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//////////////////////////////////////////////////////////////////////
////                                                              ////
////  File name: pci_target32_sm.v                                ////
////                                                              ////
////  This file is part of the "PCI bridge" project               ////
////  http://www.opencores.org/cores/pci/                         ////
////                                                              ////
////  Author(s):                                                  ////
////      - Tadej Markovic, tadej@opencores.org                   ////
////                                                              ////
////  All additional information is avaliable in the README.txt   ////
////  file.                                                       ////
////                                                              ////
////                                                              ////
//////////////////////////////////////////////////////////////////////
////                                                              ////
//// Copyright (C) 2000 Tadej Markovic, tadej@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 1.4  2002/02/19 16:32:37  mihad
// Modified testbench and fixed some bugs
//
// Revision 1.3  2002/02/01 15:25:12  mihad
// Repaired a few bugs, updated specification, added test bench files and design document
//
// Revision 1.2  2001/10/05 08:14:30  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
//
//
 
`define P_FSM_BITS 2 // number of bits needed for FSM states
 
`include "pci_constants.v"
 
// synopsys translate_off
`include "timescale.v"
// synopsys translate_on
 
module PCI_TARGET32_SM
(
    // system inputs
    clk_in,
    reset_in,
    // master inputs
    pci_frame_in,
    pci_irdy_in,
    pci_idsel_in,
    pci_frame_reg_in,
    pci_irdy_reg_in,
    pci_idsel_reg_in,
    // target response outputs
    pci_trdy_out,
    pci_stop_out,
    pci_devsel_out,
    pci_trdy_en_out,
    pci_stop_en_out,
    pci_devsel_en_out,
    ad_load_out,
    ad_load_on_transfer_out,
    // address, data, bus command, byte enable in/outs
    pci_ad_reg_in,
    pci_ad_out,
    pci_ad_en_out,
    pci_cbe_reg_in,
    bckp_trdy_en_in,
    bckp_devsel_in,
    bckp_trdy_in,
    bckp_stop_in,
    pci_trdy_reg_in,
    pci_stop_reg_in,
 
    // backend side of state machine with control signals to pci_io_mux ...
    address_out,
    addr_claim_in,
    bc_out,
    bc0_out,
    data_out,
    data_in,
    be_out,
    req_out,
    rdy_out,
    addr_phase_out,
    bckp_devsel_out,
    bckp_trdy_out,
    bckp_stop_out,
    last_reg_out,
    frame_reg_out,
    fetch_pcir_fifo_out,
    load_medium_reg_out,
    sel_fifo_mreg_out,
    sel_conf_fifo_out,
    fetch_conf_out,
    load_to_pciw_fifo_out,
    load_to_conf_out,
    same_read_in,
    norm_access_to_config_in,
    read_completed_in,
    read_processing_in,
    target_abort_in,
    disconect_wo_data_in,
    disconect_w_data_in,
    target_abort_set_out,
    pciw_fifo_full_in,
    pcir_fifo_data_err_in,
    wbw_fifo_empty_in,
    wbu_del_read_comp_pending_in,
    wbu_frame_en_in
 
) ;
 
/*----------------------------------------------------------------------------------------------------------------------
Various parameters needed for state machine and other stuff
----------------------------------------------------------------------------------------------------------------------*/
parameter       S_IDLE          = `P_FSM_BITS'h0 ;
parameter       S_WAIT          = `P_FSM_BITS'h1 ;
parameter       S_TRANSFERE     = `P_FSM_BITS'h2 ;
 
 
/*==================================================================================================================
System inputs.
==================================================================================================================*/
// PCI side clock and reset
input   clk_in,
        reset_in ;
 
 
/*==================================================================================================================
PCI interface signals - bidirectional signals are divided to inputs and outputs in I/O cells instantiation
module. Enables are separate signals.
==================================================================================================================*/
// master inputs
input   pci_frame_in,
        pci_irdy_in,
        pci_idsel_in ;
input   pci_frame_reg_in,
        pci_irdy_reg_in,
        pci_idsel_reg_in ;
 
// target response outputs
output  pci_trdy_out,
        pci_stop_out,
        pci_devsel_out ;
output  pci_trdy_en_out,
        pci_stop_en_out,
        pci_devsel_en_out ;
output  ad_load_out ;
output  ad_load_on_transfer_out ;
// address, data, bus command, byte enable in/outs
input   [31:0]  pci_ad_reg_in ;
output  [31:0]  pci_ad_out ;
output          pci_ad_en_out ;
input   [3:0]   pci_cbe_reg_in ;
input           bckp_trdy_en_in ;
input           bckp_devsel_in ;
input           bckp_trdy_in ;
input           bckp_stop_in ;
input           pci_trdy_reg_in ;
input           pci_stop_reg_in ;
 
 
/*==================================================================================================================
Other side of PCI Target state machine
==================================================================================================================*/
// Data, byte enables, bus commands and address ports
output  [31:0]  address_out ;       // current request address output - registered
input           addr_claim_in ;     // current request address claim input
output  [3:0]   bc_out ;            // current request bus command output - registered
output          bc0_out ;           // current cycle RW signal output
input   [31:0]  data_in ;           // for read operations - current dataphase data input
output  [31:0]  data_out ;          // for write operations - current request data output - registered
output   [3:0]  be_out ;            // current dataphase byte enable outputs - registered
// Port connection control signals from PCI FSM
output          req_out ;           // Read is requested to WB master
output          rdy_out ;           // DATA / ADDRESS selection when read or write - registered
output          addr_phase_out ;    // Indicates address phase and also fast-back-to-back address phase - registered
output                  bckp_devsel_out ;       // DEVSEL output (which is registered) equivalent
output          bckp_trdy_out ;     // TRDY output (which is registered) equivalent
output                  bckp_stop_out ;         // STOP output (which is registered) equivalent
output          last_reg_out ;      // Indicates last data phase - registered
output          frame_reg_out ;     // FRAME output signal - registered
output          fetch_pcir_fifo_out ;// Read enable for PCIR_FIFO when when read is finishen on WB side
output          load_medium_reg_out ;// Load data from PCIR_FIFO to medium register (first data must be prepared on time)
output          sel_fifo_mreg_out ; // Read data selection between PCIR_FIFO and medium register
output          sel_conf_fifo_out ; // Read data selection between Configuration registers and "FIFO"
output          fetch_conf_out ;    // Read enable for configuration space registers
output          load_to_pciw_fifo_out ;// Write enable to PCIW_FIFO
output          load_to_conf_out ;  // Write enable to Configuration space registers
 
 
/*==================================================================================================================
Status
==================================================================================================================*/
input           same_read_in ;              // Indicates the same read request (important when read is finished on WB side)
input           norm_access_to_config_in ;  // Indicates the access to Configuration space with MEMORY commands
input           read_completed_in ;         // Indicates that read request is completed on WB side
input           read_processing_in ;        // Indicates that read request is processing on WB side
input           target_abort_in ;           // Indicates target abort termination
input           disconect_wo_data_in ;      // Indicates disconnect without data termination
input                   disconect_w_data_in ;           // Indicates disconnect with data termination
input           pciw_fifo_full_in ;         // Indicates that write PCIW_FIFO is full
input           pcir_fifo_data_err_in ;     // Indicates data error on current data read from PCIR_FIFO
input           wbw_fifo_empty_in ;         // Indicates that WB SLAVE UNIT has no data to be written to PCI bus
input                   wbu_del_read_comp_pending_in ; // Indicates that WB S�AVE UNIT has a delayed read pending
input           wbu_frame_en_in ;           // Indicates that WB SLAVE UNIT is accessing the PCI bus (important if
                                            //   address on PCI bus is also claimed by decoder in this PCI TARGET UNIT
output          target_abort_set_out ;      // Signal used to be set in configuration space registers
 
/*==================================================================================================================
END of input / output PORT DEFINITONS !!!
==================================================================================================================*/
 
// Delayed frame signal for determining the address phase
reg             previous_frame ;
// Delayed read completed signal for preparing the data from pcir fifo
reg             read_completed_reg ;
// Delayed disconnect with/without data for stop loading data to PCIW_FIFO
//reg             disconect_wo_data_reg ;
 
wire config_disconnect ;
wire disconect_wo_data = disconect_wo_data_in || config_disconnect ;
wire disconect_w_data = disconect_w_data_in ;
// Delayed frame signal for determining the address phase!
always@(posedge clk_in or posedge reset_in)
begin
    if (reset_in)
    begin
        previous_frame <= #`FF_DELAY 1'b1 ;
        read_completed_reg <= #`FF_DELAY 1'b0 ;
    end
    else
    begin
        previous_frame <= #`FF_DELAY pci_frame_reg_in ;
        read_completed_reg <= #`FF_DELAY read_completed_in ;
    end
end
 
// Address phase is when previous frame was 1 and this frame is 0 and frame isn't generated from pci master (in WBU)
wire    addr_phase = (previous_frame && ~pci_frame_reg_in && ~wbu_frame_en_in) ;
 
`ifdef      HOST
    `ifdef  NO_CNF_IMAGE
            // Wire tells when there is configuration (read or write) command with IDSEL signal active
            wire    config_access = 1'b0 ;
            // Write and read progresses are used for determining next state
            wire    write_progress  =   ( (read_completed_in && ~pciw_fifo_full_in && ~wbu_del_read_comp_pending_in) ||
                                          (~read_processing_in && ~pciw_fifo_full_in && ~wbu_del_read_comp_pending_in) ) ;
            wire    read_progress   =   ( (read_completed_in && wbw_fifo_empty_in) ) ;
    `else
            // Wire tells when there is configuration (read or write) command with IDSEL signal active
            wire    config_access = (pci_idsel_reg_in && pci_cbe_reg_in[3]) && (~pci_cbe_reg_in[2] && pci_cbe_reg_in[1]) &&     // idsel asserted with correct bus command(101x)
                                    (pci_ad_reg_in[1:0] == 2'b00) ;        // has to be type 0 configuration cycle
 
            // Write and read progresses are used for determining next state
            wire    write_progress  =   ( (norm_access_to_config_in) ||
                                                                  (read_completed_in && ~pciw_fifo_full_in && ~wbu_del_read_comp_pending_in) ||
                                          (~read_processing_in && ~pciw_fifo_full_in && ~wbu_del_read_comp_pending_in) ) ;
            wire    read_progress   =   ( (~read_completed_in && norm_access_to_config_in) ||
                                          (read_completed_in && wbw_fifo_empty_in) ) ;
    `endif
`else
            // Wire tells when there is configuration (read or write) command with IDSEL signal active
            wire    config_access = (pci_idsel_reg_in && pci_cbe_reg_in[3]) && (~pci_cbe_reg_in[2] && pci_cbe_reg_in[1]) &&     // idsel asserted with correct bus command(101x)
                                    (pci_ad_reg_in[1:0] == 2'b00) ;        // has to be type 0 configuration cycle
 
            // Write and read progresses are used for determining next state
            wire    write_progress  =   ( (norm_access_to_config_in) ||
                                                                  (read_completed_in && ~pciw_fifo_full_in && ~wbu_del_read_comp_pending_in) ||
                                          (~read_processing_in && ~pciw_fifo_full_in && ~wbu_del_read_comp_pending_in) ) ;
            wire    read_progress   =   ( (~read_completed_in && norm_access_to_config_in) ||
                                          (read_completed_in && wbw_fifo_empty_in) ) ;
`endif
 
// Signal for loading data to medium register from pcir fifo when read completed from WB side!
wire    prepare_rd_fifo_data = (read_completed_in && ~read_completed_reg) ;
 
// Write allowed to PCIW_FIFO
wire    write_to_fifo   =   ((read_completed_in && ~pciw_fifo_full_in && ~wbu_del_read_comp_pending_in) ||
                                                         (~read_processing_in && ~pciw_fifo_full_in && ~wbu_del_read_comp_pending_in)) ;
// Read allowed from PCIR_FIFO
wire    read_from_fifo  =   (read_completed_in && wbw_fifo_empty_in) ;
`ifdef      HOST
    `ifdef  NO_CNF_IMAGE
            // Read request is allowed to be proceed regarding the WB side
            wire    read_request    =   (~read_completed_in && ~read_processing_in) ;
    `else
            // Read request is allowed to be proceed regarding the WB side
            wire    read_request    =   (~read_completed_in && ~read_processing_in && ~norm_access_to_config_in) ;
    `endif
`else
            // Read request is allowed to be proceed regarding the WB side
            wire    read_request    =   (~read_completed_in && ~read_processing_in && ~norm_access_to_config_in) ;
`endif
 
// Critically calculated signals are latched in this clock period (address phase) to be used in the next clock period
reg             rw_cbe0 ;
reg             wr_progress ;
reg             rd_progress ;
reg             rd_from_fifo ;
reg             rd_request ;
reg             wr_to_fifo ;
reg             same_read_reg ;
 
always@(posedge clk_in or posedge reset_in)
begin
    if (reset_in)
    begin
        rw_cbe0                         <= #`FF_DELAY 1'b0 ;
        wr_progress                     <= #`FF_DELAY 1'b0 ;
        rd_progress                     <= #`FF_DELAY 1'b0 ;
        rd_from_fifo                    <= #`FF_DELAY 1'b0 ;
        rd_request                      <= #`FF_DELAY 1'b0 ;
        wr_to_fifo                      <= #`FF_DELAY 1'b0 ;
        same_read_reg                   <= #`FF_DELAY 1'b0 ;
    end
    else
    begin
        if (addr_phase)
        begin
            rw_cbe0                     <= #`FF_DELAY pci_cbe_reg_in[0] ;
            wr_progress                 <= #`FF_DELAY write_progress ;
            rd_progress                 <= #`FF_DELAY read_progress ;
            rd_from_fifo                <= #`FF_DELAY read_from_fifo ;
            rd_request                  <= #`FF_DELAY read_request ;
            wr_to_fifo                  <= #`FF_DELAY write_to_fifo ;
            same_read_reg               <= #`FF_DELAY same_read_in ;
        end
    end
end
 
`ifdef      HOST
    `ifdef  NO_CNF_IMAGE
            wire    norm_access_to_conf_reg     = 1'b0 ;
            wire    cnf_progress                = 1'b0 ;
    `else
            reg     norm_access_to_conf_reg ;
            reg     cnf_progress ;
            always@(posedge clk_in or posedge reset_in)
            begin
                if (reset_in)
                begin
                    norm_access_to_conf_reg     <= #`FF_DELAY 1'b0 ;
                    cnf_progress                <= #`FF_DELAY 1'b0 ;
                end
                else
                begin
                    if (addr_phase)
                    begin
                        norm_access_to_conf_reg <= #`FF_DELAY norm_access_to_config_in ;
                        cnf_progress            <= #`FF_DELAY config_access ;
                    end
                end
            end
    `endif
`else
            reg     norm_access_to_conf_reg ;
            reg     cnf_progress ;
            always@(posedge clk_in or posedge reset_in)
            begin
                if (reset_in)
                begin
                    norm_access_to_conf_reg     <= #`FF_DELAY 1'b0 ;
                    cnf_progress                <= #`FF_DELAY 1'b0 ;
                end
                else
                begin
                    if (addr_phase)
                    begin
                        norm_access_to_conf_reg <= #`FF_DELAY norm_access_to_config_in ;
                        cnf_progress            <= #`FF_DELAY config_access ;
                    end
                end
            end
`endif
 
// Signal used in S_WAIT state to determin next state
wire s_wait_progress =  (
                        (~cnf_progress && rw_cbe0 && wr_progress && ~target_abort_in) ||
                        (~cnf_progress && ~rw_cbe0 && same_read_reg && rd_progress && ~target_abort_in && ~pcir_fifo_data_err_in) ||
                        (~cnf_progress && ~rw_cbe0 && ~same_read_reg && norm_access_to_conf_reg && ~target_abort_in) ||
                        (cnf_progress && ~target_abort_in)
                        ) ;
 
// Signal used in S_TRANSFERE state to determin next state
wire s_tran_progress =  (
                        (rw_cbe0 && !disconect_wo_data) ||
                        (~rw_cbe0 && !disconect_wo_data && !target_abort_in && !pcir_fifo_data_err_in)
                        ) ;
 
// Clock enable for PCI state machine driven directly from critical inputs - FRAME and IRDY
wire            pcit_sm_clk_en ;
// FSM states signals indicating the current state
reg             state_idle ;
reg             state_wait ;
reg             sm_transfere ;
reg             backoff ;
reg             state_default ;
wire            state_backoff   = sm_transfere && backoff ;
wire            state_transfere = sm_transfere && !backoff ;
 
always@(posedge clk_in or posedge reset_in)
begin
    if ( reset_in )
        backoff <= #`FF_DELAY 1'b0 ;
    else if ( state_idle )
        backoff <= #`FF_DELAY 1'b0 ;
    else
        backoff <= #`FF_DELAY (state_wait && !s_wait_progress) ||
                              (sm_transfere && !s_tran_progress && !pci_frame_in && !pci_irdy_in) ||
                              backoff ;
end
assign config_disconnect = sm_transfere && (norm_access_to_conf_reg || cnf_progress) ;
 
// Clock enable module used for preserving the architecture because of minimum delay for critical inputs
PCI_TARGET32_CLK_EN         pci_target_clock_en
(
    .addr_phase             (addr_phase),
    .config_access          (config_access),
    .addr_claim_in          (addr_claim_in),
    .pci_frame_in           (pci_frame_in),
    .state_wait             (state_wait),
    .state_transfere        (sm_transfere),
    .state_default          (state_default),
    .clk_enable             (pcit_sm_clk_en)
);
 
reg [(`P_FSM_BITS - 1):0]  c_state ; //current state register
reg [(`P_FSM_BITS - 1):0]  n_state ; //next state input to current state register
 
// state machine register control
always@(posedge clk_in or posedge reset_in)
begin
    if (reset_in) // reset state machine to S_IDLE state
        c_state <= #`FF_DELAY S_IDLE ;
    else
        if (pcit_sm_clk_en) // if conditions are true, then FSM goes to next state!
            c_state <= #`FF_DELAY n_state ;
end
 
// state machine logic
always@(c_state)
begin
    case (c_state)
    S_IDLE :
    begin
        state_idle      <= 1'b1 ;
        state_wait      <= 1'b0 ;
        sm_transfere <= 1'b0 ;
        state_default   <= 1'b0 ;
        n_state <= S_WAIT ;
    end
    S_WAIT :
    begin
        state_idle      <= 1'b0 ;
        state_wait      <= 1'b1 ;
        sm_transfere <= 1'b0 ;
        state_default   <= 1'b0 ;
        n_state <= S_TRANSFERE ;
    end
    S_TRANSFERE :
    begin
        state_idle      <= 1'b0 ;
        state_wait      <= 1'b0 ;
        sm_transfere <= 1'b1 ;
        state_default   <= 1'b0 ;
        n_state <= S_IDLE ;
    end
    default :
    begin
        state_idle      <= 1'b0 ;
        state_wait      <= 1'b0 ;
        sm_transfere <= 1'b0 ;
        state_default   <= 1'b1 ;
        n_state <= S_IDLE ;
    end
    endcase
end
 
        // if not retry and not target abort
        // NO CRITICAL SIGNALS
wire    trdy_w          =   (
        (state_wait && ~cnf_progress && rw_cbe0 && wr_progress && ~target_abort_in) ||
        (state_wait && ~cnf_progress && ~rw_cbe0 && same_read_reg && rd_progress && ~target_abort_in && !pcir_fifo_data_err_in) ||
        (state_wait && ~cnf_progress && ~rw_cbe0 && ~same_read_reg && norm_access_to_conf_reg && ~target_abort_in) ||
        (state_wait && cnf_progress && ~target_abort_in)
                            ) ;
        // if not disconnect without data and not target abort (only during reads)
        // MUST BE ANDED WITH CRITICAL ~FRAME
wire    trdy_w_frm      =   (
        (state_transfere && !cnf_progress && !norm_access_to_conf_reg && rw_cbe0 && !disconect_wo_data) ||
        (state_transfere && !cnf_progress && !norm_access_to_conf_reg && ~rw_cbe0 && !disconect_wo_data && ~pcir_fifo_data_err_in) ||
        (state_transfere && !cnf_progress && !norm_access_to_conf_reg && disconect_w_data && pci_irdy_reg_in && (rw_cbe0 || !pcir_fifo_data_err_in))
                            ) ;
        // if not disconnect without data and not target abort (only during reads)
        // MUST BE ANDED WITH CRITICAL ~FRAME AND IRDY
wire    trdy_w_frm_irdy =   ( ~bckp_trdy_in ) ;
// TRDY critical module used for preserving the architecture because of minimum delay for critical inputs
PCI_TARGET32_TRDY_CRIT      pci_target_trdy_critical
(
    .trdy_w                 (trdy_w),
    .trdy_w_frm             (trdy_w_frm),
    .trdy_w_frm_irdy        (trdy_w_frm_irdy),
    .pci_frame_in           (pci_frame_in),
    .pci_irdy_in            (pci_irdy_in),
    .pci_trdy_out           (pci_trdy_out)
);
 
        // if target abort or retry
        // NO CRITICAL SIGNALS
wire    stop_w          =   (
        (state_wait && target_abort_in) ||
        (state_wait && ~cnf_progress && rw_cbe0 && ~wr_progress) ||
        (state_wait && ~cnf_progress && ~rw_cbe0 && same_read_reg && ~rd_progress) ||
        (state_wait && ~cnf_progress && ~rw_cbe0 && same_read_reg && rd_progress && pcir_fifo_data_err_in) ||
        (state_wait && ~cnf_progress && ~rw_cbe0 && ~same_read_reg && ~norm_access_to_conf_reg)
                            ) ;
        // if asserted, wait for deactivating the frame
        // MUST BE ANDED WITH CRITICAL ~FRAME
wire    stop_w_frm      =   (
        (state_backoff && ~bckp_stop_in)
                            ) ;
        // if target abort or if disconnect without data (after data transfere)
        // MUST BE ANDED WITH CRITICAL ~FRAME AND ~IRDY
wire    stop_w_frm_irdy =   (
        (state_transfere && (disconect_wo_data)) ||
        (state_transfere && ~rw_cbe0 && pcir_fifo_data_err_in)
                            ) ;
// STOP critical module used for preserving the architecture because of minimum delay for critical inputs
PCI_TARGET32_STOP_CRIT      pci_target_stop_critical
(
    .stop_w                 (stop_w),
    .stop_w_frm             (stop_w_frm),
    .stop_w_frm_irdy        (stop_w_frm_irdy),
    .pci_frame_in           (pci_frame_in),
    .pci_irdy_in            (pci_irdy_in),
    .pci_stop_out           (pci_stop_out)
);
 
        // if OK to respond and not target abort
        // NO CRITICAL SIGNALS
wire    devs_w          =   (
        (addr_phase && config_access) ||
        (addr_phase && ~config_access && addr_claim_in) ||
        (state_wait && ~target_abort_in && !(~cnf_progress && ~rw_cbe0 && same_read_reg && rd_progress && pcir_fifo_data_err_in) )
                            ) ;
 
        // if not target abort (only during reads) or if asserted, wait for deactivating the frame
        // MUST BE ANDED WITH CRITICAL ~FRAME
wire    devs_w_frm      =   (
        (state_transfere && rw_cbe0) ||
        (state_transfere && ~rw_cbe0 && ~pcir_fifo_data_err_in) ||
        (state_backoff && ~bckp_devsel_in)
                            ) ;
        // if not target abort (only during reads)
        // MUST BE ANDED WITH CRITICAL ~FRAME AND IRDY
wire    devs_w_frm_irdy =   (
        (state_transfere && ~rw_cbe0 && pcir_fifo_data_err_in)
                            ) ;
// DEVSEL critical module used for preserving the architecture because of minimum delay for critical inputs
PCI_TARGET32_DEVS_CRIT      pci_target_devsel_critical
(
    .devs_w                 (devs_w),
    .devs_w_frm             (devs_w_frm),
    .devs_w_frm_irdy        (devs_w_frm_irdy),
    .pci_frame_in           (pci_frame_in),
    .pci_irdy_in            (pci_irdy_in),
    .pci_devsel_out         (pci_devsel_out)
);
 
// signal used in AD enable module with preserving the hierarchy because of minimum delay for critical inputs
assign  pci_ad_en_out =    (
        (addr_phase && config_access && ~pci_cbe_reg_in[0]) ||
        (addr_phase && ~config_access && addr_claim_in && ~pci_cbe_reg_in[0]) ||
        (state_wait && ~rw_cbe0) ||
        (state_transfere && ~rw_cbe0) ||
        (state_backoff && ~rw_cbe0 && ~pci_frame_reg_in)
                            ) ;
 
wire fast_back_to_back  =   (addr_phase && ~pci_irdy_reg_in) ;
 
        // if cycle will progress or will not be stopped
        // NO CRITICAL SIGNALS
wire    ctrl_en       =
        /*(~wbu_frame_en_in && fast_back_to_back) ||*/
        (addr_phase && config_access) ||
        (addr_phase && ~config_access && addr_claim_in) ||
        (state_wait) ||
        (state_transfere && ~(pci_frame_reg_in && ~pci_irdy_reg_in && (~pci_stop_reg_in || ~pci_trdy_reg_in))) ||
        (state_backoff && ~(pci_frame_reg_in && ~pci_irdy_reg_in && (~pci_stop_reg_in || ~pci_trdy_reg_in))) ;
 
assign pci_trdy_en_out   = ctrl_en ;
assign pci_stop_en_out   = ctrl_en ;
assign pci_devsel_en_out = ctrl_en ;
 
// target ready output signal delayed for one clock used in conjunction with irdy_reg to select which
//   data are registered in io mux module - from fifo or medoum register
reg             bckp_trdy_reg ;
// delayed indicators for states transfere and backoff
reg             state_transfere_reg ;
reg             state_backoff_reg ;
always@(posedge clk_in or posedge reset_in)
begin
    if (reset_in)
    begin
        bckp_trdy_reg <= #`FF_DELAY 1'b1 ;
        state_transfere_reg <= #`FF_DELAY 1'b0 ;
        state_backoff_reg <= #`FF_DELAY 1'b0 ;
    end
    else
    begin
        bckp_trdy_reg <= #`FF_DELAY bckp_trdy_in ;
        state_transfere_reg <= #`FF_DELAY state_transfere ;
        state_backoff_reg <= #`FF_DELAY state_backoff ;
    end
end
 
// Read control signals assignments
assign
    fetch_pcir_fifo_out =   (
        (prepare_rd_fifo_data) ||
        (state_wait && ~cnf_progress && ~rw_cbe0 && same_read_reg && rd_from_fifo && ~target_abort_in) ||
        (bckp_trdy_en_in && ~pci_trdy_reg_in && ~cnf_progress && ~rw_cbe0 && same_read_reg && rd_from_fifo && ~pci_irdy_reg_in)
                            ) ;
 
assign  ad_load_out         =   (state_wait) ;
 
assign  ad_load_on_transfer_out = (bckp_trdy_en_in && ~rw_cbe0) ;
 
assign  load_medium_reg_out =   (
        (prepare_rd_fifo_data) ||
        (state_wait && ~rw_cbe0 && ~cnf_progress && same_read_reg && rd_from_fifo && ~target_abort_in) ||
        (~pci_irdy_reg_in && ~rw_cbe0 && ~cnf_progress && same_read_reg && rd_from_fifo && ~pci_trdy_reg_in && bckp_trdy_en_in)
                                ) ;
 
assign  sel_fifo_mreg_out = (~pci_irdy_reg_in && ~bckp_trdy_reg) ;
 
`ifdef      HOST
    `ifdef  NO_CNF_IMAGE
            assign  sel_conf_fifo_out = 1'b0 ;
    `else
            assign  sel_conf_fifo_out = (cnf_progress || norm_access_to_conf_reg) ;
    `endif
`else
            assign  sel_conf_fifo_out = (cnf_progress || norm_access_to_conf_reg) ;
`endif
 
// NOT USED NOW, SINCE READ IS ASYNCHRONOUS
//assign    fetch_conf_out = ((cnf_progress || norm_access_to_conf_reg) && ~rw_cbe0 && ~bckp_devsel_in) ;
assign  fetch_conf_out = 1'b0 ;
 
// Write control signals assignments
assign
    load_to_pciw_fifo_out = (
        (state_wait && (~cnf_progress && ~norm_access_to_conf_reg) && rw_cbe0 && wr_to_fifo && ~target_abort_in) ||
        (state_transfere_reg && ~state_backoff && rw_cbe0 && wr_to_fifo /*&& ~disconect_wo_data_reg*/ && ~pci_irdy_reg_in && ~bckp_trdy_reg && (~cnf_progress && ~norm_access_to_conf_reg)) ||
        ((state_backoff || state_backoff_reg) && rw_cbe0 && wr_to_fifo && ~pci_irdy_reg_in && ~bckp_trdy_reg && (~cnf_progress && ~norm_access_to_conf_reg))
                            ) ;
 
`ifdef      HOST
    `ifdef  NO_CNF_IMAGE
            assign  load_to_conf_out =  1'b0 ;
    `else
            assign  load_to_conf_out =  (
            (state_transfere_reg && cnf_progress && rw_cbe0 && ~pci_irdy_reg_in && ~bckp_trdy_reg) ||
            (state_transfere_reg && norm_access_to_conf_reg && rw_cbe0 && ~pci_irdy_reg_in && ~bckp_trdy_reg)
                                        ) ;
    `endif
`else
            assign  load_to_conf_out =  (
            (state_transfere_reg && cnf_progress && rw_cbe0 && ~pci_irdy_reg_in && ~bckp_trdy_reg) ||
            (state_transfere_reg && norm_access_to_conf_reg && rw_cbe0 && ~pci_irdy_reg_in && ~bckp_trdy_reg)
                                        ) ;
`endif
 
// General control sigal assignments
assign  addr_phase_out = addr_phase ;
assign  last_reg_out = (pci_frame_reg_in && ~pci_irdy_reg_in) ;
assign  frame_reg_out = pci_frame_reg_in ;
assign  bckp_devsel_out = bckp_devsel_in ;
assign  bckp_trdy_out   = bckp_trdy_in ;
assign  bckp_stop_out   = bckp_stop_in ;
assign  target_abort_set_out = (bckp_devsel_in && bckp_trdy_in && ~bckp_stop_in && bckp_trdy_en_in) ;
// request signal for delayed sinc. module
reg master_will_request_read ;
always@(posedge clk_in or posedge reset_in)
begin
    if ( reset_in )
        master_will_request_read <= #`FF_DELAY 1'b0 ;
    else
        master_will_request_read <= #`FF_DELAY ((state_wait && ~target_abort_in) || (state_backoff && ~target_abort_set_out)) && ~cnf_progress && ~norm_access_to_conf_reg && ~rw_cbe0 && rd_request ;
end
// MORE OPTIMIZED READS, but not easy to control in a testbench!
//assign  req_out = master_will_request_read ; 
assign req_out = master_will_request_read && !pci_irdy_reg_in && !read_processing_in ;
 
// ready tells when address or data are written into fifo - RDY ? DATA : ADDRESS
assign  rdy_out = ~bckp_trdy_reg ;
 
// data and address outputs assignments!
assign  pci_ad_out = data_in ;
 
assign  data_out = pci_ad_reg_in ;
assign  be_out = pci_cbe_reg_in ;
assign  address_out = pci_ad_reg_in ;
assign  bc_out = pci_cbe_reg_in ;
assign  bc0_out = rw_cbe0 ;
 
 
endmodule

Line No.	Rev	Author	Line
1	2	mihad	`//////////////////////////////////////////////////////////////////////`
2			`//// ////`
3			`//// File name: pci_target32_sm.v ////`
4			`//// ////`
5			`//// This file is part of the "PCI bridge" project ////`
6			`//// http://www.opencores.org/cores/pci/ ////`
7			`//// ////`
8			`//// Author(s): ////`
9			`//// - Tadej Markovic, tadej@opencores.org ////`
10			`//// ////`
11			`//// All additional information is avaliable in the README.txt ////`
12			`//// file. ////`
13			`//// ////`
14			`//// ////`
15			`//////////////////////////////////////////////////////////////////////`
16			`//// ////`
17			`//// Copyright (C) 2000 Tadej Markovic, tadej@opencores.org ////`
18			`//// ////`
19			`//// This source file may be used and distributed without ////`
20			`//// restriction provided that this copyright statement is not ////`
21			`//// removed from the file and that any derivative work contains ////`
22			`//// the original copyright notice and the associated disclaimer. ////`
23			`//// ////`
24			`//// This source file is free software; you can redistribute it ////`
25			`//// and/or modify it under the terms of the GNU Lesser General ////`
26			`//// Public License as published by the Free Software Foundation; ////`
27			`//// either version 2.1 of the License, or (at your option) any ////`
28			`//// later version. ////`
29			`//// ////`
30			`//// This source is distributed in the hope that it will be ////`
31			`//// useful, but WITHOUT ANY WARRANTY; without even the implied ////`
32			`//// warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR ////`
33			`//// PURPOSE. See the GNU Lesser General Public License for more ////`
34			`//// details. ////`
35			`//// ////`
36			`//// You should have received a copy of the GNU Lesser General ////`
37			`//// Public License along with this source; if not, download it ////`
38			`//// from http://www.opencores.org/lgpl.shtml ////`
39			`//// ////`
40			`//////////////////////////////////////////////////////////////////////`
41			`//`
42			`// CVS Revision History`
43			`//`
44			`// $Log: not supported by cvs2svn $`
45	51	mihad	`// Revision 1.4 2002/02/19 16:32:37 mihad`
46			`// Modified testbench and fixed some bugs`
47			`//`
48	26	mihad	`// Revision 1.3 2002/02/01 15:25:12 mihad`
49			`// Repaired a few bugs, updated specification, added test bench files and design document`
50			`//`
51	21	mihad	`// Revision 1.2 2001/10/05 08:14:30 mihad`
52			`// Updated all files with inclusion of timescale file for simulation purposes.`
53			`//`
54	6	mihad	`// Revision 1.1.1.1 2001/10/02 15:33:47 mihad`
55			`// New project directory structure`
56	2	mihad	`//`
57	6	mihad	`//`
58	2	mihad
59	21	mihad	`define P_FSM_BITS 2 // number of bits needed for FSM states
60	2	mihad
61	21	mihad	`include "pci_constants.v"
62	2	mihad
63	21	mihad	`// synopsys translate_off`
64	6	mihad	`include "timescale.v"
65	21	mihad	`// synopsys translate_on`
66	2	mihad
67			`module PCI_TARGET32_SM`
68			`(`
69			`// system inputs`
70			`clk_in,`
71			`reset_in,`
72			`// master inputs`
73			`pci_frame_in,`
74			`pci_irdy_in,`
75			`pci_idsel_in,`
76			`pci_frame_reg_in,`
77			`pci_irdy_reg_in,`
78			`pci_idsel_reg_in,`
79			`// target response outputs`
80			`pci_trdy_out,`
81			`pci_stop_out,`
82			`pci_devsel_out,`
83			`pci_trdy_en_out,`
84			`pci_stop_en_out,`
85			`pci_devsel_en_out,`
86	21	mihad	`ad_load_out,`
87			`ad_load_on_transfer_out,`
88	2	mihad	`// address, data, bus command, byte enable in/outs`
89			`pci_ad_reg_in,`
90			`pci_ad_out,`
91			`pci_ad_en_out,`
92			`pci_cbe_reg_in,`
93			`bckp_trdy_en_in,`
94			`bckp_devsel_in,`
95			`bckp_trdy_in,`
96			`bckp_stop_in,`
97	21	mihad	`pci_trdy_reg_in,`
98			`pci_stop_reg_in,`
99	2	mihad
100			`// backend side of state machine with control signals to pci_io_mux ...`
101			`address_out,`
102			`addr_claim_in,`
103			`bc_out,`
104			`bc0_out,`
105			`data_out,`
106			`data_in,`
107			`be_out,`
108			`req_out,`
109			`rdy_out,`
110			`addr_phase_out,`
111	21	mihad	`bckp_devsel_out,`
112	2	mihad	`bckp_trdy_out,`
113	21	mihad	`bckp_stop_out,`
114	2	mihad	`last_reg_out,`
115			`frame_reg_out,`
116	21	mihad	`fetch_pcir_fifo_out,`
117			`load_medium_reg_out,`
118			`sel_fifo_mreg_out,`
119			`sel_conf_fifo_out,`
120			`fetch_conf_out,`
121			`load_to_pciw_fifo_out,`
122	2	mihad	`load_to_conf_out,`
123	21	mihad	`same_read_in,`
124			`norm_access_to_config_in,`
125			`read_completed_in,`
126			`read_processing_in,`
127			`target_abort_in,`
128			`disconect_wo_data_in,`
129			`disconect_w_data_in,`
130			`target_abort_set_out,`
131			`pciw_fifo_full_in,`
132			`pcir_fifo_data_err_in,`
133			`wbw_fifo_empty_in,`
134			`wbu_del_read_comp_pending_in,`
135			`wbu_frame_en_in`
136	2	mihad
137			`) ;`
138
139			`/*----------------------------------------------------------------------------------------------------------------------`
140			`Various parameters needed for state machine and other stuff`
141			`----------------------------------------------------------------------------------------------------------------------*/`
142	21	mihad	parameter S_IDLE = `P_FSM_BITS'h0 ;
143			parameter S_WAIT = `P_FSM_BITS'h1 ;
144			parameter S_TRANSFERE = `P_FSM_BITS'h2 ;
145	2	mihad
146
147			`/*==================================================================================================================`
148			`System inputs.`
149			`==================================================================================================================*/`
150			`// PCI side clock and reset`
151			`input clk_in,`
152			`reset_in ;`
153
154
155			`/*==================================================================================================================`
156			`PCI interface signals - bidirectional signals are divided to inputs and outputs in I/O cells instantiation`
157			`module. Enables are separate signals.`
158			`==================================================================================================================*/`
159			`// master inputs`
160			`input pci_frame_in,`
161	21	mihad	`pci_irdy_in,`
162			`pci_idsel_in ;`
163	2	mihad	`input pci_frame_reg_in,`
164	21	mihad	`pci_irdy_reg_in,`
165			`pci_idsel_reg_in ;`
166
167	2	mihad	`// target response outputs`
168			`output pci_trdy_out,`
169			`pci_stop_out,`
170			`pci_devsel_out ;`
171			`output pci_trdy_en_out,`
172	21	mihad	`pci_stop_en_out,`
173			`pci_devsel_en_out ;`
174			`output ad_load_out ;`
175			`output ad_load_on_transfer_out ;`
176	2	mihad	`// address, data, bus command, byte enable in/outs`
177			`input [31:0] pci_ad_reg_in ;`
178			`output [31:0] pci_ad_out ;`
179			`output pci_ad_en_out ;`
180			`input [3:0] pci_cbe_reg_in ;`
181	21	mihad	`input bckp_trdy_en_in ;`
182			`input bckp_devsel_in ;`
183			`input bckp_trdy_in ;`
184			`input bckp_stop_in ;`
185			`input pci_trdy_reg_in ;`
186			`input pci_stop_reg_in ;`
187	2	mihad
188
189			`/*==================================================================================================================`
190			`Other side of PCI Target state machine`
191			`==================================================================================================================*/`
192			`// Data, byte enables, bus commands and address ports`
193	21	mihad	`output [31:0] address_out ; // current request address output - registered`
194			`input addr_claim_in ; // current request address claim input`
195			`output [3:0] bc_out ; // current request bus command output - registered`
196			`output bc0_out ; // current cycle RW signal output`
197			`input [31:0] data_in ; // for read operations - current dataphase data input`
198			`output [31:0] data_out ; // for write operations - current request data output - registered`
199			`output [3:0] be_out ; // current dataphase byte enable outputs - registered`
200	2	mihad	`// Port connection control signals from PCI FSM`
201	21	mihad	`output req_out ; // Read is requested to WB master`
202			`output rdy_out ; // DATA / ADDRESS selection when read or write - registered`
203			`output addr_phase_out ; // Indicates address phase and also fast-back-to-back address phase - registered`
204			`output bckp_devsel_out ; // DEVSEL output (which is registered) equivalent`
205			`output bckp_trdy_out ; // TRDY output (which is registered) equivalent`
206			`output bckp_stop_out ; // STOP output (which is registered) equivalent`
207			`output last_reg_out ; // Indicates last data phase - registered`
208			`output frame_reg_out ; // FRAME output signal - registered`
209			`output fetch_pcir_fifo_out ;// Read enable for PCIR_FIFO when when read is finishen on WB side`
210			`output load_medium_reg_out ;// Load data from PCIR_FIFO to medium register (first data must be prepared on time)`
211			`output sel_fifo_mreg_out ; // Read data selection between PCIR_FIFO and medium register`
212			`output sel_conf_fifo_out ; // Read data selection between Configuration registers and "FIFO"`
213			`output fetch_conf_out ; // Read enable for configuration space registers`
214			`output load_to_pciw_fifo_out ;// Write enable to PCIW_FIFO`
215			`output load_to_conf_out ; // Write enable to Configuration space registers`
216	2	mihad
217
218			`/*==================================================================================================================`
219			`Status`
220			`==================================================================================================================*/`
221	21	mihad	`input same_read_in ; // Indicates the same read request (important when read is finished on WB side)`
222			`input norm_access_to_config_in ; // Indicates the access to Configuration space with MEMORY commands`
223			`input read_completed_in ; // Indicates that read request is completed on WB side`
224			`input read_processing_in ; // Indicates that read request is processing on WB side`
225			`input target_abort_in ; // Indicates target abort termination`
226			`input disconect_wo_data_in ; // Indicates disconnect without data termination`
227			`input disconect_w_data_in ; // Indicates disconnect with data termination`
228			`input pciw_fifo_full_in ; // Indicates that write PCIW_FIFO is full`
229			`input pcir_fifo_data_err_in ; // Indicates data error on current data read from PCIR_FIFO`
230			`input wbw_fifo_empty_in ; // Indicates that WB SLAVE UNIT has no data to be written to PCI bus`
231			`input wbu_del_read_comp_pending_in ; // Indicates that WB S�AVE UNIT has a delayed read pending`
232			`input wbu_frame_en_in ; // Indicates that WB SLAVE UNIT is accessing the PCI bus (important if`
233			`// address on PCI bus is also claimed by decoder in this PCI TARGET UNIT`
234			`output target_abort_set_out ; // Signal used to be set in configuration space registers`
235	2	mihad
236			`/*==================================================================================================================`
237			`END of input / output PORT DEFINITONS !!!`
238			`==================================================================================================================*/`
239
240			`// Delayed frame signal for determining the address phase`
241	21	mihad	`reg previous_frame ;`
242	2	mihad	`// Delayed read completed signal for preparing the data from pcir fifo`
243	21	mihad	`reg read_completed_reg ;`
244			`// Delayed disconnect with/without data for stop loading data to PCIW_FIFO`
245			`//reg disconect_wo_data_reg ;`
246	2	mihad
247	21	mihad	`wire config_disconnect ;`
248			`wire disconect_wo_data = disconect_wo_data_in \|\| config_disconnect ;`
249			`wire disconect_w_data = disconect_w_data_in ;`
250	2	mihad	`// Delayed frame signal for determining the address phase!`
251			`always@(posedge clk_in or posedge reset_in)`
252			`begin`
253	21	mihad	`if (reset_in)`
254			`begin`
255			previous_frame <= #`FF_DELAY 1'b1 ;
256			read_completed_reg <= #`FF_DELAY 1'b0 ;
257			`end`
258	2	mihad	`else`
259	21	mihad	`begin`
260			previous_frame <= #`FF_DELAY pci_frame_reg_in ;
261			read_completed_reg <= #`FF_DELAY read_completed_in ;
262			`end`
263	2	mihad	`end`
264
265			`// Address phase is when previous frame was 1 and this frame is 0 and frame isn't generated from pci master (in WBU)`
266	21	mihad	`wire addr_phase = (previous_frame && ~pci_frame_reg_in && ~wbu_frame_en_in) ;`
267	2	mihad
268	21	mihad	`ifdef HOST
269			`ifdef NO_CNF_IMAGE
270			`// Wire tells when there is configuration (read or write) command with IDSEL signal active`
271			`wire config_access = 1'b0 ;`
272			`// Write and read progresses are used for determining next state`
273			`wire write_progress = ( (read_completed_in && ~pciw_fifo_full_in && ~wbu_del_read_comp_pending_in) \|\|`
274			`(~read_processing_in && ~pciw_fifo_full_in && ~wbu_del_read_comp_pending_in) ) ;`
275			`wire read_progress = ( (read_completed_in && wbw_fifo_empty_in) ) ;`
276			`else
277			`// Wire tells when there is configuration (read or write) command with IDSEL signal active`
278	51	mihad	`wire config_access = (pci_idsel_reg_in && pci_cbe_reg_in[3]) && (~pci_cbe_reg_in[2] && pci_cbe_reg_in[1]) && // idsel asserted with correct bus command(101x)`
279			`(pci_ad_reg_in[1:0] == 2'b00) ; // has to be type 0 configuration cycle`
280
281	21	mihad	`// Write and read progresses are used for determining next state`
282			`wire write_progress = ( (norm_access_to_config_in) \|\|`
283			`(read_completed_in && ~pciw_fifo_full_in && ~wbu_del_read_comp_pending_in) \|\|`
284			`(~read_processing_in && ~pciw_fifo_full_in && ~wbu_del_read_comp_pending_in) ) ;`
285			`wire read_progress = ( (~read_completed_in && norm_access_to_config_in) \|\|`
286			`(read_completed_in && wbw_fifo_empty_in) ) ;`
287			`endif
288			`else
289			`// Wire tells when there is configuration (read or write) command with IDSEL signal active`
290	51	mihad	`wire config_access = (pci_idsel_reg_in && pci_cbe_reg_in[3]) && (~pci_cbe_reg_in[2] && pci_cbe_reg_in[1]) && // idsel asserted with correct bus command(101x)`
291			`(pci_ad_reg_in[1:0] == 2'b00) ; // has to be type 0 configuration cycle`
292
293	21	mihad	`// Write and read progresses are used for determining next state`
294			`wire write_progress = ( (norm_access_to_config_in) \|\|`
295			`(read_completed_in && ~pciw_fifo_full_in && ~wbu_del_read_comp_pending_in) \|\|`
296			`(~read_processing_in && ~pciw_fifo_full_in && ~wbu_del_read_comp_pending_in) ) ;`
297			`wire read_progress = ( (~read_completed_in && norm_access_to_config_in) \|\|`
298			`(read_completed_in && wbw_fifo_empty_in) ) ;`
299			`endif
300	2	mihad
301	21	mihad	`// Signal for loading data to medium register from pcir fifo when read completed from WB side!`
302			`wire prepare_rd_fifo_data = (read_completed_in && ~read_completed_reg) ;`
303	2	mihad
304			`// Write allowed to PCIW_FIFO`
305	21	mihad	`wire write_to_fifo = ((read_completed_in && ~pciw_fifo_full_in && ~wbu_del_read_comp_pending_in) \|\|`
306			`(~read_processing_in && ~pciw_fifo_full_in && ~wbu_del_read_comp_pending_in)) ;`
307	2	mihad	`// Read allowed from PCIR_FIFO`
308	21	mihad	`wire read_from_fifo = (read_completed_in && wbw_fifo_empty_in) ;`
309			`ifdef HOST
310			`ifdef NO_CNF_IMAGE
311			`// Read request is allowed to be proceed regarding the WB side`
312			`wire read_request = (~read_completed_in && ~read_processing_in) ;`
313			`else
314			`// Read request is allowed to be proceed regarding the WB side`
315			`wire read_request = (~read_completed_in && ~read_processing_in && ~norm_access_to_config_in) ;`
316			`endif
317			`else
318			`// Read request is allowed to be proceed regarding the WB side`
319			`wire read_request = (~read_completed_in && ~read_processing_in && ~norm_access_to_config_in) ;`
320			`endif
321	2	mihad
322			`// Critically calculated signals are latched in this clock period (address phase) to be used in the next clock period`
323	21	mihad	`reg rw_cbe0 ;`
324			`reg wr_progress ;`
325			`reg rd_progress ;`
326			`reg rd_from_fifo ;`
327			`reg rd_request ;`
328			`reg wr_to_fifo ;`
329			`reg same_read_reg ;`
330	2	mihad
331			`always@(posedge clk_in or posedge reset_in)`
332			`begin`
333	21	mihad	`if (reset_in)`
334			`begin`
335			rw_cbe0 <= #`FF_DELAY 1'b0 ;
336			wr_progress <= #`FF_DELAY 1'b0 ;
337			rd_progress <= #`FF_DELAY 1'b0 ;
338			rd_from_fifo <= #`FF_DELAY 1'b0 ;
339			rd_request <= #`FF_DELAY 1'b0 ;
340			wr_to_fifo <= #`FF_DELAY 1'b0 ;
341			same_read_reg <= #`FF_DELAY 1'b0 ;
342			`end`
343			`else`
344			`begin`
345			`if (addr_phase)`
346			`begin`
347			rw_cbe0 <= #`FF_DELAY pci_cbe_reg_in[0] ;
348			wr_progress <= #`FF_DELAY write_progress ;
349			rd_progress <= #`FF_DELAY read_progress ;
350			rd_from_fifo <= #`FF_DELAY read_from_fifo ;
351			rd_request <= #`FF_DELAY read_request ;
352			wr_to_fifo <= #`FF_DELAY write_to_fifo ;
353			same_read_reg <= #`FF_DELAY same_read_in ;
354			`end`
355			`end`
356	2	mihad	`end`
357
358	21	mihad	`ifdef HOST
359			`ifdef NO_CNF_IMAGE
360			`wire norm_access_to_conf_reg = 1'b0 ;`
361			`wire cnf_progress = 1'b0 ;`
362			`else
363			`reg norm_access_to_conf_reg ;`
364			`reg cnf_progress ;`
365			`always@(posedge clk_in or posedge reset_in)`
366			`begin`
367			`if (reset_in)`
368			`begin`
369			norm_access_to_conf_reg <= #`FF_DELAY 1'b0 ;
370			cnf_progress <= #`FF_DELAY 1'b0 ;
371			`end`
372			`else`
373			`begin`
374			`if (addr_phase)`
375			`begin`
376			norm_access_to_conf_reg <= #`FF_DELAY norm_access_to_config_in ;
377			cnf_progress <= #`FF_DELAY config_access ;
378			`end`
379			`end`
380			`end`
381			`endif
382			`else
383			`reg norm_access_to_conf_reg ;`
384			`reg cnf_progress ;`
385			`always@(posedge clk_in or posedge reset_in)`
386			`begin`
387			`if (reset_in)`
388			`begin`
389			norm_access_to_conf_reg <= #`FF_DELAY 1'b0 ;
390			cnf_progress <= #`FF_DELAY 1'b0 ;
391			`end`
392			`else`
393			`begin`
394			`if (addr_phase)`
395			`begin`
396			norm_access_to_conf_reg <= #`FF_DELAY norm_access_to_config_in ;
397			cnf_progress <= #`FF_DELAY config_access ;
398			`end`
399			`end`
400			`end`
401			`endif
402
403	2	mihad	`// Signal used in S_WAIT state to determin next state`
404	21	mihad	`wire s_wait_progress = (`
405			`(~cnf_progress && rw_cbe0 && wr_progress && ~target_abort_in) \|\|`
406			`(~cnf_progress && ~rw_cbe0 && same_read_reg && rd_progress && ~target_abort_in && ~pcir_fifo_data_err_in) \|\|`
407			`(~cnf_progress && ~rw_cbe0 && ~same_read_reg && norm_access_to_conf_reg && ~target_abort_in) \|\|`
408			`(cnf_progress && ~target_abort_in)`
409			`) ;`
410	2	mihad
411			`// Signal used in S_TRANSFERE state to determin next state`
412	21	mihad	`wire s_tran_progress = (`
413			`(rw_cbe0 && !disconect_wo_data) \|\|`
414			`(~rw_cbe0 && !disconect_wo_data && !target_abort_in && !pcir_fifo_data_err_in)`
415			`) ;`
416
417	2	mihad	`// Clock enable for PCI state machine driven directly from critical inputs - FRAME and IRDY`
418	21	mihad	`wire pcit_sm_clk_en ;`
419	2	mihad	`// FSM states signals indicating the current state`
420	21	mihad	`reg state_idle ;`
421			`reg state_wait ;`
422			`reg sm_transfere ;`
423			`reg backoff ;`
424			`reg state_default ;`
425			`wire state_backoff = sm_transfere && backoff ;`
426			`wire state_transfere = sm_transfere && !backoff ;`
427
428			`always@(posedge clk_in or posedge reset_in)`
429			`begin`
430			`if ( reset_in )`
431			backoff <= #`FF_DELAY 1'b0 ;
432			`else if ( state_idle )`
433			backoff <= #`FF_DELAY 1'b0 ;
434			`else`
435			backoff <= #`FF_DELAY (state_wait && !s_wait_progress) \|\|
436			`(sm_transfere && !s_tran_progress && !pci_frame_in && !pci_irdy_in) \|\|`
437			`backoff ;`
438			`end`
439			`assign config_disconnect = sm_transfere && (norm_access_to_conf_reg \|\| cnf_progress) ;`
440
441	2	mihad	`// Clock enable module used for preserving the architecture because of minimum delay for critical inputs`
442	21	mihad	`PCI_TARGET32_CLK_EN pci_target_clock_en`
443	2	mihad	`(`
444	21	mihad	`.addr_phase (addr_phase),`
445			`.config_access (config_access),`
446			`.addr_claim_in (addr_claim_in),`
447			`.pci_frame_in (pci_frame_in),`
448			`.state_wait (state_wait),`
449			`.state_transfere (sm_transfere),`
450			`.state_default (state_default),`
451			`.clk_enable (pcit_sm_clk_en)`
452	2	mihad	`);`
453
454	21	mihad	reg [(`P_FSM_BITS - 1):0] c_state ; //current state register
455			reg [(`P_FSM_BITS - 1):0] n_state ; //next state input to current state register
456	2	mihad
457			`// state machine register control`
458			`always@(posedge clk_in or posedge reset_in)`
459			`begin`
460			`if (reset_in) // reset state machine to S_IDLE state`
461			c_state <= #`FF_DELAY S_IDLE ;
462			`else`
463	21	mihad	`if (pcit_sm_clk_en) // if conditions are true, then FSM goes to next state!`
464			c_state <= #`FF_DELAY n_state ;
465			`end`
466	2	mihad
467			`// state machine logic`
468	21	mihad	`always@(c_state)`
469	2	mihad	`begin`
470	21	mihad	`case (c_state)`
471			`S_IDLE :`
472			`begin`
473			`state_idle <= 1'b1 ;`
474			`state_wait <= 1'b0 ;`
475			`sm_transfere <= 1'b0 ;`
476			`state_default <= 1'b0 ;`
477			`n_state <= S_WAIT ;`
478			`end`
479			`S_WAIT :`
480			`begin`
481			`state_idle <= 1'b0 ;`
482			`state_wait <= 1'b1 ;`
483			`sm_transfere <= 1'b0 ;`
484			`state_default <= 1'b0 ;`
485			`n_state <= S_TRANSFERE ;`
486			`end`
487			`S_TRANSFERE :`
488			`begin`
489			`state_idle <= 1'b0 ;`
490			`state_wait <= 1'b0 ;`
491			`sm_transfere <= 1'b1 ;`
492			`state_default <= 1'b0 ;`
493			`n_state <= S_IDLE ;`
494			`end`
495			`default :`
496			`begin`
497			`state_idle <= 1'b0 ;`
498			`state_wait <= 1'b0 ;`
499			`sm_transfere <= 1'b0 ;`
500			`state_default <= 1'b1 ;`

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[/] [pci/] [tags/] [rel_3/] [rtl/] [verilog/] [pci_target32_sm.v] - Blame information for rev 51