1 |
4 |
qaztronic |
//////////////////////////////////////////////////////////////////////
|
2 |
|
|
//// ////
|
3 |
|
|
//// Copyright (C) 2009 Authors and OPENCORES.ORG ////
|
4 |
|
|
//// ////
|
5 |
|
|
//// This source file may be used and distributed without ////
|
6 |
|
|
//// restriction provided that this copyright statement is not ////
|
7 |
|
|
//// removed from the file and that any derivative work contains ////
|
8 |
|
|
//// the original copyright notice and the associated disclaimer. ////
|
9 |
|
|
//// ////
|
10 |
|
|
//// This source file is free software; you can redistribute it ////
|
11 |
|
|
//// and/or modify it under the terms of the GNU Lesser General ////
|
12 |
|
|
//// Public License as published by the Free Software Foundation; ////
|
13 |
|
|
//// either version 2.1 of the License, or (at your option) any ////
|
14 |
|
|
//// later version. ////
|
15 |
|
|
//// ////
|
16 |
|
|
//// This source is distributed in the hope that it will be ////
|
17 |
|
|
//// useful, but WITHOUT ANY WARRANTY; without even the implied ////
|
18 |
|
|
//// warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR ////
|
19 |
|
|
//// PURPOSE. See the GNU Lesser General Public License for more ////
|
20 |
|
|
//// details. ////
|
21 |
|
|
//// ////
|
22 |
|
|
//// You should have received a copy of the GNU Lesser General ////
|
23 |
|
|
//// Public License along with this source; if not, download it ////
|
24 |
|
|
//// from http://www.opencores.org/lgpl.shtml ////
|
25 |
|
|
//// ////
|
26 |
|
|
//////////////////////////////////////////////////////////////////////
|
27 |
|
|
|
28 |
|
|
`timescale 1ns/10ps
|
29 |
|
|
|
30 |
|
|
|
31 |
|
|
module wb_size_bridge(
|
32 |
|
|
input wb_hi_clk_i,
|
33 |
|
|
input wb_hi_rst_i,
|
34 |
|
|
output [31:0] wb_hi_dat_o,
|
35 |
|
|
input [31:0] wb_hi_dat_i,
|
36 |
|
|
input [31:0] wb_hi_adr_i,
|
37 |
|
|
input wb_hi_cyc_i,
|
38 |
|
|
input wb_hi_stb_i,
|
39 |
|
|
input wb_hi_we_i,
|
40 |
|
|
input [3:0] wb_hi_sel_i,
|
41 |
|
|
output wb_hi_ack_o,
|
42 |
|
|
output wb_hi_err_o,
|
43 |
|
|
output wb_hi_rty_o,
|
44 |
|
|
|
45 |
|
|
output wb_lo_clk_o,
|
46 |
|
|
output wb_lo_rst_o,
|
47 |
|
|
input [15:0] wb_lo_dat_i,
|
48 |
|
|
output [15:0] wb_lo_dat_o,
|
49 |
|
|
output [31:0] wb_lo_adr_o,
|
50 |
|
|
output wb_lo_cyc_o,
|
51 |
|
|
output wb_lo_stb_o,
|
52 |
|
|
output wb_lo_we_o,
|
53 |
|
|
output [1:0] wb_lo_sel_o,
|
54 |
|
|
input wb_lo_ack_i,
|
55 |
|
|
input wb_lo_err_i,
|
56 |
|
|
input wb_lo_rty_i,
|
57 |
|
|
|
58 |
|
|
input lo_byte_if_i
|
59 |
|
|
);
|
60 |
|
|
|
61 |
|
|
// --------------------------------------------------------------------
|
62 |
|
|
// state machine encoder
|
63 |
|
|
reg [2:0] state_enc;
|
64 |
|
|
|
65 |
|
|
wire state_enc_3_more_chunks = state_enc[2];
|
66 |
|
|
wire state_enc_1_more_chunks = state_enc[1];
|
67 |
|
|
wire state_enc_error = state_enc[0];
|
68 |
|
|
|
69 |
|
|
always @(*)
|
70 |
|
|
case( { lo_byte_if_i, wb_hi_sel_i } )
|
71 |
|
|
5'b1_0001: state_enc = { 1'b0, 1'b0, 1'b0 };
|
72 |
|
|
5'b1_0010: state_enc = { 1'b0, 1'b0, 1'b0 };
|
73 |
|
|
5'b1_0100: state_enc = { 1'b0, 1'b0, 1'b0 };
|
74 |
|
|
5'b1_1000: state_enc = { 1'b0, 1'b0, 1'b0 };
|
75 |
|
|
5'b1_0011: state_enc = { 1'b0, 1'b1, 1'b0 };
|
76 |
|
|
5'b1_1100: state_enc = { 1'b0, 1'b1, 1'b0 };
|
77 |
|
|
5'b1_1111: state_enc = { 1'b1, 1'b0, 1'b0 };
|
78 |
|
|
5'b0_0001: state_enc = { 1'b0, 1'b0, 1'b0 };
|
79 |
|
|
5'b0_0010: state_enc = { 1'b0, 1'b0, 1'b0 };
|
80 |
|
|
5'b0_0100: state_enc = { 1'b0, 1'b0, 1'b0 };
|
81 |
|
|
5'b0_1000: state_enc = { 1'b0, 1'b0, 1'b0 };
|
82 |
|
|
5'b0_0011: state_enc = { 1'b0, 1'b0, 1'b0 };
|
83 |
|
|
5'b0_1100: state_enc = { 1'b0, 1'b0, 1'b0 };
|
84 |
|
|
5'b0_1111: state_enc = { 1'b0, 1'b1, 1'b0 };
|
85 |
|
|
default: state_enc = { 1'b0, 1'b0, 1'b1 };
|
86 |
|
|
endcase
|
87 |
|
|
|
88 |
|
|
|
89 |
|
|
// --------------------------------------------------------------------
|
90 |
|
|
// state machine
|
91 |
|
|
|
92 |
|
|
localparam STATE_DONT_CARE = 4'b????;
|
93 |
|
|
localparam STATE_PASS_THROUGH = 4'b0001;
|
94 |
|
|
localparam STATE_1_MORE_CHUNK = 4'b0010;
|
95 |
|
|
localparam STATE_2_MORE_CHUNK = 4'b0100;
|
96 |
|
|
localparam STATE_3_MORE_CHUNK = 4'b1000;
|
97 |
|
|
|
98 |
|
|
reg [3:0] state;
|
99 |
|
|
reg [3:0] next_state;
|
100 |
|
|
|
101 |
|
|
always @(posedge wb_hi_clk_i or posedge wb_hi_rst_i)
|
102 |
|
|
if(wb_hi_rst_i)
|
103 |
|
|
state <= STATE_PASS_THROUGH;
|
104 |
|
|
else
|
105 |
|
|
state <= next_state;
|
106 |
|
|
|
107 |
|
|
always @(*)
|
108 |
|
|
case( state )
|
109 |
|
|
STATE_PASS_THROUGH: if( state_enc_1_more_chunks & wb_lo_ack_i & wb_hi_stb_i & wb_hi_cyc_i )
|
110 |
|
|
next_state = STATE_1_MORE_CHUNK;
|
111 |
|
|
else if( state_enc_3_more_chunks & wb_lo_ack_i & wb_hi_stb_i & wb_hi_cyc_i )
|
112 |
|
|
next_state = STATE_3_MORE_CHUNK;
|
113 |
|
|
else
|
114 |
|
|
next_state = STATE_PASS_THROUGH;
|
115 |
|
|
|
116 |
|
|
STATE_3_MORE_CHUNK: if( wb_lo_ack_i )
|
117 |
|
|
next_state = STATE_2_MORE_CHUNK;
|
118 |
|
|
else
|
119 |
|
|
next_state = STATE_3_MORE_CHUNK;
|
120 |
|
|
|
121 |
|
|
STATE_2_MORE_CHUNK: if( wb_lo_ack_i )
|
122 |
|
|
next_state = STATE_1_MORE_CHUNK;
|
123 |
|
|
else
|
124 |
|
|
next_state = STATE_2_MORE_CHUNK;
|
125 |
|
|
|
126 |
|
|
STATE_1_MORE_CHUNK: if( wb_lo_ack_i )
|
127 |
|
|
next_state = STATE_PASS_THROUGH;
|
128 |
|
|
else
|
129 |
|
|
next_state = STATE_1_MORE_CHUNK;
|
130 |
|
|
|
131 |
|
|
default: next_state = STATE_PASS_THROUGH;
|
132 |
|
|
endcase
|
133 |
|
|
|
134 |
|
|
|
135 |
|
|
// --------------------------------------------------------------------
|
136 |
|
|
// byte enable & select
|
137 |
|
|
reg [3:0] byte_enable;
|
138 |
|
|
localparam BYTE_N_ENABLED = 4'b0000;
|
139 |
|
|
localparam BYTE_0_ENABLED = 4'b0001;
|
140 |
|
|
localparam BYTE_1_ENABLED = 4'b0010;
|
141 |
|
|
localparam BYTE_2_ENABLED = 4'b0100;
|
142 |
|
|
localparam BYTE_3_ENABLED = 4'b1000;
|
143 |
|
|
|
144 |
|
|
reg [1:0] byte_select;
|
145 |
|
|
localparam BYTE_0_SELECTED = 2'b00;
|
146 |
|
|
localparam BYTE_1_SELECTED = 2'b01;
|
147 |
|
|
localparam BYTE_2_SELECTED = 2'b10;
|
148 |
|
|
localparam BYTE_3_SELECTED = 2'b11;
|
149 |
|
|
localparam BYTE_X_SELECTED = 2'b??;
|
150 |
|
|
|
151 |
|
|
always @(*)
|
152 |
|
|
casez( { lo_byte_if_i, wb_hi_sel_i, state } )
|
153 |
|
|
{ 1'b1, 4'b0001, STATE_PASS_THROUGH }: byte_enable = BYTE_0_ENABLED;
|
154 |
|
|
{ 1'b1, 4'b0010, STATE_PASS_THROUGH }: byte_enable = BYTE_1_ENABLED;
|
155 |
|
|
{ 1'b1, 4'b0100, STATE_PASS_THROUGH }: byte_enable = BYTE_2_ENABLED;
|
156 |
|
|
{ 1'b1, 4'b1000, STATE_PASS_THROUGH }: byte_enable = BYTE_3_ENABLED;
|
157 |
|
|
|
158 |
|
|
{ 1'b1, 4'b0011, STATE_PASS_THROUGH }: byte_enable = BYTE_0_ENABLED;
|
159 |
|
|
{ 1'b1, 4'b0011, STATE_1_MORE_CHUNK }: byte_enable = BYTE_1_ENABLED;
|
160 |
|
|
|
161 |
|
|
{ 1'b1, 4'b1100, STATE_PASS_THROUGH }: byte_enable = BYTE_2_ENABLED;
|
162 |
|
|
{ 1'b1, 4'b1100, STATE_1_MORE_CHUNK }: byte_enable = BYTE_3_ENABLED;
|
163 |
|
|
|
164 |
|
|
{ 1'b1, 4'b1111, STATE_PASS_THROUGH }: byte_enable = BYTE_0_ENABLED;
|
165 |
|
|
{ 1'b1, 4'b1111, STATE_3_MORE_CHUNK }: byte_enable = BYTE_1_ENABLED;
|
166 |
|
|
{ 1'b1, 4'b1111, STATE_2_MORE_CHUNK }: byte_enable = BYTE_2_ENABLED;
|
167 |
|
|
{ 1'b1, 4'b1111, STATE_1_MORE_CHUNK }: byte_enable = BYTE_3_ENABLED;
|
168 |
|
|
|
169 |
|
|
{ 1'b0, 4'b????, STATE_DONT_CARE }: byte_enable = BYTE_N_ENABLED;
|
170 |
|
|
default: byte_enable = BYTE_N_ENABLED;
|
171 |
|
|
endcase
|
172 |
|
|
|
173 |
|
|
always @(*)
|
174 |
|
|
case( byte_enable )
|
175 |
|
|
BYTE_0_ENABLED: byte_select = BYTE_0_SELECTED;
|
176 |
|
|
BYTE_1_ENABLED: byte_select = BYTE_1_SELECTED;
|
177 |
|
|
BYTE_2_ENABLED: byte_select = BYTE_2_SELECTED;
|
178 |
|
|
BYTE_3_ENABLED: byte_select = BYTE_3_SELECTED;
|
179 |
|
|
default: byte_select = 2'bxx;
|
180 |
|
|
endcase
|
181 |
|
|
|
182 |
|
|
|
183 |
|
|
// --------------------------------------------------------------------
|
184 |
|
|
// word enable & select
|
185 |
|
|
reg [1:0] word_enable;
|
186 |
|
|
localparam WORD_N_ENABLED = 2'b00;
|
187 |
|
|
localparam WORD_0_ENABLED = 2'b01;
|
188 |
|
|
localparam WORD_1_ENABLED = 2'b10;
|
189 |
|
|
|
190 |
|
|
reg word_select;
|
191 |
|
|
localparam WORD_0_SELECTED = 1'b0;
|
192 |
|
|
localparam WORD_1_SELECTED = 1'b1;
|
193 |
|
|
localparam WORD_X_SELECTED = 1'b?;
|
194 |
|
|
|
195 |
|
|
always @(*)
|
196 |
|
|
casez( { lo_byte_if_i, wb_hi_sel_i, state } )
|
197 |
|
|
{ 1'b0, 4'b0011, STATE_PASS_THROUGH }: word_enable = WORD_0_ENABLED;
|
198 |
|
|
{ 1'b0, 4'b1100, STATE_PASS_THROUGH }: word_enable = WORD_1_ENABLED;
|
199 |
|
|
{ 1'b0, 4'b0001, STATE_PASS_THROUGH }: word_enable = WORD_0_ENABLED;
|
200 |
|
|
{ 1'b0, 4'b0010, STATE_PASS_THROUGH }: word_enable = WORD_0_ENABLED;
|
201 |
|
|
{ 1'b0, 4'b0100, STATE_PASS_THROUGH }: word_enable = WORD_1_ENABLED;
|
202 |
|
|
{ 1'b0, 4'b1000, STATE_PASS_THROUGH }: word_enable = WORD_1_ENABLED;
|
203 |
|
|
|
204 |
|
|
{ 1'b0, 4'b1111, STATE_PASS_THROUGH }: word_enable = WORD_0_ENABLED;
|
205 |
|
|
{ 1'b0, 4'b1111, STATE_1_MORE_CHUNK }: word_enable = WORD_1_ENABLED;
|
206 |
|
|
|
207 |
|
|
{ 1'b1, 4'b????, STATE_DONT_CARE }: word_enable = WORD_N_ENABLED;
|
208 |
|
|
default: word_enable = WORD_N_ENABLED;
|
209 |
|
|
endcase
|
210 |
|
|
|
211 |
|
|
always @(*)
|
212 |
|
|
case( word_enable )
|
213 |
|
|
WORD_0_ENABLED: word_select = WORD_0_SELECTED;
|
214 |
|
|
WORD_1_ENABLED: word_select = WORD_1_SELECTED;
|
215 |
|
|
default: word_select = 1'bx;
|
216 |
|
|
endcase
|
217 |
|
|
|
218 |
|
|
|
219 |
|
|
// --------------------------------------------------------------------
|
220 |
|
|
// write mux
|
221 |
|
|
reg [1:0] byte_write_mux_enc;
|
222 |
|
|
|
223 |
|
|
always @(*)
|
224 |
|
|
casez( {lo_byte_if_i, byte_select, word_select} )
|
225 |
|
|
{ 1'b1, BYTE_0_SELECTED, WORD_X_SELECTED }: byte_write_mux_enc = 2'b00;
|
226 |
|
|
{ 1'b1, BYTE_1_SELECTED, WORD_X_SELECTED }: byte_write_mux_enc = 2'b01;
|
227 |
|
|
{ 1'b1, BYTE_2_SELECTED, WORD_X_SELECTED }: byte_write_mux_enc = 2'b10;
|
228 |
|
|
{ 1'b1, BYTE_3_SELECTED, WORD_X_SELECTED }: byte_write_mux_enc = 2'b11;
|
229 |
|
|
{ 1'b0, BYTE_X_SELECTED, WORD_0_SELECTED }: byte_write_mux_enc = 2'b00;
|
230 |
|
|
{ 1'b0, BYTE_X_SELECTED, WORD_1_SELECTED }: byte_write_mux_enc = 2'b10;
|
231 |
|
|
default: byte_write_mux_enc = 2'b00;
|
232 |
|
|
endcase
|
233 |
|
|
|
234 |
|
|
reg [7:0] byte_write_mux;
|
235 |
|
|
|
236 |
|
|
always @(*)
|
237 |
|
|
case( byte_write_mux_enc )
|
238 |
|
|
2'b00: byte_write_mux = wb_hi_dat_i[7:0];
|
239 |
|
|
2'b01: byte_write_mux = wb_hi_dat_i[15:8];
|
240 |
|
|
2'b10: byte_write_mux = wb_hi_dat_i[23:16];
|
241 |
|
|
2'b11: byte_write_mux = wb_hi_dat_i[31:24];
|
242 |
|
|
default: byte_write_mux = wb_hi_dat_i[7:0];
|
243 |
|
|
endcase
|
244 |
|
|
|
245 |
|
|
reg [7:0] word_write_mux;
|
246 |
|
|
|
247 |
|
|
always @(*)
|
248 |
|
|
case( word_select )
|
249 |
|
|
WORD_0_SELECTED: word_write_mux = wb_hi_dat_i[15:8];
|
250 |
|
|
WORD_1_SELECTED: word_write_mux = wb_hi_dat_i[31:24];
|
251 |
|
|
default: word_write_mux = wb_hi_dat_i[15:8];
|
252 |
|
|
endcase
|
253 |
|
|
|
254 |
|
|
|
255 |
|
|
// --------------------------------------------------------------------
|
256 |
|
|
// read buffer & bypass mux
|
257 |
|
|
|
258 |
|
|
// low side input mux
|
259 |
|
|
wire [7:0] read_word_lo_mux = wb_lo_dat_i[7:0];
|
260 |
|
|
wire [7:0] read_word_hi_mux = ( word_enable[0] | word_enable[1] )? wb_lo_dat_i[15:8] : wb_lo_dat_i[7:0];
|
261 |
|
|
|
262 |
|
|
reg [31:0] read_buffer;
|
263 |
|
|
|
264 |
|
|
wire read_buffer_0_enable = (byte_enable[0] | word_enable[0]) & ~wb_hi_we_i;
|
265 |
|
|
wire read_buffer_1_enable = (byte_enable[1] | word_enable[0]) & ~wb_hi_we_i;
|
266 |
|
|
wire read_buffer_2_enable = (byte_enable[2] | word_enable[1]) & ~wb_hi_we_i;
|
267 |
|
|
wire read_buffer_3_enable = (byte_enable[3] | word_enable[1]) & ~wb_hi_we_i;
|
268 |
|
|
|
269 |
|
|
always @(posedge wb_hi_clk_i)
|
270 |
|
|
if( read_buffer_0_enable )
|
271 |
|
|
read_buffer[7:0] <= read_word_lo_mux;
|
272 |
|
|
|
273 |
|
|
always @(posedge wb_hi_clk_i)
|
274 |
|
|
if( read_buffer_1_enable )
|
275 |
|
|
read_buffer[15:8] <= read_word_hi_mux;
|
276 |
|
|
|
277 |
|
|
always @(posedge wb_hi_clk_i)
|
278 |
|
|
if( read_buffer_2_enable )
|
279 |
|
|
read_buffer[23:16] <= read_word_lo_mux;
|
280 |
|
|
|
281 |
|
|
always @(posedge wb_hi_clk_i)
|
282 |
|
|
if( read_buffer_3_enable )
|
283 |
|
|
read_buffer[31:24] <= read_word_hi_mux;
|
284 |
|
|
|
285 |
|
|
wire [31:0] read_buffer_mux;
|
286 |
|
|
|
287 |
|
|
// bypass read mux
|
288 |
|
|
assign read_buffer_mux[7:0] = read_buffer_0_enable ? read_word_lo_mux : read_buffer[7:0];
|
289 |
|
|
assign read_buffer_mux[15:8] = read_buffer_1_enable ? read_word_hi_mux : read_buffer[15:8];
|
290 |
|
|
assign read_buffer_mux[23:16] = read_buffer_2_enable ? read_word_lo_mux : read_buffer[23:16];
|
291 |
|
|
assign read_buffer_mux[31:24] = read_buffer_3_enable ? read_word_hi_mux : read_buffer[31:24];
|
292 |
|
|
|
293 |
|
|
|
294 |
|
|
// --------------------------------------------------------------------
|
295 |
|
|
// misc logic
|
296 |
|
|
wire [1:0] lo_addr_bits;
|
297 |
|
|
assign lo_addr_bits = ( |byte_enable ) ? byte_select : { word_select, 1'b0 };
|
298 |
|
|
|
299 |
|
|
wire all_done = ( ~(|state_enc) & (state == STATE_PASS_THROUGH) ) |
|
300 |
|
|
( |state_enc & (state == STATE_1_MORE_CHUNK) );
|
301 |
|
|
|
302 |
|
|
reg [1:0] wb_lo_sel_r;
|
303 |
|
|
always @(*)
|
304 |
|
|
casez( { lo_byte_if_i, wb_hi_sel_i, state } )
|
305 |
|
|
{ 1'b0, 4'b0001, STATE_PASS_THROUGH }: wb_lo_sel_r = 2'b01;
|
306 |
|
|
{ 1'b0, 4'b0010, STATE_PASS_THROUGH }: wb_lo_sel_r = 2'b10;
|
307 |
|
|
{ 1'b0, 4'b0100, STATE_PASS_THROUGH }: wb_lo_sel_r = 2'b01;
|
308 |
|
|
{ 1'b0, 4'b1000, STATE_PASS_THROUGH }: wb_lo_sel_r = 2'b10;
|
309 |
|
|
default: wb_lo_sel_r = 2'b11;
|
310 |
|
|
endcase
|
311 |
|
|
|
312 |
|
|
|
313 |
|
|
|
314 |
|
|
// --------------------------------------------------------------------
|
315 |
|
|
// output port assignments
|
316 |
|
|
assign wb_hi_dat_o = read_buffer_mux;
|
317 |
|
|
assign wb_hi_err_o = (wb_lo_err_i | state_enc_error) & wb_hi_stb_i & wb_hi_cyc_i;
|
318 |
|
|
assign wb_hi_rty_o = wb_lo_rty_i;
|
319 |
|
|
assign wb_hi_ack_o = all_done & wb_hi_stb_i & wb_hi_cyc_i & wb_lo_ack_i;
|
320 |
|
|
|
321 |
|
|
assign wb_lo_adr_o = { wb_hi_adr_i[31:2], lo_addr_bits };
|
322 |
|
|
assign wb_lo_clk_o = wb_hi_clk_i;
|
323 |
|
|
assign wb_lo_rst_o = wb_hi_rst_i;
|
324 |
|
|
assign wb_lo_cyc_o = wb_hi_cyc_i;
|
325 |
|
|
assign wb_lo_stb_o = wb_hi_stb_i;
|
326 |
|
|
assign wb_lo_we_o = wb_hi_we_i & wb_hi_stb_i & wb_hi_cyc_i;
|
327 |
|
|
assign wb_lo_dat_o = {word_write_mux, byte_write_mux};
|
328 |
|
|
assign wb_lo_sel_o = wb_lo_sel_r;
|
329 |
|
|
|
330 |
|
|
|
331 |
|
|
endmodule
|
332 |
|
|
|
333 |
|
|
|