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////////////////////////////////////////////////////////////////////// //// //// //// File name "wb_slave.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 1.1.1.1 2001/10/02 15:33:47 mihad // New project directory structure // // `include "bus_commands.v" `include "constants.v" `include "timescale.v" module WB_SLAVE( wb_clock_in, reset_in, wb_hit_in, wb_conf_hit_in, wb_map_in, wb_pref_en_in, wb_mrl_en_in, wb_addr_in, del_bc_in, wb_del_req_pending_in, wb_del_comp_pending_in, pci_drcomp_pending_in, del_bc_out, del_req_out, del_done_out, del_burst_out, del_write_out, del_write_in, del_error_in, del_in_progress_out, ccyc_addr_in, wb_del_addr_in, wb_del_be_in, wb_conf_offset_out, wb_conf_renable_out, wb_conf_wenable_out, wb_conf_be_out, wb_conf_data_in, wb_conf_data_out, wb_data_out, wb_cbe_out, wbw_fifo_wenable_out, wbw_fifo_control_out, wbw_fifo_almost_full_in, wbw_fifo_full_in, wbr_fifo_renable_out, wbr_fifo_be_in, wbr_fifo_data_in, wbr_fifo_control_in, wbr_fifo_flush_out, wbr_fifo_empty_in, pciw_fifo_empty_in, wbs_lock_in, CYC_I, STB_I, WE_I, SEL_I, SDATA_I, SDATA_O, ACK_O, RTY_O, ERR_O, CAB_I ); /*---------------------------------------------------------------------------------------------------------------------- Various parameters needed for state machine and other stuff ----------------------------------------------------------------------------------------------------------------------*/ parameter WBR_SEL = 1'b0 ; parameter CONF_SEL = 1'b1 ; `define FSM_BITS 3 parameter S_IDLE = `FSM_BITS'h0 ; parameter S_DEC1 = `FSM_BITS'h1 ; parameter S_DEC2 = `FSM_BITS'h2 ; parameter S_START = `FSM_BITS'h3 ; parameter S_W_ADDR_DATA = `FSM_BITS'h4 ; parameter S_READ = `FSM_BITS'h5 ; parameter S_CONF_WRITE = `FSM_BITS'h6 ; parameter S_CONF_READ = `FSM_BITS'h7 ; /*---------------------------------------------------------------------------------------------------------------------- System signals inputs wb_clock_in - WISHBONE bus clock input reset_in - system reset input controlled by bridge's reset logic ----------------------------------------------------------------------------------------------------------------------*/ input wb_clock_in, reset_in ; /*---------------------------------------------------------------------------------------------------------------------- Inputs from address decoding logic wb_hit_in - Decoder logic indicates if address is in a range of one of images wb_conf_hit_in - Decoder logic indicates that address is in configuration space range wb_map_in - Decoder logic provides information about image mapping - memory mapped image - wb_map_in = 0 IO space mapped image - wb_map_in = 1 wb_pref_en_in - Prefetch enable signal from currently selected image - used for PCI bus command usage wb_addr_in - Address already transalted from WB bus to PCI bus input wb_mrl_en_in - Memory read line enable input for each image ----------------------------------------------------------------------------------------------------------------------*/ input [4:0] wb_hit_in ; // hit indicators input wb_conf_hit_in ; // configuration hit indicator input [4:0] wb_pref_en_in ; // prefetch enable from all images input [4:0] wb_mrl_en_in ; // Memory Read line command enable from images input [4:0] wb_map_in ; // address space mapping indicators - 1 memory space mapping, 0-IO space mapping input [31:0] wb_addr_in ; // Translated address input /*---------------------------------------------------------------------------------------------------------------------- Delayed transaction control inputs and outputs: Used for locking particular accesses when delayed transactions are in progress: wb_del_addr_in - delayed transaction address input - when completion is ready it's used for transaction decoding wb_del_be_in - delayed transaction byte enable input - when completion is ready it's used for transaction decoding ----------------------------------------------------------------------------------------------------------------------*/ input [31:0] wb_del_addr_in ; input [3:0] wb_del_be_in ; input [3:0] del_bc_in ; // delayed request bus command used input wb_del_req_pending_in ; // delayed request pending indicator input wb_del_comp_pending_in ; // delayed completion pending indicator input pci_drcomp_pending_in ; // PCI initiated delayed read completion pending output [3:0] del_bc_out ; // delayed transaction bus command output output del_req_out ; // output for issuing delayed transaction requests output del_done_out ; // output indicating current delayed completion finished on WISHBONE bus output del_burst_out ; // delayed burst transaction indicator output del_in_progress_out ; // delayed in progress indicator - since delayed transaction can be a burst transaction, progress indicator must be used for proper operation output del_write_out ; // write enable for delayed transaction - used for indicating that transaction is a write input del_write_in ; // indicates that current delayed completion is from a write request input del_error_in ; // indicate that delayed request terminated with an error - used for write requests input [31:0] ccyc_addr_in ; // configuration cycle address input - it's separate from other addresses, since it is stored separately and decoded for type 0 configuration access /*---------------------------------------------------------------------------------------------------------------------- Configuration space access control and data signals wb_conf_offset_out - lower 12 bits of address input provided for register offset wb_conf_renable - read enable signal for configuration space accesses wb_conf_wenable - write enable signal for configuration space accesses wb_conf_be_out - byte enable signals for configuration space accesses wb_conf_data_in - data from configuration space wb_conf_data_in - data provided for configuration space ----------------------------------------------------------------------------------------------------------------------*/ output [11:0] wb_conf_offset_out ; // register offset output output wb_conf_renable_out, // configuration read and write enable outputs wb_conf_wenable_out ; output [3:0] wb_conf_be_out ; // byte enable outputs for configuration space input [31:0] wb_conf_data_in ; // configuration data input from configuration space output [31:0] wb_conf_data_out ; // configuration data output for configuration space /*---------------------------------------------------------------------------------------------------------------------- Data from WISHBONE bus output to interiror of the core: Data output is used for normal and configuration accesses. ---------------------------------------------------------------------------------------------------------------------*/ output [31:0] wb_data_out ; /*---------------------------------------------------------------------------------------------------------------------- Bus command - byte enable output - during address phase of image access this bus holds information about PCI bus command that should be used, during dataphases ( configuration or image access ) this bus contains inverted SEL_I signals ---------------------------------------------------------------------------------------------------------------------*/ output [3:0] wb_cbe_out ; /*---------------------------------------------------------------------------------------------------------------------- WBW_FIFO control signals used for sinking data into WBW_FIFO and status monitoring ---------------------------------------------------------------------------------------------------------------------*/ output wbw_fifo_wenable_out ; // write enable for WBW_FIFO output output [3:0] wbw_fifo_control_out ; // control bus output for WBW_FIFO input wbw_fifo_almost_full_in ; // almost full status indicator from WBW_FIFO input wbw_fifo_full_in ; // full status indicator from WBW_FIFO /*---------------------------------------------------------------------------------------------------------------------- WBR_FIFO control signals used for fetching data from WBR_FIFO and status monitoring ---------------------------------------------------------------------------------------------------------------------*/ output wbr_fifo_renable_out ; // WBR_FIFO read enable output input [3:0] wbr_fifo_be_in ; // byte enable input from WBR_FIFO input [31:0] wbr_fifo_data_in ; // data input from WBR_FIFO input [3:0] wbr_fifo_control_in ; // control bus input from WBR_FIFO output wbr_fifo_flush_out ; // flush signal for WBR_FIFO input wbr_fifo_empty_in ; // empty status indicator from WBR_FIFO // used for transaction ordering requirements - WISHBONE read cannot complete until writes from PCI are completed input pciw_fifo_empty_in ; // empty status indicator from PCIW_FIFO /*---------------------------------------------------------------------------------------------------------------------- wbs_lock_in - internal signal - when error reporting is enabled and PCI master detects an error while completing posted write on PCI, then WISHBONE slave unit doesn't accept any new requests or posted writes. Delayed completions are allowed to complete on WISHBONE if all other requirements are satisfied also. ---------------------------------------------------------------------------------------------------------------------*/ input wbs_lock_in ; /*---------------------------------------------------------------------------------------------------------------------- WISHBONE bus interface signals - can be connected directly to WISHBONE bus ---------------------------------------------------------------------------------------------------------------------*/ input CYC_I ; // cycle indicator input STB_I ; // strobe input - input data is valid when strobe and cycle indicator are high input WE_I ; // write enable input - 1 - write operation, 0 - read operation input [3:0] SEL_I ; // Byte select inputs input [31:0] SDATA_I ; // WISHBONE slave interface input data bus output [31:0] SDATA_O ; // WISHBONE slave interface output data bus output ACK_O ; // Acknowledge output - qualifies valid data on data output bus or received data on data input bus output RTY_O ; // retry output - signals to WISHBONE master that cycle should be terminated and retried later output ERR_O ; // Signals to WISHBONE master that access resulted in an error input CAB_I ; // consecutive address burst input - indicates that master will do a serial address transfer in current cycle reg [(`FSM_BITS - 1):0] c_state ; //current state register // synopsys state_vector c_state reg [(`FSM_BITS - 1):0] n_state ; //next state input to current state register // lock register - lock signal can cross clock domains, so here is register for it reg lock ; always@(posedge reset_in or posedge wb_clock_in) begin if (reset_in) lock <= #`FF_DELAY 1'b0 ; else lock <= #`FF_DELAY wbs_lock_in ; end // state machine register control always@(posedge wb_clock_in or posedge reset_in) begin if (reset_in) c_state <= #`FF_DELAY S_IDLE ; else c_state <= #`FF_DELAY n_state ; end // write operation indicator for delayed transaction requests assign del_write_out = WE_I ; // variable for bus command multiplexer logic output for delayed requests reg [3:0] del_bc ; //register for intermediate data and select storage reg [35:0] d_incoming ; // enable for incoming data register reg d_incoming_ena ; // incoming data register control logic always@(posedge wb_clock_in or posedge reset_in) begin if (reset_in) d_incoming <= #`FF_DELAY {35{1'b0}} ; else if (d_incoming_ena) d_incoming <= #`FF_DELAY {SEL_I, SDATA_I} ; end /*=================================================================================================================================================================================== Write allow for image accesses. Writes through images are allowed when all of following are true: - WBW_FIFO musn't be almost full nor full for image writes to be allowed - Every transaction takes at least two locations in the FIFO - delayed read from from WISHBONE to PCI request musn't be present - delayed read from PCI to WISHBONE completion musn't be present - lock input musn't be set - it can be set because of error reporting or because PCI master state machine is disabled ===================================================================================================================================================================================*/ wire wimg_wallow = ~|{ wbw_fifo_almost_full_in , wbw_fifo_full_in, wb_del_req_pending_in, pci_drcomp_pending_in, lock } ; reg decode_en ; reg img_wallow ; always@(posedge reset_in or posedge wb_clock_in) begin if (reset_in) img_wallow <= #`FF_DELAY 1'b0 ; else if (decode_en) img_wallow <= #`FF_DELAY wimg_wallow ; end /*=================================================================================================================================================================================== WISHBONE slave can request an image read accesses when all of following are true: - delayed completion is not present - delayed request is not present - operation is not locked because of error reporting mechanism or because PCI master is disabled ===================================================================================================================================================================================*/ wire wdo_del_request = ~|{ wb_del_req_pending_in, wb_del_comp_pending_in, lock } ; reg do_del_request ; always@(posedge reset_in or posedge wb_clock_in) begin if (reset_in) do_del_request <= #`FF_DELAY 1'b0 ; else if (decode_en) do_del_request <= #`FF_DELAY wdo_del_request ; end /*=================================================================================================================================================================================== WISHBONE slave can complete an image read accesses when all of following are true: - delayed read completion is present - delayed read completion is the same as current read access ( dread_completion_hit is 1 ) - PCI Write FIFO is empty - no posted write is waiting to be finished in PCIW_FIFO - WBR_FIFO empty status is active ===================================================================================================================================================================================*/ wire del_bc_hit = ( del_bc == del_bc_in ) ; wire wdel_addr_hit = ( wb_del_addr_in == wb_addr_in ) && ( SEL_I == wb_del_be_in ) ; reg del_addr_hit ; always@(posedge reset_in or posedge wb_clock_in) begin if (reset_in) del_addr_hit <= #`FF_DELAY 1'b0 ; else if ( decode_en ) del_addr_hit <= #`FF_DELAY wdel_addr_hit ; end wire wdel_completion_allow = wb_del_comp_pending_in && ((~del_write_in && ~WE_I && pciw_fifo_empty_in && ~wbr_fifo_empty_in) || (del_write_in && WE_I)) ; reg del_completion_allow ; always@(posedge reset_in or posedge wb_clock_in) begin if (reset_in) del_completion_allow <= #`FF_DELAY 1'b0 ; else if ( decode_en ) del_completion_allow <= #`FF_DELAY wdel_completion_allow ; end wire do_dread_completion = del_completion_allow && del_bc_hit && del_addr_hit ; // address allignement indicator wire alligned_address = ~|(wb_addr_in[1:0]) ; `ifdef GUEST // wires indicating allowance for configuration cycle generation requests wire do_ccyc_req = 1'b0 ; wire do_ccyc_comp = 1'b0 ; // wires indicating allowance for interrupt acknowledge cycle generation requests wire do_iack_req = 1'b0 ; wire do_iack_comp = 1'b0 ; // variables for configuration access control signals reg conf_wenable ; assign wb_conf_wenable_out = 1'b0 ; // configuration cycle data register hit wire ccyc_hit = 1'b0 ; wire iack_hit = 1'b0 ; `else `ifdef HOST // only host implementation has access for generating interrupt acknowledge and configuration cycles // configuration cycle data register hit wire wccyc_hit = (wb_addr_in[8:2] == {1'b1, `CNF_DATA_ADDR}) && alligned_address ; reg ccyc_hit ; always@(posedge reset_in or posedge wb_clock_in) begin if (reset_in) ccyc_hit <= #`FF_DELAY 1'b0 ; else if (decode_en) ccyc_hit <= #`FF_DELAY wccyc_hit ; end wire wiack_hit = (wb_addr_in[8:2] == {1'b1, `INT_ACK_ADDR}) && alligned_address ; reg iack_hit ; always@(posedge reset_in or posedge wb_clock_in) begin if (reset_in) iack_hit <= #`FF_DELAY 1'b0 ; else if (decode_en) iack_hit <= #`FF_DELAY wiack_hit ; end // wires indicating allowance for configuration cycle generation requests wire do_ccyc_req = do_del_request && ccyc_hit; wire do_ccyc_comp = del_completion_allow && del_bc_hit && ccyc_hit; // wires indicating allowance for interrupt acknowledge cycle generation requests wire do_iack_req = do_del_request && iack_hit ; wire do_iack_comp = del_completion_allow && del_bc_hit && ccyc_hit; // variables for configuration access control signals reg conf_wenable ; assign wb_conf_wenable_out = conf_wenable ; `endif `endif // configuration read enable - supplied for host and guest bridges reg conf_renable ; assign wb_conf_renable_out = conf_renable ; // wire for write attempt - 1 when external WB master is attempting a write wire wattempt = ( CYC_I && STB_I && WE_I ) ; // write is qualified when cycle, strobe and write enable inputs are all high // wire for read attempt - 1 when external WB master is attempting a read wire rattempt = ( CYC_I && STB_I && ~WE_I ) ; // read is qualified when cycle and strobe are high and write enable is low // burst access indicator wire burst_transfer = CYC_I && CAB_I ; // SEL_I error indicator for IO and configuration accesses - select lines must be alligned with address reg sel_error ; always@(wb_addr_in or SEL_I) begin case (wb_addr_in[1:0]) 2'b00: sel_error = ~SEL_I[0] ; // select 0 must be 1, all others are don't cares. 2'b01: sel_error = ~SEL_I[1] || SEL_I[0] ; // byte 0 can't be selected, byte 1 must be selected 2'b10: sel_error = ~SEL_I[2] || SEL_I[1] || SEL_I[0] ; // bytes 0 and 1 can't be selected, byte 2 must be selected 2'b11: sel_error = ~SEL_I[3] || SEL_I[2] || SEL_I[1] || SEL_I[0] ; // bytes 0, 1 and 2 can't be selected, byte 3 must be selected endcase end // WBW_FIFO control output reg [3:0] wbw_fifo_control ; assign wbw_fifo_control_out = wbw_fifo_control ; //control bus output for WBW_FIFO // WBW_FIFO wenable output assignment reg wbw_fifo_wenable ; assign wbw_fifo_wenable_out = wbw_fifo_wenable ; //write enable for WBW_FIFO // WBR_FIFO control outputs reg wbr_fifo_flush, wbr_fifo_renable ; // flush and read enable outputs assign wbr_fifo_renable_out = wbr_fifo_renable ; //read enable for wbr_fifo reg wbr_fifo_flush_out ; always@(posedge reset_in or posedge wb_clock_in) begin if ( reset_in ) wbr_fifo_flush_out <= #`FF_DELAY 1'b0 ; else wbr_fifo_flush_out <= #`FF_DELAY wbr_fifo_flush ; end // delayed transaction request control signals reg del_req, del_done ; assign del_req_out = del_req ; // read request assign del_done_out = del_done ; // read done // WISHBONE handshaking control outputs reg ack, rty, err ; assign ACK_O = ack ; assign RTY_O = rty ; assign ERR_O = err ; /*---------------------------------------------------------------------------------------------------------------------- Control logic for image hits img_hit - state of wb_hit_in bus when first data is acknowledged ---------------------------------------------------------------------------------------------------------------------*/ reg [4:0] img_hit ; always@(posedge wb_clock_in or posedge reset_in) begin if (reset_in) img_hit <= #`FF_DELAY 5'h00 ; else if (decode_en) img_hit <= #`FF_DELAY wb_hit_in ; end wire wb_hit = |( img_hit ) ; /*---------------------------------------------------------------------------------------------------------------------- Control logic for image control signals pref_en - prefetch enable of currently selected image mrl_en - Memory read line enable of currently selected image map - Address space mapping for currently selected image ---------------------------------------------------------------------------------------------------------------------*/ reg pref_en, mrl_en, map ; wire wpref_en = |(wb_pref_en_in & wb_hit_in) ; wire wmrl_en = |(wb_pref_en_in & wb_hit_in) ; wire wmap = |(wb_map_in & wb_hit_in) ; always@(posedge reset_in or posedge wb_clock_in) begin if (reset_in) begin pref_en <= #`FF_DELAY 1'b0 ; mrl_en <= #`FF_DELAY 1'b0 ; map <= #`FF_DELAY 1'b0 ; end else if ( decode_en ) begin pref_en <= #`FF_DELAY wpref_en ; mrl_en <= #`FF_DELAY wmrl_en ; map <= #`FF_DELAY wmap ; end end assign del_burst_out = CAB_I && pref_en && ~WE_I; // delayed burst indicator - only when WB master attempts CAB transfer and prefetch enable of corresponding image is set - // applies for reads only - delayed write cannot be a burst reg wb_conf_hit ; always@(posedge reset_in or posedge wb_clock_in) begin if (reset_in) wb_conf_hit <= #`FF_DELAY 1'b0 ; else if (decode_en) wb_conf_hit <= #`FF_DELAY wb_conf_hit_in ; end /*---------------------------------------------------------------------------------------------------------------------- Delayed transaction bus command generation Bus command for delayed reads depends on image's address space mapping and control bits and whether or not these are interrupt acknowledge requests or configuration cycle requests ---------------------------------------------------------------------------------------------------------------------*/ assign del_bc_out = del_bc ; always@(map or mrl_en or ccyc_hit or WE_I or wb_conf_hit or CAB_I or pref_en) begin if (wb_conf_hit) begin case( {ccyc_hit, WE_I} ) 2'b11: del_bc = `BC_CONF_WRITE ; 2'b10: del_bc = `BC_CONF_READ ; 2'b01: del_bc = `BC_IACK ; 2'b00: del_bc = `BC_IACK ; endcase end else begin case ( {map, CAB_I && mrl_en && pref_en} ) 2'b11: del_bc = `BC_IO_READ ; 2'b10: del_bc = `BC_IO_READ ; 2'b01: del_bc = `BC_MEM_READ_LN ; 2'b00: del_bc = `BC_MEM_READ ; endcase end end // WISHBONE data output select lines for output multiplexor reg sdata_o_sel ; reg del_in_progress_out ; // state machine indicates whether current read completion is in progress on WISHBONE bus wire image_access_error = (map && (burst_transfer || sel_error)) || // IO write is a burst or has wrong select lines active= Error (~map && ~alligned_address) ; // Mem write to nonaligned address = error; `ifdef HOST reg [1:0] wbw_data_out_sel ; parameter SEL_ADDR_IN = 2'b10 ; parameter SEL_CCYC_ADDR = 2'b11 ; parameter SEL_DATA_IN = 2'b00 ; `else `ifdef GUEST reg wbw_data_out_sel ; parameter SEL_ADDR_IN = 1'b1 ; parameter SEL_DATA_IN = 1'b0 ; `endif `endif // state machine logic always@( c_state or wattempt or img_wallow or burst_transfer or wb_hit or map or alligned_address or rattempt or do_dread_completion or wbr_fifo_control_in or wb_conf_hit or do_ccyc_req or do_ccyc_comp or ccyc_hit or del_error_in or do_iack_req or do_iack_comp or iack_hit or image_access_error or wbw_fifo_almost_full_in or do_del_request or wbr_fifo_empty_in ) begin // default signal values // response signals inactive ack = 1'b0 ; rty = 1'b0 ; err = 1'b0 ; //write signals inactive wbw_fifo_control[`ADDR_CTRL_BIT] = 1'b1 ; wbw_fifo_control[`DATA_ERROR_CTRL_BIT] = 1'b0 ; wbw_fifo_control[`LAST_CTRL_BIT] = 1'b0 ; wbw_fifo_control[`UNUSED_CTRL_BIT] = 1'b0 ; wbw_fifo_wenable = 1'b0 ; d_incoming_ena = 1'b0 ; // read signals inactive wbr_fifo_flush = 1'b0 ; wbr_fifo_renable = 1'b0 ; del_req = 1'b0 ; del_done = 1'b0 ; // configuration space control signals inactive conf_wenable = 1'b0 ; conf_renable = 1'b0 ; // WISHBONE data output selection - drive wbr output sdata_o_sel = WBR_SEL ; // read is not in progress del_in_progress_out = 1'b0 ; decode_en = 1'b0 ; wbw_data_out_sel = SEL_ADDR_IN ; case (c_state) S_IDLE: begin if ( wattempt || rattempt ) begin `ifdef WB_DECODE_FAST decode_en = 1'b1 ; n_state = S_START ; `else n_state = S_DEC1 ; `endif end else n_state = S_IDLE ; end S_DEC1: begin if ( wattempt || rattempt ) begin `ifdef WB_DECODE_MEDIUM decode_en = 1'b1 ; n_state = S_START ; `else n_state = S_DEC2 ; `endif end else n_state = S_IDLE ; end S_DEC2: begin if ( wattempt || rattempt ) begin decode_en = 1'b1 ; n_state = S_START ; end else n_state = S_IDLE ; end S_START:begin if (wb_conf_hit) // configuration space hit begin if ( wattempt ) n_state = S_CONF_WRITE ; // go to conf. write state else if ( rattempt ) begin n_state = S_CONF_READ ; // go to conf. read state if(~(ccyc_hit || iack_hit)) sdata_o_sel = CONF_SEL ; end else n_state = S_IDLE ; // master terminated - go back to idle state end // wb_conf_hit*/ else if(wb_hit && (wattempt || rattempt)) begin // check error conditions for image writes or reads if ( image_access_error ) begin n_state = S_IDLE ; // go back to idle state because of an error condition err = 1'b1 ; end // error conditions else // check for retry conditions for image writes or reads if ( (wattempt && ~img_wallow) || (rattempt && ~do_dread_completion) // write to image not allowed, no read ready yet - retry ) begin n_state = S_IDLE ; // go back to IDLE rty = 1'b1 ; del_req = do_del_request && rattempt ; end //retry else // everything OK - proceed if ( wattempt ) begin n_state = S_W_ADDR_DATA ; // goto write transfer state // respond with acknowledge ack = 1'b1 ; wbw_fifo_wenable = 1'b1 ; // data is latched to data incoming intermidiate stage - it will be put in FIFO later d_incoming_ena = 1'b1 ; end else begin err = wbr_fifo_control_in[`DATA_ERROR_CTRL_BIT] ; ack = ~wbr_fifo_control_in[`DATA_ERROR_CTRL_BIT] ; wbr_fifo_renable = 1'b1 ; del_in_progress_out = 1'b1 ; if ( wbr_fifo_control_in[`DATA_ERROR_CTRL_BIT] || wbr_fifo_control_in[`LAST_CTRL_BIT] ) begin n_state = S_IDLE ; // go back to idle state // respond that read is finished del_done = 1'b1 ; end // end read else n_state = S_READ ; // go to read state end end else n_state = S_IDLE ; end S_W_ADDR_DATA: begin wbw_data_out_sel = SEL_DATA_IN ; err = burst_transfer && wattempt && ~alligned_address ; rty = burst_transfer && wattempt && wbw_fifo_almost_full_in ; if ( ~burst_transfer || wattempt && ( ~alligned_address || wbw_fifo_almost_full_in) ) begin n_state = S_IDLE ; // write last data to FIFO and don't latch new data wbw_fifo_control[`ADDR_CTRL_BIT] = 1'b0 ; wbw_fifo_control[`LAST_CTRL_BIT] = 1'b1 ; wbw_fifo_wenable = 1'b1 ; end else begin n_state = S_W_ADDR_DATA ; wbw_fifo_control[`ADDR_CTRL_BIT] = 1'b0 ; wbw_fifo_control[`LAST_CTRL_BIT] = 1'b0 ; ack = wattempt ; wbw_fifo_wenable = wattempt ; d_incoming_ena = wattempt ; end end // S_W_ADDR_DATA S_READ:begin // this state is for reads only - in this state read is in progress all the time del_in_progress_out = 1'b1 ; ack = burst_transfer && rattempt && ~wbr_fifo_control_in[`DATA_ERROR_CTRL_BIT] && alligned_address && ~wbr_fifo_empty_in ; err = burst_transfer && rattempt && ((wbr_fifo_control_in[`DATA_ERROR_CTRL_BIT] || ~alligned_address) && ~wbr_fifo_empty_in) ; rty = burst_transfer && rattempt && wbr_fifo_empty_in && alligned_address ; // if acknowledge is beeing signalled then enable read from wbr fifo wbr_fifo_renable = burst_transfer && rattempt && alligned_address && ~wbr_fifo_empty_in ; if ( ~burst_transfer || rattempt && (~alligned_address || wbr_fifo_empty_in || wbr_fifo_control_in[`DATA_ERROR_CTRL_BIT] || wbr_fifo_control_in[`LAST_CTRL_BIT]) ) begin n_state = S_IDLE ; del_done = 1'b1 ; wbr_fifo_flush = ~wbr_fifo_empty_in && ~(wbr_fifo_control_in[`DATA_ERROR_CTRL_BIT] || wbr_fifo_control_in[`LAST_CTRL_BIT]) ; end else begin n_state = S_READ ; end end // S_READ S_CONF_WRITE: begin `ifdef HOST wbw_data_out_sel = SEL_CCYC_ADDR ; `endif n_state = S_IDLE ; // next state after configuration access is always idle del_req = do_ccyc_req && ~burst_transfer ; del_done = do_ccyc_comp && ~burst_transfer ; del_in_progress_out = do_ccyc_comp && ~burst_transfer ; if ( burst_transfer || ~alligned_address ) begin err = 1'b1 ; end else begin if ( do_ccyc_req || (ccyc_hit && ~do_ccyc_comp)) begin rty = 1'b1 ; end else if ( do_ccyc_comp ) begin err = del_error_in ; ack = ~del_error_in ; end else begin ack = ~ccyc_hit ; conf_wenable = ~ccyc_hit ; end end end // S_CONF_WRITE S_CONF_READ: begin `ifdef HOST wbw_data_out_sel = SEL_CCYC_ADDR ; `endif n_state = S_IDLE ; // next state after configuration access is always idle del_req = ~burst_transfer && ( do_ccyc_req || do_iack_req ); del_done = ~burst_transfer && ( do_ccyc_comp || do_iack_comp ) ; del_in_progress_out = ~burst_transfer && ( do_ccyc_comp || do_iack_comp ) ; wbr_fifo_renable = ~burst_transfer && ( do_ccyc_comp || do_iack_comp ) ; if ( ~(ccyc_hit || iack_hit) ) sdata_o_sel = CONF_SEL ; if ( burst_transfer || ~alligned_address ) begin err = 1'b1 ; end else begin if ( do_ccyc_req || ( ccyc_hit && ~do_ccyc_comp )) begin rty = 1'b1 ; end else if ( do_iack_req || ( iack_hit && ~do_iack_comp )) begin rty = 1'b1 ; end else if ( do_iack_comp || do_ccyc_comp ) begin err = del_error_in ; ack = ~del_error_in ; end else begin ack = ~( ccyc_hit || iack_hit ) ; conf_renable = ~( ccyc_hit || iack_hit ) ; end end end //S_CONF_READ default:begin n_state = S_IDLE ; // return to idle state end //default endcase end // configuration space offset output assignment assign wb_conf_offset_out = {wb_addr_in[11:2], 2'b00} ; // upper 10 bits of address input and two zeros // Configuration space byte enables output assign wb_conf_be_out = SEL_I ; // just route select lines from WISHBONE to conf space // data output assignment - for image writes, first data is address, subsequent data comes from intermediate register reg [31:0] wb_data_out ; `ifdef HOST always@(wbw_data_out_sel or wb_addr_in or ccyc_addr_in or d_incoming) begin case ( wbw_data_out_sel ) SEL_CCYC_ADDR: wb_data_out = ccyc_addr_in ; SEL_DATA_IN: wb_data_out = d_incoming ; default: wb_data_out = wb_addr_in ; endcase end `else `ifdef GUEST always@(wbw_data_out_sel or wb_addr_in or d_incoming) begin if ( wbw_data_out_sel ) wb_data_out = wb_addr_in ; else wb_data_out = d_incoming ; end `endif `endif // command / byte enable assignment - with address, bus command is provided, with data - byte enables are provided reg [3:0] wb_cbe ; assign wb_cbe_out = wb_cbe ; always@(wbw_data_out_sel or d_incoming or map) begin if (wbw_data_out_sel && map) wb_cbe = `BC_IO_WRITE ; else if (wbw_data_out_sel) wb_cbe = `BC_MEM_WRITE ; else wb_cbe = ~(d_incoming[35:32]) ; end // for configuration writes, data output is always data from WISHBONE - in guest implementation data is all 0. `ifdef GUEST assign wb_conf_data_out = 32'h00000000 ; `else `ifdef HOST assign wb_conf_data_out = SDATA_I ; `endif `endif // WISHBONE data output multiplexor reg [31:0] sdata ; assign SDATA_O = sdata ; always@(sdata_o_sel or wbr_fifo_data_in or wb_conf_data_in) begin case (sdata_o_sel) WBR_SEL :sdata = wbr_fifo_data_in ; CONF_SEL:sdata = wb_conf_data_in ; endcase end endmodule //WB_SLAVE
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