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core/arp: Move ARP cache logic to LiteEthARPCache and define interfaces.

This commit is contained in:
Florent Kermarrec 2023-07-31 14:46:16 +02:00
parent fba8925f60
commit dc7ed0de6f
1 changed files with 61 additions and 33 deletions
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94
liteeth/core/arp.py
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@ -154,6 +154,47 @@ class LiteEthARPRX(LiteXModule):
)
)
# ARP Cache ----------------------------------------------------------------------------------------
class LiteEthARPCache(LiteXModule):
def __init__(self, entries, clk_freq):
assert entries == 1
# Update interface.
self.update = stream.Endpoint([("ip_address", 32), ("mac_address", 48)])
# Request/Response interface.
self.request = stream.Endpoint([("ip_address", 32)])
self.response = stream.Endpoint([("mac_address", 48), ("error", 1)])
# # #
# Note: Store only 1 IP/MAC couple, can be improved with a real
# table in the future to improve performance when packets are
# targeting multiple destinations.
cached_valid = Signal()
cached_ip_address = Signal(32, reset_less=True)
cached_mac_address = Signal(48, reset_less=True)
self.cached_timer = WaitTimer(int(clk_freq*10))
self.comb += self.update.ready.eq(1)
self.sync += [
If(self.update.valid,
cached_valid.eq(1),
cached_ip_address.eq(self.update.ip_address),
cached_mac_address.eq(self.update.mac_address),
).Else(
If(self.cached_timer.done,
cached_valid.eq(0)
)
)
]
self.comb += self.cached_timer.wait.eq(~self.update.valid)
self.comb += self.request.ready.eq(1)
self.comb += self.response.valid.eq(self.request.valid)
self.comb += self.response.error.eq(~cached_valid | (self.request.ip_address != cached_ip_address))
self.comb += self.response.mac_address.eq(cached_mac_address)
# ARP Table ----------------------------------------------------------------------------------------
class LiteEthARPTable(LiteXModule):
@ -174,27 +215,7 @@ class LiteEthARPTable(LiteXModule):
self.request_timer = WaitTimer(100e-3*clk_freq)
self.comb += self.request_timer.wait.eq(request_pending & ~self.request_timer.done)
# Note: Store only 1 IP/MAC couple, can be improved with a real
# table in the future to improve performance when packets are
# targeting multiple destinations.
cached_update = Signal()
cached_valid = Signal()
cached_ip_address = Signal(32, reset_less=True)
cached_mac_address = Signal(48, reset_less=True)
cached_timer = WaitTimer(100e-3*clk_freq)
self.submodules += cached_timer
self.sync += [
If(cached_update,
cached_valid.eq(1),
cached_ip_address.eq(sink.ip_address),
cached_mac_address.eq(sink.mac_address),
).Else(
If(cached_timer.done,
cached_valid.eq(0)
)
)
]
self.comb += cached_timer.wait.eq(~cached_update)
self.cache = cache = LiteEthARPCache(entries=1, clk_freq=clk_freq)
self.fsm = fsm = FSM(reset_state="IDLE")
fsm.act("IDLE",
@ -221,9 +242,13 @@ class LiteEthARPTable(LiteXModule):
)
fsm.act("UPDATE_TABLE",
If(request_pending & (request_ip_address == sink.ip_address),
cached_update.eq(1),
NextValue(request_pending, 0),
NextState("PRESENT_RESPONSE")
cache.update.valid.eq(1),
cache.update.ip_address.eq(sink.ip_address),
cache.update.mac_address.eq(sink.mac_address),
If(cache.update.ready,
NextValue(request_pending, 0),
NextState("PRESENT_RESPONSE")
)
).Else(
NextState("IDLE")
)
@ -239,15 +264,18 @@ class LiteEthARPTable(LiteXModule):
)
)
fsm.act("CHECK_TABLE",
If(cached_valid & (request.ip_address == cached_ip_address),
request.ready.eq(request.valid),
NextState("PRESENT_RESPONSE"),
).Else(
cache.request.valid.eq(1),
cache.request.ip_address.eq(request.ip_address),
If(cache.response.valid,
request.ready.eq(1),
NextValue(request_counter, 0),
NextValue(request_pending, 1),
NextValue(request_ip_address, request.ip_address),
NextState("SEND_REQUEST")
If(cache.response.error,
NextValue(request_counter, 0),
NextValue(request_pending, 1),
NextValue(request_ip_address, request.ip_address),
NextState("SEND_REQUEST")
).Else(
NextState("PRESENT_RESPONSE"),
)
)
)
fsm.act("SEND_REQUEST",
@ -261,7 +289,7 @@ class LiteEthARPTable(LiteXModule):
)
fsm.act("PRESENT_RESPONSE",
response.valid.eq(1),
response.mac_address.eq(cached_mac_address),
response.mac_address.eq(cache.response.mac_address),
If(response.ready,
NextValue(response.failed, 0),
NextState("IDLE")