// // Copyright 2011 Ettus Research LLC // // This program is free software: you can redistribute it and/or modify // it under the terms of the GNU General Public License as published by // the Free Software Foundation, either version 3 of the License, or // (at your option) any later version. // // This program is distributed in the hope that it will be useful, // but WITHOUT ANY WARRANTY; without even the implied warranty of // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the // GNU General Public License for more details. // // You should have received a copy of the GNU General Public License // along with this program. If not, see . // module simple_gemac_tx (input clk125, input reset, output GMII_GTX_CLK, output reg GMII_TX_EN, output reg GMII_TX_ER, output reg [7:0] GMII_TXD, output tx_clk, input [7:0] tx_data, input tx_valid, input tx_error, output tx_ack, input [7:0] ifg, input [47:0] mac_addr, input pause_req, input [15:0] pause_time, input pause_apply, output reg paused ); reg tx_en_pre, tx_er_pre; reg [7:0] txd_pre; assign GMII_GTX_CLK = clk125; assign tx_clk = clk125; reg [7:0] tx_state; reg [7:0] ifg_ctr; reg [15:0] frame_len_ctr; reg [7:0] pause_ctr, pause_dat; wire in_ifg = (ifg_ctr != 0); wire [31:0] crc_out; localparam TX_IDLE = 0; localparam TX_PREAMBLE = 1; localparam TX_SOF_DEL = TX_PREAMBLE + 7; localparam TX_FIRSTBYTE = TX_SOF_DEL + 1; localparam TX_IN_FRAME = TX_FIRSTBYTE + 1; localparam TX_IN_FRAME_2 = TX_IN_FRAME + 1; localparam TX_PAD = TX_IN_FRAME_2 + 1; localparam TX_CRC_0 = 16; localparam TX_CRC_1 = TX_CRC_0 + 1; localparam TX_CRC_2 = TX_CRC_0 + 2; localparam TX_CRC_3 = TX_CRC_0 + 3; localparam TX_ERROR = 32; localparam TX_PAUSE = 55; localparam TX_PAUSE_SOF = TX_PAUSE + 7; localparam TX_PAUSE_FIRST = TX_PAUSE_SOF + 1; localparam TX_PAUSE_END = TX_PAUSE_SOF + 18; localparam MIN_FRAME_LEN = 64 + 8 - 4; // Min frame length includes preamble but not CRC localparam MAX_FRAME_LEN = 8192; // How big are the jumbo frames we want to handle? always @(posedge tx_clk) if(reset |(tx_state == TX_IDLE)) frame_len_ctr <= 0; else frame_len_ctr <= frame_len_ctr + 1; reg send_pause; reg [15:0] pause_time_held; always @(posedge tx_clk) if(reset) send_pause <= 0; else if(pause_req) send_pause <= 1; else if(tx_state == TX_PAUSE) send_pause <= 0; always @(posedge tx_clk) if(pause_req) pause_time_held <= pause_time; always @(posedge tx_clk) if(reset) tx_state <= TX_IDLE; else case(tx_state) TX_IDLE : if(~in_ifg) if(send_pause) tx_state <= TX_PAUSE; else if(tx_valid & ~pause_apply) tx_state <= TX_PREAMBLE; TX_FIRSTBYTE : if(tx_error) tx_state <= TX_ERROR; // underrun else if(~tx_valid) tx_state <= TX_PAD; else tx_state <= TX_IN_FRAME; TX_IN_FRAME : if(tx_error) tx_state <= TX_ERROR; // underrun else if(~tx_valid) tx_state <= TX_PAD; else if(frame_len_ctr == MIN_FRAME_LEN - 1) tx_state <= TX_IN_FRAME_2; TX_IN_FRAME_2 : if(tx_error) tx_state <= TX_ERROR; // underrun else if(~tx_valid) tx_state <= TX_CRC_0; TX_PAD : if(frame_len_ctr == MIN_FRAME_LEN) tx_state <= TX_CRC_0; TX_CRC_3 : tx_state <= TX_IDLE; TX_ERROR : tx_state <= TX_IDLE; TX_PAUSE_END : tx_state <= TX_PAD; default : tx_state <= tx_state + 1; endcase // case (tx_state) always @(posedge tx_clk) if(reset) begin tx_en_pre <= 0; tx_er_pre <= 0; txd_pre <= 0; end else casex(tx_state) TX_IDLE : begin tx_en_pre <= 0; tx_er_pre <= 0; txd_pre <= 0; end TX_PREAMBLE, TX_PAUSE : begin txd_pre <= 8'h55; tx_en_pre <= 1; end TX_SOF_DEL, TX_PAUSE_SOF : txd_pre <= 8'hD5; TX_FIRSTBYTE, TX_IN_FRAME, TX_IN_FRAME_2 : txd_pre <= tx_valid ? tx_data : 0; TX_ERROR : begin tx_er_pre <= 1; txd_pre <= 0; end TX_CRC_3 : tx_en_pre <= 0; TX_PAD : txd_pre <= 0; TX_PAUSE_FIRST, 8'b01xx_xxxx : // In Pause Frame txd_pre <= pause_dat; endcase // case (tx_state) localparam SGE_FLOW_CTRL_ADDR = 48'h01_80_C2_00_00_01; always @(posedge tx_clk) case(tx_state) TX_PAUSE_SOF : pause_dat <= SGE_FLOW_CTRL_ADDR[47:40]; // Note everything must be 1 cycle early TX_PAUSE_SOF + 1: pause_dat <= SGE_FLOW_CTRL_ADDR[39:32]; TX_PAUSE_SOF + 2: pause_dat <= SGE_FLOW_CTRL_ADDR[31:24]; TX_PAUSE_SOF + 3: pause_dat <= SGE_FLOW_CTRL_ADDR[23:16]; TX_PAUSE_SOF + 4: pause_dat <= SGE_FLOW_CTRL_ADDR[15:8]; TX_PAUSE_SOF + 5: pause_dat <= SGE_FLOW_CTRL_ADDR[7:0]; TX_PAUSE_SOF + 6: pause_dat <= mac_addr[47:40]; TX_PAUSE_SOF + 7: pause_dat <= mac_addr[39:32]; TX_PAUSE_SOF + 8: pause_dat <= mac_addr[31:24]; TX_PAUSE_SOF + 9: pause_dat <= mac_addr[23:16]; TX_PAUSE_SOF + 10: pause_dat <= mac_addr[15:8]; TX_PAUSE_SOF + 11: pause_dat <= mac_addr[7:0]; TX_PAUSE_SOF + 12: pause_dat <= 8'h88; // Type = 8808 = MAC ctrl frame TX_PAUSE_SOF + 13: pause_dat <= 8'h08; TX_PAUSE_SOF + 14: pause_dat <= 8'h00; // Opcode = 0001 = PAUSE TX_PAUSE_SOF + 15: pause_dat <= 8'h01; TX_PAUSE_SOF + 16: pause_dat <= pause_time_held[15:8]; TX_PAUSE_SOF + 17: pause_dat <= pause_time_held[7:0]; endcase // case (tx_state) wire start_ifg = (tx_state == TX_CRC_3); always @(posedge tx_clk) if(reset) ifg_ctr <= 100; else if(start_ifg) ifg_ctr <= ifg; else if(ifg_ctr != 0) ifg_ctr <= ifg_ctr - 1; wire clear_crc = (tx_state == TX_IDLE); wire calc_crc = (tx_state==TX_IN_FRAME) | (tx_state==TX_IN_FRAME_2) | (tx_state==TX_PAD) | (tx_state[6]); crc crc(.clk(tx_clk), .reset(reset), .clear(clear_crc), .data(txd_pre), .calc(calc_crc), .crc_out(crc_out)); assign tx_ack = (tx_state == TX_FIRSTBYTE); always @(posedge tx_clk) begin GMII_TX_EN <= tx_en_pre; GMII_TX_ER <= tx_er_pre; case(tx_state) TX_CRC_0 : GMII_TXD <= crc_out[31:24]; TX_CRC_1 : GMII_TXD <= crc_out[23:16]; TX_CRC_2 : GMII_TXD <= crc_out[15:8]; TX_CRC_3 : GMII_TXD <= crc_out[7:0]; default : GMII_TXD <= txd_pre; endcase // case (tx_state) end // report that we are paused only when we get back to IDLE always @(posedge tx_clk) if(reset) paused <= 0; else if(~pause_apply) paused <= 0; else if(tx_state == TX_IDLE) paused <= 1; endmodule // simple_gemac_tx // Testing code /* reg [7:0] crc_ctr; reg calc_crc_d1; always @(posedge tx_clk) calc_crc_d1 <= calc_crc; always @(posedge tx_clk) if(reset) crc_ctr <= 0; else if(calc_crc) crc_ctr <= crc_ctr+1; else if(calc_crc_d1) $display("CRC COUNT = %d",crc_ctr); else crc_ctr <= 0; */