119 lines
3.4 KiB
Python
119 lines
3.4 KiB
Python
from migen.fhdl.structure import *
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def regprefix(prefix, registers):
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for register in registers:
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register.name = prefix + register.name
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return registers
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class RegisterRaw:
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def __init__(self, name, size=1):
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self.name = name
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self.size = size
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self.re = Signal()
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self.r = Signal(self.size)
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self.w = Signal(self.size)
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(READ_ONLY, WRITE_ONLY, READ_WRITE) = range(3)
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class Field:
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def __init__(self, name, size=1, access_bus=READ_WRITE, access_dev=READ_ONLY, reset=0, atomic_write=False):
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self.name = name
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self.size = size
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self.access_bus = access_bus
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self.access_dev = access_dev
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self.storage = Signal(self.size, reset=reset)
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self.atomic_write = atomic_write
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if self.access_bus == READ_ONLY and self.access_dev == WRITE_ONLY:
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self.w = Signal(self.size)
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else:
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if self.access_dev == READ_ONLY or self.access_dev == READ_WRITE:
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self.r = Signal(self.size)
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if self.access_dev == WRITE_ONLY or self.access_dev == READ_WRITE:
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self.w = Signal(self.size)
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self.we = Signal()
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class RegisterFields:
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def __init__(self, name, fields):
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self.name = name
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self.fields = fields
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class RegisterField(RegisterFields):
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def __init__(self, name, size=1, access_bus=READ_WRITE, access_dev=READ_ONLY, reset=0, atomic_write=False):
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self.field = Field(name, size, access_bus, access_dev, reset, atomic_write)
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super().__init__(name, [self.field])
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(ALIAS_NON_ATOMIC, ALIAS_ATOMIC_HOLD, ALIAS_ATOMIC_COMMIT) = range(3)
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class FieldAlias:
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def __init__(self, mode, f, start, end, commit_list):
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self.mode = mode
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self.size = end - start
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self.access_bus = f.access_bus
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self.access_dev = f.access_dev
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if mode == ALIAS_ATOMIC_HOLD:
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self.storage = Signal(end-start, name="atomic_hold")
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self.commit_to = f.storage[start:end]
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else:
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self.storage = f.storage[start:end]
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if mode == ALIAS_ATOMIC_COMMIT:
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self.commit_list = commit_list
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else:
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self.commit_list = []
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# device access is through the original field
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def expand_description(description, busword):
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d = []
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for reg in description:
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if isinstance(reg, RegisterRaw):
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if reg.size > busword:
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raise ValueError("Raw register larger than a bus word")
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d.append(reg)
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elif isinstance(reg, RegisterFields):
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f = []
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offset = 0
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totalsize = 0
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for field in reg.fields:
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offset += field.size
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totalsize += field.size
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if offset > busword:
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# add padding
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padding = busword - (totalsize % busword)
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if padding != busword:
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totalsize += padding
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offset += padding
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top = field.size
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commit_list = []
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while offset > busword:
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if field.atomic_write:
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if offset - busword > busword:
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mode = ALIAS_ATOMIC_HOLD
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else:
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# last iteration
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mode = ALIAS_ATOMIC_COMMIT
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else:
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mode = ALIAS_NON_ATOMIC
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slice1 = busword - offset + top
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slice2 = min(offset - busword, busword)
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if slice1:
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alias = FieldAlias(mode, field, top - slice1, top, commit_list)
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f.append(alias)
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if mode == ALIAS_ATOMIC_HOLD:
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commit_list.append(alias)
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top -= slice1
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d.append(RegisterFields(reg.name, f))
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alias = FieldAlias(mode, field, top - slice2, top, commit_list)
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f = [alias]
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if mode == ALIAS_ATOMIC_HOLD:
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commit_list.append(alias)
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top -= slice2
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offset -= busword
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else:
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f.append(field)
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if f:
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d.append(RegisterFields(reg.name, f))
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else:
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raise TypeError
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return d
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