Files
FPGA-Neural/sim/graph_format_tb.v
T
micheleandClaude Sonnet 5 55c827bedf feat: PSRAM page-mode reads + graph engine (Type #2) + real pinout/IRQ pins
PSRAM page-mode read burst support in psram_controller.v: enables the
ISSI IS66WVE4M16EBLL-70BLI's page mode via its configuration-register
software-access sequence at boot (disabled by default on the real
chip), then keeps CE#/OE# asserted after a read so a same-page
continuation only pays tAPA (20ns) instead of a full tAA (70ns)
random access, with automatic tCEM-safe session closing. Only a WRITE
closes the page -- byte-enable changes do not, since
int8_memory_access.v alternates them on nearly every access and an
early implementation attempt that treated them as a close condition
measured a real regression (53.25->61.25 cycles/edge) before being
corrected (53.25->37.53 cycles/edge, +42% gather bandwidth).
sim/psram_model.v gained independent tAPA/tAA and tCEM enforcement
(with a real Verilog same-timestep event-ordering race found and
fixed via a #0 sync) so the regression proves real timing compliance,
not just data correctness. New sim/psram_page_mode_tb.v; full 26-file
regression suite re-run clean. Real nextpnr-ecp5 Fmax re-measured on
the full spi_neuron_top system: 75.73MHz (P2, up from 55.59MHz) and
65.13MHz (P8) -- still under the 80MHz target but not regressed, with
the critical path confirmed (not assumed) to remain entirely inside
neuron_parallel's accumulate chain, never psram_controller.

Also includes this session's other already-validated work: the graph
engine (Type #2 sparse-graph network: act_buffer, graph_engine,
netasm host assembler), real CABGA381 pinout (.lpf, place&route
verified) and physical IRQ_N/DATA_READY_N pins, and Phase 7 timing
closure logs -- all previously uncommitted, documented in WORKLOG.md.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01LH3jPeJ3eFMfF2v8SQhpkk
2026-09-03 17:12:05 +02:00

299 lines
11 KiB
Verilog

`timescale 1ns/1ps
// ================================================================
// GRAPH FORMAT TESTBENCH (Phase G2)
//
// Validates the Type #2 (graph) on-disk data format from §4.2/§4.3
// of the spec, byte-exact, through the REAL memory stack
// (int8_memory_access + memory_interface + psram_controller +
// psram_model) -- same harness as sim/int8_psram_integration_tb.v.
// No new RTL: this phase is about the FORMAT, not new hardware.
//
// Graph under test is the worked example from §3:
// 4 inputs (id 0..3). n4 = f(x0*5 + x1*(-3) + bias=2), relu.
// n5 = f(act[n4]*2 + x2*7 + bias=0), none. output = n5 (id 5).
//
// Graph descriptor table (11 bytes/entry, MSB-first, entries in
// out_id order) at table_base = 0x000000:
// entry0 (n4, out_id=4): conn_ptr=0x000100 n_conn=2 out_id=4
// activation=ACT_RELU(1) bias=2 reserved=0
// entry1 (n5, out_id=5): conn_ptr=0x000108 n_conn=2 out_id=5
// activation=ACT_NONE(0) bias=0 reserved=0
//
// Edge blocks (4 bytes/edge: src_id uint16 BE, weight int8,
// reserved=0):
// n4 @ 0x000100: (src=0,w=5), (src=1,w=-3)
// n5 @ 0x000108: (src=4,w=2), (src=2,w=7)
// ================================================================
module tb;
localparam ADDR_WIDTH = 23;
localparam DATA_WIDTH = 16;
localparam CLK_PERIOD = 12.5; // 80 MHz
localparam ACT_NONE = 8'd0;
localparam ACT_RELU = 8'd1;
reg clk;
reg rst;
reg req;
reg wr;
reg [ADDR_WIDTH-1:0] addr;
reg signed [7:0] wdata;
wire signed [7:0] rdata;
wire ready;
wire mem_req;
wire mem_wr;
wire [ADDR_WIDTH-1:0] mem_addr;
wire [DATA_WIDTH-1:0] mem_wdata;
wire mem_lb_n;
wire mem_ub_n;
wire [DATA_WIDTH-1:0] mem_rdata;
wire mem_ready;
wire psram_mem_req;
wire psram_mem_wr;
wire [ADDR_WIDTH-1:0] psram_mem_addr;
wire [DATA_WIDTH-1:0] psram_mem_wdata;
wire psram_mem_lb_n;
wire psram_mem_ub_n;
wire [DATA_WIDTH-1:0] psram_mem_rdata;
wire psram_mem_ready;
wire [ADDR_WIDTH-1:0] psram_a;
wire [DATA_WIDTH-1:0] psram_dq;
wire psram_ce_n;
wire psram_oe_n;
wire psram_we_n;
wire psram_lb_n;
wire psram_ub_n;
wire psram_zz_n;
int8_memory_access #(
.ADDR_WIDTH(ADDR_WIDTH)
) int8_access (
.clk(clk), .rst(rst),
.req(req), .wr(wr), .addr(addr), .wdata(wdata),
.rdata(rdata), .ready(ready),
.mem_req(mem_req), .mem_wr(mem_wr), .mem_addr(mem_addr),
.mem_wdata(mem_wdata), .mem_lb_n(mem_lb_n), .mem_ub_n(mem_ub_n),
.mem_rdata(mem_rdata), .mem_ready(mem_ready)
);
memory_interface #(
.ADDR_WIDTH(ADDR_WIDTH), .DATA_WIDTH(DATA_WIDTH)
) memory_if (
.clk(clk), .rst(rst),
.req(mem_req), .wr(mem_wr), .addr(mem_addr), .wdata(mem_wdata),
.lb_n(mem_lb_n), .ub_n(mem_ub_n),
.rdata(mem_rdata), .ready(mem_ready),
.mem_req(psram_mem_req), .mem_wr(psram_mem_wr), .mem_addr(psram_mem_addr),
.mem_wdata(psram_mem_wdata), .mem_lb_n(psram_mem_lb_n), .mem_ub_n(psram_mem_ub_n),
.mem_rdata(psram_mem_rdata), .mem_ready(psram_mem_ready)
);
psram_controller #(
.ADDR_WIDTH(ADDR_WIDTH), .DATA_WIDTH(DATA_WIDTH), .CLK_FREQ_MHZ(80)
) psram_ctrl (
.clk(clk), .rst(rst),
.mem_req(psram_mem_req), .mem_wr(psram_mem_wr), .mem_addr(psram_mem_addr),
.mem_wdata(psram_mem_wdata), .mem_lb_n(psram_mem_lb_n), .mem_ub_n(psram_mem_ub_n),
.mem_rdata(psram_mem_rdata), .mem_ready(psram_mem_ready),
.psram_a(psram_a), .psram_dq(psram_dq),
.psram_ce_n(psram_ce_n), .psram_oe_n(psram_oe_n), .psram_we_n(psram_we_n),
.psram_lb_n(psram_lb_n), .psram_ub_n(psram_ub_n), .psram_zz_n(psram_zz_n)
);
psram_model #(
.ADDR_WIDTH(ADDR_WIDTH), .DATA_WIDTH(DATA_WIDTH), .DEPTH(16384)
) psram (
.clk(clk), .a(psram_a), .dq(psram_dq),
.ce_n(psram_ce_n), .oe_n(psram_oe_n), .we_n(psram_we_n),
.lb_n(psram_lb_n), .ub_n(psram_ub_n), .zz_n(psram_zz_n)
);
initial begin
clk = 1'b0;
forever #(CLK_PERIOD / 2.0) clk = ~clk;
end
integer errors;
task write_byte(input [ADDR_WIDTH-1:0] byte_addr, input [7:0] data);
begin
@(posedge clk);
addr <= byte_addr;
wdata <= $signed(data);
wr <= 1'b1;
req <= 1'b1;
@(posedge clk);
req <= 1'b0;
wait (ready);
@(posedge clk);
end
endtask
task read_byte(input [ADDR_WIDTH-1:0] byte_addr, input [7:0] expected, input [255:0] name);
begin
@(posedge clk);
addr <= byte_addr;
wr <= 1'b0;
req <= 1'b1;
@(posedge clk);
req <= 1'b0;
wait (ready);
if (rdata !== $signed(expected)) begin
$display("FAIL %0s addr=0x%06x expected=0x%02x got=0x%02x", name, byte_addr, expected, rdata);
errors = errors + 1;
end else begin
$display("PASS %0s addr=0x%06x data=0x%02x", name, byte_addr, rdata);
end
@(posedge clk);
end
endtask
// §4.2 graph descriptor entry: 11 bytes, MSB-first.
task write_graph_desc(
input [ADDR_WIDTH-1:0] base,
input [23:0] conn_ptr,
input [15:0] n_conn,
input [15:0] out_id,
input [7:0] activation,
input [7:0] bias
);
begin
write_byte(base + 0, conn_ptr[23:16]);
write_byte(base + 1, conn_ptr[15:8]);
write_byte(base + 2, conn_ptr[7:0]);
write_byte(base + 3, n_conn[15:8]);
write_byte(base + 4, n_conn[7:0]);
write_byte(base + 5, out_id[15:8]);
write_byte(base + 6, out_id[7:0]);
write_byte(base + 7, activation);
write_byte(base + 8, bias);
write_byte(base + 9, 8'h00); // reserved
write_byte(base + 10, 8'h00); // reserved
end
endtask
// §4.3 edge: 4 bytes, src_id uint16 BE, weight int8, reserved.
task write_edge(
input [ADDR_WIDTH-1:0] base,
input [15:0] src_id,
input [7:0] weight
);
begin
write_byte(base + 0, src_id[15:8]);
write_byte(base + 1, src_id[7:0]);
write_byte(base + 2, weight);
write_byte(base + 3, 8'h00); // reserved
end
endtask
localparam TABLE_BASE = 23'h000000;
localparam N4_EDGES = 23'h000100;
localparam N5_EDGES = 23'h000108;
initial begin
errors = 0;
req = 1'b0; wr = 1'b0; addr = 0; wdata = 0;
rst = 1'b1;
repeat (5) @(posedge clk);
rst = 1'b0;
wait (psram_ctrl.state == psram_ctrl.STATE_IDLE);
$display("");
$display("========================================");
$display("GRAPH FORMAT (Type #2) BYTE-EXACT TEST");
$display("========================================");
$display("");
// ---- write the descriptor table (2 entries) ----
write_graph_desc(TABLE_BASE + 0*11, N4_EDGES, 16'd2, 16'd4, ACT_RELU, 8'sd2);
write_graph_desc(TABLE_BASE + 1*11, N5_EDGES, 16'd2, 16'd5, ACT_NONE, 8'sd0);
// ---- write the edge blocks ----
write_edge(N4_EDGES + 0*4, 16'd0, 8'sd5);
write_edge(N4_EDGES + 1*4, 16'd1, -8'sd3);
write_edge(N5_EDGES + 0*4, 16'd4, 8'sd2);
write_edge(N5_EDGES + 1*4, 16'd2, 8'sd7);
$display("-- write phase done, reading back byte-exact --");
$display("");
// ---- read back entry 0 (n4) byte-exact ----
read_byte(TABLE_BASE+0, 8'h00, "n4.conn_ptr[23:16]");
read_byte(TABLE_BASE+1, 8'h01, "n4.conn_ptr[15:8]");
read_byte(TABLE_BASE+2, 8'h00, "n4.conn_ptr[7:0]");
read_byte(TABLE_BASE+3, 8'h00, "n4.n_conn[15:8]");
read_byte(TABLE_BASE+4, 8'h02, "n4.n_conn[7:0]");
read_byte(TABLE_BASE+5, 8'h00, "n4.out_id[15:8]");
read_byte(TABLE_BASE+6, 8'h04, "n4.out_id[7:0]");
read_byte(TABLE_BASE+7, ACT_RELU, "n4.activation");
read_byte(TABLE_BASE+8, 8'h02, "n4.bias");
read_byte(TABLE_BASE+9, 8'h00, "n4.reserved0");
read_byte(TABLE_BASE+10, 8'h00, "n4.reserved1");
// ---- read back entry 1 (n5) byte-exact ----
read_byte(TABLE_BASE+11, 8'h00, "n5.conn_ptr[23:16]");
read_byte(TABLE_BASE+12, 8'h01, "n5.conn_ptr[15:8]");
read_byte(TABLE_BASE+13, 8'h08, "n5.conn_ptr[7:0]");
read_byte(TABLE_BASE+14, 8'h00, "n5.n_conn[15:8]");
read_byte(TABLE_BASE+15, 8'h02, "n5.n_conn[7:0]");
read_byte(TABLE_BASE+16, 8'h00, "n5.out_id[15:8]");
read_byte(TABLE_BASE+17, 8'h05, "n5.out_id[7:0]");
read_byte(TABLE_BASE+18, ACT_NONE, "n5.activation");
read_byte(TABLE_BASE+19, 8'h00, "n5.bias");
read_byte(TABLE_BASE+20, 8'h00, "n5.reserved0");
read_byte(TABLE_BASE+21, 8'h00, "n5.reserved1");
// ---- read back n4's edges byte-exact ----
read_byte(N4_EDGES+0, 8'h00, "n4.e0.src_id[15:8]");
read_byte(N4_EDGES+1, 8'h00, "n4.e0.src_id[7:0]");
read_byte(N4_EDGES+2, 8'h05, "n4.e0.weight");
read_byte(N4_EDGES+3, 8'h00, "n4.e0.reserved");
read_byte(N4_EDGES+4, 8'h00, "n4.e1.src_id[15:8]");
read_byte(N4_EDGES+5, 8'h01, "n4.e1.src_id[7:0]");
read_byte(N4_EDGES+6, 8'hFD, "n4.e1.weight(-3)");
read_byte(N4_EDGES+7, 8'h00, "n4.e1.reserved");
// ---- read back n5's edges byte-exact ----
read_byte(N5_EDGES+0, 8'h00, "n5.e0.src_id[15:8]");
read_byte(N5_EDGES+1, 8'h04, "n5.e0.src_id[7:0]");
read_byte(N5_EDGES+2, 8'h02, "n5.e0.weight");
read_byte(N5_EDGES+3, 8'h00, "n5.e0.reserved");
read_byte(N5_EDGES+4, 8'h00, "n5.e1.src_id[15:8]");
read_byte(N5_EDGES+5, 8'h02, "n5.e1.src_id[7:0]");
read_byte(N5_EDGES+6, 8'h07, "n5.e1.weight");
read_byte(N5_EDGES+7, 8'h00, "n5.e1.reserved");
// ---- overlap/independence sanity check: rewriting n4's
// bias must not disturb n5's descriptor or any edge byte ----
write_byte(TABLE_BASE+8, 8'sd9);
read_byte(TABLE_BASE+8, 8'h09, "n4.bias overwritten");
read_byte(TABLE_BASE+19, 8'h00, "n5.bias unaffected by n4 rewrite");
read_byte(N4_EDGES+2, 8'h05, "n4.e0.weight unaffected by n4 desc rewrite");
$display("");
if (errors == 0) begin
$display("========================================");
$display("GRAPH FORMAT TEST PASSED (0 errors)");
$display("========================================");
end else begin
$display("========================================");
$display("GRAPH FORMAT TEST FAILED (%0d errors)", errors);
$display("========================================");
$fatal;
end
$finish;
end
endmodule