source: xtideuniversalbios/tags/v2.0.0_beta_3/XTIDE_Universal_BIOS/Src/Handlers/Int13h/AH1Eh_XTCF.asm@ 582

; Project name  :   XTIDE Universal BIOS
; Description   :   Int 13h function AH=1Eh, Lo-tech XT-CF features.

;
; 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

;--------------------------------------------------------------------
; Int 13h function AH=1Eh, Lo-tech XT-CF features.
; This function is supported only by XTIDE Universal BIOS.
;
; AH1Eh_HandlerForXTCFfeatures
;   Parameters:
;       AL, CX: Same as in INTPACK
;       DL:     Translated Drive number
;       DS:DI:  Ptr to DPT (in RAMVARS segment)
;       SS:BP:  Ptr to IDEPACK
;   Parameters on INTPACK:
;       AL:     XT-CF subcommand (see XTCF.inc for more info)
;   Returns with INTPACK:
;       AH:     Int 13h return status
;       CF:     0 if successful, 1 if error
;--------------------------------------------------------------------
AH1Eh_HandlerForXTCFfeatures:
%ifndef USE_186
    call    ProcessXTCFsubcommandFromAL
    jmp     Int13h_ReturnFromHandlerAfterStoringErrorCodeFromAH
%else
    push    Int13h_ReturnFromHandlerAfterStoringErrorCodeFromAH
    ; Fall to ProcessXTCFsubcommandFromAL
%endif


;--------------------------------------------------------------------
; ProcessXTCFsubcommandFromAL
;   Parameters:
;       AL:     XT-CF subcommand (see XTCF.inc for more info)
;       DS:DI:  Ptr to DPT (in RAMVARS segment)
;       SS:BP:  Ptr to IDEPACK
;   Returns:
;       AH:     Int 13h return status
;       CF:     0 if successful, 1 if error
;   Corrupts registers:
;       AL, BX, CX, DX, SI
;--------------------------------------------------------------------
ProcessXTCFsubcommandFromAL:
    ; IS_THIS_DRIVE_XTCF. We check this for all commands.
    call    AccessDPT_IsThisDeviceXTCF
    jne     SHORT XTCFnotFound
    and     ax, BYTE 7Fh                ; Subcommand now in AX (clears AH and CF)
    jz      SHORT .ReturnWithSuccess    ; IS_THIS_DRIVE_XTCF

    ; READ_XTCF_CONTROL_REGISTER_TO_DH
    dec     ax                          ; Subcommand
    jnz     SHORT .SkipReadXtcfControlRegisterToDH
    mov     dx, [di+DPT.wBasePort]
    add     dl, XTCF_CONTROL_REGISTER   ; Will never overflow (keeps CF cleared)
    in      al, dx
    mov     [bp+IDEPACK.intpack+INTPACK.dh], al
.ReturnWithSuccess:
    ret     ; With AH and CF cleared

.SkipReadXtcfControlRegisterToDH:
    ; WRITE_DH_TO_XTCF_CONTROL_REGISTER
    dec     ax                          ; Subcommand
    jnz     SHORT XTCFnotFound          ; Invalid subcommand
    mov     al, [bp+IDEPACK.intpack+INTPACK.dh]
    ; Fall to AH1Eh_ChangeXTCFmodeBasedOnControlRegisterInAL


;--------------------------------------------------------------------
; AH1Eh_ChangeXTCFmodeBasedOnControlRegisterInAL
;   Parameters:
;       AL:     XT-CF Control Register
;       DS:DI:  Ptr to DPT (in RAMVARS segment)
;       SS:BP:  Ptr to IDEPACK
;   Returns:
;       AH:     Int 13h return status
;       CF:     0 if successful, 1 if error
;   Corrupts registers:
;       AL, BX, CX, DX, SI
;--------------------------------------------------------------------
AH1Eh_ChangeXTCFmodeBasedOnControlRegisterInAL:
    ; Output Control Register
    mov     dx, [di+DPT.wBasePort]
    add     dl, XTCF_CONTROL_REGISTER
    out     dx, al

    ; We always need to enable 8-bit mode since 16-bit mode is restored
    ; when controller is reset (AH=00h or 0Dh)
    ePUSH_T bx, AH23h_Enable8bitPioMode

    ; Convert Control Register Contents to device code
    test    al, al
    jz      SHORT .Set8bitPioMode
    cmp     al, XTCF_MEMORY_MAPPED_MODE
    jae     SHORT .SetMemoryMappedMode

; We need to limit block size here. Consider this scenario;
; 1. While in PIO mode or memory mapped mode, the drive is set to do
;    block transfers larger than XTCF_DMA_MODE_MAX_BLOCK_SIZE.
; 2. A call is subsequently made to change device mode to DEVICE_8BIT_XTCF_DMA.
; 3. The call to AH24h_SetBlockSize fails but the change in device mode has been made.

    ; Set DMA Mode
    mov     BYTE [di+DPT_ATA.bDevice], DEVICE_8BIT_XTCF_DMA
    mov     al, [di+DPT_ATA.bBlockSize]
    MIN_U   al, XTCF_DMA_MODE_MAX_BLOCK_SIZE
    jmp     SHORT AH24h_SetBlockSize    ; Returns via AH23h_Enable8bitPioMode

.SetMemoryMappedMode:
    mov     al, DEVICE_8BIT_XTCF_MEMMAP
    SKIP2B  bx

.Set8bitPioMode:
    mov     al, DEVICE_8BIT_XTCF_PIO8
    mov     [di+DPT_ATA.bDevice], al
    ret     ; Via AH23h_Enable8bitPioMode


;--------------------------------------------------------------------
; AH1Eh_DetectXTCFwithBasePortInDX
;   Parameters:
;       DX:     Base I/O port address to check
;   Returns:
;       AH:     RET_HD_SUCCESS if XT-CF is found from port
;               RET_HD_INVALID if XT-CF is not found
;       CF:     Cleared if XT-CF found
;               Set if XT-CF not found
;   Corrupts registers:
;       AL
;--------------------------------------------------------------------
AH1Eh_DetectXTCFwithBasePortInDX:
    push    dx
    add     dl, XTCF_CONTROL_REGISTER_INVERTED_in   ; set DX to XT-CF config register (inverted)
    in      al, dx      ; get value
    mov     ah, al      ; save in ah
    inc     dx          ; set DX to XT-CF config register (non-inverted)
    in      al, dx      ; get value
    not     al          ; invert value
    pop     dx
    sub     ah, al      ; do they match? (clear AH if they do)
    jz      SHORT XTCFfound

XTCFnotFound:
AH1Eh_LoadInvalidCommandToAHandSetCF:
    stc                 ; set carry flag since XT-CF not found
    mov     ah, RET_HD_INVALID
XTCFfound:
    ret                 ; and return