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yaffs_bitmap.c
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yaffs_bitmap.c
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/*
* YAFFS: Yet Another Flash File System. A NAND-flash specific file system.
*
* Copyright (C) 2002-2018 Aleph One Ltd.
*
* Created by Charles Manning <[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.
*/
#include "yaffs_bitmap.h"
#include "yaffs_trace.h"
/*
* Chunk bitmap manipulations
*/
static inline u8 *yaffs_block_bits(struct yaffs_dev *dev, int blk)
{
if (blk < (int)dev->internal_start_block ||
blk > (int)dev->internal_end_block) {
yaffs_trace(YAFFS_TRACE_ERROR,
"BlockBits block %d is not valid",
blk);
BUG();
}
return dev->chunk_bits +
(dev->chunk_bit_stride * (blk - dev->internal_start_block));
}
void yaffs_verify_chunk_bit_id(struct yaffs_dev *dev, int blk, int chunk)
{
if (blk < (int)dev->internal_start_block ||
blk > (int)dev->internal_end_block ||
chunk < 0 || chunk >= (int)dev->param.chunks_per_block) {
yaffs_trace(YAFFS_TRACE_ERROR,
"Chunk Id (%d:%d) invalid",
blk, chunk);
BUG();
}
}
void yaffs_clear_chunk_bits(struct yaffs_dev *dev, int blk)
{
u8 *blk_bits = yaffs_block_bits(dev, blk);
memset(blk_bits, 0, dev->chunk_bit_stride);
}
void yaffs_clear_chunk_bit(struct yaffs_dev *dev, int blk, int chunk)
{
u8 *blk_bits = yaffs_block_bits(dev, blk);
yaffs_verify_chunk_bit_id(dev, blk, chunk);
blk_bits[chunk / 8] &= ~(1 << (chunk & 7));
}
void yaffs_set_chunk_bit(struct yaffs_dev *dev, int blk, int chunk)
{
u8 *blk_bits = yaffs_block_bits(dev, blk);
yaffs_verify_chunk_bit_id(dev, blk, chunk);
blk_bits[chunk / 8] |= (1 << (chunk & 7));
}
int yaffs_check_chunk_bit(struct yaffs_dev *dev, int blk, int chunk)
{
u8 *blk_bits = yaffs_block_bits(dev, blk);
yaffs_verify_chunk_bit_id(dev, blk, chunk);
return (blk_bits[chunk / 8] & (1 << (chunk & 7))) ? 1 : 0;
}
/*********************************************************************************************************
** 函数名称: yaffs_still_some_chunks
** 功能描述: 通过 chunk_bits 判断指定的块中是否还有数据存在
** 输 入: dev - yaffs 设备
** : blk - 判断的 nand_block 号
** 输 出: 1 - 还有数据
** : 0 - 没有数据
** 全局变量:
** 调用模块:
*********************************************************************************************************/
int yaffs_still_some_chunks(struct yaffs_dev *dev, int blk)
{
u8 *blk_bits = yaffs_block_bits(dev, blk);
int i;
for (i = 0; i < dev->chunk_bit_stride; i++) {
if (*blk_bits)
return 1;
blk_bits++;
}
return 0;
}
int yaffs_count_chunk_bits(struct yaffs_dev *dev, int blk)
{
u8 *blk_bits = yaffs_block_bits(dev, blk);
int i;
int n = 0;
for (i = 0; i < dev->chunk_bit_stride; i++, blk_bits++)
n += hweight8(*blk_bits);
return n;
}