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artiq/artiq/gateware/drtio/cdc.py

56 lines
1.7 KiB
Python

from migen import *
from migen.genlib.cdc import PulseSynchronizer
class CrossDomainRequest(Module):
def __init__(self, domain,
req_stb, req_ack, req_data,
srv_stb, srv_ack, srv_data):
dsync = getattr(self.sync, domain)
request = PulseSynchronizer("sys", domain)
reply = PulseSynchronizer(domain, "sys")
self.submodules += request, reply
ongoing = Signal()
self.comb += request.i.eq(~ongoing & req_stb)
self.sync += [
req_ack.eq(reply.o),
If(req_stb, ongoing.eq(1)),
If(req_ack, ongoing.eq(0))
]
if req_data is not None:
req_data_r = Signal.like(req_data)
req_data_r.attr.add("no_retiming")
self.sync += If(req_stb, req_data_r.eq(req_data))
dsync += [
If(request.o, srv_stb.eq(1)),
If(srv_ack, srv_stb.eq(0))
]
if req_data is not None:
dsync += If(request.o, srv_data.eq(req_data_r))
self.comb += reply.i.eq(srv_stb & srv_ack)
class CrossDomainNotification(Module):
def __init__(self, domain, rdomain,
emi_stb, emi_data,
rec_stb, rec_ack, rec_data):
emi_data_r = Signal(len(emi_data))
emi_data_r.attr.add("no_retiming")
dsync = getattr(self.sync, domain)
dsync += If(emi_stb, emi_data_r.eq(emi_data))
ps = PulseSynchronizer(domain, rdomain)
self.submodules += ps
self.comb += ps.i.eq(emi_stb)
rsync = getattr(self.sync, rdomain)
rsync += [
If(rec_ack, rec_stb.eq(0)),
If(ps.o,
rec_data.eq(emi_data_r),
rec_stb.eq(1)
)
]