//------------------------------------------------------------------------------
// Store a FAT entry
uint8_t SdVolume::fatPut(uint32_t cluster, uint32_t value) {
// error if reserved cluster
if (cluster < 2)
return false;
// error if not in FAT
if (cluster > (clusterCount_ + 1))
return false;
// calculate block address for entry
uint32_t lba = fatStartBlock_;
lba += fatType_ == 16 ? cluster >> 8 : cluster >> 7;
if (lba != cacheBlockNumber_)
{
if (!cacheRawBlock(lba, CACHE_FOR_READ)) return false;
}
// store entry
if (fatType_ == 16)
{
cacheBuffer_.fat16[cluster & 0XFF] = value;
}
else
{
cacheBuffer_.fat32[cluster & 0X7F] = value;
}
cacheSetDirty();
// mirror second FAT
if (fatCount_ > 1)
cacheMirrorBlock_ = lba + blocksPerFat_;
return true;
}
//------------------------------------------------------------------------------
// Fetch a FAT entry
uint8_t SdVolume::fatGet(uint32_t cluster, uint32_t* value) const {
if (cluster > (clusterCount_ + 1)) return false;
uint32_t lba = fatStartBlock_;
lba += fatType_ == 16 ? cluster >> 8 : cluster >> 7;
if (lba != cacheBlockNumber_) {
if (!cacheRawBlock(lba, CACHE_FOR_READ)) return false;
}
if (fatType_ == 16) {
*value = cacheBuffer_.fat16[cluster & 0XFF];
} else {
*value = cacheBuffer_.fat32[cluster & 0X7F] & FAT32MASK;
}
return true;
}
int8_t PLEN2::ExternalSD::writeSlot(uint32_t slot, const uint8_t data[], uint8_t write_size)
{
uint32_t block;
uint16_t offset;
#if DEBUG
PROFILING("ExternalSD::writeSlot()");
#endif
if ( (slot >= SLOT_END)
|| (write_size > SLOT_SIZE)
)
{
#if DEBUG
System::debugSerial().print(F(">>> bad argument! : slot = "));
System::debugSerial().print(slot);
System::debugSerial().print(F(", or write_size = "));
System::debugSerial().println(write_size);
#endif
return -1;
}
block = 32 + (slot * CHUNK_SIZE) / 512;
offset = (slot * CHUNK_SIZE) % 512;
#if DEBUG
System::debugSerial().print(F("writeSlot slot = "));
System::debugSerial().print(slot);
System::debugSerial().print(F(", block = "));
System::debugSerial().print(block);
System::debugSerial().print(F(", offset = "));
System::debugSerial().println(offset);
#endif
if (cacheRawBlock(block, CACHE_FOR_WRITE)) {
memcpy(&mCacheBuf[offset], data, write_size);
cacheFlush();
return 0;
}
return -1;
}
int8_t PLEN2::ExternalSD::readSlot(uint32_t slot, uint8_t data[], uint8_t read_size)
{
uint32_t block;
uint16_t offset;
#if DEBUG
PROFILING("ExternalSD::readSlot()");
#endif
if ( (slot >= SLOT_END)
|| (read_size > SLOT_SIZE)
)
{
#if DEBUG
System::debugSerial().print(F(">>> bad argument! : slot = "));
System::debugSerial().print(slot);
System::debugSerial().print(F(", or read_size = "));
System::debugSerial().println(read_size);
#endif
return -1;
}
block = 32 + (slot * CHUNK_SIZE) / 512;
offset = (slot * CHUNK_SIZE) % 512;
#if DEBUG
System::debugSerial().print(F("readSlot slot = "));
System::debugSerial().print(slot);
System::debugSerial().print(F(", block = "));
System::debugSerial().print(block);
System::debugSerial().print(F(", offset = "));
System::debugSerial().println(offset);
#endif
if (cacheRawBlock(block, CACHE_FOR_READ)) {
memcpy(data, &mCacheBuf[offset], read_size);
return read_size;
}
return -1;
}
/**
* Initialize a FAT volume.
*
* \param[in] dev The SD card where the volume is located.
*
* \param[in] part The partition to be used. Legal values for \a part are
* 1-4 to use the corresponding partition on a device formatted with
* a MBR, Master Boot Record, or zero if the device is formatted as
* a super floppy with the FAT boot sector in block zero.
*
* \return The value one, true, is returned for success and
* the value zero, false, is returned for failure. Reasons for
* failure include not finding a valid partition, not finding a valid
* FAT file system in the specified partition or an I/O error.
*/
uint8_t SdVolume::init(Sd2Card* dev, uint8_t part)
{
uint32_t volumeStartBlock = 0;
sdCard_ = dev;
// if part == 0 assume super floppy with FAT boot sector in block zero
// if part > 0 assume mbr volume with partition table
if (part)
{
if (part > 4)
{
DEBUG_SDFAT_PRINTLN("Error: SdVolume::init() MBR");
return false;
}
if (!cacheRawBlock(volumeStartBlock, CACHE_FOR_READ))
{
DEBUG_SDFAT_PRINTLN("Error: SdVolume::init() Cache for read");
return false;
}
part_t* p = &cacheBuffer_.mbr.part[part-1];
if ((p->boot & 0X7F) !=0 ||
p->totalSectors < 100 ||
p->firstSector == 0)
{
// not a valid partition
DEBUG_SDFAT_PRINTLN("Error: SdVolume::init() Invalid partition");
return false;
}
volumeStartBlock = p->firstSector;
}
if (!cacheRawBlock(volumeStartBlock, CACHE_FOR_READ))
{
DEBUG_SDFAT_PRINTLN("Error: SdVolume::init() Cache for read2");
return false;
}
bpb_t* bpb = &cacheBuffer_.fbs.bpb;
if (bpb->bytesPerSector != 512 ||
bpb->fatCount == 0 ||
bpb->reservedSectorCount == 0 ||
bpb->sectorsPerCluster == 0)
{
// not valid FAT volume
DEBUG_SDFAT_PRINTLN("Error: SdVolume::init() invalid FAT volume");
return false;
}
fatCount_ = bpb->fatCount;
blocksPerCluster_ = bpb->sectorsPerCluster;
// determine shift that is same as multiply by blocksPerCluster_
clusterSizeShift_ = 0;
while (blocksPerCluster_ != (1 << clusterSizeShift_))
{
// error if not power of 2
if (clusterSizeShift_++ > 7)
{
return false;
DEBUG_SDFAT_PRINTLN("Error: SdVolume::init() not power of 2");
}
}
blocksPerFat_ = bpb->sectorsPerFat16 ?
bpb->sectorsPerFat16 : bpb->sectorsPerFat32;
fatStartBlock_ = volumeStartBlock + bpb->reservedSectorCount;
// count for FAT16 zero for FAT32
rootDirEntryCount_ = bpb->rootDirEntryCount;
// directory start for FAT16 dataStart for FAT32
rootDirStart_ = fatStartBlock_ + bpb->fatCount * blocksPerFat_;
// data start for FAT16 and FAT32
dataStartBlock_ = rootDirStart_ + ((32 * bpb->rootDirEntryCount + 511)/512);
// total blocks for FAT16 or FAT32
uint32_t totalBlocks = bpb->totalSectors16 ?
bpb->totalSectors16 : bpb->totalSectors32;
// total data blocks
clusterCount_ = totalBlocks - (dataStartBlock_ - volumeStartBlock);
// divide by cluster size to get cluster count
clusterCount_ >>= clusterSizeShift_;
// FAT type is determined by cluster count
if (clusterCount_ < 4085)
{
fatType_ = 12;
}
else if (clusterCount_ < 65525)
{
fatType_ = 16;
}
else
{
rootDirStart_ = bpb->fat32RootCluster;
fatType_ = 32;
}
return true;
}
