Integrate Mempress memory tester (#1253)

generators/chipyard/src/main/scala/config/RocketConfigs.scala

@@ -21,6 +21,16 @@ class TinyRocketConfig extends Config(
   new freechips.rocketchip.subsystem.With1TinyCore ++             // single tiny rocket-core
   new chipyard.config.AbstractConfig)
 
+class MempressRocketConfig extends Config(
+  new mempress.WithMemPress ++                                    // use Mempress (memory traffic generation) accelerator
+  new freechips.rocketchip.subsystem.WithNBanks(8) ++
+  new freechips.rocketchip.subsystem.WithInclusiveCache(nWays=16, capacityKB=2048) ++
+  new chipyard.config.WithExtMemIdBits(7) ++                      // use 7 bits for tl like request id
+  new freechips.rocketchip.subsystem.WithNMemoryChannels(4) ++
+  new chipyard.config.WithSystemBusWidth(128) ++
+  new freechips.rocketchip.subsystem.WithNBigCores(1) ++
+  new chipyard.config.AbstractConfig)
+
 // DOC include start: FFTRocketConfig
 class FFTRocketConfig extends Config(
   new fftgenerator.WithFFTGenerator(numPoints=8, width=16, decPt=8) ++ // add 8-point mmio fft at the default addr (0x2400) with 16bit fixed-point numbers.

generators/chipyard/src/main/scala/config/fragments/PeripheralFragments.scala

@@ -72,3 +72,7 @@ class WithSerialTLBackingMemory extends Config((site, here, up) => {
   )}
 })
 
+class WithExtMemIdBits(n: Int) extends Config((site, here, up) => {
+    case ExtMem => up(ExtMem, site).map(x => x.copy(master = x.master.copy(idBits = n)))
+})
+