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Clean up the VirtualFAT implementation.

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This commit is contained in:
Dean Camera 2013-03-30 15:13:42 +00:00
parent b956fedeeb
commit 829ecefe41
1 changed files with 10 additions and 11 deletions
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21
Bootloaders/MassStorage/Lib/VirtualFAT.c
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@ -139,11 +139,12 @@ static FATDirectoryEntry_t FirmwareFileEntries[] =
},
};
/** Starting block of the virtual firmware file image on disk. On Windows, files
* are (usually?) replaced using the original file's physical sectors. On Linux
* file replacements are performed with an offset.
/** Starting cluster of the virtual firmware file on disk, tracked so that the
* offset from the start of the data sector can be determined. On Windows
* systems files are usually replaced using the original file's disk clusters,
* while Linux appears to overwrite with an offset which must be compensated for.
*/
static uint16_t FileStartBlock = DISK_BLOCK_DataStartBlock;
static uint16_t* FileStartCluster = &FirmwareFileEntries[DISK_FILE_ENTRY_FirmwareMSDOS].MSDOS_File.StartingCluster;
/** Updates a FAT12 cluster entry in the FAT file table with the specified next
@ -192,9 +193,12 @@ static void ReadWriteFirmwareFileBlock(const uint16_t BlockNumber,
uint8_t* BlockBuffer,
const bool Read)
{
uint16_t FileStartBlock = DISK_BLOCK_DataStartBlock + (*FileStartCluster - 2) * SECTOR_PER_CLUSTER;
uint16_t FileEndBlock = FileStartBlock + (FILE_SECTORS(FIRMWARE_FILE_SIZE_BYTES) - 1);
/* Range check the write request - abort if requested block is not within the
* virtual firmware file sector range */
if (!((BlockNumber >= FileStartBlock) && (BlockNumber < (FileStartBlock + FILE_SECTORS(FIRMWARE_FILE_SIZE_BYTES)))))
if (!((BlockNumber >= FileStartBlock) && (BlockNumber <= FileEndBlock)))
return;
#if (FLASHEND > 0xFFFF)
@ -265,11 +269,6 @@ void VirtualFAT_WriteBlock(const uint16_t BlockNumber)
/* Copy over the updated directory entries */
memcpy(FirmwareFileEntries, BlockBuffer, sizeof(FirmwareFileEntries));
/* Save the new firmware file block offset so the written and read file
* contents can be correctly mapped to the device's FLASH pages */
FileStartBlock = DISK_BLOCK_DataStartBlock +
(FirmwareFileEntries[DISK_FILE_ENTRY_FirmwareMSDOS].MSDOS_File.StartingCluster - 2) * SECTOR_PER_CLUSTER;
break;
default:
@ -311,7 +310,7 @@ void VirtualFAT_ReadBlock(const uint16_t BlockNumber)
/* Cluster 2 onwards: Cluster chain of FIRMWARE.BIN */
for (uint16_t i = 0; i <= FILE_CLUSTERS(FIRMWARE_FILE_SIZE_BYTES); i++)
{
uint16_t CurrentCluster = FirmwareFileEntries[DISK_FILE_ENTRY_FirmwareMSDOS].MSDOS_File.StartingCluster + i;
uint16_t CurrentCluster = *FileStartCluster + i;
uint16_t NextCluster = CurrentCluster + 1;
/* Mark last cluster as end of file */