; Project name : XTIDE Universal BIOS ; Description : IDE Read/Write functions for transferring ; block using DMA. ; These functions should only be called from IdeTransfer.asm. ; ; 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 ;-------------------------------------------------------------------- ; IdeDmaBlock_WriteToXTCF ; Parameters: ; CX: Block size in 512 byte sectors ; DX: XTCF Base Port Address ; ES:SI: Physical address to buffer to receive data ; Returns: ; Nothing ; Corrupts registers: ; AX, BX, CX, DX ;-------------------------------------------------------------------- ALIGN JUMP_ALIGN IdeDmaBlock_WriteToXTCF: xchg si, di mov bl, CHANNEL_3 | READ | AUTOINIT_DISABLE | ADDRESS_INCREMENT | DEMAND_MODE call TransferBlockToOrFromXTCF xchg di, si ret ;-------------------------------------------------------------------- ; IdeDmaBlock_ReadFromXTCF ; Parameters: ; CX: Block size in 512 byte sectors ; DX: XTCF Base Port Address ; ES:DI: Physical address to buffer to receive data ; Returns: ; Nothing ; Corrupts registers: ; AX, BX, CX, DX ;-------------------------------------------------------------------- ALIGN JUMP_ALIGN IdeDmaBlock_ReadFromXTCF: mov bl, CHANNEL_3 | WRITE | AUTOINIT_DISABLE | ADDRESS_INCREMENT | DEMAND_MODE ; Fall to TransferBlockToOrFromXTCF ;-------------------------------------------------------------------- ; TransferBlockToOrFromXTCF ; Parameters: ; BL: Mode byte for DMA Mode Register ; CX: Block size in 512 byte sectors ; DX: XTCF Base Port Address ; ES:DI: Physical address to buffer to receive data ; Returns: ; Nothing ; Corrupts registers: ; AX, BX, CX, DX ;-------------------------------------------------------------------- TransferBlockToOrFromXTCF: ; 8-bit DMA transfers must be done within 64k physical page. ; XT-CF support maximum of 64 sector (32768 bytes) blocks in DMA mode ; so we never need to separate transfer to more than 2 separate DMA operations. ; Load XT-CF Control Register port to DX add dl, XTCF_CONTROL_REGISTER ; Calculate bytes for first page mov ax, di neg ax ; AX = Max BYTEs for first page %ifdef USE_186 shl cx, 9 ; CX = Block size in BYTEs %else xchg cl, ch shl cx, 1 %endif cmp cx, ax jbe SHORT .TransferLastDmaPageWithSizeInCX ; Push size for second DMA page xchg cx, ax ; CX = BYTEs for first page sub ax, cx ; AX = BYTEs for second page push ax ; Transfer first DMA page call StartDMAtransferForXTCFwithDmaModeInBL pop cx ; Pop size for second DMA page .TransferLastDmaPageWithSizeInCX: ; Fall to StartDMAtransferForXTCFwithDmaModeInBL ;-------------------------------------------------------------------- ; StartDMAtransferForXTCFwithDmaModeInBL ; Parameters: ; BL: Byte for DMA Mode Register ; CX: Number of BYTEs to transfer (1...32768 since max block size is limited to 64) ; DX: XTCF Control Register ; Returns: ; Nothing ; Corrupts registers: ; AX ;-------------------------------------------------------------------- ALIGN JUMP_ALIGN StartDMAtransferForXTCFwithDmaModeInBL: ; Program 8-bit DMA Controller ; Disable Interrupts and DMA Channel 3 during DMA setup mov al, SET_CH3_MASK_BIT cli ; Disable interrupts out MASK_REGISTER_DMA8_out, al ; Disable DMA Channel 3 ; Set DMA Mode (read or write using channel 3) mov al, bl out MODE_REGISTER_DMA8_out, al ; Set address to DMA controller out CLEAR_FLIPFLOP_DMA8_out, al ; Reset flip-flop to low byte mov ax, es out PAGE_DMA8_CH_3, al mov ax, di out BASE_AND_CURRENT_ADDRESS_REGISTER_DMA8_CH3_out, al ; Low byte mov al, ah out BASE_AND_CURRENT_ADDRESS_REGISTER_DMA8_CH3_out, al ; High byte ; Set number of bytes to transfer (DMA controller must be programmed number of bytes - 1) mov ax, cx dec ax ; DMA controller is programmed for one byte less out BASE_AND_CURRENT_COUNT_REGISTER_DMA8_CH3_out, al ; Low byte mov al, ah out BASE_AND_CURRENT_COUNT_REGISTER_DMA8_CH3_out, al ; High byte ; Enable DMA Channel 3 mov al, CLEAR_CH3_MASK_BIT out MASK_REGISTER_DMA8_out, al ; Enable DMA Channel 3 sti ; Enable interrupts %if 0 ; Slow DMA code ; XT-CF transfers 16 bytes at a time. We need to manually ; start transfer for every block. ALIGN JUMP_ALIGN .TransferNextBlock: mov al, RAISE_DRQ_AND_CLEAR_XTCF_XFER_COUNTER cli ; We want no ISR to read DMA Status Register before we do out dx, al ; Transfer up to 16 bytes to/from XT-CF card ; * Here XT-CF sets CPU to wait states during transfer * in al, STATUS_REGISTER_DMA8_in sti test al, FLG_CH3_HAS_REACHED_TERMINAL_COUNT jz SHORT .TransferNextBlock ; All bytes transferred? %endif ; Slow DMA code %if 1 ; Fast DMA code push cx add cx, BYTE 15 ; Include any partial DMA block (since we had to divide transfer to 64k physical pages) eSHR_IM cx, 4 ; Drive Block size to 16 Byte DMA Block Size .JustOneMoreDmaBlock: mov al, RAISE_DRQ_AND_CLEAR_XTCF_XFER_COUNTER ALIGN JUMP_ALIGN .TransferNextDmaBlock: out dx, al ; Transfer 16 bytes to/from XT-CF card loop .TransferNextDmaBlock inc cx ; set up CX, in case we need to do an extra iteration in al, STATUS_REGISTER_DMA8_in test al, FLG_CH3_HAS_REACHED_TERMINAL_COUNT jz SHORT .JustOneMoreDmaBlock ; it wasn't set so get more bytes pop cx %endif ; Fast DMA code ; Restore XT-CF to normal operation mov al, XTCF_DMA_MODE out dx, al ; Increment physical address in ES:DI mov ax, es add di, cx adc al, ah mov es, ax ret