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/*
* Copyright (c) 2017 MediaTek Inc.
* Author: Xiangsheng Hou <xiangsheng.hou@mediatek.com>
* Copyright (c) 2020-2022 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/kernel.h>
#include <linux/slab.h>
#include "mtk_bmt.h"
static bool
bbt_block_is_bad(u16 block)
{
u8 cur = bmtd.bbt_buf[block / 4];
return cur & (3 << ((block % 4) * 2));
}
static void
bbt_set_block_state(u16 block, bool bad)
{
u8 mask = (3 << ((block % 4) * 2));
if (bad)
bmtd.bbt_buf[block / 4] |= mask;
else
bmtd.bbt_buf[block / 4] &= ~mask;
bbt_nand_erase(bmtd.bmt_blk_idx);
write_bmt(bmtd.bmt_blk_idx, bmtd.bbt_buf);
}
static int
get_mapping_block_index_bbt(int block)
{
int start, end, ofs;
int bad_blocks = 0;
int i;
if (!mapping_block_in_range(block, &start, &end))
return block;
start >>= bmtd.blk_shift;
end >>= bmtd.blk_shift;
/* skip bad blocks within the mapping range */
ofs = block - start;
for (i = start; i < end; i++) {
if (bbt_block_is_bad(i))
bad_blocks++;
else if (ofs)
ofs--;
else
break;
}
if (i < end)
return i;
/* when overflowing, remap remaining blocks to bad ones */
for (i = end - 1; bad_blocks > 0; i--) {
if (!bbt_block_is_bad(i))
continue;
bad_blocks--;
if (bad_blocks <= ofs)
return i;
}
return block;
}
static bool remap_block_bbt(u16 block, u16 mapped_blk, int copy_len)
{
int start, end;
u16 new_blk;
if (!mapping_block_in_range(block, &start, &end))
return false;
bbt_set_block_state(mapped_blk, true);
new_blk = get_mapping_block_index_bbt(block);
bbt_nand_erase(new_blk);
if (copy_len > 0)
bbt_nand_copy(new_blk, mapped_blk, copy_len);
return true;
}
static void
unmap_block_bbt(u16 block)
{
bbt_set_block_state(block, false);
}
static int
mtk_bmt_read_bbt(void)
{
u8 oob_buf[8];
int i;
for (i = bmtd.total_blks - 1; i >= bmtd.total_blks - 5; i--) {
u32 page = i << (bmtd.blk_shift - bmtd.pg_shift);
if (bbt_nand_read(page, bmtd.bbt_buf, bmtd.pg_size,
oob_buf, sizeof(oob_buf))) {
pr_info("read_bbt: could not read block %d\n", i);
continue;
}
if (oob_buf[0] != 0xff) {
pr_info("read_bbt: bad block at %d\n", i);
continue;
}
if (memcmp(&oob_buf[1], "mtknand", 7) != 0) {
pr_info("read_bbt: signature mismatch in block %d\n", i);
print_hex_dump(KERN_INFO, "", DUMP_PREFIX_OFFSET, 16, 1, oob_buf, 8, 1);
continue;
}
pr_info("read_bbt: found bbt at block %d\n", i);
bmtd.bmt_blk_idx = i;
return 0;
}
return -EIO;
}
static int
mtk_bmt_init_bbt(struct device_node *np)
{
int buf_size = round_up(bmtd.total_blks >> 2, bmtd.blk_size);
int ret;
bmtd.bbt_buf = kmalloc(buf_size, GFP_KERNEL);
if (!bmtd.bbt_buf)
return -ENOMEM;
memset(bmtd.bbt_buf, 0xff, buf_size);
bmtd.mtd->size -= 4 * bmtd.mtd->erasesize;
ret = mtk_bmt_read_bbt();
if (ret)
return ret;
bmtd.bmt_pgs = buf_size / bmtd.pg_size;
return 0;
}
static int mtk_bmt_debug_bbt(void *data, u64 val)
{
char buf[5];
int i, k;
switch (val) {
case 0:
for (i = 0; i < bmtd.total_blks; i += 4) {
u8 cur = bmtd.bbt_buf[i / 4];
for (k = 0; k < 4; k++, cur >>= 2)
buf[k] = (cur & 3) ? 'B' : '.';
buf[4] = 0;
printk("[%06x] %s\n", i * bmtd.blk_size, buf);
}
break;
case 100:
#if 0
for (i = bmtd.bmt_blk_idx; i < bmtd.total_blks - 1; i++)
bbt_nand_erase(bmtd.bmt_blk_idx);
#endif
bmtd.bmt_blk_idx = bmtd.total_blks - 1;
bbt_nand_erase(bmtd.bmt_blk_idx);
write_bmt(bmtd.bmt_blk_idx, bmtd.bbt_buf);
break;
default:
break;
}
return 0;
}
const struct mtk_bmt_ops mtk_bmt_bbt_ops = {
.sig = "mtknand",
.sig_len = 7,
.init = mtk_bmt_init_bbt,
.remap_block = remap_block_bbt,
.unmap_block = unmap_block_bbt,
.get_mapping_block = get_mapping_block_index_bbt,
.debug = mtk_bmt_debug_bbt,
};
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