csr.reg: simplify field reset values.

amaranth_soc/csr/reg.py

@@ -114,6 +114,8 @@ class FieldMap:
         The amount of bits required to store the field map.
     shape : :class:`StructLayout`
         Shape of the field map.
+    reset : dict
+        The reset value associated with the field map.
     """
     def __init__(self, fields):
         offset = 0
@@ -145,29 +147,11 @@ def size(self):
 
     @property
     def shape(self):
-        return data.StructLayout({
-            name: field.shape for name, field in self
-        })
+        return data.StructLayout({name: field.shape for name, field in self})
 
     @property
     def reset(self):
-        """Get the reset value associated with the field map.
-
-        Returns
-        -------
-        A nested dict of a :class:`str` as keys to an :class:`int` or integral Enum, depending on
-        the reset value of each :class:`GenericField`.
-        """
-        reset = dict()
-        for key, field in self:
-            if isinstance(field, GenericField):
-                reset[key] = field.reset
-            elif isinstance(field, FieldMap):
-                for sub_name, sub_field in field.all_fields():
-                    reset[key] = field.reset
-            else:
-                assert False # :nocov:
-        return reset
+        return {key: field.reset for key, field in self}
 
     def __getitem__(self, key):
         """Retrieve a field from the field map.
@@ -261,6 +245,10 @@ def __init__(self, field, length):
     def shape(self):
         return data.ArrayLayout(self._field.shape, self._length)
 
+    @property
+    def reset(self):
+        return [self._field.reset for key in range(self._length)]
+
     def __getitem__(self, key):
         """Retrieve a field from the field array.
 

tests/test_csr_reg.py

@@ -141,7 +141,7 @@ def test_simple(self):
 
         self.assertEqual(field_array.size, 16)
         self.assertEqual(field_array.shape, data.ArrayLayout(unsigned(2), 8))
-        self.assertEqual(field_array.reset, dict(enumerate(3 for _ in range(8))))
+        self.assertEqual(field_array.reset, [3 for _ in range(8)])
         for i in range(8):
             self.assertEqual(field_array[i], csr.field.R(unsigned(2), reset=3))
 
@@ -152,8 +152,7 @@ def test_dim_2(self):
         self.assertEqual(field_array.size, 16)
         self.assertEqual(field_array.shape,
                          data.ArrayLayout(data.ArrayLayout(unsigned(1), length=4), length=4))
-        self.assertEqual(field_array.reset,
-                         dict(enumerate(dict(enumerate(1 for _ in range(4))) for _ in range(4))))
+        self.assertEqual(field_array.reset, [[1 for _ in range(4)] for _ in range(4)])
         for i in range(4):
             self.assertEqual(field_array[i],
                              csr.FieldArray(csr.field.R(1, reset=1), length=4))
@@ -172,8 +171,7 @@ def test_nested(self):
                              "b": data.ArrayLayout(unsigned(1), length=4),
                          }), length=4))
         self.assertEqual(field_array.reset,
-                         dict(enumerate({"a": 0xa, "b": dict(enumerate(0 for _ in range(4)))}
-                                        for _ in range(4))))
+                         [{"a": 0xa, "b":[0,0,0,0]} for _ in range(4)])
         for i in range(4):
             self.assertEqual(field_array[i], csr.FieldMap({
                 "a": csr.field.R(unsigned(4), reset=0xa),