freeldr/freeldr/disk/disk.c

   1 /*
   2  *  FreeLoader
   3  *  Copyright (C) 1998-2002  Brian Palmer  <brianp@sginet.com>
   4  *
   5  *  This program is free software; you can redistribute it and/or modify
   6  *  it under the terms of the GNU General Public License as published by
   7  *  the Free Software Foundation; either version 2 of the License, or
   8  *  (at your option) any later version.
   9  *
  10  *  This program is distributed in the hope that it will be useful,
  11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  *  GNU General Public License for more details.
  14  *
  15  *  You should have received a copy of the GNU General Public License
  16  *  along with this program; if not, write to the Free Software
  17  *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  18  */
  19
  20 #include <freeldr.h>
  21 #include <disk.h>
  22 #include <fs.h>
  23 #include <rtl.h>
  24 #include <ui.h>
  25 #include <arch.h>
  26 #include <debug.h>
  27
  28
  29 /////////////////////////////////////////////////////////////////////////////////////////////
  30 // FUNCTIONS
  31 /////////////////////////////////////////////////////////////////////////////////////////////
  32
  33 VOID DiskError(PUCHAR ErrorString)
  34 {
  35         UCHAR   ErrorCodeString[80];
  36
  37         sprintf(ErrorCodeString, "%s\nError Code: 0x%x", ErrorString, BiosInt13GetLastErrorCode());
  38
  39         DbgPrint((DPRINT_DISK, "%s\n", ErrorCodeString));
  40
  41         UiMessageBox(ErrorCodeString);
  42 }
  43
  44 BOOL DiskReadLogicalSectors(U32 DriveNumber, U32 SectorNumber, U32 SectorCount, PVOID Buffer)
  45 {
  46         U32                     PhysicalSector;
  47         U32                     PhysicalHead;
  48         U32                     PhysicalTrack;
  49         GEOMETRY        DriveGeometry;
  50         U32                     NumberOfSectorsToRead;
  51
  52         DbgPrint((DPRINT_DISK, "ReadLogicalSectors() DriveNumber: 0x%x SectorNumber: %d SectorCount: %d Buffer: 0x%x\n", DriveNumber, SectorNumber, SectorCount, Buffer));
  53
  54         //
  55         // Check to see if it is a fixed disk drive
  56         // If so then check to see if Int13 extensions work
  57         // If they do then use them, otherwise default back to BIOS calls
  58         //
  59         if ((DriveNumber >= 0x80) && (IsSetupLdr || BiosInt13ExtensionsSupported(DriveNumber)))
  60         {
  61                 DbgPrint((DPRINT_DISK, "Using Int 13 Extensions for read. BiosInt13ExtensionsSupported(%d) = %s\n", DriveNumber, BiosInt13ExtensionsSupported(DriveNumber) ? "TRUE" : "FALSE"));
  62
  63                 //
  64                 // LBA is easy, nothing to calculate
  65                 // Just do the read
  66                 //
  67                 if (!BiosInt13ReadExtended(DriveNumber, SectorNumber, SectorCount, Buffer))
  68                 {
  69                         DiskError("Disk read error.");
  70                         return FALSE;
  71                 }
  72         }
  73         else
  74         {
  75                 //
  76                 // Get the drive geometry
  77                 //
  78                 if (!DiskGetDriveGeometry(DriveNumber, &DriveGeometry))
  79                 {
  80                         return FALSE;
  81                 }
  82
  83                 while (SectorCount)
  84                 {
  85
  86                         //
  87                         // Calculate the physical disk offsets
  88                         //
  89                         PhysicalSector = 1 + (SectorNumber % DriveGeometry.Sectors);
  90                         PhysicalHead = (SectorNumber / DriveGeometry.Sectors) % DriveGeometry.Heads;
  91                         PhysicalTrack = (SectorNumber / DriveGeometry.Sectors) / DriveGeometry.Heads;
  92
  93                         //
  94                         // Calculate how many sectors we are supposed to read
  95                         //
  96                         if (PhysicalSector > 1)
  97                         {
  98                                 if (SectorCount >= (DriveGeometry.Sectors - (PhysicalSector - 1)))
  99                                         NumberOfSectorsToRead = (DriveGeometry.Sectors - (PhysicalSector - 1));
 100                                 else
 101                                         NumberOfSectorsToRead = SectorCount;
 102                         }
 103                         else
 104                         {
 105                                 if (SectorCount >= DriveGeometry.Sectors)
 106                                         NumberOfSectorsToRead = DriveGeometry.Sectors;
 107                                 else
 108                                         NumberOfSectorsToRead = SectorCount;
 109                         }
 110
 111                         DbgPrint((DPRINT_DISK, "Calling BiosInt13Read() with PhysicalHead: %d\n", PhysicalHead));
 112                         DbgPrint((DPRINT_DISK, "Calling BiosInt13Read() with PhysicalTrack: %d\n", PhysicalTrack));
 113                         DbgPrint((DPRINT_DISK, "Calling BiosInt13Read() with PhysicalSector: %d\n", PhysicalSector));
 114                         DbgPrint((DPRINT_DISK, "Calling BiosInt13Read() with NumberOfSectorsToRead: %d\n", NumberOfSectorsToRead));
 115
 116                         //
 117                         // Make sure the read is within the geometry boundaries
 118                         //
 119                         if ((PhysicalHead >= DriveGeometry.Heads) ||
 120                                 (PhysicalTrack >= DriveGeometry.Cylinders) ||
 121                                 ((NumberOfSectorsToRead + PhysicalSector) > (DriveGeometry.Sectors + 1)) ||
 122                                 (PhysicalSector > DriveGeometry.Sectors))
 123                         {
 124                                 DiskError("Disk read exceeds drive geometry limits.");
 125                                 return FALSE;
 126                         }
 127
 128                         //
 129                         // Perform the read
 130                         //
 131                         if (!BiosInt13Read(DriveNumber, PhysicalHead, PhysicalTrack, PhysicalSector, NumberOfSectorsToRead, Buffer))
 132                         {
 133                                 DiskError("Disk read error.");
 134                                 return FALSE;
 135                         }
 136
 137                         Buffer += (NumberOfSectorsToRead * DriveGeometry.BytesPerSector);
 138                         SectorCount -= NumberOfSectorsToRead;
 139                         SectorNumber += NumberOfSectorsToRead;
 140                 }
 141         }
 142
 143         return TRUE;
 144 }