Bootloaders/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 /** \file
  32  *
  33  *  Virtualized FAT12 filesystem implementation, to perform self-programming
  34  *  in response to read and write requests to the virtual filesystem by the
  35  *  host PC.
  36  */
  37
  38 #define  INCLUDE_FROM_VIRTUAL_FAT_C
  39 #include "VirtualFAT.h"
  40
  41 /** FAT filesystem boot sector block, must be the first sector on the physical
  42  *  disk so that the host can identify the presence of a FAT filesystem. This
  43  *  block is truncated; normally a large bootstrap section is located near the
  44  *  end of the block for booting purposes however as this is not meant to be a
  45  *  bootable disk it is omitted for space reasons.
  46  *
  47  *  \note When returning the boot block to the host, the magic signature 0xAA55
  48  *        must be added to the very end of the block to identify it as a boot
  49  *        block.
  50  */
  51 static const FATBootBlock_t BootBlock =
  52         {
  53                 .Bootstrap               = {0xEB, 0x3C, 0x90},
  54                 .Description             = "mkdosfs",
  55                 .SectorSize              = SECTOR_SIZE_BYTES,
  56                 .SectorsPerCluster       = SECTOR_PER_CLUSTER,
  57                 .ReservedSectors         = 1,
  58                 .FATCopies               = 2,
  59                 .RootDirectoryEntries    = (SECTOR_SIZE_BYTES / sizeof(FATDirectoryEntry_t)),
  60                 .TotalSectors16          = LUN_MEDIA_BLOCKS,
  61                 .MediaDescriptor         = 0xF8,
  62                 .SectorsPerFAT           = 1,
  63                 .SectorsPerTrack         = (LUN_MEDIA_BLOCKS % 64),
  64                 .Heads                   = (LUN_MEDIA_BLOCKS / 64),
  65                 .HiddenSectors           = 0,
  66                 .TotalSectors32          = 0,
  67                 .PhysicalDriveNum        = 0,
  68                 .ExtendedBootRecordSig   = 0x29,
  69                 .VolumeSerialNumber      = 0x12345678,
  70                 .VolumeLabel             = "LUFA BOOT  ",
  71                 .FilesystemIdentifier    = "FAT12   ",
  72         };
  73
  74 /** FAT 8.3 style directory entry, for the virtual FLASH contents file. */
  75 static FATDirectoryEntry_t FirmwareFileEntries[] =
  76         {
  77                 /* Root volume label entry; disk label is contained in the Filename and
  78                  * Extension fields (concatenated) with a special attribute flag - other
  79                  * fields are ignored. Should be the same as the label in the boot block.
  80                  */
  81                 {
  82                         .MSDOS_Directory =
  83                                 {
  84                                         .Name            = "LUFA BOOT  ",
  85                                         .Attributes      = FAT_FLAG_VOLUME_NAME,
  86                                         .Reserved        = {0},
  87                                         .CreationTime    = 0,
  88                                         .CreationDate    = 0,
  89                                         .StartingCluster = 0,
  90                                         .Reserved2       = 0,
  91                                 }
  92                 },
  93
  94                 /* VFAT Long File Name entry for the virtual firmware file; required to
  95                  * prevent corruption of systems that are unable to detect the device
  96                  * as being a legacy MSDOS style FAT12 volume to prevent corruption. */
  97                 {
  98                         .VFAT_LongFileName =
  99                                 {
 100                                         .Ordinal         = FAT_ORDINAL_LAST_ENTRY | 1,
 101                                         .Attribute       = FAT_FLAG_LONG_FILE_NAME,
 102                                         .Reserved1       = 0,
 103                                         .Reserved2       = 0,
 104
 105                                         .Checksum        = 0x57,
 106
 107                                         .Unicode1        = 'F',
 108                                         .Unicode2        = 'I',
 109                                         .Unicode3        = 'R',
 110                                         .Unicode4        = 'M',
 111                                         .Unicode5        = 'W',
 112                                         .Unicode6        = 'A',
 113                                         .Unicode7        = 'R',
 114                                         .Unicode8        = 'E',
 115                                         .Unicode9        = '.',
 116                                         .Unicode10       = 'B',
 117                                         .Unicode11       = 'I',
 118                                         .Unicode12       = 'N',
 119                                         .Unicode13       = 0,
 120                                 }
 121                 },
 122
 123                 /* MSDOS file entry for the virtual Firmware image. */
 124                 {
 125                         .MSDOS_File =
 126                                 {
 127                                         .Filename        = "FIRMWARE",
 128                                         .Extension       = "BIN",
 129                                         .Attributes      = 0,
 130                                         .Reserved        = {0},
 131                                         .CreationTime    = FAT_TIME(1, 1, 0),
 132                                         .CreationDate    = FAT_DATE(14, 2, 1989),
 133                                         .StartingCluster = 2,
 134                                         .FileSizeBytes   = FIRMWARE_FILE_SIZE_BYTES,
 135                                 }
 136                 },
 137         };
 138
 139
 140 /** Updates a FAT12 cluster entry in the FAT file table with the specified next
 141  *  chain index. If the cluster is the last in the file chain, the magic value
 142  *  0xFFF is used.
 143  *
 144  *  \note FAT data cluster indexes are offset by 2, so that cluster 2 is the
 145  *        first file data cluster on the disk. See the FAT specification.
 146  *
 147  *  \param[out]  FATTable    Pointer to the FAT12 allocation table
 148  *  \param[in]   Index       Index of the cluster entry to update
 149  *  \param[in]   ChainEntry  Next cluster index in the file chain
 150  */
 151 static void UpdateFAT12ClusterEntry(uint8_t* const FATTable,
 152                                     const uint16_t Index,
 153                                     const uint16_t ChainEntry)
 154 {
 155         /* Calculate the starting offset of the cluster entry in the FAT12 table */
 156         uint8_t FATOffset   = (Index + (Index >> 1));
 157         bool    UpperNibble = ((Index & 1) != 0);
 158
 159         /* Check if the start of the entry is at an upper nibble of the byte, fill
 160          * out FAT12 entry as required */
 161         if (UpperNibble)
 162         {
 163                 FATTable[FATOffset]     = (FATTable[FATOffset] & 0x0F) | ((ChainEntry & 0x0F) << 4);
 164                 FATTable[FATOffset + 1] = (ChainEntry >> 4);
 165         }
 166         else
 167         {
 168                 FATTable[FATOffset]     = ChainEntry;
 169                 FATTable[FATOffset + 1] = (FATTable[FATOffset] & 0xF0) | (ChainEntry >> 8);
 170         }
 171 }
 172
 173 /** Writes a block of data to the virtual FAT filesystem, from the USB Mass
 174  *  Storage interface.
 175  *
 176  *  \param[in]  BlockNumber  Index of the block to write.
 177  */
 178 static void WriteVirtualBlock(const uint16_t BlockNumber)
 179 {
 180         uint8_t BlockBuffer[SECTOR_SIZE_BYTES];
 181
 182         /* Buffer the entire block to be written from the host */
 183         Endpoint_Read_Stream_LE(BlockBuffer, sizeof(BlockBuffer), NULL);
 184         Endpoint_ClearOUT();
 185
 186         if ((BlockNumber >= 4) && (BlockNumber < (4 + FILE_SECTORS(FIRMWARE_FILE_SIZE_BYTES))))
 187         {
 188                 #if (FLASHEND > 0xFFFF)
 189                 uint32_t WriteFlashAddress = (uint32_t)(BlockNumber - 4) * SECTOR_SIZE_BYTES;
 190                 #else
 191                 uint16_t WriteFlashAddress = (uint16_t)(BlockNumber - 4) * SECTOR_SIZE_BYTES;
 192                 #endif
 193
 194                 for (uint16_t i = 0; i < SECTOR_SIZE_BYTES; i += 2)
 195                 {
 196                         if ((WriteFlashAddress % SPM_PAGESIZE) == 0)
 197                         {
 198                                 /* Erase the given FLASH page, ready to be programmed */
 199                                 BootloaderAPI_ErasePage(WriteFlashAddress);
 200                         }
 201
 202                         /* Write the next data word to the FLASH page */
 203                         BootloaderAPI_FillWord(WriteFlashAddress, (BlockBuffer[i + 1] << 8) | BlockBuffer[i]);
 204                         WriteFlashAddress += 2;
 205
 206                         if ((WriteFlashAddress % SPM_PAGESIZE) == 0)
 207                         {
 208                                 /* Write the filled FLASH page to memory */
 209                                 BootloaderAPI_WritePage(WriteFlashAddress - SPM_PAGESIZE);
 210                         }
 211                 }
 212         }
 213 }
 214
 215 /** Reads a block of data from the virtual FAT filesystem, and sends it to the
 216  *  host via the USB Mass Storage interface.
 217  *
 218  *  \param[in]  BlockNumber  Index of the block to read.
 219  */
 220 static void ReadVirtualBlock(const uint16_t BlockNumber)
 221 {
 222         uint8_t BlockBuffer[SECTOR_SIZE_BYTES];
 223         memset(BlockBuffer, 0x00, sizeof(BlockBuffer));
 224
 225         switch (BlockNumber)
 226         {
 227                 case 0: /* Block 0: Boot block sector */
 228                         memcpy(BlockBuffer, &BootBlock, sizeof(FATBootBlock_t));
 229
 230                         /* Add the magic signature to the end of the block */
 231                         BlockBuffer[SECTOR_SIZE_BYTES - 2] = 0x55;
 232                         BlockBuffer[SECTOR_SIZE_BYTES - 1] = 0xAA;
 233                         break;
 234
 235                 case 1: /* Block 1: First FAT12 cluster chain copy */
 236                 case 2: /* Block 2: Second FAT12 cluster chain copy */
 237                         /* Cluster 0: Media type/Reserved */
 238                         UpdateFAT12ClusterEntry(BlockBuffer, 0, 0xF00 | BootBlock.MediaDescriptor);
 239
 240                         /* Cluster 1: Reserved */
 241                         UpdateFAT12ClusterEntry(BlockBuffer, 1, 0xFFF);
 242
 243                         /* Cluster 2 onwards: Cluster chain of FIRMWARE.BIN */
 244                         for (uint16_t i = 0; i < FILE_CLUSTERS(FIRMWARE_FILE_SIZE_BYTES); i++)
 245                           UpdateFAT12ClusterEntry(BlockBuffer, i+2, i+3);
 246
 247                         /* Mark last cluster as end of file */
 248                         UpdateFAT12ClusterEntry(BlockBuffer, FILE_CLUSTERS(FIRMWARE_FILE_SIZE_BYTES) + 1, 0xFFF);
 249                         break;
 250
 251                 case 3: /* Block 3: Root file entries */
 252                         memcpy(BlockBuffer, FirmwareFileEntries, sizeof(FirmwareFileEntries));
 253                         break;
 254
 255                 default: /* Blocks 4 onwards: Data allocation section */
 256                         if ((BlockNumber >= 4) && (BlockNumber < (4 + FILE_SECTORS(FIRMWARE_FILE_SIZE_BYTES))))
 257                         {
 258                                 #if (FLASHEND > 0xFFFF)
 259                                 uint32_t ReadFlashAddress = (uint32_t)(BlockNumber - 4) * SECTOR_SIZE_BYTES;
 260
 261                                 for (uint16_t i = 0; i < SECTOR_SIZE_BYTES; i++)
 262                                   BlockBuffer[i] = pgm_read_byte_far(ReadFlashAddress++);
 263                                 #else
 264                                 uint16_t ReadFlashAddress = (uint16_t)(BlockNumber - 4) * SECTOR_SIZE_BYTES;
 265
 266                                 for (uint16_t i = 0; i < SECTOR_SIZE_BYTES; i++)
 267                                   BlockBuffer[i] = pgm_read_byte(ReadFlashAddress++);
 268                                 #endif
 269                         }
 270
 271                         break;
 272         }
 273
 274         /* Write the entire read block Buffer to the host */
 275         Endpoint_Write_Stream_LE(BlockBuffer, sizeof(BlockBuffer), NULL);
 276         Endpoint_ClearIN();
 277 }
 278
 279 /** Writes a number of blocks to the virtual FAT file system, from the host
 280  *  PC via the USB Mass Storage interface.
 281  *
 282  *  \param[in] BlockAddress     Data block starting address for the write sequence
 283  *  \param[in] TotalBlocks      Number of blocks of data to write
 284  */
 285 void VirtualFAT_WriteBlocks(const uint16_t BlockAddress,
 286                             uint16_t TotalBlocks)
 287 {
 288         uint16_t CurrentBlock = (uint16_t)BlockAddress;
 289
 290         /* Emulated FAT is performed per-block, pass each requested block index
 291          * to the emulated FAT block write function */
 292         while (TotalBlocks--)
 293           WriteVirtualBlock(CurrentBlock++);
 294 }
 295
 296 /** Reads a number of blocks from the virtual FAT file system, and sends them
 297  *  to the host PC via the USB Mass Storage interface.
 298  *
 299  *  \param[in] BlockAddress     Data block starting address for the read sequence
 300  *  \param[in] TotalBlocks      Number of blocks of data to read
 301  */
 302 void VirtualFAT_ReadBlocks(const uint16_t BlockAddress,
 303                            uint16_t TotalBlocks)
 304 {
 305         uint16_t CurrentBlock = (uint16_t)BlockAddress;
 306
 307         /* Emulated FAT is performed per-block, pass each requested block index
 308          * to the emulated FAT block read function */
 309         while (TotalBlocks--)
 310           ReadVirtualBlock(CurrentBlock++);
 311 }
 312