57 lines
1.5 KiB
Python
57 lines
1.5 KiB
Python
from migen.fhdl import structure as f
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from migen.corelogic import roundrobin, multimux
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from .simple import Simple, GetSigName
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from functools import partial
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_desc = [
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(True, "adr", 32),
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(True, "dat", 32),
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(False, "dat", 32),
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(True, "sel", 4),
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(True, "cyc", 1),
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(True, "stb", 1),
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(False, "ack", 1),
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(True, "we", 1),
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(True, "cti", 3),
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(True, "bte", 2),
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(False, "err", 1)
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]
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class Master(Simple):
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def __init__(self, name=""):
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Simple.__init__(self, _desc, False, name)
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class Slave(Simple):
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def __init__(self, name=""):
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Simple.__init__(self, _desc, True, name)
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class Arbiter:
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def __init__(self, masters, target):
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self.masters = masters
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self.target = target
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self.rr = roundrobin.Inst(len(self.masters))
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def GetFragment(self):
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comb = []
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# mux master->slave signals
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m2s_names = [GetSigName(x, False) for x in _desc if x[0]]
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m2s_masters = [[getattr(m, name) for name in m2s_names] for m in self.masters]
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m2s_target = [getattr(self.target, name) for name in m2s_names]
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comb += multimux.MultiMux(self.rr.grant, m2s_masters, m2s_target)
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# connect slave->master signals
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s2m_names = [GetSigName(x, False) for x in _desc if not x[0]]
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for name in s2m_names:
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source = getattr(self.target, name)
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for m in self.masters:
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dest = getattr(m, name)
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comb.append(f.Assign(dest, source))
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# connect bus requests to round-robin selector
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reqs = [m.cyc_o for m in self.masters]
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comb.append(f.Assign(self.rr.request, f.Cat(*reqs)))
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return f.Fragment(comb) + self.rr.GetFragment()
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