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[/] [pci/] [tags/] [rel_5/] [rtl/] [verilog/] [pci_wbw_wbr_fifos.v] - Rev 154
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////////////////////////////////////////////////////////////////////// //// //// //// File name "wbw_wbr_fifos.v" //// //// //// //// This file is part of the "PCI bridge" project //// //// http://www.opencores.org/cores/pci/ //// //// //// //// Author(s): //// //// - Miha Dolenc (mihad@opencores.org) //// //// //// //// All additional information is avaliable in the README //// //// file. //// //// //// //// //// ////////////////////////////////////////////////////////////////////// //// //// //// Copyright (C) 2001 Miha Dolenc, mihad@opencores.org //// //// //// //// This source file may be used and distributed without //// //// restriction provided that this copyright statement is not //// //// removed from the file and that any derivative work contains //// //// the original copyright notice and the associated disclaimer. //// //// //// //// This source file is free software; you can redistribute it //// //// and/or modify it under the terms of the GNU Lesser General //// //// Public License as published by the Free Software Foundation; //// //// either version 2.1 of the License, or (at your option) any //// //// later version. //// //// //// //// This source 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 Lesser General Public License for more //// //// details. //// //// //// //// You should have received a copy of the GNU Lesser General //// //// Public License along with this source; if not, download it //// //// from http://www.opencores.org/lgpl.shtml //// //// //// ////////////////////////////////////////////////////////////////////// // // CVS Revision History // // $Log: not supported by cvs2svn $ // Revision 1.1 2003/01/27 16:49:31 mihad // Changed module and file names. Updated scripts accordingly. FIFO synchronizations changed. // // Revision 1.9 2002/10/18 03:36:37 tadejm // Changed wrong signal name scanb_sen into scanb_en. // // Revision 1.8 2002/10/17 22:49:22 tadejm // Changed BIST signals for RAMs. // // Revision 1.7 2002/10/11 10:09:01 mihad // Added additional testcase and changed rst name in BIST to trst // // Revision 1.6 2002/10/08 17:17:06 mihad // Added BIST signals for RAMs. // // Revision 1.5 2002/09/30 16:03:04 mihad // Added meta flop module for easier meta stable FF identification during synthesis // // Revision 1.4 2002/09/25 15:53:52 mihad // Removed all logic from asynchronous reset network // // Revision 1.3 2002/02/01 15:25:14 mihad // Repaired a few bugs, updated specification, added test bench files and design document // // Revision 1.2 2001/10/05 08:20:12 mihad // Updated all files with inclusion of timescale file for simulation purposes. // // Revision 1.1.1.1 2001/10/02 15:33:47 mihad // New project directory structure // // `include "pci_constants.v" // synopsys translate_off `include "timescale.v" // synopsys translate_on module pci_wbw_wbr_fifos ( wb_clock_in, pci_clock_in, reset_in, wbw_wenable_in, wbw_addr_data_in, wbw_cbe_in, wbw_control_in, wbw_renable_in, wbw_addr_data_out, wbw_cbe_out, wbw_control_out, // wbw_flush_in, write fifo flush not used wbw_almost_full_out, wbw_full_out, wbw_empty_out, wbw_transaction_ready_out, wbr_wenable_in, wbr_data_in, wbr_be_in, wbr_control_in, wbr_renable_in, wbr_data_out, wbr_be_out, wbr_control_out, wbr_flush_in, wbr_empty_out `ifdef PCI_BIST , // debug chain signals scanb_rst, // bist scan reset scanb_clk, // bist scan clock scanb_si, // bist scan serial in scanb_so, // bist scan serial out scanb_en // bist scan shift enable `endif ) ; /*----------------------------------------------------------------------------------------------------------- System inputs: wb_clock_in - WISHBONE bus clock pci_clock_in - PCI bus clock reset_in - reset from control logic -------------------------------------------------------------------------------------------------------------*/ input wb_clock_in, pci_clock_in, reset_in ; /*----------------------------------------------------------------------------------------------------------- WISHBONE WRITE FIFO interface signals prefixed with wbw_ - FIFO is used for posted writes initiated by WISHBONE master, traveling through FIFO and are completed on PCI by PCI master interface write enable signal: wbw_wenable_in = write enable input for WBW_FIFO - driven by WISHBONE slave interface data input signals: wbw_addr_data_in = data input - data from WISHBONE bus - first entry of transaction is address others are data entries wbw_cbe_in = bus command/byte enable(~SEL[3:0]) input - first entry of transaction is bus command, other are byte enables wbw_control_in = control input - encoded control bus input read enable signal: wbw_renable_in = read enable input driven by PCI master interface data output signals: wbw_addr_data_out = data output - data from WISHBONE bus - first entry of transaction is address, others are data entries wbw_cbe_out = bus command/byte enable output - first entry of transaction is bus command, others are byte enables wbw_control_out = control input - encoded control bus input status signals - monitored by various resources in the core wbw_flush_in = flush signal input for WBW_FIFO - when asserted, fifo is flushed(emptied) wbw_almost_full_out = almost full output from WBW_FIFO wbw_full_out = full output from WBW_FIFO wbw_empty_out = empty output from WBW_FIFO wbw_transaction_ready_out = output indicating that one complete transaction is waiting in WBW_FIFO -----------------------------------------------------------------------------------------------------------*/ // input control and data input wbw_wenable_in ; input [31:0] wbw_addr_data_in ; input [3:0] wbw_cbe_in ; input [3:0] wbw_control_in ; // output control and data input wbw_renable_in ; output [31:0] wbw_addr_data_out ; output [3:0] wbw_cbe_out ; output [3:0] wbw_control_out ; // flush input // input wbw_flush_in ; // not used // status outputs output wbw_almost_full_out ; output wbw_full_out ; output wbw_empty_out ; output wbw_transaction_ready_out ; /*----------------------------------------------------------------------------------------------------------- WISHBONE READ FIFO interface signals prefixed with wbr_ - FIFO is used for holding delayed read completions initiated by master on WISHBONE bus and completed on PCI bus, write enable signal: wbr_wenable_in = write enable input for WBR_FIFO - driven by PCI master interface data input signals: wbr_data_in = data input - data from PCI bus - there is no address entry here, since address is stored in separate register wbr_be_in = byte enable(~BE#[3:0]) input - byte enables - same through one transaction wbr_control_in = control input - encoded control bus input read enable signal: wbr_renable_in = read enable input driven by WISHBONE slave interface data output signals: wbr_data_out = data output - data from PCI bus wbr_be_out = byte enable output(~#BE) wbr_control_out = control output - encoded control bus output status signals - monitored by various resources in the core wbr_flush_in = flush signal input for WBR_FIFO - when asserted, fifo is flushed(emptied) wbr full_out = full output from WBR_FIFO wbr_empty_out = empty output from WBR_FIFO -----------------------------------------------------------------------------------------------------------*/ // input control and data input wbr_wenable_in ; input [31:0] wbr_data_in ; input [3:0] wbr_be_in ; input [3:0] wbr_control_in ; // output control and data input wbr_renable_in ; output [31:0] wbr_data_out ; output [3:0] wbr_be_out ; output [3:0] wbr_control_out ; // flush input input wbr_flush_in ; output wbr_empty_out ; `ifdef PCI_BIST /*----------------------------------------------------- BIST debug chain port signals -----------------------------------------------------*/ input scanb_rst; // bist scan reset input scanb_clk; // bist scan clock input scanb_si; // bist scan serial in output scanb_so; // bist scan serial out input scanb_en; // bist scan shift enable `endif /*----------------------------------------------------------------------------------------------------------- FIFO depth parameters: WBW_DEPTH = defines WBW_FIFO depth WBR_DEPTH = defines WBR_FIFO depth WBW_ADDR_LENGTH = defines WBW_FIFO's location address length = log2(WBW_DEPTH) WBR_ADDR_LENGTH = defines WBR_FIFO's location address length = log2(WBR_DEPTH) -----------------------------------------------------------------------------------------------------------*/ parameter WBW_DEPTH = `WBW_DEPTH ; parameter WBW_ADDR_LENGTH = `WBW_ADDR_LENGTH ; parameter WBR_DEPTH = `WBR_DEPTH ; parameter WBR_ADDR_LENGTH = `WBR_ADDR_LENGTH ; /*----------------------------------------------------------------------------------------------------------- wbw_wallow = WBW_FIFO write allow wire - writes to FIFO are allowed when FIFO isn't full and write enable is 1 wbw_rallow = WBW_FIFO read allow wire - reads from FIFO are allowed when FIFO isn't empty and read enable is 1 -----------------------------------------------------------------------------------------------------------*/ wire wbw_wallow ; wire wbw_rallow ; /*----------------------------------------------------------------------------------------------------------- wbr_wallow = WBR_FIFO write allow wire - writes to FIFO are allowed when FIFO isn't full and write enable is 1 wbr_rallow = WBR_FIFO read allow wire - reads from FIFO are allowed when FIFO isn't empty and read enable is 1 -----------------------------------------------------------------------------------------------------------*/ wire wbr_wallow ; wire wbr_rallow ; /*----------------------------------------------------------------------------------------------------------- wires for address port conections from WBW_FIFO control logic to RAM blocks used for WBW_FIFO -----------------------------------------------------------------------------------------------------------*/ wire [(WBW_ADDR_LENGTH - 1):0] wbw_raddr ; wire [(WBW_ADDR_LENGTH - 1):0] wbw_waddr ; /*----------------------------------------------------------------------------------------------------------- wires for address port conections from WBR_FIFO control logic to RAM blocks used for WBR_FIFO -----------------------------------------------------------------------------------------------------------*/ wire [(WBR_ADDR_LENGTH - 1):0] wbr_raddr ; wire [(WBR_ADDR_LENGTH - 1):0] wbr_waddr ; /*----------------------------------------------------------------------------------------------------------- WBW_FIFO transaction counters: used to count incoming transactions and outgoing transactions. When number of input transactions is equal to number of output transactions, it means that there isn't any complete transaction currently present in the FIFO. -----------------------------------------------------------------------------------------------------------*/ reg [(WBW_ADDR_LENGTH - 2):0] wbw_inTransactionCount ; reg [(WBW_ADDR_LENGTH - 2):0] wbw_outTransactionCount ; /*----------------------------------------------------------------------------------------------------------- wires monitoring control bus. When control bus on a write transaction has a value of `LAST, it means that complete transaction is in the FIFO. When control bus on a read transaction has a value of `LAST, it means that there was one complete transaction taken out of FIFO. -----------------------------------------------------------------------------------------------------------*/ wire wbw_last_in = wbw_control_in[`LAST_CTRL_BIT] ; wire wbw_last_out = wbw_control_out[`LAST_CTRL_BIT] ; wire wbw_empty ; wire wbr_empty ; assign wbw_empty_out = wbw_empty ; assign wbr_empty_out = wbr_empty ; // clear wires for fifos wire wbw_clear = reset_in /*|| wbw_flush_in*/ ; // WBW_FIFO clear flush not used wire wbr_clear = reset_in /*|| wbr_flush_in*/ ; // WBR_FIFO clear - flush changed from asynchronous to synchronous /*----------------------------------------------------------------------------------------------------------- Definitions of wires for connecting RAM instances -----------------------------------------------------------------------------------------------------------*/ wire [39:0] dpram_portA_output ; wire [39:0] dpram_portB_output ; wire [39:0] dpram_portA_input = {wbw_control_in, wbw_cbe_in, wbw_addr_data_in} ; wire [39:0] dpram_portB_input = {wbr_control_in, wbr_be_in, wbr_data_in} ; /*----------------------------------------------------------------------------------------------------------- Fifo output assignments - each ram port provides data for different fifo -----------------------------------------------------------------------------------------------------------*/ assign wbw_control_out = dpram_portB_output[39:36] ; assign wbr_control_out = dpram_portA_output[39:36] ; assign wbw_cbe_out = dpram_portB_output[35:32] ; assign wbr_be_out = dpram_portA_output[35:32] ; assign wbw_addr_data_out = dpram_portB_output[31:0] ; assign wbr_data_out = dpram_portA_output[31:0] ; `ifdef WB_RAM_DONT_SHARE /*----------------------------------------------------------------------------------------------------------- Piece of code in this ifdef section is used in applications which can provide enough RAM instances to accomodate four fifos - each occupying its own instance of ram. Ports are connected in such a way, that instances of RAMs can be changed from two port to dual port ( async read/write port ). In that case, write port is always port a and read port is port b. -----------------------------------------------------------------------------------------------------------*/ /*----------------------------------------------------------------------------------------------------------- Pad redundant address lines with zeros. This may seem stupid, but it comes in perfect for FPGA impl. -----------------------------------------------------------------------------------------------------------*/ /* wire [(`WBW_FIFO_RAM_ADDR_LENGTH - WBW_ADDR_LENGTH - 1):0] wbw_addr_prefix = {( `WBW_FIFO_RAM_ADDR_LENGTH - WBW_ADDR_LENGTH){1'b0}} ; wire [(`WBR_FIFO_RAM_ADDR_LENGTH - WBR_ADDR_LENGTH - 1):0] wbr_addr_prefix = {( `WBR_FIFO_RAM_ADDR_LENGTH - WBR_ADDR_LENGTH){1'b0}} ; */ // compose complete port addresses wire [(`WB_FIFO_RAM_ADDR_LENGTH-1):0] wbw_whole_waddr = wbw_waddr ; wire [(`WB_FIFO_RAM_ADDR_LENGTH-1):0] wbw_whole_raddr = wbw_raddr ; wire [(`WB_FIFO_RAM_ADDR_LENGTH-1):0] wbr_whole_waddr = wbr_waddr ; wire [(`WB_FIFO_RAM_ADDR_LENGTH-1):0] wbr_whole_raddr = wbr_raddr ; wire wbw_read_enable = 1'b1 ; wire wbr_read_enable = 1'b1 ; `ifdef PCI_BIST wire scanb_so_internal ; // wires for connection of debug ports on two rams wire scanb_si_internal = scanb_so_internal ; `endif // instantiate and connect two generic rams - one for wishbone write fifo and one for wishbone read fifo pci_wb_tpram #(`WB_FIFO_RAM_ADDR_LENGTH, 40) wbw_fifo_storage ( // Generic synchronous two-port RAM interface .clk_a(wb_clock_in), .rst_a(reset_in), .ce_a(1'b1), .we_a(wbw_wallow), .oe_a(1'b1), .addr_a(wbw_whole_waddr), .di_a(dpram_portA_input), .do_a(), .clk_b(pci_clock_in), .rst_b(reset_in), .ce_b(wbw_read_enable), .we_b(1'b0), .oe_b(1'b1), .addr_b(wbw_whole_raddr), .di_b(40'h00_0000_0000), .do_b(dpram_portB_output) `ifdef PCI_BIST , .scanb_rst (scanb_rst), .scanb_clk (scanb_clk), .scanb_si (scanb_si), .scanb_so (scanb_so_internal), .scanb_en (scanb_en) `endif ); pci_wb_tpram #(`WB_FIFO_RAM_ADDR_LENGTH, 40) wbr_fifo_storage ( // Generic synchronous two-port RAM interface .clk_a(pci_clock_in), .rst_a(reset_in), .ce_a(1'b1), .we_a(wbr_wallow), .oe_a(1'b1), .addr_a(wbr_whole_waddr), .di_a(dpram_portB_input), .do_a(), .clk_b(wb_clock_in), .rst_b(reset_in), .ce_b(wbr_read_enable), .we_b(1'b0), .oe_b(1'b1), .addr_b(wbr_whole_raddr), .di_b(40'h00_0000_0000), .do_b(dpram_portA_output) `ifdef PCI_BIST , .scanb_rst (scanb_rst), .scanb_clk (scanb_clk), .scanb_si (scanb_si_internal), .scanb_so (scanb_so), .scanb_en (scanb_en) `endif ); `else // RAM blocks sharing between two fifos /*----------------------------------------------------------------------------------------------------------- Code section under this ifdef is used for implementation where RAM instances are too expensive. In this case one RAM instance is used for both - WISHBONE read and WISHBONE write fifo. -----------------------------------------------------------------------------------------------------------*/ /*----------------------------------------------------------------------------------------------------------- Address prefix definition - since both FIFOs reside in same RAM instance, storage is separated by MSB addresses. WISHBONE write fifo addresses are padded with zeros on the MSB side ( at least one address line must be used for this ), WISHBONE read fifo addresses are padded with ones on the right ( at least one ). -----------------------------------------------------------------------------------------------------------*/ wire [(`WB_FIFO_RAM_ADDR_LENGTH - WBW_ADDR_LENGTH - 1):0] wbw_addr_prefix = {( `WB_FIFO_RAM_ADDR_LENGTH - WBW_ADDR_LENGTH){1'b0}} ; wire [(`WB_FIFO_RAM_ADDR_LENGTH - WBR_ADDR_LENGTH - 1):0] wbr_addr_prefix = {( `WB_FIFO_RAM_ADDR_LENGTH - WBR_ADDR_LENGTH){1'b1}} ; /*----------------------------------------------------------------------------------------------------------- Port A address generation for RAM instance. RAM instance must be full two port RAM - read and write capability on both sides. Port A is clocked by WISHBONE clock, DIA is input for wbw_fifo, DOA is output for wbr_fifo. Address is multiplexed so operation can be switched between fifos. Default is a read on port. -----------------------------------------------------------------------------------------------------------*/ wire [(`WB_FIFO_RAM_ADDR_LENGTH-1):0] portA_addr = wbw_wallow ? {wbw_addr_prefix, wbw_waddr} : {wbr_addr_prefix, wbr_raddr} ; /*----------------------------------------------------------------------------------------------------------- Port B is clocked by PCI clock, DIB is input for wbr_fifo, DOB is output for wbw_fifo. Address is multiplexed so operation can be switched between fifos. Default is a read on port. -----------------------------------------------------------------------------------------------------------*/ wire [(`WB_FIFO_RAM_ADDR_LENGTH-1):0] portB_addr = wbr_wallow ? {wbr_addr_prefix, wbr_waddr} : {wbw_addr_prefix, wbw_raddr} ; wire portA_enable = 1'b1 ; wire portB_enable = 1'b1 ; // instantiate RAM for these two fifos pci_wb_tpram #(`WB_FIFO_RAM_ADDR_LENGTH, 40) wbu_fifo_storage ( // Generic synchronous two-port RAM interface .clk_a(wb_clock_in), .rst_a(reset_in), .ce_a(portA_enable), .we_a(wbw_wallow), .oe_a(1'b1), .addr_a(portA_addr), .di_a(dpram_portA_input), .do_a(dpram_portA_output), .clk_b(pci_clock_in), .rst_b(reset_in), .ce_b(portB_enable), .we_b(wbr_wallow), .oe_b(1'b1), .addr_b(portB_addr), .di_b(dpram_portB_input), .do_b(dpram_portB_output) `ifdef PCI_BIST , .scanb_rst (scanb_rst), .scanb_clk (scanb_clk), .scanb_si (scanb_si), .scanb_so (scanb_so), .scanb_en (scanb_en) `endif ); `endif /*----------------------------------------------------------------------------------------------------------- Instantiation of two control logic modules - one for WBW_FIFO and one for WBR_FIFO -----------------------------------------------------------------------------------------------------------*/ pci_wbw_fifo_control #(WBW_ADDR_LENGTH) wbw_fifo_ctrl ( .rclock_in(pci_clock_in), .wclock_in(wb_clock_in), .renable_in(wbw_renable_in), .wenable_in(wbw_wenable_in), .reset_in(reset_in), // .flush_in(wbw_flush_in), .almost_full_out(wbw_almost_full_out), .full_out(wbw_full_out), .empty_out(wbw_empty), .waddr_out(wbw_waddr), .raddr_out(wbw_raddr), .rallow_out(wbw_rallow), .wallow_out(wbw_wallow) ); pci_wbr_fifo_control #(WBR_ADDR_LENGTH) wbr_fifo_ctrl ( .rclock_in(wb_clock_in), .wclock_in(pci_clock_in), .renable_in(wbr_renable_in), .wenable_in(wbr_wenable_in), .reset_in(reset_in), .flush_in(wbr_flush_in), .empty_out(wbr_empty), .waddr_out(wbr_waddr), .raddr_out(wbr_raddr), .rallow_out(wbr_rallow), .wallow_out(wbr_wallow) ); // in and out transaction counters and grey codes reg [(WBW_ADDR_LENGTH-2):0] inGreyCount ; reg [(WBW_ADDR_LENGTH-2):0] outGreyCount ; wire [(WBW_ADDR_LENGTH-2):0] inNextGreyCount = {wbw_inTransactionCount[(WBW_ADDR_LENGTH-2)], wbw_inTransactionCount[(WBW_ADDR_LENGTH-2):1] ^ wbw_inTransactionCount[(WBW_ADDR_LENGTH-3):0]} ; wire [(WBW_ADDR_LENGTH-2):0] outNextGreyCount = {wbw_outTransactionCount[(WBW_ADDR_LENGTH-2)], wbw_outTransactionCount[(WBW_ADDR_LENGTH-2):1] ^ wbw_outTransactionCount[(WBW_ADDR_LENGTH-3):0]} ; // input transaction counter increment - when last data of transaction is written to fifo wire in_count_en = wbw_wallow && wbw_last_in ; // output transaction counter increment - when last data is on top of fifo and read from it wire out_count_en = wbw_renable_in && wbw_last_out ; // register holding grey coded count of incoming transactions always@(posedge wb_clock_in or posedge wbw_clear) begin if (wbw_clear) begin inGreyCount[(WBW_ADDR_LENGTH-2)] <= #`FF_DELAY 1'b1 ; inGreyCount[(WBW_ADDR_LENGTH-3):0] <= #`FF_DELAY {(WBW_ADDR_LENGTH-2),1'b0} ; end else if (in_count_en) inGreyCount <= #`FF_DELAY inNextGreyCount ; end wire [(WBW_ADDR_LENGTH-2):0] pci_clk_sync_inGreyCount ; reg [(WBW_ADDR_LENGTH-2):0] pci_clk_inGreyCount ; synchronizer_flop #((WBW_ADDR_LENGTH - 1)) i_synchronizer_reg_inGreyCount ( .data_in (inGreyCount), .clk_out (pci_clock_in), .sync_data_out (pci_clk_sync_inGreyCount), .async_reset (1'b0) ) ; always@(posedge pci_clock_in or posedge wbw_clear) begin if (wbw_clear) pci_clk_inGreyCount <= #`FF_DELAY 1 ; else pci_clk_inGreyCount <= # `FF_DELAY pci_clk_sync_inGreyCount ; end // register holding grey coded count of outgoing transactions always@(posedge pci_clock_in or posedge wbw_clear) begin if (wbw_clear) begin outGreyCount[(WBW_ADDR_LENGTH-2)] <= #`FF_DELAY 1'b1 ; outGreyCount[(WBW_ADDR_LENGTH-3):0] <= #`FF_DELAY {(WBW_ADDR_LENGTH-2),1'b0} ; end else if (out_count_en) outGreyCount <= #`FF_DELAY outNextGreyCount ; end // incoming transactions counter always@(posedge wb_clock_in or posedge wbw_clear) begin if (wbw_clear) wbw_inTransactionCount <= #`FF_DELAY {(WBW_ADDR_LENGTH-1){1'b0}} ; else if (in_count_en) wbw_inTransactionCount <= #`FF_DELAY wbw_inTransactionCount + 1'b1 ; end // outgoing transactions counter always@(posedge pci_clock_in or posedge wbw_clear) begin if (wbw_clear) wbw_outTransactionCount <= #`FF_DELAY {(WBW_ADDR_LENGTH-1){1'b0}} ; else if (out_count_en) wbw_outTransactionCount <= #`FF_DELAY wbw_outTransactionCount + 1'b1 ; end assign wbw_transaction_ready_out = pci_clk_inGreyCount != outGreyCount ; endmodule