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ltssm: Add Recovery.Active/Configuration states.

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This commit is contained in:
Florent Kermarrec 2022-04-26 15:40:29 +02:00
parent 464efdaf7c
commit e92a6efa19
2 changed files with 59 additions and 5 deletions
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2
usb3_pipe/core.py
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@ -61,7 +61,7 @@ class USB3PIPE(Module):
# LTSSM ------------------------------------------------------------------------------------
ltssm = LTSSM(serdes=serdes, lfps_unit=lfps, ts_unit=ts, sys_clk_freq=sys_clk_freq)
self.submodules.ltssm = ltssm
self.comb += self.ready.eq(ltssm.polling.idle)
self.comb += self.ready.eq(ltssm.polling.idle | ltssm.polling.recovery)
# Scrambling -------------------------------------------------------------------------------
scrambler = Scrambler()

62
usb3_pipe/ltssm.py
View File

@ -174,6 +174,7 @@ class PollingFSM(Module):
""" Polling Finite State Machine (section 7.5.4)"""
def __init__(self, serdes, lfps_unit, ts_unit, sys_clk_freq, with_timers=True):
self.idle = Signal()
self.recovery = Signal()
self.rx_ready = Signal()
self.tx_ready = Signal()
self.exit_to_compliance = Signal()
@ -193,6 +194,10 @@ class PollingFSM(Module):
_12_ms_timer = WaitTimer(int(12e-3*sys_clk_freq))
self.submodules += _12_ms_timer
# 6ms Timer -------------------------------------------------------------------------------
_6_ms_timer = WaitTimer(int(6e-3*sys_clk_freq))
self.submodules += _6_ms_timer
# FSM --------------------------------------------------------------------------------------
self.submodules.fsm = fsm = FSM(reset_state="Polling.Entry")
@ -251,13 +256,13 @@ class PollingFSM(Module):
),
# Go to Configuration if at least 8 consecutive TS1 or TS1_INV seen (8 ensured by ts_unit)
If(ts_unit.rx_ts1,
NextValue(serdes.rx_polarity, 0),
If(~self.recovery, NextValue(serdes.rx_polarity, 0)),
_12_ms_timer.wait.eq(0),
NextValue(rx_ts2_seen, 0),
NextState("Polling.Configuration")
),
If(ts_unit.rx_ts1_inv,
NextValue(serdes.rx_polarity, 1),
If(~self.recovery, NextValue(serdes.rx_polarity, 1)),
_12_ms_timer.wait.eq(0),
NextValue(rx_ts2_seen, 0),
NextState("Polling.Configuration")
@ -292,8 +297,10 @@ class PollingFSM(Module):
self.idle.eq(1),
self.rx_ready.eq(1),
self.tx_ready.eq(1),
If(ts_unit.rx_ts1, # FIXME: for bringup, should be Recovery.Active
NextState("Polling.Active")
NextValue(self.recovery, 0),
If(ts_unit.rx_ts1_short, # FIXME: for bringup, should be Recovery.Active
NextValue(self.recovery, 1),
NextState("Recovery.Active")
).Elif(lfps_unit.rx_polling, # FIXME: for bringup
NextState("Polling.Entry")
)
@ -317,6 +324,53 @@ class PollingFSM(Module):
self.exit_to_rx_detect.eq(1)
)
# Recovery ---------------------------------------------------------------------------------
fsm.act("Recovery.Active",
_12_ms_timer.wait.eq(with_timers),
ts_unit.rx_enable.eq(1),
ts_unit.tx_enable.eq(1),
ts_unit.tx_ts1.eq(1),
# Go to RxDetect if no TS1/TS2 seen in the 12ms.
If(_12_ms_timer.done,
NextState("Polling.ExitToRxDetect")
),
# Go to Configuration if at least 8 consecutive TS1 or TS2 seen (8 ensured by ts_unit)
If(ts_unit.rx_ts1,
_12_ms_timer.wait.eq(0),
NextValue(rx_ts2_seen, 0),
NextState("Recovery.Configuration")
),
If(ts_unit.rx_ts2,
_12_ms_timer.wait.eq(0),
NextValue(rx_ts2_seen, 0),
NextState("Recovery.Configuration")
),
)
fsm.act("Recovery.Configuration",
_6_ms_timer.wait.eq(with_timers),
ts_unit.rx_enable.eq(1),
ts_unit.tx_enable.eq(1),
ts_unit.tx_ts2.eq(1),
self.rx_ready.eq(rx_ts2_seen),
NextValue(rx_ts2_seen, rx_ts2_seen | ts_unit.rx_ts2),
# Go to RxDetect if no TS2 seen in the 6ms.
If(_6_ms_timer.done,
_6_ms_timer.wait.eq(0),
NextState("Polling.ExitToRxDetect")
),
# Go to Idle when:
# - 8 consecutive TS2 ordered sets are received. (8 ensured by ts_unit)
# - 16 TS2 ordered sets are sent after receiving the first 8 TS2 ordered sets. FIXME
If(ts_unit.tx_done,
If(rx_ts2_seen,
NextState("Polling.Idle")
)
)
)
# Link Training and Status State Machine -----------------------------------------------------------
class LTSSM(Module):