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Remove flush logic from arbiter, moved to units

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This commit is contained in:
Florian Zaruba 2017-05-29 18:36:28 +02:00
parent b2ad6f058e
commit 778d63355b
2 changed files with 21 additions and 53 deletions
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73
src/dcache_arbiter.sv
View file

@ -25,7 +25,6 @@ module dcache_arbiter #(
(
input logic clk_i, // Clock
input logic rst_ni, // Asynchronous reset active low
input logic flush_i,
// slave port
output logic [11:0] address_index_o,
output logic [43:0] address_tag_o,
@ -53,8 +52,6 @@ module dcache_arbiter #(
);
// one-hot encoded
localparam DATA_WIDTH = NR_PORTS;
// registers
enum logic {IDLE, WAIT_FLUSH} CS, NS;
// remember the request port in case of a multi-cycle transaction
logic [DATA_WIDTH-1:0] request_port_n, request_port_q;
// local ports
@ -68,12 +65,6 @@ module dcache_arbiter #(
// FIFO output port
logic [DATA_WIDTH-1:0] out_data;
logic pop;
logic flush_ready;
// essentially wait for the queue to be empty
// or we just got a grant -> this means we issued a memory request in this cycle
// although we are ready if we only got a single element in the queue and an rvalid
// which means we are getting this element back in this cycle
assign flush_ready = (empty & ~(|data_gnt_i)) | (single_element & data_rvalid_i);
fifo #(
.dtype ( logic [DATA_WIDTH-1:0] ),
@ -96,51 +87,36 @@ module dcache_arbiter #(
always_comb begin : read_req_write
automatic logic [DATA_WIDTH-1:0] request_index = request_port_q;
data_req_o = 1'b0;
in_data = '{default: 0};
push = 1'b0;
request_port_n = request_port_q;
NS = CS;
for (int i = 0; i < NR_PORTS; i++)
data_gnt_o[i] = 1'b0;
case (CS)
// ----------------------------
// Single-cycle memory requests
// ----------------------------
IDLE: begin
// only go for a new request if we can wait for the valid e.g.: we have enough space in the buffer
if (~full) begin
for (int unsigned i = 0; i < NR_PORTS; i++) begin
if (data_req_i[i] == 1'b1) begin
data_req_o = data_req_i[i];
// save the request port for future states
request_port_n = i;
request_index = i;
// wait for the grant
if (data_gnt_i) begin
// set the slave on which we are waiting
in_data = 1'b1 << i[DATA_WIDTH-1:0];
push = 1'b1;
end
break; // break here as this is a priority select
end
// ----------------------------
// Single-cycle memory requests
// ----------------------------
// only go for a new request if we can wait for the valid e.g.: we have enough space in the buffer
if (~full) begin
for (int unsigned i = 0; i < NR_PORTS; i++) begin
if (data_req_i[i] == 1'b1) begin
data_req_o = data_req_i[i];
// save the request port for future states
request_port_n = i;
request_index = i;
// wait for the grant
if (data_gnt_i) begin
// set the slave on which we are waiting
in_data = 1'b1 << i[DATA_WIDTH-1:0];
push = 1'b1;
end
break; // break here as this is a priority select
end
end
// ----------------------------
// Flush logic
// ----------------------------
// here we are waiting for the FIFO to drain until we are ready to accept new requests
WAIT_FLUSH: begin
// if the flush has finished go to IDLE
if (flush_ready)
NS = IDLE;
end
default : /* default */;
endcase
end
// pass through all signals from the correct slave port
address_index_o = address_index_i[request_index];
data_wdata_o = data_wdata_i[request_index];
@ -151,11 +127,6 @@ module dcache_arbiter #(
address_tag_o = address_tag_i[request_port_q];
kill_req_o = kill_req_i[request_port_q];
tag_valid_o = tag_valid_i[request_port_q];
// if we got a flush and we are not ready for the flush wait and for it and don't accept any incoming data
// e.g.: jump to the flush wait state
if (flush_i && !flush_ready)
NS = WAIT_FLUSH;
end
// ------------
@ -183,11 +154,9 @@ module dcache_arbiter #(
// sequential process
always_ff @(posedge clk_i or negedge rst_ni) begin
if(~rst_ni) begin
CS <= IDLE;
if (~rst_ni) begin
request_port_q <= 1'b0;
end else begin
CS <= NS;
request_port_q <= request_port_n;
end
end

1
tb/dcache_arbiter_tb.sv
View file

@ -40,7 +40,6 @@ module dcache_arbiter_tb;
dcache_arbiter dut (
.clk_i ( clk ),
.rst_ni ( rst_ni ),
.flush_i ( 1'b0 ),
.address_index_o ( slave.address_index ),
.address_tag_o ( slave.address_tag ),