Param: Transition to Cycles for relevant parameters

This patch is a first step to using Cycles as a parameter type. The
main affected modules are the CPUs and the Ruby caches. There are
definitely plenty more places that are affected, but this patch serves
as a starting point to making the transition.

An important part of this patch is to actually enable parameters to be
specified as Param.Cycles which involves some changes to params.py.

src/python/m5/params.py

@@ -463,8 +463,6 @@ class CheckedInt(NumericParamValue):
         # most derived types require this, so we just do it here once
         code('%import "stdint.i"')
         code('%import "base/types.hh"')
-        # ignore the case operator for Cycles
-        code('%ignore *::operator uint64_t() const;')
 
     def getValue(self):
         return long(self.value)
@@ -482,13 +480,21 @@ class Int64(CheckedInt):    cxx_type =  'int64_t'; size = 64; unsigned = False
 class UInt64(CheckedInt):   cxx_type = 'uint64_t'; size = 64; unsigned = True
 
 class Counter(CheckedInt):  cxx_type = 'Counter';  size = 64; unsigned = True
-class Cycles(CheckedInt): cxx_type = 'Cycles'; size = 64; unsigned = True
 class Tick(CheckedInt):     cxx_type = 'Tick';     size = 64; unsigned = True
 class TcpPort(CheckedInt):  cxx_type = 'uint16_t'; size = 16; unsigned = True
 class UdpPort(CheckedInt):  cxx_type = 'uint16_t'; size = 16; unsigned = True
 
 class Percent(CheckedInt):  cxx_type = 'int'; min = 0; max = 100
 
+class Cycles(CheckedInt):
+    cxx_type = 'Cycles'
+    size = 64
+    unsigned = True
+
+    def getValue(self):
+        from m5.internal.core import Cycles
+        return Cycles(self.value)
+
 class Float(ParamValue, float):
     cxx_type = 'double'