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Merged
ruck314 merged 1 commit into from
Aug 24, 2026
Merged

Harden RSSI connection negotiation #1457

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123 changes: 83 additions & 40 deletions protocols/rssi/v1/rtl/RssiConnFsm.vhd
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Original file line number Diff line number Diff line change
Expand Up @@ -40,7 +40,7 @@ entity RssiConnFsm is
--
WINDOW_ADDR_SIZE_G : positive := 3;
SEGMENT_ADDR_SIZE_G : positive := 7 -- 2^SEGMENT_ADDR_SIZE_G = Number of 64 bit wide data words
);
);
port (
clk_i : in sl;
rst_i : in sl;
Expand Down Expand Up @@ -95,10 +95,11 @@ entity RssiConnFsm is
-- Status signals
peerTout_o : out sl;
paramReject_o : out sl
);
);
end entity RssiConnFsm;

architecture rtl of RssiConnFsm is

--
constant SAMPLES_PER_TIME_C : integer := integer(TIMEOUT_UNIT_G * CLK_FREQUENCY_G);
--
Expand All @@ -112,7 +113,7 @@ architecture rtl of RssiConnFsm is
WAIT_ACK_S,
SEND_RST_S,
OPEN_S
);
);

type RegType is record
connActive : sl;
Expand All @@ -136,7 +137,6 @@ architecture rtl of RssiConnFsm is
---
state : StateType;
connState : slv(3 downto 0);

end record RegType;

constant REG_INIT_C : RegType := (
Expand Down Expand Up @@ -165,6 +165,42 @@ architecture rtl of RssiConnFsm is
signal r : RegType := REG_INIT_C;
signal rin : RegType;

function validPeerParams(param : RssiParamType) return boolean is
begin
return (
param.maxOutsSeg /= 0 and
conv_integer(param.maxSegSize) >= 8 and
param.retransTout /= 0 and
param.cumulAckTout /= 0 and
param.nullSegTout /= 0);
end function validPeerParams;

function clampWindowSize(value : slv(7 downto 0)) return integer is
variable size : integer;
begin
size := conv_integer(value);
if (size < 1) then
return 1;
elsif (size > 2 ** WINDOW_ADDR_SIZE_G) then
return 2 ** WINDOW_ADDR_SIZE_G;
else
return size;
end if;
end function clampWindowSize;

function clampBufferSize(value : slv(15 downto 0)) return integer is
variable size : integer;
begin
size := conv_integer(value(15 downto 3)); -- Divide by 8
if (size < 1) then
return 1;
elsif (size > 2 ** SEGMENT_ADDR_SIZE_G) then
return 2 ** SEGMENT_ADDR_SIZE_G;
else
return size;
end if;
end function clampBufferSize;



begin
Expand Down Expand Up @@ -234,34 +270,37 @@ begin
v.sndAck := '0';
v.sndRst := '0';
v.txAckF := '0';
v.timeoutCntr := r.timeoutCntr + 1;
if (r.timeoutCntr /= RETRANS_TOUT_G * SAMPLES_PER_TIME_C) then
v.timeoutCntr := r.timeoutCntr + 1;
end if;
--
if (rxValid_i = '1' and rxFlags_i.syn = '1' and rxFlags_i.ack = '1') then
-- Check parameters
if (
rxRssiParam_i.version = appRssiParam_i.version and -- Version match
rxRssiParam_i.chksumEn = appRssiParam_i.chksumEn and -- Checksum match
rxRssiParam_i.timeoutUnit = appRssiParam_i.timeoutUnit -- Timeout unit match
rxRssiParam_i.timeoutUnit = appRssiParam_i.timeoutUnit and -- Timeout unit match
validPeerParams(rxRssiParam_i) = true
) then

-- Accept the parameters from the server
v.rssiParam := rxRssiParam_i;

-- Autoneg the maxOutsSeg
if (rxRssiParam_i.maxOutsSeg > appRssiParam_i.maxOutsSeg) then
v.txWindowSize := conv_integer(appRssiParam_i.maxOutsSeg);
v.txWindowSize := clampWindowSize(appRssiParam_i.maxOutsSeg);
v.rssiParam.maxOutsSeg := appRssiParam_i.maxOutsSeg;
else
v.txWindowSize := conv_integer(rxRssiParam_i.maxOutsSeg);
v.txWindowSize := clampWindowSize(rxRssiParam_i.maxOutsSeg);
v.rssiParam.maxOutsSeg := rxRssiParam_i.maxOutsSeg;
end if;

-- Autoneg the maxSegSize
if (rxRssiParam_i.maxSegSize > appRssiParam_i.maxSegSize) then
v.txBufferSize := conv_integer(appRssiParam_i.maxSegSize(15 downto 3)); -- Divide by 8
v.txBufferSize := clampBufferSize(appRssiParam_i.maxSegSize);
v.rssiParam.maxSegSize := appRssiParam_i.maxSegSize;
else
v.txBufferSize := conv_integer(rxRssiParam_i.maxSegSize(15 downto 3)); -- Divide by 8
v.txBufferSize := clampBufferSize(rxRssiParam_i.maxSegSize);
v.rssiParam.maxSegSize := rxRssiParam_i.maxSegSize;
end if;

Expand Down Expand Up @@ -327,43 +366,43 @@ begin
--
if (rxValid_i = '1' and rxFlags_i.syn = '1') then

-- Accept the parameters from the client
v.rssiParam := rxRssiParam_i;

-- Autoneg the maxOutsSeg
if (rxRssiParam_i.maxOutsSeg > appRssiParam_i.maxOutsSeg) then
v.txWindowSize := conv_integer(appRssiParam_i.maxOutsSeg);
v.rssiParam.maxOutsSeg := appRssiParam_i.maxOutsSeg;
else
v.txWindowSize := conv_integer(rxRssiParam_i.maxOutsSeg);
v.rssiParam.maxOutsSeg := rxRssiParam_i.maxOutsSeg;
end if;

-- Autoneg the maxSegSize
if (rxRssiParam_i.maxSegSize > appRssiParam_i.maxSegSize) then
v.txBufferSize := conv_integer(appRssiParam_i.maxSegSize(15 downto 3)); -- Divide by 8
v.rssiParam.maxSegSize := appRssiParam_i.maxSegSize;
else
v.txBufferSize := conv_integer(rxRssiParam_i.maxSegSize(15 downto 3)); -- Divide by 8
v.rssiParam.maxSegSize := rxRssiParam_i.maxSegSize;
end if;

--
v.paramReject := '0';

-- Check parameters that have to match
if (
rxRssiParam_i.version /= appRssiParam_i.version or -- Version equality
rxRssiParam_i.chksumEn /= appRssiParam_i.chksumEn or -- Checksum match
rxRssiParam_i.timeoutUnit /= appRssiParam_i.timeoutUnit -- Timeout unit match
rxRssiParam_i.timeoutUnit /= appRssiParam_i.timeoutUnit or -- Timeout unit match
validPeerParams(rxRssiParam_i) = false
) then

-- Propose different parameters (overwrite)
v.rssiParam.version := appRssiParam_i.version;
v.rssiParam.timeoutUnit := appRssiParam_i.timeoutUnit;
v.rssiParam.chksumEn := appRssiParam_i.chksumEn;
v.rssiParam := appRssiParam_i;
v.txWindowSize := clampWindowSize(appRssiParam_i.maxOutsSeg);
v.txBufferSize := clampBufferSize(appRssiParam_i.maxSegSize);
--
v.paramReject := '1';
v.paramReject := '1';
else
-- Accept the parameters from the client
v.rssiParam := rxRssiParam_i;

-- Autoneg the maxOutsSeg
if (rxRssiParam_i.maxOutsSeg > appRssiParam_i.maxOutsSeg) then
v.txWindowSize := clampWindowSize(appRssiParam_i.maxOutsSeg);
v.rssiParam.maxOutsSeg := appRssiParam_i.maxOutsSeg;
else
v.txWindowSize := clampWindowSize(rxRssiParam_i.maxOutsSeg);
v.rssiParam.maxOutsSeg := rxRssiParam_i.maxOutsSeg;
end if;

-- Autoneg the maxSegSize
if (rxRssiParam_i.maxSegSize > appRssiParam_i.maxSegSize) then
v.txBufferSize := clampBufferSize(appRssiParam_i.maxSegSize);
v.rssiParam.maxSegSize := appRssiParam_i.maxSegSize;
else
v.txBufferSize := clampBufferSize(rxRssiParam_i.maxSegSize);
v.rssiParam.maxSegSize := rxRssiParam_i.maxSegSize;
end if;

v.paramReject := '0';
end if;
-- Go to ACK state
v.state := SEND_SYN_ACK_S;
Expand Down Expand Up @@ -398,7 +437,9 @@ begin
v.txAckF := '0';
v.paramReject := '0';
--
v.timeoutCntr := r.timeoutCntr+1;
if (r.timeoutCntr /= RETRANS_TOUT_G * SAMPLES_PER_TIME_C) then
v.timeoutCntr := r.timeoutCntr + 1;
end if;

--
v.rssiParam := r.rssiParam;
Expand Down Expand Up @@ -507,5 +548,7 @@ begin
connState_o <= r.connState;
peerTout_o <= r.peerTout;
paramReject_o <= r.paramReject;

---------------------------------------------------------------------

end architecture rtl;
5 changes: 1 addition & 4 deletions tests/protocols/rssi/test_RssiConnFsm.py
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Original file line number Diff line number Diff line change
Expand Up @@ -37,7 +37,7 @@
import pytest
from cocotb.triggers import Timer

from tests.common.regression_utils import env_flag, run_surf_vhdl_test
from tests.common.regression_utils import run_surf_vhdl_test
from tests.protocols.rssi.rssi_test_utils import RssiParams
from tests.protocols.ssi.ssi_test_utils import (
cycle as ssi_cycle,
Expand Down Expand Up @@ -422,10 +422,7 @@ async def client_retries_syn_then_times_out_waiting_for_syn_ack_test(dut):
pytest.param({"SERVER_G": False}, id="client"),
]

KNOWN_ISSUE_REASON = "set RUN_RSSI_KNOWN_ISSUE_TESTS=1 to run RSSI cases that require follow-up RTL fixes"


@pytest.mark.skipif(not env_flag("RUN_RSSI_KNOWN_ISSUE_TESTS", default=False), reason=KNOWN_ISSUE_REASON)
@pytest.mark.parametrize("parameters", PARAMETER_SWEEP)
def test_RssiConnFsm(parameters):
run_surf_vhdl_test(
Expand Down