target/linux/generic/files/fs/yaffs2/yaffs_bitmap.c

   1 /*
   2  * YAFFS: Yet Another Flash File System. A NAND-flash specific file system.
   3  *
   4  * Copyright (C) 2002-2011 Aleph One Ltd.
   5  *   for Toby Churchill Ltd and Brightstar Engineering
   6  *
   7  * Created by Charles Manning <charles@aleph1.co.uk>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License version 2 as
  11  * published by the Free Software Foundation.
  12  */
  13
  14 #include "yaffs_bitmap.h"
  15 #include "yaffs_trace.h"
  16 /*
  17  * Chunk bitmap manipulations
  18  */
  19
  20 static inline u8 *yaffs_block_bits(struct yaffs_dev *dev, int blk)
  21 {
  22         if (blk < dev->internal_start_block || blk > dev->internal_end_block) {
  23                 yaffs_trace(YAFFS_TRACE_ERROR,
  24                         "BlockBits block %d is not valid",
  25                         blk);
  26                 BUG();
  27         }
  28         return dev->chunk_bits +
  29             (dev->chunk_bit_stride * (blk - dev->internal_start_block));
  30 }
  31
  32 void yaffs_verify_chunk_bit_id(struct yaffs_dev *dev, int blk, int chunk)
  33 {
  34         if (blk < dev->internal_start_block || blk > dev->internal_end_block ||
  35             chunk < 0 || chunk >= dev->param.chunks_per_block) {
  36                 yaffs_trace(YAFFS_TRACE_ERROR,
  37                         "Chunk Id (%d:%d) invalid",
  38                         blk, chunk);
  39                 BUG();
  40         }
  41 }
  42
  43 void yaffs_clear_chunk_bits(struct yaffs_dev *dev, int blk)
  44 {
  45         u8 *blk_bits = yaffs_block_bits(dev, blk);
  46
  47         memset(blk_bits, 0, dev->chunk_bit_stride);
  48 }
  49
  50 void yaffs_clear_chunk_bit(struct yaffs_dev *dev, int blk, int chunk)
  51 {
  52         u8 *blk_bits = yaffs_block_bits(dev, blk);
  53
  54         yaffs_verify_chunk_bit_id(dev, blk, chunk);
  55         blk_bits[chunk / 8] &= ~(1 << (chunk & 7));
  56 }
  57
  58 void yaffs_set_chunk_bit(struct yaffs_dev *dev, int blk, int chunk)
  59 {
  60         u8 *blk_bits = yaffs_block_bits(dev, blk);
  61
  62         yaffs_verify_chunk_bit_id(dev, blk, chunk);
  63         blk_bits[chunk / 8] |= (1 << (chunk & 7));
  64 }
  65
  66 int yaffs_check_chunk_bit(struct yaffs_dev *dev, int blk, int chunk)
  67 {
  68         u8 *blk_bits = yaffs_block_bits(dev, blk);
  69
  70         yaffs_verify_chunk_bit_id(dev, blk, chunk);
  71         return (blk_bits[chunk / 8] & (1 << (chunk & 7))) ? 1 : 0;
  72 }
  73
  74 int yaffs_still_some_chunks(struct yaffs_dev *dev, int blk)
  75 {
  76         u8 *blk_bits = yaffs_block_bits(dev, blk);
  77         int i;
  78
  79         for (i = 0; i < dev->chunk_bit_stride; i++) {
  80                 if (*blk_bits)
  81                         return 1;
  82                 blk_bits++;
  83         }
  84         return 0;
  85 }
  86
  87 int yaffs_count_chunk_bits(struct yaffs_dev *dev, int blk)
  88 {
  89         u8 *blk_bits = yaffs_block_bits(dev, blk);
  90         int i;
  91         int n = 0;
  92
  93         for (i = 0; i < dev->chunk_bit_stride; i++, blk_bits++)
  94                 n += hweight8(*blk_bits);
  95
  96         return n;
  97 }