source: xtideuniversalbios/trunk/XTIDE_Universal_BIOS/Src/Initialization/DetectDrives.asm@ 479

; Project name  :   XTIDE Universal BIOS
; Description   :   Functions for detecting drive for the BIOS.

;
; XTIDE Universal BIOS and Associated Tools 
; Copyright (C) 2009-2010 by Tomi Tilli, 2011-2012 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

;--------------------------------------------------------------------
; Detects all IDE hard disks to be controlled by this BIOS.
;
; DetectDrives_FromAllIDEControllers
;   Parameters:
;       DS:     RAMVARS segment
;       ES:     BDA segment (zero)
;   Returns:
;       Nothing
;   Corrupts registers:
;       All (not segments)
;--------------------------------------------------------------------
DetectDrives_FromAllIDEControllers:
    call    RamVars_GetIdeControllerCountToCX
    mov     bp, ROMVARS.ideVars0            ; CS:BP now points to first IDEVARS

.DriveDetectLoop:                           ; Loop through IDEVARS
    push    cx

    mov     cx, g_szDetectMaster
    mov     bh, MASK_DRVNHEAD_SET                               ; Select Master drive
    call    StartDetectionWithDriveSelectByteInBHandStringInCX  ; Detect and create DPT + BOOTNFO

    mov     cx, g_szDetectSlave
    mov     bh, MASK_DRVNHEAD_SET | FLG_DRVNHEAD_DRV
    call    StartDetectionWithDriveSelectByteInBHandStringInCX

    pop     cx

    add     bp, BYTE IDEVARS_size           ; Point to next IDEVARS

%ifdef MODULE_SERIAL
    jcxz    .AddHardDisks                   ; Set to zero on .ideVarsSerialAuto iteration (if any)
%endif
    loop    .DriveDetectLoop

%ifdef MODULE_SERIAL
;----------------------------------------------------------------------
;
; if serial drive detected, do not scan (avoids duplicate drives and isn't needed - we already have a connection)
;
    call    FindDPT_ToDSDIforSerialDevice
    jnc     .AddHardDisks

    mov     bp, ROMVARS.ideVarsSerialAuto   ; Point to our special IDEVARS structure, just for serial scans

    mov     al,[cs:ROMVARS.wFlags]          ; Configurator set to always scan?
    or      al,[es:BDA.bKBFlgs1]            ; Or, did the user hold down the ALT key?
    and     al,8                            ; 8 = alt key depressed, same as FLG_ROMVARS_SERIAL_ALWAYSDETECT
    jnz     .DriveDetectLoop
%endif

.AddHardDisks:
;----------------------------------------------------------------------
;
; Add in hard disks to BDA, finalize our Count and First variables
;
; Note that we perform the add to bHDCount and store bFirstDrv even if the count is zero.
; This is done because we use the value of .bFirstDrv to know how many drives were in the system
; at the time of boot, and to return that number on int13h/8h calls.  Because the count is zero,
; FindDPT_ForDriveNumber will not find any drives that are ours.
;
    mov     cx, [RAMVARS.wDrvCntAndFlopCnt]     ; Our count of hard disks

    mov     al, [es:BDA.bHDCount]
    add     cl, al                      ; Add our drives to the system count
    mov     [es:BDA.bHDCount], cl
    or      al, 80h                     ; Or in hard disk flag
    mov     [RAMVARS.bFirstDrv], al     ; Store first drive number

.AddFloppies:
%ifdef MODULE_SERIAL_FLOPPY
;----------------------------------------------------------------------
;
; Add in any emulated serial floppy drives, finalize our packed Count and First variables
;
    dec     ch
    mov     al, ch
    js      .NoFloppies                     ; if no drives are present, we store 0ffh

    call    FloppyDrive_GetCountFromBIOS_or_BDA

    push    ax

    add     al, ch                          ; Add our drives to existing drive count
    cmp     al, 3                           ; For BDA, max out at 4 drives (ours is zero based)
    jb      .MaxBDAFloppiesExceeded
    mov     al, 3
.MaxBDAFloppiesExceeded:
    eROR_IM al, 2                           ; move to bits 6-7
    inc     ax                              ; low order bit, indicating floppy drive exists

    mov     ah, [es:BDA.wEquipment]         ; Load Equipment WORD low byte
    and     ah, 03eh                        ; Mask off drive number and drives present bit
    or      al, ah                          ; Or in new values
    mov     [es:BDA.wEquipment], al         ; and store

    mov     al, 1eh                         ; BDA pointer to Floppy DPT
    mov     si, AH8h_FloppyDPT
    call    Interrupts_InstallHandlerToVectorInALFromCSSI

    pop     ax

    shr     ch, 1                           ; number of drives, 1 or 2 only, to CF flag (clear=1, set=2)
    rcl     al, 1                           ; starting drive number in upper 7 bits, number of drives in low bit
.NoFloppies:
    mov     [RAMVARS.xlateVars+XLATEVARS.bFlopCntAndFirst], al
%endif

    ret

%ifndef CHECK_FOR_UNUSED_ENTRYPOINTS
    %if FLG_ROMVARS_SERIAL_SCANDETECT != 8
        %error "DetectDrives is currently coded to assume that FLG_ROMVARS_SERIAL_SCANDETECT is the same bit as the ALT key code in the BDA.  Changes in the code will be needed if these values are no longer the same."
    %endif
%endif


;--------------------------------------------------------------------
; StartDetectionWithDriveSelectByteInBHandStringInCX
;   Parameters:
;       BH:     Drive Select byte for Drive and Head Register
;       CX:     Offset to "Master" or "Slave" string
;       CS:BP:  Ptr to IDEVARS for the drive
;       DS:     RAMVARS segment
;       ES:     Zero (BDA segment)
;   Returns:
;       None
;   Corrupts registers:
;       AX, BL, CX, DX, SI, DI
;--------------------------------------------------------------------
StartDetectionWithDriveSelectByteInBHandStringInCX:
    ; Autodetect port for XT-CF
%ifdef MODULE_8BIT_IDE
    call    DetectDrives_DoesIdevarsInCSBPbelongToXTCF
    jne     SHORT .SkipXTCFportDetection

    ; XT-CF do not support slave drives so skip detection
    test    bh, FLG_DRVNHEAD_DRV
    jnz     SHORT NoSlaveDriveAvailable

    ; XT-CF do not support slave drives so we can safely update port
    ; for next drive (another XT-CF card on same system)
.DetectNextPort:
    call    BootVars_GetNextXTCFportToDetectToDX
    cmp     dx, XTCF_BASE_PORT_4
    ja      SHORT .SkipXTCFportDetection        ; XT-CF not found from any port

    call    AH1Eh_DetectXTCFwithBasePortInDX
    jc      SHORT .DetectNextPort               ; XT-CF not found from this port

    ; We now have autodetected port in DX
    push    dx
    xchg    ax, dx                              ; Port to print in AX
    call    DetectPrint_StartDetectWithAutodetectedBasePortInAXandIdeVarsInCSBP
    jmp     SHORT .DriveDetectionStringPrintedOnScreen

    ; Print detect string for devices that do not support autodetection     
.SkipXTCFportDetection:
    push    dx
%endif ; MODULE_8BIT_IDE

    call    DetectPrint_StartDetectWithMasterOrSlaveStringInCXandIdeVarsInCSBP
.DriveDetectionStringPrintedOnScreen:
%ifdef MODULE_HOTKEYS
    call    HotkeyBar_UpdateDuringDriveDetection
%endif
%ifdef MODULE_8BIT_IDE
    pop     dx
%endif
    ; Fall to .ReadAtaInfoFromHardDisk


;--------------------------------------------------------------------
; .ReadAtaInfoFromHardDisk
;   Parameters:
;       BH:     Drive Select byte for Drive and Head Register
;       DX:     Autodetected port (for devices that support autodetection)
;       CS:BP:  Ptr to IDEVARS for the drive
;       DS:     RAMVARS segment
;       ES:     Zero (BDA segment)
;   Returns:
;       CF:     Cleared if ATA-information read successfully
;               Set if any error
;   Corrupts registers:
;       AX, BL, CX, DX, SI, DI
;--------------------------------------------------------------------
.ReadAtaInfoFromHardDisk:
    mov     si, BOOTVARS.rgbAtaInfo     ; ES:SI now points to ATA info location
    push    es
    push    si
    push    dx
    push    bx
    call    Device_IdentifyToBufferInESSIwithDriveSelectByteInBH
    pop     bx
    pop     dx
    pop     si
    pop     es
    jnc     SHORT CreateBiosTablesForHardDisk
    ; Fall to .ReadAtapiInfoFromDrive

.ReadAtapiInfoFromDrive:                ; Not yet implemented
    ;call   ReadAtapiInfoFromDrive      ; Assume CD-ROM
    ;jnc    SHORT _CreateBiosTablesForCDROM

    ;jmp    short DetectDrives_DriveNotFound
;;; fall-through instead of previous jmp instruction
;--------------------------------------------------------------------
; DetectDrives_DriveNotFound
;   Parameters:
;       Nothing
;   Returns:
;       CF:     Set (from BootMenuPrint_NullTerminatedStringFromCSSIandSetCF)
;   Corrupts registers:
;       AX, SI
;--------------------------------------------------------------------
DetectDrives_DriveNotFound:
    mov     si, g_szNotFound
    jmp     DetectPrint_NullTerminatedStringFromCSSIandSetCF


;--------------------------------------------------------------------
; CreateBiosTablesForHardDisk
;   Parameters:
;       BH:     Drive Select byte for Drive and Head Register
;       DX:     Autodetected port (for devices that support autodetection)
;       CS:BP:  Ptr to IDEVARS for the drive
;       ES:SI   Ptr to ATA information for the drive
;       DS:     RAMVARS segment
;       ES:     BDA segment
;   Returns:
;       Nothing
;   Corrupts registers:
;       AX, BX, CX, DX, SI, DI
;--------------------------------------------------------------------
CreateBiosTablesForHardDisk:
    push    bx
    call    AtaID_VerifyFromESSI
    pop     bx
    jc      SHORT DetectDrives_DriveNotFound
    call    CreateDPT_FromAtaInformation
    jc      SHORT DetectDrives_DriveNotFound
    call    DriveDetectInfo_CreateForHardDisk
    jmp     SHORT DetectPrint_DriveNameFromDrvDetectInfoInESBX


%ifdef MODULE_8BIT_IDE
;--------------------------------------------------------------------
; DetectDrives_DoesIdevarsInCSBPbelongToXTCF
;   Parameters:
;       CS:BP:  Ptr to IDEVARS for the drive
;   Returns:
;       ZF:     Set if IDEVARS belongs to XT-CF device
;               Cleared if some other device
;   Corrupts registers:
;       AL
;--------------------------------------------------------------------
DetectDrives_DoesIdevarsInCSBPbelongToXTCF:
    mov     al, [cs:bp+IDEVARS.bDevice]
    cmp     al, DEVICE_8BIT_XTCF_PIO8
    je      SHORT .DeviceIsXTCF
    cmp     al, DEVICE_8BIT_XTCF_DMA
    je      SHORT .DeviceIsXTCF
    cmp     al, DEVICE_8BIT_XTCF_MEMMAP
.DeviceIsXTCF:
NoSlaveDriveAvailable:
    ret
%endif ; MODULE_8BIT_IDE