Bootloaders/Incomplete/MassStorage/Lib/VirtualFAT.c

   1 /*
   2              LUFA Library
   3      Copyright (C) Dean Camera, 2013.
   4
   5   dean [at] fourwalledcubicle [dot] com
   6            www.lufa-lib.org
   7 */
   8
   9 /*
  10   Copyright 2013  Dean Camera (dean [at] fourwalledcubicle [dot] com)
  11
  12   Permission to use, copy, modify, distribute, and sell this
  13   software and its documentation for any purpose is hereby granted
  14   without fee, provided that the above copyright notice appear in
  15   all copies and that both that the copyright notice and this
  16   permission notice and warranty disclaimer appear in supporting
  17   documentation, and that the name of the author not be used in
  18   advertising or publicity pertaining to distribution of the
  19   software without specific, written prior permission.
  20
  21   The author disclaims all warranties with regard to this
  22   software, including all implied warranties of merchantability
  23   and fitness.  In no event shall the author be liable for any
  24   special, indirect or consequential damages or any damages
  25   whatsoever resulting from loss of use, data or profits, whether
  26   in an action of contract, negligence or other tortious action,
  27   arising out of or in connection with the use or performance of
  28   this software.
  29 */
  30
  31 #include "VirtualFAT.h"
  32
  33 static const FATBootBlock_t BootBlock =
  34         {
  35                 .Bootstrap               = {0xEB, 0x3C, 0x90},
  36                 .Description             = "mkdosfs",
  37                 .SectorSize              = SECTOR_SIZE_BYTES,
  38                 .SectorsPerCluster       = SECTOR_PER_CLUSTER,
  39                 .ReservedSectors         = 1,
  40                 .FATCopies               = 2,
  41                 .RootDirectoryEntries    = (SECTOR_SIZE_BYTES / sizeof(FATDirectoryEntry_t)),
  42                 .TotalSectors16          = LUN_MEDIA_BLOCKS,
  43                 .MediaDescriptor         = 0xF8,
  44                 .SectorsPerFAT           = 1,
  45                 .SectorsPerTrack         = LUN_MEDIA_BLOCKS % 64,
  46                 .Heads                   = LUN_MEDIA_BLOCKS / 64,
  47                 .HiddenSectors           = 0,
  48                 .TotalSectors32          = 0,
  49                 .PhysicalDriveNum        = 0,
  50                 .ExtendedBootRecordSig   = 0x29,
  51                 .VolumeSerialNumber      = 0x12345678,
  52                 .VolumeLabel             = "LUFA BOOT  ",
  53                 .FilesystemIdentifier    = "FAT12   ",
  54                 .BootstrapProgram        = {0},
  55                 .MagicSignature          = 0xAA55,
  56         };
  57
  58 static FATDirectoryEntry_t FirmwareFileEntry =
  59         {
  60                 .Filename               = "FIRMWARE",
  61                 .Extension              = "BIN",
  62                 .Attributes             = 0,
  63                 .Reserved               = {0},
  64                 .CreationTime           = FAT_TIME(1, 1, 0),
  65                 .CreationDate           = FAT_DATE(14, 2, 1989),
  66                 .StartingCluster        = 2,
  67                 .FileSizeBytes          = FIRMWARE_FILE_SIZE,
  68         };
  69
  70
  71 static void UpdateFAT12ClusterEntry(uint8_t* FATTable,
  72                                     const uint16_t Index,
  73                                     const uint16_t ChainEntry)
  74 {
  75         /* Calculate the starting offset of the cluster entry in the FAT12 table */
  76         uint8_t FATOffset   =   (Index * 3) / 2;
  77         bool    UpperNibble = (((Index * 3) % 2) != 0);
  78
  79         /* Check if the start of the entry is at an upper nibble of the byte, fill
  80          * out FAT12 entry as required */
  81         if (UpperNibble)
  82         {
  83                 FATTable[FATOffset]     = (FATTable[FATOffset] & 0x0F) | ((ChainEntry & 0x0F) << 4);
  84                 FATTable[FATOffset + 1] = (ChainEntry >> 4);
  85         }
  86         else
  87         {
  88                 FATTable[FATOffset]     = ChainEntry;
  89                 FATTable[FATOffset + 1] = (FATTable[FATOffset] & 0xF0) | (ChainEntry >> 8);
  90         }
  91 }
  92
  93 static void WriteBlock(const uint16_t BlockNumber)
  94 {
  95         uint8_t BlockBuffer[SECTOR_SIZE_BYTES];
  96
  97         /* Buffer the entire block to be written from the host */
  98         Endpoint_Read_Stream_LE(BlockBuffer, sizeof(BlockBuffer), NULL);
  99         Endpoint_ClearOUT();
 100
 101         if ((BlockNumber >= 4) && (BlockNumber < (4 + (FIRMWARE_FILE_SIZE / SECTOR_SIZE_BYTES))))
 102         {
 103                 uint32_t WriteFlashAddress = (uint32_t)(BlockNumber - 4) * SECTOR_SIZE_BYTES;
 104
 105                 for (uint16_t i = 0; i < SECTOR_SIZE_BYTES; i += 2)
 106                 {
 107                         /* Disallow writing to the bootloader section */
 108                         if (WriteFlashAddress > BOOT_START_ADDR)
 109                           continue;
 110
 111                         if ((WriteFlashAddress % SPM_PAGESIZE) == 0)
 112                         {
 113                                 /* Erase the given FLASH page, ready to be programmed */
 114                                 boot_page_erase(WriteFlashAddress);
 115                                 boot_spm_busy_wait();
 116                         }
 117
 118                         /* Write the next data word to the FLASH page */
 119                         boot_page_fill(WriteFlashAddress, (BlockBuffer[i + 1] << 8) | BlockBuffer[i]);
 120                         WriteFlashAddress += 2;
 121
 122                         if ((WriteFlashAddress % SPM_PAGESIZE) == 0)
 123                         {
 124                                 /* Write the filled FLASH page to memory */
 125                                 boot_page_write(WriteFlashAddress - SPM_PAGESIZE);
 126                                 boot_spm_busy_wait();
 127                         }
 128                 }
 129         }
 130 }
 131
 132 static void ReadBlock(const uint16_t BlockNumber)
 133 {
 134         uint8_t BlockBuffer[SECTOR_SIZE_BYTES];
 135         memset(BlockBuffer, 0x00, sizeof(BlockBuffer));
 136
 137         switch (BlockNumber)
 138         {
 139                 case 0: /* Block 0: Boot block sector */
 140                         memcpy(BlockBuffer, &BootBlock, sizeof(FATBootBlock_t));
 141                         break;
 142
 143                 case 1: /* Block 1: First FAT12 cluster chain copy */
 144                 case 2: /* Block 2: Second FAT12 cluster chain copy */
 145                         /* Cluster 0: Media type/Reserved */
 146                         UpdateFAT12ClusterEntry(BlockBuffer, 0, 0xF00 | BootBlock.MediaDescriptor);
 147
 148                         /* Cluster 1: Reserved */
 149                         UpdateFAT12ClusterEntry(BlockBuffer, 1, 0xFFF);
 150
 151                         /* Cluster 2 onwards: Cluster chain of FIRMWARE.BIN */
 152                         for (uint16_t i = 0; i < FILE_CLUSTERS(FIRMWARE_FILE_SIZE); i++)
 153                           UpdateFAT12ClusterEntry(BlockBuffer, i+2, i+3);
 154
 155                         /* Mark last cluster as end of file */
 156                         UpdateFAT12ClusterEntry(BlockBuffer, FILE_CLUSTERS(FIRMWARE_FILE_SIZE) + 1, 0xFFF);
 157                         break;
 158
 159                 case 3: /* Block 3: Root file entries */
 160                         memcpy(BlockBuffer, &FirmwareFileEntry, sizeof(FATDirectoryEntry_t));
 161                         break;
 162
 163                 default: /* Blocks 4 onwards: Data allocation section */
 164                         if ((BlockNumber >= 4) && (BlockNumber < (4 + (FIRMWARE_FILE_SIZE / SECTOR_SIZE_BYTES))))
 165                         {
 166                                 uint32_t ReadFlashAddress = (uint32_t)(BlockNumber - 4) * SECTOR_SIZE_BYTES;
 167
 168                                 for (uint16_t i = 0; i < SECTOR_SIZE_BYTES; i++)
 169                                   BlockBuffer[i] = pgm_read_byte_far(ReadFlashAddress++);
 170                         }
 171
 172                         break;
 173         }
 174
 175         /* Write the entire read block Buffer to the host */
 176         Endpoint_Write_Stream_LE(BlockBuffer, sizeof(BlockBuffer), NULL);
 177         Endpoint_ClearIN();
 178 }
 179
 180 void VirtualFAT_WriteBlocks(USB_ClassInfo_MS_Device_t* const MSInterfaceInfo,
 181                             const uint32_t BlockAddress,
 182                             uint16_t TotalBlocks)
 183 {
 184         uint16_t CurrentBlock = (uint16_t)BlockAddress;
 185
 186         /* Emulated FAT is performed per-block, pass each requested block index
 187          * to the emulated FAT block write function */
 188         while (TotalBlocks--)
 189           WriteBlock(CurrentBlock++);
 190 }
 191
 192 void VirtualFAT_ReadBlocks(USB_ClassInfo_MS_Device_t* const MSInterfaceInfo,
 193                            const uint32_t BlockAddress,
 194                            uint16_t TotalBlocks)
 195 {
 196         uint16_t CurrentBlock = (uint16_t)BlockAddress;
 197
 198         /* Emulated FAT is performed per-block, pass each requested block index
 199          * to the emulated FAT block read function */
 200         while (TotalBlocks--)
 201           ReadBlock(CurrentBlock++);
 202 }
 203