/*
* $Id$
*
* Copyright (C) 2003-2014 JNode.org
*
* This library is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published
* by the Free Software Foundation; either version 2.1 of the License, or
* (at your option) any later version.
*
* This library 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 Lesser General Public
* License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this library; If not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
package org.jnode.driver.net._3c90x;
import org.jnode.net.SocketBuffer;
import org.jnode.net.ethernet.EthernetConstants;
import org.jnode.system.resource.MemoryResource;
import org.jnode.system.resource.ResourceManager;
import org.vmmagic.unboxed.Address;
/**
* @author epr
*/
public class _3c90xTxBuffer implements _3c90xConstants {
private static final int DPD_SIZE = 16;
private static final int FRAME_SIZE = EthernetConstants.ETH_FRAME_LEN;
/**
* The actual data
*/
private final byte[] data;
/**
* MemoryResource mapper around data
*/
private final MemoryResource mem;
/**
* Offset within mem of first DPD
*/
private final int firstDPDOffset;
/**
* Offset within mem of first ethernet frame
*/
private final int firstFrameOffset;
/**
* 32-bit address first DPD
*/
private final Address firstDPDAddress;
/**
* 32-bit address of first ethernet frame
*/
private final Address firstFrameAddress;
/**
* Create a new instance
*
* @param rm
*/
public _3c90xTxBuffer(ResourceManager rm) {
// Create a large enough buffer
final int size = (DPD_SIZE + FRAME_SIZE) + 16 /* alignment */;
this.data = new byte[size];
this.mem = rm.asMemoryResource(data);
final Address memAddr = mem.getAddress();
int addr = memAddr.toInt();
int offset = 0;
// Align on 16-byte boundary
while ((addr & 15) != 0) {
addr++;
offset++;
}
this.firstDPDOffset = offset;
this.firstDPDAddress = memAddr.add(firstDPDOffset);
this.firstFrameOffset = firstDPDOffset + DPD_SIZE;
this.firstFrameAddress = memAddr.add(firstFrameOffset);
}
/**
* Initialize this ring to its default (empty) state
*/
public void initialize(SocketBuffer src) throws IllegalArgumentException {
// Setup the DPD
final int dpdOffset = firstDPDOffset;
// Copy the data from the buffer
final int len = src.getSize();
if (len > FRAME_SIZE) {
throw new IllegalArgumentException("Length must be <= ETH_FRAME_LEN");
}
src.get(data, firstFrameOffset, 0, len);
// Set next DPD ptr
mem.setInt(dpdOffset + 0, 0);
// Set frame start header
mem.setInt(dpdOffset + 4, 0x8000); // txIndicate
// Set fragment address
mem.setInt(dpdOffset + 8, firstFrameAddress.toInt());
// Set fragment size
mem.setInt(dpdOffset + 12, len | (1 << 31));
}
/**
* Gets the address of the first DPD in this buffer.
*/
public Address getFirstDPDAddress() {
return firstDPDAddress;
}
}