firesim: Add a config with no mem port

[davidbiancolin]

Related PRs / Issues:

Type of change:

• Bug fix
• New feature
• Other enhancement

Impact:

• RTL change
• Software change (RISC-V software)
• Build system change
• Other

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[michael-etzkorn]

Not sure if the ordering comes into play since I haven't looked at WithFireSimConfigTweaks but I think some users would like a RocketNoMemPortConfig with no FireSim so this could be two separate configs.

Something like:

 class NoMemPortRocketConfig extends Config(
  new freechips.rocketchip.subsystem.WithNoMemPort ++
  new testchipip.WithBackingScratchpad ++
  new chipyard.RocketConfig)

class FireSimNoMemPortConfig extends Config(
  new WithDefaultFireSimBridges ++
  new WithFireSimConfigTweaks ++
  new chipyard.NoMemPortRocketConfig)

[davidbiancolin]

@michael-etzkorn That would be great. If you wanted to PR that I'd highly appreciate it as i'm quite short on time atm.

[michael-etzkorn]

@michael-etzkorn That would be great. If you wanted to PR that I'd highly appreciate it as i'm quite short on time atm.

Probably best to merge this now and I'll make a note to make a PR to break it up. That PR will probably happen whenever I circle back to my chipyard-related project and am bumping chipyard versions.