[ESI] Add signaling standard to channel type

In the past, ESI has only supported valid-ready signaling, so we didn't
need to encode the signaling standard. Since we're about to add FIFO
signaling, we need a way to encode the signaling standard. Create an
enum and add it as a parameter to the channel type, defaulting to
ReadyValid so we don't have to fix a bunch of tests.

include/circt/Dialect/ESI/CMakeLists.txt

@@ -6,6 +6,11 @@ mlir_tablegen(ESIPasses.h.inc -gen-pass-decls)
 add_public_tablegen_target(MLIRESITransformsIncGen)
 add_circt_doc(ESI ESIPasses -gen-pass-doc)
 
+set(LLVM_TARGET_DEFINITIONS ESI.td)
+mlir_tablegen(ESIEnums.h.inc -gen-enum-decls)
+mlir_tablegen(ESIEnums.cpp.inc -gen-enum-defs)
+add_public_tablegen_target(MLIRESIEnumsIncGen)
+
 set(LLVM_TARGET_DEFINITIONS ESIInterfaces.td)
 mlir_tablegen(ESIInterfaces.h.inc -gen-op-interface-decls)
 mlir_tablegen(ESIInterfaces.cpp.inc -gen-op-interface-defs)

include/circt/Dialect/ESI/ESIDialect.h

@@ -57,4 +57,7 @@ Operation *buildESIWrapper(OpBuilder &b, Operation *mod,
 
 #include "circt/Dialect/ESI/ESIDialect.h.inc"
 
+// Pull in all enum type definitions and utility function declarations.
+#include "circt/Dialect/ESI/ESIEnums.h.inc"
+
 #endif

include/circt/Dialect/ESI/ESIPorts.td

@@ -14,8 +14,20 @@
 //
 //===----------------------------------------------------------------------===//
 
+include "mlir/IR/AttrTypeBase.td"
+include "mlir/IR/EnumAttr.td"
+
+
 class ESI_Port<string name> : TypeDef<ESI_Dialect, name> {}
 
+def ChannelSignalingValidReady : I32EnumAttrCase<"ValidReady", 0>;
+def ChannelSignaling : I32EnumAttr<
+    "ChannelSignaling",
+    "ESI channel wire signaling standard",
+    [ChannelSignalingValidReady]>{
+  let cppNamespace = "::circt::esi";
+}
+
 def ChannelType : ESI_Port<"Channel"> {
   let summary = "An ESI-compatible channel port";
   let description = [{
@@ -33,9 +45,20 @@ def ChannelType : ESI_Port<"Channel"> {
   }];
 
   let mnemonic = "channel";
-  let parameters = (ins "Type":$inner);
+  let parameters = (ins
+      "Type":$inner,
+      DefaultValuedParameter<
+        "::circt::esi::ChannelSignaling",
+        "::circt::esi::ChannelSignaling::ValidReady">:$signaling);
 
-  let assemblyFormat = "`<` $inner `>`";
+  let assemblyFormat = "`<` $inner (`,` $signaling^)? `>`";
+ 
+  let builders = [
+    TypeBuilder<(ins "Type":$type), [{
+        return Base::get(type.getContext(), type,
+                         ::circt::esi::ChannelSignaling::ValidReady);
+      }]>,
+  ];
 }
 
 //=========

lib/Dialect/ESI/CMakeLists.txt

@@ -61,6 +61,7 @@ add_circt_dialect_library(CIRCTESI
 
   DEPENDS
   MLIRESITransformsIncGen
+  MLIRESIEnumsIncGen
   ${ESI_Deps}
 
   LINK_COMPONENTS

lib/Dialect/ESI/ESIDialect.cpp

@@ -330,4 +330,7 @@ circt::esi::buildESIWrapper(OpBuilder &b, Operation *pearl,
   return shell;
 }
 
+// Provide implementations for the enums we use.
+#include "circt/Dialect/ESI/ESIEnums.cpp.inc"
+
 #include "circt/Dialect/ESI/ESIDialect.cpp.inc"

test/Dialect/ESI/connectivity.mlir

@@ -6,7 +6,7 @@ hw.module @Sender() -> (x: !esi.channel<i1>) {
   %ch, %rcvrRdy = esi.wrap.vr %0, %0 : i1
   hw.output %ch : !esi.channel<i1>
 }
-hw.module @Reciever(%a: !esi.channel<i1>) {
+hw.module @Reciever(%a: !esi.channel<i1, ValidReady>) {
   %rdy = arith.constant 1 : i1
   // Recieve bits.
   %data, %valid = esi.unwrap.vr %a, %rdy : i1