oh/elink/hdl/erx_cfg.v

/*
 ########################################################################
 ELINK CONFIGURATION REGISTER FILE
 ########################################################################
 
 */
`include "elink_regmap.v"

module erx_cfg (/*AUTOARG*/
   // Outputs
   mi_dout, rx_enable, mmu_enable, remap_mode, remap_base,
   remap_pattern, remap_sel, timer_cfg,
   // Inputs
   reset, clk, mi_en, mi_we, mi_addr, mi_din, gpio_datain, rx_status
   );

   /******************************/
   /*Compile Time Parameters     */
   /******************************/
   parameter RFAW            = 6;         // 32 registers for now
   parameter GROUP           = 4'h0;
   
   /******************************/
   /*HARDWARE RESET (EXTERNAL)   */
   /******************************/
   input 	reset;       // ecfg registers reset only by "hard reset"
   input 	clk;
   /*****************************/
   /*SIMPLE MEMORY INTERFACE    */
   /*****************************/    
   input 	 mi_en;         
   input 	 mi_we;            // single we, must write 32 bit words
   input [14:0]  mi_addr;          // complete physical address (no shifting!)
   input [31:0]  mi_din;
   output [31:0] mi_dout;   
   
   /*****************************/
   /*CONFIG SIGNALS             */
   /*****************************/
   //rx
   output 	 rx_enable;      // enable signal for rx  
   output 	 mmu_enable;     // enables MMU on rx path (static)  
   input [8:0] 	 gpio_datain;    // frame and data inputs (static)        
   input [15:0]  rx_status;      // etx status signals
   output [1:0]  remap_mode;     // remap mode (static)       
   output [31:0] remap_base;     // base for dynamic remap (static) 
   output [11:0] remap_pattern;  // patter for static remap (static)
   output [11:0] remap_sel;      // selects for static remap (static)
   output [1:0]  timer_cfg;      // timeout config (00=off) (static)
   
   /*------------------------CODE BODY---------------------------------------*/
   
   //registers
   reg [31:0] 	ecfg_rx_reg;
   reg [31:0] 	ecfg_offset_reg;
   reg [8:0] 	ecfg_gpio_reg;
   reg [2:0] 	ecfg_rx_status_reg;
   reg [31:0] 	mi_dout;
   
   //wires
   wire 	ecfg_read;
   wire 	ecfg_write;
   wire 	ecfg_rx_write;
   wire  	ecfg_base_write;
   wire  	ecfg_remap_write;
   
   /*****************************/
   /*ADDRESS DECODE LOGIC       */
   /*****************************/

   //read/write decode
   assign ecfg_write  = mi_en &  mi_we;
   assign ecfg_read   = mi_en & ~mi_we;   

   //Config write enables
   assign ecfg_rx_write      = ecfg_write & (mi_addr[RFAW+1:2]==`ERX_CFG);
   assign ecfg_base_write    = ecfg_write & (mi_addr[RFAW+1:2]==`ERX_OFFSET);
   
   //###########################
   //# RXCFG
   //###########################
   always @ (posedge clk)
     if(reset)
       ecfg_rx_reg[31:0] <= 'b0;
     else if (ecfg_rx_write)
       ecfg_rx_reg[31:0] <= mi_din[31:0];

   assign rx_enable           = 1'b1;//is there any good reason turn RX off?
   assign mmu_enable          = ecfg_rx_reg[1];
   assign remap_mode[1:0]     = ecfg_rx_reg[3:2];
   assign remap_sel[11:0]     = ecfg_rx_reg[15:4];
   assign remap_pattern[11:0] = ecfg_rx_reg[27:16];
   assign timer_cfg[1:0]      = ecfg_rx_reg[29:28];
      
   //###########################
   //# DATAIN
   //###########################
   always @ (posedge clk)
     ecfg_gpio_reg[8:0] <= gpio_datain[8:0];
   
   //###########################1
   //# DEBUG
   //###########################   
   always @ (posedge clk)
     if(reset)
       ecfg_rx_status_reg[2:0] <= 'b0;   
     else
       ecfg_rx_status_reg[2:0] <= ecfg_rx_status_reg[2:0] | rx_status[2:0];

   //###########################1
   //# DYNAMIC REMAP BASE
   //###########################
   always @ (posedge clk)   
     if (ecfg_base_write)
       ecfg_offset_reg[31:0] <= mi_din[31:0];

   assign remap_base[31:0] = ecfg_offset_reg[31:0];
   
   //###############################
   //# DATA READBACK MUX
   //###############################

   //Pipelineing readback
   always @ (posedge clk)
     if(ecfg_read)
       case(mi_addr[RFAW+1:2])
         `ERX_CFG:     mi_dout[31:0] <= {ecfg_rx_reg[31:0]};
         `ERX_GPIO:    mi_dout[31:0] <= {23'b0, ecfg_gpio_reg[8:0]};
	 `ERX_STATUS:  mi_dout[31:0] <= {16'b0, rx_status[15:3],ecfg_rx_status_reg[2:0]};
	 `ERX_OFFSET:  mi_dout[31:0] <= {ecfg_offset_reg[31:0]};
         default:      mi_dout[31:0] <= 32'd0;
       endcase // case (mi_addr[RFAW+1:2])
     else
       mi_dout[31:0] <= 32'd0;
   
endmodule // ecfg_rx

/*
  Copyright (C) 2013 Adapteva, Inc.
  Contributed by Andreas Olofsson <andreas@adapteva.com>
 
   This program is free software: you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation, either version 3 of the License, or
  (at your option) any later version.This program is distributed in the hope 
  that it will be useful,but WITHOUT ANY WARRANTY; without even the implied 
  warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details. You should have received a copy 
  of the GNU General Public License along with this program (see the file 
  COPYING).  If not, see <http://www.gnu.org/licenses/>.
*/