source: xtideuniversalbios/trunk/XTIDE_Universal_BIOS/Src/VariablesAndDPTs/CreateDPT.asm@ 540

; Project name  :   XTIDE Universal BIOS
; Description   :   Functions for creating Disk Parameter Table.

;
; XTIDE Universal BIOS and Associated Tools
; Copyright (C) 2009-2010 by Tomi Tilli, 2011-2013 by XTIDE Universal BIOS Team.
;
; This program is free software; you can redistribute it and/or modify
; it under the terms of the GNU General Public License as published by
; the Free Software Foundation; either version 2 of the License, or
; (at your option) any later version.
;
; This program is distributed in the hope that it will be useful,
; but WITHOUT ANY WARRANTY; without even the implied warranty of
; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
; GNU General Public License for more details.
; Visit http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
;

; Section containing code
SECTION .text

;--------------------------------------------------------------------
; Creates new Disk Parameter Table for detected hard disk.
; Drive is then fully accessible using any BIOS function.
;
; CreateDPT_FromAtaInformation
;   Parameters:
;       BH:     Drive Select byte for Drive and Head Register
;       DX:     Autodetected port (for devices that support autodetection)
;       ES:SI:  Ptr to 512-byte ATA information read from the drive
;       CS:BP:  Ptr to IDEVARS for the controller
;       DS:     RAMVARS segment
;       ES:     BDA Segment
;   Returns:
;       DS:DI:  Ptr to Disk Parameter Table (if successful)
;       CF:     Cleared if DPT created successfully
;               Set if any error
;   Corrupts registers:
;       AX, BX, CX, DH
;--------------------------------------------------------------------
CreateDPT_FromAtaInformation:
    call    FindDPT_ForNewDriveToDSDI
    ; Fall to .InitializeDPT

;--------------------------------------------------------------------
; .InitializeDPT
;   Parameters:
;       BH:     Drive Select byte for Drive and Head Register
;       DX:     Autodetected port (for devices that support autodetection)
;       DS:DI:  Ptr to Disk Parameter Table
;       CS:BP:  Ptr to IDEVARS for the controller
;   Returns:
;       Nothing
;   Corrupts registers:
;       AX
;--------------------------------------------------------------------
.InitializeDPT:
    call    CreateDPT_StoreIdevarsOffsetAndBasePortFromCSBPtoDPTinDSDI
    ; Fall to .StoreDriveSelectAndDriveControlByte

;--------------------------------------------------------------------
; .StoreDriveSelectAndDriveControlByte
;   Parameters:
;       BH:     Drive Select byte for Drive and Head Register
;       DS:DI:  Ptr to Disk Parameter Table
;       ES:SI:  Ptr to 512-byte ATA information read from the drive
;       CS:BP:  Ptr to IDEVARS for the controller
;   Returns:
;       Nothing
;   Corrupts registers:
;       AX
;--------------------------------------------------------------------
.StoreDriveSelectAndDriveControlByte:
    mov     al, bh
    and     ax, BYTE FLG_DRVNHEAD_DRV       ; AL now has Master/Slave bit
%ifdef MODULE_IRQ
    cmp     [cs:bp+IDEVARS.bIRQ], ah        ; Interrupts enabled?
    jz      SHORT .StoreFlags               ;  If not, do not set interrupt flag
    or      al, FLGL_DPT_ENABLE_IRQ
.StoreFlags:
%endif
    mov     [di+DPT.wFlags], ax
    ; Fall to .StoreCHSparametersAndAddressingMode

;--------------------------------------------------------------------
; .StoreCHSparametersAndAddressingMode
;   Parameters:
;       DS:DI:  Ptr to Disk Parameter Table
;       ES:SI:  Ptr to 512-byte ATA information read from the drive
;       CS:BP:  Ptr to IDEVARS for the controller
;   Returns:
;       Nothing
;   Corrupts registers:
;       AX, BX, CX, DX
;--------------------------------------------------------------------
.StoreCHSparametersAndAddressingMode:
    ; Check if CHS defined in ROMVARS
    call    GetUserDefinedCapacityToBXAXandFlagsToCXandModeToDXfromROMVARS
    test    cl, FLG_DRVPARAMS_USERCHS
    jz      SHORT .AutodetectPCHSvalues

    ; Translate P-CHS to L-CHS
    call    AtaGeometry_GetLCHStoAXBLBHfromPCHSinAXBLBHandTranslateModeInDX
    jmp     SHORT .StoreLCHStoDPT
.AutodetectPCHSvalues:
    call    AtaGeometry_GetLCHStoAXBLBHfromAtaInfoInESSIandTranslateModeInDX

.StoreLCHStoDPT:
    eSHL_IM dl, TRANSLATEMODE_FIELD_POSITION
    or      cl, dl
    or      [di+DPT.bFlagsLow], cl      ; Shift count and addressing mode
    mov     [di+DPT.wLchsCylinders], ax
    mov     [di+DPT.wLchsHeadsAndSectors], bx

    ; Store P-CHS to DPT
    call    AtaGeometry_GetPCHStoAXBLBHfromAtaInfoInESSI
    mov     [di+DPT.bPchsHeads], bl
%ifdef MODULE_EBIOS
    mov     [di+DPT.bPchsSectorsPerTrack], bh

; This is what Award BIOS from 1997 Pentium motherboard does. I can't think
; of any good reason to do the same but let's keep this here just in case,
; at least for a while.
%if 0
%ifdef RESERVE_DIAGNOSTIC_CYLINDER
    ; Do not store P-Cylinders, instead calculate it from L-CHS total sector count.
    ; Read AH=48h_GetExtendedDriveParameters.asm for more info.
    xchg    ax, bx
    mul     ah
    push    ax                          ; P-Heads * P-Sectors per track
    call    AH15h_GetSectorCountToBXDXAX
    pop     bx
    div     bx                          ; AX = Calculated cylinders
%endif ; RESERVE_DIAGNOSTIC_CYLINDER
%endif ; 0

    mov     [di+DPT.wPchsCylinders], ax
    ; Fall to .StoreNumberOfLbaSectors

;--------------------------------------------------------------------
; .StoreNumberOfLbaSectors
;   Parameters:
;       DS:DI:  Ptr to Disk Parameter Table
;       ES:SI:  Ptr to 512-byte ATA information read from the drive
;       CS:BP:  Ptr to IDEVARS for the controller
;   Returns:
;       Nothing
;   Corrupts registers:
;       AX, BX, CX, DX
;--------------------------------------------------------------------
    ; Check if LBA supported
    test    BYTE [es:si+ATA1.wCaps+1], A1_wCaps_LBA>>8
    jz      SHORT .NoLbaSupportedSoNoEBIOS

    ; Store LBA 28/48 total sector count
    call    AtaGeometry_GetLbaSectorCountToBXDXAXfromAtaInfoInESSI
    call    StoreLba48AddressingFromCLandTotalSectorCountFromBXDXAX

    ; If we have 15,482,880 or less sectors, we multiply P-CHS values
    ; and use that as total sector count.
    ; Read AH=48h_GetExtendedDriveParameters.asm for more info.
    sub     ax, 4001h
    sbb     dx, 0ECh
    sbb     bx, BYTE 0
    jnc     SHORT .NoNeedToUseCHSsectorCount    ; More than EC4000h

    mov     al, [di+DPT.bPchsHeads]
    mul     BYTE [di+DPT.bPchsSectorsPerTrack]
    mul     WORD [di+DPT.wPchsCylinders]
    xor     bx, bx
    call    StoreLba48AddressingFromCLandTotalSectorCountFromBXDXAX

    ; Load user defined LBA
.NoNeedToUseCHSsectorCount:
    call    GetUserDefinedCapacityToBXAXandFlagsToCXandModeToDXfromROMVARS
    test    cl, FLG_DRVPARAMS_USERLBA
    jz      SHORT .KeepTotalSectorsFromAtaID

    ; Compare user defined and ATA-ID sector count and select smaller
    mov     dx, bx
    xor     bx, bx      ; User defined LBA now in BX:DX:AX
    cmp     bx, [di+DPT.twLbaSectors+4]
    jb      SHORT .StoreUserDefinedSectorCountToDPT
    cmp     dx, [di+DPT.twLbaSectors+2]
    jb      SHORT .StoreUserDefinedSectorCountToDPT
    ja      SHORT .KeepTotalSectorsFromAtaID
    cmp     ax, [di+DPT.twLbaSectors]
    jae     SHORT .KeepTotalSectorsFromAtaID
.StoreUserDefinedSectorCountToDPT:
    ; CL bit FLGL_DPT_LBA48 is clear at this point
    call    StoreLba48AddressingFromCLandTotalSectorCountFromBXDXAX

.KeepTotalSectorsFromAtaID:
.NoLbaSupportedSoNoEBIOS:
%endif ; MODULE_EBIOS
    ; Fall to .StoreBlockMode

;--------------------------------------------------------------------
; .StoreBlockMode
;   Parameters:
;       DS:DI:  Ptr to Disk Parameter Table
;       ES:SI:  Ptr to 512-byte ATA information read from the drive
;       CS:BP:  Ptr to IDEVARS for the controller
;   Returns:
;       Nothing
;   Corrupts registers:
;       Nothing
;--------------------------------------------------------------------
.StoreBlockMode:
    cmp     BYTE [es:si+ATA1.bBlckSize], 1  ; Max block size in sectors
    jbe     SHORT .BlockModeTransfersNotSupported
    or      BYTE [di+DPT.bFlagsHigh], FLGH_DPT_BLOCK_MODE_SUPPORTED
.BlockModeTransfersNotSupported:
    ; Fall to .StoreDeviceSpecificParameters

;--------------------------------------------------------------------
; .StoreDeviceSpecificParameters
;   Parameters:
;       DS:DI:  Ptr to Disk Parameter Table
;       ES:SI:  Ptr to 512-byte ATA information read from the drive
;       CS:BP:  Ptr to IDEVARS for the controller
;   Returns:
;       Nothing
;   Corrupts registers:
;       AX, BX, CX, DX
;--------------------------------------------------------------------
.StoreDeviceSpecificParameters:
    call    Device_FinalizeDPT

;----------------------------------------------------------------------
; Update drive counts (hard and floppy)
;----------------------------------------------------------------------

%ifdef MODULE_SERIAL_FLOPPY
;
; These two instructions serve two purposes:
; 1. If the drive is a floppy drive (CF set), then we effectively increment the counter.
; 2. If this is a hard disk, and there have been any floppy drives previously added, then the hard disk is
;    effectively discarded.  This is more of a safety check then code that should ever normally be hit (see below).
;    Since the floppy DPT's come after the hard disk DPT's, without expensive (code size) code to relocate a DPT,
;    this was necessary.  Now, this situation shouldn't happen in normal operation, for a couple of reasons:
;       A. xtidecfg always puts configured serial ports at the end of the IDEVARS list
;       B. the auto serial code is always executed last
;       C. the serial server always returns floppy drives last
;
    adc     byte [RAMVARS.xlateVars+XLATEVARS.bFlopCreateCnt], 0
    jnz     .AllDone
%else
;
; Even without floppy support enabled, we shouldn't try to mount a floppy image as a hard disk, which
; could lead to unpredictable results since no MBR will be present, etc.  The server doesn't know that
; floppies are supported, so it is important to still fail here if a floppy is seen during the drive scan.
;
    jc      .AllDone
%endif

    inc     BYTE [RAMVARS.bDrvCnt]      ; Increment drive count to RAMVARS

.AllDone:
    clc
    ret


;--------------------------------------------------------------------
; CreateDPT_StoreIdevarsOffsetAndBasePortFromCSBPtoDPTinDSDI
;   Parameters:
;       DX:     Autodetected port (for devices that support autodetection)
;       DS:DI:  Ptr to Disk Parameter Table
;       CS:BP:  Ptr to IDEVARS for the controller
;   Returns:
;       Nothing
;   Corrupts registers:
;       AX
;--------------------------------------------------------------------
CreateDPT_StoreIdevarsOffsetAndBasePortFromCSBPtoDPTinDSDI:
    mov     [di+DPT.bIdevarsOffset], bp     ; IDEVARS must start in first 256 bytes of ROM

%ifdef MODULE_8BIT_IDE_ADVANCED
    call    DetectDrives_DoesIdevarsInCSBPbelongToXTCF
    jne     SHORT .DeviceUsesPortSpecifiedInIDEVARS
    mov     [di+DPT.wBasePort], dx
    ret
.DeviceUsesPortSpecifiedInIDEVARS:
%endif ; MODULE_8BIT_IDE_ADVANCED

    mov     ax, [cs:bp+IDEVARS.wBasePort]
    mov     [di+DPT.wBasePort], ax
    ret


;--------------------------------------------------------------------
; GetUserDefinedCapacityToBXAXandFlagsToCXandModeToDXfromROMVARS
;   Parameters:
;       DS:DI:      Ptr to Disk Parameter Table
;   Returns:
;       AX:         User defined P-CHS Cylinders or LBA low word
;       BX:         User defined P-CHS Heads and Sectors or LBA high word
;       DX:         Translate mode or TRANSLATEMODE_AUTO
;       CX:         FLG_DRVPARAMS_USERCHS if user defined CHS in BX:AX
;                   FLG_DRVPARAMS_USERLBA if user defined LBA in BX:AX
;                   Zero if user has not defined capacity
;   Corrupts registers:
;       Nothing
;--------------------------------------------------------------------
GetUserDefinedCapacityToBXAXandFlagsToCXandModeToDXfromROMVARS:
    call    AccessDPT_GetPointerToDRVPARAMStoCSBX

    ; Get settings
    mov     cx, [cs:bx+DRVPARAMS.wFlags]
    mov     dx, cx
    and     cx, BYTE FLG_DRVPARAMS_USERCHS | FLG_DRVPARAMS_USERLBA
    and     dx, BYTE MASK_DRVPARAMS_TRANSLATEMODE
    eSHR_IM dx, TRANSLATEMODE_FIELD_POSITION

    ; Get capacity
    mov     ax, [cs:bx+DRVPARAMS.wCylinders]        ; Or .dwMaximumLBA
    mov     bx, [cs:bx+DRVPARAMS.wHeadsAndSectors]  ; Or .dwMaximumLBA+2
    ret


%ifdef MODULE_EBIOS
;--------------------------------------------------------------------
; StoreLba48AddressingFromCLandTotalSectorCountFromBXDXAX
;   Parameters:
;       BX:DX:AX:   Total Sector Count
;       CL:         FLGL_DPT_LBA48 if LBA48 supported
;       DS:DI:      Ptr to Disk Parameter Table
;   Returns:
;       Nothing
;   Corrupts registers:
;       CL
;--------------------------------------------------------------------
StoreLba48AddressingFromCLandTotalSectorCountFromBXDXAX:
    or      cl, FLGL_DPT_LBA_AND_EBIOS_SUPPORTED
    and     BYTE [di+DPT.bFlagsLow], ~FLGL_DPT_LBA48
    or      [di+DPT.bFlagsLow], cl
    mov     [di+DPT.twLbaSectors], ax
    mov     [di+DPT.twLbaSectors+2], dx
    mov     [di+DPT.twLbaSectors+4], bx
    ret
%endif ; MODULE_EBIOS