.blk_shift;
++ nand->ops = bmtd.nand_ops;
++
++ 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;
++
++ 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 = 8;
++
++ bmtd.mtd = mtd;
++ mtk_bmt_replace_ops(mtd);
++
++ 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), 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(bbt->bmt_tbl, BMT_TBL_DEF_VAL, sizeof(bbt->bmt_tbl));
++
++ 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 = bbt->bmt_tbl[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 <xiangsheng.hou@mediatek.com>, Felix Fietkau <nbd@nbd.name>");
++MODULE_DESCRIPTION("Bad Block mapping management v2 for MediaTek NAND Flash Driver");
++
+--- a/drivers/mtd/nand/spi/core.c
++++ b/drivers/mtd/nand/spi/core.c
+@@ -18,6 +18,7 @@
+ #include <linux/slab.h>
+ #include <linux/spi/spi.h>
+ #include <linux/spi/spi-mem.h>
++#include <linux/mtd/mtk_bmt.h>
+
+ static int spinand_read_reg_op(struct spinand_device *spinand, u8 reg, u8 *val)
+ {
+@@ -1099,6 +1100,8 @@ static int spinand_probe(struct spi_mem
+ if (ret)
+ return ret;
+
++ mtk_bmt_attach(mtd);
++
+ ret = mtd_device_register(mtd, NULL, 0);
+ if (ret)
+ goto err_spinand_cleanup;
+@@ -1124,6 +1127,7 @@ static int spinand_remove(struct spi_mem
+ if (ret)
+ return ret;
+
++ mtk_bmt_detach(mtd);
+ spinand_cleanup(spinand);
+
+ return 0;
+--- /dev/null
++++ b/include/linux/mtd/mtk_bmt.h
+@@ -0,0 +1,18 @@
++#ifndef __MTK_BMT_H
++#define __MTK_BMT_H
++
++#ifdef CONFIG_MTD_NAND_MTK_BMT
++int mtk_bmt_attach(struct mtd_info *mtd);
++void mtk_bmt_detach(struct mtd_info *mtd);
++#else
++static inline int mtk_bmt_attach(struct mtd_info *mtd)
++{
++ return 0;
++}
++
++static inline void mtk_bmt_detach(struct mtd_info *mtd)
++{
++}
++#endif
++
++#endif