pcdisk.c File Reference

#include <freeldr.h>
#include <debug.h>
#include <pshpack2.h>
#include <poppack.h>

Include dependency graph for pcdisk.c:

Go to the source code of this file.

Classes
struct	I386_DISK_ADDRESS_PACKET
struct	I386_CDROM_SPEC_PACKET
struct	_PC_DISK_DRIVE

Typedefs
typedef struct I386_DISK_ADDRESS_PACKET *	PI386_DISK_ADDRESS_PACKET
typedef struct I386_CDROM_SPEC_PACKET *	PI386_CDROM_SPEC_PACKET
typedef struct _PC_DISK_DRIVE	PC_DISK_DRIVE
typedef struct _PC_DISK_DRIVE *	PPC_DISK_DRIVE

Functions
	DBG_DEFAULT_CHANNEL (DISK)
LONG	DiskReportError (BOOLEAN bShowError)
static PCSTR	DiskGetErrorCodeString (ULONG ErrorCode)
static VOID	DiskError (PCSTR ErrorString, ULONG ErrorCode)
BOOLEAN	DiskResetController (UCHAR DriveNumber)
static BOOLEAN	DiskIsDriveRemovable (UCHAR DriveNumber)
static BOOLEAN	DiskInt13ExtensionsSupported (IN UCHAR DriveNumber)
static BOOLEAN	DiskGetExtendedDriveParameters (IN UCHAR DriveNumber, IN PPC_DISK_DRIVE DiskDrive, OUT PVOID Buffer, IN USHORT BufferSize)
static BOOLEAN	InitDriveGeometry (IN UCHAR DriveNumber, IN PPC_DISK_DRIVE DiskDrive)
static BOOLEAN	PcDiskDriveInit (IN UCHAR DriveNumber, IN OUT PPC_DISK_DRIVE DiskDrive)
static PPC_DISK_DRIVE	PcDiskDriveNumberToDrive (IN UCHAR DriveNumber)
static BOOLEAN	PcDiskReadLogicalSectorsLBA (IN UCHAR DriveNumber, IN ULONGLONG SectorNumber, IN ULONG SectorCount, OUT PVOID Buffer)
static BOOLEAN	PcDiskReadLogicalSectorsCHS (IN UCHAR DriveNumber, IN PPC_DISK_DRIVE DiskDrive, IN ULONGLONG SectorNumber, IN ULONG SectorCount, OUT PVOID Buffer)
BOOLEAN	PcDiskReadLogicalSectors (IN UCHAR DriveNumber, IN ULONGLONG SectorNumber, IN ULONG SectorCount, OUT PVOID Buffer)
BOOLEAN	PcDiskGetDriveGeometry (UCHAR DriveNumber, PGEOMETRY Geometry)
ULONG	PcDiskGetCacheableBlockCount (UCHAR DriveNumber)

Variables
static USHORT	LastDriveNumber = 0xFFFF
static PC_DISK_DRIVE	PcDiskDrive
static LONG	lReportError = 0

Typedef Documentation

PC_DISK_DRIVE

typedef struct _PC_DISK_DRIVE PC_DISK_DRIVE

PI386_CDROM_SPEC_PACKET

typedef struct I386_CDROM_SPEC_PACKET * PI386_CDROM_SPEC_PACKET

PI386_DISK_ADDRESS_PACKET

typedef struct I386_DISK_ADDRESS_PACKET * PI386_DISK_ADDRESS_PACKET

PPC_DISK_DRIVE

typedef struct _PC_DISK_DRIVE * PPC_DISK_DRIVE

Function Documentation

DBG_DEFAULT_CHANNEL()

DBG_DEFAULT_CHANNEL

(

DISK

)

DiskError()

static VOID DiskError ( PCSTR  ErrorString, ULONG  ErrorCode  )

static

Definition at line 163 of file pcdisk.c.

{
    CHAR ErrorCodeString[200];
 
    if (lReportError < 0)
        return;
 
    sprintf(ErrorCodeString, "%s\n\nError Code: 0x%lx\nError: %s",
            ErrorString, ErrorCode, DiskGetErrorCodeString(ErrorCode));
 
    ERR("%s\n", ErrorCodeString);
 
    UiMessageBox(ErrorCodeString);
}

Referenced by PcDiskReadLogicalSectorsCHS(), and PcDiskReadLogicalSectorsLBA().

DiskGetErrorCodeString()

static PCSTR DiskGetErrorCodeString ( ULONG  ErrorCode )

static

Definition at line 128 of file pcdisk.c.

{
    switch (ErrorCode)
    {
    case 0x00:  return "no error";
    case 0x01:  return "bad command passed to driver";
    case 0x02:  return "address mark not found or bad sector";
    case 0x03:  return "diskette write protect error";
    case 0x04:  return "sector not found";
    case 0x05:  return "fixed disk reset failed";
    case 0x06:  return "diskette changed or removed";
    case 0x07:  return "bad fixed disk parameter table";
    case 0x08:  return "DMA overrun";
    case 0x09:  return "DMA access across 64k boundary";
    case 0x0A:  return "bad fixed disk sector flag";
    case 0x0B:  return "bad fixed disk cylinder";
    case 0x0C:  return "unsupported track/invalid media";
    case 0x0D:  return "invalid number of sectors on fixed disk format";
    case 0x0E:  return "fixed disk controlled data address mark detected";
    case 0x0F:  return "fixed disk DMA arbitration level out of range";
    case 0x10:  return "ECC/CRC error on disk read";
    case 0x11:  return "recoverable fixed disk data error, data fixed by ECC";
    case 0x20:  return "controller error (NEC for floppies)";
    case 0x40:  return "seek failure";
    case 0x80:  return "time out, drive not ready";
    case 0xAA:  return "fixed disk drive not ready";
    case 0xBB:  return "fixed disk undefined error";
    case 0xCC:  return "fixed disk write fault on selected drive";
    case 0xE0:  return "fixed disk status error/Error reg = 0";
    case 0xFF:  return "sense operation failed";
 
    default:    return "unknown error code";
    }
}

Referenced by DiskError(), PcDiskReadLogicalSectorsCHS(), and PcDiskReadLogicalSectorsLBA().

DiskGetExtendedDriveParameters()

static BOOLEAN DiskGetExtendedDriveParameters ( IN UCHAR  DriveNumber, IN PPC_DISK_DRIVE  DiskDrive, OUT PVOID  Buffer, IN USHORT  BufferSize  )

static

Definition at line 294 of file pcdisk.c.

{
    REGS RegsIn, RegsOut;
    PUSHORT Ptr = (PUSHORT)(BIOSCALLBUFFER);
 
    TRACE("DiskGetExtendedDriveParameters(0x%x)\n", DriveNumber);
 
    if (!DiskDrive->Int13ExtensionsSupported)
        return FALSE;
 
    /* Initialize transfer buffer */
    *Ptr = BufferSize;
 
    /*
     * BIOS Int 13h, function 48h - Get drive parameters
     * AH = 48h
     * DL = drive (bit 7 set for hard disk)
     * DS:SI = result buffer
     * Return:
     * CF set on error
     * AH = status (07h)
     * CF clear if successful
     * AH = 00h
     * DS:SI -> result buffer
     */
    RegsIn.b.ah = 0x48;
    RegsIn.b.dl = DriveNumber;
    RegsIn.x.ds = BIOSCALLBUFSEGMENT;   // DS:SI -> result buffer
    RegsIn.w.si = BIOSCALLBUFOFFSET;
 
    /* Get drive parameters */
    Int386(0x13, &RegsIn, &RegsOut);
    if (!INT386_SUCCESS(RegsOut))
        return FALSE;
 
    RtlCopyMemory(Buffer, Ptr, BufferSize);
 
#if DBG
    TRACE("size of buffer:                          %x\n", Ptr[0]);
    TRACE("information flags:                       %x\n", Ptr[1]);
    TRACE("number of physical cylinders on drive:   %u\n", *(PULONG)&Ptr[2]);
    TRACE("number of physical heads on drive:       %u\n", *(PULONG)&Ptr[4]);
    TRACE("number of physical sectors per track:    %u\n", *(PULONG)&Ptr[6]);
    TRACE("total number of sectors on drive:        %I64u\n", *(PULONGLONG)&Ptr[8]);
    TRACE("bytes per sector:                        %u\n", Ptr[12]);
    if (Ptr[0] >= 0x1e)
    {
        // Ptr[13]: offset, Ptr[14]: segment
        TRACE("EDD configuration parameters:            %x:%x\n", Ptr[14], Ptr[13]);
        if (Ptr[13] != 0xffff && Ptr[14] != 0xffff)
        {
            PUCHAR SpecPtr = (PUCHAR)(ULONG_PTR)((Ptr[14] << 4) + Ptr[13]);
            TRACE("SpecPtr:                                 %x\n", SpecPtr);
            TRACE("physical I/O port base address:          %x\n", *(PUSHORT)&SpecPtr[0]);
            TRACE("disk-drive control port address:         %x\n", *(PUSHORT)&SpecPtr[2]);
            TRACE("drive flags:                             %x\n", SpecPtr[4]);
            TRACE("proprietary information:                 %x\n", SpecPtr[5]);
            TRACE("IRQ for drive:                           %u\n", SpecPtr[6]);
            TRACE("sector count for multi-sector transfers: %u\n", SpecPtr[7]);
            TRACE("DMA control:                             %x\n", SpecPtr[8]);
            TRACE("programmed I/O control:                  %x\n", SpecPtr[9]);
            TRACE("drive options:                           %x\n", *(PUSHORT)&SpecPtr[10]);
        }
    }
    if (Ptr[0] >= 0x42)
    {
        TRACE("signature:                             %x\n", Ptr[15]);
    }
#endif
 
    return TRUE;
}

Referenced by InitDriveGeometry().

DiskInt13ExtensionsSupported()

static BOOLEAN DiskInt13ExtensionsSupported ( IN UCHAR  DriveNumber )

static

Definition at line 220 of file pcdisk.c.

{
    REGS RegsIn, RegsOut;
 
    /*
     * Some BIOSes report that extended disk access functions are not supported
     * when booting from a CD (e.g. Phoenix BIOS v6.00PG and Insyde BIOS shipping
     * with Intel Macs). Therefore we just return TRUE if we're booting from a CD
     * - we can assume that all El Torito capable BIOSes support INT 13 extensions.
     * We simply detect whether we're booting from CD by checking whether the drive
     * number is >= 0x8A. It's 0x90 on the Insyde BIOS, and 0x9F on most other BIOSes.
     */
    if (DriveNumber >= 0x8A)
        return TRUE;
 
    /*
     * IBM/MS INT 13 Extensions - INSTALLATION CHECK
     * AH = 41h
     * BX = 55AAh
     * DL = drive (80h-FFh)
     * Return:
     * CF set on error (extensions not supported)
     * AH = 01h (invalid function)
     * CF clear if successful
     * BX = AA55h if installed
     * AH = major version of extensions
     * 01h = 1.x
     * 20h = 2.0 / EDD-1.0
     * 21h = 2.1 / EDD-1.1
     * 30h = EDD-3.0
     * AL = internal use
     * CX = API subset support bitmap
     * DH = extension version (v2.0+ ??? -- not present in 1.x)
     *
     * Bitfields for IBM/MS INT 13 Extensions API support bitmap
     * Bit 0, extended disk access functions (AH=42h-44h,47h,48h) supported
     * Bit 1, removable drive controller functions (AH=45h,46h,48h,49h,INT 15/AH=52h) supported
     * Bit 2, enhanced disk drive (EDD) functions (AH=48h,AH=4Eh) supported
     *        extended drive parameter table is valid
     * Bits 3-15 reserved
     */
    RegsIn.b.ah = 0x41;
    RegsIn.w.bx = 0x55AA;
    RegsIn.b.dl = DriveNumber;
 
    /* Reset the disk controller */
    Int386(0x13, &RegsIn, &RegsOut);
    if (!INT386_SUCCESS(RegsOut))
    {
        /* CF set on error (extensions not supported) */
        return FALSE;
    }
 
    if (RegsOut.w.bx != 0xAA55)
    {
        /* BX = AA55h if installed */
        return FALSE;
    }
 
    if (!(RegsOut.w.cx & 0x0001))
    {
        /*
         * CX = API subset support bitmap.
         * Bit 0, extended disk access functions (AH=42h-44h,47h,48h) supported.
         */
        WARN("Suspicious API subset support bitmap 0x%x on device 0x%lx\n",
             RegsOut.w.cx, DriveNumber);
        return FALSE;
    }
 
    return TRUE;
}

Referenced by PcDiskDriveInit().

DiskIsDriveRemovable()

static BOOLEAN DiskIsDriveRemovable ( UCHAR  DriveNumber )

static

Definition at line 205 of file pcdisk.c.

{
    /*
     * Hard disks use drive numbers >= 0x80 . So if the drive number
     * indicates a hard disk then return FALSE.
     * 0x49 is our magic ramdisk drive, so return FALSE for that too.
     */
    if ((DriveNumber >= 0x80) || (DriveNumber == 0x49))
        return FALSE;
 
    /* The drive is a floppy diskette so return TRUE */
    return TRUE;
}

Referenced by PcDiskDriveInit().

DiskReportError()

LONG DiskReportError

(

BOOLEAN

bShowError

)

Definition at line 120 of file pcdisk.c.

{
    /* Set the reference count */
    if (bShowError) ++lReportError;
    else            --lReportError;
    return lReportError;
}

Referenced by EnumerateHarddisks(), and GetHarddiskInformation().

DiskResetController()

BOOLEAN DiskResetController

(

UCHAR

DriveNumber

)

Definition at line 180 of file pcdisk.c.

{
    REGS RegsIn, RegsOut;
 
    WARN("DiskResetController(0x%x) DISK OPERATION FAILED -- RESETTING CONTROLLER\n", DriveNumber);
 
    /*
     * BIOS Int 13h, function 0 - Reset disk system
     * AH = 00h
     * DL = drive (if bit 7 is set both hard disks and floppy disks reset)
     * Return:
     * AH = status
     * CF clear if successful
     * CF set on error
     */
    RegsIn.b.ah = 0x00;
    RegsIn.b.dl = DriveNumber;
 
    /* Reset the disk controller */
    Int386(0x13, &RegsIn, &RegsOut);
 
    return INT386_SUCCESS(RegsOut);
}

Referenced by DetectBiosFloppyPeripheral(), PcDiskReadLogicalSectorsCHS(), and PcDiskReadLogicalSectorsLBA().

InitDriveGeometry()

static BOOLEAN InitDriveGeometry ( IN UCHAR  DriveNumber, IN PPC_DISK_DRIVE  DiskDrive  )

static

Definition at line 372 of file pcdisk.c.

{
    BOOLEAN Success;
    REGS RegsIn, RegsOut;
    ULONG Cylinders;
 
    /* Get the extended geometry first */
    DiskDrive->ExtGeometry.Size = sizeof(DiskDrive->ExtGeometry);
    Success = DiskGetExtendedDriveParameters(DriveNumber, DiskDrive,
                                             &DiskDrive->ExtGeometry,
                                             DiskDrive->ExtGeometry.Size);
    if (!Success)
    {
        /* Failed, zero it out */
        RtlZeroMemory(&DiskDrive->ExtGeometry, sizeof(DiskDrive->ExtGeometry));
    }
    else
    {
        TRACE("DiskGetExtendedDriveParameters(0x%x) returned:\n"
              "Cylinders  : 0x%x\n"
              "Heads      : 0x%x\n"
              "Sects/Track: 0x%x\n"
              "Bytes/Sect : 0x%x\n",
              DriveNumber,
              DiskDrive->ExtGeometry.Cylinders,
              DiskDrive->ExtGeometry.Heads,
              DiskDrive->ExtGeometry.SectorsPerTrack,
              DiskDrive->ExtGeometry.BytesPerSector);
    }
 
    /* Now try the legacy geometry */
    RtlZeroMemory(&DiskDrive->Geometry, sizeof(DiskDrive->Geometry));
 
    /*
     * BIOS Int 13h, function 08h - Get drive parameters
     * AH = 08h
     * DL = drive (bit 7 set for hard disk)
     * ES:DI = 0000h:0000h to guard against BIOS bugs
     * Return:
     * CF set on error
     * AH = status (07h)
     * CF clear if successful
     * AH = 00h
     * AL = 00h on at least some BIOSes
     * BL = drive type (AT/PS2 floppies only)
     * CH = low eight bits of maximum cylinder number
     * CL = maximum sector number (bits 5-0)
     *      high two bits of maximum cylinder number (bits 7-6)
     * DH = maximum head number
     * DL = number of drives
     * ES:DI -> drive parameter table (floppies only)
     */
    RegsIn.b.ah = 0x08;
    RegsIn.b.dl = DriveNumber;
    RegsIn.w.es = 0x0000;
    RegsIn.w.di = 0x0000;
 
    /* Get drive parameters */
    Int386(0x13, &RegsIn, &RegsOut);
    if (!INT386_SUCCESS(RegsOut))
    {
        /* We failed, return the result of the previous call (extended geometry) */
        return Success;
    }
    /* OR it with the old result, so that we return TRUE whenever either call succeeded */
    Success |= TRUE;
 
    Cylinders = (RegsOut.b.cl & 0xC0) << 2;
    Cylinders += RegsOut.b.ch;
    Cylinders++;
    DiskDrive->Geometry.Cylinders = Cylinders;
    DiskDrive->Geometry.Heads = RegsOut.b.dh + 1;
    DiskDrive->Geometry.SectorsPerTrack = RegsOut.b.cl & 0x3F;
    DiskDrive->Geometry.BytesPerSector = 512;   /* Just assume 512 bytes per sector */
 
    DiskDrive->Geometry.Sectors = (ULONGLONG)DiskDrive->Geometry.Cylinders *
                                             DiskDrive->Geometry.Heads *
                                             DiskDrive->Geometry.SectorsPerTrack;
 
    TRACE("Regular Int13h(0x%x) returned:\n"
          "Cylinders  : 0x%x\n"
          "Heads      : 0x%x\n"
          "Sects/Track: 0x%x (original 0x%x)\n"
          "Bytes/Sect : 0x%x\n",
          DriveNumber,
          DiskDrive->Geometry.Cylinders,
          DiskDrive->Geometry.Heads,
          DiskDrive->Geometry.SectorsPerTrack, RegsOut.b.cl,
          DiskDrive->Geometry.BytesPerSector);
 
    return Success;
}

Referenced by PcDiskDriveInit().

PcDiskDriveInit()

static BOOLEAN PcDiskDriveInit ( IN UCHAR  DriveNumber, IN OUT PPC_DISK_DRIVE  DiskDrive  )

static

Definition at line 468 of file pcdisk.c.

{
    DiskDrive->IsRemovable = DiskIsDriveRemovable(DriveNumber);
 
    /*
     * Check to see if it is a fixed disk drive.
     * If so then check to see if INT 13h extensions work.
     * If they do then use them, otherwise default back to BIOS calls.
     */
    DiskDrive->Int13ExtensionsSupported = DiskInt13ExtensionsSupported(DriveNumber);
 
    if (!InitDriveGeometry(DriveNumber, DiskDrive))
        return FALSE;
 
    TRACE("\n"
          "DriveNumber: 0x%x\n"
          "IsRemovable              = %s\n"
          "Int13ExtensionsSupported = %s\n",
          DriveNumber,
          DiskDrive->IsRemovable ? "TRUE" : "FALSE",
          DiskDrive->Int13ExtensionsSupported ? "TRUE" : "FALSE");
 
    return TRUE;
}

Referenced by PcDiskDriveNumberToDrive().

PcDiskDriveNumberToDrive()

static PPC_DISK_DRIVE PcDiskDriveNumberToDrive ( IN UCHAR  DriveNumber )

inlinestatic

Definition at line 497 of file pcdisk.c.

{
#ifdef CACHE_MULTI_DRIVES
    PPC_DISK_DRIVE DiskDrive;
 
    ASSERT((0 <= DriveNumber) && (DriveNumber < RTL_NUMBER_OF(PcDiskDrive)));
 
    /* Retrieve a slot */
    DiskDrive = &PcDiskDrive[DriveNumber];
 
    /* If the drive has not been initialized before... */
    if (!DiskDrive->Initialized)
    {
        /* ... try to initialize it now. */
        if (!PcDiskDriveInit(DriveNumber, DiskDrive))
        {
            /*
             * If we failed, there is no drive at this number
             * and flag it as such (set its high bit).
             */
            DiskDrive->Initialized |= 0x80;
            return NULL;
        }
        DiskDrive->Initialized = TRUE;
    }
    else if (DiskDrive->Initialized & 0x80)
    {
        /*
         * The disk failed to be initialized previously, reset its flag to give
         * it chance to be initialized again later, but just fail for the moment.
         */
        DiskDrive->Initialized = FALSE;
        return NULL;
    }
 
    return DiskDrive;
#else
    static PC_DISK_DRIVE NewDiskDrive;
 
    ASSERT((0 <= DriveNumber) && (DriveNumber <= 0xFF));
 
    /* Update cached information */
 
    /* If the drive has not been accessed last before... */
    if ((USHORT)DriveNumber != LastDriveNumber)
    {
        /* ... try to (re-)initialize and cache it now. */
        RtlZeroMemory(&NewDiskDrive, sizeof(NewDiskDrive));
        if (!PcDiskDriveInit(DriveNumber, &NewDiskDrive))
        {
            /*
             * If we failed, there is no drive at this number.
             * Keep the last-accessed valid drive cached.
             */
            return NULL;
        }
        /* We succeeded, cache the drive data */
        PcDiskDrive = NewDiskDrive;
        LastDriveNumber = (USHORT)DriveNumber;
    }
 
    return &PcDiskDrive;
#endif /* CACHE_MULTI_DRIVES */
}

Referenced by PcDiskGetCacheableBlockCount(), PcDiskGetDriveGeometry(), and PcDiskReadLogicalSectors().

PcDiskGetCacheableBlockCount()

ULONG PcDiskGetCacheableBlockCount

(

UCHAR

DriveNumber

)

Definition at line 815 of file pcdisk.c.

{
    PPC_DISK_DRIVE DiskDrive;
 
    DiskDrive = PcDiskDriveNumberToDrive(DriveNumber);
    if (!DiskDrive)
        return 1; // Unknown count.
 
    /*
     * If LBA is supported then the block size will be 64 sectors (32k).
     * If not then the block size is the size of one track.
     */
    if (DiskDrive->Int13ExtensionsSupported)
        return 64;
    else
        return DiskDrive->Geometry.SectorsPerTrack;
}

Referenced by MachInit().

PcDiskGetDriveGeometry()

BOOLEAN PcDiskGetDriveGeometry	(	UCHAR	DriveNumber,
		PGEOMETRY	Geometry
	)

Definition at line 785 of file pcdisk.c.

{
    PPC_DISK_DRIVE DiskDrive;
 
    TRACE("PcDiskGetDriveGeometry(0x%x)\n", DriveNumber);
 
    DiskDrive = PcDiskDriveNumberToDrive(DriveNumber);
    if (!DiskDrive)
        return FALSE;
 
    /* Try to get the extended geometry first */
    if (DiskDrive->ExtGeometry.Size == sizeof(DiskDrive->ExtGeometry))
    {
        /* Extended geometry has been initialized, return it */
        Geometry->Cylinders = DiskDrive->ExtGeometry.Cylinders;
        Geometry->Heads = DiskDrive->ExtGeometry.Heads;
        Geometry->SectorsPerTrack = DiskDrive->ExtGeometry.SectorsPerTrack;
        Geometry->BytesPerSector = DiskDrive->ExtGeometry.BytesPerSector;
        Geometry->Sectors = DiskDrive->ExtGeometry.Sectors;
    }
    else
    /* Fall back to legacy BIOS geometry */
    {
        *Geometry = DiskDrive->Geometry;
    }
 
    return TRUE;
}

Referenced by MachInit(), and PcGetHarddiskConfigurationData().

PcDiskReadLogicalSectors()

BOOLEAN PcDiskReadLogicalSectors	(	IN UCHAR	DriveNumber,
		IN ULONGLONG	SectorNumber,
		IN ULONG	SectorCount,
		OUT PVOID	Buffer
	)

Definition at line 745 of file pcdisk.c.

{
    PPC_DISK_DRIVE DiskDrive;
 
    TRACE("PcDiskReadLogicalSectors() DriveNumber: 0x%x SectorNumber: %I64d SectorCount: %d Buffer: 0x%x\n",
          DriveNumber, SectorNumber, SectorCount, Buffer);
 
    /* 16-bit BIOS addressing limitation */
    ASSERT(((ULONG_PTR)Buffer) <= 0xFFFFF);
 
    DiskDrive = PcDiskDriveNumberToDrive(DriveNumber);
    if (!DiskDrive)
        return FALSE;
 
    if ((DriveNumber >= 0x80) && DiskDrive->Int13ExtensionsSupported)
    {
        /* LBA is easy, nothing to calculate. Just do the read. */
        TRACE("--> Using LBA\n");
        return PcDiskReadLogicalSectorsLBA(DriveNumber, SectorNumber, SectorCount, Buffer);
    }
    else
    {
        /* LBA is not supported, default to CHS */
        TRACE("--> Using CHS\n");
        return PcDiskReadLogicalSectorsCHS(DriveNumber, DiskDrive, SectorNumber, SectorCount, Buffer);
    }
}

Referenced by MachInit().

PcDiskReadLogicalSectorsCHS()

static BOOLEAN PcDiskReadLogicalSectorsCHS ( IN UCHAR  DriveNumber, IN PPC_DISK_DRIVE  DiskDrive, IN ULONGLONG  SectorNumber, IN ULONG  SectorCount, OUT PVOID  Buffer  )

static

Definition at line 627 of file pcdisk.c.

{
    UCHAR PhysicalSector;
    UCHAR PhysicalHead;
    ULONG PhysicalTrack;
    GEOMETRY DriveGeometry;
    ULONG NumberOfSectorsToRead;
    REGS RegsIn, RegsOut;
    ULONG RetryCount;
 
    DriveGeometry = DiskDrive->Geometry;
    if (DriveGeometry.SectorsPerTrack == 0 || DriveGeometry.Heads == 0)
        return FALSE;
 
    while (SectorCount > 0)
    {
        /*
         * Calculate the physical disk offsets.
         * Note: DriveGeometry.SectorsPerTrack < 64
         */
        PhysicalSector = 1 + (UCHAR)(SectorNumber % DriveGeometry.SectorsPerTrack);
        PhysicalHead = (UCHAR)((SectorNumber / DriveGeometry.SectorsPerTrack) % DriveGeometry.Heads);
        PhysicalTrack = (ULONG)((SectorNumber / DriveGeometry.SectorsPerTrack) / DriveGeometry.Heads);
 
        /* Calculate how many sectors we need to read this round */
        if (PhysicalSector > 1)
        {
            NumberOfSectorsToRead = min(SectorCount,
                                        (DriveGeometry.SectorsPerTrack - (PhysicalSector - 1)));
        }
        else
        {
            NumberOfSectorsToRead = min(SectorCount, DriveGeometry.SectorsPerTrack);
        }
 
        /* Make sure the read is within the geometry boundaries */
        if ((PhysicalHead >= DriveGeometry.Heads) ||
            (PhysicalTrack >= DriveGeometry.Cylinders) ||
            ((NumberOfSectorsToRead + PhysicalSector) > (DriveGeometry.SectorsPerTrack + 1)) ||
            (PhysicalSector > DriveGeometry.SectorsPerTrack))
        {
            DiskError("Disk read exceeds drive geometry limits.", 0);
            return FALSE;
        }
 
        /*
         * BIOS Int 13h, function 2 - Read Disk Sectors
         * AH = 02h
         * AL = number of sectors to read (must be nonzero)
         * CH = low eight bits of cylinder number
         * CL = sector number 1-63 (bits 0-5)
         *      high two bits of cylinder (bits 6-7, hard disk only)
         * DH = head number
         * DL = drive number (bit 7 set for hard disk)
         * ES:BX -> data buffer
         * Return:
         * CF set on error
         * if AH = 11h (corrected ECC error), AL = burst length
         * CF clear if successful
         * AH = status
         * AL = number of sectors transferred
         *  (only valid if CF set for some BIOSes)
         */
        RegsIn.b.ah = 0x02;
        RegsIn.b.al = (UCHAR)NumberOfSectorsToRead;
        RegsIn.b.ch = (PhysicalTrack & 0xFF);
        RegsIn.b.cl = (UCHAR)(PhysicalSector + ((PhysicalTrack & 0x300) >> 2));
        RegsIn.b.dh = PhysicalHead;
        RegsIn.b.dl = DriveNumber;
        RegsIn.w.es = (USHORT)(((ULONG_PTR)Buffer) >> 4);
        RegsIn.w.bx = ((ULONG_PTR)Buffer) & 0x0F;
 
        /* Perform the read. Retry 3 times. */
        for (RetryCount = 0; RetryCount < 3; ++RetryCount)
        {
            Int386(0x13, &RegsIn, &RegsOut);
 
            /* If it worked, or if it was a corrected ECC error
             * and the data is still good, break out */
            if (INT386_SUCCESS(RegsOut) || (RegsOut.b.ah == 0x11))
                break;
 
            /* It failed, do the next retry */
            DiskResetController(DriveNumber);
        }
 
        /* If we retried 3 times then fail */
        if (RetryCount >= 3)
        {
            DiskError("Disk Read Failed in CHS mode, after retrying 3 times", RegsOut.b.ah);
            ERR("Disk Read Failed in CHS mode, after retrying 3 times: %x (%s) (DriveNumber: 0x%x SectorNumber: %I64d SectorCount: %d)\n",
                RegsOut.b.ah, DiskGetErrorCodeString(RegsOut.b.ah),
                DriveNumber, SectorNumber, SectorCount);
            return FALSE;
        }
 
        /*
         * I have learned that not all BIOSes return
         * the sector read count in the AL register (at least mine doesn't)
         * even if the sectors were read correctly. So instead
         * of checking the sector read count we will rely solely
         * on the carry flag being set on error.
         */
 
        Buffer = (PVOID)((ULONG_PTR)Buffer + (NumberOfSectorsToRead * DriveGeometry.BytesPerSector));
        SectorCount -= NumberOfSectorsToRead;
        SectorNumber += NumberOfSectorsToRead;
    }
 
    return TRUE;
}

Referenced by PcDiskReadLogicalSectors().

PcDiskReadLogicalSectorsLBA()

static BOOLEAN PcDiskReadLogicalSectorsLBA ( IN UCHAR  DriveNumber, IN ULONGLONG  SectorNumber, IN ULONG  SectorCount, OUT PVOID  Buffer  )

static

Definition at line 563 of file pcdisk.c.

{
    REGS RegsIn, RegsOut;
    ULONG RetryCount;
    PI386_DISK_ADDRESS_PACKET Packet = (PI386_DISK_ADDRESS_PACKET)(BIOSCALLBUFFER);
 
    /* Setup disk address packet */
    RtlZeroMemory(Packet, sizeof(*Packet));
    Packet->PacketSize = sizeof(*Packet);
    Packet->Reserved = 0;
    // Packet->LBABlockCount set in the loop.
    Packet->TransferBufferOffset = ((ULONG_PTR)Buffer) & 0x0F;
    Packet->TransferBufferSegment = (USHORT)(((ULONG_PTR)Buffer) >> 4);
    Packet->LBAStartBlock = SectorNumber;
 
    /*
     * BIOS Int 13h, function 42h - IBM/MS INT 13 Extensions - EXTENDED READ
     * Return:
     * CF clear if successful
     * AH = 00h
     * CF set on error
     * AH = error code
     * Disk address packet's block count field set to the
     * number of blocks successfully transferred.
     */
    RegsIn.b.ah = 0x42;
    RegsIn.b.dl = DriveNumber;          // Drive number in DL (0 - floppy, 0x80 - harddisk)
    RegsIn.x.ds = BIOSCALLBUFSEGMENT;   // DS:SI -> disk address packet
    RegsIn.w.si = BIOSCALLBUFOFFSET;
 
    /* Retry 3 times */
    for (RetryCount = 0; RetryCount < 3; ++RetryCount)
    {
        /* Restore the number of blocks to transfer, since it gets reset
         * on failure with the number of blocks that were successfully
         * transferred (and which could be zero). */
        Packet->LBABlockCount = (USHORT)SectorCount;
        ASSERT(Packet->LBABlockCount == SectorCount);
 
        Int386(0x13, &RegsIn, &RegsOut);
 
        /* If it worked, or if it was a corrected ECC error
         * and the data is still good, return success */
        if (INT386_SUCCESS(RegsOut) || (RegsOut.b.ah == 0x11))
            return TRUE;
 
        /* It failed, do the next retry */
        DiskResetController(DriveNumber);
    }
 
    /* If we get here then the read failed */
    DiskError("Disk Read Failed in LBA mode", RegsOut.b.ah);
    ERR("Disk Read Failed in LBA mode: %x (%s) (DriveNumber: 0x%x SectorNumber: %I64d SectorCount: %d)\n",
        RegsOut.b.ah, DiskGetErrorCodeString(RegsOut.b.ah),
        DriveNumber, SectorNumber, SectorCount);
 
    return FALSE;
}

Referenced by PcDiskReadLogicalSectors().

Variable Documentation

LastDriveNumber

USHORT LastDriveNumber = 0xFFFF

static

Definition at line 112 of file pcdisk.c.

Referenced by PcDiskDriveNumberToDrive().

lReportError

LONG lReportError = 0

static

Definition at line 118 of file pcdisk.c.

Referenced by DiskError(), and DiskReportError().

PcDiskDrive

PC_DISK_DRIVE PcDiskDrive

static

Definition at line 113 of file pcdisk.c.

Referenced by PcDiskDriveNumberToDrive().