void _FAT_partition_writeFSinfo(PARTITION * partition)
{
if(partition->filesysType != FS_FAT32)
return;
uint8_t *sectorBuffer = (uint8_t*) _FAT_mem_align(partition->bytesPerSector);
if (!sectorBuffer) return;
memset(sectorBuffer, 0, partition->bytesPerSector);
// Read first sector of disc
if (!_FAT_disc_readSectors (partition->disc, partition->fsInfoSector, 1, sectorBuffer)) {
_FAT_mem_free(sectorBuffer);
return;
}
if(memcmp(sectorBuffer+FSIB_SIG1, FS_INFO_SIG1, 4) || memcmp(sectorBuffer+FSIB_SIG2, FS_INFO_SIG2, 4)) {
_FAT_mem_free(sectorBuffer);
return;
}
u32_to_u8array(sectorBuffer, FSIB_numberOfFreeCluster, partition->fat.numberFreeCluster);
u32_to_u8array(sectorBuffer, FSIB_numberLastAllocCluster, partition->fat.numberLastAllocCluster);
// Write first sector of disc
_FAT_disc_writeSectors (partition->disc, partition->fsInfoSector, 1, sectorBuffer);
_FAT_mem_free(sectorBuffer);
}
void _FAT_partition_createFSinfo(PARTITION * partition)
{
if(partition->readOnly || partition->filesysType != FS_FAT32)
return;
uint8_t *sectorBuffer = (uint8_t*) _FAT_mem_align(partition->bytesPerSector);
if (!sectorBuffer) return;
memset(sectorBuffer, 0, partition->bytesPerSector);
int i;
for(i = 0; i < 4; ++i)
{
sectorBuffer[FSIB_SIG1+i] = FS_INFO_SIG1[i];
sectorBuffer[FSIB_SIG2+i] = FS_INFO_SIG2[i];
}
partition->fat.numberFreeCluster = _FAT_fat_freeClusterCount(partition);
u32_to_u8array(sectorBuffer, FSIB_numberOfFreeCluster, partition->fat.numberFreeCluster);
u32_to_u8array(sectorBuffer, FSIB_numberLastAllocCluster, partition->fat.numberLastAllocCluster);
sectorBuffer[FSIB_bootSig_55] = 0x55;
sectorBuffer[FSIB_bootSig_AA] = 0xAA;
_FAT_disc_writeSectors (partition->disc, partition->fsInfoSector, 1, sectorBuffer);
_FAT_mem_free(sectorBuffer);
}
/*
Flushes all dirty pages to disc, clearing the dirty flag.
*/
bool _FAT_cache_flush (CACHE* cache) {
unsigned int i;
for (i = 0; i < cache->numberOfPages; i++) {
if (cache->cacheEntries[i].dirty) {
if (!_FAT_disc_writeSectors (cache->disc, cache->cacheEntries[i].sector, cache->cacheEntries[i].count, cache->cacheEntries[i].cache)) {
return false;
}
}
cache->cacheEntries[i].dirty = false;
}
return true;
}
CACHE_ENTRY* _FAT_cache_getPage(CACHE *cache,sec_t sector)
{
unsigned int i;
CACHE_ENTRY* cacheEntries = cache->cacheEntries;
unsigned int numberOfPages = cache->numberOfPages;
unsigned int sectorsPerPage = cache->sectorsPerPage;
bool foundFree = false;
unsigned int oldUsed = 0;
unsigned int oldAccess = UINT_MAX;
for(i=0;i<numberOfPages;i++) {
if(sector>=cacheEntries[i].sector && sector<(cacheEntries[i].sector + cacheEntries[i].count)) {
cacheEntries[i].last_access = accessTime();
return &(cacheEntries[i]);
}
if(foundFree==false && (cacheEntries[i].sector==CACHE_FREE || cacheEntries[i].last_access<oldAccess)) {
if(cacheEntries[i].sector==CACHE_FREE) foundFree = true;
oldUsed = i;
oldAccess = cacheEntries[i].last_access;
}
}
if(foundFree==false && cacheEntries[oldUsed].dirty==true) {
if(!_FAT_disc_writeSectors(cache->disc,cacheEntries[oldUsed].sector,cacheEntries[oldUsed].count,cacheEntries[oldUsed].cache)) return NULL;
cacheEntries[oldUsed].dirty = false;
}
sector = (sector/sectorsPerPage)*sectorsPerPage; // align base sector to page size
sec_t next_page = sector + sectorsPerPage;
if(next_page > cache->endOfPartition) next_page = cache->endOfPartition;
if(!_FAT_disc_readSectors(cache->disc,sector,next_page-sector,cacheEntries[oldUsed].cache)) return NULL;
cacheEntries[oldUsed].sector = sector;
cacheEntries[oldUsed].count = next_page-sector;
cacheEntries[oldUsed].last_access = accessTime();
return &(cacheEntries[oldUsed]);
}
static void _FAT_updateFS_INFO(PARTITION * partition, uint8_t *sectorBuffer) {
partition->fat.numberFreeCluster = _FAT_fat_freeClusterCount(partition);
u32_to_u8array(sectorBuffer, FSIB_numberOfFreeCluster, partition->fat.numberFreeCluster);
u32_to_u8array(sectorBuffer, FSIB_numberLastAllocCluster, partition->fat.numberLastAllocCluster);
_FAT_disc_writeSectors (partition->disc, partition->fsInfoSector, 1, sectorBuffer);
}