Files
vortex/hw/rtl/cache/VX_snp_forwarder.v
2020-12-08 02:58:08 -08:00

220 lines
8.1 KiB
Verilog

`include "VX_cache_config.vh"
module VX_snp_forwarder #(
parameter CACHE_ID = 0,
parameter SRC_ADDR_WIDTH = 1,
parameter DST_ADDR_WIDTH = 1,
parameter NUM_REQS = 1,
parameter SREQ_SIZE = 1,
parameter TAG_IN_WIDTH = 1,
parameter TAG_OUT_WIDTH = `LOG2UP(SREQ_SIZE)
) (
input wire clk,
input wire reset,
// Snoop request
input wire snp_req_valid,
input wire [SRC_ADDR_WIDTH-1:0] snp_req_addr,
input wire snp_req_inv,
input wire [TAG_IN_WIDTH-1:0] snp_req_tag,
output wire snp_req_ready,
// Snoop response
output wire snp_rsp_valid,
output wire [SRC_ADDR_WIDTH-1:0] snp_rsp_addr,
output wire snp_rsp_inv,
output wire [TAG_IN_WIDTH-1:0] snp_rsp_tag,
input wire snp_rsp_ready,
// Snoop Forwarding out
output wire [NUM_REQS-1:0] snp_fwdout_valid,
output wire [NUM_REQS-1:0][DST_ADDR_WIDTH-1:0] snp_fwdout_addr,
output wire [NUM_REQS-1:0] snp_fwdout_inv,
output wire [NUM_REQS-1:0][TAG_OUT_WIDTH-1:0] snp_fwdout_tag,
input wire [NUM_REQS-1:0] snp_fwdout_ready,
// Snoop forwarding in
input wire [NUM_REQS-1:0] snp_fwdin_valid,
input wire [NUM_REQS-1:0][TAG_OUT_WIDTH-1:0] snp_fwdin_tag,
output wire [NUM_REQS-1:0] snp_fwdin_ready
);
localparam ADDR_DIFF = DST_ADDR_WIDTH - SRC_ADDR_WIDTH;
localparam NUM_REQUESTS_QUAL = NUM_REQS * (1 << ADDR_DIFF);
localparam REQ_QUAL_BITS = `LOG2UP(NUM_REQUESTS_QUAL);
if (NUM_REQS > 1) begin
reg [REQ_QUAL_BITS:0] pending_cntrs [SREQ_SIZE-1:0];
wire [TAG_OUT_WIDTH-1:0] sfq_write_addr, sfq_read_addr;
wire sfq_full;
wire [TAG_OUT_WIDTH-1:0] fwdin_tag;
wire fwdin_valid;
wire fwdin_ready = snp_rsp_ready || (1 != pending_cntrs[sfq_read_addr]);
wire fwdin_fire = fwdin_valid && fwdin_ready;
assign snp_rsp_valid = fwdin_valid && (1 == pending_cntrs[sfq_read_addr]);
assign sfq_read_addr = fwdin_tag;
wire sfq_acquire = snp_req_valid && snp_req_ready;
wire sfq_release = snp_rsp_valid && snp_rsp_ready;
VX_cam_buffer #(
.DATAW (SRC_ADDR_WIDTH + 1 + TAG_IN_WIDTH),
.SIZE (SREQ_SIZE)
) req_metadata_buf (
.clk (clk),
.reset (reset),
.write_addr (sfq_write_addr),
.acquire_slot (sfq_acquire),
.read_addr (sfq_read_addr),
.write_data ({snp_req_addr, snp_req_inv, snp_req_tag}),
.read_data ({snp_rsp_addr, snp_rsp_inv, snp_rsp_tag}),
.release_addr (sfq_read_addr),
.release_slot (sfq_release),
.full (sfq_full)
);
wire fwdout_valid;
wire [TAG_OUT_WIDTH-1:0] fwdout_tag;
wire [DST_ADDR_WIDTH-1:0] fwdout_addr;
wire fwdout_inv;
wire fwdout_ready;
wire dispatch_hold;
if (ADDR_DIFF != 0) begin
reg [TAG_OUT_WIDTH-1:0] fwdout_tag_r;
reg [DST_ADDR_WIDTH-1:0] fwdout_addr_r;
reg fwdout_inv_r;
reg dispatch_hold_r;
always @(posedge clk) begin
if (reset) begin
dispatch_hold_r <= 0;
end else begin
if (snp_req_valid && snp_req_ready) begin
dispatch_hold_r <= 1;
end
if (dispatch_hold_r
&& fwdout_ready
&& (fwdout_addr[ADDR_DIFF-1:0] == ((1 << ADDR_DIFF)-1))) begin
dispatch_hold_r <= 0;
end
end
if (fwdout_valid && fwdout_ready) begin
fwdout_addr_r <= fwdout_addr + DST_ADDR_WIDTH'(1'b1);
end
if (snp_req_valid && snp_req_ready) begin
fwdout_inv_r <= snp_req_inv;
fwdout_tag_r <= sfq_write_addr;
end
end
assign fwdout_valid = dispatch_hold_r || (snp_req_valid && !sfq_full);
assign fwdout_tag = dispatch_hold_r ? fwdout_tag_r : sfq_write_addr;
assign fwdout_addr = dispatch_hold_r ? fwdout_addr_r : {snp_req_addr, ADDR_DIFF'(0)};
assign fwdout_inv = dispatch_hold_r ? fwdout_inv_r : snp_req_inv;
assign dispatch_hold= dispatch_hold_r;
end else begin
assign fwdout_valid = snp_req_valid && !sfq_full;
assign fwdout_tag = sfq_write_addr;
assign fwdout_addr = snp_req_addr;
assign fwdout_inv = snp_req_inv;
assign dispatch_hold= 1'b0;
end
always @(posedge clk) begin
if (sfq_acquire) begin
pending_cntrs[sfq_write_addr] <= NUM_REQUESTS_QUAL;
end
if (fwdin_fire) begin
pending_cntrs[sfq_read_addr] <= pending_cntrs[sfq_read_addr] - 1;
end
end
reg [NUM_REQS-1:0] snp_fwdout_ready_other;
for (genvar i = 0; i < NUM_REQS; i++) begin
assign snp_fwdout_valid[i] = fwdout_valid && snp_fwdout_ready_other[i];
assign snp_fwdout_addr[i] = fwdout_addr;
assign snp_fwdout_inv[i] = fwdout_inv;
assign snp_fwdout_tag[i] = fwdout_tag;
end
always @(*) begin
snp_fwdout_ready_other = {NUM_REQS{1'b1}};
for (integer i = 0; i < NUM_REQS; i++) begin
for (integer j = 0; j < NUM_REQS; j++) begin
if (i != j)
snp_fwdout_ready_other[i] &= snp_fwdout_ready[j];
end
end
end
assign fwdout_ready = (& snp_fwdout_ready);
assign snp_req_ready = fwdout_ready && !sfq_full && !dispatch_hold;
VX_stream_arbiter #(
.NUM_REQS (NUM_REQS),
.DATAW (TAG_OUT_WIDTH),
.IN_BUFFER (NUM_REQS >= 4),
.OUT_BUFFER (NUM_REQS >= 4)
) snp_fwdin_arb (
.clk (clk),
.reset (reset),
.valid_in (snp_fwdin_valid),
.data_in (snp_fwdin_tag),
.ready_in (snp_fwdin_ready),
.valid_out (fwdin_valid),
.data_out (fwdin_tag),
.ready_out (fwdin_ready)
);
`ifdef DBG_PRINT_CACHE_SNP
always @(posedge clk) begin
if (fwdin_valid && fwdin_ready) begin
$display("%t: cache%0d snp-fwd-in: tag=%0h", $time, CACHE_ID, fwdin_tag);
end
end
`endif
end else begin
`UNUSED_VAR (clk)
`UNUSED_VAR (reset)
assign snp_fwdout_valid = snp_req_valid;
assign snp_fwdout_addr = snp_req_addr;
assign snp_fwdout_inv = snp_req_inv;
assign snp_fwdout_tag = snp_req_tag;
assign snp_req_ready = snp_fwdout_ready;
assign snp_rsp_valid = snp_fwdin_valid;
assign snp_rsp_addr = snp_req_addr;
assign snp_rsp_inv = snp_req_inv;
assign snp_rsp_tag = snp_fwdin_tag;
assign snp_fwdin_ready = snp_rsp_ready;
end
`ifdef DBG_PRINT_CACHE_SNP
always @(posedge clk) begin
if (snp_req_valid && snp_req_ready) begin
$display("%t: cache%0d snp-fwd-req: addr=%0h, invalidate=%0d, tag=%0h", $time, CACHE_ID, `TO_FULL_ADDR(snp_req_addr), snp_req_inv, snp_req_tag);
end
if (snp_fwdout_valid[0] && snp_fwdout_ready[0]) begin
$display("%t: cache%0d snp-fwd-out: addr=%0h, invalidate=%0d, tag=%0h", $time, CACHE_ID, `TO_FULL_ADDR(snp_fwdout_addr[0]), snp_fwdout_inv[0], snp_fwdout_tag[0]);
end
if (snp_rsp_valid && snp_rsp_ready) begin
$display("%t: cache%0d snp-fwd-rsp: addr=%0h, invalidate=%0d, tag=%0h", $time, CACHE_ID, snp_rsp_addr, snp_rsp_inv, snp_rsp_tag);
end
end
`endif
endmodule