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rtio: support single-master CRI arbiter

This commit is contained in:
Sebastien Bourdeauducq 2016-12-01 16:30:11 +08:00
parent a318243083
commit 6c97a97d8c
1 changed files with 24 additions and 21 deletions
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45
artiq/gateware/rtio/cri.py
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@ -160,30 +160,33 @@ class CRIArbiter(Module):
# # # # # #
selected = Signal(max=len(masters)) if len(masters) == 1:
self.comb += masters[0].connect(slave)
else:
selected = Signal(max=len(masters))
# mux master->slave signals # mux master->slave signals
for name, size, direction in layout: for name, size, direction in layout:
if direction == DIR_M_TO_S: if direction == DIR_M_TO_S:
choices = Array(getattr(m, name) for m in masters) choices = Array(getattr(m, name) for m in masters)
self.comb += getattr(slave, name).eq(choices[selected]) self.comb += getattr(slave, name).eq(choices[selected])
# connect slave->master signals # connect slave->master signals
for name, size, direction in layout: for name, size, direction in layout:
if direction == DIR_S_TO_M: if direction == DIR_S_TO_M:
source = getattr(slave, name) source = getattr(slave, name)
for i, m in enumerate(masters): for i, m in enumerate(masters):
dest = getattr(m, name) dest = getattr(m, name)
if name == "arb_gnt": if name == "arb_gnt":
self.comb += dest.eq(source & (selected == i)) self.comb += dest.eq(source & (selected == i))
else: else:
self.comb += dest.eq(source) self.comb += dest.eq(source)
# select master # select master
self.sync += \ self.sync += \
If(~slave.arb_req, If(~slave.arb_req,
[If(m.arb_req, selected.eq(i)) for i, m in enumerate(masters)] [If(m.arb_req, selected.eq(i)) for i, m in enumerate(masters)]
) )
class CRIInterconnectShared(Module): class CRIInterconnectShared(Module):