Use real firmware file size in the VirtualFAT layer, clean up FAT12 chain update...

diff --git a/Bootloaders/Incomplete/MassStorage/Lib/VirtualFAT.c b/Bootloaders/Incomplete/MassStorage/Lib/VirtualFAT.c
index b111a53..d43ac86 100644 (file)
--- a/Bootloaders/Incomplete/MassStorage/Lib/VirtualFAT.c
+++ b/Bootloaders/Incomplete/MassStorage/Lib/VirtualFAT.c
@@ -64,10 +64,33 @@ static FATDirectoryEntry_t FirmwareFileEntry =
                .CreationTime    = FAT_TIME(1, 1, 0),
                .CreationDate    = FAT_DATE(14, 2, 1989),
                .StartingCluster = 2,
-               .FileSizeBytes   = 2049,
+               .FileSizeBytes   = FIRMWARE_FILE_SIZE,
        };
 
-static void WriteBlock(uint16_t BlockNumber)
+
+static void UpdateFAT12ClusterEntry(uint8_t* FATTable,
+                                    const uint16_t Index,
+                                    const uint16_t ChainEntry)
+{
+       /* Calculate the starting offset of the cluster entry in the FAT12 table */
+       uint8_t FATOffset   =   (Index * 3) / 2;
+       bool    UpperNibble = (((Index * 3) % 2) != 0);
+
+       /* Check if the start of the entry is at an upper nibble of the byte, fill
+        * out FAT12 entry as required */
+       if (UpperNibble)
+       {
+               FATTable[FATOffset]     = (FATTable[FATOffset] & 0x0F) | ((ChainEntry & 0x0F) << 4);
+               FATTable[FATOffset + 1] = (ChainEntry >> 4);
+       }
+       else
+       {
+               FATTable[FATOffset]     = ChainEntry;
+               FATTable[FATOffset + 1] = (FATTable[FATOffset] & 0xF0) | (ChainEntry >> 8);
+       }
+}
+
+static void WriteBlock(const uint16_t BlockNumber)
 {
        uint8_t BlockBuffer[512];
 
@@ -82,67 +105,48 @@ 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)
+static void ReadBlock(const uint16_t BlockNumber)
 {
        uint8_t BlockBuffer[512];
        memset(BlockBuffer, 0x00, sizeof(BlockBuffer));
 
-       printf("READ %d", BlockNumber);
-
        switch (BlockNumber)
        {
                case 0:
                        memcpy(BlockBuffer, &BootBlock, sizeof(FATBootBlock_t));
-                       printf(" <B>\r\n");
                        break;
 
                case 1:
                case 2:
-                       printf(" <F>\r\n");
-
                        /* Cluster 0: Media type/Reserved */
-                       WriteFAT12ClusterEntry(BlockBuffer, 0, 0xF00 | BootBlock.MediaDescriptor);
+                       UpdateFAT12ClusterEntry(BlockBuffer, 0, 0xF00 | BootBlock.MediaDescriptor);
 
                        /* Cluster 1: Reserved */
-                       WriteFAT12ClusterEntry(BlockBuffer, 1, 0xFFF);
+                       UpdateFAT12ClusterEntry(BlockBuffer, 1, 0xFFF);
 
                        /* Cluster 2 onwards: Cluster chain of FIRMWARE.BIN */
-                       for (uint16_t i = 0; i < FILE_CLUSTERS(2049); i++)
-                         WriteFAT12ClusterEntry(BlockBuffer, i+2, i+3);
+                       for (uint16_t i = 0; i < FILE_CLUSTERS(FIRMWARE_FILE_SIZE); i++)
+                         UpdateFAT12ClusterEntry(BlockBuffer, i+2, i+3);
 
                        /* Mark last cluster as end of file */
-                       WriteFAT12ClusterEntry(BlockBuffer, FILE_CLUSTERS(2049) + 1, 0xFFF);
+                       UpdateFAT12ClusterEntry(BlockBuffer, FILE_CLUSTERS(FIRMWARE_FILE_SIZE) + 1, 0xFFF);
                        break;
 
                case 3:
-                       printf("<R>\r\n");
                        memcpy(BlockBuffer, &FirmwareFileEntry, sizeof(FATDirectoryEntry_t));
                        break;
 
                default:
-                       if ((BlockNumber >= 4) && (BlockNumber < (4 + FILE_CLUSTERS(FIRMWARE_FILE_SIZE))))
+                       if ((BlockNumber >= 4) && (BlockNumber < (4 + (FIRMWARE_FILE_SIZE / SECTOR_SIZE_BYTES))))
                        {
-                               printf("<D>\r\n");
+//                             printf("<D>\r\n");
 
                                for (uint16_t i = 0; i < 512; i++)
-                                 BlockBuffer[i] = '0' + BlockNumber; //A' + (i % 26);
+                                 BlockBuffer[i] = 'A' + (i % 26);
+                       }
+                       else
+                       {
+                               printf("INVALID %d\r\n", BlockNumber);
                        }
 
                        break;