pci_wb_slave.v

这是用pci-wishbone核和16450串口核在xilinx的fpga上实现的串口程序

//////////////////////////////////////////////////////////////////////
////                                                              ////
////  File name "wb_slave.v"                                      ////
////                                                              ////
////  This file is part of the "PCI bridge" project               ////
////  http://www.opencores.org/cores/pci/                         ////
////                                                              ////
////  Author(s):                                                  ////
////      - Miha Dolenc ([e-mail])                     ////
////                                                              ////
////  All additional information is avaliable in the README       ////
////  file.                                                       ////
////                                                              ////
////                                                              ////
//////////////////////////////////////////////////////////////////////
////                                                              ////
//// Copyright (C) 2001 Miha Dolenc, [e-mail]          ////
////                                                              ////
//// 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: pci_wb_slave.v,v $
// Revision 1.5  2004/01/24 11:54:18  mihad
// Update! SPOCI Implemented!
//
// Revision 1.4  2003/12/19 11:11:30  mihad
// Compact PCI Hot Swap support added.
// New testcases added.
// Specification updated.
// Test application changed to support WB B3 cycles.
//
// Revision 1.3  2003/08/14 18:01:53  simons
// ifdefs moved to thier own lines, this confuses some of the tools.
//
// Revision 1.2  2003/08/03 18:05:06  mihad
// Added limited WISHBONE B3 support for WISHBONE Slave Unit.
// Doesn't support full speed bursts yet.
//
// Revision 1.1  2003/01/27 16:49:31  mihad
// Changed module and file names. Updated scripts accordingly. FIFO synchronizations changed.
//
// Revision 1.4  2002/08/19 16:54:25  mihad
// Got rid of undef directives
//
// Revision 1.3  2002/02/01 15:25:13  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
//
//

`include "bus_commands.v"
`include "pci_constants.v"

// synopsys translate_off
`include "timescale.v"
// synopsys translate_on

module pci_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,
                    init_complete_in,
                    cache_line_size_not_zero,
                    sample_address_out,
                    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 that locks out all accesses, except delayed completions or configuration accesses.
( when master operation is disabled via master enable bit in configuration spacei )
init_complete_in: while initialization sequence is in progress, the state machine
remains in the idle state - it does not respond to accesses.
---------------------------------------------------------------------------------------------------------------------*/
input           wbs_lock_in ;
input           init_complete_in ;

// cache line size register must hold appropriate value to enable read bursts and special commands on PCI bus!
input           cache_line_size_not_zero ;

// state machine signals to wb_addr_mux when to sample wb address input
output          sample_address_out ;
reg             sample_address_out ;

/*----------------------------------------------------------------------------------------------------------------------
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