feat(hw): add banked CAM pipeline with grouped read/write noise

- Add cam_core_banked.sv with 8-lane banked CAM core
- Add cam_write_noise.sv and cam_read_noise.sv for grouped noise injection
- Add noise_mask_grouped.sv generating grouped flip masks from 128-bit PRNG
- Add match_engine_pipeline.sv with multi-stage pipelined top-1 selection
- Add popcount_pipeline.sv for pipelined popcount operations
- Refactor test_cam_basic.py with parametrized DUT introspection helpers
- Add Python ref_model match_top1_with_read_noise() for read noise verification
- Update Makefile with separate WRITE_NOISE_* and READ_NOISE_* parameter groups
- Add new testbenches: test_cam_core_banked, test_cam_read_noise,
  test_cam_write_noise, test_match_engine_pipeline, test_ref_model_noise
  
breaking change hint: NUM_ROWS default changed from 512→4096, LANES from 16→8
This commit is contained in:
2026-05-13 16:21:27 +08:00
parent c41e64d1c6
commit 8f59a287c4
17 changed files with 1331 additions and 384 deletions

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@@ -1,189 +1,95 @@
`timescale 1ns / 1ps
`include "cam_params.svh"
// Design constraints:
// HASH_BITS % NOISE_BITS == 0
// GROUP_BITS (= HASH_BITS / NOISE_BITS) == 64 (needed for 6-bit index)
// NOISE_BITS * GROUP_RAND_BITS <= 128
// 0 <= NOISE_RATE_NUM <= NOISE_RATE_DEN
// NOISE_RATE_DEN > 0
// NOISE_SEED != 64'd0
// NOISE_BITS > 0
module cam_noisy #(
parameter bit NOISE_EN = 1'b1,
parameter int NOISE_RATE_NUM = 70,
parameter int NOISE_RATE_DEN = 100,
parameter logic [63:0] NOISE_SEED = 64'hB504_F32D_B504_F32D,
parameter int NOISE_BITS = 8
parameter bit WRITE_NOISE_EN = 1'b1,
parameter int WRITE_NOISE_RATE_NUM = 1,
parameter int WRITE_NOISE_RATE_DEN = 100,
parameter int WRITE_NOISE_BITS = 8,
parameter logic [63:0] WRITE_NOISE_SEED = 64'hB504_F32D_B504_F32D,
parameter bit READ_NOISE_EN = 1'b1,
parameter int READ_NOISE_RATE_NUM = 1,
parameter int READ_NOISE_RATE_DEN = 100,
parameter int READ_NOISE_BITS = 8,
parameter logic [63:0] READ_NOISE_SEED = 64'h6A09_E667_F3BC_C909
) (
input logic clk,
input logic rst_n,
// Write interface (handshake)
input logic wr_valid,
output logic wr_ready,
input logic [ (`ROW_BITS)-1:0] wr_addr,
input logic [(`HASH_BITS)-1:0] write_hash,
// Read interface (passthrough to cam_core, combinational read)
input logic [ (`LANES)*(`ROW_BITS)-1:0] rd_addr_lanes_flat,
output logic [(`LANES)*(`HASH_BITS)-1:0] rd_hash_lanes_flat
input logic clk,
input logic rst_n,
input logic wr_valid,
output logic wr_ready,
input logic [(`ROW_BITS)-1:0] wr_addr,
input logic [(`HASH_BITS)-1:0] write_hash,
input logic rd_valid_i,
input logic [(`ROW_BITS)-1:0] rd_base_row_i,
output logic rd_valid_o,
output logic [(`LANES)*(`ROW_BITS)-1:0] rd_row_ids_o,
output logic [(`LANES)*(`HASH_BITS)-1:0] rd_hashes_o,
output logic [(`LANES)-1:0] rd_lane_valid_o
);
// ── Local parameters ──
localparam int GROUP_BITS = `HASH_BITS / NOISE_BITS;
localparam int BIT_INDEX_BITS = 6;
localparam int SAMPLE_BITS = 8;
localparam int GROUP_RAND_BITS = BIT_INDEX_BITS + SAMPLE_BITS; // 14
localparam int SAMPLE_RANGE = 2 ** SAMPLE_BITS; // 256
localparam int THRESHOLD = (NOISE_RATE_NUM * SAMPLE_RANGE) / NOISE_RATE_DEN;
// ── Elaboration-time parameter checks ──
initial begin
if (NOISE_BITS <= 0)
$fatal(1, "NOISE_BITS must be > 0, got %0d", NOISE_BITS);
if (`HASH_BITS % NOISE_BITS != 0)
$fatal(1, "HASH_BITS (%0d) must be divisible by NOISE_BITS (%0d)", `HASH_BITS, NOISE_BITS);
if (GROUP_BITS != 64)
$fatal(1, "GROUP_BITS (= HASH_BITS/NOISE_BITS) must equal 64 for 6-bit index, got %0d", GROUP_BITS);
if (NOISE_BITS * GROUP_RAND_BITS > 128)
$fatal(1, "NOISE_BITS*GROUP_RAND_BITS must be <= 128, got %0d", NOISE_BITS * GROUP_RAND_BITS);
if (NOISE_RATE_DEN <= 0)
$fatal(1, "NOISE_RATE_DEN must be > 0, got %0d", NOISE_RATE_DEN);
if (NOISE_RATE_NUM < 0 || NOISE_RATE_NUM > NOISE_RATE_DEN)
$fatal(1, "NOISE_RATE_NUM (%0d) must be in [0, NOISE_RATE_DEN=%0d]", NOISE_RATE_NUM, NOISE_RATE_DEN);
if (NOISE_SEED == 64'd0)
$fatal(1, "NOISE_SEED must be nonzero — xorshift128/random128 with zero seed never advances");
end
// ── FSM states ──
typedef enum logic [1:0] {
S_IDLE,
S_GEN_MASK,
S_COMMIT
} state_t;
state_t curr_state, next_state;
// ── Latch registers ──
logic [(`ROW_BITS)-1:0] addr_q;
logic [(`HASH_BITS)-1:0] write_hash_q;
// ── Noise generation ──
logic [(`HASH_BITS)-1:0] flip_mask;
logic [127:0] random_num;
// ── Combinational next-mask helper ──
// Computes flip_mask_next from fresh random_num in one cycle.
logic [(`HASH_BITS)-1:0] flip_mask_next;
always_comb begin
flip_mask_next = '0;
for (int i = 0; i < NOISE_BITS; i++) begin
if (random_num[i * GROUP_RAND_BITS + BIT_INDEX_BITS +: SAMPLE_BITS] < THRESHOLD) begin
flip_mask_next[i * GROUP_BITS + random_num[i * GROUP_RAND_BITS +: BIT_INDEX_BITS]] = 1'b1;
end
end
end
// ── Noisy hash for cam_core write ──
logic [(`HASH_BITS)-1:0] noisy_hash;
assign noisy_hash = write_hash_q ^ flip_mask;
// ── wr_ready: only in IDLE ──
assign wr_ready = (curr_state == S_IDLE);
// ── random128 enable: advance random on accepted noisy write ──
logic random_enable;
assign random_enable = wr_ready && wr_valid && NOISE_EN && (NOISE_RATE_NUM > 0);
// ── FSM block 1: state register ──
always_ff @(posedge clk or negedge rst_n) begin
if (!rst_n) begin
curr_state <= S_IDLE;
end else begin
curr_state <= next_state;
end
end
// ── FSM block 2: next-state logic ──
always_comb begin
next_state = curr_state;
case (curr_state)
S_IDLE: begin
if (wr_valid && wr_ready) begin
if (NOISE_EN && (NOISE_RATE_NUM > 0)) next_state = S_GEN_MASK;
else next_state = S_COMMIT;
end
end
S_GEN_MASK: begin
next_state = S_COMMIT;
end
S_COMMIT: begin
next_state = S_IDLE;
end
default: next_state = S_IDLE;
endcase
end
// ── FSM block 3: state actions / datapath registers ──
always_ff @(posedge clk or negedge rst_n) begin
if (!rst_n) begin
addr_q <= '0;
write_hash_q <= '0;
flip_mask <= '0;
end else begin
case (curr_state)
S_IDLE: begin
flip_mask <= '0;
if (wr_valid && wr_ready) begin
addr_q <= wr_addr;
write_hash_q <= write_hash;
end
end
S_GEN_MASK: begin
flip_mask <= flip_mask_next;
end
S_COMMIT: begin
// Write happens via combinational core_wr_en
end
default: ; // No-op
endcase
end
end
// ── cam_core instance ──
logic core_wr_en;
logic [ (`ROW_BITS)-1:0] core_wr_row;
// ── Intermediate wires between pipeline stages ──
logic core_wr_valid;
logic [(`ROW_BITS)-1:0] core_wr_row;
logic [(`HASH_BITS)-1:0] core_wr_hash;
assign core_wr_en = (curr_state == S_COMMIT);
assign core_wr_row = addr_q;
assign core_wr_hash = noisy_hash;
logic core_rd_valid;
logic [(`LANES)*(`ROW_BITS)-1:0] core_rd_row_ids;
logic [(`LANES)*(`HASH_BITS)-1:0] core_rd_hashes;
logic [(`LANES)-1:0] core_rd_lane_valid;
cam_core u_core (
.clk (clk),
.rst_n (rst_n),
.wr_en (core_wr_en),
.wr_row (core_wr_row),
.wr_hash (core_wr_hash),
.rd_addr_lanes_flat(rd_addr_lanes_flat),
.rd_hash_lanes_flat(rd_hash_lanes_flat)
// ── Write noise pipeline ──
cam_write_noise #(
.WRITE_NOISE_EN (WRITE_NOISE_EN),
.WRITE_NOISE_RATE_NUM (WRITE_NOISE_RATE_NUM),
.WRITE_NOISE_RATE_DEN (WRITE_NOISE_RATE_DEN),
.WRITE_NOISE_BITS (WRITE_NOISE_BITS),
.WRITE_NOISE_SEED (WRITE_NOISE_SEED)
) u_write_noise (
.clk (clk),
.rst_n (rst_n),
.wr_valid (wr_valid),
.wr_ready (wr_ready),
.wr_row (wr_addr),
.wr_hash (write_hash),
.core_wr_valid (core_wr_valid),
.core_wr_row (core_wr_row),
.core_wr_hash (core_wr_hash)
);
// ── Random number generator ──
random128 u_random_128 (
.clk (clk),
.rst_n (rst_n),
.enable(random_enable),
.seed ({NOISE_SEED, NOISE_SEED}),
.out (random_num)
// ── Banked synchronous BRAM storage ──
cam_core_banked u_core_banked (
.clk (clk),
.rst_n (rst_n),
.wr_valid (core_wr_valid),
.wr_ready (),
.wr_row (core_wr_row),
.wr_hash (core_wr_hash),
.rd_valid_i (rd_valid_i),
.rd_base_row_i (rd_base_row_i),
.rd_valid_o (core_rd_valid),
.rd_row_ids_o (core_rd_row_ids),
.rd_hashes_o (core_rd_hashes),
.rd_lane_valid_o (core_rd_lane_valid)
);
// ── Read noise pipeline ──
cam_read_noise #(
.READ_NOISE_EN (READ_NOISE_EN),
.READ_NOISE_RATE_NUM (READ_NOISE_RATE_NUM),
.READ_NOISE_RATE_DEN (READ_NOISE_RATE_DEN),
.READ_NOISE_BITS (READ_NOISE_BITS),
.READ_NOISE_SEED (READ_NOISE_SEED)
) u_read_noise (
.clk (clk),
.rst_n (rst_n),
.valid_i (core_rd_valid),
.row_ids_i (core_rd_row_ids),
.hashes_i (core_rd_hashes),
.lane_valid_i (core_rd_lane_valid),
.valid_o (rd_valid_o),
.row_ids_o (rd_row_ids_o),
.hashes_noisy_o (rd_hashes_o),
.lane_valid_o (rd_lane_valid_o)
);
endmodule