get route fail net in rapidwright

[coherent17]

Hi Rapidwright experts, I have a quick question about the net not being fully routed(ROUTE_STATUS != ROUTED) in Vivado, how can I access these nets in rapidwright?

Some of them are partial routed due to site pin conflict!

Any suggestions and recommendations are appreciated!

Thanks

[clavin-xlnx]

Hi Rapidwright experts, I have a quick question about the net not being fully routed(ROUTE_STATUS != ROUTED) in Vivado, how can I access these nets in rapidwright?

Some of them are partial routed due to site pin conflict!

In RapidWright, accessing partially routed nets is not as direct. A isRouted field in the SitePinInst class is populated lazily by DesignTools.updatePinIsRouted(Design). Then, you can iterate through all the nets in the design, excluding those that have no PIPs and check for pins that are not routed:

Design design = Design.readCheckpoint("your.dcp");
DesignTools.updatePinsIsRouted(design);
for (Net n : design.getNets()) {
    if (n.hasPIPs()) {
        for (SitePinInst p : n.getPins()) {
            if (!p.isRouted()) {
                System.out.println("Pin " + p + " on partially routed Net " + n + " is not routed.");
            }
        }                
    }
}

[coherent17]

Hi Rapidwright experts, I have a quick question about the net not being fully routed(ROUTE_STATUS != ROUTED) in Vivado, how can I access these nets in rapidwright?
Some of them are partial routed due to site pin conflict!

In RapidWright, accessing partially routed nets is not as direct. A isRouted field in the SitePinInst class is populated lazily by DesignTools.updatePinIsRouted(Design). Then, you can iterate through all the nets in the design, excluding those that have no PIPs and check for pins that are not routed:

Design design = Design.readCheckpoint("your.dcp");
DesignTools.updatePinsIsRouted(design);
for (Net n : design.getNets()) {
    if (n.hasPIPs()) {
        for (SitePinInst p : n.getPins()) {
            if (!p.isRouted()) {
                System.out.println("Pin " + p + " on partially routed Net " + n + " is not routed.");
            }
        }                
    }
}

Hi Chris,
Thanks for the advice, but the code snippet above isn't working—I still can't access the unrouted/partially routed net!

If a net is only partially routed due to a site pin conflict, does that mean another net has already been routed through that site pin, preventing the current net from using it? And is this site pin still marked as unrouted in that case?

Thanks

[clavin-xlnx]

Interesting, would you be willing to share the design in question? Or, a design the replicates the issue you are seeing? We don't explicitly identify conflicts, but perhaps the code could be improved to handle these cases.

[coherent17]

Interesting, would you be willing to share the design in question? Or, a design the replicates the issue you are seeing? We don't explicitly identify conflicts, but perhaps the code could be improved to handle these cases.

Hi Chris,

Sorry, I'm not allowed to do that! Hopefully I can come up some WA and send a PR to help in the future, thanks again!

[eddieh-xlnx]

Can you elaborate on:

I still can't access the unrouted/partially routed net!

please? If you do Design.getNet("<net name>"), does the net come up? If it does, does it have all the SitePinInst objects you expect associated with it?

Note that Design.readCheckpoint() may not cause all SitePinInst objects to be created, and so there may not be anything to update. You may want to try add the following lines to perform a more complete analysis:

Design design = Design.readCheckpoint("your.dcp");
DesignTools.makePhysNetNamesConsistent(design);
DesignTools.createMissingSitePinInsts(design);

Also, what version of Vivado are you using?

[coherent17]

Hi Eddieh,

I'm using Vivado 2024.1!
But currently I lost the route fail design due to some reason. I'll try your suggestions when I meet route fail design and get back to you here soon!

Thanks for your help!

[coherent17]

Can you elaborate on:

I still can't access the unrouted/partially routed net!

please? If you do Design.getNet("<net name>"), does the net come up? If it does, does it have all the SitePinInst objects you expect associated with it?

Note that Design.readCheckpoint() may not cause all SitePinInst objects to be created, and so there may not be anything to update. You may want to try add the following lines to perform a more complete analysis:

Design design = Design.readCheckpoint("your.dcp");
DesignTools.makePhysNetNamesConsistent(design);
DesignTools.createMissingSitePinInsts(design);

Also, what version of Vivado are you using?

Hi Eddieh Chris,

Sorry for the delay response, I got the route fail design now, after quick test, the root cause is just as Eddieh mentioned above:

DesignTools.makePhysNetNamesConsistent(design);
DesignTools.createMissingSitePinInsts(design);

I also tried

DesignTools.toCSV(filename, design);

I can see the route fail name inside the output csv files!

Can you share why the above 2 lines should be added in the code snippet?
Is it to optimize for performance issue to default not setup so much detail about the design?

Thanks again!

Coherent

[clavin-xlnx]

Can you share why the above 2 lines should be added in the code snippet? Is it to optimize for performance issue to default not setup so much detail about the design?

Physical nets have a single name that is usually named after the driver pin. Many logical nets can map to the same (parent) physical net. Sometimes, one of the logical net alias names gets used as a physical net name and this can cause some confusion. To eliminate this issue, we run DesignTools.makePhysNetNamesConsistent() so that all physical net names follow the convention of being named after their parent net name (driver pin).

As Eddie mentioned above, the reason for DesignTools.createMissingSitePinInsts() is to ensure that SitePinInst objects are created for all connections. This is not guaranteed by simply loading a DCP. Thus, we need to have these present in order to know if they are routed or not.

[coherent17]

Can you share why the above 2 lines should be added in the code snippet? Is it to optimize for performance issue to default not setup so much detail about the design?

Physical nets have a single name that is usually named after the driver pin. Many logical nets can map to the same (parent) physical net. Sometimes, one of the logical net alias names gets used as a physical net name and this can cause some confusion. To eliminate this issue, we run DesignTools.makePhysNetNamesConsistent() so that all physical net names follow the convention of being named after their parent net name (driver pin).

As Eddie mentioned above, the reason for DesignTools.createMissingSitePinInsts() is to ensure that SitePinInst objects are created for all connections. This is not guaranteed by simply loading a DCP. Thus, we need to have these present in order to know if they are routed or not.

Hi Chris,

Thanks for your detail explanation!