feat: real DDR3 memory path verified against MIG's own ddr3_model.sv (EXP-0068)

New hardware/v3/rtl/mig_native_adapter.v: adapts this project's
established req/wr/addr/wdata/wmask->rdata/ready/busy contract to the
real MIG 7-series native app interface (app_addr/app_cmd/app_en,
app_wdf_data/app_wdf_mask/app_wdf_wren/app_wdf_end, app_rd_data/
app_rd_data_valid/app_rd_data_end), derived from this project's own
real generated mig_7series_0.v port widths, not assumed. Runs in the
ui_clk domain (MIG's own generated clock becomes this project's
system clock going forward).

Verified against MIG's own real, vendor-shipped DDR3 behavioral model
(ddr3_model.sv) via real Xilinx xsim/xvlog/xelab (UNISIM primitives
in MIG's PHY require this over Verilator): 12/12 write-then-read-back
transactions bit-exact, 0 errors, real JEDEC command sequence observed
(Activate/Write/Read/Precharge). Confirms the app_cmd encoding and
burst/beat sequencing on first real test.

Also adds hardware/v3/rtl/sdram_arbiter_n.v (generalized N-way
arbiter, generalizing EXP-0066's 2-way version for N>2 scaling and a
future host-access requester) -- its own isolated test currently
HANGS, root cause not yet found, do not trust this module yet
(disclosed, not hidden).

Full writeup in hardware/v2/logs/experiments.log EXP-0068.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MUG92aM9m68TRc4rG55BcC
This commit is contained in:
2026-09-17 08:43:22 +02:00
co-authored by Claude Sonnet 5
parent 0589620b58
commit e25e4a1506
5 changed files with 847 additions and 0 deletions
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`timescale 1ps/100fs
// ============================================================
// First real verification of mig_native_adapter.v against the REAL,
// vendor-provided DDR3 behavioral model (ddr3_model.sv, shipped with
// this project's own generated mig_7series_0 IP) -- not a stand-in,
// the actual JEDEC-timed model MIG itself ships for exactly this
// purpose. Confirms the app_cmd encoding, burst/beat sequencing, and
// address unit assumed by mig_native_adapter.v's own header comment
// are correct by real write-then-read-back comparison, not by
// documentation archaeology alone.
//
// Instantiates mig_7series_0_mig (the inner module, NOT the public
// mig_7series_0.v wrapper) directly, with SIM_BYPASS_INIT_CAL="FAST"
// overridden -- mig_7series_0.v's own wrapper hardcodes "OFF" (full
// real calibration, impractically slow for simulation) and does not
// expose this parameter; mig_7series_0_mig.v does. All other
// parameters are left at their defaults, which already ARE this
// project's real generated configuration (DQ_WIDTH=16, MEM_DENSITY=
// 2Gb, MEM_SPEEDGRADE=125, MEM_ADDR_ORDER=BANK_ROW_COLUMN, etc.) --
// not generic MIG defaults.
//
// Clock/reset generation and DDR3 pin wiring (WireDelay pass-through,
// zero propagation delay) mirror this project's own vendor-shipped
// example_design/sim/sim_tb_top.v exactly, per its own real, proven
// pattern -- not re-derived from scratch.
// ============================================================
module tb;
localparam CLKIN_PERIOD = 3225; // ps, matches this project's real MIG config
localparam REFCLK_FREQ = 200.0; // MHz
localparam real REFCLK_PERIOD = (1000000.0/(2*REFCLK_FREQ));
localparam RESET_PERIOD = 200000; // ps
localparam ADDR_WIDTH = 25; // this project's own word-address convention (BURST_LEN=8)
localparam BURST_LEN = 8;
reg sys_rst_n;
wire sys_rst = sys_rst_n; // Active Low, matches mig_7series_0_mig's own default polarity
reg sys_clk_i = 1'b0;
always #(CLKIN_PERIOD/2.0) sys_clk_i = ~sys_clk_i;
reg clk_ref_i = 1'b0;
always #REFCLK_PERIOD clk_ref_i = ~clk_ref_i;
initial begin
sys_rst_n = 1'b0;
#RESET_PERIOD sys_rst_n = 1'b1;
end
// ---- real DDR3 pins ----
wire ddr3_reset_n;
wire [15:0] ddr3_dq_fpga;
wire [1:0] ddr3_dqs_p_fpga, ddr3_dqs_n_fpga;
wire [13:0] ddr3_addr_fpga;
wire [2:0] ddr3_ba_fpga;
wire ddr3_ras_n_fpga, ddr3_cas_n_fpga, ddr3_we_n_fpga;
wire [0:0] ddr3_cke_fpga, ddr3_ck_p_fpga, ddr3_ck_n_fpga, ddr3_cs_n_fpga;
wire [1:0] ddr3_dm_fpga;
wire [0:0] ddr3_odt_fpga;
wire [15:0] ddr3_dq_sdram;
reg [13:0] ddr3_addr_sdram;
reg [2:0] ddr3_ba_sdram;
reg ddr3_ras_n_sdram, ddr3_cas_n_sdram, ddr3_we_n_sdram;
wire [0:0] ddr3_cs_n_sdram;
wire [0:0] ddr3_odt_sdram;
reg [0:0] ddr3_cke_sdram;
wire [1:0] ddr3_dm_sdram;
wire [1:0] ddr3_dqs_p_sdram, ddr3_dqs_n_sdram;
reg [0:0] ddr3_ck_p_sdram, ddr3_ck_n_sdram;
reg [0:0] ddr3_cs_n_sdram_tmp;
reg [1:0] ddr3_dm_sdram_tmp;
reg [0:0] ddr3_odt_sdram_tmp;
always @(*) begin
ddr3_ck_p_sdram <= ddr3_ck_p_fpga;
ddr3_ck_n_sdram <= ddr3_ck_n_fpga;
ddr3_addr_sdram <= ddr3_addr_fpga;
ddr3_ba_sdram <= ddr3_ba_fpga;
ddr3_ras_n_sdram <= ddr3_ras_n_fpga;
ddr3_cas_n_sdram <= ddr3_cas_n_fpga;
ddr3_we_n_sdram <= ddr3_we_n_fpga;
ddr3_cke_sdram <= ddr3_cke_fpga;
end
always @(*) ddr3_cs_n_sdram_tmp <= ddr3_cs_n_fpga;
assign ddr3_cs_n_sdram = ddr3_cs_n_sdram_tmp;
always @(*) ddr3_dm_sdram_tmp <= ddr3_dm_fpga;
assign ddr3_dm_sdram = ddr3_dm_sdram_tmp;
always @(*) ddr3_odt_sdram_tmp <= ddr3_odt_fpga;
assign ddr3_odt_sdram = ddr3_odt_sdram_tmp;
genvar dqwd;
generate
for (dqwd = 0; dqwd < 16; dqwd = dqwd + 1) begin : dq_delay
WireDelay #(.Delay_g(0.00), .Delay_rd(0.00), .ERR_INSERT("OFF")) u_delay_dq (
.A(ddr3_dq_fpga[dqwd]), .B(ddr3_dq_sdram[dqwd]),
.reset(sys_rst_n), .phy_init_done(init_calib_complete)
);
end
endgenerate
genvar dqswd;
generate
for (dqswd = 0; dqswd < 2; dqswd = dqswd + 1) begin : dqs_delay
WireDelay #(.Delay_g(0.00), .Delay_rd(0.00), .ERR_INSERT("OFF")) u_delay_dqs_p (
.A(ddr3_dqs_p_fpga[dqswd]), .B(ddr3_dqs_p_sdram[dqswd]),
.reset(sys_rst_n), .phy_init_done(init_calib_complete)
);
WireDelay #(.Delay_g(0.00), .Delay_rd(0.00), .ERR_INSERT("OFF")) u_delay_dqs_n (
.A(ddr3_dqs_n_fpga[dqswd]), .B(ddr3_dqs_n_sdram[dqswd]),
.reset(sys_rst_n), .phy_init_done(init_calib_complete)
);
end
endgenerate
// ---- real DDR3 behavioral model (single component, DQ_WIDTH=16
// matches MEMORY_WIDTH=16 exactly, no splitting needed) ----
ddr3_model u_ddr3 (
.rst_n(ddr3_reset_n), .ck(ddr3_ck_p_sdram), .ck_n(ddr3_ck_n_sdram),
.cke(ddr3_cke_sdram[0]), .cs_n(ddr3_cs_n_sdram[0]),
.ras_n(ddr3_ras_n_sdram), .cas_n(ddr3_cas_n_sdram), .we_n(ddr3_we_n_sdram),
.dm_tdqs(ddr3_dm_sdram), .ba(ddr3_ba_sdram), .addr(ddr3_addr_sdram),
.dq(ddr3_dq_sdram), .dqs(ddr3_dqs_p_sdram), .dqs_n(ddr3_dqs_n_sdram),
.tdqs_n(), .odt(ddr3_odt_sdram[0])
);
// ---- real MIG controller (inner module, SIM_BYPASS_INIT_CAL
// overridden for a real but fast simulation calibration) ----
wire [27:0] app_addr;
wire [2:0] app_cmd;
wire app_en, app_rdy;
wire [63:0] app_wdf_data;
wire app_wdf_end;
wire [7:0] app_wdf_mask;
wire app_wdf_wren, app_wdf_rdy;
wire [63:0] app_rd_data;
wire app_rd_data_end, app_rd_data_valid;
wire ui_clk, ui_clk_sync_rst, init_calib_complete;
mig_7series_0_mig #(
.SIM_BYPASS_INIT_CAL("FAST")
) u_mig (
.ddr3_dq(ddr3_dq_fpga), .ddr3_dqs_n(ddr3_dqs_n_fpga), .ddr3_dqs_p(ddr3_dqs_p_fpga),
.ddr3_addr(ddr3_addr_fpga), .ddr3_ba(ddr3_ba_fpga),
.ddr3_ras_n(ddr3_ras_n_fpga), .ddr3_cas_n(ddr3_cas_n_fpga), .ddr3_we_n(ddr3_we_n_fpga),
.ddr3_reset_n(ddr3_reset_n),
.ddr3_ck_p(ddr3_ck_p_fpga), .ddr3_ck_n(ddr3_ck_n_fpga),
.ddr3_cke(ddr3_cke_fpga), .ddr3_cs_n(ddr3_cs_n_fpga),
.ddr3_dm(ddr3_dm_fpga), .ddr3_odt(ddr3_odt_fpga),
.sys_clk_i(sys_clk_i), .clk_ref_i(clk_ref_i),
.app_addr(app_addr), .app_cmd(app_cmd), .app_en(app_en),
.app_wdf_data(app_wdf_data), .app_wdf_end(app_wdf_end),
.app_wdf_mask(app_wdf_mask), .app_wdf_wren(app_wdf_wren),
.app_rd_data(app_rd_data), .app_rd_data_end(app_rd_data_end),
.app_rd_data_valid(app_rd_data_valid), .app_rdy(app_rdy), .app_wdf_rdy(app_wdf_rdy),
.app_sr_req(1'b0), .app_ref_req(1'b0), .app_zq_req(1'b0),
.app_sr_active(), .app_ref_ack(), .app_zq_ack(),
.ui_clk(ui_clk), .ui_clk_sync_rst(ui_clk_sync_rst),
.init_calib_complete(init_calib_complete),
.device_temp(),
.sys_rst(sys_rst)
);
// ---- adapter under test ----
reg req, wr;
reg [ADDR_WIDTH-1:0] addr;
reg [16*BURST_LEN-1:0] wdata;
reg [2*BURST_LEN-1:0] wmask;
wire [16*BURST_LEN-1:0] rdata;
wire ready, busy;
mig_native_adapter #(.BURST_LEN(BURST_LEN), .ADDR_WIDTH(ADDR_WIDTH)) u_adapter (
.clk(ui_clk), .rst(ui_clk_sync_rst),
.req(req), .wr(wr), .addr(addr), .wdata(wdata), .wmask(wmask),
.rdata(rdata), .ready(ready), .busy(busy),
.app_addr(app_addr), .app_cmd(app_cmd), .app_en(app_en), .app_rdy(app_rdy),
.app_wdf_data(app_wdf_data), .app_wdf_end(app_wdf_end), .app_wdf_mask(app_wdf_mask),
.app_wdf_wren(app_wdf_wren), .app_wdf_rdy(app_wdf_rdy),
.app_rd_data(app_rd_data), .app_rd_data_end(app_rd_data_end), .app_rd_data_valid(app_rd_data_valid)
);
task automatic do_txn(
input t_wr,
input [ADDR_WIDTH-1:0] t_addr,
input [16*BURST_LEN-1:0] t_wdata,
output [16*BURST_LEN-1:0] t_rdata
);
begin
@(posedge ui_clk);
while (busy) @(posedge ui_clk);
req = 1'b1; wr = t_wr; addr = t_addr; wdata = t_wdata; wmask = {(2*BURST_LEN){1'b0}};
@(posedge ui_clk);
req = 1'b0;
while (!ready) @(posedge ui_clk);
t_rdata = rdata;
end
endtask
integer errors, tests;
reg [16*BURST_LEN-1:0] got, wpat;
integer k, i;
task automatic check_addr(input [ADDR_WIDTH-1:0] a, input [15:0] pattern);
begin
for (k = 0; k < BURST_LEN; k = k + 1)
wpat[k*16 +: 16] = pattern + k[15:0];
do_txn(1'b1, a, wpat, got);
do_txn(1'b0, a, {(16*BURST_LEN){1'b0}}, got);
tests = tests + 1;
if (got !== wpat) begin
$display("FAIL addr=%0d: got=%h expected=%h", a, got, wpat);
errors = errors + 1;
end else begin
$display("PASS addr=%0d: bit-exact %h", a, got);
end
end
endtask
initial begin
errors = 0; tests = 0;
req = 0; wr = 0; addr = 0; wdata = 0; wmask = 0;
$display("=== waiting for real DDR3 init_calib_complete (FAST sim calibration) ===");
wait (init_calib_complete);
$display("=== calibration done at time %0t, starting real write/read-back test ===", $time);
repeat (10) @(posedge ui_clk);
check_addr(25'd0, 16'hA5A5);
check_addr(25'd8, 16'h1000);
check_addr(25'd16, 16'h2000);
check_addr(25'd1024,16'h3000);
for (i = 0; i < 8; i = i + 1)
check_addr((25'd2048 + i*8), 16'h4000 + i);
$display("=== %0d/%0d tests, %0d errors ===", tests-errors, tests, errors);
if (errors == 0) $display("ALL TESTS PASSED (tb_mig_native_adapter, real ddr3_model.sv)");
else $display("SOME TESTS FAILED");
$finish;
end
initial begin
#200000000.0; // 200us watchdog
if (!init_calib_complete) $display("FAIL: calibration never completed within watchdog");
else $display("(watchdog fired after calibration already completed -- not a failure by itself)");
$finish;
end
endmodule
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`timescale 1ns/1ps
// ============================================================
// Isolated correctness test for sdram_arbiter_n.v (NUM_REQ=3, the
// immediate real use case: 2 packed slots + 1 host raw-access
// requester). Each requester stub mirrors layer_prefetch_ctrl.v's
// own real, risky pattern that caused EXP-0066's real bug: a ONE-SHOT
// ctrl_req pulse issued the instant its own `active` first goes high,
// no retry -- this test exists specifically to re-confirm the
// combinational-first-grant fix generalizes correctly to N=3, not
// just N=2.
// ============================================================
module tb;
localparam BURST_LEN = 8;
localparam ROW_BITS = 13;
localparam COL_BITS = 10;
localparam BANK_BITS = 2;
localparam ADDR_WIDTH = BANK_BITS + ROW_BITS + COL_BITS;
localparam CLK_FREQ_MHZ = 64;
localparam CLK_PERIOD_NS = 1000.0/CLK_FREQ_MHZ;
localparam NUM_REQ = 3;
reg clk = 0;
always #(CLK_PERIOD_NS/2.0) clk = ~clk;
reg rst;
wire ctrl_req, ctrl_wr;
wire [ADDR_WIDTH-1:0] ctrl_addr;
wire [16*BURST_LEN-1:0] ctrl_wdata, ctrl_rdata;
wire [2*BURST_LEN-1:0] ctrl_wmask;
wire ctrl_ready, ctrl_busy;
wire cke, cs_n, ras_n, cas_n, we_n;
wire [BANK_BITS-1:0] ba;
wire [ROW_BITS-1:0] a;
wire [15:0] dq;
wire [1:0] dqm;
sdram_controller #(
.CLK_FREQ_MHZ(CLK_FREQ_MHZ), .BURST_LEN(BURST_LEN),
.ROW_BITS(ROW_BITS), .COL_BITS(COL_BITS), .BANK_BITS(BANK_BITS)
) u_ctrl (
.clk(clk), .rst(rst),
.req(ctrl_req), .wr(ctrl_wr), .addr(ctrl_addr), .wdata(ctrl_wdata), .wmask(ctrl_wmask),
.rdata(ctrl_rdata), .ready(ctrl_ready), .busy(ctrl_busy),
.sdram_cke(cke), .sdram_cs_n(cs_n), .sdram_ras_n(ras_n), .sdram_cas_n(cas_n), .sdram_we_n(we_n),
.sdram_ba(ba), .sdram_a(a), .sdram_dq(dq), .sdram_dqm(dqm)
);
sdram_model #(
.CLK_FREQ_MHZ(CLK_FREQ_MHZ), .ROW_BITS(ROW_BITS), .COL_BITS(COL_BITS), .BANK_BITS(BANK_BITS)
) u_mem (
.clk(clk), .cke(cke), .cs_n(cs_n), .ras_n(ras_n), .cas_n(cas_n), .we_n(we_n),
.ba(ba), .a(a), .dq(dq), .dqm(dqm)
);
reg [NUM_REQ-1:0] req_active, req_req, req_wr;
wire [NUM_REQ-1:0] req_grant, req_ready, req_busy;
reg [NUM_REQ*ADDR_WIDTH-1:0] req_addr;
reg [NUM_REQ*16*BURST_LEN-1:0] req_wdata;
reg [NUM_REQ*2*BURST_LEN-1:0] req_wmask;
wire [NUM_REQ*16*BURST_LEN-1:0] req_rdata;
sdram_arbiter_n #(
.NUM_REQ(NUM_REQ), .ADDR_WIDTH(ADDR_WIDTH), .BURST_LEN(BURST_LEN)
) u_arb (
.clk(clk), .rst(rst),
.req_active(req_active), .req_grant(req_grant),
.req_req(req_req), .req_wr(req_wr), .req_addr(req_addr),
.req_wdata(req_wdata), .req_wmask(req_wmask),
.req_rdata(req_rdata), .req_ready(req_ready), .req_busy(req_busy),
.ctrl_req(ctrl_req), .ctrl_wr(ctrl_wr), .ctrl_addr(ctrl_addr),
.ctrl_wdata(ctrl_wdata), .ctrl_wmask(ctrl_wmask),
.ctrl_rdata(ctrl_rdata), .ctrl_ready(ctrl_ready), .ctrl_busy(ctrl_busy)
);
integer errors, tests;
// one-shot-pulse requester task: mirrors layer_prefetch_ctrl.v's
// own real risk pattern -- raise active, issue req THE SAME cycle
// active first asserts (no waiting for grant confirmation first),
// no retry if lost.
task automatic one_shot_txn(
input integer slot, input t_wr, input [ADDR_WIDTH-1:0] t_addr,
input [16*BURST_LEN-1:0] t_wdata, output [16*BURST_LEN-1:0] t_rdata
);
begin
@(posedge clk);
req_active[slot] = 1'b1;
req_req[slot] = 1'b1;
req_wr[slot] = t_wr;
req_addr[slot*ADDR_WIDTH +: ADDR_WIDTH] = t_addr;
req_wdata[slot*16*BURST_LEN +: 16*BURST_LEN] = t_wdata;
req_wmask[slot*2*BURST_LEN +: 2*BURST_LEN] = {(2*BURST_LEN){1'b0}};
@(posedge clk);
req_req[slot] = 1'b0;
while (!req_ready[slot]) @(posedge clk);
t_rdata = req_rdata[slot*16*BURST_LEN +: 16*BURST_LEN];
req_active[slot] = 1'b0;
end
endtask
reg [16*BURST_LEN-1:0] got, wpat;
integer k;
task automatic check_slot(input integer slot, input [ADDR_WIDTH-1:0] a, input [15:0] pattern);
integer i;
begin
for (i = 0; i < BURST_LEN; i = i + 1)
wpat[i*16 +: 16] = pattern + i[15:0];
one_shot_txn(slot, 1'b1, a, wpat, got);
one_shot_txn(slot, 1'b0, a, {(16*BURST_LEN){1'b0}}, got);
tests = tests + 1;
if (got !== wpat) begin
$display("FAIL slot=%0d addr=%0d: got=%h expected=%h", slot, a, got, wpat);
errors = errors + 1;
end else begin
$display("PASS slot=%0d addr=%0d: bit-exact", slot, a);
end
end
endtask
integer i;
initial begin
errors = 0; tests = 0;
rst = 1; req_active = 0; req_req = 0; req_wr = 0; req_addr = 0; req_wdata = 0; req_wmask = 0;
repeat(5) @(posedge clk);
rst = 0;
@(posedge clk);
$display("=== TEST 1: sequential single-requester transactions, all 3 slots ===");
check_slot(0, 25'd0, 16'hA000);
check_slot(1, 25'd8, 16'hB000);
check_slot(2, 25'd16, 16'hC000);
$display("=== TEST 2: simultaneous multi-requester activation (the real EXP-0066 risk case) ===");
begin : test2
reg [16*BURST_LEN-1:0] g0, g1, g2, w0, w1, w2;
integer kk;
for (kk = 0; kk < BURST_LEN; kk = kk + 1) begin
w0[kk*16 +: 16] = 16'hD000 + kk[15:0];
w1[kk*16 +: 16] = 16'hE000 + kk[15:0];
w2[kk*16 +: 16] = 16'hF000 + kk[15:0];
end
// all three assert `active`+`req` on the SAME cycle --
// exactly the scenario a registered/late grant loses.
@(posedge clk);
req_active = 3'b111; req_req = 3'b111;
req_wr[0] = 1'b1; req_wr[1] = 1'b1; req_wr[2] = 1'b1;
req_addr[0*ADDR_WIDTH +: ADDR_WIDTH] = 25'd100;
req_addr[1*ADDR_WIDTH +: ADDR_WIDTH] = 25'd108;
req_addr[2*ADDR_WIDTH +: ADDR_WIDTH] = 25'd116;
req_wdata[0*16*BURST_LEN +: 16*BURST_LEN] = w0;
req_wdata[1*16*BURST_LEN +: 16*BURST_LEN] = w1;
req_wdata[2*16*BURST_LEN +: 16*BURST_LEN] = w2;
@(posedge clk);
req_req = 3'b000;
// slot 0 (lowest index) must win first; 1 and 2 must NOT
// silently lose their request -- wait for each in turn.
while (!req_ready[0]) @(posedge clk);
req_active[0] = 1'b0;
while (!req_ready[1]) @(posedge clk);
req_active[1] = 1'b0;
while (!req_ready[2]) @(posedge clk);
req_active[2] = 1'b0;
tests = tests + 1;
$display("PASS TEST2: all 3 simultaneous requests completed (none silently lost)");
// now read back all three and confirm bit-exact, real
// proof none of the writes were corrupted/misrouted.
check_slot(0, 25'd100, 16'hD000);
check_slot(1, 25'd108, 16'hE000);
check_slot(2, 25'd116, 16'hF000);
end
$display("=== %0d/%0d tests, %0d errors ===", tests-errors, tests, errors);
if (errors == 0) $display("ALL TESTS PASSED (tb_sdram_arbiter_n)");
$finish;
end
endmodule