litex/migen/bank/eventmanager.py

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from migen.fhdl.structure import *
from migen.fhdl.module import Module
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from migen.bank.description import *
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from migen.genlib.misc import optree
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class _EventSource(HUID):
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def __init__(self):
HUID.__init__(self)
self.status = Signal() # value in the status register
self.pending = Signal() # value in the pending register + assert irq if unmasked
self.trigger = Signal() # trigger signal interface to the user design
self.clear = Signal() # clearing attempt by W1C to pending register, ignored by some event sources
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# set on a positive trigger pulse
class EventSourcePulse(Module, _EventSource):
def __init__(self):
_EventSource.__init__(self)
self.comb += self.status.eq(0)
self.sync += [
If(self.clear, self.pending.eq(0)),
If(self.trigger, self.pending.eq(1))
]
# set on the falling edge of the trigger, status = trigger
class EventSourceProcess(Module, _EventSource):
def __init__(self):
_EventSource.__init__(self)
self.comb += self.status.eq(self.trigger)
old_trigger = Signal()
self.sync += [
If(self.clear, self.pending.eq(0)),
old_trigger.eq(self.trigger),
If(~self.trigger & old_trigger, self.pending.eq(1))
]
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# all status set by external trigger
class EventSourceLevel(Module, _EventSource):
def __init__(self):
_EventSource.__init__(self)
self.comb += [
self.status.eq(self.trigger),
self.pending.eq(self.trigger)
]
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class EventManager(Module, AutoCSR):
def __init__(self):
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self.irq = Signal()
def do_finalize(self):
sources_u = [v for v in self.__dict__.values() if isinstance(v, _EventSource)]
sources = sorted(sources_u, key=lambda x: x.huid)
n = len(sources)
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self.status = CSR(n)
self.pending = CSR(n)
self.enable = CSRStorage(n)
for i, source in enumerate(sources):
self.comb += [
self.status.w[i].eq(source.status),
If(self.pending.re & self.pending.r[i], source.clear.eq(1)),
self.pending.w[i].eq(source.pending)
]
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irqs = [self.pending.w[i] & self.enable.storage[i] for i in range(n)]
self.comb += self.irq.eq(optree("|", irqs))
def __setattr__(self, name, value):
object.__setattr__(self, name, value)
if isinstance(value, _EventSource):
if self.finalized:
raise FinalizeError
self.submodules += value