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mac/__init__: Add comments on RX broadcard/filtering and minor cleanups.

This commit is contained in:
Florent Kermarrec 2024-08-19 09:58:53 +02:00
parent 0bb6c53795
commit bfc07e543a
1 changed files with 34 additions and 18 deletions
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52
liteeth/mac/__init__.py
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@ -133,7 +133,7 @@ class LiteEthMACCoreCrossbar(Module):
# HW FIFO -> HW Packetizer -> Depacketizer.
self.comb += [
hw_fifo.source.connect(hw_packetizer.sink),
hw_packetizer.source.connect(depacketizer.sink),
hw_packetizer.source.connect(self.depacketizer.sink),
]
# CPU FIFO -> CPU Packetizer -> Interface.
@ -142,41 +142,57 @@ class LiteEthMACCoreCrossbar(Module):
cpu_packetizer.source.connect(interface.sink),
]
# RX packetizer broadcast.
mac_local = Signal()
mac_bcast = Signal()
mac_mcast4 = Signal()
mac_mcast6 = Signal()
mac_match = Signal()
# RX Packetizer Broadcast Filtering.
mac_local = Signal() # Matches the Hardware MAC address (local).
mac_bcast = Signal() # Matches the Broadcast MAC address (FF:FF:FF:FF:FF:FF).
mac_mcast4 = Signal() # Matches IPv4 Multicast MAC addresses (01:00:5E:XX:XX:XX).
mac_mcast6 = Signal() # Matches IPv6 Multicast MAC addresses (33:33:XX:XX:XX:XX).
mac_valid = Signal() # Matches any of the above MAC types.
self.comb += [
# Hardware MAC address check.
mac_local.eq(hw_mac == depacketizer.source.payload.target_mac),
# Broadcast MAC address check.
mac_bcast.eq( 0xffffffffffff == depacketizer.source.payload.target_mac),
# IPv4 Multicast MAC address check.
mac_mcast4.eq(0x01005e000000 == (depacketizer.source.payload.target_mac & 0xffffff000000)),
# IPV6 Multicat MAC address check.
mac_mcast6.eq(0x333300000000 == (depacketizer.source.payload.target_mac & 0xffff00000000)),
mac_match.eq(mac_local | mac_bcast | mac_mcast4 | mac_mcast6),
# Combine all conditions to determine if the packet should be processed.
mac_valid.eq(mac_local | mac_bcast | mac_mcast4 | mac_mcast6),
# Accept when both FIFOs are ready.
rx_ready.eq(hw_fifo.sink.ready & cpu_fifo.sink.ready),
# Present when ready and Depacketizer valid.
rx_valid.eq(rx_ready & depacketizer.source.valid),
depacketizer.source.connect(hw_fifo.sink, omit={"ready", "valid"}),
# Depacketizer -> HW FIFO/CPU FIFO.
depacketizer.source.connect(hw_fifo.sink, omit={"ready", "valid"}),
depacketizer.source.connect(cpu_fifo.sink, omit={"ready", "valid"}),
depacketizer.source.ready.eq(rx_ready),
hw_fifo.sink.valid.eq(rx_valid & mac_match),
hw_fifo.sink.valid.eq(rx_valid & mac_valid),
cpu_fifo.sink.valid.eq(rx_valid & ~mac_local),
]
else:
# RX broadcast.
# RX Broadcast.
self.comb += [
# Accept when both Interface/Depacketizer are ready.
rx_ready.eq(interface.sink.ready & self.depacketizer.sink.ready),
# Present when ready and Core valid.
rx_valid.eq(rx_ready & core.source.valid),
core.source.connect(interface.sink, omit={"ready", "valid"}),
core.source.connect(self.depacketizer.sink, omit={"ready", "valid"}),
# Core -> Interface/Depacketizer.
core.source.connect(interface.sink, omit={"ready", "valid"}),
core.source.connect(depacketizer.sink, omit={"ready", "valid"}),
core.source.ready.eq(rx_ready),
interface.sink.valid.eq(rx_valid),
self.depacketizer.sink.valid.eq(rx_valid),
]
# TX arbiter.
self.tx_arbiter_fsm = fsm = FSM(reset_state="IDLE")
fsm.act("IDLE",
# TX arbiter FSM.
self.tx_arb_fsm = tx_arb_fsm = FSM(reset_state="IDLE")
tx_arb_fsm.act("IDLE",
If(interface.source.valid,
NextState("WISHBONE")
).Else(
@ -185,13 +201,13 @@ class LiteEthMACCoreCrossbar(Module):
)
),
)
fsm.act("WISHBONE",
tx_arb_fsm.act("WISHBONE",
interface.source.connect(core.sink),
If(core.sink.valid & core.sink.ready & core.sink.last,
NextState("IDLE")
),
)
fsm.act("CROSSBAR",
tx_arb_fsm.act("CROSSBAR",
self.packetizer.source.connect(core.sink),
If(core.sink.valid & core.sink.ready & core.sink.last,
NextState("IDLE")