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         /* Wait until endpoint is ready before continuing */
  98         if (Endpoint_WaitUntilReady())
  99           return;
 100
 101         Endpoint_Read_Stream_LE(BlockBuffer, sizeof(BlockBuffer), NULL);
 102         Endpoint_ClearOUT();
 103
 104         if ((BlockNumber >= 4) && (BlockNumber < (4 + (FIRMWARE_FILE_SIZE / SECTOR_SIZE_BYTES))))
 105         {
 106                 uint32_t WriteFlashAddress = (uint32_t)(BlockNumber - 4) * SECTOR_SIZE_BYTES;
 107
 108                 for (uint16_t i = 0; i < SECTOR_SIZE_BYTES; i += 2)
 109                 {
 110                         /* Disallow writing to the bootloader section */
 111                         if (WriteFlashAddress > BOOT_START_ADDR)
 112                           continue;
 113
 114                         if ((WriteFlashAddress % SPM_PAGESIZE) == 0)
 115                         {
 116                                 /* Erase the given FLASH page, ready to be programmed */
 117                                 boot_page_erase(WriteFlashAddress);
 118                                 boot_spm_busy_wait();
 119                         }
 120
 121                         /* Write the next data word to the FLASH page */
 122                         boot_page_fill(WriteFlashAddress, (BlockBuffer[i + 1] << 8) | BlockBuffer[i]);
 123                         WriteFlashAddress += 2;
 124
 125                         if ((WriteFlashAddress % SPM_PAGESIZE) == 0)
 126                         {
 127                                 /* Write the filled FLASH page to memory */
 128                                 boot_page_write(WriteFlashAddress - SPM_PAGESIZE);
 129                                 boot_spm_busy_wait();
 130                         }
 131                 }
 132         }
 133 }
 134
 135 static void ReadBlock(const uint16_t BlockNumber)
 136 {
 137         uint8_t BlockBuffer[SECTOR_SIZE_BYTES];
 138         memset(BlockBuffer, 0x00, sizeof(BlockBuffer));
 139
 140         switch (BlockNumber)
 141         {
 142                 case 0:
 143                         memcpy(BlockBuffer, &BootBlock, sizeof(FATBootBlock_t));
 144                         break;
 145
 146                 case 1:
 147                 case 2:
 148                         /* Cluster 0: Media type/Reserved */
 149                         UpdateFAT12ClusterEntry(BlockBuffer, 0, 0xF00 | BootBlock.MediaDescriptor);
 150
 151                         /* Cluster 1: Reserved */
 152                         UpdateFAT12ClusterEntry(BlockBuffer, 1, 0xFFF);
 153
 154                         /* Cluster 2 onwards: Cluster chain of FIRMWARE.BIN */
 155                         for (uint16_t i = 0; i < FILE_CLUSTERS(FIRMWARE_FILE_SIZE); i++)
 156                           UpdateFAT12ClusterEntry(BlockBuffer, i+2, i+3);
 157
 158                         /* Mark last cluster as end of file */
 159                         UpdateFAT12ClusterEntry(BlockBuffer, FILE_CLUSTERS(FIRMWARE_FILE_SIZE) + 1, 0xFFF);
 160                         break;
 161
 162                 case 3:
 163                         memcpy(BlockBuffer, &FirmwareFileEntry, sizeof(FATDirectoryEntry_t));
 164                         break;
 165
 166                 default:
 167                         if ((BlockNumber >= 4) && (BlockNumber < (4 + (FIRMWARE_FILE_SIZE / SECTOR_SIZE_BYTES))))
 168                         {
 169                                 uint32_t ReadFlashAddress = (uint32_t)(BlockNumber - 4) * SECTOR_SIZE_BYTES;
 170
 171                                 for (uint16_t i = 0; i < SECTOR_SIZE_BYTES; i++)
 172                                   BlockBuffer[i] = pgm_read_byte_far(ReadFlashAddress++);
 173                         }
 174
 175                         break;
 176         }
 177
 178         /* Wait until endpoint is ready before continuing */
 179         if (Endpoint_WaitUntilReady())
 180           return;
 181
 182         Endpoint_Write_Stream_LE(BlockBuffer, sizeof(BlockBuffer), NULL);
 183         Endpoint_ClearIN();
 184 }
 185
 186 void VirtualFAT_WriteBlocks(USB_ClassInfo_MS_Device_t* const MSInterfaceInfo,
 187                             const uint32_t BlockAddress,
 188                             uint16_t TotalBlocks)
 189 {
 190         uint16_t CurrentBlock = (uint16_t)BlockAddress;
 191
 192         /* Emulated FAT is performed per-block, pass each requested block index
 193          * to the emulation function */
 194         while (TotalBlocks--)
 195           WriteBlock(CurrentBlock++);
 196 }
 197
 198 void VirtualFAT_ReadBlocks(USB_ClassInfo_MS_Device_t* const MSInterfaceInfo,
 199                            const uint32_t BlockAddress,
 200                            uint16_t TotalBlocks)
 201 {
 202         uint16_t CurrentBlock = (uint16_t)BlockAddress;
 203
 204         /* Emulated FAT is performed per-block, pass each requested block index
 205          * to the emulation function */
 206         while (TotalBlocks--)
 207           ReadBlock(CurrentBlock++);
 208 }
 209