dma.c

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/*-
 * Copyright (c) 2002-2018 The UbixOS Project.
 * All rights reserved.
 *
 * This was developed by Christopher W. Olsen for the UbixOS Project.
 *
 * Redistribution and use in source and binary forms, with or without modification, are permitted
 * provided that the following conditions are met:
 *
 * 1) Redistributions of source code must retain the above copyright notice, this list of
 *    conditions, the following disclaimer and the list of authors.
 * 2) Redistributions in binary form must reproduce the above copyright notice, this list of
 *    conditions, the following disclaimer and the list of authors in the documentation and/or
 *    other materials provided with the distribution.
 * 3) Neither the name of the UbixOS Project nor the names of its contributors may be used to
 *    endorse or promote products derived from this software without specific prior written
 *    permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
 * OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
 
#include <sys/dma.h>
#include <sys/io.h>
 
#define lowByte(x)  (x & 0x00FF)
#define highByte(x) ((x & 0xFF00) >> 8)
 
static uInt8 maskReg[8] = { 0x0A, 0x0A, 0x0A, 0x0A, 0xD4, 0xD4, 0xD4, 0xD4 };
static uInt8 clearReg[8] = { 0x0C, 0x0C, 0x0C, 0x0C, 0xD8, 0xD8, 0xD8, 0xD8 };
static uInt8 modeReg[8] = { 0x0B, 0x0B, 0x0B, 0x0B, 0xD6, 0xD6, 0xD6, 0xD6 };
static uInt8 addrPort[8] = { 0x00, 0x02, 0x04, 0x06, 0xC0, 0xC4, 0xC8, 0xCC };
static uInt8 pagePort[8] = { 0x87, 0x83, 0x81, 0x82, 0x8F, 0x8B, 0x89, 0x8A };
static uInt8 countPort[8] = { 0x01, 0x03, 0x05, 0x07, 0xC2, 0xC6, 0xCA, 0xCE };
 
void dmaXfer(uint8_t channel, uint32_t address, uInt length, uint8_t read) {
  unsigned char page = 0, mode = 0;
  unsigned int offset = 0;
  if (read) {
    mode = 0x48 + channel;
  }
  else {
    mode = 0x44 + channel;
  }
  page = address >> 16;
  offset = address & 0xFFFF;
  length--;
  _dmaXfer(channel, page, offset, length, mode);
}
 
void _dmaXfer(uInt8 dmaChannel, uInt8 page, uInt offset, uInt length, uInt8 mode) {
  //asm("cli");
  outportByte(maskReg[dmaChannel], 0x04 | dmaChannel);
  outportByte(clearReg[dmaChannel], 0x00);
  outportByte(modeReg[dmaChannel], mode);
  outportByte(addrPort[dmaChannel], lowByte(offset));
  outportByte(addrPort[dmaChannel], highByte(offset));
  outportByte(pagePort[dmaChannel], page);
  outportByte(countPort[dmaChannel], lowByte(length));
  outportByte(countPort[dmaChannel], highByte(length));
  outportByte(maskReg[dmaChannel], dmaChannel);
  //asm("sti");
}