source: xtideuniversalbios/tags/XTIDE_Universal_BIOS_v1.1.1/Src/Handlers/Int13h/AH0h_HReset.asm

; File name     :   AH0h_HReset.asm
; Project name  :   IDE BIOS
; Created date  :   27.9.2007
; Last update   :   1.7.2010
; Author        :   Tomi Tilli
; Description   :   Int 13h function AH=0h, Disk Controller Reset.

RETRIES_IF_RESET_FAILS      EQU     3
TIMEOUT_BEFORE_RESET_RETRY  EQU     5       ; System timer ticks

; Section containing code
SECTION .text

;--------------------------------------------------------------------
; Int 13h function AH=0h, Disk Controller Reset.
;
; AH0h_HandlerForDiskControllerReset
;   Parameters:
;       AH:     Bios function 0h
;       DL:     Drive number (ignored so all drives are reset)
;               If bit 7 is set all hard disks and floppy disks reset.
;   Parameters loaded by Int13h_Jump:
;       DS:     RAMVARS segment
;   Returns:
;       AH:     Int 13h return status (from drive requested in DL)
;       CF:     0 if succesfull, 1 if error
;       IF:     1
;   Corrupts registers:
;       Flags
;--------------------------------------------------------------------
ALIGN JUMP_ALIGN
AH0h_HandlerForDiskControllerReset:
    push    dx
    push    cx
    push    bx
    push    ax

    eMOVZX  bx, dl                      ; Copy requested drive to BL, zero BH to assume no errors
    call    AH0h_ResetFloppyDrivesWithInt40h
    test    bl, 80h                     ; Reset hard disks too?
    jz      SHORT .Return
    call    AH0h_ResetForeignHardDisks
    call    AH0h_ResetAllOurControllers
ALIGN JUMP_ALIGN
.Return:
    mov     ah, bh                      ; Copy error code to AH
    xor     al, al                      ; Zero AL...
    sub     al, ah                      ; ...and set CF if error
    jmp     Int13h_PopXRegsAndReturn


;--------------------------------------------------------------------
; AH0h_ResetFloppyDrivesWithInt40h
;   Parameters:
;       BL:     Requested drive (DL when entering AH=00h)
;       DL:     Drive number
;   Returns:
;       BH:     Error code from requested drive (if available)
;   Corrupts registers:
;       AX, DL
;--------------------------------------------------------------------   
ALIGN JUMP_ALIGN
AH0h_ResetFloppyDrivesWithInt40h:
    xor     ax, ax                      ; Disk Controller Reset
    and     dl, 7Fh                     ; Clear bit 7
    int     INTV_FLOPPY_FUNC
    jmp     SHORT AH0h_BackupErrorCodeFromTheRequestedDriveToBH


;--------------------------------------------------------------------
; AH0h_ResetForeignHardDisks
;   Parameters:
;       BL:     Requested drive (DL when entering AH=00h)
;       DS:     RAMVARS segment
;   Returns:
;       BH:     Error code from requested drive (if available)
;   Corrupts registers:
;       AX, DL
;--------------------------------------------------------------------   
ALIGN JUMP_ALIGN
AH0h_ResetForeignHardDisks:
    mov     cl, [RAMVARS.bFirstDrv]     ; Load number of first our drive
    and     cx, BYTE 7Fh                ; CX = number of drives to reset
    jz      SHORT .Return
    mov     dl, 80h                     ; Start resetting from drive 80h
ALIGN JUMP_ALIGN
.DriveResetLoop:
    mov     ah, 0Dh                     ; Reset Hard Disk (Alternate reset)
    pushf                               ; Push flags to simulate INT
    cli                                 ; Disable interrupts since INT does that
    call    FAR [RAMVARS.fpOldI13h]
    sti                                 ; Make sure interrupts are enabled again (some BIOSes fails to enable it)
    call    AH0h_BackupErrorCodeFromTheRequestedDriveToBH
    inc     dx                          ; Next drive to reset
    loop    .DriveResetLoop
ALIGN JUMP_ALIGN
.Return:
    ret


;--------------------------------------------------------------------
; AH0h_ResetAllOurControllers
;   Parameters:
;       BL:     Requested drive (DL when entering AH=00h)
;       DS:     RAMVARS segment
;   Returns:
;       BH:     Error code from requested drive (if available)
;   Corrupts registers:
;       AX, CX, DX, DI
;--------------------------------------------------------------------
ALIGN JUMP_ALIGN
AH0h_ResetAllOurControllers:
    push    si
    mov     si, ROMVARS.ideVars0            ; Load offset to first IDEVARS
    call    Initialize_GetIdeControllerCountToCX
ALIGN JUMP_ALIGN
.ResetLoop:
    call    AH0h_ResetIdevarsControllerMasterAndSlaveDrives
    add     si, BYTE IDEVARS_size
    loop    .ResetLoop
.Return:
    pop     si
    ret


;--------------------------------------------------------------------
; AH0h_ResetIdevarsControllerMasterAndSlaveDrives
;   Parameters:
;       BL:     Requested drive (DL when entering AH=00h)
;       CS:SI:  Ptr to IDEVARS
;       DS:     RAMVARS segment
;   Returns:
;       BH:     Error code from requested drive (if available)
;   Corrupts registers:
;       AX, DX, DI
;--------------------------------------------------------------------
ALIGN JUMP_ALIGN
AH0h_ResetIdevarsControllerMasterAndSlaveDrives:
    mov     dx, [cs:si+IDEVARS.wPort]
    call    FindDPT_ForIdeMasterAtPort      ; Find master drive to DL
    jc      SHORT AH0h_ResetMasterAndSlaveDriveWithRetries
    call    FindDPT_ForIdeSlaveAtPort       ; Find slave if master not present
    jc      SHORT AH0h_ResetMasterAndSlaveDriveWithRetries
    ret

;--------------------------------------------------------------------
; AH0h_ResetMasterAndSlaveDriveWithRetries
;   Parameters:
;       BL:     Requested drive (DL when entering AH=00h)
;       DL:     Drive number for master or slave drive
;       DS:     RAMVARS segment
;   Returns:
;       BH:     Error code from requested drive (if available)
;   Corrupts registers:
;       AX, DI
;--------------------------------------------------------------------
ALIGN JUMP_ALIGN
AH0h_ResetMasterAndSlaveDriveWithRetries:
    push    dx
    push    cx
    push    bx
    mov     di, RETRIES_IF_RESET_FAILS
ALIGN JUMP_ALIGN
.RetryLoop:
    call    AHDh_ResetDrive
    jnc     SHORT .Return               ; Jump if successful
    mov     cx, TIMEOUT_BEFORE_RESET_RETRY
    call    SoftDelay_TimerTicks
    dec     di
    jnz     SHORT .RetryLoop
ALIGN JUMP_ALIGN
.Return:
    pop     bx
    pop     cx
    pop     dx
    ; Fall to AH0h_BackupErrorCodeFromTheRequestedDriveToBH

;--------------------------------------------------------------------
; AH0h_BackupErrorCodeFromTheRequestedDriveToBH
;   Parameters:
;       AH:     Error code from the last resetted drive
;       DL:     Drive last resetted
;       BL:     Requested drive (DL when entering AH=00h)
;   Returns:
;       BH:     Backuped error code
;   Corrupts registers:
;       Nothing
;--------------------------------------------------------------------
ALIGN JUMP_ALIGN
AH0h_BackupErrorCodeFromTheRequestedDriveToBH:
    cmp     dl, bl                      ; Requested drive?
    jne     SHORT .Return
    mov     bh, ah
ALIGN JUMP_ALIGN
.Return:
    ret