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Implement ARP cache clear

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This commit is contained in:
Alex Forencich 2019-06-14 00:01:13 -07:00
parent b41ab00381
commit ce13522085
1 changed files with 19 additions and 4 deletions
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23
rtl/arp_cache.v
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@ -71,6 +71,7 @@ reg [31:0] query_ip_reg = 0;
reg write_ip_valid_reg = 0, write_ip_valid_next;
reg [31:0] write_ip_reg = 0;
reg [47:0] write_mac_reg = 0;
reg clear_cache_reg = 0, clear_cache_next;
reg [CACHE_ADDR_WIDTH-1:0] wr_ptr_reg = {CACHE_ADDR_WIDTH{1'b0}}, wr_ptr_next;
reg [CACHE_ADDR_WIDTH-1:0] rd_ptr_reg = {CACHE_ADDR_WIDTH{1'b0}}, rd_ptr_next;
@ -148,9 +149,11 @@ always @* begin
wr_ptr_next = wr_ptr_reg;
rd_ptr_next = rd_ptr_reg;
clear_cache_next = clear_cache_reg | clear_cache;
query_ip_valid_next = query_ip_valid_reg;
query_request_ready_next = ~query_ip_valid_reg || ~query_request_valid || query_response_ready;
query_request_ready_next = (~query_ip_valid_reg || ~query_request_valid || query_response_ready) && !clear_cache_next;
query_response_valid_next = query_response_valid_reg & ~query_response_ready;
query_response_error_next = query_response_error_reg;
@ -173,7 +176,7 @@ always @* begin
write_ip_valid_next = write_ip_valid_reg;
write_request_ready_next = 1'b1;
write_request_ready_next = !clear_cache_next;
if (write_ip_valid_reg) begin
write_ip_valid_next = 0;
@ -185,6 +188,15 @@ always @* begin
write_ip_valid_next = 1;
wr_ptr_next = write_request_hash[CACHE_ADDR_WIDTH-1:0];
end
if (clear_cache) begin
clear_cache_next = 1'b1;
wr_ptr_next = 0;
end else if (clear_cache_reg) begin
wr_ptr_next = wr_ptr_reg + 1;
clear_cache_next = wr_ptr_next != 0;
mem_write = 1;
end
end
always @(posedge clk) begin
@ -194,12 +206,16 @@ always @(posedge clk) begin
query_response_valid_reg <= 1'b0;
write_ip_valid_reg <= 1'b0;
write_request_ready_reg <= 1'b0;
clear_cache_reg <= 1'b1;
wr_ptr_reg <= 0;
end else begin
query_ip_valid_reg <= query_ip_valid_next;
query_request_ready_reg <= query_request_ready_next;
query_response_valid_reg <= query_response_valid_next;
write_ip_valid_reg <= write_ip_valid_next;
write_request_ready_reg <= write_request_ready_next;
clear_cache_reg <= clear_cache_next;
wr_ptr_reg <= wr_ptr_next;
end
query_response_error_reg <= query_response_error_next;
@ -213,13 +229,12 @@ always @(posedge clk) begin
write_mac_reg <= write_request_mac;
end
wr_ptr_reg <= wr_ptr_next;
rd_ptr_reg <= rd_ptr_next;
query_response_mac_reg <= mac_addr_mem[rd_ptr_reg];
if (mem_write) begin
valid_mem[wr_ptr_reg] <= 1'b1;
valid_mem[wr_ptr_reg] <= !clear_cache_reg;
ip_addr_mem[wr_ptr_reg] <= write_ip_reg;
mac_addr_mem[wr_ptr_reg] <= write_mac_reg;
end