/*
* $Id$
*
* Copyright (C) 2003-2015 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.chipset.via;
import org.apache.log4j.Logger;
import org.jnode.driver.bus.pci.PCIDevice;
import org.jnode.driver.bus.pci.PCI_IDs;
/**
* Various fixed for the Via chipset.
*
* @author Ewout Prangsma (epr@users.sourceforge.net)
*/
public class ViaQuirks {
/**
* Lantency fix with the system contains a buggy southbridge.
*
* @param dev
* @param log
*/
public static void applyLatencyFix(PCIDevice dev, Logger log) {
PCIDevice d = dev.getPCIBusAPI().findDevice(PCI_IDs.PCI_VENDOR_ID_VIATEC, 0x686);
if (d != null) {
// For revision 0x40-0x42 we have a buggy southbridge.
final int rev = d.getConfig().getRevision();
if ((rev >= 0x40) && (rev <= 0x42)) {
/*
* Ok we have the problem. Now set the PCI master grant to occur every master
* grant. The apparent bug is that under high PCI load (quite common in Linux of
* course) you can get data loss when the CPU is held off the bus for 3 bus master
* requests This happens to include the IDE controllers....
*
* VIA only apply this fix when an SB Live! is present but under both Linux and
* Windows this isnt enough, and we have seen corruption without SB Live! but with
* things like 3 UDMA IDE controllers. So we ignore that bit of the VIA
* recommendation..
*/
int busarb = dev.readConfigByte(0x76);
/*
* Set bit 4 and bi 5 of byte 76 to 0x01
*/
busarb &= ~(1 << 5);
busarb |= (1 << 4);
dev.writeConfigByte(0x76, busarb);
log.debug("Applying VIA southbridge workaround on device " + dev.getPCIName());
}
}
}
}