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[/] [openrisc/] [trunk/] [orpsocv2/] [rtl/] [verilog/] [wb_ram_b3/] [wb_ram_b3.v] - Blame information for rev 456

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// Version 5
 
//`define RANDOM_ACK_NEGATION
 
module wb_ram_b3(
                 wb_adr_i, wb_bte_i, wb_cti_i, wb_cyc_i, wb_dat_i, wb_sel_i,
                 wb_stb_i, wb_we_i,
 
                 wb_ack_o, wb_err_o, wb_rty_o, wb_dat_o,
 
                 wb_clk_i, wb_rst_i);
 
   // Memory parameters
   parameter dw = 32;
 
   // 32MB memory by default
   parameter aw = 23;
   parameter mem_size  = 8388608;
 
   input [aw-1:0]        wb_adr_i;
   input [1:0]           wb_bte_i;
   input [2:0]           wb_cti_i;
   input                wb_cyc_i;
   input [dw-1:0]        wb_dat_i;
   input [3:0]           wb_sel_i;
   input                wb_stb_i;
   input                wb_we_i;
 
   output               wb_ack_o;
   output               wb_err_o;
   output               wb_rty_o;
   output [dw-1:0]       wb_dat_o;
 
   input                wb_clk_i;
   input                wb_rst_i;
 
 
   // synthesis attribute ram_style of mem is block
   reg [dw-1:0]  mem [ 0 : mem_size-1 ]  /* verilator public */ /* synthesis ram_style = no_rw_check */;
 
   //reg [aw-1:2] wb_adr_i_r;
   reg [aw-1:0] adr;
 
   wire [31:0]                      wr_data;
 
   // Register to indicate if the cycle is a Wishbone B3-registered feedback 
   // type access
   reg                             wb_b3_trans;
   wire                            wb_b3_trans_start, wb_b3_trans_stop;
 
   // Register to use for counting the addresses when doing burst accesses
   reg [aw-1:0]  burst_adr_counter;
   reg [2:0]                        wb_cti_i_r;
   reg [1:0]                        wb_bte_i_r;
   wire                            using_burst_adr;
   wire                            burst_access_wrong_wb_adr;
 
   reg                             random_ack_negate;
 
   // Logic to detect if there's a burst access going on
   assign wb_b3_trans_start = ((wb_cti_i == 3'b001)|(wb_cti_i == 3'b010)) &
                              wb_stb_i & !wb_b3_trans;
 
   assign  wb_b3_trans_stop = (wb_cti_i == 3'b111) &
                              wb_stb_i & wb_b3_trans & wb_ack_o;
 
   always @(posedge wb_clk_i)
     if (wb_rst_i)
       wb_b3_trans <= 0;
     else if (wb_b3_trans_start)
       wb_b3_trans <= 1;
     else if (wb_b3_trans_stop)
       wb_b3_trans <= 0;
 
   // Burst address generation logic
   always @*
     if (wb_rst_i)
       burst_adr_counter = 0;
     else if (wb_b3_trans_start)
       burst_adr_counter = {2'b00,wb_adr_i[aw-1:2]};
     else if ((wb_cti_i_r == 3'b010) & wb_ack_o & wb_b3_trans)
       // Incrementing burst
       begin
          if (wb_bte_i_r == 2'b00) // Linear burst
            burst_adr_counter = adr + 1;
          if (wb_bte_i_r == 2'b01) // 4-beat wrap burst
            burst_adr_counter[1:0] = adr[1:0] + 1;
          if (wb_bte_i_r == 2'b10) // 8-beat wrap burst
            burst_adr_counter[2:0] = adr[2:0] + 1;
          if (wb_bte_i_r == 2'b11) // 16-beat wrap burst
            burst_adr_counter[3:0] = adr[3:0] + 1;
       end // if ((wb_cti_i_r == 3'b010) & wb_ack_o_r)
     else if (!wb_ack_o & wb_b3_trans)
            burst_adr_counter = adr;
 
 
   always @(posedge wb_clk_i)
     wb_bte_i_r <= wb_bte_i;
 
   // Register it locally
   always @(posedge wb_clk_i)
     wb_cti_i_r <= wb_cti_i;
 
   assign using_burst_adr = wb_b3_trans;
 
   assign burst_access_wrong_wb_adr = (using_burst_adr & (adr != {2'b00,wb_adr_i[aw-1:2]}));
 
   // Address registering logic
   always@(posedge wb_clk_i)
     if(wb_rst_i)
       adr <= 0;
     else if (using_burst_adr)
       adr <= burst_adr_counter;
     else if (wb_cyc_i & wb_stb_i)
       adr <= {2'b00,wb_adr_i[aw-1:2]};
 
   parameter memory_file = "sram.vmem";
 
 
`ifdef verilator
 
   task do_readmemh;
      // verilator public
      $readmemh(memory_file, mem);
   endtask // do_readmemh
 
`else
 
   initial
     begin
        $readmemh(memory_file, mem);
     end
 
`endif // !`ifdef verilator
 
 
   // Function to access RAM (for use by Verilator).
   function [31:0] get_mem;
      // verilator public
      input [aw-1:0]             addr;
      get_mem = mem[addr];
   endfunction // get_mem
 
   // Function to write RAM (for use by Verilator).
   function set_mem;
      // verilator public
      input [aw-1:0]             addr;
      input [dw-1:0]             data;
      mem[addr] = data;
   endfunction // set_mem
 
 
   assign wb_rty_o = 0;
 
   // mux for data to ram, RMW on part sel != 4'hf
   assign wr_data[31:24] = wb_sel_i[3] ? wb_dat_i[31:24] : wb_dat_o[31:24];
   assign wr_data[23:16] = wb_sel_i[2] ? wb_dat_i[23:16] : wb_dat_o[23:16];
   assign wr_data[15: 8] = wb_sel_i[1] ? wb_dat_i[15: 8] : wb_dat_o[15: 8];
   assign wr_data[ 7: 0] = wb_sel_i[0] ? wb_dat_i[ 7: 0] : wb_dat_o[ 7: 0];
 
   // Address logic
   /*
   always @(posedge wb_clk_i)
     begin
        if (wb_rst_i)
          wb_adr_i_r <= 0;
        else
          if (wb_cyc_i & wb_stb_i)
            wb_adr_i_r <= wb_adr_i[aw-1:2];
     end
    */
 
   wire ram_we;
   assign ram_we = wb_we_i & wb_ack_o;
 
   assign wb_dat_o = mem[adr];
 
   // Write logic
   always @ (posedge wb_clk_i)
     begin
        if (ram_we)
          mem[adr] <= wr_data;
     end
 
   // Ack Logic
   reg wb_ack_o_r;
 
   assign wb_ack_o = wb_ack_o_r & wb_stb_i;
 
   always @(posedge wb_clk_i)
     if (wb_rst_i)
       begin
          wb_ack_o_r <= 1'b0;
       end
     else if (wb_cyc_i) // We have bus
       begin
          if (wb_cti_i == 3'b111)
            begin
               // End of burst
               if (wb_ack_o_r)
                 // ALWAYS de-assert ack after burst end
                 wb_ack_o_r <= 0;
               else if (wb_stb_i & !random_ack_negate)
                 wb_ack_o_r <= 1;
               else
                 wb_ack_o_r <= 0;
            end
          else if (wb_cti_i == 3'b000)
            begin
               // Classic cycle acks
               if (wb_stb_i & !random_ack_negate)
                 begin
                    if (!wb_ack_o_r)
                      wb_ack_o_r <= 1;
                    else
                      wb_ack_o_r <= 0;
                 end
               else
                 wb_ack_o_r <= 0;
            end // if (wb_cti_i == 3'b000)
          else if ((wb_cti_i == 3'b001) | (wb_cti_i == 3'b010))
            begin
               // Increment/constant address bursts
               if (wb_stb_i & !random_ack_negate)
                 wb_ack_o_r <= 1;
               else
                 wb_ack_o_r <= 0;
            end
          else if (wb_cti_i == 3'b111)
            begin
               // End of cycle
               if (wb_stb_i & !random_ack_negate)
                 wb_ack_o_r <= 1;
               else
                 wb_ack_o_r <= 0;
            end
       end // if (wb_cyc_i)
     else
       wb_ack_o_r <= 0;
 
   assign wb_err_o = 1'b0;// wb_ack_o & (burst_access_wrong_wb_adr); // OR in other errors here
 
 
   // Random ACK negation logic
`ifdef RANDOM_ACK_NEGATION
   reg [31:0] lfsr;
   always @(posedge wb_clk_i)
     if (wb_rst_i)
       lfsr <= 32'h273e2d4a;
     else lfsr <= {lfsr[30:0], ~(lfsr[30]^lfsr[6]^lfsr[4]^lfsr[1]^lfsr[0])};
 
   always @(posedge wb_clk_i)
     random_ack_negate <= lfsr[26];
 
`else
   always @(wb_rst_i)
     random_ack_negate = 0;
`endif
 
 
 
endmodule // wb_ram_b3_v2
 

Line No.	Rev	Author	Line
1	351	julius
2			`// Version 5`
3
4			//`define RANDOM_ACK_NEGATION
5
6			`module wb_ram_b3(`
7			`wb_adr_i, wb_bte_i, wb_cti_i, wb_cyc_i, wb_dat_i, wb_sel_i,`
8			`wb_stb_i, wb_we_i,`
9
10			`wb_ack_o, wb_err_o, wb_rty_o, wb_dat_o,`
11
12			`wb_clk_i, wb_rst_i);`
13
14			`// Memory parameters`
15			`parameter dw = 32;`
16
17			`// 32MB memory by default`
18	363	julius	`parameter aw = 23;`
19	351	julius	`parameter mem_size = 8388608;`
20
21			`input [aw-1:0] wb_adr_i;`
22			`input [1:0] wb_bte_i;`
23			`input [2:0] wb_cti_i;`
24			`input wb_cyc_i;`
25			`input [dw-1:0] wb_dat_i;`
26			`input [3:0] wb_sel_i;`
27			`input wb_stb_i;`
28			`input wb_we_i;`
29
30			`output wb_ack_o;`
31			`output wb_err_o;`
32			`output wb_rty_o;`
33			`output [dw-1:0] wb_dat_o;`
34
35			`input wb_clk_i;`
36			`input wb_rst_i;`
37
38
39			`// synthesis attribute ram_style of mem is block`
40			`reg [dw-1:0] mem [ 0 : mem_size-1 ] /* verilator public / / synthesis ram_style = no_rw_check */;`
41
42			`//reg [aw-1:2] wb_adr_i_r;`
43	363	julius	`reg [aw-1:0] adr;`
44	351	julius
45			`wire [31:0] wr_data;`
46
47			`// Register to indicate if the cycle is a Wishbone B3-registered feedback`
48			`// type access`
49			`reg wb_b3_trans;`
50			`wire wb_b3_trans_start, wb_b3_trans_stop;`
51
52			`// Register to use for counting the addresses when doing burst accesses`
53	363	julius	`reg [aw-1:0] burst_adr_counter;`
54	351	julius	`reg [2:0] wb_cti_i_r;`
55			`reg [1:0] wb_bte_i_r;`
56			`wire using_burst_adr;`
57			`wire burst_access_wrong_wb_adr;`
58
59			`reg random_ack_negate;`
60
61			`// Logic to detect if there's a burst access going on`
62			`assign wb_b3_trans_start = ((wb_cti_i == 3'b001)\|(wb_cti_i == 3'b010)) &`
63			`wb_stb_i & !wb_b3_trans;`
64
65			`assign wb_b3_trans_stop = (wb_cti_i == 3'b111) &`
66			`wb_stb_i & wb_b3_trans & wb_ack_o;`
67
68			`always @(posedge wb_clk_i)`
69			`if (wb_rst_i)`
70			`wb_b3_trans <= 0;`
71			`else if (wb_b3_trans_start)`
72			`wb_b3_trans <= 1;`
73			`else if (wb_b3_trans_stop)`
74			`wb_b3_trans <= 0;`
75
76			`// Burst address generation logic`
77	353	julius	`always @*`
78	351	julius	`if (wb_rst_i)`
79	353	julius	`burst_adr_counter = 0;`
80	351	julius	`else if (wb_b3_trans_start)`
81	363	julius	`burst_adr_counter = {2'b00,wb_adr_i[aw-1:2]};`
82	351	julius	`else if ((wb_cti_i_r == 3'b010) & wb_ack_o & wb_b3_trans)`
83			`// Incrementing burst`
84			`begin`
85			`if (wb_bte_i_r == 2'b00) // Linear burst`
86	353	julius	`burst_adr_counter = adr + 1;`
87	351	julius	`if (wb_bte_i_r == 2'b01) // 4-beat wrap burst`
88	353	julius	`burst_adr_counter[1:0] = adr[1:0] + 1;`
89	351	julius	`if (wb_bte_i_r == 2'b10) // 8-beat wrap burst`
90	353	julius	`burst_adr_counter[2:0] = adr[2:0] + 1;`
91	351	julius	`if (wb_bte_i_r == 2'b11) // 16-beat wrap burst`
92	353	julius	`burst_adr_counter[3:0] = adr[3:0] + 1;`
93	351	julius	`end // if ((wb_cti_i_r == 3'b010) & wb_ack_o_r)`
94			`else if (!wb_ack_o & wb_b3_trans)`
95	353	julius	`burst_adr_counter = adr;`
96	351	julius
97
98			`always @(posedge wb_clk_i)`
99			`wb_bte_i_r <= wb_bte_i;`
100
101			`// Register it locally`
102			`always @(posedge wb_clk_i)`
103			`wb_cti_i_r <= wb_cti_i;`
104
105			`assign using_burst_adr = wb_b3_trans;`
106
107	363	julius	`assign burst_access_wrong_wb_adr = (using_burst_adr & (adr != {2'b00,wb_adr_i[aw-1:2]}));`
108	351	julius
109			`// Address registering logic`
110			`always@(posedge wb_clk_i)`
111			`if(wb_rst_i)`
112			`adr <= 0;`
113			`else if (using_burst_adr)`
114			`adr <= burst_adr_counter;`
115			`else if (wb_cyc_i & wb_stb_i)`
116	363	julius	`adr <= {2'b00,wb_adr_i[aw-1:2]};`
117	351	julius
118			`parameter memory_file = "sram.vmem";`
119
120
121			`ifdef verilator
122
123			`task do_readmemh;`
124			`// verilator public`
125			`$readmemh(memory_file, mem);`
126			`endtask // do_readmemh`
127
128			`else
129
130			`initial`
131			`begin`
132			`$readmemh(memory_file, mem);`
133			`end`
134
135			`endif // !`ifdef verilator
136
137
138			`// Function to access RAM (for use by Verilator).`
139			`function [31:0] get_mem;`
140			`// verilator public`
141			`input [aw-1:0] addr;`
142			`get_mem = mem[addr];`
143			`endfunction // get_mem`
144
145			`// Function to write RAM (for use by Verilator).`
146			`function set_mem;`
147			`// verilator public`
148			`input [aw-1:0] addr;`
149			`input [dw-1:0] data;`
150			`mem[addr] = data;`
151			`endfunction // set_mem`
152
153
154			`assign wb_rty_o = 0;`
155
156			`// mux for data to ram, RMW on part sel != 4'hf`
157			`assign wr_data[31:24] = wb_sel_i[3] ? wb_dat_i[31:24] : wb_dat_o[31:24];`
158			`assign wr_data[23:16] = wb_sel_i[2] ? wb_dat_i[23:16] : wb_dat_o[23:16];`
159			`assign wr_data[15: 8] = wb_sel_i[1] ? wb_dat_i[15: 8] : wb_dat_o[15: 8];`
160			`assign wr_data[ 7: 0] = wb_sel_i[0] ? wb_dat_i[ 7: 0] : wb_dat_o[ 7: 0];`
161
162			`// Address logic`
163			`/*`
164			`always @(posedge wb_clk_i)`
165			`begin`
166			`if (wb_rst_i)`
167			`wb_adr_i_r <= 0;`
168			`else`
169			`if (wb_cyc_i & wb_stb_i)`
170			`wb_adr_i_r <= wb_adr_i[aw-1:2];`
171			`end`
172			`*/`
173
174			`wire ram_we;`
175			`assign ram_we = wb_we_i & wb_ack_o;`
176
177			`assign wb_dat_o = mem[adr];`
178
179			`// Write logic`
180			`always @ (posedge wb_clk_i)`
181			`begin`
182			`if (ram_we)`
183			`mem[adr] <= wr_data;`
184			`end`
185
186			`// Ack Logic`
187			`reg wb_ack_o_r;`
188
189			`assign wb_ack_o = wb_ack_o_r & wb_stb_i;`
190
191	353	julius	`always @(posedge wb_clk_i)`
192	351	julius	`if (wb_rst_i)`
193			`begin`
194			`wb_ack_o_r <= 1'b0;`
195			`end`
196			`else if (wb_cyc_i) // We have bus`
197			`begin`
198			`if (wb_cti_i == 3'b111)`
199			`begin`
200			`// End of burst`
201			`if (wb_ack_o_r)`
202			`// ALWAYS de-assert ack after burst end`
203			`wb_ack_o_r <= 0;`
204			`else if (wb_stb_i & !random_ack_negate)`
205			`wb_ack_o_r <= 1;`
206			`else`
207			`wb_ack_o_r <= 0;`
208			`end`
209			`else if (wb_cti_i == 3'b000)`
210			`begin`
211			`// Classic cycle acks`
212			`if (wb_stb_i & !random_ack_negate)`
213			`begin`
214			`if (!wb_ack_o_r)`
215			`wb_ack_o_r <= 1;`
216			`else`
217			`wb_ack_o_r <= 0;`
218			`end`
219			`else`
220			`wb_ack_o_r <= 0;`
221			`end // if (wb_cti_i == 3'b000)`
222			`else if ((wb_cti_i == 3'b001) \| (wb_cti_i == 3'b010))`
223			`begin`
224			`// Increment/constant address bursts`
225			`if (wb_stb_i & !random_ack_negate)`
226			`wb_ack_o_r <= 1;`
227			`else`
228			`wb_ack_o_r <= 0;`
229			`end`
230			`else if (wb_cti_i == 3'b111)`
231			`begin`
232			`// End of cycle`
233			`if (wb_stb_i & !random_ack_negate)`
234			`wb_ack_o_r <= 1;`
235			`else`
236			`wb_ack_o_r <= 0;`
237			`end`
238			`end // if (wb_cyc_i)`
239			`else`
240			`wb_ack_o_r <= 0;`
241
242			`assign wb_err_o = 1'b0;// wb_ack_o & (burst_access_wrong_wb_adr); // OR in other errors here`
243
244
245			`// Random ACK negation logic`
246			`ifdef RANDOM_ACK_NEGATION
247			`reg [31:0] lfsr;`
248			`always @(posedge wb_clk_i)`
249			`if (wb_rst_i)`
250			`lfsr <= 32'h273e2d4a;`
251			`else lfsr <= {lfsr[30:0], ~(lfsr[30]^lfsr[6]^lfsr[4]^lfsr[1]^lfsr[0])};`
252
253			`always @(posedge wb_clk_i)`
254			`random_ack_negate <= lfsr[26];`
255
256			`else
257			`always @(wb_rst_i)`
258	353	julius	`random_ack_negate = 0;`
259	351	julius	`endif
260
261
262
263			`endmodule // wb_ram_b3_v2`
264

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