int fatfs_fat_set_cluster(struct fatfs *fs, UINT32 cluster, UINT32 next_cluster)
{
struct sector_buffer *pbuf;
UINT32 fat_sector_offset, position;
// Find which sector of FAT table to read
if (fs->fat_type == FAT_TYPE_16)
fat_sector_offset = cluster / 256;
else
fat_sector_offset = cluster / 128;
// Read FAT sector into buffer
pbuf = fatfs_fat_read_sector(fs, fs->fat_begin_lba+fat_sector_offset);
if (!pbuf)
return 0;
if (fs->fat_type == FAT_TYPE_16)
{
// Find 16 bit entry of current sector relating to cluster number
position = (cluster - (fat_sector_offset * 256)) * 2;
// Write Next Clusters value to Sector Buffer
FAT16_SET_16BIT_WORD(pbuf, (UINT16)position, ((UINT16)next_cluster));
}
else
{
// Find 32 bit entry of current sector relating to cluster number
position = (cluster - (fat_sector_offset * 128)) * 4;
// Write Next Clusters value to Sector Buffer
FAT32_SET_32BIT_WORD(pbuf, (UINT16)position, next_cluster);
}
return 1;
}
//-----------------------------------------------------------------------------
// fatfs_count_free_clusters:
//-----------------------------------------------------------------------------
UINT32 fatfs_count_free_clusters(struct fatfs *fs)
{
UINT32 i,j;
UINT32 count = 0;
struct sector_buffer *pbuf;
for (i = 0; i < fs->fat_sectors; i++)
{
// Read FAT sector into buffer
pbuf = fatfs_fat_read_sector(fs, fs->fat_begin_lba + i);
if (!pbuf)
break;
for (j = 0; j < FAT_SECTOR_SIZE; )
{
if (fs->fat_type == FAT_TYPE_16)
{
if (FAT16_GET_16BIT_WORD(pbuf, (UINT16)j) == 0)
count++;
j += 2;
}
else
{
if (FAT32_GET_32BIT_WORD(pbuf, (UINT16)j) == 0)
count++;
j += 4;
}
}
}
return count;
}
int fatfs_find_blank_cluster(struct fatfs *fs, UINT32 start_cluster, UINT32 *free_cluster)
{
UINT32 fat_sector_offset, position;
UINT32 nextcluster;
UINT32 current_cluster = start_cluster;
struct sector_buffer *pbuf;
do
{
// Find which sector of FAT table to read
if (fs->fat_type == FAT_TYPE_16)
fat_sector_offset = current_cluster / 256;
else
fat_sector_offset = current_cluster / 128;
if ( fat_sector_offset < fs->fat_sectors)
{
// Read FAT sector into buffer
pbuf = fatfs_fat_read_sector(fs, fs->fat_begin_lba+fat_sector_offset);
if (!pbuf)
return 0;
if (fs->fat_type == FAT_TYPE_16)
{
// Find 32 bit entry of current sector relating to cluster number
position = (current_cluster - (fat_sector_offset * 256)) * 2;
// Read Next Clusters value from Sector Buffer
nextcluster = FAT16_GET_16BIT_WORD(pbuf, (UINT16)position);
}
else
{
// Find 32 bit entry of current sector relating to cluster number
position = (current_cluster - (fat_sector_offset * 128)) * 4;
// Read Next Clusters value from Sector Buffer
nextcluster = FAT32_GET_32BIT_WORD(pbuf, (UINT16)position);
// Mask out MS 4 bits (its 28bit addressing)
nextcluster = nextcluster & 0x0FFFFFFF;
}
if (nextcluster !=0 )
current_cluster++;
}
else
// Otherwise, run out of FAT sectors to check...
return 0;
}
while (nextcluster != 0x0);
// Found blank entry
*free_cluster = current_cluster;
return 1;
}
//-----------------------------------------------------------------------------
// fatfs_find_next_cluster: Return cluster number of next cluster in chain by
// reading FAT table and traversing it. Return 0xffffffff for end of chain.
//-----------------------------------------------------------------------------
UINT32 fatfs_find_next_cluster(struct fatfs *fs, UINT32 current_cluster)
{
UINT32 fat_sector_offset, position;
UINT32 nextcluster;
struct sector_buffer *pbuf;
// Why is '..' labelled with cluster 0 when it should be 2 ??
if (current_cluster == 0)
current_cluster = 2;
// Find which sector of FAT table to read
if (fs->fat_type == FAT_TYPE_16)
fat_sector_offset = current_cluster / 256;
else
fat_sector_offset = current_cluster / 128;
// Read FAT sector into buffer
pbuf = fatfs_fat_read_sector(fs, fs->fat_begin_lba+fat_sector_offset);
if (!pbuf)
return (FAT32_LAST_CLUSTER);
if (fs->fat_type == FAT_TYPE_16)
{
// Find 32 bit entry of current sector relating to cluster number
position = (current_cluster - (fat_sector_offset * 256)) * 2;
// Read Next Clusters value from Sector Buffer
nextcluster = FAT16_GET_16BIT_WORD(pbuf, (UINT16)position);
// If end of chain found
if (nextcluster >= 0xFFF8 && nextcluster <= 0xFFFF)
return (FAT32_LAST_CLUSTER);
}
else
{
// Find 32 bit entry of current sector relating to cluster number
position = (current_cluster - (fat_sector_offset * 128)) * 4;
// Read Next Clusters value from Sector Buffer
nextcluster = FAT32_GET_32BIT_WORD(pbuf, (UINT16)position);
// Mask out MS 4 bits (its 28bit addressing)
nextcluster = nextcluster & 0x0FFFFFFF;
// If end of chain found
if (nextcluster >= 0x0FFFFFF8 && nextcluster <= 0x0FFFFFFF)
return (FAT32_LAST_CLUSTER);
}
// Else return next cluster
return (nextcluster);
}
//-----------------------------------------------------------------------------
// fatfs_set_fs_info_next_free_cluster: Write the next free cluster to the FSINFO table
//-----------------------------------------------------------------------------
void fatfs_set_fs_info_next_free_cluster(struct fatfs *fs, UINT32 newValue)
{
if (fs->fat_type == FAT_TYPE_16)
;
else
{
// Load sector to change it
struct sector_buffer *pbuf = fatfs_fat_read_sector(fs, fs->lba_begin+fs->fs_info_sector);
if (!pbuf)
return ;
// Change
FAT32_SET_32BIT_WORD(pbuf, 492, newValue);
fs->next_free_cluster = newValue;
}
}
//-----------------------------------------------------------------------------
// fatfs_set_fs_info_next_free_cluster: Write the next free cluster to the FSINFO table
//-----------------------------------------------------------------------------
void fatfs_set_fs_info_next_free_cluster(struct fatfs *fs, uint32 newValue)
{
if (fs->fat_type == FAT_TYPE_16)
;
else
{
// Load sector to change it
struct fat_buffer *pbuf = fatfs_fat_read_sector(fs, fs->lba_begin+fs->fs_info_sector);
if (!pbuf)
return ;
// Change
FAT32_SET_32BIT_WORD(pbuf, 492, newValue);
fs->next_free_cluster = newValue;
// Write back FSINFO sector to disk
if (fs->disk_io.write_media)
fs->disk_io.write_media(pbuf->address, pbuf->sector, 1);
// Invalidate cache entry
pbuf->address = FAT32_INVALID_CLUSTER;
pbuf->dirty = 0;
}
}
