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 /** \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 FirmwareFileEntry =
  76         {
  77                 .Filename               = "FIRMWARE",
  78                 .Extension              = "BIN",
  79                 .Attributes             = 0,
  80                 .Reserved               = {0},
  81                 .CreationTime           = FAT_TIME(1, 1, 0),
  82                 .CreationDate           = FAT_DATE(14, 2, 1989),
  83                 .StartingCluster        = 2,
  84                 .FileSizeBytes          = FIRMWARE_FILE_SIZE_BYTES,
  85         };
  86
  87
  88 /** Updates a FAT12 cluster entry in the FAT file table with the specified next
  89  *  chain index. If the cluster is the last in the file chain, the magic value
  90  *  0xFFF is used.
  91  *
  92  *  \note FAT data cluster indexes are offset by 2, so that cluster 2 is the
  93  *        first file data cluster on the disk. See the FAT specification.
  94  *
  95  *  \param[out]  FATTable    Pointer to the FAT12 allocation table
  96  *  \param[in]   Index       Index of the cluster entry to update
  97  *  \param[in]   ChainEntry  Next cluster index in the file chain
  98  */
  99 static void UpdateFAT12ClusterEntry(uint8_t* const FATTable,
 100                                     const uint16_t Index,
 101                                     const uint16_t ChainEntry)
 102 {
 103         /* Calculate the starting offset of the cluster entry in the FAT12 table */
 104         uint8_t FATOffset   =   (Index * 3) / 2;
 105         bool    UpperNibble = (((Index * 3) % 2) != 0);
 106
 107         /* Check if the start of the entry is at an upper nibble of the byte, fill
 108          * out FAT12 entry as required */
 109         if (UpperNibble)
 110         {
 111                 FATTable[FATOffset]     = (FATTable[FATOffset] & 0x0F) | ((ChainEntry & 0x0F) << 4);
 112                 FATTable[FATOffset + 1] = (ChainEntry >> 4);
 113         }
 114         else
 115         {
 116                 FATTable[FATOffset]     = ChainEntry;
 117                 FATTable[FATOffset + 1] = (FATTable[FATOffset] & 0xF0) | (ChainEntry >> 8);
 118         }
 119 }
 120
 121 /** Writes a block of data to the virtual FAT filesystem, from the USB Mass
 122  *  Storage interface.
 123  *
 124  *  \param[in]  BlockNumber  Index of the block to write.
 125  */
 126 static void WriteVirtualBlock(const uint16_t BlockNumber)
 127 {
 128         uint8_t BlockBuffer[SECTOR_SIZE_BYTES];
 129
 130         /* Buffer the entire block to be written from the host */
 131         Endpoint_Read_Stream_LE(BlockBuffer, sizeof(BlockBuffer), NULL);
 132         Endpoint_ClearOUT();
 133
 134         if ((BlockNumber >= 4) && (BlockNumber < (4 + FILE_SECTORS(FIRMWARE_FILE_SIZE_BYTES))))
 135         {
 136                 uint32_t WriteFlashAddress = (uint32_t)(BlockNumber - 4) * SECTOR_SIZE_BYTES;
 137
 138                 for (uint16_t i = 0; i < SECTOR_SIZE_BYTES; i += 2)
 139                 {
 140                         if ((WriteFlashAddress % SPM_PAGESIZE) == 0)
 141                         {
 142                                 /* Erase the given FLASH page, ready to be programmed */
 143                                 boot_page_erase(WriteFlashAddress);
 144                                 boot_spm_busy_wait();
 145                         }
 146
 147                         /* Write the next data word to the FLASH page */
 148                         boot_page_fill(WriteFlashAddress, (BlockBuffer[i + 1] << 8) | BlockBuffer[i]);
 149                         WriteFlashAddress += 2;
 150
 151                         if ((WriteFlashAddress % SPM_PAGESIZE) == 0)
 152                         {
 153                                 /* Write the filled FLASH page to memory */
 154                                 boot_page_write(WriteFlashAddress - SPM_PAGESIZE);
 155                                 boot_spm_busy_wait();
 156                         }
 157                 }
 158         }
 159 }
 160
 161 /** Reads a block of data from the virtual FAT filesystem, and sends it to the
 162  *  host via the USB Mass Storage interface.
 163  *
 164  *  \param[in]  BlockNumber  Index of the block to read.
 165  */
 166 static void ReadVirtualBlock(const uint16_t BlockNumber)
 167 {
 168         uint8_t BlockBuffer[SECTOR_SIZE_BYTES];
 169         memset(BlockBuffer, 0x00, sizeof(BlockBuffer));
 170
 171         switch (BlockNumber)
 172         {
 173                 case 0: /* Block 0: Boot block sector */
 174                         memcpy(BlockBuffer, &BootBlock, sizeof(FATBootBlock_t));
 175
 176                         /* Add the magic signature to the end of the block */
 177                         BlockBuffer[SECTOR_SIZE_BYTES - 2] = 0x55;
 178                         BlockBuffer[SECTOR_SIZE_BYTES - 1] = 0xAA;
 179                         break;
 180
 181                 case 1: /* Block 1: First FAT12 cluster chain copy */
 182                 case 2: /* Block 2: Second FAT12 cluster chain copy */
 183                         /* Cluster 0: Media type/Reserved */
 184                         UpdateFAT12ClusterEntry(BlockBuffer, 0, 0xF00 | BootBlock.MediaDescriptor);
 185
 186                         /* Cluster 1: Reserved */
 187                         UpdateFAT12ClusterEntry(BlockBuffer, 1, 0xFFF);
 188
 189                         /* Cluster 2 onwards: Cluster chain of FIRMWARE.BIN */
 190                         for (uint16_t i = 0; i < FILE_CLUSTERS(FIRMWARE_FILE_SIZE_BYTES); i++)
 191                           UpdateFAT12ClusterEntry(BlockBuffer, i+2, i+3);
 192
 193                         /* Mark last cluster as end of file */
 194                         UpdateFAT12ClusterEntry(BlockBuffer, FILE_CLUSTERS(FIRMWARE_FILE_SIZE_BYTES) + 1, 0xFFF);
 195                         break;
 196
 197                 case 3: /* Block 3: Root file entries */
 198                         memcpy(BlockBuffer, &FirmwareFileEntry, sizeof(FATDirectoryEntry_t));
 199                         break;
 200
 201                 default: /* Blocks 4 onwards: Data allocation section */
 202                         if ((BlockNumber >= 4) && (BlockNumber < (4 + FILE_SECTORS(FIRMWARE_FILE_SIZE_BYTES))))
 203                         {
 204                                 uint32_t ReadFlashAddress = (uint32_t)(BlockNumber - 4) * SECTOR_SIZE_BYTES;
 205
 206                                 for (uint16_t i = 0; i < SECTOR_SIZE_BYTES; i++)
 207                                   BlockBuffer[i] = pgm_read_byte_far(ReadFlashAddress++);
 208                         }
 209
 210                         break;
 211         }
 212
 213         /* Write the entire read block Buffer to the host */
 214         Endpoint_Write_Stream_LE(BlockBuffer, sizeof(BlockBuffer), NULL);
 215         Endpoint_ClearIN();
 216 }
 217
 218 /** Writes a number of blocks to the virtual FAT file system, from the host
 219  *  PC via the USB Mass Storage interface.
 220  *
 221  *  \param[in] MSInterfaceInfo  Pointer to a structure containing a Mass Storage Class configuration and state
 222  *  \param[in] BlockAddress  Data block starting address for the write sequence
 223  *  \param[in] TotalBlocks   Number of blocks of data to write
 224  */
 225 void VirtualFAT_WriteBlocks(USB_ClassInfo_MS_Device_t* const MSInterfaceInfo,
 226                             const uint32_t BlockAddress,
 227                             uint16_t TotalBlocks)
 228 {
 229         uint16_t CurrentBlock = (uint16_t)BlockAddress;
 230
 231         /* Emulated FAT is performed per-block, pass each requested block index
 232          * to the emulated FAT block write function */
 233         while (TotalBlocks--)
 234           WriteVirtualBlock(CurrentBlock++);
 235 }
 236
 237 /** Reads a number of blocks from the virtual FAT file system, and sends them
 238  *  to the host PC via the USB Mass Storage interface.
 239  *
 240  *  \param[in] MSInterfaceInfo  Pointer to a structure containing a Mass Storage Class configuration and state
 241  *  \param[in] BlockAddress  Data block starting address for the read sequence
 242  *  \param[in] TotalBlocks   Number of blocks of data to read
 243  */
 244 void VirtualFAT_ReadBlocks(USB_ClassInfo_MS_Device_t* const MSInterfaceInfo,
 245                            const uint32_t BlockAddress,
 246                            uint16_t TotalBlocks)
 247 {
 248         uint16_t CurrentBlock = (uint16_t)BlockAddress;
 249
 250         /* Emulated FAT is performed per-block, pass each requested block index
 251          * to the emulated FAT block read function */
 252         while (TotalBlocks--)
 253           ReadVirtualBlock(CurrentBlock++);
 254 }
 255