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[/] [openrisc/] [trunk/] [orpsocv2/] [rtl/] [verilog/] [ethmac/] [eth_fifo.v] - Blame information for rev 791

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1 6 julius
//////////////////////////////////////////////////////////////////////
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////                                                              ////
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////  eth_fifo.v                                                  ////
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////                                                              ////
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////  This file is part of the Ethernet IP core project           ////
6 439 julius
////  http://www.opencores.org/project,ethmac                     ////
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////                                                              ////
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////  Author(s):                                                  ////
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////      - Igor Mohor (igorM@opencores.org)                      ////
10 439 julius
////      - Julius Baxter (julius@opencores.org)                  ////
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////                                                              ////
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////  All additional information is avaliable in the Readme.txt   ////
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////  file.                                                       ////
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////                                                              ////
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//////////////////////////////////////////////////////////////////////
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////                                                              ////
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//// Copyright (C) 2001 Authors                                   ////
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////                                                              ////
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//// This source file may be used and distributed without         ////
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//// restriction provided that this copyright statement is not    ////
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//// removed from the file and that any derivative work contains  ////
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//// the original copyright notice and the associated disclaimer. ////
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////                                                              ////
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//// This source file is free software; you can redistribute it   ////
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//// and/or modify it under the terms of the GNU Lesser General   ////
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//// Public License as published by the Free Software Foundation; ////
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//// either version 2.1 of the License, or (at your option) any   ////
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//// later version.                                               ////
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////                                                              ////
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//// This source is distributed in the hope that it will be       ////
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//// useful, but WITHOUT ANY WARRANTY; without even the implied   ////
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//// warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR      ////
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//// PURPOSE.  See the GNU Lesser General Public License for more ////
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//// details.                                                     ////
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////                                                              ////
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//// You should have received a copy of the GNU Lesser General    ////
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//// Public License along with this source; if not, download it   ////
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//// from http://www.opencores.org/lgpl.shtml                     ////
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////                                                              ////
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//////////////////////////////////////////////////////////////////////
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42 409 julius
`include "ethmac_defines.v"
43 6 julius
`include "timescale.v"
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45 439 julius
module eth_fifo (data_in, data_out, clk, reset, write, read, clear,
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                 almost_full, full, almost_empty, empty, cnt);
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48 530 julius
   parameter DATA_WIDTH    = 32;
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   parameter DEPTH         = 8;
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   parameter CNT_WIDTH     = 3;
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52 530 julius
   input                     clk;
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   input                     reset;
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   input                     write;
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   input                     read;
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   input                     clear;
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   input [DATA_WIDTH-1:0]    data_in;
58 6 julius
 
59 530 julius
   output [DATA_WIDTH-1:0]   data_out;
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   output                    almost_full;
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   output                    full;
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   output                    almost_empty;
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   output                    empty;
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   output [CNT_WIDTH-1:0]    cnt;
65 6 julius
 
66
 
67 530 julius
   reg [CNT_WIDTH-1:0]        read_pointer;
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   reg [CNT_WIDTH-1:0]        cnt;
69 403 julius
 
70 530 julius
   always @ (posedge clk or posedge reset)
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     begin
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        if(reset)
73
          cnt <= 0;
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        else
75
          if(clear)
76
            cnt <= { {(CNT_WIDTH-1){1'b0}}, read^write};
77
          else
78
            if(read ^ write)
79
              if(read)
80
                cnt <= cnt - 1;
81
              else
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                cnt <= cnt + 1;
83
     end
84 6 julius
 
85 530 julius
 
86
   assign empty = ~(|cnt);
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   assign almost_empty = cnt==1;
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   assign full  = {{32-CNT_WIDTH{1'b0}},cnt} == (DEPTH-1);
89
   assign almost_full  = {{32-CNT_WIDTH{1'b0}},cnt} == (DEPTH-2);
90
 
91 403 julius
 
92
`ifdef ETH_FIFO_GENERIC
93
 
94
   reg     [DATA_WIDTH-1:0]  fifo  [0:DEPTH-1] /*synthesis syn_ramstyle = "no_rw_check"*/ ;
95
 
96
 
97 439 julius
   // This should make the synthesis tool infer a RAM
98 530 julius
   reg [CNT_WIDTH-1:0]        waddr, raddr, raddr_reg;
99
   reg                       clear_reg; // Register the clear pulse
100 439 julius
 
101 530 julius
   reg                       fallthrough_read;
102
   reg [CNT_WIDTH-1:0]        fallthrough_read_addr;
103 439 julius
 
104 403 julius
 
105
   always @(posedge clk)
106
     if (reset)
107 439 julius
       fallthrough_read <= 0;
108
     else
109
       fallthrough_read <= empty & write;
110
 
111
   always @(posedge clk)
112
     if (empty & write)
113
       fallthrough_read_addr <= waddr;
114 530 julius
 
115 439 julius
   always @(posedge clk)
116
     if (reset)
117 403 julius
       waddr <= 0;
118
     else if (write)
119
       waddr <= waddr + 1;
120
 
121
   always @(posedge clk)
122
     if (reset)
123
       raddr <= 0;
124
     else if (clear)
125
       raddr <= waddr;
126 439 julius
     else if (read | clear_reg)
127 403 julius
       raddr <= raddr + 1;
128
 
129
   always @ (posedge clk)
130
     if (write & ~full)
131
       fifo[waddr] <=  data_in;
132
 
133
 
134
   always @(posedge clk)
135
     clear_reg <= clear;
136
 
137
   always @ (posedge clk)
138
     if (read | clear_reg)
139
       raddr_reg <= raddr;
140 439 julius
     else if (fallthrough_read) // To pulse RE for fall-through on Xilinx
141
       raddr_reg <= fallthrough_read_addr;
142 403 julius
 
143
   assign  data_out = fifo[raddr_reg];
144
 
145 530 julius
   always @ (posedge clk or posedge reset)
146
     begin
147
        if(reset)
148
          read_pointer <= 0;
149
        else
150
          if(clear)
151
            // Begin read pointer at 1
152
            read_pointer <= { {(CNT_WIDTH-1){1'b0}}, 1'b1};
153
          else
154
            if(read & ~empty)
155
              read_pointer <= read_pointer + 1'b1;
156
     end
157 403 julius
 
158
 
159 530 julius
`else // !`ifdef ETH_FIFO_GENERIC
160 485 julius
 
161 530 julius
   reg     [CNT_WIDTH-1:0]   write_pointer;
162 485 julius
 
163
 
164 530 julius
   always @ (posedge clk or posedge reset)
165
     begin
166
        if(reset)
167
          read_pointer <= 0;
168
        else
169
          if(clear)
170
            read_pointer <= { {(CNT_WIDTH-1){1'b0}}, read};
171
          else
172
            if(read & ~empty)
173
              read_pointer <= read_pointer + 1'b1;
174
     end
175 485 julius
 
176 530 julius
   always @ (posedge clk or posedge reset)
177
     begin
178
        if(reset)
179
          write_pointer <= 0;
180
        else
181
          if(clear)
182
            write_pointer <= { {(CNT_WIDTH-1){1'b0}}, write};
183
          else
184
            if(write & ~full)
185
              write_pointer <= write_pointer + 1'b1;
186
     end // always @ (posedge clk or posedge reset)
187 485 julius
 
188 530 julius
`endif // !`ifdef ETH_FIFO_GENERIC
189
 
190
 `ifdef ETH_FIFO_XILINX
191 403 julius
 
192 530 julius
   generate
193
      if (CNT_WIDTH==4)
194
        begin
195
           xilinx_dist_ram_16x32 fifo
196
             ( .data_out(data_out),
197
               .we(write & ~full),
198
               .data_in(data_in),
199
               .read_address( clear ? {CNT_WIDTH-1{1'b0}} : read_pointer[3:0]),
200
               .write_address(clear ? {CNT_WIDTH-1{1'b0}} : write_pointer[3:0]),
201
               .wclk(clk)
202
               );
203
        end // if (CNT_WIDTH==4)
204
      else if (CNT_WIDTH==6)
205
        begin
206 403 julius
 
207 530 julius
           wire  [DATA_WIDTH-1:0]  data_out0;
208
           wire [DATA_WIDTH-1:0]   data_out1;
209
           wire [DATA_WIDTH-1:0]   data_out2;
210
           wire [DATA_WIDTH-1:0]   data_out3;
211
 
212
           wire                    we_ram0,we_ram1,we_ram2,we_ram3;
213 6 julius
 
214 530 julius
           assign we_ram0 = (write_pointer[5:4]==2'b00);
215
           assign we_ram1 = (write_pointer[5:4]==2'b01);
216
           assign we_ram2 = (write_pointer[5:4]==2'b10);
217
           assign we_ram3 = (write_pointer[5:4]==2'b11);
218
 
219
           assign data_out = (read_pointer[5:4]==2'b11) ? data_out3 :
220
                             (read_pointer[5:4]==2'b10) ? data_out2 :
221
                             (read_pointer[5:4]==2'b01) ? data_out1 : data_out0;
222
 
223
           xilinx_dist_ram_16x32 fifo0
224
             ( .data_out(data_out0),
225
               .we(write & ~full & we_ram0),
226
               .data_in(data_in),
227
               .read_address( clear ? {CNT_WIDTH-1{1'b0}} : read_pointer[3:0]),
228
               .write_address(clear ? {CNT_WIDTH-1{1'b0}} : write_pointer[3:0]),
229
               .wclk(clk)
230
               );
231
 
232
           xilinx_dist_ram_16x32 fifo1
233
             ( .data_out(data_out1),
234
               .we(write & ~full & we_ram1),
235
               .data_in(data_in),
236
               .read_address( clear ? {CNT_WIDTH-1{1'b0}} : read_pointer[3:0]),
237
               .write_address(clear ? {CNT_WIDTH-1{1'b0}} : write_pointer[3:0]),
238
               .wclk(clk)
239
               );
240 6 julius
 
241 530 julius
           xilinx_dist_ram_16x32 fifo2
242
             ( .data_out(data_out2),
243
               .we(write & ~full & we_ram2),
244
               .data_in(data_in),
245
               .read_address( clear ? {CNT_WIDTH-1{1'b0}} : read_pointer[3:0]),
246
               .write_address(clear ? {CNT_WIDTH-1{1'b0}} : write_pointer[3:0]),
247
               .wclk(clk)
248
               );
249
 
250
           xilinx_dist_ram_16x32 fifo3
251
             ( .data_out(data_out3),
252
               .we(write & ~full & we_ram3),
253
               .data_in(data_in),
254
               .read_address( clear ? {CNT_WIDTH-1{1'b0}} : read_pointer[3:0]),
255
               .write_address(clear ? {CNT_WIDTH-1{1'b0}} : write_pointer[3:0]),
256
               .wclk(clk)
257
               );
258
        end // if (CNT_WIDTH==6)
259
 
260
   endgenerate
261
 `endif //  `ifdef ETH_FIFO_XILINX
262 485 julius
 
263 530 julius
   `ifdef ETH_FIFO_RAMB18
264 485 julius
 
265 530 julius
   wire [8:0]                       read_pointer_to_xilinx_ram;
266
   wire [8:0]                       read_pointer_preincremented;
267
   assign read_pointer_preincremented = read_pointer + 1;
268 485 julius
 
269 530 julius
   assign read_pointer_to_xilinx_ram = (read) ?
270
                                       read_pointer_preincremented :
271
                                       read_pointer;
272 485 julius
 
273 530 julius
   wire [8:0]                       write_pointer_to_xilinx_ram;
274
   assign write_pointer_to_xilinx_ram = {{(9-CNT_WIDTH){1'b0}},write_pointer};
275 485 julius
 
276 530 julius
   // synthesis translate_off
277
   // Port A - Write
278
   // Port B - Rread
279
   BLK_MEM_GEN_V3_1 #(
280
                      .C_ADDRA_WIDTH(9),
281
                      .C_ADDRB_WIDTH(9),
282
                      .C_ALGORITHM(1),
283
                      .C_BYTE_SIZE(9),
284
                      .C_COMMON_CLK(0),
285
                      .C_DEFAULT_DATA("0"),
286
                      .C_DISABLE_WARN_BHV_COLL(0),
287
                      .C_DISABLE_WARN_BHV_RANGE(0),
288
                      .C_FAMILY("virtex5"),
289
                      .C_HAS_ENA(0),
290
                      .C_HAS_ENB(0),
291
                      .C_HAS_INJECTERR(0),
292
                      .C_HAS_MEM_OUTPUT_REGS_A(0),
293
                      .C_HAS_MEM_OUTPUT_REGS_B(0),
294
                      .C_HAS_MUX_OUTPUT_REGS_A(0),
295
                      .C_HAS_MUX_OUTPUT_REGS_B(0),
296
                      .C_HAS_REGCEA(0),
297
                      .C_HAS_REGCEB(0),
298
                      .C_HAS_RSTA(0),
299
                      .C_HAS_RSTB(0),
300
                      .C_INITA_VAL("0"),
301
                      .C_INITB_VAL("0"),
302
                      .C_INIT_FILE_NAME("no_coe_file_loaded"),
303
                      .C_LOAD_INIT_FILE(0),
304
                      .C_MEM_TYPE(1),
305
                      .C_MUX_PIPELINE_STAGES(0),
306
                      .C_PRIM_TYPE(1),
307
                      .C_READ_DEPTH_A(512),
308
                      .C_READ_DEPTH_B(512),
309
                      .C_READ_WIDTH_A(32),
310
                      .C_READ_WIDTH_B(32),
311
                      .C_RSTRAM_A(0),
312
                      .C_RSTRAM_B(0),
313
                      .C_RST_PRIORITY_A("CE"),
314
                      .C_RST_PRIORITY_B("CE"),
315
                      .C_RST_TYPE("SYNC"),
316
                      .C_SIM_COLLISION_CHECK("WARNING_ONLY"),
317
                      .C_USE_BYTE_WEA(0),
318
                      .C_USE_BYTE_WEB(0),
319
                      .C_USE_DEFAULT_DATA(0),
320
                      .C_USE_ECC(0),
321
                      .C_WEA_WIDTH(1),
322
                      .C_WEB_WIDTH(1),
323
                      .C_WRITE_DEPTH_A(512),
324
                      .C_WRITE_DEPTH_B(512),
325
                      .C_WRITE_MODE_A("WRITE_FIRST"),
326
                      .C_WRITE_MODE_B("READ_FIRST"),
327
                      .C_WRITE_WIDTH_A(32),
328
                      .C_WRITE_WIDTH_B(32),
329
                      .C_XDEVICEFAMILY("virtex5"))
330
   inst (
331
         .CLKA(clk),
332
         .WEA(write),
333
         .ADDRA(write_pointer_to_xilinx_ram),
334
         .DINA(data_in),
335
         .CLKB(clk),
336
         .ADDRB(read_pointer_to_xilinx_ram),
337
         .DOUTB(data_out),
338
         .RSTA(reset),
339
         .ENA(),
340
         .REGCEA(),
341
         .DOUTA(),
342
         .RSTB(),
343
         .ENB(),
344
         .REGCEB(),
345
         .WEB(),
346
         .DINB(),
347
         .INJECTSBITERR(),
348
         .INJECTDBITERR(),
349
         .SBITERR(),
350
         .DBITERR(),
351
         .RDADDRECC()
352
         );
353
   // synthesis translate_on
354
   `endif //  `ifdef ETH_FIFO_RAMB18
355 6 julius
 
356
 
357 403 julius
 
358 530 julius
 `ifdef ETH_ALTERA_ALTSYNCRAM
359
   altera_dpram_16x32   altera_dpram_16x32_inst
360
   (
361
    .data             (data_in),
362
    .wren             (write & ~full),
363
    .wraddress        (clear ? {CNT_WIDTH-1{1'b0}} : write_pointer),
364
    .rdaddress        (clear ? {CNT_WIDTH-1{1'b0}} : read_pointer ),
365
    .clock            (clk),
366
    .q                (data_out)
367
    );  //exemplar attribute altera_dpram_16x32_inst NOOPT TRUE
368
 `endif //  `ifdef ETH_ALTERA_ALTSYNCRAM
369
 
370 6 julius
 
371 530 julius
endmodule // eth_fifo
372 6 julius
 

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