source: xtideuniversalbios/trunk/XTIDE_Universal_BIOS_Configurator_v2/Src/FlashSST.asm@ 621

; Project name  :   XTIDE Universal BIOS Configurator v2
; Description   :   Functions for flashing SST flash devices.

;
; XTIDE Universal BIOS and Associated Tools
; Copyright (C) 2009-2010 by Tomi Tilli, 2011-2021 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

;--------------------------------------------------------------------
; FlashSst_WithFlashvarsInDSSI
;   Parameters:
;       DS:BX:  Ptr to FLASHVARS
;   Returns:
;       Updated FLASHVARS in DS:BX
;   Corrupts registers:
;       AX, DX, DI
;--------------------------------------------------------------------
ALIGN JUMP_ALIGN
FlashSst_WithFlashvarsInDSBX:
    push    ds
    push    es
    push    bx
    push    cx
    push    si
    push    bp
    mov     bp, bx                  ; Flashvars now in SS:BP (Assumes SS=DS)

    mov     BYTE [bp+FLASHVARS.flashResult], FLASH_RESULT.DeviceNotDetected
    call    DetectSstDevice
    jc      SHORT .ExitOnError

    call    CalibrateSstTimeout

    mov     BYTE [bp+FLASHVARS.flashResult], FLASH_RESULT.PollingTimeoutError
    mov     cx, [bp+FLASHVARS.wPagesToFlash]
    mov     dx, [bp+FLASHVARS.wEepromPageSize]
    les     di, [bp+FLASHVARS.fpNextSourcePage]
    lds     si, [bp+FLASHVARS.fpNextDestinationPage]
%ifdef CLD_NEEDED
    cld
%endif

ALIGN JUMP_ALIGN
.NextPage:
    ; See if this page needs updating.
    push    si
    push    di
    push    cx
    mov     cx, dx
    repe cmpsb
    pop     cx
    pop     di
    pop     si
    jne     SHORT .FlashThisPage
    add     si, dx
    add     di, dx
    jmp     SHORT .ContinueLoop

.FlashThisPage:
    call    EraseSstPage
    jc      SHORT .ExitOnError
    call    WriteSstPage
    jc      SHORT .ExitOnError
.ContinueLoop:
    loop    .NextPage

    ; The write process has already confirmed the results one byte at a time.
    ; Here we do an additional verify check just in case there was some
    ; kind of oddity with pages / addresses.
    mov     BYTE [bp+FLASHVARS.flashResult], FLASH_RESULT.DataVerifyError
%ifndef USE_186
    mov     ax, [bp+FLASHVARS.wPagesToFlash]
    mov     cl, SST_PAGE_SIZE_SHIFT - 1     ; -1 because we compare WORDs (verifying 64 KB won't work otherwise)
    shl     ax, cl
    xchg    cx, ax
%else
    mov     cx, [bp+FLASHVARS.wPagesToFlash]
    shl     cx, SST_PAGE_SIZE_SHIFT - 1
%endif
    lds     si, [bp+FLASHVARS.fpNextSourcePage]
    les     di, [bp+FLASHVARS.fpNextDestinationPage]
    repe cmpsw
    jne     SHORT .ExitOnError

%ifndef CHECK_FOR_UNUSED_ENTRYPOINTS
%if FLASH_RESULT.success = 0    ; Just in case this should ever change
    mov     [bp+FLASHVARS.flashResult], cl
%else
    mov     BYTE [bp+FLASHVARS.flashResult], FLASH_RESULT.success
%endif
%endif
ALIGN JUMP_ALIGN
.ExitOnError:
    pop     bp
    pop     si
    pop     cx
    pop     bx
    pop     es
    pop     ds
    ret

;--------------------------------------------------------------------
; DetectSstDevice
;   Parameters:
;       SS:BP:  Ptr to FLASHVARS
;   Returns:
;       CF: Clear if supported SST device found
;           Set if supported SST device not found
;   Corrupts registers:
;       AX, BX, SI, DS
;--------------------------------------------------------------------
ALIGN JUMP_ALIGN
DetectSstDevice:
    lds     si, [bp+FLASHVARS.fpNextDestinationPage]
    mov     bx, 5555h

    cli
    mov     BYTE [bx], 0AAh         ; Enter software ID sequence.
    shr     bx, 1                   ; BX=2AAAh, CF=1
    mov     BYTE [bx], 55h
    eRCL_IM bx, 1                   ; BX=5555h
    mov     BYTE [bx], 90h
    mov     al, [si]                ; Extra reads to be sure device
    mov     al, [si]                ; has time to respond.
    mov     al, [si]
    mov     ah, [si]                ; Vendor ID in AH.
    mov     al, [si+1]              ; Device ID in AL.
    mov     BYTE [bx], 0F0h         ; Exit software ID.
    sti

    cmp     ax, 0BFB4h
    jb      SHORT .NotValidDevice
    cmp     ax, 0BFB7h+1
    cmc
.NotValidDevice:
    ret

;--------------------------------------------------------------------
; CalibrateSstTimeout
;   Parameters:
;       SS:BP:  Ptr to FLASHVARS
;   Returns:
;       FLASHVARS.wTimeoutCounter
;   Corrupts registers:
;       AX, BX, CX, SI, DI, DS, ES
;--------------------------------------------------------------------
ALIGN JUMP_ALIGN
CalibrateSstTimeout:
    LOAD_BDA_SEGMENT_TO es, cx, !
    mov     ds, [bp+FLASHVARS.fpNextDestinationPage+2]
    mov     bx, BDA.dwTimerTicks
    mov     si, cx
    mov     di, cx
    mov     al, [di]
    inc     ax                      ; Forces poll to fail

    mov     ah, [es:bx]             ; Read low byte only
    inc     ah
.WaitForFirstIncrement:
    cmp     ah, [es:bx]
    jne     SHORT .WaitForFirstIncrement

    inc     ah

.WaitForSecondIncrement:
    inc     ch                      ; CX now 0x0100
.PollLoop:                          ; Identical to poll loop used
    cmp     [di], al                ; during programming
    loopne  .PollLoop               ; Will never be equal in this case
    inc     si                      ; Number of poll loops completed
    jz      SHORT .CountOverflow
    cmp     ah, [es:bx]
    jne     SHORT .WaitForSecondIncrement
    SKIP1B  al
.CountOverflow:
    ; Clamp on overflow, although it should not be possible on
    ; real hardware. In principle SI could overflow on a very
    ; fast CPU. However the SST device is on a slow bus. Even
    ; running at the min read cycle time of fastest version of
    ; the device, SI can not overflow.
    dec     si

    ; SI ~= number of polling loops in 215us.
    mov     [bp+FLASHVARS.wTimeoutCounter], si
    ret

;--------------------------------------------------------------------
; EraseSstPage
;   Parameters:
;       DS:SI:  Destination ptr
;   Returns:
;       CF:     Set on error.
;   Corrupts registers:
;       AX, BX
;--------------------------------------------------------------------
ALIGN JUMP_ALIGN
EraseSstPage:
    push    cx

    mov     bx, 5555h
    mov     ax, 2AAAh

    ; Sector erase sequence.
    mov     [bx], al                ; [5555h] <- AAh
    xchg    bx, ax
    mov     [bx], al                ; [2AAAh] <- 55h
    xchg    bx, ax
    mov     BYTE [bx], 80h          ; [5555h] <- 80h
    mov     [bx], al                ; [5555h] <- AAh
    xchg    bx, ax
    mov     [bx], al                ; [2AAAh] <- 55h
    mov     BYTE [si], 30h

    or      bl, al                  ; BL = 0FFh
    mov     ax, 1163                ; 1163 x ~215us = 250ms = 10x datasheet max
.TimeoutOuterLoop:
    mov     cx, [bp+FLASHVARS.wTimeoutCounter]
.TimeoutInnerLoop:
    cmp     [si], bl                ; Will return 0FFh when erase complete
    loopne  .TimeoutInnerLoop
    je      SHORT .Return
    dec     ax
    jnz     SHORT .TimeoutOuterLoop
    ; Timed out (CF=1)
.Return:
    pop     cx
    ret

;--------------------------------------------------------------------
; WriteSstPage
;   Parameters:
;       DX:     EEPROM page size
;       DS:SI:  Destination ptr
;       ES:DI:  Source ptr
;   Returns:
;       SI, DI: Each advanced forward 1 page.
;       CF:     Set on error.
;   Corrupts registers:
;       AL, BX
;--------------------------------------------------------------------
ALIGN JUMP_ALIGN
WriteSstPage:
    push    cx
    push    dx

    mov     bx, [bp+FLASHVARS.wTimeoutCounter]
    xchg    si, di
    cli

.NextByte:
    es lodsb                        ; Read byte from ES:SI
    mov     BYTE [5555h], 0AAh      ; Byte program sequence.
    mov     BYTE [2AAAh], 55h
    mov     BYTE [5555h], 0A0h
    mov     [di], al                ; Write byte to DS:DI

    mov     cx, bx
.WaitLoop:
    cmp     [di], al                ; Device won't return actual data until write complete.
    loopne  .WaitLoop               ; Timeout ~215us, or ~10x 20us max program time from datasheet.
    jne     SHORT .WriteTimeout

    inc     di
    dec     dx
    jnz     SHORT .NextByte
    SKIP1B  al
.WriteTimeout:
    stc
    sti
    xchg    si, di
    pop     dx
    pop     cx
    ret