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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.

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This commit is contained in:
Dean Camera 2013-03-09 08:48:00 +00:00
parent 6da1677bc3
commit f00754ed97
1 changed files with 24 additions and 10 deletions
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34
Bootloaders/Incomplete/MassStorage/Lib/VirtualFAT.c
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@ -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: