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asmibus: remove port sharing
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Sebastien Bourdeauducq committed Jun 14, 2013
1 parent 0c52c08 commit ac2cde0e873a8223c5c71f8c284ceb47d9583ffb
Showing with 0 additions and 80 deletions.
  1. +0 −80 migen/bus/asmibus.py
@@ -302,83 +302,3 @@ def do_simulation(self, s):
else:
s.wr(self.hub.call, 0)
self._calling_tag = -1

# Port sharing

class SharedPort:
def __init__(self, base_port):
if not base_port.finalized:
raise FinalizeError
self.finalized = True

nslots = len(base_port.slots)

self.hub = base_port.hub
self.base = base_port.base
# 1 if that slot is assigned to us
self.slots = [Signal() for i in range(nslots)]

# request issuance
self.adr = Signal(self.hub.aw)
self.we = Signal()
self.stb = Signal()
if nslots > 1:
self.tag_issue = Signal(max=nslots)
self.ack = Signal()

# request completion
self.call = Signal()
self.tag_call = Signal(self.hub.tagbits)
self.dat_r = Signal(self.hub.dw)
self.dat_w = Signal(self.hub.dw)
self.dat_wm = Signal(self.hub.dw//8)

def get_call_expression(self, slotn=0):
if not self.finalized:
raise FinalizeError
return self.call \
& (self.tag_call == (self.base + slotn))

class PortSharer(Module):
def __init__(self, base_port, nshares):
self.shared_ports = [SharedPort(base_port) for i in range(nshares)]

###

# request issuance
self.submodules.rr = roundrobin.RoundRobin(nshares, roundrobin.SP_CE)
self.comb += [
self.rr.request.eq(Cat(*[sp.stb for sp in self.shared_ports])),
self.rr.ce.eq(base_port.ack)
]
self.comb += [
base_port.adr.eq(Array(sp.adr for sp in self.shared_ports)[self.rr.grant]),
base_port.we.eq(Array(sp.we for sp in self.shared_ports)[self.rr.grant]),
base_port.stb.eq(Array(sp.stb for sp in self.shared_ports)[self.rr.grant]),
]
if hasattr(base_port, "tag_issue"):
self.comb += [sp.tag_issue.eq(base_port.tag_issue) for sp in self.shared_ports]
self.comb += [sp.ack.eq(base_port.ack & (self.rr.grant == n)) for n, sp in enumerate(self.shared_ports)]

# request completion
self.comb += [sp.call.eq(base_port.call & Array(sp.slots)[base_port.tag_call-base_port.base])
for sp in self.shared_ports]
self.comb += [sp.tag_call.eq(base_port.tag_call) for sp in self.shared_ports]
self.comb += [sp.dat_r.eq(base_port.dat_r) for sp in self.shared_ports]
self.comb += [
base_port.dat_w.eq(optree("|", [sp.dat_w for sp in self.shared_ports])),
base_port.dat_wm.eq(optree("|", [sp.dat_wm for sp in self.shared_ports])),
]

# request ownership tracking
if hasattr(base_port, "tag_issue"):
for sp in self.shared_ports:
self.sync += If(sp.stb & sp.ack, Array(sp.slots)[sp.tag_issue].eq(1))
for n, slot in enumerate(sp.slots):
self.sync += If(base_port.call & (base_port.tag_call == (base_port.base + n)), slot.eq(0))
else:
for sp in self.shared_ports:
self.sync += [
If(sp.stb & sp.ack, sp.slots[0].eq(1)),
If(base_port.call & (base_port.tag_call == base_port.base), sp.slots[0].eq(0))
]

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