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multiplexer: cleanup/pep8

This commit is contained in:
Florent Kermarrec 2016-05-02 15:57:39 +02:00
parent 3177f7964f
commit d3ff63b978
1 changed files with 53 additions and 18 deletions
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71
litedram/core/multiplexer.py
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@ -16,9 +16,11 @@ class _CommandChooser(Module):
self.want_reads = Signal()
self.want_writes = Signal()
self.want_cmds = Signal()
a = len(requests[0].a)
ba = len(requests[0].ba)
# cas/ras/we are 0 when valid is inactive
self.cmd = cmd = stream.Endpoint(cmd_request_rw_layout(len(requests[0].a),
len(requests[0].ba)))
self.cmd = cmd = stream.Endpoint(cmd_request_rw_layout(a, ba))
# # #
@ -47,7 +49,10 @@ class _CommandChooser(Module):
for name in ["cas", "ras", "we"]:
# we should only assert those signals when valid is 1
choices = Array(getattr(req, name) for req in requests)
self.comb += If(cmd.valid, getattr(cmd, name).eq(choices[arbiter.grant]))
self.comb += \
If(cmd.valid,
getattr(cmd, name).eq(choices[arbiter.grant])
)
for i, request in enumerate(requests):
self.comb += \
@ -70,6 +75,7 @@ class _Steerer(Module):
return 0
else:
return cmd.valid & getattr(cmd, attr)
for phase, sel in zip(dfi.phases, self.sel):
self.comb += [
phase.cke.eq(1),
@ -84,14 +90,26 @@ class _Steerer(Module):
phase.bank.eq(Array(cmd.ba for cmd in commands)[sel]),
phase.cas_n.eq(~Array(cmd.cas for cmd in commands)[sel]),
phase.ras_n.eq(~Array(cmd.ras for cmd in commands)[sel]),
phase.we_n.eq(~Array(cmd.we for cmd in commands)[sel]),
phase.rddata_en.eq(Array(valid_and(cmd, "is_read") for cmd in commands)[sel]),
phase.wrdata_en.eq(Array(valid_and(cmd, "is_write") for cmd in commands)[sel])
phase.we_n.eq(~Array(cmd.we for cmd in commands)[sel])
]
rddata_ens = Array(valid_and(cmd, "is_read") for cmd in commands)
wrdata_ens = Array(valid_and(cmd, "is_write") for cmd in commands)
self.sync += [
phase.rddata_en.eq(rddata_ens[sel]),
phase.wrdata_en.eq(wrdata_ens[sel])
]
class Multiplexer(Module, AutoCSR):
def __init__(self, phy_settings, geom_settings, timing_settings, controller_settings, bank_machines, refresher, dfi, lasmic,
def __init__(self,
phy_settings,
geom_settings,
timing_settings,
controller_settings,
bank_machines,
refresher,
dfi,
lasmic,
with_bandwidth=False):
assert(phy_settings.nphases == len(dfi.phases))
self.phy_settings = phy_settings
@ -107,8 +125,10 @@ class Multiplexer(Module, AutoCSR):
]
# Command steering
nop = Record(cmd_request_layout(geom_settings.addressbits, geom_settings.bankbits))
commands = [nop, choose_cmd.cmd, choose_req.cmd, refresher.cmd] # nop must be 1st
nop = Record(cmd_request_layout(geom_settings.addressbits,
geom_settings.bankbits))
# nop must be 1st
commands = [nop, choose_cmd.cmd, choose_req.cmd, refresher.cmd]
(STEER_NOP, STEER_CMD, STEER_REQ, STEER_REFRESH) = range(4)
steerer = _Steerer(commands, dfi)
self.submodules += steerer
@ -116,9 +136,11 @@ class Multiplexer(Module, AutoCSR):
# Read/write turnaround
read_available = Signal()
write_available = Signal()
reads = [req.valid & req.is_read for req in requests]
writes = [req.valid & req.is_write for req in requests]
self.comb += [
read_available.eq(reduce(or_, [req.valid & req.is_read for req in requests])),
write_available.eq(reduce(or_, [req.valid & req.is_write for req in requests]))
read_available.eq(reduce(or_, reads)),
write_available.eq(reduce(or_, writes))
]
def anti_starvation(timeout):
@ -136,13 +158,15 @@ class Multiplexer(Module, AutoCSR):
else:
self.comb += max_time.eq(0)
return en, max_time
read_time_en, max_read_time = anti_starvation(controller_settings.read_time)
write_time_en, max_write_time = anti_starvation(controller_settings.write_time)
# Refresh
self.comb += [bm.refresh_req.eq(refresher.req) for bm in bank_machines]
go_to_refresh = Signal()
self.comb += go_to_refresh.eq(reduce(and_, [bm.refresh_gnt for bm in bank_machines]))
bm_refresh_gnts = [bm.refresh_gnt for bm in bank_machines]
self.comb += go_to_refresh.eq(reduce(and_, bm_refresh_gnts))
# Datapath
all_rddata = [p.rddata for p in dfi.phases]
@ -183,9 +207,13 @@ class Multiplexer(Module, AutoCSR):
steerer_sel(steerer, phy_settings, "read"),
If(write_available,
# TODO: switch only after several cycles of ~read_available?
If(~read_available | max_read_time, NextState("RTW"))
If(~read_available | max_read_time,
NextState("RTW")
)
),
If(go_to_refresh, NextState("REFRESH"))
If(go_to_refresh,
NextState("REFRESH")
)
)
fsm.act("WRITE",
write_time_en.eq(1),
@ -194,16 +222,23 @@ class Multiplexer(Module, AutoCSR):
choose_req.cmd.ready.eq(1),
steerer_sel(steerer, phy_settings, "write"),
If(read_available,
If(~write_available | max_write_time, NextState("WTR"))
If(~write_available | max_write_time,
NextState("WTR")
)
),
If(go_to_refresh, NextState("REFRESH"))
If(go_to_refresh,
NextState("REFRESH")
)
)
fsm.act("REFRESH",
steerer.sel[0].eq(STEER_REFRESH),
refresher.ack.eq(1),
If(~refresher.req, NextState("READ"))
If(~refresher.req,
NextState("READ")
)
fsm.delayed_enter("RTW", "WRITE", phy_settings.read_latency-1) # FIXME: reduce this, actual limit is around (cl+1)/nphases
)
# TODO: reduce this, actual limit is around (cl+1)/nphases
fsm.delayed_enter("RTW", "WRITE", phy_settings.read_latency-1)
fsm.delayed_enter("WTR", "READ", timing_settings.tWTR-1)
if controller_settings.with_bandwidth: