fs/yaffs2/yaffs_bitmap.c

   1 /*
   2  * YAFFS: Yet Another Flash File System. A NAND-flash specific file system.
   3  *
   4  * Copyright (C) 2002-2010 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                 YBUG();
  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                 YBUG();
  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
  56         blk_bits[chunk / 8] &= ~(1 << (chunk & 7));
  57 }
  58
  59 void yaffs_set_chunk_bit(struct yaffs_dev *dev, int blk, int chunk)
  60 {
  61         u8 *blk_bits = yaffs_block_bits(dev, blk);
  62
  63         yaffs_verify_chunk_bit_id(dev, blk, chunk);
  64
  65         blk_bits[chunk / 8] |= (1 << (chunk & 7));
  66 }
  67
  68 int yaffs_check_chunk_bit(struct yaffs_dev *dev, int blk, int chunk)
  69 {
  70         u8 *blk_bits = yaffs_block_bits(dev, blk);
  71         yaffs_verify_chunk_bit_id(dev, blk, chunk);
  72
  73         return (blk_bits[chunk / 8] & (1 << (chunk & 7))) ? 1 : 0;
  74 }
  75
  76 int yaffs_still_some_chunks(struct yaffs_dev *dev, int blk)
  77 {
  78         u8 *blk_bits = yaffs_block_bits(dev, blk);
  79         int i;
  80         for (i = 0; i < dev->chunk_bit_stride; i++) {
  81                 if (*blk_bits)
  82                         return 1;
  83                 blk_bits++;
  84         }
  85         return 0;
  86 }
  87
  88 int yaffs_count_chunk_bits(struct yaffs_dev *dev, int blk)
  89 {
  90         u8 *blk_bits = yaffs_block_bits(dev, blk);
  91         int i;
  92         int n = 0;
  93
  94         for (i = 0; i < dev->chunk_bit_stride; i++, blk_bits++)
  95                 n += hweight8(*blk_bits);
  96
  97         return n;
  98 }