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bank/eventmanager: refactor, rename EventSourceLevel -> EventSourcePr…
…ocess, add fully externally controlled event source
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Sebastien Bourdeauducq committed May 8, 2013
1 parent 7a74dae commit b9b6df6f291f8d1377f5175adc050a900bf9404e
Showing with 42 additions and 34 deletions.
  1. +42 −34 migen/bank/eventmanager.py
@@ -6,14 +6,41 @@
class _EventSource(HUID):
def __init__(self):
HUID.__init__(self)
self.trigger = Signal()
self.pending = Signal()
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

class EventSourcePulse(_EventSource):
pass
# 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))
]

class EventSourceLevel(_EventSource):
pass
# 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)
]

class EventManager(Module, AutoCSR):
def __init__(self):
@@ -27,38 +54,19 @@ def do_finalize(self):
self.pending = CSR(n)
self.enable = CSRStorage(n)

# status
for i, source in enumerate(sources):
if isinstance(source, EventSourcePulse):
self.comb += self.status.w[i].eq(0)
elif isinstance(source, EventSourceLevel):
self.comb += self.status.w[i].eq(source.trigger)
else:
raise TypeError

# pending
for i, source in enumerate(sources):
# W1C
self.sync += If(self.pending.re & self.pending.r[i], source.pending.eq(0))
if isinstance(source, EventSourcePulse):
# set on a positive trigger pulse
self.sync += If(source.trigger, source.pending.eq(1))
elif isinstance(source, EventSourceLevel):
# set on the falling edge of the trigger
old_trigger = Signal()
self.sync += [
old_trigger.eq(source.trigger),
If(~source.trigger & old_trigger, source.pending.eq(1))
]
else:
raise TypeError
self.comb += self.pending.w[i].eq(source.pending)
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)
]

# IRQ
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):
if isinstance(value, _EventSource) and self.finalized:
raise FinalizeError
object.__setattr__(self, name, value)
if isinstance(value, _EventSource):
if self.finalized:
raise FinalizeError
self.submodules += value

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