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| author | Dean Camera <dean@fourwalledcubicle.com> | 2013-03-09 08:48:00 +0000 |
|---|---|---|
| committer | Dean Camera <dean@fourwalledcubicle.com> | 2013-03-09 08:48:00 +0000 |
| commit | f00754ed9787390f16092652230d0b9fabcb64d5 (patch) | |
| tree | 5bfc18aad544d7225e01a8695e8a5e2edfacc0c2 /Bootloaders | |
| parent | 6da1677bc33608eddb87b65b86dfc5881dd6c6e8 (diff) | |
| download | lufa-f00754ed9787390f16092652230d0b9fabcb64d5.tar.gz lufa-f00754ed9787390f16092652230d0b9fabcb64d5.tar.bz2 lufa-f00754ed9787390f16092652230d0b9fabcb64d5.zip | |
FAT heuristics mean a disk as small as the one emulated in the incomplete Mass Storage bootloader *must* be FAT12, not FAT16. Update to use a FAT12 cluster chain.
Diffstat (limited to 'Bootloaders')
| -rw-r--r-- | Bootloaders/Incomplete/MassStorage/Lib/VirtualFAT.c | 34 |
1 files changed, 24 insertions, 10 deletions
diff --git a/Bootloaders/Incomplete/MassStorage/Lib/VirtualFAT.c b/Bootloaders/Incomplete/MassStorage/Lib/VirtualFAT.c index 7a248d87e..b111a5352 100644 --- a/Bootloaders/Incomplete/MassStorage/Lib/VirtualFAT.c +++ b/Bootloaders/Incomplete/MassStorage/Lib/VirtualFAT.c @@ -42,15 +42,15 @@ static const FATBootBlock_t BootBlock = .TotalSectors16 = LUN_MEDIA_BLOCKS, .MediaDescriptor = 0xF8, .SectorsPerFAT = 1, - .SectorsPerTrack = 32, - .Heads = 64, + .SectorsPerTrack = LUN_MEDIA_BLOCKS % 64, + .Heads = LUN_MEDIA_BLOCKS / 64, .HiddenSectors = 0, .TotalSectors32 = 0, .PhysicalDriveNum = 0, .ExtendedBootRecordSig = 0x29, .VolumeSerialNumber = 0x12345678, .VolumeLabel = "LUFA BOOT ", - .FilesystemIdentifier = "FAT16 ", + .FilesystemIdentifier = "FAT12 ", .BootstrapProgram = {0}, .MagicSignature = 0xAA55, }; @@ -67,7 +67,6 @@ static FATDirectoryEntry_t FirmwareFileEntry = .FileSizeBytes = 2049, }; - static void WriteBlock(uint16_t BlockNumber) { uint8_t BlockBuffer[512]; @@ -83,6 +82,23 @@ static void WriteBlock(uint16_t BlockNumber) // TODO: Write to FLASH } +void WriteFAT12ClusterEntry(uint8_t* FATTable, uint8_t Index, uint16_t NextEntry) +{ + uint8_t StartOffset = ((uint16_t)Index * 3) / 2; + + /* Check if the start of the entry is at an upper nibble of the byte */ + if (((uint16_t)Index * 3) % 2) + { + FATTable[StartOffset] |= ((NextEntry & 0x0F) << 4); + FATTable[StartOffset + 1] = (NextEntry >> 4); + } + else + { + FATTable[StartOffset] = NextEntry; + FATTable[StartOffset + 1] = (NextEntry >> 8); + } +} + static void ReadBlock(uint16_t BlockNumber) { uint8_t BlockBuffer[512]; @@ -102,19 +118,17 @@ static void ReadBlock(uint16_t BlockNumber) printf(" <F>\r\n"); /* Cluster 0: Media type/Reserved */ - ((uint16_t*)&BlockBuffer)[0] = 0xFF00 | BootBlock.MediaDescriptor; + WriteFAT12ClusterEntry(BlockBuffer, 0, 0xF00 | BootBlock.MediaDescriptor); /* Cluster 1: Reserved */ - ((uint16_t*)&BlockBuffer)[1] = 0xFFFF; + WriteFAT12ClusterEntry(BlockBuffer, 1, 0xFFF); /* Cluster 2 onwards: Cluster chain of FIRMWARE.BIN */ for (uint16_t i = 0; i < FILE_CLUSTERS(2049); i++) - { - ((uint16_t*)&BlockBuffer)[i + 2] = i + 3; - } + WriteFAT12ClusterEntry(BlockBuffer, i+2, i+3); /* Mark last cluster as end of file */ - ((uint16_t*)&BlockBuffer)[FILE_CLUSTERS(2049) + 1] = 0xFFFF; + WriteFAT12ClusterEntry(BlockBuffer, FILE_CLUSTERS(2049) + 1, 0xFFF); break; case 3: |