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Unroute site routing when removing a cell (#729)
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* Fixes an issue with makeBlackBox trying to remove pins from renamed nets

Signed-off-by: Chris Lavin <[email protected]>

* Adding code to properly unroute site routing of a cell when removed

Signed-off-by: Chris Lavin <[email protected]>

* Tweak description

Signed-off-by: Chris Lavin <[email protected]>

* Add test, more fixes

Signed-off-by: Chris Lavin <[email protected]>

* Fix test failure

Signed-off-by: Chris Lavin <[email protected]>

* Update src/com/xilinx/rapidwright/design/DesignTools.java

Co-authored-by: eddieh-xlnx <[email protected]>
Signed-off-by: Chris Lavin <[email protected]>

* More fixes

Signed-off-by: Chris Lavin <[email protected]>

---------

Signed-off-by: Chris Lavin <[email protected]>
Co-authored-by: eddieh-xlnx <[email protected]>
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@clavin-xlnx @eddieh-xlnx
clavin-xlnx and eddieh-xlnx authored Jul 5, 2023
1 parent 830c4dc commit 188e6c3
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236 changes: 198 additions & 38 deletions src/com/xilinx/rapidwright/design/DesignTools.java
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Original file line number Diff line number Diff line change
Expand Up @@ -1490,6 +1490,168 @@ public static void makeBlackBox(Design d, String hierarchicalCellName) {
}
makeBlackBox(d, inst);
}

/**
* Unroutes the site routing connected to the provided cell's logical pin.
* Preserves other parts of the net if used by other sinks in the site if an
* input. For the unrouting to be successful, this method depends on the site
* routing to be consistent.
*
* @param cell The cell of the pin
* @param logicalPinName The logical pin name source or sink to have routing
* removed.
* @returns A list of site pins (if any) that should also be removed from inter-site routing to complete the unroute.
*/
public static List<SitePinInst> unrouteCellPinSiteRouting(Cell cell, String logicalPinName) {
String physPinName = cell.getPhysicalPinMapping(logicalPinName);
if (physPinName == null) {
physPinName = cell.getDefaultPinMapping(logicalPinName);
}
if (physPinName == null) {
// Assume not routed
return Collections.emptyList();
}
BELPin belPin = cell.getBEL().getPin(physPinName);
SiteInst siteInst = cell.getSiteInst();
Net net = siteInst.getNetFromSiteWire(belPin.getSiteWireName());
if (net == null)
return Collections.emptyList();

List<String> sitePinNames = new ArrayList<>();
List<BELPin> internalTerminals = new ArrayList<>();
List<BELPin> internalSinks = new ArrayList<>();
Set<BELPin> visited = new HashSet<>();
Queue<BELPin> queue = new LinkedList<>();
queue.add(belPin);

while (!queue.isEmpty()) {
BELPin currPin = queue.poll();
visited.add(currPin);
BELPin unrouteSegment = null;
for (BELPin pin : siteInst.getSiteWirePins(currPin.getSiteWireIndex())) {
if (currPin == pin || visited.contains(pin)) {
visited.add(pin);
continue;
}
// Check if it is a site pin, cell pin, sitepip or routethru
switch (pin.getBEL().getBELClass()) {
case PORT: {
// We found a site pin, add it to solution set
sitePinNames.add(pin.getName());
break;
}
case BEL: {
// Check if this is another cell being driven by the net, or a route thru
Cell otherCell = siteInst.getCell(pin.getBEL());
if (otherCell != null) {
if (otherCell.isRoutethru()) {
BELPin otherPin = null;
if (pin.isOutput()) {
assert(otherCell.getPinMappingsP2L().size() == 1);
String otherPinName = otherCell.getPinMappingsP2L().keySet().iterator().next();
otherPin = pin.getBEL().getPin(otherPinName);
} else {
otherPin = LUTTools.getLUTOutputPin(pin.getBEL());
}
if (otherPin != null) {
Net otherNet = siteInst.getNetFromSiteWire(otherPin.getSiteWireName());
if (otherNet != null && net.getName().equals(otherNet.getName())) {
queue.add(otherPin);
// Check if the routethru pin is used by companion LUT
if (otherPin.isInput()) {
String otherBELName = LUTTools.getCompanionLUTName(otherPin.getBEL());
Cell companionCell = siteInst.getCell(otherBELName);
if (companionCell != null
&& companionCell.getLogicalPinMapping(otherPin.getName()) != null) {
// We need to remove the routethru if there are no other sinks
// downstream
if (internalSinks.size() == 0) {
siteInst.removeCell(otherCell.getBEL());
siteInst.unrouteIntraSiteNet(pin, pin);
}
}

}
} else {
// site routing terminates here or is invalid
}
}

} else if (otherCell != cell && otherCell.getLogicalPinMapping(pin.getName()) != null) {
// Don't search farther, we don't need to unroute anything else
if (pin.isInput() && belPin.isInput()) {
internalSinks.add(pin);
} else {
internalTerminals.add(pin);
}

}
}
break;
}
case RBEL: {
// We found a routing BEL, follow its sitepip
SitePIP sitePIP = siteInst.getUsedSitePIP(pin);
if (sitePIP != null) {
BELPin otherPin = pin.isInput() ? sitePIP.getOutputPin() : sitePIP.getInputPin();
Net otherNet = siteInst.getNetFromSiteWire(otherPin.getSiteWireName());
if (otherNet != null && net.getName().equals(otherNet.getName())) {
queue.add(otherPin);
unrouteSegment = otherPin;
} else {
// site routing terminates here or is invalid
}
}
break;
}
}
visited.add(pin);
}
if (unrouteSegment != null && unrouteSegment.isInput() && internalSinks.size() == 0) {
// Unroute this branch of the sitePIP
Net otherNet = siteInst.getNetFromSiteWire(unrouteSegment.getSiteWireName());
siteInst.unrouteIntraSiteNet(unrouteSegment, belPin);
siteInst.routeIntraSiteNet(otherNet, unrouteSegment, unrouteSegment);
}
}

List<SitePinInst> sitePinsToRemove = new ArrayList<>();

// This net is routed internally to the site
for (BELPin internalTerminal : internalTerminals) {
if (internalTerminal.isOutput() && internalSinks.size() > 0) {
continue;
}
if (belPin.isOutput()) {
siteInst.unrouteIntraSiteNet(belPin, internalTerminal);
} else {
siteInst.unrouteIntraSiteNet(internalTerminal, belPin);
}
}
if (internalSinks.size() == 0) {
for (String sitePinName : sitePinNames) {
SitePinInst pin = siteInst.getSitePinInst(sitePinName);
if (pin != null) {
sitePinsToRemove.add(pin);
if (belPin.isInput()) {
siteInst.unrouteIntraSiteNet(pin.getBELPin(), belPin);
} else {
siteInst.unrouteIntraSiteNet(belPin, pin.getBELPin());
}
} else {
// Vivado leaves dual output *MUX partially routed, unroute the site for this MUX pin
// Could also be a cell with no loads
siteInst.unrouteIntraSiteNet(belPin, siteInst.getBELPin(sitePinName, sitePinName));
}
}
if (internalTerminals.size() == 0 && sitePinNames.size() == 0) {
// internal site route with no loads
siteInst.unrouteIntraSiteNet(belPin, belPin);
}
}
return sitePinsToRemove;
}

/**
* Turns the cell named hierarchicalCell into a blackbox and removes any
* associated placement and routing information associated with that instance. In Vivado,
Expand All @@ -1515,6 +1677,8 @@ public static void makeBlackBox(Design d, EDIFHierCellInst hierarchicalCell) {
Set<SiteInst> touched = new HashSet<>();
Map<String,String> boundaryNets = new HashMap<>();

Map<Net, Set<SitePinInst>> pinsToRemove = new HashMap<>();

t.stop().start("Find border nets");
// Find all the nets that connect to the cell (keep them)
for (EDIFPortInst portInst : futureBlackBox.getPortInsts()) {
Expand All @@ -1535,20 +1699,12 @@ public static void makeBlackBox(Design d, EDIFHierCellInst hierarchicalCell) {
for (EDIFHierPortInst sink : sinks) {
Cell c = d.getCell(sink.getFullHierarchicalInstName());
if (c == null || !c.isPlaced()) continue;
SiteInst i = c.getSiteInst();
String logicalPinName = sink.getPortInst().getName();
String sitePinName = c.getCorrespondingSitePinName(logicalPinName);
SitePinInst pin = i.getSitePinInst(sitePinName);
Net staticNet = d.getStaticNet(netType);
Site site = i.getSite();
BELPin snk = c.getBEL().getPin(c.getPhysicalPinMapping(logicalPinName));
if (pin == null && netType == NetType.GND) {
// GND post inside the site, let's unroute the site wires
i.unrouteIntraSiteNet(site.getBELPin("HARD0GND", "0"), snk);
continue;
// Remove all physical nets first
List<SitePinInst> removePins = unrouteCellPinSiteRouting(c, logicalPinName);
for (SitePinInst pin : removePins) {
pinsToRemove.computeIfAbsent(pin.getNet(), $ -> new HashSet<>()).add(pin);
}
removeConnectedRouting(staticNet, Node.getNode(pin.getTile(),pin.getConnectedTileWire()));
i.unrouteIntraSiteNet(site.getBELPin(sitePinName), snk);
}
}
}
Expand All @@ -1557,7 +1713,6 @@ public static void makeBlackBox(Design d, EDIFHierCellInst hierarchicalCell) {

List<EDIFHierCellInst> allLeafs = d.getNetlist().getAllLeafDescendants(hierarchicalCell);

Map<Net, Set<SitePinInst>> pinsToRemove = new HashMap<>();

// Remove all placement and routing information related to the cell to be blackboxed
for (EDIFHierCellInst i : allLeafs) {
Expand All @@ -1571,20 +1726,9 @@ public static void makeBlackBox(Design d, EDIFHierCellInst hierarchicalCell) {

// Remove all physical nets first
for (String logPin : c.getPinMappingsP2L().values()) {
SitePinInst pin = c.getSitePinFromLogicalPin(logPin, null);
if (pin == null) continue;
if (pin.getNet() == null) continue;
Net net = pin.getNet();
pinsToRemove.computeIfAbsent(net, ($) -> new HashSet<>()).add(pin);
if (boundaryNets.containsKey(net.getName())) continue;
if (net.isStaticNet()) continue;
d.removeNet(net);

// Unroute site connections
String physPinName = c.getPhysicalPinMapping(logPin);
if (physPinName != null) {
BELPin belPin = c.getBEL().getPin(physPinName);
si.unrouteIntraSiteNet(belPin, belPin);
List<SitePinInst> removePins = unrouteCellPinSiteRouting(c, logPin);
for (SitePinInst pin : removePins) {
pinsToRemove.computeIfAbsent(pin.getNet(), $ -> new HashSet<>()).add(pin);
}
}
touched.add(c.getSiteInst());
Expand All @@ -1597,51 +1741,67 @@ public static void makeBlackBox(Design d, EDIFHierCellInst hierarchicalCell) {
t.stop().start("cleanup t-prims");

// Clean up any cells from Transformed Prims
String keepPrefix = hierarchicalCell.getFullHierarchicalInstName() + EDIFTools.EDIF_HIER_SEP;
for (SiteInst si : d.getSiteInsts()) {
for (Cell c : si.getCells()) {
if (c.getName().startsWith(hierarchicalCell.getFullHierarchicalInstName() + EDIFTools.EDIF_HIER_SEP)) {
if (c.getName().startsWith(keepPrefix)) {
touched.add(si);
}
}
}

t.stop().start("new net names");

Map<Net, String> netsToUpdate = new HashMap<>();
// Update black box output nets with new net names (those with sinks inside the black box)
Map<Net, String> netsToUpdate = new HashMap<>();
for (Net n : d.getNets()) {
String newName = boundaryNets.get(n.getName());
if (newName != null) {
netsToUpdate.put(n, newName);
}
}

Set<String> updatedNets = new HashSet<>();
// Rename nets if source was removed
Set<String> netsToKeep = new HashSet<>();
for (Entry<Net, String> e : netsToUpdate.entrySet()) {
EDIFHierNet newSource = d.getNetlist().getHierNetFromName(e.getValue());
Net updatedNet = DesignTools.updateNetName(d, e.getKey(), newSource.getNet(), e.getValue());
if (updatedNet != null) {
updatedNets.add(updatedNet.getName());
netsToKeep.add(updatedNet.getName());
}
}

t.stop().start("cleanup siteinsts");

// Keep track of site instances to remove, but keep those supplying static sources
List<SiteInst> siteInstsToRemove = new ArrayList<>();
for (SiteInst siteInst : touched) {
for (SitePinInst pin : siteInst.getSitePinInsts()) {
Net net = pin.getNet();
if (net == null || updatedNets.contains(net.getName()))
continue;
pinsToRemove.computeIfAbsent(net, ($) -> new HashSet<>()).add(pin);
if (siteInst.getCells().size() == 0) {
boolean keepSiteInst = false;
for (SitePinInst pin : siteInst.getSitePinInsts()) {
if (pin.getNet() != null && pin.getNet().isStaticNet() && pin.isOutPin()) {
keepSiteInst = true;
}
}
if (!keepSiteInst) {
siteInstsToRemove.add(siteInst);
}
}
}

batchRemoveSitePins(pinsToRemove, true);

// Clean up SiteInst objects
for (SiteInst siteInst : touched) {
for (SiteInst siteInst : siteInstsToRemove) {
d.removeSiteInst(siteInst);
}

// Remove any stray stubs on any remaining nets
for (Net net : pinsToRemove.keySet()) {
if (net.getFanOut() == 0 && net.hasPIPs()) {
net.unroute();
}
}

t.stop().start("create bbox");

// Make EDIFCell blackbox
Expand Down
15 changes: 14 additions & 1 deletion src/com/xilinx/rapidwright/design/tools/LUTTools.java
View file
Original file line number Diff line number Diff line change
Expand Up @@ -34,6 +34,7 @@
import com.xilinx.rapidwright.design.Design;
import com.xilinx.rapidwright.design.Unisim;
import com.xilinx.rapidwright.device.BEL;
import com.xilinx.rapidwright.device.BELPin;
import com.xilinx.rapidwright.device.Device;
import com.xilinx.rapidwright.edif.EDIFCell;
import com.xilinx.rapidwright.edif.EDIFCellInst;
Expand Down Expand Up @@ -101,7 +102,19 @@ public static String getCompanionLUTName(String lutName) {
}

/**
* Checks if this cell is a LUT (LUT1, LUT2, LUT3,...). A CFGLUT5 will return false.
* Gets the output pin from the BEL of a LUT
*
* @param bel The physical bel site of the LUT
* @return O5 or O6 based on the BEL
*/
public static BELPin getLUTOutputPin(BEL bel) {
return bel.getPin("O" + bel.getName().charAt(1));
}

/**
* Checks if this cell is a LUT (LUT1, LUT2, LUT3,...). A CFGLUT5 will return
* false.
*
* @param c The cell in question
* @return True if this is a LUT[1-6], false otherwise.
*/
Expand Down
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